Multi-fuel internal combustion engine

Abstract

This invention provides a multi-fuel internal combustion engine. The multi-fuel internal combustion engine is operated by leading a single low-boiling point component fuel and at least one fuel different from the single low-boiling point component fuel in properties either each solely or together to a combustion chamber (CC). The multi-fuel internal combustion engine comprises lubricating oil temperature detecting means (temperature sensor (91)) for detecting the temperature of a lubricating oil or lubricating oil temperature estimating means for estimating the temperature of the lubricating oil, and purge control means (electronic control unit (1)) which, when the temperature of the detected or estimated lubricating oil is around the boiling temperature of the single low-boiling point component fuel, prohibits purge control by an evaporation gas purge apparatus (comprising an evaporation gas passage (42), a check valve (43), a canister (44), and an opening / closing valve (45)), or reduces the purge flow rate of the evaporation gas in the purge control.

Description

technical field [0001] The present invention relates to a multi-fuel internal combustion engine that operates using a single low-boiling component fuel typified by alcohol fuel and at least one fuel whose property state is different from the single low-boiling component fuel. Background technique [0002] Generally, fuel evaporation gas is generated by evaporation of fuel stored in the fuel tank. The fuel tank is generally sealed, and its internal pressure rises with the increase of the boil-off gas, so if the pressure is not released to the outside, damage or the like may occur. However, since this boil-off gas contains harmful hydrocarbon (HC) components, for example, if it is a product of gasoline fuel evaporated, it cannot be directly discharged into the atmosphere from the viewpoint of environmental performance. Therefore, in the past, in the internal combustion engine, the evaporated gas is prepared to be adsorbed by the activated carbon in the canister, and introduce...

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Problems solved by technology

For this reason, even if the purification control is performed according to the concentration of alcohol in the fuel tank as in the above-mentioned Patent Documents 3 and 4, the actual air-fuel ratio in the combustion chamber may become too high due to the inflow of a single low-boiling point component. It is rich in the target air-fuel ratio, so in this case, it may lead to deterioration of emission performance and drivability

[0010] Here, although the following point of view can also be established, that is, the injection amount of the fuel injection valve can be suppressed by considering the inflow amount of a single low boiling point component into the combustion chamber. However, there is a limit to the reduction of the injection amount. Even if the injection amount is reduced to the minimum injection amount of the fuel injection valve, if a single low-boiling point component that is larger than the reduced amount flows into the combustion chamber, the actual amount in the combustion chamber It is conceivable that the air-fuel ratio becomes too rich than the target air-fuel ratio (rich), and the deterioration of emission performance cannot be suppressed.

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