Crankcase Ventilation Flow Control for Passive Leak Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing crankcase ventilation systems in automotive engines require expensive and space-consuming solenoid-powered gate valves for pressure integrity checks, which also necessitate electrical connections for operation.
Innovation Solution
A flow control device with a tuned orifice and two check valves in a parallel configuration, allowing for constant restriction in the normal flow direction and free flow in the opposite direction without the need for electrical connections.
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 requires electrical connections
Solution Approach 1:
The flow control device uses passive mechanical check valves that automatically open or close based on pressure differential, eliminating the need for external electrical actuation. The device serves itself by using the engine's own operating conditions (intake manifold vacuum) to control the check valves for pressure integrity testing.
Solution Approach 2:
The patent replaces the electrical solenoid actuation system with a purely mechanical flow control device using check valves and restrictors. This mechanical substitution eliminates electrical connections while maintaining the ability to perform pressure integrity checks through passive mechanical means.
2Reliability
If a solenoid-powered gate valve is used for pressure integrity checks, then the crankcase ventilation system can detect leaks, but the system takes up more engine space
Solution Approach 1:
The flow control device combines multiple functions (pressure integrity testing, normal crankcase ventilation, and check valve control) into a single integrated assembly. This merging of functions reduces the overall space required compared to separate solenoid valve and ventilation system components.
Solution Approach 2:
The check valves and restrictors are nested within a compact housing that integrates with the existing crankcase ventilation system. The passive mechanical components are arranged in a space-efficient configuration that eliminates the need for additional external actuator mounting space.
3Reliability
If a gate valve with rigid gate is used to stop flow, then pressure integrity check can be conducted, but the system is more expensive
Solution Approach 1:
The patent uses simple, inexpensive passive mechanical components (check valves, restrictors, and housing) instead of expensive solenoid-powered gate valves. These basic mechanical parts are more cost-effective to manufacture while still achieving the required pressure integrity testing functionality.
Solution Approach 2:
The flow control device requires no external power source or complex control systems, using only passive mechanical elements that rely on pressure differentials to function. This self-service approach eliminates the need for expensive electrical actuators and control electronics.
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 system enables efficient pressure integrity checks of the crankcase ventilation system while being more cost-effective and compact, eliminating the need for electrical actuation and reducing potential leak points.
Implementation Method 1
The pressure in an engine crankcase is ideally maintained near atmospheric pressure (ATM pressure +/- 5 kPa). Furthermore, it is desirable to be able to detect any leak in the crankcase ventilation system
Implementation Method 2
A flow control device with a tuned orifice and two check valves in a parallel configuration, allowing for constant restriction in the normal flow direction and free flow in the opposite direction
Data Source
Figure 1
Figure 2
Figure 3
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.