Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Off-Road Powertrain > Powershift Control and Shifting > Flashcards

Powershift Control and Shifting Flashcards

1
Q

Typical clutch application pressures range from

A

100 - 500 PSI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Typical Lube pressure

A

30-50 PSI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

TC relief valve

A

Located in parallel to the inlet of the TC, dumps directly bank to sump
Used to limit max pressure in the TC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Typical TC charge presure

A

50-125 PSI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Lube relief valve

A

Controls the max lube pressure, usually located after cooler and before oil get to lube components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the 4 pumps located in the powershift oil pump group

A

Transmission scavenging pump
TC/TD scavenging pump
Transmission charging pump
Steering and Brake lube pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Trans Shift Selector - Load piston

A

Controls the rate of pressure rise in the clutch pistons

Called shift modulation and is done to prevent shift shock, and clutch slippage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Trans Shift Selector - Pressure differential valve

A

Controls which clutch will apply first (F/R or 123)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

TC outlet relief valve

A

Limits the maximum working pressure in the TC. Spool is usually identical in size on both sides, so it has a pilot drilling to allow oil to enter opposite side of spring to create pressure diff.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Valve spring cavities

A

Almost all control spring cavities have a drain back to tank to prevent oil from getting trapped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Trans oil cooler

A

Long tubes inside for coolant to travel through is called straw type cooler
located following TC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The 3 hydraulic circuits in a basic shift control system are

A

Clutch application circuit
Converter charging circuit
Trans lube circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Oil flow for trans control system operation is supplied by

A

Charging pump driven at engine speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In a basic hydraulic shift control system, speed and direction changes are made by the

A

Shift selector valve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The function of the clutch pressure regulator valve is to

A

Limit the application pressure applied to the clutch pistons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The circuit that receives oil flow after the clutch application circuit has been satisfied is the

A

Converter charging circuit

17
Q

Maximum pressure in the TC is controlled by

A

TC relief valve

18
Q

What is the function of a trans scavenge pump (if equipped)

A

Remove leakage oil from the trans case

19
Q

Clutch modulation refers to

A

Controlling the build up of pressure in the clutch piston allowing controlled slippage of the clutch discs

20
Q

The factors that influence the point at which an automatic transmission shift are

A

Machine ground speed

Operator demand for power

21
Q

Modulator circuit

A

Is used to alter the shift points of the transmission in relation to the operator demand for power

22
Q

Modulator valve operation

A

When greater power demand is called for the cable moves tapered end reducing the spring pressure created in valve, this means instead of adding 50 psi (EX) to help governor it adds closer to zero meaning that vehicle speed has to be increased to raise governor pressure to make next upshift

23
Q

4 types of shift dampening devices

A

orifice control
modulation
trimmer
accumulator

24
Q

Orifice control shift dampening

A

Commonly used to control clutch release rates

placed in line between relay valve and sump to slow the rate at which springs push oil back

25
Q

Trimmer valve shift dampening

A

When pressure starts to develop in clutch a piston in valve moves allowing some oil to go to sump, as pressure move through orifice in piston, piston is pushed back up and sump port is blocked again continuing to fill clutch

26
Q

The function of the governor circuit in auto trans is

A

Provide a hydraulic signal that is proportional to machine ground speed

27
Q

Governor flyweights balance against what

A

Governor pressure

28
Q

How are shift point normally adjusted in auto trans

A

By varying the shift signal valve spring force

29
Q

The function of the modulator circuit is what

A

Provide a hydraulic signal that is proportional to the position of the engine throttle, this pressure is used to delay shift points when throttle is wide open

30
Q

4 functions of the ECU in an electronically controlled shift system

A

Control up and down shifts
Control clutch modulation
Provide diagnostic info
Provide warning to operator when malfunction occurs

31
Q

What output device is responsible for causing speed and direction changes

A

Shift solenoids

Off-Road Powertrain (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions