COST EFFICIENT COMPOSITE PLATFORM WITH INTEGRATED ENERGY STORAGE FOR A HYDRAULIC HYBRID Target Energy Consumption Hydraulic Hybrid Composite Platform Drivetrain Accumulator Platform & Body Weight Cost Comparison
CAFE - Fuel Economy Target 2025 4.3 Liter/100km (54.5 MPG) 114 gr/100km CO2 Currently 6.5 Liter/100km (36 MPG) 173 gr/100km CO2 Source: NHTSA Summary of Fuel Economy Performance, NHTSA MY2017-2025 Factsheet
Factors influencing fuel consumption Losses & Gains Weight Air drag Drivetrain efficiency Tire rolling resistance Cross section x Drag coefficient Combustion efficiency Frictional losses Energy recuperation
Energy consumption of various vehicle concepts Fig. 1: Energy efficiency for cars of the same type (cross section, air drag, tires) depending on weight, drivetrain efficiency and recuperated braking energy.
Comparison of drive systems - Electric / Hydraulic Table I: Comparison Electric / Hydraulic Drives Electric Hydraulic Motor [1] Weight 1.2 kw/kg 25 kw/kg Low weight of car, unsprung mass of wheel. Efficiency = = Wheel motors replace brakes. Recuperation 20% 80% Full recuperation of braking energy. Cost 1 0.3 No dependency on foreign sources of material. Energy Storage [1] Specific Energy 150 kj/kg 10 kj/kg Full braking energy absorption with accumulator. Specific Power 0.5 kw/kg 5 kw/kg Unlimited life for accumulator. Efficiency 81% 93% Drive system * Weight - ++ Accumulator also load carrying structure of car. Costs - + Efficiency - + Lower Well-to-Wheel Efficiency, High curb weight. Emissions - + Higher Well-to-Wheel emissions [1] Energy Efficient Hydraulic Hybrid Drives (partial), SICFP 09, Karl-Erik Rydberg, Linköping University, Sweden. * In comparison to Conventional cars
Hydraulic Hybrid The car consists of an independently manufactured, drivable platform and a body of various types. Platform Body Hydraulic Hybrid 283 kg (624 lbs) 250 kg (550 lbs) 533 kg (1,175 lbs) Hydraulic engine charges accumulator Four wheel motors drive & brake the car. Accumulator as load carrying backbone of the car. Active bumper system absorb impact energy from up to 40 mph. Light and spacious body structure. Four-point damper connection to platform. 1,22 L/100km (193 mpg) @ NEDC 33 g/km CO2 2.5 sec (0 62 mph)
Car Concepts Table II: Advanced Car Concepts MAKE Drive System - Mech. Typical Conventional Car Hydraulic energy storage Mech. GM Ultralite VW XL1 Electric Hybrid Tesla S BMW i3 Toyota Prius Electric Electric Electric Hybrid Hydraulic Hybrid Hydraulic Hybrid Length cm 485 420 396 498 399 447 432 Width / Height 183/147 162/129 168/119 196/145 178/157 175/150 178/145 Wheelbase cm 277 280 239 297 259 269 280 Material - Steel aluminum CFRP CFRP magnesium Weight kg 1,540 1,440 635 795 2,108 1,196 1,395 533 Platform/body - - - (485/310) - - - 283/250 Drag Coefficient - 0.28 0.192 0.189 0.24-0.25 0.22 Doors / Seats - 4 / 5 2 / 4 2 / 2 4 / 5 4 / 4 4 / 5 4 / 5 Power kw (hp) 125 170 66/676 90/920 82 111 35/20 47/27 -/265 - /360 -/125 - /170 72/26 98/36 30/355 40/482 Mileage L/100 (mpg) 7.84 30 3.64 65 2.35 100 0.90 260 2.65 89 1.90 124 4.7 50 1.22 193 Travel miles 500 600 - (500) 310 250 600 600 Acceleration 0-60 10 2.5 7.8 11.9 5.4 7,2 10.8 2.5 Cost (MSRP) $ 25,000 - - 125,000 79.900 46,150 26,985 (40,000) Alu. steel CFRP Alu. steel CFRP
Composite Platform Fig. 2: Bumpers on all four sides are automatically extended by 60 cm (2 ) to absorb the crash energy from up to 40 mph hydraulically. The side impact bumpers are not shown. Weight 283 kg
Drivetrain LP Accumulator HP Accumulator Wheel motor Free-piston engine Fig. 3: Free-Piston Engine: 30 kw, 18 kg, compression ratio 35:1, exhaust piston charger & recuperator, bsfc. 140 gr/kw*h Wheel motors (front rear): 120 58 kw, 8.5 6.5 kg, tilt angle 32, planetary gear stage 7:1
Accumulator Assembly Fig. 4: The Standard GFRP assembly with CFRP accumulator (shown) weighs 145 kg. The Advanced version, fully in CFRP weighs 115 kg. (Fluid and fuel not included.)
