Volkswagen explains WLTP changes due in September
Mandatory for all newly registered vehicles with the second stage of the WLTP type test, Volkswagen has set about trying to explain the complicated emission standard of Euro 6d TEMP EVAP ISC.
Last year’s WLTP test-procedure – introduced on 1 September 2018 – will see new technical requirements and increased procedures in type testing from 1 September 2019.
The ‘EVAP’ abbreviation refers to doubly difficult fuel-tank system evaporation measuring, which will be tested for 48 hours at constant limit values 35ºC and a maximum of 2 grams petrol vapour detected, whereas previously tests endured for 24 hours. Cars are already fitted with an activated charcoal filter to prevent petrol vapour being released to atmosphere, while new technology solutions will be used to meet the updated requirements.
Another major change with the second WLTP stage is the measurement of whether the emission limits are still met during vehicle operation. In future, vehicles up to five years old will be subjected to a random WLTP test.
Field monitoring (ISC = InServiceConformity) is designed to continue testing a vehicle already on the road, to see whether emissions limits are still met. In the future, vehicles aged five years and with a mileage up to 100,000km will be selected at random. Volkswagen uses a mobile exhaust gas measurement laboratory for on-site measurements of customer vehicles.