Comparative Analysis of Gas Emissions from a Vehicle Running on Ethanol and Natural Gas Fuel

Transcription

1 Journal of Mechanics Engineering and Automation 4 (2014) D DAVID PUBLISHING Comparative Analysis of Gas Emissions from a Vehicle Running on Ethanol and Natural Gas Fuel Raphael Araújo de Holanda, Gil Colona Laranja, Cleiton Rubens Formiga Barbosa, Francisco de Assis Oliveira Fontes and Cleiton Rubens Formiga Barbosa Junior Department of Mechanical Engineering, Federal University of Rio Grande do Norte, Natal/RN , Brazil Received: March 21, 2014 / Accepted: April 08, 2014 / Published: July 25, Abstract: It is known that transport sector has a fundamental importance in modern society, as economic development is directly linked to mobility. Over years, transport became linked to different environmental problems, which can be detached greenhouse gases emissions in atmosphere, where in recent decades can be perceived intensification and targeting of efforts in research and development of new technologies to reduce levels of greenhouse gases emissions in atmosphere. In this context, it can be highlighted modern systems of electronic engine management, new automotive catalysts and use of renewable fuels which contribute to reducing environmental impact. This research had, as its purpose, analysis of fuels characteristics used for testing, comparative analysis of gas emissions from a motor vehicle running on ethanol or natural gas fuels according to NBR 6601 and conducting tests to estimate maximum catalytic efficiency. For implementation of trial, a flex vehicle was installed in a chassis dynamometer equipped with a gas analyzer, in order that before completion of urban driving cycle, were determined content of hydrocarbons corrected, carbon monoxide corrected, carbon dioxide and oxygen present in gas emissions from engine. The research concluded that: performance analysis for characterization of fuel showed consistent with ANP specifications; after tests performances, it can be stated that natural gas fuel was fuel which had highest content of hydrocarbons and carbon monoxide corrected, while ethanol had highest amount of carbon dioxide and oxygen residue present in gas emissions; before a comparative analysis, vehicle catalyst showed best performance for reducing content of hydrocarbon corrected present in exhaustion gases when it worked with natural gas fuel and showed maximum efficiency of 100% to reduce content of carbon monoxide corrected for both fuels. Before this, it can be stated that vehicle catalyst showed satisfactory performance, achieving good reduction levels of greenhouse gases emissions. Key words: Gas emissions, ethanol, natural gas fuel, NBR 6601, catalytic efficiency. 1. Introduction It is well known that a long time ago, transport sector has a fundamental importance in global society, as economic development is directly related to mobility of people and merchandises, and vehicles means of locomotion most used until today. Over time, re was an increase of number of vehicles circulating daily in world and refore, growth in greenhouse emissions released into atmosphere, as result of combustion process Corresponding author: Raphael Araújo de Holanda, master, research fields: environmental emissions, renewable energy, rmal engineering and rmodynamics. raphaelholanda@hotmail.com. inside motor vehicle [1]. At same time of this scenario, it is observed, in recent decades, search for improvements to answer se requirements, leading intensification of efforts in research and development of new technologies, which will promote reduction of emission levels of greenhouse gases in atmosphere. In this context, it can highlight modern systems of electronic engine management, new automotive catalysts and use of renewable fuels that contributes to reducing emission levels of greenhouse gases into atmosphere [2]. This part is consolidated with increasing discovery of many renewable fuels, considered clean fuels [3]. Some time ago, vehicles are being equipped with devices that

