• Journal of Biosystems Engineering
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• v.26 no.4
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• pp.323-330
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• 2001

The regular maintenance and repair status of major farm machinery such as power tiller, farm tractor, rice transplanter and combine harvester etc., were surveyed and analyzed for the full-time farmers in order to get basic information for promoting farm machinery productivity. The survey was carried out through 209 farmers from 9 provinces. The results of this study can be summarized as follows; 1. The regular maintenance of farm machinery was conducted at repair shop(49.5%) or dealer agency(12.0%), and also conducted by farmers at their house(34.9%). 2. For the status on the cleanness or exchange times of engine oil, fuel filter and air cleaner, most farmers conducted fewer times than the necessary times. And, 5.3%, 7.7%, and 2.9% of surveyed farmers experienced breakdowns due to the insufficient cleanness or exchange oil, fuel filer, and air cleaner, respectively. 3. Most farmers(76.1%) recognized the necessity of farm machinery training or education, and they preferred one week for the training period, simple or easy maintenance for the training level, agricultural technical center or farm machinery manufacturer for the training agency. 4. Complete recognition of operation manual and sufficient maintenance before-, during-, and after-operation for the farm machinery can minimize the breakdowns, enlarge the endurance prevent the safety accidents, and promote productivity of farm machinery. And, these can be accomplished by the thorough training or education for agricultural machinery.

• Applied Biological Chemistry
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• v.17 no.4
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• pp.235-239
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• 1974

Rice root activiators (phthalamic acid (PA) and p-chlorophenyl PA (PCPPA) were tested in pot culture for their effects on yield of IR667-Suwon 214 weak in root activity. The results were as follows: 1) Maximum percentage yield increase was 36.7% with organic matter applied and 13.3% without organic matter in 100 ppm (90ml/0.05$m^2$) of PCPPA treatment. 2) Root activators increased oxidizing power of root (root activity), consequently gave a balanced nutrient uptake, stimulated root growth and subsequent shoot growth. 3) Root activators increased number of panicle per hill, grain weight, filled grain ratio and effective tiller ratio.

• Journal of Biosystems Engineering
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• v.8 no.1
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• pp.9-16
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• 1983

This study was conducted to find out the effects of such parameters as specific draft resistance, slip rate, and fuel consumption rate on plowing performance in paddy fields spread with chopped rice straw. The plowing operation by an 8 P.S. power tiller was carried out in 6 different fields having the soil moisture content of 27~36 percent in dry basis in clay loam soil texture, and applying chopped rice straw of 10, 20, 30 and 60cm in length in the spring of 1982. The effects of soil hardness and moisture content on the plowing performance were also investigated. The results of the study are summarized as follows; 1. The minimum draft during the plowing operation was 110kg in the 30cm rice straw plot having the soil moisture content of 32 percent in dry basis. 2. The multiple regression equation of the specific draft(D) as a function of soil moisture content(M) and cutting length of rice straw(L) was obtained as follows. $D=14.1978-0.8565M+0.0661LxM-2.9685L+0.0133M^2+1.093L^2$ 3. In the 30cm rice straw plot with the soil moisture content of 32 percent in dry basis, the minimum specific draft resistance and the rate of slip were 0.35kg per $cm^2$ and 16 percent respectively. The specific draft resistance varied sensitively in accordance with the soil moisture content, and the slip rate of power tiller was dependent upon the cutting length of rice straw rather than the soil moisture content. 4. The highest plowing performance was 5.3 ares per hour at the soil moisture content of 35 percent and soil hardness of 10kg per $cm^2$. The relationship between the plowing performance and the soil moisture content was obtained by a quadratic equation. 5. The minimum fuel consumption rate in the plowing operation was recorded 6.5 liters per 10 ares in 30cm chopped rice straw plot with the soil moisture content of 32 percent in dry basis.

• Journal of Biosystems Engineering
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• v.6 no.2
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• pp.1-8
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• 1982

