(DLG). At Agritechnica 2023, the manufacturers of threshing crop harvesting technologies will be presenting innovations in the areas of threshing and separating as well as for ensuring performance stability and work quality. The power density is increasing further with limited construction volume. When harvesting on the flat and on lateral slopes, performance stability and work quality are being further increased through control technologies and semi-automated calibration technologies.
Drive technologies increasingly efficient and compact
Combine harvesters’ very expensive drive trains have to be extremely efficient and compact. Wherever possible, the manufacturers therefore use mechanical belt drives for assemblies with high and medium power consumption in order to increase overall efficiency and minimise diesel consumption. Threshing drums as well as threshing and separating rotors are driven either with conventional, highly developed variator technology or with power-split gearboxes. While hydraulic rotor drives such as those used in combine harvesters from South American manufacturers offer the advantage of simple reversing in the event of a blockage, they prove unsuitable due to their low efficiencies, particularly when harvesting high volumes of straw.
In order to reduce the number of belt drives between the engine and the intake duct, propeller shafts are used to transfer the rotary power to the harvesting header in some concepts. However, the belt drives for the feed, accelerator and threshing drums are then still located between the outer frame and the running gear.
There are no drive trains whatsoever between the running gear and the outer chassis on the new twin axial rotor combine harvester from New Holland. The rotary power for the harvesting headers is transferred using a propeller shaft above the running gear on the right-hand side of the machine. The feed drum for the two rotors is driven mechanically via the left axial threshing and separating rotor as a counter shaft. This design creates space between the chassis and the running gear, enabling the chassis to be made wider while the transport width has remained the same. With a channel width of 1.56 metres in the successor to the familiar CR model, New Holland has consequently widened the chassis to more than the previous maximum values, and therefore now manufactures the combine harvester with the largest threshing channel width, i.e. with the corresponding performance potential.
The core element of the drive trains in the new CR combine harvester is the centrally located split-power gearbox in combination with the engine, which is now mounted longitudinally and in a slanted position corresponding to the rotors’ angle of inclination. This gearbox even enables software-controlled unblocking of the rotors by first loosening the blockages through alternate back and forth rotation and then sending them along the usual path taken by the straw. This automated unblocking technology is a sensible evolution compared to systems with manually operated reversing technology.
Case is presenting a sensor for detecting the condition of bearings. Developed in cooperation with Flanders Make, the system operates autonomously once it has been attached to the bearing. Via WiFi and an app, the vibration data of a bearing are used to calculate the remaining service life and are transmitted to the user’s mobile phone.
Continuing trend towards belt cutting systems and scanner technologies
Belt cutting systems are acquiring increasing market shares both because they can be equipped with flexible cutter bars and because they adapt to uneven ground with a segmented frame transverse to the direction of travel. This is particularly advantageous with large working widths in excess of 10 metres because the pick-up losses on cropped terrain and in the case of crops with ears close to the ground are reduced. Cutter bars with a working width of up to 15.2 metres are being presented, e.g. by MacDon.
No ideal technical solution has been found as yet for preventing the essentially higher but usually still tolerable pick-up losses of belt cutting systems when harvesting rape. The reason being that, on the one hand, the cross conveyor belts rub against the silique even before the plant is cut down, leading to an increased accumulation of rape in the area of the cutter bar. On the other hand, the risk of trickle losses due to leaks, particularly on transition from the cross conveyor belts to the longitudinal conveyor belt, exists in all makes.
Following John Deere’s presentation of the first forward-looking combine harvester at Agritechnica 2019, Case will now also be presenting a system that scans the threshing crop stock ahead of the cutter bar. Radar sensors that scan the stock and the ground in front of the cutter bar are mounted on supports that protrude over the reels. This means that even a threshing crop lying in different directions can be detected over specific partial widths. The patented system permits harvesting closer to the performance limit of the combine harvester, because it foresightedly regulates the vehicle’s speed. Case emphasises the system’s operating reliability due to its insensitivity to dust. It additionally helps to guide the cutter bar because it is able to detect areas of uneven ground. The DLG Innovations Committee has awarded a silver medal to this approach, which is new compared to previous techniques.
