EGR System: Description

The Exhaust Gas Recirculation (EGR) system is used for the reduction of NOx emissions by lowering combustion temperatures. Recycling metered amounts of exhaust gas back into the intake system lowers combustion temperatures.

Each system has a vacuum-operated EGR valve and a vacuum modulator. Temperature sensing devices control EGR operation.

Temperature sensing device used could be a Vacuum Switching Valve (VSV), a Bi-metallic Vacuum Switching Valve (BVSV), a Thermostatic Vacuum Switching Valve (TVSV), Vacuum Control Valve (VCV) or a combination of these valves. A check valve, EGR cooler and computer may also be used on some models.