Combustion and Emissions of Gasoline Compression Ignition Engine Fuelled with Gasoline-Biodiesel Blends

A gasoline compression ignition (GCI) engine was proposed to be the next generation internal combustion engine for gasoline. The effect of exhaust gas recirculation (EGR) and intake boosting on combustion and emissions of GCI engine fueled with gasoline-biodiesel blends by partially premixed compression ignition (PPCI) combustions are investigated in this study. Tests were conducted on a single-cylinder direct-injection CI engine, with 5% by volume proportion of biodiesel in gasoline fuel blends. Engine control parameters (EGR rate, intake boosting rate, and various injection strategies) were adjusted to investigate their influences on combustion and emissions of this GCI engine. It is found that changes in EGR rate, intake boosting pressure and injection strategies affect on ignition delay, maximum pressure rise rate and thermal efficiency which is closely tied to HC, CO, NOx and smoke emissions, respectively

Comparative Life Cycle Assessment of Liquefied Natural Gas and Marine Fuel for Ship from Well to Hull

In this study, well-to-hull was obtained by life cycle assessment (LCA) and GREET, which is developed by Argonne National Laboratory to evaluate the environmental impact of marine LNG and marine fuel. This study compared the environmental impact of marine LNG and marine fuels, which were caused by green house gases (GHGs) emissions and energy consumption. The effect resulted from well-to-pump (WTP) process and pump to hull (PTH). Natural gas has the potential to generate more greenhouse gases than liquid fuels due to the amounts of leaks of the gas that were sent out of the air during production and processing. Nevertheless, the results showed that the greenhouse gases produced during transportation were enough to reduce the disadvantages (pump-to-hull process). The research expects that the results will be under the environmental policy of South Korea

Thermal Efficiency and Emission Characteristics of a Diesel-hydrogen Dual Fuel CI Engine at Various Loads Condition

Efforts to find alternative fuels and reduce emissions of CI engines have been conducted, one of which is the use of diesel hydrogen dual fuel. One of the goals of using hydrogen in dual-fuel combustion systems is to reduce particulate emissions and increase engine power. This study investigates the thermal efficiency and emission characteristics of a diesel-hydrogen dual fuel CI engine at various loads condition. The hydrogen was used as a secondary fuel in a single cylinder 667 cm3 diesel engine. The hydrogen was supplied to intake manifold by fumigation method, and diesel was injected directly into the combustion chamber. The results show that the performance test yielding an increase around 10% in the value of thermal efficiency of diesel engines with the addition of hydrogen either at 2000 or 2500 rpm. Meanwhile, emission analyses show that the addition of hydrogen at 2000 and 2500 rpm lead to the decrease of NOx value up to 43%. Furthermore, the smokeless emissions around 0% per kWh were occurred by hydrogen addition at 2000 and 2500 rpm of engine speeds with load operation under 20 Nm

Macroscopic Spray Behavior of a Single-Hole Common Rail Diesel Injector Using Gasoline-Blended 5% Biodiesel

This research studies the macroscopic spray structure from a single-hole common rail diesel injector using gasoline-blended 5% biodiesel for use in compression ignition engines. To reduce the NOX/PM trade-off emissions, researchers are investigating gasoline used in compression ignition engines, called gasoline compression ignition. As a result that gasoline is injected directly into the combustion chamber, its spray field has a significant effect on combustion and emissions. Due to its low lubricity, gasoline is blended with biodiesel 5%, as a lubricity enhancer, to prevent the failure of the high-pressure injection system. The macroscopic spray structures of this gasoline blend were investigated Schlieren photography and planar laser-induced fluorescence-particle image velocimetry. Injection pressure was handled by a conventional common rail system, while ambient pressure was controlled by supplying nitrogen into the constant-volume combustion chamber. The effects of injection pressure and ambient pressure on the gasoline spray elucidated by Planar laser-induced fluorescence coupled with particle-image velocimetry (PLIF-PIV) imagery and comparisons with variations in neat diesel spray. In addition, the flow field of gasoline spray that formed vortexes and vorticity was characterized. The results show that the injection pressure and back pressure had the same effects on the gasoline spray structure, in terms of the penetration tip and cone angle, as on the diesel spray. However, the injection pressure had a greater effect on the diesel spray than the gasoline at low ambient pressure due to the occurrence of cavitation. Moreover, the images show the remarkable turbulent structure of gasoline spray and indicate air entrainment at the spray tip region

Effects of Design Parameters on Operating Characteristics of an Electric Assisted Bicycle Using Fuel Cell

A simulation study was conducted to examine the effects of design parameters on the operation of an electric power-assisted bicycle using fuel cell. Bicycle dynamic, electric motor and fuel cell models were built to depict operation of the electric bicycle. These models were solved by Matlab-Simulink to obtain the operating characteristics of the electric bicycle, such as power of fuel cell, propulsion force, moving distance and velocity. The simulation results in motion were compared to experimental results to validate the simulation models. The effects of the number of cells and hydrogen fuel pressure on the operation of the electric bicycle were investigated. In addition, the influences of slope grade on the operating characteristics of the electric-assisted bicycle and fuel cell were investigated in two cases: without and with fuel cell control. The simulation results show that the operating performance of the electric bicycle was improved when the number of cells was increased. The increase in hydrogen fuel pressure helped to increase the operating performance of the electric bicycle; however, this contribution was not significant. When fuel cell control was applied, the velocity of the electric assisted bicycle could be maintained at a stable value, in spite of changing slope grade

