| 摘要 |
1,156,633. Automatic speed control. AMBAC INDUSTRIES Inc. Oct. 7, 1966 [Nov. 12, 1965], No.44873/66. Heading G3R. The speed of a diesel engine 10 is regulated by fuel controller 12 responsive to signals fed to winding 14 of actuator 16 which is spring-biased in a direction to decrease the fuel supply. A loadbearing gear 22 co-operates with speed-senser 30 producing an original signal having a frequency which varies with the speed of the engine and is variable in amplitude. A saturating amplifier 36 provides a train of pulses recurrent at the frequency of the original signal but of substantially constant amplitude, the widths of the pulses varying inversely with their frequency. The output of the amplifier 36 is applied to filter 80 whose output pulses have amplitudes dependent upon frequency, the response characteristic of the filter having a steep lowerfrequency skirt extending over a limited band wherein the amplitude of the output pulses increases substantially linearly with increase of frequency. A variable inductor 98 permits shifting of the frequency position of the lower-frequency skirt over a range which is large compared with the band occupied by the skirt at any given time. The pulses from the circuit 80 are supplied to a rectifier and D.C. filter 106 to produce a continuous direct voltage which varies in accordance with the amplitude of the input pulses. Thus, the voltage across leads 108, 110, has a value proportional to the pulse frequency when the latter lies within the band occupied by the skirt. The D.C. signal is applied to three-stage transistor amplifier 130 whose output feeds the winding 14. Upon starting, the fuel control is opened by a large current from the D.C. amplifier until the frequency of the original signal reaches the band occupied by the skirt, after which the control signal decreases with increase of speed to stabilize the engine against load variations. The regulated speed is adjusted over a substantial range by adjusting the value of the inductor 98. |
