• 대한기계학회논문집B
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• 제29권3호
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• pp.417-423
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• 2005

This paper describes the engine performance of a Homogeneous Charge Compression Ignition(HCCI) engine according to Exhaust Gas Recirculation(EGR), cylinder-to-cylinder, fuel of propane and butane. HCCI engines are being considered as a future alternative for diesel and gasoline engines. HCCI engines have the potential for high efficiency, very low NOx emissions and very low particulate matter(PM). On experimental work, we have done an evaluation of operating conditions in a 4-cylinder compression engine. The engine has been run with propane and butane fuels at a constant speed of 1800rpm. This work is intended to investigate the HCCI operation of the engine in this configuration that has been modified from the base diesel engine. The performance and emissions of the engine are presented. In this paper, the start of combustion(SOC) is defined as the $50{\%}$ point of the peak rate of heat release. SOC is delayed slightly with increasing EGR. As expected, NOx emissions were very low for all EGR range and nbuned HC and CO emission levels were high. CO and HC emissions are lower with using propane than butane as fuels of HCCI engines.

• 한국수소및신에너지학회논문집
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• 제28권2호
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• pp.225-230
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• 2017

Coal oil is widely used as a home heating fuel for portable and installed coal oil heaters. Today, Coal oil is widely used as fuel for jet engines and some rocket engines in several grades. This paper describes the performance characteristics according to the compression ratio of spark ignition engine fuelled with coal oil. As a result, the following knowledge is obtained: As the compression ratio is decreased, there is an increase in torque, indicated mean effective pressure (IMEP), heat release rate, and brake thermal efficiency. Higher compression ratio of the engine decreases the ignition delay period, combustion period, and cooling loss.

• 한국연소학회:학술대회논문집
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• 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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• pp.13-19
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• 2003

As the environmental pollution becomes serious global problem, the regulation of emission exhausted from automobiles is strengthen. Therefore, it is very important to know how to reduce the NOx and PM simultaneously in diesel engines, which has lot of merits such as high thermal efficiency, low fuel consumption and durability. By this reason, the new concept called as Homogeneous Charge Compression Ignition(HCCI) engines are spotlighted because this concept reduced NOx and P.M. simultaneously. However, it is well known that HCCI engines increased HC and CO. Thus, the investigation of combustion characteristics which consists cool and hot flames for HCCI engines were needed to obtain the optimal combustion condition. In this study, combustion characteristics for direct inject type HCCI engine such as quantity of cool flame and hot flame, ignition timing and ignition delay were investigated to clarify the effects of these parameters on performance. The results revealed that diesel combustion showed the two-stage ignition of cool flame and hot flame, the rate of cool flame increase and hot flame decrease with increasing intake air temperature. On the other hand, the gasoline combustion is the single-stage ignition and ignition timing is near the TDC. In addition mixed fuel combustion showed different phenomenon, which depends on the ratio of gasoline component. Ignition timing of mixed fuel is retarded near the TDC and the ignition delay is increased according to ratio of gasoline.

• 한국연소학회지
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• 제16권1호
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• pp.52-57
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• 2011

The present study describes the characteristics of combustion and exhaust emissions in compression ignition engines using diesel-gasoline dual fuel. For investigating combustion characteristics, diesel fuel was injected directly in a single-cylinder compression ignition engine with a common-rail injection system and gasoline fuel was injected into a premixed chamber installed in an intake port. In order to investigate exhaust emission characteristics, exhaust gas was measured by emission analyzer and smoke meter. The experimental results showed that cases of diesel-gasoline dual fuel combustion exhibited extended ignition delay and reduced peak combustion pressure compared to those of directly injected diesel fuel cases. Furthermore, premixed gasoline-air mixture reduced NOx emissions due to low peak of rate of heat release(ROHR).

• 한국자동차공학회논문집
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• 제12권2호
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• pp.83-90
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• 2004

A flywheel-driven rapid compression and expansion machine is developed and utilized for experimental study of homogeneous charge compression ignition combustion. Compression ignition of homogeneous charge in IC engines offers possibilities of realizing ultra-lean engine operation with greatly reduced NOx and particulate formation. Fundamental investigations are carried out in order to better understand this ideal engine combustion mechanism. Perfectly premixed propane-air mixtures of various equivalence ratio are compression-ignited in the rapid compression and expansion machine, and the characteristics of the auto-ignition and the following combustion process are analyzed.

