FSAE FLOW TESTING DEVICE
PRODUCT DESIGN SPECIFICATION REPORT
WINTER 2012
Group members
Adam Barka
Jasper Wong
Keith Lundquist
Long Dang
Vu Nguyen
Portland State University Advisor
Dr. ChienWern
Industry Advisor
Evan Waymire
1
Table of Contents
Introduction...... 1
Purpose of this PDS Document...... 2
Mission Statement...... 2
Project Plan...... 3
Customer Identification...... 4
Customer Feedback/Interviews...... 4
Product Design Specification...... 5
House of Quality...... 8
Technical Risk Management...... 9
Conclusion...... 11
Appendix...... 12
Introduction
Each year, the Society of Automotive Engineers (SAE) invites colleges from around the world to participate in their Formula SAE series competition. This competition challenges students from each school to design, build, and race an open-wheeled formula style race car. Portland State is represented in this series by the Viking Motorsports (VMS) student group.
In order to encourage teams to focus on design and optimization rather than on generating raw power, the SAE has imposed a series of regulations on the powertrain subsystem of the race car. The most notable regulation is that all of the air supplied to the car’s engine must go through a 20 mm restrictor, which severely limits the output power of the engine. To overcome this, VMS must be able to accurately measure the mass flow of any customized component (see Appendix A) at a standard pressure in order to reduce parasitic losses to the engine. In addition, the team must measure the discharge or flow coefficient of the cylinder intake and exhaust valves, as well as of the butterfly valve on the throttle. These values are necessary for the team to utilize 1-D simulation software to improve their design. Currently, VMS has no method to test for these values.
In order to flow test their components, the powertrain group could purchase a device known as a flow bench. A typical flow bench uses a pump to move air through a device under test (DUT) and then through a calibrated obstruction flow meter at a standard test pressure, which is measured upstream of the flow meter. The pressure drop across the obstruction is a known function of the volume flow rate through the meter. The mass flow rate through the DUT, also known as the flow coefficient of the DUT, is calculated from the volume flow across the meter and from temperature/pressure measurements at the DUT. Figure 1 shows a typical flow bench operating under a negative pressure differential (relative to atmospheric). A flow bench would reverse the flow by creating a positive pressure differential relative to atmospheric.
Figure 1.Simple flow bench.P1 is the test pressure; the difference P2-P1 is measured to produce mass flow rate.
There are many flow benches available for purchase, but all share similar limitations. Foremost is cost. Commercial flow benches with enough air flow capacity to accurately test VMS powertrain components cost anywhere from $5,000 to $15,000. In addition, commercial devices would require VMS to build customized mounts to accommodate the restrictor, intake manifold, and exhaust. Finally, commercial flow benches do not easily allow for future improvements or modifications. VMS has constantly changing needs, and so must be able to modify the flow bench.
The other option is to buy a home build kit. These “do it yourself” (DIY) kits include key components and/or detailed plans with which to build a flow bench. The kit is a more affordable option. However, the measurements provided by flowbenches built from DIY kits have unspecified uncertainty.In addition, they generally require manual calculation to attain the flow rate, which leads to low treatment turnover. Finally, DIY options would also need customized test fixtures to mount all components.
Purpose of this PDS Document
The purpose of this document is to outline the customer’s requirements andthe team’s plan to meet those requirements. The Product Design Specification document must clearly define the design criteria, metrics, targets,and priorities to meet customer requirement. Some core criteria include cost, capacity, accuracy, and service life. A detailed list of criteria is provided in the Product Design Specification section. The team and our customers will agree on this document as a principal guideline for product delivery.
Mission Statement
This team is challenged to design and build a device capable of measuring the flow coefficients for the intake, exhaust, and throttle valves of a formula SAE racecar at various open positions, and to measure the mass flow through the racecar’s intake manifold and exhaust ductwork. The device will measure these values at a standard test pressure of 28 inH20 with 95% measurement repeatability. The completed project, consisting of a working prototype, testing results, detailed drawings, bill of material, and detailed reports, will be presented in June 2012. If successful, the project would help the VMS team to validate and improve their designs.
