Crankcase Vent Tube Pressure Sensor Air Filter Plugging Detection
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Solution Overview
Problem
Existing methods for monitoring air filter plugging in engines, such as using manifold air flow sensors or dedicated pressure sensors, are less desirable due to cost and complexity issues, and may not accurately detect filter degradation.
Innovation Solution
Utilizing an existing pressure sensor in the crankcase vent tube to indicate air filter plugging by learning offsets during low engine air flow conditions and applying them during high engine air flow conditions, thereby reducing the need for additional sensors and maintaining crankcase ventilation system activity during diagnostics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated pressure sensors are positioned downstream of the air filter to detect pressure depression, then air filter plugging detection accuracy is improved, but system cost and complexity increase substantially
Solution Approach 1:
The crankcase vent tube pressure sensor, originally designed for crankcase ventilation monitoring, is made multi-functional by using it to detect air filter plugging conditions. The controller performs offset learning during cranking and applies it during operation to determine filter plugging, eliminating the need for a dedicated sensor and reducing system complexity while maintaining detection accuracy
Solution Approach 2:
The existing pressure sensor system serves itself by using the crankcase vent tube pressure data for dual purposes: monitoring crankcase ventilation and detecting air filter plugging. The controller leverages the same sensor infrastructure to perform both functions, avoiding additional hardware costs
2Measurement precision
If manifold air flow sensors are used to detect changes in air flow resulting from filter plugging, then air filter plugging detection is enabled, but MAF sensor data is less desirable than speed density data making MAF sensors less available
Solution Approach 1:
The crankcase vent tube pressure acts as an intermediary parameter that indirectly reflects air filter plugging conditions. Instead of directly measuring manifold air flow with a MAF sensor, the system uses pressure changes in the vent tube as a mediator to infer filter status, bypassing the need for MAF sensor data while maintaining detection capability
Solution Approach 2:
The system replaces the mechanical/electronic MAF sensor measurement approach with a pressure-based detection method using the existing crankcase vent tube pressure sensor. This substitution eliminates dependency on MAF sensor availability while providing reliable plugging detection
3Measurement precision
If additional sensors and valves are added to monitor air filter degradation, then detection accuracy is improved, but cost and complexity increase
Solution Approach 1:
The crankcase vent tube pressure sensor is made multi-functional to monitor both crankcase ventilation and air filter plugging conditions. By leveraging the existing sensor for dual purposes with appropriate offset learning and pressure differential analysis, the system achieves accurate degradation detection without adding new sensors or valves
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 accurately and reliably detects air filter plugging without increasing complexity or cost, while reducing reliance on MAF sensor data and maintaining system integrity.
Implementation Method 1
a pressure sensor positioned within the crankcase vent tube for providing an estimate of flow or pressure of air flowing through the vent tube
Implementation Method 2
a crankcase vent tube coupled between an air intake passage and a crankcase
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.