• Title, Summary, Keyword: Exhaust gas temperature

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IDLE PERFORMANCE OF AN SI ENGINE WITH VARIATIONS IN ENGINE CONTROL PARAMETERS

  • Kim, D.S.;Cho, Y.S.
    • International Journal of Automotive Technology
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    • v.7 no.7
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    • pp.763-768
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    • 2006
  • Emission reduction in the cold start period of SI engines is crucial to meet stringent emission regulations such as SULEV Emissoin reduction is the starting point of the study in the which the variable valve timing (VVT) technology may be one promising method to minimize cold start emissions while maintaining engine performance. This is because it is possible to change valve overlap and residual gas fraction during cold start and idle operations. Our previous study showed that spark timing is another important factor for reducing cold-start emissions since it affects warm-up time of close-coupled catalysts (CCC) by changing exhaust gas temperature. However, even though these factors may be favorable for reduction of emissions, they may deteriorate combustion stability in these operating conditions. This means that the two variables should be optimized for best exhaust emissions and engine stability. This study investigated the effects of valve and spark timings in idle performance such as combustion stability and exhaust emissions. Experiments showed that valve timings significantly affected engine stability and exhaust emissions, especially CO and $NO_x$, due to change in residual gas fraction within the combustion chamber. Spark timing also affects HC emissions and exhaust gas temperature. Yet it has no significant effects on combustion stability. A control strategy of proper valve timing and spark timing is suggested in order to achieve a reduction in exhaust emissions and a stable operation of the engine in a cold start and idle operation.

EXHAUST GAS HEAT RECOVERY SYSTEM FOR PLANT BED HEATING IN GREENHOUSE PRODUCTION

  • Kim, Y.J.;Ryou, Y.S.;Rhee, K.J.;Kang, G.C.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • pp.639-646
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    • 2000
  • Hot air heater with light oil combustion is the most common heater for greenhouse heating in the winter season in Korea. However, since the heat efficiency of the heater is about 80%, considerable unused heat in the form of exhaust gas heat discharges to atmosphere. In order to capture this exhaust gas heat a heat recovery system for plant bed heating in the greenhouse was built and tested in the hot air heating system of greenhouse. The system consists of a heat exchanger made of copper pipes, ${\phi}\;12.7{\times}0.7t$ located inside the rectangular column of $330{\times}330{\times}900mm$, a water circulation pump, circulation plastic pipe and a water tame The total heat exchanger area is $1.5m^2$, calculated considering the heat exchange amount between flue gas and water circulated in the copper pipes. The system was attached to the exhaust gas path. The heat recovery system was designed as to even recapture the latent heat of flue gas when exposing to low temperature water in the heat exchanger. According to performance test it can recover 45,200 to 51,000kJ/hr depending on the water circulation rates of 330 to $690{\ell}$/hr from the waste heat discharged. The exhaust gas temperature left from the heat exchanger dropped to $100^{circ}C$ from $270^{circ}C$ by the heat exchange between the water and the flue gas, while water gained the difference and temperature increased to $38^{circ}C$ from $21^{circ}C$ at the water flow rate of $690{\ell}$/hr. And, the condensed water amount varies from 16 to $43m{\ell}$ at the same water circulation rates. This condensing heat recovery system can reduce boiler fuel consumption amount in a day by 34% according to the feasibility study of the actual mimitomato greenhouse. No combustion load was observed in the hot air heater.

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A Conversion Rate Prediction Study of Exhaust Gas by Catalyst Simulation in Heavy Duty Natural Gas Vehicle (대형천연가스차량에서 촉매시뮬레이션에 의한 배출가스의 변환율 예측 연구)

  • 한영출;오용석;강호인
    • Journal of Korean Society for Atmospheric Environment
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    • v.16 no.3
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    • pp.257-264
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    • 2000
  • An aftertreatment device which reduce exhaust gas of natural gas vehicle(NGV), NGV catalyst has important meaning as to reduce the exhaust emission. In this study, the characteristics of NGV catalyst were investigated and the effect parameters of NGV catalyst were analyzed and were predicted by changing the various parameters such as temperature, and gas concentration. The conversion efficiency of NGV catalyst converter was also predicted by Pd-loading, mass flow rate and gas composition.

