Injection Valve Opening Delay Determination

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Solution Overview

Problem

Existing methods for optimizing fuel injection in internal combustion engines struggle with precise control due to inaccuracies in valve elements and magnet armature play, leading to variations in opening delay times, which affect fuel metering and engine operation.

Innovation Solution

A method that determines the opening delay time of the injection valve by analyzing the activation period where the valve remains closed, using a mathematical formula to calculate this time, and employs a time derivative of the voltage gradient to detect valve seating, allowing for precise control duration adjustments without affecting engine operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional fuel injection control methods are used, then the injection process is simple to implement, but the fuel metering precision is insufficient due to opening delay time variations caused by valve element inaccuracies and magnet armature play

Engineering Contradiction:
Improvefuel metering precisionVSAvoidcontrol method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the control parameter from fixed injection timing to dynamically adjusted injection timing based on the determined opening delay time. By calculating the opening delay time using the critical control duration and compensating for it in the injection control, the system achieves precise fuel metering despite variations in valve element characteristics and magnet armature play.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the control duration is adjusted to compensate for opening delay time, then the fuel injection precision is improved, but the determination process increases the complexity of the control system

Engineering Contradiction:
Improveinjection timing precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs self-characterization by automatically determining the opening delay time for each injection valve through the critical control duration method. The control unit executes the determination process and uses the results to compensate for timing variations, making the system self-adjusting without requiring external calibration or complex additional hardware.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If the critical control duration method is used to determine opening delay time, then the fuel injection control is optimized, but the determination process requires additional measurement and calculation steps

Engineering Contradiction:
Improveinjection control precisionVSAvoidvalve seating detection difficulty
Core Design Contradiction:
Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces direct mechanical measurement of valve element movement with electrical signal analysis. By monitoring the electrical signals from the injection valve and detecting the critical control duration where the valve just fails to open, the system indirectly determines the opening delay time without requiring complex mechanical sensors or direct physical measurement of valve movement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enables precise fuel metering and refined control of fuel injection, reducing fuel spread and smoothing engine operation, while minimizing impact on torque and emissions.

Implementation Method 1

injection valves (18a to 18d), in which fuel is injected directly into the respective combustion chambers (20a to 20d) by injection valves (18a to 18d) with a valve needle (28) that is actuated, for example, by an electromagnetic actuating device (24)

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnetic Induction

Implementation Method 2

The method according to the invention provides that the electrical operating variable is a time derivative (gradient) of a voltage of a magnetic coil of the electromagnetic actuating device, and that a closing of the injection valve is inferred from a minimum of the gradient

Methodology Applied
Scientific EffectTime derivative analysis of voltage:

Data Source

PatentEP2449238B1Method and apparatus for controlling an internal combustion engine
Publication Date: 2017.04.26 ROBERT BOSCH GMBH
  • EP2449238B1 patent drawingFigure 1
  • EP2449238B1 patent drawingFigure 2~3
  • EP2449238B1 patent drawingFigure 4

AI summary

The present invention relates to a method for operating an internal combustion engine (10), wherein fuel reaches at least one combustion chamber (20) by means of at least one injection valve (18) comprising an electro-magnetic actuating device (24). By varying the control period of the injection valve (18) and analyzing a course of an electric operating variable of the injection valve (18) characterizing a movement of a valve element (28) of the injection valve (18), the opening delay time of the injection valve (18) is determined.