Educating Engineers on the Use of Renewable Ethanol Fuel as a Drop-in Replacement for Gasoline in Small Engines
G. W. Davis and A. J. Mazzei Department of Mechanical Engineering, Kettering University, Flint, MI (USA) 2026-01-20

Abstract

The use of high-blend ethanol fuels to reduce emissions produced by on-road vehicles has been extensively studied. However, much less research has been done to study the effect of operating small off-road engines on high-blend ethanol fuel as a drop-in replacement for gasoline. Most small engine manufacturers only certify proper operation on low ethanol blends such as E10 (10% ethanol, 90% gasoline by volume).

Most engineering students are unaware of the benefits that can be achieved when using high-blend ethanol fuel in small engines without substantial modifications. In this study, students conducted performance testing and analysis of a small engine using a dynamometer and a raw exhaust emissions analyser. The exhaust emissions and performance of the engine were evaluated using the U. S. Environmental Protection Agency (EPA) 6-mode duty cycle for small recreational engines (under 19 kW). Testing and analysis followed the recommendations of the SAE J1088 recommended practice.

Students were motivated by the contemporary nature of the project and the use of commercially available equipment
for testing. Further, students learned about the use of standardized testing to demonstrate the performance and
emissions results.

Key words: Ethanol, engine, emissions, education, fuel.

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