Trends in threshing and cutting
The trend towards higher power densities with limited construction volume is continuing. New combine harvesters with increased threshing performance in the top output categories were presented by almost all manufacturers at previous Agritechnica exhibitions. It is always astonishing which constructions engineers develop to increase the power density of combine harvesters although the limits are increasingly being encountered in terms of dimensions and weight.
With respect to transport by road, the objective is always to keep the overall width of the combine harvesters within the 3.5-metre limit when using half-tracks or 680 to 710 mm wide front tyres. On the large models, however, these front tyres involve excessive compromises in terms of soil protection, making half-tracks a must for implementing good professional practice. As the axle loads, particularly those of the rear axles, become too high for road transport, the designers are increasingly using methods for reducing the weight of the machines while maintaining consistent stability. Relatively wide differences can be seen in this case between the various manufacturers’ designs.
In their top models, the three major manufacturers AGCO, CNH and John Deere are each relying on axial threshing and separating rotors according to the example set by New Holland back in 1974 using twin rotor technology. Claas is building tangential axial rotor technology, meaning that threshing is carried out with a threshing drum and the grain is then separated using one or two axial separating rotors. Following John Deere’s presentation at Agritechnica 2019 of the X9, the combine harvester with what is currently the widest chassis and which has since been launched onto the market, New Holland is now also presenting the successor model of its familiar CR combine harvester. The above described design of the drives with a widened chassis enables the installation of rotors with more than the previously maximum diameter of 24 inches and an increased length.
Cleaning is becoming a bottleneck in rotary combine harvesters
Particularly under dry harvesting conditions, rotary combine harvesters cut off more short straw than walker combine harvesters, something that places a strain on cleaning. Cleaning in these combine harvesters therefore limits performance far more than in walker combine harvesters. Naturally, the cleaning capacity has to match the large rotors. Here, New Holland is relying on a new development consisting of two cleaning systems that are virtually connected in series. Consequently, the threshed crop is conveyed into the grain elevator with two grain augers, one above the base of the elevator and one in the base, as usual. With these features, New Holland’s new CR can be classified as a combine harvester with a longitudinal flow principle and maximum performance potential.
The ingenious aspect of the cleaning system in New Holland’s new CR combine harvester is its departure from the familiar cleaning slope compensation function. In its place, wind pressure sensors now measure the distribution of the wind and therefore the harvested crop on the upper sieve. In the event of uneven distribution, the mix of grain/non-grain constituents is shaken to the bare area. This technology not only ensures consistent crop distribution on the upper sieves on lateral slopes, but also on the flat. The reason for this is that, on axial rotor combine harvesters, the lateral distribution of the harvested crop on the preparation floor and the upper sieve, and therefore the load of the cleaning system, changes depending on the throughput and condition of the harvested crop. New Holland has solved this problem for the first time with this control technology.
The new slope compensation function for John Deere’s cleaning system is called Active Slope Adjustment. A cross conveyor belt is located between the preparation floor or the feed augers and the pre-sieve of the ventilated drop stage. It conveys the mix of grain/non-grain constituents upslope and therefore reduces grain losses on a lateral slope. The comparatively simple system can also even out the cleaning system’s load by moving back and forth, thus increasing its performance.
In addition to these developments, the familiar slope compensation technologies for cleaning also remain on the market. These include the familiar 3D and 4D control technologies from Claas and the shaking (like 3D) and horizontal positioning technologies from CNH. On the Ideal combine harvester, AGCO offers special technology for guidance into the cleaning system segments rather than control technology. All manufacturers are marketing running gear slope compensation technologies for wheeled machines; these are not available for machines fitted with half-tracks, because they are not constantly operational on lateral slopes. The trend towards stabilising threshing performance even under difficult operating conditions on hilly terrain is virtually as old as the combine harvester itself and still remains unbroken.
Trends in information and control technologies
Depending on the harvesting and operating conditions and its settings, each combine harvester generates what is called a loss/throughput characteristic. This means that, according to diverse statistical regression functions, grain losses increase along with the throughput, i.e. when the vehicle is driven faster, or when the harvesting conditions become less favourable, e.g. due to higher straw yields or moistures. Combine harvesters are becoming more expensive and powerful meaning that, on the one hand, the costs are too high if the operating rate is too low. On the other hand, however, the costs caused by excessively high grain losses – these refer not only to lost revenues, but also to costs for soil tillage, sowing and care – must not lead to an agronomic imbalance. Consequently, knowledge of the grain loss level is becoming increasingly important for calibrating the grain loss monitor, whose function has essentially remained unchanged for a number of decades.
