6 0 7 MB
Damper Basics Damper Design, Testing and Tuning
This document is property of Kaz Technologies Not authorized for use by outside organizations
Presented to Formula SAE By Jim Kasprzak
May 15, 2010
This document is property of Kaz Technologies Not authorized for use by outside organizations
Damper Basics It is thought by many that dampers are a black art That there is some “magic” to developing and tuning dampers
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Basics We are here to dispel those myths and give you tools to develop dampers However, there is art in damper tuning The art is optimizing the damper using engineering knowledge &the proper tools This document is property of Kaz Technologies. Not authorized for use by outside organizations
“Sometimes I think that I would have enjoyed
racing more in the days of the friction shock. Since you couldn’t do anything much to them or with them, I would have spent a lot less time being confused.” Carroll Smith Tune to Win, 1978 This document is property of Kaz Technologies. Not authorized for use by outside organizations
PLEASE ask questions at any time
This document is property of Kaz Technologies Not authorized for use by outside organizations
Course Outline
Damper Basics Inside the Damper Damper Testing Damper Design Advanced Tools The Last Word
This document is property of Kaz Technologies. Not authorized for use by outside organizations
KAZ Technologies KAZ TECHNOLOGIES started in 1995 Staff of 5 Engineers
Over 85 years of combined racing & automotive engineering experience
Extensive vehicle suspension, ride and handling experience
Damper design, development, testing and manufacturing All types of springs, stabilizer bars, oil seals, shock absorbers and struts Ride & handling on standard suspension and advanced technologies NVH, tire testing, vehicle stability systems, race chassis development 7-Post and 4-Post test development and testing
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Experience Racing experience includes: o Race driving o Race engineering o Chassis/Suspension development o Data acquisition and analysis o Suspension design, analysis & fabrication o Shock absorber development o 7-Post Testing
This document is property of Kaz Technologies. Not authorized for use by outside organizations
KAZ TECHNOLOGIES GM Racing
Resident 7-post and shock technical specialists 7-post testing for GM Racing 7-Post & damper testing tools Race engineering
Other
Race engineering Damper design & development Damper sales & service
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Jim Kasprzak-Race Engineering 36 years racing experience Developed 7-Post testing for GM Expertise includes:
Race Engineering 7-Post testing Suspension engineering Shock design, development & tuning Vehicle tuning
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Jim Kasprzak-Automotive 31 years automotive experience Arvin Ride Control Director, Original Equipment Engineering Director, New Product Development
Monroe Auto Equipment Chief Engineer, Electronic Suspensions Manager, Suspension System Programs
Two shock design patents
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Course Outline
Damper Basics Inside the Damper Damper Testing Damper Design Advanced Tools The Final Word
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Basics
A shock absorber is a damper! Functions of a damper Resonant frequencies How much damping?
This document is property of Kaz Technologies. Not authorized for use by outside organizations
A Shock is a DAMPER! Dampens sprung and unsprung mass Dissipates this energy into heat Only produces force when in motion Dampers are VELOCITY sensitive device Force produced is proportional to velocity
Damping is also a function of acceleration
This document is property of Kaz Technologies. Not authorized for use by outside organizations
A Shock is a DAMPER! Sprung Mass (Chassis) Spring
Damper
Unsprung Mass
This document is property of Kaz Technologies. Not authorized for use by outside organizations
A Shock is a DAMPER! The damper controls the suspension In broad terms: Rebound controls sprung mass Compression controls unsprung mass
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Functions of a Damper
This document is property of Kaz Technologies Not authorized for use by outside organizations
Functions of a Damper How do we use dampers on vehicles? Primary Function Dampen sprung & unsprung resonant frequencies
Secondary Function Controls vehicle at pitch, heave and roll resonant frequencies Controls rate of weight transfer Braking, corner entry, acceleration
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Functions of a Damper At best, dampers are “The frosting on the cake” Dampens vibrations at resonant frequencies Controls rate of weight transfer Enhances vehicle performance
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Functions of a Damper In worst case, dampers “Hold the cake together!” Compensates for structural deficiencies Controls heave, pitch, roll imbalances Used to compensate for deficiencies in design or other components Compensates for lack of suspension travel
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Resonant Frequencies
This document is property of Kaz Technologies Not authorized for use by outside organizations
Resonant Frequencies A suspension is two spring/mass/damper systems in series
Sprung Mass (Chassis) Spring
Damper
Body, chassis spring and damper Suspension and tire
Unsprung Mass Suspension Tire Spring
Tire Damping
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Resonant Frequencies Sprung Mass
Unsprung Mass
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Typical Natural Frequencies Sprung Mass FSAE Passenger Car NASCAR Cup Car All 4 corners different!! Indy Car
2.0 – 4 Hz 1 – 2 Hz 1.5 – 4 Hz 3 -5 Hz
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Typical Natural Frequencies Unsprung Mass
FSAE Passenger Car NASCAR Cup Car Indy Car
22 - 26 Hz 10 - 12 Hz 15 - 17 Hz 23 - 27 Hz
This document is property of Kaz Technologies. Not authorized for use by outside organizations
How Much Damping?
