- Location
- Hannover, Germany
Trends in tractors
Article by Roger J. Stirnimann, Dipl.-Ing. agr., Dipl.-Ing. Wirtsch., Executive MBA, University of Agricultural, Forestry and Food Sciences, Zollikofen
(DLG). For years, Agritechnica has been regarded as the world's most important platform for innovations in agricultural machinery, not least because of the Agritechnica Innovation Awards. In the run-up to the 2019 trade fair, numerous products have once again been presented by manufacturers and registered for this innovation competition. The following contribution aims to provide an overview of the most important innovations and the trends that can be determined from them.
Exhaust emission legislation remains a technology driver
Since January 2019, diesel engines in new tractors of more than 130kW have been required to adhere to Stage V exhaust emission limits; from January 2020, this will also be the case for the output class from 56-130kW. In terms of particulate emissions, the tighter weight limit values (g/kWh) have been joined by an additional limit for the number (total particles/kWh), making closed-loop particulate filter systems unavoidable. Some tractor manufacturers have completed the shift to exhaust emission Stage V engines on existing model series without a great deal of fuss in 2019, whereas others coupled this to the development and presentation of new models.
Common rail fuel injection, four-valve technology, turbochargers, charge air cooling, viscous fans and electronic engine management remain the engine technology mainstays for reconciling the requirements of power output, consumption and emissions. Familiar technologies are also being implemented in terms of exhaust emission technologies. The diesel oxidation catalytic converter (DOC), diesel particulate filter (DPF) and selective catalytic reduction (SCR) exhaust gas aftertreatment systems are always fitted in exhaust emission Stage V engines on agricultural tractors; as regards exhaust gas recirculation (EGR), differences are now only to be found in the form of internal engine technology for the avoidance of nitrogen oxide formation. On the whole, a trend towards reduced recirculation rates, or even complete omission, is now emerging. Besides CNH, as a long-standing advocate of SCR-only, Fendt, for example, is now also doing away with EGR in its new Vario 900 large tractor model series.
The DOC, DPF and SCR exhaust gas aftertreatment systems are increasingly being contained in compact single modules and positioned outside of the engine area. A typical example of this is the all-in-one solution from Massey Ferguson for the 6700S and 7700S model series. CNH is using new SCRoF systems in which the DPF has an SCR coating and therefore partly undertakes nitrogen oxide reduction. The complete exhaust gas aftertreatment system, consisting of DOC, a coated DPF and smaller SCR thus takes up barely more installation space than the previous Stage IV exhaust emission systems with DOC/SCR. The medium-size class model series with four- and six-cylinder engines from all three CNH Group brands have now also been joined by the re-engineered Case IH Magnum AFS Connect large tractor model series with SCRoF technology (six-cylinders, 8.7 litre engines).
A paradigm shift is taking place in the topic of power boosts. Previously falling squarely in the non-boost camp, Fendt is now implementing a sensor-controlled solution called “Fendt Dynamic Performance” in its new Vario 314, thanks to which the same basic output is always available for actual work. This boost power is activated variably depending on the power required by ancillary consumers such as the fan, alternator, air conditioning system and air compressor. As a proponent of abundant power boost, Case IH is shifting in the opposite direction and ensuring that the rated and maximum power (397hp and 435hp) are available under all operating conditions in its new Magnum 400 model.
Numerous tractor prototypes with gas engines have been presented in the past, but none of them ever made it to the market. New Holland is now the first manufacturer to present a tractor with a gaseous fuel drive that is fit for series production among the brand’s T6 series. Additional CNG tanks are planned to extend the operating time; these are carried in a special frame on the front hydraulics and can be connected to the main tanks on the tractor by means of quick couplings. In terms of the drive, the manufacturer is implementing the 'Natural Power' unit with six cylinders and a displacement of 6.0 litres from its sibling company FPT. This operates according to the spark ignition principle, and is therefore powered exclusively with gas.
