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  • Title/Summary/Keyword: Fuel pressure control

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A Study on the Improvement of Combustion Stability for SI Engine at Idle Operation (SI 기관의 공회전시 연소 안정성 향상에 관한 연구)

  • Lee, J.S.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.6
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    • pp.259-266
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    • 1998
  • In the SI engine, the improvement of combustion stability is important not only for the fuel consumption rate but also for the emission control at idling of engine. Thus the engine speed fluctuation at idle operation mainly comes from cyclic variation of combustion in the SI engine. In this syudy, the improvement of combustion stability for the SI engine at idle condition by the cooling water temperature, duty ratio of ISC, spark ignition timing as well as the reducement of the harmful exhaust gas emission was discussed.

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Influence of the Type of Curing Agent on Swelling Behavior of Natural Rubber Foam (가교제의 종류가 천연고무 발포체의 팽윤거동에 미치는 효과)

  • Lee, Hwan-Kwang;Chung, Tea-Kyung;Kim, Sung-Chan;Kim, Hyun-Gi;Choi, Kyung-Man;Kim, Young-Min;Han, Dong-Hun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.6
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    • pp.1775-1781
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    • 2008
  • The effects of the type of curing agent on the swelling of the natural rubber(NR) sponge applicable to the self-sealing layer of a helicopter fuel tank were investigated. The curing systems employed were peroxide and mixed ones of sulfur and peroxide. The NR compounds were prepared in a kneader and a roll-mill. The compounds were partially cured in a press at high pressure and subsequently cured fully with expansion in another press at atmospheric pressure. The apparent density of the NR sponge was measured and the cell structure was observed with scanning electron microscopy. The swelling experiments were performed at room temperature using toluene, iso-octane, and an aircraft fuel as a solvent. More rapid volume swelling of the NR sponge cured by peroxide was achieved than cured by sulfur and peroxide with similar amount of curing agent added in rubber compounds. The apparent density and cell structure of the sponge were extremely sensitive to the amount of peroxide, which influences again the swelling behavior of the NR sponge. It is important to control properly two reactions of decomposition of foaming agent and crosslinking of NR in the mold to obtain rapid swelling of the NR sponge on contact of the fuel.

Nonlinear Static Model-based Feedforward Control Algorithm for the EGR and VGT Systems of Passenger Car Diesel Engines (승용디젤엔진의 EGR, VGT 시스템을 위한 비선형 정적 모델 기반 피드포워드 제어 알고리즘 설계)

  • Park, Inseok;Park, Yeongseop;Hong, Seungwoo;Chung, Jaesung;Sohn, Jeongwon;Sunwoo, Myoungho
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.6
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    • pp.135-146
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    • 2013
  • This paper presents a feedforward control algorithm for the EGR and VGT systems of passenger car diesel engines. The air-to-fuel ratio and boost pressure are selected as control indicators and the positions of EGR valve and VGT vane are used as control inputs of the EGR and VGT controller. In order to compensate the non-linearity and coupled dynamics of the EGR and VGT systems, we have proposed a non-linear model-based feedforward control algorithm which is obtained from static model inversion approach. It is observed that the average modeling errors of the feedforward algorithm is about 2% using stationary engine experiment data of 225 operating conditions. Using a feedback controller including proportional-integral, the modeling error is compensated. Furthermore, it is validated that the proposed feedforward algorithm generates physically acceptable trajectories of the actuator and successfully tracks the desired values through engine experiments.

A Study on Applying PID Control to a Downdraft Fixed Bed Gasifier using Wood Pellets

  • Park, Bu-Gae;Park, Seong-Mi;Park, Sung-Jun
    • Journal of the Korean Society of Industry Convergence
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    • v.25 no.2_1
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    • pp.149-159
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    • 2022
  • Biomass is material that is comprehensive of carbonaceous materials from plants, crops, animals, and algae. It has been used as one of heating fuel since the beginning the emergence of human beings. Since biomass is regarded as carbon-neutral energy source, it has recently been attracting attention as an energy source that can replace fossil fuels. The most widely applied field is distributed power generation, and a method of generating electric power by driving an internal combustion engine with syngas produced by gasifier is chosen. While the composition of the syngas produced in gasifiers changes depending on the air flowing into the reactor, commercialized gasifiers so far do not control the air flowing into the reactor. When the inner pressure in reactor increases, the air sucked into the reactor is reduced. That change of amount of air makes the composition of syngas varied. Those variations of composition of syngas cause the incomplete combustion hence the power output of engine drops, which is a critical weakness of the gasification technology. In this paper, to produce the uniformly composed syngas, PID control is applied. The result was shown when the amount of air into the reactor is supplied with the constant amount using PID control, the standard deviation of caloric values of syngas is around 2[%] of its average value. Meanwhile the gasifier without PID control has the standard deviation of caloric values is around 7[%]. Therefore, Adopting PID control to supply constant air to the gasifier is highly desirable.