The objective of this study was to find out the technical feasibility of ethanol-diesel fuel blends as a diesel engine fuel. Fuel properties essential to the proper operation of a diesel engine were determined for blends containing several concentrations of ethanol in No. 2 diesel fuel. A single-cylinder diesel engine for a power tiller was used for the engine tests, in which load, speed and fuel consumption rate were measured. The fuels used in tests were No. 2 diesel fuel and a blend containing 10-percent ethanol and 90-percent No. 2 diesel fuel. The results of the study are summarized as follows. 1. It was not possible to blend ethanol and No. 2 diesel fuel as a homogeneous solution even though anhydrous ethanol was used. The problem of blending ethanol in No. 2 diesel fuel could be solved by adding butanol about 5% of the amount of ethanol in the blends. 2. Because ethanol had a much lower boiling point ($78.3^{\circ}C$ under atmospheric pressure) than a diesel fuel, it was necessary to store ethanol-diesel fuel blends airtight in order to prevent them from evaporation losses of ethanol. 3. The addition of ethanol to No. 2 diesel fuel lowered the fuel viscosity and the cetane rating, but a blend of 10% ethanol and 90% diesel fuel had a viscosity and a cetane rating well above the KS minimum values for No. 2 diesel fuel. 4. At the rated speed, the specific fuel consumption of No.2 diesel fuel was lower than that of the 10% ethanol blend for the almost entire range of load. However, under the overload condition the specific fuel consumption was lower for the 10% ethanol blend. 5. Under the variable-speed full-load tests, both fuels produced approximately the same torque and power. At the speeds of 1600rpm or below, the specific fuel consumption of No. 2 diesel fuel was lower than that of the 10% ethanol blend. At the speeds of 1600rpm or above, however, the specific fuel consumption was lower for the 10% ethanol blend. 6. At the ambient temperature above $15^{\circ}C$, the use of the 10% ethanol blend in the engine created a vapor lock in the fuel injection pump and stalled the engine. The vapor locking problem was overcome by chilling the surroundings of the fuel injection pump and the cylinder head with water.

• Korean Journal of Agricultural Science
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• v.17 no.1
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• pp.45-51
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• 1990

This study was conducted to obtain basic data for the design of cooling system by the test of engine performance of the power tiller being used widely in the rural area. Among the various factors affecting engine performance, the flow rate of cooling water was considered as the major factor in this study. Motoring loss, output, fuel consumption ratio, torque, heat absorption of cooling water, and thermal efficiency were measured and analyzed based on three flow rates of cooling water such as 15, 20, and $25{\ell}/min$. The results obtained were as follows : 1. Motoring loss of the engine was 1.371 kW at 2,200 rpm., and mechanical efficiency was 79.1% at rated output level. 2. Output power of the engine increased with the flow rate of cooling water increased. 3. BSFC was 282.9g/kW-h at the flow rate of $20{\ell}/min$, and the temperature of cooling water at outlet was $80.9^{\circ}C$. 4. There was a little variation of torque of the engine depending on the flow rate of cooling water. 5. Absorption of heat by cooling water was increased with the increase of flow rate. 6. The highest thermal efficiency of 32.3% at the flow rate of $20{\ell}/min$ was observed.

• Journal of Practical Agriculture & Fisheries Research
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• v.5 no.1
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• pp.64-76
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• 2003

This study was conducted in order to find out the basic data and informations for the accidents for repairing of agricultural machines. This study was summarized as fellows : 1. Among the total repair work, the ratio of repair accident was 68.9% and the accident ratio with power tiller, tractor, and combine was 84.8%. The accident occurred frequently in April to May and September to October because of frequent use of machines during this months. The accidents occurred often of ten to eleven and two to three afternoon in a day. 2. The 36.3% of the accident types was farming machines and the 60.4% of the accident occurred in yard of repair shop. The 34.4% of accident was caused by people, 26.2% by machines, 24.9% by environmental factors, and 14.5% by others. 3. In accident damage, human damage was 98.4% and economic damage was 43.6%. There was only 40.2% in having agricultural machinery insurance and 22.5% of research applicant answered that they would not have insurance in the future. 4. The 58.2% of the injured parts occurred in fingers, hands, wrists, or arms and the 74.4% of the damage types were bruise, prick or abrasion. The damaged parts of machinery were belt of power transmission device, chains, sharpened knives, narrow mechanism or cultivating knives for rotary. 5. The average days of medical treatment for casualty was 15.5 days and the average expense of medical treatment per person was 189,200 won. The days of temporary rest and the economic damage per person due to accident were 12.8 days and 469,300 won.