Project Plan
The dates inTable 1 are critical milestones for the project. A Gantt chart is provided in Appendix B and will be considered as a living document. Dates other than due dates are subjected to change, dependent on the project requirements.
Table 1.Project Milestones.The team will work on the Tasks between the Start and Finish dates. Due dates reflect times when the tasks must be delivered to the customers.
Task / Start / Finish / DueProject Planning / Jan 9 / Jan 13 / N/A
PDS Report / Jan 9 / Jan 29 / Jan 30
PDS Report Presentation / Jan 31 / Feb 3 / Feb 6
External and Internal Search / Jan 19 / Feb 5 / N/A
Concept Evaluation / Feb 6 / Feb 13 / N/A
Detail Design / Feb 13 / Mar 5 / N/A
Progress Report / Feb 7 / Mar 11 / Mar 12
Progress Report Presentation / Mar 1 / Mar 4 / Mar 5
Prototype and Test / Mar 24 / May 23 / N/A
Final Report / Apr 24 / May 25 / N/A
Release Design to Customer / May 28
Customer Identification
For this project, two categories of customer exist: external customers and internal customers. The first of the external customers is Viking Motorsports, who is the end user of the testing device, and therefore provides the key performance, ergonomics, and size criteria.BesidesVMS, industry adviser EvanWaymire and faculty member Dr. Gerald Recktenwald arealso the team’s external customers, as they provide the cost and various performance parameters. VMS’s use of the testing devicewill be scored by a team of judges at the FSAE competition, therefore the competition judges are another customer for this project.
In addition there are three internal customerswho must be taken into account. The first two of these areDr.FaryarEtesami and theMaseeh College of Engineering and Computer Science, who provide the documentation requirements.Likewise, Portland State University is a key customer, because the project must adhere to the school’s requirements for graduation.
Customer Feedback/Interviews
Direct feedback from the VMS powertrain team and Evan Waymire has been an integral part of determining the design specifications for this project. The concept for the project was first developed by RobertMelchione, who leads the VMS powertrain team. Rob proposed the idea during the summer of 2011, as a way to make flow testing for the car an integral part of the design and validation process. Until now, VMS has not performed flow testing on its engine components. During the summer of 2011, preliminary meetings with Evanprovided a basic outline for what the design parameters would be. During that time, the mechanical engineering department head, Dr.Recktenwald, held a meeting, during which he provided funding information and advice for performing analysis and finding resources for this project.
The competition judges are also key customers, butwe cannot interview them in person. Given this, we have reviewed the FSAE rules (Appendix C)and feedback from the 2011 design competition in order to extrapolate the design judge’s requirements for this project.
Product Design Specifications (PDS)
Table 2 is a representation ofeach customer’s design requirements, as well as applicable parameters. These include the priority level of each, which are rated by the customer as either high, medium, or low with three, two, or one dot, respectively,as well as the associated metrics and targets and how that target will be verified. Some targets may change,with the customer’s approval,based on detailed analysis of the system.
