Valve Lash Setting Using Torque Regression

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Solution Overview

Problem

Existing methods for setting valve lash in internal combustion engines are imprecise, labor-intensive, and fail to account for mechanical variations, leading to inconsistent engine performance and reduced fuel efficiency.

Innovation Solution

An automated torque tool system with double spindles and programmable control unit that measures and adjusts valve lash using torque and angular displacement sensors, employing a linear regression method to determine the zero lash position and calculate the necessary adjustments for precise valve clearance settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual adjustment with feeler gauges is used, then the valve lash can be adjusted, but the measurement precision is poor due to inconsistent feeler gauge use

Engineering Contradiction:

Improvevalve lash measurement precisionVSAvoidease of manual measurement

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the manual mechanical measurement system (feeler gauges and manual adjustment) with an automated torque-based measurement system. The torque tool applies controlled torque to the adjuster screw and measures the angular displacement, eliminating the need for manual feeler gauge measurements and providing consistent, precise valve lash measurements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The automated torque tool performs the measurement and adjustment operations autonomously without requiring manual intervention for each measurement. The system automatically applies torque, measures angular displacement, determines zero lash position, and calculates adjustments, making the process self-service and eliminating human error in measurements.

Inventive Principle:

Principle #25Self-service

2Productivity

If manual adjustment process is used, then the valve lash can be set, but the productivity is low due to labor intensity and time consumption

Engineering Contradiction:

Improvevalve lash setting speedVSAvoidtime for manual adjustment

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical adjustment operations with an automated torque tool that electronically applies torque and measures angular displacement. This substitution eliminates the time-consuming manual measurement and adjustment process, enabling rapid valve lash setting in automated engine assembly lines.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs preliminary actions by automatically determining the zero lash position through torque application and angular displacement measurement before calculating the final adjustment. This preliminary characterization of the valve assembly's mechanical state enables rapid, accurate adjustment without repeated manual measurements.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If empirically derived averages are used to estimate zero crossing point, then the process can be simplified, but the manufacturing precision deteriorates due to tolerance stack-ups

Engineering Contradiction:

Improvevalve lash setting accuracyVSAvoidcomplexity of measurement system

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements feedback by measuring the actual angular displacement of the adjuster screw during torque application and using this real-time data to determine the zero lash position. The system continuously monitors the torque-angular displacement relationship and calculates the precise zero crossing point based on actual measurements rather than empirical averages, compensating for tolerance variations.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes the measurement parameter from manual linear measurement (feeler gauges) to torque-based angular measurement. By applying controlled torque and measuring the resulting angular displacement, the system transforms the measurement into a parameter that is less sensitive to mechanical tolerances and assembly variations, improving precision without requiring overly complex measurement apparatus.

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

The system provides accurate, fast, and repeatable valve lash settings, reducing cycle time and accounting for individual engine variations, thereby improving engine performance and efficiency.

Implementation Method 1

a torque transducer to measure torque applied to the adjuster screw

Methodology Applied

Scientific EffectTorque transduction:

Implementation Method 2

an angular displacement sensor to measure angular position and displacement of the adjuster screw

Methodology Applied

Scientific EffectAngular displacement sensing:

Implementation Method 3

employing a linear regression method to determine the zero lash position and calculate the necessary adjustments

Methodology Applied

Scientific EffectLinear regression analysis:

Data Source

PatentUS8646426B2Valve lash setting process

Publication Date: 2014.02.11 ATLAS COPCO IND TECHNIQUE AB INTELLECTUAL PROPERTY DEPARTMENT

AI summary

A valve lash setting method for setting a predetermined lash in a valve assembly for internal combustion engines. The method includes generating a torque curve and using a linear regression calculation to define a zero crossing point from which a predetermined final lash position of an adjusting screw can be set and secured.