• Korean Journal of Agricultural Science
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• v.13 no.2
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• pp.265-278
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• 1986

This study was attempted to improve the thermal efficiency of 6 kW water-cooled diesel engine on power tiller. The engine performance tests were conducted to find out the effect of cooling water capacity of 2700cc, 2800cc, 2900cc, 3000cc, 3100cc on power, brake specific fuel consumption (BSFC), torque, temperature of cooling water and lubricating oil and friction losses of the engine with D. C. dynamometer. The results obtained in the study are summarized as follows: 1. The performance of the engine tested was adequated to Korea Industrial Standard but actual economy power was 10% higher than the labeled rated power of the engine. The BSFC of the engine tested 297.8g/kW-h which is belong a little higher level than hreign products. The temperature of cooling water was $101^{\circ}C$ which is higher than SAE standard ($88^{\circ}C$) 2. The friction losses of engine tested was 3.656 kW at 2200 rpm of rated rpm (piston speed 6.97m/sec) and is higher than those of foreign products. 3. When the cooling water capacity was increased from 2700cc to 3100cc the power output of the engine was increased from 6.7 kW to 7.13 kW at the rate of 6.4% and also the torque of the engine was increased from 28.85 N.m to 30.76 N.m at the rate of 6.39%. 4. When the cooling water capacity was increased from 2700cc to 3100cc, the BSFC was decreased 6.9g/kW-h from 310.9g/kW-h to 304.1g/kW-h, and after one half hour operation with full load, the temperature of cooling water was decreased $13^{\circ}C$ from $101^{\circ}C$ to $88^{\circ}C$ and also the temperature of lubricant oil was decreased $6.4^{\circ}C$ from $76.7^{\circ}C$ to $70.4^{\circ}C$. 5. The mechanical efficiency was increased from 70.08% to 71.08% when the cooling water capacity was increased from 2700cc to 3100cc.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.437-444
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• 2012

This study was aimed to minimized the impact force and vibration transmitted to transporting agricultural product from the power tiller trailer by installing vibration absorption device. The vibration absorbable trailer (I) mounted with leaf spring suspension and shock absorber was developed and compared on vibration absorption performance with the existing trailer (E) equipped no vibration absorption device. In order to identify the vibration absorption effect of the trailer developed in this study, the vibration accelerations, occurred during driving on paved road with loading 360 kg of pear, were measured and analyzed using FFT analyzer. The magnitude of average vibration acceleration was decreased highly for the improved trailer mounted with vibration absorption device in comparing with existing trailer in the frequency range under 60 Hz and under 80 Hz. And similar vibration absorption effect was represented for the improved trailer in all frequency range. Especially, in the frequency range between 40 Hz and 80 Hz, the magnitude of vibration acceleration for the improved trailer was decreased with 1/3 times in comparing with existing trailer. So, the transporting loss including damage of agricultural product could be decreased highly by using the improved vibration absorbable trailer mounted with leaf spring suspension and shock absorber simultaneously, designed in this study.

• Current Research on Agriculture and Life Sciences
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• v.22
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• pp.19-27
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• 2004

Cultivation area of garlics is 9% of all cultivation area of vegetables. The amount of annual demand is increased in 1,000~1,500ton. Also, the amount of demand per person has a tendency to increase as above 10kg. So, garlics has become important crops in agriculture. The purpose of this study is to acquire the basic information to design the garlic seeder attached power tiller. We used Working Model 3D program to design an automatic aligning device which is the most important part of the garlic seeder. The results are as follows; 1. The optimum depth of garlics seeding was shown as 3cm. 2. The garlic seed has to he discharged from the garlic seeder at intervals of 0.75sec in order to seed at intervals of seeds of 15cm. 3. The optimum design factors of the automatic aligning device were shown as cylinder diameter of 4cm, cylinder gap of 1cm, revolution of 36rpm and inclined angle of cylinder of $8.4^{\circ}$.

• Journal of Drive and Control
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• v.20 no.4
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• pp.115-122
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• 2023

This study utilized a discrete element method (DEM) simulation, as one of the virtual field trials, to predict the impact of tillage depth on the rotary blade shaft during rotavator tilling. The virtual field for the simulation was generated according to soil properties observed in an actual field. Following the generation of particles for the virtual field, a sequence of calibration steps followed to align the mechanical properties more closely with those of real soil. Calibration was conducted with a focus on bulk density and shear torque, resulting in calibration errors of just 0.02% for bulk density and 0.52% for shear torque. The prediction of the load on a rotary tiller's blade shaft involved a three-pronged approach, considering shaft torque, draft force, and vertical force. In terms of shaft torque, the values exhibited significant increases of 42.34% and 36.91% for every 5-centimeter increment in tillage depth. Similarly, the vertical force saw substantial growth by 40.41% and 36.08% for every 5-centimeter increment. In contrast, the variation in draft force based on tillage depth was comparatively lower at 18.49% and 0.96%, indicating that the effect of tillage depth on draft force was less pronounced than its impact on shaft torque and vertical force. From a perspective of agricultural machinery research, this study provides valuable insights into the DEM soil modeling process, accounting for changes in soil properties with varying tillage depths. These findings are expected to be instrumental in future agricultural machinery design studies.