Variable-compression-ratio internal combustion engine with control modes capable of being switched and control method of internal combustion engine

Abstract

The invention discloses a variable-compression-ratio internal combustion engine with control modes capable of being switched and a control method of the internal combustion engine. The internal combustion engine and the control method of the internal combustion engine are characterized in that the compression ratio is variable, control is accurate, and responses are made in time. The internal combustion engine comprises a crankshaft, a connecting shaft, an auxiliary rod, an auxiliary arm, a compression ratio modulating mechanism, an air cylinder, a piston, a connecting rod connecting the crankshaft with the connecting shaft and a connecting rod body connecting the piston and the connecting shaft. The compression ratio modulating mechanism comprises a first hydraulic cylinder, a second hydraulic cylinder and an adjusting rod. A cylinder block of the first hydraulic cylinder is fixedly arranged. The end of a piston rod of the first hydraulic cylinder is hinged to the adjusting rod. The end of a cylinder block of the second hydraulic cylinder is hinged to an internal combustion engine body and the end of a piston rod of the second hydraulic cylinder is hinged to the adjusting rod. One end of the auxiliary rod is rotationally connected with the connecting shaft. One end of the auxiliary arm is hinged to the end, away from the connecting shaft, of the auxiliary rod through a first rotary shaft and the other end of the auxiliary arm is hinged to the adjusting rod through a second rotary shaft.

Description

technical field [0001] The invention relates to an internal combustion engine, in particular to a variable compression ratio internal combustion engine with a switchable control mode and a control method thereof. Background technique [0002] The compression ratio of an internal combustion engine refers to the ratio of the total volume of the cylinder before compression to the volume of the cylinder after compression (that is, the volume of the combustion chamber). The compression ratio is an important attribute of the internal combustion engine. A low compression ratio will reduce the thermal efficiency of the internal combustion engine and reduce fuel economy. Although a high compression ratio can improve thermal efficiency, it also increases the risk of knocking. The compression ratio of the currently widely used internal combustion engine is a single fixed value, which has the following problems: at high speeds, the ignition advance angle needs to be delayed to resist kn...

AI Technical Summary

Problems solved by technology

The compression ratio is an important attribute of the internal combustion engine. A low compression ratio will reduce the thermal efficiency of the internal combustion engine and reduce fuel economy. Although a high compression ratio can improve thermal efficiency, it also increases the risk of knocking

The compression ratio of the currently widely used internal combustion engine is a single fixed value, which has the following problems: at high speeds, the ignition advance angle needs to be delayed to resist knocking, and the properties of alternative fuels cannot be fully utilized (such as methanol’s medium and low-speed knock resistance is better than that of gasoline. , about equal to gasoline at high speed), poor emissions during warm-up, etc.; especially for supercharged internal combustion engines, because the compression ratio of supercharged internal combustion engines is lower than that of naturally aspirated internal combustion engines; During low-speed operation, the supercharging system will produce a phenomenon of supercharging lag. Only when the supercharged internal combustion engine accelerates to a certain speed, the supercharging system will play a role, thereby reducing the thermal efficiency of the supercharged internal combustion engine during low-speed operation. fuel economy

Although a variable compression ratio internal combustion engine solution has been developed in the current automotive internal combustion engines, it can solve the above-mentioned deficiencies in the fixed compression ratio internal combustion engines; but the common problem of the current variable compression ratio internal combustion engines is that the accuracy of the compression ratio adjustment control is not increased. or compression ratio adjustment response is slow

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