Automatic Transmissions Flashcards
What is the gearbox combined with to form an automatic transmission?
Torque converter
What is the main components of the automatic transmission?
Sun gear Planetary gears Planet carrier Annulus Brake bands
What happens to the annulus when the automatic gearbox is in neutral?
Planet gears turning anti clockwise and sun gear turning clockwise
What happens to the epicyclic gears when in low drive?
Annulus is locked , planet gears crawl inside annulus clockwise
What happens in the epicyclic gear when in direct drive?
Annulus locked to planet Carrier. Turns as a solid mass
How is the automatic gear selector connected to the gearbox
Rod or cable
What does the throttle have to quicken the gear changes?
Kick down
How does ECAT work?
Using electronically controlled solenoid valves that manage hydraulic pressure and therefore gear ratios
Advantages of ECAT?
Multiple shift patterns- sport ect
Driving modes saved- fail safe and limp mode
Smoother gear changes
Readily adaptable hydraulic control system
What inputs change gear on the ECAT?
Gearbox speed sensor
Gear selector
Kick down switch
Engine load sensor
What does the semi automatic transmission get rid of?
Clutch —-
Solenoid actuators or electric motors
Engine and transmission selector sensors - interpret gear changes
How many gear ratios does the CVT gearbox have?
Infinite
What controls forward and reverse on the CVT?
Two sets of multi plate clutches control epicyclic gear train
What alters the gear ratio on the CVT?
Primary pulley
How is the belt tension maintained on the CVT?
Varying the diameter of the secondary pulley
