The European Commission has tightened the WLTP test for new cars after indications automakers were ‘gaming’ their results.
It may also demand manufacturers retest cars already signed off, leading to confusion in showrooms and where emissions figures are used by Governments to assess tax levels.
The updated regulation, which came into force in February, requires automakers to switch on all emissions-saving technology, such as the stop-start function, and use the same driver-selectable modes for each model tested, for example Eco mode instead of Sport mode.
The Commission discovered that automakers were turning on functions during tests that increased emissions in the runup to the introduction of WLTP testing on 1 Sept., said the green pressure group Transport and Environment.
The Commission found that some automakers were manipulating tests to burn more fuel and increase emissions with methods such as switching off the start-stop function in cars being tested, adjusting the gear-shift patterns, using the Sport instead of Eco mode, T&E said.
By artificially increasing their CO2 emissions now, automakers hoped to weaken future reduction targets, T&E said. The manipulation partly explains why there is a huge disparity in average emissions between different automakers, added T&E.
CO2 emissions increased when homologation tests in Europe switched to WLTP from the former NEDC homologation regime. The range of the increases was between 1 percent to 81 percent depending on the automaker but did not name the brands.