Fuel component identification

摘要

A method adjusts fuel injection based on a fuel make-up, such as a fuel ethanol content. The fuel make-up may be learned during transient conditions by correlating transient fueling effects caused by the different evaporation rates of higher and lower ethanol content to measured exhaust air-fuel ratio. In this way, an ethanol content independent of combustion stoichiometry can be obtained, even during transients, that is less sensitive to part variation and sensor drift.

主权项

1. A method, comprising:
adjusting engine operation in response to a fuel make-up, the fuel make-up based on a comparison of a first difference to a second difference, the first difference being between a first estimated air-fuel ratio at a higher assumed ethanol percentage and a second air-fuel ratio at a lower assumed ethanol percentage, the second difference being between a measured air-fuel ratio and an average of the first and second estimated air-fuel ratios, the estimated air-fuel ratios being based on variation in evaporation of fuel on an engine intake port.