Abstract:
A gear ratio shift control and control method controls gear ratio upshifts in a multiple-ratio transmission for an automotive vehicle. Pressure actuated friction elements establish torque flow paths in transmission gearing as they are selectively engaged and released. A net torque reduction at a transmission torque output shaft during an upshift event is reduced by increasing transmission input torque prior to the start of the inertia phase of the upshift event.
Abstract:
A multiple-ratio transmission with planetary gearing and a friction clutch and brake for controlling relative motion of the gearing to establish multiple driving ratios between an internal combustion engine and vehicle traction wheels, the clutch and brake include a forward drive clutch and a reverse drive clutch for establishing torque flow paths through the gearing. The forward drive clutch establishes a torque flow path through the gearing from the engine through a torque output element of the transmission during vehicle startup in forward drive range, and the reverse clutch establishes a corresponding torque flow path during startup in reverse. A mechanical connection between the torque input shaft of the gearing and the crankshaft is characterized by minimal rotating mass, thereby reducing the inertia of rotating mass of the elements of the transmission.
Abstract:
A powertrain assembly for an automotive vehicle having an interanal combustion engine and transmission gearing for delivering engine torque to traction wheels of a vehicle. An electric induction motor is situated in the torque flow path between the engine and the transmission. The induction motor complements engine torque which permits the engine to be turned off when the vehicle is at rest, thereby improving fuel economy and rendering undesirable exhaust gas emissions from the internal combustion engine. The torque multiplication that would normally be available from a hydrokinetic torque converter in the transmission is essentially replaced with auxiliary launch torque supplied by the induction motor during vehicle startup. The vibration damping function of a hydrokinetic torque converter during engine idle is also performed by the induction motor. Therefore, a hydrokinetic torque converter in the transmission in not necessary. The induction motor, during those operating modes of the vehicle when induction motor torque is not required to deliver driving torque, functions as an alternator during periods of regenerative braking with the internal combustion engine inactive and with the vehicle in a coast mode.
Abstract:
A method for controlling torque transfer between first and second friction elements in an automatic transmission having a hydraulic band brake servo in which a magnet is fixed to a displaceable piston, and a sensor producing a signal responsive to the sensed intensity of a field produced by the magnet representing the position of the servo piston, producing from the signal an indication of the position of the servo piston, determining a reference threshold servo position corresponding to incipient band brake torque capacity, and reducing pressure in the second friction element when the current servo displacement equals the threshold displacement.
Abstract:
A controller and control strategies minimize shift shock in a hybrid electric vehicle during a downshift during regenerative braking by maintaining the transmission input speed substantially linear when the transmission input speed is slowing. The controller and the control strategies control the regenerative braking torque during a downshift occurring during regenerative braking in such a way that the transmission input speed is maintained substantially linear when the transmission input speed is slowing during a torque phase of the downshift.
Abstract:
A vehicle includes a motive power source, a transmission, and a clutch system. The vehicle further includes a controller that causes the clutch system to generate a generally constant clutch pressure to mechanically couple the motive power source and transmission as a line pressure associated with the transmission varies.
Abstract:
A hybrid electric vehicle includes an engine and a traction motor coupled to the engine by a coupling device or a clutch for providing torque to wheels of the vehicle. An inverter is electrically connected to the traction motor. A second coupling device or at least one clutch at least indirectly selectively couples the motor to the drive wheels. A controller controls the second coupling device based upon a temperature of at least one of the fraction motor and the inverter.
Abstract:
A method of controlling a hybrid vehicle having a step ratio transmission is disclosed. The method utilizes terrain data to reduce the number of shift events. The method comprises receiving data indicative of a grade profile of an anticipated route, identifying a forecast shift sequence comprising a forecast downshift event and an adjacent forecast upshift event, and adjusting the shift criteria based on the time between the forecast shift events, the road grade between the forecast shift events, and the state of a storage battery.
Abstract:
A system and method for automatically angularly positioning wheels of an automotive vehicle after parking. The system disclosed here includes a power-assisted steering system coupled to the wheels. Further, the system includes a controller, coupled to the steering system, which is configured to automatically position the wheels in a desired direction, based on a determination that the vehicle is parked.
Abstract:
A vehicle includes an engine, a traction motor, and a torque converter that is driven by the traction motor. A clutch arrangement mechanically couples an output of the torque converter to transmission gearing. A controller is provided in the vehicle that is configured to command an increase in slip, or decrease in clutch pressure, in the clutch arrangement in response to an increase in speed of the traction motor. The commanding of an increase in slip enables a product of the torque ratio of the torque converter and an input torque to the torque converter to remain generally constant during the increase in speed of the traction motor.