With all the restrictions that Rio Grande do Sul is facing for air transport, resulting from the recent floods and the closure of the main airport, Salgado Filho, in Porto Alegre, the team from Revista Cultivar Máquinas and the UFSM Agrotechnology Laboratory took a trip of more than 20 hours to Dois Vizinhos, in Paraná, to see, in the field, how the Accura 8.0 HD fertilizer distributor works.
But all this effort was worth it. It was very interesting to work with a fertilizer distributor, first because of the quality of the product, but also because of the test conditions. We took advantage of the opportunity of a demonstration of machines for customers and those interested in Kuhn equipment promoted by Silva Máquinas Agrícolas, a Kuhn dealer in Dois Vizinhos, and the following day, with all the structure, we carried out our evaluation day. These demonstrations are part of a Kuhn campaign, called Perfect Fertilization, to present the Accura line of machines in various regions of the country.
The spreader we tested, the Accura 8.0 HD model, was launched in 2022, with sales starting the following year. It is a piece of equipment developed for the Brazilian market, suitable for large-area agricultural systems.
The equipment is clearly seen as a set between a vehicle and the fertilizer storage, dosing and distribution devices. As for the vehicle, it uses the same structure as the Stronger HD self-propelled sprayer, produced in Brazil by Kuhn, with only one difference, which is the electronic part designed and updated for a solid product distributor.
On a solid chassis, in front of the front axle, there is a cradle for the engine. On the rest, two side members support the other components, such as the main tank, and at the end, behind the rear axle, the most important part of this equipment, which is the CDA, or coaxial distribution adjustment, responsible for dosing and distributing the fertilizer. The arrangement of the Accura 8.0 HD components was designed to maintain a balanced distribution of weight on both axles, which is why the engine was placed in a forward position in relation to the cabin.
To facilitate the application of products on already established crops, the free space was set at 1,60 meters from the ground surface to the lowest plane of the spreader and the gauge, which is the horizontal distance between the center of the wheels on the same axle, and can vary from 2,80 to 3,50 meters, with opening and closing through a hydraulic drive mechanism. After releasing the limiting locks, the operator starts moving at reduced speed and, from his operating position, begins the procedure of opening or closing the gauge to the desired dimension. Then, just replace the locks and the operation is complete. The gauge will be the customer's decision, adapting the equipment's track to that of the other machines, especially if controlled traffic is used, or increasing the gauge, if the terrain slope is large and what is needed is greater stability of the set. The minimum gauge is 2,80 m.
The equipment has a total length of 9,33 m, a total height of 4,24 m and a wheelbase of 4,0 m. The tires used are radial type in the VF 380/90R46 specification, with a tubular line opener, which can be faired, as an option. To adapt the vehicle to the irregularities of the terrain, absorbing the undulations and roughness, the Accura 8.0 DH has an independent and active pneumatic suspension, which uses air bags in each position close to the wheel.
The engine that equips the Accura 8.0 HD is an MWM 6.12 TCE model with six cylinders and a displacement of 7.200 cm³, which provides a maximum power of 280 hp at a rotation of 2.200 revolutions per minute and a maximum torque of 1.200 Nm at 1.300 rpm. The engine uses a turbocharger with aftercooler and the fuel injection system is electronic with a "common rail", programmed to provide extra power, a "booster", in case of temporary need. On the side of the chassis and below the main tank is the fuel tank made of aluminum and painted in black. This tank has a capacity of 400 liters and is filled through an inlet behind the cabin and next to the inspection window and viewing of the level of the main fertilizer tank.
The engine power is transmitted to the rest of the equipment by a Bosch model A4VG Series 32 pump, placed at the rear outlet of the engine. From there, the hydraulic oil flow goes to the wheel motors, Bosch Rexroth model A6VE Series 65, which have the well-known and efficient Bonfiglioli 606W 2 VH wheel reducers. To improve the vehicle's balance while moving and solve problems of loss of grip during operation, an interesting automatic wheel movement blocking system was installed, using an inductive sensor to measure the peripheral speed of the wheels. Whenever one of the wheels loses grip and slips more than the others, the electronic system is warned and the blocking is performed, modifying the oil flow for four seconds each time, restarting whenever necessary.
The Accura 8.0 HD has two fertilizer tanks, the first for storing the product to be applied and the second for control, which will be used for dosing and application. Therefore, unlike other distributors, the flow of product to be applied does not come directly from the end of the conveyor belt to the dosing and distribution mechanisms.
