Estimation method for combustion state of sub-cylinder of internal combustion engine

Abstract

The invention relates to an estimation method for a combustion state of a sub-cylinder of an internal combustion engine. The estimation method comprises the following steps: 1) arranging a cylinder pressure sensor in any sub-cylinder of the internal combustion engine; arranging a crankshaft rotating speed sensor on a crankshaft of the internal combustion engine; 2) solving an indicating torque sum of the sub-cylinders according to a rigidity model of an internal combustion engine crankshaft system; 3) resolving the indicating torque sum Ti <theta> so as to acquire the indicating torque of gas acting force of a current firing cylinder; 4) directly measuring the gas acting force indicating torque of the sub-cylinder provided with the cylinder pressure sensor during firing through the cylinder pressure sensor, evaluating difference of a measured value and the gas acting force indicating torque of the current firing cylinder acquired in step 3) so as to acquire error of the gas acting force indicating torque during the firing of the sub-cylinder provided with the cylinder pressure sensor, and using the error to correct an estimated value of the gas acting force indicating torque during the firing of the cylinder not provided with the cylinder pressure sensor. The estimation method provided by the invention can be widely applied to all kinds of electric control diesel engines and electric control gasoline engines.

Description

technical field [0001] The invention relates to an estimation method, in particular to an estimation method for cylinder-by-cylinder combustion state of an internal combustion engine. Background technique [0002] The use of internal combustion engine cylinder pressure signals for fault diagnosis and control has broad application prospects, but its practical application is limited by the cost of cylinder pressure sensors. For multi-cylinder engines, multiple cylinder pressure sensors are required, resulting in doubled costs. rise. The instantaneous speed signal of the internal combustion engine is another feasible solution to estimate the combustion state, but this method based only on the analysis of the crankshaft speed is difficult to be practical due to the limitations of accuracy, application range and algorithm complexity. Generally speaking, most estimation methods estimate the results The deviation is relatively large, but the relatively accurate estimation method i...

AI Technical Summary

Problems solved by technology

[0002] The use of internal combustion engine cylinder pressure signals for fault diagnosis and control has broad application prospects, but its practical application is limited by the cost of cylinder pressure sensors. For multi-cylinder engines, multiple cylinder pressure sensors are required, resulting in doubled costs. rise

The instantaneous speed signal of the internal combustion engine is another feasible solution to estimate the combustion state, but this method based only on the analysis of the crankshaft speed is difficult to be practical due to the limitations of accuracy, application range and algorithm complexity. Generally speaking, most estimation methods estimate the results The deviation is large, but the relatively accurate estimation method is difficult to implement due to the complexity of the algorithm and the large amount of calculation

In addition, the estimation method is also poorly reusable for different internal combustion engines

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