Volkswagen Polo Facelift 14

Volkswagen may be paying a heavy price for its diesel emissions scandal, but it turns out other car companies aren’t squeaky clean when it comes to applications involving oil burners, and it has nothing to do with cheating, manipulation or subterfuge, but rather because of inherent flaws in the system.

Essentially, it’s about not being able to live up to standards, in this case unrealistic ones brought about by the European New European Driving Cycle (NEDC) test cycle, supposedly meant to be representative of a car’s typical use on the Continent.

Long criticised for achieving fuel consumption figures that are unattainable in regular use (much like the earlier Japanese 10-15 mode), the cycle is also showing up emissions, with real-world figures nowhere close to that being listed in regulatory tests.

The Guardian reports that a more detailed analysis of diesel cars from a number of manufacturers have shown that they emit significantly more NOx levels on the road than in tests. The series of realistic on-road tests exposes the flaws quite noticeably – the publication said that tests revealed that some models emitted six times the regulatory limit of NOx pollution, and some unnamed 4×4 models were putting out 20 times that.

VW jetta TDI US-spec

The publication had earlier revealed that diesel cars from a host of manufacturers – Renault, Nissan, Hyundai, Citroen, Fiat, Volvo and Jeep – put out significantly more NOx than listed, in more realistic driving conditions.

Stringent tests carried out on diesel offerings from Mercedes-Benz, Honda, Mazda and Mitsubishi vehicles have shown these to be doing the same, with no evidence of illegal activity – such as the “defeat devices” used by Volkswagen – present.

The new data was obtained from Emissions Analytics’ on-the-road testing programme, which is said to closely match the real-world test the European commission wants to introduce – the planned World Light Test Procedure (WLTP), developed under the workings of the UNECE WP29 forum, targets a more realistic representation of fuel economy and pollutant/CO2 emissions.

Under such testing, the Emissions Analytics data – which were seen by the publication – stated that Mercedes-Benz’s diesel cars produced at least 2.2 times more NOx than the official Euro 5 level and five times higher than the Euro 6 rating, while Honda’s diesel cars emitted between 2.6 and six times that stated officially.


Meanwhile, the NOx readings from Mazda’s oil burners were between 1.6 and 3.6 times higher than reported NEDC test levels, while Mitsubishi’s diesels placed out levels between 1.5 and 3.4 higher. Emissions Analytics data also showed Citroen, VW and Audi NOx emissions to be higher on the road than in the EU lab test, The Guardian reported.

The report adds that both Mercedes and Honda said that they welcomed the planned regulatory reforms. “Mercedes-Benz emphatically supports the introduction of the WLTP test [which] is designed to supersede the NEDC, with the goal of bringing standardised and real-world consumption closer together,” a company spokesman told the publication. Honda, meanwhile, said it was open to additional testing in order to help strengthen regulatory and consumer confidence.

There may be a while before full resolution to the matter happens, and actual numbers reflecting real-world usage and conditions comes about. It was reported by Reuters that ACEA chairman and Renault CEO Carlos Ghosn said, in a letter to EU officials, that no significant progress on NOx was possible before 2019.

The news agency reported that the ACEA told the officials earlier in the month that the NOx limit for a new, more realistic test should be 70% higher than the current limit. And so, we can expect that the dirty talk will continue for a good while.