Speed control system and method for automotive vehicles

Abstract

In a speed control system for automotive vehicles, a first time difference between values of a timing signal responsive to the actual speed of the vehicle and a command signal indicative of a desired speed is calculated to produce a first differential signal indicative of an absolute value of the first time difference, and a second time difference between respective values of the preceding and following timing signals is calculated to produce a second differential signal indicative of an absolute value of the second time difference and a sign signal indicative of one of positive and negative signs of the second time difference. The absolute value of the second differential signal is adjusted to a smaller value when the sign of the sign signal changes within a duration defined by the preceding and following timing signals, the absolute value of the first differential signal is adjusted in accordance with either one of the absolute and smaller adjusted values of the second differential signal in relation to the sign of the sign signal to produce a correction signal indicative of the adjusted value of the first differential signal, and a control signal is produced in response to the correction signal to control the fuel supply into the prime engine of the vehicle.