Centrifugal clutch assembly with dedicated maneuvering mode

• US 20060183595A1
• Filed: 02/11/2005
• Published: 08/17/2006
• Est. Priority Date: 02/11/2005
• Status: Active Grant

• Current Assignee: Meritor Transmission Corporation (Meritor, Inc. (Nevada))
• Original Assignee: Meritor Transmission Corporation (Meritor, Inc. (Nevada))
• Inventors: Dreier, Loren C., Heinzelmann, Karl-Fritz, AbuSamra, Muneer, Ronge, Ludger, Sayman, Robert A., DeVore, James H., Allen, Charles E. Jr., Muetzel, Ronald P., Sturmer, Winfried
• Granted Patent: US 7,338,409 B2
• Time in Patent Office: Days
• US Class Current: 477/77
• CPC Class Codes: B60K 31/04 and means for comparing one electrical quantity, e.g. voltage, pulse, waveform, flux, or the like, with another quantity of a like kind, which comparison means is involved in the development of an electrical signal which is fed into the controlling means
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2710/025 Clutch slip, i.e. difference between input and output speeds
• CPC Class Codes: B60W 2710/0616 Position of fuel or air injector

Abstract

A vehicle power train system includes an engine, a transmission, and a centrifugal clutch assembly that selectively couples an engine output shaft to a transmission input shaft in response to an operator input. An operator selects a desired vehicle-operating mode by actuating a shift lever or shift switch from a gear selection device. The gear selection device indicates many different operating modes and includes a low-speed maneuvering mode that is selected for low-speed operations such as coupling a truck to a trailer, or positioning a truck and/or trailer in relation to a loading dock area. Once the low-speed maneuvering mode is selected, a control unit controls at least one of engine speed and engine torque to indirectly effect clutch slippage, which results in improved vehicle speed control at low-speed operations.

Claims

1. A method for controlling vehicle speed comprising the steps of:

(a) manually selecting a maneuvering mode to initiate a low-speed vehicle operation;

(b) controlling at least one of engine output shaft speed or engine output torque to effect clutch slippage; and

(c) controlling vehicle speed by indirectly controlling clutch slippage via step (b).

2. The method of claim 1 further including the steps of monitoring engine speed and engine torque and transmitting speed and torque signals to an engine controller.

3. The method of claim 2 further including the step of solely controlling clutch actuation via centrifugal forces generated in response to rotational output from an engine output shaft.

4. The method of claim 3 wherein step (b) further includes controlling engine fueling to adjust at least one of engine output shaft speed and engine output torque.

5. The method of claim 3 including the step of generating an accelerator pedal position signal and controlling engine output shaft speed or engine output torque during step (b) based on the accelerator pedal position signal.

6. The method of claim 5 including the step of controlling engine fueling in a speed range of rising clutch torque during step (b) over a greater range of accelerator pedal movement in the maneuvering mode than in a normal vehicle operating mode.

7. A power train control system for controlling vehicle speeds comprising:

an engine speed sensor generating an engine output speed signal representing an engine output shaft speed;

an engine torque sensor generating an engine output torque signal;

an engine control unit generating an engine control signal to control engine output shaft speed and engine output torque based on input from an accelerator pedal position sensor signal;

a manual transmission having an input shaft selectively couplable to an engine output shaft and including a plurality of gear ratios;

a gear selection device indicating a plurality of operating modes including at least a low-speed maneuvering mode wherein said gear selection device communicates a selected operating mode to said manual transmission, to said engine control unit, and to a system electronic control unit;

a centrifugal clutch assembly including a first component mounted for rotation with said output shaft, a second component mounted for rotation with said input shaft, and a coupling component responsive to centrifugal forces for selectively coupling said first and second components together such that engine output torque is transferred from said engine output shaft to said input shaft; and

an electronic control unit that automatically modifies said engine control signal in response to selection of said low-speed maneuvering mode wherein said electronic control unit indirectly controls clutch slippage by adjusting at least one of said engine output shaft speed and engine output torque characteristic versus accelerator pedal travel.

8. The system of claim 7 wherein said electronic control unit generates a fuel control command to control at least one of engine output torque and engine output speed.

9. The system of claim 8 including an accelerator pedal position sensor generating the accelerator pedal position sensor signal received by said electronic control unit and wherein said electronic control unit automatically controls engine fueling over a greater range of accelerator pedal travel input movement in said low-speed maneuvering mode than in a normal vehicle operating mode.