Control Valve

CONTROL VALVE

Component Location

Control Valve (Part 1):

Control Valve (Part 2):

Component Descriptions





Manual valve
The manual valve switches the hydraulic path for the line pressure generated by the oil pump.





When the selector lever is moved, the manual valve also moves, until it is located in a position where line pressure (7) is distributed to each line pressure circuit for each P, R, N position, and D, 2 and 1 range. Line pressures (1), (3), (5), and (6) are distributed to each valve. When line pressure (7) is not in a distribution position the line pressures (1), (3), (5) and (6) are drained at the X position.





1-2 Shift Valve
The 1-2 shift valve automatically shifts between first and second gear. The 1-2 shift valve switches the paths for the line pressure applied to the 1-2 shift valve. The shift solenoid A ON-OFF signal is controlled by the transaxle control module(or powertrain control module).





With shift solenoid A OFF, line pressure (12) is applied to the right side of the valve. This allows the valve to overcome line pressure (7) and the spring force, causing the valve to move to the left, shifting to first gear position. When vehicle speed is high, the transaxle control module(or powertrain control module) turns ON the shift solenoid A and line pressure (12) is drained from shift solenoid A. Consequently, spring force and line pressure (7) working on the left end of the valve push the valve to the right, shifting to second gear position. Even when line pressure (12) is drained, line pressure (7) does not change, due to there being an orifice. In second gear position, line pressure (1) is transmitted to (9), engaging the 2-4 brake band with a slow pressure increase by the orifice check valve and the 1-2 accumulator operation. Also, in 1 range, low reducing pressure (10) is transmitted to (11), engaging the low and reverse brake. In second gear position, low reducing pressure (11) is drained, releasing the low and reverse brake.

2-3 Shift Valve
The 2-3 shift valve automatically shifts between second and third gear.
The 2-3 shift valve switches the paths for the line pressure applied to the 2-3 shift valve. The shift solenoid B ON-OFF signal is controlled by the transaxle control module(or powertrain control module).





With shift solenoid B ON, line pressure (14) is drained from shift solenoid B. Consequently, spring force and line pressure (7) push the valve to the right, shifting to second gear position. In second gear position, line pressure (3) is closed and line pressure (13) is drained.
When vehicle speed is high, the transaxle control module(or powertrain control module) turns OFF the shift solenoid B. As a result, line pressure (14) is applied to the right side of the valve. This allows the valve to overcome line pressure (7) and the spring force, causing the valve to move left, shifting to third gear position.
In third gear position, line pressure (3) is transmitted to (13), applying the 3-4 clutch with a slow pressure increase by the bypass valve and the 2-3 accumulator operation.

3-4 Shift Valve
The 3-4 shift valve automatically shifts between third and fourth gear.
The 3-4 shift valve switches paths for line pressure applied to the 3-4 shift valve. The shift solenoid C ON-OFF signal is controlled by the transaxle control module(or powertrain control module).





With shift solenoid C OFF, line pressure (17) is applied to the right side of the valve. This allows the valve to overcome line pressure (7) and the spring force, causing the valve to move left, shifting to third gear position. In third gear position, line pressure (1) is transmitted to (16) and line pressure (13) is transmitted to (15). The line pressure (16) engages the coasting clutch through the orifice check ball. The line pressure (15) releases the 2-4 brake band. When vehicle speed is high, the transaxle control module(or powertrain control module) turns ON the shift solenoid C, allowing line pressure (17) to be drained from shift solenoid C. Consequently, the combination of spring force and line pressure (7) push the valve to the right side, shifting to fourth gear position. In fourth gear position, line pressure (15) and (16) are drained, engaging the 2-4 brake band and releasing coasting clutch.

Torque Converter Clutch Control Valve
The torque converter clutch control valve controls torque converter clutch operation based on the torque converter clutch solenoid valve ON-OFF signal which is controlled by the transaxle control module(or powertrain control module).





