Decreasing Energy Consumption and CO 2 Emissions in Urban Vehicles Hybridation and engine downsizing integrated with mission oriented design Nuno Manuel Ferreira Teixeira Fernandes Resumo da Dissertação para a obtenção do Grau de Mestre em Engenharia Mecânica Júri Presidente: Prof. Ramiro Neves Orientador: Prof. António Luis Moreira Vogal: Prof. Tiago Farias Outubro, 2007
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Decreasing Energy Consumption and CO2 Emissions in Urban Vehicles
Hybridation and engine downsizing integrated with mission oriented design
Nuno Manuel Ferreira Teixeira Fernandes
Resumo da Dissertação para a obtenção do Grau de Mestre em Engenharia Mecânica
Júri Presidente: Prof. Ramiro Neves Orientador: Prof. António Luis Moreira Vogal: Prof. Tiago Farias
Today’s cities face many problems, transportation being one of the most relevant. Mobility in cities creates problems of congestion, energy consumption, pollutant emissions, and last but not least of health and safety. Attempts made so far to have a cleaner mobility, based on low polluting vehicles, have been successful in demonstrating the concept but have failed to start a real market for non‐polluting vehicles. To give a fighting chance to Low Polluting Vehicles their versatility must be enhanced and their costs lowered. They also have to stand up to customer expectations, competing against conventional vehicles on the supply side (who is granting the service) and the demand side (customers acknowledgement of the vehicles’s advantages). To this aim the EC funded an initiative on sustainable mobility, called HOST–Human Oriented Sustainable Transport.
HOST is a vehicle equipped with a modular chassis able to extend or retract in a range that allows it to operate as a medium city car or a small truck (from 3.5 to 6 m length). Some flexibility is also allowed to its gross weight which spans from 2 to 4,5 tons. The HOST Powertrain is modular because it houses different propulsion modules, all of which must
be designed as “black boxes” in order to be taken away or added to the vehicle according to its towing requirements. The vehicle body can also be modified to suit different services, which include: Collective taxi, Car‐sharing services, Freight collection and distribution and Garbage collection. Propulsion employs a four wheel steering configuration which enables the vehicle to turn around its vertical axis as well as horizontal shifting. In HOST drive‐by‐wire technology is not a choice but a must, since powertrain modularity so demands. The elimination of the mechanical steering connections eases the cabin changing operations. The complete steering capabilities of the 4 wheels render driving them with a conventional mechanical system almost impossible. Also the layout of 1 electric motor per wheel renders unfruitful all efforts to mechanically interconnect the wheels during either traction or braking. The drive by wire system allows the movement of the command console, allowing good visibility characteristics during turning in tight environments (e.g. warehouses or freight centres).
Missions
Mission 1 ‐ “Algés quase de lés a lés” is a free of charge transport of passengers, operating in Algés, oriented for the special needs of the elder public. The service laps a round trip around the council in a route with over 4Km, in a mini‐bus with dimensions tailored for narrow streets. The conceivable alternative being a taxi, this mission is a Collective Taxi service. Mission 2 ‐ A garbage collection service it collects yard waste and large/bulky rubbish. Pickup occurs upon request and hence the driving route varies. The garbage is disposed outside the urban area and so the road includes non‐urban parts. The average speed while moving is 20km/h, but stops are so frequent that overall speed is less than 10 km/h. This was the only mission measured for the garbage recovery service of HOST. Mission 3 ‐ The third service is a transport of young handicapped people with low economic resources. Despite the bus always returning to the point of departure, the driver is free to alter the route according to the
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Mission 2 Mission 3 Mission 1
traffic, unlike mission 1. It is the mission with the highest average speed and yielding the least time spent at idle. It is also part of the collective taxi service.
