The hydraulic accumulator damps pressure surges in the system to smooth out jerks when shifting gears, which ensures the required quality of gear shifting.

When a friction control starts (clutch or brake), main line pressure selects the gap between the discs, overcoming the pressure of the return springs. When the gap has been selected the pressure in the booster rises of the included element. There is a blow as a result. In order to prevent this from happening, hydraulic accumulators are installed parallel to the friction control booster. With a full selection of the gap in the discs of the friction element, the hydraulic accumulator piston moves, reducing the rate of pressure increase in the booster of the included element.

The moment the piston starts moving and the speed of its movement depends on the stiffness of the hydraulic accumulator spring. In the hydraulic accumulators of the direct clutch and the second gear brake, in addition to the spring, the back pressure is used.

Accumulator control valve

A special valve controls the operation of the hydraulic accumulator. This valve generates the back pressure from the pressure of the main line proportional to the degree of throttle opening.