Forming method of mixed gas of layered lean-burn spraying-wall face combined-guiding LPG direct injection supercharged engine

Abstract

The invention relates to a forming method of mixed gas of a layered lean-burn spraying-wall face combined-guiding LPG direct injection supercharged engine. The method is mainly characterized in that a large-inclination-angle bottom-face pit is formed in the top of a piston, the center of the pit deviates from the axis of a cylinder, and the symmetry axis (the bottom) of the pit deflects downward by 40 degrees in the anti-clockwise direction; three-hole spray nozzle high-pressure center injection is adopted, part of LPG is injected to the position close to a sparking plug electrode to directly form the combustible mixed gas in a spraying guiding mode at the later stage of the compression process, and the other part of fuel injected into the combustion chamber pit provided with the large-inclination-angle bottom face goes upward along with a piston to the position close to a sparking plug to form the combustible mixed gas in a wall-face guiding mode under the action of entrainment vortex and air intake vortex in the pit; under the partial load work condition, one air intake valve is closed, and air flow enters a cylinder only through the other air intake valve to form air intake vortex. Under the large load condition, the two air intake valves are opened at the same time, the air intake early stage ((70 degrees CA ATDC) LPG injection is adopted to form homogeneous mixed gas in the cylinder. Under the cold starting and turbine heating conditions, the air intake early stage LPG injection is also adopted. In comparison with an existing engine, the lean-burn limit (air-fuel ratio A / F > 60:1) of the layered mixed gas is further widened, and fuel consumption can be reduced by more than 10%. The method is also applicable to a layered lean-burn direct injection supercharged gasoline engine.

Description

technical field [0001] The present invention relates to a method for forming an air-fuel mixture of a spark ignition engine. Specifically, the electronically controlled in-cylinder direct-injection supercharged engine with LPG as fuel adopts the spray-wall compound guided fuel injection combustion chamber proposed by the present invention. layer structure; and in the case of heavy load, the mixed gas formation method using the pre-mixed homogeneous combustion method. Background technique [0002] LPG vehicles have the advantages of good cold start, and less PM and CO2 generated during combustion compared with gasoline and diesel. In today's low-carbon economy, it has become a current development trend to replace gasoline with LPG to reduce the effect of urban greenhouse gases, especially Suitable for city taxis with high daily mileage. But at present the research of spark ignition in-cylinder direct injection LPG engine still comes from the transformation of existing in-cy...

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Problems solved by technology

The method for forming the mixture of the above-mentioned "compound guide" LPG in-cylinder direct injection supercharged engine proposed by the present invention has not yet been seen

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