Integrated Oil Separator in Head Cover for Compact Engine Design

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Solution Overview

Problem

Existing blow-by gas recirculation devices in industrial engines face challenges of increased engine size due to external oil separators and a higher risk of moisture freezing in long external pipes, especially in cold weather.

Innovation Solution

The solution involves integrating the oil separator into the head cover of the engine, thereby eliminating the need for an external oil separator and shortening the external pipe length for blow-by gas, which reduces the risk of freezing and minimizes engine size increase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If an oil separator is disposed outside the head cover as a dedicated part, then the oil separator can have a sufficient capacity, but the size of the entire engine increases

Engineering Contradiction:
Improveoil separator capacityVSAvoidengine size
Core Design Contradiction:
Quantity of substanceVSVolume of stationary object

Solution Approach 1:

The oil separator is integrated into the head cover as a unified structure. The head cover serves dual functions: housing the valve mechanism and containing the oil separator, thereby eliminating the need for a separate external oil separator and reducing overall engine size.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The oil separator is positioned inside the head cover, utilizing the internal space of the head cover. This nested arrangement allows the oil separator to be housed within the existing structure without requiring additional external space, thus maintaining sufficient separation capacity while minimizing engine size increase.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of operation

If an external pipe for blow-by gas is made long to connect head cover and oil separator, then the oil separator can be positioned outside, but the risk of moisture freezing increases in cold weather

Engineering Contradiction:
Improveoil separator accessibilityVSAvoidfreezing risk
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

By integrating the oil separator into the head cover, the patent eliminates the external pipe connection between the head cover and oil separator. The blow-by gas flows directly from the valve mechanism through the integrated oil separator without requiring external piping, thereby eliminating the freezing risk associated with long external pipes.

Inventive Principle:
Principle #5Merging (Combining)

3Volume of stationary object

If an oil separator is integrated into the head cover, then engine size is reduced and external pipe length is shortened, but space for disposing the separator and pressure regulating valve becomes limited

Engineering Contradiction:
Improveengine sizeVSAvoidavailable space in head cover
Core Design Contradiction:
Volume of stationary objectVSArea of stationary object

Solution Approach 1:

The oil separator is arranged in the vertical direction within the head cover, overlapping with the blow-by gas passage and pressure regulating valve in the vertical dimension. This vertical stacking arrangement allows multiple components to coexist within the limited horizontal footprint of the head cover, effectively utilizing three-dimensional space to accommodate all necessary components.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The oil separator is positioned to overlap with the blow-by gas passage and pressure regulating valve, with the separator outlet overlapping the valve inlet. This nested spatial arrangement allows components to be interlocked vertically, maximizing space utilization within the head cover while maintaining all necessary functional connections.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 configuration results in a more compact engine design and significantly reduces the risk of moisture freezing in the blow-by gas recirculation system, enhancing its operational efficiency and reliability, especially in cold conditions.

Implementation Method 1

an oil separator for trapping oil components from the blow-by gas

Methodology Applied
Scientific EffectGravitational settling: Gravitation

Implementation Method 2

an oil separator for trapping oil components from the blow-by gas

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Data Source

PatentEP3985234B1Blow-by gas recirculating device
Publication Date: 2025.05.14 KUBOTA CORP
  • EP3985234B1 patent drawingFigure 1
  • EP3985234B1 patent drawingFigure 2
  • EP3985234B1 patent drawingFigure 3

AI summary

There is provided a blow-by gas recirculation device that, while having a structure in which a passage for blow-by gas is provided in a head cover and an oil separator is also provided, is improved in that an increase in size of an engine is suppressed and the risk of the freezing is avoided as much as possible by shortening the length of an external pipe for the blow-by gas. Therefore, the blow-by gas recirculation device is configured to guide blow-by gas from a crankcase to an intake passage a through an in-cover gas passage 3A formed inside a head cover 3, in which: an oil separator 25 that traps and removes oil from the blow-by gas is attached to the inside of the head cover 3; a pressure regulating valve B is provided on the outlet side of the in-cover gas passage 3A in the head cover 3; and a separator outlet 27, which is an outlet for the blow-by gas in the oil separator 25, is overlapped on a blow-by gas inlet portion 52 of the pressure regulating valve B.