
TURBOCHARGER SYSTEM — Description
TC-3
[DIAGRAM showing turbocharger system components including: Turbocharger, Air Flow Meter, Air Cleaner, Turbine Wheel, Impeller Wheel, Intercooler, Air Intake Chamber, Actuator, Waste Gate Valve]
Operation of the Turbocharger
Exhaust gas acts on the turbine wheel inside the turbine housing, causing it to revolve. When the turbine revolves, the impeller wheel which is located on the same shaft also revolves, compressing the intake air which has passed through the air flow meter from the air cleaner. When expelled from the impeller wheel, this compressed air passes on 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.
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 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 efficiency increases, the gas temperature in the combustion chamber falls and the occurrence of knocking is suppressed giving an increase 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.