The European Commission and the United Nations are reportedly in discussions about the way fuel economy tests are performed and calculated.
With current tests renowned for producing "combined" fuel consumption figures that are near impossible to achieve under normal driving circumstances, the new testing regime would aim to closer represent real-world driving.
Auto Express reports the new Worldwide Light-duty vehicle Test Cycle (WLTC) would be aimed at creating a testing standard for both fuel economy and exhaust emissions for markets around the globe including the UK, US, Europe, China, India, Japan and South Korea. The WLTC would also cover measurements for diesel particulates and energy consumption of electric vehicles and hybrids.
One idea being discussed suggests having two fuel consumption figures per vehicle: a best- and worst-case result. The best result would be a test with no passengers and all ancillary systems – air-conditioning, stereo and headlights – turned off, while the worst-case would see a full car load of passengers with all ancillaries left on.
In Australia our fuel consumption and CO2 emissions are calculated according to Australia Design Rule (ADR) 81/02 and consist of a 20-minute test cycle split into two parts, an ‘urban’ cycle which represents stop-start traffic and an ‘extra-urban’ cycle which involves the vehicle accelerating to a high peak speed. The ‘combined’ figure is determined by weighting the urban and extra urban figures based on distance travelled in each part of the test cycle.