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

A technology of combustion state and internal combustion engine, applied in the estimation field, can solve the problems of poor reusability of internal combustion engine, large amount of calculation, large deviation of estimation result, etc., and achieves simple combustion state feedback model, simple structure and installation arrangement, and high precision. Effect

CN104179573AActive Publication Date: 2014-12-03TSINGHUA UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2014-12-03

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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.
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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...

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Embodiment Construction

[0024] The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

[0025] The present invention proposes a method for estimating the combustion state of an internal-combustion engine, which comprises the following steps:

[0026] 1) if figure 1 As shown, a cylinder pressure sensor 2 is set in any sub-cylinder of the internal combustion engine 1 (for convenience of description, the sub-cylinder provided with the cylinder pressure sensor 2 is referred to as a reference cylinder hereinafter), and a crankshaft is set on the crankshaft of the internal combustion engine 1 Speed ​​sensor 3. In order to obtain measurement information in real time, an electronic control unit 4 for collecting the cylinder pressure signal of the cylinder pressure sensor 2 and the crankshaft speed signal of the crankshaft speed sensor 3 can also be set outside the internal combustion engine 1 .

[0027] 2) According to the rigid model of the c...