ethanol usage in urban public transportation...

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2010-36-0130I

Ethanol Usage in Urban Public Transportation - Presentation of Results

Sílvia Velázquez and Euler Hoffmann Melo Mackenzie Presbyterian University

José Roberto Moreira and Sandra Maria Apolinario and Suani Teixeira Coelho Brazilian Reference Center on Biomass-CENBIO/Electrotechnics and Energy Institute – São Paulo University

Copyright © 2010 SAE International

ABSTRACT

The usage of ethanol in buses is a reality in cities from Sweden, such as Stockholm. The technology of diesel bus adapted to operate with ethanol has been used in that country since 1985, with great success, mainly in the environmental point of view. With the intent of encouraging ethanol usage in urban public transportation aiming, among other goals, at the reduction of atmospheric pollution in the big urban centers, the BEST Project – BioEthanol for Sustainable Transport was created. Besides São Paulo (pioneer in the Americas), this project, encouraged by the European Union, counts with eight other cities located in Europe and Asia. In Brazil, the project was developed and coordinated by CENBIO – Brazilian Reference Center on Biomass, from the Electrotechnics and Energy Institute of USP. With the partnership of other institutions, the project is developed since 2007 and currently counts on two diesel buses adapted to operate with ethanol. The buses circulate in operatives from EMTU – São Paulo Metropolitan Company for Urban Transports, in the Jabaquara – São Mateus line, and in operative from SPTrans – São Paulo Transportations, in the Lapa – Vila Mariana corridor. This paper has as its purpose to present the BEST Project in Brazil, its partners and, mainly, the results from the demonstration tests performed in field, as well as the proposals of public policies that were elaborated and are being implemented. It is worth remembering that the technology of the buses pays attention to the EURO 5 strict emission Standards, a norm that was recently invigorated in Europe.

INTRODUCTION

The increase of the production of the automotive industry and the resultant increase of the consumer market are factors that have contributed to the inefficient occupation of the urban space, as well as to the increase of atmospheric air pollution in the metropolitan regions.

The transport situation in the São Paulo municipality is getting more and more critical, considering that the greatest fleet of Brazil, corresponding to 50% of the vehicles[1] existing in the State of São Paulo, is concentrated in it. The number of automobiles licenced daily in the city of São Paulo is high, approximately 800 vehicles, contributing to the increase of the fleet, which consists of 4,190,299 units[2].

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This excessive concentration causes sequential increases in the traffic jam rates and it has as its main consequence the deterioration of air quality in the urban center, jeopardizing the people’s health, a fact that becomes aggravated during the winter months, when the pollutants dispersion conditions are unfavorable.

Air pollution proceeding from automotive vehicles, fueled mainly by fossil fuels, generates damages to the health of the population that lives in the great urban centers. This way, some initatives have been taken to promote means of transportation that are more efficient, sustainable and using technologies with low emission of pollutants[3].

In the evolution of the Brazilian energy matrix, it can be observed that gasoline, composed by 25% of anhydrous ethanol (E25), is being gradually replaced by hydrated ethanol (E100), due to the technology of flex fuel vehicles, presenting a reduction, from 2007 to 2008, of approximately 2%[4]. However, there is the need of introducing technology to replace, at least partially, the diesel oil which represents over 50% of the fuel yearly consumed (Figure 1), besides being the worldwide fuel option for urban public transportation.

Óleo Diesel52,3%

Biodiesel1,2%

Gasolina A25,4%

Etanol Anidro5,9%

Etanol Hidratado

11,8%

GNV3,4%

Etanol Total

17,4%

Etanol Total

17,4%

Figure 1 – Vehicular Energy Matrix in Brazil in 2008[4]

With the goal to diversify the Brazilian energy matrix, there was the initiative of producing biodiesel (B100), which still cannot meet the demand in the short term, and it is known that gasoline and ethanol are not commonly used in urban public transportation. However, there is the possibility of ethanol utilization, in large scale, substituting diesel oil in urban public transportation, because ethanol already has infrastructure for production and distribution, therefore being able to replace diesel oil in a more significative way, in a shorter period time, besides being a renewable fuel with no sulfur content. It is worth noting that Petrobras has been investing billions of reais in researches to reduce the sulfur contents in diesel oil and in gasoline.

The substitution of diesel oil by ethanol used to stumble in problems of technical origin concerning the internal combustion engines, but the technological improvements provided, recently, an internal combustion engine fueled with additived ethanol whose applicability is the same as the one of a conventional diesel engine and is presented in this paper.

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SITUATION OF URBAN PUBLIC TRANSPORTATION AND ATMOSPHERIC POLLUTION IN THE CITY OF SÃO PAULO

Over the last 40 years, the increase of usage and possession of private automobiles at the São Paulo Metropolitan Region (SPMR) was possible due to the economic development of the country and to the inefficiency of the public transportation system in meeting the needs of the users with comfort and rapidity. Therefore, the use of private transportation is the preferential option of the population and it is very significative at the SPMR, fact that causes the aggravation of traffic conditions and of health due to the pollution generated by the vehicles in circulation, jeopardizing the life quality of the population [3].

