System Description

ECM SIGNAL FUNCTION

Sensor

Input Signal to ECM

ECM function

Actuator

Camshaft position sensor (PHASE)

Engine speed⁽²⁾ Piston position

EGR volume control

EGR volume control valve

Crankshaft position sensor (POS)

Mass air flow sensor

Amount of intake air

Engine coolant temperature sensor

Engine coolant temperature

Throttle position sensor

Throttle position

Accelerator pedal position sensor

Accelerator pedal position

Park/neutral position (PNP) switch

Gear position

Battery

Battery voltage⁽²⁾

Air conditioner switch

Air conditioner operation ⁽¹⁾

Power steering pressure sensor

Power steering operation

Electrical load

Electrical load signal ⁽¹⁾

Wheel sensor

Vehicle speed ⁽¹⁾

TCM

Gear position, shifting signal ⁽¹⁾

⁽¹⁾	This signal is sent to the ECM through CAN communication line.

⁽²⁾	ECM determines the start signal status by the signals of engine speed and battery voltage.

This system controls flow rate of EGR led from exhaust manifold to intake manifold. The opening of the EGR bypass passage in the EGR volume control valve changes to control the flow rate. A built-in step motor moves the valve in steps corresponding to the ECM output pulses. The opening of the valve varies for optimum engine control. The optimum value stored in the ECM is determined by considering various engine conditions.

The EGR volume control valve remains closed under the following conditions.

Engine stopped
Engine starting
Engine idling
Low engine coolant temperature
Excessively high engine coolant temperature
High engine speed
Wide open throttle
Low battery voltage

Fig 1: EGR Function Diagram
Courtesy of NISSAN MOTOR CO., U.S.A.