Design Presentation Presentation Chalmers Formula Student TC Frame Engine Suspension (fika) UM Electronics Body
2012-01-18
Technical echnical Communication Communication Jens Kjellerup Andreas Flodström Anita Schjøll Brede
Technical echnical Communication Communication Jens Kjellerup Andreas Flodström Anita Schjøll Brede
Competitions
Confirmed
Awaiting
Hockenheim, Germany
Silverstone, UK
July 31st – Aug 5th
July 11th – 15th
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Registration: Registration: Rules Quiz, first come first serve. 01:19 First team to finish!
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Business Logic Case
Baltic Open Early September
Darmstadt, Germany
Business Logic Case
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Mandatory for Silverstone Registration Ties together Static events Business Presentation Design Report Cost Report “… encouraging teams to consider the competing aspects of design, cost and marketing early in the project” –
Conditions are not always the same we see no reason why your car should be. –
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Adjustability Measurability Easy Repairs
Website
Exclusive Preview (for attendees only)
Moving Forward
Competitions •
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Practical Organization Preparing for Static Events –
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Design Report Cost Report Business Presentation
Formula Student •
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Marketing Strategy Events Partnerships
Questions?
To gain professional experience we will, through efficient engineering and teamwork while learning from previous experience, deliver a well-tuned and reliable solution in order to achieve 800 points at FSUK 2012.
Frame Stefan Venbrant Sharan Prathaban Erik Hartelius Eva Andersson
Subgroup goal
“Through cross-functional engineering, the frame subgroup will deliver a
well packaged, light and strong frame with high torsional stiffness in order to reach the goals set by the team”
Design Targets o
Weight (Kg)
Lowest possible
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Torsional Stiffness (Nm/deg)
3500
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Stiffness/Weight Ratio
Highest possible
Design Methodology o o o
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Suspension Engine Packaging Analysis Iterations
The Design
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Triangulated polygonal cross sectioned frame Main Hoop bent forwards Engine and driver close to the ground Driver far back
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No “box”
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Nodes for suspension hard points High Main Hoop bracing
Nodes finalized using FEA
Analysis Technique •
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Testing for torsional stiffness Fix rear rocker mounting points Load at front rocker points Measure deflection at the loading points
Stiffness=
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Vertical/Lateral Bending Deflection of hard points at max force
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Ensure whole frame moves as one unit Well distributed force Axial forces - Compression and Tension
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Visualization of load paths Optimization of thicknesses Removal of unnecessary tubes
Optimization 3550 ) g3500 e d / 3450 m N ( s 3400 s e n3350 f f i t S3300 l a n o3250 i s r o T3200
3150 0%
10%
20%
30%
40%
% Movement of Point
50%
60%
70%
Problems faced during design and analysis •
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Attain required stiffness Engine removal Lowest weight Fuel tank placement Steering system Rear hard points nodes
CFRP •
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Complex to distribute loads Manufacturability Incorporated too late in design phase
Results Parameters
Initial Goal
Revised Goal
Weight (Kg) Torsional Stiffness (Nm/deg) Stiffness/Weight Ratio
27 2500
Light as possible 3500
Final Design 30.8 3512.6
92.6
Highest possible
114.2
Manufacturing methods and material choices • • • •
Laser cutting Bending Welding Sections
Frame Tube Material SAE 4130 –
Impact Attenuator
Two IAs are being investigated: Aluminum honeycomb Sheet metal IA •
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Design Methodology •
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Research Calculations Simulations Testing
Aluminum Honeycomb •
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Easy made calculations Reliable Light
Sheet metal •
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Aluminum or Mild steel Made in house Cheap
Questions?
To gain professional experience we will, through efficient engineering and teamwork while learning from previous experience, deliver a well-tuned and reliable solution in order to achieve 800 points at FSUK 2012.