The main fertilizer tank has a capacity of 8 liters and is made entirely of stainless steel to minimize the effects of corrosion caused by the presence of saline components in the products to be applied. This measure has been the most effective among other alternatives, such as special coatings, for example. At the bottom of the tank, which is shaped like a wide wedge, there is a flat roller conveyor belt made of polymer, with roller tensioners and an inspection and cleaning window on the bottom. To drain possible product losses during transportation and movement of the conveyor belt, pipes were installed to allow these small quantities to pass to the ground, preventing them from remaining in contact with the machine. In the upper part of the main tank, the project included a protective grid to prevent the entry of foreign objects, especially during filling, which can be easily removed, and a canvas to close the upper part, operated by means of a system of cables and tensioners.
To support the supply and monitor and perform any operations on the tanks, the manufacturer placed a platform with a hollow floor made of a plastic material covered with fiberglass on the left side of the vehicle. This process of building plastic profiles used in situations that require great resistance is called pultrusion, and for this reason, the platform floor is called pultruded. It is a highly innovative industrial process that provides lightness and resistance, while also providing easy self-cleaning. At hand height, there are side supports along the entire length of the platform, as required by applicable safety regulations for agricultural machinery and equipment.
In our opinion, the CDA, coaxial distribution adjustment, consisting of the control tank, a movement transmission to the discs, with central drive and from there to the two discs, is the most important component of this machine. The control tank has a capacity of 125 liters, is covered by a fairing and has a hinged lid for closing during work.
There are two inductive sensors at the back of the control tank that determine the level of the reservoir and, with this information, control over the movement of the main reservoir conveyor belt. Unlike other machines, in which the conveyor belt remains in motion, in this Kuhn equipment the conveyor belt moves only to promote the filling of the control tank. If the level of this reservoir is high, the conveyor belt remains static until the sensor reading indicates the need to replenish the product. This is a difference in relation to conventional projects that exist in the country.
At the bottom of the control tank, an agitator acts on the gates, promoting the movement of the fertilizer without crushing it. The gates have an opening profile for the beginning and end of the dose that will fall onto the disk. The action of the flow control scale determines the deposition position (fall point) of the fertilizer, which ends up determining the useful width range for each product.
On the other hand, an electronically driven actuator opens and closes the gate, establishing the dose to be applied, including allowing for the placement of varied doses, according to application maps that can be used on the Trimble monitor. Just above the discs, a brush protects the product from the wind and helps the fertilizer fall at the right point, marked on the flow control scale.
Finally, a pair of discs is responsible for receiving the product flow and carrying the energy particles for launch in a ballistic trajectory, which will establish the working width for each dose and type of fertilizer. The two discs have a unique shape, close to conical, and have long fins. Unlike some competing machines, the disc fins on the Accura 8.0 HD are fixed, eliminating those complex and often unnecessary adjustments.
The manufacturer offers four disc options for this model of spreader, S6, S8 (standard), S10 and S12, which are related to the product being applied and the working width (24 to 42 m), which will be informed in the calibration protocol, which does not include limestone or agricultural gypsum. All this technology, which is in fact the heart of the machine, was designed by Rauch and several of the components come from abroad to guarantee quality.
The Accura 8.0 HD self-propelled spreader is very easy to operate. Once the main tank is filled, the Trimble monitor is used to configure the task to be performed, determining the target dose to be applied. Using a fertilizer identification guide, the pattern on the commercial product in the tank should be compared with the pattern shown in this guide. Once the pattern has been chosen from among the various patterns presented, the configuration will indicate the type of disc and the application width that should be considered to establish good overlap and achieve a homogeneous distribution pattern with a low coefficient of variation. All of this configuration is done using software developed by Rauch, installed on the main monitor.
From there, it is just a matter of configuring the Trimble autopilot, with Danfoss orbital. The controller is the recently developed NAV-900, which provides good precision, even in the autonomous system, although Kuhn offers and provides RTX signal opening, if the customer wishes.
Once the application and autopilot are configured, simply turn on the application system and the machine will automatically increase the engine speed and establish the ideal application speed using the continuous transmission, which can be increased and reduced using the multifunction control, located on the console to the right of the operator.
Eventually or when the operator deems it necessary, the monitor screen can be used for later viewing, with the rear camera.
Access to the Accura 8.0 HD distributor cabin is via a seven-step ladder placed at the front of the machine and aligned with the left side platform. At the end of the ladder, a door provides access to the operator's station, which has a main seat with pneumatic cushioning and automatic adjustment. On the left side, there is a passenger seat.
