Crankcase Ventilation Flow Control for Passive Leak Diagnostics
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Solution Overview
Problem
Current crankcase ventilation systems in automotive engines require expensive and space-consuming solenoid-powered gate valves for pressure integrity checks, which is not cost-effective and lacks a compact solution for detecting leaks without electrical actuation.
Innovation Solution
A flow control device with parallel conduits, including a normally closed check valve, a normally neutral check valve, and a restrictor, which allows for pressure differential-controlled flow in both directions without electrical actuation, utilizing a hemispherical poppet check valve and a flexible sealing disc to detect leaks using a pressure sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solenoid-powered gate valve is used for pressure integrity checks, then the crankcase ventilation system can detect leaks, but the system becomes more expensive and consumes more engine space
Solution Approach 1:
The patent extracts the electrical actuation component (solenoid) from the valve mechanism, leaving only the passive check valve and restrictor elements. This removes the need for electrical connections and complex control systems while retaining the pressure differential-based flow control function for leak detection
Solution Approach 2:
The check valve and restrictor are designed to automatically respond to pressure differentials without external control. The valve opens or closes based on the pressure relationship between crankcase and atmosphere, enabling self-regulating flow control that eliminates the need for solenoid actuation
2Ease of operation
If a gate valve with solenoid actuation is deployed, then flow can be controlled for pressure checks, but the system requires electrical connections and actuator operation
Solution Approach 1:
The patent replaces the electrical-mechanical system (solenoid coil converting electrical energy to mechanical motion) with a purely mechanical pressure-responsive system. The check valve and restrictor use pressure differentials directly to control flow, eliminating electrical components while maintaining flow control functionality
Solution Approach 2:
The system uses pneumatic pressure differentials between the crankcase and atmosphere to directly actuate the check valve and control flow through the restrictor. This pneumatic actuation mechanism replaces electrical actuation, using the existing pressure field in the crankcase ventilation system
3Stress or pressure
If free flow of air into the crankcase is maintained, then crankcase pressure is stabilized near atmospheric pressure, but the system cannot perform pressure integrity checks
Solution Approach 1:
The restrictor provides dynamically adjustable flow resistance based on pressure differentials. During normal operation, the restrictor maintains stable crankcase pressure by allowing free flow when pressure is near atmospheric. During diagnostic modes, the restrictor creates controlled flow restriction enabling pressure integrity checks by comparing expected versus actual pressure differentials
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 solution provides a compact, cost-effective, and efficient means to detect leaks in the crankcase ventilation system, reducing the need for electrical connections and minimizing engine space, while ensuring pressure integrity without creating excessive negative pressure.
Implementation Method 1
a spring biasing the hemispherical poppet sealing member to a closed position
Implementation Method 2
a sealing disc translatable between an open position and a closed position in response solely to a pressure differential in the second conduit
Implementation Method 3
The third conduit defines a restriction profile, i.e., has a restrictor, having a third preselected pressure differential
Data Source
AI summary
Flow control devices herein have a housing defining a plurality of parallel conduits. The first conduit has a normally closed check valve defined to open under a first preselected pressure differential controlling flow through the first conduit in a first direction of flow. The second conduit has a normally neutral check valve defined to open under a second preselected pressure differential in a second direction of flow that is opposite the first direction of flow. The third conduit defines a restriction profile, i.e., has a restrictor, having a third preselected pressure differential. The flow control devices are included as part of an engine system, more specifically a crankcase ventilation breach detection system.