Engine Sebastian Krause Blago Minovski Tony Persson Andreas Widroth
Subgroup goal
” To deliver a reliable and weight optimized engine system with sufficient power and possibility for low fuel consumption to FSUK 2012 ”
Intake system
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Lightweight: ~1.6 kg Runner total length - 320mm Plenum volume – 4L Throttlebody - modified butterfly valve Plenum and restrictor – Carbonfiber Runners and throttlebody - Aluminium
Exhaust system
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Lightweight: ~4.6 kg Low center of gravity ~150 mm lower than CFS11 Minimize turbulence ~no rapid changes in diameter Manufacturability ~only one weld on headers Stainless steel pipes, 1mm External bending by company Aluminum muffler cover New collector design
Fuel system
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Lightweight Low center of gravity Manufacturability Aluminum for fuel tank Manufactured inhouse Dry weight ~ 2,8 kg Total weigth ~7 kg
Fuel system
Fuel pump: MSD ignition 2225 Compact and lightweight Operating pressure ~ 4 bar •
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Fuel pressure regulator: Bosch Regulating pressure 3,8 bar Compact and lightweight •
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Ignition system
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Reliability Manufacturability Aluminum for the cover Steel for the trigger wheel Manufactured inhouse Stock fuel rail Coil on plug solution (Volkswagen)
Cooling System Radiator
Parameters •
Radiator size: –
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Water pump
Engine
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Oil pump
Total weight: 5,9kg
Fan size: –
Exchanger •
320 H x 370 W x 32 T Aluminum McCord matrix 11inch
One pass –
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reliability Aids natural water circulation (siphoning)
Cooling System Requirements •
Measurement of CFS11 cooling temperatures
Total Fuel Rate of heat Total Percentage Time [s] Fuel [kg] energy rejection rejected of total fuel Comment [kJ] [kW] heat [kJ] energy Run2 160 0.21375 9405 8.84 1415 15.05% Cold engine Run3 658 0.9975 43890 11.11 7310 16.66% Warm engine Run4 480 0.64125 28215 11.16 5355 18.98% Warm engine Run5 555.3 0.78375 34485 7.46 4140 12.01% Cold engine
FSUK11 Endurance Event Fuel used LHV [kg] [kJ/kg]
Time [s]
Total energy [kJ]
Total Power [kW]
Mean Cooling capacity [kW]
Mean Speed [m/s]
Mean speed [km/h]
University of Stuttgart
2.7
44000
1339
117117
87.4
17.5
16.4
59.13
University of Hertfordshire
2.9
44000
1452
128436
88.5
17.7
15.2
54.56
Chalmers University of Technology
2.9
44000
1562
126192
80.8
16.2
14.1
50.69
Queen's University Belfast
2.8
44000
1596
122199
76.6
15.3
13.8
49.64
Cooling System Requirements Heat dissipation Water flow Air speed Fan contribution Ambient t° Engine t° [kW] [l/min] [m/s] [Pa] [C°] [C°] High load 20 45 8.59 60 35 105 Medium load 17 25 4.06 60 35 105 Low load 11 12 1.06 60 35 105
Lubrication •
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Dual pickup Modified pressure release valve
Transmission and Final drive
Weight reduction of the transmission •
Unused gears replaced by aluminum inserts
Final drive •
13/44 teeth
Total weight
85 kg
Questions?
To gain professional experience we will, through efficient engineering and teamwork while learning from previous experience, deliver a well-tuned and reliable solution in order to achieve 800 points at FSUK 2012.
