Rear Air Filter Temperature Sensor Diagnosis
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Solution Overview
Problem
Current methods lack a reliable failure diagnosis mechanism for temperature sensors placed at the rear stage of an air filter in engine rooms, which is crucial for the effective operation of EGR systems, particularly in LP-EGR technology, where pressure differences are minimal and temperature sensors like MAF are not traditionally used for diagnosis.
Innovation Solution
A method involving the comparison of a heating condition factor, calculated based on engine room heat generation, with a threshold, to determine deviations between intake manifold and intake air temperatures, allowing for the diagnosis of failing temperature sensors at the rear stage of the air filter, using intake manifold and intake air temperature sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a temperature sensor is installed at the rear stage of the air filter to enable condensate calculation for EGR system operation, then the EGR system can be used under more conditions and fuel efficiency improves, but the temperature sensor may fail without a diagnosis mechanism
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring the temperature sensor output and comparing it with expected temperature ranges and heating condition factors. When the sensor reading deviates from the expected range, the system generates a failure diagnosis signal, allowing the ECU to detect and respond to sensor failures automatically.
Solution Approach 2:
The temperature sensor diagnosis system performs self-service by using its own output signal and comparing it against predetermined criteria (heating condition factors, temperature thresholds) to automatically detect its own failure condition without requiring external manual testing or additional complex diagnostic equipment.
2Device complexity
If no temperature sensor is used at the rear stage of the air filter, then the system complexity is reduced and no failure diagnosis is needed, but condensate calculation cannot be performed and EGR system usage is limited
Solution Approach 1:
The patent replaces the need for complex mechanical diagnostic equipment with an electronic/software-based diagnosis system. The ECU uses software algorithms to compare temperature readings against heating condition factors and generate failure diagnoses, substituting mechanical testing methods with electronic signal processing and computational analysis.
3Measurement precision
If a temperature sensor is installed for condensate calculation, then accurate EGR control is achieved, but the sensor requires failure diagnosis logic implementation
Solution Approach 1:
The patent applies partial action by implementing a simplified diagnosis approach that checks temperature readings against predetermined heating condition factors and thresholds. Rather than implementing comprehensive continuous monitoring, the system performs diagnosis based on specific conditions (comparing temperature differences during specific operating conditions), reducing the complexity of the diagnosis logic while maintaining effective failure detection.
Data Source
AI summary
A method of diagnosing a temperature sensor provided at a rear stage of an air filter includes: comparing a heating condition factor with a factor threshold; when the heating condition factor is less than the factor threshold, calculating a deviation between a temperature of an intake manifold and a temperature of intake air at a rear stage of an air filter; comparing a temperature threshold with the deviation; and, when the deviation exceeds the temperature threshold, diagnosing the intake air temperature sensor provided at the rear stage of the air filter as failing. According to the method, failure of a temperature sensor provided at a rear state of an air filter of an engine room can be diagnosed.