Electric Propulsion Cooling Layout With Series Water Jackets

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Solution Overview

Problem

Existing electric propulsion devices face challenges in efficiently cooling multiple components like motors and inverters while maintaining a simple structural design, as providing separate cooling water supply and discharge passages for each component complicates the device.

Innovation Solution

The electric propulsion device integrates a series connection of motor and inverter water jackets with a shared intake and drain port, utilizing a single pump to circulate cooling water through both jackets, simplifying the structure and enhancing cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate cooling water supply and discharge passages are provided for each component (motor and inverter), then each component can be cooled independently, but the device structure becomes complicated

Engineering Contradiction:
Improvecooling efficiencyVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the cooling passages of the motor and inverter into a single integrated water jacket structure. The cooling water supply passage and discharge passage are shared between both components, allowing simultaneous cooling of the motor and inverter without requiring separate independent cooling systems. This reduces the number of passages and simplifies the overall device structure while maintaining effective cooling of both heat-generating components.

Inventive Principle:
Principle #5Merging (Combining)

2Temperature

If multiple independent cooling systems are used for motor and inverter, then each component receives adequate cooling, but the number of passages and components increases

Engineering Contradiction:
Improvecooling performanceVSAvoidnumber of passages
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling water supply passage and discharge passage are designed to serve multiple functions by simultaneously cooling both the motor and inverter. The water jacket structure is configured so that cooling water flows through passages that contact both components, allowing a single cooling system to perform the cooling function for multiple heat-generating components rather than requiring separate dedicated cooling systems for each.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration allows for efficient cooling of both the motor and inverter with a simplified structure, reducing complexity and enhancing thermal management without the need for additional branching passages.

Implementation Method 1

a pump configured to flow the cooling water from the intake port to the drain port in the electric propulsion device

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 2

a motor water jacket configured to cool the motor with cooling water taken into the electric propulsion device, and an inverter water jacket configured to cool the inverter with cooling water taken into the electric propulsion device

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP4707163A1Electric propulsion device
Publication Date: 2026.03.11 SUZUKI MOTOR CORP
  • EP4707163A1 patent drawingFigure 1
  • EP4707163A1 patent drawingFigure 2
  • EP4707163A1 patent drawingFigure 3

AI summary

An electric propulsion device includes a propeller, a motor rotating the propeller, an inverter controlling driving of the motor, and a cooling device cooling the motor and the inverter. The cooling device includes an intake port taking water around the electric propulsion device into the electric propulsion device as cooling water, a drain port discharging the cooling water taken into the electric propulsion device to around the electric propulsion device, a pump flowing the cooling water from the intake port to the drain port in the electric propulsion device, a motor water jacket cooling the motor with cooling water taken into the electric propulsion device, and an inverter water jacket cooling the inverter with cooling water taken into the electric propulsion device. The motor water jacket and the inverter water jacket are connected in series between the intake port and the drain port in the electric propulsion device.