Fluid Pressure Control

FLUID PRESSURE CONTROL
VALVE BODY





The valve body with built-in valves to control fluid pressure is located in the oil pan. These valves are connected through fluid passages.

VALVE FUNCTION








Manual Valve
This valve switches the fluid passage. As it is connected with the shift lever at the driver's seat through a linkage, it selects a fluid passage corresponding to each range of "P", "R", "N", "D", "2", or "L" as selected by the shift lever.





Primary Regulator Valve
This valve controls the hydraulic pressure (line pressure) generated by the oil pump by using the throttle pressure, the line pressure when the gear is shifted to the "R" range and the spring force.
The hydraulic pressure generated by the oil pump (line pressure) is applied to (1 and (3 trying to lower the valve. On the other hand, the throttle pressure applied to (4 tries to raise the valve together with the spring force.
In this way, as the valve moves up and down, the line pressure is released through (2 so that it is adjusted according to the state of the throttle pressure. From (6 and (7), the hydraulic pressure is sent to the secondary regulator valve.
When the gear is shifted to the "R" range, as the hydraulic pressure is also applied to (5), increasing the force to raise the valve the hydraulic pressure (line pressure) is adjusted to a higher value than in any other range.





Secondary Regulator Valve
This valve controls the hydraulic pressure to the torque converter and the hydraulic pressure to be used for lubrication to each transmission parts.
The hydraulic pressure sent from the primary regulator valve is applied to (1 and (2), trying to lower the valve.
On the other hand, the throttle pressure through the primary regulator valve is applied to (3), trying to raise the valve together with the spring force.
In this way, as the valve moves up and down, the line pressure is released through (4) for pressure control. Hydraulic pressure is supplied to each part of the transmission from (5) for lubrication purpose.





Throttle Pressure Control Solenoid Valve
This valve regulates the throttle pressure with help of TCM which controls the electric current to the solenoid according to the throttle opening of the engine.
The hydraulic pressure (line pressure) applied to this valve (1) goes through the valve into the chamber (A), trying to lower the valve. The plunger of the solenoid controlled by TCM acts on the upper end of the valve trying to lower the valve.
On the other hand, the force of the spring located under the valve works against these two forces, trying to raise the valve.
As a result, the valve operates according to the throttle opening as described below to control the throttle pressure generated at (2).

When throttle opening is small
As TCM increases the amount of electric current supplied to the solenoid, the plunger moves down largely and the force to push the valve downward becomes larger. As a result, the valve lowers and the valve opening between (1) and (2) reduces, resulting in lower throttle pressure.

When throttle opening is large
As TCM reduces the amount of electric current supplied to the solenoid, the plunger moves less and the force to push the valve downward becomes smaller. As a result, the valve rises and the valve opening between (1) and (2) increases, resulting in higher throttle pressure.





Accumulator Control Valve
This valve controls the hydraulic pressure to each accumulator according to the throttle pressure.
As the throttle pressure applied to (2) increases, the valve moves to the left to control the line pressure (1) and the hydraulic pressure (3) rises. Conversely, as the throttle pressure applied to (2) reduces, the valve moves to the right to control the line pressure (1) and hydraulic pressure (3) drops.





Solenoid Modulator Valve
This valve depressurizes the hydraulic pressure (line pressure) generated by the oil pump and sends the fluid to the throttle pressure control solenoid. The hydraulic pressure (line pressure) applied to (2) passes the fluid passage in the valve into the chamber (A), trying to move the valve to the left. On the other hand, as a spring force to push the valve to the right is also applied to adjust the valve opening between (1) and (2), the depressurized hydraulic pressure acts on the throttle pressure control solenoid through (1).





1 - 2 Shift Valve
This valve switches between 1st and 2nd gears. It is subject to the spring force, hydraulic pressure (6)(force to push the valve to the left) and hydraulic pressure (3) (force to push the valve to the right) which is generated by operation of the shift solenoid No.2.
When in the 1st gear, as hydraulic pressure (line pressure) is applied to (3), the valve moves to the right and the hydraulic pressure (line pressure) applied to (4) is shut: off.
Also when the gear is shifted to "L" or "R" range, hydraulic pressure applied to (2) passes through the valve and (1) to cause the 1st & Rev brake to operate.
When in the 2nd gear, as hydraulic pressure (line pressure) is not applied to (3), the valve moves to the left. In this way, the hydraulic pressure applied to (4) passes through the valve and (5) to cause the 2nd & 4th brake to operate.