Data Collection
Because weight and aerodynamic characteristics are independent from the road being travelled (the tyre friction is dependent on the tarmac surface) the instantaneous power and energy requirements of a vehicle require only the instantaneous slope and speed measurement. Both speed and slope can be collected with a
GPS, but the presence of an urban environment creates many difficulties to the GPS systems, most of them connected to errors due to signal interference but also due to the passage under bridges and the fact that slope depends upon altitude, a measurement whose associated error is usually about twice as large as location. Hence, although 2 GPS systems were acquired, a “cheap” GPS
system from Haicom and a more expensive DGPS system from Geneq (SX Blue), only one proved good enough for data registration, as can be seen by the graph. An accuracy assessment was performed comparing both GPS systems against topographic military charts. As the graph shows the performance of the DGPS system, in altitude measurement, proved vastly superior to the Haicom system. The main components of power required to move the vehicle are presented below. From these equations in‐cycle power requirements where calculated:
)/((%))( smVGradeNWPSlope ××= (1) allowing for a simplification considering small slopes, tan (θ)=( θ)
)/()( smVRNWP rollingTyre ××= (2)
xfrontalairAero CAsmVP ×××= ρ5,0)/( 3
(3)
)/()/()( 2
. smVsmaKgMP longAccel ××= (4)
Measurement results
Average Required Power ‐ Performed in a round circuit, in mission 1 only speed and the number of passengers vary. The average speed is very small explaining a small average power and the fact that in this mission the number of passengers (and hence weight) is negatively correlated with the instantaneous speed means that both factors cancel out reducing results variance. The larger average power required by mission 2 is
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due to the fact that the route is not constant and includes non‐urban roads where average speeds go up to 30‐40Km/h, or even short highway commuting. Mission 3 requires the largest average power due to its almost entirely non‐urban cycle that even includes a highway part, which more than compensates the smaller weight of this vehicle configuration and the calm driving behaviour of its driver.
The maximum average power measured in Oeiras is under 8kW but after the addition of the cycles measured
elsewhere (car‐sharing in Rome and freight in Stockholm) a value of 9kW for propulsion was agreed; still, after adding the power required for simultaneous operation of vehicle auxiliaries this value grows to 14kW.
Hybrid Powertrain
Hybrid Powertrain architectures
HEV‐P, or a parallel hybrid vehicles; HEV‐S, or series hybrid vehicles; Parallel and Series hybrid vehicles.
Most (if not all) hybrid powertrains able to operate in parallel and series simultaneous configuration are property of major automobile manufacturers, and hence this configuration is almost impossible to obtain as an already developed system; hence our simulations focused on the less complex (and possible to adapt to HOST) HEV‐P and HEV‐S configurations. HEV‐P refers to a powertrain architecture in which both the electric motor and the engine drive the wheels, without possibility of the combustion engine being linked directly to electric devices or the electrical motor supplying propulsive power on its own. The 2006 Honda Civic Hybrid is an example of such a configuration. On the other hand in an HEV‐S the ICE never powers the wheels. Either fitted with in‐wheel motors or with just one central electric motor it is always the latter who makes the vehicle move. The ICE is connected directly to the generator, working at constant and optimum conditions to supply energy to the wheels and/or to the batteries. Vehicle Range, the main concern of all electrical vehicles, is not problematic due to the presence of an ICE to recharge the batteries.
Hybridation Strategies
In the follow‐up strategy energy is produced at the ICE‐generator assembly according to the energy spent at the wheels some moments earlier. In fact, the electronic power controller registers the energy drain from the batteries for a period of n seconds and then regulates the ICE to produce, for a period of y seconds, the same amount of energy that was during the above mentioned period. Its biggest advantage is that almost all energy produced by‐passes the batteries as we accept to lose efficiency in the ICE in order to gain efficiency in the hybrid system. It also avoids constant ICE start‐stop hence avoiding also cold start periods in which pollutant emission is significant. The reservoir strategy is less complex. The batteries are seen as a reservoir with a minimum threshold and a maximum threshold usually set to the values that maximize battery life and its charging and discharging efficiencies. The electronic power controller again records the energy requirements at the wheels and asks for this energy to be supplied by the batteries. Whenever the battery charging level reaches the minimum threshold the ICE is put to work at optimum efficiency. In our ADVISOR simulations this was precisely the strategy employed with the ICE producing energy always at maximum efficiency conditions.