Development of a High-Performance Electric Pressure Regulator Applied for Compressed-Natural-Gas-Fueled Vehicles

A model-based study is carried out based on a combination of mathematical and Maxwell models to develop a high-performance electric pressure regulator utilized for compressed-natural-gas-fueled vehicles. To reduce computational cost, a symmetric two-direction model of the electric pressure regulator is established in Maxwell software, in which its material properties and dimension parameters are obtained on the base of specifications of a real electric pressure regulator. The output of simulating in Maxwell is the electromagnetic force, which is significantly improved when changing core shape in the various dimensions ∆1, ∆2, and ∆3. The optimal electromagnetic force is utilized for the mathematical models as an input variable to simulate the operational characteristics of the electric pressure regulator such as displacement and response time of plunger. The operational characteristics of the electric pressure regulator are examined under the influences of key parameters, including inlet gas pressure, diameter of orifice, and spring stiffness. By optimizing these key parameters, the simulated results in this study show that an electric pressure regulator with high performance can be obtained

A Review of Gasoline Compression Ignition: A Promising Technology Potentially Fueled with Mixtures of Gasoline and Biodiesel to Meet Future Engine Efficiency and Emission Targets

Efforts have been made to develop efficient and alternative powertrains for internal combustion engines including combustion at low-temperature (LTC) concepts. LTC has been widely studied as a novel combustion mode that offers the possibility to minimize both nitrogen oxide (NOx) and particulate matter (PM) via enhanced air-fuel mixing and intake charge dilution, resulting in lower peak combustion temperatures. Gasoline compression ignition (GCI) is a new ignition method related to the extensive classification of combustion at low-temperature approaches. In this method of ignition, a fuel with high evaporation characteristics and low autoignition sensitivity, for instance gasoline, is burned in a high pressure process. Despite many research efforts, there are still many challenges related with GCI performance for compression ignition (CI) engines. Unstable combustion for idle- to low-load operation was observed because of the low reactivity characteristics of gasoline, and this will affect the efficiency and emissions of the engine. This paper contributes a detailed review of several topics associated with GCI engines and the effort to improve its efficiency and emissions, including its potential when using gasoline-biodiesel blends. Some recommendations are proposed to encourage GCI engines improvement and development in the near future

A Review of the External and Internal Residual Exhaust Gas in the Internal Combustion Engine

Efficiency and emission reduction are the primary targets of internal combustion engine research due the large number of vehicles in operation and the impact of emissions-related pollution on human and ecosystem health. Harmful components of engine exhaust gases include nitrous oxides (NOx), carbon dioxide, hydrocarbons, and particulate matter. NOx emissions in particular are associated with significant health threats. The recirculation of exhaust gases can reduce NOx emissions and improve engine efficiency when combined with other advanced techniques. On the other hand, the residual exhaust gas also effects on the quality of lubricating engine oil and therefore causes an increase in engine piston ring wear. In this review paper, the effects of external and internal exhaust gas recirculation on the performance and emission characteristics of diesel, gasoline, and alternative fuel engines are summarized and discussed in detail. Because it is difficult to estimate the internal residual exhaust gas in the combustion engine by doing experiments. This review paper introduces control strategies and prediction methods for internal and external exhaust gas recirculation

A study effects of injection pressure and wall temperature on the mixing process of NOx and NH3 in Selective Catalytic Reduction system

Diesel engines are commonly used for public transportation on-road and off-road applications. Growth production of the diesel engine is very significant from year to year. Nitride Oxide (NOx) from diesel engine was one of the major sources of air pollution. Selective Catalytic Reduction (SCR) has been successfully used to reduce NOx from a diesel engine with a chemical reaction from ammonia (NH3). The mixing reaction between NOx and NH3 reaction can produce steam (H2O) and Nitrogen (N2). However, ammonia uniformity pattern usually not homogenization and the ammonia was difficult to mix with NOx. The constant air flows incomplete to assist the spray injector to spread NH3 to all corners of SCR. The impact study of turbulent phenomena and standard k-epsilon Low-Reynolds Number model to the mixing process in the SCR system using STARCCM+. The simulation studies are conducted under different pressure (4 to 6 bars), the injection rate (0.04 g/s) and temperature (338 K – 553 K) and the high pressure and high velocity magnitude creating turbulent swirl flow. The ammonia decomposition process and mixing process with NOx were investigated using a box with optical access. The simulation and numerical study results validated using back pressure value and the distribution of NOx concentration value from the catalyst outlet. The wall temperature will increase the urea evaporation to generate ammonia and gas pressure will increase the mixing process and chemical process in the SCR system. These reactions enable to optimize the SCR system technology which eventually able to reduce the NOx quantity from a diesel engine