918 Spyder – Lightweight design and innovative materials
Schlatt, Switzerland, 9 th October 2014
The 918 Spyder project Porsche supersportscars have a long tradition
1986 – 959 1996 – 911 GT1 2003 – Carrera GT 2013 – 918 Spyder
Street
1980 1990 2000 2010 2015
1970 – 917 1998 – GT1 2005 – RS Spyder 2014 – 919 Hybrid
Race 918 Spyder – fusion of contradictions Design Easy drivability
M2 M1 M1 M2
E-drive High performance
Nordschleife Boost: 286 hp 0 - 100 km/h: 2.6 s E-Range: 31 km 0 - 200 km/h: 7.2 s
CO 2 Emission: 70 g/km Nordschleife: 6:57 min System extra weight owed to different components
Electric system Pressure tank
• Two permanent magnetized synchronous • lockable pressure tank to prevent fuel vapor motors from escaping to environment • Performance oriented high voltage battery with lithium ion cells (water-cooled by an inside cooling plate) • Two power electronics modules • High voltage wiring System extra weight owed to different components Cooling system cooling circuit water: • High temperature (combustion engine): • 2 front radiators, 1 rear radiator • Expansion tank aluminum, external ventilation valve (opening pressure: 1.6 bar) • Fluid capacity: 23.9 l • Middle temperature / Low temperature (electric machine, power electronics, battery): • 1 rear radiator • Expansion tank aluminum • Electric feed pump • Fluid capacity: 9.4 l cooling circuit oil: • 1 oil-to-air radiator High temperature - cooling circuit Middle / Low temperature - cooling circuit • Fluid capacity: 10.7 l Oil - cooling circuit Compensation of hybrid system extra weight
Interior quality and [Kg] vehicle safety - 209 +43 +48 - 40
Gear box (7 gear PDK) Sound system
+317 1,883 1,634 Battery system Electric drive train High voltage wiring Cooling 1,475
Curb weight in accordance with DIN How to manage lightweight design?
Lightweight-design in sports car development Lightweight management
Material lightweight Conceptional lightweight Intergration of functions design design Material lightweight design Choice of technology depends on the production volume
Number of pieces
10 parts/year 600 parts/year 5,000 parts/year
• RTM • Out of Autoclave • Prepreg-Autoclave ° Prepreg press • Pultrusion ‰ CFRP moulds ‰ Steel (aluminum) moulds
Investment / unit costs / peak production volume / quality Capacity of the market Rolling Chassis All-carbon fiber structure: a unique feature of Porsche supersports cars
Monocoque Back Carrier • Crash integrity • Integration of rear • Vehicle stiffness wing drive, rear • Visible carbon fiber lights, control unit • Integration of fuel tank and HV-battery
Engine Frame • Required to resist temperatures of 150 °C • Integration of rear axle and rear Support Frame Front Axis drive train • Integration of front axle and front electric motor Resin Transfer Moulding Prepreg - Autoclave Resin Transfer Moulding: process chain
Preforming & Assembly Resin injection Integral part
• Use of economical fabrics and • Integral hollow structure preforming methods • 6-piece steel mould, 44 tons • Large visible carbon fibre areas • Optimized single preforms (2,500 mm x 2,000 mm x 1,200 mm) • Moderate industrialisation possible • Integral RTM-process by Mubea Carbo • Low injection pressure • Motorsport performance Tech • Epoxy resin system First use of carbon inserts in a street legal production car
27 cast aluminum inserts
