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With the UK Government enforcing European Whole Vehicle Type Approval emissions compliance on the aftermarket, Rob Marshall consults with leading filtration experts to determine what the future holds.
While the motorcar has transformed Western society, it cannot be denied that its tailpipe emissions are a notable challenge. This was not much of a problem, when motoring was a pastime for the select few but, as multiple-car households have become the norm and our roads have become increasingly congested, legislators stepped in, piling pressure on car manufacturers to make their cars cleaner.
Influenced heavily by California mandating new car emissions standards from the mid-1960s, in a reaction to trapped smog building within the Los Angeles basin, European nations drew up their own mandatory standards for new cars through the European Economic Commission of the United Nations (UNECE), of which the UK was a signatory before it became a member of the Common Market.
What is Whole Vehicle Type Approval?
While it is not our intent to provide complex legal analysis, technicians need to understand Whole Vehicle Type Approval and how it relates to aftermarket maintenance, repairs and even modifications.
Whole Vehicle Type Approval harmonises technical criteria for new cars. One such example, which is becoming increasingly relevant, is what defines a motorcar as opposed to, for instance, a quadricycle. This explains why a Citroën Ami, with its 28mph top speed, does not have to comply with the same rules as a Berlingo.
Naturally, these rules include environmental standards, especially since the first EURO emissions specifications were mandated in 1992, with subsequent levels rising to EURO 2 (1996), 3 (2000), 4 (2005) and 5 (2009). It is worth noting that these laboratory-assessed tests were performed on a single test vehicle and some of the exhaust gases measured are not considered at the MOT Test. This is an important consideration, because a car might pass an MOT emissions test, yet not comply with the emissions standards set when it was new – i.e. Type Approval compliance. Technically, if used on the road, the driver is likely to commit an offence, despite achieving a Test pass.
As these standards became stricter, it became obvious that political ambition was overtaking technical reality. This led many manufacturers to program their cars to produce artificially low emissions, when they detected a Type Approval emissions test. The result was the Diesel Gate scandal of 2015. The legislators reacted swiftly. After Euro 6 (2014) was introduced, the UNECE revised its test protocols to ensure more representative results. This led to Euro 6c in 2017, where cars were tested under the Worldwide Harmonised Light Vehicle Test Procedure (WLTP), while Euro 6d-TEMP and Euro 6d (2020) cars were tested under the RDE (Real Driving Emissions) standards. Euro 6e (2023) focusses on PHEVs.
How does Whole Vehicle Type Approval affect the aftermarket?
As a pan-European requirement, member states differ in how they enforce Construction and Use rules. Germany is noted as one of the most rigid countries, whereas the UK is more relaxed. This situation is evolving, however, and our MOT Test is including elements of Type Approval compliance checks. The most obvious of these are visual inspections for missing or tampered emissions-control equipment, such as welded-up DPFs. Note also that, while most replacement aftermarket parts do not require Type Approval testing, it is mandatory for certain safety and emissions equipment. These include catalytic converters and particulate filters for the majority of modern vehicles.
British law states that the driver commits an offence if the vehicle does not comply with the emissions standards to which it was designed to meet, under 61a (3) of the Road Vehicles (Construction and Use) Regulations. Moreover, Section 42 of the Road Traffic Act is more relevant to the independent garage owner, because it places liability on the person who causes, or permits, the use of a vehicle that does not comply with a Construction and Use requirement.
Even so, the UK Government says the regulations do not cover Euro 5 and beyond. During the summer, it launched a consultation (which ends on 6th September) to extend British law into the more recent EURO standards and to impose unlimited fines for non-compliance by next summer. For more information, see HERE.
While the Department for Transport states an intent not to prohibit all vehicle modifications, its stance on the legality of a modification, whether hardware, or software, depends primarily on how that modification affects the standard to which the car was built. For now, it states that it considers “pop and bang” exhaust modifications, manipulations to EGRs and SCR systems, and the deletion of catalysts, DPFs, and GPFs to be modifications it always considers illegal. We are also aware that the DVSA enforcement unit is prosecuting aftermarket firms successfully for implementing these modifications, which has led to case law being established: click HERE
What about maintenance considerations?
