India's push for higher ethanol-blended petrol, specifically E20 fuel containing 20% ethanol, may pose risks for vehicles originally designed to run on E10 petrol. A study conducted by the Automotive Research Association of India (ARAI) highlights potential issues for older cars and two-wheelers, though the findings vary across vehicle types.
Rubber Components at Risk in E10 Vehicles
The primary concern flagged by the ARAI study is the gradual deterioration of rubber components within the fuel system of E10-compatible vehicles when exposed to E20 petrol. These critical parts include hoses, gaskets, seals, and O-rings. The report suggests these components may require replacement after prolonged use with the higher ethanol blend.
While rubber parts showed vulnerability, the study found no adverse effects on metallic components across the tested vehicles. Additionally, emissions from E10-compatible vehicles operating on E20 fuel remained within legally prescribed limits, easing environmental concerns.
Mixed Durability for Four-Wheelers
Engine durability assessments for four-wheelers presented a mixed picture. One Original Equipment Manufacturer (OEM) reported no issues after 400 hours of testing, with engine performance remaining acceptable. However, another manufacturer observed a "thermomechanical failure of exhaust valve" in an engine tested for a cumulative 809 hours. Experts involved in the study noted that other factors unrelated to E20 fuel could have contributed to this specific valve failure, and typical engine durability tests often extend to approximately 2,000 hours.
Further, a Bharat Stage-IV (BS-IV) engine maintained acceptable performance with E20 fuel, but an issue was identified with a BS-VI turbo-charged engine after 265 hours of durability testing.
Two-Wheelers Show Resilience
In contrast to some four-wheeler findings, two-wheelers demonstrated considerably better resilience. Engine durability tests across three different manufacturers revealed no issues, with the study concluding that their performance is acceptable when using E20 fuel.
Impact on Fuel Efficiency
Across all vehicle types studied, the ARAI report indicated a slight reduction in fuel efficiency when using E20 petrol compared to E10. Fuel consumption was found to be approximately 2% to 6% higher, with the exact increase varying by model. This means that while E20 is promoted as a greener and potentially more cost-effective option in the long term, everyday users might experience marginally more frequent refuelling.
The findings from this ARAI study provide crucial insights into India's ethanol blending program, emphasizing that while the transition to E20 is largely viable, older vehicles and certain engine configurations may need closer monitoring and potential component replacements over time.