apostas esportivas afun

Valéria Said de Barros Pimentel
Antônio Carlos Rodrigues Belchior
Silvio Carlos Anibal de Almeida
Department of Mechanical Engineering, Federal University of Rio de Janeiro
Ilha do Fundão, CT - sala G-204.Rio de Janeiro, RJ, Brazil. Postal Code 21.945-970.
Telefax 55-21- 2906626; Telephone: 55-21-2808832, E-mail silvio@serv.com.ufrj.br.

Marcos V. G. Nascimento
Leonardo dos S. R. Vieira
Guilherme Fleury
CEPEL/ELETROBRÁS

This paper presents several aspects about the use of palm oil as alternate fuel for diesel-generator. Preliminary studies of the state of the art of previous test results analysis are described. It follows the description of palm oil properties and characteristics used in investigation. The apparatus specification and test procedures are also presented. Performance and emissions data acquisition, general results and observation relevant to the diesel fuel are discussed. Lubricant oil contamination and combustion chamber, nozzle deposits formed and fuel pump wear are reported. Finally, conclusions and recommended future engine modifications are also included in the paper.

Keywords: Palm Oil, Combustion, Diesel Engines.
 
 

In a Diesel engine, 4 cylinder 3.9 liters, a great part of the original fuel is replaced by methane. Preliminary tests have shown that from 75 to 90% of the diesel can be substituted by the gas without loss of performance when compared to the original engine. The ignition, however, is only possible with a pilot flame from injected diesel. Since gas is already mixed with air, flame propagation is faster thus increasing pressure around two fold, thereby decreasing the life time of the engine. This work, thus, analyses the main parameters responsible for pressure increase and discuss some strategies to correct the problem and the consequences of such interference on the overall performance of the engine.

Keywords: Diesel Engine, Alternative Fuel , Biogas.
 
 

Eduardo Gagliuffi Peralta - eduardo@dem.ufrn.br
Centro Federal de Educação Tecnológica do Rio Grande do Norte - Unidade de Ensino de
Mossoró, Área de Eletromecânica, 59.628-330, Mossoró, RN, Brasil

José Guilherme R. R. Bastos - jguilherme@dem.ufrn.br
Cleiton Rubens Formiga Barbosa - cleiton@dem.ufrn.br
Universidade Federal do Rio Grande do Norte, Centro de Tecnologia, Departamento de
Engenharia Mecânica, 59.072-970, Natal, RN, Brasil

This work has the purpose to evaluate some characteristics of alcohol-diesel-castor oil blend fuel (three-components blend) for use in compression ignition engines. Castor oil was used as an additive and ignition improver. The blend fuels were obtained by a single process, in which known amount of components were mixed in a same container. Firstly, several solutions were prepared to achieve different percentage of alcohol content in castor oil, and the blend characteristics were determined. Secondly, for each type of solution, it was added the necessary amount of diesel fuel to achieve total blend solubility. The three-components blends were characterized in order to be compared to the properties of standard diesel fuel. The results obtained in this research, shows the possibility of applying these blends as alternative fuels to run compression ignition engines, without the need to make structural modifications.

Keywords: Blend fuels, Diesel/alcohol, Renewable fuel, Alternative fuel.
 
 

Gutierrez Jr., H.
Krieger, G. C. - guenther@usp.br
Tu, C.C-C
Universidade de São Paulo - Departamento de Engenharia Mecânica

The present work introduces a method for conducting the combustion process which allows high compression spark-ignited engines be operated efficiently using common fuels and without the need of any anti-knock compound addition. Considering the maximum cylinder pressure developed in the engine operating cycle, obtained at a referential and conventional compression ratio, the method consists on keeping that pressure constant as the compression ratio is increased. In addition, the resultant cylinder pressure curve profile, expressed in a pressure-volume diagram form, should be similar to an ideal limited pressure curve profile. Such an approximation can be done, for example, through the appropriate reduction in the spark advance as the compression ratio is incremented. When necessary, and feasible, it can also be done by adjusting some basic engine geometric factors and by changing the mixture turbulence level. In accordance to this method, experimental data on some engine performance parameters, obtained in a wide compression ratio range, are analyzed. It is shown that the operation of high compression spark-ignited engines, with the use of fuels with usual octane numbers, is thoroughly possible, free from the occurrence of knocking and, mainly, advantageous under the aspect of brake power and thermal efficiency.

