BRAKE DYNAMOMETER
DEVELOPMENT FOR DREXEL
UNIVERSITY FSAE RACE TEAM
MEM-01
Dr. Tein-Min Tan
Frank DiMento
Anthony Tofani
Alfredo Vitale
John Henry
What is a Brake Dynamometer?


A system used to duplicate track braking
scenarios in order to analyze a brake system
design before the components are implemented
on a race vehicle.
This piece of machinery can be utilized by all
Drexel University race teams, including Formula
SAE, Sonic Cricket, and Mini Baja.
Benefits of a Dynamometer





Prototype costs lowered
Flexible testing schedule
No risk to driver or vehicle
Quantified performance data
Example:

2005 Sinusoidal Rotor Design
Previous Work



2005 FSAE Brake Team Designed a Brake
Dynamometer that was not completed.
2006 FSAE Brake Team added a power
controller to obtain necessary three phase
power.
The dynamometer has never ran properly and
lacks a data acquisition system.
Current Drexel Dynamometer
Problem Statement


Drexel SAE lacks the ability to perform in-house
testing on its braking system design; Prototypes must
be complete systems tested on completed car.
Data from test runs of actual system components
would be useful for design, including:





Braking horsepower
Thermal loads
Rotor and pad coefficient of friction
Actual hydraulic operating pressure
Drexel SAE has a dynamometer that is incomplete and
not operational.
Available Dynamometers

Extremely expensive

Requires large work area

Hard to relocate
Methods of Solution
Constraints and Challenges
Existing Parts

We must integrate existing dyno parts.
Cost

Funding must be allocated to produce product.
Time

Must be completed within the requirements of Senior
Design.
Safety

Must be safe for operator and environment.
Adaptability

Able to test a wide variety of component designs.
Initial Design
Old Rig Orientation





Lower Center of Mass
Effective Tensioning
Contained Hydraulic
Actuator
Single Chain
Secured/Cushioned Feet
New Rig Orientation
Hydraulic Actuator
Dynamometer Systems
Dynamometer Systems
Calculations



Determine correct sprocket sizes for desired
flywheel, motor, and rotor speeds
Complete Finite Element Analysis of Frame
Calibrate LabView based on comparison of
measured data and theoretical values
Line Pressure
 Coefficient of Friction
 Braking Torque and HP

Manufacturability/Feasibility

Team will require outside resources:
Machining operations
 Tools



Single-unit production does not require massproduction methods
Team covers all necessary skills, including
welding.
Calibration and Testing


Dynamometer will need to be calibrated and tested to
ensure accuracy
As-measured data will be compared to hand-calculated
values and data published by component manufacturers
(Wilwood, etc.)




Coefficient of Friction
Line Pressure
Net System HP
Calibration to be done by tuning values in LabView
simulation
Environmental & Societal Impacts

Brake Fluid Containment


System pressures will be kept within the limits
recommended by component manufacturers to
prevent leakage.
Operator Safety
Rotating components will spin in excess of 3000
RPM and will be well balanced to prevent vibration
and fatigue. Safety guards will be installed to protect
operator and area workers.
 We will measure noise levels during machine
operation to verify that hearing damage will not be a
concern.

Project Deliverables

An operating Brake Dynamometer System that
will be used to determine the following data:
System Braking Horsepower
 Operating and Maximum Temperatures and
Pressures
 Pad-Rotor Coefficient of Friction


Documentation that includes:
Standard Operating Procedures
 Maintenance Instructions and Schedule

Timeline
Economic Analysis
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
2007 FSAE Brake Dyno Budget
Component
Cost
Company
DAQ CARD
$219.25
National Instruments
SQUARE TUBING
$215.44
McMaster Carr
FASTENERS
$32.50
Home Depot
GUARDS
$80.00
McMaster Carr
TEMP SENSOR
$150.00
Metris Instruments
PRESS SENSOR
$162.50
APG Automation
LOAD CELL
$327.50
Omega Engineering
OPTICAL ENCODER
$0.00
Previously Purchased
MACHINING
$300.00 Drexel / Cygnet Manufacturing
FORCE DEVICE MATERIAL
$132.00
Hadco Aluminum Supply
FORCE DEVICE ACTUATOR
$259.00
Firgelli Automations
FORCE DEVICE POWER
$57.50
Power Supply Direct
COMPUTER
$459.00
Dell
RUBBER FEET
$90.00
McMaster Carr
SPROCKETS
$60.55
Martin Sprocket
Project Overall Cost
$2,545.24
Cost Effectiveness

The current dynamometer has already exhausted the
following funding:




$500 – MEM Department Donation to Install Power Supply
$350 – ABB Power Controller Donation
$839 – DR-06 Design Team Dyno Development Cost
$1400 – DR-05 Design Team Dyno Development Cost
Thus $3,089 has been ineffectively spent for a machine
that is inoperable to date. Granting our funding request
will allow us to validate previous funding by creating a
working device for future SAE teams to use.
Conclusions




A Brake Dynamometer is a valuable tool in
brake system development.
We will deliver a complete and operational brake
dynamometer within our projected timeline.
Our dynamometer will be safe for operators and
other area workers.
We will include documentation explaining
operation and maintenance so that the dyno may
be used for years to come.
Questions?