Vehicle Fluid System Thermal Diagnostic Method
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Solution Overview
Problem
Conventional vehicle fluid systems lack an effective method to determine the fluid level without a fluid level sensor, which can lead to inadequate lubrication and cooling, potentially causing component overheating and failure.
Innovation Solution
A diagnostic method using temperature sensors for both the vehicle component and fluid system, where a controller compares the temperature difference between the component and fluid to a predetermined threshold value to output a diagnostic code or flag indicative of a low fluid level, allowing for alerting the driver and adjusting vehicle operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fluid level sensor is used to determine fluid level, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical fluid level sensor with a thermal-based diagnostic system using temperature sensors and controller logic. The controller determines fluid level by comparing temperatures from component and fluid temperature sensors, eliminating the need for direct mechanical contact with the fluid while maintaining detection capability.
Solution Approach 2:
The patent introduces temperature difference as an intermediary parameter to indirectly determine fluid level. Instead of directly measuring fluid level, the system measures component temperature and fluid temperature, calculates their difference, and uses this temperature difference as a proxy indicator for fluid level condition.
2Device complexity
If temperature difference method is used to detect fluid level, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The system continuously monitors component temperature and fluid temperature, calculates the temperature difference, and compares it against expected ranges. This feedback mechanism allows the controller to dynamically assess fluid level conditions and trigger appropriate warnings or adjustments, improving the reliability of the indirect measurement method.
Solution Approach 2:
The patent changes the measurement parameter from direct fluid level (physical height) to temperature difference (thermal property). By monitoring how temperature differential changes with fluid level, the system translates an indirect thermal measurement into meaningful fluid level information through established thermal relationships.
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 method enables the detection of low fluid levels without a physical sensor, preventing overheating and ensuring proper lubrication and cooling, thus extending component lifespan and maintaining vehicle performance.
Implementation Method 1
A component temperature sensor is connected to the electric machine to measure a temperature of the electric machine
Implementation Method 2
The fluid system has a fluid temperature sensor to measure a temperature of the lubricant
Implementation Method 3
The controller is configured to, in response to a temperature difference between the component temperature sensor and the fluid temperature sensor being greater than a predetermined threshold value, output a diagnostic code indicative of the lubricant in the fluid system being less than a predetermined fluid level
Data Source
AI summary
A vehicle system includes a vehicle component with a component temperature sensor, and a fluid circuit in fluid communication with the component and with a fluid temperature sensor. A controller is in communication with the component sensor and the fluid sensor. The controller is configured to, in response to a temperature difference between the component sensor and the fluid sensor being greater than a predetermined threshold value, output a flag or a diagnostic code indicative of a fluid level in the fluid circuit. A vehicle diagnostic method and a vehicle are also provided.