Ulisses Giacomini Frantz

Desempenho de motor de injeção direta sob misturas de biodiesel metílico de soja

The aim of this study was to evaluate the use of soybeans methyl biodiesel blends and diesel in an ignition compression engine with fuel direct injection. The tests were performed in a dynamometer bench, using the blends B10, B20 and B100 compared to the commercial diesel (B5). The engine performance was analyzed by tractor power take off (PTO) for each fuel. The best results obtained for the power and the specific fuel consumption, respectively, were: B5 (44.62kW; 234.87g kW-1 h-1); B10 (44.73kW; 233.78g kW-1 h-1); B20 (44.40kW; 236.20g kW-1 h-1) and B100 (43.40kW; 263.63g kW-1 h-1). It was concluded that the best results happened on the use of B10 fuel (more power in only 0.2% than fuel B5 and lower specific consumption in only 0.5% than B5). The B100 fuel showed significant differences compared to the other fuels (power lower 2.8% than B5 and more specific consumption in 10.9% than B5).

Eficiência operacional na colheita mecanizada em lavouras de arroz irrigado

The objective of this research was to evaluate the time efficiency and the field efficiency of the harvesting operation in rice fields, located in the region of Depressao Central of Rio Grande do Sul, Brazil. In the summer of 2008/2009, 19 operations were evaluated, being fifteen fields of them with land level and four without land level. The operation data were collected through the use of stopwatch, a clip board to record observations and with a signal receiver of GPS (Global Positioning System). There was no significant difference in the 5% level of probability of error between operations with land level and operations without land level. The field efficiency was calculated through the methodology used by GRISSO et al. (2002), and have been found the average of 65.2%, the time efficiency was determinate based on the concept of Hunt (2001), which have determined an average of 75.7%. Unload making combining with operation increase the field efficiency.

Transmissões presentes em tratores agrícolas no Brasil

The transmission system of an agricultural tractor has a main purpose to transmit the power generated in the hydraulic motor, the power take off and the drive wheels. The gearshift consists of a series of gears that allows the correct selection of speed and torque more appropriate to a particular operation. Then, the transmissions can be classified, basically, in three categories: mechanical, hydrostatic and hydrodynamic, being the mechanical transmissions subdivided in sliding gear and synchronized. Then, the objective of this research was to analyze the different types of transmissions available in 169 models of tractors made in Brazil in order to evaluate the real distribution of them in different power ranges and establish possible correlations. As a result, it was shown a strong tendency for agricultural tractors with power less than 111.8kW possessing mechanical transmission and tractors above 111.8kW possessing the hydrostatic type.

Distribuição dos comandos de operação em tratores agrícolas nacionais com até 55 kW de potência

This work aimed to compare the location of the operation controls in four new tractors in the range of 55 kW, John Deere 5603, Massey Ferguson 4275 New Holland TL75E and Valtra A750. As reference the standards ABNT/NBR ISO 4253 (1999) for determining the Seat Index Point (SIP), and ISO 15077 (1996) for determining the regions of range for the operator seated and the position of controls operation in reference to the SIP. In the analysis of longitudinal vertical profile, the frequently used controls were present in greater numbers in the Comfort Zone in the tractor Valtra A750 (38,5% of controls). In the same profile, the tractor John Deere 5603 showed 60,0% of its controls located within the Access Zone, which also showed the lowest percentage of controls in the Inaccessible Zone of the tractor (20,0% of controls). In the upper horizontal profile, the tractor Massey Ferguson 4275 showed 60,0% of its controls in the Comfort Zone, while Valtra A750 showed the highest percentage of controls located in the Access Zone and the lowest percentage in the Inaccessible Zone with 38,5 and 23,0%, respectively.

Efetividade de um coxim de cabina do trator agrícola na atenuação das vibrações

A vibracao propagada atraves do trator interfere diretamente no operador, desta forma, para minimizar os problemas e desejavel analisar os pontos criticos desta propagacao. O operador do trator esta exposto aos efeitos nocivos da vibracao na sua saude, alem de diminuir sua capacidade de trabalho por efeito da fadiga, sendo oportunas maiores investigacoes dos parâmetros de frequencia da vibracao nos coxins. Este trabalho teve por objetivo analisar a transmissibilidade das vibracoes no coxim elastomerico de um trator agricola com cabine utilizando duas profundidades de escarificacao (15 e 30 cm), duas velocidades de deslocamento (3,5 e 4,5 km h-1) e tres configuracoes de lastros (metalico total, metalico parcial e liquido total) com relacoes de peso/potencia de 49,5; 43 e 49 kg kW-1 respectivamente. O experimento foi realizado na Universidade Federal de Santa Maria com um delineamento de parcelas subdivididas. Utilizou-se um trator, com potencia no motor de 62,5 kW (85 cv), tendo um escarificador da marca Jan acoplado, os dados foram registrados atraves de acelerometros (Type 4513 B marca Bruel & Kjaer) instalados no piso da cabina, na plataforma e no coxim. Concluiu-se que a transmissibilidade de vibracao na direcao vertical atraves do coxim teve amplificacao no intervalo de 0 a 15 Hz para a Lastro metalico total, de 0 a 19 Hz para a Lastro metalico parcial e de 71 a 76 Hz para a Lastro liquido total.