Vehicle speed control with continuously variable braking torque
First Claim
1. A method for reducing speed of a vehicle to maintain a target vehicle speed, the method comprising:
- determining an actual vehicle speed;
comparing the target vehicle speed to the actual vehicle speed to generate a speed error;
determining a continuously variable braking torque as a function of the speed error when the actual vehicle speed exceeds the target vehicle speed; and
applying the continuously variable braking torque to at least one wheel of the vehicle to reduce the speed error toward zero and control the speed of the vehicle.
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Accused Products
Abstract
A system and method for reducing speed of a vehicle to maintain a target vehicle speed include determining an actual vehicle speed, comparing the target vehicle speed to the actual vehicle speed to generate a speed error, determining a continuously variable braking torque as a function of the speed error when the actual vehicle speed exceeds the target vehicle speed, and applying the continuously variable braking torque to at least one wheel of the vehicle to reduce the speed error toward zero and control the speed of the vehicle. The present invention is applicable to vehicles powered by an internal combustion engine, electric vehicles, fuel cell vehicles, and hybrid vehicles. The continuously variable braking torque may be applied using regenerative braking to improve fuel efficiency. Friction brakes may also be utilized either alone, or in combination with regenerative braking, for vehicles capable of brake-by-wire control strategies.
107 Citations
17 Claims
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1. A method for reducing speed of a vehicle to maintain a target vehicle speed, the method comprising:
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determining an actual vehicle speed; comparing the target vehicle speed to the actual vehicle speed to generate a speed error; determining a continuously variable braking torque as a function of the speed error when the actual vehicle speed exceeds the target vehicle speed; and applying the continuously variable braking torque to at least one wheel of the vehicle to reduce the speed error toward zero and control the speed of the vehicle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A computer readable storage medium having stored data representing instructions executable by a computer to reduce speed of a vehicle to maintain a target vehicle speed, the computer readable storage medium comprising:
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instructions for determining an actual vehicle speed; instructions for comparing the target vehicle speed to the actual vehicle speed to generate a speed error; instructions for determining a continuously variable braking torque as a function of the speed error when the actual vehicle speed exceeds the target vehicle speed; and instructions for applying the continuously variable braking torque to at least one wheel of the vehicle to reduce the speed error toward zero and control the speed of the vehicle. - View Dependent Claims (10, 11, 12)
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13. A system for controlling speed of a vehicle capable of reducing speed of a vehicle to maintain a desired vehicle speed, the system comprising:
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a first controller having control logic for determining an actual vehicle speed, comparing the desired vehicle speed to the actual vehicle speed to generate a speed error, and generate a braking torque request representing a continuously variable braking torque as a function of the speed error when the actual vehicle speed exceeds the desired vehicle speed; a braking device coupled to at least one wheel of the vehicle for applying a braking torque to the at least one wheel in response to a braking signal a second controller in communication with the first controller and the braking device, the second controller receiving the braking torque request and generating a braking signal for the braking device to apply a continuously variable braking torque to at least one wheel of the vehicle to reduce the speed error toward zero. - View Dependent Claims (14, 15, 16, 17)
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Specification