Racecar Engineering Le Mans 2019

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Le Mans 2019 Tech preview of the world’s greatest race

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CONTENTS AND WELCOME

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Ricardo Divila Why a grasp of languages is a huge advantage for a race engineer The TS saga The full story of Toyota’s quest to win the Le Mans 24 hours Current thinking Could the push towards electrification be misguided?

Hydrogen in motorsport How and why fuel cell racecars are becoming more and more viable Hydrogen part 2 We get under the skin of the LMPH2G fuel cell racer

Produced by Racecar Engineering editorial team

T

his supplement focusses largely on the drivetrain technologies that could be implemented at Le Mans in the next decade, with hydrogen forming a major part of the ACO’s long term vision. Bernard Niclot, formerly technical director at the FIA, is now in the process of finalising the regulations and he expects to have them fixed by the end of 2019, and that there will be ‘multiple manufacturers’ with cars on the grid in a separate class of the Le Mans 24 hours by 2024. In the interim, at Le Mans this year the FIA and ACO finally confirmed the hypercar regulations. The details have begun to emerge and manufacturers have now started to commit to it.

Manufacturers have the option to bring a hybrid or non-hybrid prototype, a hybrid or a non-hybrid road car, and the ACO and FIA will also grandfather the existing privateer LMP1 cars for a further year, through the 2020/21 season. There will be a single tyre supplier for the series, although Michelin and Dunlop are both against this plan. However, the balance of performance for the category does rather limit the FIA and ACO’s options. Power will be limited to 550kW, the power curve will have to be similar for all drivetrain options, and fuel flow limitations will be eliminated from the category. Weight and weight distribution are major concerns for the organising bodies. The weight will be 1100kg, but the weight distribution will be different for each car concept.

Aston Martin was the first of the manufacturers to commit ‘at least’ two Valkyries that are expected to compete without the hybrid system. It hopes that there will also be customer cars, but could not confirm this. Multimatic, which

developed the road and race GTs for Ford, will undertake the same programme with the Valkyrie, having already been announced as the provider for the road car chassis. Aston Martin Lagonda chairman Andy Palmer did not announce who would run the factory cars, saying that the contracts were not yet in place, but that he hopes to be in a position to do so ‘within the next two to three weeks.’

Key to Aston’s participation is the limitation of four-wheel drive so that it is not such a performance differentiator. At the Le Mans test day it was agreed that the front-wheel drive hybrid system would only be able to be activated above 120km/h, as it was in 2012 and 2013. In the wet, it will be above 140km/h.

FIA President Jean Todt has been active in these negotiations and has insisted that, as a World Championship, the balance of performance must be an automated system. The FIA and ACO will therefore take the principles of the system used in GTE and apply them to their top class, having minimal human involvement in the process. The FIA World Endurance Championship started with open technical regulations, allowing petrol, diesel, and options in hybrid that included super capacitors, flywheels and batteries. They have now adopted this same approach with their new regulations, and everyone at Le Mans hopes that they will be as successful as they were before.

ANDREW COTTON Editor

RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT www.racecar-engineering.com 3

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STRAIGHT TALK – RICARDO DIVILA

Lost in translation Why a good grasp of foreign languages is a very useful tool for the race engineer

E

nglish has become the lingua franca of the world, something probably related to the spread of the British Empire, then with the American move to hegemony in a polarised postwar world. In racing there is no escaping English, as the sport’s official language, too.

Even the FIA, a French-heavy ruling body, bowed to this in writing the technical and sporting regulations for racing in English – those used for final arbitration – due to the number of British F1 teams, who brought all their lobbying efforts to bear to ensure this was the case.

Up until then I had successfully used my knowledge of the French version to open up loopholes to be exploited, and some years ago it was most entertaining to see Peter Warr and John Surtees at a Brazilian GP scrutineering, purple faced and frothing at the mouth after protesting one of my interpretations and being told: ‘The French version is final’.

often had to interject the caveat ‘What he really means is (explanation)’ when I could see the looming misunderstanding. It could become rather contentious later if it involved money.

There were even more awkward moments when doing direct translation when the interlocutor didn’t speak English at all. He rambled on for a couple of minutes, me doing a question in a short burst, getting the compact answer, then speaking for several minutes to convey the same information. This, of course, left the Anglophones thinking that I was either making things up or not translating everything, and the others confused at the shortness of the answer they heard in English compared to their translation.

The whole issue is the reason for the European epithet ‘Perfidious Albion’, resulting from all the

people to think critically about the government, or even to contemplate that they might be impoverished or oppressed, by reducing the number of words to reduce the thoughts of the person. In other words ‘we shape our tools then they shape us’. Language is a tool.

Speaking in tongues

Technical meetings at the FIA were even more entertaining on the endurance side, as most of the participants used the common English to adjudicate and decide where to go to in future rules, but were then using a second language otherwise. Hearing the muttered discussions in French, Italian or German of the relevant representatives on the sidelines when debating a point could be surreal.

We will not even go into the attempts to translate the proceedings into Japanese for my erstwhile employer. The use of the word ‘Hai’ (Yes) in Japanese does not mean agreement, not even ‘I During my early days in Japan, when I was understand’, but merely ‘I have heard’. still trying to learn the language, the team Having acquired 11 languages of thought I actually did understand it well, different roots; English from my mother, for I could follow any technical discussion Portuguese from the environment (Brazil) quite easily, as all the jargon terms were in and Czech, this gave a good base for English. After all, when the subject of car other Anglo-Saxon, Slav and Romance handling is being discussed the phrase languages, plus nine years of Latin at ‘Chotto understeer, tabun front camber school led to an ease in learning them.

Motor racing is very good at communicating clearly when it needs matawa katai rear bar yoku narimasu,’ is I had thought that comprehension was to, but in a global sport the language barrier can cause problems practically self-explanatory, if you grasp a given, until a completely non-western the basics of vehicle dynamics. language thought process derailed my English does have several advantages, too; cortex. It’s more complicated than we think. treaties and business deals done in the past, both like German it is concise and to the point, for no Ludwig Wittgenstein’s dictum ‘if a lion could sides having proclaimed their bona fides, but known historical reason, it just is. As proof, look talk, we should not be able to understand him’, tripping over the perceived meaning. at the FIA Regulations themselves, the English means that the language games of lions are too Likewise the Brits view all other nationalities version being several pages shorter than the different from our own to permit understanding. darkly, muttering that they ‘don’t do whatever French, and more concrete in its definitions.

There is something in this theory. they have agreed to’, when really it is just different When trying to describe a permitted action This will lead to different interpretations; after ways of understanding words or phrases. It could English is quite precise, whereas in the Romance all, we see the same thing even in the thought conceivably have led to the dreaded ‘B’ word that is languages you have to put fences around the patterns of common language speakers of convulsing the UK now, but we will not go there. definition stating ‘X is not permitted, neither is Y different political leanings. Throw in words with or Z. And no, neither is W’, to corral the thrust of different linguistic roots and it will be chaos.

The Sapir-Whorf hypothesis of linguistic relativity the regulation. The phrase ‘anything not explicitly Taking all this into consideration – plus the holds that the structure of a language affects its authorised is forbidden’ is a stop to that problem, fact that we don’t even have a common electrical speakers’ world view or cognition. It hasn’t been and sounds awkward in English, but makes plug all over the world, each nation having its own formally adopted, but we can see its thrust in complete sense in the looser languages. preferred version – I cannot help but postulate examples like Orwell’s Newspeak in the seminal Having often been in meetings with French, that Shakespeare’s ‘confusion hath made it’s novel, 1984. It is where not having the words, and Italian, Brazilian and Spanish native speakers who masterpiece’ will continue to flourish, and not thus the concepts, would make it impossible for also spoke English in a discussion with a Brit, I only in the world of motor racing.

Talk the torque

Bad language

The phrase ‘anything not explicitly authorised is forbidden’ sounds awkward in English, but makes complete sense in some other languages RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT www.racecar-engineering.com 5

LE MANS 2019 – TOYOTA

TS

The dynasty

Toyota introduced the first of its ‘TS’ cars in 1991 but it wasn’t until last year that one finally triumphed at Le Mans. We trace the technical development of this illustrious line to find out how the manufacturer finally discovered the secret to winning the 24 hours

By ANDREW COTTON

T

oyota is these days the last manufacturer standing in the LMP1 category of the FIA World Endurance Championship. Its programme is paid for by the company’s research and development department in Japan, but its actual development path has plateaued in the last five years as the manufacturer competition has slowly depleted, Audi leaving in 2016 and Porsche following it out of the door the year after.

The three manufacturers tried to find ways to save costs, and elected to only renew chassis every two years, meaning that the TS030 and 040 followed that pattern. However, with the withdrawal of Audi and Porsche, the 050 has run from 2016 to the present day. Yet it is still dominating the championship.

