Variable Displacement Pump for Dual Clutch Hydraulic Actuation

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Solution Overview

Problem

Automated manual transmissions in commercial vehicles experience interruptions in traction during shifting, leading to reduced driving speed and increased energy consumption, especially when driving uphill, due to inefficient torque delivery from engines which are only effective in a narrow speed range.

Innovation Solution

A hydraulic system utilizing a variable displacement pump driven by an internal combustion engine, which adjusts hydraulic fluid delivery volume based on engine speed and demand, eliminating the need for additional electric motors and reducing energy losses by minimizing excessive fluid delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a constant displacement pump is used to supply hydraulic fluid, then the pump structure is simple, but the energy efficiency deteriorates due to excessive fluid delivery at high engine speeds

Engineering Contradiction:
Improveenergy efficiencyVSAvoidpump structure
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by using a variable displacement pump instead of a constant displacement pump. The pump's delivery volume is made dynamically adjustable through a control device that modifies the pump's operating parameters based on real-time conditions. This allows the system to optimize energy efficiency by delivering only the required hydraulic fluid volume at each engine speed, preventing energy waste from excessive fluid delivery while maintaining a relatively simple pump structure through controlled parameter variation.

Inventive Principle:
Principle #15Dynamics

2Reliability

If hydraulic fluid is continuously supplied to clutches, then traction interruption is minimized, but energy consumption increases due to unnecessary fluid delivery

Engineering Contradiction:
Improvetraction continuityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the hydraulic pump's delivery volume based on actual system needs. The control device monitors engine speed and operational requirements, then modifies the pump's delivery parameters accordingly. This ensures that hydraulic fluid is supplied at the minimum necessary rate to maintain clutch operation and traction continuity, eliminating energy waste from excessive fluid delivery while preserving reliable traction throughout the operating range.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the pump delivers high flow rate at all engine speeds, then clutch actuation is ensured, but energy efficiency deteriorates at low demand conditions

Engineering Contradiction:
Improveclutch actuationVSAvoidenergy efficiency
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent applies partial action by delivering hydraulic fluid at varying rates matched to actual demand rather than continuously at maximum capacity. The control device determines the minimum necessary flow rate required for proper clutch actuation at each engine speed and delivers only that amount. This prevents the energy waste associated with delivering excessive fluid at low demand conditions while ensuring sufficient flow rate is always provided to maintain reliable clutch operation.

Inventive Principle:
Principle #16Partial or excessive action

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

The system ensures continuous tractive force without interruptions, enhancing energy efficiency and reducing fuel consumption by optimizing hydraulic fluid delivery to match the vehicle's operational needs, particularly suitable for commercial vehicles.

Implementation Method 1

a pump (10) for supplying hydraulic fluid to the at least one coupling (2.1, 2.2)

Methodology Applied
Scientific EffectHydraulic fluid delivery: Pump

Data Source

PatentEP3080473B1Hydraulic arrangement for a dual clutch and method for actuating or cooling the dual clutch
Publication Date: 2019.08.21 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP3080473B1 patent drawingFigure 1
  • EP3080473B1 patent drawingFigure 2a~2b
  • EP3080473B1 patent drawingFigure 3

AI summary

The invention relates to a hydraulic arrangement for actuating or cooling at least one clutch of a dual clutch of a vehicle, having a pump for providing a hydraulic fluid for actuating or cooling the at least one clutch; and having an internal combustion engine, which is designed to drive the pump; and having a clutch pressure branch for providing the hydraulic fluid for actuation; and having a cooling branch for providing the hydraulic fluid for cooling; wherein the pump is configured as a variable displacement pump having a variable displacement volume. The invention further relates to a method for actuating or cooling at least one clutch of a dual clutch by means of the hydraulic arrangement.