Maxima SE V6-3.0L (VQ30DE) (1998)
Torque Converter Clutch Solenoid Valve Control
The torque converter clutch solenoid valve is controlled by the TCM. The plunger closes the drain circuit during the OFF period, and opens the circuit
during the ON period. If the percentage of OFF-time increases in one cycle, the pilot pressure drain time is reduced and pilot pressure remains high.
The torque converter clutch piston is designed to slip to adjust the ratio of ON-OFF, thereby reducing lock-up shock.
Torque converter clutch control valve operation
Lock-Up Released
The OFF-duration of the torque converter clutch solenoid valve is long, and pilot pressure is high. The pilot pressure pushes the end face of the torque
converter clutch control valve in combination with spring force to move the valve to the left. As a result, converter pressure is applied to chamber A
(torque converter clutch piston release side). Accordingly, the torque converter clutch piston remains unlocked.
Lock-Up Applied
When the OFF-duration of the torque converter clutch solenoid valve is short, pilot pressure drains and becomes low. Accordingly, the control valve
moves to the right by the pilot pressure of the other circuit and converter pressure. As a result, converter pressure is applied to chamber B, keeping the
torque converter clutch piston applied.
Also smooth lock-up is provided by transient application and release of the lock-up.
Overrun Clutch Control (Engine Brake Control)
Overrun clutch operating conditions
OVERRUN CLUTCH CONTROL (ENGINE BRAKE CONTROL)
Forward one-way clutch is used to reduce shifting shocks in downshifting operations. This clutch transmits engine torque to the wheels. However, drive
force from the wheels is not transmitted to the engine because the one-way clutch rotates idle. This means the engine brake is not effective.