Average car owner can’t check mileage on their own: Nitin Gadkari amid E20 row
Amid the growing controversy over ethanol-blended petrol, Road Transport Minister Nitin Gadkari said the average car owner cannot accurately measure their vehicle’s fuel efficiency on their own and should rely on tests conducted by authorised dealers.
Gadkari, in an interview with ABP News on Monday, was responding to a journalist who claimed her car’s mileage in city driving had plummeted after switching to government-mandated E20 petrol.
When the journalist said the mileage of her car, purchased in 2023 and presumably E20 compliant, had fallen from 11 km/litre to 7 km/litre recently, Gadkari questioned how the figure had been calculated.
“I checked it in my car, just as everyone does,” she replied, referring to the dashboard mileage display.
To this, Gadkari, who has staunchly defended the ethanol-blending programme, reiterated that accurate fuel-efficiency readings can only be obtained through manufacturer-authorised testing equipment.
“You and I can’t check the mileage. A car’s mileage can only be checked using a company-authorised dealer’s machine,” he said.
The exchange comes days after the Centre acknowledged that E20 petrol can reduce fuel economy by 3-5% in some vehicles, even as it defended the fuel policy.
Last week, the Ministry of Petroleum and Natural Gas released a question-and-answer document aimed at addressing criticism of the Ethanol Blended Petrol Programme. In it, the government acknowledged that E20 petrol may lower fuel efficiency in some vehicles but argued that mileage is not the only factor to consider.
“It is true that in some vehicles there may be a 3-5% reduction in fuel economy. But mileage is only one parameter,” the ministry said.
The Centre mandated the nationwide sale of E20 petrol from April 1 as part of its push to increase ethanol blending, reduce dependence on imported crude oil and cut emissions.
The rollout has, however, received pushback from motorists and sparked concern among sections of the automobile industry. Car owners are reporting a drop in mileage, and some manufacturers have raised questions about the blended fuel’s performance in older vehicles.
CAN DRIVERS ACCURATELY CHECK MILEAGE AT HOME?
Not entirely. But they can get a fairly reliable estimate. Modern cars calculate fuel economy using data such as fuel injected into the engine, distance travelled and inputs from the engine control unit (ECU). While dashboard readings are estimates, they are often within 2-5% of manual calculations over a full tank, depending on the vehicle.
Automotive experts generally consider the full-tank method the most accurate real-world test. Drivers fill the tank, reset the trip meter, drive normally until the next refill, then divide the distance travelled by the litres of fuel added.
WHAT DOES A DEALER’S MACHINE MEASURE?
A manufacturer’s diagnostic tool does more than display fuel economy. It reads detailed data from the ECU and checks whether components such as fuel injectors, oxygen sensors and airflow sensors are functioning properly. It can also detect engine faults and verify ECU calibration that may affect fuel consumption.
However, it does not directly measure real-world mileage under every driving condition. Fuel economy is also influenced by traffic, city versus highway driving, air-conditioning use, tyre pressure, driving style and vehicle load.
HOW ACCURATE IS GADKARI’S CLAIM?
In practice, a vehicle’s onboard display provides a useful estimate, while the full-tank method offers a reasonably accurate measure of real-world fuel economy. Dealer diagnostic equipment is primarily used to identify mechanical or electronic issues affecting fuel efficiency rather than serving as the only valid way to assess mileage.
