Integrated Gearbox Oil Heat Exchanger With Shape Memory Bypass

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Solution Overview

Problem

Existing heat exchange systems for vehicles, particularly in gearbox oil cooling, face challenges with slow thermal actuator response times leading to hysteresis and lubrication performance issues, and require large installation spaces due to bulky thermal actuators and complex piping arrangements.

Innovation Solution

A heat exchange device incorporating a thermostatic assembly with a shape memory alloy spring and return spring, allowing for fast thermal response and compact design, where the shape memory alloy spring activates above a predetermined temperature to redirect fluid flow through a heat exchange passage, and deactivates below it to use a bypass passage, reducing the need for large thermal actuators and simplifying installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional thermal actuators are used to control fluid flow paths, then the heat exchange system can regulate temperature, but the response time is slow causing hysteresis and reduced lubrication performance

Engineering Contradiction:
Improvelubrication performanceVSAvoidthermal actuator response time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the material parameter of the actuator from traditional thermal expansion materials to shape memory alloy, which exhibits superelasticity and rapid thermal response characteristics. This material parameter change enables the actuator to respond quickly to temperature changes, eliminating hysteresis and improving lubrication performance by timely redirecting fluid flow when overheating occurs

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the traditional mechanical thermal actuator system with a shape memory alloy-based actuator that utilizes phase transformation mechanics. This substitution eliminates the slow thermal mass heating/cooling cycle of traditional actuators, providing rapid response to temperature changes and immediate control of the thermostatic valve for optimal lubrication

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If bulky thermal actuators and complex piping arrangements are used, then the heat exchange system can function properly, but large installation spaces are required

Engineering Contradiction:
Improveheat exchange functionVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges the thermostatic valve assembly with the heat exchanger body into an integrated unit. The shape memory alloy actuator is positioned within the heat exchanger structure, and the bypass passage is incorporated directly into the heat exchanger body. This merging eliminates the need for separate bulky actuators and complex external piping, achieving compact installation while maintaining full heat exchange functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a nested structure where the thermostatic valve is embedded within the heat exchanger body. The shape memory alloy actuator is housed inside the valve assembly, and the bypass passage is integrated into the heat exchanger's internal structure. This nesting arrangement minimizes the overall footprint and installation space while preserving all necessary heat exchange and temperature control functions

Inventive Principle:
Principle #7Nested doll (Nesting)

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 solution provides rapid temperature regulation with minimal space requirements, enhancing transmission performance and safety by reducing hysteresis and simplifying installation, while maintaining efficient cooling of gearbox oil.

Implementation Method 1

a shape memory alloy spring (12), and a valve sleeve (11)... The shape memory alloy spring (12) is made of a memory alloy material... In a case that the temperature is greater than or equal to the predetermined temperature, the elastic potential energy of the shape memory alloy spring (12) is activated

Methodology Applied
Scientific EffectShape memory alloy: Shape Memory Alloy

Implementation Method 2

a return spring (13)... under the action of the return spring (13), the valve sleeve (11) is at a first position... under the action of the elastic force difference between the shape memory alloy spring (12) and the return spring (13), the valve sleeve (11) slides to a second position

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 3

a heat exchanger body and a thermostatic assembly... The heat exchanger body includes a heat dissipation assembly (21), a fluid inlet (2a), a fluid outlet (2b), a heat exchange passage (2f)... so as to maintain the temperature of the gearbox oil within a certain working temperature range

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3702590B1Heat exchange device
Publication Date: 2023.04.05 ZHEJIANG SANHUA AUTOMOTIVE COMPONENTS CO LTD
  • EP3702590B1 patent drawingFigure 1
  • EP3702590B1 patent drawingFigure 2
  • EP3702590B1 patent drawingFigure 3

AI summary

A heat exchange device, comprising a heat exchanger main body (2) and a temperature regulation assembly (1); when the temperature of an oil that flows into a valve cavity is higher than or equal to a preset temperature, the elastic potential energy of a memory spring (12) of the temperature regulation assembly (1) is activated, and the oil enters a heat exchange channel (2f) for heat exchange; otherwise, the oil directly flows out of the heat exchanger main body (2) by means of a bypass channel (2e) without passing through a heat dissipation assembly (21); the thermal reaction of the memory spring (12) is fast and response time is short, greatly improving the operating performance and usage safety of a transmission; moreover, the memory spring (12) is small in size, and has higher installation stability, while cooperative use with other parts is not necessary, thus simplifying the structure of the temperature regulation assembly (1), and greatly reducing the size of the temperature regulation assembly (1); the temperature regulation assembly (1) may be installed at the position of a fluid inlet of a plate heat exchanger, the two being integrated into a comprehensive design, and thus on-site installation is not required, increasing installation efficiency, greatly reducing the space occupied in a vehicle, and being beneficial in optimizing overall vehicle design.