Accumulator Assembly Fig. 5: Accumulator assembly: 21 parts, 112 kg (246 lbs) CFRP
Platform weight Table III: Platform weights Standard Advanced Standard Advanced kg kg kg kg Accumulator assembly 89.0 77.0 Accumulator 60.0 54.0 Tanks 21.0 17.0 Miscellaneous 8.0 6.0 Hydraulic circuit 53.5 49.5 Tubes, valve blocks 16.5 15.5 Fluid 37.0 34.0 Engine assembly 33.0 31.0 FPE Engine 18.0 16.0 Muffler, intake 5.0 5.0 Fuel (12 Liter / 3.2 gal) 10.0 10.0 Suspension 41.5 29.5 Suspension arms & joints 27.0 17.0 Hydraulic-pneumatic dampening 5.0 5.0 Steering 9.5 7.5 Wheels 64.0 54.0 Wheel motors 32.0 30.0 Rims & tires 32.0 24.0 Bumper system 56.0 38.0 Bumper & shocks (4-sides) 56.0 38.0 Miscellaneous 16.0 14.0 Electronics, battery 8.0 7.0 Generator, pump 8.0 7.0 TOTAL 353.0 293.0 FRP content 43.4% 45.0% By weight, w/o fluids Source: Weights for Platform: CAD data (Valentin Technologies, LLC), Wheels and Miscellaneous: Vehicle Design Strategies to Meet and Exceed PNGV Goals (Rocky Mountain Institute) www.rmi.org
Body weight Table IV: Body weights Standard Advanced Standard Advanced kg kg kg kg Body 164.0 112.0 BIW (Body in White) 111.0 76.0 Doors, closures 53.0 36.0 Glazing 35.0 25.0 Glazing 35.0 25.0 Seats 30.0 24.0 Seats 30.0 24.0 Safety system 15.5 15.5 Air bag system 11.5 11.5 Safety belts 4.0 4.0 Electrical components 21.0 20.0 Lightning, instruments, entertainment, wiring 21.0 20.0 Mech. components 19.5 15.5 HVAC, steering, pedals, wipers, mirrors, locks 19.5 15.5 Interior 18.0 16.0 Interior trim, carpets, foam bolsters 18.0 16.0 Miscellaneous 14.0 12.0 Paint, hardware, fasteners 14.0 12.0 TOTAL 317.0 240.0 Source: Weights for Body: Vehicle Design Strategies to Meet and Exceed PNGV Goals (Rocky Mountain Institute), Costing the Ultralite in Volume Production: Can Advanced Composite Bodies-in-White Be Affordable? (Rocky Mountain Institute) www.rmi.org
Comparison: Weight & Cost Table V: Weight & Cost comparison Cost / Weight Car Conventional Car Standard Composite Hydraulic Hybrid Advanced Cost of production (est.) [1] $10,000 Weight Material Weight Material MSRP (est.) ($40,000) Total Conv. Composites Total Conv. Composites Curb Weight 1,540 kg 670 kg 356 kg 314 kg 533 kg 283 kg 250 kg Material Saved 870 kg 1,007 kg Material Saved + Composites Composites 1184 kg 314 kg 1257 kg 250 kg Material Cost Factor 3.77 5.03 $/kg - conv./comp. material to achieve Cost Effectiveness $6.50 $6.50 $24.50 $6.50 $32.65 $ $2,315 $7,685 $1,840 $8,160 Cost of production (est.) [1] $10,000 $10,000 $10,000 [1] Excluding cost for Electronics
Cost Comparison Conventional Material 1,540 kg Weight Saved 870 kg 670 kg Composites 314 kg Weight Saved 1,007 kg 533 kg Comp. 250 kg Conventional 353 kg Conv. 283 kg Conventional Car Standard Hybrid Hydraulic Hybrid - Weight & Material Advanced Fig. 6: Weight & Material of Conventional car and Standard and Advanced Hydraulic Hybrid Hydraulic Hybrid: Number of parts proportionally reduced to Weight.