Max. Thermal Power Car Sharing Freight Garbage Collective TaxiCycle 9.0 kW 9.0 kW 9.0 kW 9.0 kW
In the table shown, results the HEV‐S configuration always yields the lowest fuel consumption regardless of mission and/or measurement. As was expected cycles with slightly higher average speeds and less time spent at idle yielded the lowest difference between the HEV‐S and HEV‐P, the case of mission 3. Even the conventional powertrain
yielded what can be considered a good result taking into consideration the frontal area of the vehicle and the 3,5 ton weight. On average the highest differences were recorded on the garbage recovery cycles, in which idle time sometimes reached more than half of the cycle’s duration. Another interesting feature from the comparison is the little variance of the fuel consumption values for the HEV‐S Powertrain. Although expectable because the internal combustion engine operates almost always at its peak efficiency, the difference in fuel consumption, between the extremes, was just under 50% while the energy spent per cycle varied slightly more. It is nevertheless necessary to remember that the energy produced at the generator can go to the wheels or be forced to pass through the batteries with different efficiencies involved. The HEV‐P configuration exhibits higher consumption as it doesn’t adapt so well to slow in‐city cycles. Concluding, to say that regardless of the mission, hybridation decreases fuel consumption significantly seems fair and the HEV‐S configuration seems especially well adapted to in‐town driving. Hence it was chosen to equip HOST’s prototype.
Engine Choice
To choose the internal combustion engine for HOST, a benchmark analysis was conducted to evaluate available ICE’s from the automotive industry (need for EU4 compliance).
Benchmark: Efficiency & Emissions
The main criterion for the evaluation on this specific parameter was the adjusted fuel consumption and its correspondent adjusted CO2 emission. The adjusted fuel consumption was calculated defining how much fuel a “1000kg equivalent vehicle” would need to perform the NEDC cycle. As an example,
this explains why both Smart engines present the highest adjusted fuel consumption, even though both use less 1 Net energy spent per each 30 minutes of cycle for propulsion requirements only, for comparability reasons. 2 HEV‐P Powertrain control strategy employed was that of the Honda Insight available in ADVISOR.
Mission 1 (simulated at 3500kg)Cycle Characteristics Fuel Consumption (L/100km)Cycles
Speed Var. % time (idle) Energy1 (kWh) ICE HEV ‐ S HEV ‐ P2
Combined Fuel Consumption, (weight adj.) [ l /(100km*ton)]
Combined CO2 emissions, (weight adj.) [g/(km*ton)]
1.0 L 5.8 138
1.0 L 5.5 132 0.6 L 6.4 155
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fuel on absolute terms. On an adjusted approach we can see that the Smart engine, which at first sight looked to be the best performer, is slightly outperformed by its competitors. While the difference is truly negligible for the Diesel engine case, it is significant for the gasoline engine.
Benchmark: Performance in Power Interval
All diesel engines are direct injection, turbo‐charged engines, fitted with intercoolers. The compression ratios range from 19.5 to 18 and unitary displacement from the 266cm3 per cylinder of
the Smart For2 engine to 533cm3 for the Smart For4. Hence both the 0.8CDi engine (3 cylinders) and the 1.3CDTi (4 cylinders) will suffer increased thermal losses and reduced fuel efficiency. Amongst the gasoline engines all are IDI. The maximum torque figures are higher in the diesel engines, and this is an advantage since it can provide similar amounts of power at lower engine speeds. For the power interval required in HOST, if gasoline engines are to work at maximum torque engine speeds the load they require is too low and this greatly impacts the specific fuel consumption (SFC). In fact only the Smart 0.7L gasoline engine escapes this logic due to the presence of a turbo‐charger. Nevertheless its overall efficiency is below that of a diesel and also that of its gasoline competitors, when comparing best overall SFC’s. As expected the diesel engine outperfm their gasoline competitors clearly. In particular the Smart diesel engine shines, not due to its performance in the upper power extreme of the interval but mainly on the low power interval.
Benchmark: Packaging
The Packaging evaluation focused on engine weight and engine bulk dimensions. Road‐use engines’ dimensions are usually not published, leading us to need to estimate length and weight, deemed the most pertinent constraints in HOST’s packaging. Results for weight were obtained from
correlations in which weight varies with displacement, while length was estimated from the knowledge (or the estimation itself) of parameters such as the number of cylinders, the bore and stroke dimensions, the cylinder wall thickness, the spacing between cylinders the length required for the chains/belts and the overall length of the clutch bell house. Results show the clear advantage of gasoline engines in both weight and length, with the non‐turbo gasoline engines presenting even smaller weights and dimensions. Both smart engines present good packaging characteristics but the diesel one displays one of the lightest weights combines with a length that is almost on pair with that of the gasoline engines.
Choice of “Best in Class”
Overall the engine choosen to equip HOST was the Smart 0.8CDi engine. Providing the one of the best mixes of efficiency, cleanliness and performance it loses only (and slightly) in the packaging area versus gasoline engines, but not enough to outshine its main advantages. To us it represented the best compromise.
