Target Wheel Position Detection Using Learned Tooth Spacing

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Solution Overview

Problem

Existing crankshaft position monitoring systems face inaccuracies due to variations in tooth spacing on the target wheel, leading to errors in position, velocity, and acceleration calculations, especially at high resolution intervals.

Innovation Solution

The implementation of a control module with a time recording module and a Kalman-based filter that learns and accurately determines the tooth spacing of the target wheel, allowing for precise calculation of position information over small intervals, and uses this information to generate accurate instantaneous position, velocity, and acceleration signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high resolution position sampling is used (small intervals), then position measurement precision is improved, but measurement accuracy deteriorates due to tooth spacing variations

Engineering Contradiction:

Improveposition measurement precisionVSAvoidmeasurement accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary learning of the target wheel's tooth spacing characteristics before actual position measurement. The control module stores the actual spacing between each tooth in memory during a learning phase, which is then used to correct position calculations during operation, eliminating the need for simultaneous measurement and correction

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously comparing the actual tooth spacing (learned and stored) with the nominal tooth spacing, and using this difference to correct position, velocity, and acceleration calculations in real-time, thereby maintaining measurement accuracy despite manufacturing variations

Inventive Principle:

Principle #23Feedback

2Device complexity

If nominal tooth spacing is used for calculations, then device complexity is reduced, but position accuracy deteriorates

Engineering Contradiction:

Improvecalculation system complexityVSAvoidposition accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system pre-learns and stores the actual tooth spacing values in memory during a calibration phase, so that during normal operation, the control module can use these pre-stored values directly in position calculations without performing complex real-time measurements or adjustments

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the calculation parameter from a fixed nominal tooth spacing value to variable actual tooth spacing values that are learned and stored for each specific target wheel, allowing accurate position calculations that account for manufacturing variations without increasing computational complexity

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8176896B2Target wheel position detection systems

Publication Date: 2012.05.15 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A control module for a vehicle includes a time recording module that stores timestamps that correspond to each of N teeth of a target wheel of the vehicle in memory. N is an integer. A position module generates M angular positions based on the timestamps. M is an integer greater than one. Each of the M angular positions corresponds to a space between adjacent ones of the N teeth. A position estimator determines position of the target wheel based on the M positions.