Automatic transmission valves
Automatic transmissions use various valves to control the flow of hydraulic fluid through the system, resulting in gear changes. The main types of valves include:
1. Control valves
* Selector valve: Selects the gear selector position (P, R, N, D, D2, L).
* Throttle Control Valve: Controls the fluid pressure supplied to the transmission clutches.
2. Coupling valves
*Clutch Lock-Off Valve: Engages the transmission clutch, allowing fluid to flow through it.
*Clutch Release Valve: Releases the transmission clutch, blocking fluid flow.
* Shift Valve: Switches between gear clutches to determine which gear is engaged.
3. Timing valves
*Oil Pump Shift Valve: Directs fluid flow to the appropriate oil pump, ensuring sufficient pressure at various engine speeds.
* Gearbox Lockup Solenoid Shift Valve: Activates and deactivates the torque converter connecting the engine to the transmission.
4. Pressure control valves
* Pressure Regulator Valve: Regulates system operating pressure to ensure optimal gear shifting.
* Pressure reducing valve: reduces pressure in certain parts of the system, preventing damage.
5. Brake valves
* Brake Band Valve: Activated to keep gears locked.
* Freewheel Lock Valve: Releases the freewheels, allowing them to rotate freely.
6. Other valves
* Crankcase ventilation valve: regulates the pressure in the transmission crankcase.
* Cooling Valve: Directs coolant through the transmission to dissipate heat.
Automatic transmission valves are critical components in ensuring smooth and efficient gear shifting. Their correct operation is essential for optimal performance of the vehicle’s transmission.