The elaboration of policies that make the public transportation usage easier and more convenient to the user and that introduce vehicles with technology of low pollutant emissions, alongside urban planning measures, can significatively improve the life quality of the population that reside at the SPMR.

The air quality monitoring in the State of São Paulo is performed by the Environmental Agency of the State of São Paulo (CETESB) which registered, in the year of 2007, that the total fleet of vehicles of the SPMR originated the emission (Figure 2) of 1.5 million tons of carbon monoxide (CO), 365 thousand tons of hydrocarbons (HC), 339 thousand tons of nitrogen oxides (NOx), 29.5 thousand tons of particulate materials (PM) and 8.2 tons of sulfur oxides (SOx).

The automotive vehicles (light and heavy) were solely responsible for 97.5% of the CO emissions, 96.7% of the HC emissions, 96% of NOx, 32% of SOx and 40% of the PM emissions. Regarding heavy vehicles, fueled in almost their entirety with diesel oil, one can observe a significant participation of the PM emissions and, mainly, of the NOx ones, representing 28.5% and 78.5% of the emissions, respectively. The participation of the automobiles powered by diesel oil was also significative to the other mentioned emissions, being 25% of CO, 15.8% of HC and 15.1% of the emissions of SOx[1].

72,5%81,0%

17,6% 17,1%11,5%

25,0%15,8%

78,5%

15,1% 28,5%

67,9%

10,0%

25,0%

25,0%

4,0%3,2%2,5%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

CO HC NO SO MP

Aero. SecundáriosRessuspensãoProc. IndustrialVeículos PesadosVeículos Leves

Figure 2 – Relative emissions of pollutant substances per kind of source - 2007[1]

Although it is not specified in Figure 2, the ozone (O3) must be mentioned. It is classified as a secondary pollutant, because its generation proceeds from the photochemical reaction between hydrocarbons and nitrogen oxides, specifically NO2, and not from an active source of ozone. Nitrogen oxides, alongside hydrocarbons,

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generate the photochemical smog, whose main products are photochemical oxidants, among them, the ozone[1]. Therefore, any measure of reduction of nitrogen oxides and hydrocarbons is an indirect control of ozone formation.

Pollution can cause respiratory and cardiovascular diseases, such as pulmonary and subclinical systemic inflammation, increase of blood pressure, greater risk of arrhythmias and myocardial infarction, besides the reduction of approximately 1.5 years of life expectancy of an urban center inhabitant. According to studies accomplished by the Medicine College of USP, in the city of São Paulo alone the deaths proceeding from air pollution are of approximately 3500 persons per year. If the potentially productive years of the prematurely lost lives are accounted, adding the public expenses with treatments of cronical diseases related to air pollution and to the diminution of work capability of each individual[6], like in São Paulo, the costs related to the pollution reach US$ 400 millions per year (conservative estimation) [5].

In this context, the Project BEST – BioEthanol for Sustainable Transport – is then presented, a project that presents the possibility of reducing the pollutant emissions in urban centers by means of the encouragement to sustainable urban public transportation use, with the use of technology of internal combustion engine that presents smaller emissions. Before introducing the project, the involved fuels and the technology used are presented.

INVOLVED FUELS

In this item, the two fuels involved in the development of Project BEST are listed: additived ethanol and diesel oil, used in bus powered exclusively by diesel, which circulated in parallel, as a “shadow”, to the bus that is object of this work, powered by additived ethanol.

Diesel oil is a derivative product from raw petroleum, composed of hydrocarbons, which can have an undesirable quantity of sulfur, which besides being harmful to the functioning of the engine, is also an atmospheric pollutant[7].

The self-ignition quality of diesel oil is measured according to the cetane number (CN), which measures the tendency of a fuel to self-inflame in a certain temperature, compared to a standard fuel, which is composed only of cetanes and to which the CN 100 is attributed. A fuel with low CN causes an inefficient functioning of the Diesel cycle engine, while a fuel whose CN is close to 100 is ideal for a good functioning of a Diesel cycle engine[8].

Another index that measures the diesel quality is the sulfur index present in the fuel. In Brazil, two kinds of diesel oil are sold, according to the quality standard stipulated in the technical ordinance ANP N. 6/2001[9]; they are the Metropolitan Diesel (diesel oil type D) and the Countryside Diesel (diesel oil type B).

The metropolitan diesel oil is commercialized in the metropolitan regions of São Paulo, Campinas, Belo Horizonte, Fortaleza, Belém, Rio de Janeiro, Recife, Aracaju[10] and the sulfur index present in its composition is of around 500 ppm. The countryside diesel oil, in its turn, is commercialized in the other areas of the national territory and the sulfur index of its composition is of 1800 ppm. Metropolitan diesel oil is naturally more expensive than countryside diesel oil due to the desulfurization process that it suffers before being commercialized[7].

