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Revista Ciencias Técnicas Agropecuarias

versión On-line ISSN 2071-0054

Rev Cie Téc Agr vol.26 no.1 San José de las Lajas ene.-mar. 2017

 

Revista Ciencias Técnicas Agropecuarias, 26(1): 14-22, 2017, ISSN: 2071-0054

 

ORIGINAL ARTICLE

 

Traction Power and Gases Emitted by the Tractor MTZ -82 at Plowing Labor

 

Potencia traccional y gases emitidos por el tractor MTZ-82 en la labor de rotura

 

 

Dr.C. Yanoy Morejón-Mesa, M.Sc. Yanara Rodríguez-López, Dr.C. Roberto González-Valdés, Ing. Loise R. Castillo-Zangroni

Universidad Agraria de La Habana, Facultad de Ciencias Técnicas, San José de las Lajas, Mayabeque, Cuba.

 

 


ABSTRACT

This research was carried out on areas of the Agrarian University of Havana, with the objective of determining the power used in traction and gases emitted product of combustion in the plowing labor with the tractor set MTZ-82 and universal moldboard plows of three bodies. To achieve this objective the theoretical and methodological foundations were considered and the necessary measuring instruments were used to determine the reactions of the road on the wheels, the tractor dynamics of traction and the gases emissions produced by the combustion. Starting from the above stated, it was obtained that the biggest road reactions occur on the front wheels of the tractor reaching a value of 6,82 kN, being superior to those of the rear wheels 1,11 kN and wheel field 4,1 kN; the average depth of the work was 16 cm, reaching a mathematical expectation of the speed of 1,34 m/s and a mathematical expectation of the force exerted by the hook of 5,54 kN, being 28,4 L/ha the amount of fuel consumed; hook power reached a value of 7,42 kW, equivalent to 35% of the traction efficiency. In addition, 0, 67 kg of CO, 1,17 kg of CO2 and 0,98 kg of water vapor were ejected to the environment per liter of diesel fuel consumed (C12H26).

Key words: environment, combustion, reactions on the wheels, dynamic of traction.


RESUMEN

Esta investigación se realizó en áreas de la Universidad Agraria de la Habana, con el objetivo de determinar la potencia utilizada en la tracción y los gases emitidos producto de la combustión en la labor de rotura con el conjunto tractor MTZ-82 y arado de vertedera universal de tres órganos. Para cumplir este objetivo se plantearon los fundamentos teórico-metodológicos y se emplearon los instrumentos de medición necesarios para determinar las reacciones del camino sobre las ruedas, la dinámica traccional del tractor y las emisiones de gases producto de la combustión. A partir de lo planteado con anterioridad se obtuvo que las mayores reacciones del camino ocurren en las ruedas delanteras del tractor alcanzando un valor de 6,82 kN, siendo superior a las de las ruedas traseras en 1,11 kN y a la rueda de campo en 4,1 kN; la profundidad promedio de la labor fue de 16 cm, alcanzándose una esperanza matemática de la velocidad de 1,34 m/s y una esperanza matemática de la fuerza ejercida por el gancho de 5,54 kN, siendo la cantidad de combustible consumido 28,4 L/ha; la potencia del gancho alcanzó un valor de 7,42 kW, siendo esta equivalente al 35% de la eficiencia traccional. Además por cada litro de combustible diésel (C12H26) consumido se expulsan al medio ambiente 0,67 kg de CO; 1,17 kg de CO2 y 0,98 kg de vapor de agua.

Palabras clave: medio ambiente, combustión, reacciones sobre las ruedas, dinámica de tracción.


 

 

INTRODUCTION

At present, tractors are the main energy source used in agricultural farming; these are intended primarily for traction tasks.

The tractors are classified according to their traction class and from this and the work being performed, the agricultural joint can be formed in the most efficient way. That allows a group of agro-technical work in which the regime of exploitation varies. Therefore, to achieve the best traction and fuel economy results, it is necessary to determine or pre-calculate the parameters: mass, speed and power; this leads to a rational operation and a high degree of profitability.

Another element to be considered in the formation of agricultural joints, is that knowing the value of the resistance offered by the agricultural machine to the tractor, traction and energy indexes of the energy source can be selected, and for that purpose it is necessary to know the traction characteristics or effective parameters of the engine and its speed characteristics (Chudakov, 1977; Leyva et al., 2002; Mayans et al., 2010).

