A Method for Realizing the Atkinson Cycle of a Naturally Aspirated Gasoline Engine

Abstract

The invention provides a method for realizing the Atkinson cycle of a naturally aspirated gasoline engine, the method comprising: (1) adopting a high-energy ignition coil, the ignition energy of which is at least 80mJ; (2) integrating EGR on the intake manifold to stabilize the voltage The EGR system takes the exhaust gas from the outlet of the exhaust manifold, and enters the EGR pressure stabilizing cavity after passing through the EGR system. The exhaust gas is collected in the EGR stabilizing cavity and evenly distributed to each branch of the intake manifold; The air intake port matches the piston with a shallow pit on the top surface; (4) The intake camshaft adopts the variable valve phase system, and the intake valve phase adjustment angle is 58 ° crankshaft angle to realize the delayed closing of the intake valve, and the intake cam The maximum delayed closing angle of the shaft is more than 100 ° crankshaft angle after the bottom dead center to adjust the effective compression ratio of the engine. The method of the invention can effectively reduce low-load misfire rate, suppress high-load detonation, improve intermediate-load thermal efficiency, and improve combustion stability in all working conditions.

Description

technical field [0001] The invention relates to the technical field of internal combustion engines, in particular to a method for realizing the Atkinson cycle of a naturally aspirated gasoline engine. Background technique [0002] The fourth phase of the fuel consumption standard "GB 27999-2014 Passenger Car Fuel Consumption Evaluation Method and Index" will be implemented in 2020, requiring the average fuel consumption level of new passenger cars in my country to drop to about 5L / 100km by 2020, corresponding to carbon dioxide Emissions are around 120g / 100km. In addition, the "Parallel Management Measures for Average Fuel Consumption and New Energy Vehicle Credits of Passenger Vehicle Enterprises" came into effect on April 1, 2018, which supports and encourages hybrid and pure electric vehicles, and will reduce the fuel consumption of traditional automobile enterprises. punished. The Atkinson cycle engine technology used for hybrid power has the characteristics of high ther...

AI Technical Summary

Problems solved by technology

[0003] The Atkinson cycle is realized on the naturally aspirated gasoline engine, mainly through the late closing of the intake valve to achieve and increase the compression ratio. The late closing of the intake valve can adjust the effective compression ratio and also achieve the purpose of the expansion ratio being greater than the compression ratio. Late closing of the intake valve causes most of the oil and gas to flow back into the intake port and intake manifold, resulting in difficult control of the air-fuel ratio and unstable combustion

At present, if we only increase the compression ratio, increase the opening angle of the intake valve, and adjust the opening and closing time of the intake valve through the intake VVT, although the Atkinson cycle can be realized, it is difficult to ensure the stability of combustion, which will High load is easy to knock, low load is easy to catch fire, and the thermal efficiency of intermediate load is not high, and the final thermal efficiency is not significantly improved.

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