Controller for diesel engine and method of controlling diesel engine

Abstract

An electronic controller for a diesel engine (1) performs primary injection control in which primary injection of fuel is controlled based on an operational status of the diesel engine and additional injection control in which additional injection of the fuel is controlled for estimation of a cetane number of the fuel. The electronic controller includes a control means that, as the additional injection control, causes a plurality of fuel injections to be performed at different injection timings as the additional injection, calculates the amount of increase in torque of a crankshaft (14) due to each of the fuel injections, estimates injection timing at which misfiring starts to occur based on a trend of variation in the calculated torque increase amount as the injection timing of the fuel injections is shifted in one direction, and estimates the cetane number of the fuel based on the estimated injection timing.

Description

technical field [0001] The present invention relates to a control device of a diesel engine performing fuel injection control and a method of controlling the diesel engine. Background technique [0002] In a diesel engine, fuel injected by an injector into a combustion chamber is compressed and ignited after a certain period of time has elapsed from injection, that is, after an ignition delay has elapsed from injection. In order to improve the engine power and emissions of diesel engines, a control device that controls fuel injection timing, fuel injection amount, etc. based on the operating state of the engine in consideration of this ignition delay is widely used (see, for example, Publication No. 2001 -152948 Japanese patent application). [0003] For fuels used in diesel engines, the lower the cetane number, the longer the ignition delay. Thus, for example, even if the optimal fuel injection timing and the optimal fuel injection amount are set based on a given standard...

AI Technical Summary

Problems solved by technology

Thus, for example, even if the optimal fuel injection timing and the optimal fuel injection amount are set based on a given standard cetane number when the diesel engine is shipped out, if a fuel with lower cetane such as winter fuel value of fuel is supplied to the fuel tank, the fuel ignition timing is retarded and the combustion state deteriorates, which may lead to misfire in the worst case

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