Table 2. Design Specifications
Priority / Requirement / Customer / Metric / Target / Target Basis / VerificationPerformance
/ Repeatability of measurements / VMS / % difference / (+/-) 5 / Customer feedback / Testing
/ Flow Rate/Pressure Capacity / VMS / cfm,
inH2O / ≥160,
28 / Group decision / Prototyping
/ Test intake, throttle, muffler, valves / VMS / Yes/No / Yes / Customer feedback / Design
/ Waiting time to get steady value / VMS / Min / 15 / Customer feedback / Testing
Safety
/ Emergency stop / VMS / Yes/No / Yes / Customer feedback / Design
/ Warning labels / VMS / Yes/No / Yes / Customer feedback / Design
/ Ergonomics safety / VMS / Yes/No / Yes / Customer feedback / Design
Environment
/ Low noise / VMS / dBA / 95 / Customer feedback / Design
Ergonomics
/ Easily acessible / VMS / Yes/No / Yes / Customer feedback / Design
/ Number of operators / VMS / people / 1 / Customer feedback / Testing
/ Training time / VMS / hours / 5 / Group decision / Testing
Size
/ Footprint / VMS / ft x ft / 6 x 4 / Customer feedback / Design
Maintenance
/ Easy to inspect and replace parts / VMS / Yes/No / Yes / Customer feedback / Design
/ Frequency of required maintenance / VMS / months / 6 / Customer feedback / Design
Installation
/ Time to assemble and disassemble / VMS / hours / 4 / Customer feedback / Testing
/ Time to setup / VMS / min / 20 / Customer feedback / Testing
/ Required specialized power source / VMS / Yes/No / No / Customer feedback / Design
Cost
/ Total cost / PSU / USD / 3500 / Customer feedback / Bill of materials
Documentation
/ PDS / PSU / Deadline / 01/30/2012 / Course requirement / Receipt
/ Progress report / PSU / Deadline / 03/05/2012 / Course requirement / Receipt
/ Final report / PSU / Deadline / 05/28/2012 / Course requirement / Receipt
/ Instruction / VMS / Yes/No / Yes / Customer feedback / Hard copy
Applicable codes and standards
/ Meetindustry standards / VMS / Yes/No / Yes / Customer feedback / Study of regulations
Material
/ Reasonable price / Team / Yes/No / Yes / Customer feedback / Bill of material
Quantity
/ Number of devices / VMS / unit / 1 / Customer feedback / Final product
Life in service
/ Continued operation with approriate mainternace / VMS / years / 5 / Customer feedback / Design
Manufacturing facility
/ Design parts for manufacturability / Team / Yes/No / Yes / Group decision / Design
House of Quality
The House of Quality (Table 3) relates the influence of the project requirements to engineering criteria. Each cell within table has a '' symbol marker to relate the influence of the project requirement to engineering criteria. The symbol ranges from '' high influence, to '' little influence, if the cell is left blank then no influence.Also the importance of the requirements is listed from a scale of one to ten, with the total score adding to ten.
Table 3. House of Quality
REQUIREMENT / IMPORTANCE / CUSTOMER / ENGINEERING CRITERIA / COMPETITIONCost / Weight / Flow rate / Noise level / Basic 2.0 / SF-600
USD / lb / cfm / dBA / Flow Performance / SuperFlow
PERFORMANCE / 3
Accurately Measure Flow / 1 / VMS / / / / / /
Capacity / 1 / / / / / /
Test Intake, Throttle, Muffler, and Valves / 1 / / / / / /
SAFETY / 2
Emergency Stop / 2 / VMS / / / /
ENVIRONMENT & ERGONOMICS / 1
Low Noise / 0.5 / OSHA / / / / / /
Training Required / 0.5 / VMS / / / /
MAINTENANCE / 1
Easy to Inspect and Replace Parts / 1 / VMS / / / / /
COST / 3
Less Expensive than Commercial Options / 3 / ME / / / /
COMPETITION
Basic 2.0 (Flow Performance) / 1600 / 100 / 600 / 101
SF-600 (SuperFlow) / 9000 / 400 / 600 / > 85
TARGET / 3500 / 200 / 160 / 95
Verification / BOM / Inspect / Test / Test
Technical Risk Management
To ensure the success of this project, we have identified the probable risks and their associated consequences (Table 4). Depending on the probability of the risk event occurring and its severity, we developed an in-depth mitigation and monitoring plan for high level risks, summarized in Table 5.
