Clutch Overfill Detection
Publication Date: 2017-Jul-28
The IP.com Prior Art Database
Title: Clutch Overfill Detection
Brief Description of the Drawings:
Figures 1A and 1B are representative line graphs of a vehicle motor speed and a vehicle motor acceleration, respectively, during a favorable downshift event.
Figures 2A and 2B are representative line graphs of a vehicle motor speed and a vehicle motor acceleration, respectively, during an unfavorable downshift event.
Background: A clutch assembly of a vehicle (for example, an off‐road work vehicle) transmission typically has
a hydraulically actuated piston that is used for the engagement/disengagement of a set of clutch disks to initiate a shift event, and an algorithm for controlling the shift event.
Each shift event from one speed ratio to another includes a clutch preparation phase during which the clutch is filled with pressurized fluid to an actual fill pressure. When the actual fill pressure is equal to, or greater than the required fill pressure, the clutch is effectively released or disengaged so that the shift event may be completed.
During the shifting event, the actual fill pressure may be expected to vary from a commanded fill pressure due in part to the time response of the various components of the clutch assembly. An “overfill” event may occur when the clutch is filled to an actual fill pressure that is in excess of the required fill pressure and the required fill pressure is achieved earlier than expected, thus allowing a torque transfer event to occur prematurely. In other words, the clutch is sufficiently filled to a required fill pressure before the expected fill time during the shift event.
Description: As shown in the attached illustrations and described below, a clutch control system that detects
an overfill condition by monitoring a motor speed and acceleration during a shift, is disclosed.
Please note that the vehicle of this disclosure is described as an off‐road electric machine work vehicle and is considered to be exemplary, and this disclosure is not limited to any specific vehicle arrangement and that variations are possible without departing from the scope of the disclosure as described below.
Clutch overfill is detected by monitoring a vehicle’s motor speed (e.g., an electric drive motor speed) and acceleration during a shift. This method could also be used in a standard power shift transmission ...