Claas is presenting a semi-automated calibration system for the grain loss monitor. The dimensions of the lost husk first have to be specified. Which husk is used for measurement is therefore completely irrelevant. Depending on operating status – windrow placement or chopper operation – and the machine’s equipment or the distribution system, the dialogue-based system actually issues recommendations on where the lost husks are to be placed for a precise result.
The results of the lost husk check are compared with the combine harvester’s CAN data. Depending on the desired loss level, CEMOS DIALOG calculates the sensitivity to be set for the grain loss monitor. In the event of a change in the specified loss level, e.g. an increase in order to harvest the field before it rains again, the respective sensitivity of the loss monitor is calculated and the new setting value is recommended. In contrast to familiar systems, this system enables rapid machine- and situation-specific calibration of the loss sensor system for the first time. This therefore makes harvesting at the specified grain loss limit more precise and increases efficiency and cost effectiveness.
Known under the name BushelPlus, Geiger Agri Solutions from Canada is presenting a new loss sensor that registers particle sizes and is intended to measure grain losses including fragments using AI. The sensor is installed downstream of the cleaning system. The related AI indicates the grain losses. The system enables the loss level to be specified so that the combine harvester can be operated at full capacity up to this loss limit. This technology only registers the cleaning losses, not the losses of walkers or rotors. Testing is still needed to determine whether it also functions under European conditions with high straw yields and consequently performance-limiting grain losses from the residual grain separating technology. The approach is at any rate very creative, as the corn loss sensor systems of combine harvesters have basically remained unchanged over the past 40 years.
NIRS sensors are increasingly being offered for combine harvesters. These are used to measure the constituents of the threshing crops, such as the protein and oil content and the crop’s moisture. Next Instruments from Canada is presenting a system that also uses the combine harvester’s CAN data. The results are used for logistics and to document the constituents of the harvested areas. Nutrient yield maps can be created and application maps for N fertilisation can be prepared based on the protein content of the threshing crops. Whether this technology, which already exists in Canada, can be used profitably under European agricultural conditions and legal regulations is still debatable at present.
The digital coupling system evolved by John Deere between the combine harvester and the unloading vehicle is called Combine AutoUnload. A camera monitors the threshing crop material cone in the transport vehicle in order to ensure uniform loading without overloading losses. The system operates similarly to the technology available on forage harvesters for automating transport vehicle loading. It is an evolution of the familiar MachineSync system. As the bunker capacities of large combine harvesters are already as much as 20 cubic metres and their unloading capacities are around 10 cubic metres per minute, the use of such unloading aids is sensible.
With increasing combine harvester and header trailer transport lengths, cramped conditions in road traffic result in multiple blind spots that are not visible to the drivers despite large rear-view mirrors, particularly when turning off and driving into tight entrances. AGCO is therefore presenting the Fendt VisionPlus camera system. On cornering, the cameras remain trained on the areas alongside the combine harvester and the header trailer, thereby enabling possible collisions with obstacles to be recognised early on.
Trends in straw and chaff management
Foreseeably, the working widths of large combine harvesters will be the already often used 14 metres up to 16 meters and more in the future. The distribution of chopped straw and the chaff with the familiar distribution technologies is therefore posing an increasing challenge, particularly on lateral slopes and in a side wind. In addition, the chopping and distribution technology of combine harvesters is also marked by its high energy input.
On its new axial rotor combine harvester, New Holland is regulating the chopping length using camera technology. The nominal cutting length is specified and compared against the image of the actual cutting length. If the nominal and actual cutting length do not match, the system adjusts the shear bar to cut shorter or longer. In combination with the counter-rotating cutting rotor, this technology, which adapts to the harvesting conditions, reduces drive power consumption on the whole. With this sensor system, which also measures directly, and the radar technology for lateral distribution that won an award at Agritechnica 2022, New Holland has therefore taken a further step towards automation.