10 C-SMC inserts Different ways of corrosion protection Duplex-coating Adhesive film FGRP • Duplex coated steel bolt for • Inserts are covered in adhesive • Milled sacrificial layer made out structural connections film before used in the tool of glass fibre, in contact area • Surface S628 (zinc-nickel alloy with metalic components. with restricted layer thickness) • organic coating (KTL) Static of the carbon fiber structure
Carrera GT 918 Spyder
• Static tortional stiffness: • Static tortional stiffness: 28,500 Nm/ ° > 40,000 Nm/ °
• Static bending stiffness: • Static bending stiffness: 9,000 N/mm > 16,000 N/mm Comparison of 918 Spyder and Carrera GT carbon fiber structure Formula Carrera GT 918 Spyder • Lightweight rating: • Weight: = 190 kg • Weight: = 215 kg • Static rotational stiffness: • Static rotational stiffness: L = = 28,500 Nm/° > 40,000 Nm/° ∗ • Lightweight rating: • Lightweight rating: (Lower values are better)
1.5 1.2
‰ average passenger cars > 2.5 CFRP – overview car body panels
Bonnet Roof Roof Roll bar cover Outside mirror
Wing Wing Side panel front
Door outside Door inside Fender
Door Sill
Resin Transfer Moulding Prepreg - Autoclave Prepreg - Out of Autoclave Front cover – low weight thanks to CFRP
Carrera GT 918 Spyder
• CFRP front cover with V-gap • Affecting CFRP front cover • Prepreg with honeycomb • Prepreg monolithic with bonded reinforcement • Bolt-on points realized through aluminum inserts • Bolt-on points realized through steel inserts surface approx. 1.1 m² • surface approx. 2.3 m² • Total weight 5.5 kg • Total weight 11 kg
+ 5.5 kg Comparison of different Porsche front covers
weight [kg] weight per unit area [kg/m²] 20 8
18 7 16 6 14 5 12
10 4
8 3 6 2 4 1 2
0 0 Macan Panamera Carrera GT 918 Spyder Macan Panamera Carrera GT 918 Spyder Innovative door system
Carrera GT 918 Spyder
• Door glass 3.32 kg • Door glass 3 kg • Steel side intrusion bar 3.1 kg • Steel side intrusion bar 4.75 kg • Door panel out of CFRP RTM (inside) 3.65 kg • Door panel out of CFRP Prepreg 5.76 kg and Prepreg (outside)
- 4.0 kg CFK stabilizer
Steel construction CFRP construction
• Weight optimised tubular steel stabiliser with thin • Braided CFPR-torsion tube with bonded aluminum wall technology lever • Coupling rod welded out of steel components • Coupling rod aluminium with rolled Unibal-bearing • Stabilizer clamps out of aluminum • Stabilizer clamps out of aluminum • Total weight 2.6 kg • Total weight 1.1 kg • Total costs 100 % • Total costs 3,461 %
- 1.5 kg CFRP oil tank
911 GT3 918 Spyder
• Oil defoaming through cyclone separator • Oil defoaming through innovative oil guidance • Steel-wall thickness 0.6 – 0.8 mm • CFRP-wall thickness 1.6 mm • Fuel tank weight 3.8 kg • Fuel tank weight 1.95 kg • Minimal oil capacity 4.2 l • Minimal oil capacity 5.5 l • Purchase price 100 % • Purchase price 590 %
- 1.85 kg 918 Spyder Weissach package: Titanium vs. steel
• 12 titanium screws (front axle) + 10 titanium screws (rear axle) • Titanium has 57 % lower density than steel • Saved weight 0.7 kg Comparison of different exhaust systems
911 Carrera S 991 GT3 981 Boxster S Carrera GT 918 Spyder
42.6 kg 39.6 kg 34.4 kg30.5 kg 28.1 kg
Stainless steal Stainless steal Stainless steal Stainless steal Top pipes and thin- exhaust system exhaust system exhaust system exhaust system walled Inconel® Exhaust System: Stainless Steel vs. Inconel ®
Exhaust system 911 GT3 Exhaust system 918 Spyder
• Stainless steel exhaust system • Top pipes and thin-walled Inconel® • Total weight 39.6 kg • Total weight 28.1 kg
- 11.5 kg Integration of functions Integration of Air intake box into the engine frame
