Closed Crankcase Ventilation Leak Detection Using One Pressure Sensor
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Solution Overview
Problem
Existing closed crankcase ventilation (CCV) systems lack reliable and accurate diagnostic methods to detect small leaks and defects, which are critical for maintaining low emissions from internal combustion engines.
Innovation Solution
A diagnostic system using a single pressure sensor in the blow-by line to measure pressure relative to atmospheric pressure, calculating delta pressure and average pressure over a defined time period, and comparing these values to calibrated thresholds to detect leaks, with optional dual pressure sensors for additional sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If traditional open crankcase ventilation systems are used, then the system structure is simple, but emissions are high as blow-by gases are released into the atmosphere
Solution Approach 1:
The patent converts the harmful blow-by gases that would normally be vented to atmosphere into a useful resource by routing them through the air intake system for recirculation and combustion, thereby reducing emissions while maintaining system feasibility
Solution Approach 2:
The patent introduces an intermediary closed crankcase ventilation system with blow-by line, pressure sensor, and control unit that mediates between the crankcase and atmosphere, allowing monitoring and controlled recirculation of blow-by gases rather than direct release
2Reliability
If closed crankcase ventilation systems are used, then emissions are reduced by recirculating blow-by gases, but diagnostic reliability is insufficient to detect small leaks
Solution Approach 1:
The patent replaces complex mechanical diagnostic methods with an electronic pressure sensing and evaluation system that can detect small pressure changes indicating leaks, thereby improving measurement precision without excessive complexity
Solution Approach 2:
The patent enables the CCV system to self-diagnose by continuously monitoring pressure through the pressure sensor and automatically evaluating leak conditions through the control unit, providing ongoing reliability verification without external intervention
3Measurement precision
If multiple pressure sensors are used to improve leak detection accuracy, then measurement precision increases, but device complexity increases
Solution Approach 1:
The patent places the pressure sensor at a specific strategic location in the blow-by line where pressure changes most accurately indicate leaks, thereby achieving high detection precision with a single sensor rather than requiring multiple sensors throughout the system
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
Enhances the sensitivity and accuracy of leak detection without increasing sensor complexity, ensuring timely maintenance and reducing emissions by accurately identifying defects and leaks in the CCV system.
Implementation Method 1
When the internal combustion engine is running, the air intake line provides a vacuum source for drawing blow-by gases from the crankcase through the blow-by line
Implementation Method 2
One or more pressure sensors of the system are each arranged for measuring a pressure in the blow-by line relative to atmospheric pressure
Data Source
AI summary
A closed crankcase ventilation system for removing blow-by gases, leaking from a combustion chamber, from a crankcase of an internal combustion engine. The system comprises a blow-by line extending between the crankcase and an air intake line of the internal combustion engine. When the engine is running, the air intake line provides a vacuum source for drawing blow-by gases from the crankcase through the blow-by line. A crankcase depression regulator is arranged in the blow-by line for regulating a level of vacuum inside the crankcase. At least one pressure sensor is arranged for measuring a pressure in the blow-by line relative to atmospheric pressure. A control unit is arranged for detecting leakages in the blow-by line by performing a diagnostic test based on a pressure measurement signal from a single pressure sensor.