Control method and system for gasoline engine excess air coefficient combustion

Abstract

The invention discloses a control method and system for gasoline engine excess air coefficient combustion. The control method for gasoline engine excess air coefficient combustion comprises the steps that the operation condition of an engine is monitored; the current load state of the engine is judged according to the operation condition of the engine, wherein load states of the engine comprise the partial load state, the large load state and the full load state; a matched excess air coefficient combustion mode is selected according to the current load state of the engine, wherein a lean combustion mode with the excess air coefficient being 1.6-2.0 is adopted for the engine when the current load state of the engine is the partial load state; a combustion mode with the excess air coefficient being 1 is adopted for the engine when the current load state of the engine is the large load state; and a combustion mode with the excess air coefficient being 0.8-0.9 is adopted for the engine when the current load state of the engine is the full load state.

Description

technical field [0001] The invention relates to the technical field of engines, in particular to a combustion control method and a combustion control system for a gasoline engine with an excess air ratio. Background technique [0002] Homogeneous Charging Compression Ignition (HCCI) control technology achieves low-temperature lean combustion by controlling the intake air temperature, and adopts pre-mixed, compression-ignited combustion methods, which effectively improves the effective thermal efficiency of the engine and reduces pollutants emission. However, since the intake air temperature is difficult to control precisely, and as the engine load increases, the sensitivity of compression ignition to intake air temperature increases significantly, and slight temperature control differences will lead to large changes in compression ignition, which will eventually lead to HCCI The combustion start point and heat release rate of the control technology cannot be controlled; at ...

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Problems solved by technology

However, since the intake air temperature is difficult to control precisely, and as the engine load increases, the sensitivity of compression ignition to intake air temperature increases significantly, and slight temperature control differences will lead to large changes in compression ignition, which will eventually lead to HCCI The combustion starting point and heat release rate of the control technology cannot be controlled; at the same time, the increase in engine load will also cause a sharp increase in the rate of combustion pressure increase, resulting in an uncontrollable and abnormal combustion process similar to knocking

[0003] In the existing gasoline engine combustion control technology, gasoline and air are usually mixed and burned at the stoichiometric air-fuel ratio. The excess air coefficient will not change with the change of engine operating conditions (load conditions), and it is difficult to effectively improve the thermal efficiency of the engine by utilizing lean combustion. The advantages

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