The purpose of this study is evaluate emission characteristics, such as nitrogen oxides (NO x ), hydrocarbon, carbon monoxide, and particulate matter (PM), of excavator with Tier-4f level diesel engine in the real work conditions. The test excavator has an engine power of 124 kW at an engine speed of 1800rpm, and it has various after-treatment devices, such as exhaust gas recirculation (EGR), selective catalytic reduction (SCR), and diesel oxidation catalyst (DOC), to reduce the engine-out emissions. The emissions including carbon monoxide (CO), carbon dioxides (CO 2 ), and NO x , were measured by portable emission measurement system (PEMS). The PEMS device conducted a correlation analysis with the emission bench on the engine dynamometer before being used to measure the real-work to confirm the reliability of the equipment. The tests were carried out in four categories: idling, driving, excavations and flattening. It revealed that the average power output for each operation mode was higher in the order of flattening, excavation, and drive. On average, those are higher than that for the non-road transient cycle (NRTC) certification mode as 1.5 to 1.9 times. It may be determined that the power output is higher in conditions where there are more boom and bucket movements than the movement of the vehicle itself. In emission analysis, NOx and HC emission in driving mode are higher than other two modes: excavation and flattening. The real time NO x have been low in most test conditions, but large quantities of NO x have been released due to the deactivation of the SCR catalyst during cold start period or immediately after the non-working.

Numerical study on the combustion chemical reaction of biodiesel fuel for the improvement of compression ignition combustion performance was studied in this work. The constant volume closed homogeneous reactor model was applied, at the same time, analysis conditions were set to 700∼900K of ambient temperature, and 15atm of ambient pressure. Also, the equivalence ratio was changed from 0.5 to 1.4 under the various mixing ratio, respectively. The results of analysis were compared in terms of ignition delay, combustion temperature, combustion pressure, NOx and CO emissions. Also, the total mass and the mass densities of the reactants were compared in the constant volume chamber. It was revealed that the value of ignition delay became shorter and combustion temperature and pressure were increased under the rich combustion conditions (Φ > 1.0). Furthermore, the CO emission was decreased under the lean combustion conditions (1.0 > Φ). Maximum value of NOx emission was observed when the equivalence ratio was 0.8 condition since the nitrogen and oxygen chemical reactions became actively than other cases.

The objective of this study is to investigate the effect of water injection into intake port on the performance of small CI engine. The ECFM-3Z model was applied for the combustion analysis model, and the amount of injected water were varied 10%, 20% and 30% of injected fuel mass. The results of this work were compared in terms of cylinder pressure, rate of heat release (ROHR), and the ISNO and soot emissions. It was found that the cylinder pressure was decreased from 1.2% to 9.2% when the amount of injected water was increased from 10% to 30%. In the results, NO emission significantly decreased from about 24% to about 85% when the amount of injected water increased due to the specific heat and latent heat of water. Considering the test results, the best conditions for the simultaneous reduction of NO and soot is the BTDC 05deg of injection timing and 30% of water injection mass. It can be expected the best IMEP and ISFC characteristics.

An experimental investigation was performed on the effect of injection strategy on the combustion, exhaust emissions characteristics and the particle size distribution in a direct-injection (DI) compression ignition engine fueled with biodiesel-ethanol blended fuel. The results obtained from the experiment of the particle distributions for the blended fuel are compared to that of diesel fuel. In addition to the distribution of the particles, exhaust emissions such as oxides of nitrogen (NO x ), hydrocarbon (HC), and carbon monoxide (CO) emissions and combustion characteristics under different engine operating parameters were investigated. The engine operating parameters in terms of injection timing and injection strategy were varied to investigate the combustion and emission reduction of biodiesel and ethanol blended fuel. The results show that multiple injection strategy of biodiesel-ethanol blended is beneficial to reduce NO x emissions significantly without significant increase of soot emission. In multiple injection strategy, as the first injection mass was increased, the larger size particles were increased, however total numbers of particles were reduced. Biodiesel-ethanol blended fuel reduced particle concentration of relatively large size compared to the particles concentration of ULSD. Moreover, dramatically lower NO x and soot emissions were found at the blend fueled with engine at the same injection condition.

