Ase 251 automatic transmission

1. ASE 251 Automatic Transmission/Transaxle Diagnosis and Service
Torque Converter Fundamentals
Jason Daves
Arapahoe Community College
Automotive Technology Department
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ASE 251 Arapahoe Community College Automotive Technology

2. Lesson Objectives
Upon completion of this presentation, you should be able to:
Identify the major components of a torque converter and explain their purpose.
Understand the fluid flows that occur in a torque converter.
Discuss stator design and operation.
Explain torque converter operation in the stall and coupling phases.
Explain torque converter clutch design and operation.
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3. Torque Converter Assembly
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4. Torque Converter Functions
The torque converter supplies a fluid coupling between the transmission and the engine.
It is similar to the clutch in a manual transmission or transaxle.
It allows the engine to continue to run while the vehicle is stopped without killing the engine
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5. Torque Converter Functions
It also multiplies torque at slower speeds to assist the engine in propelling the vehicle.
With the addition of a torque converter clutch, the torque converter allows for a mechanical link between the engine and the transmission.
The torque converter bolts to the flex plate and drives the transmission input shaft.
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6. Torque Converter Components
Housing
The torque converter housing holds all of the other components of the torque converter.

One end is bolted to the flex plate.

7. The other end is used to drive the transmission fluid pump. 8. The torque converter hub is machined to allow for a seal between the transmission oil pump and the hub. 9. It is usually made up of two pieces and welded together.ASE 251 Arapahoe Community College Automotive Technology
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10. Impeller

The impeller is driven by the engine, through the torque converter housing.

11. The impeller has many thin metal fins or blades similar to a fan. 12. These fins spins around in Automatic Transmission Fluid and force it away from the impeller like air from a fan. 13. Fluid from the impeller is directed to the blades of the turbine which is splined to the input shaft of the transmission.ASE 251 Arapahoe Community College Automotive Technology
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14. Turbine

The turbine is splined to the input shaft of the transmission.

15. The turbine receives fluid directed from the impeller. 16. As the fluid hits the blades of the turbine, it forces the turbine to rotate. 17. The input shaft which is splined to the turbine, rotates at the same time.ASE 251 Arapahoe Community College Automotive Technology
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18. Stator

The stator is located between the impeller and the turbine.

19. The stator helps to redirect the fluid from the turbine back to the impeller so that the process can begin all over again. 20. The stator is mounted on a one way clutch, so that is cant fight the correct flow of fluid inside the converter. 21. The stator helps to achieve vortex flow of fluid inside the transmission which is where torque multiplication occurs.ASE 251 Arapahoe Community College Automotive Technology
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22. Torque Converter Clutch

The torque converter clutch forms a mechanical link between the transmission input shaft and the engine.

23. Fluid coupling from the converter is only about 90% efficient at best. 24. When the vehicle is at cruise and the torque converter is in coupling phase, there is an inherent 10% slip between the TC and the engine. 25. A TCC is inside the TC housing and can be forced against the housing to remove the 10% slip rate.ASE 251 Arapahoe Community College Automotive Technology
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26. Torque Converter Stall
Torque converter stall is when the impeller is spinning while the turbine is held stationary.
Its good to have stall in the TCC because without it, your vehicle would die every time you came to a stop.
Stall speed is the highest rpm the impeller can move before the turbine must move.
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27. Coupling Phase
When the speed of the turbine is nearly equal to the speed of the impeller
The motion of the fluid during the coupling phase is called rotary flow.
During rotary flow efficiency approaches 90% and slipping is held to a minimum.
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28. Summary and Additional Information
Torque Converter operation
Torque converter components
Fluid coupling and fluid flow
Torque converter clutch operation
Additional Information
Torque Converter Youtube
Torque Converter Function Video
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29. Sources
Erjavec, Jack. Automatic Transmissions and Transaxles 4th Edition. Thompson Delmar Learning. 2007
http://www.youtube.com/watch?v=LEFWO3M4XOA. March 2010
http://www.youtube.com/watch?v=MvLoX0z9qoY. March 2010
Thank you for watching.
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Ase 251 automatic transmission

Automotive

Transcript of Ase 251 automatic transmission