Fuel efficiency can drop by 2-5% due to E20 petrol, say experts

Ethanol-blended petrol has been making quite some headlines in India. The E20 petrol, which contains 20 per cent ethanol blended with petrol, has left many automobile owners in a dilemma, worrying about their vehicle health, fuel economy, etc. When it comes to fuel efficiency, automotive industry experts say the E20 could lead to a drop between two and five per cent, depending on the type of cars.

PTI has reported that it spoke to some of the automotive engineers working with some of the major automakers amid the social media debate over the impact of E20 fuel on vehicles. They reportedly said that in the older vehicles, which are not E20 compliant, there could be erosion of gaskets, fuel rubber hoses and pipes in the long term. However, these issues will not occur immediately. "There can be a drop in mileage ranging from two-five per cent, depending on the type of vehicle. This is purely because of the lower calorific value of ethanol compared to petrol," said an expert requesting anonymity.

Earlier this month, the Ministry of Petroleum and Natural Gas (MoPNG) clarified that the critiques suggesting that E20 causes a drastic reduction in fuel efficiency are misplaced. However, the ministry did not state the percentage drop in fuel efficiency. "The efficiency drop (if any) in E10 vehicles has been marginal. For some manufacturers, vehicles have been E20 compatible from as far back as 2009. The question of any drop in fuel efficiency in such vehicles does not arise," the ministry had said.

The ministry also stated that vehicles tuned for E20 deliver better acceleration, which is a very important factor in city driving conditions. Additionally, ethanol's higher heat of vaporisation reduces intake manifold temperatures, increasing air-fuel mixture density and boosting volumetric efficiency. On August 4, the MoPNG, in a post on X, said that ethanol, being lower in energy density than petrol, results in a marginal decrease in mileage, estimated at one- two per cent for four-wheelers designed for E10 and calibrated for E20, and around three-six per cent in others.

Speaking about the E20 fuel's impact on engines, an automotive expert reportedly said that the use of the fuel will not have any impact on engines of compliant vehicles, as the materials are tuned for it. However, in vehicles, which are not E20 compatible, there could be erosion of gaskets and fuel rubber hoses and pipes in the long term, but not immediately.

Get insights into Upcoming Cars In India, Electric Vehicles, Upcoming Bikes in India and cutting-edge technology transforming the automotive landscape.