Filter System Non-Return Valve Oil Retention

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Solution Overview

Problem

Existing oil filter systems for internal combustion engines do not effectively prevent oil level drops when oil pressure is low or the engine is shut off, and they are not designed for easy and complete drainage during maintenance.

Innovation Solution

A filter system with a check valve integrated into the outlet port, where the check valve closes the fluid path during low pressure or engine shutdown, and opens it as pressure builds up, allowing for efficient oil retention and quick lubrication upon restart, while also allowing for complete drainage during filter element replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional filter system without check valve is used, then the structure is simple and cost-effective, but oil level drops occur when oil pressure is low or engine is shut off

Engineering Contradiction:
Improveoil level stabilityVSAvoidfilter system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The check valve is extracted as a separate functional component from the filter element assembly. It is installed independently in the outlet nozzle, allowing the filter element to remain simple and replaceable while adding the oil retention function through the separate check valve mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The check valve acts as an intermediary component between the filter element and the outlet nozzle. It mediates the fluid flow by automatically opening during normal operation and closing during low pressure or shutdown conditions, preventing direct backflow that would cause oil level drops.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the check valve is integrated into the filter element, then oil retention is improved, but the filter element becomes more complex and difficult to replace

Engineering Contradiction:
Improveoil retention capabilityVSAvoidfilter element assembly
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The check valve is extracted from the filter element structure and installed separately in the outlet nozzle. This allows the filter element to remain a simple, replaceable component while the check valve provides the oil retention function independently, simplifying both manufacturing and maintenance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The filter system is segmented into distinct functional components: the filter element for filtration and the check valve for oil retention. This segmentation allows each component to be optimized independently and facilitates easy replacement of the filter element without affecting the check valve functionality.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the check valve remains closed during filter element replacement, then oil retention is maintained, but complete drainage for maintenance is prevented

Engineering Contradiction:
Improveoil retentionVSAvoidoil drainage during maintenance
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system is designed so that during normal operation the check valve is closed to retain oil, but during maintenance the filter element removal creates a pressure differential that automatically opens the check valve for complete drainage. The preliminary closing action during operation enables the subsequent draining action during maintenance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The check valve transitions dynamically between closed and open states based on operating conditions. During normal operation it remains closed for oil retention, but during filter element replacement the pressure change causes it to open automatically, enabling complete drainage without manual intervention.

Inventive Principle:
Principle #15Dynamics

4Speed

If the check valve opens immediately upon pressure build-up, then rapid lubrication is achieved, but oil level stability at low pressure is compromised

Engineering Contradiction:
Improveoil pressure recovery speedVSAvoidoil level stability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The check valve is designed to respond to pressure parameter changes by transitioning from closed to open state. It remains closed at low pressure to maintain oil level stability, and automatically opens when sufficient pressure builds up to enable rapid oil flow and lubrication recovery.

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

The check valve system prevents oil level drops and ensures rapid oil pressure recovery upon engine restart, while enabling efficient oil drainage and replacement during maintenance, optimizing oil retention and lubrication functions.

Implementation Method 1

a closure element supported against a valve seat by a spring element

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

the check valve closes a fluid path through the outlet nozzle in a closed position and opens the fluid path through the outlet nozzle in an open position

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 3

a filter element which separates a raw fluid side from a clean fluid side

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentEP3727641B1Filter system with non-return valve and filter element
Publication Date: 2024.01.03 MANN HUMMEL GMBH
  • EP3727641B1 patent drawingFigure 1
  • EP3727641B1 patent drawingFigure 2
  • EP3727641B1 patent drawingFigure 3

AI summary

The invention relates to a filter system (100) for filtering a fluid, comprising a filter housing (110) with a housing upper part (114) and a housing lower part (112), which extend along a housing axis (M), an outlet connection piece (108) arranged on the housing upper part (114) for discharging the filtered fluid, a non-return valve (30), which is arranged inside the connection piece (108), and a filter element (10), which separates an untreated fluid side (50) from a clean fluid side (52). The filter element (10) comprises a valve seat (34) for the non-return valve (30). The non-return valve (30) in a closed position (P1) closes a fluid path (56) through the outlet connection piece (108) and in an open position (P2) releases the fluid path (56) through the outlet connection (108). The invention also relates to a non-return valve (30) and a filter element (10).