Segmented Thermostat Valve Reduces Opening Force

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Solution Overview

Problem

Conventional thermostat valves for cooling systems of combustion engines face challenges in achieving large flow rates without adverse effects on valve behavior, leading to shifted opening points, dynamic forces during closure, and regulating oscillations due to high opening forces and pressure imbalances.

Innovation Solution

The thermostat valve is designed with two separate components: an annular component and a tappet component, where the tappet is acted upon by the expansive-material element, creating a small initial passage and allowing the annular component to be lifted off the valve seat, reducing opening forces and eliminating dynamic closure forces by relying solely on spring force for opening, thus minimizing regulating oscillations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the diameter of the valve disc is increased to enable large flow rates, then the flow resistance is reduced, but the opening force required increases significantly, shifting the opening point upwards by 5-8 degrees

Engineering Contradiction:
Improveflow rateVSAvoidopening force
Core Design Contradiction:
Quantity of substanceVSForce

Solution Approach 1:

The valve member is divided into two separate components: an annular component with outer and inner sealing portions, and a tappet component that extends through the annular component. This segmentation allows the valve to achieve large flow rates through the annular geometry while the tappet component has a smaller effective area, reducing the opening force requirement.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If the valve member is subjected to high opening forces, then large flow rates can be achieved, but dynamic forces occur during closure that press the thermostat to close temporarily, causing regulating oscillations

Engineering Contradiction:
Improveflow rateVSAvoidvalve behavior stability
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

By segmenting the valve member into annular and tappet components, the patent separates the flow control function (annular component with large diameter) from the actuation function (tappet component with small effective area). This eliminates the dynamic closure forces that cause oscillations while maintaining large flow capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tappet component acts as an intermediary between the expansive-material element and the annular component. It translates the thermal expansion force into valve opening motion while its small effective area prevents excessive dynamic forces during closure, thereby stabilizing valve behavior.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If a single valve member design is used, then the structure is simple, but the valve cannot simultaneously achieve large flow rates and maintain stable opening/closing behavior

Engineering Contradiction:
Improvevalve structureVSAvoidflow rate
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

The patent applies segmentation by creating two distinct components (annular component and tappet component) that work together. The annular component provides large flow area while the tappet component provides controlled actuation, achieving both large flow rates and stable behavior without excessive complexity.

Inventive Principle:
Principle #1Segmentation

4Quantity of substance

If the valve member has large diameter for large flow rates, then coolant delivery is improved, but the expansive-material element must overcome both spring pressure and flow pressure, shifting the opening point

Engineering Contradiction:
Improvecoolant flowVSAvoidopening temperature
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The segmented valve member design separates the flow path (through the annular component with large diameter) from the actuation path (through the tappet component with small effective area). This allows the valve to open at the correct temperature while maintaining large coolant flow capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tappet component serves as an intermediary that isolates the expansive-material element from the large flow pressure forces. By having the tappet (with small effective area) respond to thermal expansion, the opening temperature is accurately controlled while the annular component maintains large flow capacity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration enables smooth opening and reduced dynamic forces during closure, maintaining stable valve behavior and large flow rates without modifying conventional valve casings, ensuring the valve opens independently of system pressure and minimizing oscillations.

Implementation Method 1

an expansive-material element (24) having a tappet component (28) movable in its position in dependence on the temperature of the coolant

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The tappet component (28) has a lower end which sealingly bears against an upper end of the annular component (26)

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

a spring (38) which acts on the annular component (26) and causes the annular component (26) to bear sealingly against a valve seat (20)

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 4

a passage is defined between the sealing portions

Methodology Applied
Scientific EffectFluid flow:

Data Source

PatentEP1715156B1Thermostat valve for a cooling system of a combustion engine
Publication Date: 2013.05.29 ITW AUTOMOTIVE PRODS
  • EP1715156B1 patent drawingFigure 1~2
  • EP1715156B1 patent drawingFigure 3

AI summary

A thermostat valve for a cooling system of a combustion engine, comprising a disc-shaped valve member, having a sealing portion and biased by a spring against an annular valve seat provided in a valve housing, a thermal extension element (DWE) within the valve housing which acts on the valve member opposite to the valve spring, characterized in that the valve member includes two separate parts, the first part being an annular member having an outer annular sealing portion and an inner annular sealing portion, the outer sealing portion cooperating with the valve seat and the second part being a plug-shaped member and extending through the annular member, the plug-shaped member having an outer annular sealing portion which in the closed position of the plug-shaped member cooperates with the inner sealing portion of the annular member, the plug-shaped member cooperating with the thermal extension element (DWE) and being structured such that upon an initial movement of the plug-shaped member by the thermal extension element a passage is formed between the inner sealing portion of the annular member and the outer sealing portion of the plug-shaped member and that upon further movement of the plug-shaped member the annular member is co-moved and lifted from the valve seat.