1.5 CDI 3 83 x 92 132.5 Kg ~ 520‐530 0.8 CDI 3 65.5 x 79 70 Kg 460
Gasoline # Cyl. Bore x Stroke Weight Length ( in mm)
1.0L‐Toyota 3 71 x 84 ≈ 60‐65 Kg ~ 400‐4101.0L‐Opel 3 73.4 x 78.6 ≈ 60‐65 Kg ~ 400‐410 0.7L‐Smart 3 66.5 x 67 60 Kg ~ 410‐420
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220g/kWh230g/kWh 230g/kWh ≈245g/kWh245g/kWh
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HOST’s ICE Operating Strategy
It is evident from the graph shown left that the lowest SFC is achieved at lower engine speeds and higher loads (when comparing similar power requirements). This comes as no surprise since it is known that the most economical way of driving is (almost always) to use lower engine speeds and higher torque loads (for similar amounts of power). Being a series hybrid vehicle HOST is fitted with an electrical generator, and in order to minimize the work to be imposed at the control
unit the best operating strategy for HOST would be to operate varying only load or, alternatively engine speed. Still it was deemed easier to impose the load on the generator and change only load. This strategy also delivered the best results for efficiency especially taking into account the need to operate at reservoir strategy (15kW) or at follow up strategy (4‐10kW needed). Here the engine’s own natural characteristics came to our help since the engine’s best SFC can be produced at nearly constant rpm, from 1800 to 2000rpm, as can be seen form the graph above. The simulated engine operating map can be seen in the graph presented on the right. It yields results between 217.5 and 280g per kWh for all of HOST’s operating requirements.
Biofuels Overview
Bio‐Ethanol is a simple molecule (C2H5OH) which, due to the presence of the OH radical, is an oxygenated fuel, and if generated from biomass is called bioethanol. Although specific mass, at 790g/dm3, is on pair with fossil fuels, it has 40% less energy per unit of weight than gasoline. This introduces major concerns of range and even dedicated E100 ethanol engines, which provide considerable performance gains, due to the high RON of the fuel (108) and the much higher heat of vaporization, cannot completely solve. Nevertheless these characteristics render it perfect for turbo‐charger applications also because of the reduced cost difference compared to gasoline engines. When they operate in places with an existing ethanol infrastructure, they lower operating costs. Biodiesel refers to oil (RME for example is C19H36O2), derived from biomass sources, with suitable characteristics for burning in compression ignition engines. Modern compression ignition engines require low kinematic viscosity oils and a cetane number over 49 to guarantee smooth combustion and good lubricity. It has a reduced energetic content per unit of weight, circa 38000kJ/kg, but makes up for it being heavier than common diesel. Hence range is almost not affected. In terms of emissions performance, it is an improvement versus diesel except for NOx which usually increases slightly. Nevertheless its greatest downfall is cold weather start performance which is usually solved only by adding a small amount of fossil diesel. Biogas is the biofuel equivalent of Compressed Natural Gas usually derived from un‐decomposed bio‐mass, one of the best uses for bio‐waste as it generates energy while reducing GHG emissions due to the use of the CH4 that would otherwise be released. Methane, its main compound, has a very high energetic density, per mass, at 49.900kJ/kg, but is very light at ambient pressure and temperature, requiring compression to pressures
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0 1 2 3 4 5 6 7 8 9
Wheat
Corn
Sugar beet
Switchgrass
Miscanthus
Sorghum
Sugarcane
Energy Ratio for various Ethanol Crops
0 1 2 3 4 5 6 7 8 9 10
Peanut
Soy
Crambe
Rape Seeds
Sunflower
Jatropha
Dende Oil
Palm Oil
Energy Ratio for various Biodiesel Crops
Fossil Fuels
Bio-m
ethane
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Bio-ethanol
-150 -100 -50 0 50 100 150 200
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Gasoline PISI
Farmed Wood
Wheat, no straw
Wheat, with straw
Sugarbeet
Sugar Cane
Sunflower
Rape Methil
Rape Ethil
Dry Manure
Liquid Manure
USW
WTW GHG Analysis
around 350 bar to yield sufficient range for road vehicles. Dedicated biogas engines have a huge potential since the fuel’s octane rating is over 120. Its gaseous nature gives it good cold starting abilities and low emissions.
