Interrelated power delivery controls – including engine control – Transmission control – Engine controlled by transmission
Reexamination Certificate
2000-10-04
2001-09-04
Wright, Dirk (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
Engine controlled by transmission
Reexamination Certificate
active
06283892
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a control for a vehicular powertrain comprising a fuel-controlled engine and a multiple-ratio drivetrain, including a multiple-speed mechanical transmission and a single- or multiple-speed drive axle assembly. In particular, the present invention relates to a powertrain control wherein the in-gear position of the shift actuator and the engine torque is monitored and, if the in-gear position indicates a less than fully engaged jaw clutch condition and if the engine torque is low, the jaw clutch is urged into full engagement.
2. Description of the Prior Art
Vehicular drivetrains including multiple-speed mechanical transmissions, usually compound transmissions, or simple transmissions coupled with multiple-speed axles, having 7, 9, 10, 13, 16, 18 or more forward speed ratios, are well known in the prior art, especially for heavy-duty vehicles, as may be seen by reference to U.S. Pat. Nos. 5,370,013; 5,527,237 and 4,754,665, the disclosures of which are incorporated herein by reference. Both synchronized and non-synchronized jaw clutches are known in the prior art, as may be seen by reference to U.S. Pat. Nos. 5,546,823; 5,588,516 and 5,642,643, the disclosures of which are incorporated herein by reference.
Control systems and methods for calculating engine output torque (also called “flywheel torque”) are known in the prior art, as may be seen by reference to U.S. Pat. No. 5,509,867, the disclosure of which is incorporated herein by reference.
Automated and manual transmission systems wherein engine output torque is controlled and/or limited as a function of engaged gear ratio and/or vehicle speed are known in the prior art, as may be seen by reference to U.S. Pat. Nos. 5,477,827; 5,797,110; 5,457,633; 4,889,014; 5,738,606; 5,679,096 and 5,876,302, the disclosures of which are incorporated herein by reference. As is known, modern vehicular powertrains usually include electronically controlled engines, which may be controlled as to engine speed and/or engine torque. By way of example, according to the SAE J-1939 data link protocol, commands may be issued to the engine for fueling of the engine in accordance with (a) driver's fuel demand, (b) a requested engine speed, (c) a requested engine torque and/or (d) a requested maximum engine torque and/or engine speed.
While the prior art systems are effective to maintain an in-gear condition, the use of detents and/or constant urging in higher force actuators being required may result and/or undue wear on the shifting mechanism. In particular, the prior art includes systems having an in-gear detents for maintaining an in-gear condition. While effective, detents are not totally satisfactory as they require higher shift forces and may slow shifts. The prior art also includes systems which, upon sensing a partial disengagement, will urge jaw clutches towards full engagement. These systems are not totally satisfactory as force was applied to the shifting mechanism during torque lock, conditions which might result in undue wear and/or damage.
SUMMARY OF THE INVENTION
In accordance with the present invention, an improved control system/method for a vehicular powertrain is provided, which will tend to maximize in-gear retention while not requiring detents or relatively large capacity actuators and not causing undue wear and/or damage to the shifting elements.
The foregoing is accomplished by sensing a position indicative of the degree of jaw clutch engagement and also sensing engine output torque. If the engaged jaw clutch is not substantially fully engaged, the jaw clutch will be urged towards full engagement only when engine output torque is relatively low (such as less than 10%) of full torque.
Accordingly, it is an object of the present invention to provide a new and improved shift control for a vehicular drivetrain system, including a mechanical transmission wherein engine output torque is a control parameter in determining if an engaged jaw clutch should be urged towards the fully engaged position thereof.
This and other objects and advantages of the present invention will become apparent from a reading of the description of the preferred embodiment taken in connection with the attached drawings.
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patent: 5738606 (1998-04-01), Bellinger
patent: 5797110 (1998-08-01), Braun et al.
patent: 5853306 (1998-12-01), Worth et al.
patent: 6080082 (2000-06-01), Steeby
patent: 6105449 (2000-08-01), Genise et al.
Eaton Corporation
Gordon Howard D.
Wright Dirk
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