A Research on Characteristics of Semi-active Muffler Using Difference of Transmission Paths (전달경로의 차이를 이용한 차량용반능동형 머플러의 특성에 관한 연구)

  • 이종민;김경목;손동구;이장현;황요하
    • Journal of KSNVE
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    • v.11 no.3
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    • pp.401-409
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    • 2001
  • Passive type mufflers installed on every car haute inherent problem of lowering engine power and fuel efficiency caused by backpressure which is byproduct of complex internal structure. Recent improvements like installing a calve to change exhaust gas path depending on power requirement and rpm have only marginally improved performance. Tremendous amount of recent research works on active exhaust noise control have failed to commercialize because of numerous physical and economical reasons. In this paper, a unique seal-active muffler using difference of transmission paths is presented. In this system exhaust pipe is divided into two and joined again downstream. Exhaust noise is reduced by destructive interference when two-divided noise join again with transmission paths'difference which is half of the wavelength of a main noise frequency. One divided path has a sliding mechanism to change length thereby transmission path length difference is adjusted to entwine rpm change. The proposed system has minimal backpressure and does not need a secondary sound source like a speaker so it can overcome many problems of failed active noise control methods. We have verified proposed system's superior performance by simulation and comparison experiment with passive mufflers.

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Analysis of In-cylinder Flow in a Miller Cycle Engine with Variable IVC for HEV (밀러사이클 적용 HEV 엔진 실린더의 가변흡기밸브 닫힘각에 따른 실린더내 유동해석)

  • Kim, Sangmyeong;Sung, Gisu;Lee, Jinwook
    • Journal of ILASS-Korea
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    • v.19 no.1
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    • pp.25-32
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    • 2014
  • For reduction of CO2 emission emitted from combustion engine, the developed nations have been focused on R&D of hybrid electric vehicle. Further more, many automobile companies are researching on various techniques related to engine used in HEV to enhance fuel economy. One of key techniques is miller cycle that control a valve timing to reduce compression stroke for saving energy and increase expansion stroke for high power. In this study, it was investigated the in-cylinder flow characteristics of miller cycle with variable intake valve timing by using the ANSYS simulation code. For simulation, the key analytic parameter defined as intake valve closing timing and cam profile. As main results, it was shown that LIVC cause a lower pressure inside cylinder and had better control turbulence intensity.

EFFECT OF MIXTURE PREPARATION IN A DIESEL HCCI ENGINE USING EARLY IN-CYLINDER INJECTION DURING THE SUCTION STROKE

  • Nathan, S. Swami;Mallikarjuna, J.M.;Ramesh, A.
    • International Journal of Automotive Technology
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    • v.8 no.5
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    • pp.543-553
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    • 2007
  • It is becoming increasingly difficult for engines using conventional fuels and combustion techniques to meet stringent emission norms. The homogeneous charge compression ignition(HCCI) concept is being evaluated on account of its potential to control both smoke and NOx emissions. However, HCCI engines face problems of combustion control. In this work, a single cylinder water-cooled diesel engine was operated in the HCCI mode. Diesel was injected during the suction stroke(0 to 20 degrees aTDC) using a special injection system in order to prepare a nearly homogeneous charge. The engine was able to develop a BMEP(brake mean effective pressure) in the range of 2.15 to 4.32 bar. Extremely low levels of NOx emissions were observed. Though the engine operation was steady, poor brake thermal efficiency(30% lower) and high HC, CO and smoke were problems. The heat release showed two distinct portions: cool flame followed by the main heat release. The low heat release rates were found to result in poor brake thermal efficiency at light loads. At high brake power outputs, improper combustion phasing was the problem. Fuel deposited on the walls was responsible for increased HC and smoke emissions. On the whole, proper combustion phasing and a need for a well- matched injection system were identified as the important needs.

