A method and system for reducing particulate matter emission during warm-up period of direct injection gasoline engine at low temperature

Abstract

The method and system designed by the present invention for reducing the discharge of particulate matter in the warm-up stage of a direct-injection gasoline engine at low temperature are characterized in that the atomization effect of fuel oil in the low-temperature warm-up stage is improved, and the generation of particulate matter is effectively reduced. Increase the fuel injection pressure, and take multiple (generally two) injections at the same time, shorten the time of each injection and reduce the penetration distance of the injection, thus avoiding the excessive fuel injection to the engine cylinder wall (or piston) after the pressure is increased. Risk of particulate matter and oil emulsification. The invention reduces the emission of particulate matter from the engine during the warm-up period under low-temperature and low-speed driving cycles, can effectively reduce the direct emission of particulate matter when there is no GPF, and can avoid the risk of GPF blockage in a short time (several low-temperature and low-speed driving cycles) when there is GPF , to reduce complaints from customers that they need to deliberately run high-speed carbon removal (to regenerate GPF).

Description

A method and the system technical field The invention belongs to the technical field of automobile control, specifically a kind of particle that reduces the warm-up stage of direct injection gasoline engine at low temperature method of discharge. Background technique With the implementation of the national 6 emission and fuel consumption regulations of passenger cars, the gasoline of the direct injection mode in the cylinder is mostly used in vehicle engines. Most of the direct injection gasoline engines are equipped with a particle catcher GPF (Gasoline Particle Filter) to achieve To meet the requirements of particulate emission regulatory targets, in low temperature (temperature below ‑15°C or lower), low speed driving environment, engine Just started, the water temperature is low, the gasoline volatility is low, the gasoline injected into the cylinder by a single injection is not well atomized, and it is not mixed with the air. If it is not fully burned, a lar...

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Problems solved by technology

[0002] With the implementation of National 6 emission and fuel consumption regulations for passenger cars, gasoline engines with in-cylinder direct injection are mostly used in vehicle engines, and direct injection gasoline engines are mostly installed with particle traps GPF (Gasoline Particle Filter) to achieve particulate matter emissions Requirements of regulatory objectives, low temperature (temperature lower than -15°C or lower), low speed driving environment, the engine just started, the water temperature is low, the volatility of gasoline is low, and the gasoline sprayed into the cylinder with a single injection is not atomized well. Insufficient mixing with air, insufficient combustion, forming a large amount of particulate matter, which is captured by the GPF. If several driving cycles have been driven at a lower speed, the temperature of the GPF is low (the regeneration temperature cannot be reached), and the GPF will Without good regeneration, particulate matter will quickly accumulate and block the GPF, affecting engine power output and driving experience, and even damage the engine in severe cases

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