This document is property of Kaz Technologies Not authorized for use by outside organizations
How Much Damping? Resonance
Critically Damped
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Passenger Car
Non-Aero Racecars
Critical Damping
Aero Racecars Ride: 0.7-1.1 Roll: 6.0-9.0
Milliken
This document is property of Kaz Technologies. Not authorized for use by outside organizations
How Much Damping? Critical Damping
This document is property of Kaz Technologies. Not authorized for use by outside organizations
How Much Damping? Critical Damping
This document is property of Kaz Technologies. Not authorized for use by outside organizations
How Much Damping? Proper Damping Ratio 0.2 -0.4 total system damping Great for theoretical calculations, but not very practical!
This document is property of Kaz Technologies. Not authorized for use by outside organizations
How Much Damping? Effects of Different Damping
Gillespie
This document is property of Kaz Technologies. Not authorized for use by outside organizations
How much Damping? Tire Force Variation Considerations Damping is only required at resonant frequencies Primarily sprung & unsprung mass resonance Damping required to control resonance
Damping at other frequencies increases tire force variation
This document is property of Kaz Technologies. Not authorized for use by outside organizations
How much Damping?
Courtesy of Kaz Technologies and GM Racing
This document is property of Kaz Technologies. Not authorized for use by outside organizations
How much Damping? So, how much damping? The correct amount
To control resonances To control pitch and roll rates To control suspension travel Minimize tire force variation
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Questions?
This document is property of Kaz Technologies Not authorized for use by outside organizations
Inside the Damper
Damping force calculations Gas pressure Damper valve operation Compression pressure balance
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damping Force Calculations Monotube
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damping Force Calculations Monotube with Basevalve
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Gas Pressure
This document is property of Kaz Technologies Not authorized for use by outside organizations
Gas Pressure Purpose Pressurizes oil in damper Reduces hysteresis
Creates static rod force Provides the pressure for gas spring However, spring rate is low
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Gas Pressure Calculations Gas Force
Ideal Gas Law Gas Spring Rate
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Gas Pressure In Monotube Balances the pressure in compression chamber (P2) Prevents cavitation or lag High gas pressure typically required Produces high friction and static rod force
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Gas Pressure In Monotube with Basevalve Compensates for minor fluid loss Pressurizes oil in damper Balances pressure across base valve P4 vs. P3
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Valve Operation
This document is property of Kaz Technologies Not authorized for use by outside organizations
Rebound Flow Low Speed Rebound Controls 0 – 2 in/sec damping In valving Bleed holes By-pass jet Leakage
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Rebound – Low Speed
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Rebound Flow Mid Speed Rebound Controls 2-8 in/sec damping In valving Disc preload Disc stack
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Rebound – Mid Speed
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Rebound Flow High Speed Rebound Controls > 8 in/sec damping In valving Piston ports Restriction of disc stack travel
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Rebound – High Speed
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Compression Flow Low Speed Compression Controls 0 – 2 in/sec damping In valving Bleed holes By-pass jet Leakage
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Compression – Low Speed
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Compression Flow Mid Speed Compression Controls 2-8 in/sec damping In valving Disc preload Disc stack
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Compression – Mid Speed
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Compression Flow High Speed Compression Controls > 8 in/sec damping In valving Piston ports Restriction of disc stack travel
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Compression – High Speed
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Compression Pressure Balance
This document is property of Kaz Technologies Not authorized for use by outside organizations
Compression Pressure Balance To maintain hydraulic integrity, you must have a balance of pressure drops in compression In Monotube between the piston and the gas piston In Monotube with base valve, between piston, base valve and gas pistion
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Compression Pressure Balance Monotube Pressure in gas chamber must always be greater than compression chamber
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Compression Pressure Balance Monotube with Base valve Pressure drop across base valve must always be greater than across piston And Pressure in gas chamber must always be greater than below base valve
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Compression Pressure Balance What results from pressure imbalance? Cavitation Hydraulic lag Hysteresis
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Cavitation What is Cavitation? Negative pressure in rebound or compression chamber Creates “void” in chamber Result is “lag” in force
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Cavitation Compression Pressure
Base Valve Pressure
Rebound Pressure
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Cavitation Cavitation
No Cavitation
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Cavitation
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Cavitation
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Cavitation
Hydraulic Lag
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Cavitation Red = 100 psi Green = 75 psi
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Cavitation
Green = 75 psi Red = 100 psi
Cavitation is not always evident in Force/Velocity graph!
