Vegetable-based Oil as UTTO Fluid for Agricultural Tractors Application

Abstract

HighlightsLubricants are commonly used in agricultural activities involving machines.To reduce lubricants impact on the environment, a process has been started for replacing them with products obtained from vegetable oils.Tests have been carried out to explore the possibility of introducing vegetable-based UTTO in tractors.Results encourage to deepen the behavior of vegetable-based oils and develop specific test bench and methods.Abstract. To reduce the impact of mineral and synthesis lubricants on the environment, a process has been started for replacing them with lubricants and hydraulic fluids obtained from high-oleic vegetable oils, with good tribological properties, high biodegradability, and low toxicity. Test have been carried out at Research Center for Engineering and Agro-Food Processing of Monterotondo, Rome, Italy, with the aim of comparing the performances provided by a standard agricultural tractor supplied with conventional Universal Tractor Transmission Oil (UTTO) fluid and with a vegetable-based oil in their transmission-hydraulic system group. The research aimed at assessing differences, if any, in tractor’s performances attributable to the fluids in comparison. For a better comparison, the tests were carried out under controlled conditions, connecting the tractor, at first to a dynamometric brake used in engine and transmission tests, then to a test rig for hydraulic lifts. The results, although non generalizable, were encouraging, indicating that the tractor’s performances with the two fluids, after 30 h work cycles, were similar both for transmission and hydraulic lift. On the other hand, the reduction observed in the viscosity of the biofluid requires the deepening of the aspects related to its durability. The results also allowed to focus some basic aspects of the evaluation of biofluids and to identify some methodological approaches mainly based on the comparation of fluids performance during repeatable work cycles and on the assessment of how their physical properties evolve overtime. Keywords: Biolubricant, Engine performance, High-oleic sunflower oil, Hydraulic lift, Lifting force, Power transmission.

Test Rig and Method for Comparative Evaluation of Conventional and Bio-Based Hydraulic Fluids and Lubricants for Agricultural Transmissions

“…Before the introduction of bio-based fluids in real-world conditions, these encouraging results have to be confirmed in tests representative of real working conditions, where their performance must be at least equivalent to those of the conventional fluids they have to replace. In this respect, a first series of tests on a tractor in service showed good performance of a bio-based UTTO fluid compared to a conventional one [28]. However, in spite of its relative short duration, the test also evidenced the initial process of fluid degradation.…”

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“…Furthermore, it has been demonstrated that vegetable oils have high flash points, a high viscosity index, and low volatility [9]. The biggest drawback of using vegetable oil is its low thermal and oxidative stability [10]. The use of modifiers such as friction modifiers (FMs) has been shown to greatly reduce friction.…”

Bench Testing of Sensors Utilized for In-Line Monitoring of Lubricants and Hydraulic Fluids Properties

“…The reported data of work and energy have been calculated basing on the above-mentioned test interval of 150 h as a reference. Oil volume in the multiplier dm 3 2.6 Oil temperature 3 • C 60 Oil temperature 4 • C ≈87 Flowrate 5 dm 3 min −1 0.2 Electric engine speed min −1 660 Dynamometric brake shaft speed min −1 1670 Torque at dynamometric brake 6 daNm 10.4 Mechanical power 6 kW 18.2 1 In the reservoir/before high-pressure pump. 2 After the lamination at 40 MPa.…”

“…At first, the suitability of biobased lubricants is usually assessed in proper work cycles based on special test benches, by monitoring the fluid properties through periodic samplings and laboratory analyses, capable of providing accurate information on the oil status [4,5]. The next evaluation step is based on the use of real machines (e.g., tractors) employed in normal work (e.g., farming operations), always monitoring the fluid status by sample analysis [6]. Such a method often requires the intervention of specialized (often external) laboratories and its limits consist of the costs, the time for analyses, and the time interval between samplings during which the fluid-machine system is exposed to undetectable variations or damage.…”