2 - 3 Shift Valve
This valve switches between 2nd and 3rd gears. It is subject to the spring force, hydraulic pressure (4) (force to push the valve to the left) and hydraulic pressure (5) (force to push the valve to the right) which is generated by operation of the shift solenoid No.1.
When in the 2nd gear, as hydraulic pressure (line pressure) is not applied to (5), this valve moves to the left and the hydraulic pressure applied to (3) is shut off.
When in the 3rd gear, as the hydraulic pressure (line pressure) is applied to (5), this valve moves to the right and the hydraulic pressure applied to (3) passes through the valve, (7) and 3-4 shift valve to be applied to the 2nd & 4th brake which is thus released.





3 - 4 Shift Valve
This valve switches between 3rd and 4th gears. It is subject to the spring force, hydraulic pressure (4) (force to push the valve to the left) and hydraulic pressure (1) (force to push the valve to the right) which is generated by operation of the shift solenoid No.2.
When in the 3rd gear, as hydraulic pressure (line pressure) is not applied to (1), this valve moves to the left and the hydraulic pressure applied to (2) passes through the valve, (8) and the coast clutch modulator valve to operate the coast clutch. Meantime, the hydraulic pressure is applied to (5) passes through the valve and (6) to be applied to the 2nd & 4th brake which is thus released.
When in the 4th gear, as hydraulic pressure (line pressure) is applied to (1), the valve moves to the right. In this way, the hydraulic pressure applied to (2) passes through the valve, (7) and the 3-4 shift valve to be applied to the 2nd & 4th brake which is thus engaged. Also, because the valve moves to the right, the fluid passages from (2) to (8) and from (5) to (6) are closed and the coast clutch is released.





2 - 3 Timing Valve
This valve adjusts the timing to switch the hydraulic pressure when the gear is shifted from the 2nd gear to the 3rd gear.





2nd and 4th Brake Modulator Valve
This valve adjusts the hydraulic pressure to the 2nd & 4th brake engagement side when the gear is in the 2nd, 3rd and 4th gears. As the line pressure is applied to (3) when in the 2nd and 4th gears, the valve is fixed at the upper position and the line pressure is transmitted as it is from (4) to (2).
When in the 3rd gear, as the line pressure is not applied to (3) and the valve is held by spring force, the hydraulic pressure (line pressure) applied to (4) is adjusted and transmitted to (2). As a result, the hydraulic pressures (1) and (2) that work on the second brake engagement side are adjusted at a higher level as compared with when in the 3rd gear.





2nd and 4th Brake Modulator Control Valve
This valve controls switching of the hydraulic pressure to the 2nd and 4th brake modulator valve when in the 2nd and 4th gears.
When in the 2nd gear, as the hydraulic pressure is not applied to (2), the valve moves up. The hydraulic pressure (line pressure) applied to (3) passes through the valve and (1) to act on the 2nd and 4th brake modulator valve.
When in the 4th gear, as the hydraulic pressure passes through (2), the valve moves down. Then the hydraulic pressure (line pressure) applied to (4) passes through the valve and (1) to act on the 2nd and 4th brake modulator valve.





Coast Clutch Modulator Valve
This valve adjusts the hydraulic pressure to the coast clutch when the gear is in the 1st, 2nd and 3rd and R ranges.
The hydraulic pressure (line pressure) coming through (2) passes the fluid passage in the valve, enters chamber (A) and pushes the valve downward. At the same time, however, as spring force pushes the valve upward, the hydraulic pressure is adjusted and applied through (1) to the coast clutch.





Low Coast Modulator Valve
This valve adjusts the hydraulic pressure to the 1st and Reverse brake when the gear is in the "L" range.
The hydraulic pressure is fed from the manual valve through (1) and after being adjusted in the valve, it is transmitted through (2) and 1 - 2 shift valve to the 1st and Reverse brake valve.





Forward Clutch Accumulator
This accumulator depressurizes the hydraulic pressure according to the state of the throttle when the forward clutch starts to operate. As the hydraulic pressure controlled according to the throttle conditions by the accumulator control valve is applied to (1) and (3), the hydraulic pressure applied to (4) is depressureized temporarily and then transmitted through (2) to the forward clutch.





Overdrive Clutch Accumulator
This accumulator depressurizes the hydraulic pressure according to the state of the throttle when the -tear is in the 3rd or 4rh gear and the overdrive clutch starts to operate.
As the hydraulic pressure controlled according to the throttle conditions by the accumulator control valve is applied to (1) and (3), the hydraulic pressure applied to (4) is depressureized temporarily and then acts on to the overdrive clutch through (2).





Reverse Clutch Accumulator
This accumulator depressurizes this hydraulic pressure according to the state of the throttle when the gear is in the "R" range and the reverse clutch starts to operate.
As the hydraulic pressure controlled according to the throttle conditions by the accumulator control valve is applied to (1), the hydraulic pressure applied to (3) is depressurized temporarily and then acts on to the reverse clutch through (2).