An experiment was performed to analyze the effects of biodiesel-ethanol blended fuel spray on the combustion and exhaust emission characteristics of a single-cylinder common-rail diesel engine. To analyze the macroscopic and microscopic characteristics of biodiesel blended fuel spray, measurements of the injection rate, droplet diameter, and spray tip penetration were taken using an injection rate meter, spray visualization and a droplet measuring system. The combustion, exhaust emission characteristics and size distributions of particulate matter were determined for various engine operating conditions using biodiesel-ethanol blends, and the results were compared to those of conventional diesel fuel. In this investigation, the measured results of biodiesel-ethanol blended fuels show that the Sauter mean diameter (SMD) decreased with an increase of relative velocity between the injected fuel and ambient gas. Comparing the combustion characteristics of diesel fuel and biodiesel-ethanol blended fuels, both diesel and blended fuel showed similar trends in combustion pressure and the rate of heat release. However, the combustion of biodiesel-ethanol blends had lower combustion characteristics such as combustion pressures and heat release rates than those of diesel fuel because of their lower heating values. In the case of exhaust gas recirculation (EGR), the indicated specific NO x (ISNO x ), and soot concentrations were lower than those of conventional diesel fuel.

The aim of this work is to investigate the effect of mixing ratio and pilot injection on spray and combustion characteristics of biodiesel fuel and compared with those of diesel fuel in a direct injection common-rail diesel engine. In order to study the influence factors of biodiesel fuel on the spray and combustion characteristics, the experiments were conducted at various mixing ratios and injection conditions of the biodiesel and engine operating conditions. The macroscopic and microscopic characteristics such as injection rate, split injection effect, spray tip penetration, droplet diameter, and axial velocity distribution of biodiesel fuel were compared with the results of conventional diesel fuel by using spray visualization system composed of Ar-ion laser, ICCD camera and phase Doppler particle analyzer (PDPA) system. The combustion and exhaust emission characteristics of biodiesel fuel were studies using common-rail diesel engine with four cylinders. For the biodiesel blended fuel, it was revealed that higher injection pressure is needed to achieve the same injection rate at the higher mixing ratio. The spray tip penetration of biodiesel fuel was much the same with those of diesel. The atomization characteristics of biodiesel were inferior to conventional diesel fuel due to high viscosity and surface tension. The peak combustion pressures of both fuels were increased with advanced injection timing and the combustion pressure of biodiesel fuel is higher than that of diesel fuel. As the pilot injection timing is advanced to the TDC, the dissimilarities of both fuels combustion pressure are reduced. It can be also founded that the pilot injection can enhance the deteriorated spray and combustion characteristics of biodiesel fuel caused by physical fuel properties.

The purpose of this study is to investigate the effect of injection parameters on the injection and spray characteristics of dimethyl ether and diesel fuel. In order to analyze the injection and spray characteristics of dimethyl ether and diesel fuel with employing high-pressure common-rail injection system, the injection characteristics such as injection delay, injection duration, and injection rate, spray cone angle and spray tip penetration was investigated by using the injection rate measuring system and the spray visualization system. In this work, the experiments of injection rate and spray visualization are performed at various injection parameters. It was found that injection quantity was decreased with the increase of injection pressure at the same energizing duration and injection pressure In the case of injection characteristics, dimethyl ether showed shorter of injection delay, longer injection duration and lower injected mass flow rate than diesel fuel in accordance with various energizing durations and injection pressures. Also, spray development of dimethyl ether had larger spray cone angle than that of diesel fuel at various injection pressures. Spray tip penetration was almost same development and tendency regardless of injection angles.