Electromotive throttle actuator

The electrical throttle valve actuator motor is attached to the intake air collector. The Digital Engine Electronics (DME) use this to calculate the position of the throttle valve:

• Position of the accelerator pedal module
• Torque request from other control units.

The Digital Motor Electronics (DME) opens or closes the electromotive throttle actuator electrically.

The throttle valve opening angle in the electromotive throttle actuator is monitored by 2 hall effect sensors.

The throttle valve is moved by an electric actuator motor. This servomotor is actuated by a pulse-width modulated signal with a frequency of 1000 Hz.

Fig 1: Identifying Throttle Valve Components

Courtesy of BMW OF NORTH AMERICA, INC.

The throttle valve has a mechanical adjustment range of 0 to 90°. The maximum position that is actually moved to is 81° (corresponds to 100 % throttle valve opening).

In the de-energized state, the throttle valve is held in the emergency running position of approx. 5.2° by 2 throttle return springs. These two springs also ensure that the throttle valve is returned to this position if a fault develops (activation deactivated). The Digital Motor Electronics (DME) uses the actual position measured to convert the required throttle valve opening setpoint into a signal.

The diagnosis monitors the two hall effect sensors. The electrical function (short circuit to ground, short circuit to B+ and line disconnection) and plausibility of the sensor signal are monitored.

The diagnosis runs continuously as soon as the following preconditions are satisfied:

• Terminal 15 on
• No electrical fault detected.

The Digital Motor Electronics (DME) receives a measured value of between 0 and 5 volts from the hall effect sensor. With the aid of the learned lower stop and a codable slope, the Digital Motor Electronics (DME) converts this voltage into the throttle valve opening angle. The diagnosis monitors the two signals with reference to a lower and upper voltage range.

Fig 2: Throttle Valve Characteristic Graph

Courtesy of BMW OF NORTH AMERICA, INC.