The current car is the quickest ever seen at Le Mans, having set an all-time fastest lap in 2017 of 3m14.791s, with Kamui Kobayashi at the wheel, at an

average speed of 251.9km/h. The 050 features more than 1000PS, weighs slightly under 900kg, and packs a twin-turbocharged 2.4-litre engine. It has crossed the line first in every round of the 2018/19 WEC season and in 2018 it became only the second car from a Japanese manufacturer to ever win at Le Mans; Mazda was the first back in 1991.

That was also the year that Toyota started its ‘TS’ naming process with the all-new TS010, featuring a 3.5-litre normally aspirated engine, a formula that had been decided upon by the FIA to encourage manufacturers to go to Formula 1 (which was then using this engine configuration). Toyota built the engine, but it didn’t go to Formula 1 for a further decade. The TS010 was designed by Tony Southgate and built at TRD (Toyota Racing Developments), but it was run at Le Mans by TOM’s GB, which operated out of a Toyota-owned facility in Norfolk, UK.

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The current car is the quickest ever seen at Le Mans, having set an all-time fastest lap in 2017 of 3m14.791s

After 27 years of trying a Toyota ‘TS’ car finally won Le Mans last year RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT www.racecar-engineering.com 7

LE MANS 2019 – TOYOTA

The TS050 is the most recent of the TS family of racecars

The racecar was fast enough to take on the Peugeot 905, but the team already knew this was not going to be a successful season. ‘We knew that the car had a problem from during the start of the testing,’ remembers Hiroshi Fushida, president of TOM’s GB at the time.

‘The gearbox was the issue. It was a very heavy gearbox, and almost impossible to shift. After 20 hours, no one wanted to drive the car, it was so heavy. It was internally made at Toyota, but the guy who designed the gearbox didn’t have any racing gearbox experience. He was a good guy to design the production gearbox.

I proposed that we use the sequential shift, easier for the drivers and less damaging to the gearbox, but he didn’t want to listen.’

The gearbox wasn’t the only issue; the low minimum weight of 800kg meant that the whole car was built with minimum materials, and the floor was not strong enough to cope with the rigours of 24-hour racing. The 010 raced in three seasons, winning three of its 10 races, but that elusive win at Le Mans never transpired.

The TS020

After the programme finished, TOM’s had to find projects so as to keep racing, so it designed cars for the British and Japanese touring car championships, and for British and Spanish F3 through the 1990s. However, for Toyota it designed a 2-litre, 4-cylinder open top car for the LMP675 category for cars weighing 675kg.

‘It was a very small budget, and we tested with Tom Kristensen at Snetterton and it was very quick, but it was only an experimental project, unfortunately,’ laments Fushida.

The car was sent to TMG in Cologne, and Fushida believes that some learning was carried over into the TS020 that TMG then created. ‘It was a venturi car,’ says Fushida, and this was also evident on the TS020, which featured deep tunnels under the car to create downforce. This car, more commonly known as the GT-One, was introduced in 1998 and was the first to be

The Toyota TS010 was a very quick racecar but it was never really quite strong enough to win the Le Mans 24 hours

designed entirely on CAD, designer Andre de Cortenze almost developing a phobia of pens and pencils. There were drawing offices still in the building at TMG, but they were not used.

The integration engineer at the time was John Litjens, a Dutchman who was also the race engineer on the number 3 car of Ukyo Katayama, Keiichi Tsuchiya and Toshio Suzuki, and has since risen to become project leader on the Le Mans programme. ‘At that time, CAD was coming up and you had to have a trust in that,’ remembers Litjens. ‘On the other hand, if you look at what we do now, with the full data management system on desks to make sure you can find your bill of materials structure, that then didn’t exist. I was an integration engineer and I had to get the team to build this mock up. I knew which designer was doing which part, so I knew on which CAD station to look for the information, but it was not like now where you have a vertical tree built up and you have the car there, this didn’t exist.’

The car was closed cockpit, which meant that the team had to design in doors, hinges and windscreen wipers. The lower and upper part of the chassis were bonded – it was another three

years before the former TOM’s facility in Norfolk, by then owned by Audi, built the first one-piece tub for the Bentley EXP Speed 8 project.

But the key to the performance of the TS020 was its aero, and intelligent interpretation of the regulations. ‘I still think in the end [because] the road car was developed in parallel with the racecar [this] helped with homologation and that helped us to understand the rules, and see if they would follow this logic to allow certain things,’ said Litjens. ‘For the racecar you could put the fuel cell into the luggage compartment and that was how the regulation was written at that point. We had the most freedom from the aero. If you see where we had the coolers positioned, the inlet was part of the door. You open the door and you open also the inlet duct, but you could position everything nice so the front of the car was clean and free.’

The car went to Le Mans in 1998 but had gearbox issues. The Toyota team did get the repair time down from more than 10 minutes to just over six minutes during the 24-hour race, but there was no way that the car could win.

That honour fell to Porsche, but Toyota was back to have another go at the race in 1999.

‘It was a very heavy gearbox and almost impossible for the drivers to shift with it. After 20 hours no one wanted to drive the racecar’ 8 www.racecar-engineering.com RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT

For 1999, and with more testing than ever behind it and with the speed to match, the TS020 was the favourite to take victory, even against the might of Mercedes, Nissan, BMW and Audi. However, a suspension failure, an accident and a blown tyre accounted for the three-car effort. ‘During the night we struggled to keep the lap times up in the cooler temperatures but when the sun came up we were catching and we had a chance to win the race,’ remembers Litjens. ‘It was full attack.’

The TS030

Toyota withdrew from endurance racing after 1999 and focussed on its Formula 1 project, but by 2012 the decision had been taken for TMG to step back into endurance racing. Peugeot and Audi had worked with Toyota to develop the FIA World Endurance Championship technical formula and this marked the start of the full-on hybrid era. Peugeot had developed a hybrid version of its diesel-powered 908 HDI FAP and even built its own batteries for the programme in-house, while Audi used a mechanical flywheel for its R18. At the start of the year, however, with testing done and the teams preparing for the first race at Sebring, Peugeot abruptly pulled the plug on its Le Mans programme due to financial concerns within the parent company, and significant job losses, which made a racing programme unpalatable.

Toyota had been set for a year of development in 2012, but it was now suddenly

asked to step up to a full race programme and to start the championship. It complied, but this meant some compromises had to be made, for not only did it have to step up to a full race team effort before time, but it also missed several stages of the development cycle, which would have focussed on light-weighting.

The team missed the opening races but was ready to go at Le Mans, and even led the race overall. The car was powered by a 3.4-litre V8 normally aspirated engine, and the capacitor was developed by Nisshinbo. The front hybrid that was eventually used by the team was provided by Aisin AW, but that was not used in the first iteration of the car, which ran with only a rear system provided by DENSO. These two companies were OEM partners to Toyota and so both wanted the opportunity to develop their product within its racing programme.

The hybrid system, by regulation, was only able to store 1MJ, already double what Peugeot had developed, but the French manufacturer could see the writing on the wall and knew that these hybrid systems would only become more powerful and more expensive.

‘We developed the car to be able to test the front and rear system, but the regulations provided only for a small amount of hybrid energy,’ says Litjens. ‘Four-wheel-drive would have been better, but it would have been a massive weight, and [when] we started we were far away from the minimum weight because the capacitors were quite a bulky part.

For 1999, with more testing than ever behind it and with the speed to match, the TS020 was favourite to take victory

The TS020, better known as the GT-One, was designed entirely on CAD. The car was plagued with gearbox issues at Le Mans in 1998

In 1999 the TS020 was pitted against the might of Mercedes, BMW, Nissan and Audi at Le Mans, yet while it had the pace to win reliability issues and mishaps ruined Toyota’s race RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT www.racecar-engineering.com 9

LE MANS 2019 – TOYOTA ‘It was a new development and if you look at the technology at the time the super capacitor had a clear advantage over batteries, in what they could take, but the development [progressed] really quickly,’ Litjens adds. ‘The working range in the temperature was also key.’

Toyota was already racing super capacitors in Japan, and so it was logical to take the system and develop it using TMG’s impressive resources. The Japanese were also working with a brake by wire system that took care of the brake pressure feel for the driver whether the hybrid system was regenerating or not. The driver could not tell the difference and could brake as hard at the end of a race as the start as it also compensated for brake wear. ‘We had the brake by wire in the 030, but it was partly linked to what the Japanese had already started when they did this hybrid development and that fitted into our car,’ says Litjens. ‘Cooling had a drag penalty, but the weight was the big thing. I think it was 20 to 30kg, and the capacitor box itself was 65kg or 70kg, so it was a fair amount of weight, so we were always far over the weight.’

