• Title/Summary/Keyword: Liquid phase LPG injection engine

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Fundamental Study on Liquid Phase LPG Injection System for Heavy-Duty Engine (I) (대형엔진용 액상분사식 LPG 연료공급 방식에 대한 기초연구 (1))

  • 김창업;오승묵;강건용
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.4
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    • pp.85-91
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    • 2001
  • LPG has been well known as a clean alternative fuel for vehicles. As a fundamental study on liquid phase LPG injection (hereafter LPLI) system application to heavy-duty engine, engine output and combustion performance were investigated with various operating conditions using a single cylinder engine equipped with the LPLI system. Experimental results revealed that no problems were occurred in application of the LPG fuel to heavy-duty engine, and that volumetric efficiency and engine output, by 10% approximately, were increased with the LPLI system. It was resulted from the decrease of the intake manifold temperature through liquid phase LPG fuel injection. These results provided an advantage in the decrease of the exhaust gas temperature, in the control of knocking phenomena, spark timing and compression ratio. The LPLI engine could normally operated under $\lambda$=1.5 or EGR 30% condition. The optimized swirl ratio for the heavy duty LPG engine was found around R_s$ = 2.0.

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Injector Control Logic for a Liquid Phase LPG Injection Engine (액상 LPG 분사 엔진의 인젝터 제어 로직)

  • 조성우;민경덕
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.5
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    • pp.15-21
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    • 2003
  • The liquid phase LPG injection engine is a new technology to make good use of LPG as a clean energy. However, it is difficult to precisely control air/fuel ratio in the system because of variation of fuel composition, change of temperature and flash boiling injection mechanism. This study newly suggests an injector control logic for liquid phase LPG injection systems. This logic compensates a number of effects such as variations of density, stoichiometric air/fuel ratio, injection delay time, injection pressure, release pressure which is formed by flash boiling of fuel at nozzle exit. This logic can precisely control air/fuel ratio with only two parameters of intake air flow rate and injection pressure without considering fuel composition, fuel temperature.

Top-Feed Type Port Fuel Injector for Liquefied Petroleum Gas Liquid Phase Injection (Top-Feed Type 인젝터의 액상분사 LPG연료 분사장치 적용)

  • Yeom, Ki-Tae;Park, Jung-Seo;Bae, Choong-Sik;Park, Jeong-Nam;Kim, Sung-Kun
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.6
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    • pp.30-37
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    • 2007
  • The injection and spray characteristics of top-feed type injector was investigated under liquid phase injection fueled with liquefied petroleum gas (LPG). Different pressures and temperatures of fuel injection system were tested to identify the injection characteristics after hot soaking. MIE-scattering technique was used for verification of successful liquid phase injection after hot soaking. In case of bottom-feed type injector, the injection was accomplished at every experimental condition. In case of top-feed type injector, when the pressure of LPG was over 1.2 MPa, the injection was not executed. However, under the pressure were 1.2 MPa, the liquid phase injection after hot soaking was accomplished. The engine with top-feed type fuel injection equipment was restarted successfully after hot soaking.

The Fundamental Study on Liquid Phase LPG Injection System for Heavy-Duty Engine (II) (대형엔진용 액상분사식 LPG 연료공급방식에 대한 기초연구 (2))

  • 김창업;오승묵;강건용
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.6
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    • pp.1-7
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    • 2001
  • Recently, several LPG engines for heavy-duty vehicles have been developed, which can replace some diesel engines that are one of a main source for air pollution in urban area. As a preliminary study on the liquid phase LPG injection (hereafter LPLI) system applicable to a heavy duty LPG engine, the engine output and combustion performance were investigated with various combustion chambers and fuel compositions using a single cylinder engine equipped. Experimental results revealed that ellipse, double ellipse and nebula type combustion chamber made a more advantage in breaking swirl flow into small turbulence scale than bathtub type. Especially, performance of nebula type showed most highest efficiency and engine output under lean mixture conditions. An investigation fur various LPG fuel compositions was also carried out, and revealed that the case with 40% propane and 60% butane shows the lowest efficiency at stoichiometry, however, as the mixture became leaner its efficiency increased and became even higher for 100% propane case.

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Development of Flow Rate Model of a Liquid Phase LPG Injector (액상 LPG 인젝터의 유량 모델 개발)

  • 조성우;민경덕
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.5
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    • pp.22-28
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    • 2003
  • Flash boiling mechanism in the injector interferes with fine fuel metering in a liquid phase LPG injection engine. This study presents a mathematical model to precisely predict an injection quantity. A calibration procedure of injection quantity, which is very prompt and precise in measuring, is developed using a gas analyzer. According to this procedure, injection quantity can be obtained under various fuel compositions, temperatures and injection pressures. The release pressure of liquid phase LPG is estimated based on these experimental data. Although the release pressure is much lower than the saturation pressure, it is linearly proportional to the saturation pressure.

Performance and Emission Characteristics of Liquid-Phase LPG Injection Engine with Different EGR Rate (EGR율 변화에 대한 액상 LPG분사 엔진의 운전 및 배출가스특성)

  • 염기태;우영민;장진영;박용국;배충식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.5
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    • pp.7-14
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    • 2003
  • Exhaust Gas Recirculation (EGR) system is used to reduce NOx emission, to improve fuel economy, and to suppress knock since it offers the benefits of the inlet charge dilution. The effects of EGR was investigated on the performance and emission to reduce exhaust thermal load with a single cylinder liquid-phase LPG injection engine, in a wide range of EGR rate, engine conditions and LPG proportions. As EGR rate was increased, NOx was reduced while HC was increased. Pumping loss reduction by EGR improved bsfc and increased EGR lowered exhaust gas temperature. And, LPG proportions were made a difference on the performance and emission characteristics.