The steering column is adjustable and can be brought closer to the operator after he or she enters the machine. To the right of the operator, connected to the seat, there is a side console with armrest and a keyboard for controlling various functions, and a general safety switch to stop the movement if necessary. There are also places for frequently used objects. In front of the console and connected to it, there is the Lohr automation monitor, which controls the machine functions.
The Trimble GFX 1060 monitor was placed on the left side column, which has an on-touch screen divided into programmable virtual rectangles that contain basic information such as GNSS, the signal precision system, the vehicle profile, the distributor and the product to be applied, the target area and the task. A series of configurations can be made according to the operator and their way of working. This monitor is the same as the one used on the self-propelled sprayer and can be placed on as many machines as the customer wishes, in addition to which all the files generated can be easily exchanged and communication is via Bluetooth and Wi-Fi.
Once work has started, the monitor will show the position of the machine in the field and shade the areas already applied.
The field test was conducted in a rural area near the city of Dois Vizinhos, in the state of Paraná. This area was set up for a day of demonstrations of Kuhn machines and was covered with cover crop straw, predominantly oats. We conducted the tests by making passes adjacent to an AB line, in the direction of the longest length of the plot, previously traced by the machine's automatic pilot system. We were supported in this test by engineer Luis Guilherme Lemes, a product specialist for spreaders and sprayers, and Josemar Teixeira, a Kuhn machine technician who is responsible for training and technical deliveries to support the brand's dealerships.
Kuhn is a global company with 196 years of experience in agriculture. With eleven factories and numerous distribution centers spread throughout the world, it is present in the Americas, Oceania, Europe and Asia. In Brazil, it has two parts production and distribution units, one in São José dos Pinhais, Paraná, and another in Passo Fundo, Rio Grande do Sul, in addition to two parts distribution centers in Palmas, Tocantins, and Rondonópolis, Mato Grosso.
Across the country, the brand has Prime dealers with parts and services with Kuhn quality control that sell the entire agriculture and livestock portfolio.
In the test region, the Prime reseller is Silva Máquinas Agrícolas, which works with the entire product line.
In addition to the Dois Vizinhos store, Silva Máquinas Agrícolas has another in Realeza, and more recently opened a third store in Laranjeiras do Sul, serving the entire important southwest region of Paraná.
Kuhn's portfolio is huge and includes a line of seeders, sprayers, fertilizer spreaders, bulk trailers, decompactors, haymaking machines such as mowers, spreaders, windrowers, balers, packaging machines and, for livestock farming, mixing wagons and manure spreaders.
Specifically, the family of sprayers we tested includes three types, the first for mounting on the three points of the tractor hydraulic system, Accura 1200 and Accura 1600. The second type for coupling to the drawbar, which are the Fertiline 8000, Accura 10000 and Accura 12000/15000 and, finally, the self-propelled sprayers, Accura 4.0 BX, Accura 7000 ST and the one presented in this test, the Accura 8.0 HD.
After performing the test, making several passes, viewing all the controls and applying potassium, our assessment of the machine and its performance was very positive. From a mechanical point of view, the machine is very well built, with materials and components joining resources that are very well developed and innovative for the standard that exists in the national market. Care and attention to detail can be seen in the assembly of the machine, in the arrangement of the electrical wiring and hydraulic hoses, in addition to the finishes and components of the operator's station.
Regarding the application's adjustment and calibration, we understand that the manufacturer sought to equip the machine with a level of technology that was just right for its needs, without inserting electrical and electronic components that were not absolutely necessary. Many consumers of modern equipment complain about unexpected shutdowns due to the large number of components that stop working and the complexity of configuring their machine. In this case, there are only two sensors, those that measure the speed of the wheels and rely on the hydraulic system to prevent the wheels from slipping, and the ultrasonic sensors that measure the level of the control reservoir and control the actuation of the main reservoir's conveyor belt, and a Speedservo actuator that instantly establishes the dose to be applied, opening and closing the gate.
As for the adjustment and calibration system, which is innovative and partially replaces the traditional system of placing and weighing trays, it can help the customer obtain a configuration based on Kuhn's experience. In short, it was a good experience to see and see the field work of this machine and to test a self-propelled fertilizer spreader, an activity rarely carried out in these 20 uninterrupted years of testing with Revista Cultivar Máquinas.
Jose Fernando Schlosser,
Agrotechnology Laboratory of
Federal University of Santa Maria
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By Crébio José Ávila (Embrapa Western Agriculture); Charles Martins de Oliveira (Embrapa Cerrados); Suélen Cristina da Silva Moreira (Chapadão Foundation); Rodolfo Bianco (Paraná Institute for Rural Development); and Marco Antonio Tamai (Bahia State University)