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Hysteresis Red = Baseline Green = Hysteresis
Hysteresis
Hysteresis is also caused by compression pressure imbalance
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Proper Pressure Balance
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Questions?
This document is property of Kaz Technologies Not authorized for use by outside organizations
Damper Testing
Traditional damper testing Traditional damper dyno curves Damper curve analysis Proper test methods
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Traditional Damper Testing Sine wave input Fixed stroke Single speed Single speed plot
Or Multiple speed Peak force plot
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Traditional Damper Testing Mechanical Damper Tester Fixed stroke Mechanically adjustable
Scotch yoke or crank design Fixed speed for each test Variable speed for multiple tests
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Traditional Damper Curves Standard Roehrig Curves
Force – Velocity Force – Absolute Velocity Compression Open, Rebound Closed Rebound Open, Compression Closed Force – Displacement PVP – Peak Velocity Plot
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Dyno Curves
This document is property of Kaz Technologies Not authorized for use by outside organizations
Roehrig Control Panel
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Force - Velocity Compression
Rebound
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Force - Absolute Velocity Compression
Rebound
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Compression Open – Rebound Closed Compression
Rebound
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Rebound Open – Compression Closed Compression
Rebound
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Force - Displacement Compression
Rebound
This document is property of Kaz Technologies. Not authorized for use by outside organizations
PVP – Peak Velocity Plot What is a PVP Plot? A collection of forces at peak velocities Each force is plotted as a point A line is drawn through each point to generate the curve Representation of peak force at each velocity
This document is property of Kaz Technologies. Not authorized for use by outside organizations
PVP – Peak Velocity Plot 17 Peak Velocities
Compression
Curve connects Individual points Rebound
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Complete Curve at Single Velocity Compression
Rebound
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Single Speed Plot Typical Plot 1 or 2 inch fixed stroke 10 in/sec peak velocity Only one speed
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Single Speed Plot
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Single Speed Plot Pluses Has become the default standard Because the standard, easy comparison between teams Easy to compare your data to another team’s
Good overall view of damper forces
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Single Speed Plot Minuses Only one speed Ignores acceleration affects
Shows poor representation of low speed controls Poor for comparison of damping performance at low velocities
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Multiple Speed Plot
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Multiple Speed Plot Pluses Able to see effects of acceleration Better analysis at each specific velocity Focus on velocity car is working Observe how valving is working at each specific velocity
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Multiple Speed Plot Minuses No standardized set of velocities Hard to compare results with other teams
Analysis is more difficult
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Dyno Curve Analysis
This document is property of Kaz Technologies Not authorized for use by outside organizations
Dyno Curve Analysis Want smooth, uniform curve
No lags No signs of cavitation No incongruities Minimal hysteresis
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Hydraulic Lag
Hydraulic Lag
This document is property of Kaz Technologies. Not authorized for use by outside organizations
No Cavitation
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Minor Cavitation
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Slight Cavitation
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Cavitation
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Massive Cavitation
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Incongruity
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Hysteresis
Hysteresis
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Proper Curve
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Dyno Curve Analysis Use opening side of curve This is the initial force seen by the vehicle during any event
Analyze entire cycle – NOT PVP Use Force/Velocity and Force/Displacement
Analyze multiple speeds
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Force – Absolute Velocity
Compression Open
Rebound Open
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Force – Displacement
Compression Open
Rebound Open
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Test Methods
This document is property of Kaz Technologies Not authorized for use by outside organizations
Proper Damper Test Methods
Zero out damper weight Subtract gas force Test shock at operating temperature Test & analyze multiple speeds Analyze entire cycle, not PVP Use compression and rebound open
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Questions?