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Hydrated ethanol is an alcohol that has two atoms of carbon and one hydroxyl radical in its composition, besides a low CN, what prevents it from being used in Diesel cycle engines without being initially additived with an ignitor additive that increases its CN. In the additived form, ethanol begins to have self-ignition properties by compression and, therefore, it can be used as fuel in Diesel cycle engines.

Some well-known and researched ignitor additives, including in Brazil, are usually composed of nitrates, peroxides and nitrites. However, the nitrates compounds are hard to be manipulated, because they exhale harmful steams to human health, with vasodilator effect. The new-generation additives are no longer nitrates compounds, presenting easier and less harmful handling than the past ones. However, even so, several security measures are necessary in the handling, because it is a solution composed of polyethylene glycol (PEG) and ethanol, highly inflammable[11].

PEG is a polymer synthesized from the polymerization reaction of ethylene glycol. Despite the smaller efficiency as CN improver when compared to the nitrogen compounds, such as the triethylene glycol dinitrate, PEG is easier and safer to be handled than the compounds that have nitrogen in their formulas, because it does not release harmful steams to human health. Another advantage of using PEG is its lubrication property of the fuel injection system, what reduces the quantity of lubricants added to the fuel[12].

The fuel used in the Diesel cycle engines powered by additived ethanol is composed, in its majority, of hydrated ethanol with maximum acceptable water volume index of 5%[13] and it received the generic name of ED95, in allusion to the percentage mass of ignitor in the fuel. In Sweden, the only ED95 manufacturer for Diesel cycle engines is the SEKAB company, whose sold product is named Etamax D[14], which is also known as Beraid. It was supplied by the manufacturer, diluted in 50% of ethanol, to be subsequently blended with the final ethanol quantity.

The decision of not to import the already additived ethanol as ED95 had as its purpose to avoid that the ethanol, a product easily found in national territory, was imported from Sweden; actually, the ethanol used in Sweden is produced in Brazil. However, due to security reasons, the Beraid can only be transported when already diluted in ethanol[14].

TECHNOLOGY OF DIESEL CYCLE ENGINE FUELED WITH ADDITIVED ETHANOL

The technology of Diesel cycle engines powered by additived ethanol has been being perfected by Swedish Scania since the decade of 1980. Nowadays, these engines present high degree of technological development and of reliability, besides reduced pollutants emissions. In the European Union, the engines produced from October 2009 on are certified as Euro 5, which is a regulation that hás very strict standards for pollutants emission[15].

The Diesel cycle engine powered by additived ethanol is in its third generation and already has Euro 5 emission standard, without any kind of post-treatment of the exhaust gases, besides also being certified, in the Stockholm municipality[13], as Environmentally Enhanced Vehicle (EEV), rule that still has no date to enter into force in Europe and is stricter than the Euro 5 standard. The engine is available in the market and it is widely used in Sweden, where around 600 buses circulate in different cities in the country, powered by additived ethanol.

According to the manufacturer, the adaptation of the Diesel cycle engine to the usage of additived ethanol did not require significative changes. The main difference between the Diesel cycle engine and the one powered by

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additived ethanol is in the piston, which accommodates the volume that is not shifted inside the cylinder, the “dead volume”, located in the upper part of the piston[16]. Figure 3 presents the pistons of the DC9 E02 Scania engine, powered by ethanol, and the ones of the DC9 17 Scania engine, powered by diesel oil, of equivalent potency, that reach 270 hp in close rotations, but with differentiated compression rates, being 28:1 for the additived-ethanol engine and 17:1 for the diesel engine.

Figure 3 – Pistons of Diesel cycle engines of same potency[17]

The piston of the Diesel cycle engine powered by additived ethanol was geometrically projected to accomodate the “dead volume” smaller than the one of the conventional diesel engine and thus reach the high compression rate.

In the Diesel cycle engine powered by additived ethanol, whose compression rate is of 28:1, the air is compressed 28 times in order to reach the self-ignition temperature of the additived ethanol, which is equal to 360 ºC[11]. The high compression rate of the Diesel cycle engine powered by additived ethanol is justified as a compensation of the low cetane number (CN) of the fuel, Etamax D, which is equal to 10, compared to the one of mineral diesel oil, which is of approximately 50[14].

From the thermodynamic point of view, the compression rate is responsible for the motor thermal yield, what means that the energy utilization of the fuel will be as big as the compression rate involved in the thermodynamic cycle[18].

Other differences are the greater volumetric capability of the nozzles and the use of materials resistant to ethanol, due to corrosion[13].

The fuel used in Diesel cycle engines must have property of self-ignition by compression, which is the principle of functioning of a Diesel cycle engine; however, ethanol does not have such property. In order for the ethanol to suffer self-ignition, besides the high compression rate employed in these engines, an additive is blended with the ethanol[14].

Ethanol has smaller energy content per unit of volume when compared to diesel oil, so a greater volumetric capability of the injectors is necessary, what also justifies the higher fuel consumption per kilometer, in the order of 60% bigger than the volume of diesel oil consumed by an equivalent engine to travel the same distance[15].

