Tank-Venting Pressure Sensor Diagnosis for Fault Differentiation
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Solution Overview
Problem
Existing pressure sensor diagnosis methods in tank venting systems of internal combustion engine vehicles fail to accurately distinguish between pressure sensor faults and purge line faults, leading to incorrect system functionality assessments.
Innovation Solution
A method and device for pressure sensor diagnosis that categorizes pressure readings into different ranges and uses a diagnosis algorithm to differentiate between pressure sensor faults and purge line faults without actively interfering with the tank venting function, allowing for precise identification of faulty components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor diagnosis is performed using existing methods, then the system can detect pressure sensor faults, but it cannot accurately distinguish between pressure sensor faults and purge line faults
Solution Approach 1:
The diagnosis method is segmented into multiple evaluation stages: initial pressure change detection, secondary evaluation based on pressure development over time, and tertiary evaluation using pressure gradient analysis. Each segment addresses specific fault scenarios, enabling precise differentiation between pressure sensor faults and purge line faults through progressive refinement of diagnostic criteria.
2Reliability
If the tank venting valve is actively actuated for diagnosis, then pressure sensor functionality can be tested, but the tank venting function is disrupted affecting driveability and emissions
Solution Approach 1:
The system uses naturally occurring pressure changes during normal tank venting operation to perform self-diagnosis. The pressure sensor and control unit evaluate pressure developments during routine valve actuation for regeneration purposes, enabling automatic fault detection without additional active actuation cycles. This allows the system to monitor its own functionality while maintaining normal purge operations.
Solution Approach 2:
The diagnosis is performed continuously during normal tank venting operations rather than requiring separate diagnostic cycles. The pressure sensor continuously monitors pressure changes, and the control unit continuously evaluates these changes against diagnostic criteria, ensuring that the useful action of purging fuel vapors continues uninterrupted while diagnostic evaluation proceeds simultaneously.
3Measurement precision
If pressure changes are actively introduced for diagnosis, then sensor functionality can be assessed, but the system requires interruption of competing diagnosis functions
Solution Approach 1:
The pressure sensor diagnosis is merged with the lambda probe diagnosis and catalyst diagnosis functions. The control unit simultaneously evaluates pressure developments for multiple diagnostic purposes during the same operational period, eliminating the need to interrupt other diagnosis functions. This integration allows concurrent execution of multiple diagnostic tasks without time loss.
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
Enables accurate differentiation between pressure sensor faults and purge line faults without disrupting the tank venting system, maintaining high purge rates and avoiding impacts on driveability and emissions.
Implementation Method 1
a pressure sensor arranged in the purge line (13) between the activated carbon filter (3) and the tank venting valve (6) is designed to carry out a line diagnosis of the full-load venting path (14)
Implementation Method 2
a Venturi nozzle 9, which is arranged in the full-load venting path 14 and which generates a necessary differential pressure across the full-load venting path in the case of boost pressures above ambient level
Data Source
AI summary
A method and a device for pressure sensor diagnosis in a tank venting system of a motor vehicle operated by an internal combustion engine is disclosed. The tank venting system includes an activated carbon filter, a purge line arranged between the activated carbon filter, and an intake tract of the motor vehicle. A tank venting valve is arranged in the purge line and a pressure sensor is arranged in the purge line. The method includes measuring a pressure prevailing in the purge line by way of the pressure sensor to determine a starting pressure, classifying the starting pressure into one of a plurality of pressure ranges depending on the amplitude of the starting pressure, and carrying out a pressure sensor diagnosis using a diagnosis algorithm which is associated with the pressure range in which the starting pressure lies.