• Journal of Biosystems Engineering
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• 제31권1호
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• pp.1-8
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• 2006

This study was conducted to identify the characteristics of PTO rattle noise of a direct engine-PTO driveline for agricultural tractors. In order to reduce production costs of agricultural tractors, a direct engine-PTO driveline was recently introduced to the tractors produced in Korea. This simplified drive line reduced a number of gears and counter shafts in previous one. However, it caused a severe rattle noise under an idle condition, which was perceived as intolerable by many tractor operators. PTO rattle noise was measured at two locations: one 3 em apart radially from the centerline of the PTO shaft and another 100 em apart backward from the PTO end and 160 em high from the ground. Characteristics of the rattle was analyzed using the data measured near the PTO shaft. It was found that the period of rattle noise was same as the explosion stroke of engine and its peak level was about 123 dB (A) with PTO engaged at an idle engine speed of 880 rpm. As the engine speed increased, the rattle noise decreased. The frequency band of the rattle was 0.5-2.0 kHz and the frequency of peak sound pressure was 1.4 kHz. When compared the rattle noise between the locally produced and imported tractors of the same type of PTO driveline, the former generated louder rattle noise than the imported one by 7 dB (A). It was suggested that the rattle noise of local tractors must be reduced at least by 7 dB (A) to meet the international level.

• Journal of Advanced Marine Engineering and Technology
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• 제25권6호
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• pp.1203-1210
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• 2001

This study was carried out to develop an engine for off-road vehicles especially for farm tractors using the liquefied petroleum gas (LPG) which is known as a source of energy having good potential of substitute fuel for diesel engine because of its economical advantage and low pollutant materials after combustion. The study was focused on develop an engine of high in specific power output, low in specific fuel consumption and emission of pollutants. A series of teat was dope on the engine - various laboratory tests to analyze performance of the engine and actual field tests with the engine installed on a farm tractor as a power source.

• Journal of Biosystems Engineering
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• 제35권1호
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• pp.1-9
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• 2010

A mathematical model was developed to predict the fuel consumption rate consumed by agricultural tractors under arbitrary loaded conditions. The model utilizes the measured data on the fuel consumptions at the full load and at the rated engine speed with partial loads, which can easily be obtained from the official OECD tractor test reports. It was found from the analysis of the measured fuel consumption data that the fuel consumptions at two different speeds does not change with power. The model was developed based on this fact and validated with the measured data of the 159 tractor test reports. The fuel consumptions predicted by the model were compared with those measured under the partially loaded conditions specified in the official OECD tractor test code II. The percent errors of the predicted fuel consumptions were in a range from 0.36 to 2.86% which assured that the developed fuel consumption model can be used practically to predict the fuel consumptions at any speed and power combinations. It was also shown that the developed model predicts the fuel consumption rate better than the Grisso's model.

• Journal of Biosystems Engineering
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• 제3권2호
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• pp.126-132
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• 1978

This study was carried out through the survey questionaries in order to get the information for proper operating technique of the two-wheel tractors which are widely used in the farm, and investigated various accidents which occurred during the operation of two-wheel tractors for farm works in 7 Provinces of Korea. The summarized results are as follows ; 1. Annual accident frequency of the two-wheel tractor was 2.07 times, and the average rate of accident was 0.72 times per hour. Its value was the largest in the pre-operations , and the smallest in the threshing operation. 2. The accident distribution according to each month was nearly propertional to the operating hours of the two-wheel tractor. More than 60 % of total accident was concentrated during the rice transplanting and harvesting season. 3. The careless accident was more than 50% of total accident , and inevitable accident about 18% . The rate of careless accident showed the highest in pre-operation such as engine starting, check, and adjustment, and belt change. 4. The serious wounded operator was 7.1 % to total wounded operator , and about 50 % of accident of casualties to operators occurred during haruling operations. 5. The amount of casualties to property was range of 1,000 to 10,000 won, and annual total amount per unit tractor could be estimated to be 10 , 000 won.

• Journal of Biosystems Engineering
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• 제40권2호
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• pp.95-101
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• 2015

Purpose: During the start-up period, the response time of a hydraulic system increases in the winter because of the increased oil viscosity caused by the cold weather. The problems of delayed tractor starting and excessive wear of the clutch disk occur for these reasons. Therefore, this study develops an analysis model using the commercial hydraulic analysis program AMESim to examine the characteristics of delays in power shuttle starting at different oil temperatures. Methods: In the experiment, a tractor was stationary on a flat surface with the engine running at a constant speed of 1,080 rpm. The forward lever was then pressed to activate the power shuttle at three different oil temperatures, and the pressure changes were measured. The pressure on the forward clutch control valve was measured by a pressure gauge installed on the hydraulic line supplied to the transmission from the main valve. An analysis model was also developed and verified with actual tests. Results: The trend of the simulated pressures of the power shuttle is similar to that of the measured pressures, and a constant modulation period was observed in both the simulation and test results. However, the difference found between the simulation and test results was the initial pressure required to overcome the initial force of the clutch spring. Conclusions: This study also examines the characteristics of the delayed startup of the power shuttle at different oil temperatures through simulations.

