Engine Cooling System Flow Rate Optimization

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Solution Overview

Problem

The existing cooling systems for internal combustion engines face challenges in maintaining a proper flow rate of cooling water, leading to increased pressure loss and decreased heat transfer efficiency, particularly during high load operations where knocking occurs, and inefficient fuel consumption during low load operations.

Innovation Solution

A cooling system with a radiator, bypass route, changeover device, heat radiation varying device, and control unit that adjusts the flow of cooling water through both radiator and bypass routes based on temperature and load conditions to optimize the flow rate and heat transfer, ensuring the engine operates within a safe temperature range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the thermostat is closed to lower the cooling water temperature during high load operation, then the temperature control is improved, but the pressure loss increases and the cooling water flow rate decreases

Engineering Contradiction:
Improvecooling water temperatureVSAvoidcooling water flow rate
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The system dynamically switches between two cooling modes (thermostat closed/open) based on engine load conditions. During high load operation, the thermostat is closed to maintain temperature, while during low load operation, it opens to maximize flow rate, optimizing both temperature control and cooling efficiency at different operating points

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the thermal parameter (heat radiation amount from radiator) based on engine load conditions. The control unit adjusts the radiator's heat radiation to compensate for reduced cooling water flow rate when thermostat is closed, maintaining effective cooling during high load operation

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If the cooling water flow rate is increased to suppress knocking during high load operation, then the knocking suppression is improved, but the temperature control efficiency decreases

Engineering Contradiction:
Improveknocking occurrenceVSAvoidcooling water temperature control
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The system changes the thermal parameter (heat radiation amount) of the radiator based on engine load. During high load operation, the control unit increases heat radiation from the radiator to enhance cooling effect, allowing the thermostat to remain closed while still effectively suppressing knocking through increased radiative heat transfer

Inventive Principle:
Principle #35Parameter changes

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 system effectively maintains a proper flow rate of cooling water, reducing the risk of knocking during high load operations and improving fuel efficiency by adjusting the heat radiation amount, thereby preventing overheating and optimizing thermal efficiency.

Implementation Method 1

a radiator (13) for releasing or radiating the heat from the cooling water

Methodology Applied
Scientific EffectHeat radiation: Thermal Radiation

Implementation Method 2

the temperature of the combustion chamber is raised during the high load operation of the internal combustion engine

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3224461B1Cooling system for internal combustion engine
Publication Date: 2020.04.01 TOYOTA JIDOSHA KK
  • EP3224461B1 patent drawingFigure 1~2
  • EP3224461B1 patent drawingFigure 3
  • EP3224461B1 patent drawingFigure 4~5

AI summary

A heat radiation amount from the cooling water in the radiator is adjusted so that the temperature of the cooling water is less than a prescribed temperature that is a temperature higher than the threshold value if a load exerted on the internal combustion engine is not less than a predetermined load, while the heat radiation amount from the cooling water in the radiator is adjusted so that the heat radiation amount from the cooling water in the radiator is increased if the load exerted on the internal combustion engine is less than the predetermined load as compared with if the load exerted on the internal combustion engine is not less than the predetermined load.