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The only manufacturer of Diesel cycle engines powered by additived ethanol is the Swedish Scania, which produces these engines regularly from the year of 1989 on, when the ethanol buses were officially incorporated to the urban buses fleet in Stockholm[15]. Nowadays, the only model of additived-ethanol engine commercially available (Figure 4) is the DC9 E02 270 model[19].

Figure 4 - DC9 E02 Scania Engine[19]

The engines have few differences in their mechanical configuration, thus not needing great modifications in the layout from the factory for its serial production.

The torque and potency curves of the Diesel cycle engine powered by additived ethanol are very similar to the torque and potency curves of an equivalent engine powered by diesel oil, what grants good driveability of the bus powered by additived ethanol, because the engine develops high torque in low rotations, as occurs in a conventional diesel-powered vehicle. The torque and potency curves in function of the rotation are also very similar between the Diesel cycle engines powered by additived ethanol and the ones powered by diesel oil. Such fact grants to the ethanol-powered engine the same applicability of the conventional diesel-powered engines[3].

TECHNOLOGIES THAT REDUCE THE POLLUTANTS EMISSION

The emission of pollutants of internal combustion engines can be reduced with the use of systems for post-treatment of exhaust gases and with the use of engine management systems. In Brazil, as the Program for Control of Air Pollution from Mobile Sources (PROCONVE) becomes more and more demanding regarding the emissions limits, the use of systems for post-treatment of exhaust gases, associated to the management systems, becomes imperative to adequate the internal combustion engines to the limits imposed by PROCONVE[3].

The system of gases recirculation, known as Exhaust Gas Recirculation (EGR), and the electronic injection system, which allows several stages of fuel injection with the goal of raising the performance of the engine and reducing the emissions, are examples of management systems of diesel engines.

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There are systems for post-treatment of gases that neutralize or prevent that pollutants are discharged in the atmosphere, using urea to neutralize the NOx, and filters for particulate materials and they can be used together so that the engine is framed in the predetermined emission limits[20].

The ethanol fuel is considered a low-pollutant fuel, however, the high compression rate involved in the Diesel cycle engine powered by additived ethanol, which is of 28:1, has as its consequence high pressures and high combustion temperatures in the interior of the cylinders, thus favoring the formation of NOx[20] in unacceptable quantity, in case a management system is not used to reduce the emission of NOx to the emission level accepted by the Euro 5 standard, the EGR, whose configuration is presented in Figure 5.

Figure 5 - Configuration of the EGR system[21]

The concept of the gases recirculation system is based in the utilization of a parcel of the exhaust gases directed to the admission of the engine, that is, from 20% to 30% of the inert exhaust gases are admitted again in the combustion cylinders. It is verified that the recirculation of exhaust gases propitiates the reduction of formation of NOx. From the thermodynamic point of view, the engine suffers a reduction of its thermal yield, however, the reduction of the specific NOx emission due to the EGR system utilization is in the order of 25% to 40%. The use of EGR requires special cares in the project of the engine, because there would be a tendency of increase of fuel consumption due to the yield loss. So, for this control, EGR is minimized in regimes of high potency and torque[20].

The use of fuels with low sulfur content is also another necessary caution, because the sulfur, when burned, produces sulfur oxides (SOx), proceeding from the sulfur contained in the diesel oil that, in reaction with water, produces sulfuric acid (H2SO4), potentiating the deterioration of the equipment and of the engine, since the sulfuric acid, besides corrosive, has also contaminant effect in the lubricant oil[20]. The adequate diesel oil for use of EGR is the one whose sulfur content is smaller than 500 ppm, what implies in an advantage of the additived ethanol, because it does not have sulfur in its composition.

The engine powered by additived ethanol uses a new-generation EGR system, the Double-stage EGR, which was projected throughout Five years of research at the Scania Technical Center in Södertälje, in Sweden, with

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the purpose of ensuring the control of flow and temperature of recirculated gases to engines of great potency[22] and it is presented in Figure 6.

Figure 6 – Double-stage EGR system[22]

In the Double-stage EGR system, a parcel of the exhaust gases is recirculated, cooled and finally directed to the admission collector or returns to the cooling stage. The flow of the parcel of exhaust gases that is directed to the admission is electronically regulated by the EGR valve and by the variation of the geometry of the turbocharger, according to the engine’s potency necessities. The first stage consists in the cooling by means of water from the exhaust gases throughout the block of the engine, while the second stage consists in the cooling by means of an air-air radiator assembled over the cooler of the intake air [22].

THE PROJECT BEST - BIOETHANOL FOR SUSTAINABLE TRANSPORT AT THE SPMR

The Project BEST – BioEthanol for Sustainable Transport was an initiative of the European Union, coordinated by the Stockholm City Hall, in Sweden. Its purpose was to encourage the use of ethanol, in substitution for diesel oil, in urban public transportation in Brazil and worldwide. The vehicles used in the tests were monitored and evaluated to demonstrate the energy and, mainly, environmental efficiency of ethanol.

