Combustion detecting method of engine

Abstract

A combustion phase detection method is able to reduce exhaust gas and to improve combustion stability, to compensate injection and ignition delay time between combustion chambers and between cycles, and to detect a combustion phase in real time such that a heat generation rate and a heat release can be effectively calculated at an early state of the combustion by using a combustion pressure and a motoring pressure difference of an engine not affected by an offset value of the cylinder pressure. The combustion phase detection method of an engine may include detecting a combustion phase according to fuel injection timing by using a specific point of DHdP that is calculated by the following heat release equation: DHdP:[integral]1 / [gamma]-1VdPdiff / d[theta]d[theta]. Here, Pdiff is a difference (Pdiff=P-Pmotoring) between a cylinder measure combustion pressure (P) and a motoring pressure (Pmotoring).

Description

[0001] Cross References to Related Applications [0002] This application claims priority and benefit from Korean Patent Application No. 10-2010-0094888 filed Sep. 30, 2010, the entire contents of which are hereby incorporated by reference for all purposes. technical field [0003] The present invention relates to a detection method of a combustion stage of an engine, which utilizes its combustion pressure and the rate of change of a motoring pressure difference. Background technique [0004] In internal combustion engines, abnormal combustion processes such as detonation can be produced by spontaneous combustion of unburned mixture that has not yet been touched by the flame. Prolonged continuous detonation can damage the components of the combustion chamber through increased thermal loads and pressure shocks. [0005] An important parameter influencing the knock tendency of an internal combustion engine is the ignition timing. Knocking occurs if the fuel / air mixture in th...

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Problems solved by technology

[0012] However, since the above heat generation analysis method is based on thermodynamic rules, and the method is mathematically extremely complex and has a large-scale calculation burden, it is effective in the case of analysis with sufficient time in terms of theory, but there is Disadvantages that it is difficult to apply it to engine combustion performed in real time

[0013] In addition, in the combustion stage detection method using the 50% point of heat generation (MFB50), such as figure 2 As shown, the problem is that, compared to the coordinates of the normal circle markers, such as image 3 As indicated by the coordinates marked in the box pattern in , when measuring the cylinder combustion pressure in the case of a deviation in the sensor measurement value due to thermal shock, the error in the detection of the combustion phase is larger

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