Method and device for engine exhaust gas recirculation

Abstract

The present application provides a method and device for exhaust gas recirculation of an engine. First, the first working parameter of the actual output of the engine and the second working parameter of the target output are obtained; then the deviation parameter is calculated according to the first working parameter and the second working parameter, and Judging whether the deviation parameter is less than the first threshold; when the deviation parameter is less than the first threshold, it means that the engine is working in a normal state, and the intake and exhaust gas ratio can be obtained directly according to the second operating parameter; when the deviation When the parameter is greater than the first threshold, it means that the engine is working in an abnormal state, and the intake-to-exhaust gas ratio can be obtained by combining the second working parameter and the deviation parameter. In this way, by comparing the difference between the theoretical output and the actual output of the engine, the working state of the engine can be judged, and different methods can be used to calculate the intake air exhaust gas ratio to control the exhaust gas recirculation of the engine, so that the exhaust gas recirculation system can also be used under abnormal engine operating conditions. works fine.

Description

technical field [0001] The present application relates to the technical field of engines, in particular to an engine exhaust gas recirculation method and device. Background technique [0002] Engine exhaust gas recirculation technology (Exhaust Gas Re-circulation, EGR) refers to returning part of the exhaust gas discharged from the engine to the intake manifold, and re-entering the cylinder together with the mixed gas. Since the exhaust gas contains a large amount of incombustible gases such as carbon dioxide, these gases have a high specific heat capacity and can absorb a large amount of heat, thereby reducing the maximum combustion temperature of the mixed gas in the cylinder, reducing the generation of nitrogen oxides, and reducing environmental pollution. pollute. [0003] At present, EGR technology calculates the EGR rate (intake-to-exhaust gas ratio, that is, the ratio of exhaust gas and mixture gas entering the cylinder) by calculating the theoretical output power or...

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Problems solved by technology

[0004] However, due to the aging of engine parts or the deterioration of fuel purity, the actual output torque or power of the engine cannot reach the theoretical output torque or power, but at this time the control system will still calculate and control the EGR rate according to the theoretical torque required, resulting in More exhaust gas entering the engine will cause the engine to stall, which has a greater potential for accidents

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