Safety Valve with Ventilation for Common Rail Pressure Management

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Solution Overview

Problem

Conventional safety valves for common rail fuel systems in internal combustion engines, particularly in large diesel or heavy fuel oil engines, fail to effectively manage excessive pressure without requiring expensive separate pressure tanks and double-walled connecting pipes, leading to potential damage and increased costs.

Innovation Solution

A safety valve design comprising a housing with a first chamber and a second chamber, where the second chamber has a greater volume and is connected to the first chamber via throttling ports, allowing pressurized fuel to flow and reducing pressure, and includes a ventilation valve to ensure the second chamber is ventilated when the inlet port is sealed, eliminating the need for a separate pressure tank and double-walled pipes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate pressure tank and double-walled connecting pipe are used to discharge pressurized fuel from the common rail, then the high pressure can be safely managed, but the device complexity and cost increase significantly

Engineering Contradiction:
Improvepressure management safetyVSAvoidsystem structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the pressure tank and safety valve into a single integrated unit. The housing contains both the first chamber (safety valve) and second chamber (pressure tank), eliminating the need for separate components and reducing system complexity while maintaining pressure management safety

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a nested structure where the first chamber is positioned within the housing and the second chamber surrounds or contains the first chamber. This nesting arrangement allows the pressure tank to be disposed directly downstream of the safety valve without requiring external connecting pipes, thereby reducing device complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If a separate pressure tank is disposed downstream of the safety valve to collect pressurized fuel, then pressure can be managed, but the need for connecting pipes increases device complexity

Engineering Contradiction:
Improvepressure containmentVSAvoidconnecting components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the pressure tank and safety valve into one integrated device housed within a single housing structure, eliminating the need for external connecting pipes and reducing the number of components that require assembly and maintenance

Inventive Principle:
Principle #5Merging (Combining)

3Stress or pressure

If the second chamber volume is increased to reduce pressure effectively, then pressure drop is improved, but the device size increases

Engineering Contradiction:
Improvepressure reduction efficiencyVSAvoidsafety valve housing volume
Core Design Contradiction:
Stress or pressureVSVolume of stationary object

Solution Approach 1:

The patent uses a nested chamber arrangement where the first chamber is positioned within the housing and the second chamber is configured to surround or contain the first chamber. This nesting allows the second chamber to have a larger volume for effective pressure reduction while maintaining a compact overall device footprint

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent utilizes three-dimensional spatial arrangement of the chambers, where the second chamber extends in multiple directions around the first chamber. This dimensional optimization allows the second chamber to achieve sufficient volume for pressure reduction without proportionally increasing the device's external dimensions

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

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 reduces high pressure within the common rail by allowing pressurized fuel to flow through throttling ports, achieving a significant pressure drop without the need for a separate pressure tank and double-walled pipes, thereby reducing costs and ensuring safe operation of the engine.

Implementation Method 1

a ventilation valve (28) configured to ventilate the second chamber (42) as long as the inlet port (16) is sealed by the closing element (50)

Methodology Applied
Scientific EffectVentilation:

Implementation Method 2

The second chamber (42) may be in flow connection with the first chamber (40) via at least one throttling port (60)

Methodology Applied
Scientific EffectThrottling:

Data Source

PatentEP2233730B1Safety valve with ventilation valve
Publication Date: 2012.03.28 CATERPILLAR MOTOREN GMBH & CO KG
  • EP2233730B1 patent drawingFigure 1
  • EP2233730B1 patent drawingFigure 2
  • EP2233730B1 patent drawingFigure 3~4

AI summary

The present disclosure refers to a safety valve (10; 100) configured to be arranged on a pressurized device such as a common rail (70) of an internal combustion engine. It may comprise a housing (11; 106), a first chamber (40; 132) and a second chamber (42; 188) arranged within said housing (11; 106). Said first chamber (11; 132) may have a first volume and an inlet port (16; 130) configured to provide a flow connection between said common rail (70) and said first chamber (40; 132). A closing element (50; 136) may be arranged to close said inlet port (16; 130) as long as a predetermined pressure within the pressurized device (70) is not exceeded. The second chamber (42; 188) may be in flow connection with the first chamber (40; 132) via at least one throttling bore (60; 190). Said second chamber (42; 188) may have an outlet port (22; 102) configured to drain a fluid within the second chamber (42; 188) out of the second chamber (42; 188). A ventilation valve (28) may be configured to ventilate said second chamber (42) as long as said closing element (50) seals said inlet port (72).