After the results, Project BEST and the European Union provided recommendations for the formulation of public policies of incentive to the use of the technology. CENBIO – the Brazilian Reference Center on Biomass, part of IEE – Electrotechnics and Energy Institute, of USP – São Paulo University, creator and coordinator of the Project in Brazil, developed two goals. Besides São Paulo, pioneer in the Americas, eight other sites of Europe and Ásia took part of the project: Stockholm (Sweden), Madrid and Basque Country (Spain), Rotterdam (Netherlands), La Spezia (Italy), Somerset (England), Nanyang (China) and Dublin (Ireland)[15].

One of the Brazilian goals of Project BEST was to evaluate the ethanol use as a fuel alternative to diesel oil, in buses used for public transportation, by means of comparative following of the operational performance of experimental fleet, taking as reference an equivalent diesel bus. The technology used, diesel engine adapted to

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operate with ethanol, developed by the Swedish Scania company, is available and technically perfected. Around 600 buses powered by Brazilian ethanol circulate in Sweden, approximately 380 of them being in Stockholm[23].

Since 2006, CENBIO searched for partners to develop Project BEST in Brazil and, finally, in 2007, nine partnerships were materialized. Scania Latin America imported the bus frame and the engine from Sweden; Marcopolo projected, built and provided the bus body; the Sugar Cane Industry Union (UNICA) supplied the ethanol for the tests; BAFF/SEKAB supplied the additive, of its own fabrication, to be blended with the ethanol; while Petrobras imported the additive. The blending of the additive with the ethanol and the distribution of the fuel in the bus operator companies was under responsibility of BR Distributor. For the initial tests of assembly of the bus body, Copersucar imported the first allotment of the additived ethanol (Etamax)[15].

The bus frame and Scania engine embarked, in Sweden, in April and arrived to Brazil in May 2007, at the port of Santos (Figure 7).

Figure 7 – Bus frame and engine at the port of Santos[15]

The bus frame and engine were sent to the Marcopolo’s factory, in Caxias do Sul in the State of Rio Grande do Sul, in order for the bus body to be manufactured (Figure 8) (CENBIO, 2007).

Figure 8 – Manufacture of the bus body at the Marcopolo’s factory[15]

The bus frame is a Scania standard one that meets the European standard and, for this reason, the construction of the bus body was atypical for the Marcopolo engineers. An example of adaptation was the accomodation of the fuel tanks in the vehicle, as shown in Figure 9. The capacity of the fuel tanks of the ethanol vehicle must be

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bigger to guarantee the same autonomy of a diesel-powered vehicle and such fact is justified by the greater consumption of additived ethanol in comparison to diesel oil, due to the lower calorific power of ethanol. The capacity of the bus powered by additived ethanol is of 400 liters, divided in three tanks, while the capacity of a diesel bus is of 300 liters of fuel[24].

Figure 9 – Internal space occupied by the fuel tanks[3]

The manufacture of the bus body was concluded and the painting was stylized, as shown in Figure 10.

Figure 10 – The bus powered by additived ethanol[24]

The launching of the project took place on October 23rd, 2007, at USP, with the presentation of the bus in ceremony that counted with the presence of 300 persons, including personalities as Gilberto Kassab (Figure 11), Mayor of the City of São Paulo who, in this same occasion expressed support to Project BEST and emphasized the utilization of cleaner transport technologies as the main means of reduction of air pollution in the São Paulo Metropolitan Region, besides Alexandre de Moraes, who then was Secretary of Transports of the Municipality of São Paulo[24].

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Figure 11 - Mayor Gilberto Kassab and Professor José Roberto Moreira, idealizer of BEST[24]

The tests were initially realized at the METRA operator – Metropolitan Transport System of São Paulo, of the concessionaire EMTU/SP – Metropolitan Urban Transport Company S.A., in the Jabaquara - São Mateus corridor, which is 33 km long and transports 6 million passengers per month and, afterwards, in operator company indicated by SPTrans – São Paulo Transport S.A., which is also a partner in the project[15].

To evaluate the technology developed for utilization of ethanol in buses for urban public transportation, the functioning of the bus with engine powered by ethanol was followed and documented, circulating in a specific line, comparatively to a similar bus, powered exclusively by diesel oil. Such data refer to the consumption of fuel, traveled kilometers, performance, occurrences of accidents or mechanical problems, from the Mean Kilometers Between Failures (MKBF) and others.

For comparative effect, the same following was adopted for all the evaluated buses and emission tests were not realized, because the engine in operation was already homologated.

The new-generation engine, brought to Brazil by Scania, was incorporated to Project BEST and officially launched in ceremony (Figure 12) held on November 12th, 2009, at the Viação Gato Preto, which incorporated the vehicle to its fleet and realizes in it the demonstration tests, in the Lapa – Vila Mariana bus line[25].

The event once again counted with the support of the Mayor of the city (Figure 13) who, at the occasion, related the promulgation of the Law 14.933, also known as Climate Change Law of the City of São Paulo, from June 5th, 2009, with the importance of the bus powered by ethanol to meet it. Such law has as its goal the reduction of greenhouse effect gases in 30% by the year of 2012, by means of utilization of cleaner technologies from renewable fuels[26]. The bus powered by additived ethanol shows itself as a viable alternative to the fulfillment of the reduction goal for emission of greenhouse effect gases.

