• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.7 s.250
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• pp.682-691
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• 2006

This study was conducted to assess the effect of mixed fuel composition and mass fraction on spray inner structure in evaporating transient spray under the various ambient conditions. Spray structure and spatial distribution of liquid phase concentration are investigated using a thin laser sheet illumination technique on the multi-component mixed fuels. A pulsed Ar+ laser was used as a light source. The experiments were conducted in a constant volume vessel with optical access. Fuel was injected into the vessel with electronically controlled common rail injector. Used fuel contain $i-octane(C_8H_{18}),\;n-dodecane(C_{12}H_{26})$ and $n-hexadecane(C_{16}H_{34})$ that are selected as low-, middle- and high-boiling point fuel, respectively. Experimental conditions are 25Mpa, 42MPa, 72MPa and 112MPa in injection pressure, $5kg/m^3,\;15kg/m^3\;and\;20kg/m^3$ in ambient gas density, 400K, 500K, 600K and 700K in ambient gas temperature, 300K and 368K in fuel temperature, and different fuel mass fraction. Experimental results indicate that the more high-boiling point component, the longer the liquid phase it were closely related to fuel physical properties, but injection pressure had no effect on. And there was a high correlation between the liquid phase length and boiling temperature at 75% distillation point.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.58-64
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• 2003

Dimethyl Ether(DME) has been considered as one of the most attractive alternative fuels for compression ignition engine. Its main advantage in diesel engine application is high efficiency of diesel cycle with soot free combustion though conventional fuel injection system has to be modified due to the physical properties of DME. Experimental study of DME and conventional diesel spray employing a common-rail type fuel injection system with a 5-hole sac type injector was performed in a constant volume vessel pressurized by nitrogen gas. Spray cone angles and penetrations of the DME spray were characterized and compared with those of diesel. For evaluation of the evaporating characteristics of the DME, shadowgraphy technique employing an Ar-ion laser and an ICCD camera was adopted. Tip of the DME spray was formed in mushroom-like shape at atmospheric chamber pressure, which disappeared in higher chamber pressure. Spray tip penetration and spray cone angle of the DME became similar to those of diesel under 3MPa of chamber pressure. Higher injection pressure provided wider vapor phase area while it decreased with higher chamber pressure condition.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.2
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• pp.203-210
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• 2015

This paper investigates the failure of a car with a 2.5-liter CRDi engine of the Hyundai Company. The failure is caused by intermittent poor acceleration while driving. To analyze the cause, we investigated the air intake volume, the fuel injection, and the air-fuel ratio, which were determined to be normal. The brake switch signal error was discovered while analyzing the function that limits the output of the engine. While investigating the cause, we discovered the corrosion of the pins on the connector of the brake switch. We determined that it was generated by soapy water flowing in the solar film. Therefore, the cause of the failure was the brake switch signal errors. Additionally, we determined that ECM was the normal fail-safe mode that implemented the override device for safety during normal acceleration. Based on these results, further solar film experiments must be conducted to fully elucidate the causes.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.5
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• pp.172-180
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• 2006

This study was to analyze the effect of mixed fuel composition and mass fraction on the characteristics of evaporating diesel spray and combustion under the various ambient conditions. The characteristics of vaporization distribution and combustion were visualized by laser induced fluorescent method and direct photography. The experiments were conducted in the constant volume vessel and rapid compression expansion machine with optical access. Multi-component fuels mixed i-octane, n-dodecane and n-hexadecane were injected the vessel and rapid compression expansion machine with electronically controlled common rail injector. Experimental results show that fuel vapor formed stratified distribution. And vaporization and diffusion are become actively increasing in mass fraction of low boiling point component. Consequently multi-component fuels were expected to control the evaporating behavior according to their suitable mass fraction.

• Journal of ILASS-Korea
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• v.5 no.4
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• pp.33-39
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• 2000

The behavior of the 2-stage spray was studied by using the schlieren method with the high pressure common-rail injection system. The spray injected 2 times with the interval of $0.3ms{\sim}1.5ms$ between the 1st and the 2nd spray in a modeled combustion chamber of constant volume bomb. In this case, the quantity of injected fuel of 1st and 2nd also changed. The schlieren photograph shows that the 2nd spray goes further away than the 1st spray when the quantity of the 1st spray is less than that of the 2nd spray. The dispersion of the vapour to the combustion chamber is not affect in a 10% of 1st spray quantity. When the 1st spray quantity is more than the 2nd spray, the vapour scattering of spray is good.

