190303b torque converter fundamentals and service Flashcards
What are the three V’s pertaining to hydrodynamic drives?
Volume of oil, velocity of oil, Viscosity of oil used
What drives the torque converters Impeller? and what does it do?
The engine, it “throws oil” at the turbine to turn mechanical energy to hydraulic energy
What is the purpose of the turbine?
It is the output element which transmits torque to a driveline or transmission: it receives hydraulic energy from the impeller and converts it to mechanical energy
When condition is the torque converter most useful?
At stall, it creates the highest torque multiplication
What 3 things are an advantage to FLUID COUPLERS? and what the the disadvantages of a FLUID COUPLER?
advantages: no mechanical connection, shock absorption, gradual start up of load.
Disadvantages: efficiency is lost due to slippage, cannot have a true 1:1 ratio, creates heat
What component adds torque multiplication to a fluid coupler?
a stator
Name the two types of flow through a torque converter or fluid coupler? explain the flow?
Rotary flow: when the turbine and impeller are at the same speed (nearly) and it is in its “coupling phase”, oil flow is turning the same direction as the two coupled units
vortex flow: when the turbine is not moving and a “corkscrew” oil flow through the converter (or coupler) is creating its highest torque also called its “converter phase”
What does a split guide ring do?
Prevents turbulence within a converter while it is in operation (smooths flow of oil)
What does a stator actually due to create torque?
changes direction of oil flow
What effect do the angle of the blades have on torque multiplication?
it can change the amount of torque multiplication based on what the manufacture design is.
When is the most torque created in a converter? and what happens as speed increases?
At stall, as speed increases less torque is created
What are the two types of stator? and what effect would they have on torque and the amount of “phases” a converter can do?
A fixed stator, which creates only torque (single phase converter) so no true coupling phase could happen, a freewheeling stator (2 phase) allows both torque multiplication and a coupling phase
What are the 3 “phases” of a converter? and what is the flow through the converter?
converter phase (vortex flow), coupling phase (rotary flow) and lock up phase (mechanically locked with a clutch)
does a converter create a full 1:1 ratio?
no, unless coupled with a mechanical clutch
What positions create what with a freewheeling stator? in regardless to flow?
rotary flow : stator turning with impeller and turbine, vortex flow : stator stationary
What kind of variable capacity converters are there?
multiple impeller, multiple turbine, variable pitch stator
What components are required when using a multiple impeller variable capacity converter?
a piston and clutch to lock one impeller to the other
What component is required when using a multiple turbine type variable capacity converter? Explain its positions based on speed
an overrunning clutch, in slower speeds the clutch locks up and allows higher torque generation, when the impeller speeds up it allows the overrunning clutch to freewheel because it is now turning faster
What controls the vanes on a variable pitch stator? and what position of the vanes creates maximum torque?
a hydraulically operated bellcrank, open position does, closed creates the highest speed
What does the torque converter inlet relief do?
protects the converter during cold start ups, plugged filter or restriction in the system
What does the torque converter outlet relief do?
maintains the working pressure inside the converter, prevents cavitation and aeration, and helps keep oil in the converter
What defines an element in regards to torque converters?
A set of blades
What is a stage defined as?
The amount of times the oil strikes the turbine before it returns to the impeller
during a catastrophic converter failure what could potentially happen to the transmission lubrication circuit or inlet of the hydraulic system (in regards to a torque converter setup)
the oil cooler can potentially plug up with debris and not allow oil to the transmission lubrication circuit which can create issues with the transmission (lack of lubrication to shafts, gears and clutches)
What temperature is considered unsafe for transmission oil?
above 121 degrees celsius, or 250 degrees fahrenheit
what defines a dry type converter housing?
a dry housing does not have any pto drive gears or other forms of gearing, the converter is sealed.
What defines a wet type housing?
a wet type housing has drive gears that drive a pto, and are required to be lubricated, the converter itself may still be enclosed and not allowed to leak, but the housing surrounding it is “wet”
What is required for a wet housing? explain?
removal of lubrication oil from lubricating bearings on the pto drive gears, either from gravity drain, or a scavenge pump, or drag will affect torque converter operation, and it could potentially overheat
what kind of pump is a scavenge type pump?
a non-positive displacement pump, which produces no pressure, just sucks and removes oil back to sump
how much wood could a wood chuck chuck, if a wood chuck could chuck wood?
I have no friggen idea
what is a torque divider?
its a torque converter with a planetary gear set attached to it
What planetary gears are attached to which component of the converter?
Sun gear and impeller are attached together, the internal gear and turbine are attached together and the carrier is attached to the output shafts, stator is fixed to the housing
engine idling output shaft stalled causes what to happen to the planetary gears or a torque divider?
sun gear and impeller rotating normally, internal gear and turbine rotating in reverse, as there is no load on the output shaft, carrier is held (output shaft)
What causes machine to start moving?
resistance on the output shaft creates a resistance and allows the machine to start moving (rpm drop)
What happens when engine speed increases and the output shaft is still stalled on a torque divider?
reverse direction of the turbine starts creating maximum flow,
what is a phase?
a functional change
What creates a high stall speed?
slipping forward clutch, problem in the torque converter, internal leakage or cavitation or worn out seals, overfueling
What creates a low stall speed?
not producing proper torque, due to a slipping stator over running clutch (possibly backwards) plugged air filter
what can cause overheating?
operator error, over stalling, no downshifts plugged oil cooler (internal or external) radiator fan failure,
What is important when it comes to installing a new torque converter?
pre-lubrication as it may take a bit for lubrication to get to bearings right away
where are the two places you can mount a converter?
engine mount (integral) or remote (external)
why is crankshaft endplay important?
serious damage can occur is something isn’t right (shim on wrong side of bearing etc)
why shouldn’t you clean aluminum in a hot tank?
the chemical can eat away at the aluminum and destroy the soft material
What is a stationary reactor
A stator could be considered this, something that doesn’t move, and reacts to the forces acting upon it.