This document is property of Kaz Technologies Not authorized for use by outside organizations
Damper Design
Damper architecture Adjusters Design process Tuning process Tuning guides Damper care & feeding
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Architecture
Twin tube Monotube Monotube with basevalve Twin tube with piggyback reservoir Monotube with remore reservoir Monotube with piggyback reservior
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Architecture Choose the design that serves the application
Function Packaging Performance Price
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Twin Tube Primarily used in OE applications Inexpensive Has to be mounted rod up Valving in piston and base valve Typically smaller piston OD than monotube No separation between oil & gas Pressure balance required
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Monotube Compression & rebound valving in piston No base valve Typically high gas pressure
Pressure balance between piston and gas force required
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Monotube with Base Valve Valving in piston and base valve Can run low gas pressure Pressure balance between piston and base valve required Pressure balance between base valve and gas pressure required
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Monotube with Remote Reservoir Valving in piston and base valve Base valve typically in reservoir Remote reservoir for packaging Can cause hysteresis and lags
Same pressure balance as monotube with base valve
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Monotube with Piggyback Reservoir
Valving in piston and base valve Base valve typically in reservoir Shorter length than monotube Same pressure balance as monotube with base valve
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Twin Tube with Piggyback Reservoir Valving in piston and base valve Base valve typically in reservoir Piston OD typically smaller than monotube Same pressure balance as monotube with base valve
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Adjusters
This document is property of Kaz Technologies Not authorized for use by outside organizations
Adjusters Various types of adjusters
Rebound Compression Rebound & compression High speed compression & rebound Low speed compression & rebound
Must decide what is important ! This document is property of Kaz Technologies. Not authorized for use by outside organizations
Adjusters Multiple adjusters interact High speed and low speed adjusters interact They are not totally independent The setting of one adjuster will often determine the effectiveness of the other adjuster
This document is property of Kaz Technologies. Not authorized for use by outside organizations
High Speed Compression Adjustment
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Low Speed Compression Adjustment
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Adjusters Single Adjusters Typically rebound in rod Typically compression in reservoir Can adjust low speed, high speed or both
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Design Process
This document is property of Kaz Technologies Not authorized for use by outside organizations
Damper Design Process Design Considerations
Damper architecture Damper features Packaging on vehicle Dimensions Performance characteristics Initial damping characteristics
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Architecture Choose the architecture that serves the application
Function Packaging Performance Price
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Features Choose the features that serve your application
Piston diameter Number and type of adjustments Piston and valving design Base valve design Jounce bumper?
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Packaging on Vehicle
Mountings Travel or stroke Is the damper a travel limiter? Coil-over spring travel on shock Jounce bumper travel
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Dimensions
Compressed and extended length Stroke or travel Mounting dimensions External tube diameters Spring dimensions Jounce bumper dimensions
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Performance Characteristics
Damping requirements Damping adjustment ranges Spring rates and travels Jounce bumper engagement point, rate and travel
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Initial Damping Characteristics How do you determine?