Table 4.Risk Identification and Assessment
RISK / ASSESSMENT / MITIGATION / MONITORINGODDS OF EVENT OCCURRING / CONSEQUENCES / LEVEL OF RISK
Project Exceeds Budget / Possible / Severe / High / Necessary / Necessary
Not Serviceable / Unlikely / Severe / Medium / Necessary / Necessary
Design too Complicated to Fabricate / Possible / Severe / High / Necessary / Necessary
Team Alignment and Communication / Unlikely / Negligible / Low / Necessary / Unnecessary
Not Meeting Deadline / Possible / Severe / High / Necessary / Necessary
Change in Budget / Possible / Severe / High / Necessary / Unnecessary
Machine Does Not Meet Requirements / Possible / Severe / High / Unnecessary / Unnecessary
Injury to Operator / Possible / Catastrophic / High / Necessary / Necessary
ould you please write a paragraph introducing the table and explaing what it contains. be made and targets and how tat target i
Table 5. Risk Mitigation and Monitoring
Risk: / Injury to Operator / Mitigation: / Design for acoustics will be limited to maximum 95dBA, and equipment operator will wear ear plugs during equipment use. Kill switch will be included for immediate shut off of equipment.Degree of Risk:
HIGH
Monitoring: / Acoustic levels will be tracked with dBA meter on equipment periodically (monthly/quarterly).
Risk: / Not Meeting Deadline / Mitigation: / Communication between team members and accountability for individual members to complete tasks.
Degree of Risk:
HIGH / Monitoring: / Weekly meetings with academic advisor, weekly work parties, online communication, and Gantt chart for project tracking.
Risk: / Design is Difficult to Manufacture / Mitigation: / Design for performance and manufacturability
Degree of Risk:
HIGH / Monitoring: / Track all design changes on personal team server and have design review meetings.
Risk: / Project Exceeds Budget / Mitigation: / Use reasonable priced components during design of flow bench system. Validate component choice with uncertainty analysis.
Degree of Risk:
HIGH / Monitoring: / Create a B.O.M with different options for different price levels that determine which to build upon budget received
Conclusion
This document addresses the key specifications and issues of designing and manufacturing a flow test bench for the Viking Motorsports Formula SAE team. Key areas of difficulty or interest stem from designing to a wide and unique operating range in terms of pressure, flow rates, part mounting, and data acquisition.
Developing a custom flow bench will greatly improve the quality of the VMS program by allowing for the team to validate their designs to a far greater degree than in the past. In addition, making the device available to the students at all times will provide future students the ability to gain significant experience in part testing and increase understanding of how to incorporate part testing into the design process. The availability of the device, when combined with detailed documentation, will also give future VMS members the opportunity to improve on the device’s functionality, thus creating long-term potential for improving the car. In the end, this team believes that the device will give VMS a strong competitive advantage in competition, since very few of the other FSAE teams have access to flow testing at this accuracy level.
Appendix A: 2011 VMS powertrain components
This section includes the components which VMS needs to test for mass flow rate, or flow coefficient. The kind of information needed and the specific mounting requirements of each component are detailed.
A1. Intake Manifold
This is the device which disperses the air which comes through the restrictor to the individual cylinders. The mass flow rate through each runner is needed to determine if all 4 cylinders are receiving the same amount of air. A custom test fixture needs to include a bracket with all four 25 mm, with three plugs. Flow only needs to me measured at a negative pressure differentail.
Figure A1. Intake manifold
A2. Throttle/Restrictor
This piece contains both the throttle butterfly valve and so VMS needs flow coeficients for the valve, and mass flow at wide open throttle. The custom test fixture would need a 25 mm adapotor with properly placed holes for the bolts, as well as a mechanism for controling the degree of opeing in the throttle valve. Flow only needs to me measured at a negative pressure differentail.
Figure A2. Throttle body
A3. Exhaust
After combustion, the air in the engine is expelled to the atmosphere through the exhaust. VMS needs to know the pressure loss in this ductwork. The exaust will be mounted in a similar fashion to the intake manafold. This part needs a positive pressure differential.
Figure A3. Exhaust system
A4. Cylinder Head
The cylinder head contains the valves which regulate the intake and exhaust flow through each cylinder. Reliable flow confinements are needed for each valve for 1-D engine simulation software. The head needs a custom 67 mm bore adaptor and a device for controlling the valve lift. The cylinder head needs to be measured under both negative and positive pressure differential.
Figure A4. Engine head (Honda CBR 600cc F4i)
APPENDIX B
Detailed Gantt chart