Injection Valve Diagnostic Mode for Metering Accuracy

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Solution Overview

Problem

Current methods for assessing the injection behavior of injection valves in internal combustion engines are not accurate and reliable, especially in small control areas, leading to decreased metering accuracy and increased scattering with reduced drive periods.

Innovation Solution

A method is introduced that involves transferring the engine to a special operating mode with defined drive parameters, allowing for the detection and evaluation of injection behavior through valve-side diagnostics, including specific settings of rail pressure, injection pattern, and fuel type, enabling more precise and rapid assessment of injection valve performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the drive period of the injection valve is reduced to enable small control operations, then the injection valve can operate in a wider range, but the metering accuracy decreases significantly and scattering increases

Engineering Contradiction:
Improveoperating range of injection valveVSAvoidmetering accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by switching from regular operating parameters to specially defined diagnostic parameters during the diagnostic period. This includes setting specific rail pressure values, injection patterns, and pause times that create optimal conditions for measuring injection behavior. By changing these parameters, the system achieves both wide operating range coverage and high measurement precision simultaneously.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements preliminary action by transferring the engine to a special operating mode before performing the diagnostic measurement. This preliminary setup establishes defined drive parameters and operating conditions that ensure accurate measurement results. The diagnostic mode is prepared in advance with specific rail pressure, injection patterns, and timing parameters to guarantee measurement quality.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If engine output-side evaluation of air ratio lambda is used to assess injection valve behavior, then measurement can be performed during regular operation, but the detection reliability is insufficient compared to valve-side detection

Engineering Contradiction:
Improvemeasurement during regular operationVSAvoiddetection reliability of injection valve behavior
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces an intermediary approach by using a detection device that directly monitors valve behavior parameters rather than relying on indirect engine output measurements. The detection device acts as an intermediary between the injection valve and the evaluation system, providing direct measurement data about valve opening behavior, timing, and injection characteristics, which significantly improves detection reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the indirect mechanical/engine output-based evaluation method with a direct electronic detection and evaluation system. Instead of measuring engine output parameters like air ratio lambda indirectly, the system uses electronic sensors and processing to directly detect valve behavior, substituting the mechanical evaluation chain with an electronic measurement system that provides more reliable data.

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

3Device complexity

If diagnostic measurements are performed without defined drive parameters, then the measurement process is simpler, but the detection quality and reproducibility are reduced

Engineering Contradiction:
Improvemeasurement process complexityVSAvoiddetection quality of injection valve behavior
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the drive parameters adaptable and adjustable based on diagnostic requirements. The system dynamically switches between regular operating parameters and diagnostic parameters, and can adjust rail pressure, injection patterns, and timing during the diagnostic period. This dynamic parameter adjustment ensures optimal detection quality while maintaining manageable system complexity through automated control.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2758650B1Method for assessing an injection behaviour of at least one injection valve in an internal combustion engine and operating method for an internal combustion engine
Publication Date: 2021.06.16 ROBERT BOSCH GMBH
  • EP2758650B1 patent drawingFigure 1
  • EP2758650B1 patent drawingFigure 2
  • EP2758650B1 patent drawingFigure 3

AI summary

A method for assessing an injection behaviour of at least one injection valve (109) in an internal combustion engine, comprising: switching the internal combustion engine to a special operating mode (S) defined by control parameters, and operating the internal combustion engine in the special operating mode (S) during a diagnostic period, wherein at least one operating parameter (321, 322, 323) of the internal combustion engine is determined at least during the diagnostic period and at least one characteristic value of the injection behaviour of at least one injection valve (109) is recorded at least during a portion of the diagnostic period and is evaluated on the basis of at least one operating parameter (321, 322, 323).