Damper supplier recommendations Experience or records Calculations Simulation Guess
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Tuning Process
This document is property of Kaz Technologies Not authorized for use by outside organizations
Tuning Process
Damping curves from dyno test Fit check on vehicle Basic vehicle testing Advanced tuning Tuning considerations
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Curves from Dyno Need to know where you are starting! Force/Absolute Velocity curves Multiple velocities
Curves for each shock Tuned/adjusted to match
Curves for range of adjustments
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Fit Check on Vehicle Make sure design is correct! Correct travels Shock and spring
Jounce bumper engagement No binding or interferences
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Base Vehicle Testing Basic motions and transistions Basic ride motions Low frequency input (Sprung resonance) Bumps (Unsprung resonance) Extreme travel events
Transistions Braking, turn-in, acceleration
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Advanced Tuning More than basic tuning Track testing Transition maneuvers 7-post testing
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Tuning Considerations A damper is a VELOCITY sensitive device Force is a function of velocity, not displacement
Can be used as a dynamic spring Generate force when in motion Passive at steady state
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Tuning Considerations Velocity for transients typically below 2 in/sec
Turn-in Braking Acceleration Aero control
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Tuning Considerations Velocities for bumps typically 2-10 in/sec Velocities for extreme travel events above 10 in/sec
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Tuning Guides
This document is property of Kaz Technologies Not authorized for use by outside organizations
Tuning Guides There are many ways to use dampers
Dampen resonant frequencies Dynamic spring Hold down device Jack up device
There are many correct answers
This document is property of Kaz Technologies. Not authorized for use by outside organizations
This document is property of Kaz Technologies. Not authorized for use by outside organizations
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Care & Feeding
This document is property of Kaz Technologies Not authorized for use by outside organizations
Damper Care & Feeding Main objective is repeatability and durability
Tune adjusters so forces match Check gas pressure often Dyno test at least once a year Look for oil leakage Check for rod and seal damage
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Professional Damper Care How race teams do it Damper settings checked with each setup and set down Gas pressure checked each day Dampers curved before race Dampers rebuilt and forces matched after each race
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Questions?
This document is property of Kaz Technologies Not authorized for use by outside organizations
Advance Tools Damper testing 7-post testing
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Testing Multi-Frequency Testing Variable frequency and amplitude sine sweep Actual vehicle data Actual data Low frequency (sprung resonance) data High frequency (unsprung resonance) data
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Testing Roehrig EMA Dyno Electro-magnetic actuator Triangle, sine, square and composite waves Can play back shock displacement data from track data
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Damper Testing Multiple Input Test
Traditional peak velocity sine wave Track data file Low frequency track data High frequency track data Sine sweep Based on track data
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Multiple Input Test
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Multiple Input Test Peak Velocity
Track Data
Low Freq Track Data
High Freq Track Data
Sine Sweep Based on Track Data
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Kaz Tech Shock Testing Tools
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Kaz Tech Shock Testing Tools EMA Complex Drive File Generator Graphical Plotting & Analysis Tool Results Workbook Analysis Metrics
This document is property of Kaz Technologies. Not authorized for use by outside organizations
7-Post Testing
This document is property of Kaz Technologies Not authorized for use by outside organizations
What is 7-Post Testing? Simulates track input in a lab test Uses data from the race track to reproduce input to the car Track input to the tires Aero and banking loads to the body
Sine sweep input for frequency testing
This document is property of Kaz Technologies. Not authorized for use by outside organizations
What is a 7-post? The 7-post shaker is an engineering system
Exerts forces on the vehicle Records the forces that the vehicle puts back into the system Records various system responses
A 7-post consists of 7 hydraulic actuators 4 actuators with wheel pans input road 3 actuators input aero loads
This document is property of Kaz Technologies. Not authorized for use by outside organizations
What is a 7-post? Four wheel pan actuators
Input simulated road displacement into the vehicle Displacement driven Same displacement throughout the test
Load and acceleration measured at the wheel pans or platens Typically driven up to 50 Hz
Three down force actuators Load driven
Same load throughout the test (except when active aero is in use)
Allows for vehicle displacement, acceleration, and velocities to be a variable Typically driven up to 1 Hz
This document is property of Kaz Technologies. Not authorized for use by outside organizations
This document is property of Kaz Technologies. Not authorized for use by outside organizations
7-Post Testing 7-Post Drive Inputs
Sine sweep Track data based drive file Discreet event Low frequency from track data
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Why 7-Post Testing? Solution to limited track tests Shock development Suspension set-ups
Measure response in the lab you cannot measure on the track Tire grip Aero loading
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Why 7-post Testing? The 7-post will not give you the magic set of shocks or setup! It will give you: The knowledge of how each component affects the whole system The magnitude of each effect An understanding on the cause and effect The information to make educated decisions at the racetrack This document is property of Kaz Technologies. Not authorized for use by outside organizations
7-Post Testing is a Cycle
Track data gathering Drive file development Test planning Drive file evaluation Test execution Data analysis Application at the racetrack
This document is property of Kaz Technologies. Not authorized for use by outside organizations
7-Post Testing Analysis Required elements of analysis
Tire force variation (mechanical grip) Body control Wheel control Aerodynamic downforce Driver comfort
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Kaz Tech 7-Post Testing GM Racing 7-Post Testing
1977: First NASCAR 7-post test Numerous race wins Developed GM 7-Post Test Method Test methods Data analysis routines Data presentation Results taken directly to racetrack Continuous test development Data analysis & reporting Testing Methodology On-going assessment of 7-Post state-of-the-art
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Kaz Tech 7-Post Tools
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Kaz Tech 7-Post Tools
Data Processing Results Workbook Customized Team Results and Reports Graphical Plotting & Analysis Tool Team Console Drive File Quality 7-Post Performance Load Transformation This document is property of Kaz Technologies. Not authorized for use by outside organizations
Questions?