2 596 Comparative Analysis of Gas Emissions from a Vehicle Running on Ethanol and Natural Gas Fuel allow m to use different types of fuels to promote a greater economy and a reducing of emission levels coming from internal combustion process in engines, as a way to attend legislation requirements and refore t0 preserve environment. This research aims to perform analysis of both of ethanol and physicochemical characterizations of natural gas fuel. We also aim to perform comparative analysis of gas emissions of a flex vehicle to urban cycle in a chassis dynamometer, running on ethanol or natural gas fuels to estimate maximum efficiency of automotive catalyst operating with different fuels. This paper is organized as follows: Section 2 addresses development; Section 3 presents results and discussion; and Section 4 brings conclusions. 2. Development 2.1 Vehicle Used in Tests The vehicle used to perform route of driving in urban traffic is a lightweight self-propelled road vehicle, engine 1.4, Flex model. 2.2 Gas Analyzer The gas analyzer applied to tests was used to determine concentrations of hydrocarbons, carbon monoxide, carbon dioxide and oxygen through electrochemical cell. The exhaust gas samples were collected in real time with support of probe for aspiration of gases, to determine concentrations in emission test, data was collected after and before catalyst for maximum catalytic efficiency test. 2.3 Ethanol The analysis of ethanol total characterization had physical structure of Fuels and LCL-UFRN (Lubricants Laboratory of Federal University of Rio Grande do Norte). 2.4 Natural Gas Fuel The completion of physical-chemical characterization analysis of natural gas fuel had physical structure of LQG-CTGÁS-ER (Quality Laboratory of Gas of Technology Center Gas and Renewable Energy). 2.5 Test Procedure Emissions It was elaborated a procedure for conducting emissions testing under simulated conditions of normal use average in urban traffic based on guidelines of NBR 6601, which prescribes method for determination of hydrocarbons, carbon monoxide, carbon dioxide, emitted by engine through discharge tube of a road vehicle propelled lightweight. The emissions test consists basically in determining concentrations of hydrocarbons, carbon monoxide and carbon dioxide from collection of emissions with gas analyzer, while vehicle performs a path coordinates of pre-established driving cycles, for such being necessary to use chassis dynamometer to simulate shooting actual conditions in runway. The emission test cycle in urban chassis dynamometer consists of two distinct parts: cold start and warm start, with a break of 10 ± 1 min between m [4]. Elaborate procedure for conducting tests: achievement test for determining emissions of hydrocarbons, carbon monoxide, carbon dioxide and oxygen in a Flex model vehicle, using driving cycles developed in chassis dynamometer, which simulates vehicle in urban traffic using fuel ethanol and natural gas fuel, for such dynamometer had to be fed with following variables: Equivalent inertia corresponding to total weight of vehicle: 1,304 kg; Aerodynamic drag of vehicle that is: 4.5 kw; Resistive power of chassis dynamometer which is: 0.3 kw Cold Start The cold start cycle requires 1,371 s (22 min and 51 s) to be fully invested being traversed a distance of approximately 12.1 km, this cycle is divided into two phases. The first phase, representing phase transient of cold start, which has a duration of 505 s

3 Comparative Analysis of Gas Emissions from a Vehiclee Running on Ethanol and Natural Gas Fuel 597 (8 min and 25 s) and being traversed a distance of approximately 5.78 km. The second phase, representing phase stabilized, is conclusion of test cycle, which has a duration of 866 s (14 min and 26 s), which is traversed a distance of approximately 6.32 km, ending with engine shutdown Warm Start Similarly, cycle of warm start is divided into two phases. The first phase, representing phase transient from warm start, which has a duration of 505 s (8 min and 25 s) and traversed a distance of approximately 5.78 km, while second phase of warm start cycle, representing phase stabilized is identical to second phase of cycle cold start, refore, test is not run, but considering values obtained in stabilized cold startt phase Coordinates of Urban Driving Cycle The driving cycle on chassis dynamometer, to simulate driving conditions in urban areas, is defined by a continuous graph of speed versuss time. It consists of not repeated sequences of slow running system, acceleration, cruising speeds and decelerations in magnitudes and varied combinations. The coordinates of this driving cycle ( 1) are specified in Table 1 of Annex B of NBR 6601 [4] Adequation of Urban Cycle Coordinates To be performed route proposed by NBR 6601, an adjustment of coordinates ( 2) was made, according to margin of tolerance on speed limits, which are allowed by this standard [5]. 3. Results and Discussion Following are results of total characterization analysis of ethanol in LCL-UFRN and physicochemical characterization of natural gas fuel in LQG-CTGÁS-ER. Also shown are results of tests conducted in LMA-CTGÁS-ER, where emissions were registered during performance of urban cycle. These results are shown in graphics that illustrate behavior of quantities involved in this study: contents of carbon monoxide corrected, hydrocarbons Velocity (Km/h) Velocity (Km/h) Coordinates of urban cycle emissions standard (NBR 6601) 5.78 km 1 Graphic coordinates of urban emissions standardd (NBR 6601). Adequation coordinates of urban cycle emissions standards 6.62 km 6.32 km 5.95 km 5.78 km 6.62 km 2 Graphic of appropriate coordinates of urban cycle emissions standards. corrected, carbon dioxide and oxygen for each of fuels used. It is still shown, by way of knowledge, results obtained for maximumm catalytic efficiency in a given moment, when catalyst is submitted to operation with each of fuels used Results Obtained from Analysis of Fuels Used The completion of total characterization analysiss of ethanol used in this work was supported by technical group and physical infrastructure of LCL-UFRN. The result of characterization analysis of ethanol is in compliance with ANP specifications and ir results are shown in Table 1. The completion of analysis of physical-chemicall characterization of natural gas fuel used in this work, had support of technical group and physical infrastructure of LQG-CTGÁS-ER. The result of analysis of physicochemical characterization of

