Method for expanding and optimizing compression ignition operation range of internal combustion engine applying variable valves

Abstract

The invention provides a method for expanding and optimizing compression ignition operation range of an internal combustion engine applying variable valves. The internal combustion engine comprises intake valves, exhaust valves and electromagnetic full-variable valve devices, the intake valves and the exhaust valves are respectively provided with the electromagnetic full-variable valve devices forcontrolling the opening lift size and the opening phase angle of the intake valves and the exhaust valves; the electromagnetic full-variable valve devices drive the exhaust valves to open during an exhaust stroke period, so that exhaust gas starts to be discharged out of a cylinder; at some point of the exhaust stroke, the intake valves are driven to open, so that part of exhaust gas flows back into an intake manifold; and the lift for controlling the opening of the intake valves by the electromagnetic full-variable valve devices is decreased as the engine load is increased. According to themethod for expanding and optimizing compression ignition operation range of the internal combustion engine applying the variable valves, the small EGR rate can be adopted at high load to reduce severecombustion or knocking in the homogeneous compression ignition process, and the larger EGR rate can be adopted at low load to reduce incomplete combustion or misfire in the homogeneous compression ignition process, so that the homogeneous compression ignition operates in a larger operating range.

Description

technical field [0001] The invention relates to the technical field of internal combustion engines, in particular to an optimization method for expanding the compression ignition operating range of an internal combustion engine using a variable valve. Background technique [0002] As the form of environmental pollution becomes more and more serious, the emission regulations of internal combustion engines for vehicles are becoming more and more stringent. Among them, reducing the emission of nitrogen oxides from internal combustion engines is one of the key points to reduce harmful emissions from internal combustion engines. The homogeneous charge compression ignition technology (Homogeneous Charge Compression Ignition) applied to gasoline engines reintroduces or retains a part of the combustion exhaust gas in the cylinder, so that the overall temperature of the mixture rises, so that the spontaneous combustion of gasoline can be achieved at the top dead center of compression ...

AI Technical Summary

Problems solved by technology

[0003] However, compared with spark ignition engines, the operating range of homogeneous compression ignition is relatively narrow, which is mainly manifested in: compression ignition under high load will cause the fuel to burn too fast, which will cause engine knocking or violent combustion, while low load The fuel is scarcer, so the fuel burns slower, which leads to incomplete combustion or misfire

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