In a new development, a report by the Automotive Research Association of India (ARAI), which had recommended the rollout of E20 fuel, found that rubber components in fuel systems of E10-compliant vehicles show wear when run on E20. The unpublished report, reported by TOI, used as a reference by the government and vehicle manufacturers, said hoses, gaskets, seals and O-rings in these vehicles 'may need replacement.'
Rubber parts show deterioration
According to the ARAI report accessed by TOI, E20 fuel caused visible deterioration in rubber components fitted in E10-compliant vehicles. The study did not specify a timeline for replacement but flagged the parts as vulnerable to the higher ethanol blend.
Engine durability tests give mixed results
The report's engine durability tests threw up contrasting results across manufacturers. A BS-IV engine performed acceptably on E20, the report noted, but a BS-VI turbocharged engine ran into trouble after 265 hours of testing.
Two four-wheeler OEMs conducted separate durability tests. One reported no issues after 400 hours, with performance termed acceptable on E20. The other recorded valve failure caused by combined heat and mechanical stress after the engines were run for a cumulative 809 hours.
A thermomechanical failure happens when extreme heat combined with repeated physical strain causes an exhaust valve to warp, crack or fracture. People familiar with the findings said other factors could have contributed to the failure in the second case. Experts who work on vehicle testing pointed out that durability tests are typically conducted over 2,000 hours, longer than the duration at which the failure was recorded.
Two-wheelers clear tests, fuel consumption rises
Three two-wheeler manufacturers ran engine durability tests and reported no problems, with performance rated acceptable on E20, the report said.
Across all vehicles tested, the ARAI report found E20 caused no damage to metallic components, and tailpipe emissions stayed within legislative limits set for E10-compatible vehicles. Fuel consumption, however, rose between 2% and 6% compared to E10, though the increase varied by vehicle. Evaporative emissions remained within legislative limits, and startability and drivability were rated satisfactory on E20.
