The function of the throttle valve is to close the intake duct when the engine is stopped. This results in strong damping of the "shut-off knock" (noticeable shaking of the engine). Vehicle comfort is thus improved.
- 1. Vacuum unit
- 2. Throttle valve shaft
- 3. Vacuum line from solenoid valve
The engine control unit actuates a solenoid valve (electro-pneumatic transducer), which then makes the vacuum connection in order to pneumatically close the throttle valve.
Diagram of Throttle Valve Actuation
- 1. Engine control unit (ECM)
- 2. Vacuum line
- 3. Solenoid valve (electro-pneumatic transducer)
- 4. Vacuum unit
- 5. Throttle valve
| V | Vacuum |