Vehicle Temperature Sensor Diagnosis Using Fuel Temperature Mediator
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Solution Overview
Problem
Conventional diagnostic methods for temperature sensors in vehicles face inaccuracies due to reliance on single fixed reference values and failure to account for varying conditions, leading to erroneous determinations of thermal equilibrium state, especially in rapid cooling conditions.
Innovation Solution
A diagnostic apparatus utilizing a fuel temperature sensor to determine the state of a temperature sensor by measuring variations in fuel temperature after engine startup, with thresholds for increments and decrements, and comparing these to criterial values, to accurately assess the thermal equilibrium state and fault conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the water temperature and oil temperature are used to determine thermal equilibrium state, then the diagnosis can be performed without a soak timer, but the diagnostic accuracy deteriorates under rapid cooling conditions
Solution Approach 1:
The patent introduces fuel temperature as an intermediary parameter to determine thermal equilibrium state. Instead of directly using water temperature or oil temperature which are affected by rapid cooling, the fuel temperature serves as a mediator that reflects the ambient temperature more accurately. The diagnostic unit compares the difference between water temperature and fuel temperature, or oil temperature and fuel temperature, to determine thermal equilibrium, thereby avoiding the harmful effect of rapid engine cooling on diagnostic accuracy.
2Device complexity
If a fixed reference value is used to determine thermal equilibrium, then the diagnostic method is simple, but the diagnostic accuracy deteriorates due to varying initial temperatures and ambient conditions
Solution Approach 1:
The patent transitions from a static fixed reference value approach to a dynamic comparison approach. Instead of using a predetermined fixed time value or fixed temperature difference threshold, the system dynamically determines thermal equilibrium by comparing the temperature difference between engine components (water temperature, oil temperature) and the fuel temperature. This dynamic adaptation allows the diagnostic system to accurately determine thermal equilibrium state under varying initial temperatures and ambient conditions, thereby improving diagnostic accuracy while maintaining relative simplicity.
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
Improves diagnostic accuracy by differentiating between normal and faulty temperature sensor states, reducing misdiagnoses and providing reliable assessments even under rapid cooling conditions.
Implementation Method 1
The fuel temperature sensor measures a fuel temperature in the vehicle. The fuel temperature is different from the first temperature.
Implementation Method 2
The first temperature sensor measures a first temperature of an object related to an engine in the vehicle
Implementation Method 3
Both the temperature of cooling water for the engine measured with a water temperature sensor and the temperature of the engine oil measured with an oil temperature sensor are close to the ambient temperature after the engine reaches a thermal equilibrium state
Data Source
AI summary
A first temperature sensor measures a first temperature of an object related to an engine. A fuel temperature sensor measures a fuel temperature. A diagnostic apparatus includes a diagnostic unit diagnosing the first temperature sensor based at least in part on the first temperature measured at the first temperature sensor. The diagnostic apparatus also includes a first determining unit determining whether the state of fault of the first temperature sensor is unclear or not based at least in part on the variation in the fuel temperature after the start-up of the engine for the diagnosis at the diagnostic unit.