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Figure 12 – 2nd bus powered by ethanol[26]

Figure 13 – Mayor Gilberto Kassab and the Secretaries for Transport and for Green and the Environment[26]

The new engine is advanced even to the European emission Standards, because it meets the EURO 5 specifications, which came into force in Europe in 2009, and also the Enhanced Environmentally Friendly Vehicles (EEV), rule that still does not have a date to enter into force in the European Union. It is homologated in Brazil by CETESB and is perfectly applicable to the Brazilian reality, because its emissions are well below the limits imposed by PROCONVE.

The results of the rehearsal of the engine, compared to the limits established in PROCONVE, show that the emission values of the diesel cycle engine powered by additived ethanol are much lower than the limits imposed by the P-5 and P-6 stages of PROCONVE. The P-6 stage is the strictest Brazilian emissions limit for fabrication of internal combustion engines and entered into force in 2009.

Table 1 presents the emissions of the Diesel cycle engine powered by additived ethanol and makes a comparison of the results with the stages of PROCONVE.

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Table 1: Emissions of the diesel cycle engine powered by additived ethanol[27].

EMISSION VALUES CO (g/kWh) HC (g/kWh) NOx (g/kWh) PM (g/kWh)

Rehearsal in the engine (1)

0. 00 0.05 1.7 0.01

PROCONVE P-5 (2) 2.1 0.66 5.0 0.10

PROCONVE P-6 (3) 1.5 0.46 3.5 0.02

(1) Rehearsal realized on 09/13/2007, at the RDW laboratory, in Netherlands

(2) Established in the Conama Resolution n. 315/02, in force since 01/01/2006.

(3) Conama Resolution n. 315/02, Art.15, Table 1, line 2, in force since 01/01/2009.

With such levels of strictness, the reduction of over 80% of the emissions of gases responsible for global warming is estimated, as well as a reduction of 90% of particulate matter and 62% of NOx released in the atmosphere, besides the absence of sulfur (S) emission, which composes the SOx, responsible for acid rain.

The reduction of the emissions of local pollutants (MP, NOx and CO) reduces the occurrence of cardio-respiratory dieseases, a fact that must be taken into consideration, mainly, in the metropolitan regions where the population is numerous, there is great concentration of vehicles and atmospheric pollution sources, besides the unfavorable pollutants dispersion conditions. The great advantage of ethanol utilization as fuel in urban public transportation is the environmental gain with the reduction of emissions.

ADAPTATIONS OF TECHNIQUES PERFORMED IN THE ETHANOL BUS

In operation in the EMTU corridors, the vehicle started presenting sudden halts of the engine in slow running. Such problem manifested itself more frequently in hot days, when the ambient temperature reached 26 °C or over and in the end of long slopes of the route.

In a more detailed analysis, abnormal conditions of temperature and pressure were found in the fuel line, being: 58 °C the temperature in the fuel line of engine Power and the pressure of the same that was well below the normal conditions, noticing that when it reached the value of 0.5 bar that caused the engine to halt. The normal pressure of the fuel pump should be of approximately 3 bar, which might present small variations.

The original project of the power system, which was developed in Sweden, foresaw the preheating of the fuel before it arrived to the engine and, this way, the vehicle would Begin to present better energy efficiency. In order for the fuel to be preheated, a microchamber of preheating was installed in the outlet of the fuel tank (Figures 14 and 15). The device reused the thermal energy from the return fuel line from the engine to the tank.

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Figure 13 – Arrangement of the fuel tanks and of the fuel preheater[28]

Figure 14: Fuel preheater[28]

There was an excessive heating of the Power line, and a deviation of the return line of the engine straight to the tank was arranged (Figures 15 and 16). From then on, there would be no more heat transference between the return line and the power line of the engine fuel.

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Figure 15 – Preheater with the unused return lines[28]

Figure 16 – Overview of the tank in which the deviation of the fuel line was installed[28]

After the modifications, new data were collected: 28 °C of temperature and 2.71 bar of pressure in the engine’s fuel power line. These are normal conditions of operation.

The initial project, developed in Europe, foresaw the functioning of the vehicle in temperate climate (Figure 17), where the average ambient temperature is lower than the one for tropical climate. In hotter days, the temperature of the fuel line reached up to 58 °C, a temperature that could increase even more when the engine would be slow running. The excessive heating was causing the vaporization of the fuel in the power line of the engine. The solution found was to deviate the fuel return from the engine straight to the tank. The maintenance performed consisted in an adaptation of the project to the Brazilian conditions (tropicalization).

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Figure 17 – Vehicle powered by additived ethanol in the city of Arjelog, Sweden[29]

SUMMARY/CONCLUSIONS

The manufacturers of light and heavy automotive vehicles, in Brazil and worldwide, face the pollutants emission limits established by specific legislations and, because of this, they are searching for technological solutions to meet these limits.

