柴油机冷EGR温度控制器的研究

为了降低柴油机NOx的排放量,设计了一种冷EGR温度控制器。该控制器可通过控制直流电动水泵的转速来调节冷却水的循环量,确保不同工况下的最佳EGR冷却温度。通过传感器信号获得EGR的冷却温度,如果EGR的冷却温度不在最佳冷却温度范围内,控制器通过PID控制改变脉宽调制信号PWM的占空比来调整水泵电机的平均电压以改变水泵的转速进而调节冷却水的循环量,从而实现冷EGR温度的自动控制。在CA498型柴油机上对该温度控制器进行了试验,结果表明,与未冷却的EGR系统相比,该冷EGR温度控制器可以有效地降低NOx的排放量。

Study on Cooling EGR Temperature Controller for Diesel Engine

In order to reduce the NOx emission quantity of diesel engine,an cooling EGR temperature controller was designed.The controller can control the revolving speed of a direct current electric pump.Through controlling the revolving speed of the direct current electric pump,the cooling water’s circulation was regulated.By the way of adjusting the circulation of cooling water,the EGR optimum cooling temperature range was ensured.The EGR cooling temperature was gained through temperature sensor,if the EGR cooling temperature was not within the optimum cooling temperature range,the temperature controller can adjust the average voltage of the electric water pump through changing PWM signals’ pulse duty factor.The water pump’s revolving speed was changed to regulate the circulation of cooling water.So the EGR cooling temperature was controlled automatically through the regulation of cooling water’s circulation.By applying the temperature controller in CA498 diesel engine,the test results show that comparing to the EGR system of without cooling EGR device,the cooling EGR temperature controller can reduce the quantity of NOx emission effectively.