Fuel Injector Coupler Refilling via Return Pressure

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Solution Overview

Problem

Hydraulic couplers in piezoelectrically driven fuel injectors often become partially or completely emptied, leading to impaired injector function, engine misfires, and non-starters due to air accumulation, which complicates fault localization and requires costly replacement of injectors.

Innovation Solution

A method involving a pressure generator connected to the return line of the fuel injector to generate increased return pressure, allowing for refilling of the coupler and checking the tightness of the injector and return system, thereby restoring injector function without the need for spare parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the coupler space is not completely filled with fuel and air cushion accumulates, then the injector function is impaired and injection volume is reduced, but replacing injectors with spare parts is time-consuming and costly

Engineering Contradiction:
Improveinjector functionVSAvoidtroubleshooting time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system uses its own feed pump and fuel supply to refill the coupler space, eliminating the need for external refilling equipment or injector replacement. The injector serves itself by utilizing existing system components to restore proper fuel filling in the coupler space.

Inventive Principle:
Principle #25Self-service

2Reliability

If the coupler space is not completely filled with fuel and air cushion accumulates, then the injector function is impaired, but exchanging injectors increases cost and complexity

Engineering Contradiction:
Improveinjector functionVSAvoidfault isolation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system monitors the coupler filling status and provides feedback through the refilling process. By observing whether the coupler fills properly using the existing feed pump and fuel supply, the system can identify faults in the return system or pressure control valve without complex diagnostic equipment.

Inventive Principle:
Principle #23Feedback

3Reliability

If pressure generator is used to generate return pressure for refilling coupler, then injector function is restored, but additional equipment is required

Engineering Contradiction:
Improveinjector functionVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses its own feed pump and fuel supply to refill the coupler space, eliminating the need for external refilling equipment or injector replacement. The injector serves itself by utilizing existing system components to restore proper fuel filling in the coupler space.

Inventive Principle:
Principle #25Self-service

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 method quickly and cost-effectively restores injector function, simplifies fault isolation, and reduces the time and expense associated with replacing injectors by ensuring optimal return pressure and detecting defects in the return system.

Implementation Method 1

The pressure generator generates the increased pressure in the return line by compressing a gas, in particular air

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

An incompressible volume of liquid in the coupler space then enables the force to be transmitted from the actuator to the switching valve of the injector

Methodology Applied
Scientific EffectHydraulic pressure transmission: Hydraulic Press

Data Source

PatentEP2683932B1Method for refilling and checking the leak-tightness of a fuel injector
Publication Date: 2018.03.28 ROBERT BOSCH GMBH
  • EP2683932B1 patent drawingFigure 1
  • EP2683932B1 patent drawingFigure 2

AI summary

A method for refilling an emptied hydraulic coupler of a fuel injector (30) has the steps: connecting a pressure generator (36) to a return line (32) of the fuel injector (30); operating the pressure generator (36) in order to generate a return pressure in the return line (32); operating the fuel injector (30). The method may also include the step of monitoring the pressure level in the return line.