摘要 |
Hydraulic retarder installation with a retarder which is controlled by an electronic control unit (8), which regulates, via an electrically operated proportional valve (9), the air pressure in a hydraulic fluid reservoir (6), said pressure determining the braking torque. In the control unit there are stores command values of the pressure at a number of levels and values of the electric current through the valve at these levels. The control unit is disposed, upon activation of the retarder, by utilizing the stored electric current values and feed back of the measured air pressure on the outlet side of the proportional valve, to control the valve towards a pressure, which corresponds in turn to the requested braking torque. |