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Effects of Oxygen Concentration on the NOx Emission of Non-premixed Flame in Hot Exhaust Gas (고온 배기가스의 산소농도가 비예혼합화염의 NOx 발생에 미치는 영향)

  • Sohn, Hwa-Seung;Kim, Ho-Young
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.26 no.6
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    • pp.833-841
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    • 2002
  • The present study examined the possibility of NOx reduction in the high temperature industrial furnaces, duct burner of gas turbine cogeneration and two-stage gas turbine combustor. The experimental study was carried out for the non-premixed flame of second stage combustor with the variations of oxygen concentration in the hot exhaust gas of first stage combustor. It also examined the flammability range, temperature and NOx, $CO_2$, $O_2$formation in the combustor with respect to oxygen concentration in which the fuel(natural gas) is supplying into the hot exhaust gas. The results show that the inner temperature of flame reaches 1,20$0^{\circ}C$ at EGR $O_2$23% and that 15ppm of NOx at EGR $O_2$15.5% increases up to 60ppm at EGR $O_2$23%. It is believed that Fenimore's prompt NOx mechanism is more influential on the NOx formation than Zeldovich's thermal NOx mechanism does.

A study on temperature characteristic of the gases supplied to SOFC system by utilizing the ship exhaust gas (선박 배기가스 활용에 따른 SOFC 시스템 공급가스의 온도특성에 관한 연구)

  • Park, Sang-Kyun
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.8
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    • pp.822-828
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    • 2013
  • Since the operating temperature of Solid Oxide Fuel Cell (SOFC) is high, the heat management of the gases supplied to fuel cell system is important. In this paper, the temperature characteristic of the gases supplied to the anode and the cathode of the fuel cell is studied in case of utilizing the waste heat contained in the ship exhaust gas as a heat source to heat up the fuel, gas and water supplied to a 500kW SOFC system for a ship power. For the fuel cell system proposed in this paper, the temperature of gases supplied to the anode and the cathode was the highest temperature at 963K when the exhaust gas of the fuel cell was utilized as the heat source for gases supplied to fuel cell system instead of utilizing the ship exhaust gas. In addition, the engine power did not effect on the temperature of gases supplied to the fuel cell stack.

COMPARISON OF HYDROCARBON REDUCTION IN A Sl ENGINE BETWEEN CONTINUOUS AND SYNCHRONIZED SECONDARY AIR INJECTIONS

  • Chung, S.-H.;Sim, H.-S.
    • International Journal of Automotive Technology
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    • v.3 no.1
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    • pp.41-46
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    • 2002
  • Effect of secondary air injection (SAI) on hydrocarbon reduction has been investigated in a single cylinder Sl engine operating at cold-steady/cold-start conditions. The hydrocarbon emission and exhaust gas temperature with and without catalytic converter were compared with continuous and synchronized SAIs, which injected secondary air intermittently into exhaust port. Effects of SAI location, SAI pressure, SAI timing, and location of catalytic converter have been investigated and the results are compared for both SAls with base condition. At cold-steady condition, the rate of HC reduction increased as the location of SAI was closer to the exhaust valve for both synchronized and continuous SAls. The emission of HC decreased with increasing exhaust-A/F when it was rich, and was relatively insensitive when it was lean. The timing of SAI in synchronized SAI had significant effect on HC reduction and exhaust gas temperature and the synchronized SAI was found to be more effective in HC reduction and exhaust gas temperature compared to the continuous SAI . At cold-start condition, when the catalytic converter was located 20 cm downstream from the exhaust port exit, the catalytic converter warm-up period for both SAls decreased by about 50%, and the accumulated hydrocarbon emission during the first 120 s decreased about by 56% and 22% with the synchronized and continuous SAIs, respectively, compared to that of the base condition.

Heat Recovery Characteristics of the Exhaust Heat Recovery System with Heat Pipe Unit Attached to the Hot Air Heater in the Greenhouse (히트파이프를 이용한 온풍난방기 배기열회수 시스템의 열회수 특성)

  • Kang, K. C.;Kim, Y. J.;Ryou, Y. S.;Baek, Y.;Rhee, K. J.
    • Journal of Biosystems Engineering
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    • v.26 no.5
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    • pp.441-448
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    • 2001
  • Hot air heater with light oil combustion is used as the most common heater for greenhouse heating in the winter season. However, exhaust gas heat discharged to atmosphere through chimney reaches up to 10~20% of total heat capacity of the oil burred. In order to recover the heat of this exhaust gas and to use for greenhouse heating, the heat pipe type exhaust heat recovery system was manufactured and tested in this experiment. The system consisted of a heat exchanger made of heat pipes, ø15.88${\times}$600mm located in the rectangular box of 675(L)${\times}$425(W)${\times}$370(H)mm, an air suction fan and air ducts. The number of heat pipe was 60, calculated considering the heat exchange amount between exhaust gas and air and heat transfer capacity of a heat pipe. The working fluid of heat pipe was acetone because acetone is known for its excellent heat transfer capacity. The system was attached to the exhaust gas path. According to the performance test it could recover 53,809 to 74,613kJ/h depending on the inlet air temperature of 12 to -12˚at air flow rate of 1.100㎥/h. The temperature of the exhaust gas left the heat exchanger dropped to 100$^{\circ}C$ from 270$^{\circ}C$ after the heat exchange between the suction air and the exhaust gas.