The results obtained in the rehearsals of pollutants emission of the diesel engine powered by ethanol are very favorable to the implementation of such technology, according to comparison realized between the emission limits stipulated by PROCONVE P-5, P-6 and the tests results of the engine obtained in laboratory. Therefore, the emission of pollutants in the additived-ethanol engine is a very favorable justification to the implantation of this technology in urban public transport.

However, even with the potential gains in public health and in life quality of the population of the metropolitan regions, the technology of Diesel engines powered by additived ethanol faces barriers, because it directly competes with the technology of conventional Diesel engines that have a lesser cost, besides having to face the insecurity of the transportation sector in acquiring a new technology never before used in large scale in Brazil, as well as the production of the engines and of the additive in Brazil[30].

Until the technology acquires scale economy and the reliability of the bus concessionary companies, the production of engines, as well as of the additive in Brazil, would dependo n fiscal incentives promoted by the government in order to make them competitive against the conventional Diesel technology[30].

When considering that pollution causes a reduction of approximately 1.5 year in life expectancy of an urban center inhabitant, that the governmental expenses with health problems related to pollution are big and that the results of the emission tests meet and overcome the limits established by the aforementioned rules, one can conclude that it is a solution for public health and for a possible relocation of these avoided expenses in education and health, for instance, and this solution is available in short term.

Facing the already existent infrastructure for distribution and production of ethanol in Brazil, specially in the State of São Paulo, the introduction of Diesel cycle engines powered by additived ethanol in urban public transportation is possible, being an already available alternative to diminish the emissions of greenhouse effect gases and, mainly, to reduce air pollution in the metropolitan regions.

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The technology presents itself technically developed and perfected, since there are 600 additived-ethanol buses in circulation in Sweden, therefore, the tests named as “demonstration tests” were accomplished in order to attract interest of the public power.

Regarding the public sector, the tax incentives would be perfectly justifiable, because there would be a diminution of other public expenses with treatment of cardio-respiratory diseases that are aggravated with the exposition to air pollution. The estimated cost, in SPMR alone, with treatments of cardiovascular diseases aggravated by the pollution, due to the reduction of the work capacity of the inhabitants and 3500 deaths per year, reach approximately U$350 millions, which could be saved in the health sector, with the improvement of air quality and, then, used as incentive, for instance, in the transportation sector, making the acquirement of the buses powered by additived ethanol easier.

More than stimulating ethanol usage in public transportation, the initiative launched by CENBIO, partner enterprises and European Union advances in the discussion on the economic model of development for which Brazil currently searches. This moment shows itself as very favorable to the implantation of the technology in Brazil, which is the greatest sugarcane ethanol producer. The availability and the perspectives for ethanol production added to the environmental competitive advantages, such as the reduction of the emissions of pollutant gases, suggest that the use of ethanol in diesel engines offers a series of benefits and favorable points to the model for Brazil. Among them, there is the diversification of the energy matrix in the transportation sector, the use of a national fuel, besides the use of distribution infrastructure compatible with the one that exists in Brazil.

The results allowed to identify the technical-economic barriers that interpose themselves to the viabilization of implantation of this technology in public transportation in Brazil and the formulation of public policies of incentive to its utilization, which involve the municipal, state and federal governmental levels, and such incentives are perfectly justifiable, because there would be a reduction of public expenses with treatments of diseases that are aggravated with the exposition to air pollution and that can reduce the work capacity of the population, as well as its life expectancy [30].

REFERENCES

1. CETESB – Environmental Agency of the State of São Paulo. Padrões e Índices. Available in: http://www.cetesb.sp.gov.br/Ar/ar_indice_padroes.asp. Access in: 04/11/2008.

2. DENATRAN – Brazilian National Traffic Department. Frota de Veículos por tipo, segundo os Municípios da Federação. Available in: http://www2.cidades.gov.br/renaest/listaArquivoPrincipal.do?op=1&doDownload=true&arquivo.codigo=176. Access in: 09/29/2008.

3. HOFFMANN MELO, Euler. Ônibus movido a etanol – Um estudo de caso. Engineering School of the Mackenzie Presbyterian University scola de Engenharia da Universidade Presbiteriana Mackenzie (Course Final Paper). São Paulo, 2009.

4. ANP – Brazilian National Petroleum Agency. Óleo diesel: preços e custos. Lecture ministered at the Chamber of Deputies in public hearing: Special Commission – PL 1.927/03 and apensados. Brasília – DF. Available in: www.anp.gov.br Access in: 08/31/2009.

5. SALDIVA, Paulo H. N. Palestra proferida durante a 7ª Conferência de Produção Mais Limpa. São Paulo, 2008.

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6. SALDIVA, Paulo H. N. Transporte Sustentabilidade e Cidadania. Boletim DNA Brasil. São Paulo, 2008. Available in: http:// www.dnabrasil.org.br Access in: 03/04/2008.

7. SILVA, E. José. Equilíbrio líquido-líquido em mistura hidrocarbonetos+álcoois: comportamento de fases e desenvolvimento de aditivos para aumentar a miscibilidade de misturas óleo diesel+etanol. (Doctoral thesis for the State University of Campinas - UNICAMP). Campinas, 2005. Available in: http://www.biq.iqm.unicamp.br. Access in: 08/31/2009.

