The rise in customer complaints about vehicles not delivering the mileage as claimed by automotive manufacturers and fuel efficiency remaining below the claimed levels has prompted the Automotive Research Association of India (ARAI) to work on bridging this mileage gap with testing systems.
The difference has widened with the E20-blended fuel further reducing the mileage by 2-6%. ARAI and OEMs have acknowledged that E20-blended fuel reduces fuel economy.
ARAI conducts and certifies fuel efficiency, and OEMs quote ARAI fuel efficiency numbers while marketing the vehicles. ARAI is enhancing its testing protocols to align with the more rigorous WLTP (Worldwide Harmonised Light Vehicles Test Procedure), which is an improvement over the current tests.
ARAI director Reji Mathai said they are adopting the WLTP, which will reduce the performance gap between laboratory tests and real-world conditions.
According to Mathai, there have always been variations between mileage under test conditions and mileage under real-world conditions, and it has never been an issue. Some factors affect fuel efficiency, including road conditions, driving behaviour, fuel, and vehicle condition.
But people have now become more sensitive to these variations and want their vehicles to deliver the promised fuel efficiency, Mathai said.
At present, tests are conducted in controlled lab environments using a chassis dynamometer. Vehicles are subjected to standardised cycles, such as the Modified Indian Driving Cycle (MIDC) or evaluated at specialised test tracks such as the NATRAX.
The MIDC test runs for about 19 minutes over a simulated distance of 10 km, averaging speeds around 31 km/h to establish base efficiency and tailpipe emissions. The new test bench will put the vehicle through tough conditions for 400 hours.
With the new tests, Mathai said, they will get mileage as close as possible to real-world conditions, as the vehicle will be put through aggressive testing standards with high speeds, acceleration and dynamic braking that mimic driving conditions.
ARAI has upgraded its testing infrastructure to be compliant with AIS 175 – WLTP. It has upgraded the 4×4 chassis dynamometer and test automation systems.
These advancements align with the upcoming AIS 175 WLTP regulation, which will be implemented in the country. AIS 175 will be effective April 1, 2027, and mandates that all new passenger and light commercial vehicles up to 3.5 tonnes be tested on a chassis dynamometer using this global driving cycle.