Cost: CFRP vs Steel Table VI: Cost CFRP vs Steel Report Rocky Mountain Institute [1] 2013 Verein Deutscher Ingenieure [2] 2013 Roland Berger Strategy Consultants [3] 2012 Part type Engine cradle Seat back Sheet 0.8 x 0.8 m General Material Steel CFRP Steel CFRP Steel CFRP Steel 100% Weight 32 kg 12.7 kg 4.8 kg 1.9 kg 4.5 kg 1.8 kg HS Steel 120 150% Costs $105 $283 $13 $43 $11.30 $63.30 Alu 150 200% Cost/kg $3.30 $22.30 $2.70 $22.70 $2.50 $35.20 Carbon fiber 600 900% Estimates CFRP/Steel Automotive mix 140% Current 570% $35.20 2020 400% $24.70 2030 190% $11.80 Material Cost Factor 283/105 2.7 43/13 3.3 63.30/11.30 44.40/11.30 21.10/11.30 5.6 3.9 1.9 600 900% 140 % 5.4 [1] Kickstarting the Widespread Adoption of Automotive Carbon Fiber Composites. Rocky Mountain Institute, Boulder, CO 80302 www.rmi.org [2] Kohlenstofffaserverstaerkte Kunststoffe im Fahrzeugbau. VDI Ressourceneffizienz GmbH, 10117 Berlin www.ressource-deutschland.de [3] Serienproduktion von hochfesten Faserverbundbauteilen. Roland Berger Strategy Consultants/VDMA, www.rolandberger...
Cost: Platform - Hybrid - Fuel Table VII: Cost CFRP Platform - Hydraulic Hybrid - Fuel 2013 Hydraulic Hybrid Short term 2020 2030 CFRP Cost/lb $35.20 $32.65 $22.70 $24.20 $11.80 Material Cost Factor - 5.6 5.03 3.3 3.9 1.9 CFRP Platform 112 kg $3.950 $3.660 $2.540 $2.710 $1.330 CFRP Car 250 kg $8.800 $8.160 $5.680 $6.180 $2.950 Cost Hydraulic Hybrid 533 kg $10.640 $10.000 $7.520 $8.020 $4.790 Fuel savings (15,000 m, $3.00/gal) $/year $1,260 Combining advanced drivetrain and material technologies allow for reaching the mandatory reduction in fuel consumption and emissions (54.5 mpg, 115 gr/km CO2) in 2025. The outcome of 1.22 L/100 km (193 mpg) with emissions of 33 gr/km CO2 indicates that the further expected reductions beyond 2025 cannot only be reached, but exceeded. In addition, the cost of ownership and safety for the participants are dramatically improved.
CAFE Costs - Fuel Consumption & Emissions TBD.