4Focus ROB MARSHALL TAKES A LOOK AT NEW CAR TECHNICAL INNOVATIONS
TESLA: MEDIA CONTROL UNIT (PRE-2021 MODELS PICTURED) Last year, TRL (known formerly as the Transportation Research Laboratory) found that negotiating touchscreen displays while driving is more distracting then making a call on a handheld mobile phone. Even so, manufacturers refuse to fall out of love with them. Tesla is a notable touch-screen pioneer, not only in terms of impressive screen sizes but it also claimed recently that its updated Model S and X cars will use their Media Control Units to replace even more physical controls, including the transmission selector and direction indicator stalks. It sounds amazing. Yet, it makes the consequences of a failed touchscreen more than an inconvenience and the situation appears to be far from unusual. In North America, for example, Tesla issued a touchscreen failure recall for just under 135,000 cars, after the National Highway Traffic Safety Administration found that the 8GB eMMC NAND flash memory device is reaching its 'lifetime wear' limit. Certain display functions fail as a result. It is alleged that Tesla's Al Prescott (Vice President of Legal) has confirmed an expected average chip lifespan of between five and six years. The recall has been extended since to Great Britain. Given that an average UK car is aged over eight years-old, we hope that carmakers will ensure that their touchscreens have a more realistic expected lifespan, especially if they insist on integrating vital functions into them.
AUDI A5: B-CYCLE COMBUSTION
NEW CAR TECH
Despite their respective marketing departments' efforts to keep the brands apart, Most Audis share their mechanical entrails with the less glamorous Volkswagen, Seat and Skoda brands. A clear example of this is the 190PS 2.0-litre petrol TFSI engine being employed by various Audi models (including the pictured A5), which is used to power the Volkswagen Arteon as well, a model that AT investigated in last month's New Car technical review.
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The B-Cycle method of combustion, as named after one of the company's powertrain engineers, Ralf Budack, is a particular highlight. The Budack Cycle closes the inlet valve before the piston reaches BDC. Not only does the piston encounter less resistance after it starts to rise on the compression stroke, in-cylinder temperatures also reduce. While these conditions make the engine more efficient under part-load conditions, it is also less powerful. Therefore, when the driver demands full power, the inlet valve's timing reverts back to that of the more conventional Otto Cycle, by switching to a different camshaft lobe. Note also that this engine employs both direct and port injection. One of the advantages of positioning a secondary injector behind the inlet valves is that it reduces the chance of intake tract coking, an issue that afflicts many GDI vehicles and is becoming a growing issue for aftermarket garages to resolve.
