How to improve hybrid vehicles for environmental sustainability. ATT Conference
ATT Conference Barcelona, October 1-3, 2001 How to improve hybrid vehicles for environmental sustainability. A case study of their impact. Antonio MATTUCCI, Mario CONTE, Giovanni PEDE ENEA – Advanced Energy Technologies Division C.R. Casaccia - Via Anguillarese 301 00060 Rome (Italy) V Incontro Expert Panel Emissioni da Trasporto su Strada 1 ENEA SPECIFIC ACTIVITIES IN TRANSPORT FIELD Among the ENEA interests in the transport field, special attention is paid to the vehicle efficiency and environmental impact; in particular with: Realisation of integrated facilities to assist design and testing of electric and hybrid vehicles and specific components of the traction system Fleet tests under operational conditions of hybrid vehicles Fuel cells and H2 Program V Incontro Expert Panel Emissioni da Trasporto su Strada 2 Vehicle drivetrain integrated testing facility The main parts of the facility, interconnected each other in order to provide high test flexibility , are: Power generation section Energy storage section Driving motors section Integrated control room V Incontro Expert Panel Emissioni da Trasporto su Strada 3 Fleet test of hybrid vehicles Public transport fleets have been tested in three selected cities, where 24 IVECO 490 buses have been purchased and operated for 3 year (1997-1999) 4 in Terni 8 in Ferrara 12 in Rome V Incontro Expert Panel Emissioni da Trasporto su Strada 4 Fleet test of hybrid vehicles IVECO 490 hybrid bus characteristics 2.8 l diesel engine 30 kW DC electric generator 164 kW AC electric motor 60 kWh capacity lead acid batteries 200-300 km range of in thermal mode and 20 km in pure electric mode 60 km/h max speed manual selection of driving mode V Incontro Expert Panel Emissioni da Trasporto su Strada 5 Fleet test of hybrid vehicles Hybrid and conventional bus test results Vehicle EURO II Bus Series Hybrid Bus Fuel Consumption (L/km) CO specific emissions (g/km) VOC specific NOx specific emissions emissions (g/km) (g/km) 0.437 5.05 0.82 24.92 0.41 0.3 0.59 11.55 Need of a control system to increase hybrid vehicle efficiency V Incontro Expert Panel Emissioni da Trasporto su Strada 6 Hybrid vehicle control system framework Series hybrid vehicle fuel consumption dependent on battery State Of Charge (SOC) and generator power Test campaign to get additional information on hybrid specific consumption, using a purpose-designed series hybrid vehicle with the same driveline of 6m ALTROBUS Control strategy constrains the battery SOC to stay in a selected interval and allows modifications of the thermal engine working point, with variations in a range of 20-25%, as in such interval the environmental and energetic efficiency remains high V Incontro Expert Panel Emissioni da Trasporto su Strada 7 Hybrid vehicle driveline characteristics Internal combustion engine 1.2 l diesel engine 24 kW max power (@ 3600 rpm) 2200 rpm rating speed Synchronous PM Machine 10 kW rating power (@ 2200 rpm) Storage system (battery) 96 lead acid cells 100 Ah capacity, 192 V V Incontro Expert Panel Emissioni da Trasporto su Strada 8 IVECO Daily hybrid vehicle layout Electric Propulsion System Brake Fuel Accelerator P=K ICE Wheel Controller AC Generator Generation System Battery Charger DC/DC DC Chopper Motor Gear Battery Pack V Incontro Expert Panel Emissioni da Trasporto su Strada Wheel 9 Hybrid vehicle DC source behaviour Specific Consumption rpm Ps = variable-speed, minimum-consumption curve V Incontro Expert Panel Emissioni da Trasporto su Strada 10 Daily hybrid vehicle controller development Low cost controller, 200 ms. sampling time Step by step controller development Final controller version based on a forecast of the power required (based on previous average power + trip route) Controller algorithm processes data related to battery voltage, current and SOC First controller version has no power forecast and requires manual setting of: generator power and SOC interval limits Controller switches on-off the thermal engine to keep the battery SOC between predefined limits Controller effectiveness verified by means of many tests based on European, American and Japanese cycles V Incontro Expert Panel Emissioni da Trasporto su Strada 11 Daily hybrid vehicle test results Driving cycle / Main parameters Unit Driven distance Km Average traction power W Total traction energy Battery charge/depletion SOC (depletion is positive) Diesel fuel consumption European Cycle (ECE/NEDC) 28.89 Japanese Cycle (1015) American Cycle (UDDS) 19.80 26.96 7251 7370 9140 Wh 11384 9212 10785 W -1.50 -1.20 5.80 Ah -1.05 -0.84 4.06 Wh -201.60 -161.28 779.52 kg 3.99 3.08 3.16 Wh 46765 36060 37085 1618.74 1821.26 1375.59 15.7 17.5 12.5 Wh/km Equivalent fuel L/100 km consumption V Incontro Expert Panel Emissioni da Trasporto su Strada 12 Effectiveness of hybrid vehicle controller Testing on the vehicle has shown the following results: Considerable improvement on fuel efficiency achieved, especially for the American cycle Important to minimise start/stops of the thermal engine Next step with thermal engine load prediction requires