Fuel Injector Actuator Control for Small Injection Quantities

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Solution Overview

Problem

Existing methods for operating actuators in fuel injectors of internal combustion engines fail to achieve precise control over small injection quantities due to limitations in minimizing the opening time of the switching valve, leading to inefficiencies in handling small fuel quantities and stability issues.

Innovation Solution

The actuator is controlled to switch directly from an opening movement to a closing movement, reducing the minimum opening time of the switching valve by avoiding the stroke stop, allowing for arbitrarily short opening times and improved small-quantity capability, with the charge quantity adjusted based on various parameters such as injection type, pressure, and temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the actuator is controlled to move the switching valve to the stroke stop to ensure complete opening, then the opening time is sufficient for complete fuel injection, but the minimum opening time cannot be reduced below a certain limit due to the time spent at the stroke stop

Engineering Contradiction:
Improveinjection quantity precisionVSAvoidminimum opening time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The actuator is controlled to apply partial action by reducing the charge quantity during the charging process, which prevents the switching valve from reaching the stroke stop. This allows the valve to be moved back to the closed position before completing the full stroke, thereby eliminating the time spent at the stroke stop and enabling arbitrarily short opening times while maintaining precise control over small injection quantities.

Inventive Principle:
Principle #16Partial or excessive action

2Quantity of substance

If the actuator is controlled conventionally to move the switching valve to the stroke stop, then the injection quantity can be maximized, but the small-quantity capability is compromised and injection stability deteriorates

Engineering Contradiction:
Improveinjection quantityVSAvoidinjection stability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The control system dynamically adjusts the charge quantity of the actuator based on the required injection quantity. For small injection quantities, the charge quantity is reduced to prevent the switching valve from reaching the stroke stop, enabling precise control. For large injection quantities, conventional control can be used. This dynamic adjustment maintains injection stability across the entire operating range.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the actuator charging time is extended to ensure complete actuation, then the switching valve reaches the stroke stop reliably, but the response time for small injection quantities increases

Engineering Contradiction:
Improveactuator actuation reliabilityVSAvoidresponse speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The charge quantity parameter of the actuator is changed during the charging process based on the required injection quantity. By reducing the charge quantity for small injection demands, the switching valve is prevented from reaching the stroke stop, thereby reducing the opening time and improving response speed while maintaining actuation reliability through controlled parameter adjustment.

Inventive Principle:
Principle #35Parameter changes

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 enhances the injector's ability to handle small quantities with high robustness and stability, enabling precise control over injection quantities and improved dynamic performance by reducing the opening time of the switching valve, thus achieving better injection stability and flexibility.

Implementation Method 1

the actuator is electrically controllable

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnetic Induction

Data Source

PatentEP3258091B1Method for operating an actuator of an injector, and a corresponding actuator
Publication Date: 2021.07.14 ROBERT BOSCH GMBH
  • EP3258091B1 patent drawingFigure 1
  • EP3258091B1 patent drawingFigure 2~3
  • EP3258091B1 patent drawingFigure 4a~4e

AI summary

The invention relates to a method for operating an actuator 8 for actuating a switching valve 6 that determines the injection quantity of an injector 1 and sets a fluid pressure in a switching chamber 7 of the injector 1, wherein the actuator 8 is electrically controllable. According to the invention, a method for operating an actuator 8 is provided with which precise, demand-oriented control of the injection quantity of the injector 1 is possible. This is achieved by the fact that the actuator 8 can be controlled such that the switching valve 6 can be switched from an opening movement before contact with a stroke stop to a closing movement.