This document is property of Kaz Technologies Not authorized for use by outside organizations
The Last Word Records When enough is enough! References
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Records If you don’t keep records, you start from scratch every time you start the car! You can only improve if you know where you are starting from!
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Records
Setup Sheets Run Log Driver Evaluation Sheets Race/Test Summary Track Data Files
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Setup Sheets Baseline or starting setup Shop setup Final setup at track
Set down setup at end of each session Final set down set up at end of each test
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Event Information
Chassis Information Packer Gap
Aero Information Gearbox Information Session Tabs
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Run Log EXCEL File with Worksheets for:
Race/Test Summary Worksheet for each session Data Analysis Summary Tire Summary Race Log
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Opening Page: Event Summary
Tabs for: -Summary -Data Analysis -Tire Sheet -Session Sheets -Race Log
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Session Information
Tire Data Tire Info
Driver Comments
Changes
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Tire Sheet
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Race Information
Lap Times & Leader Info
Driver Comments Tire Data
This document is property of Kaz Technologies. Not authorized for use by outside organizations
This document is property of Kaz Technologies. Not authorized for use by outside organizations
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Event Information Weekend Summary Race Summary Driver De-Briefs
Next Race
Session Lap Times
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Track Data Files
This document is property of Kaz Technologies. Not authorized for use by outside organizations
When Enough is Enough
This document is property of Kaz Technologies Not authorized for use by outside organizations
When Enough is Enough Patrick Head AT&T Williams F1 Director of Engineering It is not the team that achieves the most horsepower or downforce that wins the race. It is the team with the best compromise of all the systems on that day that wins.
This document is property of Kaz Technologies. Not authorized for use by outside organizations
When Enough is Enough What does this mean? EVERYTHING is important! No one system is more important that another
EVERYTING is a compromise! You don’t have to have it all perfect to win In fact, you won’t get all of it right!
The best TOTAL package will win
This document is property of Kaz Technologies. Not authorized for use by outside organizations
References
This document is property of Kaz Technologies Not authorized for use by outside organizations
References Books by Carroll Smith
Tune to Win Drive to Win Prepare to Win Engineer to Win Nuts, Bolts, Fasteners and Plumbing Handbook Engineer In Your Pocket
This document is property of Kaz Technologies. Not authorized for use by outside organizations
References Books Race Car Vehicle Dynamics William F. Milliken and Douglas L. Milliken
Fundamentals of Vehicle Dynamics Thomas D. Gillespie
Shock Absorber Handbook John C. Dixon
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Kaz Technologies http://www.kaztechnologies.com Information about Kaz Technologies
Product information FSAE damper drawings, CAD and damping info Tech Tips Seminar downloads
e-Store for FSAE products
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Kaz Technologies Questions? [email protected] Topics to Discuss? http://www.facebook.com/Kaz.Technologies Start a discussion!
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Kaz Technologies Jim Kasprzak [email protected] 248855-3355 Tom Jaworski [email protected] 734-536-3218 Jess Youngblood [email protected]
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Kaz Technologies
http://www.facebook.com/Kaz.Tech nologies
This document is property of Kaz Technologies. Not authorized for use by outside organizations
Thanks!
This document is property of Kaz Technologies. Not authorized for use by outside organizations