For the second generation 030 that raced in 2013, weight was shed at an alarming rate; more than 40kg came from the bodywork alone, a further 5kg from the tub. One of the key differences to the Audi, though, was that the Germans were able to switch off their hybrid system and be able to cope with running at Le Mans without it. For Toyota, that was not an option; the rear brakes were too small to cope without the hybrid aiding the brakes. ‘If you would have kept the same size of brakes

as standard you would not get the right temperature in it,’ remembers Litjens. ‘In F1 we had high wear because of the oxidation and you get friction wear, so if it got too cold the car can’t cope with that either, so we had to reduce the size and then we had to rely on the hybrid system to work. Everything goes hand in hand, and we could cope a few laps with it not working, but not any further.’

The TS040

The big leap in hybrid development came in 2014, when the amount of stored energy went into the stratosphere. From such a small system of 1MJ, which required a lot of cooling, suddenly the regulations would permit a jump to 8MJ. The organisers did not actually expect anyone to make such a leap, but in year one Toyota was close to being able to achieve it with the 040. The team opted, eventually, for 6MJ to the relief of Porsche as they could then commit to the same having faced cooling issues with their battery. The TS040 was powered by a 3.7-litre engine, based on the previous model but with a lengthened stroke to increase capacity. This engine was developed to run with the fuel flow meter, which changed the concept of the engine from power to efficiency.

Toyota and Porsche both had gasoline powered cars, while Audi ran diesel, and with the Brake Specific Fuel Consumption playing a key part in the new Equivalence of Technology, Audi guessed that its rivals were working together to their advantage. Litjens confirmed that the two ‘played the game, for sure’.

For the first time there was now a proper aero war between the three manufacturers.

Audi claimed that its tub was getting broken on kerbs, and so introduced a sprung floor to protect it for the 2014 season. Others realised that it was all about ride-height and therefore performance, but it was too late for them to copy it. Toyota produced a flexi rear wing, but that was less of a help to the drivers as they had no idea how much downforce they had through fast corners such as the Porsche Curves at Le Mans. Porsche had flexible rear bodywork that lowered at high speed, reducing drag.

However, the hybrid system remained at the forefront of development. Audi retained its flywheel system for the new regulations, Porsche continued to develop its batteries, while Toyota ploughed on with the super capacitors, which were fast to charge, and fast to drain. However, the capacitors were also expensive to produce, and cost as much to change as an engine – and changing them was a regular occurrence for the Toyota team. The fast-charging nature of the capacitors meant the technology should have had a performance advantage, but it was still a heavy system.

‘From the hybrid system the development was done to reduce the weight and from the chassis side we had to do another step to package everything,’ says Litjens. ‘In the end it was so tough and we were above the minimum weight, but if the performance gained outweighed the weight, then you still have to go for it. And we won the championship.’ However, victory at Le Mans still eluded Toyota.

The fuel flow meter changed the concept of the engine from power to efficiency, and this meant a big switch in thinking for its designers

The TS030 represented Toyota’s return to top level endurance racing; but it had to debut the car earlier than planned so as to fill a gap left by Peugeot’s withdrawal from the WEC 10 www.racecar-engineering.com RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT

The TS040 boasted a flexi rear wing at Le Mans in 2014, but the wing was quickly withdrawn as it was unpredictable. It won the WEC but not Le Mans

‘Where we had made 2.5s, the others had made five. It was as simple as that’

In 2015 a highly developed TS040 went well in testing but failed to deliver when it mattered and was off the pace at Le Mans

Then 2015 brought a reality check. The team developed the car so that it was ’80 per cent new’, according to technical director Pascal Vasselon, but the majority of the work had been done on the aerodynamics, with very little undertaken on the powertrain. The team found a big performance improvement and was confident, but it wasn’t until it reached the first race that the alarm bells started to ring. ‘We were limited in our resources and we raised our concerns,’ said Vasselon at the time.

‘The first time we put the car on the ground at Le Castellet [for testing], we were 2.5 seconds faster. Then we went to Aragon, 2.5s again.

It was a clear gain from the chassis. This was amazing. In F1, with stable regulations, we never saw such a clear gain. Usually you try to convince yourself that you are better but the lap times are not necessarily there. Here, it was a no-brainer. It was a big step and the drivers reported that the car was much better.

But the euphoria was not to last for long.

‘At Spa [for the first race], you see everything:

high speed, low speed, powertrain, and we saw that we were really behind,’ Vasselon adds.

‘Where we had made 2.5s, they others made five. It was as simple as that.’

The TS050

After Le Mans, in which Toyota just wasn’t competitive, the company promised its full support and for 2016 a whole new car was introduced. This was the TS050, which featured a new tub, a new hybrid system with the move to batteries, and a new engine, a 2.4-litre V6 twin turbo. The leap to 8MJ was a welcome one for the drivers, one reporting that he was a little giddy with the extra power. The engine was originally planned for 2017, but development was rapidly accelerated, with senior engineers switching to the twin turbo engine and taking over from the younger engineers who had started the programme and were developing the concept. An 800v battery system was also introduced for this season while Toyota also introduced FRIC suspension, and while this

combination was all a performance advantage, it meant that the team went to every race without a proper baseline from which to work.

‘We did a back to back performance test, to see if it brings something, because it costs some weight, but we have seen on a normal circuit some benefits from it,’ says Litjens of the FRIC system. ‘But if you do a one to one comparison it is very difficult. You have to run quite a lot with the car to extract the maximum from it. It was fun, though.’

The racecar came close to winning Le Mans, that elusive goal, but a link to the turbo broke in the final hour, leading to a sequence of shut downs that meant the car did not take the chequered flag, and was not classified. It was heart-breaking for the team.

Toyota returned in 2017, but this time there was no Audi, the German manufacturer announcing in October of 2016 that it would end its programme. Dieselgate hadn’t helped, with large fines on the horizon, and diesel had become a dirty word. In the background, a proposed rule change to go to 10MJ was rescinded, but by the time that decision was taken engineers in Japan had developed an exhaust energy recovery system and dyno tested it before it was scrapped.

Audi’s withdrawal left Toyota and Porsche alone in 2017, and again there was drama at Le Mans. The TS050 was quick, but various failures including clutch, electronics following a puncture, and a hybrid system failure cost Toyota the win. Porsche took its third victory on the bounce, and then retired from the discipline to focus on its new Formula E programme.

RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT www.racecar-engineering.com 11

LE MANS 2019 – TOYOTA Audi had left the WEC by 2017 but the TS050s suffered from a litany of reliability issues and Porsche won its third Le Mans in a row

The 2016 Le Mans 24 hours was heart-braking for Toyota, its TS050 coming to a halt while leading in the closing stages of the race

Toyota claimed victory with a distance that would have beaten Porsche in the previous two years The TS050 is set to race on for another season after this year’s Le Mans

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Incidentally, Toyota’s battery development meant that the temperature operating window was higher, and the compulsory air conditioning system was no longer required for the battery.

The battery therefore reverted to a more traditional water-cooling system.

Alone as a manufacturer for the ‘super season’ which ran from Spa in 2018 to Le Mans, 2019, Toyota had to find ways to race against the privateers. The team acknowledged that it would have to give up performance to allow the non-hybrids to compete, and reduced its maximum stint length, increased its weight and also reduced the amount of fuel that it carried, but the privateers were still not able to compete (see Racecar V29N7). The Le Mans win was of primary importance, and this was Toyota’s best chance to clinch it.

Victory at last

‘The only thing that really paid off was that instead of having the ultimate push for competition and performance, you can look more at Le Mans and reliability,’ says Litjens.

‘We changed the private testing completely, to thinking about what can go wrong. The performance we can keep at a good level and work on the other stuff.’ And with this approach, finally, Toyota broke the jinx, and claimed victory with a distance that would have beaten Porsche in the previous two years.

The car has now won every race of the 2018/19 season up to Le Mans 2019 on the road, but the results table shows that both cars were disqualified for damage to the floor at Silverstone. The TS050 has won the teams’ and drivers’ title, and the cars will race on into the 2019/20 season, the fifth year that the team has relied on this tried and trusted chassis.

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TECH DISCUSSION – POWER SOURCES

Electric shock Could the ongoing drive towards electrification at the expense of other powertrain solutions be seriously misguided? That was the question posed at the MIA Entertainment and Energy-Efficient Motorsport Conference on the eve of the Autosport International Show

By PROFESSOR STEVE SAPSFORD

W

ith much that is said in politics, we can never be sure we’re getting the complete picture.

The same is true of the UK government’s stampede towards full electric vehicles and the developing competition between cities across Europe to ban internal combustion engines as quickly as possible.

