System and method for decreasing ratio changing time in electronically enhanced powertrain systems
First Claim
1. A method for reducing a ratio changing time in a mechanical powertrain system including an engine having a device operative to retard engine rotation, the engine being coupled to a mechanical change gear transmission having a plurality of gear ratio combinations and a neutral gear state selectively engageable between a transmission input shaft and a transmission output shaft, the system also including an electronic control unit for receiving a plurality of input signals indicative of an engine speed, an output shaft speed, and a neutral gear state, the electronic control unit also being operative to generate command signals for controlling the engine retarding device, the method comprising:
- sensing the neutral gear state which occurs after disengaging a current gear ratio and before effecting engagement of a target gear ratio; and
while the master friction clutch is engaged, applying a retarding torque to the engine while the engine speed is above a synchronous speed at which engagement of the target gear ratio is effected so as to increase engine deceleration and reduce ratio changing time.
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Accused Products
Abstract
A system and method for decreasing the time required to complete a ratio change in an electronically enhanced powertrain system is provided. The powertrain system includes a number of devices for providing a retarding torque to engine rotation to increase the decay rate of the engine speed during an upshift. These devices include an engine brake and an input shaft brake. A retarding torque is also provided by increasing engine accessory load by controlling various engine accessories such as a cooling fan, an air compressor, a hydraulic pump, an air conditioning compressor, and an alternator.
35 Citations
18 Claims
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1. A method for reducing a ratio changing time in a mechanical powertrain system including an engine having a device operative to retard engine rotation, the engine being coupled to a mechanical change gear transmission having a plurality of gear ratio combinations and a neutral gear state selectively engageable between a transmission input shaft and a transmission output shaft, the system also including an electronic control unit for receiving a plurality of input signals indicative of an engine speed, an output shaft speed, and a neutral gear state, the electronic control unit also being operative to generate command signals for controlling the engine retarding device, the method comprising:
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sensing the neutral gear state which occurs after disengaging a current gear ratio and before effecting engagement of a target gear ratio; and while the master friction clutch is engaged, applying a retarding torque to the engine while the engine speed is above a synchronous speed at which engagement of the target gear ratio is effected so as to increase engine deceleration and reduce ratio changing time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 18)
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10. A control system for reducing a ratio changing time of a mechanical powertrain system including an engine coupled to a mechanical change gear transmission having a plurality of gear ratio combinations and a neutral gear state selectively engageable between a transmission input shaft and a transmission output shaft, the powertrain system also including an electronic control unit for receiving a plurality of input signals indicative of an engine speed, an output shaft speed, and a neutral gear state, the electronic control unit also being operative to generate command signals for controlling the engine and the transmission, the control system comprising:
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means for applying a retarding torque in response to a command from the electronic control unit, the retarding torque being applied to the engine while the engine speed is above a synchronous speed at which the target gear ratio is effected so as to increase engine deceleration and reduce ratio changing time; means for monitoring the closure rate at which the engine speed approaches the synchronous speed; and means for controlling application of the retarding torque based on the closure rate. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification