Wire Harness Temperature Estimation for Vehicle Overheat Shutoff
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Solution Overview
Problem
In vehicles, accurately estimating the temperature of wire harnesses in the front area, which is influenced by engines or motors, is challenging due to varying environmental conditions, leading to potential overheating or underheating issues, and existing methods require multiple temperature sensors or complex simulations, increasing costs and man-hours.
Innovation Solution
A vehicle control device with a current detection element, standard temperature generation unit, temperature estimation unit, and shutoff element that uses a combination of predetermined temperature sensors and vehicle state information to calculate an accurate standard temperature for wire harness temperature estimation, allowing for reliable overheating protection without excessive current limitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are installed in the vicinity of wire harnesses to acquire standard temperature, then temperature estimation accuracy is improved, but component cost and installation man-hours increase
Solution Approach 1:
The patent introduces air temperature and engine temperature as intermediary parameters to represent the environmental temperature conditions affecting the wire harness. Instead of directly measuring wire harness temperature with sensors, the system uses these intermediary temperature values from existing sensors to calculate the standard temperature through a relational expression, thereby avoiding direct installation of temperature sensors on wire harnesses while still achieving accurate temperature estimation.
Solution Approach 2:
The patent creates a thermal model that copies the heat generation and dissipation characteristics of the wire harness through mathematical relationships. By modeling the wire harness temperature based on current values, air temperature, and engine temperature, the system replicates the thermal behavior without physical contact, eliminating the need for direct temperature sensing on the wire harness itself.
2Measurement precision
If multiple temperature sensors are installed to accurately measure environmental temperature, then temperature measurement accuracy is improved, but manufacturing cost and installation time increase
Solution Approach 1:
The patent makes existing temperature sensors (air temperature sensor and engine temperature sensor) serve multiple functions. These sensors originally designed for other purposes are now also used to provide data for wire harness temperature estimation, eliminating the need for dedicated temperature sensors on wire harnesses and reducing both component cost and installation time.
Solution Approach 2:
The system uses already-installed temperature sensors in the vehicle to serve the additional function of wire harness temperature monitoring. By leveraging existing sensor infrastructure and combining it with current detection and thermal modeling, the system achieves temperature estimation without requiring additional sensor installations, thereby reducing installation time and complexity.
3Power
If standard temperature is set too high to avoid false shutoff, then current supply capability is improved, but wire harness overheating protection reliability decreases
Solution Approach 1:
The patent implements dynamic adjustment of the standard temperature based on real-time operating conditions. The standard temperature is not fixed but is calculated dynamically using a relational expression that incorporates air temperature, engine temperature, and current values. This allows the system to adapt the temperature threshold to actual environmental conditions, preventing false shutoffs while maintaining reliable overheating protection.
Solution Approach 2:
The system continuously monitors current values, air temperature, and engine temperature, and uses this feedback to dynamically calculate and adjust the standard temperature. This closed-loop approach ensures that the temperature threshold accurately reflects real-time thermal conditions, maintaining both current supply capability and protection reliability by adjusting the threshold based on actual operating conditions rather than using a fixed conservative value.
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 enables accurate temperature estimation and reliable overheating protection for wire harnesses, reducing the need for multiple sensors and minimizing current limitations, thus enhancing safety and efficiency while reducing component and installation costs.
Implementation Method 1
an amount of temperature rise caused by self-heating of the wire harness by the current
Implementation Method 2
a relational expression regarding the detected energizing current and the heat dissipation/heat generation of the electric wire
Data Source
AI summary
Included are: a current detection element which detects a current flowing through a wire harness which supplies power to in-vehicle equipment mounted on a vehicle; a standard temperature generation unit which obtains a standard temperature by using a predetermined value or a detection value of a predetermined temperature sensor among a plurality of temperature sensors mounted on the vehicle; a temperature estimation unit which estimates a temperature of the wire harness by using a current detection value and a standard temperature value; a shutoff determination unit which makes a shutoff determination on the basis of the estimated temperature; and a shutoff element which shuts off the current flowing through the wire harness on the basis of the determination made by the shutoff determination unit. This enables vehicle control without a dedicated temperature sensor.