Are we sure this is the right approach? Are we sure we are getting all the facts? No doubt you will have been told that battery electric vehicles are zero emissions; indeed, it is even written on the back of some of them – surely that must be good. But is it true?

While the challenges we face are complex and interconnected, they fall into two main categories when we consider road transportation; greenhouse gas emissions (related to global warming, climate change etc.) and air quality (related to health). In this feature we will primarily focus on greenhouse

Might biofuel-ICE offer a better solution than EVs? IndyCar has been using a biofuel blend, E85 ethanol, for over a decade

Figure 1: Shell projections based on two alternative scenarios. Both predict us exceeding 40 gigatonnes of CO2 emissions per year between 2020 and 2025

One of the lowest overall carbon footprints is generated by a conventional internal combustion engine that burns a biofuel 14 www.racecar-engineering.com RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT

Figure 2: Green house gas emissions that are generated throughout a vehicle’s life cycle

The embedded carbon in the production of the electric vehicle is significantly higher than it is in the conventional vehicle gas (GHG) emissions and we will leave air quality for another time. However, we will touch on it briefly where it is relevant.

The energy/climate challenge and projected future energy scenarios suggest that we will face disruption of some form in the future. The global emissions of energy-related CO2 has been increasing steadily and this is only set to continue as the world gets more populated and the demand for energy increases further.

Shell has developed some projections of CO2 emissions based on two alternative scenarios; Oceans and Mountains (Figure 1 and box out). Both predict us exceeding 40Gt (gigatonnes) per year between 2020 and 2025.

If we then overlay the CO2 emissions which would enable the target maximum 2degC and

1.5degC temperature increases to be achieved, we see we have a significant disconnect. This will lead to some stark consequences; either environmental disruption if we continue along our present course; or economic disruption as we seek to force a change in trajectory.

The transport sector is committed to reducing its GHG emissions, but there is a genuine concern that the current legislative environment is forcing one particular solution to the exclusion of any of the alternatives, and this approach is the result of only looking at one small part of the picture.

When making our choices regarding the propulsion systems of our future vehicles we really need to consider the GHG emissions generated throughout the entire life-cycle of

Oceans deep, Mountains high

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he Mountains scenario is a world in which those occupying commanding advantage (at the top) generally work to create stability in ways that promote the persistence of the status quo. There is a steady, self-reinforcing, lock-in of incumbent power and institutions. This lock-in constrains the economic potential of some sectors of society, but enables established sectors aligned with market forces to unlock resources that require significant capital and new technology.

As for the less fortunate, the thinness of social safety nets is not completely offset by the growth in philanthropy, characterised by an eruption of foundations endowed by increasing numbers of billionaires.

The Oceans scenario paints a picture of a world in which competing interests and the diffusion of influence are met with a rising tide of accommodation. This trajectory is driven by a growing global population with increasing economic empowerment, and a growing recognition by the currently advantaged that their continued success requires compromise. Steady reform of economic and financial structures keeps pace with the development of fast-emerging nations and progressively unlocks the productivity of broader sectors in society. But volatility and multiple constituencies impede policy developments in other areas, so tight resources are unlocked primarily by market forces.

the vehicle (Figure 2). We need to account for the emissions associated with the extraction of the raw materials, processing them to be used in the production of the vehicle, using the vehicle (including the ‘fuel’ we use, be it electricity, liquid hydrocarbons or hydrogen) and, finally, the disposal and re-cycling of that vehicle; that is, a life cycle analysis (LCA).

So, what happens if we do a life cycle analysis for a passenger car with a number of alternative propulsion systems? Life cycle analysis is not easy. It involves a number of assumptions and so can never be definitive, but Figure 3 shows the estimated lifetime GHG emissions including the production, use and disposal of a typical passenger car expressed in kg CO2 equivalent (this means that the greenhouse effect of all the emissions – not all are CO2 – associated in the processes above are converted to the equivalent amount of CO2).

Most of the CO2 emissions for a conventional vehicle are released as we drive them, burning a predominantly fossil fuel. As we hybridise that vehicle, the embedded CO2 content increases as we add electric drive components such as motors, power electronics and (relatively small) batteries. The in-use CO2 decreases as we recover and use electrical energy to support the propulsion of the vehicle.

However, things change quite dramatically when we consider pure battery electric vehicles.

As you can see, the embedded carbon in the production of the vehicle is significantly higher than a conventional vehicle and this

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TECH DISCUSSION – POWER SOURCES

Figure 3: Estimated lifetime green house gas emissions from a selection of powertrain solutions

is dominated by the manufacture of the battery pack. The in-use CO2 emissions are, by contrast, significantly less, although the size of this contribution does depend massively on the carbon emissions associated with the generation of the electricity used.

In Figure 3 it has been assumed that the electricity can be generated at 200g CO2/kWh, which represents a healthy renewable content (UK currently ~300g/kWh). If the electricity was generated by burning coal that figure would be more like 1000g CO2/kWh, natural gas would be 500g CO2/kWh and the figure would look a lot worse. Conversely, if it was all from renewables, then that section would reduce to zero.

Hydrogen fuel cells offer an attractive alternative, but only if the hydrogen comes from renewable sources. Simply using methane (natural gas) as the source of hydrogen does not really help us much.

One of the lowest overall carbon footprints is generated by a conventional internal combustion engine that burns a biofuel and this is achieved by virtue of the fact that the production costs in terms of CO2 are low and the in-use fuel is made from re-cycled carbon.

One particular area of current interest is that surrounding synthetic fuels. These differ from biofuels mainly in their source of carbon. While both can be classed as renewable fuels, biofuels rely on organic sources of carbon such as wood chippings or waste agricultural products such as straw. Synthetic fuels, sometimes

Our politicians are not interested in talking about anything with an internal combustion engine called electrofuels or efuels, rely on CO2 for their carbon. Biofuels and synthetic fuels are of interest because they effectively re-cycle the CO2 that is released when they are burnt.

This technology is being promoted strongly in Germany, particularly by Audi and Bosch, as well as FuelsEurope and CONCAWE. However, there is still much work to be done on synthetic fuels. The manufacturing processes are not at scale and they are not currently efficient, requiring a lot of energy to produce, but the rewards are potentially huge: 1) We could refuel at the filling station in exactly the same way as we do now, removing all concerns around range anxiety. 2) We could use all the existing infrastructure both in terms of fuel distribution and IC engine/vehicle manufacture. 3) We could reduce the CO2 emissions of existing as well as new cars rather than relying on new electric vehicle sales to gradually reduce our CO2 emissions. 4) The same technology would benefit commercial vehicles as well, where liquid hydrocarbons are the only viable solution for long haul trucks.

The purpose of this article is to raise your awareness of alternative and complementary solutions for future propulsion systems. In

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making our choices regarding powertrain technology we really should be considering the overall impact of those choices, even if that analysis is only an estimate, to avoid unforeseen consequences. Whilst we appear to be on this somewhat blinkered, headlong rush towards full electrification, a more balanced and realistic view would be to acknowledge that there are a number of potential solutions, each with pros and cons according to their application.

Due to the pressures on air quality, it is entirely reasonable that full electric vehicles should be part of the portfolio, especially for city centres, but these are not the only solution.

But our politicians are not interested in talking about anything with an internal combustion engine in it and it is almost impossible to get investment for anything related to internal combustion engine development.

I hope this has demonstrated that hydrogen and renewable fuels offer great potential and should be part of the mix, but they do require their share of investment to develop the technology. If we can manage this, the potential impact on greenhouse gases could be significant; if not, we could be missing a huge opportunity and heading for disaster.

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TECHNOLOGY – HYDROGEN IN MOTORSPORT

On the gas In part one of a two part special Racecar explores the role of hydrogen fuel cells in motorsport, examining why they are needed, while also taking a look at some examples of prototype racecars that have already embraced this exciting technology

By RICARDO DIVILA

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alf a million years after the first signs of the use of fire by our ancestors, energy used for cooking is responsible for 0.5bn tonnes of CO2 emissions or 1.38 per cent of our yearly CO2 production. The rest is produced by all the other uses we have for energy. This is all a result of our ingenuity and inventiveness, but it also seems to bring a rather large downside along with it – damaging emissions and pollution.

On average, each person on the planet simply going about their normal business produces the equivalent of five tonnes of CO2 a year. The cycle of this seems to be increasing the average temperature of the environment we live and depend on.

In the 200 years from the start of the coal age to 1970, 420bn tonnes of greenhouse gases, mostly CO2 – that’s about 1200 times the weight of every person living on the planet right now – was produced through industrial activity, mostly the burning of fossil fuels. And still we are pumping CO2 into the air.

In order to limit global warming to less than 2degC, total emissions from global energy use across industry alone will have to be 50 to 80 per cent lower than they are now by 2050, and as much as 75 to 90 per cent lower if the rise in temperatures is to be capped at 1.5degC.

