Engine

Abstract

An engine, according to exemplary embodiments, comprises: a cylinder having a cylinder bore; an intake valve for allowing air and fuel to flow into the cylinder bore; a piston accommodated to be slidable within the cylinder bore, and converting, into a linear driving force of the engine, an explosive force of exhaust gas generated when the fuel is combusted; an exhaust valve for discharging the exhaust gas generated from the cylinder bore; and a crankshaft connected with the piston and converting, into a rotational driving force of the engine, the linear driving force of the engine transmitted by the piston. The intake valve and the exhaust valve can be opened (overlapped) at the same time within a range of a rotational angle of the crankshaft of 3 to 12 degrees. Therefore, the engine, according to the exemplary embodiments, prevents a decrease in fuel efficiency while maintaining volumetric efficiency, and can satisfy exhaust gas regulations on CH4.

Description

technical field [0001] This invention relates to engines. In more detail, it relates to a natural gas engine. Background technique [0002] In most engines, there is an overlap in which the intake valve and the exhaust valve are opened at the same time. Generally speaking, the suction valve opens before the top dead center of the piston and closes after the bottom dead center, and the exhaust valve opens before the bottom dead center and closes after the top dead center. [0003] In particular, if the closing timing of the intake valve is early, the amount of the air-fuel mixture sucked in will decrease, and the volumetric efficiency will be low. If it is too late, the air-fuel mixture sucked into the cylinder will flow back to the suction port again, and the volumetric efficiency will decrease. . Also, if the closing timing of the exhaust valve is early, the exhaust gas cannot be exhausted sufficiently, and if it is too late, the exhaust gas flows backward from the exhau...

AI Technical Summary

Problems solved by technology

[0003] In particular, if the closing timing of the intake valve is early, the amount of the air-fuel mixture sucked in will decrease, and the volumetric efficiency will be low. If it is too late, the air-fuel mixture sucked into the cylinder will flow back to the suction port again, and the volumetric efficiency will decrease.

In addition, if the closing timing of the exhaust valve is too early, the exhaust gas cannot be exhausted sufficiently, and if it is too late, the exhaust gas will flow backward from the exhaust port into the cylinder, resulting in low volumetric efficiency.

In addition, the air-fuel mixture flowing into the intake port is not combusted, but is discharged through the exhaust port, which may result in poor fuel efficiency and failure to meet exhaust gas regulations for CH4 gas.

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