8. RACHE, Marco. Mecânica Diesel. 1st issue, Hemus Publisher. São Paulo, 2004. 9. ANP – Brazilian National Petroleum Agency. Regulamento Técnico ANP N° 6/2001. Rio de Janeiro,

2001. 10. ANP – Brazilian National Petroleum Agency. Portaria N°310, de 27 de dezembro de 2001. Rio de

Janeiro, 2001. 11. GREENENERGY. Website specialized in renewable energies. E95 Material Safety Data Sheet.

Commission Decision 2000/352/EC. London, 2000. Available in: http://www.greenenergy.com/products/MSDS/E95.pdf. Access in: 09/05/2008.

12. NIGRO, F. E. Baccaro. Professor of the Polytechnical School of the University of São Paulo. Information obtained by means of personal communication on 09/17/2008. Venue: Millenium Events Space, XVI International Symposium of Automotive Engineering – SIMEA 2008. São Paulo, 2008.

13. BEST - Bioethanol for Sustainable Transport. The Bioethanol bus. Sweden, Stockholm, 2006. Available in: http://www.best-europe.org. Access in: 03/18/2008.

14. SEKAB. Etamax D Fuel Composition. Sweden, Stockholm, 2001a. Available in: http://www.sekab.com. Access in: 03/17/2008.

15. CENBIO – Brazilian Reference Center on Biomass. Primeiro relatório de atividades do Projeto BEST. São Paulo, 2007.

16. ALMEIDA, S. C. A. Máquinas Térmicas - [s.n]. Federal University of Rio de Janeiro (UFRJ), 2006. Available in: http://www.mecanica.ufrj.br. Access in: 10/10/2008.

17. SCANIA. Engine Diagrams. Available in: http://www.scania.co.uk. Access in: 04/10/2008. 18. MORAN, M. J.; SHAPIRO, H. N. Princípios da Termodinâmica para Engenharia. 4th issue, LTC

Publisher, Rio de Janeiro, 2002. 19. SCANIA. Bodybuilding Information. Available in: http://www.scania.com. Access in: 09/10/2007. 20. BRANCO, Gabriel Murgel. Redução das emissões do transporte público através de melhores

tecnologias e combustíveis. Biannual conference and exhibit of the clean air initiative for Latin American Cities. São Paulo, 2006.

21. AUTOSPEED. Website specialized in autoparts and vehicles. Why and how gas recirculation is again big news. Victoria – Australia, 2008. Available in: http:// autospeed.com. Access in: 10/10/2008.

22. SAE BRASIL. Solução Euro V da Scania deixa o pós Tratamento para trás. Revista Engenharia Automotiva e Aeroespacial: year 7, issue 32. São Paulo, 2008.

23. SCANIA, Latin America. Ônibus Scania movido a etanol é apresentado em São Paulo. 2007. Available in: http://www.scania.com.br. Access in: 03/18/2008.

24. CENBIO – Brazilian Reference Center on Biomass. Segundo relatório de atividades do Projeto BEST. São Paulo, 2008.

25. CENBIO - Brazilian Reference Center on Biomass. Terceiro relatório de atividades do Projeto BEST. São Paulo, 2009.

26. PMSP – São Paulo Municipality City Hall. São Paulo tem lei de mudanças climáticas. São Paulo, 2009. Available in: http://portal.prefeitura.sp.gov.br Access in: 15/09/2009.

27. SCANIA, Latin America. Homologação Técnica do Motor - CETESB. São Bernardo do Campo, January 14th, 2008.

28. SCANIA. Relatório de Reunião entre técnicos da Scania do Brasil e CENBIO. Held in Scania Latin America, São Bernardo do Campo – SP Access in: 02/22/2008.

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29. SCANIA. Banco de imagens. Available in: http://imagebank.scania.com. Access in: 08/31/2009. 30. CENBIO - Brazilian Reference Center on Biomass. BEST Report on Guidelines, Requirements and

Barriers. São Paulo, 2009.

CONTACT INFORMATION

Sílvia Velázquez and Euler Hoffmann Melo

Presbyterian University Mackenzie

Rua da Consolação, 930 - Consolação - São Paulo - SP – Brazil

Zip code 01302-907

Telephone: +55 11 2114 8552 Fax: +55 11 2114 8553

Mobil: 55 11 9243-2555 - [email protected]

José Roberto Moreira and Sandra Maria Apolinario and Suani Teixeira Coelho

Brazilian Reference Center on Biomass-CENBIO/Electrotechnics and Energy Institute – São Paulo University

Av. Prof. Luciano Gualberto, 1289 – Cidade Universitária – São Paulo – SP - Brazil

Zip code 05508-010

Telephone: 55 11 3091-2650 Fax: 55 11 3091-2653 - [email protected]

ACKNOWLEDGMENTS

Many thanks to the partners of the project for the boldness of believing in the idea and for giving all the needed support so that the two buses can keep circulating and a fleet can be implemented in the city of São Paulo.

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