An interesting development in these proposals is that the UK Government does not distinguish between a badly judged modification and poor maintenance, because both raise emissions. Naturally, poor maintenance could be defined as owner neglect, a workshop not performing the work correctly, or low-grade parts being fitted, such as filters.
Currently, carmakers’ emissions technology must work as intended for 60,000 miles, or five years (whichever comes first). As covered in our previous braking feature, the forthcoming EURO 7 is doubling these expectations, and we expect these newer vehicles to become even more sensitive than current models at illuminating their EMLs the moment emissions stray beyond their very tight parameters.
As the DVSA appears intent on stepping up real-world emissions enforcement from next summer, aftermarket garages should consider the potential additional responsibilities they have to ensure that the vehicles they look after remain compliant not only with MOT emissions standards but also with those of Type Approval. Naturally, the first part of this is not disabling any emissions control equipment, or performing modifications that are likely to increase pollution levels. Yet, there are other considerations, too.
Most technicians realise that a car with neglected or poor-quality filtration is more likely to produce higher emissions. While the DfT states in its consultation stage that it is not seeking to mandate manufacturer-specific original equipment manufacturer (OEM) parts only, it advises (somewhat vaguely) that, “Anyone installing parts to vehicles does check that they are legally approved for use.”
Naturally, this is not always practical. Mahle Aftermarket tells us that the responsibility to avoid degrading the vehicle's emission performance over its lifetime becomes more consequential under Euro 7.
What do filtration firms say?
UFI acknowledges that, because Euro 7 demands that tailpipe emission compliance must be sustained over a greater mileage, maintenance quality will become critical. This, UFI reckons, will create a clear advantage for suppliers, who are capable of transferring genuine OE engineering, material specifications and validation standards directly into their aftermarket portfolios. Mahle Aftermarket agrees but adds that while filtration is a contributing factor, emissions compliance relies on proper filtration working with correct calibration and hardware, including catalysts, particulate filters and SCRs being in sound order. Meyle adds that correct installation is also vital.
Even so, should you fit a sub-standard filter, UFI says that the premature clogging will result in a pressure drop, forcing the engine to work harder, which increases fuel consumption and, therefore, emissions. Low-grade materials will also break down faster under chemical and thermal stress, allowing contaminants to bypass the filter and causing more wear and elevated emissions. It also notes that poor design can add weight, which, in turn, negates efficiency.
UFI emphasises, therefore, that to maintain baseline emissions, a filter must sustain precise retention efficiency, have a low-pressure drop and maintain structural integrity throughout its lifespan.
While Mahle Aftermarket highlights that it is not the case that any lower-quality filter will automatically, or predictably, raise tailpipe emissions, much depends on the engine design, operating environment, or maintenance interval. Yet, it acknowledges that aftermarket workshops and fleet operators may need to pay closer attention to whether replacement filters meet the technical requirements of the latest vehicles, especially those within the forthcoming EURO 7-era. This does not mean that filters must replicate OE specifications in every respect but they should not compromise durability, or emissions performance. Mahle Aftermarket, therefore, reasons that trusted brands can offer the transparency that the market will need as vehicle emissions monitoring becomes more widespread.
Meyle shares this stance in supporting workshops with reliable replacement parts for increasingly complex vehicles. Its strategies include monitoring new regulatory requirements (including Euro VII) and continuing its product development and testing to meet evolving vehicle technologies.
What about costs?
Especially as filtration will be an important part of maintaining Type Approval emissions compliance on the road, we wondered whether this would lead to price increases.
Quite reasonably, Mahle Aftermarket explains that higher durability and performance requirements tend to translate into higher manufacturing, validation, and materials costs, especially as Euro VII requirements can affect filter media specifications, housing design and testing. Yet, it adds that it is difficult to quote per-filter cost impacts, because industry estimates for Euro VII adaptation vary. The final figure, ultimately, depends on the vehicle and its engine. Even so, it concludes that the cost of a quality filter is modest, compared with the cost of a replacement aftertreatment part, or engine repairs.
UFI concludes that while stricter standards require advanced materials and engineering, continuous innovation in media design and manufacturing should prevent notable price increases. It agrees with Mahle Aftermarket that, from a total cost-of- ownership perspective, a high-specification filter protects the engine and the other vehicle systems from falling foul of the regulations. Therefore, the value of long-term protection outweighs any minor cost uplift.