The trend in the preparation of soil from the twentieth century, both in Cuba and internationally, was oriented towards reducing the number of tasks, given the need to conserve natural resources and reduce production costs. Another tendency in this period was the use of agricultural machinery which does not invert the soil prism (Rodríguez, 1986; Olivet et al., 2012).

Soil preparation, among other factors, is determined by the soil type and means used in cultivation. In that sense, Borgman (1991) y Betancourt et al. (2007) reported that the application of minimum tillage should consider the properties of the medium to be transformed; and yet, in those with similar characteristics, differs agro-technical management.

Today’s agriculture is increasing strongly questioned by environmental and atmospheric pollution, intensive methods used worldwide for the production of food and the indiscriminate exploitation of land and forests, and inadequate agricultural sets forming. In Cuba, most of the agricultural work is done mechanically, so the level of emission of combustion gases into the atmosphere is greater; hence the need for proper formation of agricultural sets and the determination of their impact on the environment; specifically to determine the traction power and the emitted gases by the tractor MTZ-82 and the universal moldboard plow of three bodies in plowing labor.

 

METHODS

The research was conducted in areas of the Agrarian University of Havana, specifically in the experimental field of the Faculty of Agronomy. This area has a Ferrallitic Red Hydrated soil and it occupies a total area of 1 ha, the relief is slightly wavy, average soil moisture was 38,1% and it was determined by the gravimetric method, taking 25 samples to different depths. Bulk density was determined as 1,20 g/cm3 and also a specific gravity of 2,6 g /cm3. Both variables were determined by the cutting cylinder method, taking equally 25 samples to different depths. A weighing bottle, a digital balance with a precision of 0,01 g, a soil drill and stove were used to carry out the experiments.

Other instruments and materials used in the experiments:

-Tractor MTZ-82 with universal moldboard plow of three bodies;

-Tractor JUMZ-6M (tractor brake);

-Moldboard plow (with three organs);

-Measuring tape of 3 m with precision of ± 1mm;

-Digital scale with precision of ± 1kg;

-Portable gas analyzer PCA3 with precision of ± 5%;

-Dynamometer with precision of ± 0,1 kN

Methodology for determining the normal reactions of the road in the tractor wheels working with suspended agricultural machines

For the determination of the normal reactions of the road in the tractor wheels working with suspended agricultural machines, the lift capacity of the three-point rear hitch system was determined, for which the issues stated by Chudakov (1977), Srivastava et al. (1993), Linares (1996), Balastreire (2005), NC ISO 789-2: 2005 were considered.

The center of gravity and the shaft power of the agricultural set formed were also determined, for which NC ISO 789-6: 2005, y NC ISO 789-7: 2005 standards were used. In Figure 1 the reactions and forces in the agricultural joint during the work are showed and in Figure 2 the assembling between the main tractor and brake tractor is shown with the purpose of recording the forces in the tillage bar using a dynamometer.

Normal reactions of soil on tractor wheels are determined by the longitudinal and vertical coordinates aandh and of the tractor gravity center by the coordinates ar y hr of gravity center of the tractor with the implement.

where:

Ggr: weigh of suspended joint, kN;

Gs: weigh of suspended machine, kN;

as y hs: longitudinal and vertical coordinates of gravity center to suspended machine, respectively, m; α: angle respect to the horizontal.

Methodology for determination of traction dynamics and fuel consumption

To determine the traction dynamics of the joint in the plowing labor, a digital dynamometer model DILLON EDextreme with precision of ±0,01 kN was used. The ground breaking work was done at a depth that ranged from 15-20 cm in a Ferrallitic Red Hydrated, in third gear speed tractor, taken across a preset distance of 50 m.

To determine the fuel consumption of the set consisting of the MTZ-82 tractor and moldboard plow in the plowing labor, it was used the tank volumetric method, described in their research by Vázquez et al. (2012), for which a ruler or other calibrated instrument is required, so the control of the fuel volume change during operation is possible. The deposit must be horizontal and without dents.

The first step is the volumetric tank gauging. For that purpose a container with a capacity of 20 L is taken, that container is completely filled, poured into the fuel tank of the tractor and centimeters corresponding to the volume of fuel are marked in the millimeter rod previously selected. This operation is repeated until the tank is filled completely. Upon completion of the work, the amount of fuel in the tank is checked with the rod and it is subtracted from the amount initially serviced.