• Journal of Biosystems Engineering
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• 제10권2호
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• pp.19-26
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• 1985

This study was carried out to develop a versatile data acquisition/processing system for overall tractor performance utilizing a NEC PC-8001 microcomputer. The data acquisition system measures drawbar pull and power, wheel torque and axle power, ground speed, wheel slip, fuel flow, and engine speed. The system stores hexadecimal data for these variables in memory. Upon completion of each test run, all hexadecimal data stored in memory are recorded on floppy disc. The data processing system reads in the data collected on floppy disc and interprete them using several graphical and statistical techniques. The system uses the same microcomputer and a dot-matrix printer. The data acquisition system has been installed on a GOLDSTAR 500 tractor (2WD, 50 ps). A field study has shown that tractor performance data can be quickly and easily collected. It also appeared that the data processing system can be used to efficiently analyze the collected data. The data acquisition system has some troublesome in mounting and handling on tractor since it uses a general-purpose computer consisting of several components.

• 한국기계가공학회지
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• 제20권8호
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• pp.67-73
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• 2021

In this study, we installed forward and reverse rotation rotavators on a tractor to measure the load in the field and analyze the power consumed. The rotavator is attached to the rear of the tractor and transmits the power applied from the power take off (PTO) of the tractor to the rotating shaft of the rotavator, and it plows or reverses the soil according to the rotational direction of the rotating shaft. Depending on the rotational direction of the rotavator, the power consumed in the tractor engine and the power transmitted to the tractor axle and rotavator also vary, thus, research of load and power is an essential factor in designing the system. As a field test results, 84.1-93.5% power was consumed by the forward rotation rotavator, and 37.8-57.5% power was consumed by the reverse rotation rotavator. In addition, depending on the rotation direction of the rotavator, the power consumed by the tractor was in the order of PTO and axle. Based on the research results, development of reliable rotavator systems would be possible in the future research.

• 한국산림과학회지
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• 제108권4호
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• pp.562-573
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• 2019

국내 임목수확작업에 사용되고 있는 트랙터 기반 소형 타워야더는 소경재 생산을 목적으로 개발되었으며, 중대경재 수확 체제로 변화함에 따라 견인 성능의 개선이 필요하다. 이 연구는 동력 전달방식을 기존의 기계식에서 기계 유압식으로 개선하여 타워야더의 최대 견인력을 비교·분석하였으며, 트랙터 엔진속도, 유압식 동력 전달 기구의 압력을 변수로 두고 견인 성능 실험을 실시하였다. 실험 수준은 트랙터 엔진속도(1,200, 1,400, 1,600, 1,800, 2,000, 2,200 rpm) 6수준, 동력 전달 기구의 압력(4.9, 6.9, 8.8 MPa) 3수준으로 선정하였다. 기존의 경우 최대 견인력은 엔진 회전속도 757 rpm에서 15,146.6 N의 최대견인력을 발휘하였으나 개선된 타워야더는 엔진 회전속도 1,575 rpm에서 36,140 N의 최대 견인력이 나타나, 최대 견인력이 2.4배 증가되었다. 이에 따라 중대경재 위주의 목재수확 현장에서 작업이 가능할 것으로 판단된다. 또한 기존 장비를 재활용하여 성능 개선함으로써 견인력이 큰 집재장비의 신규 도입 및 운영에 필요한 비용을 줄일 수 있을 것으로 기대된다.

• 드라이브 ㆍ 컨트롤
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• 제17권4호
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• pp.133-140
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• 2020

Traction performance of a tractor varies depending on soil conditions. Sinkage and slip of the driving wheel for tractor frequently occur in a reclaimed land. The objective of this study was to develop a tractor suitable for a reclaimed land. Traction performance was evaluated according to soil conditions of reclaimed land and paddy field. Field experiments were conducted at two test sites (Fields A: paddy field; and Field B: reclaimed land). The tractor load measurement system was composed of an axle rotation speed sensor, a torque meter, a six-component load cell, GPS, and a DAQ (Data Acquisition System). Soil properties including soil texture, water content, cone index, and electrical conductivity (EC) were measured. Referring to previous researches, the tractor traveling speed was set to B3 (7.05 km/h), which was frequently used in ridge plow tillage. Soil moisture contents were 33.2% and 48.6% in fields A and B, respectively. Cone index was 2.1 times higher in field A than in field B. When working in the reclaimed land, slip ratios were about 10.5% and 33.1% for fields A and B, respectively. The engine load was used almost 100% of all tractors under the two field conditions. Traction powers were 31.9 kW and 24.2 kW for fields A and B, respectively. Tractive efficiencies were 83.3% and 54.4% for fields A and B, respectively. As soil moisture increased by 16.4%, the tractive efficiency was lowered by about 28.9%. Traction performance of tractor was significantly different according to soil conditions of fields A and B. Therefore, it is necessary to improve the traction performance of tractor for smooth operations in all soil conditions including a reclaimed land by reflecting data of this study.

• 농업과학연구
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• 제49권4호
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• pp.897-907
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• 2022

The purpose of this study is to develop a self-propelled underground crop harvester and its performance was evaluated by measuring the load during actual potato harvesting operations. This study was conducted at a constant working speed of 1 km·h^-1. A load measurement system was installed to measure the actual load and the required working power was analyzed. A hydraulic pressure sensor was also installed to measure the hydraulic pressure. The required hydraulic power was calculated using the hydraulic pressure and flow rate. The results showed that the engine speed, torque, and power during harvesting operation were in the range of 845 - 1,423 rpm, 95 - 228 Nm, and 9 - 31 kW, respectively. Traction power, excluding the hydraulic pump of the tractor and power take-off (PTO) output, was in the range of 9 - 28 kW, and it was confirmed that it occupies a ratio of 16.2 to 50% of the engine rated output. The engine can supply the minimum required traction power to move the vehicle. This means that the engine used in this study could be down-sized to be suitable for an underground crop harvester. In this study, the gear stages of the tractor were not considered. This research thus shows the possibility of developing a self-propelled underground crop harvester.