PCV Valve Vent Window for Crankcase Disconnection Detection
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Solution Overview
Problem
Current PCV valves are unable to reliably detect when they become dislodged from the crankcase, leading to unregulated emissions of non-combusted gases into the atmosphere, as existing sensors cannot distinguish between secure and dislodged states due to similar air flow restrictions, making it difficult to comply with tightening emissions standards.
Innovation Solution
A PCV valve design featuring a tubular body with a metering device and strategically positioned windows that increase the air flow path area when disconnected, allowing for detectable excessive gas flow beyond normal operating conditions, enabling sensors to flag disconnection issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the PCV valve uses a restricted flow path through the pintle assembly, then the gas flow is controlled during normal operation, but the dislodged condition becomes undetectable by mass flow sensors
Solution Approach 1:
The flow path is segmented into two distinct pathways: a restricted path through the pintle assembly for normal operation, and an unrestricted path through the window in the tubular body for detection. This segmentation allows the system to differentiate between normal and dislodged states by comparing flow through different pathways.
Solution Approach 2:
The window acts as an intermediary detection mechanism. When the PCV valve is dislodged, atmospheric pressure opens the window, allowing unrestricted air flow that serves as a detectable signal. The window mediates between the dislodged state and the sensor detection system.
2Ease of operation
If the PCV valve allows some gas flow during normal operation, then the ventilation function is maintained, but the dislodged condition cannot be distinguished from normal operation
Solution Approach 1:
Different parts of the PCV valve have different flow characteristics: the pintle assembly provides restricted flow with specific metering qualities for normal operation, while the window provides unrestricted flow when opened. This local quality difference enables precise detection of disconnection conditions.
Solution Approach 2:
The window is designed to remain closed during normal operation, allowing only the necessary restricted flow through the pintle. When dislodged, it opens to allow excessive air flow that exceeds normal operational requirements, providing a clear detection signal.
3Ease of manufacture
If the PCV valve is designed with a simple structure, then the manufacturing cost is reduced, but the ability to detect disconnection is compromised
Solution Approach 1:
The detection function is merged into the existing PCV valve structure by incorporating the window directly into the tubular body. This combining of detection and ventilation functions eliminates the need for separate detection mechanisms, maintaining manufacturing simplicity while enabling disconnection detection.
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
The enhanced PCV valve design allows for reliable detection of disconnection from the crankcase, preventing unregulated emissions by ensuring that excessive gas flow is detectable, thus meeting stricter emissions standards and preventing environmental pollution.
Implementation Method 1
During operation of the engine, there is not a high vacuum in the air intake, and a pressure differential is formed on either side of the pintle, causing movement of the pintle and resulting in gas flow from the crankcase to the intake manifold.
Data Source
AI summary
A positive crankcase ventilation (PCV) valve includes a tubular body extending along an axis between a first end and a second end, the tubular body having an outer diameter and an inner diameter defining a wall around a central passage that extends through the tubular body and is orthogonal to the axis, and a metering device secured within the central passage adjacent the first end. The wall includes a window between the metering device and second end, and the window defines an air flow path through the wall and into the central passage for detecting a disconnection of the PCV valve from the crankcase, wherein a total area of the window is greater than an open axial area within the metering device when the metering device is in a maximum flow condition.