Urea solution metering injector and control method thereof

Abstract

The invention discloses a urea solution metering injector which comprises a pump, a urea cylinder, a step motor and a nozzle. An outlet of the urea cylinder is connected to an entry end of the pump sequentially through a pre-filter, a first volume-variable member and a first one-way valve, a discharge end of the pump is connected to the nozzle sequentially through a second one-way valve, a second volume-variable member and a filter, and the step motor is connected to the pump. A pressure valve is disposed between the filter and the nozzle. A sensor is disposed between the nozzle and the filter. The step motor is connected with a control unit which is connected with the sensor and the nozzle. The control unit is used for controlling pressure and starting time of urea solution from the nozzle according to the speed of the step motor. Each of the pre-filter, the filter, the first one-way valve, the second one-way valve, the pump and the step motor is provided with a heating unit.

Description

technical field [0001] The invention relates to a solution injection device and a control method thereof, in particular to a urea solution metering injection device and a control method thereof. Background technique [0002] Diesel engine is the model with the highest thermal efficiency, the best energy utilization rate and the most energy-saving model among various power machinery currently being industrialized. However, as the total amount of pollutant emissions continues to rise every year, the control of diesel engine pollutant emissions is imminent. Diesel engine emission standards set limits for harmful components in diesel engine exhaust gases such as hydrocarbons (HC), nitrogen oxides (NOX), carbon monoxide (CO) and particulate matter (PM), among which nitrogen oxides are very difficult to deal with. At present, the commonly used post-treatment methods of nitrogen oxides include selective catalytic reduction, selective catalytic reduction of hydrocarbons, nitrogen o...

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Problems solved by technology

The flow control of the urea solution is to obtain the pressure of the urea solution through the pressure sensor inside the urea solution supply system, and then control the flow of the urea solution by controlling the opening time of the nozzle, and the principle of the urea solution supply system is to use a plunger structure or a membrane Pump structure, this structure causes the pressure amplitude of urea solution to fluctuate greatly, especially in the case of small flow rate, it is difficult to accurately control the flow rate of urea solution

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