Energy bill

This will not be cheap. The estimate is that between 2016 and 2035 the annual cost of keeping the rise in temperature to 1.5degC would be about $2.4trn, which is roughly 2.5 per cent of world GDP. As a comparison, last year total energy investment was $1.6trn, mostly in coal, oil and gas.

Of course, the costs that will be incurred by us not doing anything about this would be in an order of magnitude that is much greater, 18 www.racecar-engineering.com RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT

The GreenGT LMPH2G is the most advanced hydrogen-powered racecar in the world and the flagship for the ACO’s H24 initiative

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TECHNOLOGY – HYDROGEN IN MOTORSPORT

Hydrogen’s potential has long been understood but only recently have road cars began to appear. The Riverside Rasa had been developed by former racecar designer Hugo Spowers

and difficult to quantify, as the collapse of the biosphere will lead us into unknown territory.

The increasingly ominous costs, in both a wide and narrow sense, of all this have led to a search for other methods of energy production.

The obvious solution is replacing fossil fuels with new renewable energies, such as solar, wind and wave power (direct harvesting), and also other solutions such as biofuels.

As for the latter, so-called energy crops compete with the food industry for land, and their cultivation also produces greenhouse gases, so it’s not the best answer.

And remember, electricity, which is now touted as a way forward, will only truly be a clean solution when the generation of the electricity itself is clean, and this is certainly not the case today. Too much of it is still produced by fossil fuel-fed power stations.

Renewables

Now, though, it is also finally becoming affordable to harness renewable energies on a large scale. However, in solving the environmental issues from fossil fuels with renewables, new challenges arise.

Investment in renewables has been twice as much for coal, gas, oil and nuclear combined last year, while sales of electric vehicles are increasing rapidly. It took 17 months, from mid-2014 to 2016, for the global number of passenger EVs to go from one million to two million. It took just six months in 2018 for them to increase from three million to four million.

But decarbonising parts of the economy where electricity and lithium-ion batteries are difficult to use – heavy transport, heating and industry – will be hard. In 2014, these ‘hard-to-

Electricity will only truly be a clean solution when the generation of it itself is clean, and this is certainly not the case today abate’ sectors produced about 15bn tonnes of CO2, or 41 per cent of the total, compared with 13.6bn tonnes for the entire power sector. The biggest industrial emitters of all, by the way, are cement, steel and chemicals.

Electricity has been a much heralded replacement for internal combustion engines (ICE), but it is a matter of transmitting power supplied by fossil fuels, hydro-power, solar

panels and nuclear generators. For free roaming transport it could power electric motors by induction, but the main form is by battery, where energy is stored in a chemical process.

The production of electricity itself can also be a major polluter, as we’ve already pointed out, but in its present utilisation in batteries for town electric cars, at least it shifts pollution away from cities. Solid-state batteries

Post impressions

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he technology being developed by QUICK SPEC: Maxity H2 GreenGT for the H2 racer was also used in a parallel project for a utility vehicle Performance for the Post office in Dole, Jura, in France, Average autonomy up to 200km (100km from the batteries); maximum speed of 90km/h where a truck called Maxity H2 was put into Motor service for one year, serving as a test for Asynchronous electric motor: 400V / 47kW (robotic gearbox) electric-hydrogen propulsion.

Batteries The vehicle was equipped with a 20kW On-board energy: 42kWh lithium-ion technology / iron phosphate fuel cell and a lithium-ion battery to power the (Valence Technology); four battery packs with a total weight of engine, and it had a range of about 200km.

400kg. Full recharge time including battery equalisation phase: seven hours. On-board charger allowing charging on a single Its battery could be recharged in six hours. three-phase power supply The fuel cell installed on the Maxity actually Hydrogen Fuel cell also used the heat that it released to warm up On-board energy: 45kWh; hydrogen cell: 20kW. Two 75-litre the passenger compartment, to avoid using hydrogen tanks, allowing storage of 4kg of H2 at 350bar pressure. the energy of the battery, and therefore to Total weight of the hydrogen unit: 300kg preserve the autonomy of the test.

Commissioned in February 2015, the truck had, a year later, travelled 10,000km in 150 days. The fuel cell on this vehicle proved that the electric-hydrogen alternative not only gives a much higher efficiency than just electric, and is emission free, but is also applicable to many applications requiring high-power motors.

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Hydrogen is the most abundant element, it is 90 per cent of the mass of the universe are likely to be the game changers of future battery chemistries, as they render 2.5 times higher density than lithium-ion. In short then, electricity stored in batteries has an advantage as a power store, but has a limited range and slow re-charging, despite the continuous work being done with this technology.

Traffic report

Right now, in transport at least, the current consensus is that it will be a hybrid mixture of all these technologies for some time, considering the time needed to replace all the vehicles on the world’s roads today (cars, trucks and buses), which could rise to 2.8bn by 2036, on current growth rates, and near 5bn by 2050. To put things in perspective, the world’s fleet was 342m in 1976, 670m in 1996 and 1.4bn today, effectively doubling every 20 years. China, all by itself, has a fleet of 320m, the equivalent of the whole world in 1976, and is growing at the rate of 28m a year.

In comparison, the world’s electric vehicle fleet is around 4.28m, but that includes full electric, hybrid and plug in hybrid. From the 1.6m cars sold this year EVs have a market potential of about 25m units that will be sold by 2025. A long way to go then.

Hydrogen

Hydrogen fuel cells could solve some of the problems highlighted above (see box to the right for the basics). When these are combined with electrical motors it closes the circle, a hybrid cycle combining the individual advantages, with a longer range and easy refuelling. But hydrogen also has to be produced and transported, which brings in issues of an infrastructure to be built.

Hydrocarbons have that already, built up over the last hundred years. Hydrogen will need a concentrated effort in a short period to do so.

But we are seeing the beginning of it.

Hydrogen is the most abundant element of all, 90 per cent of the mass of the universe.

Three-quarters of the sun is made of hydrogen.

It is the element with the smallest atom in the universe. It exists as a gas and has an energy density higher than hydrocarbons. It could be the most promising fuel source because it is the best complement to mass electrification, and could also be used in heavy transport, heating and industry. None of the technologies involved

A fuel cell primer

A

fuel cell is an electrochemical cell that converts the chemical energy from a fuel into electricity through the electrochemical reaction of hydrogen fuel with oxygen. A fuel cell is different from batteries in that it uses fuel and oxygen (usually from air) to sustain the chemical reaction; in a battery the chemical energy comes from chemicals already present in the battery. So fuel cells produce electricity continuously when the fuel and oxygen are supplied.

A working fuel cell was first demonstrated back in 1839 by Sir William Grove, but the concept had been postulated in the early 19th Century by a number of scientists, including Humphry Davy and Christian Friedrich Schonbein. But it is Grove, a chemist, physicist and lawyer, who is generally credited with inventing the fuel cell.

The first truly workable fuel cell was not developed until 1959. Initially it was used in NASA’s space programme, but then interest waned until the 1990s when new research and development then led to better prospects for commercialisation.

Then the need for renewable energy sparked huge technological progress in the last decade.

Since then, fuel cells have been used in many applications, including primary and back-up power for commercial, industrial and residential buildings and in remote or inaccessible areas.

Fuel cells are also used to power fuel cell vehicles, including forklifts, automobiles, buses, boats, motorcycles and submarines.

How fuel cells work A fuel cell converts chemical potential energy – which is energy stored in molecular bonds – into electrical energy. A PEM (proton exchange membrane) cell uses hydrogen and oxygen as fuel.

Since oxygen is available in the atmosphere, we only need to supply the fuel cell with hydrogen, which can come from an electrolysis process (alkaline electrolysis or PEM electrolysis). The products of the reaction in the cell are water, electricity, and heat. This is a big improvement over ICE, coal burning power plants, and nuclear power plants, all of which produce harmful by-products.

By converting chemical potential energy directly into electrical energy, fuel cells are inherently more efficient than combustion engines, which must first convert chemical potential energy into heat, and then into mechanical work. Direct emissions from a fuel cell vehicle are just water and a little heat. This is a huge improvement over the internal combustion engine’s plethora of greenhouse gases.

Fuel cells have no moving parts, and are thus also more reliable than traditional combustion engines, while hydrogen can be produced in an environmentally friendly manner.

While there are a wide variety of fuel cells what they all have in common is an anode, a cathode, and an electrolyte that allows positively charged hydrogen ions (protons) to move between the two sides of the fuel cell. At the anode, a catalyst causes the fuel to undergo oxidation reactions that generate protons (positively charged hydrogen ions) and electrons. The protons flow from the anode to the cathode through the electrolyte after the reaction. At the very same time, electrons are drawn from the anode to the cathode through an external circuit, producing direct current electricity. At the cathode, another catalyst causes hydrogen ions, electrons, and oxygen to react, forming water. And the best thing of all is that water vapour is then the only emission.

