Crankcase Vent Tube Pressure Sensor Breach Detection
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Solution Overview
Problem
Existing crankcase ventilation system monitoring methods are costly and complex, with additional sensors and valves increasing redundancy without improving accuracy, and fail to accurately discern the location and nature of breaches, such as a disconnected breather tube or an open oil cap.
Innovation Solution
A method that uses a pressure sensor in the crankcase vent tube to detect transient pressure dips during cranking and changes in vent tube pressure during steady-state airflow to infer breaches, allowing the controller to determine the location and nature of the breach and take appropriate mitigating actions, potentially reducing the number of sensors and valves needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional sensors and valves are added to the monitoring system, then the monitoring capability is improved, but the system complexity and cost increase
Solution Approach 1:
The existing crankcase vent tube pressure sensor is made multi-functional by using it to detect both normal crankcase pressure and transient pressure dips during cranking. This allows the single sensor to perform multiple diagnostic functions, eliminating the need for additional dedicated sensors while maintaining comprehensive monitoring capability
Solution Approach 2:
The system uses its existing pressure sensor to self-diagnose crankcase ventilation breaches by analyzing transient pressure dips during cranking. The system leverages its own operational data and existing hardware to perform monitoring, eliminating the need for separate dedicated monitoring components
2Reliability
If multiple pressure sensors are positioned at different locations, then the monitoring coverage is improved, but the redundancy increases without improving diagnostic accuracy
Solution Approach 1:
The system performs preliminary diagnostic action during engine cranking by detecting transient pressure dips before the engine reaches operating conditions. This early detection phase provides unique diagnostic information that cannot be obtained during normal operation, enabling accurate breach location identification with a single sensor
Solution Approach 2:
The system utilizes dynamic cranking conditions to create transient pressure dips that reveal breach locations. By analyzing the dynamic pressure response during the transient cranking phase rather than static operating conditions, the system achieves precise diagnostic information from a single sensor location
3Reliability
If multiple sensors are used to monitor the system, then the monitoring thoroughness is improved, but the ability to accurately discern breach location remains insufficient
Solution Approach 1:
The system changes the operational parameter by analyzing pressure dips during cranking rather than steady-state operation. This parameter change reveals location-specific diagnostic information that allows the single sensor to distinguish between breaches at different locations (air intake passage side versus crankcase side) based on the characteristics of the transient pressure response
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 approach allows for accurate identification of crankcase ventilation system breaches, reduces hardware and complexity, and keeps the system active during diagnostics, enabling effective mitigating actions to prevent engine component degradation.
Implementation Method 1
a pressure sensor (or flow sensor) positioned within the crankcase vent tube for providing an estimate of flow or pressure of air flowing through the vent tube
Data Source
AI summary
Methods and systems are provided for using a crankcase vent tube pressure or flow sensor for diagnosing a location and nature of crankcase system integrity breach. The same sensor can also be used for diagnosing air filter plugging and PCV valve degradation. Use of an existing sensor to diagnose multiple engine components provides cost reduction and sensor compaction benefits.