• Journal of Power System Engineering
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• v.10 no.3
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• pp.5-10
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• 2006

In a conventional and lean operating engine, the state of mixture is very important in the combustion and emission characteristics. Lean operation is known to decrease the formation while maintaining a good fuel economy, but the unstable operation due to misfire and erratic combustion prevents engines from being operated at very lean mixtures, so both combustion rates and exhaust emission formation need to be satisfied comparably. In this study, it is designed and experimented the modified engine, and analyzed the combustion and exhaust emission according to the change of engine speed and with adding ozone. The conclusions were drawn out and enumerated as follows. 1. At the experimental result of automobile diesel engine, it has been verified that the formation of particulate matter(PM) gas is able to be lower with the addition of optimum quantities of ozone. 2. Carbon monoxide(CO) was formed by the lack of oxygen and the thermal dissociation in the combustion process. Therefore, with the change of swirl valve's position and addition of oxygen and ozone, CO formation was decreased by the increasing of excessive O2, but it was increased by the temperature of combustion gas growing higher. As a result of the two effects, CO formation was decreased in this study. 3. Hydrocarbon(HC) was formed by the lack of O2, and the flow of mixture in cylinder. According to opening of the swirl valve and adding the oxygen and ozone, hydrocarbon gas was decreased by 20%, 9%, and 27.5%, respectively. 4. Nitric oxides($NO_x$) was strongly affected by the combustion gas temperature. As a result of respectively experimental conditions, $NO_x$ formation was increased about 20% due to (be the) high(er) combustion gas temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.498-503
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• 2012

It happens that the fuel is not injected when the driver doesn't push the acceleration pedal of vehicle with engine speed higher than 1,500rpm above the mid range of vehicle speed. This is called "fuel-cut function" and almost every modern vehicle is equipped with this function. This is activated frequently on the downhill area of highway and the quantity of vehicle-exhausted $CO_2$ gas can be zero on this area. With this fuel-cut function on the test highway, $CO_2$ gas from passenger car(2,000cc engine volume) can be reduced up to 4%. The fuel-cut function with CRUISE made in company AVL is simulated to find the most effective driving pattern on the downhill area. By simulating with CRUISE software, it is found that the lower limit of vehicle speed for fuel-cut should be raised to improve the fuel economy on the steeper downhill road. The fuel economy can be most economical when fuel-cut driving and reacceleration are completed on the section of downhill road.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.8-14
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• 2007

Compression ignition of homogeneous charges in IC engines indicates possibilities of achieving the high efficiency of DI diesel engines with low level of NOx and particulate emissions. The objectives of this study are to further understand the characteristics of the HCCI(Homogeneous charge compression ignition) combustion and to find ways of extending the rich HCCI operation limit in an engine-like environment. DME fuel is supplied either in the form of premixture with air or directly injected in the combustion chamber of a rapid compression and expansion machine under the conditions of various equivalence ratio and injection timing. The cylinder pressure is measured and the rate of heat release is computed from the measured pressure for the analysis of the combustion characteristics. The experimental data show that the RCEM can operate without knock on mixtures of higher equivalence ratio, when DME is directly injected in the combustion chamber than introduced as a fraction of a perfect or nearly perfect premixture. Very early fuel injection timings usually employed in HCCI operation are seen to have only insignificant effects in control of ignition timing.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.309-313
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• 2006

Many researchers have studied on the lightness of automobile. These researches are such as a body shell, sub frame, fuel tank, engine etc. The transmission Part is a magnitude one in the aspect of weight. A drive shaft (propeller shaft) transmits the engine power to rear differential gear assembly. It is used in the compact car that is a single drive shaft. But in the case of long body cars such as SUV (Sports Utility Vehicle), truck and large vehicle, two or three divided drive shaft are used to prevent the vibration damage from a drive shaft that has been taken high torsion and rotation. This multi-divided drive shaft structure is so heavy because it is assembled by yoke, center bearing and solid spline axis. When the rear axle move up and down, the spline shaft adjust the variation of a length between the transmission and rear axle gearbox. In this paper, it is studied in the experimental method that is a bending vibration characteristic of slip in tube shaped propeller shaft. This type propeller shaft is developed to combine the spline axis with drive shaft and can be light in weight of transmission part.