Biofuels as Sustainable Alternatives
Energy Ratio
Biofuels will only be worth considering if they can yield more energy from the burning that they required to be grown (excluding the sun’s input). This measured by the amount of energy extractable from the biofuel, divided by “man’s input energy to grow it” which is called the energy ratio and has to be greater than 1. Numbers on energy ratio differ from biofuel to biofuel and even from crop to crop. Also of utmost relevance is the consideration given to by‐products usage. Biodiesel seems to be at an
advantage as almost all crops yield at least an energy ratio of 2. Palm and Dende oil present good performances but generate much concern about soil erosion. Jatropha is likely to be a major contender since it can be grown almost anywhere and has a very positive energy ratio. Sunflower and Rape have lower performances but only Soy crops have reduced energy ratios and peanut crops are only shown for comparison reasons since its economical value is too high to render it profitable as an energy culture. The outlook seems grimmer from the point of view of bioethanol since both sugarbeets and corn require by‐products usage to present greater than 1 energy ratios and wheat, without by‐product credits is energy destructive (takes more energy to grow than it releases through burning). Miscanthus and Sorghum perform well, while Brazilian sugarcane has been proving a great source of energy since long.
GHG Emissions
The figure shown is evidence that the selected bio‐fuels in our comparison can reduce GHG emissions. Because the TTW analysis varies little, the comparison shown is largely a product of the WTT phase variation. The case for bio‐ethanol is largely favorable, except for wheat. Sugar beet seems
to deliver good results and sugar cane performs even better. Farmed wood for bio‐ethanol shows encouraging results, but its use for biogas production might be just as efficient or even more. The case for biogas is even stronger. First, it provides a clear advantage in the TTW part of the cycle, being capable of substantial reductions on CO2 emission at the tail pipe. But, furthermore, it also performs well in the WTT phase and it is the alternative with the highest reduction in the combined WTW emissions. Both USW and dry manure are easily capable of outperforming both the bio‐ethanol and bio‐diesel. The case for bio‐diesel is not as bright, especially if the traditional food competitive crops are used. This is the case for Rape Seeds and, although not represented, it is even more the case for Soybeans. The only culture capable of reductions around 60‐75% is sunflower. In Europe, the production of biodiesel from crops as Jatropha offers a much better potential.
Biofuels as Prime Movers
To be a prime mover a bio‐fuel must have an energetic yield per unit of area which could render possible the fueling of the transportation system from these proceedings. The numbers presented in the graphs should be seen as theoretical limits, but they demonstrate that, at least in regions of the world with high population
densities and low arable percentages of land, biofuels cannot provide a real alternative to fossil fuels as, even using all arable land available to produce them we could not fuel our transportation system. Only countries such as Brazil and or China might have enough land to accomplish this. The percentage shown in the bars refers to the percentage of Germany’s arable land required to substitute 20% of its transportation requirements.
Looking at the graph we see that most biofuels fail to reach 40,000km/year per each hectare of land. Only a couple manages to reach 45% and only Miscanthus has a strong yield. It is important to notice that implicit in the mathematics is a 10,5L/100km fuel consumption of bioethanol which is not a high value. The case for Bio‐
diesel is slightly more complicated as, of all the crops presented above, only Rape, Jatropha and Sunflower can be produced in Europe. Palm and Dende Oil are typical of rainforest areas and hence cannot be grown in Europe. Rape, despite having the 2nd lowest yield, is by far the most common crop for bio‐diesel production in Europe, while Soy, with a yield of less than 7.500km of annual driving per ha, is not even represented. The most common crop in Europe, Rape seed, needs almost
37% of all arable land to achieve such a substitution rate and sunflower seems to perform only slightly better. The results are inferior to those of Bioethanol, mainly due to the fact that the crops with high yields can not be planted in Europe and much doubt remains over their long term sustainability. Jatropha appears once again as a promising alternative. The difference in the case of biogas is the absence of a crop as only biomass wastes, such as wood wastes or Urban Solid Waste is used. Estimates indicate that, in Europe, biomass could provide up to 11% of total energy
consumption. Currently, less than ¼ of that total potential is being explored. In California, if all the biomass potential could be explored 2.4 million tons of methane per year would be produced, still granting a substitution rate inferior to 6%. Bio‐methane generated from cow manure is another option. A possible way to present its yield is to show how many annual kilometers can be traveled, by taking advantage of the yearly
manure production of 10 cows; the answer is around 36.000km per year. Still, if this was applied to Germany and all the cow manure could be used to generate biogas, the substitution rate for road transport would be of no more than 3.1%. Similar calculations can be performed for USW. Each 100 persons generate enough to propel a vehicle for more than 60.000km a year. But if all USW was used for biogas production the substitution rate would be around 10%.
