|System and damper configuration|
The ECU in the control system determines the level of control current to apply to the linear solenoid incorporated in the damper, using inputs from the vehicle speed sensor. The linear solenoid is attached to the main valve, and alters the pressing force depending on the level of the control current determined by the ECU. The linear solenoid has been chosen because of its operation responsiveness during hard acceleration and deceleration, and for realization of linear damping characteristics in relation to changes to the current.
|Internal construction of HESD|
Check valve: Allows flow of fluid only in one direction into the main valve.
Relief valve: Located in the fluid passage parallel to the main valve, this valve restricts the maximum damping force.
Accumulator: For stabilization of hydraulic pressure in the damper when the fluid volume changes due to temperatures.
|Control of damping force|
The flow resistance changes depending on the angular velocity of the vane and the opening of the main valve. The opening of the main valve depends on the balance of two forces, i.e., the pressing force from the linear solenoid and the counter-acting force from the hydraulic pressure in the main valve.
|Electronic control system|
To realize fine and responsive
damper control, the electronic control system has been employed.
The ECU computes vehicle speed and acceleration by the signals
from the vehicle speed sensor, and determines a linear solenoid
control current using the three dimensional control map. The
damping force is infinitely variable depending on the increase
or decrease of control current.
3 major accomplishments through the development of HESD