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Formula SAE 04/27/2007 AET Team Members Andrew Tyler Shawn Albertson Paul Vandevender Adam Pompa Matt Davied Jake Speilbusch Introduction PSU Racing is embarking on its inaugural FSAE competition. Our team of six members was formed August 2006 and has been diligently working to meet the goals set forth by the FSAE Rules committee to compete in the west competition June 2007. Objective The objective for the 2007 PSU racing team is to complete the build of the vehicle and finish all dynamic events at the west competition as well as laying a foundation to ensure success and continual improvement by the team at future events. Manufacturability • Our vehicle design utilizes commercially available products except for the frame, uprights, fuel tank and drivers control components. This ensures replacement parts availability if needed, as well as properly engineered parts for the application. Reliability • Designing our vehicle to use commercially available products minimizes design risk by utilizing proven designs to meet the criteria of the event. Our fuel injection system, E.C.U. and drive-train were all assembled from commercially available components designed to meet our application. Cost Efffectiveness • As stated above, we are a first year team and have an initial budget of $15,000. We have chosen designs that meet the criteria set forth by the rules committee and satisfy our goal of producing a low-cost vehicle. This approach will also help us to meet the goal of building a vehicle under $15,000. Conceptual Designs The first conceptual design utilized side pods housing two radiators and electronic equipment. The second conceptual design utilized a single rear mounted radiator with no side pods. After carefully analyzing cost and manufacturing time projections, the second conceptual design was chosen to be produced. Two Basic Body Designs • Side Louver Design – Consists of bullet type car but with side louvers. – Space for radiator and electronics. – Added Weight AET Two Basic Body Designs • Bullet design – Consists of a straight through body with no wings or side louvers. – Streamline design. AET Frame • The vehicle utilizes a tubular space frame that is composed of T.I.G. (Tungsten Inert Gas) welded 4130 chrome-moly steel tubing. • The cockpit was designed to give the driver room for entering and exiting the car, as well as provide room for steering and shifting motion of various sized drivers. • The front portion of the frame provides ample room for drivers with different leg lengths. • The rear portion of the frame was designed using the engine as a rigid component. • A-arm and suspension mounting points of the frame were analyzed using Pro-Mechanica and designed to have a safety factor of 3. • Throughout the frame, the members have been triangulated to increase rigidity and reliability. Impact Attenuator • The guidelines set forth by the SAE were met by utilizing proprietary soy-based foam from Pittsburg State University’s organic polymer research center. • The foam, through finite element analysis as well as destructive testing, showed an average deceleration of 9.17g. Substantially lower than the 20g maximum. • The foam was chosen because of superior performance to other materials as well as cost. The foam material used in the attenuator was purchased for $3.24, a cost that is well below other material with similar properties. Upright Assembly • Both the front and rear uprights are green sand castings of 356 aluminum alloy with a T6 heat treatment. • The uprights were analyzed using Pro-Mechanica and designed to have a safety factor of 3. • Using pre-manufactured hubs and bearings from commercially available vehicles allows the owner to purchase replacement parts from various suppliers. • Each upright assembly includes the same hub and bearings, this simplifies the manufacturing process. Suspension • The suspension utilizes double a-arms in both the front and rear. • The a-arms are comprised of ¾” 4130 chrome-moly steel alloy round tubing. The material allows our safety factor of 3 to be met. • A single vertical coil-over shock with push rod activation is used on each corner of the vehicle for the dampening system. • The a-arms attach to the uprights and frame using 3/8” I.D. heim joints. The heim joints are installed in double shear to ensure a safety factor of 3. Engine and Transmission • 600 cc Honda Sport Bike Engine – Fuel Injected • 6 speed Honda Transmission – Linked to mechanical ratchet shifter Engine Control Unit • An engine control unit (ecu) manufactured by Dynojet research is used to control the fuel injection system. • This system uses the stock ecu in conjunction with the unit from Dynojet. • This allows use of the factory spark curve and only change the fuel map which is most effected by the restricted intake. • The unit costs substantially less than a stand alone ecu. Restrictive Intake • An intake was manufactured using widely available polyvinylchloride (pvc) piping. • The 20mm restrictor was manufactured out of aluminum billet. • The intake system uses 2” pvc to connect the restrictor to the factory air box which contains one set of the factory injectors. Drive-Train • A Torsen differential was selected and modified to accept a 38 tooth 525 sprocket input. • This unit will provide traction to each rear wheel proportionally, but allow one side to free wheel during turns to prevent wheel hop. • Power is transmitted from the differential via splined constant velocity shafts which are then splined to commonly available wheel hubs. • The constant velocity shafts used are from a commercially available vehicle and cost effective to purchase rather than manufacture. Ergonomics • Drivers comfort was a major concern during design. • This matter was addressed by utilizing a movable pedal assembly to ensure drivability by drivers with crotch height of anywhere from 30” to 36”. This range was chosen to accommodate male drivers who fall between the 5th and 95th percentile according to the Design Criteria for Military Systems, Equipment and Facilities. This range also accommodates female drivers within the 50th-99th percentile. Competition • Static Events – Cost and Manufacturing Analysis – Presentation – Design Competition • Dynamic Events – Acceleration – Skid Pad – Autocross – Fuel Economy – Endurance Customer Requirements • Minimum 60 inch wheel base • Must have 4 wheels that are not in a straight line. • Wheels must be a least 8 inches in diameter. • Must have dry (slick) and wet (treaded) tires to compete. AET Customer Requirements • Steering must affect at least two wheels. • Brakes must act on all four wheels from a single control. • Must be equipped with 5 point safety harness. • Engine is restricted to 610cc or less. • Air intake restricted to 20 mm. AET Frame PRV Analysis • Static loading using Pro-Mechanica • Loads- – 650 lbs • Car and Driver – 2 G’s Lateral – 2 G’s Braking – 3 G’s Vertical PRV Analysis AET PRV PRV SAA Ex. Working Drawing SAA Routing Sheet COMPANY NAME: PSU Racing Part Name: Rear Passenger Hub Date: 11/17/2006 Size of Run: 1 Unit Oper. # Description OperationMaterial Time Feed/ Speeds 5 Rapid Prototype RPT Poly 24hr NA Create RPT part 10 Create Flask Ram Green Sand .5hr NA flask Ram part in green sand Add gating system Remove patterns Place on pouring line 15 Pour Part Casting 356 Al Alloy 2hr NA Pour 356 Al Alloy in flask Allow to cool Break out part 20 Solution Treatment Heat treat 356 Al Alloy 24hr NA Heat treat part in furnace Quench Age part in furnace 25 Machine Holes Mill 356 Al Alloy 1hr ? Machine bearing surface Machine ball joint clearance MD/AT Final Assembly SAA SAA MD Conclusions • In conclusion, our vehicle design is simple yet effective. Through F.E.A, destructive testing, and research it is determined this design meets or exceeds all criteria set forth by the S.A.E. and PSU Racing. The goals of manufacturing a product that is easy to manufacture, reliable, and cost effective were met. By meeting the goals set forth, a vehicle that is marketable to the average weekend racer was produced. We appreciate the time taken by the advisory committee to review this report. Questions?
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