Electrohydraulic Thermostat Valve for Wide-Range Fluid Temperature Control

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Solution Overview

Problem

Existing thermostat systems for internal combustion engines, such as those using solenoid valves or wax motors, are inefficient in terms of energy consumption and operational range, failing to effectively manage working fluid temperature across varying engine conditions, which affects engine viscosity and fuel efficiency.

Innovation Solution

An electrohydraulic thermostat system comprising a main valve and a pilot valve, where the pilot valve creates a pressure difference to move the valve body within the main valve, allowing for efficient temperature control of the working fluid by guiding it through a heat exchanger or heater, or bypassing it, thus reducing energy consumption and enhancing operational range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a solenoid valve is used for temperature control, then the system can regulate fluid flow, but energy consumption increases and operational range is limited

Engineering Contradiction:
Improveenergy consumptionVSAvoidoperational range
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent employs hydraulic principles by using pressurized working fluid to actuate the valve body through pressure differential. The pilot valve creates a pressure difference between the fluid distribution chamber and control chamber, causing the valve body to move automatically based on temperature conditions, eliminating the need for continuous electrical power while expanding operational range

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The thermostat system uses the working fluid itself as the actuating medium. The temperature-dependent pressure changes in the working fluid directly move the valve body without requiring external energy input, making the system self-regulating and energy-efficient across varying operational conditions

Inventive Principle:
Principle #25Self-service

2Speed

If a wax motor is used for temperature control, then the system can respond to temperature changes, but response speed is slow and temperature range is limited

Engineering Contradiction:
Improveresponse speedVSAvoidtemperature range
Core Design Contradiction:
SpeedVSTemperature

Solution Approach 1:

The system uses hydraulic pressure transmission through the working fluid to actuate the valve body. This hydraulic mechanism responds instantaneously to pressure changes caused by temperature variations, achieving fast response speed while accommodating a wide temperature range through the fluid's compressibility and flow characteristics

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Use of energy by stationary object

If the valve body is moved by pressurized working fluid, then the pilot valve can be downsized and energy consumption decreases, but system complexity increases

Engineering Contradiction:
Improveenergy consumptionVSAvoidsystem complexity
Core Design Contradiction:
Use of energy by stationary objectVSDevice complexity

Solution Approach 1:

The system is divided into two functional sections: a pilot valve that senses temperature and creates pressure differential, and a main valve body that responds to this differential. This segmentation allows the pilot valve to be small and energy-efficient while the main valve body handles the actual fluid control, balancing complexity with performance benefits

Inventive Principle:
Principle #1Segmentation

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 electrohydraulic thermostat system is more energy-efficient, faster in response, and operates across a wider temperature range, ensuring optimal working fluid viscosity and contributing to fuel savings by effectively managing engine temperature.

Implementation Method 1

the pilot valve is configured to cause a pressure difference between the fluid distribution chamber and the control chamber as a function of the temperature of the working fluid

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

the working fluid moves the valve body in the receiving section due to the pressure difference

Methodology Applied
Scientific EffectPressure-driven motion: Pressure Gradient

Data Source

PatentEP4098850B1Electrohydraulic thermostat system, filter device and method for controlling a temperature of a working fluid
Publication Date: 2025.01.01 MANN HUMMEL GMBH
  • EP4098850B1 patent drawingFigure 1
  • EP4098850B1 patent drawingFigure 2
  • EP4098850B1 patent drawingFigure 3

AI summary

Electrohydraulic thermostat system (8) for a filter device (1), comprising a main valve (10) and a pilot valve (9), wherein the main valve (10) comprises a valve body (23) which is arranged in a receiving section (29) of a housing (22), wherein the valve body (23) subdivides the receiving section (29) into a fluid distribution chamber (30), which is configured to distribute a working fluid (2) to an inflow line (15) of a component (14) for changing a temperature of the working fluid (2) and/or to a bypass line (21) for bypassing the component (14), and a control chamber (31), wherein the pilot valve (9) is configured to cause a pressure difference between the fluid distribution chamber (30) and the control chamber (31) as a function of the temperature of the working fluid (2) so that the working fluid (2) moves the valve body (23) in the receiving section (29) due to the pressure difference for opening and closing the inflow line (15) and/or the bypass line (21).