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Measured Emissions of Small Engines under Steady State and Transient Operation
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English
Abstract
The exhaust emissions of off-road and utility engines have recently come under increasingly thorough scrutiny and are now becoming the subject of federal regulations. While the most straightforward emissions guidelines relate to steady-state engine performance, it is well known that duty cycles of many small engines have a transient content and that its significance can vary strongly from application to application. Hence, it is important to examine how measured emissions change when the transient content of a test cycle is varied, and what kinds of steady-state and transient test cycles might realistically imitate operational conditions. These questions have been addressed in an experimental study in which several small two- and four-stroke engines have been tested under steady state and transient cycles. The same tests were also carried out when these engines had been adjusted to operate at leaner air-fuel ratios, as might be required by forthcoming regulations. The results of this study reveal some appreciable differences between steady-state and transient emissions of engines, particularly at leaner air-fuel ratios.
Authors
Citation
Brereton, G., Morrison, K., Chishty, H., Schwartz, G. et al., "Measured Emissions of Small Engines under Steady State and Transient Operation," SAE Technical Paper 941806, 1994, https://doi.org/10.4271/941806.Also In
References
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