• Journal of Mechanical Science and Technology
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• 제20권9호
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• pp.1449-1458
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• 2006

Controlled Auto-ignition (CAI) combustion processes can be broadly divided between a CAI process that is applied to four-cycle engines and a CAI process that is applied to two-cycle engines. The former process is generally referred to as Homogeneous Charge Compression Ignition (HCCI) combustion and the later process as Active Thermo-Atmosphere Combustion (ATAC) The region of stable engine operation differs greatly between these two processes, and it is thought that the elucidation of their differences and similarities could provide useful information for expanding the operation region of HCCI combustion. In this research, the same two-cycle engine was operated under both the ATAC and HCCI combustion processes to compare their respective combustion characteristics. The results indicated that the ignition timing was less likely to change in the ATAC process in relation to changes in the fuel octane number than it was in the HCCI combustion process.

• 한국자동차공학회논문집
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• 제4권2호
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• pp.147-157
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• 1996

Natural gas is gaining more attraction as a future fuel in particular both for environmental protection and energy conservation. In order to bring about more widespread use of gaseous engines, the technology capable of achieving output and efficiency performance equivalent to that of diesel engines needs to be developed. In the present paper, the requirements of the pilot torch from pre-chamber for ensuring ignition and promoting combustion are discussed by means of taking high-speed flame photography and system can run with leaner mixture of various fuels comparing to the electric plug ignition system cause the ignition delay period ignited with the torch and the combustion period are very short in spite of changing A/F of gaseous fuels in the main chamber. However, the suitable piston-cavity design for the use of lower-hydrocarbon fuels such as propane and butane must be discussed increasingly in the mear future.

• 한국수소및신에너지학회논문집
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• 제27권5호
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• pp.604-611
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• 2016

This paper describes the characteristics of n-Butane fuel for the homogeneous charge compression ignition (HCCI) engine for a new concept. HCCI engines are being considered as a future alternative for diesel and gasoline engines. From the experimental observations, the effect of n-Butane fuel in HCCI engine on CO, HC and NOx are analysed. The objective of this paper is to clear the effects of equivalence ratio and inlet temperature with n-Butane on the HCCI. For this purpose, a 4-cylinder, compression ignition engine was converted into a HCCI engine This work has been run with n-butane fuel at a constant speed.

• 한국분무공학회지
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• 제28권2호
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• pp.55-61
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• 2023

Natural gas is a high-octane fuel that is effective in controlling knocking combustion. In addition, as a low-carbon fuel with a high hydrogen-carbon ratio, it emits less carbon dioxide and almost no particulate matter compared to conventional fossil fuels. Stoichiometric combustion engines equipped with a three-way catalyst are useful in various fields such as transportation and power generation because of their excellent exhaust emission reduction performance. However, stoichiometric combustion engines have a disadvantage of lower thermal efficiency compared to lean combustion engines. In this study, a combination of high compression ratio and Atkinson cycle was implemented in a 11 liter, 6-cylinder, spark-ignition engine to improve the thermal efficiency of the stoichiometric engine. As a result, pumping and friction losses were reduced and the operating range was extended with optimized Atkinson camshaft. Based on the exhaust gas limit temperature of 730℃, the maximum load and thermal efficiency were improved to BMEP 0.66 MPa and BTE 35.7% respectively.

• 한국자동차공학회논문집
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• 제14권3호
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• pp.1-9
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• 2006

Recently, there has been an interest in premixed diesel engines as it has the potential of achieving a more homogeneous and leaner mixture close to TDC compared to conventional diesel engines. Because this concept reduced NOx and smoke emissions simultaneously. Early studies are shown that in a HCCI(Homogeneous Charge Compression Ignition) engine, the fuel injection timing and intake air temperature affect the mixture formation. The purpose of this study is to investigate characteristics of combustion and mixture formation according to injection timing and intake air temperature in a common rail direct injection type HCCI engine using an early injection method called the PCCI(Premixed Charge Compression Ignition). From this study, we found that the fuel injection timing and intake air temperature affect the mixture formation and in turn affects combustion in the PCCI engine.