Internal Combustion Engine Coolant Exchange Control

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Solution Overview

Problem

Existing systems fail to effectively prevent corrosion of the cooling circulation mechanism in internal combustion engines due to oxidative degradation of ethylene glycol-based coolants, leading to excessive corrosion before coolant exchange, as the threshold for exchange is set based on conductivity rather than corrosion risk.

Innovation Solution

A system that includes a temperature sensor, a control device with a measuring unit to track the time coolant exceeds a defined temperature, and a determination unit to prompt coolant exchange based on the type of metal in the flow channel, setting a specific upper-limit accumulated time to prevent corrosion, with shorter times for more corrosive metals like cast iron.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If coolant exchange timing is determined based on accumulated high-temperature time with a fixed threshold, then the system can maintain coolant effectiveness, but the flow channel may already be excessively corroded because the threshold does not account for metal type-specific corrosion resistance

Engineering Contradiction:
Improvecoolant effectivenessVSAvoidflow channel corrosion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by setting different upper-limit accumulated time thresholds based on the specific type of metal in the flow channel. Each metal type (cast iron, aluminum, steel, copper, brass) has its own corrosion-resistant threshold, allowing the system to tailor the coolant exchange timing to the local corrosion resistance characteristics of each metal component, thereby preventing excessive corrosion while maintaining coolant effectiveness.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of the threshold value for accumulated high-temperature time based on the metal type. Instead of using a fixed threshold, the system adjusts the upper-limit accumulated time parameter according to the corrosion resistance characteristics of different metals, enabling optimized coolant exchange timing that prevents corrosion while maintaining reliability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If coolant exchange is prompted when accumulated high-temperature time reaches a threshold set for conductivity, then coolant degradation is addressed, but excessive corrosion occurs because the threshold does not consider metal type

Engineering Contradiction:
Improvecoolant degradation controlVSAvoidflow channel service life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies local quality by establishing different upper-limit accumulated time thresholds for different metal types in the flow channel. Each metal (cast iron, aluminum, steel, copper, brass) has a specific threshold based on its corrosion resistance, allowing the system to optimize coolant exchange timing for each metal type's service life protection while controlling coolant degradation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the threshold parameter of accumulated high-temperature time based on metal type characteristics. By adjusting this parameter according to the corrosion resistance of each metal, the system achieves both coolant degradation control and extended flow channel service life.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a single threshold is used for all metal types, then the system is simple to operate, but it cannot prevent excessive corrosion of corrosion-sensitive metals like cast iron

Engineering Contradiction:
Improvecoolant exchange controlVSAvoidcorrosion of corrosion-sensitive metals
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by setting specific upper-limit accumulated time thresholds for different metal types, particularly protecting corrosion-sensitive metals like cast iron with shorter thresholds. This differentiated approach prevents excessive corrosion of sensitive metals while maintaining ease of operation through automated control.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements a cost-effective solution by using relatively inexpensive temperature sensors and control units that automatically manage coolant exchange. The system accepts shorter service intervals for corrosion-sensitive metals as a trade-off, using affordable components to achieve reliable corrosion protection.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Object-affected harmful factors

If coolant exchange frequency is increased to prevent corrosion, then flow channel protection is improved, but maintenance cost and operational downtime increase

Engineering Contradiction:
Improveflow channel corrosion protectionVSAvoidmaintenance downtime
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent optimizes the parameter of accumulated high-temperature time thresholds based on metal type to achieve the minimum necessary coolant exchange frequency for corrosion protection. By setting appropriate thresholds for each metal type, the system prevents excessive corrosion while minimizing maintenance downtime and operational disruption.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback control by continuously monitoring coolant temperature and accumulated high-temperature time, comparing it against metal-type-specific thresholds, and automatically determining when coolant exchange is necessary. This feedback mechanism optimizes maintenance timing to prevent corrosion while minimizing unnecessary maintenance operations.

Inventive Principle:
Principle #23Feedback

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 system ensures timely coolant exchange, reducing corrosion of the flow channel by setting appropriate upper-limit accumulated times based on the type of metal, thereby preventing excessive corrosion and extending the coolant exchange frequency for non-cast iron components.

Implementation Method 1

a temperature sensor that measures a temperature of the coolant having passed through the engine

Methodology Applied
Scientific EffectThermal energy detection: Heat Sink

Implementation Method 2

a cooling circulation mechanism that circulates a coolant to the engine while cooling the coolant

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

ethylene glycol may be oxidatively degraded under an environment at a temperature exceeding 80°C

Methodology Applied
Scientific EffectOxidative degradation: Oxidation

Data Source

PatentEP4023867B1System comprising an internal combustion engine
Publication Date: 2024.05.08 TOYOTA JIDOSHA KK
  • EP4023867B1 patent drawingFigure 1~2
  • EP4023867B1 patent drawingFigure 3~4
  • EP4023867B1 patent drawingFigure 5

AI summary

An internal combustion system includes a control device having an accumulated amount of time measuring unit that measures an accumulated amount of time by measuring an amount of time when the temperature of the coolant measured by a temperature sensor is equal to or higher than a defined temperature and accumulating the amount of time measured, an exchange determination unit that determines that the coolant needs to be exchanged when the measured accumulated amount of time reaches or exceeds an upper-limit accumulated amount of time, and an upper-limit amount of time setting unit that sets the upper-limit accumulated amount of time for determination by the determination unit in accordance with the type of metal forming the flow channel where the coolant flows.