• Journal of the Korean Society of Safety
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• v.34 no.1
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• pp.27-33
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• 2019

Combustion characteristics of gasoline/ethanol fuel were investigated both numerically and experimentally for vehicle fire safety. The numerical simulation was performed on the well-stirred reactor (WSR) to simulate the homogeneous gasoline engine and to clarify the effect of ethanol addition in the gasoline fuel. The simulating cases with three independent variables, i.e. ethanol mole fraction, equivalence ratio and residence time, were designed to predict and optimized systematically based on the response surface method (RSM). The results of stoichiometric gasoline surrogate show that the auto-ignition temperature increases but NOx yields decrease with increasing ethanol mole fraction. This implies that the bioethanol added gasoline is an eco-friendly fuel on engine running condition. However, unburned hydrocarbon is increased dramatically with increasing ethanol content, which results from the incomplete combustion and hence need to adjust combustion itself rather than an after-treatment system. For more tangible understanding of gasoline/ethanol fuel on pollutant emissions, experimental measurements of combustion products were performed in gasoline/ethanol pool fires in the cup burner. The results show that soot yield by gravimetric sampling was decreased dramatically as ethanol was added, but NOx emission was almost comparable regardless of ethanol mole fraction. For soot morphology by TEM sampling, the incipient soot such as a liquid like PAHs was observed clearly on the soot of higher ethanol containing gasoline, and the soot might be matured under the undiluted gasoline fuel.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.12
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• pp.1129-1135
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• 2013

In this, three types of natural gas were employed to investigate the effect of low-calorific natural gas on the performance of and emissions from a heavy-duty CNG engine. The performance and emission characteristics were analyzed by conducting a full-load test, WHSC mode test, and WHTC mode test. The results showed that the torque of low-calorific natural gas with $9,800kcal/Nm^3$ of higher heating value decreased by 4.4 compared to that of the current natural gas with $10,400kcal/Nm^3$ of heating value. With low-calorific fuels, CO, $CO_2$, and $NO_x$ emissions decreased. However, THC emissions increased. According to the WHSC and WHTC mode test results, the thermal efficiency increased and the emission characteristics showed a similar trend to the full-load test results. Low-calorific natural gases cause a decrease in torque at full-load operation conditions and an increase in hydrocarbon emissions.

• Journal of the Korean Wood Science and Technology
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• v.34 no.4
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• pp.22-30
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• 2006

The volatile organic compound (VOC) Analyzer is a portable device to measure the four main aromatic hydrocarbon gases: toluene, ethylbenzene, xylene and styrene. With the VOC Analyzer, a semiconductor gas sensor eliminates the need for the carrier gas which is required for conventional gas chromatographs. In addition, since the semiconductor gas sensor is supersensitive to gas components, it is not necessary to use a conventional gas concentrator or other complicated equipment. Compared with other measurement methods, the VOC analyzer is useful for measuring toluene, ethylbenzene, xylene and styrene in wood-based panel because of its ease in obtaining field results and repeating the test. The VOC Analyzer primarily measures four VOC in the air. In this study, we designed a test method of VOC measurement for particle board. A specimen was sealed in 3L polyester bag, after 96hours we could measure maximum VOC emission level that is a stabilized VOC Value. For easy, fast and economic testing of TVOC emission from wood-based panel, we developed the test method with the VOC Analyzer. The VOC Analyzer is expected to gain widespread use in the manufacturing field where a quick and easy test for VOC emission from wood-based panel is required. Furthermore, the VOC Analyzer promises to become an easier, faster and more economic technique than the currently used standard methods.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.65-72
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• 2007

The VOC (volatile organic compound) analyzer is devised to measure the four main aromatic hydrocarbon gases: toluene, ethylbenzene, xylene and styfene. It is not affected by ambient temperature and humidity. In addition, standby and measuring time of VOC Analyzer is a short as below 30 min and 8 min, respectively. Since the semiconductor gas sensor is supersensitive to gas components, it is not necessary to use a conventional gas concentrator or other complicated equipment. In this study, VOC emission behavior from 4 types paints (lacquer, urethane vanish, water-base paint, enamel paint) for wood-based panel was investigated using VOC Analyzer. After a specimen was spreaded on aluminum foil ($6.32{\times}6.32cm$) in $3{\ell}$ polyester bag, after 24 hours we could measure maximum VOC emission level that is a stabilized VOC value. Xylene of VOCs was high emitted from lacquer, urethane vanish and water-based paint, and TVOC (Toluene + Ethylbenzene + Xylene + Styrene) of lacquer was the highest emission concentration than another.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.10
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• pp.1147-1154
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• 2004

This paper is the third of several companion papers which compare the method of Air-Fuel ratio determination. In the previous works, Eltinge chart was expanded to arbitrary fuel composition as a reference exhaust composition. The compensation of unburned hydrocarbon in Eltinge chart and comparison of Spindt and Eltinge method were also discussed. In addition to Eltinge and Spindt's one, however, there are many methods which calculate Air-Fuel ratio from exhaust emission. Among these methods, carbon balance and oxygen balance are widely used in practice. In some applications, linear formula from statistical method is being used in the field due to its simplicity and convenience. In this paper, these various methods are evaluated and compared with Eltinge results and new linear formula is proposed for the gasoline fuel. The results show that the corrected carbon balance equation has excellent agreement with Eltinge and Spindt's one. On the other hands, the oxygen-balanced formula has a limitation according to the mixture state and AFR. For gasoline fuel, newly proposed linear equation has good compatibility with Eltinge and Spindt up to AFR 17.

