572Main pressure regulator valve MPRV Fig 514a and b

This valve controls the output pressure which is delivered to the brake band, multiplate brake and clutch servos. Oil pressure from the pump acts on the left hand end of the valve and opposes the return spring. This oil pressure moves the valve to the right, initially permitting oil to pass to the converter pressure valve and its circuit, but with further valve movement oil will be exhausted back to the pump intake passage. The line pressure build-up is also controlled by introducing limited throttle pressure into the regulator spring chamber

TPLV

MPLV

MPRV

2GBS

Line or reduced line pressure from maoual valve

It Oil relief

Line or reduced line pressure from maoual valve

It Oil relief

fa) Pressure regulation (b) Pressure relief

Fig. 5.14(a and b) Main pressure regulating valve (MPRV)

fa) Pressure regulation (b) Pressure relief

Fig. 5.14(a and b) Main pressure regulating valve (MPRV)

which assists the spring in opposing the valve moving to the right. In addition, oil pressure from the manual valve passage, indirectly controlled by the governor, is imposed on the left hand end of the regulator valve. This modifies the valve movement to suit the various gear train and road condition requirements.

5.7.3 Throttle pressure valve (TPV) (Fig. 5.15(a and b))

The throttle pressure valve transmits regulated pressure based on engine throttle position. Opening or closing the engine throttle moves the kick-down valve spool so that the throttle valve spring tension is varied. The amount of intermediate pressure allowed through the throttle pressure valve is determined by the compression of the spring. The reduced pressure on the output side of the throttle valve is then known as throttle pressure. Throttle pressure is directed to the main pressure limiting valve, the kickdown valve, and to one end of the shift valves in opposition to governor pressure, which acts on the other end of the shift valves controlling upshift and downshift speeds.

5.7.4 Main pressure limiting valve (MPLV)

This valve is designed to limit or even cut off the variable throttle pressure passing through to the main regulating valve and the soft engagement valve. The pressure passing out from the valve to the main pressure regulator valve is known as limited throttle pressure. As the pressure passes through the valve it reacts on the left hand end of the main pressure limiting valve so that the valve will progressively move to the right, until at some predetermined pressure the valve will close the throttle pressure port feeding the main pressure regulating valve circuit.

When the throttle pressure port closes, the high pressure in the regulator spring chamber is permitted to return to the throttle pressure circuit via the non-return ball valve.

Fig. 5.15(a and b) Kickdown valve (KDV), throttle pressure valve (TPV) and valve for first gear manual range (1GMR)

5.7.5 Converter pressure valve (CPV) (Fig. 5.17) This valve shuts off the oil supply to the torque converter once the delivery pressure reaches 6 bar. Line pressure from the main pressure regulator valve passes through the valve to the torque converter and acts on its right hand end until the preset pressure is reached. At this point the valve is pushed back against its spring, closing off the oil supply to the torque converter until the converter pressure is reduced again.

The force on the output side of the converter pressure valve feeding into the converter is known as converter pressure.

5.7.6 Converter check valve (CCV)

This valve, which is located inside the stator support, prevents the converter oil drainage when the vehicle is stationary with the engine switched off. This valve is not shown in the diagrams.

5.7.7 Throttle pressure limiting valve (TPLV)

This valve converts line pressure, supplied by the pump and controlled by the main pressure regulator valve, into intermediate pressure. The pressure reduction is achieved by line pressure initially passing through the diagonal passage in the valve so that it reacts against the left hand end of the valve. Consequently the valve shifts over and partially reduces the line pressure port opening. The reduced output pressure now known as intermedi-

ate pressure valve.

then passes to the throttle pressure

Fig. 5.17 Converter pressure valve (CPV)

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

Get My Free Ebook


Post a comment