GB1208492A - Automatic speed control apparatus for automotive vehicles - Google Patents

Abstract

1,208,492. Automatic speed control. MATSUSHITA ELECTRIC INDUSTRIAL CO. Ltd. Jan. 2, 1968 [Jan. 13, 1967(2); Jan.16, 1967; Feb. 21, 1967; Aug.15, 1967; Nov. 16, 1967(2);] No.337/68. Heading G3R. In an automatic control system for a vehicle, a servomotor 121 is coupled to a throttle valve 125 for regulating the speed of the vehicle, a resistor 112 being varied in response to movement of the valve. A generator 100 provides an A.C. voltage representing the vehicle speed, this voltage being rectified, smoothed, and then divided by a resistor 110 for application to a transistor 114. A reference voltage is obtained from resistor 111 and is applied to transistor 115. When the vehicle tends to over-speed, the collector voltage of transistor 115 is increased so that transistors 116, 118 are urged to their on-state. The servomotor 121 drives the throttle valve in its closing direction whereby the voltage across resistor 112 is increased, and the increment of this voltage is applied as a third signal through capacitor 124 to the transistor 115. This third signal increases in correspondence with the acceleration of the vehicle so that the closing stroke of the throttle valve is also increased. When the vehicle tends to under-speed, transistors 117, 119, become conductive and the servomotor opens the throttle valve. The resistor 112 is decreased to reduce the voltage applied to the base of the transistor 115. The resistor 112 may be replaced by a lightshielding plate which is provided with a suitable slit and is coupled to the shaft of the throttle valve. As the plate rotates, the amount of light reading a cadmium sulphide cell is varied together with its resistance. In a modification, a signal representing the acceleration of the vehicle is supplied to the comparator 114, 115, to form the third signal. Alternatively, signals representing the opening of the throttle valve and the acceleration of the vehicle are combined to form the third signal. The acceleration detection may be effected by differentiating a direct voltage which is proportional to the vehicle speed. For this purpose, the voltage across resistor 110 is applied through a capacitor to the base of transistor 114 where it is superimposed upon the speed-responsive signal. The engine may be coupled to a torque converter, the output side of which is coupled to a speed-indicating generator. The input side of the converter is coupled to a further generator which detects the engine speed and is connected through a capacitor to the comparator. The servomotor may be adapted for continuous speed variation by receiving from the comparator a signal representing the difference between the reference and speed-responsive signals, as modified by the third signal. This operation may be additional to the on-off control referred to above. In a further arrangement, the speed of the servomotor is controlled in accordance with the acceleration of the vehicle.