B23E Engine W/ Automatic Transmission (Canada Only)

Fig. 39 EXHAUST GAS RECIRCULATION SYSTEM (TYPICAL):

Exhaust Gas Recirculation System:

The exhaust gas recirculation system is used to reduce oxides of nitrogen (NOx) emitted from the engine exhaust. The formation of NOx occur at very high temperatures, during the peak temperature period of the combustion process. To control and reduce the amount of NOx, only a slight reduction in peak combustion temperature is necessary. This reduction is done by introducing small amounts of an inert gas into the combustion process. If too much inert gas is allowed into the combustion process (example stuck E.G.R. valve), the engine will idle roughly or not at all.
The engine exhaust provides a continuous supply of relatively inert gases that can be easily recirculated into the intake manifold. To recirculate these exhaust gases, a connection is made between the exhaust and intake manifolds. Fig. 39. and Fig. 156.


COMPONENTS:
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Fig. 40 E.G.R. VALVE:

E.G.R. VALVE
The E.G.R. valve is a vacuum activated shut-off and metering valve. It controls the flow of recirculated exhaust gases from the exhaust to the intake manifold. The valve is operated by engine vacuum. Fig. 40.

Fig. 41 THERMOSTAT:

THERMOSTAT
The thermostat allows vacuum to the E.G.R. valve only when the engine is hot. The wax-type thermostat is closed until the engine coolant temperature reaches around 60°C (140°F). Fig. 41.

Fig. 43 VACUUM AMPLIFIER:

VACUUM AMPLIFIER
The principal operation is based on utilization of venturi vacuum at the air cleaner. This venturi vacuum signal controls the vacuum amplifier which regulates the E.G.R. valve, to allow the correct amount of exhaust gas recirculation in relation to the intake air flow.
The vacuum amplifier receives two input vacuum signals, a weak venturi vacuum signal to be amplified and a strong manifold signal for its power source, to operate the E.G.R. valve. Fig. 43.

Fig. 45 E.G.R. REMINDER LIGHT:

E.G.R. REMINDER LIGHT
A reminder light will automatically come on every 15,000 miles (25,000 kilometers) to indicate that the E.G.R. system needs inspection. Fig. 45.