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TRANSCRIPT
Design Presentation
Chalmers Formula Student
2012-01-18
TC Frame Engine Suspension (fika) UM Electronics Body
Technical Communication Jens Kjellerup
Andreas Flodström
Anita Schjøll Brede
Confirmed
Hockenheim, Germany July 31st – Aug 5th
• Registration: Rules Quiz, first come first serve.
• 01:19
• First team to finish!
Competitions
Awaiting
Silverstone, UK July 11th – 15th
• Business Logic Case
Baltic Open Early September
Darmstadt, Germany
• 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”
Business Logic Case
• Adjustability
• Measurability
• Easy Repairs
Conditions are not always the same – we see no reason why your car should be.
Exclusive Preview
(for attendees only)
Website
Competitions
• Practical Organization
• Preparing for Static Events – Design Report
– Cost Report
– Business Presentation
Moving Forward
Formula Student
• Marketing Strategy
• Events
• Partnerships
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.
Questions?
Frame Stefan Venbrant
Sharan Prathaban
Erik Hartelius
Eva Andersson
“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”
Subgroup goal
Design Targets
o Weight (Kg) Lowest possible
o Torsional Stiffness (Nm/deg) 3500
o Stiffness/Weight Ratio Highest possible
Design Methodology
o Suspension
o Engine
o Packaging
o Analysis
o Iterations
The Design
• Triangulated polygonal cross sectioned frame
• Main Hoop bent forwards
• Engine and driver close to the ground
• Driver far back
• No “box”
• Nodes for suspension hard points
• High Main Hoop bracing
Nodes finalized using FEA
Analysis Technique • Testing for torsional stiffness
• Fix rear rocker mounting points
• Load at front rocker points
• Measure deflection at the loading points
Stiffness=
• Vertical/Lateral Bending • Deflection of hard points at max force
• Ensure whole frame moves as one unit
• Well distributed force
• Axial forces - Compression and Tension
• Visualization of load paths
• Optimization of thicknesses
• Removal of unnecessary tubes
Optimization
3150
3200
3250
3300
3350
3400
3450
3500
3550
0% 10% 20% 30% 40% 50% 60% 70%
To
rsio
na
l S
tiff
ne
ss (
Nm
/d
eg
)
% Movement of Point
Problems faced during design and analysis
• Attain required stiffness
• Engine removal
• Lowest weight
• Fuel tank placement
• Steering system
• Rear hard points nodes
CFRP
• Complex to distribute loads
• Manufacturability
• Incorporated too late in design phase
Results
Parameters Initial Goal Revised Goal Final Design
Weight (Kg) 27 Light as possible 30.8
Torsional Stiffness
(Nm/deg)
2500 3500 3512.6
Stiffness/Weight Ratio 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
Design Methodology
• Research
• Calculations
• Simulations
• Testing
Aluminum Honeycomb
• Easy made calculations
• Reliable
• Light
Sheet metal
• Aluminum or Mild steel
• Made in house
• Cheap
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.
Questions?
Engine Sebastian Krause
Blago Minovski
Tony Persson
Andreas Widroth
” To deliver a reliable and weight optimized engine system with sufficient power and possibility for low fuel consumption to FSUK 2012 ”
Subgroup goal
Intake system
• 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
• 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
• 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
Fuel pressure regulator:
• Bosch
• Regulating pressure 3,8 bar
• Compact and lightweight
Fuel system
• Reliability
• Manufacturability
• Aluminum for the cover
• Steel for the trigger wheel
• Manufactured inhouse
• Stock fuel rail
• Coil on plug solution (Volkswagen)
Ignition system
Cooling System
Parameters • Radiator size:
– 320 H x 370 W x 32 T
– Aluminum McCord matrix
• Fan size: – 11inch
• One pass – reliability
– Aids natural water circulation (siphoning)
Radiator
Engine
Water pump
Exchanger
Oil pump
Total weight: 5,9kg
• Measurement of CFS11 cooling temperatures
Cooling System Requirements
Time [s] Fuel [kg] Total Fuel
energy [kJ]
Rate of heat rejection
[kW]
Total rejected heat [kJ]
Percentage of total fuel
energy Comment
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
Cooling System Requirements
FSUK11 Endurance Event
Fuel used [kg]
LHV [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
Heat dissipation
[kW] Water flow
[l/min] Air speed
[m/s] Fan contribution
[Pa] Ambient t°
[C°] Engine t°
[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
• Dual pickup
• Modified pressure release valve
Lubrication
Transmission and Final drive
Weight reduction of the transmission
• Unused gears replaced by aluminum inserts
Final drive
• 13/44 teeth
85 kg
Total weight
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.
Questions?
Suspension Ibrahim Bakirci
Christoffer Routledge
Dean Todevski
“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.”