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The study of combustion gas characteristic by incinerator operation condition. (소각로 운영조건에 따른 연소배가스 특성 연구)

  • Lee, Keon-Joo
    • Journal of the Korea Organic Resources Recycling Association
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    • v.18 no.1
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    • pp.66-72
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    • 2010
  • This study was done to analyze the condition of combustion exhaust gas that is produced according to incinerator operating condition in A area Kyonggido. The boiler exhaust gas temperature, the oxygen concentration of boiler, the outgassing temperature of Semi Drying Sorber(SDS), the temperature of catalytic reactor, the concentration of NOx, SOx, CO, Hcl and Dust were investigated by change the temperature of incinerator. The concentration of SOx, CO, HCL and DUST were below 5 ppm as increase the temperature of incinerator however the concentration of NOx was increased from 40 ppm to 70 ppm as increase the temperature of incinerator. The boiler exhaust gas temperature and the temperature of catalytic reactor were not changed however the oxygen concentration of boiler was decreased gradually as increase the temperature of incinerator.

Effect of Recirculated Exhaust Gas Temperature on Performance and Exhaust Emissions in Diesel Engines with Scrubber EGR System (스크러버형 EGR시스템 디젤기관의 성능 및 배기 배출물에 미치는 재순환 배기온도의 영향)

  • 배명환;하태용;류창성;하정호;박재윤
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • pp.75-82
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    • 2002
  • The effects of intake mixture temperature on performance and exhaust emissions under four kinds of engine loads were experimentally investigated by using a four-cycle four-cylinder, swirl chamber type, water-cooled diesel engine with scrubber EGR system operating at three kinds of engine speeds. The purpose of this study is to develop the scrubber exhaust gas recirculation(EGR) control system for reducing $NO_x$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce NOx emissions. And a novel diesel soot-removal device with a cylinder-type scrubber which has five water injection nozzles is specially designed and manufactured to reduce soot contents in the recirculated exhaust gas to the intake system of the engine. The influences of cooled EGR and water injection, however, would be included within those of scrubber EGR system. In order to study the effect of intake mixture temperature, a intake mixture heating device which has five heating coils is made of a steel drum. It is found that the specific fuel consumption rate is considerably elevated by the increase of intake mixture temperature, and that NOx emissions are markedly decreased as EGR rates are increased and intake mixture temperature is dropped, while soot emissions are increased with increasing EGR rates and intake mixture temperature.

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Development of Grain Heater Using Engine Exhaust Gas (내연기관(內燃機關) 배기(排氣)가스를 이용(利用)한 곡물가열기(穀物加熱機) 개발(開發))

  • Suh, S.R.;Harris, F.D.
    • Journal of Biosystems Engineering
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    • v.10 no.2
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    • pp.1-11
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    • 1985
  • A double pipe grain heater using engine exhaust gas as a heat source was developed. The performance of the grain heater was examined with soybeans as a test material experimentally and numerically using a mathematical model constructed. The following conclusions were drawn: 1. The modified screw conveyor used in the grain heater has a characteristic of decreasing capacity with increasing speed at speeds above 60 rpm. Operation with speeds below 60 rpm is recommended. 2. Heating soybeans by the heater at soybean flow rate up to 100 kg/hr, inlet temperature of the exhaust gas to the heater are recommended as above $400^{\circ}C$, $300^{\circ}C$, and $200^{\circ}C$ roughly for a 2, 5, and 10 kW engine, respectively. 3. Temperature increments of soybean by the heater at soybean flow rates ranged from 25 to 100 kg/hr are in the ranges of $6^{\circ}C-35^{\circ}C$, $15^{\circ}C-88^{\circ}C$, and $15^{\circ}C-140^{\circ}C$ with exhaust gas from a 2, 5, and 10 kW engine, respectively, at an exhaust temperature of $500^{\circ}C$. 4. Thermal efficiency of the heater at soybean flow rates ranged from 25 to 100 kg/hr are in the ranges of 35-37%, 28-34%, and 20-29% with exhaust gas from a 2, 5, and 10 kW engine, respectively. 5. The grain heater can be used to heat the other grain, also, without any bad effect from the exhaust gas used as a heat source.

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