Diagnosing PCV Breather Line Abnormalities Using Crankcase Pressure
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Solution Overview
Problem
Conventional positive crankcase ventilation (PCV) systems face difficulties in diagnosing abnormalities in the breather line due to its complex structure, which cannot be effectively assessed using a MAP sensor.
Innovation Solution
A system and method utilizing a crankcase pressure sensor installed on the PCV breather line to detect pressure and a processor that activates diagnosis modes based on boost pressure, cooling water temperature, barometric pressure, and engine state, calculating accumulated pressure values to determine abnormalities in the breather line connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a MAP sensor is used to diagnose the breather line, then the existing sensor is utilized without additional components, but the complex structure of the breather line prevents accurate diagnosis of abnormalities
Solution Approach 1:
The breather line diagnosis is segmented into two independent parts: rear end diagnosis (cranking state) and front end diagnosis (running state). This segmentation allows each part to be diagnosed using appropriate sensor data and methods, overcoming the limitation of using a single MAP sensor for the entire complex structure.
Solution Approach 2:
A crankcase pressure sensor is introduced as an intermediary device to directly measure pressure in the crankcase. This intermediary sensor provides accurate pressure data that serves as a reliable indicator for breather line abnormalities, bypassing the limitation of indirect measurement by the MAP sensor.
2Ease of operation
If the breather line structure is simplified for easier diagnosis, then diagnosis becomes more straightforward, but the PCV system functionality may be compromised
Solution Approach 1:
The diagnosis system dynamically adapts its operation based on engine state. During cranking state, it performs rear end diagnosis; during running state, it performs front end diagnosis. This dynamic approach enables comprehensive diagnosis of the complex breather line structure without requiring structural simplification, maintaining both ease of operation and system reliability.
Solution Approach 2:
The system performs preliminary checks by monitoring crankcase pressure under specific conditions (cranking and running states) before declaring a fault. This preliminary action under controlled conditions enables accurate diagnosis of the complex PCV system without compromising its functionality.
3Measurement precision
If a crankcase pressure sensor is added to enable accurate diagnosis, then diagnosis precision is improved, but the device complexity and cost increase
Solution Approach 1:
The crankcase pressure sensor serves multiple functions: it enables both rear end diagnosis (during cranking) and front end diagnosis (during running). This multi-functionality justifies the addition of a single sensor, as it provides comprehensive diagnosis capability for the entire breather line system rather than requiring multiple specialized sensors.
Solution Approach 2:
The system utilizes changes in crankcase pressure parameters under different engine states (cranking vs. running) to diagnose different parts of the breather line. By monitoring pressure parameter variations, a single sensor can provide comprehensive diagnosis information, reducing the need for multiple sensors while maintaining high measurement precision.
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 diagnosis of abnormalities in the PCV breather line connections, specifically identifying issues in the rear and front ends by comparing pressure values, thereby improving the reliability of PCV system diagnostics.
Implementation Method 1
a crankcase pressure sensor installed on the PCV breather line... and configured to detect a pressure inside of the crankcase
Data Source
AI summary
A device and a method for diagnosing a positive crankcase ventilation (PCV) breather line. The device includes: a crankcase pressure sensor that is installed on the PCV breather line including a front end connected to an intake line and a rear end connected to a crankcase and detects a pressure inside the crankcase; and a processor that diagnoses an abnormality of the PCV breather line based on the pressure of the crankcase.