• Journal of Power System Engineering
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• v.9 no.4
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• pp.214-219
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• 2005

The effects of change in injection pressure on spray structure in high temperature and pressure field have been investigated. The analysis of liquid and vapor phases of injected fuel is important for emissions control of diesel engines. Therefore, this work examines the evaporating spray structure using a constant volume vessel. The injection pressure is selected as the experimental parameter, is changed from 72MPa to 112MPa by using a common rail injection system(ECD-U2). The images of liquid and vapor phase in the evaporating free diesel spray are simultaneously taken by exciplex fluorescence method. As a result, it can be confirmed that the distribution of vapor concentration is more uniform in the case of the high injection than in that of the low injection pressure.

• Journal of Korean Society of Forest Science
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• v.94 no.3 s.160
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• pp.135-145
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• 2005

The purpose of this study is to reveal the component characteristics and the channels of distribution for forest products as a fuel that were consumed in Kyeongseong city (Seoul) in 1929, in the middle of the colonial period. The summary of the results are as follows; (1) though the average consumption of forest products consumed as a fuel per household in Kyeongseong city was slightly less than one-third as much forest products as fuel consumed in other counties of Kyeongki province, but due to the high heat capacity, the amount of fuelwood and charcoal consumption was much higher than leaf and grass consumption; (2) the largest supply areas of forest products for fuel were the riverside of Kangwon province and Kyeonggi province in which the waterways were available. They supplied 42.6% of total consumption, and the other supply areas were the northern part of Kyeonggi province, etc. (29.5%) where railroads were handy, and the suburbs of Kyeongseong City (27.9%) by roads; (3) the transportation areas using the Han River were divided into two parts of Ttook island (43.0%) and former Yongsan and Mapo (45.6%), but the volume of transportation by railroad was centralized in Kyeongseong Station, which accounted for 72.2% of total volume of transportation by rail; (4) the most of the forest products consumed for fuel in Kyeongseoung city were sold in temporary fuelwood markets, rather than permanent and regular markets.

• Journal of Energy Engineering
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• v.24 no.1
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• pp.132-136
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• 2015

The objective of this study is to investigate the effect of biodiesel blending on spray and combustion characteristics. In order to this, blended fuels containing 0, 5, 20, 50, 100% biodiesel in weight fraction was injected via common rail to constant volume combustion chamber. As a result, spray cone angle decreased and the Sauter mean diameter increased because of the higher dynamic viscosity and density of biodiesel, however, it does not seemed that spray penetration was affected by these factors considerably. In the combustion experiment, ignition delay of biodiesel was shorter than that of diesel due to higher cetane number. And the peak value of heat release rate increased and the end of combustion was advanced owing to higher combustion efficiency cause by the characteristic of oxygenated fuel.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.911-917
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• 2015

The objective of this work focuses on the analysis of injection rate and macroscopic spray behavior characteristics with injection pressures as well as combustion and exhaust emission characteristics with injection timing and injection pressure by using a common rail single-cylinder diesel engine. The injection rate was measured by applying the Bosch method, and macroscopic spray behavior characteristics were analyzed with a constant-volume vessel and a high-speed camera. In addition, combustion and emission characteristics were analyzed in a common-rail single-cylinder diesel engine with precise control of fuel injection timing and pressure. For injection pressures of 30MPa and 50MPa, the injection rate was higher at 50 MPa, and the spray development (penetration) was also higher in the same elapsed time. The peak in-cylinder pressure and rate of heat release showed a tendency to decline as injection timing was delayed, and the peak in-cylinder pressure and rate of heat release were slightly higher for higher injection pressures. Higher injection pressures also reduced the mean effective pressure, while the indicated mean effective pressure and torque increased as injection timing was delayed to TDC. Nitrogen oxides had a peak level at injection timings of $BTDC20^{\circ}$(30MPa) and $BTDC15^{\circ}$(50MPa); carbon monoxide emissions were reduced by delaying injection timing from $BTDC30^{\circ}$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.2 s.257
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• pp.188-194
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• 2007

New diesel engines equipped with common-rail injection systems and advanced engine management control allow drastic decreases in the production of particulate matters and nitrogen oxides with a significant advantage in terms of the fuel consumption and $CO_2$ emissions. Nevertheless, the contribution of exhaust gas after treatment in the ultra low emission vehicles conception has become unavoidable today. Recently the passive type DPF(Diesel Particulate Filter Trap) system for diesel passenger vehicle has been manufactured into mass production from a French automotive maker since the year of 2000. This passive DPF system fully relies on the catalytic effects from additives blended into the diesel fuel and additives injected into the DPF system. In this study, the effects of PM regeneration in the commercial diesel passenger vehicle with the passive type DPF system were investigated in chassis dynamometer CVS(constant volume sampler)-75 mode. As shown in this experimental results, the DPF regeneration was observed at temperature as low as $350^{\circ}C$. And the engine-controlled the DPF regeneration founded to be one of the most promising regeneration technologies. Moreover, the durability of this DPF system was evaluated with a season weather in terms of the differential pressure and exhaust gas temperature traces from a road test during the total mileage of 80,000km.