• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.28 no.1
• /
• pp.45-52
• /
• 1992

In this paper, combustion characteristics and engine performance varying with blending rate of fish oil using five test fuels, e.g.pure diesel oil and four types of sardine-oil-blended diesel oils, their blending rates by weight being 20%, 40%, 60% and 80% respectively, and operating condition of engine, were investigated experimentally both in the constant volume combustion bomb and in the engine. The results are summarized as follows: 1) In the bomb, the influence of temperature on ignition delay of sardine-oil-blended diesel oils was larger than that of pure diesel oil, and it tended to increase as the blending rate of fish oil increase sardine-oil-blended diesel oils. As far as the influence of pressure on ignition delay concerns, there was no significant difference with all the test fuels. 2) In the engine, the ignition delay of fish-oil- blended diesel oils was longer than that of pure diesel oil, and it tended to increase as the blending rate increases. In the bomb, the ignition delay in high temperature showed no significant difference between with pure diesel oil and with fish-oil-blended diesel oils, and it was especially short with 60% fish-oil-blended diesel oil. In low temperature, however, the delay became longer as the blending rate increase. 3) The combustion duration was shorter with fish-oil-blended diesel oils than with pure diesel oil and it became a little shorter as the blending rate increases. 4) The rate of fuel consumption showed no significant difference between with fish-oil-blended diesel oils and with prue diesel oil, although calorific value of fish oil was lower than that of diesel oil. 5) Smoke density in exhaust gas was lower with fish-oil-blended diesel oils than with pure diesel oil and the higher the blending rate was, the lower the smoke density became.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.2
• /
• pp.166-174
• /
• 2014

Fuel injection pressure has steadily increased in diesel engines for the purpose of improving fuel efficiency and cleaning exhaust gas, but it has now reached a point, where the cost for higher pressure does not warrant additional gains. Common rail systems on modern diesel engines have fuel pumps that are mechanically driven by crankshaft. The pumps actually house two pumping module inside: a low pressure pump component and a high pressure pump component. Part of the fuel compressed by the low pressure component returns to the tank in the process of maintaining the pressure in the common rail. Since the returning fuel represents pumping loss, fuel economy improves if the returned fuel can be eliminated by using a properly controled electrical fuel pump. As the first step in developing an electrical fuel pump the fuel supply system on a 6 liter diesel engine was modeled with AMESim to analyze the workload and the fuel feed rate of the injection pump, and the results served as basis for selecting a suitable servo motor and a reducer to drive the pump. A motor controller was built using a DSP and a program which controls the common rail pressure using a proportional control method based on the target fuel pressure information from the engine ECU. A test rig to evaluate performance of the fuel pump is implemented and used to show that the newly developed electrically driven fuel pump can satisfy the fuel flow demand of the engine under various operating conditions when the rotational speed of the pump is adequately controlled.

• Journal of the Korean Institute of Gas
• /
• v.20 no.1
• /
• pp.52-61
• /
• 2016

Liquefied petroleum gas is regarded as a promising alternative fuel as it is eco-friendly, has good energy efficiency and output performance, practically and has high cost competitiveness over competing fuels. In spark-ignition engine, direct injection technology improves engine volumetric efficiency apparently and operates engine using the stratified charge that has relatively higher combustion efficiency. This study designed a combustion chamber equipped with visualization system by applying gasoline direct injection engine principle. In doing so, the study recorded and analyzed ignition probability and flame propagation process of spark-ignited direct injection LPG in a digital way. The result can contribute as a basic resource widespread for spark-ignited direct injection LPG engine design and optimization extensively.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.9 no.6
• /
• pp.7-15
• /
• 2010

Recently, with the high performance and efficiency of machine, there have been required the multi-functions in various machine parts, such as the heat resistance, the abrasion resistance and the stress resistance as well as the strength. Fatigue crack growth tests were carried out to investigate the fatigue characteristics of high carbon steel (SM53C) experienced by high-frequency induction treatment. The Cam nose part of the Automobile's Cam shaft is strongly bumped with rocker arm or valve-lift. Therefore abnormal wear such as unfair wear and early wear occur in the surface. This abnormal wear causes a defect that bad timing open and close actions of the engine valve happen in the combustion chamber so the fuel gas will be combustion imperfect. Therefore, the cam shaft demands high hardness and wear resistance. In this study, high frequency heat treatment has been accomplished while wear test for material SM53C.

• Proceedings of the KSME Conference
• /
• 2001.06e
• /
• pp.625-630
• /
• 2001

The inducers in liquid-rocket engines are to increase the inlet pressure of the pump to avoid any malfunction due to cavitation. Inducers are typically designed to be operated with some amount of cavitation for the compactness of the turbopump system. Also, inducers are designed to produce low headrise to prevent the decrease of the overall pump efficiency due to the low efficiency of inducers. In the present paper, a computational study on the hydrodynamic behavior of the inducer for the rocket-engine turbopump are presented including the effect of the mass flow rate under the constant rotational speed. As the mass flow rate is decreased, the inducer showed better performance with strong back flows which may have deleterious effects upon the anti-cavitation ability. But the adopted inducer showed very low headrise with high volume flow rates, which may be caused by the small passage area near the trailing edge. The modified version of the present inducer is proposed and numerically evaluated, which in turn showed better results.