Methodology for determination of gases emitted from combustion

For the determination of gases emitted from combustion a portable gas analyzer PCA3 was used and its readings were confirmed through the foundations set by Faires y Simmang (1978); which stated in the case of a hydrocarbon, their chemical formulation can be defined by considering that other elements may be present, but only the sulfur is burned. In any case, it should be known if combustion is performed with the ideal amount of air or excess or deficiency of it. Knowing that, the products of a theoretical reaction can be determined. If the ideal or more air is supplied, H2O, CO2, and N2 are obtained, if there is an excess of O2, O2 is obtained in products.

If there is a deficiency of air, it is recognized that in the theoretical combustion all H2 burns up to H2O, due to the high affinity of oxygen for hydrogen and the C burns to CO and CO2, usually in unknown proportions. If there is sulfur, admitting that it reacts to produce sulfur dioxide (SO2), some of this product will react to SO3 and then in the presence of H2O it will produce sulfuric acid.

One of the products of combustion of a hydrocarbon is H2O. If the products are cooled to normal atmospheric temperature, most of this H2O is condensed, and the volume occupied by a liquid component is negligible compared to that of a gas. The fuel does not burn completely when it is not mixed with more than the ideal amount of air. In this case, some fuel molecules never find the needed oxygen. For complete combustion, some excess of air is needed, depending on the desired amount of the circumstances in the process.

 

RESULTS AND DISCUSSION

Determination of normal reactions of the road on the tractor wheels working with suspended agricultural machines

Among the main results, normal reactions of the road on the wheels of the tractor MTZ-82 and on the moldboard plow were determined, to get values of 33,7 kN and 2,3 kN, respectively. These values, along with the identification of the geometric coordinates of the aggregate formed, made possible the calculation of normal reactions above mentioned, considering the fundamentals stated by Chudakov (1977).

These results were validated with the determination of the inflation pressure of tires (front and rear) and the mark left on the road1, having similar results for both ways of solution, with a precision of 10%, using in these experiments a analogic manometer with an appreciation 100 kPa and a 3 m measuring tape with precision of ±1mm .

In table 1 it is shown that the biggest reactions of the road occur in the front wheels of the tractor, which is given by the stability to be achieved while the ground is ploughed. For field wheel, reactions were inferior, which was given by the resultant force of the working tool (ploughshare) that reached a value of 1,85 kN and the angle of inclination to the horizontal. In addition, reactions arms in relation to the instantaneous center of rotation of the machine suspended reached values of 0,56 m and 0,38 m, respectively. These values were obtained during the regulation of the implement before plowing agricultural work and by using the measurement instruments above described.

Determination of traction dynamics and fuel consumption

As a result of the traction dynamics of the aggregate MTZ-82 with moldboard at plowing labor, the behavior of the speed and the force exerted by the hook added, depending on the depth of the work was obtained.

It was observed that the average depth of the work was 16 cm, the expected value of the travel speed of the aggregate was 1,34 m/s and the expectation of the force exerted by the hook was 5,54 kN. The behavior of these variables depending on the depth of the work is shown in Figures 3 and 4.

In Figure 3 the relationship between the speed developed by the set and depth of tilling is observed, showing that as depth increases, speed decreases, as the relationship between both variables is inversely proportional. The maximum depth achieved in the work was 20 cm at a speed of 1,09 m/s and the minimum depth developed obtained was 13 cm in which a speed of 1,67 m/s was developed. As the working depth increases, increases the resistance of the working tools to penetrate the soil. That increases the strength of the agricultural machine, requiring greater force on the hook to ensure the movement.

In Figure 4 the relationship between the force exerted on the hook set and depth of tilling is displayed, showing that as depth increases, the strength of the hook increases, behaving in a directly proportional relationship between the two variables.It is observed that for the maximum depth reached in the work, a force of 8 kN was exerted on the hook and for the minimum depth obtained, a force of 4 kN was exerted on the hook.

Knowing these values, the balance of power and traction characteristics is performed, resulting in the power of the hook, which is the product of the force exerted on the hook and the speed developed by the aggregate, reaches a value of 7,42 kW.