First gearbox with electro-mechanical power split
Thanks to their high full load efficiencies and longevity, powershift gearboxes continue to hold their ground, particularly on farms with high percentages of heavy pulling work. New or improved partial and full powershift gearboxes have therefore been presented time and again in the recent past. Case IH is now also extending the familiar 18/4 and 19/4 versions for the aforementioned Magnum 400 to offer a 21/5 full powershift gearbox with which the vehicle can be driven at both 40 and 50 km/hr at a reduced engine speed. With the “Valtra Powershift Revolution”, meanwhile, the Agco Group company is now offering the joystick operating logic familiar from the stepless Direct gearbox for the Versu partial powershift gearbox.
Stepless gearboxes with hydrostatic/mechanical power split have now been in use for more than 20 years in agriculture. So far, an additional generator had to be fitted for electric drives with higher power requirements on the tractor, trailer and implement. John Deere is now taking a new approach with the eAutoPower gearbox for the new 8R large tractors by completely forgoing the hydraulic unit (pump/motor) and instead implementing two electric motors. These not only take over the function of the variable actuator in the power split gearbox structure, but additionally provide electrical power of up to 100kW for external consumption. This can be used, for instance, to drive electric driving axles of large trailers or semi-mounted ploughs, thus leading to increased traction and reduced slip. Thanks to this tractor/implement electrification, large liquid manure tankers with slurry injection equipment can be operated with smaller tractors, for instance, which can lead to higher payloads in the event of gross weight limitations on the road. On the tractor side, this electromechanical power split should result in improved gearbox efficiencies and lower running costs. When taking off electrical power for electric drives outside of the gearbox, the reactive power flows that occur at certain operating points in power split structures can additionally be “tapped”, thus further improving the overall efficiency.
Fully electric concepts with batteries are still being taken into consideration for smaller tractors. At Agritechnica, the Swiss company Rigitrac will be exhibiting a further developed version of the SKE 50 Electric prototype with 50kW, which was presented for the first time at the end of 2018. The lithium-ion battery has a capacity of 80kWh and is mounted between the axles beneath the cab. Up to five electric motors can be supplied by the 400V electrical system: one each for the front and rear axles as well as for the rear and front power take-off, and one to drive the hydraulics pump.
Track drives continue to gain ground on larger tractors
For high traction and low soil pressures, large standard tractors are increasingly being equipped with semi-track drives. Specialised manufacturers have been offering retrofit solutions for front and rear axles for some time now. Factory-fitted semi-track drives for the rear axles of their own large tractors have also been presented by CNH and Claas in recent years. The front axles of wheeled tractors are not usually designed for such drives, which is why problems may arise if they are retrofitted. For its Magnum model series, Case IH is offering new steering assistance through automatic brake pulses at the rear wheels for both the semi-caterpillar and the wheeled models.
Improved comfort when working with large balers
No less than two manufacturers, John Deere and New Holland, are presenting systems to reduce the shocks caused by large balers in tractor cabs. These are very unpleasant for the driver and can lead to health problems. For its own large baling machines in combination with 7R model series tractors, John Deere is offering intelligent vibration damping in which piston shocks are compensated by briefly changing the speed in the stepless gearbox. Various sensor signals are taken into consideration for this; no additional hardware is required. New Holland is taking a slightly different approach and is equipping its T7 tractor model series with a baling mode that also functions with large baling machines from other manufacturers. Here, the piston shocks are intercepted thanks to a modified front axle suspension set-up and a steeper engine cut-off curve setting.
Digitisation in practice
Digitisation has definitively arrived in tractors. Several manufacturers are presenting telemetry systems, albeit with different focuses. With Valtra Connect, this involves efficient fleet management, TIM remote diagnosis from Kubota is focused on the simplified, brand-independent fault analysis of tractor/implement combinations and TracLink Smart from Lindner is concerned with automatic implement recognition using SmartTags and web-based setting recommendations.
With FendtONE, Fendt is presenting a new operating philosophy that is intended to eliminate the boundaries between the on-board world on the tractor and the off-board world in the office. The completely redesigned cab, which will initially be available for the 700 series and the top 300 series model, the 314, will be equipped with a total of four monitors for which the contents of the display areas can be freely selected. For example, the satellite guidance display can be shown on the electronic dashboard equally as well as on the ceiling monitor, which can be pushed partially or completely into the ceiling. In addition, individual tractor functions can be assigned to almost all of the buttons in the new control armrest; a dynamic colour concept quickly indicates the current allocation.