GreenGT built a series of electric cars, including the 200kW, to hone batteries and motors before it developed its fuel cells RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT www.racecar-engineering.com 21

TECHNOLOGY – HYDROGEN IN MOTORSPORT

The first hydrogen fuel cellmotivated racecar was GreenGT’s H2, an experimental prototype that was unveiled back in 2012

Battery storage may feel like a headline act, but ultimately it will be playing a secondary role to hydrogen are new and the more they are used the more their costs fall, which is not the case with fossil fuels, giving the incentive to use them across as many industries as possible.

But to achieve net-zero CO2 emissions, global hydrogen production needs to rise from about 60m tonnes a year now to 500m-700m tonnes by 2050, an ambitious tenfold increase in 30 years. The interest in hydrogen is growing fast, though. Membership of the Hydrogen Council, a forum made up of global chemical, car and oil companies started in 2017, has quadrupled in 18 months. Battery storage may feel like a headline act in the transition, but ultimately it will play a secondary role to hydrogen.

Racing green

But where does motorsport come in? Well, a major flaw in motorsport in relation to the public is that it is mainly visible through F1, but the image is of a glamorous lifestyle with hundreds of millions of euros being spent to field two cars for a year’s campaign in a profligate waste of resources – a rich man’s sport burning up the planet’s resources. The people

Aston Martin has also dabbled with hydrogen tech; this is its bi-fuel (hydrogen and petrol) Rapide at the Nurburgring in 2013

involved in the sport know otherwise, possibly the fans do also, but the message needs to be redefined for the sport to avoid being seen on the wrong side of history by the public.

The consensus on climate change and other problems related to emissions are increasingly recognised by the younger population. Rear guard action by the entrenched industries and beneficiaries of the status quo are akin to the dinosaurs, unaware of their impending extinction, just looking at the short term.

The trend increasingly seen in most forms of racing is ageing spectators following the sport that attracted them in their youth, without the renewal of new cohorts that will be in the majority in the following decades.

Incorporating KERS in F1 and LMP1 cars started showcasing the technology, but it

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still needs to be emphasised more and be more evident. Formula E, despite being still in its crawling stage, with low-powered cars in comparison to other categories, has proven a magnet for manufacturers presenting their clean image to a younger and new public.

Case study

So maybe this is where hydrogen might step in?

Here’s an example of the work being done by GreenGT with a fuel cell powered car running on hydrogen, giving the stages gone through to arrive at the latest version, presented by the ACO under the banner of Mission H24.

The project is mainly a presentation via racing to introduce the concept to the public, who might have little idea of the basics of chemistry or energy, and then developing

Putting a hydrogen car on the grid gives a direct comparison to the current tech, while at the same time developing future alternatives the concept in competition. Putting a car on the grid gives a direct comparison to what is the current paradigm, and at the same time develops the future alternatives.

The car is in its developmental stage, which is aimed at finding and validating the solutions and technologies that have to be created to produce a viable racing car to replace the soon to be obsolescent ICE paradigm.

Gas guzzler

The performance of the Hydrogen racer is to be directly compared to a current GT racecar, which thus sets the size, power and weight parameters to be achieved. To be able to be competitive new rules have to be written to accept it and to take into account the characteristics of the technology, this is being done by the ACO to blend in with the current cars, much like the EoT used for LMP1s running different fuels and kinetic recovery systems in previous years.

GreenGT has developed the technology through a series of prototypes, including the 2009 GreenGT 200kW, a carbon chassis with two linear synchronous 100kW three-phase motors. The power supply was lithium-ion packs charged by Flexcell thin solar panels.

The company was also commissioned to produce the powertrain for the Citroen Volt 100 per cent electric propulsion concept car in 2010, with two electric synchronous motors giving

a total of 220.5kW (around 300bhp) at the rear wheels. Energy storage was in two lithium-ion batteries (140kg each), with 31kWh capacities, weighing 1150kg all up, and it had a top speed of 260km/h, zero to 100km/h in under five seconds and a range of 15 minutes on track.

Powering up

The next step was to increase the power with the 2011 GreenGT 300kW, which further developed the electrical powertrain powered by batteries; it had two synchronous threephase motors of 150kW. The battery had a 12 to 17 minutes range at 300kW discharge, 15 to 20 minutes at 250kW, and 18 to 22 minutes at 200kW, depending on the circuit.

Having developed the reliability on the electric side (motors, batteries, control system) the fuel cell part was integrated to complete

The technologies involved are not new and the more they are used the more their costs will fall

the concept. The first hydrogen powered fuel cell competition car was in 2012, the H2, a car which featured two experimental three-phase permanent magnet synchronous Brusa motors. (two x 200kW, or 544bhp).

The fuel cell was a PEM 18-stack with a linear power of 340kW and an experimental high temperature membrane. It also boasted specific aviation-type lightweight elements; elements optimised for a minimum target of 500 hours; the ability to operate the fuel cell without a buffer battery, and an electronic control system specially designed for battery-free operation.

Refuelling was a hot-swap concept, where the two lateral reservoirs were exchanged, all connections being quick-release dry-breaks.

The hard cell

Development of the fuel cell brought the initial 400kg for 300kW down to 133kg for 250kW and finally less than 100 for 200kW each. It is an ongoing process, bringing the performance up and the weight down, the latest car is 1420kg, but is targeted to arrive at 1100kg with more work. Likewise, the motors have evolved from an initial 140kg down to 107kg over three and a half years of development. The optimisation of all items brings synergistic gains overall.

The second iteration of the project produced a car that would compete on a equivalency with a GT, the LMPH2G, using a carbon chassis

The GreenGT LMPH2G packs an electric-hydrogen four-stack fuel cell with polymer electrolyte membrane which produces a constant 250kW (335bhp) through four electric motors RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT www.racecar-engineering.com 23

TECHNOLOGY – HYDROGEN IN MOTORSPORT GreenGT LMPH2G Key to diagram 1. Electric motors Four electric motors on the rear wheels (two on each) provide propulsion.

2. Hydrogen reservoirs The dihydrogen (H2) is stored in three pressurised (700bar) carbon filament tanks used to fuel the cell.

The first two are placed either side of the cockpit and the third just behind the driver.

3. Hydrogen fuel cell Comprises four stacks, at the core of which molecules of dihydrogen (H2, stored in the tanks) and oxygen atoms combine to form water molecules (H2O). This reaction produces heat, and electricity, which powers the car’s electric motors.

4. The stack A layered pile of 230 cells, bipolar plates and hydrogen porous membranes.

5. Air Intake The ambient air used to produce the reaction within the stacks enters through this vent. It is filtered, propelled towards the compressor, then the humidifier, before entering the stacks.

6. Buffer batteries Excess electricity produced by the hydrogen fuel cell and by the KERS system (when braking) feeds into high-performance cells. The driver can therefore double the car’s acceleration potential (250 to 480kW, the equivalent of 653bhp).

9. Humidifier Humidified air improves the interaction between oxygen atoms and dihydrogen molecules. The humidifier ensures the level of humidity of the air injected in the stacks remains constant.

10. Radiators and cooling system

7. Transmission A special, clutch-less single-speed gearbox manages the rear wheels independently and is designed to reduce grinding.

11. Exhaust The only emission produced by the Green GT LMPH2G is water (H2O). Steam escapes through four vents (one per stack) to the rear of the car, in the middle of the aerodynamic diffuser.

8. Compressor This compresses and accelerates the air that enters via the vent (up to 300g per second). It operates at up to 100,000 revolutions per minute. The modulation of the airflow injected in the stacks alters the reaction and therefore determines the amount of electric power produced.

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8

11 1 3 6

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with a rear steel frame, and the classic double wishbone pushrod suspension and carbon brakes. The powertrain consists of a GreenGT electric-hydrogen four-stack fuel cell with polymer electrolyte membrane producing a constant 250kW (335bhp) through four electric motors (two per rear wheel). Maximum output 480kW at 13,000 revs (653bhp) and the 2.4kWh buffer battery delivers an additional 250kW for 20 seconds. The hydrogen is stored in three pressurised tanks (see the operating diagram above) at 700bar pressure.

The weight of the LMPH2G is 1420kg in working order (front 39.8 per cent and rear 60.2 per cent). The weight increase when refuelled

7 10

4 9

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is just 8.6kg, and this is one of the paradigms that racing will have to digest, being used to hydrocarbons, where filling a 63-litre tank increases the all-up weight by 43.6kg.

