Fuel Injector Energization Control Sludge Compensation

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Solution Overview

Problem

The pressure-balanced fuel injector is prone to sludge accumulation, leading to delayed sliding of the armature, insufficient fuel injection, and deteriorated engine starting characteristics due to resistance from sludge, resulting in reduced engine speed and unstable fuel injection control.

Innovation Solution

A fuel injector energization control method that determines the presence of sludge-related issues and corrects the energization conditions of the fuel injector, extending the energization time and increasing the pull-up current to ensure proper fuel injection and maintain engine speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If the armature is provided to be in a substantially line contact state with the valve seat, then power consumption is reduced and size is reduced, but sludge accumulates in the small clearance and resists armature sliding, deteriorating starting characteristics

Engineering Contradiction:
Improvepower consumptionVSAvoidstarting characteristic
Core Design Contradiction:
Use of energy by stationary objectVSReliability

Solution Approach 1:

The control unit extends the energization time of the electromagnetic coil before the actual injection starts. This preliminary energization allows the armature to overcome the sludge resistance in the line contact clearance and slide smoothly to the open position, ensuring proper fuel injection from the start of engine operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control unit increases the pull-up current value during the preliminary energization phase. By temporarily increasing the current above the normal operating level, the electromagnetic force is enhanced enough to overcome the sludge resistance in the line contact clearance, allowing the armature to slide properly without requiring a larger clearance

Inventive Principle:
Principle #35Parameter changes

2Power

If the armature is provided to be in a substantially line contact state with the valve seat, then the electromagnetic force only has to be large enough to separate the armature from the valve seat, but sludge accumulation in the small clearance causes delay in injection start

Engineering Contradiction:
Improveelectromagnetic forceVSAvoidinjection timing
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The control unit applies preliminary energization to the electromagnetic coil before the injection event. This preliminary action allows the armature to clear the sludge-filled clearance and reach the open position reliably, ensuring that the actual injection starts at the correct time without delay

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control unit implements a two-stage energization process: a preliminary energization phase with extended time and increased pull-up current, followed by the normal injection energization. This periodic variation in energization parameters ensures reliable armature movement despite sludge presence

Inventive Principle:
Principle #19Periodic action

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 effectively compensates for insufficient fuel injection and prevents engine speed reduction, enhancing the reliability and stability of fuel injection control by adjusting energization conditions based on real-time engine state analysis.

Implementation Method 1

an electromagnetic coil that generates an electromagnetic force for driving the armature

Methodology Applied
Scientific EffectElectromagnetic force: Electromagnet

Data Source

PatentEP3467285B1Fuel injector energization control method and common rail fuel injection control apparatus
Publication Date: 2020.12.23 ROBERT BOSCH GMBH
  • EP3467285B1 patent drawingFigure 1
  • EP3467285B1 patent drawingFigure 2
  • EP3467285B1 patent drawingFigure 3

AI summary

Deterioration of a start characteristic of a fuel injector, which is caused by sludge, at a start of an engine is reliably suppressed or prevented. Non-injection energization is performed on fuel injectors 2-1 to 2-n at a start of a vehicle (S102), and a valve closing time at the time is measured (S104). If the valve closing time exceeds a specified range (S106), a cause that deteriorates a starting state of an engine 3 is present, and energization control of the fuel injectors 2-1 to 2-n is executed on the basis of a corrected energization condition until an engine speed exceeds a specified speed (S110, S112) . In this way, the deterioration of the start characteristic at the start of the engine is suppressed or prevented.