Multi-Radiator Cooling Circuit With Pressure-Switched Flow Split

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Solution Overview

Problem

Existing cooling systems for fuel cell electric vehicles (FCEVs) struggle to manage high heat loads during high load conditions, often requiring complex and costly multiple radiator setups with increased energy consumption and failure risks, which are not suitable for heavy-duty commercial applications.

Innovation Solution

A cooling system with a main circuit line and an auxiliary circuit line, featuring a pressure valve that passively switches between states based on working pressure to distribute coolant flow between multiple heat exchangers, minimizing energy losses and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single radiator is used for cooling, then the system complexity is low, but the cooling capacity is insufficient during high load conditions

Engineering Contradiction:
Improvecooling system complexityVSAvoidcooling capacity
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The cooling system is segmented into a main cooling circuit and an auxiliary cooling circuit, allowing independent operation of each circuit. The main circuit handles normal cooling requirements while the auxiliary circuit provides additional cooling capacity during high load conditions, resolving the contradiction between system simplicity and cooling performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between single-radiator operation and dual-radiator operation based on cooling demand. A control unit activates the auxiliary circuit and three-way valve only when high cooling capacity is required, allowing the system to adapt its complexity to actual needs rather than maintaining fixed high complexity.

Inventive Principle:
Principle #15Dynamics

2Temperature

If multiple radiators are used to increase cooling capacity, then the temperature management improves, but the system complexity and control requirements increase

Engineering Contradiction:
Improvecooling capacityVSAvoidcontrol system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

A three-way valve acts as an intermediary component that automatically directs coolant flow between the main radiator and auxiliary radiator based on temperature sensor feedback. This intermediary mechanism simplifies control by using passive flow distribution rather than requiring active control of multiple valves.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The auxiliary cooling circuit includes its own pump and temperature sensor that autonomously monitor and regulate auxiliary radiator operation. This self-service capability reduces the burden on the main control system, allowing independent operation of the auxiliary circuit and simplifying overall control architecture.

Inventive Principle:
Principle #25Self-service

3Temperature

If multiple radiators with complex control are used, then the cooling capacity increases, but the energy consumption and failure risk increase

Engineering Contradiction:
Improvecooling capacityVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The auxiliary cooling circuit operates partially only when high cooling capacity is required, rather than continuously. The control unit monitors temperature and activates the auxiliary pump and valve only during high load conditions, reducing energy consumption compared to having the auxiliary system always active.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The auxiliary pump is designed as a simple, reliable component that can be easily replaced if needed, rather than a complex high-efficiency pump. This approach prioritizes reliability and ease of maintenance over maximum efficiency, reducing failure risk and associated energy losses from system downtime.

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

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 effectively manages heat loads by adaptively distributing coolant flow without complex control strategies, reducing energy consumption and component failure risks, while maintaining reliable cooling performance.

Implementation Method 1

comprising a pump for pressurizing the main circuit line at a working pressure to generate a flow of coolant from the component towards the main heat exchanger

Methodology Applied
Scientific EffectPressurisation: Pressurisation

Implementation Method 2

The first auxiliary circuit line comprises a pressure valve that is passively operable by the pump adapting the working pressure in the main circuit line

Methodology Applied
Scientific EffectPressure-dependent valve operation: Pressure Gradient

Implementation Method 3

a main heat exchanger... a first auxiliary heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4531145B1Commercial vehicle comprising a multi radiator cooling system
Publication Date: 2026.01.28 DAF TRUCKS NV
  • EP4531145B1 patent drawingFigure 1
  • EP4531145B1 patent drawingFigure 2
  • EP4531145B1 patent drawingFigure 3

AI summary

A commercial vehicle (10), comprising an electric drive unit (100) and a cooling system (200). The cooling system comprises a main circuit line (210) with a pump (212) for pressurizing the main circuit line at a working pressure. An auxiliary circuit line (220) extends from the main circuit line downstream of the pump towards a first auxiliary heat exchanger (221), and comprises a pressure valve (213) that is passively operable between a first state and a second state by the pump adapting the working pressure in the main circuit line. In response to a temperature of the electric drive unit exceeding a temperature threshold, the pump increases the working pressure for thereby operating the pressure valve to switch from the first state to the second state.