DPF'S: When specialists come together Diesel Particulate Filters (DPFs) like keeping clean but short journeys, low speeds and upstream faults prevent them from being so. Therefore, Rob Marshall looks at the DPF specialist market, as well as the importance of partnering with dedicated suppliers. If you believe in the wider media hype, diesel is dead. Despite car registrations declining, diesel sales remain an important part of the mix. Some environmentalists are now calling for diesels to be promoted more heavily to balance the extra CO2 generated by the production of electric cars and the increasing popularity of petrols. It is a delicious irony. As we should believe that diesels are the new bogeyman, one would have thought that the DPF cleaning and repair market would be in freefall. This is not the case. Interestingly, Kalimex's Mike Schulp predicts growth for 2021. He reasons that the latest diesels possess DPFs and the majority of them have the extra complication of SCR catalysts, with which the aftermarket is becoming familiar. Furthermore, private owners are hanging on to their diesel cars for longer. A look at the used
Low mileages and reduced driving speeds promote DPF soot blockages but so do other faults. Should you encounter a DPF blockage complaint, keep an open mind.
car market reveals that demand for used diesels are high and their residuals are stronger than PHEVs and even EVs. The need to keep older diesel cars running at their peak, therefore, has never been higher.
The COVID complex As investigated in AT's last issue, the more frequent short trips and reduced mileages that characterised many private motorists' usage patterns over 2020/21's particularly harsh winter is harder on the car overall than longer journeys and prolonged higher speeds. The main issue involves increased contamination build that can afflict a number of systems beyond the DPF, including fuel injectors, EGRs and PCVs. DPF soot loadings are affected not only by a decreased efficiency of these systems (and more) but also by the low speed, low load and low temperature nature of driving conditions enforced by wintertime COVID legislation. While BG Products cites that fewer cars entered garages over lockdown, demand for DPF services seems to be increasing. Gary Wood is not only the technical adviser for Randstad and TerraClean service centres but he is also a garage owner and reports that he has been just as busy (if not busier) with DPF issues. Gilbert Groot of the Dutch specialist, JLM Lubricants, admits that DPF cleaning demand has increased substantially during 2020 and 2021, not only in the UK but also in those nations where diesel vehicles are relatively popular.
DPF'S
DPFs are not always this accessible. Note the AdBlue injector and SCR catalyst, positioned to the left of this system.
Consider also that the authorities want to keep vehicles of 'Diesel-gate' age working as close to their peak as possible. According to the DVSA, almost 1.3 million vehicles failed MOT tests last year due to excessive tailpipe emissions. Notably,
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