Exhaust Gas Recirculation (EGR) System (Mitsubishi Galant 5)

1. The exhaust gas recirculation (EGR) system is designed to reduce the content of nitrogen oxides in the exhaust gases. The EGR system recirculates part of the exhaust gases from the outlet pipe of the cylinder head to the pipe located on the intake manifold.

2. In one type of EGR system, the flow of recirculated gases is regulated by the EGR valve, an additional EGR valve (if installed) and a thermostatic valve (see illustration 13.1a).

a) The EGR valve is controlled by vacuum from the carburetor, which depends on the amount of throttle opening; the flow of recirculated gases at idle and wide open throttle is suspended.

b) The vacuum supplied to the EGR valve is controlled by a thermal valve which senses engine temperature. The thermal valve interrupts the vacuum supply to the EGR valve during warm-up when less NOx is produced and less recirculated gases provide better performance.

c) The additional EGR valve opens and closes together with the throttle valve by means of a lever mechanism, and regulates the flow of recirculated gases through the EGR valve depending on the position of the throttle valve.

3. In other types of EGR systems, an additional EGR valve is not used. A variable vacuum valve (VRV) is used to modulate the vacuum signal that is supplied to the EGR valve.

(The text of the article was taken from the website MITSUBISHIMAN.ru)