Mazda 6 MPS 2005, Training Manual Supplement

Page: 45 / 112

Engine L3 Turbo
Wastegate operation
•
The wastegate controls the exhaust pressure on the exhaust side turbine, thereby
controlling the speed of the intake turbine.
•
The wastegate is operated using a diaphragm-type actuator.The overpressure to operate
the diaphragm is produced by the intake turbine.
•
As long as the wastegate control solenoid valve, which is controlled by the PCM, is
closed, the wastegate will be opened by the overpressure of approx. 0.7 bar.
•
If the wastegate solenoid is opened by the PCM, the wastegate cannot open any more,
because the overpressure sent to the actuator is leaking through the wastegate control
solenoid valve to the intake system.
•
Though, the wastegate control solenoid valve can inhibit the opening of the wastgate.
•
To control charge air pressure exactly the PCM operates the wastegate solenoid with a
duty signal.
•
To reduce the pressure loss when the wastegate solenoid valve is opened, there is an
orifice in the pressure pipe to the wastegate actuator.
M6-MPS_01056
1 Wastegate control solenoid valve 6 To WU-Catalyst
2 Orifice 7 Wastegate
3 To charge air cooler 8 Wastegate control diaphragm
4 From air cleaner 9 Air flow
5 Turbine
Service Training Mazda6 MPS Supplement 01-27