Subgroup goal
• 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
Methodology • Calculations, matlab,
• Recommendations, previous experience
• Dampertest
Problems • Dampers to stiff
• Compromise: to stiff dampers - adjustability
Anti-roll bar
Design targets • Adjustability
• Low weight
• Simplicity
Methodology • Calculations, matlab
• Previous experience
Problems • 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
Methodology • Improvement of last year
• Reduce weight on purchased part
Problems • Packaging with pedalbox
• Integration with dashboard
Balljoints and quick adjustment
Design targets • Adjustability
• Design for manufacturing
• Reliability
Methodology • Benchmarking
• Fatigue/ANSYS
Problems • Loadcases
• Packaging
Front axle Rear axle
Target Result Target Result
Wheelbase - - - - 1600 mm
Track width 1210 mm 1210 mm 1160 mm 1160 mm
Weight distribution 46% - 54% - -
Center of gravity height
- - - - 280 mm above ground
Castor 5 deg 5 deg - -17.9 deg -
Mechanical trail 20 mm 10.89 mm Negative -41.4 mm -
Scrub 30-35 mm 45.3 mm As small as possible 38.6 mm -
Roll center height static
35 mm above ground 36 mm above ground 49 mm above ground
61.6 mm above ground -
Anti dive/squat 0 / - % 0 / 0 % 0 / 15 – 20 % 0 / 18 % -
Ackermann 50 – 100 % 65 % - - -
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
Results – Suspension geometry
Results
Dampers and springs • 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 • Weight saving
• Adjustability: Pre defined steps
• Simplicity
• Rollgradient 1deg/g
Results
Steering systems • Weight reduction with 550g
• Adjustable steering arm
• No change in steering effort
Inserts and quick adjustments • Shims design – fast adjustment
• Finetuning through rodends
• CNC-operations minimized
• Water cutting – Rockers
– Steering column mount
– ARB levers
• CNC-manufacturing – Inserts
– Quick adjustments
• Welding – Steering system
• Laser cutting – Brackets
• Glued – Wishbones to inserts
Manufacturing methods
• Al 7075 in stressed components
• High strength steel
• Pull winded carbon fiber tubes
• Loctite 9466 with glass balls
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.
Questions?
Unsprung Mass Erik Bergman
Marc Ollé Bernades
Jean-Adrien Develet
Oskar Eklund
Simon Johansson
“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”
Subgroup goal
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 Rear disc assembly
Assembly weight: 789g
• High stiffness over weight ratio
• Grooves and wave shape to clean pads
Assembly weight: 680g
Pedal box Characteristics
• 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 Rear
Target Achieved
Camber Compliance (deg/Nm)
0,0003 0,0003
Weight, front (kg)
1 0.8
Weight, rear (kg)
1 0.9
Rear and Front Hub Simulation analysis
Driveline
Constant velocity inner housing
Diff mounts & Sprocket
Left Diff mount - disassembled
Right Diff mount
Sprocket assembly
Targets
Target Achieved
Camber compliance, wheel assembly (deg/Nm)
0.0003 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
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.
Questions?
Electronics Andreas Andersson
Frej Edberg
Jonas Nöland
Victor Påsse
“Deliver a reliable system, powerful and advanced enough to meet the demands from the other subgroups”
Designed to…
• Operate the car
• Make testing more effective – More data, live presentation at the track, flexibility
Subgroup goal
Design targets
• 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 – State requirements
• Basic features
• Testing
• Evaluation
• Refining and expanding
Test circuit v1
Eagle CAD front and rear node circuits
Design methodology
Mechanical parts
• Analyze different solutions
• Evaluate – Over-all performance
– Function
– Accessibility
– Manufacturing
– Consequences
• CAD models
• FEM-calculations
Test circuit v1
Eagle CAD front and rear node circuits
• 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
Results
(…) = CFS11
PC interface
Results
• CAD assembly • Packaging issues
CAD Assembly
Results
• Clutch cylinder
– Auto clutch
– Launch Control
– Down shift
Clutch cylinder bracket
• Brackets
– Watercut
• Circuits
– Produced by MakePCB, China
– Completed in house
Manufacturing
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.
Questions?
Body Lucas Börjesson
Sven Rehnberg
Robert Svensson
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 sound ergonomic environment for the driver, sufficient cooling for the engine and low overall drag in order to reach 800 points at FSUK 2012.
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 high downforce in order to reach 800 points at FSUK 2012.
Subgroup goal
Ergonomic targets
• Rules compliant
• Subjective – comfortable
Design targets
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
Ergonomic methodology
• Reading literature
• Benchmarking
• Simulation using Catia and Jack
Design methodology
Aerodynamic methodology
• Reading literature
• Benchmarking
• Simulation using Carmaker and CFD
Ergonomics
Results vs. design
Aerodynamics
Results vs. design
To be continued…