Air relative charge control method and device

Abstract

The invention provides an air relative charge control method and device which are applied to a vehicle with a variable compression ratio (VCR) engine. The method comprises the steps that according to the actual compression ratio of the VCR engine, a preset air inlet valve closing angle center value is determined; based on the preset air inlet valve closing angle center value and an actual air inlet valve closing angle center value, a target air inlet valve closing angle center value is determined; based on the actual compression ratio and the center value of the target air inlet valve closing angle center value, the conversion coefficient of the air relative charge is determined; and the actual air relative charge is determined according to the intake manifold pressure and the exhaust gas pressure of the VCR engine and the conversion coefficient, so that the air relative charge in an air cylinder can be accurately calculated under all operation conditions of the VCR engine, the error between the relative charge of the fresh air actually entering the air cylinder and the relative charge calculated by an electronic control unit of an automobile is reduced, and stable operation of the engine is guaranteed.

Description

technical field [0001] The invention relates to the technical field of vehicle control, in particular to a method and device for controlling air relative charge. Background technique [0002] As users gradually increase the power and economy requirements of automobiles, the performance requirements for engines, one of the important parts of automobiles, are also gradually increasing. Engines include traditional engines and variable compression ratio (Variable Compression Ratio, VCR) engines. VCR engines can reduce fuel consumption and improve emissions by controlling the actual compression ratio, thereby improving the power and economy of VCR engines. [0003] At present, the market uses the intake manifold absolute pressure (MAP) sensor to measure the air pressure change of the intake manifold to calculate the relative charge. However, since the VCR engine affects the parameters related to the intake manifold pressure, under all operating conditions of the VCR engine, if t...

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