ADVISOR Simulations
After the analysis of the biofuels performed above it was decided to investigate HOST’s performance if fitted with a biofuel engine. Because the Smart 0.8CDi is fitted into HOST’s prototype the analysis of the biofuel adaptability was theoretical. Nevertheless because the Smart gasoline engine could be adapted to bioethanol use without major changes, the benchmark performed above holds for packaging and cleanliness has it would
be EU4 compliant. Only efficiency had to estimated and hence dedicated engines for bioethanol, biodiesel and biogas were simulated. It is important to state that real‐life conversions for bioethanol and biogas, based on this engine, have been performed. The theoretical maximum efficiencies estimated for all engines are presented on the left and were based on results known from IFP articles. In our theoretical calculations, we took our downsizing strategy even further (500cm3 are enough for biogas and bioethanol) and we also simulated 2 changes which the IFP did not perform:
Direct fuel Injection and turbo‐charger swapping for a lower inertia unit, with maximum torque coming at lower engine rpm. In the end the advisor simulations presented next were performed with the bioethanol version, due to the range problem of biogas, and the superior properties of bioethanol, compared to biodiesel.
ADVISOR Results
Here we can see the huge potential of this hybridation technology. For mission 3 cycles the combined WTW GHG emissions are actually inside the EU target, and although outside for the 2 remaining cycles, they are still very close to the limit and represents a huge reduction vs.
the 820g/CO2 per km estimated to be emitted by the vehicle currently performing the cycles.
The results for the homologation cycle yielded 18.2 liters of ethanol for the NEDC low cycle, containing the same energy as 10.5 liters of diesel, a significant result due to the comparability of homologation cycles. To allow fairer comparisons we provide figures for the FTP cycle (USA). The consumption achieved (19,7L/100km) equals 13,1L/100km of gasoline, or 18,5 miles per gallon in Anglo‐Saxon units. The hybrid Lexus RX400h SUV has a fuel consumption of 24 miles to the gallon in the FTP cycle, despite weighting half as much as HOST’s Cabin configuration and having an Scx of only 45% of HOST’s.
The reduction obtained in the car‐sharing configuration amounts to about 47%, when compared with the cabin configuration for comparable cycles. In the car‐sharing configuration, only the handicapped mission cycles were simulated since this configuration was not designed to perform the other measured cycles. It is fundamental to stress out that WTW GHG emissions in the range of 40‐60 g/km are comparable to those promised by pure electric vehicles to reach production readiness in the near future.
Main Results
The figure shown was elaborated according to our own estimates, and the EUCAR study. Diesel CV refers to the GHG emissions of the vehicle currently performing mission 1 cycles, a good equilibrium between those of missions 2 and 3. The first 2 configurations presented next were equipped with a series hybrid powertrain which endows them both with decrease in energy use and GHG emission. The gasoline powered HEV‐
S configuration allows a 39% reduction and a similar diesel fuelled powertrains goes even further (47%). The remaining 3 options (all biofuels) provide GHG reductions granted by their biomass nature “credits”. Bioethanol has a higher GHG reduction potential than biodiesel and since both fuels emit the same amount of CO2 per mass in the Tank‐to‐Wheels phase because bioethanol is slightly less efficient it makes up for that difference in the Well‐to‐Tank phase, as biodiesel is penalized by higher fertilizer needs, which are significant N2O (GWP=310) emitters. Biogas has the lowest GHG emissions of all biofuels, but its low energy density reduces range severely in heavy vehicles performing in‐town cycles. The combined efforts of both technologies allow an 80% combined reduction in GHG emissions and a 40% energy consumption reduction due to powertrain hybridation. This performance is what many (e.g. Wuppertal Institute) see as a minimum threshold to allow CO2 concentration in the atmosphere to reach sustainable levels. As can be seen, even in “real life” driving cycles, the target put forward by the EU is not an impossible dream for a small freight diesel, as long as biofuels can be provided in significant amounts.
