• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3341-3346
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• 2007

This paper presents effects of carburetor throttle angle on the performance characteristics of a small sparkignited, gasoline engine. The engine used in the test is a single cylinder, two-stroke, air-cooled 26cc SI engine for brush-cutter. We measured the rpm, torque, power, and fuel consumption according to the six different throttle angle conditions of the rotary-type carburetor and to the engine dynamometer loads. We had concluded that maximum power happened at 5000${\sim}$6000rpm and at the same condition was the minimum specific fuel consumption.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.711-714
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• 2008

The objective of this paper is to know the characteristics of pressure through a simplified typical carburetor used in small engines at the different throttle opening conditions. The carburetor is the device responsible for creating the right air-fuel mixture according to the different engine operating conditions. It is activated by the static or the dynamic pressure. The carburetor dummy is geometrically similar of LPG brush-cutter engine's diaphragm carburetor and is made of acrylic. Suction system gives body to crankcase vacuum using the vacuum pump and throttle opening conditions are controled by transfer device. Carburetor venturi throat and fuel charging tube diameter is each 20mm, 4.1mm. The result of the work presents an unprecedented phenomenon of suction pressure variation inside the carburetor venturi. It is predicted that these unprecedented pressure variation be caused by minor losses; sudden contraction or expansion, open or partially closed and so on.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2916-2921
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• 2008

This paper presents the performance and characteristics of small spark-ignited small 2-stroke engine. A single cylinder, two-stroke, air cooled 23cc SI engine for brush-cutter was used in this study. For the performance of the engine, rpm, torque, fuel consumption and lubricate oil consumption were measured, and also HC, CO, NOx emissions and excess air ratio according to throat open ratio under two lubrication method were measured and analyzed. The results showed that maximum of engine rpm is nearly same in both methods and also, torque, power is similar. exhaust emissions tend to decrease with throat open ratio.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.409-412
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• 2008

This paper presents the effects of excess air factors(0.84${\sim}$0.90) and opened throttle area ratios(AR=0.15${\sim}$0.25) on the emission and performance of a small spark-ignition gasoline engine. The engine used in this paper was a single cylinder, diaphragm carburetor, two-stroke, air-cooled 26cc engine for brush cutter. The rpm, torque, fuel consumption and CO emission were measured under the four different excess air factors and three different opened area ratios conditions on the engine loads respectively. The results showed that the rpm was decreased and torque was increased at increasing load, the maximum power and minimum fuel consumption could be obtained critical rpm on each throttle opened area ratios and brake specific fuel consumption was decreased 13${\sim}$17%, CO emissions was decreased 21${\sim}$38% at excess air factor 0.90 than 0.84.