Backflow Valve for Engine Oil Drain Passage
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Solution Overview
Problem
Existing positive crankcase ventilation (PCV) systems face issues with oil backflow into the intake system during certain vehicle maneuvers, leading to increased oil consumption and decreased combustion efficiency due to the oil drain passage not being submerged in oil, causing elevated pressures and oil to travel up the drain passage.
Innovation Solution
Incorporating a backflow valve in the oil drain passage that switches between allowing oil backflow and inhibiting it based on crankcase pressure, using an oil level stick to indicate oil levels and prevent backflow during high pressures, ensuring oil is only drained during low pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the oil drain passage outlet is not submerged in oil during certain operating conditions, then the PCV system can vent crankcase gases effectively, but oil backflow occurs into the intake system increasing oil consumption
Solution Approach 1:
The backflow valve dynamically changes its state between open and closed positions based on crankcase pressure conditions. During normal operation, the valve remains open to allow oil drainage. When elevated pressure is detected (indicating oil level submersion), the valve closes to prevent oil backflow into the intake system, thus adapting to changing operating conditions
Solution Approach 2:
The system monitors crankcase pressure as a parameter to determine valve actuation. When pressure exceeds a predetermined threshold, the backflow valve switches from open to closed state, using pressure parameter changes to control oil flow and prevent backflow
2Reliability
If the backflow valve inhibits oil backflow during high pressure, then combustion efficiency increases, but oil level indication capability is lost
Solution Approach 1:
The oil drain passage is segmented into two functional zones: the lower portion serves as both drainage path and oil level indication medium, while the upper portion contains the backflow valve mechanism. This segmentation allows the lower section to provide oil level information to the float indicator while the upper section controls backflow prevention
Solution Approach 2:
The oil drain passage serves multiple functions simultaneously: it drains oil from the crankcase, provides oil level indication through the float mechanism, and (when the backflow valve is closed) prevents oil backflow into the intake system. This multi-functionality resolves the contradiction between indication and backflow prevention
3Measurement precision
If an oil level stick extends down the oil drain passage for indication, then oil level can be monitored, but the passage cannot be fully submerged in oil
Solution Approach 1:
The backflow valve acts as an intermediary component between the oil drain passage and the intake system. It allows the oil level stick to extend into the drain passage for accurate indication while preventing oil from flowing back into the intake system when the valve closes during high pressure conditions
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
This solution effectively prevents oil backflow into the intake system during high-pressure conditions, reducing oil consumption and enhancing combustion efficiency by allowing controlled oil drainage and level indication during low-pressure conditions.
Implementation Method 1
The first configuration may be initiated when a pressure in the crankcase is below a threshold value and the second configuration may be initiated when the pressure is above the threshold value
Data Source
AI summary
An engine system is described. The engine system includes an oil drain passage in fluidic communication with an oil separator. The engine system further includes a backflow valve positioned at an outlet of the oil drain line, the backflow valve having a first configuration where the valve provides a predetermined amount of oil backflow into the oil drain passage and a second configuration where the valve inhibits oil backflow into the oil drain passage.