Knowing the real power exerted on the hook, the traction class of tractor MTZ- 82 (14 kN) and the speed to be achieved by the joint in this work (that is 1,52 m/s in third gear, according to the manufacturer’s specifications), it is possible to obtain the nominal power of the aggregate which amounts to 21,31 kW. That makes possible to determine the traction efficiency of the whole, which reaches a value of 35% and it is below the allowable minimum efficiency values for this type of work, that are between 60 and 70% as stated by several specialists on the topic (González, 1993).

The values obtained for the traction efficiency are directly related to the years of operation of the tractor as it is an equipment of more than 20 years, which has not received the technical maintenance works with the required frequency. Another influential aspect is the poor condition of its tires, aspect that directly affects the skating experienced by the joint in the plowing labor that reached a value of 12%, which is high and demonstrates its direct influence on traction.

The amount of fuel consumed was determined by using the method of volumetric tank. It reached a value of 28,4 L/ha, being within the range established for this set that is from 24 to 32,4 L / ha, despite the conditions in which the tractor is (González, 1993).

Determination of gases emitted from combustion

From the amount of fuel consumed in the work, that was 14,2 L, and knowing that the bulk density of it is 0,72 kg / L, the mass of fuel spent was determined and it was 10,2 kg.

According to its characteristics this fuel was classified as a hydrocarbon in octanes order (C12 H26), whose the molar mass is 170 kg/kmol, thus it is possible to determine the amount of this substance that burns during the combustion, which is 0,06 kmol. For the determination of the combustion products a coefficient of air excess minor than 1 was taken, specifically equal to 0,85, given that the tractor used in the investigation did not have a turbocharger. Therefore, the amount of air required for combustion was insufficient, so it resulted in an incomplete combustion and a rich air-fuel mixture, which means that all fuel introduced in the combustion chamber does not burn. That is shown in the combustion represented below where it is possible to observe the values of quantity of substance (n), relative volume (V) and mass (m) of each component (Figure 5).

As it is shown in the final combustion obtained, 9,52 kg of CO; 16,72 kg of CO2 and 14,04 kg of water vapor are ejected to the environment with a negative impact on it due to the incomplete fuel burning. These results show that for every liter of diesel fuel (C12H26), 0,67 kg of CO; 1,17 kg of CO2 and 0,98 kg of water vapor are discharged to the environment.

These gases emitted to the atmosphere increase the greenhouse effect, contributing to the deterioration of the ozone layer and polluting the air breathed by human beings.

 

CONCLUSIONS

The theoretical and methodological foundations stated evidenced that the major road reactions occur on the front wheels of the tractor reaching a value of 6,82 kN, being superior to those of the rear wheels in 1,11 kN and of the field wheel in 4,1 kN.

The average depth of the work was 16 cm, reaching a mathematical expectation of the translational speed of the set of 1,34 m/s and an expectation of the force exerted on the hook of 5,54 kN, being the amount of fuel consumed of 28,4 L/ha of tilled land.

The power of the hook reached a value of 7,42 kW, yielding a traction efficiency of 35%, which is below the allowable minimum efficiency values for this type of work that are between 60 and 70%.

For each liter of diesel fuel (C12H26) consumed 0,67 kg of CO; 1,17 kg of CO2 and 0,98 kg of water vapor were expelled to the environment.

 

NOTES

1 Catálogo de tractores Belarús MTZ-80 y MTZ-82, Moscú, URSS, 1979.

*The mention of commercial equipment marks; instruments or specific materials obey identification purposes, not existing any promotional commitment with relationship to them, neither for the authors nor for the editor.

 

BIBLIOGRAPHY

BALASTREIRE, L.A.: Máquinas Agrícolas, [en línea], Ed. Manole, Sao Paulo, Brasil, 310 p., 2005, ISBN: 85-900627-1-6, Disponible en: http://www.pldlivros.com.br/MaisProduto.asp?Produto=89, [Consulta: 26 de noviembre de 2016].

BETANCOURT, Y.; RODRÍGUEZ, M.; LEÓN, O.L.; GUTIÉRREZ, A.; GARCÍA, I.: “Variantes tecnológicas de laboreo mínimo para la plantación de Caña de Azúcar en los suelos de mal drenaje del Norte de Villa Clara”, Revista Ciencias Técnicas Agropecuarias, 16(4): 53–57, 2007, ISSN: 2071-0054.