• Journal of Energy Engineering
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• v.11 no.2
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• pp.178-185
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• 2002

The object of this paper is to investigate the effects of early fuel evaporators on cold driveability of gasoline passenger cars. Experiment has been carried out for the assessment cold start performance and cold driveability. And fuel consumption rate, emission and cylinder pressure were measured. On the base of combustion pressure of cylinder, rate of heat release, cumulative heat release amount and burned mass fraction are evaluated. The results show that fuel consumption rate is increased by 17.7%, monoxide and hydrocarbon were reduced by 23% and by 45% respectively, fluctuations of indicated mean effective pressure and maximum combustion pressure were increased by 4∼6%, fuel consumption rate per power was improved by 0.2∼2.3%. These are caused by the fact maximum heat release period and main combustion period are getting short.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.5
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• pp.31-38
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• 2009

Supercharging system was adopted to investigate the influence of boost pressure on operating range and exhaust emissions by using a supercharger at low temperature diesel combustion (LTC) condition in a 5-cylinder 2.7 L direct injection diesel engine. The experimental parameters such as injection quantity, injection timing, injection pressure and exhaust gas recirculation (EGR) rate were varied to find maximum operating range in LTC condition. As a result of adopting increased boost pressure in LTC, wider operating range was achieved compared with naturally aspirated condition due to increased mixing intensity. Increased boost pressure resulted in lower hydrocarbon (HC) and carbon monoxide (CO) emissions due to increased swirl rate and mixing intensity, which induced complete combustion. Moreover, increased boost pressure in LTC resulted in much lower soot emissions compared with high speed direct injection (HSDI) condition.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.5
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• pp.53-60
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• 2009

In this study, LPG-blended DME fuel was experimentally investigated in CI(compression ignition) engine. In particular, performance, emissions characteristics (including hydrocarbon, CO, and NOx emissions), and combustion stability of engine fueled with LPG-blended DME fuel were examined. The extent of LPG fuel in the blended fuel was 0-40 wt%. Results showed that stable engine operation was possible in a wide range of engine loads on DME blended with maximum 30% of LPG by mass in a CI engine. Considering the results of the engine power output and exhaust emissions, blended fuel up to 30% of LPG by mass can be used as an alternative to diesel in a CI engine. LPG blended DME fuel is expected to have potential for enlarging the DME market.

• Journal of environmental and Sanitary engineering
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• v.17 no.2
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• pp.11-17
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• 2002

Diesel particulate matter (DPM) is known to be one of the major harmful emissions produced by diesel engines. The majority of diesel particles are in the range of smaller than $I{\mu}\textrm{m}$. Because of their tiny volume, ultrafine diesel particles contribute very little to the total mass concentration which is currently regulated for automobile emissions. Diesel particles are known to have deleterious effects upon human health because they penetrate human respiratory tract and have negative effects on the health. The measurement of the number distribution of nanometer size particles (nanoparticles) in the diesel exhaust emission is important in order to evaluate their environmental and health impact, and to develop new types of diesel particulate filters. In this study, we directly sampled particulate matters emitted from a diesel truck mounted on the chassis dynamometer by a flow separator and dilution system, and measured the nanoparticles using two types of differential mobility analyzers combined with a Faraday cup electrometer (FCE) and a condensation particle counter (CPC). The particle size distributions were analyzed by changing engine operation condition, i.e. ratio of engine loading. The total number concentration of particles were increased with the engine loading ratio and the nanoparticles (less than 50nm) were affected by hydrocarbon (HC) concentration in the diesel exhaust.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.1
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• pp.80-89
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• 1998

The residual gas in an spark-ignition engine is one of important factors on emissions and performance such as combustion stability. With high residual gas fractions, flame speed and maximum combustion temperature are decreased and these are deeply related with combustion stability especially at idle and NOx emission at relatively high engine load. Therefore, there is a need to characterize the residual gas fraction as a function of the engine operating load. Therefore, there is a need to characterize the residual gas fraction as a function of the engine operating parameters. In the present study, the quantitative measurement technique of residual gas fraction was studied by using Fast Response Flame Ionization Detector(FRFID). The measuring technique and model for estimation of residual gas fraction were reported in this paper. By the assuming that the raw signal from FRFID saturates with the same slope for firing and misfiring cycle, in-cylinder hydrocarbon(HC) concentration can be estimated. Residual gas fraction can be obtained from the in-cylinder HC concentration measured at firing and motoring condition. The developed measurement and calibration procedure were applied to the limited engine operating and design condition such as intake manifold pressure and valve overlap. The results show relevant trends by comparing those from previous studies.