On the whole, the new twin axial rotor combine harvester from New Holland offers a high number of further developed technologies. In particular, its innovative drive train and its new cleaning system offer further scope for increasing its technical threshing capacity. The machine is additionally equipped with numerous new automation and control technologies for increasing operating reliability and work quality. The new twin rotor combine harvester from New Holland has therefore been evaluated as a milestone in the evolution of the combine harvester by the DLG Innovations Committee, for which it has been awarded the Agritechnica gold medal.
The trend towards technologies that cut the straw uniformly and accordingly distribute it laterally over the entire working width with the lowest possible energy input continues to remain in place, because high work quality in the area of chopping and distribution is the basis for precise crop production and is consequently desired by agronomists. The working width as of which the familiar radial distribution technologies encounter their limits and additional cross conveyors have to be used remains to be seen. NEXAT has a simple solution to the problem: comparable to New Holland’s earlier TF system, the material flow that is divided by the threshing system exits the combine harvester on both sides. This halves the throw and therefore increases lateral distribution accuracy.
Trends surrounding combine harvesters
As the performance of combine harvesters increases, setting optimisation and sensor system adjustment are playing an increasingly important role, because incorrect settings on large machines lead to financial losses that are higher in relation to those on small machines. The manufacturers are therefore continuing to evolve their setting and other control technologies.
Experience from the past few years has shown that a combine harvester must be designed so that it can be adapted to diverse harvesting conditions. However, a combine harvester can only exploit this adaptability in the form of increased performance and work quality if the effects of the various technologies are known or these technologies, such as a pivoting threshing concave bar or threshing concave flap as used by Claas, for instance, are integrated into the control technology for optimising settings. If no control technology is ordered, the users should be familiar with the ways in which the various additional tools work. This also includes John Deere’s booster bar, which can also be operated using a spanner, for instance.
The accessibility and exchangeability of threshing concaves on tangential combine harvesters have been improved in recent years. On axial combine harvesters, they are pretty much ideal and enable the threshing and separating concaves to be exchanged quickly depending on harvesting conditions. However, these basic stop settings are not changed during a harvesting day due to time reasons. In this respect, tools that can be switched on or off, ideally in a non-stop procedure, are the better, albeit more expensive, alternative.
Harvesting, in the form of both dry and wet harvesting, once again proved to be a major challenge in 2023. The threshing crops, which had matured early on under stressful drought conditions, proved difficult to de-awn and de-husk. After the rain period, this was compounded by brittle, incompletely threshed rachises, which were separated off at the concave inlet and entered the cleaning system. These were then threshed again as returns or fell into the field as losses. Combine harvesters with numerous adjustment options – if they are used – or automatic adjustment are outstanding under such changeable harvesting conditions. Harvesting once again confirmed the long-term trend that combine harvester operators are increasingly becoming the performance-limiting factor if technical aids are not used, known or available.
Summary
The manufacturers of threshing crop harvesting technologies will be presenting numerous innovations in the area of threshing crop harvesting at Agritechnica 2023. The trend towards harvesting headers that can be adapted to diverse conditions is continuing. While the belt cutting systems marketed by the international manufacturers are increasingly being tailored to the European market, harvesting rape, particularly in crops lying in different directions within the working width, continues to pose a material flow problem.
The trend towards increased combine harvester power density and automation is continuing. New Holland is advancing into a new performance dimension in twin axial rotor combine harvesters using the longitudinal flow principle. The width of the threshing channel has been increased on the basis of a completely new drive concept. Added to this is an innovative cleaning system, because the forms familiar from rotary combine harvesters are increasingly becoming a performance-limiting factor. New Holland is to be presented with an Agritechnica gold medal for the machine as a whole.
Numerous innovations surrounding the combine harvester will be on show at Agritechnica 2023. Case is to be awarded a silver medal for the new radar technology in front of the cutter bar for the foresighted combine harvester. A very high number of new technologies will be presented. from semi-automated calibration procedures for the loss monitor and data collection technologies for threshing crop constituents, which can be used for diverse purposes, up to and including further control technologies for slope compensation and straw/chaff management . The priority remains to ensure that these technologies are affordable and economically viable. Ultimately, this will be determined by the customers, the farmers and contractors who would like to use these technologies profitably.
