Metering pump liquid release control device for aftertreatment system of internal combustion engine exhaust gas purification

Abstract

A metering pump liquid release control device for a post-treatment system for exhaust gas purification of an internal combustion engine, comprising a metering pump housing, a metering pump cylinder and a piston disposed in the cylinder; a push rod and a liquid release valve support rod are sequentially arranged above the piston , a liquid release valve and a cleaning rod; the cylinder body of the metering pump is provided with a piston running dead stop; the metering pump cylinder above the piston running dead stop is provided with a hollow slider and a hollow outer liquid Cavity body; the cylinder space between the upper part of the piston and the slider constitutes a metering chamber; the space between the slider and the lower part of the liquid release valve constitutes a temporary liquid storage chamber. The invention can greatly reduce the influence of external spraying-assisting air pressure, and can maintain the metering accuracy of the metering pump within a relatively large range of spraying-assisting air pressure. At the same time, due to the design of double outlet chambers and the functions of the push rod and the cleaning rod, the metering pump will not be damaged or affect normal operation due to urea crystallization, which greatly increases the practicability of the metering pump.

Description

technical field [0001] The invention relates to a liquid release control device for a metering pump, in particular to a liquid release control device for a metering pump in a post-treatment system for purifying exhaust gas of an internal combustion engine. Background technique [0002] At present, the urea injection system used for aftertreatment of diesel engines is mainly the air-assisted system, especially in the application of medium and heavy vehicles. The air-assisted urea injection system uses the brake compressed air on the vehicle as the air source. The usual practice is to lead the compressed air (injection aid air) to the urea metering pump, carry the urea liquid released from the metering pump to the nozzle, and finally spray it into the engine exhaust pipe. This arrangement often causes the metering of the metering pump to be disturbed and affected by the pressure of the spray-assisted air; the main reason is that the change in the pressure outside the release ...

AI Technical Summary

Problems solved by technology

The device adopts double liquid chamber and double valve design, one of the chambers has a variable volume. At the same time, the push rod is used to directly push the liquid release valve, and the cleaning rod is used to loosen the liquid outlet that may crystallize, which solves the contradiction between the opening and closing of the liquid release valve. , so that the metering pump can maintain good accuracy in a relatively large range of spray-assisted air pressure, and also solve a series of problems caused by the crystallization of urea solution

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