Reducing intake manifold pressure during cranking

Abstract

Embodiments for starting an engine are provided. In one embodiment, an engine control method comprises, during engine cranking, commencing fuel injection when intake manifold pressure drops below a threshold, the threshold based on fuel volatility. In this way, the stability of engine starts using low volatility fuels may be increased.

Description

technical field [0001] The present disclosure relates to starting an internal combustion engine. Background technique [0002] Alternative fuels have been developed to mitigate the rising price of traditional fuels, to reduce dependence on imported fuels, and to reduce the generation of emissions such as CO2. For example, alcohols and alcohol-based fuel blends have been recognized as attractive alternative fuels, especially for automotive applications. However, alcohols and alcohol-based fuels are less volatile than gasoline, and thus may not evaporate efficiently at typical engine starting temperatures and pressures. Therefore, engine starting using alcohol and alcohol-based fuels, especially cold engine starting, can be difficult. Further, incomplete evaporation of fuel may reduce fuel economy and reduce emissions. Contents of the invention [0003] The present inventors have recognized the above problems and provided a solution to at least partly address these proble...

AI Technical Summary

Problems solved by technology

However, alcohols and alcohol-based fuels are less volatile than gasoline and therefore may not evaporate efficiently at typical engine starting temperatures and pressures

Therefore, engine starts using alcohol and alcohol-based fuels, especially cold engine starts, can be difficult

Further, incomplete evaporation of fuel can reduce fuel economy and reduce emissions

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