Rotary Encoder Error Detection via Speed Model Compensation

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Solution Overview

Problem

Existing methods for determining sensor wheel errors in internal combustion engines have limited accuracy and require significant computational effort, making them inefficient for real-time operation.

Innovation Solution

A method that uses a speed model to determine sensor wheel errors by relating model speeds to actual speeds detected by the sensor wheel, with the condition that the sum of all errors over one revolution is zero, allowing for precise compensation of inaccuracies and simplifying arithmetic operations to determine the error during engine operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex computational methods are used to determine sensor wheel errors, then measurement precision is improved, but device complexity and computational effort increase

Engineering Contradiction:
Improvesensor wheel error detection accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the error determination process into distinct phases: a calibration phase where a speed model is created by comparing measured speeds with reference speeds, and an operational phase where the stored model is used for rapid error calculation. This segmentation allows complex computational work to be performed once during calibration, rather than continuously during operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary action by pre-determining the speed model during a calibration phase before normal engine operation. The calibration phase computes the relationship between measured speeds and actual speeds, storing this model for later use. This preliminary computation eliminates the need for complex real-time calculations during engine operation.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If real-time error determination is performed during engine operation, then productivity is improved, but computational effort and energy consumption increase

Engineering Contradiction:
Improvereal-time error determination capabilityVSAvoidcomputational energy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The speed model is pre-computed during a calibration phase before normal operation, storing the error characteristics for rapid retrieval. During engine operation, the system simply applies the stored model to determine errors, avoiding complex real-time computations and reducing energy consumption.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the computational parameters from complex real-time calculations to simple model-based lookups during operation. The system transitions from computing errors directly from raw sensor data to applying pre-determined correction factors from the speed model, significantly reducing computational energy requirements.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If comprehensive speed modeling is performed, then measurement precision is improved, but storage requirements increase

Engineering Contradiction:
Improveerror compensation accuracyVSAvoiddata storage requirements
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential error characteristics from comprehensive speed measurements during calibration, storing only the necessary correction factors and model parameters. This extraction approach captures the essential error patterns without storing all raw measurement data, reducing storage requirements while maintaining precision.

Inventive Principle:
Principle #2Taking out (Extraction)

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 enables accurate and efficient determination of sensor wheel errors during engine operation, reducing computational complexity and storage requirements, thus improving accuracy and operational efficiency.

Implementation Method 1

voltage pulses are induced in the measuring transducer, for example an inductive sensor, by the markings passing by

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2492475B1Method for automatic detection of a rotary encoder error of a combustion engine
Publication Date: 2014.05.21 VOLKSWAGEN AG
  • EP2492475B1 patent drawingFigure 1~2
  • EP2492475B1 patent drawingFigure 3A~3C
  • EP2492475B1 patent drawingFigure 4~5

AI summary

The method involves providing a speed model, which provides each a model speed for multiple predetermined rotational angles of a working cycle of the internal combustion engine (1). The corresponding speed for multiple predetermined rotational angles of the work cycle is determined by a transmitter wheel (3) and a transmitter wheel sensor (4). An independent claim is also included for a device for automatically determining a transmitter wheel error of an internal combustion engine of a vehicle.