Lean Burn Characteristics in a Heavy Duty Liquid Phase LPG Injection SI Engine (대형 액상분사식 LPG 엔진의 희박연소특성에 관한 연구)

  • 오승묵;김창업;강건용;우영민;배충식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.4
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    • pp.1-11
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    • 2004
  • Combustion and fuel distribution characteristics of heavy duty engine with the liquid phase LPG injection(LPLI) were studied in a single cylinder engine, Swirl ratio were varied between 1.2, 2.3, and 3.4 following Ricardo swirl number(Rs) definition, Rs=2.3 showed the best results with lower cycle-by-cycle variation and shorter burning duration in the lean region while strong swirl(Rs=3.4) made these worse for combustion enhancement. Excessive swirl resulted in reverse effects due to high heat transfer and initial flame kernel quenching. Fuel injection timings were categorized with open valve injection(OVI) and closed valve injection(CVI). Open valve injection showed shorter combustion duration and extended lean limit. The formation of rich mixture in the spark plug vicinity was achieved by open valve injection. With higher swirl strength(Rs=3.4) and open valve injection, the cloud of fuel followed the flow direction and the radial air/fuel mixing was limited by strong swirl flow. It was expected that axial stratification was maintained with open-valve injection if the radial component of the swirling motion was stronger than the axial components. The axial fuel stratification and concentration were sensitive to fuel injection timing in case of Rs=3.4 while those were relatively independent of the injection timing in case of Rs=2.3.

LPLi Engine Performance and Vehicle Exhaust Emission Characteristics (액상 분사 LPG 엔진 성능 및 차량 배기 배출물 특성에 관한 연구)

  • 임종훈;명차리;박심수;양승주
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.4
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    • pp.15-21
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    • 2003
  • LPG is considered as one of the most prominent alternative automotive fuels in worldwide. However, conventional mixer system can not meet the emission regulations as the mileage accumulation increased. Recently, much attention is focused on the development of LPG liquid injection fuel systems to increase the engine performance and reduce the exhaust emissions. This study evaluates the LPLi(Liquid Phase LPG injection) engine performance and exhaust emission characteristics using a 3.0 liter LPG engine. The fuel supply system and engine management system were changed from FBM into LPLi to control the precise mixture ratio and optimized spark advance.

Analysis of Cylinder Swirl Flow and Lean Combustion Characteristics of 3rd Generation LPLI(Liquid Phase LPG Injection) Engine (제3세대 LPLI 엔진 연소실내 스월유동 및 희박연소 특성 해석)

  • Kang, Kern-Yong;Lee, Jin-Wook
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.1
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    • pp.26-33
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    • 2007
  • The intake swirl motion, as one of dominant effects for an engine combustion. is very effective for turbulence enhancement during the compression process in the cylinder of 2-valve engine. Because the combustion flame speed is determined by the turbulence that is mainly generated from the mean flow of the charge air motion in intake port system. This paper describes the experimental results of swirl flow and combustion characteristics by using the oil spot method and back-scattering Laser Doppler velocimeter (LDV) in 2-valve single cylinder transparent LPG engine using the liquid phase LPG injection. For this. various intake port configurations were developed by using the flow box system and swirl ratios for different intake port configurations were determined by impulse swirl meter in a steady flow rig test. And the effects of intake swirl ratio on combustion characteristics in an LPG engine were analyzed with some analysis parameters that is swirl ratio. mean flow coefficient, swirl mean velocity fuel conversion efficiency. combustion duration and cyclic variations of indicated mean effective pressure(IMEP). As these research results, we found that the intake port configuration with swirl ratio of 2.0 that has a reasonable lean combustion stability is very suitable to an $11{\ell}$ heavy-duty LPG engine with liquid phase fuel injection system. It also has a better mean flow coefficient of 0.34 to develope a stable flame kernel and to produce high performance. This research expects to clarify major factor that effects on the design of intake port efficiently with the optimized swirl ratio for the heavy duty LPG engine.

Icing Characteristics of Liquid Phase LPG Injection According to Butane and Propane Mixing Rates (부탄과 프로판 혼합비율에 따른 액상 LPG 분사시 Icing 특성)

  • Kim, Yung-Jin;Cho, Won-Joon;Lee, Ki-Hyung
    • Journal of ILASS-Korea
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    • v.16 no.3
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    • pp.146-151
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    • 2011
  • LPG(Liquified Petroleum Gas) fuel for vehicles has lots of advantages such as low emission level, cheaper fuel cost and enough infrastructure. Therefore it arouses interest as an alternative engine to reduce emission of diesel engines. Especially MPI(Multi Point Injection) type LPLi(Liquid Phase LPG injection) system could have overcome the disadvantages of mixer types such as low engine performance, decreased charging efficiency and cold starting difficulty. However ice formation on the nozzle tip and intake port due to the freezing of moisture around the components is often observed in LPLi systems. This icing phenomenon is the direct cause of unstable engine combustion, resulting in engine emissions. Therefore in this research, a spray visualization test for LPG injection was carried out to obtain the basic information of an LPLi injector, then the effects of butane and propane mixing rates on ice formation at the intake port and nozzle tip was investigated. As a result, the icing characteristics of them showed contrary results according to the mixing rates.