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Hybrid Buses. Alterno- starter. Battery mode. Serial. In Line parallel. Rear axle Hybridization. Two modes hybrid. A great variety of solutions Compatible with every fuel: diesel- CNG -biofuels Unsure results: from +20% to -25% fuel & CO2 Some disadvantages:
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Hybrid Buses Alterno- starter Battery mode Serial In Line parallel Rear axle Hybridization Two modes hybrid • A great variety of solutions • Compatible with every fuel: diesel- CNG -biofuels • Unsure results: from +20% to -25% fuel & CO2 • Some disadvantages: • Weight +1 ton => less passenger capacity • Reliability? • Safety? • Price, payback, maintenance? Electric Engine Batteries Generator
Hybrid buses : state of the art • Context: CO2 4 factor in 2050 • US Hybrid sales : 2,2% of car sales (07/07) • 1500 US Hybrid buses (3% fleet) 2 technologies : -serial -mixed hybrid Overcost ≈ 100 to 150 000$ Federal Funding 80% • Iveco Irisbus: 14 years of experience Compro
The Irisbus Iveco experience • More than 120 hybrid buses sold since 14 years (de 6 to 12m) London UK Exeter UK Lucca Ital Palermo Ital Aosta Ital Como Ital Trento Ital Siviglia Esp Chieti Ital Biella Ital Citavecchia Ital Campobasso Ital Savona Ital Valencia Esp Torino Ital Genova Ital Terni Ital Ferrara Ital Roma Ital Genova Ital Parma Ital Ferrare Ital Reggio Calabre Ital Napoli Ital Compro
The Irisbus Iveco experience • Main functionalities : • Full electric mode in the city centers • Diesel mode outside of city center • Flexibility • Fuel consumption/noise/emissions Compro
GB converter Aérodynamics 3% 3% Tyres 15% Kinetic energy 43% Idle 8% Auxiliaries 22% Transmission 6% Serial hybrid • High power electronics : 160 to 230 kW • Long chain efficiency : • Lower drivetrain direct efficiency • Very high braking energy recovery • Possible optimization of engine working points through downsizing Compro
GB converter Aérodynamics 3% 3% Tyres 15% Kinetic energy 43% Idle 90 % 90 % 8% 96% Auxiliaries 22% Transmission 6% Mix hybrid • 2 electric engines • More adapted to higher velocities (optimization of engine working points). • Requires a specific GB • stop/start not systematic. 85 % 50 % 98% Storage restitution conversion < 70% 90 % 98% 85 % auxiliaries 85 % 72 % Not systematic Compro
GB converter Aérodynamics 3% 3% Tyres 15% Kinetic energy 43% Idle 8% 96% Auxiliaries 22% Transmission 6% Parallel Hybrid • Example Irisbus Ecodriver • Lower power electronics (80kW on a 12m) • Lean braking energy recovery • Stop start • Still uses a mechanical GB • => High direct efficiency GB 94% Storage restitution 90 % 90 % conversion 85 % 70% Batt 94% auxiliaries 90 % 90 % 85 % Compro
The hydraulic hybrid Caution: hybridization is not systematically made through electricity. Serial and paralell hydraulic hybrid concepts do exist. Compro
How to measure fuel consumption of hybrids? Sort is not a valid cycle for hybrids With SORT consumption reduction is very overestimated - decelerations are too important - braking energy recovery is overestimated => Better rely on real usage test cycles Compro
Synthesis 450 400 350 300 W Fuel 250 % W Mecanical W Wheel 200 150 100 50 0 Mixed Hybrid Conventional Paralell Hybrid Serial Hybrid Source VDV Compro
Energy storage Energy storage possibilities super cap batteries hydraulic Super cap Ŋ=90% 400 kg 50$/kW Cooling by venting Hydraulic Accumulator Ŋ=90% 400kg No cooling necessary Li-ion Ŋ=85% 500kg 70$/kW Cooling by venting NiMH Ŋ=80% 850kg 50$/kW Cooling by venting Lead Ŋ=70% 1500kg 10$/kW Cooling by refrigeration Weight => Capacity Cost Security Reliability Compro
250 200 150 100 CO2 g/km/ passenger 50 0 306 Hdi Bravo JTD Golf Tdi 115 Mégane DTI Astra 2.0 DTI Mégane Dci 406 essence Bus EEV 20 p Bus EEV 75 p Bus Hybride 20p Scenic essence Average car Curb weight and capacity: a key factor • Buses: already a low CO2 transport mode. • 2 to 3 times more efficient than a car • Thanks to its massification effect • Because of its high capacity Picture UITP Compro
Bus Hybrids and CO2 France 2004-2006 Passenger.Km Source: Commission des Comptes des Transports de la Nation • CO2 Potential N°1: Modal shift • CO2 Potential N°2: Hybrids Never forget that: - buses are already a solution to CO2 - the best environmental service a bus technology can provide is to help gaining modal share - operational cost - reliability - capacity Cars 82,9% Bus & Coach 5,1% Rail Transport 10,5% Air Transport 1,5% Compro
Conclusion • A great variety of technologies and unsure results • technologically neutral • => electric • => hydraulic • 100% result oriented (environmental performance) • => external costs? • SORT is not adapted • => evaluation on real usage test cycles • Life cycle cost analysis is necessary • Capacity is a key factor • => performance and cost analyzed per passenger
Thank you for your attention Compro