Dual Purge System Failure Diagnosis via Pressure Measurement
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Solution Overview
Problem
Conventional failure diagnosis methods for dual purge systems struggle to accurately diagnose issues in the boosting region, particularly due to the influence of external conditions and added components, making it difficult to determine abnormalities within the purge system independently.
Innovation Solution
A dual purge system failure diagnosis method involving a primary purge line, secondary purge line, and recirculation line, with a controller measuring pressure at the negative pressure formation device in open and closed states, comparing it to reference values to diagnose stuck failures in the system, and a pressure sensor unit to detect anomalies, allowing for precise identification of failure locations and types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dual purge system with additional components (negative pressure formation device, negative pressure line, recirculation line) is added to the conventional single purge system, then the purge function in the boosting region is improved, but the device complexity increases and the difficulty of detecting and measuring failures increases
Solution Approach 1:
The patent segments the dual purge system into distinct functional zones: the primary purge line connected to the supercharging line, the secondary purge line connected to the negative pressure formation device, and the recirculation line. By segmenting the system and assigning specific diagnostic procedures to each segment, the complexity of diagnosing the entire system is reduced while maintaining the enhanced purge functionality.
Solution Approach 2:
The patent introduces a recirculation line as an intermediary component that connects the rear end portion of the turbocharger to the negative pressure formation device. This intermediary element enables the negative pressure formation device to receive recirculated air and generate negative pressure effectively, while also providing a dedicated path for diagnostic measurement that isolates the negative pressure formation device's performance from other system variables.
2Ease of manufacture
If fuel tank pressure is used for diagnosing failure in the purge system, then the diagnosis can be performed using existing sensors, but the diagnosis result is affected by external conditions (fuel evaporation pressure, canister close valve operation) making it difficult to determine abnormality in only the purge system
Solution Approach 1:
The patent extracts the diagnostic measurement from the fuel tank pressure (which is influenced by multiple factors) and relocates it to the negative pressure formation device's inlet or outlet. This extraction isolates the measurement from external conditions such as fuel evaporation pressure and canister close valve operation, allowing for precise diagnosis of the purge system's specific components without interference from other system variables.
Solution Approach 2:
The patent implements a feedback mechanism where the controller measures the pressure at the negative pressure formation device and compares it against expected pressure ranges. This feedback loop provides real-time diagnostic information about the status of the negative pressure line and recirculation line, enabling continuous monitoring and precise identification of failures while accounting for the dynamic operation of the dual purge system.
3Reliability
If the conventional OBD regulation diagnosis method is applied to the dual purge system, then the purge to engine impossibility can be monitored, but the failure in the added components (negative pressure formation device, negative pressure line, recirculation line) cannot be specifically diagnosed
Solution Approach 1:
The patent performs preliminary diagnostic actions by measuring the pressure at the negative pressure formation device before determining system failure. This preliminary measurement allows the controller to identify abnormalities in the negative pressure line and recirculation line early, before they cause complete purge failure. The diagnostic procedure is executed in advance to detect component failures while the system is still operational.
Solution Approach 2:
The patent adds another dimension to the diagnostic approach by introducing pressure measurement at the negative pressure formation device, which is a new measurement point not present in conventional single purge systems. This additional measurement dimension enables the controller to distinguish between failures in the primary purge line versus failures in the added components (negative pressure line, recirculation line, negative pressure formation device), providing specific component-level diagnostics.
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 effective diagnosis of dual purge system failures in the boosting region, reducing misdiagnosis and identifying specific failure points, thereby facilitating quicker and cost-effective repairs by isolating issues within the purge system, independent of external conditions.
Implementation Method 1
a negative pressure formation device provided in an air charge line on an upstream of a turbocharger, and having the purge gas flowing due to a forced negative pressure formed by the negative pressure formation device upon boosting the turbocharger
Data Source
AI summary
A failure diagnosis method and a failure diagnosis system of a dual purge system may determine whether a closed stuck failure or an opened stuck failure occurs in a line forming a dual purge system by measuring a pressure in a negative pressure formation device and comparing the corresponding pressure with a predetermined reference value when a purge valve of the dual purge system is in an opened or closed state, and may determine whether the failure occurs in components related to a secondary purge line in the dual purge system in which it is difficult to determine whether the failure occurs in a conventional failure diagnosis method of a single purge system in a simple method.