Fuel Injector Control Chamber Standardization

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Solution Overview

Problem

Existing fuel injectors for internal combustion engines face challenges in standardization and cost reduction due to varying overall lengths, leading to inconsistent injection behavior and increased manufacturing complexity.

Innovation Solution

Standardizing the control chamber's storage volume length across different injectors, with a unified storage volume design that includes a 'minirail' storage space within the valve body, allowing for reduced pressure waves and improved injection accuracy by connecting the control chamber to both high and low-pressure areas via throttle-controlled channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If injectors are manufactured with different overall lengths to accommodate different engine applications, then adaptability to various engines is improved, but manufacturing complexity and costs increase due to requiring multiple drilling tools and varying storage volume dimensions

Engineering Contradiction:
Improveadaptability to different engine applicationsVSAvoidmanufacturing process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The injector is divided into functional segments: a standardized control chamber with storage volume that remains constant across all injector lengths, and variable-length sections (such as the valve body extension) that accommodate different engine applications. This segmentation allows the critical control parameters to be standardized while maintaining adaptability through modular length variations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A universal control chamber design with standardized storage volume dimensions is created that can be used across all injector variants regardless of overall length. This universal component ensures consistent injection behavior and control characteristics while allowing the injector assembly to be adapted to different engines through length variations alone.

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

2Adaptability or versatility

If injectors with different storage volume dimensions are manufactured for different lengths, then individual optimization for each application is achieved, but manufacturing precision and coordination of injection behavior deteriorate due to varying control parameters

Engineering Contradiction:
Improveindividual optimization for applicationVSAvoidcoordination of injection behavior
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The control chamber and storage volume are designed with specific local quality characteristics that are maintained consistently across all injector variants. The storage volume dimensions (length, inner diameter, wall thickness) are standardized to ensure uniform pressure wave behavior and injection characteristics, while only the non-critical external length of the injector varies for different applications.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If multiple drilling tools are provided for manufacturing storage volumes of different dimensions, then customization for different injector lengths is enabled, but manufacturing costs increase

Engineering Contradiction:
Improvecustomization capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

A single standardized storage volume design serves all injector variants universally. The control chamber is drilled with fixed dimensions and positioned at a standardized location, allowing one drilling tool and one manufacturing process to produce the control parameters for all injector lengths, thereby eliminating the need for multiple customized drilling operations.

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 approach standardizes injector manufacturing, reduces costs, enhances injection accuracy, and improves multiple injection capabilities by minimizing pressure fluctuations and simplifying control units, while maintaining consistent performance across different injector lengths.

Implementation Method 1

These pressure fluctuations are dampened by adding a storage volume to the injector as a so-called 'minirail', the storage volume being under high fuel pressure.

Methodology Applied
Scientific EffectPressure wave damping: Damping

Implementation Method 2

The control chamber is connected to the high-pressure area of the fuel system via an inlet channel with an activated inlet throttle, while the control chamber is connected to the low-pressure area of the fuel system via an outlet channel with an activated outlet throttle, controlled by the valve.

Methodology Applied
Scientific EffectThrottle control: Valve

Data Source

PatentEP2721282B1Method of manufacturing of an injector, in particular of an fuel injector for an internal combustion engine
Publication Date: 2018.07.11 ROBERT BOSCH GMBH
  • EP2721282B1 patent drawingFigure 1
  • EP2721282B1 patent drawingFigure 2

AI summary

The invention relates to an injector, in particular a fuel injector for an internal combustion engine, having an actuator module (8) controlling a valve (15) for adjusting a flow rate of a fluid medium, wherein the valve (15) links a control chamber (14) for controlling a control piston to a low pressure area. According to the invention an injector is provided which is improved with regard to the process for the manufacture thereof. This is achieved in that the control chamber (4) is connected to a storage volume, wherein the length of the volume chamber is the same for different injectors, irrespective of the injector.