240 L4-2127cc 2.1L SOHC Turbo B21FT FI (1982)
Altitude Compensator: Description and Operation
The regulator (applicable to B21FT turbo engine only) automatically adjusts the fuel injection pressure for different altitudes. The regulator increases
the injection fuel control pressure at higher altitudes to automatically compensate for the lower air density. This maintains the correct air/fuel ratio for
best engine performance and lowest possible emissions.
COMPONENT:
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Fig. 55 A.C.R PRESSURE REGULATOR
CONTROL PRESSURE REGULATOR INCORPORATING ALTITUDE COMPENSATING DEVICE
The amount of fuel which the engine can burn depends on the amount of oxygen supplied in the intake air. At high altitudes the oxygen content in the
air decreases, so the amount of fuel supplied to the engine must decrease in the same proportion. The control pressure regulator is affected by
atmospheric pressure. At high altitudes the pressure acting on the diaphragm in the regulator is less then at low altitudes, and the diaphragm
consequently takes up a higher position. This increases the spring force and the regulator closes slightly to result an increase in fuel control pressure, i.e.
a correct air/fuel mixture. Fig. 55.
NOTE:
The control pressure regulator is also controlled by temperature. This allows for a richer air/fuel mixture when the engine is warming up.
