| 摘要 |
1486530 Automatic control of speed DANA CORP 17 July 1975 [24 July 1974] 30005/75 Heading G3R In an automatic speed control system for a vehicle, a dead band is provided in the control to minimize atmospheric bleed to the vehicle manifold and in this dead band a speed control vacuum bellows does not communicate with a vacuum source or atmosphere. As shown, the dead band forms maximum and minimum speed reference signals V 2 , V 1 that are compared with the actual vehicle speed to control valves 110, 114. If the actual value is greater than the maximum V2, bellows 100 Fig. 1 (not shown), linked to the vehicle throttle, are connected by valve 110 to engine manifold vacuum, and if less than the minimum value V 1 are connected by valve 114 to atmosphere. If however the actual value is within the dead band, both valves remian deenergized. The actual vehicle speed signal is determined using a vehicle engine driven switch S 1 to form pulses at a frequency proportional to vehicle speed, which are integrated by R 14 C 6 to produce a speed dependent voltage. This voltage may be modified according to the measured position of the vehicle throttle, to reduce overshoot of the control; In alternatives, the dead band can be provided in the comparator or applied to the actual vehicle speed signal Fig. 3 (not shown). The system may be disengaged manually, when the brakes are applied or when the actual speed is substantially lower than the reference value. |