BORGMAN, J.: “Acerca de la metodología de investigación para experimentos tecnológicos de gran escala en la preparación del suelo para el cultivo de la caña de azúcar en Cuba”, Revista Ciencias Técnicas Agropecuarias, 3(1): 57–68, 1991, ISSN: 2071-0054.

CHUDAKOV, D.A.: Fundamentos de la teoría y el cálculo de tractores y automóviles, [en línea], Ed. MIR, Moscú, 435 p., 1977, Disponible en: http://www.sidalc.net/cgi-bin/wxis.exe/?IsisScript=UACHBC.xis&method=post&formato=2&cantidad=1&expresion=mfn=014804, [Consulta: 26 de noviembre de 2016].

FAIRES, V.M.; SIMMANG, C.M.: Thermodynamics, Ed. Macmillan, 6.a ed., New York, 647 p., 1978, ISBN: 978-0-02-335530-1.

GONZÁLEZ, V.R.: Explotación del parque de maquinaria, Ed. Félix Varela, La Habana, Cuba, 497 p., 1993, ISBN: 978-959-07-0028-6.

LEYVA, O.; PARRA, L.R.; SERRANO, M.; GASKIN, B.: “Valoración de la reducción de la resistencia traccional de los órganos de trabajo de un escarificador vibratorio”, Revista Granma Ciencia, 6(2), 2002, ISSN: 1027-975X.

LINARES, A.P.: Teoría de la tracción de tractores agrícolas, Ed. Departamento de Publicaciones de la Escuela Técnica Superior de Ingenieros Agrónomos, Madrid, 157 p., 1996, ISBN: 978-84-7401-141-8.

MAYANS, C.P.R.; SOCA, C.J.R.; LÓPEZ, C.G.; ROMANTCHIK, K.E.: “Determinación de la fuerza de tracción y potencia a la barra de tiro del tractor New Holland 6610s”, Revista Ciencias Técnicas Agropecuarias, 19(1): 63-69, 2010, ISSN: 2071-0054.

OFICINA NACIONAL DE NORMALIZACIÓN: Máquinas agrícolas y forestales – tractores agrícolas – procedimientos de ensayo – parte 2: capacidad de levante del sistema de tres puntos, no. NC ISO 789-2, La Habana, Cuba, 2005.

OFICINA NACIONAL DE NORMALIZACIÓN: Máquinas agrícolas y forestales – tractores agrícolas – procedimientos de ensayo – parte 7: potencia del eje del agregado, no. NC ISO 789-7, La Habana, Cuba, 2005.

OFICINA NACIONAL DE NORMALIZACIÓN: Máquinas agrícolas y forestales–tractores agrícolas– procedimientos de ensayo – parte 6: centro de gravedad, no. NC ISO 789-6, La Habana, Cuba, 2005.

OLIVET, R.Y.E.; ORTIZ, R.A.; COBAS, H.D.; BLANCO, B.A.; HERRERA, G.E.: “Evaluación de la labor de rotura con dos aperos de labranza para el cultivo del boniato (Ipomoea batatas Lam) en un Fluvisol”, Revista Ciencias Técnicas Agropecuarias, 21(4): 24-29, 2012, ISSN: 2071-0054.

RODRÍGUEZ, R.: “El laboreo mínimo de suelos”, Boletín de Reseñas, ser. Mecanización Agropecuaria, (3): 48, 1986, ISSN: 0138-8681.

SRIVASTAVA, A.K.; GOERING, C.E.; ROHRBACH, R.P.: Engineering principles of agricultural machines, ser. ASAE textbook, no. ser. 6, Ed. American Society of Agricultural Engineers, St. Joseph, Mich., 601 p., 1993, ISBN: 978-0-929355-33-7.

VÁZQUEZ, M.H.B.; PARRA, S.L.R.; SÁNCHEZ-GIRÓN, R.V.M.; ORTIZ, R.A.: “Análisis de la productividad y el consumo de combustible en conjuntos de labranza en un fluvisol para el cultivo de la yuca (Manihot esculenta, Crantz)”, Revista Ciencias Técnicas Agropecuarias, 21(2): 38-41, 2012, ISSN: 2071-0054.

 

 

Received: 15/10/2015
Approved: 14/11/2016

 

Yanoy Morejón-Mesa, Prof. Auxiliar. Universidad Agraria de La Habana, Facultad de Ciencias Técnicas, San José de las Lajas, Mayabeque, Cuba, CP: 32700. Email: ymm@unah.edu.cu

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