EGR Volume Control Valve
FUNCTIONS WITHIN THE SYSTEM
The EGR volume control valve utilizes a step motor to control the EGR flow rate from the exhaust manifold, and controls the valve opening depending on the driving condition in accordance with the command from the ECM.
INDIVIDUAL FUNCTION WITHIN THE SYSTEM
The EGR volume control valve controls the valve opening by turning the step motor on and off, and controls the EGR flow rate.
INDIVIDUAL OPERATION
EGR VOLUME CONTROL VALVE
The step motor of the EGR volume control valve consists of four coils facing each other. When the system 1 is turned on by the output signal from the ECM, the other system 1 of the same circuit is turned off. The valve is opened by changing the order in which the coils are energized, and the valve is closed by energizing in the reverse order. The valve is held in that position by energizing some of the four coils.
EGR VOLUME CONTROL VALVE POSITION SENSOR
The EGR volume control valve position sensor is built in the EGR volume control valve and uses a permanent magnet and a semiconductor device. This sensor measures valve shaft movements and transmits a voltage signal to ECM. Based on this signal, ECM judges the valve opening angle as of then and controls the motor to achieve opening angle appropriate to the driving conditions.
EGR TEMPERATURE SENSOR
The EGR temperature sensor detects temperature changes in the EGR passage. When the cooling efficiency of EGR cooler is extremely low, exhaust gas is not cooled than expected, and the temperature in the passage changes. The EGR temperature sensor is a thermistor that modifies a voltage signal transmitted from the ECM. This modified signal then returns to the ECM as an input signal. When the temperature increases, EGR temperature sensor resistance decreases.
Component Location
The EGR control valve is mounted on the exhaust side of the cylinder head.