2nd and 4th Brake Accumulator
This accumulator depressurizes this hydraulic pressure according to the state of the throttle when the gear is in the 2nd or4th gear and the 2nd and 4th brake starts to operate.
As the hydraulic pressure controlled according to the throttle conditions by the accumulator control valve is applied to (1) and (3), the hydraulic pressure applied to (2) from the 2nd and 4th brake modulator valve is depressureized temporarily and then acts on the 2nd and 4th brake.





Pressure Relief Valve
When the line pressure generated by the oil pump exceeds the specified value, this valve relieves it to prevent it from growing excessively high.





TCC Control Valve
This valve switches the fluid passage to the torque converser crutch in the torque converter while running at a constant speed with the gear in the 3rd or 4th gear.
When TCC is working, the TCC control solenoid turns ON to allow the hydraulic pressure to be applied to (1) and the valve moves downward.
As a result, the hydraulic pressure applied to (3), passes through the fluid passage in the valve and is applied through (7) to the engagement side of TCC.





TCC Modulator Valve
This valve adjusts the hydraulic pressure which acts on the TCC control valve.
The hydraulic pressure applied to (2) passes through the fluid passage in the valve and enters chamber (A), trying to push the valve to the right.
At the same time, however, as a leftward spring force is working, the hydraulic pressure is adjusted and then transmitted through (1) to the TCC control valve and the TCC control solenoid.





TCC Control Solenoid Valve
This valve switches the hydraulic pressure to the TCC control valve. ON and OFF of the power to its solenoid is controlled by TCM.
When the solenoid is ON, as the plunger is pulled up to close the fluid passage, the hydraulic pressure applied to (1) is maintained and the TCC control valve moves down.
When the solenoid is OFF, as the plunger does not move and the fluid passage is open, the hydraulic pressure applied to (1) is relieved and the TCC control valve returns upward by the spring force.





Shift Solenoid Valve No.1
This valve switches the hydraulic pressure which acts on the 2 - 3 shift valve. ON and OFF of the power to the solenoid is controlled by TCM.
When the solenoid is ON, as the plunger is pulled up to open the fluid passage, the hydraulic pressures relieved and not applied to the 2 - 3 shift valve.
When the solenoid is OFF, as the plunger does not move and the fluid passage is closed to maintain the hydraulic pressure, the hydraulic pressure applied to (1) is then applied to the 2 - 3 shift valve.





Shift Solenoid Valve No.2
This valve switches the hydraulic pressure to the 1 - 2 shift valve and 3 - 4 shift valve. ON and OFF of the power to its solenoid is controlled by TCM.
When the solenoid is ON, as the plunger is pulled up to open the fluid passage, the hydraulic pressure is relieved and not applied to the 1 - 2 shift valve or 3 - 4 shift valve.
When the solenoid is OFF, as the plunger does not move and the fluid passage is closed to maintain the hydraulic pressure, the hydraulic pressure applied to (1) is then applied to the 1 - 2 shift valve and 3 - 4 shift valve.

FLUID PRESSURE OPERATION





1. "D" or "2" Range First Gear
The line pressure discharged from the oil pump is regulated by the primary regulator valve according to the throttle pressure controlled by the throttle pressure control solenoid valve and further regulated by the secondary regulator valve for lubrication of each part of the transmission. (This operation is applicable to all ranges.)
On the other hand, the line pressure, after acting on the manual valve, passes through the forward clutch accumulator and causes the forward clutch to engage. At this time, the accumulator temporarily depressurizes the line pressure to engage the forward clutch according to the throttle opening so as to reduce the shock caused when the forward clutch is engaged. Furthermore, as the shift solenoid valve No.1 is ON and the shift solenoid valve No.2 is OFF, the line pressure is applied to the right side of the 3 - 4 shift valve and the valve moves to the left. As a result, the line pressure, after acting on the 3 - 4 shift valve, passes through the coast clutch modulator valve, undergoes adjustment and causes the coast clutch to engage.





2. "D" or "2" Range Second Gear
The line pressure, after acting on the manual valve, passes through the forward clutch accumulator and causes the forward clutch to engage. Furthermore, as the shift solenoid valve No. 1 is ON and the shift solenoid valve No.2 is OFF, the line pressure is applied to the right side of the 3 - 4 shift valve and the valve moves to the left. As a result, the line pressure, after acting on the 3 - 4 shift valve, passes through the coast clutch modulator valve, undergoes adjustment and causes the coast clutch to engage.
Also, as the line pressure is not applied to the left side of the 1 - 2 shift valve, the valve moves to the left. As a result, the line pressure applied to the 1 - 2 shift valve passes through the valve and 2nd and 4th brake modulator valve, undergoes adjustment and then acts on the 2nd and 4th brake engagement side.





