| 摘要 |
<p>A vehicle speed control system comprises a memory which stores a signal Vr representing desired road speed which is compared in a comparator with a signal Vs representing actual speed. An actuator responds to any error by adjusting the engine to bring the vehicle to the correct speed. Units are provided to enable the driver to increment or decrement the stored desired speed by small amounts (e.g. 0.5 miles per hour). By means of switches, he can switch into the memory either one of two preset desired speed values. He can also modify these present values, by feeding in, instead, the actual road speed of the vehicle, such modified preset values remaining until the engine is next switched off. The system incorporates a "SOFT OFF" feature, by which, under certain switch off modes of the system, the engine power is not shut off abruptly but at a controlled rate. The system is advantageously implemented by means of a microprocessor. The stored parameters can be arranged to be overwritten by alternative parameters stored in an EPROM.</p> |
