Low range drive ratio transfer changeover anti-rollback system and method
First Claim
1. A vehicle anti-rollback method, comprising:
- providing a vehicle that includes a pair of front wheels, a pair of rear wheels, a power unit, and a transmission connecting the power unit to at least one wheel of the front and rear wheels, the transmission including a plurality of forward drive ratios and at least one reverse drive ratio and a two speed gear reduction assembly configured to select between a high range drive ratio and a low range drive ratio when the transmission is in one of the plurality of forward drive ratios;
sensing, using a controller, a vehicle rollback condition when the vehicle transmission is configured in a forward drive ratio; and
the controller configured to execute the following functions;
decreasing torque distributed from the power unit of the vehicle to the at least one wheel, and actuating a brake, when the rollback condition is sensed;
executing drive ratio changeover from the high range drive ratio to the low range drive ratio after the decreasing of the torque and actuating of the brake; and
increasing torque distributed from the power unit of the vehicle to the at least one wheel and releasing the brake after the low range drive ratio has been engaged.
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Accused Products
Abstract
A vehicle anti-rollback system and method can be incorporated into a vehicle that includes a pair of front wheels, a pair of rear wheels, a power unit, and a transmission connecting the power unit to at least one wheel of the front and rear wheels. The transmission can include a plurality of forward drive ratios and at least one reverse drive ratio and a two speed final drive ratio transmission configured to select between a high range drive ratio and a low range drive ratio when the transmission is in one of the plurality of forward drive ratios. A controller can be provided that senses a vehicle rollback condition. When the rollback condition is detected, the controller can decrease torque distributed from the power unit of the vehicle to the at least one wheel, and can actuate a brake. While the vehicle is braked and torque transfer is reduced, the controller can execute drive ratio changeover in a stable manner from the high range drive ratio to the low range drive ratio.
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Citations
20 Claims
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1. A vehicle anti-rollback method, comprising:
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providing a vehicle that includes a pair of front wheels, a pair of rear wheels, a power unit, and a transmission connecting the power unit to at least one wheel of the front and rear wheels, the transmission including a plurality of forward drive ratios and at least one reverse drive ratio and a two speed gear reduction assembly configured to select between a high range drive ratio and a low range drive ratio when the transmission is in one of the plurality of forward drive ratios; sensing, using a controller, a vehicle rollback condition when the vehicle transmission is configured in a forward drive ratio; and the controller configured to execute the following functions; decreasing torque distributed from the power unit of the vehicle to the at least one wheel, and actuating a brake, when the rollback condition is sensed; executing drive ratio changeover from the high range drive ratio to the low range drive ratio after the decreasing of the torque and actuating of the brake; and increasing torque distributed from the power unit of the vehicle to the at least one wheel and releasing the brake after the low range drive ratio has been engaged. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A vehicle anti-rollback system comprising:
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a two-speed gear reduction assembly in series with a multi-ratio transmission assembly of the vehicle and at least one vehicle wheel, the two-speed gear reduction assembly including a low range drive ratio and a high range drive ratio, and the multi-ratio transmission assembly including a reverse drive ratio and a plurality of forward drive ratios; an actuator selectively movable between a low range position where the actuator couples the low range drive ratio in series with a selected one of the plurality of forward drive ratios and a high range position where the actuator couples the high range drive ratio in series with the selected one of the plurality of forward drive ratios; a vehicle power unit connected to the multi-ratio transmission; a vehicle speed sensor; a vehicle acceleration sensor; and a controller in electrical communication with each of the actuator, the vehicle speed sensor and the vehicle acceleration sensor and configured to execute the following functions; sense a vehicle rollback condition according to a set of predetermined parameters including data from the vehicle speed sensor and the vehicle acceleration sensor; and cause a reduction in torque transfer from the power unit to the at least one vehicle wheel and actuate a vehicle brake system when the vehicle rollback condition is sensed. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A vehicle anti-rollback system comprising:
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a two-speed gear reduction assembly in series with a multi-ratio transmission assembly of the vehicle and at least one vehicle wheel, the two-speed gear reduction assembly including a low range drive ratio and a high range drive ratio, and the multi-ratio transmission assembly including a reverse drive ratio and a plurality of forward drive ratios; an actuator selectively movable between a low range position where the actuator couples the low range drive ratio in series with a selected one of the plurality of forward drive ratios and a high range position where the actuator couples the high range drive ratio in series with the selected one of the plurality of forward drive ratios; a vehicle power unit connected to the multi-ratio transmission assembly; at least one vehicle parameter sensor; and a controller in electrical communication with the vehicle parameter sensor and configured to execute the following functions; sense a vehicle rollback condition, according to data received from the parameter sensor, in which the controller determines that the vehicle is likely to roll backwards while the multi-ratio transmission assembly is engaged in one of the plurality of forward drive ratios; cause a reduction in torque transfer from the power unit to the at least one vehicle wheel and actuate a vehicle brake system when the vehicle rollback condition is sensed; and cause the actuator to move to the low range position when the vehicle rollback condition is sensed and the controller has reduced torque transfer from the power unit to the at least one vehicle wheel and has actuated the vehicle brake system. - View Dependent Claims (19, 20)
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Specification