Vehicle Differential Brake Clutch Response Time Reduction

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Solution Overview

Problem

The existing hydraulically controlled limited slip clutch in vehicle drivelines experiences long response times due to idling conditions, leading to delayed engagement and potential loss of torque transfer during critical driving situations.

Innovation Solution

Applying a low preparatory hydraulic pressure to the clutch when predetermined driving situations occur, such as brake release, sharp curve negotiation, or high-speed steering, to bring the clutch discs into contact without affecting vehicle dynamics, thereby reducing response time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the clutch is operated only at certain driving conditions, then the vehicle operates normally under normal driving conditions, but the response time becomes long when controlling torque is needed

Engineering Contradiction:
Improveclutch operation reliabilityVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies a low preparatory hydraulic pressure to the clutch in advance during normal driving conditions, bringing the clutch discs into contact without full engagement. This preliminary action ensures the clutch is pre-positioned and ready, reducing the response time when full torque control is needed while maintaining reliable operation during normal conditions

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If a low preparatory hydraulic pressure is applied to the clutch, then the response time is reduced, but the hydraulic system complexity increases

Engineering Contradiction:
Improveresponse timeVSAvoidhydraulic control system complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent applies only a low preparatory hydraulic pressure rather than full engagement pressure during normal conditions. This partial action is sufficient to bring the clutch discs into contact and reduce response time, while avoiding the complexity and energy consumption of full engagement mechanisms

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The hydraulic control system dynamically adjusts the pressure level based on driving conditions - applying low preparatory pressure during normal operation and transitioning to full engagement pressure when torque control is needed. This dynamic approach optimizes both response time and system simplicity

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly reduces the engagement time of the clutch from over 250 ms to a few seconds, enhancing the system's responsiveness and maintaining vehicle stability during quick torque control demands.

Implementation Method 1

a low preparatory hydraulic pressure is applied to the clutch at the occurrence of any one of certain predetermined driving situations

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

a hydraulically controlled limited slip clutch

Methodology Applied
Scientific EffectHydraulic control: Hydraulic Press

Data Source

PatentEP2748026B1Method and device at a vehicle differential brake
Publication Date: 2016.12.14 BORGWARNER SWEDEN AB
  • EP2748026B1 patent drawingFigure 1~2
  • EP2748026B1 patent drawingFigure 3

AI summary

In a driveline in a front wheel drive vehicle the distribution of drive torque to the drive wheels (1) via a differential (6) is controlled by means of a differential brake with a hydraulically controlled limited slip clutch (7). A low preparatory hydraulic pressure is applied to the clutch at the occurrence of any one of certain predetermined driving situations for decreasing the response time for the clutch.