Keywords: Compression Ratio, Limited Pressure Cycle, Knocking, Thermal Efficiency
 
 

Sérgio M. Hanriot - hanriot@pucminas.br
PUC-MG, Instituto Politécnico, IPUC
C.P. 1686-30535-610-BH, MG, Brasil

Ramon M. Valle - ramon@vesper.demec.ufmg.br
UFMG, Departamento de Engenharia Mecânica
Av. Antônio Carlos, 6627 - Campus Universitário
CEP 31.270-901 BH, MG, Brasil

Marcello A. Faraco de Medeiros - marcello@pucminas.br
PUC-MG, Instituto Politécnico, IPUC
C.P. 1686-30535-610-BH, MG, Brasil

The pulsating flow in the intake system of na internal combustion engine is studied. The study is both experimental and numerical and is aimed at improving the system performance. The pulsating phenomena originate from the periodic moviment of the intake valve. This produces waves that propagate within the system. The intake system studied was composed of a straigh pipe connected to a 1000cc engine with a single operating cylinder. The experiments were carried out in a flow bench. The numerical simulations used the method of characteristics. Mass flow and pressure fluctuations obtained from the numerical simulations compared very well with the experimental results.

Keyword: Engines, Resonance, Intake manifold, Flow-Bench
 
 

Everton Peter Carriconde - dcmc@agrale.com.br
Pedro Barbosa Mello - mello@mecanica.ufrgs.br
Universidade Federal do Rio Grande do Sul, Departamento de Engenharia Mecânica
Programa de Pós-Graduação em Engenharia Mecânica
R. sarmento Leite, 475 - 90035-972 - Porto Alegre, RS, Brasil

This work shows the influence of gasoline volatility in T10%, T50% and T90% ASTM D86 distillation points exerts on the dynamic performance of Otto cycle engines equipped with multipoint eletronic fuel injection system, using standard test procedures in a chassis dynamometer. For each one of the distillation points three ranges of temperature were established, forming 27 different kinds of gasoline. The effects of variation of those points in consumption, power and acceleration were verified individually.

Keywords: Volatility, T10%, T50% and T90%
 
 

Marcelo V. Feitosa - feitosausp@hotmail.com
Márcio T. Ávila - mtavila@sc.usp.br
Antônio M. Santos - asantos@sc.usp.br
Leônidas Hildebrand Jr.
Escola de Engenharia de São Carlos - Laboratório de Termodinâmica e Fluídos
Av. Dr Carlos Botelho, 1465, CEP 13560-970, São Carlos, S.P., Brasil

Daniela P.C. Silva - danielas@mailcity.com
Instituto de Química de São Carlos - Universidade de São Paulo
Av. Dr Carlos Botelho, 1465, CEP 13560-970, São Carlos, S.P., Brasil

Nowadays, ethanol is seen as one of the of the probable substitutes of the petroleum derived fuels. Its characteristics of renewable combustible, with low production of emissions and low toxic characteristic are factors that favor the use of the etanol in internal combustion engines, but cold start problems and poor engine operation during the heating period are negative factors. In this work the characteristics of the etanol as alternative fuel is analyzed. Still, t is proposed a method to determine the amount of fuel vapour produced during the intake process using values of temperature of the air inside the manifold. It is determined the influence of temperature and type of fuel used (ethanol or ethanol-gasoline blends) on cold start characteristics. Tests of success show us that air-fuel vapor ratios less than 150:1 always means success of the cold start.

Keywords: Cold start, Ethanol, Internal combustion engines, Ethanol-gasoline blends, Phases separation.
 
