Component Description

Automatic Transmission - Electrical

Component Description

Clutch Motors

Two electrically commuted motors are used to actuate the double clutch in the transmission - one motor per clutch. The motors work independently of each other. When the clutch is fully closed, the motor provides the holding torque in addition with spring force. The clutch motors work against a clutch spring and are disengaged when they reach the zero position (rest position) with the spring force.

Input Shaft Speed Sensor

Input shaft speed sensor 1 measures the input speed and the rotating direction of the input shaft 1. The input shaft can be stationary. Therefore it is necessary, that the sensor system can detect the stationary state of the input shaft accurately. By being stationary the sensor must not indicate speed unequal to 0 (also not, if the motor runs by high speeds). The slow rolling of the car has to be detected safely.

Input shaft speed sensor 2 measures the input speed of the input shaft 2. The rotation direction is not measured.

Output Shaft Speed (OSS) Sensor

The OSS sensor measures the speed of the output shaft. The rotation direction is not measured.

The OSS sensor is located in the clutch housing above the differential.

The OSS sensor is an inductive sensor which detects the vehicle speed by means of an impulse ring on the differential.

The signal is used for the following functions among other things:
- to determine the shift timing.
- to supply the vehicle speed signal for the TCM (Transmission Control Module).

Shift Motors

Two electric motors are used to shift the gears in the transaxle, one motor for gears 1-3-5 and one motor for gears R-2-4-6. The gear shifting is made by two shift drums connected to shift motor pinion via two idler gears. The max shifting force is 1500N (337 lb). The motors are integrated in the TCM and work independently of each other.

Transmission Control Module (TCM)

The TCM (Transmission Control Module) is an assembly of an electronic module, sensors, and electrical actuators. It combines a control module and two electric motors for gear shifting. The primary function of the TCM (Transmission Control Module) is to collect incoming data signals, perform the interpretation of incoming data signals, communicate with the periphery and connect the electrical and mechanical contact to the signal transmitter and actuating elements. Vehicle and transmission interface is achieved via two connectors; vehicle and transmission connector. The transmission connector plug is located at the TCM (Transmission Control Module) and is the electrical connection between the TCM (Transmission Control Module) and the clutch actuators and the sensors. The vehicle connector is located at the TCM (Transmission Control Module) and is the electrical connection between TCM (Transmission Control Module) and the vehicle. The TCM (Transmission Control Module) is a programmable module.

Transmission Range (TR) Sensor

The TR (Transmission Range) sensor detects the position of the manual control lever shaft. The TR (Transmission Range) sensor is mounted on the transmission. The TR (Transmission Range) sensor allows the vehicle to start in PARK and NEUTRAL positions. The TR (Transmission Range) sensor output signal is linear over the measurement range and the TCM (Transmission Control Module) receives the selector lever position.