3. "D" Range Third Gear
The line pressure, after acting on the manual valve, passes through the forward clutch accumulator and causes the forward clutch to engage. Furthermore, as the shift solenoid valve No.1 is OFF and the shift solenoid valve No.2 is ON, the line pressure is not applied to the left side of the 3 - 4 shift valve and the valve moves to the left. As a result, the line pressure, after acting on the 3 - 4 shift valve, passes through the coast clutch modulator valve, undergoes adjustment and causes the coast clutch to engage.
Also, the 1 - 2 shift valve moves to the left with no line pressure applied to its left side and the 2 - 3 shift valve moves to the right with line pressure applied to its left side. As a result, the line pressure applied from the manual valve to the 1 - 2 shift valve passes through the valve, the 2 - 3 shift valve and the overdrive clutch accumulator to engage the overdrive clutch. At this time, the accumulator temporarily depressurizes temporarily the line pressure to engage the overdrive clutch according to the throttle opening so as to reduce the shock caused when the overdrive clutch is engaged.
Furthermore, the hydraulic pressure that has passed through the overdrive clutch accumulator passes through the 3 - 4 shift valve and works on the 2nd and 4th brake release side. On the other hand, with the 1 - 2 shift valve moved to the left, the line pressure applied to the 1 - 2 shift valve undergoes adjustment by the 2nd and 4th brake modulator valve and acts on the engagement side of the 2nd and 4th brake but the brake is released by the spring force of the brake and the hydraulic pressure working on the release side. When running at a constant speed, as the TCC control solenoid valve turns ON and the TCC control valve moves down, the hydraulic pressure coming from the primary regulator valve passes through the TCC control valve to operate the TCC.





4. "D" Range 4th Gear
The line pressure, after acting on the manual valve, passes through the forward clutch accumulator and causes the forward clutch to engage. Furthermore, with the shift solenoid valve No.1 turned OFF and the shift solenoid valve No.2 ON, the 1 - 2 shift valve moves to the left as its left side is free from the line pressure and the 2 - 3 shift valve moves to the right as its left side is subject to the line pressure.
As a result, the line pressure, after passing through the manual valve and acting on the 1 - 2 shift valve, passes through the valve and the 2nd and 4th brake modulator valve, works on the engagement side of the 2nd and 4th brake.
Also, the line pressure passing through the manual valve and acting on the 1 - 2 shift valve passes the 2 - 3 shift valve and overdrive clutch accumulator to cause the overdrive clutch to engage. When running at a constant speed, as the TCC control solenoid valve turns ON and the TCC control valve moves down, the hydraulic pressure coming from the primary regulator valve passes through the TCC control valve to operate the TCC.





5. "L" Range
The line pressure which acted on the manual valve passes through the forward clutch accumulator and causes the forward clutch to engage. At this time, the accumulator temporarily depressurizes the line pressure to engage the forward clutch according to the throttle opening so as to reduce the shock caused when the forward clutch is engaged.
Furthermore, with the shift solenoid valve No.1 turned ON and the shift solenoid valve No.2 OFF, the 3 - 4 shift valve moves to the left because its right side is subject to the line pressure. In this way, the line pressure which acted on the 3 - 4 shift valve, passes through the valve and the coast clutch modulator valve, to cause the coast clutch to engage.
Also, as the 1 - 2 shift valve moves to the right with the line pressure applied to its left side, the hydraulic pressure regulated in the low coast modulator valve passes through the 1 - 2 shift valve and causes the 1st and Reverse brake to engage.





6. "R" Range
The line pressure which acted on the manual valve passes through the reverse clutch accumulator and causes the reverse clutch to engage. At this time, the accumulator temporarily depressurizes the line pressure to engage the reverse clutch according to the throttle opening so as to reduce the shock caused when the reverse clutch is engaged.
Furthermore, with the shift solenoid valve No.1 turned ON and the shift solenoid valve No.2 OFF, the 1 - 2 shift valve moves to the right because its left side is subject to the line pressure and the 3 - 4 shift valve moves to the left because its left side is free from the line pressure.
In this way, the line pressure which passed through the manual valve and acted on the 1 - 2 shift valve passes through the valve and causes the 1st and Reverse brake to engage.
And the line pressure which acted on the 3 - 4 shift valve, passes through the valve and the coast clutch modulator valve, to cause the coast clutch to engage.