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UCSD FSAE Engine Dynamometer

Chinaar Desai, Cassandra Moreno, Luke Bockman, Justin Moreno

Sponsored by: Triton Racing - UC San Diego’s Formula SAE Team

Overview

Triton Racing is an engineering project team that designs, builds, and tests Formula-style race cars for an annual international competition. To continue producing cutting-edge race cars, measuring and optimizing engine performance is a major priority for the team. An engine dynamometer (dyno) enables the team to do just this. This dyno test bed is designed and built by our team for the MAE 156B Spring 2017 quarter.

Intended as a foundational project, the current design of the dyno allows for simply calculating engine horsepower as a function of torque and RPM, but also monitoring fluid temperature in critical flow paths. In the future, Triton Racing has been set up with the ability to expand the dyno capabilities to monitor more parameters like air/fuel ratio, pressure, and cylinder head temperatures.

Custom Frame Design

Water System Design

Summary of Hardware Performance

Testing section here (to be completed later)

Major Dyno Components

Frame

5 welded, steel subframes bolted together
Movable and relatively lightweight
Powder coated for external environment
Easily adjustable with the use of shims for manufacturing uncertainties�

Water Brake

Modeled on a Stuska Dyno water brake
Entirely machined in-house
200 kW capacity
Type 2 anodized aluminum�

Water System

Loads water brake, circulates water, and provides cooling
Includes a circulator pump, radiator, pump filter, reservoir, and flex PVC tubing�

Sensors and DAQ

DAQ: National Instruments’ myRIO
Torque: analog S-type Load Cell
RPM: digital Hall-effect speed sensor
Temperature: 4 waterproof, 1-wire, digital thermistors
LabVIEW virtual interface with active monitoring and data storage

Water Brake Design

Torque capacity equation:

- Capable of absorbing 200 kW

- Capable of rotational speeds up

to 7000 RPM

- Machined from 6061-T6

Aluminum and 316 Stainless steel

Anodized for corrosion resistance

Sensors & Data Acquisition

myRIO DAQ allows for expandable capabilities
Entire system powered by 5V
Data transfer over Wifi or USB Connection

Future Improvements

Electronic control of water brake’s inlet valve

More repeatable testing and realistic conditions

Expand sensor portfolio to monitor more parameters (air/fuel ratio, pressure, etc.)
Compare results to a professional test run
Consider compensation factors for air temperature, humidity, etc.

Safety and Impact on Society

Safety: Driveshaft rotates at 6000 rpm (high rotational kinetic energy and inertia)

Whipping prevented by 6.35mm thick steel collar
Operator protected by perforated sheet metal and location away from plane of rotation

Pollution: 5 gallons of fuel used per dyno run
Noise: 60-70 dB level requires ear protection
Economic: build price is $2300
Infrastructure: a dyno gives the best experience for FSAE engineers and teams

Acknowledgements

The team would like to thank:

Professors: Dr. Tustaniwskyj and Dr. Silberman
TA and MAE Staff: P. Franco, T. Chalfant, I. Richardson, S. Roberts, and G. Specht
Project Sponsors: R. Shanahan and Triton Racing
Industry Sponsors: I. Foldvari (NI), B. Schlossnagel (Schlossnagel Racing), Action Powder Coating, and Anocote Metal Finishing

Fig. 1: Final SolidWorks CAD of Engine Dyno

References

[1] “Automotive Systems” Sweet Haven Publishing Services. Nov. 2009. Web. April. 2017. <http://www.waybuilder.net/sweethaven/MechTech/Automotive01/?unNum=1&lesNum=3&modNum=1>

[2] “Savings Project: Lower Water Heating Temperature” Energy.gov. Web. May. 2017. <https://energy.gov/energysaver/projects/savings-project-lower-water-heating-temperature>

[3] N. N. Narayan Rao, “The Basic Theory of Hydraulic Dynamometers and Retarders” Central Mechanical Engineering Research Institute, India

[4] Kyoung Suk Park et al, “Thermal Flow Analysis of Vehicle Engine Cooling System” KSME International Journal, Vol, 16 No. 7. pp. 975~ 985, 2002

[5] Matthew Carl et al, “THE THEORETICAL AND EXPERIMENTAL INVESTIGATION OF THE HEAT TRANSFER PROCESS OF AN AUTOMOBILE RADIATOR”, 2012 ASEE Gulf Southwest Annual Conference

[6] Incropera, Frank P. Introduction to Heat Transfer. 5th ed. Hobokenm NJ: Wiley, 2007. Print.

[7 Moran, Michael J, and Howard N. Shapiro. Fundamentals of Engineering Thermodynamics. Hoboken, N.J: Wiley, 2010.

Fig. 2: Subframe Breakdown

Fig. 4: Anodized Water Brake

Fig. 6: Exploded View of Water Brake Design

Fig. 7: MATLAB Thermodynamic Simulation Results

Fig. 8: Water Flow Circuit

Fig. 9: Data Acquisition Circuit

Fig. 10: LabVIEW User Interface

Built-in accelerometer monitors vibration of entire system
Small programming learning curve (LabVIEW fundamentals are already taught)
Store data for further analysis in MATLAB

Fig. 11: Torque and Hp Curves vs. RPM From Professional Dyno Runs

Ideal results would mimic curve trend from professional dyno tests in the past

Fig. 5: Detailed Section View of Water Brake Assembly

Fig. 3: FEA Results on Base and Driveline Subframe

Easy removal of subframes for maintenance
Strong and lightweight (about 90 kg)
For multi-engine use (currently designed for a Yamaha FZ6R)

SolidWorks FEA performed

2 Cases: Apply load at joints

75 N*m engine torque output and reaction torque of water brake
Instances of misuse (ie. due to a person climbing the system: 1300 N)

Results: 1 mm deflection and F.S. = 4

- Closed loop water system used to load water brake

by operator-controlled load valve

- Max engine power occurs at 9000 rpm; results in

63.38 kW (85 hp) (Fig.11)

- Thermodynamic simulation to determine required

cooling of system (Fig.7)

- With radiator and 10 gallon reservoir, water

temperature reaches up to 50 ℃

- Sufficient cooling provided; no cavitation

- Total head loss through water system is 3.05m

- Max flow rate needed to load water brake is

9.46E-4 m³/s (15 gpm)