Mathematical Model of Diesel Engine Characteristics for Determining the Performance of Traction Dynamics of Wheel-Type Tractor

Abstract

Wheel-type tractors carry out a range of processing operations, with the exception of early spring work, when caterpillar tractors are used to reduce the compaction effect on the soil. Therefore, to plan the costs and reserves associated with fuel consumption, it is necessary to have an estimate of the fuel economy of the tractor in basic agricultural operations. An objective assessment of fuel consumption requires a mathematical model that describes the fuel characteristics of the engine, taking into account the speed and load torque in a wide range of variation. Verification of the model is possible only with experimental data. Since the efficiency and fuel economy of a tractor depends not only on engine performance, but also on the perfection of the transmission, the running system and the rational choice of speed, it is necessary to take into account the time-varying nature of the tractor’s traction load. The complex of agricultural operations can be divided into characteristic cycles of load change over time. This principle is the basis of PowerMix test cycles, which are conducted on a concrete track to ensure repeatability of the experiment. The use of the variable load on the tractor in the PowerMix tests is positive, but in actual field tests the results may differ due to the instability of the soil properties. On the other hand, PowerMix field cycles can be taken as standard test loads in the simulation of tractor traction tests on the ground

Determination of Rational Operating Modes of Operation of Tractor Agricultural Tires

“…When determining the maximum ground pressure, a model of the universal tire characteristic was applied (9). The calculation results (1)- (11) are shown on the example of 800/70 R38 tire (Fig. 1).…”

“…The prospect for further research is the implementation of the proposed theoretical results in the simulation of traction dynamic tests, for example, PowerMix field cycles [11]. In addition, the issue of rational equipping the tractor with twin tires cannot be ignored.…”

Determining conditions for providing maximum traction efficiency of tractor as part of a soil tillage unit

“…Thus, in the assembly with various mobile units, the maximum is provided on double wheels for the second group of operations at m sp = 65.0 kg/kW (m o = 14370 kg) and the maximum traction efficiency η Tmax = 0.719. The ability to take into account the power flows for the John Deere 8R series tractor through the front and rear PTO using equation (9), allows one to estimate the efficiency of the combined units, as shown in Fig. 4.…”

“…However, this approach does not take into account additional loading of the tractor with the mass of the aggregated agricultural machine, especially when the mass changes during the technological operation. The variable load that causes such an additional load can be simulated using PowerMix tests, as reported in [9], which, together with the optimal selection of the mode, will increase the traction efficiency of the tractor.…”

“…∏ is the product of the efficiency of serially connected links of parallel consumers. Using formula (9), the efficiency of combined agricultural units is estimated in Fig. 4.…”