Suspension Ibrahim Bakirci Christoffer Routledge Dean Todevski
Subgroup goal
“Through simple design and high manufacturability, we will secure the stiffness and reliability of the suspension and steering which will allow predictability , adjustability and a high degree of tuning possibilities. The low weight , center of gravity and a well-tuned car will make us reach 800 points in FSUK 2012.” •
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Simplicity Reliability Predictability Adjustability Manufacturability Low weight
Suspension geometry Design targets Low bump/roll steer Stable roll center Reduced steering effort Stiff frame nodes • • • •
Methodology Lotus SHARK •
Problems No-box solution Compromises Packaging issues • • •
Dampers and springs Design targets Adjustability Damper response Less body roll and pitch than CFS11 •
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Methodology Calculations, matlab, Recommendations, previous experience Dampertest •
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Problems Dampers to stiff Compromise: to stiff dampers - adjustability •
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Anti-roll bar Design targets •
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Adjustability Low weight Simplicity
Methodology •
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Calculations, matlab Previous experience
Problems •
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Very high stresses in torsion bar Packaging issues
Steering system Design targets Reduce the weight of purchased part with 500 g Reliability Adjustability (20 sec per side) Reduce play and steering effort •
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Methodology Improvement of last year Reduce weight on purchased part •
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Problems Packaging with pedalbox Integration with dashboard •
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Balljoints and quick adjustment
Design targets •
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Adjustability Design for manufacturing Reliability
Methodology •
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Benchmarking Fatigue/ANSYS
Problems •
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Loadcases Packaging
Results – Suspension geometry Front axle
Rear axle
Target
Result
Target
Result
Wheelbase
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Track width
1210 mm
1210 mm
1160 mm
1160 mm
Weight distribution
46%
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54%
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Center of gravity height
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280 mm above ground
Castor
5 deg
5 deg
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-17.9 deg
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Mechanical trail
20 mm
10.89 mm
Negative
-41.4 mm
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Scrub
30-35 mm
45.3 mm
As small as possible
38.6 mm
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Roll center height static
35 mm above ground
36 mm above ground
49 mm above ground
61.6 mm above ground
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Anti dive/squat
0/-%
0/0%
0 / 15 – 20 %
0 / 18 %
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Ackermann
50 – 100 %
65 %
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Camber gain
0 deg/max eff. roll
0.5 deg camber/deg roll
0 deg/max eff. roll
0.4 deg camber/deg roll
Rollcentre migration vert/lat
1mm/deg roll
0.03mm/deg roll 2mm/deg roll
1mm/deg roll
0.06mm/deg roll 0.18mm/deg roll
1600 mm
Results
Dampers and springs •
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3.2 Hz Front, 3.4 Rear Motionratio 1.25 (Wheel/Damper) Compromise between softer settings and damper response Stiffer in roll/pitch and bump
Anti-roll bar •
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Weight saving Adjustability: Pre defined steps Simplicity Rollgradient 1deg/g
Results Steering systems •
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Weight reduction with 550g Adjustable steering arm No change in steering effort
Inserts and quick adjustments •
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Shims design – fast adjustment Finetuning through rodends CNC-operations minimized
Manufacturing methods
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Water cutting –
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CNC-manufacturing –
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Steering system
Laser cutting –
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Inserts Quick adjustments
Welding –
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Rockers Steering column mount ARB levers
Brackets
Glued –
Wishbones to inserts
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Al 7075 in stressed components High strength steel Pull winded carbon fiber tubes Loctite 9466 with glass balls
Questions?
To gain professional experience we will, through efficient engineering and teamwork while learning from previous experience, deliver a well-tuned and reliable solution in order to achieve 800 points at FSUK 2012.
Unsprung Mass Erik Bergman Marc Ollé Bernades Jean-Adrien Develet Oskar Eklund Simon Johansson
Subgroup goal
“By being the best engineers in the team, we will deliver a reliable and
adjustable subsystem with sufficient stiffness/weight ratio and good performance and thereby contribute to the team goal of reaching 800 points at FSUK 2012”
Brake System Main specifications Calipers Front: ISR 22-048, 4 piston 25 mm bore, 460 g Rear: ISR 22-049, 2 piston 25 mm bore, 290 g Discs Front: OD: 240 mm, ID: 186 mm, 687 g Rear: OD: 220 mm, ID: 166 mm, 595 g Master cylinders Front: 14 mm piston bore, 210 g Rear: 14 mm piston bore, 210 g
Brake deceleration in combination with pedal effort (applied foot force per g deceleration) targets meet and exceeded
Brake System Front disc assembly
Assembly weight: 789g •
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High stiffness over weight ratio Grooves and wave shape to clean pads
Rear disc assembly
Assembly weight: 680g
Pedal box
Characteristics •
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Overall mass: 2.5 kg Pedal ratio: from 4.5 to 5 AP Racing MC + balance bar Brake pedal: alu 7075, CNC Throttle pedal: alu base + carbon fibre beam and foot support Two separate heel supports in carbon fibre Length tuning: 7 positions, 192mm. Spring mounted pins.
