Fluid Coupling Torque Multiplication

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Fluid CouplingTorque Multiplication
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Torque converter purposes

• Allows vehicle to stop in gear
• Creates connection between engine and
  transmission
• When using locking converter a 11 link can be
  established
• Multiplies torque at low RPMs

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Basic components

• Turbine
• Impeller
• Stator with one-way clutch
• Pressure plate if lock-up

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Operation

• Impeller
• Part of housing bolted to flexplate
• Pumps fluid by centrifugal force
• Throws fluid out to contact turbine vanes

• Turbine
• Locked to input shaft
• Acted on by force of fluid
• Spins faster based on fluid force
• Can only obtain 90 of impeller speed unless
  lockup style

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Operation of stator

• Fluid flow can be re-directed to help impeller
  at lower speeds increasing torque of engine
• Fluid re-directing is performed by stator
• After torque multiplication is not desired stator
  overruns
• Defective one way clutch can cause lack of power
  at low or high rpm

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Stall speed

• Stall speed is the point when engine rpm is
  limited by fluid pressure on turbine
• Controlled by vane design and stator
• Too low stall speed can indicate stator problems
• Too high can indicate slipping trans.

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Torque converter facts

• Fluid for coupling is supplied by trans. pump
  through shaft
• Most of the heat is created in converter
• Usually just before cooler
• Not a serviceable unit
• Can hold 10 quarts of oil
• Converter housing often drives trans. oil pump
• Watch for loose bolts

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Converter lock-up

• Performed by mechanically linking turbine to
  housing
• Controlled with hydraulics and electronics
• Has friction surface with a dampening pressure
  plate
• Used to increase mileage by reducing 10 slip

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Lock-up problems

• Can stick on, causing stalling
• Can shutter on engagement
• Can cause chuggle
• Inop causing mileage complaints and or
  overheating trans.

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