The Autocar guide to WLTP emissions testing

The Autocar guide to WLTP emissions testing

Simon Lambert, technical boss at Caterham, said that the biggest challenge the firm had to overcome to hit the September 2018 deadline was the lack of its own test facility. 

He adds: “We also found that the emission test operators struggled with the immediacy of the throttle response and engine braking on a Seven. That meant it was easy to drop out of the acceptable window of tolerance during the drive cycle. With NEDC, that window was visible to the tester during the test, making it much easier to follow [so a breach was rare]. 

“With WLTP, it isn’t. This meant that we only found out if this had happened post-test, invalidating the test and leaving us waiting days/weeks for a retest. Not because the car was failing, but because it was difficult for the human element of the test.” 

Lambert believes it’s important that Caterham cars are clean and comply to the latest standard, but points out that specialist cars cover “tiny mileages compared to regular road cars, so the actual annual emissions output is a fraction of what a typical BMW or Ford might produce during a year’s use”. 

He adds: “Blanket legislation like this does not take into consideration the scale of the challenge for an ultra-low-volume manufacturer like Caterham. To be asked to achieve this within the same timescale as a major manufacturer with all its resources is unreasonable.” 

Why WLTP isn’t really worldwide

The aim of the Worldwide Harmonised Light Vehicle Test Procedure, as the name suggests, is to create a global standard for emissions testing. Trouble is, it’s neither worldwide nor harmonised.