Fuel Tank Ventilation Diagnostic via Pressure Segmentation
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Solution Overview
Problem
Current fuel tank ventilation systems for internal combustion engines lack comprehensive diagnostic capabilities to detect errors in multiple discharge pathways, which can lead to harmful emissions and inefficient operation.
Innovation Solution
A diagnostic procedure that assesses pressure differences and changes in the fuel tank system pressure to identify errors in at least two ventilation pathways, using existing sensors and without additional hardware, and provides error signals for control unit intervention, allowing for reliable prevention of emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If comprehensive diagnostic capabilities are added to detect errors in multiple discharge pathways, then emissions control reliability is improved, but device complexity increases
Solution Approach 1:
The diagnostic procedure segments the fuel tank ventilation system into multiple discharge pathways (first and second pathways) and implements separate partial diagnoses for each pathway. This allows comprehensive monitoring of each pathway's functionality independently, improving emissions control reliability without requiring a single complex diagnostic system.
Solution Approach 2:
The system uses existing pressure sensors and control units already present in the fuel tank ventilation system to perform self-diagnosis. The control unit evaluates pressure measurements and generates error signals automatically, eliminating the need for additional diagnostic hardware while maintaining high reliability.
2Measurement precision
If pressure measurements are taken in multiple discharge areas to diagnose ventilation pathways, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The existing pressure sensor in the fuel tank system serves multiple functions: it monitors fuel tank pressure during normal operation and provides pressure data for diagnostic evaluation of both ventilation pathways. The control unit multiplies the utility of this single sensor by implementing different diagnostic interpretations based on pressure measurements, achieving precise multi-point diagnosis without additional sensors.
3Measurement precision
If partial diagnoses are implemented for each ventilation pathway based on pressure differences, then diagnostic accuracy is improved, but loss of time increases
Solution Approach 1:
The diagnostic procedure operates continuously by constantly monitoring pressure measurements in the fuel tank system and immediately evaluating them against diagnostic criteria. The control unit continuously assesses pressure differences to determine pathway functionality, eliminating the need for separate diagnostic cycles and providing real-time accuracy without time loss.
Solution Approach 2:
The system performs preliminary evaluation of pressure measurements against diagnostic thresholds before formal error determination. The control unit continuously compares pressure data with expected ranges and prepares diagnostic conclusions in advance, enabling rapid and accurate pathway assessment without time-consuming analysis delays.
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 a complete diagnosis of fuel tank ventilation systems with multiple discharge points, reducing harmful emissions by identifying and addressing errors in ventilation pathways, thereby ensuring reliable operation and emissions control.
Implementation Method 1
assess a measurement for the pressure and/or the pressure change in the fuel tank system
Data Source
AI summary
A procedure to diagnose a fuel tank ventilation system of a motor vehicle and a device to implement the procedure are proposed. The fuel tank ventilation system contains at least one first ventilation pathway discharging into the air intake area of the internal combustion engine downstream behind a supercharger as well as at least one second ventilation pathway discharging into the air intake area upstream in front of the supercharger. Provision is made for a diagnosis with at least two partial diagnoses, whereby the first partial diagnosis pertaining to the first ventilation pathway is implemented, if the intake manifold pressure in the discharge area of the first ventilation pathway is smaller than the fuel tank system pressure; and the second partial diagnosis pertaining to the second ventilation pathway is implemented, if the intake manifold pressure in the discharge area of the first ventilation pathway is greater than the fuel tank system pressure. An error signal is provided, if at least one of the partial diagnoses generates a partial error signal.