Air intake box CFRP engine frame
Air filter Rear e-motor cooling air
Air to combustion engine Carbon fiber clean air box Vaccum container integrated in heat-protection shields
Heat-protection panel Vacuum container
• Heat-protection panel for engine electrics • Additional use as heat protection element • High temperature CFRP • High temperature CFRP • Specific air rooting • Total weight 6.8 kg Shear panel integrated in HV battery Floor panel
Battery Housing
• Mechanical integration of the high voltage battery • Contributes 3% to global torsion stability ‰ disproportionate • Floor panel builds the aerodynamic undershield of the car • Total weight 5 kg Conceptuel lightweight design Wheel hub design
Porsche standard 918 Spyder
• Weight front axle 22.3 kg Wheel carrier/hub/bearing/drive train • Weight rear axle 22.9 kg • Saved weight front axle 2 x 1.7 kg • Saved weight rear axle 2 x 2.3 kg
- 8.0 kg Combustion Engine
Carrera GT 918 Spyder
• V10 5.7l 40 V DOHC naturally aspirated • V8 4.6l 32 V DOHC naturally aspirated • P max 612 hp (447 kW) @ 8,000 rpm • P max 608 hp (447 kW) @ 8,700 rpm • P specific 107.4 hp/l (78 kW) @ 8,000 rpm • P specific 132 hp/l (97 kW/l) @ 8,700 rpm • M max 590 Nm @ 5,750 rpm • M max 540 Nm @ 6,700 rpm • Total weight 205 kg • Total weight 137 kg
- 68.0 kg Lightweight technology for the engine
V8 crankshaft Cayenne (naturally aspirated engine) 918 Spyder
• Steel crankshaft • Steel crankshaft, Axial oil supply • Total weight 20.7 kg • Total weight 12.7 kg
- 8.0 kg Not always CFRP
CFPR construction PA6GF30 construction Total weight 2.24 kg Total weight 3.48 kg Part costs 1,680 € Part costs 110 € Investment 158,000 € Investment 170,000 € TTO 1.75 Mio € TTO 0.27 Mio €
1.48 Mio. € 1,300 €
-1.24 kg kg x vehicle
Limit of costs per kg = 1,000 € ‰ choice of PA6GF30 construction The result of uncompromising lightweight construction Fastest road vehicel: 6:57 minutes on the Nordschleife
08:16 Electric vehicle 08:02 Electric vehicle Petrol engine 07:48 Petrol engine Petrol engine 07:33 Carrera GT Target 918 Spyder Petrol engine 07:19 Petrol engine Time Time in minutes 997 GT2 RS 07:04 Hybrid Hybrid 918 Spyder 06:50 0 50 100 150 200 250 300 350 400 450 500 CO2 Emissions in g/km 3.1 – 3.0 l/100 km fuel consumption (NEDC) Overwhelming press feedback „Denn Vollgas entfesselt nichts anderes als eine Urgewalt , die über “The 918 an astounding technical beide Achsen herfällt“ achievement . An absolutely all-new car, using bleedin'-edge techniques wherever you look”
The Porsche 918 Spyder is a Work of Scientific Madness: Welcome to the 21st century supercar. „Bestechend präzise , irrwitzig press schnell und beinahe spielerisch zu beherrschen “ echo “It‘s like a sprinter falling out of bed and going straight into a world record ”
„Alles in allem bietet der 918 Spyder “Schon rein elektrisch ein Renner , wird der einen überwältigenden Eindruck von Porsche mit der vereinten Kraft der drei Motoren Geschwindigkeit bei gleichzeitig zu einer Rakete . Allerdings braucht man nicht den völlig unkritischem Benehmen “ Mut eines Evel Knievel, um diese Rakete zu reiten.” Summary
• Plug-In Technology is suited to beat conventional vehicle technology • Lightweight design is the key factor for success of Plug-In Hybrid • For successful lightweight design lightweight materials, lightweight concept and functional integration has to be used • Supersportscars can be “ice breakers” for new technologies e.g. CFRP, electric 4 WD Thank you