With the torque converter clutch solenoid valve OFF, line pressure (7) is applied to the right side of the valve. This allows the valve to overcome line pressure (1) and the spring force, causing the valve to move left. As a result, the hydraulic pressure (ATF) working on the torque converter front chamber passes from the torque converter clutch control valve, distributes the ATF, and inhibits torque converter clutch engagement. With the torque converter clutch solenoid valve ON, line pressure (7) is drained through the torque converter clutch solenoid valve. The combination of spring force and line pressure (1) push the valve to the right side. Consequently, the hydraulic pressure applied to the torque converter front chamber is drained through the valve, engaging torque converter clutch.

Throttle Valve
The throttle valve produces throttle pressure in relation to the depression of the accelerator pedal (engine output).





Depressing the accelerator pedal causes the throttle cam to turn, and as the throttle valve is pushed to the right by spring A, line pressure (7) is converted into throttle pressure (20). As the throttle pressure rises, it causes spring A to be compressed, and pushes the throttle valve back to the left. As this happens, line pressure (7) is closed to the throttle pressure (20) drains. Because the throttle valve is pushed to the right again by spring A throttle pressure (20) drops, line pressure (7) is opened, and throttle pressure (20) increases again. The throttle valve adjusts throttle pressure (20) by repeating this action. The force of spring A differs in accordance with the opening angle of the accelerator. For a large accelerator opening angle, the force of spring A is strong, and the high throttle pressure (20) is required to move the throttle valve. As a result, spring A creates a balance with high throttle pressure (20). Throttle pressure (20) also acts on the throttle plug, thereby maintaining the accelerator pedal feel.

Throttle Modulator Valve
The throttle modulator valve is a pressure-adjustment valve which produces throttle-modulated pressure from the throttle pressure.
This throttle-modulated pressure acts on the plug of the pressure regulator valve and pressure-adjusts the line pressure to match the throttle valve opening.





Throttle pressure (20) is applied to the right end of the throttle modulator valve. The combination of spring force and throttle pressure (20) push the valve to the left side. Throttle-modulated pressure (21) is applied to the left end of the valve, pushing the valve to the right side.
When throttle pressure (20) is high, the valve is pushed to the left, the drain port is closed, and throttle-modulated pressure (21) becomes higher. Then, when throttle-modulated pressure (21) is applied to the left end of the valve, the valve is returned to the left, the drain port opens, and throttle-modulated pressure (21) becomes lower.
With this action of the valve, throttle pressure (20) (combined with the spring force) and throttle modulated pressure (21) are balance to create throttle modulated pressure (21).

Pressure Regulator Valve
The oil pressure regulator valve adjusts the line pressure generated by the oil pump to match driving conditions.





Line pressure (7) that is generated in the oil pump works on chambers (A) and (B). The line pressure applied to chamber (A) moves the pressure regulator valves to the left side due to a difference between the surface areas of the two valves. Line pressure is then drained from chamber (C).
As a result, the pressure regulator valve balances at the point which the (A) chamber line pressure acting toward the left balances with the spring force and modifier pressure (21) acting toward the right side.
The line pressure (7) that works on chamber (A) becomes torque converter pressure (23) which is sent into the torque converter through the torque converter clutch control valve.
When the accelerator pedal is depressed, modifier pressure (21) rises adds to the spring force which moves the pressure regulator valve to the right side. This makes drainage of line pressure (7) from chamber (C) difficult; therefore, the pressure regulator valve balances at a high level line pressure (7). In R position, line pressure (6) is applied to the pressure regulator valve, moving the valve to the right. This makes drainage of line pressure (7) in chamber (C) difficult; therefore, the pressure regulator valve balances at a considerably high level line pressure (7).

Converter Relief Valve
The converter relief valve prevents torque converter pressure from exceeding a specified level.





Torque converter pressure (23) generated by the pressure regulator valve is constantly applied to the left end of the converter relief valve. It is spring force, however, which moves the valve to the left side. When torque converter pressure (23) increases, it overcomes spring force and pushes the converter relief valve to the right side. The pressure (23) is drained and maintained under a specified level.

Bypass valve
The bypass valve controls the 3-4 clutch engagement timing and shift shock to match the throttle valve opening.





The bypass valve is located parallel to the orifice check valve. The bypass valve is held closed by the spring and throttle-modulated pressure (21), and line pressure (13) is transmitted to (18). When line pressure (18) increases, in overcomes spring force and throttle-modulated pressure (21).The bypass valve moves to the left and closes line pressure (13). Line pressure (13) passes through the orifice check valve and the 3-4 engagement pressure is caused to gradually increase.

