• Journal of the korean Society of Automotive Engineers
• /
• v.15 no.1
• /
• pp.37-44
• /
• 1993

Fuel injection system is an important tool in the exhaust emission and performance of a diesel engine. Effects of the fuel injection system in diesel combustion was investigated experimentally by measuring the performance and analyzing the combustion phenomena in a D.I. diesel engine. The selected injection parameters were nozzle opening pressure, nozzle projection length, and nozzle spray angle. From the measured results, it is shown that the fuel injection pipe diameter is an effective means to improve engine performance in a middle and high speed range and the 2 stage spring nozzle holder has the advantage of increasing the engine performance due to the initial injection pressure in a low speed range. It has been also shown that increasing nozzle opening pressure resulted in decrease in smoke, but increase in NO$_{x}$ from the engine.e.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2007.11a
• /
• pp.83-88
• /
• 2007

The spray characteristics and liquid column penetration of steady and pulsed injection measurements have been experimentally studied using high speed camera in liquid jets injected into subsonic crossflow. The objectives of this research are to comparison the spray characteristics of steady injection with pulsed injection. Moreover. the effects of frequency are also studied. As the result, This research has been showed that pulsed injection has different penetration compared with steady injection.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.24 no.5
• /
• pp.377-384
• /
• 2012

Vapor injection technique has been applied to prevent performance degrdation of a heat pump at low ambient temperatures. In this study, the heating performance of a heat pump with a variable speed injection scroll compressor using R-410A was investigated by applying sub-cooler vapor injection(SCVI) and flash tank vapor injection(FTVI). The heating performance of the heat pump was measured by varying compressor frequency and outdoor temperature. The heating capacity of the FTVI system was 8~10% higher than that of the SCVI system at all operating conditions. On the other hand, the heating performance improvement with the increase in the compressor frequency was more prominent in the SCVI system than in the FTVI system.

• Journal of Energy Engineering
• /
• v.14 no.3 s.43
• /
• pp.173-179
• /
• 2005

Fuel injection system has more benefits in power, fuel consumption and emission than carburetor system even in high speed small engine. Up to date fuel injection system is used in motor car but is not used in motorcycles in Korea. EFI (Electronic fuel injection) system which has ECU can control precise fuel supply to variable RPM in engine. The purpose of this study is the investigation of effects of fuel injection system to improve the engine performance and efficiency in variable revolution of high speed small engine which is 4 Valves SOHC single cylinder engine used in motorcycle.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.3
• /
• pp.43-49
• /
• 2013

This work investigated the effects of engine speed and injection timing on combustion and emissions characteristics in a partially premixed charge compression ignition (pPCCI) engine fueled with DME. pPCCI engine especially has potential to achieve more homogeneous mixture in the cylinder, which results in lower NOx and smoke emission. In this study single cylinder engine was equipped with common rail and injection pressure is 700 bar. Total injected fuel mass is 64.5 $mm^3$ per cycle. The amount of pilot injection of the entire injection 12.5% is tested. Results show that NOx emission is decreased while IMEP is increased as the retard of injection timing. Besides, NOx emissions are slightly rised as well as IMEP is increased with the increase of engine speed.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.3 no.3
• /
• pp.46-51
• /
• 2004

Nowadays, plastic industry has needed to produce parts that require high precision and quality. To make a high precision and quality part, before injection molding, plastic material in investigated about their properties such as shrinkage, warpage, etc. In this study, experiments were conducted with PP(polypiopylene) to figure out shrinkage behavior according to three type aspect ratio of samples. The injection speed that affects on shear late, molecular orientation within plastic part was determined as main variable of experiment. As a result of experimental study, part shrinkage had a tendency to be decreased by increasing injection speed and aspect ratio of samples.

• Design & Manufacturing
• /
• v.11 no.1
• /
• pp.14-18
• /
• 2017

Recently, the injection-molded products are lighter, and thinner than ever. In this work, Injection molding simulation was conducted to analysis the filling pattern imbalance in high speed injection molding process for thin-wall injection component, 8 inches LGP. Numerical analysis shows that shear heated polymer near the side wall causes filling imbalance between center and side of cavity. Short shot experiments were conducted and compared with simulation results. Filling imbalance ratio showed a tendency to increase for wider fan gate.

• Journal of the korean Society of Automotive Engineers
• /
• v.12 no.5
• /
• pp.76-84
• /
• 1990

To study diesel fuel spray behavior, an experimental study was undertaken to investigate injection characteristics in vary ing back pressure and atomization mechanism in a non-evaporating diesel spray. Generally, injection characteristics is the curve of fuel flow plotted against time. The area under this curve is equal to the total quantity of fuel discharged for one injection. The method that measures rate of injection is long tube-type fuel rate indicator. Diesel spray injected into a quiescent gaseous environment under high pressure is observed by taking high speed camera by the focused shadow photographs. The results show that, at the start of injection, as the injected fuel rushes into the quiescent atmosphere the spray angle becomes large. Finally the spray stabilizes at a constant cone angle. Spray penetration length increases with the injection pressure.

• Design & Manufacturing
• /
• v.9 no.3
• /
• pp.24-28
• /
• 2015

Speaking in general terms the form injection process can be described as a new process-variant of already known structural foam molding technology which roots go back to the early sixties. The most limiting factors of already know foaming processes are large cell size and the lack of uniformity of these cells as well and the inability to foam all kinds of plastic materials. In this paper, Process Study on weight change in injection rate during foaming. Experimental conditions were set as the injection speed 50,150,300 and 450 mm/s. The experiments PA, PA+GF, PP, was confirmed that the weight increase to PP+TA.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.10a
• /
• pp.259-264
• /
• 2005

The shrinkage of the product in injection molded part occurs due to the volume change with variation of temperature and pressure and is influenced by the processing conditions of injection molding. Mold designers greatly concerns the shrinkage of parts for a high dimensional accuracy. In this study, bar type HIPS specimen with 15x19 grid on the surface was tested. The amount of shrinkage of flow and transverse directions was examined with respect to the injection molding conditions such as melt temperature, injection speed, holding pressure, mold temperature and cooling time. As the packing pressure increased, the difference of shrinkage of both directions is decreased and the absolute shrinkage value also decreased.