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…