3-2 timing valve
The 3-2 timing valve controls the engagement timing of the 2-4 brake band to match the throttle valve opening.





The 3-2 timing valve is located parallel to the orifice, and controls the drainage of the 2-4 brake band release pressure.
Throttle pressure (20) is constantly applied to the right end of the 3-2 timing valve. It is spring force, however, which moves the valve to the right side.
When throttle pressure (20) is low, the valve closes the passage from line pressure (26) to (27). Line pressure (26) passes through the orifice and is drained slowly from the 2-3 shift valve.
When throttle pressure (20) increases, it overcomes spring force and pushes the 3-2 timing valve to the left side. The valve opens the passage from line pressure (26) to (27). Line pressure (26) passes through the orifice and the 3-2 timing valve and is drained quickly from the 2-3 shift valve.

Low Reducing Valve
The low reducing valve reduces low and reverse brake engagement pressure and capacity, thereby reducing shock when shifting from second gear to 1 range first gear.





The low reducing valve is normally pushed to the left side by spring force. When 1 range is selected, line pressure (5) is transmitted to low reducing pressure (10). Low reducing pressure (10) is then also applied to the left end of the valve, pushing it to the right side. As a result, the valve closes the passage from line pressure (5) to (10) and opens the drain port for low reducing pressure (10). Thus, low reducing pressure (10) is lowered. If low reducing pressure (10) decreases, allowing the valve to move to the left side by spring force the valve will close the drain port.

N-D Accumulator
The N-D accumulator moderates the rapid increase in hydraulic pressure during the forward clutch engagement. This reduces shift shock generated when D range is selected from N position.





In N position line pressure (7) is applied to the right end of the piston, pushing it to the left side. When D range is selected from the N position, line pressure (1), which engages the forward clutch, is applied to the left end of the piston. As a result, the combination of line pressure (1) and spring force overcomes the combination of line pressure (7) and spring force, moving the piston gradually to the right side. This movement of the piston moderates the rapid increase in line pressure (1).

N-R Accumulator
The N-R accumulator moderates the rapid increase in the hydraulic pressure during the reverse clutch engagement. This reduces shift shock generated when R position is selected from N position.





In N position, spring force pushes the piston to the left side. When R position is selected from N position, line pressure (6), which engages the reverse clutch, is applied to the left end of the piston. As a result, line pressure (6) overcomes spring force, moving the piston gradually to the right side. This movement of the piston moderates the rapid increase in line pressure (6).

1-2 Accumulator
The 1-2 accumulator moderates the rapid increase in hydraulic pressure during 2-4 brake band engagement. This reduces shift shock generated when shifting to second and fourth gear.





In first gear, line pressure (7) is applied to the right end of the piston, pushing it to the left side.
When shift solenoid A turns ON to shift to second gear, line pressure (9), which engages the 2-4 brake band, is applied to the left of the piston by the 1-2 shift valve. As a result, the combination of line pressure (9) and spring force overcomes line pressure (7), moving the piston gradually to the right side.
This movement of the piston moderates the rapid increase in line pressure (9).
When shifting from third gear to fourth gear, line pressure (9) is temporarily drained while still in third gear, the 2-4 brake band is newly applied, and then shifted to fourth gear. As a result, line pressure (7) and line pressure (18), which engages the 3-4 clutch, make the counteractive line pressure (9) shift high.
This provides optimal 2-4 brake band engagement timing during third to fourth gear shifting.

2-3 Accumulator
The 2-3 accumulator moderates the rapid increase in hydraulic pressure during the 3-4 clutch engagement. This reduces shift shock generated when shifting to third gear.





In second gear, line pressure (7) is applied to the right end of the piston, pushing it to the left side. When shift solenoid B turns OFF to shift to third gear, line pressure (18), which engages the 3-4 clutch, is applied to the left side of the piston by the 2-3 shift valve. As a result, the combination of line pressure (18) and spring force overcomes line pressure (7), moving the piston gradually to the right side. This movement of the piston moderates the rapid increase in pressure (18).