Cabin Configuration Homologation Cycles
NEDC Low EPA FTP
Ethanol Use (l/100km) 18.2 19.7Distance per cycle (km) 10.6 17.7Time (s) 1224 2500Cycles per day 33.0 19.8Total Daily Distance (Km) 349.8 349.6CO2 emissions (Kg/day) 96.1 103.9CO2 emissions (g/km) 274.6 297.3Bioethanol WTW CO2 (g/km) 103.0 111.5
Car‐Sharing Configuration Oeiras Driving Cycles
Mission 3
Ethanol Cons. (l/100km) 11.6Distance per cycle (km) 14.9Cycles per day 33.7Total Daily Distance (Km) 502.1CO2 emissions (Kg/day) 87.5CO2 emissions (g/km) 175.6Bioethanol WTW CO2 (g/km) 65.9
‐39% ‐47%
‐75%‐80% ‐82%
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M. Ramesohl, S. Merten, F. Fischedick; “Energy systems aspects of Natural Gas as an
alternative fuel in transport”, Wuppertal Institute for Climate Environment Energy,
Germany, 2003.
JRC, EUCAR and CONCAWE: “Well‐to‐Wheels analysis of future automotive fuels
and powertrains in the European context”, joint study elaborated under the plan Action
2113 and part of the Transport and Air Quality monitoring service by the Institute for
Environment and Sustainability (IES), Version 2c, Belgium, 2007.
P. Moriarty, D. Honnery: “Alternative transport fuels: the long‐term future”,
International Journal of Vehicle Design, Vol. 31, No. 1, 2003.
M. Schrock: “Biomass, Bioenergy & Biofuels”, presentation made on the Seminar
“Energy, Environmental Impacts and Sustainability”, Kansas University, USA, 2006.
D. Cohn, L. Bromberg, J. B. Heywood: “Calculations of Knock Suppression in Highly
Turbo charged Gasoline/Ethanol Engines using Direct Ethanol Injection”, article
produced for the Laboratory for energy and the environment, MIT 2006.
G. Knothe: “Cetane numbers of branched and straight‐chain fatty esters determined in
an ignition quality tester”, Fuel 82 (2003).
D. Cohn, L. Bromberg, J. Heywood: “Direct Injection Ethanol Boosted Gasoline
Engines: Biofuel Leveraging for Cost Effective Reduction of Oil Dependence and CO2
Emissions”, article for the Laboratory for energy and the environment, MIT 2005.
M. Brusstar, M. Bakenhaus: “Economical, High Efficiency Engine Technologies for
Alcohol Fuels”; paper for the International Symposia on Alcohol Fuels in San Diego,
September 2005.
K. Yamane, A. Ueta, Y. Shimamoto: “Influence of Physical and Chemical Properties of
Biodiesel Fuel on Injection, Combustion and Exhaust Emission Characteristics in a DI‐
CI Engine”, article 3‐08 presented at the 5th Symposium on Diagnostics and Modeling of
Combustion in Internal Combustion Engines, Nagoya, 2001.
M. Brusstar, M. Stuhldreher, D. Swain, W. Pidgeon: “High Efficiency and Low
Emissions from a Port‐Injected Engine with Neat Alcohol Fuels”, SAE, 2002‐01‐2743.
P. Aakko, N. Nylund: “Low Temperature Particulates From Alternative Fuels”,
presented at the Windsor Workshop Seminar on June 2004.
N. Jeuland, X. Montagne, X. Gautrot: “Potentiality of Ethanol as a fuel for Dedicated
Engine”, article signed on behalf of IFP, featured in the volume 59 of the magazine Oil &
Gas Science and Technology.
U. Baretzky: “The Development of the Audi 3.6‐litre V8 Twin Turbo FSI Engine for Le
Mans”, article produced on behalf of Audi AG, featured in the March 2002 edition of the
Magazine AutoTechnology.
M. Crawford: “Feasibility and Emissions of Compression Ignition Engines Fueled with
Waste Vegetable Oil”, Dissertation Thesis at University of South Florida, 2003.
Ahlbäck: “The evolution and functionality of the branch development project Biogas
Väst – an innovation system approach”; Msc. Dissertation Thesis at the University of
Chalmers, Götemborg 2003.
American Petroleum Institute: “Properties of Fuels ‐ table”; Publication No. 4261,