Differential Carrier Temperature Sensing via Fluid Thermal Copy
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Solution Overview
Problem
Current temperature sensing methods for vehicle differentials are inadequate due to high costs and the use of slow responding sensors, which fail to accurately detect potential failures in the harsh differential environment, leading to reduced reliability and effectiveness in monitoring thermal conditions.
Innovation Solution
A differential carrier temperature sensing package that utilizes a combination of temperature sensors, thermal conductors, and electronic circuits to accurately determine internal temperatures within the differential carrier, using thermal conduction and resistance calculations to provide real-time monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are disposed directly in the differential to measure internal conditions, then measurement precision is improved, but device complexity and cost increase due to sealing requirements in the harsh differential environment
Solution Approach 1:
The patent uses the differential fluid as an intermediary medium to transfer thermal information from the internal differential environment to external sensors. Instead of placing sensors directly inside the differential carrier, the system measures the temperature of the fluid that circulates through the differential, which accurately reflects the internal thermal conditions without requiring complex sealing mechanisms.
Solution Approach 2:
The patent creates a thermal copy of the internal differential environment by measuring the fluid temperature that is thermally coupled to the differential carrier. This fluid temperature measurement serves as an accurate representation or copy of the internal conditions, allowing external sensors to monitor internal thermal states without physical intrusion into the sealed differential environment.
2Reliability
If slow responding sensors are used to monitor differential temperature, then device complexity is reduced, but reliability deteriorates due to delayed failure detection
Solution Approach 1:
The patent extracts the temperature sensing function from the harsh internal differential environment and places it in the external fluid circulation system. By measuring the fluid temperature outside the sealed differential carrier, the system achieves fast response times for failure detection without the complexity of protecting sensors from the high-temperature, high-vibration differential environment.
Solution Approach 2:
The differential fluid serves as a thermal intermediary that rapidly transmits temperature information from the differential carrier to external sensors. This mediator approach enables fast response times because the fluid continuously circulates and quickly equilibrates with the differential carrier temperature, allowing external sensors to detect thermal changes immediately without being exposed to the harsh internal environment.
3Measurement precision
If sensors are placed directly in the differential carrier, then measurement precision is improved, but the harsh environment reduces sensor durability and reliability
Solution Approach 1:
The patent employs the differential fluid as a thermal intermediary that bridges the internal differential environment and external sensing system. The fluid is already present in the differential environment and continuously contacts the differential carrier, so measuring its temperature provides accurate internal temperature data without exposing sensors to the harsh conditions of high temperature, vibration, and contamination.
Solution Approach 2:
The system creates an external thermal copy of the internal differential conditions by measuring the fluid temperature that is thermally coupled to the differential carrier. This approach replicates the internal thermal state in the external fluid environment, allowing accurate temperature monitoring without placing sensors directly in the harsh internal environment where they would suffer from reduced durability.
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 quick and accurate determination of internal differential carrier temperatures, enhancing the reliability and operational efficiency of vehicle differentials by providing timely failure detection and improved monitoring capabilities.
Implementation Method 1
The lower portion is also in thermally conductive contact with an outer surface of the differential carrier housing, where the lower portion of the differential package housing extends through an opening in the differential housing, thereby being in thermally conductive contact with a fluid within the differential housing
Data Source
AI summary
A method of sensing an internal temperature of a differential carrier includes providing a differential carrier temperature sensing package with an electronic circuit board having a first temperature sensor that is in thermally conductive contact with a thermal conductor, where the thermal resistance of the package and thermal conductor is given and known as RENC. The package is extended through an opening in a differential carrier that has a fluid in it. The first temperature sensor senses a differential fluid temperature TSNS. The electronic circuit board further has a second temperature sensor, whereby the thermal resistance of the circuit board is a given known resistance RPCB. The second temperature sensor senses an internal package temperature TPCB within the package. Consequently, an internal temperature of the differential is calculated from the equation:TINT=TSNS(1+RENC/RPCB)−TPCB(RENC/RPCB).