4 598 Comparative Analysis of Gas Emissions from a Vehiclee Running on Ethanol and Natural Gas Fuel natural gas fuel is in compliance with ANP specifications and ir results are shown in Table Conducting Tests of Urban Cycle To perform test driving cycle of urban traffic, it was necessary to make adaptations in guidelines of NBR 6601, se adjustments were made taking into account velocity margin of tolerance which is permitted by rule, to make possible achievement of compliance coordinates of urban cycle [5]. The tests for determining emissions were performed in accordance with standard, which sets out methodology for simulation of driving a vehicle in urban traffic in chassis dynamometer using coordinates of speed versus time [6]. Sections show results of fixed hydrocarbon levels, carbon monoxide, corrected, carbon dioxide and oxygen residual, all present in emissions from combustion of ethanol and natural gas fuels, during driving cycle urban traffic Result of Corrected Hydrocarbon Contentt From results obtained in analysis of exhaust Table 1 Result of ethanol analysis. Technical features Ethanol Aspect Clear and free of impurities Color Colorless Specific masss (kg/m 3 ) (1) Alcoholic content ( INPM) 93.2 Electrical conductivity (µs/m) 190 Hydrogen potential (ph) 7.2 (1) measured at 20 C. Table 2 Result of natural gas fuel analysis. Technical features Natural gas fuel Superior calorific value (kj/m³) 38,180 Wobbe index (kj/m³) 48,750 Mehtane (% mol/mol) Ethane (% mol/mol) Propane (% mol/mol) Butane and heavier (% mol/mol) Inert (N 2 + CO 2 ) (% mol/mol) Nitrogen (% mol/mol) Relative density Specific masss (kg/m³) (1) (1) measured at 20 C. gases during testing of emissions driving in urban cycle traffic with flexible-fuel vehicles running on ethanol or natural gas fuel, it was performed a comparative analysis of average amount of corrected hydrocarbon content present in se gas emissions ( 3). The fuel which generated highest averagee corrected of hydrocarbon contentt present in gas emissions was natural gas fuel Result for Content of Carbon Monoxide Corrected From results obtained of exhaust gases analysiss during testing of emissions driving in urban cycle traffic with flexible-fuel vehicles running on ethanol or natural gas fuel, it was performed a comparative analysis of average content of carbon monoxide corrected present in se gas emissions ( 4). The fuel that generated highest average of corrected carbon monoxide content present in gas emissions was natural gas fuel. Result of corrected hydrocarbon content urbann cycle 3 Graphic with resultss of analysis of corrected hydrocarbon content. Result of corrected carbon monoxide content urban cycle 4 Graphic with resultss of analysis of corrected carbon monoxide content.

