• International Journal of Automotive Technology
• /
• v.8 no.4
• /
• pp.403-411
• /
• 2007

This article describes a methodology based on experiments and 1D modeling work related to the exhaust system analysis of a small two-stroke engine. The primary goal of this work was to understand how the design criteria of a compact exhaust system influenced the exhaust port pressure, since its evolution controls not only engine performance but also exhaust emissions. On the experimental side, a fully instrumented 50cc two-stroke engine was used to check the behavior of three different exhaust systems. A problem related to instantaneous pressure measurements in unsteady, hot flow was detected and solved during the study. To build the 1D model of the three exhaust systems, experimental information on the steady flow and the impulse test rigs was obtained under controlled conditions in specific facilities. Accurate comparisons between measured and calculated exhaust port instantaneous pressures were obtained from the following different exhaust system configurations: a straight duct, a tapered pipe and the three compact exhaust systems. The last step in the method used this model to analyze the pressure waves inside the exhaust system and detect the influence of the geometric parameters. The results should lead to improvements in the design process of complex compact exhaust systems in two-stroke engines.

• Journal of ILASS-Korea
• /
• v.20 no.3
• /
• pp.141-148
• /
• 2015

In order to research engine characteristics of spark-ignited engine with intake valve closing timing change for Miller cycle, two cam for LIVC(Late Intake Valve Closing) were designed and fabricated an prototype valvetrain. And intake valve closing timing were adjusted to build low compressing and high expansion cycle for HEV. In experimental study, it were investigated with different engine speed, spark timing and air-fuel ratio to compare base cam and LIVC cam type. It was found that the volumetry efficiency and effective work of compression process were decreased in case of LIVC cam. When compared with the existing results, the maximum pressure in the cylinder was reduced about 12~13 bar and the volumetric efficiency was reduced about 16%.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.35 no.9
• /
• pp.805-815
• /
• 2007

In order to build a conceptual design program for a liquid rocket engine system, performance based sub-programs for each core component of the engine system were made. Parts included were the combustion chamber, supersonic nozzle, centrifugal pump, and impulsive turbine. Simple mathematical models based on classical thermodynamic and inviscid theories were adopted with proper tuning by empirical data. In Part I, aiming to validate each sub-program, we examined the results of each program qualitatively, and parametrically investigated the sensitivity due to the change in design parameters.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.7 no.8
• /
• pp.107-115
• /
• 1999

Hydrocarbon emission from spark ignition engines deeply relates with fuel evaporation mechanism. Therefore, fuel evaporation on the back of the intake valve is very important to understand fuel evaporation mechanism during engine warm up period. Intake valve heat transfer model was build up to estimate the amount of fuel evaporation on the intake valve back . Intake valve temperature was measured intake valve temperature is increased rapidly during few seconds right after engine start up and it takes an important role on fuel evaporation. The liquid fuel evaporation rate on the intake valve back proportionally increases as valve temperature increases, however its contribution slightly decreases as intake port wall temperature increases. The fuel evaporation rate on the valve back is about 40∼60% during engine warm-up period and it becomes about 20∼30% as intake port wall temperature increases. The estimation model also makes possible model also makes possible to review the effect of valve design parameters such as the valve mass and seat area on fuel evaporation rate through intake valve heat transfer.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.25 no.2
• /
• pp.119-143
• /
• 2021

Selecting liquid methane as fuel is a prevailing trend for recent rocket engine developments around the world, triggered by its affordability, reusability, storability for deep space exploration, and prospect for in-situ resource utilization. Given years of time required for acquiring a new rocket engine, a national-level R&D program to develop a methane engine is highly desirable at the earliest opportunity in order to catch up with this worldwide trend towards reusing launch vehicles for competitiveness and mission flexibility. In light of the monumental cost associated with development, fabrication, and testing of a booster stage engine, it is strategically a prudent choice to start with a low-thrust engine and build up space application cases.

• The Journal of the Korea Contents Association
• /
• v.5 no.3
• /
• pp.133-140
• /
• 2005

It is important matter to develop game that language should consider improving game development environment. It is hardly any language that is designed to develop a game. Most developer used general purpose programming language in these situations, and directly modeling with engine. For this reasons, developers cannot easily develop games and must programming on engine level. It is hard to develop a game in this environment that was not able to understand an engine well. Moreover, developer and planner want to use an abstracted high-level language on planner phase and are going to easily develop a game. It was not have communication tool between developer and planner. Therefore, we defined a script language for modeling based on abstract engine level. In addition, we did build IDE to develop game using abstracted high-level language. It was able to develop a game on high-speed development environment. Therefore, developer does not must develop with engine phase but can develop a game with planners. In addition, game planner and developer can use a communication tool because it is able to develop skeleton game.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2010.04a
• /
• pp.852-855
• /
• 2010

Tree type of Rule Case will be processed by the method that provide practical Rule Case to Rule Engine that is made with procedural language beforehand, then the Rule Engine according to the condition of the special Rule Case to return result in current Rule-Based System. There are two disadvantages in the method; the first is according to specific business rule after construct the Rule Engine when the business rule changing the Rule Engine also must be changed. The second is when Rule have many conditions the Rule Engine will become very complex and the speed of processing Rule Case will become very slow. In this paper, we will propose a simplified algorithm that according to the theory of ID Tree to produce Rules which be used in Rule-Based System. The algorithm can not only produce Rules but also make sure of satisfying change of business rule by execute the algorithm. Because it is not necessary to make a Rule Engine, we will anticipate effect of increasing speed and reducing cost from Rule-Based System of applying the algorithm.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.6
• /
• pp.800-806
• /
• 1999

This paper proposes IIKBAG(Intelligent Interlocking Knowledge Base Generator) which can build automatically the interlocking knowledge base utilized as the real-time interlocking strategy of the electronic interlocking system in order to enhance it's reliability and expansion. The IIKBAG consists of the inference engine and the knowledge base. The former has an auto-learning function which searches all the train routes for the given station model based on heuristic search technique while dynamically searching the model, and then generates automatically the interlocking patterns obtained from the interlocking relations of signal facilities on the routes. The latter is designed as the structure which the real-time expert system embedded on IS(Interlocking System) can use directly in order to enhances the reliability and accuracy. The IIKBAG is implemented in C computer language for the purpose of the build and interface of the station structure database. And, a typical station model is simulated to prove the validity of the proposed IIKBAG.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2011.11a
• /
• pp.52-55
• /
• 2011

Embedded system developers use design and testing tools to make their product faster. Previously developed a virtual development environment for embedded software (VDEES) using open source software, mainly the SID simulation framework for a simulator engine and the Eclipse platform for a development platform. VDEES enables developers to develop SID Component in C++. A bridge module for developing SID Component in Java has been developed and available. However, using this module, developers have to build their SID Java component from scratch. In this work, we developed SID Java Component Builder Plug-in as an additional features to VDEES. This tools enables developers to build SID Component in Java faster and easier.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.11a
• /
• pp.684-687
• /
• 2005

KIER has been running a demonstration project for 10kWe solar thermal power generation. the project is to build and operate the first solar thermal power generation system in Korea. For concentrating solar thermal energy $40m^2$ dish type concentrator was adapted and a stirling engine is going to be integrated to the system for power production. At the moment building the dish concentrator including mirror and sun tracking system was completed and it's performance are being closely evaluated. This paper will introduce some detailed designs and construction procedures which we have experienced so far.