Operation Of Turbocharger; Waste Gate Valve; Intercooler - Toyota 7M-GE Repair Manual

Air
Cleaner
i
Operation of the Turbocharger
Valve
Intercooler
Air intake
Chamber
Exhaust gas.acts on the turbine wheel inside the
turbine housing, causing it to revolve. When the
turbine wheel revolves, the impeller wheel which is
located on the same shaft also revolves, com-
pressing the intake air which has passed through
the air flow meter from the air cleaner. When
expelled from the compressor housing the com-
pressed air is supplied to the cylinders. When the
engine speed increases, the exhaust gas volume
increases and the turbine wheel revolutions
increase (approx. 20,000 rpm - 110,000 rpm),
thus the turbocharged air pressure grows greater
and engine output increases.
I, Waste Gate Valve
Although on the one hand high output is
achieved by turbocharging, if the turbocharged air
pressure becomes too high, knocking occurs and
on the contrary, a reduction in engine output is
caused. If the turbocharged air pressure exceeds
the prescribed air pressure, the flow of exhaust
gas bypasses the turbine, controlling turbine wheel
revolutions and turbocharge air pressure. This by-
pass valve which controls the quantity of exhaust
gas flowing to the turbine is called the waste gate
valve.
When the supercharged air pressure exceeds
the prescribed pressure, the actuator operates, the
waste gate valve opens and part of the exhaust
gas by-passes the turbine. This causes a drop in
the turbine revolution rate and controls the
supercharged air within the prescribed limits.
Intercooler
The intercooler cools the turbocharged air
(intake air) put out by the turbocharger, thereby
increasing the air density. As the air intake efficien-
cy increases, the gas temperature in the combus-
tion chamber falls and the occurrence of knocking
is suppressed, giving an increase in engine output.
The Supra 7M-GTE intercooler is an air cooling
type located at the front of the vehicle, utilizing the
vehicle windstream to cool the turbocharged air.