• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.1-9
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• 2014

The vast stores of biomass available in the worldwide have the potential to displace significant amounts of petroleum fuels. Fast pyrolysis of biomass is one of several paths by which we can convert biomass to higher value products. The wood pyrolysis oil (WPO) has been regarded as an alternative fuel for petroleum fuels to be used in diesel engine. However, the use of WPO in a diesel engine requires modifications due to low energy density, high water contents, high acidity, high viscosity, and low cetane number of the WPO. One possible method by which the shortcomings may be circumvented is to co-fire WPO with other petroleum fuels. WPO has poor miscibility with light petroleum fuel oils; the most suitable candidates fuels for direct fuel mixing are methanol or ethanol. Early mixing with methanol or ethanol has the added benefit of significantly improving the storage and handling properties of the WPO. For separate injection co-firing, a WPO-ethanol blended fuel can be fired through diesel pilot injection in a dual-injection dieel engine. In this study, the performance and emission characteristics of a dual-injection diesel engine fuelled with diesel (pilot injection) and WPO-ethanol blend (main injection) were experimentally investigated. Results showed that although stable engine operation was possible with separate injection co-firing, the fuel conversion efficiency was slightly decreased due to high water contents of WPO compare to diesel combustion.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.4
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• pp.76-82
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• 2007

This paper described the effect of the multiple injections on the stability of combustion and emission characteristics in a direct injection diesel engine at various operating conditions. In order to investigate the influence of multiple injections in a diesel engine, the fuel injection timing was varied one main injection and two pilot injections at various conditions. The experimental apparatus consisted of DI diesel engine with four cylinders, EC dynamometer, multi-stage injection control system, and exhaust emissions analyzer. The combustion and emission characteristics were analyzed for the main, pilot-main injection, pilot-pilot-main injection strategies. It is revealed that the combustion pressure was smoothly near the top dead center and the coefficient of variations is reduced due to the effect of pilot injection. Also, $NO_x$ emissions are dramatically decreased with pilot injection because the decrease of rate of heat release. However, the soot is increased at early pilot injection and main injection.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.89-95
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• 2001

Recently GDI(Gasoline Direct Injection) engine is spotlighted to achieve higher thermal efficiency under partial loads and better performance at full loads. To realize this system, it is essential to make both stratified combustion and homogeneous combustion. When compared to PFI(Port Fuel Injection) engine, GDI engine needs more complicated control and optimal design with injection system. In addition, spray pattern must be optimized according to injection timing because ambient pressure in combustion chamber is also varied. Thus spray structure should be analyzed in details to meet various conditions. In this experimental study, two types of visualization system were developed to simulate compression stroke and intake stroke, respectively. With an increase of the ambient pressure, the penetration length tends to decrease due to rising resistance caused by the drag force of the ambient air. Spray characteristics impinged on the piston has a significant effect on mixture stratification around the spark plug. These results provide the information on macroscopic spray structure and design factors far developing GDI injector.

• The Journal of the Acoustical Society of Korea
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• v.37 no.4
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• pp.242-247
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• 2018

The automotive industry is making various efforts to cope with ever-increasing exhaust emissions and fuel economy regulations. However, this often results in degraded NVH (Noise, Vibration, and Harshness) performance. For example, we proposed the causes and improvements for the noise generated by the high-pressure pump noise of a gasoline engine, the change of acceleration noise due to dual injection of MPI (Multi-Point Injection) and GDI (Gasoline Direct Injection), the noise of a gasoline turbocharger, and the combustion noise deteriorated due to the injection parameters calibration in a diesel engine. Since these noises are caused by the high frequency noise, and the driver feels the rough sound quality, efforts to reduce them with proper NVH measures are indispensable.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.24-30
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• 2004

As the environmental pollution becomes serious global problem, the regulation of emission exhausted from automobiles is strengthened. 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, there is trade off between output and NOx in a HCCI engine. In this study, output and emission characteristics for a gasoline direct injection type HCCI engine were investigated to clarify the effects of intake air temperature, injection time and mixture formation. From these experiments, we found that the smoke was not produced when the fuel was injected earlier than BTDC 90$^{\circ}$. In addition, the output was increased because of delay of ignition time and NOx emission was decreased because of homogeneous charge of first injection in case of split injection.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.1
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• pp.27-35
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• 1998

This study describes the influence of combustion parameters on the nitric oxide emission, such as injection timing, air flow rate, injected amount of fuel, and compression ratio of engine. In order to determine the influence factors on the nitric oxide emission, the experiment were investigated with various parameters of engine cycle. According to the results of this study, the retardation of injection timing and the increases of airflow rate, and the decreases of fuel injection amount reduce the nitric oxide concentration in the exhaust emissions. Also, the increases of compression ration of engine increase in the concentration of nitric oxide formation in the combustion chamber. The results of this study give a guideline to decrease the nitric oxide formation by using the simulation program.

• Journal of the korean Society of Automotive Engineers
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• v.7 no.1
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• pp.35-42
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• 1985

This paper describes an experimental study of the effect of injection timing on the combustion characteristics in four stroke cycle diesel engine with direct injection type combustion chamber. The effect of injection timing and compression ratio of engine on the combustion characteristics are investigated. Experimental results of combustion characteristics in cylinder show that the combustion pressure and the rate of pressure rise decrease in accordance with the retard of fuel injection timing. It is observed that the rate of pressure rise in cylinder is increased an increase in the compression ratio of engine. The effect of the fuel injection timing on the frequency of cylinder pressure brings about the same trend of the maximum rate of pressure rise in cylinder.

• International Journal of Automotive Technology
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• v.2 no.4
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• pp.123-133
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• 2001

An important goal in diesel engine research is the development of a means to reduce the emission of oxides of nitrogen ($NO_x$) and soot particulate. A phenomenological model based on the multizone concept is used in the current paper to analyze and compare the effects of exhaust gas recirculation (EGR) and split fuel injection on emission from a compression-ignited, direct-injection engine. The present results show that $NO_x$ can be reduced with a minimum penalty of soot particle emission with cooled EGR. Compared with EGR, split fuel injection has a higher soot penalty at a given level of $NO_x$ reduction.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.51-58
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• 2004

Optimization of engine desist and operation parameters using a genetic algorithm was demonstrated for direct injection diesel engine combustion. A micro genetic algorithm and a modified KIVA-3V code were used for the analysis and optimization of the engine combustion. At each generation of the optimization step the micro genetic algorithm generated five groups of parameter sets, and the five cases of KIVA-3V analysis were to be performed either in series or in parallel. The micro genetic algorithm code was also parallelized by using MPI programming, and a multi-CPU parallel supercomputer was used to speed up the optimization process by four times. An example case for a fixed engine speed was performed with six parameters of intake swirl ratio, compression ratio, fuel injection included angle, injector hole number, SOI, and injection duration. A simultaneous optimization technique for the whole range of engine speeds would be suggested for further studies.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.2
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• pp.45-51
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• 2018

Compression ignition diesel engine can reduce carbon emission than gasoline engine in case of high efficiency, output and durability. So, compression ignition diesel engine is used in various fields such as automobiles, industries and so on. Due to reducing of emission exhaust by Developing of injection and combustion type of diesel engine, emission of pollution substance is developed compared the past. Moreover, its efficiency and reduce of carbon emission is better than gasoline engine and it is used in power source of industries, transports and others because of its high efficiency and durability nowadays. In this study, we experiment by making and designing of compression ignition diesel engine witch has air-cooling, 2 cylinder and 2 strokes.