5 Comparative Analysis of Gas Emissions from a Vehiclee Running on Ethanol and Natural Gas Fuel Result for Content of Carbon Dioxide From results obtained of exhaust gas analysis during test emissions driving in urban cycle traffic with flexible-fuel vehicles running on ethanol or natural gas fuel, it was performed a comparative analysis of averagee of carbon dioxide content present in se gas emissions ( 5) ). The fuel which generated highest average content of carbon dioxide present in gas emissions was ethanol Result of Oxygen Conten From results obtained of exhaust gas analysis during test emissions driving in urban cycle traffic with flexible-fuel vehicles running on ethanol or natural gas fuel, it was performed a comparative analysis of averagee oxygen content present in se gas emissions ( 6). The fuel which generated highest average content of oxygen present in gas emissions was ethanol Results for Maximumm Catalytic Efficiency By way of knowledge, it was performed a comparative analysis in a given time for gas emissions collected before and after catalyst of vehicle, which resulted in maximum catalytic efficiency of catalyst used, analysis of test results when vehicle is submitted to operation in slow running with each one of fuels used are shown in Table 3. From point measurements of exhaust gases before and after catalyst, an estimate of maximum efficiency catalytic operating with ethanol or natural gas fuel was calculated, showing Result of carbon content urbann cycle Cold start Cold start 5 Graphic with results of analysis of carbon dioxide content. Results of oxygen content urban cycle 6 Graphic with results of analysis of oxygen content. Table 3 Resultss of maximumm catalytic efficiencies at a glance. Fuel Corrected Corrected carbon hydrocarbon monoxide (%) content (%) Ethanol Natural gas fuel best catalytic efficiency for reducing of corrected hydrocarbon content present in exhaust gases when vehicle ran on ethanol. To reduce concentrations of corrected carbon monoxide, efficiency was 100% and equal for both fuels. 4. Conclusion ns The values obtained for characterization analysis of ethanol, held at LCL-UFRN, was consistent with specifications of National Petroleum, Natural Gas and Biofuels Agency (ANP). The values obtained for analysis of physico-chemical characterization of natural gas, held in LQG-CTGAS-ER, was consistent with ANP specifications. The experimental methodology adopted in testt emissions attended proposed objectives, making possible achievement of conclusive results about emissions levels of vehicle running on different fuels. The results obtained from emissions recordedd during performance of urban cycle route, presented in a comparative analysis that: averagee of corrected hydrocarbon and corrected carbon monoxide levels, were biggest natural gas fuel,

6 600 Comparative Analysis of Gas Emissions from a Vehicle Running on Ethanol and Natural Gas Fuel average content carbon dioxide and oxygen content were highest to ethanol. The automotive catalyst showed best maximum catalytic efficiency for reduction of corrected hydrocarbon content when vehicle ran on natural gas fuel. The result for reduction of corrected carbon monoxide content was 100% for both fuels. References [1] Degobert, P Automobiles and Pollution. France: Institut Français du Pétrole Publications. [2] Nevers, N. 2000, Air Pollution Control Engineering. 2nd edition. New York: McGraw-Hill. [3] Bata, M. R Alternate Fuels, a Decade of Success and Promise. Morgantown: West Virginia University. [4] ABNT (Associacao Brasileira De Normas Tecnicas) Light Road Vehicles and Determination of Hydrocarbons, Carbon Monoxide, Oxides of Nitrogen, Carbon Dioxide and Particulate Matter in Exhaust Gas. NBR 6601 Standard. Brazil: Brazilian Association of Technical Standards. [5] Holanda, R. A Analysis of Gaseous Emissions from a Vehicle Flex Running with Different Fuels. master dissertation, State University Rio Grande do Norte. [6] Jacondino, G. B Quantification of Vehicle Emissions through Use of Traffic Simulators. master dissertation, University of Rio Grande do Sul. [7] Holanda, R. A., Laranja, G. C., Barbosa, C. R. F., Fontes, F. A. O., and Junior, C. R. F. B Comparative Analysis of Gas Emissions from a Vehicle Running on Ethanol and Compressed Natural Gas. Presented at 22nd International Congress of Mechanical Engineering, Ribeirão Preto, SP.