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The development of reference working cycles for agricultural tractors
Full text linkClimate change and the current energy crisis are creating new challenges to agriculture and new technological solutions must be developed to increase agricultural machinery efficiency. Researchers and machinery manufacturers identified electrified powertrains as a possible solution to meet this demand. The development of field-effective electrified powertrains is challenging mostly due to the wide variability of operating conditions of agricultural tractors. While the automotive industry adopted reference driving cycles for the design and evaluation of hybrid powertrains, the tractor industry has not been able to easily record external load in real-world conditions as it requires dedicated systems that cannot be used under prolonged field usages. This study aims to provide a methodology for estimating a reference working cycle from a multi-year dataset using technologies available in current commercial tractors. Data were collected on a tractor used for 3 years of agricultural work. Data were first clustered into work states, then, for each state, signal features from on-tractor sensors were used to extract key factors to compute the reference work state. With an optimisation solver and a hidden Markov model, the reference working cycle that synthesised the real-world tractor use was calculated. This cycle was compared with established cycles for non-road mobile machinery. The new reference cycle better represented real-world tractor usage as it also complied with low engine operations, which are frequent in farming and mostly associated with machine setup. The new reference working cycle permits a reliable estimation of fuel consumption of real-world farming
Tractive and soil compaction performances of an agricultural tractor fitted with rubber tracks
No full textThe objective of this study was to compare the tractive and the soil compaction performances of a conventional wheeled tractor with the fully tracked version of the same model.
The tested tractors were connected each other through a steel chain equipped with a load cell. The performances of the towing tractor were evaluated using the towed tractor as a brake, then the tractors were inverted in order to test both. The traction efficiency and the maximum draft force of the tractor were measured through the load cell and the tractor parameters acquired with a CAN logger. The soil compaction was evaluated through the analysis of soil bulk density and cone penetration test.
The results show a reduced soil compaction for the tracked tractor with respect to the wheeled version despite of the increase of the tractor mass due to the four rubber tracks weight. Furthermore, the tractor equipped with rubber tracks showed an improvement of the traction efficiency, especially on low grip surfaces
Influence of Ploughshare Wear on Plough Efficiency
No full textRegarding agricultural machines, one of the main durability requirements are the wear resistance of the soil engaging tools. Wear of soil engaging tools should be minimized, since it impairs the tool specifications and affects tractor performances, tillage quality and machine maintenance costs. The purpose of this work was to investigate the impact of a worn ploughshare on tractor performances. Wear leads to a geometrical change of the soil engaging tools and previous studies investigated the relationship between the tool cutting edge geometry and the developed drought by means of trials and Finite Elements Modelling. However, no study has reported the influence of worn ploughshares on the power requirements of soil engaging tools. The methodology adopted in this study consists in a comparison of the tractor performances between its configuration with a plough equipped with a worn ploughshare and the configuration with the same plough with a new ploughshare. The tractor speed was measured with a GPS receiver and important tractor parameters such as engine torque and fuel consumption were acquired through a CAN logger
Performance evaluation of electrically driven agricultural implements powered by an external generator
Full text linkIn the last decade, many studies have been conducted on tractor and agricultural machinery electrification. In particular, the electrification of power take-off (PTO)-powered implements could support many benefits, such as improved comfort and safety during implement connection, less noisiness, accurate control of the implement rotational speed, and fuel consumption reduction. However, commercially available tractors do not generate sufficient electric power to run electrified implements. A solution to this issue is powering eventual electrified implements with an external electric generator powered by the PTO and mounted with the front three-point linkage. This study aimed to evaluate the potential benefits of using this combination with respect to PTO powered implements. The types of implements analyzed in detail in this study were a sprayer and a mulcher. Field tests were performed acquiring performance, operational, and environmental parameters. Results show that on the electrified implements, the absence of the cardan shaft and hydraulic remotes shortened the time required for the hitching phase and reduced the in-work noisiness. Field tests demonstrated that the electrified implements permitted an improvement of the fuel consumption per hectare, up to 33.3% and 29.8% lower than their PTO-powered homologue for the sprayer and the mulcher, respectively
A Feasibility Study for Agriculture Tractors Electrification: Duty Cycles Simulation and Consumption Comparison
No full textInvestigating the efficiency of hybrid architectures for agricultural tractors using real-world farming data
Full text linkIn 2020, the European Commission (EC) approved the European Green Deal, which is an ambitious package of measures that aim to transform Europe into a climate-neutral area. Agricultural machinery in Europe produces around 70 million tons of CO2 emissions each year. Industry and researchers are currently investigating hybrid powertrains to significantly reduce CO2 emissions. This paper aims to investigate two hybrid powertrain architectures and report the benefits to farmers of such solutions using real-world data. Real-world data were collected using a Controller Area Network (CAN-BUS) data logger on a row-crop tractor with an engine power of 158 kW. Engine and transmission operating parameters were recorded for more than two years of field use. Data were first classified into tasks and then a series of inefficiency indices were defined. The operational inefficiency of each task type was then identified. Two hybrid powertrain architectures were evaluated using load point shifting principles. These were electric power take-off (ePTO) and plug-in P4 architecture. The hybrid architecture with the greatest benefits was the plug-in P4 powertrain, which achieved cost and CO2 savings of 7.2 % and 9.5 %, respectively. In the future, as the proportion of electricity from renewable sources increases, greater benefits could be achieved. On the other hand, the ePTO architecture permits to achieve a lower fuel saving, below than 2 %, but with a simpler technology
Challenges and State of the Art in the Agricultural Machinery Electrification
No full textThis chapter introduces the peculiarities of agricultural machinery and describes the main component of traditional machine configurations. After the description of the conventional powertrain of farming tractors and highlighting the most relevant challenges for electrification, it reports a description of the electrically driven internal combustion engine (ICE) auxiliaries. The most widely adopted structure in conventional powertrain for mechanical front‐wheel drive tractors. Besides the main powertrain, also ICE auxiliaries can be electrified in order to improve their consumption reducing parasitic losses. When electrified, the auxiliaries can be controlled more effectively operating, for example, with a speed controlled independently from the ICE speed. The two most demanding auxiliary loads are the HVAC (heating, ventilation and air‐conditioning) compressor and the cooling fan: both are responsible for about 10% and 30% of ICE‐rated power during onfield and idling operations, respectively
Preliminary Study On Traction Efficiency Of An Agricultural Tractor Equipped With An Extendable Ballast Holder
No full textPerformance Evaluation of a Computational Design Tool for Three-point Hitch Geometry Optimization
No full textFeasibility study of an idling-stop device on agricultural tractors
No full textIdling is a vehicle condition in which the engine is running at the minimum rotational speed without accomplishing any useful work besides the generation of energy required to keep it rotating. Agricultural tractors may idle from 10 to 43% of their service time and this inoperative time must be minimized since it is deleterious for the environment, public health, and fuel economy. Idling could be reduced by adopting anti-idling devices such as the idling-stop. Despite it is well adopted on cars, it is not present on any commercial tractor. Since the engine restart requires an energy surplus from the battery to run the starter motor, idling-stop devices are not efficient for very short idling stops. This study aims to quantify the potential advantage of using an idling stop device. Engine startup tests were carried out to evaluate the electrical energy and the fuel used for the engine startup. The electrical energy was measured through an electrical current and voltage sensors placed on the battery poles. Results confirm that with very short idling periods an idling-stop device is not energy efficient since the power provided by the battery to run the starter motor is higher than the energy saved during the engine shutdown. The minimum idling time that permits energy savings is about 4 seconds
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