 

Marcelo V. Feitosa - feitosausp@hotmail.com
Márcio T. Ávila - mtavila@sc.usp.br
Antônio M. Santos - asantos@sc.usp.br
Leônidas Hildebrand Jr.
Escola de Engenharia de São Carlos - Laboratório de Termodinâmica e Fluídos
Av. Dr Carlos Botelho, 1465, CEP 13560-970, São Carlos, S.P., Brasil

Daniela P.C. Silva - danielas@mailcity.com
Instituto de Química de São Carlos - Universidade de São Paulo
Av. Dr Carlos Botelho, 1465, CEP 13560-970, São Carlos, S.P., Brasil

O etanol é visto ultimamente como um dos prováveis substitutos dos combustíveis derivados de petróleo. Suas características de combustível renovável, baixa toxicidade e de baixa produção de poluentes nocivos após sua queima são fatores que favorecem o seu uso em motores de combustão interna, porém problemas de partida a frio e de funcionamento irregular do motor durante o período de aquecimento são fatores que pesam negativamente. Nesse trabalho serão analisadas as características do etanol como combustível alternativo, proposto um método para determinar-se a quantidade de vapor de combustível produzido durante a admissão da mistura através de medições de temperaturas no fluxo de ar no coletor de admissão e determinada a influência da temperatura e do tipo de combustível utilizado (etanol ou misturas etanol-gasolina) nas características da partida a frio. Testes de sucesso ou falha da partida indicaram que razões ar-vapor de combustível inferiores a 150:1 no
coletor de admissão sempre implicam em sucesso de partida.

Palavras-chave: Partida a frio, Etanol, Motores de combustão interna, Misturas etanol-gasolina, Separação de fases.
 
 

Márcio T. Ávila - mtavila@sc.usp.br
Marcelo V. Feitosa - feitosausp@hotmail.com
Antônio M. Santos - asantos@sc.usp.br
Josmar D. Pagliuso - josmar@sc.usp.br
Universidade de São Paulo, Escola de Engenharia de São Carlos, Departamento de Engenharia Mecânica, Núcleo de Engenharia Térmica e Fluidos-NETeF, Laboratório de
Motores. Av. Dr. Carlos Botelho, nº 1465 - 13560-250. Fax: (016) 273-9402. São Carlos -S. P. - Brasil.

An Otto cycle engine, CFR model, was fueled with liquid and pre-vaporized ethyl alcohol. A heat exchanger utilizing the exhaust gases was used to vaporize the fuel alcohol. Data from the engine moved by liquid and vaporized alcohol were compared. The engine using vaporized alcohol presented greater thermal efficiency (+ 25%), softer operation and smaller fuel consumption (air/fuel ratios around of the value of 12/1) than the liquid version. Leaner operation was feasible with the vaporized fuel reaching an air excess up to 30%.

Keywords: Alcohols, Ethanol, Fuels, Internal Combustion Engines, Methanol.
 
 

Rinaldo Antunes Amaral - expmotor@fiat.com.br
FIAT Automóveis S.A., Engenharia de Motores
BR 381, km 429, 32530-000, Betim, MG
José Ricardo Sodré - ricardo@pucminas.br
PUC Minas, Departamento de Engenharia Mecânica
R. Dom José Gaspar, 500 - 30535-610 - Belo Horizonte, MG, Brasil

This work presents results and analysis of experiments on aldehyde emissions and on the regulated pollutants (CO, HC and NOX) emissions, with varying engine operational parameters in an ethanol-fuelled vehicle during a standard urban test cycle. The test cycle was carried out with the vehicle in a chassis dynamometer, and simulates an average urban trip of approximately 5,8 km, under steady state conditions. The varied parameters were fuel/air equivalence ratio, dash pot function, cut off function and gear change speed. The results found showed lower aldehyde emissions for gear change at lower speeds and for richer mixtures.

Keywords: Aldehyde Emissions, Ethanol Fuel, Internal Combustion Engine
 
 

André Luiz dos Santos , e-mail : als2000@tutopia.com.br
Narciso Angel Ramos Arroyo, e-mail : arroyo@sinmec.ufsc.br
Universidade Federal de Santa Catarina - Departamento de Engenharia Mecânica -Laboratório
de Combustão e Motores Térmicos - 88010-970 - Florianópolis - SC

This work is about heat balance of an automotive internal combustion engine of 4 cylinders, using ethylic alcohol, and utilize the energy obtained in the exhaust gas and the water cooling system. This paper show an theoretical - experimental model for use this energy in an absorption refrigeration system using the work fluid water and LiBr. In this paper are analyzed engines charges of 30%, 50% and 100%. The results shows that for this charges and for any speed of the engines, the energy obtained in the evaporator are significant.