The transmission control converts the driver’s shift requests into corresponding control signals to the clutch and the 5-speed automated manual transmission. This is done by relaying the shift signal about the shift request at the electronic selector lever module control unit over a direct line to the automated manual transmission control unit. The automated manual transmission control unit checks the plausibility of the shift request in relation to the vehicle speed, the load (accelerator pedal position) and the engine speed. If the plausibility check is passed, the automated manual transmission control unit sends the signal to initiate the selected shift operation to the two actuator motors for the two selector drums and to the clutch motor to open or close the clutch.
The automated manual transmission control unit controls the following functions depending on the input information:
• Engaging first gear at vehicle standstill
• Gear change
• Compulsory upshift just before maximum engine speed is reached
• Compulsory downshift when engine idle speed is approached
• Downshift for kickdown
• Disengaging the gear after 1 s when a door is opened without the service brake or accelerator pedal being actuated
• Crawl function
• Clutch operation
• Monitoring of clutch load
The automated manual transmission control unit directly reads the signals from the following components:
• Transmission rpm sensor (L2)
• Transmission motor 1 (M17/3)
• Transmission motor 2 (M17/4)
• Clutch motor (M18)
• Electronic selector lever module control unit (N15/5)
• Park pawl switch (S16/2)
This is probably more detail than necessary, especially if you are looking to buy a used transmission. The way Smart Car ingeniously used a computerized system which converted a standard shift transmission to automated shifts is a viable method of producing an automatic shifting transmission in itself.
When you want information on car and truck transmissions, we are the place to come, if you don’t see the information you desire, ask me in the comment box. If you came here looking for a replacement transmission, GotTransmissions.com has a full selection of replacement transmissions ready for immediate shipment. Call us now at 1-888-344-8044.