CHERY AUTOMOBILE CO., LTD Automatic Transmission Fault Diagnosis Manual
Hydraulic control system
The hydraulic control system controls under following conditions:
1. The control handle’s position or main oil circuit’s pressure;
2. Accelerator pedal’s position or throttle oil pressure;
3. Vehicle speed or regulator oil pressure;
1. Shift valve
The shift valve controls the hydraulic liquid’s flow circuit in accordance with the control
handle’s position. The hydraulic oil arrives at the clutch and brake through the shift valve and
brake valve from the main oil circuit.
2. Oil pressure control valve (drain valve)
The oil pressure control valve opens when the oil pressure rises to certain value and the hydraulic
fluid flows back the oil pump’s suction chamber. The drain valve is different from relief valve
and is related with the regulator.
The hydraulic system on the main oil pressure control valve plate assembly has its oil pressure
on regulator, throttle, governor and torque converter all supplied by the main oil pressure.
3. Lubrication valve
verter relief valve
The torque converter’s relief valve limits the oil pressure inside the converter.
5. Governor
The governor simulates the engine’s output torque and controls the oil circuit pressure in the shift
elements at each gear. When gear shifted, the governor’s oil pressure is also adjusted accordingly.
When the engine’s output torque is low, the oil pressure inside the control element’s closed oil
circuit is also low;
When the engine’s output torque is high, the oil pressure inside the closed oil circuit is also high.
Since the engine’s rotation speed is low, the engine’s output torque is quite high, the governor must
Step down the accelerator pedal and the governor adjusts the throttle valve’s oil pressure.
2
nd
condition
When it is not necessary to increase the oil pressure, the regulator could work as a relief valve in
order to main continuous and stable oil pressure. The setup spring in the governor decides the oil
pressure. This condition only occurs when the governor’s plug arrives at the end point.
3
rd
condition
Step down the throttle pedal to full at a suitable ignition position and the governor’s oil pressure
could be reduced.
The hydraulic fluid enters into the transmission through the lubrication valve from the torque
converter.
4. Torque con
increase the oil pressure in the oil circuits of different control elements.
The governor works under three conditions:
1
st
condition
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