| 摘要 |
A vehicle speed control system is disclosed which is primarily intended for heavy vehicles and which is arranged to 'anticipate' an uphill section of road immediately following a downhill section, so as to prevent loss of momentum gained on the downhill section. A comparator compares an actual speed signal Vs with a driver-settable desired speed signal Vr and produces an error signal. A level changing circuit produces an output equal to Vr in normal circumstances, but which follows Vs when the vehicle accelerates downhill. This output is fed through a memory via a switch which is open when an acceleration-deceleration unit detects that the vehicle has reached the foot of the hill. This memory therefore stores a signal Vr' representing the speed at that time, and the comparator therefore increases the engine power when the vehicle speed has fallen below this augmented reference speed, instead of waiting for the speed to fall to the original reference. Another comparator detects when the vehicle speed on the uphill section has fallen to the original desired speed and closes the memory switch so that the reference reverts to Vr. Another unit closes the memory switch to ensure that the reference is brought back from Vr' to Vr if the vehicle speed increases (such as if the downhill section is followed by a level section of an uphill section). |
