| 摘要 |
<p>An automatic speed control system particularly for use with coaches has a comparator (12) for comparing the actual road speed of the vehicle with a reference to produce an error signal for controlling the engine power via a control unit (18) so as to hold the vehicle at the desired speed. In addition the error signal is fed to a comparator (52) which, if the error signal indicates too high an excess speed, provides positive retardation of the vehicle via a retardation unit (30) which may be the actual brakes of the vehicle or (preferably) its electric retarder. A comparator (54) may also be arranged to be responsive to excess engine speed and to actuate the retarder via an OR gate (60).</p> |