Rims
Target
Achieved
Camber Compliance (deg/Nm)
0,0003
0,0004
Weight (kg)
1,6
4,5
Uprights
Front
Target
Achieved
Camber Compliance (deg/Nm)
0,0003
0,0003
Weight, front (kg)
1
0.8
Weight, rear (kg)
1
0.9
Rear
Rear and Front Hub
Simulation analysis
Driveline Constant velocity inner housing
Diff mounts & Sprocket
Left Diff mount - disassembled
Sprocket assembly
Right Diff mount
Targets
Target
Achieved
Camber compliance, wheel 0.0003 assembly (deg/Nm)
Yet to be verified
Weight UM (kg)
36
39.6
Brake acceleration (g)
1.7
1.9
Pedal effort (N/g)
350
335
Pedal box weight (kg)
2.5
2.5
Questions?
To gain professional experience we will, through efficient engineering and teamwork while learning from previous experience, deliver a well-tuned and reliable solution in order to achieve 800 points at FSUK 2012.
Electronics Andreas Andersson Frej Edberg Jonas Nöland Victor Påsse
Subgroup goal
“Deliver a reliable system, powerful and advanced enough to meet the demands from the other subgroups”
Designed to… •
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Operate the car Make testing more effectiv e ffectivee –
More data, live presentation at the track, flexibility
Design targets
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Weight <11 kg Accessibility Reliability Meet requirements from the team Sensors, sampling rate etc. –
Design methodology
Electrical and software parts – a top-down approach Investigation
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State requirements
Test circuit v1
Basic features Testing Evaluation Refining and expanding Eagle CAD front and rear node circuits
Design methodology
Mechanical parts Analyze different solutions Evaluate •
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Test circuit v1
Over-all performance Function Accessibility Manufacturing Consequences
CAD models FEM-calculations Eagle CAD front and rear node circuits
(…) = CFS11 Results •
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Weight < 9 kg (12 kg) - Estimations Logging 40 parameters (8-10) Accessibility Quick releases, better placement New features Serial com Wireless com. with PC-interface Pneumatic clutch –
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PC interface
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CAD assembly Packaging issues
CAD Assembly
Results •
Clutch cylinder Auto clutch Launch Control Down shift –
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Clutch cylinder bracket
Manufacturing •
Brackets Watercut Circuits Produced by MakePCB, China Completed in house –
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Questions?
To gain professional experience we will, through efficient engineering and teamwork while learning from previous experience, deliver a well-tuned and reliable solution in order to achieve 800 points at FSUK 2012.
Body Lucas Börjesson Sven Rehnberg Robert Svensson
Subgroup goal Previous subgroup goal By implementing efficient engineering and learning from previous experience the body subgroup will deliver a lightweight and reliable solution which garanties a
New subgroup goal By implementing efficient engineering and learning from previous experience the body subgroup will deliver a lightweight and reliable solution which garanties a
sound ergonomic environment for the driver, sufficient cooling for the engine and low overall drag in
sound ergonomic environment for the driver, sufficient cooling for the engine and high downforce in
order to reach 800 points at FSUK 2012.
order to reach 800 points at FSUK 2012.
Design targets
Ergonomic targets Rules compliant Subjective – comfortable •
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Aerodynamic targets Lift = -500N at 56 km/h Cd <1 Frontal area <1.33 m² Drag <200N at 56 km/h Mass flow through radiator = 0.56 kg/s at 56 km/h •
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Design methodology
Ergonomic methodology Reading literature Benchmarking Simulation using Catia and Jack •
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Aerodynamic methodology Reading literature Benchmarking Simulation using Carmaker and CFD •
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Results vs. design
Ergonomics
