Fuel Cell Cooling Pipe Layout for Earthwork Machine Insulation
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Solution Overview
Problem
Earthwork machines, such as dump trucks, require a high insulation resistance of 1 MΩ or more between the electric power circuit and equipotential bonding circuit, which is challenging to achieve with a fuel cell due to its low insulation resistance.
Innovation Solution
The configuration includes a housing for the fuel cell electrically connected to the vehicle body, with a refrigerant pipe penetrating the housing and insulated from it, allowing the refrigerant to flow externally and connect to the vehicle body, ensuring a high insulation resistance through a frame-grounded circulation pump and radiator, and using isolated DC/DC converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a fuel cell is mounted on the earthwork machine, then clean energy power supply is achieved, but the insulation resistance between electric power circuit and equipotential bonding circuit becomes insufficient
Solution Approach 1:
The patent segments the electrical system into isolated units: the fuel cell is housed in a separate housing electrically connected to the equipotential bonding circuit, while the DC/DC converter and its associated refrigerant circulation system form an isolated electrical unit. This segmentation prevents direct electrical contact between the fuel cell and the vehicle body, thereby maintaining the required insulation resistance while enabling clean energy power supply.
Solution Approach 2:
The patent introduces an intermediary refrigerant circulation system as a mediator between the fuel cell and the vehicle body. The refrigerant pipe penetrates the housing and connects the fuel cell to the DC/DC converter without providing an electrical conduction path. This intermediary system enables thermal management and operational control while preserving electrical insulation, thus resolving the contradiction between functional integration and insulation requirements.
2Reliability
If the refrigerant pipe is made long to ensure insulation resistance, then insulation performance improves, but device complexity and space requirements increase
Solution Approach 1:
The patent extracts the refrigerant circulation path from the housing structure, allowing the refrigerant pipe to extend externally from the housing to connect with the DC/DC converter. This external routing provides sufficient insulation distance without requiring excessive pipe length within the housing, thereby achieving the required insulation resistance while minimizing device complexity and space occupation.
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 achieves the required high insulation resistance, securing the insulation resistance for each fuel cell unit and the entire electric system, while reducing the need for excessive pipe lengths and maintaining efficient operation.
Implementation Method 1
a refrigerant pipe penetrating the housing, allowing a refrigerant to flow from the outside of the housing to the fuel cell
Implementation Method 2
electrically insulated from the housing, and configured such that the refrigerant and the vehicle body are electrically connected to each other
Data Source
AI summary
An earthwork machine includes a vehicle body, a fuel cell, a housing, and a refrigerant pipe. The housing stores the fuel cell and is electrically connected to the vehicle body. The refrigerant pipe penetrates the housing and allows a refrigerant to flow from the outside of the housing to the fuel cell. The refrigerant pipe is electrically insulated from the housing and is configured such that the refrigerant and the vehicle body are electrically connected to each other on the outside of the housing.