more sophistication for the control algorithm Need to modify the thermal engine working point (power and speed) to gain additional efficiency 30-40% of fuel consumption reduction achievable, with similar benefits in terms of pollutant emission reduction V Incontro Expert Panel Emissioni da Trasporto su Strada 13 Requirements for hybrid vehicle fleet deployment effectiveness analysis Main requirements Identification of effective application domains, where hybrid vehicles can play a special role Measurability of resulting effects at global scale Different effects (such as pollutant emissions, fuel consumption and even the resulting traffic conditions) to be considered at the same time Identification of economically and technically affordable deployment experiences Identification of appropriate analysis tools in order to simulate the resulting scenario Use of conservative assumptions where sound information is lacking V Incontro Expert Panel Emissioni da Trasporto su Strada 14 LDVs viability for hybrid vehicle fleet deployment application Initial considerations Light Duty Vehicles (LDVs) cover approximately 5% of the Italian fleet (2 millions of vehicles) LDVs cover the main share of freight transport in urban areas LDVs are responsible of relevant shares of pollutant emissions in urban areas Results of ENEA hybrid vehicle experimental test campaign fit perfectly LDVs behaviour TREMOVE model and reliable database are already available for a deployment study V Incontro Expert Panel Emissioni da Trasporto su Strada 15 Share of LDVs pollutant emission in Italian urban areas Impact of LDV in urban areas (year 2000) 8.6% 10.4% 4.3% CO 10.4% FC NOx 0.7% 13.8% PM C6H6 VOC NMVOC 3.5% CH4 28.8% 6.5% SO2 N2O CO2 6.4% 6.5% V Incontro Expert Panel Emissioni da Trasporto su Strada 16 Hybrid LDVs reduction factors for impact analysis Reduction factors Indicators Gasoline LDV Diesel LDV CO emission 0.7 0.1 NOx emission 0.7 0.5 VOC emission 0.7 0.7 PM emission 1.0 0.6 Fuel consumption 0.9 0.9 V Incontro Expert Panel Emissioni da Trasporto su Strada 17 LDVs behaviour Fuel specific consumption for Light Duty vehicles 180 160 Conventional Gasoline LDV 140 Euro IV Gasoline LDV g/km 120 100 Hybrid Euro IV Gasoline LDV 80 Conventional Diesel LDV 60 40 Euro IV Diesel LDV 20 Hybrid Euro IV Diesel LDV 0 10 15 20 25 30 35 40 45 50 55 60 65 70 Vehicle average speed (km/h) V Incontro Expert Panel Emissioni da Trasporto su Strada 18 LDVs behaviour CO specific emissions for Light Duty vehicles Conventional Gasoline LDV 50 45 Euro IV Gasoline LDV 40 g/km 35 Hybrid Euro IV Gasoline LDV 30 25 Conventional Diesel LDV 20 15 Euro IV Diesel LDV 10 5 0 10 15 20 25 30 35 40 45 50 55 60 65 70 Hybrid Euro IV Diesel LDV Vehicle average speed (km/h) V Incontro Expert Panel Emissioni da Trasporto su Strada 19 Hybrid LDVs urban deployment study Milan city selected for the analysis 142000 LDVs operating in Milan area Introduction of hybrid LDVs begins in year 2002 The shares of new hybrid LDVs covers 20% in the year 2002, 55% in 2003 and 100% in 2004 and beyond Total extra-cost in 2002-2005 is about 174 MEuros, of which 12 in the year 2002 (2000 new LDVs deployed) Two scenarios have been analysed with TREMOVE model, the first one only with hybrid introduction and the second one with also the integration of telematic systems to improve freight delivery effectiveness V Incontro Expert Panel Emissioni da Trasporto su Strada 20 Hybrid LDVs first scenario results Years 2002 2003 2004 2005 2006 2007 2008 2009 2010 0.00% -1.00% Emission Reduction (%) to reference basecase shows relevant differences only on emissions Considerable effect specially on PM ( 5%) After 2008 no more PM reduction as almost all the oldest and dirtiest LDVs have been removed Impact of series hybrid LDV in Milan Comparison -2.00% -3.00% -4.00% CO FC NOx PM VOC CO2 -5.00% -6.00% V Incontro Expert Panel Emissioni da Trasporto su Strada 21 Hybrid LDVs second scenario results Two Impact of hybrid LDVs introduction in Milan: load increase scenario 2010 2009 2008 2007 2006 2005 2004 2003 2002 years 0% -2% -4% Reduction (%) beneficial effects, i.e. direct reduction of emissions and increase of commercial speed, respect to reference basecase Relevant decrease of all the pollutants ( >5%) Higher effects on fuel consumption, CO2 and CO emission -6% CO NOx PM -8% C6H6 -10% -12% -14% VOC FC -16% CO2 -18% V Incontro Expert Panel Emissioni da Trasporto su Strada 22 Conclusions Fleet tests of hybrid vehicles have shown positive performances and provided information for the fields where additional research is required Series hybrid vehicles can be improved by the adoption of a control system able to manage the battery SOC and the thermal engine working point Series hybrid vehicles can provide good results for applications in domains where both the vehicle efficiency and emission reduction are to be considered The combination of hybrid technology with other provisions (technological, legislative, informative, etc.) can provide very important additional benefits V Incontro Expert Panel Emissioni da Trasporto su Strada 23
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