Torque Regulation for Drive Train Shifting Comfort

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Solution Overview

Problem

Existing drive-train operation methods using rotational speed regulation for working machines negatively impact driving behavior, particularly during gear shifting and hydrodynamic torque converter clutch engagement, leading to uncomfortable acceleration.

Innovation Solution

A method where a control unit dynamically switches between rotational speed regulation and torque regulation for the drive motor based on driving situations, using signals from the transmission's electronic system to optimize the operation of the hydrodynamic torque converter's bridging clutch, ensuring comfortable shifting and uniform pump operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If rotational speed regulation is used for the drive motor, then uniform pump operation is achieved, but driving behavior deteriorates during gear shifting and clutch engagement

Engineering Contradiction:
Improveuniform pump operationVSAvoiddriving behavior
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The control system dynamically switches between rotational speed regulation and torque regulation modes based on the operating state. When gear shifting or clutch engagement is detected, the system transitions to torque regulation to improve driving behavior, then switches back to rotational speed regulation to restore uniform pump operation. This dynamic adaptation resolves the contradiction by allowing both modes to operate in their optimal contexts.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If rotational speed regulation is maintained during clutch closing, then pump operation remains uniform, but acceleration becomes uncomfortable

Engineering Contradiction:
Improvepump operation uniformityVSAvoiduncomfortable acceleration
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The control system detects the closing state of the bridging clutch in advance and proactively switches from rotational speed regulation to torque regulation before the clutch fully engages. This preliminary action prevents the uncomfortable acceleration from occurring in the first place, while the uniform pump operation is restored after the shifting event completes.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If torque regulation is used during part-load range, then driving comfort improves, but pump operation uniformity deteriorates

Engineering Contradiction:
Improvedriving comfortVSAvoidpump operation uniformity
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The control system applies different regulation strategies to different operational contexts. Torque regulation is applied locally during gear shifting and clutch engagement events to improve driving comfort, while rotational speed regulation is applied during normal pump operation to maintain uniformity. This localized application of different control qualities resolves the contradiction by ensuring each mode operates only where it provides benefit.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS10077053B2Method for operating a drive train
Publication Date: 2018.09.18 ZF FRIEDRICHSHAFEN AG

AI summary

A rotational speed-regulated internal combustion engine in a working machine, for example a wheel loader, shortly before the engaging a bridging clutch of a hydrodynamic torque converter, is switched over in such manner that the internal combustion engine operates under torque regulation when the bridging clutch of the hydrodynamic torque converter is engaged.