torque converter Flashcards
what is the purpose of the split guide ring
is to prevent turbulence within the unit while it is in operation
scavenging pumps are used where
the housing and the transmission are on the same plane
rotary flow is also called
coupling phase
since the engine block and torque converter housing are structurally strong the engine mount design reduces the need to
check proper torque converter/engine alignment
when is torque multiplication achieved in a torque converter
whenever the impeller rotates faster than the turbine and the stator is stopped
fixed stators are
fixed in place does not rotate - usually splined to a sleeve - can never achieve rotary flow - single phase
what are the three types of variable capacity torque converters
multiple impellers - multiple turbine - variable pitch
what is a variable capacity torque converter
a unit that can increase or decrease the torque capacity within its own ratio range
cooler relief circuit
always connected to the converter outlet - removes heat and contamination
what are the functions of a torque divider
provide automatic clutching - multiply engine torque in accordance with output shaft load - absorb power train shock loads
what is another name of the impeller or pump on a torque converter
the pump element
rotary flow will create
low heat - high speed - low torque
when is the maximum ratio change in a torque converter achieved
at a stall condition
in a torque divider the internal gear is also connected to the
turbine
what is the converter phase
turbine is rotating slower than the impeller ( vortex flow )
what is another name for a impeller
a pump
what are the scavenging methods
gravity drain - scavenging pump -
what are the two types of stators
fixed and freewheeling
what component on a torque converter changes the kinetic energy of the fluid in motion to mechanical energy on the drive line or transmission
the turbine
when is the minimum ratio accomplished in a torque converter
when they achieve a 1:1 drive
how many phases or there in a torque converter
three
what is the reaction member of a torque converter
the stator
what are the two types of converter housings
wet and dry
where does the impeller receive torque from
the engine fly wheel
what is the arrangement called when the torque converter is not coupled to the engine flywheel
remote torque converter
gravity drains are used where
the torque converter housing is located above the transmission
never condemn a component based on the results of
a single test
when both impellers are locked together on a variable capacity multi impeller
high torque is created
how is volume controlled on a torque converter
physical size of the impeller - vane size and number of vanes and structure
in addition to engine mount design what also can accommodate slight differences in misalignment
rubber block tooth construction
what is a stage
the number of times oil is redirected before it returns to the impeller
when does the impeller of a torque converter start to move
whenever the flywheel of the engine is moving
what is a torque converter
it is a type of fluid coupling device with the addition of a third element the stator
lock up clutch
mechanically connects the turbine and impeller and eliminates the small amount of slippage for 1:1 drive
why are the vanes in the impeller angled
to increase force and accuracy of the fluid flow onto the vanes of the turbine element
how is velocity controlled in a torque converter
physical size of the torque converter - actual size of the vanes and angle of the vanes - speed of the impeller
what must you check after torque converter installation
crankshaft end play
in cold weather regardless of oil used - the transmission must always be
placed in neutral with the machine park brake applied before engine start up
what are the elements of a torque converter
the impeller - turbine and the stator
what are the disadvantages of fluid couplers
efficiency is lost due to slippage - heat generation - cannot increase or multiply torque
the converter pressure regulating valve
maintains working pressure within the converter - prevents cavitation and aeration - usually found on the converter outlet
how are multiple turbines connected in a variable capacity torque
by a overrunning clutch
stall tests are conducted with the transmission in
the highest gear
in a torque divider the flywheel is connected to the
sun gear and the impeller
when light work is required out of a multiple turbine converter
only one turbine is doing work
oil in a torque converter must be
reasonably light
what can cause overheating of a torque converter
plugged oil cooler - charge pump faulty - low oil level - high oil level
the exact amount of torque multiplication of a stator depends on
the angle of the vanes in the elements
what drives the torque converter output shaft
the turbine
what is a critical concern that must be considered when remote mount is used
proper drive line alignment between the engine and torque converter
the converter relief valve
protects the converter from excessive pressure due to cold weather plugged filter or restriction - can also be used as the main pressure control for the transmission
what are the three V’s in torque converter energy transfer
Velocity - Volume - Viscosity
when light work is required on a multi impeller
one impeller is released
what is the lock up phase
when the turbine and the impeller are locked together by a mechanical means
what can cause a low stall speed during a T/S test
a slipping stator or over running clutch
what is a torque divider
when a single stage torque converter and a planetary gear set are used to transmit power
in a torque divider the carrier ( planetary gear set ) is also connected to the
output shaft
what is the stator designed to do
change the direction of oil flow so that is assists in torque multiplication
when a torque converter has multiple impellers
one is attached to the flywheel and constantly driven - the other is freewheeling and controlled by a valve or electrical switch controlling a piston that locks it to the first impeller
what are the two types of oil flow in a torque converter during operation
rotary and vortex
in a high speed stall if the engine speed is higher than specifications
the torque converter might not be multiplying torque as required or the forward clutch in the transmission may be slipping
what is a stage
refers to the number of times oil strikes the turbine before it returns to the impeller ( normally classed as the number of turbines )
when is minimum torque created in a variable pitch stator
closed position
what principal do torque converters operate under
hydrodynamics
dry housing
do not have a PTO or any gearing - are sealed so no oil leaks into housing
what will happen during the stall condition
maximum torque multiplication and heat generation
freewheeling stators
have an overrunning clutch - turns freely with turbine rotation at coupling phase - stationary at the coupling phase - able to achieve rotary flow - used in a two phased torque converter
the charge pump for the torque converter
provides oil flow for the torque converter and transmission - is driven by the impeller or directly off the fly wheel
what is a phase
the relationship of the impeller and turbine relative to energy transfer
what is the coupling phase
turbine is rotating aprox the same speed as the impeller ( rotary flow )
what are the three phases
converter - coupling - lockup
wet housings
used to lubricate a gear train within the housing can have a PTO
vortex flow will create
high heat - low speed - high torque
when is maximum torque created in a variable pitch stator
open position
what is another name for vortex flow
converter phase
whenever the turbine is running at low speeds what type of slow is generated
vortex
when you are conducting specific tests on a torque converter in the stall condition
never allow the torque converter to remain in this condition for longer then absolutely necessary due to heat generation
what can help you isolate the problem when running tests
monitoring the heat of individual components at the same time
what are the two possible locations for a torque converter to be mounted
remote mount or engine mount
never conduct a stall test in
low gear - driveline/transmission damage can occur
when would there be the most slippage in a torque converter
at low speeds
whenever the turbine and impeller are rotating at the same speed
rotary flow is created
what is another name for engine mount torque converters
integral design
what are some advantages of a torque converter
no mechanical connection - shock absorption - gradual start up