• The KSFM Journal of Fluid Machinery
• /
• v.6 no.4 s.21
• /
• pp.50-57
• /
• 2003

The hydraulic performance analysis of a turbopump with an inducer for a liquid rocket engine was performed using three-dimensional Navier-Stokes equations. A simple mixing-plane method and a full interaction method were used to simulate inducer/impeller interaction. Two methods show almost similar results due to the weak interaction between the inducer and impeller since the inducer outlet blade angle is lather small. But, when the inducer and the impeller are closely spaced near the shroud region, flow angles at the impeller inlet show different results between two methods. Thus, the full interaction method predicts about $2\%$ higher pump performance than the mixing-plane method. And the effects of prewhirl at the impeller inlet are also investigated. As the inlet flow angle is increased, the head rise and the efficiency are decreased. The computational results are compared with measured ones. The computational results at the design point show good agreements with experimental data, however under-predicts the head rise at high mass flow rates compared to the experiment.

• Journal of Powder Materials
• /
• v.18 no.6
• /
• pp.517-525
• /
• 2011

In this study, the used DOCs, which could remove the air pollutants such as CO and HC in the exhaust gas from diesel vehicle, were remanufactured by various conditions. Their catalytic performances and characterization were also investigated. The remanufacturing process of the deactivated DOCs includes high temperature cleaning of incineration, ultrasonic cleaning for washing with acid/base solutions to remove deactivating materials deposited to the surface of the catalysts, and active component reimpregnation for reactivating catalytic activity of them. The catalytic performance tests of the remanufactured DOCs were carried out by the diesel engine dynamo systems and chassi dynamo systems in CVS-75 mode. All prepared catalysts were characterized by the optical microscopes, SEM, EDX, porosimeter and BET to investigate correlations between catalytic reactivity and surface characteristics of them. The remanufactured DOCs at various conditions showed the improved catalytic performances reaching to 90% of fresh DOC, which is attributed to remove the deactivating materials from the surface of the used DOC through the analysis of catalytic performance test and their characterization.

• Journal of ILASS-Korea
• /
• v.12 no.2
• /
• pp.86-93
• /
• 2007

There is a growing interest to develop an eco-friendly air cleaner with high performance through a remanufacturing process. Two kinds of polyurethane filter media, a coarse (Filter-A) and a fine filter media (Filer-B), are used in this study to protect a vehicle engine from airborne particles. In order to improve the collection performance of the filters (Filter-A, Filter-B), an oil coating technology on the filter surface was introduced. As a result, inertial force is a dominant collection mechanism for a dry filter media, so that collection efficiency increases with increasing filtration velocity. However, intra-structure change of an oil-coated filter media influences on the collection mechanism, which shows a non-linear collection efficiency curve in terms of filtration velocity. The result shows that the developed filter media are eco-friendly and effective to protect a vehicle engine from airborne particles especially at low filtration velocity.

• 한국전산유체공학회:학술대회논문집
• /
• 2004.10a
• /
• pp.95-99
• /
• 2004

The developing Smart UAV in KARI supposes high speed flight as like a conventional plane, as well as vertical takeoff and landing as like a helicopter. Therefore, the air intake system should be designed to provide the sufficient air flow to the engine and the maximum possible total pressure recovery at the engine intake screen over a wide range of flight conditions. For this purpose, we designed the intake system using a pilot type intake model and plenum chamber In this paper, we designed the intake model and analyzed the performance of designed intake system using the general-purpose commercial CFD code, CFD-ACE+ For 3-D calculation, we generated mesh using the unstructured gird and used $\kappa-\epsilon$ turbulence model. The analysis results of the total pressure variation and the velocity distribution was illustrated in this paper. The pressure recovery and distortion coefficient at a plane coincident with the compressor inlet were calculated and streamline variation through the intake system was investigated at the worst condition as well as the standard flight condition.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.12 no.3
• /
• pp.9-15
• /
• 2008

Nozzle flow analyses of $30\;ton_f$-class KARI liquid rocket engine for high altitude propulsion are carried out using a chemically frozen and equilibrium flow analysis code developed previously. It is considered that the combined frozen- and shifting- equilibrium analysis is cost-effective regarding the convergence characteristics and modeling uncertainties, though the non-equilibrium analysis is most reliable approach. A dependable performance prediction could be attainable through the present analyses that account for the recombination process and thermal and kinetic energy recovery during the expansion process with viscous effects.