Stroke and compression ratio changing mechanism and control method thereof

Abstract

The invention provides a stroke and compression ratio changing mechanism and a control method thereof. The stroke and compression ratio changing mechanism is controlled by an engine control unit so asto adjust the piston stroke and compression ratio of an engine; the mechanism comprises a piston, a crankshaft, an eccentric shaft, an adjusting connecting rod, an executing connecting rod and a driving connecting rod, wherein the piston is slidably arranged in an engine cylinder, the crankshaft is rotationally arranged in the engine cylinder, the eccentric shaft is provided with an adjusting eccentric wheel, the adjusting connecting rod is rotationally arranged on a crank of the crankshaft, the executing connecting rod is hinged between one end of the adjusting connecting rod and the piston,and the driving connecting rod is hinged to the other end of the adjusting connecting rod; and the mechanism further comprises a swinging connecting rod, a controlling shaft rotationally arranged inthe engine cylinder and provided with a controlling eccentric wheel, a follow-up connecting rod and an eccentric shaft driving device. According to the stroke and compression ratio changing mechanism,the compression ratio and the piston stroke can be adjusted, and the performance of the engine can be improved.

Description

technical field [0001] The invention relates to the technical field of engines, in particular to a variable compression ratio mechanism with variable stroke, and also relates to a control method of the variable compression ratio mechanism with variable stroke. Background technique [0002] The four strokes of the piston and the compression ratio in the traditional gasoline engine are not variable, and it is difficult to meet the needs of the engine under different working conditions. As for the engine compression ratio, at low load, the compression ratio should be made larger to improve engine thermal efficiency and lower fuel consumption, while at high load, the compression ratio should be made smaller to suppress knocking. However, due to the invariable compression ratio of the traditional engine, it can only adopt a compromise solution for different loads, so that the above-mentioned effects cannot be obtained. For the piston stroke, if the expansion stroke is long, the ...

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Problems solved by technology

However, due to the invariable compression ratio of traditional engines, only compromise solutions can be adopted for different loads, so that the above effects cannot be obtained.

For the piston stroke, if the expansion stroke is long, the piston will work for a long time, and the engine will do more work. However, due to the existing crank and connecting rod structure, the piston expansion stroke and compression stroke of the traditional engine are the same, so it cannot be made longer

[0003] In order to improve the running performance of the engine under different loads, some automobile manufacturers have proposed a variable compression ratio technical solution. However, this variable compression ratio solution reduces the compression ratio in order to suppress knocking at high loads. However, the expansion ratio of the piston is also reduced, which leads to the short working time of the piston and the decrease of the thermal efficiency of the engine.

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