Common Rail Pressure Sensor Integration via Transverse Wall

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Solution Overview

Problem

Existing fuel injection equipment faces challenges in efficiently integrating a pressure sensor with the common rail due to complex machining requirements and space constraints, particularly in accommodating the sensor's protruding nature and ensuring accurate pressure measurement under high fuel pressures.

Innovation Solution

An integrated arrangement where a transverse wall within the common rail forms a recess at one end, housing a force sensing device, such as a strain gauge, on its outer face, which senses the pressure-induced deformation and transmits signals to the command unit, reducing manufacturing complexity and space requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a pressure sensor is mounted outside the common rail in a recess with thinned wall, then the sensor can measure fuel pressure through wall flexing, but the rail structure becomes more complex and requires additional machining operations

Engineering Contradiction:
Improvepressure measurementVSAvoidrail structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The pressure sensor is integrated directly into the common rail body, merging two previously separate components (sensor and rail) into a single unified structure. This eliminates the need for external mounting and reduces overall structural complexity while maintaining measurement functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pressure sensor is nested within the common rail structure, with the sensor housing formed as an integral part of the rail body. The sensor is positioned inside the rail's internal space, utilizing the existing structural volume rather than adding external protrusions.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Measurement precision

If the pressure sensor forms a protruding member larger than the rail, then the sensor can be adequately housed, but specific space needs to be reserved on the engine block

Engineering Contradiction:
Improvepressure sensor functionalityVSAvoidspace requirement
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

By merging the sensor housing with the common rail body, the sensor no longer requires separate external space. The rail itself serves as the mounting structure, eliminating the need for additional reserved space on the engine block.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensor is positioned within the internal longitudinal space of the common rail rather than protruding externally. This utilizes the existing three-dimensional volume of the rail structure, converting a potential external volume requirement into an internal space utilization.

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

3Adaptability or versatility

If complex machining operations are performed to enable complementary arrangement of the pressure sensor and limiting valve, then both components can be integrated, but manufacturing complexity increases

Engineering Contradiction:
Improvecomponent integrationVSAvoidmachining operations
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The common rail body is segmented into distinct functional zones: a longitudinal internal space for the pressure sensor and transverse internal spaces for the pressure limiting valves. This segmentation allows each component to be positioned in optimized locations without requiring complex intersecting machining operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The common rail body serves multiple functions simultaneously: it stores fuel, houses the pressure sensor, and accommodates pressure limiting valves. This multi-functionality is achieved through a standardized elongated cylindrical structure that naturally provides both longitudinal and transverse internal spaces.

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

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 allows for precise pressure measurement and reduced manufacturing complexity while minimizing the space needed for the sensor assembly on the engine block, enhancing the overall efficiency and reliability of the fuel injection system.

Implementation Method 1

said force sensing device is a strain gauge

Methodology Applied
Scientific EffectStrain gauge measurement: Piezoresistive Effect

Data Source

PatentEP3315762B1Integrated arrangement of a common rail and a pressure sensor
Publication Date: 2020.08.05 DELPHI TECH IP LTD
  • EP3315762B1 patent drawingFigure 1
  • EP3315762B1 patent drawingFigure 2
  • EP3315762B1 patent drawingFigure 3~4

AI summary

A common rail (12) adapted to be arranged in a fuel injection equipment and comprising comprises a transverse wall (34) arranged in the vicinity of a first end (16) of the rail, said transverse wall (34) sealingly closing said internal space (S) so that, in use, pressurised fuel retained in the inner space (S) exerts forces on an inner face (36) of said transverse wall (34).