Investigating the Performance Parameters of ITM4120 and ITM399 Tractors Produced by Iran Tractor Manufacturing Company

Considering the rapid advancement of technology worldwide and the emergence of new innovations in agricultural machinery and precision agriculture—especially in recent years—along with the growing emphasis on energy savings and the rising cost of fuel globally, and particularly in Iran, improving the quality of tractors has become essential (Lanças et al., 2024). As the most important piece of agricultural machinery, tractors play a critical role in modern farming, and enhancing their efficiency and performance is vital for sustainable agricultural development (de Melo et al., 2022; Hoy & Kocher, 2020; Zhu et al., 2022).

The purpose of this research is to investigate the effects of installing a turbocharger system on engine fuel consumption, power, slip, and traction parameters in a turbocharged ITM4120 tractor compared to a conventional ITM399 tractor without a turbocharger.

Materials and Methods
The tests were conducted on the second-grade concrete runway at the Tabriz Tractor Manufacturing Company for various tractor evaluations, including traction tests, in accordance with the guidelines provided by the Standards Organization. The air temperature was 23 ± 7 ℃, and the air pressure was approximately 96.6 kPa. The weather conditions ranged from partly cloudy to clear, as per OECD standards. To conduct the tests, ITM4120 and ITM399 tractors were used (Figure 1). To measure the traction force between the two tractors, a 5-ton load cell model 5BBP , manufactured by Bongshin Korea , was used. This device has a measurement accuracy of 0.1 kg . A Sigma 5 dynamometer made in England was used to measure PTO power. This dynamometer has a maximum operating speed of 100 km/h, a maximum coupling weight of 100 kg, and a maximum axle weight of 1300 kg, with a power measurement accuracy of 0.1 hp and torque of 0.1 rpm. Additionally, a VDO-EDM1404 fuel gauge (manufactured in Germany ) with a measurement accuracy of ±1% was employed to measure fuel consumption. A stopwatch with millisecond accuracy was also used for precise timing during the tests. Furthermore, a thermometer was utilized to measure the ambient air temperature and ensure it remained within the OECD standard range , with an accuracy of ±0.1 degrees Celsius . (Figure 2). The specifications of the ITM 399 and ITM 4120 tractors are shown in Table 1.

Preparation of test equipment and devices
According to the recommendations of the standards organization and the manufacturer of the tractor and tires used, prior to the commencement of the tests, eight suitcase-shaped weights, each weighing 34 kg, were permanently installed at the front of the tractor. Additionally, two cast-iron weights, each weighing 50 kg, were permanently installed on each of the rear wheels of the tractors. ballast, in this study refers to being the tires are filled with water or left empty. Tire ballast was applied to each tractor with an air pressure ranging from 0.8 to 1 bar. To increase tractive force while maintaining the center of gravity and ensuring appropriate weight distribution for four-wheel-drive tractors, the tires were filled with water, as outlined in Table 2.
The traction test was conducted on four-wheel-drive tractors in this project. The test was performed in accordance with OECD standards, in light and heavy gears, as well as tortoise and rabbit modes, at varying engine speeds. The tests were repeated three times on the concrete runway of the Tractor Manufacturing Company. During these tests, parameters such as slip percentage, tractive force, power, fuel consumption, specific fuel consumption, and specific power were measured and calculated. These values were also computed with ballast applied at maximum power across different gears (gears one, two, and three in both rabbit and turtle modes, as well as in two modes—light and heavy—using a 12-gear synchronized lever). The tests were carried out under varying loads, corresponding to 25%, 50%, 75%, 85%, and 100% of the pulling force at maximum power, as well as 50% of the pulling force in the first lighter gear, where the engine speed drops in both tractors. The data values were recorded in accordance with the standard table for all three repetitions for each tractor. Subsequently, the necessary analyses were performed on the collected data.

Drawbar tensile test
To conduct the tests, each of the tractors under examination (the turbocharged ITM4120 and the non-turbocharged ITM399) was hitched to the ITM1500 tractor, which was equipped with a throttle to generate drawbar pull as the load tractor. The tested tractors pulled the load tractor in different gears, while a load cell placed between the two tractors recorded the traction force. This data was logged by a data logger installed inside the cabin (Figure 3). These tests were performed for both tractors in three experimental stages. The wheel slip of the driving wheels of the test tractor, forward speed, and data from the load cell and fuel gauge were recorded in two conditions: with and without load, and with and without ballast.

Results and Discussion
In the results, the charts and tables related to the statistical analysis of data from the ITM4120 turbocharged tractor and the ITM399 non-turbocharged tractor's drawbar pull tests with ballast are presented. The effects of the turbocharger system on parameters such as drawbar pull force, fuel consumption, specific fuel consumption, and tractor power have been included. The statistical design employed utilized two-way ANOVA in the SAS software due to the presence of two independent variables (gear effect and tractor type).