Method of overriding ratio matching feature in power shift transmissions
AssigneeFord New Holland, Inc.
InventorGarth H. Bulgrien
Life of this patent
Estimating the term…
Abstract
A power shift transmission having a ratio matching feature whereby the disengagement of the transmission by moving the gearshift lever to the neutral position or by depressing the clutch pedal initiates a routine in the microprocessor controlling the operation of the transmission to calculate the ratio of the rotation of the input and output shafts of the transmission and select the gear most closely matching the calculated ratio is disclosed wherein the ratio matching routine can be manually overridden by signalling a gear change with the gearshift lever. The override feature for the ratio matching routine can be permanent for each disengagement of the transmission or temporary for the running of a timer for a predetermined length of time.
Claims17
A method of controlling the operation of a vehicle transmission operably connected to an engine and having a plurality of clutches for selectively interconnecting an engine driven input drive shaft, an output drive shaft operatively coupled to ground engaging wheels of said vehicle to effect movement thereof over the ground, and a plurality of gears rotatably housed in said transmission in driving relationship with said input and output drive shafts such that a selective engagement of said clutches will effect a varying of the speed of operation of said output shaft for a given speed of operation of said input shaft, said transmission further having an electrical control system including a microprocessor responsive to switches actuated by manual movement of a gearshift means between a plurality of positions, including forward, reverse, and neutral positions, for controlling said clutches in the transmission, said microprocessor being operable to engage a ratio matching routine when said gearshift means is placed in said neutral position to select a gear having a gear ratio substantially equivalent to the ratio derived from the respective speeds of rotation of said input and output shafts, the method comprising:
- signalling said microprocessor for an upshift or a downshift of said transmission while engaged in said ratio matching routine;
- and
- exiting said ratio matching routine and entering a gear selection routine in said microprocessor while said gearshift remains in said neutral position to effect a selection of an alternative gear other than the gear selected by said ratio matching routine.
A method of controlling the operation of a vehicle transmission operably connected to an engine and having a plurality of clutches for selectively interconnecting an engine driven input drive shaft, an output drive shaft operatively coupled to ground engaging wheels of said vehicle to effect movement thereof over the ground, and a plurality of gears rotatably housed in said transmission in driving relationship with said input and output drive shafts such that a selective engagement of said clutches will effect a varying of the speed of operation of said output shaft for a given speed of operation of said input shaft, said transmission further having an electrical control system including a microprocessor responsive to switches actuated by manual movement of a gearshift means between a plurality of positions, including forward, reverse, and neutral positions, for controlling said clutches in the transmission, said gearshift means also being positionable in gear change positions while in said neutral position to signal said microprocessor for effecting a change in the selected gear, said microprocessor being operable to engage a ratio matching routine when said gearshift means is placed in said neutral position to select a gear having a gear ratio substantially equivalent to the ratio derived from the respective speeds of rotation of said input and output shafts, the method comprising:
- moving said gearshift means into a gear change position to activate a corresponding switch when said microprocessor is engaged in said ratio matching routine;
- and
- changing the gear selection according to the switch activated by said moving step;
- activating a timer to run for a first predetermined interval of time;
- exiting said ratio matching routine to shift said transmission to the gear selected in said changing step if said gearshift means is removed from said neutral position before the expiration of said first predetermined interval of time;
- and
- remaining in said ratio matching routine if said first predetermined interval of time expires prior to moving said gearshift means from said neutral position.
A method of selecting a gear in a vehicle transmission operably connected to an engine and having a plurality of clutches for selectively interconnecting an engine driven input drive shaft, an output drive shaft operatively coupled to ground engaging wheels of said vehicle to effect movement thereof over the ground, and a plurality of gears rotatably housed in said transmission in driving relationship with said input and output drive shafts such that a selective engagement of said clutches will effect a varying of the speed of operation of said output shaft for a given speed of operation of said input shaft, said transmission further having an electrical control system including a microprocessor responsive to switches actuated by manual movement of a gearshift lever between a plurality of positions, including forward, reverse, and neutral positions, for controlling said clutches in the transmission, the method comprising:
- disengaging said transmission so that rotational power from said engine is not being transferred from said input shaft to said output shaft;
- displaying the previously utilized gear;
- if a change of the displayed gear is desired, selecting a gear by selectively moving said gearshift lever to activate a corresponding switch to signal said microprocessor of a selection of a desired gear;
- after said selecting step, activating a timer to run for a first predetermined period of time;
- after said selecting step, displaying said desired gear;
- if said selecting step is not desired or if said first interval of time expires while said transmission remains disengaged, calculating a ratio of the rotational speed of said output shaft divided by the rotational speed of said input shaft and designating a chosen gear within said transmission having a gear ratio substantially equivalent to the calculated ratio;
- after said calculating and designating steps, displaying said chosen gear;
- and
- re-engaging said transmission to shift to the displayed gear.
Dependencies are inferred from the claim text.