Safety advances

A good example of the changing constraints in the design is given by the evolution of safety by the regulating laws. The previous 2.2 safety factor for pressurised hydrogen containers (that is, a 700bar hydrogen container must be rated at 1540bar pressure) is being re-regulated at a factor of two, as a result of the knowledge amassed in operating and manufacturing them.

This allows the container weight to be reduced.

The buffer battery kinetic energy recovery system (KERS) charges a 750V battery of 2.4kWh capacity. Battery design evolution is another field where the mass is being constantly reduced, all of which makes this a more and more viable option for motorsport.

Refuelling with pressurised tanks could be further developed by the use of liquid hydrogen and hoses. As liquid hydrogen storage entails thermal insulation and high pressures, this is a later step, but the advantages of using this fuelling method are extensive. Thus this will be examined in detail in the next instalment in this series (page 26), where we will cover this second car in much more detail.

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TECHNOLOGY – HYDROGEN IN MOTORSPORT

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The hard cell

In part two of our investigation into the use of hydrogen fuel cells in motorsport Racecar explores the challenges facing the development of the technology with an in-depth case study of the ground-breaking LMPH2G sports prototype

By RICARDO DIVILA

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TECHNOLOGY – HYDROGEN IN MOTORSPORT

GreenGT’s LMPH2G has been built to demonstrate the possibilities of hydrogen fuel cells in racecars. It can reach 100km/h in 3.4 seconds and has a max speed of over 300km/h

I

n part one of this mini series we examined the potential for hydrogen fuel cell racecars. But now it’s time to turn our attention to what has to be the most high-profile of existing projects. Here we will look at the design challenges inherent in a change of motive power from the classic internal combustion engine to hydrogen, and how GreenGT, the maker of the revolutionary LMPH2G, has overcome many of them.

But first we need to back-pedal a little to put the LMPH2G into some sort of context. The first fuel cell project attempted by GreenGT was the H2, a proof of concept car. This was presented as a potential Garage 56 contender, the ACO’s slot for allowing new technology to be demonstrated at Le Mans, not constrained by the regulations so as to enable revolutionary concepts to run at the race.

The powertrain for the GreenGT H2 was two electric motors powered by electricity generated in a PME hydrogen fuel cell, the pressurised hydrogen being stored in carbon fibre cylinders that hung on the sides of the

car. These reservoirs could be hot-swapped via a quick-connect dry-break coupling.

The development work carried out on the original GreenGT H2 racecar enabled various new technology components to be validated, while also discovering the operational problems attached to the concept.

Gassed up

The powertrain layout for the second, closed cockpit, version of the car – the LMPH2G we are examining here – maintained the rear-wheel drive layout of the H2, with the centrally positioned fuel cell carried in a carbon container and effectively replacing the conventional engine as a stressed member.

There was also a third reservoir added to the layout, so there were two placed on the sides and one behind the cockpit.

Compared to more conventional racecars, the whole packaging ends up more complex, because of the new technology parts, plus accessibility and running requirements. Yet the design of the prototype still had to determine

The centrally positioned fuel cell, carried in a carbon container, effectively replaces the conventional engine as a stressed member 28 www.racecar-engineering.com RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT

TECH SPEC: LMPH2G Chassis Carbon LMP chassis with steel sub-frame; double wishbone pushrod suspension; carbon brakes Power unit GreenGT electric-hydrogen powertrain (4-stack fuel-cell with polymer electrolyte membrane) producing a constant 250kW; four electric motors (two for each rear wheel); maximum output of 480kW at 13,000rpm (653bhp); 2.4kWh KERS delivering 250kW for 20 seconds Performance Maximum speed: +300km/h; 0–100km/h in 3.4 seconds; 400 metres from standing start in 11 seconds. Range is equivalent to other racecars with comparable performance, the current refuelling time is three minutes. The emissions into the atmosphere is water vapour only Transmission Direct drive to rear wheels (ratio:1:6.3); no gearbox, no clutch, no mechanical differential; electronic torque management system Hydrogen storage Fuel tank capacity is 8.6kg of hydrogen at a storage pressure of 700bar Wheels and tyres Front: 30/68-18 Michelin Pilot Sport GT(hub12X18); Rear31/71-18 Michelin Pilot Sport GT(hub13X18) Dimensions Length: 4710mm; height: 1070mm; width: 1970mm; wheelbase: 2970mm; front overhang: 1000mm; rear overhang: 740mm Weight 1420kg in working order (front: 39.8 per cent, rear: 60.2 per cent). Weight variation at refuel: 8.6kg

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TECHNOLOGY – HYDROGEN IN MOTORSPORT The original GreenGT hydrogen racecar was the H2, which broke cover in 2012. This was an experimental prototype that packed two electric motors and a PME fuel cell

the systems layout considered as a racecar, complying with the safety and dimensional regulations, to optimise the use in a racing environment. For an efficient cost process the use of as many existing elements as possible was included in the design brief. As the systems are developed, more bespoke items will be fitted as the technology matures.

KERS and effect

For this second iteration of the concept, and to improve the energy efficiency, a Kinetic Energy Recovery System (KERS) was added to the car, harvesting part of the energy required to retard the car through the rear wheels using the electric motor functioning as an alternator and storing it in a buffer battery, to be deployed in acceleration as required. Considering that all the power applied to the wheels is electric through the two motors per wheel, this also enables traction control and torque vectoring to be electronically controlled. This had been explored on the first car and has now been further developed on the LMPH2G. Through GreenGTs proprietary software, the aspects mentioned above also open up a new way of contributing to the car dynamics, maybe by dialling in understeer or oversteer simply by applying more torque to one of the motor pairs on a single wheel. This is easily

Under the skin of the LMPH2G. Two electric motors can be seen here (there are two more on the other side). The orange power lines go from the inverter to the motors

Caption

30 www.racecar-engineering.com RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT

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TECHNOLOGY – HYDROGEN IN MOTORSPORT

The monocoque was designed to LMP3 internal dimensions but it also had to carry the three hydrogen cylinders – these were originally developed for use in a fuel cell truck

Despite having efficiencies that are higher than internal combustion engines, heat rejection from fuel cells remains a challenge done as it’s not dependent on any mechanical or hydraulic mechanism, but just by controlling energy deployed to each of the wheels.

Stabilising braking into corners can also be envisaged, by harvesting more on one side. This is similar to fiddle brakes on trial cars, or the system used in Formula 1 where the steering lock and brake pressure on the individual inner wheel or outer wheel calipers were tied together. This was banned in F1.

While we’re in this area, the suspension design is the classic double wishbone, pushrod actuated through rockers with coil spring over coaxial damper units, roll couple being controlled by transverse anti-roll bars.

Gas tanks

The monocoque was designed to the current LMP3 internal dimensions, and this tub had to house the three hydrogen containers, which are an off the shelf carbon cylinder (as used on the prototype Renault truck that’s powered by GreenGT’s fuel cell and motor).

The 700bar containers have a cylindrical shape for better pressure resistance, but they present packaging challenges compared to the any-shape fuel bags that are conventionally used. Because of the current safety regulations for pressure vessels these end up weighing

Table 1: Drag and downforce contributions on a conventional racecar Component (positive values lift)

Cl

Front splitter Front tyres Flat bottom Rear diffuser Rear wing Rear wheel Bodywork Internal drag (radiators, flow through engine compartment) around 100kg, when they are made from carbon. But they do have an advantage of being completely self contained and easily removed for maintenance or repair work on the racecar, as does the buffer battery, placed behind the driver bulkhead on what would be the conventional fuel bag housing.

The cooling system on any racecar is one of the fundamental parts of the aero package, as the sheer amount of surface exposed to flowing air needed to dissipate the heat produced by the power system entails a considerable amount of drag, and the passthrough requirements will give problems in housing the radiators and in having space for the ducting, while the exit of the air must

32 www.racecar-engineering.com RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT

-43% 1% -39% -17% -23% 0% 19% 1%

Cd

L/D

19% 3% 9% 13% 17% 8% 11% 20%

-2.26 0.33 -4.33 -1.31 -1.35 0.00 1.73 0.05

produce a minimum disturbance of the car’s aero package. If we take a conventional racecar running today we can split the drag/downforce contributions of the major individual components (see Table 1).

Core issues

Table 1 shows that the cooling requirement ends up being the major individual drag contributor in any car and this is mainly due to the pressure drop through the core. For an ICE it is a quite direct result of the power produced.

As a rule of thumb, considering average efficiency we can say that for each 100kW of energy from fuel, 30kW will go to drive the car, around 35kW will be lost as heat to exhaust,

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TECHNOLOGY – HYDROGEN IN MOTORSPORT

Total pressure plot. The aerodynamic design approach has been conventional so far

Rear diffuser and oil cooler exit flows. Efficient cooling is still needed on fuel cell cars

It’s expected that the aero approach will change as the car is further developed

Top and bottom pressure coefficients were plotted on the baseline body shape, which corresponds to the FIA’s regulations for the dimensions of a sports prototype racecar

and about 28kW will be dissipated by the radiators. Major gains in the development of internal combustion engines have been made in improving this ratio. Current F1 engines have attained values of 48 per cent, a direct result of allocating a fixed amount of fuel for the race.

