Vehicle speed control circuit

In a vehicle having a source of a pulsed vehicle road speed signal of a frequency proportional to the vehicle road speed and a throttle control means, a speed control circuit for automatically maintaining the speed of the vehicle at a desired road speed, comprising:

• a set point means actuated by the vehicle operator when the vehicle reaches the desired road speed and responsive to the first vehicle road speed signal pulse to occur after said actuation for generating a set signal;
• means responsive to said set signal for generating a first signal having a magnitude which is a function of the time elapsed from the occurrence of said first pulse;
• means responsive to said first pulse for generating a second signal having a magnitude which is a different function of the time elapsed from the occurrence of said first pulse;
• means for comparing the magnitudes of said first and second signals and for generating a reset signal when the magnitudes coincide wherein said means for generating said first signal is responsive to said reset signal to terminate the generation of said first signal and includes means to store said first signal as the desired road speed signal;
• and
• comparator and control signal generating means responsive to the vehicle road speed signal and said desired road speed signal for generating a duty cycle modulated control signal to the throttle control means to maintain the speed of the vehicle at the desired road speed.

In a vehicle having a source of a vehicle road speed signal and a throttle control means, a speed control circuit for automatically maintaining the speed of the vehicle at a desired road speed, comprising:

• means actuated by the vehicle operator when the vehicle reaches the desired road speed for generating a desired road speed signal;
• comparator and control signal generating means responsive to the vehicle road speed signal and said desired road speed signal for generating a duty cycle modulated control signal to the throttle control means to maintain the speed of the vehicle at the desired road speed;
• and
• anticipatory control means responsive to said actuation of said means for generating a desired road speed signal for removing the vehicle road speed signal from an input of said comparator and control signal means to drive said control signal to a 100 percent duty cycle to pre-position the throttle of the vehicle.