Gravity-Actuated Check Valve for Crankcase Oil Return
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Solution Overview
Problem
Existing non-return valves for oil return in internal combustion engine crankcase ventilation often freeze during idle due to inadequate drainage, and their installation and removal can be cumbersome, requiring additional components and high effort.
Innovation Solution
A non-return valve integrated into the cylinder head cover, with a gravity-actuated valve body that opens without preload, allowing for easy installation and removal, and features a latching mechanism to prevent unintended closure, ensuring maximum opening cross-section for drainage and preventing oil-laden gas penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a siphon is arranged in the oil return to prevent oil from entering the crankcase, then oil sealing is improved, but the risk of freezing increases due to oil present in the siphon
Solution Approach 1:
The patent removes the siphon structure from the oil return system and replaces it with a check valve integrated into the cylinder head cover. This extracts the harmful element (siphon containing oil that can freeze) while maintaining the oil return function through a different mechanism that doesn't retain oil in the return path.
Solution Approach 2:
The check valve acts as an intermediary component between the crankcase and oil separator chamber. It mediates the oil return flow by allowing controlled passage while preventing backflow, replacing the siphon's function without retaining oil in the return line.
2Productivity
If a spring tongue valve is used to control oil return, then oil flow control is improved, but the valve is in closed position at rest causing freezing risk
Solution Approach 1:
The patent inverts the default position logic of conventional check valves. Instead of being closed at rest and opening under pressure, this valve is open at rest due to gravity and closes when pressure differential exceeds gravitational force. This inversion ensures maximum drainage at idle while maintaining sealing under pressure.
Solution Approach 2:
The valve body uses gravity as a counterbalancing force against pressure differential. The gravitational force on the valve body keeps it open during idle, counteracting the pressure that would otherwise keep it closed, enabling drainage without freezing risk.
3Reliability
If a check valve is inserted into the crankcase receptacle, then oil return function is improved, but installation complexity and removal effort increase
Solution Approach 1:
The check valve is merged with the cylinder head cover as an integrated assembly. The valve housing forms part of the cylinder head cover structure, eliminating the need for separate installation into the crankcase receptacle. This combining simplifies both installation and removal procedures.
Solution Approach 2:
The cylinder head cover serves multiple functions: it houses the engine components, provides the oil return pathway, and contains the check valve mechanism. This multi-functionality eliminates the need for separate check valve installation, simplifying the overall system.
4Productivity
If the valve body is held in open position without prestress, then drainage capability is improved, but valve stability may be compromised
Solution Approach 1:
The patent inverts the prestress concept: instead of applying prestress to keep the valve open, it uses gravity as the natural holding force. The valve body's weight provides the stabilizing force that maintains the open position during idle, eliminating the need for springs or other prestressing mechanisms.
Solution Approach 2:
The valve body uses its own weight as the stabilizing force. This self-service approach eliminates the need for external springs, prestressing elements, or complex stabilization mechanisms, while maintaining reliable open position during drainage operations.
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 effectively prevents oil from entering the clean room, reduces the risk of freezing, and simplifies the installation and removal process by eliminating the need for additional components and external energy sources.
Implementation Method 1
the valve body being held in the open position free of prestress when the internal combustion engine is at rest
Implementation Method 2
an overpressure on the crankcase side relative to the oil separator chamber for automatic shifting into the closed position
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A check valve (20) for oil return in the crankcase ventilation of an internal combustion engine comprises a valve housing (27) and a valve body (37) which is slidably held as a whole within the valve housing (27) between an open position and a closed position. In the rest state of the internal combustion engine, the valve body (37) is held in the open position without preload, and the valve body (37) is designed to move automatically into the closed position due to overpressure on the crankcase side (16) relative to the oil separator chamber (22). The check valve (20) is designed and configured for insertion into a receptacle (15) in a cylinder head cover (10) of the internal combustion engine.