Engine Cooling Device Thermal Deformation Control

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Solution Overview

Problem

Existing cooling devices for internal combustion engines face delays in temperature increase due to thermal deformation in heat exchangers when cooling water with increased temperature is supplied, as they attempt to mitigate thermal shock by preheating both the engine and heat exchanger, leading to inefficient cooling.

Innovation Solution

A cooling device with a switching unit, inlet and outlet temperature detectors, and a controller that adjusts the cooling water flow between a heat-exchanging path and a bypass path based on temperature differences to minimize thermal deformation, using a stored correlation to set the optimal flow volume and prevent heat exchanger damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cooling water having increased temperature is supplied to the heat exchanger to raise the heat exchanger temperature and alleviate thermal deformation, then thermal deformation is reduced, but the temperature increase of the internal combustion engine is delayed

Engineering Contradiction:
Improveheat exchanger thermal deformationVSAvoidtemperature increase speed of internal combustion engine
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The switching unit dynamically adjusts the cooling water flow path based on real-time temperature conditions. It transitions from a static flow path to a dynamic one that can switch between bypassing the heat exchanger and flowing through it, allowing optimal temperature control for both engine warming and heat exchanger protection

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller changes the flow path parameter based on temperature differential detection. When the temperature difference between cooling water and heat exchanger exceeds a threshold, the system switches to bypass mode; otherwise, it allows flow through the heat exchanger, thereby controlling thermal deformation while maintaining engine temperature rise speed

Inventive Principle:
Principle #35Parameter changes

2Reliability

If cooling water is supplied to the heat exchanger during engine startup, then thermal deformation is alleviated, but heat generated is used to raise heat exchanger temperature instead of engine temperature

Engineering Contradiction:
Improveheat exchanger thermal deformationVSAvoidengine temperature rise efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary detection of temperature conditions before directing cooling water flow. The temperature detectors and controller prepare the switching unit to bypass the heat exchanger during critical engine warm-up phases, ensuring engine temperature rise efficiency is prioritized before thermal deformation becomes a concern

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The switching unit extracts the cooling water flow from the heat exchanger path and redirects it through the bypass path when engine temperature rise is prioritized. This separation allows independent control of engine warming and heat exchanger temperature management

Inventive Principle:
Principle #2Taking out (Extraction)

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 allows for rapid temperature increase of the engine while preventing heat exchanger damage from thermal deformation, improving cooling efficiency by optimizing the cooling water flow to prioritize engine heating over heat exchanger preheating.

Implementation Method 1

The cooling water passing through the cooling-water flow path in the heat exchanger exchanges heat with the internal combustion engine, whereby temperatures of the internal combustion engine are controlled

Methodology Applied
Scientific EffectHeat exchange: Convection

Implementation Method 2

If the cooling water having increased temperature suddenly enters the heat exchanger at normal temperatures at the start of the internal combustion engine, a temperature difference takes place before and after the entrance of the cooling water, which causes the heat exchanger to suffer from thermal impact (also referred to as 'thermal shock'). This thermal impact possibly leads to occurrence of thermal deformation in the heat exchanger

Methodology Applied
Scientific EffectThermal shock: Thermal Shock

Implementation Method 3

a temperature difference takes place before and after the entrance of the cooling water, which causes the heat exchanger to suffer from thermal impact

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3018317B1Cooling device for internal combustion engine, and cooling method for internal combustion engine
Publication Date: 2017.09.27 NISSAN MOTOR CO LTD
  • EP3018317B1 patent drawingFigure 1~2
  • EP3018317B1 patent drawingFigure 3
  • EP3018317B1 patent drawingFigure 4

AI summary

Provided are: a three-way valve (12) provided on an outlet side of a cooling-water flow path (L1), and configured to branch the cooling-water flow path (L1) into a heat-exchanging flow path (L3) having a heat exchanger (14) for cooling of cooling water disposed therein, and a bypass flow path (L2); a first temperature detecting unit (21) that detects an inlet temperature of the cooling water supplied to the heat exchanger (14); a second temperature detecting unit (22) that detects an outlet temperature; and a control unit (23) that controls distribution of the volume of flow of the cooling water output from the three-way valve (12). The control unit (23) stores a correlation between a temperature difference ΔT between an inlet temperature and an outlet temperature of the heat exchanger (14), and the amount of thermal deformation occurring in the heat exchanger (14). At the time when the cooling water is supplied to the heat-exchanging flow path (L3), the control unit (23) refers to the temperature difference ΔT and the correlation to obtain the volume of flow of the cooling water supplied to the heat-exchanging flow path (L3) so that the amount of thermal deformation is less than or equal to a threshold amount of thermal deformation set in advance.