In the example above the power going to the wheel will be, then, 48kW. This an aspect of racing which the public hasn’t appreciated as it should, half again as much power added for the same fuel energy available.

A fuel cell operates on a different principle.

But the fuel cell, while producing energy by the chemical process of combining oxygen (from ambient air which contains oxygen, nitrogen,

Water vapour rather than exhaust gases will affect the aero at the rear of the car

Future car layouts could differ when designed as a complete unit to suit the new technology argon and other trace elements) also produces heat as a by-product of all this, so it will also have to be cooled, as will the batteries, which produce heat as a by-product of the chemical reaction when returning electricity when drawn upon. The fuel cell optimum operating temperature is about 80degC. The efficiency of a radiator is directly related to the temperature delta between the fluid being cooled (in most cases water or oil) and the ambient air

temperatures – heat exchangers such as water/oil or air/air found on supercharged engines work to the same rules.

Despite having efficiencies higher than those of internal combustion engines, the heat rejection from fuel cells remains a challenge due to the lower operating temperatures and the reduced exhaust heat flow.

Aerodynamics was examined in CFD and the layout was determined with the need

Table 2: Hydrogen compared with other fuels Property

Molecular weight (g/mol) Density (kg/m3 at 20degC) Normal boiling point (degC) Flash point (degC) Flammability lim. in air (Vol %) CO2 production/energy unit Auto-ignition temp in air (degC) Higher heating value (MJ/kg) Lower heating Value (MJ/kg)

Hydrogen

2.016 0.08375 -252.8 < -253 4.0 - 75.0 0 585 142 120

Methane

16.043 0.6682 -161.5 -188 5.0 - 15.0 1 540 55.5 50

Methanol

32.04 791 64.5 11 6.7 - 36.0 1.5 385 22.9 20.1

34 www.racecar-engineering.com RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT

Ethanol

46.063 789 78.5 13 3.3 - 19 N/A 423 29.8 27

Propane

Gasoline

44.1 1.865 -42.1 -104 2.1 - 10.1 N/A 490 50.2 46.3

~107.000 751 27 - 225 -43 1.0 - 7.6 1.8 230 - 480 47.3 44

Impact tests were modelled with special attention being given to the reservoirs, reservoir attachments and fuel cell. Many safety requirements are in the process of being formulated

Hydrogen has the lowest explosive energy per unit of any stored fuel

The monocoque mesh for FEA analysis. A recess for one of the hydrogen cylinders is clear on the flank of the tub in this image

to house two of the three cylinders on the monocoque sides. This in turn meant the main fuel cell coolers had to be fitted in the nose of the car, the usual side radiators being difficult to house. Also, given the placing of other components such as the humidifier, the charger for air supply to the cell and the ancillaries in the engine bay, through-flow there is quite compromised. The exit flow on the side is a corollary of that.

Further iteration of the design will be implemented as the prototype testing refines the systems, with particular attention being given to the aerodynamics, and the complete layout will evolve as the operation of the car

Table 3: Hydrogen volumetric energy density comparison with petrol MJ/m3 H2 at 350bar H2 at 700bar H2 as liquid Petrol

4500 5000 9200 32000

Table 4: Hydrogen mass energy density comparison with petrol MJ/kg H2 Petrol

120 40

validates the concepts. Currently it is close to car layouts developed for ICE powertrains, but future layouts could differ when designed as a complete unit to suit the new technology.

Safety issues

The FIA has a series of rules established to ensure the operational safety of ICE engines, lessons having been learnt over the years as to the intrinsic dangers of the systems, such as flammability, toxicity and impact resistance.

When hybrids, with electric batteries or kinetic energy storage systems via flywheels, were introduced, a whole new set of safety parameters had to be specified for their use.

Fuel cell cars are now going through the same process. GreenGT is working with the FIA and the ACO to determine which will be the future rules for the safe operation in a racing environment of the vehicle. New regulations are being drawn up, with GreenGT

investigating all the safety aspects of the systems being developed.

The structural requirements and the parameters for the electric motors and buffer battery are covered by the previously defined regulations, but the reservoirs, fuel cell and refuelling procedures are all new territory and these need to be defined.

The chassis must respect the crash test regulations, much the same as conventional racecars, but with particular attention being given to the reservoirs, reservoir attachments and the fuel cell itself. FEA analysis was done with several configurations, as a way of preparing the parameters of the crash tests to be executed on a fully assembled monocoque for homologation. Similarly, impact tests were modelled and the structure was designed to suit the requirements.

Then, of course, there are the safety considerations that arise from using hydrogen

Investigations into the Hindenburg disaster proved that the aluminium paint that coated the airship started the fire, not the hydrogen RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT www.racecar-engineering.com 35

TECHNOLOGY – HYDROGEN IN MOTORSPORT as a fuel. The reputation of hydrogen has been unfairly tainted by the Hindenburg disaster in 1937 – when a German passenger airship burst into flames while attempting to dock with its mooring mast in New Jersey. Yet investigations into the Hindenburg incident proved that the aluminium paint that coated the ship started the fire, not the hydrogen.

Actually, hydrogen is a safe gas. Since it is a small molecule, it has a tendency to escape through small openings more easily than other fuels. Hydrogen can leak through holes or joints of low-pressure fuel lines 1.2 to 2.8 times faster than natural gas. But natural gas has an energy density three times greater than hydrogen, so a natural gas leak results in a greater energy release than a hydrogen leak.

Since hydrogen is lighter and more diffusive than gasoline, propane, or natural gas, it disperses much more quickly. If an explosion occurred, hydrogen has the lowest explosive energy per unit of stored fuel.

The LMPH2G in the pits at Spa. The manual for operating a hydrogen fuel cell racecar is still being written

Low risk fuel

Yet there are many mistaken preconceptions about hydrogen, just one of which is that it is a dangerous gas. Discovered by Henry Cavendish in 1776, hydrogen and its properties are now well known and today the risks have been pinpointed and contained by safety measures and standards. Fire prevention professionals now consider hydrogen safer than any other fuel used in the open air. It is understood that the storage tanks meet the strictest requirements in terms of resistance.

As an example, at the LMPH2G presentation at Spa the refuelling pit stop operation was completed by an operator wearing normal clothes – there was no need for overalls or helmet, they simply connected the valve.

Hydrogen (gas) is contained in sealed tanks at 700bar pressure. The tank’s seals and contents are systematically checked before the hydrogen is injected. Today there is an array of safety standards, which are applied across the globe. In Paris, several service stations supply a fleet of hydrogen-powered taxis. It is, then, a very well-developed technology from a safety standpoint.

Liquid hydrogen

But that’s hydrogen as a gas. Future development could see the introduction of liquid hydrogen as a fuel, which will speed up refuelling and bring several other advantages.

To exist as a liquid, H2 must be cooled below hydrogen’s critical point of 33K (-240degC).

However, for hydrogen to be in a liquid state without boiling at atmospheric pressure it needs to be cooled to 20.28K (−252.87degC).

This will bring several design challenges, such as structural integrity for the reservoirs at cryogenic temperatures and isolation from any heat that would increase the pressure in the tank. But the current vehicle is proof of concept

The GreenGT H2 Speed hydrogen road car is a concept by Pininfarina that was unveiled at the Geneva show

Future development could see the introduction of liquid hydrogen as fuel, which will speed up refuelling and bring several other advantages and most car manufacturers have been developing cars for road use on the pressurised 700bar reservoir parameter, and it has been designed to those same values.

As liquid hydrogen expands into a gas the energy to vaporise the liquid would be integrated with the cooling system, reducing the surface area required, as heat from the fuel cell and batteries would be used for this.

Gas station

As to working with the car, discussing the requirements with crew members who were experienced in current ICE cars but have come in to the team, the most striking thing was the steep learning curve of getting to grips with all

36 www.racecar-engineering.com RACECAR ENGINEERING LE MANS 2019 SUPPLEMENT

the procedures required for safe, efficient use at the race track. Safety procedures needed to operate an ICE car with a hybrid battery based KERS system were known, but when the start-up procedures, operational temperature requirements and electronic management of the system is added on, it adds up to a highly technical method of working.

As the car continues to test the operating manual grows daily, as the systems and evolutions of units are explored. It is a complex combination of several distinct technologies, still in its early stages, but will be made easier as the knowledge of use increases. The lessons learned will eventually be incorporated in the every day car, sooner than you think.

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