• Journal of the Korean Institute of Gas
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• v.20 no.4
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• pp.44-49
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• 2016

This paper presents characteristics of diesel combustion and emissions according to adoption of various combustion chamber geometry. In order to suggest suitable combustion chamber geometry of the common rail diesel engine for electric generative use, 5 type of geometry chamber was found performance for combustion chamber to respond fuel efficiency. Combustion chamber geometry affects combustion characteristics due to change target area of spray in the combustion chamber and the main factor was the bowl aspect ratio of combustion chamber. Using the results of simulation, the effects of the variable combustion chamber can be improved the fuel efficiency for electric generation.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.6
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• pp.745-752
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• 2003

Injection technology is one of the important technologies in a diesel engine. Many studies have done on the injection system. In this study, the fuel chamber geometry, the orifice ratio and the needle lift of the injection valve of a diesel engine for generating electricity are varied and tested. The injection pressure, duration and spray shapes are produced with pressure transducer, needle lift sensor and highspeed camera. The result shows that the nozzle hole size has influence on the rail pressure and injection duration sensuously.

• Advances in aircraft and spacecraft science
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• v.9 no.6
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• pp.537-551
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• 2022

The rapid decrease of fossil fuel resources and increase of environmental pollution caused by aviation industries have become a severe issue which leads to an increase in the greenhouse effect. The use of biofuel becomes an option to alleviate issues related to unrenewable resources. This study presents a computational simulation of the biofuel combustion characteristics of various alternative fuels in an annular combustion chamber designed for training aircraft. The biofuels used in this study are Sorghum Oil Methyl Ester (SOME), Spirulina Platensis Algae (SPA) and Camelina Hydrotreated Esters and Fatty Acids (CHEFA). Meanwhile, Jet-A is used as a baseline fuel. The fuel properties and combustion characteristics are being investigated and analysed. The results are presented in terms of temperature and pressure profiles in addition to the formation of NOx and soot generated from the combustion chamber. Results obtained show that CHEFA fuel is the most recommended biofuel among all four tested fuels as it is being found that it burns with 37.6% lower temperature, 15.2% lower pressure, 89.5% lower NOx emission and 8.1% lower soot emission compared with the baseline fuel in same combustion chamber geometry with same initial parameters.

• Journal of the korean Society of Automotive Engineers
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• v.12 no.6
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• pp.40-47
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• 1990

The combustion chamber geometry, especially cavity geometry have an effect on the air-fuel mixture process, gas flow in cylinder and combustion itself. There types of piston cavity model were compared in order to investigate with the effect of cavity geometry on combustion characteristics, engine performance and exhaust gas emission; as the results Reflex type has superior performance compared with the other cavity types.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.4
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• pp.31-38
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• 1992

The objective of this study is to determine the ignition feasibility of a single shot, air-assisted gasoline fuel injector operated in a constant volume combustion chamber under atmospheric condition. A number of parameters has been selected for this experiments, such as dwelling time, spark gap position(r,z), spark electrode geometry, supplied air and fuel masses and spray cone deflector angle. On-site visual inspection of the instantaneous flame glow was chosen as one way to judge the successful ignition. In addition, chamber pressure and occasional photography were mobilized as for data recording. It was clearly observed that there was an entrainment air-fuel mixture toward spray axis from the spray formation and its development later on. The optimum ignition conditions were found for those parameters given above.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.7
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• pp.1123-1130
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• 2004

Numerical simulations have been carried out to investigate the effect of nozzle hole geometry on the combustion characteristics of the large diesel engine. 6S90MC-C. Spray and combustion phenomena were examined numerically using FIRE code. Wane breakup and Zeldovich models were adopted to describe the atomization characteristics and NOx formation processes. Predictions on the cylinder peak pressure and NOx emission were first verified with the experimental data to confirm the reliability of numerical calculations. The comparison results showed good agreements within the range of 0.64% and 4.6% respectively. Finally, the effects of fuel spray angle and diameter on the engine performance were investigated numerically to find the optimum nozzle hole geometry considering fuel consumption, NOx emission and heat flux of the combustion chamber wall. It was concluded that the combustion gas recirculation in cylinder by changing fuel injection direction is an effective method to reduce NOx emission by about 10% with increasing fuel oil consumption, 1.4% in a large diesel engine.

• Journal of ILASS-Korea
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• v.17 no.4
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• pp.171-177
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• 2012

To understand oxygenated fuel characteristics including spray penetration length and spray angle at a real engine ambient pressure condition, DME was injected into a high pressure chamber by a piezo injector common rail system. The piezo injector common rail system was able to apply steady injection pressure, rapid response, and accurate injection quantity. Injection and ambient pressure were varied to confirm a relation with spray form. Using a direct photographing technique, development process of DME spray was captured. DME injection quantity was enlarged linearly as increasing of the injection pressure. In the high pressure chamber, when the injection pressure was enlarged the penetration length and velocity were increased due to a big momentum of fuel particle at the same ambient pressure. When ambient pressure was increased, the DME spray penetration length and velocity were decreased since the high ambient density of nitrogen was acted as a resistance. Although the ambient pressure and injection pressure were varied, each case of spray angle was almost same since the spray angle had a connection of the injector nozzle geometry.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.211-219
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• 1996

In a small high-speed D. I. diesel engine, the injected fuel spray into the atmosphere of the high temperature is burnt by go through the process of break up, atomization, evaporation and process of ignition. These process are important to decide the emission control and the rate of fuel consumption and out put of power. Especially, in the case of injected fuel spray impinging on the wall of piston cavity, the geometry of piston cavity gives great influence the ignitability of injected fuel and the flame structure. Ordinary, the combustion chamber of driving engine have unsteady turbulent flow be attendant on such as the change of temperature, velocity and pressure. So the analysis of spray behavior is difficult. In this study, the spray was impinged on the wall of 3 types of piston cavity such as Dish, Toroidal, Re-entrant type, in order to analyze the combustion process of impinging spray precisely and systematically. And hot wire probe was used for analyze non-steady flow characteristics of impinging spray, and to investigate the behavior of spray, the aspects of concentration c(t), standard deviation σ(t) and variation factor(vf) was measured with the lapse of time.

• Journal of ILASS-Korea
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• v.26 no.2
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• pp.57-66
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• 2021

The reactivity controlled compression ignition (RCCI) is the technology that provides two different types of fuel to the combustion chamber with the advantage of significantly reducing particulate matter and nitrogen oxides emissions. However, due to the characteristics of lean combustion, combustion efficiency is worsened. The conventional type of pistons for conventional diesel combustion (CDC) has mostly been used in the researches on RCCI. Because the pistons for CDC are optimized to enhance flow and target spray, the pistons are unsuitable for RCCI. In this study, a piston that is suitable for RCCI is designed to improve combustion efficiency. The new piston was designed by considering the factors such as squish geometry, bowl depth, and surface area. The experiment was carried out by fixing the energy supply to 0.9kJ/cycle and 1.5kJ/cycle respectively. The two pistons were quantitatively compared in terms of thermal efficiency and combustion efficiency.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.28-34
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• 2001

Great attentions are paid to HSDI diesel engine for passenger cars because of its high thermal efficiency. The most interesting research in HSDI diesel engine developments is focused on applying common rail system as a fuel injection equipment. In this study, a series of tests are carried out to investigate the effect of injection pressure variation on the smoke and fuel concluded in a small HSDI diesel engine with common rail system. As a result of this study it is concluded that there is an optimum rail pressure dependent on combustion system such as nozzle type, combustion chamber geometry.