New research from the Automotive Research Association of India (ARAI) indicates that vehicles using E20 petrol, a blend of 20% ethanol and 80% gasoline, may experience a 2-6% decrease in fuel efficiency. However, the government-backed agency has definitively ruled out any risk of engine breakdowns or significant performance issues in vehicles designed to be compatible with the higher ethanol blend.
Understanding the Mileage Impact
ARAI's comprehensive testing, conducted in collaboration with original equipment manufacturers (OEMs), revealed that the slight reduction in fuel economy is primarily due to ethanol's lower energy content compared to traditional petrol. Dr. Reji Mathai, Director of ARAI, explained that this lower calorific value naturally leads to a modest dip in mileage.
Despite the mileage change, key vehicle performance aspects such as drivability, engine startability, and acceleration remain unaffected. The studies also highlighted a positive environmental impact, recording significant reductions in carbon monoxide (CO) and unburnt hydrocarbon (HC) emissions.
Long-Term Durability and Compatibility
The durability studies involved rigorous long-term trials, covering 40,000 kilometers for passenger vehicles and 20,000 kilometers for two-wheelers. These extensive tests confirmed that E20 fuel is safe for regular use in compatible vehicles. Fuel system components made of metal and plastic showed good compatibility with the E20 blend.
However, ARAI noted that some older vehicles not originally designed for E20 might experience faster degradation of certain rubber hoses, seals, and gaskets, potentially requiring earlier replacement. The tests encompassed vehicles ranging from three to nearly ten years old, with the observed mileage drop varying based on the specific vehicle model.
Future Outlook: E25 Petrol Under Evaluation
Looking ahead, ARAI is already evaluating E25 petrol, a blend containing 25% ethanol. This new study aims to assess its impact on fuel efficiency, engine health, long-term durability, emissions, and overall operating costs. The E25 research is expected to involve real-world testing over distances of 60,000-70,000 kilometers and will also determine if vehicles certified for E10 or E20 can safely operate on E25 without increased maintenance or performance degradation.