Vehicle Wire Bundle Temperature Estimation via Load Current Feedback
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Solution Overview
Problem
Existing technologies fail to accurately estimate the temperature of electric wires bundled in a vehicle, leading to potential delays in reaching the upper limit temperature, which can result in unintended smoke or damage due to heat from other wires.
Innovation Solution
An electric-wire protection device with a switch portion, current detection portion, calculation circuit, and protection circuit that estimates the temperature of an electric wire by correcting the initial temperature based on load current and thermal characteristics, and shuts off power when the temperature reaches a specified limit, accounting for heat generation from other wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If electric wires are bundled and installed in a vehicle, then space utilization is improved, but temperature estimation accuracy deteriorates due to heat from other wires
Solution Approach 1:
The system continuously monitors current flow information from all loads and feeds this data back to the calculation circuit. The calculation circuit uses this feedback to dynamically correct the initial temperature and recalculate the subject wire's temperature, ensuring accurate temperature estimation despite heat from bundled wires.
Solution Approach 2:
The calculation circuit acts as an intermediary that processes current flow information from all loads and translates it into a correction value for the initial temperature. This intermediary function allows the system to account for heat from other wires without requiring direct temperature sensing of each wire.
2Device complexity
If conventional temperature estimation is used for bundled wires, then device complexity is reduced, but protection reliability deteriorates due to delayed temperature limit detection
Solution Approach 1:
The system performs preliminary correction of the initial temperature by calculating the temperature contribution from all other loads before estimating the subject wire's temperature. This preliminary action ensures that the temperature estimation starts from an accurate baseline, preventing delayed detection of the upper limit temperature.
Solution Approach 2:
The protection circuit receives continuous feedback on the corrected temperature estimation and compares it against the upper limit. This feedback mechanism ensures reliable protection by immediately detecting when the corrected temperature reaches the limit, even in bundled wire configurations.
3Measurement precision
If current flow information from other loads is supplied to the calculation circuit, then temperature estimation accuracy is improved, but device complexity increases
Solution Approach 1:
The calculation circuit is designed to perform multiple functions: it calculates the subject wire's temperature increase, corrects the initial temperature using current flow information from all loads, and determines the corrected temperature. This multi-functionality improves accuracy without requiring separate dedicated circuits for each function.
Solution Approach 2:
The system merges the temperature calculation and correction functions into a single calculation circuit. By combining these functions, the patent achieves accurate temperature estimation while minimizing device complexity through functional integration rather than multiplication of separate components.
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 solution ensures reliable electric-wire protection by accurately estimating the temperature of bundled wires, reducing the impact of heat from other wires and preventing damage by promptly shutting off power when the temperature reaches the limit.
Implementation Method 1
calculates an increased temperature of the electric wire from an initial temperature that exists at the time that an estimate begins, based on the load current that has been detected and a thermal characteristic of the electric wire
Implementation Method 2
the actual electric-wire temperature (actual temperature) may be higher than the estimated temperature due to heat from the other electric wires
Data Source
AI summary
An electric-wire protection device protects at least one electric wire among an electric-wire bundle that bundles a plurality of electric wires that are used to supply power to a plurality of loads from a power source Ba. Calculation circuit calculates an increased temperature of the electric wire from an initial temperature at the time that the estimate begins, based on a load current Is that has been detected and a thermal characteristic of the electric wire, and estimates the temperature of the electric wire by adding the increased temperature to the initial temperature. Current flow information supply portion supplies to the calculation circuit current flow information related to current flow to a load other than a subject load. Calculation circuit corrects the initial temperature by a correction value that corresponds to the current flow information that exists at the time the estimate begins.