Cooling System Thermostat Bypass for Rapid Thermal Response

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Solution Overview

Problem

Conventional cooling systems for internal combustion engines with motor-operated valves and thermo valves are large, difficult to mount, and costly, and they face challenges in rapid air heating and knocking suppression due to the separation of cooling functions.

Innovation Solution

The cooling system integrates a thermostat that opens and closes main passages to the radiator and eliminates the need for a thermo valve on the motor-operated valve, allowing the motor-operated valve to be downsized and enabling rapid air heating and knocking suppression by bypassing the thermostat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a motor-operated valve with a thermo valve is used to provide fail-safe cooling function, then the reliability is improved, but the device complexity and size increase

Engineering Contradiction:
Improvefail-safe cooling functionVSAvoidintegrated unit size
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent separates the fail-safe cooling function from the motor-operated valve by providing a dedicated bypass passage that operates independently of the valve mechanism. This segmentation allows the motor-operated valve to be simpler while maintaining system reliability through the alternative cooling path.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bypass passage acts as an intermediary cooling path that activates when the primary cooling system fails. This mediator provides a fallback mechanism without requiring the motor-operated valve to have built-in fail-safe complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a thermostat with a jiggle valve for air bleeding is used, then the air bleeding function is improved, but the device complexity increases

Engineering Contradiction:
Improveair bleeding functionVSAvoidthermostat structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The air bleeding function is separated from the thermostat by providing a dedicated air bleeding passage that operates independently. This allows the thermostat to focus on temperature control while air bleeding is handled by the separate passage structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The air bleeding passage is designed to automatically bleed air from the cooling system without requiring additional valves or complex mechanisms. The passage structure itself enables the air bleeding function through its geometry and positioning.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If the motor-operated valve controls coolant distribution to multiple devices, then the adaptability is improved, but the response speed for rapid temperature changes decreases

Engineering Contradiction:
Improvecoolant distribution controlVSAvoidresponse speed for temperature changes
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The cooling system is divided into multiple independent passages (bypass passage, air bleeding passage, main cooling passage) that can be controlled independently. This segmentation allows selective activation of specific cooling paths for rapid response to different thermal conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system provides dynamic control by enabling the bypass passage to open rapidly in response to thermal conditions, knocking, or other events without waiting for the motor-operated valve to adjust. This creates a faster, more responsive cooling system.

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 configuration improves on-vehicle mountability, reduces costs, achieves quick air heating by rapidly raising coolant temperature, and suppresses knocking at an early stage by lowering the coolant temperature rapidly.

Implementation Method 1

A thermostat 7 that opens and closes a main passage L1 through which the coolant circulates between the water jacket 2a and the radiator 3

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

a motor-operated valve 8 for changing the distribution of the coolant supplied to each heat exchanger by opening and closing the auxiliary passage L2

Methodology Applied
Scientific EffectValve actuation: Valve

Implementation Method 3

the coolant, which is circulated between a water jacket 2a of the internal combustion engine 2 and a radiator 3, is also circulated through heat exchangers, such as an air-heating heat exchanger 4

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4177448B1Cooling system
Publication Date: 2025.05.28 NIPPON THERMOSTAT CO LTD
  • EP4177448B1 patent drawingFigure 1
  • EP4177448B1 patent drawingFigure 2
  • EP4177448B1 patent drawingFigure 3

AI summary

Provided are a cooling system and a method for controlling the same, with which it is possible to withdraw air in a coolant flow path, quickly raise a coolant temperature to quickly heat air during air-heating, and quickly lower the coolant temperature to minimize knocking early when knocking occurs. A cooling system 1 comprises a main passage L1 (L1a-L1c) through which a coolant is circulated between an internal combustion engine 2 and a radiator 3, an auxiliary passage 12 (L2a - L2c) through which the coolant is circulated between the internal combustion engine and heat exchangers 4, 5, 6, a thermostat 7 that opens and closes the main passage L1 in accordance with the temperature of the coolant, a thermostat bypass path L3 (L3a, L3b) that bypasses the thermostat to allow communication between the internal combustion engine and the radiator, and a motor-operated valve 8 that opens and closes the auxiliary passage and the thermostat bypass path.