IMPROVEMENTS IN OR RELATING TO VEHICLE SPEED CONTROL SYSTEMS

摘要

PCT No. PCT/GB79/00064 Sec. 371 Date Jan. 31, 1980 Sec. 102(e) Date Jan. 30, 1980 PCT Filed Apr. 27, 1979 PCT Pub. No. WO79/01151 PCT Pub. Date Dec. 27, 1979.A vehicle speed control system is disclosed in which a signal Vs representing actual vehicle speed is, when the vehicle is running at a desired speed, momentarily fed into, and then stored in, a memory. The memory therefore produces a signal representing desired speed. An error amplifier compares the signal Vm with a signal Vf which represents actual vehicle speed and which is derived from Vs via a filter. Any speed error causes a drive circuit to adjust the throttle of the vehicle engine so as to tend to correct the vehicle speed error. The vehicle-speed-dependent signal Vf is derived from the actual speed of the engine of the vehicle, and this signal is also fed to a comparator which compares it with a reference signal Vr representing an upper or lower limit for engine speed. When the comparison indicates that the engine speed has exceeded the level represented by the reference Vr (e.g. when the vehicle transmission is inadvertently disconnected), or has fallen below it in an alternative case, a control unit switches off the vehicle speed control system.