Giovanni Molari

VINEYARD EVALUATION OF A RECYCLING TUNNEL SPRAYER

This article presents the results of field trials of an air-assisted tunnel sprayer with a recycling system for the liquid that is not retained by the leaves. Its characteristics and performance, in terms of distribution quality and losses to the soil, were compared with a conventional air-blast sprayer. The trials were done in a vineyard trained to spur-pruned cordon at two growth stages using a fully randomized experimental design. The results show that losses to the ground with the tunnel sprayer were less than 5% of the sprayed liquid in both growth stages, which are much lower than those of conventional sprayers. The amount of liquid retained by the leaves was about 87% of that distributed in both stages. Biological tests carried out during the season showed no significant difference between the sprayers in terms of efficacy. The overall results point out that the tunnel sprayer using this type of air-circulation system requires much less chemical product and shows higher environmental sustainability in comparison with conventional air-blast sprayers.

Recycling tunnel sprayer for pesticide dose adjustment to the crop environment

The article presents the results of field trials of an air-assisted tunnel sprayer with recycling of the liquid not captured by the foliage. The influence of leaf density and spray flow rate on plant and ground deposits was studied. The trials were repeated on a spur-pruned, cordon-trained vineyard spraying the same flow rate at three growth stages; three flow rates were then compared in the last stage test. Liquid losses to the ground were less than 2% of that sprayed in every combination of vine growth stage and spray flow rate. When operating beneath the dripping limit, canopy density and flow rate did not affect losses, which totaled about 8% of the liquid sprayed. These results could be used in real treatments to calculate the amount of liquid retained by the plants simply by measuring the amount of spray recycled by the machine along a known path. This would allow a highly precise distribution of the required dose in a single spraying at a specific growth stage. As in previous trials, the recycling tunnel sprayer showed high environmental sustainability compared to traditional machines.

Evaluation of the Frequency Response of Tractor Cab Angular Movements

The mission profiles of tractors have been modified recently due to a rise in their use as transport vehicles. This use of the tractor together with an increasing maximum velocity on the road emphasizes the containment problem of the vibration transmitted to the driver. In particular, a significant contribution to the increasing global vibration level transmitted to the driver is given by low-frequency movements. Recent work has demonstrated the capability of the ISO standards used for tests in the automotive sector to characterize the dynamic behavior of tractors. In this work, one test, derived from the ISO standards mentioned above, was used to evaluate the capability of the suspension system to isolate the cab from the angular oscillations coming from the driveline. In particular, the frequency response of the cab angular movements was measured on two tractors, with and without an implement connected to the three-point linkage, and was compared with that measured on the tractors driveline. The results showed a considerable amplification of the roll from the driveline to the cab, particularly with an implement, and a negligible amplification of the yaw.

Evaluation of a Tractor's Driving Performance on the Road

In recent years, tractor use on the road has increased, in part due to a higher maximum velocity allowed. An increase in velocity highlights certain limits of the vehicle in terms of driveability and comfort. Numerous studies regarding the standards of on-the-road behavior exist in the automotive sector. On the contrary, there are no studies concerning the on-the-road behavior of tractors but, rather, only off-the-road studies with the objective of developing steering systems that facilitate the driveability of the vehicle. The objective of this article is to discuss tests that allow the characterization of a tractors steering system and its behavior on the road. The tests were performed on two tractors with the same power rating but different steering systems. The tests were carried out using the standards of the automotive sector but with some changes: a decrease of the traveling velocity, the lateral acceleration, and the maximum frequency of the steering action. Different parameters characteristic of the steering system were analyzed under lateral acceleration of the tractor while steering to make a turn with a constant velocity and when the system was excited in a transient manner. The global behavior of the tractor on the road and, in particular, the characterization of steering system quality are presented.

Dynamic Analysis of Reciprocating Single-Blade Cutter Bars

In this study, a mathematical lumped mass model for a reciprocating single-blade cutter bar with a slider-crank mechanism was developed. The equation of motion was numerically integrated, and the influence of geometric, kinematic, dynamic, and biological parameters was investigated. The analysis demonstrated the uselessness of the crank disc inertia and pointed out that system imbalance is due more to the periodic instability of motion and torque than to the alternative inertia force of the blade. The analysis also showed the existence of an optimum running speed that minimizes instability, and thus imbalance, and that cutting resistance decreases as the running speed increases. It is therefore possible to find a functional optimization of the system with regard to vibratory phenomena and cutting quality.

Experimental Evaluation of the Soil Pressure Distribution on Plough Parts

Ploughing is one of the most popular and energy-consuming process among conventional tillage treatments. Ploughing tool is worn down during the interaction with soil. This effect increases the tractor fuel consumption, tillage quality, and maintenance costs due to higher replacement rate of tool parts. In this paper a methodology for the measurement of the pressure distribution generated by the soil on plough components is introduced. Field tests were carried out with a four-furrow plough at different speeds and ploughing depths. Pressure on the different parts of the working body was measured with tactile sensors protected through a suitable PVC layer. The analysis of the results shows that the higher mean pressure values are located on the mouldboard and on the wear plate. Moreover, the vehicle speed affects the mean pressure values and in particular, each part of the plough has a different behaviour. The evaluation of the pressure produced by the soil on ploughs is useful for improving the comprehension of the soil cutting process and consequently to design ploughs with higher wear resistance.

Evaluation of Oil Flows for the Lubrication of an Agricultural Tractor Transmission

An important part of power losses in tractor transmissions is due to the oil they contain. To limit power losses, a reduction in oil level in the tractor drive train is necessary, while still ensuring lubrication of the individual components. In this article, oil flows sufficient for the lubrication of gears and bearings in a full power-shift transmission front box were calculated. After evaluation of individual element power loss in the worst working condition, a thermal balance and the oil flow required to eliminate the produced heat were calculated. Gear lubrication requires about 10 L min-1, while rolling bearings need about 2 L min-1. Two gear jet flow lubrication systems were then evaluated and the most important parameters established for correct nozzle positioning.