Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Transmission control
Reexamination Certificate
2000-11-16
2001-07-31
Camby, Richard M. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Transmission control
C701S056000, C701S053000, C701S095000, C192S220100
Reexamination Certificate
active
06269295
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a machine having an engine and electronically controlled transmission, more particularly to an apparatus, method and product for transmission control, and even more particularly to an apparatus, method and product for transmission control during braking.
BACKGROUND ART
Brake systems of heavy machinery, non-limiting examples of which include wheel loaders and motor graders, generally include mechanism for shifting the transmission into neutral upon braking.
On most commercially available machines, the neutralizer function associated with the brake application is accomplished by providing an electric proximity switch which closes when the brake pedal is depressed a given amount. This electric signal is used by the transmission control to shift the transmission into neutral. When the pedal is released, the proximity switch opens and the transmission control re-engages the transmission. By the time the transmission re-engages, the brakes have been released. See for example, U.S. Pat. No. 3,998,111, issued Dec. 21, 1976 to Blake, and herein incorporated by reference.
One drawback of such a neutralizer control is that it provides poor inching capability in that it does not easily allow the operator to achieve slow, smooth machine movement without running against the torque converter. Consequently, some operators have been known to turn off the neutralizer function, using the standard neutralizer disable switch for all applications. This results in a reduction in service brake life, increased axle oil temperatures, possible reduction in differential and final drive gear and bearing lives, increased fuel consumption and increase in power train heat loads because the operator runs the machine against the torque converter by applying the brakes with transmission in gear.
In an effort to overcome some of the above described disadvantages, a few commercially available machines include operator selectable neutralizer operating modes to accommodate a variety of applications. These selectable modes usually provide two or three discrete brake pedal positions at which the transmission is shifted to neutral and re-engaged. However, these offer only a partial solution, as the correct mode for the application must be selected, and even that mode will not always provide adequate operation for all situations of that application.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, there is provided a neutralizing method for operating machine transmission during braking. The method includes obtaining data relating to brake pedal position, machine velocity, machine engine speed, current transmission operating gear, and lowest operating gear. The method also includes, setting downshifting thresh holds based on whether pedal position is in a downshift mode or a braking mode. The method even also include downshifting the transmission if the machine velocity and machine engine speed are less than the downshifting thresh holds, and if the transmission operating gear is not the lowest operating gear. The method still also includes neutralizing the transmission if the pedal position is in a neutralizing mode, if the velocity is less than a neutralizing thresh hold velocity, and if the transmission is in the lowest operating gear. Finally, the method includes repeating the above steps until the transmission is neutralized.
In another aspect of the present invention, there is provided an inching method of operating the transmission once is has been neutralized. This inching method may be operated with or independently of the neutralizing method described above. This inching method includes a data obtaining step of obtaining data relating to pedal position, including a current position and a maximum depressed depression position (MDDP). Next, if the current position exceeds the MDDP, the method includes resetting MDDP to the current position and repeating the data obtaining step. The method then includes engaging the transmission and allowing machine movement if the pedal position has moved a thresh hold amount away from the maximum depressed depression position. The method then includes repeating the data obtaining step if the brake pedal is not fully released. The method finally includes returning control to the automatic transmission controller.
In another aspect of the present invention, there is provided a computerized system for operating a machine transmission during braking. The system includes hardware and software for carrying out the neutralizing and/or inching methods as described above.
In even another aspect of the present invention, there is provided computer readable media comprising software for operating a machine transmission during braking. The software is suitable for carrying out the neutralizing and/or inching methods as described above.
REFERENCES:
patent: 3667579 (1972-06-01), Vizza
patent: 3998111 (1976-12-01), Blake
patent: 4103764 (1978-08-01), Iijima
patent: 4113076 (1978-09-01), Lee et al.
patent: 4262335 (1981-04-01), Ahlen et al.
patent: 4757449 (1988-07-01), Kazumasa et al.
patent: 4955255 (1990-09-01), Yamasushi et al.
patent: 4965728 (1990-10-01), Leising et al.
patent: 5052531 (1991-10-01), Bota
patent: 5101943 (1992-04-01), Bulgrien
patent: 5105923 (1992-04-01), Iisuka
patent: 5203235 (1993-04-01), Iisuka
patent: 5520593 (1996-05-01), Yesel et al.
patent: 5954776 (1999-09-01), Saito et al.
patent: 6059688 (2000-05-01), Nozaki et al.
patent: 6095944 (2000-08-01), Buchanan et al.
patent: 6173228 (2001-01-01), Carlson et al.
patent: 405196119 (1993-08-01), None
Gaugush Susan J.
Hubbard Milton C.
Palmer Marvin K.
Schoenberg Matthew F.
Wulfert Wayne J.
Buck Byron G.
Camby Richard M.
Caterpillar Inc.
Meyers Liza J.
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