Oil Mist Separator Valve Using Float and Pressure Control

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Solution Overview

Problem

Existing oil mist separators for internal combustion engines face issues with unreliable operation under unfavorable pressure conditions and require excessive assembly effort due to separate lines for oil and condensate return, leading to potential oil entry into the raw gas side and increased complexity.

Innovation Solution

The oil mist separator employs a dual-function valve combining float and check valve functions, using a hollow ball valve body that floats on oil to prevent backflow and opens only under specific pressure conditions, and integrates the condensate return channel into the oil return channel to reduce parts and assembly complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate condensate return channel is provided from the raw gas channel to the crankcase, then condensate can be returned to the crankcase, but the number of separate lines increases requiring more assembly effort

Engineering Contradiction:
Improvecondensate return functionVSAvoidnumber of separate lines
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the condensate return channel with the oil return channel by providing a common return channel that receives both condensate from the raw gas channel and oil from the separator. This consolidation reduces the number of separate lines from two (oil return and condensate return) to one (common return channel), thereby reducing assembly effort while maintaining both condensate return and oil return functions

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The common return channel serves multiple functions: it acts as both the oil return channel and the condensate return channel. The channel is designed with a valve that can handle both oil and condensate flow, making it a universal return path that eliminates the need for separate dedicated channels for each fluid type

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a check valve is arranged in the oil return channel to prevent gas flow, then gas backflow is prevented, but oil can still rise into the separator under unfavorable pressure conditions

Engineering Contradiction:
Improvegas flow controlVSAvoidoil entry into separator
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a floating ball valve as an intermediary mechanism in the oil return channel. This valve uses a floating ball that responds to both gas pressure differences and oil level changes. The ball floats on oil to detect oil presence and closes the channel when oil rises, while also responding to gas pressure gradients. This intermediary mechanism simultaneously prevents both gas backflow and oil intrusion into the separator

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The valve mechanism utilizes changes in physical parameters: the floating ball's position changes in response to oil level (buoyancy) and gas pressure differential. When gas pressure exceeds oil pressure, the ball moves to open the channel; when oil level rises or pressure differential reverses, the ball moves to close the channel. This parameter-based control enables simultaneous prevention of gas and oil backflow

Inventive Principle:
Principle #35Parameter changes

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 design ensures reliable operation under adverse pressure conditions, reduces assembly effort, and complies with emission limits by preventing oil and condensate backflow while using a single valve for both functions, thus enhancing operational reliability and simplifying installation.

Implementation Method 1

the valve has a floating body as the valve body, the density of which is smaller than the density of oil and which is due to an oil level in the oil return channel rising from the crankcase Closed position can be raised against a valve seat

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

the weight of the valve body and the dimensions of a valve channel surrounding the valve body are coordinated with one another in such a way that when a predetermined speed of a gas flow in the valve channel is reached in the direction from the crankcase to the separator housing, the valve body is passed through the gas flow and a The gas pressure difference acting on the valve body can be raised into its closed position against the valve seat

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Data Source

PatentEP2558690B1Oil mist separator of a crankcase ventilation device of an internal combustion engine
Publication Date: 2015.10.28 HENGST WALTER
  • EP2558690B1 patent drawingFigure 1
  • EP2558690B1 patent drawingFigure 2
  • EP2558690B1 patent drawingFigure 3

AI summary

The invention relates to an oil mist separator (1) of a crankcase ventilation device of an internal combustion engine, comprising a separator housing (10), a raw gas channel (12) conducting raw gas out of the crankcase of the internal combustion engine into a raw gas region (11.1) of the separator (1), a clean gas channel discharging clean gas from the clean gas region (11.2) of the separator (1), and an oil recirculation channel (14) recirculating oil separated from the crankcase ventilation gas into the crankcase of the internal combustion engine. A valve (2) which opens the oil recirculation channel (14) if a predeterminable pressure difference between the two sides of the valve (2) is no longer met is arranged in the course of said oil recirculation channel. The oil mist separator (1) according to the invention is characterized in that the valve (2) has a float element as a valve body (20), the density of said float element being lower than the density of oil. Said float element can be raised in the closed position thereof against a valve seat (21) by an oil level in the oil recirculation channel (14) that rises starting from the crankcase. The weight of the valve body (20) and the size of a valve channel (22) enclosing the valve body (20) are matched to each other such that, when a predeterminable velocity of a gas flow is reached in the valve channel (22) in the direction from the crankcase to the separator housing (10), the valve body (20) can be raised against the valve seat (21) into the closed position by the gas flow and a gas pressure difference acting on the valve body (20).