Electric supercharging non-backflow Atkinson cycle gasoline engine system

Abstract

The invention discloses an electric supercharging non-backflow Atkinson cycle gasoline engine system. According to the principle, the closing time of an air inlet door is advanced to the time before the bottom dead center of a suction stroke, so that an expansion ratio is greater than a compression ratio, and running of Atkinson cycle in a non-backflow working process is realized; air inlet pressure is controlled by an electric supercharger, dynamic property reduction caused by running of the Atkinson cycle is compensated, the stroke-bore ratio is large (greater than 1.3), and the potential of the Atkinson cycle for improvement of thermal efficiency is played fully; and under the working condition of high load, a valve throttling cooling effect can be formed by supercharged high-pressure inlet air to inhibit detonation. By the device, the advantage of fuel economy of an Atkinson cycle gasoline engine is played fully, meanwhile, the dynamic property of the Atkinson cycle gasoline engine is improved effectively, and an efficient working region is expanded; and if the electric supercharging non-backflow Atkinson cycle gasoline engine system is applied to a hybrid electric vehicle, requirements on load capacity of a motor and a battery can be reduced, and the cost of a hybrid power system is reduced.

Description

technical field [0001] The invention relates to the technical field of internal combustion engines, in particular to an electric supercharging non-return Atkinson cycle gasoline engine system. Background technique [0002] The Atkinson cycle gasoline engine introduces the concept that the expansion stroke is greater than the compression stroke, so that the combustion gas can be fully expanded so that the heat energy released by fuel combustion can be more fully utilized, which has become a key technology in hybrid electric vehicles. At present, the high expansion ratio gasoline engine of the hybrid electric vehicle realizes the Atkinson cycle through the late closing of the intake valve. It adds a backflow working process on the basis of the traditional gasoline engine working process. This backflow working process disturbs the formation of the tumble motion in the cylinder. As a result, the uniformity and turbulent intensity of the mixture in the cylinder are affected, and ...

AI Technical Summary

Problems solved by technology

At present, the high expansion ratio gasoline engine of the hybrid electric vehicle realizes the Atkinson cycle through the late closing of the intake valve. It adds a backflow working process on the basis of the traditional gasoline engine working process. This backflow working process disturbs the formation of the tumble motion in the cylinder. As a result, the uniformity and turbulence intensity of the mixed gas in the cylinder are affected, and the combustion efficiency and thermal efficiency are reduced; because the return gas is a combustible mixed gas, when it is injected into the cylinder again, it is difficult to accurately control the fuel injection amount of the next cycle due to the change of the return flow Reasonable control of the air-fuel ratio will have a serious impact on the control of combustion and exhaust emissions; at the same time, the closing of the intake valve too late will cause a large amount of gas that was originally entered into the cylinder to return to the intake manifold, increasing the loss of gas flow and reducing the The effective mixture charge in the cylinder reduces the mean effective pressure and weakens the power performance

[0003] Patent CN101201011 proposes an Atkinson cycle power system, which uses an electric supercharger to boost the intake air to compensate for the reduced torque output of the Atkinson cycle engine; however, the realization of the Atkinson cycle still uses the intake air Late door closing strategy, the intake valve is closed at least 60 degrees of crank angle after the bottom dead center position, which still includes the working process of backflow

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