Electronic speed control system for automotive vehicles
First Claim
1. A speed control system for an automotive vehicle driven by an internal combustion engine under control of a throttle valve, the control system comprising:
- first means for producing a timing signal with a period of time responsive to the actual speed of the vehicle;
second means for producing a command signal indicative of a predetermined period of time defined by a desired speed of the vehicle;
third means responsive to the timing signal for calculating a first time difference between the predetermined period of time and the actual period of time of the timing signal and for producing a first difference signal indicative of an absolute value of the calculated first time difference and a first sign signal indicative of the positive or negative sign of the calculated first time difference;
fourth means responsive to the timing signal for calculating a second time difference between respective actual periods of time of the preceding and following timing signals and for producing a second difference signal indicative of an absolute value of the calculated second time differene and a second sign signal indicative of the positive or negative sign of the calculated second time difference;
fifth means for limiting a value of the second difference signal to a predetermined maximum value when the actual acceleration of the vehicle exceeds a maximum value;
sixth means responsive to the timing signal for calculating a sum of the absolute values when respective signs of the first and second sign signals are identical to each other and for calculating a difference between the absolute values when respective signs of the first and second sign signals are opposite to each other, said sixth means selectively producing first and second correction signals respectively indicative of the calculated sum and the calculated difference and ceasing to produce the first and second correction signals when the respective calculated values are zero;
seventh means responsive to the timing signal and one of the first and second correction signals for selectively producing first and second control signals respectively in relation to the positive and negative signs of the second sign signal; and
actuator means for decreasing and increasing the opening angle of said throttle valve respectively in response to the first and second control signals.
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Abstract
In a speed control system for vehicles, a speed-difference calculation circuit calculates an absolute value of a time difference between a predetermined period of time corresponding with a desired speed and the actual period of time corresponding with the actual speed, an acceleration calculation circuit calculates an absolute value of a time difference between the preceding and following actual periods of time within a limited range, and correction signal generator calculates a sum of the absolute values when each sign of the calculated time differences is positive or negative and calculates a difference between the absolute values when respective signs of the calculated time differences are opposite to each other. The signal generator selectively produces correction signals related to the calculated sum and the calculated difference. A distribution circuit produces a control signal in response to the respective correction signals, and an actuator controls the opening angle of the engine throttle in response to the control signal.
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Citations
5 Claims
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1. A speed control system for an automotive vehicle driven by an internal combustion engine under control of a throttle valve, the control system comprising:
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first means for producing a timing signal with a period of time responsive to the actual speed of the vehicle; second means for producing a command signal indicative of a predetermined period of time defined by a desired speed of the vehicle; third means responsive to the timing signal for calculating a first time difference between the predetermined period of time and the actual period of time of the timing signal and for producing a first difference signal indicative of an absolute value of the calculated first time difference and a first sign signal indicative of the positive or negative sign of the calculated first time difference; fourth means responsive to the timing signal for calculating a second time difference between respective actual periods of time of the preceding and following timing signals and for producing a second difference signal indicative of an absolute value of the calculated second time differene and a second sign signal indicative of the positive or negative sign of the calculated second time difference; fifth means for limiting a value of the second difference signal to a predetermined maximum value when the actual acceleration of the vehicle exceeds a maximum value; sixth means responsive to the timing signal for calculating a sum of the absolute values when respective signs of the first and second sign signals are identical to each other and for calculating a difference between the absolute values when respective signs of the first and second sign signals are opposite to each other, said sixth means selectively producing first and second correction signals respectively indicative of the calculated sum and the calculated difference and ceasing to produce the first and second correction signals when the respective calculated values are zero; seventh means responsive to the timing signal and one of the first and second correction signals for selectively producing first and second control signals respectively in relation to the positive and negative signs of the second sign signal; and actuator means for decreasing and increasing the opening angle of said throttle valve respectively in response to the first and second control signals. - View Dependent Claims (2, 3, 4, 5)
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Specification