Comparisons of commercial electric bus performance, first results

Transcription

1 VTT TECHNICAL RESEARCH CENTRE OF FINLAND LTD Comparisons of commercial electric bus performance, first results ECV National Seminar Teemu Halmeaho VTT Technical Research Centre of Finland

2 Outline Background and aim ebus fleet Testing method Results Conclusions 16/10/2015 2

3 Research question and aim of the study Research question Aim Commensurable public information on electric city bus performance not available yet Are there any differences in performance of electric city buses? What is the energy consumption of an average electric city bus? To compare performance of different electric buses using method that is commensurable 16/10/2015 3

4 ebus fleet All the buses (except Muuli) have been leased and operated by Transdev Finland Transdev Finland had a key role in starting ebus project Gaining experience on electric buses in actual operation environment Fully electric 12 meter buses 16/10/2015 4

5 Caetano Cobus 2500 EL Portugal, autumn 2012 Battery capacity 150 kwh Nominal motor power 150 kw Drive Front wheel, two gears 16/10/2015 5

6 Muuli Finland, autumn 2012 Battery capacity 56 kwh Nominal motor power 207 kw Drive Rear wheel drive 16/10/2015 6

7 Ebusco YTP-1 Holland (China), end of 2013 Battery capacity 242 kwh Nominal motor power 150 kw Drive Rear wheel drive 16/10/2015 7

8 VDL Citea Electric Holland, summer 2014 Battery capacity 85 kwh Nominal motor power Drive 2x 113 kw Rear inwheel motors 16/10/2015 8

9 BYD ebus Green City China, summer 2014 Battery capacity 324 kwh Nominal motor power Drive 2x 75 kw Rear inwheel motors, hub gears 16/10/2015 9

10 Ebusco 2.0 Holland, spring 2015 Battery capacity 311 kwh Nominal motor power 150 kw Drive Rear wheel drive 16/10/

11 Summary of the general specifications Battery (kwh) Power nom (kw) Drive Caetano Muuli Ebusco VDL BYD Ebusco LFP 56 LFP 242 LFP 85 LFP 324 LFP 311 LFP FWD, two gears RWD RWD RWD inwheel RWD inwheel, hub gear RWD 16/10/

12 Principal of the measurement method Using a chassis dynamometer that simulates the vehicle weight and driving resistances during on-road operation 16/10/

13 Testing method To study the performance under different operation conditions, driving cycle and amount of passengers is varied Five different cycles (bus lines) Espoo Line 11, Braunschweig, London, New York, Ademe Three payloads kg, kg, full load Battery capacity test 16/10/

14 Results Line 11 and Braunschweig kg payload kg payload Line 11 Braunschweig kg kg kg kg Average (kwh/km) Lowest (%) Highest (%) Diesel bus /10/

15 Remarks on energy consumption in electric buses In + direction Vehicle mass and component efficiencies In direction, capability to regenerate kinetic energy is affected by Vehicle mass Increases the kinetic energy Powertrain component efficiencies Battery recharging power is rather low in LFP batteries Capacity increases power Sensitive to battery temperature Braking control Pure rear wheel braking causes stability issues 16/10/

16 Remarks from production capacity point of view Increase in consumption for kg increase in payload (14 => 42 passengers), Line 11: Also the passenger capacity is higher in some buses Line 11, full payload: Some buses had higher battery capacity providing all day operation without re-charging Range in Line 11 (dyno), 1000 kg payload: Average increase % 13 Min increase % 7 Max increase % 17 Average (kwh/km/pass_ton) 0.20 Lowest (%) -37 Highest (%) 47 Average range (km) 267 Lowest (%) -58 Highest (%) 54 16/10/

17 Summary Differences were found amongst the tested buses On paper 12 m city buses Implementations vary, which affects the performance Average consumption in dyno conditions 1.15 kwh/km (Braunschweig cycle with kg payload) During on-road operation, auxiliary components would be more active (about 0.1 kwh/km) HVAC would at this even more (8 kw thermal => 0.23 kwh/km) Battery regeneration power is lower in cold conditions How to benefit the key findings? Measured consumption value (by independent party) now available to be used in decision making internationally Involved bus manufacturers have gained data for R&D leading into more energy efficient electric buses in the future 16/10/

18 TECHNOLOGY FOR BUSINESS