Experimental Study on Single Channel DPF Device Applying the Method of Internal 2-Way Rotary Valve (회전형 밸브를 적용한 단일채널내 2-Way 방식의 DPF장치에 대한 실험적 연구)

  • Ham, Seong-Hun;Youm, Kwang-Wook
    • Journal of the Korean Institute of Gas
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    • v.19 no.6
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    • pp.110-115
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    • 2015
  • In this paper it is proposed to solve the problem of particulate matter reducing apparatus of the current DPF. One exhaust gas passage 2-way controlled to purify the exhaust gas generated during combustion efficiently. Through the control of the rotary valve within a single device, it is possible to prevent the exhaust pressure increases due to particulate matter accumulate inside the developing DPF. Develop DPF device capable of inducing a high efficiency of the output in order to improve the problem of reducing the engine output and fuel efficiency.

FPGA application for wireless monitoring in power plant

  • Kumar, Adesh;Bansal, Kamal;Kumar, Deepak;Devrari, Aakanksha;Kumar, Roushan;Mani, Prashant
    • Nuclear Engineering and Technology
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    • v.53 no.4
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    • pp.1167-1175
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    • 2021
  • The process of automation and monitoring in industrial control system involves the use of many types of sensors. A programmable logic controller plays an important role in the automation of the different processes in the power plant system. The major control units are boiler for temperature and pressure, turbine for speed of motor, generator for voltage, conveyer belt for fuel. The power plant units are controlled using microcontrollers and PLCs, but FPGA can be the feasible solution. The paper focused on the design and simulation of hardware chip to monitor boiler, turbine, generator and conveyer belt. The hardware chip of the plant is designed in Xilinx Vivado Simulator 17.4 software using VHDL programming. The methodology includes VHDL code design, simulation, verification and testing on Virtex-5 FPGA hardware. The system has four independent buzzers used to indicate the status of the boiler, generator, turbine motor and conveyer belt in on/off conditions respectively. The GSM is used to display corresponding message on the mobile to know the status of the device in on/off condition. The system is very much helpful for the industries working on plant automation with FPGA hardware integration.

Aerodynamic control capability of a wing-flap in hypersonic, rarefied regime: Part II

  • Zuppardi, Gennaro;Vangone, Daniele
    • Advances in aircraft and spacecraft science
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    • v.4 no.5
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    • pp.503-514
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    • 2017
  • The attitude control of an aircraft is usually fulfilled by means of thrusters at high altitudes. Therefore, the possibility of using also aerodynamic surfaces would produce the advantage of reducing the amount of fuel for the thrusters to be loaded on board. For this purpose, Zuppardi already considered some aerodynamic problems linked to the use of a wing flap in a previous paper. A NACA 0010 airfoil with a trailing edge flap of 35% of the chord, in the range of angle of attack 0-40 deg and flap deflections up to 30 deg was investigated. Computer tests were carried out in hypersonic, rarefied flow by a direct simulation Monte Carlo code at the altitudes of 65 and 85 km of Earth Atmosphere. The present work continues this subject, considering the same airfoil and free stream conditions but two flap extensions of 45% and 25% of the chord and two flap deflections of 15 and 30 deg. The main purpose is to compare the influence of the flap dimension with that of the flap deflection. The present analysis is carried out in terms of: 1) percentage variation of the global aerodynamic coefficients with respect to the no-flap configuration, 2) increment of pressure and heat flux on the airfoil lower surface due to the Shock Wave-Shock Wave Interaction (SWSWI) with respect to the same quantities with no SWSWI or in no-flap configuration, 3) flap hinge moment. Issues 2) and 3) are important for the design of the mechanical and thermal protection system and of the flap actuator, respectively. Under the above mentioned test and geometrical conditions, the flap deflection is aerodynamically more effective than the flap extension, because it involves higher variation of the aerodynamic coefficients. However, tests verify that a smaller deflection angle involves the advantage of a smaller increment of pressure and heat flux on the airfoil lower surface, due to SWSWI, as well as a smaller hinge moment.