Method and system for improving FPLG combustion heat efficiency based on constant-volume combustion

Abstract

The invention provides a method and system for improving FPLG combustion heat efficiency based on constant-volume combustion. The method comprises the steps: in a stroke stage from a top dead center to a peak pressure generation position, after a rotor moves to the top dead center, a motor applies an electromagnetic force of a certain value, wherein the value of the electromagnetic force cannot begreater than the in-cylinder pressure, and the direction of the electromagnetic force is opposite to the in-cylinder pressure; therefore, the retention time of the rotor near the top dead center is prolonged, namely the constant-volume combustion time is prolonged. According to the technical scheme, the magnitude and waveform of the electromagnetic force are controlled in a segmented mode, the constant-volume combustion proportion of the engine can be increased under the condition that other conditions are not changed, and then the combustion heat efficiency of the engine is improved.

Description

technical field [0001] The disclosure belongs to the technical field of range extenders for new energy vehicles, and in particular relates to a method and system for improving the thermal efficiency of FPLG combustion based on constant volume combustion, so as to ensure that the engine can achieve constant volume combustion as much as possible. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] The free-piston linear generator (FPLG) converts the heat energy generated by the combustion engine into electrical energy output through the motor, which can replace the auxiliary power unit (APU) of the range-extended hybrid electric vehicle. As an emerging power device, the free-piston linear generator is An important research direction of the future new energy vehicle power system. [0004] The internal combustion engine in the FPLG system has si...

AI Technical Summary

Problems solved by technology

However, because FPLG lacks the flywheel to store energy, the movement characteristics of the mover completely depend on the force during the movement process. After the combustion start point and before the top dead center, it is affected by the compression and combustion gas pressure, and the speed quickly drops to zero. After the top dead center , affected by the pressure of the combustion gas, the mover moves in the opposite direction with a greater acceleration, so the stay time of the mover is shorter near the top dead center

It can be seen from the principle of internal combustion engine that when the gasoline engine burns at a constant volume, the thermal efficiency of combustion is high, and the constant volume combustion requires that the combustion is almost completed near the top dead center. However, due to the short residence time of the FPLG engine near the top dead center, the constant volume combustion may be poor. Therefore, the advantages of FPLG cannot be brought into play

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