Description & Operation
To lower the formation of oxides of nitrogen (NOx), it is necessary to reduce combustion chamber temperatures. This is accomplished by introducing exhaust gas into combustion chambers.
Exhaust gas is drawn into intake manifold through a stainless steel pipe and an Exhaust Gas Recirculation (EGR) valve. EGR action is governed by EGR controller. Other components include: Vacuum Switching Valve (VSV), coolant temperature sensing thermo switch, engine speed sensor and control lever position sensor which transforms control lever angle into a voltage output.
When EGR controller energizes VSV, vacuum opens EGR valve. When EGR controller is off, VSV is de-energized and EGR valve closes.