Wheel lift identification for an automotive vehicle
First Claim
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1. A method for determining wheel lift of a wheel of an automotive vehicle comprising the steps of:
- applying a change of torque to the wheel;
measuring a change in a wheel condition since initiating the step of applying a change of torque;
indicating wheel lift if the change in the wheel condition is greater than a predetermined value.
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Abstract
A system for detecting wheel lift of an automotive vehicle has a speed sensor (22) coupled to a wheel (12) of automotive vehicle (10). A torque control system (20) is coupled to wheel (12) to change the torque at the wheel. A controller (18) is coupled to the torque control system and a speed sensor. The controller (18) determines lift by changing the torque of the wheel, measuring the change in torque and indicating lift in response to the change in torque which may be indicated by wheel speed.
186 Citations
21 Claims
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1. A method for determining wheel lift of a wheel of an automotive vehicle comprising the steps of:
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applying a change of torque to the wheel;
measuring a change in a wheel condition since initiating the step of applying a change of torque;
indicating wheel lift if the change in the wheel condition is greater than a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
measuring a wheel condition after the step of removing the change of torque.
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4. A method as recited in claim 3 further comprising the step of determining whether the second wheel condition is above a threshold.
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5. A method as recited in claim 1 wherein the step of applying a change of torque comprises applying a brake to the wheel.
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6. A method as recited in claim 5 further comprising the step of releasing the brake;
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determining a wheel condition after the step of releasing the brake;
when the wheel condition does not increase over a reacceleration threshold, confirming wheel lift;
when wheel speed condition increases over a reacceleration threshold, indicating wheel contact.
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7. A method as recited in claim 1 wherein the step of applying a change of torque comprises applying engine torque.
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8. A method for monitoring a predetermined condition of an automotive vehicle having a plurality of wheels comprising the steps of:
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determining a potential for the predetermined condition of the wheel;
measuring a first wheel speed;
thereafter, changing the torque of a suspected lifting wheel from a first torque to a second torque;
changing the torque from the vehicle from the second torque to the first torque;
measuring a second wheel speed;
determining a wheel speed change as a function of the first wheel speed and the second wheel speed;
when the change in wheel speed is greater than a reacceleration threshold, confirming the predetermined condition. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. A system for detecting lift of a wheel of an automotive vehicle comprising:
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a speed sensor coupled to the wheel producing a wheel speed signal;
a torque control system coupled to the wheel for changing the torque at the wheel;
a controller coupled to the said torque control system and the wheel speed sensor, said controller determining lift by changing the torque of the wheel, measuring a change in the wheel speed and indicating lift in response to a predetermined change in wheel speed.
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18. A method for determining wheel lift of a vehicle comprising the steps of:
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applying a torque to the wheel by applying a brake torque;
increasing the brake torque to build until a maximum brake torque threshold is achieved;
detecting the change in wheel speed since the application of brake torque;
comparing the change in wheel speed to a threshold;
when the change in speed is above the wheel speed change threshold value, indicating wheel lift;
when the brake torque reaches a maximum value before the change in wheel speed reaches the threshold, holding the torque for a predetermined amount of time;
continuing to monitor the change in wheel speed during a hold duration;
determining a second change in wheel speed;
comparing the second wheel speed to the threshold value;
when the second wheel speed exceeds the threshold value during the hold duration, indicating a wheel lift. - View Dependent Claims (19, 20, 21)
releasing the torque;
determining a wheel speed change;
when the wheel speed change is greater than a reacceleration threshold, indicating wheel contact;
when the wheel speed change is less than the threshold, confirming an indication of wheel lift.
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20. A method as recited in claim 18 further comprising the step of calculating a traction level.
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21. A method as recited in claim 18 further comprising the step of when wheel lift is detected, continually monitoring the wheel speed change for a sudden increase to acknowledge wheel contact.
Specification