Engine Cooling System with Bypass Branch for Rapid Warm-Up

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing cooling systems for internal combustion engines take too long to reach optimal operating temperature during cold starts, leading to increased fuel consumption and pollutant emissions.

Innovation Solution

A cooling system with a heat exchange section connected to two heat exchangers, controlled by valves that allow the heat transfer fluid to circulate in a main branch and a bypass branch, enabling efficient heat exchange between burned gases and fresh intake air, and incorporating a temperature probe to switch between preheating and normal operating states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the heat transfer fluid circulates through the heat exchange section during cold start, then the engine temperature rises more quickly, but the heat exchangers experience localized hot spots and reduced heat exchange efficiency

Engineering Contradiction:
Improveengine temperatureVSAvoidheat exchanger performance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The system dynamically switches between two operational modes using controllable valves: during cold start, the bypass branch is activated to prevent hot spots while still enabling heat transfer to the engine; during normal operation, the heat exchange section is activated for efficient heat recovery. This dynamic configuration resolves the contradiction by adapting the system structure to operational conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The cooling system is segmented into two independent branches: a heat exchange section for normal operation and a bypass branch for cold start conditions. This segmentation allows each branch to be optimized for its specific function, preventing the heat exchangers from experiencing thermal shock and localized hot spots during cold start while maintaining efficient heat recovery during normal operation.

Inventive Principle:
Principle #1Segmentation

2Temperature

If the heat transfer fluid circulates in the main branch only, then the heat exchangers are protected from thermal stress, but the engine takes too long to reach optimal operating temperature

Engineering Contradiction:
Improveengine temperatureVSAvoidtime to reach optimal temperature
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

The system uses controllable valves to dynamically route the heat transfer fluid through different branches based on engine temperature. During cold start, the bypass branch is opened to provide rapid heating; once the engine reaches optimal temperature, the system switches to the heat exchange section for efficient heat recovery. This dynamic switching resolves the time-loss contradiction.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The bypass branch is pre-configured to provide immediate heat transfer to the engine during cold start, before the heat exchangers are fully operational. This preliminary heating action gets the engine to optimal temperature quickly, after which the system transitions to normal heat exchange mode.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the heat transfer fluid circulates through both the main branch and bypass branch simultaneously, then the engine reaches optimal temperature quickly, but the system complexity increases

Engineering Contradiction:
Improveheating efficiencyVSAvoidcooling system structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Rather than simultaneously activating both branches, the system uses dynamic control to switch between branches based on engine temperature. Two controllable valves manage the routing: during cold start, the bypass branch is activated; during normal operation, the heat exchange section is activated. This dynamic approach achieves rapid heating when needed without the complexity of simultaneous multi-branch operation.

Inventive Principle:
Principle #15Dynamics

4Temperature

If a single cooling circuit is used, then the system is simple, but the engine cannot reach optimal temperature quickly during cold start

Engineering Contradiction:
Improveengine temperatureVSAvoidcooling system structure
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling system is divided into two functional branches: a heat exchange section for normal operation and a bypass branch for cold start. This segmentation enables the system to provide rapid heating during cold start while maintaining efficient heat recovery during normal operation, achieving improved temperature response with only moderate increases in system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from a static single-circuit design to a dynamic multi-branch configuration with controllable valves. This allows the system to adapt its structure to operational needs, providing rapid heating during cold start and efficient heat recovery during normal operation, thereby achieving improved temperature response with acceptable complexity.

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 solution quickly raises the engine and lubricant temperatures, reducing fuel consumption and emissions by optimizing combustion and depollution, while avoiding localized hot spots through a closed fluid circulation loop.

Implementation Method 1

a heat exchange section which serves the two heat exchangers, said heat exchange section having two ends, each of the two ends being connected to a valve

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

The heat transfer fluid then circulates around the cylinders and releases some of the recovered heat to them

Methodology Applied
Scientific EffectThermal energy transfer: Conduction (thermal)

Implementation Method 3

The burnt gases enter one of the heat exchangers at high temperature through one of the two gas circulation lines. The fresh intake air enters the other heat exchanger at low temperature through the other of the two gas circulation lines. These two types of gases can exchange heat thanks to the heat transfer fluid that circulates in the two exchangers

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3864269B1Cooling system for a combustion engine and method of controlling the same
Publication Date: 2024.01.17 RENAULT SA
  • EP3864269B1 patent drawingFigure 1~2
  • EP3864269B1 patent drawingFigure 3~4
  • EP3864269B1 patent drawingFigure 5~6

AI summary

The invention relates to a cooling system (39) for an internal combustion engine (1) comprising two gas-circulation lines (7, 9), the said cooling system (39) comprising two heat exchangers (17, 35) connected to the two gas-circulation lines (7, 9), and a circuit (55) through which heat-transfer fluid circulates and which comprises: – a heat-exchange portion (37) serving the heat exchangers and having two ends, each one being connected to a valve, – a main leg (91) connected to the valves and serving the engine, – a bypass leg (83) connected to the valves, and said cooling system (39) further comprising: – a controller (77) able to control the valves, between a state of normal operation in which the valves allow the heat-transfer fluid to circulate in the main leg and the heat-exchange portion, and a preheat state in which the two valves allow the heat-transfer fluid to circulate in the main leg and the bypass leg. The invention also relates to a method for controlling the cooling system.