• Fire Science and Engineering
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• v.30 no.3
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• pp.1-6
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• 2016

More than five thousands transportation fires occurannually in Korea and the resulting destruction of property and loss of life is huge and results in traffic and environmental pollution. The recent development of automobile technology such as the hybrid concept and use of bio fuels makes fire protection even more difficult due to a lack of understanding of the new adapted system including vehicle engines. In this study, a numerical simulation was performed on a PSR (perfectly Stirred Reactor) to simulate an automobile engine and to clarify the effect of gasoline/ethanol surrogates as a fuel. The temperature, NOx and soot emissions were predicted to decrease with increasing ethanol content, but that of unburned hydrocarbons was found to increase dramatically. The result will provide not only the basic thermal characteristics for engines and their after-treatment systems, but also make it possible to assess the potential for fire events in these systems when an ethanol mixed fuel is used in gasoline vehicles.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1575-1580
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• 2011

A key factor in the study of hybrid vehicle is to enhance the usability of energy. The paper introduces the monitor and controlling technology of hybrid vehicle that can process the relevant information considering the structure of power system and driving strategies simultaneously, and can monitor its results. This technology, so called HEV algorithm analysis, has been applied to PRIUS THS made by Toyota Co. LTD. This model is adapted to parallel hybrid type. It has a somewhat comlex structure, but has several merits. It's energy loss is lower when conversing. and also it is easily applied to the conventional vehicle having a gasoline engine without any overall changing of its structure, and so on. This monitor and controlling technology is very useful to study on the various driving strategies of hybrid vehicle for maximizing the usability between engine and electric motor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.6
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• pp.495-504
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• 2021

Energy Harvesting is a technology that can convert wasted energy such as vibration, heat, light, electromagnetic energy, etc. into usable electrical energy. Among them, vibration-based piezoelectric energy harvesting (PEH) has high energy conversion efficiency with a small volume; thus, it is expected to be used in various autonomous powering devices, such as implantable medical devices, wearable devices, and energy harvesting from road or automobiles. In this study, wasted vibration energy in an automobile is converted into electrical energy by high-power piezoelectric materials, and the generated electrical energy is found to be an auxiliary power source for the operation of wireless sensor nodes, LEDs, etc. inside an automobile. In order to properly install the PEH in an automobile, vibration characteristics includes frequency and amplitude at several positions in the automobile is monitored initially and the cantilever structured PEH was designed accordingly. The harvesting properties of fabricated PEH is characterized and installed into the engine part of the automobile, where the vibration amplitude is stable and strong. The feasibility of PEH is confirmed by operating electric components (LEDs) that can be used in practice.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.2
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• pp.205-214
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• 2004

This paper presents design concepts, specifications and performances of a newly developed Black Box, the reconstruction analysis tool with the records, and results of validation tests. The Black Box can detect crash accidents automatically, and record the vehicle's motion and driver's maneuvers during a pre-defined time period before and after the accident. The items of the Black Box included the acceleration, yaw-rate, vehicle speed, engine RPM, braking application, steering and several digital inputs for recording driver's maneuvers. To detect the accident-related-crash, it is important to understand characteristics of the crash signal, which are much different from those of normal driving. Therefore, analytical considerations should be taken in designing pre-filtering circuits and selecting appropriate parameters for identifying crash accidents. And, it is necessary to select proper combination of motion sensors and design proper pre-filtering circuits in order to describe the vehicle's motion. The analysis algorithms were developed and implemented which can perform accurate detection of crash accidents, simulating pre-crash trajectories, and calculating parameters for reconstruction analysis of crash accidents. The developed Black Box was installed on passenger cars and several types of validation tests were conducted. Through the tests, the accuracy of the recorded data and usefulness of the analysis tool for reconstruction have been validated.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.3
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• pp.123-130
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• 2005

In this study, we evaluated the CH4 and CO conversion efficiencies over the oxidation catalysts for natural gas vehicle with lean-burn system. On the fresh catalyst, the conversion efficiency was increased when the loading of precious metal was increased. On the aged catalyst, the conversion efficiency was decreased as increasing the excess air ratio. We could confirm the measuring conversion efficiency of the unsteady state with the FTIR and that of steady state with the GC The temperature increasing ratio of unsteady state is acceptable from 3$^{\circ}C$/min. to 15$^{\circ}C$/min. for the evaluation of catalyst conversion performance , which has within the 4$\%$ of the difference of conversion efficiency. We observed a physical behavior of the thermal aged catalyst's surface using TEM and BET device. It was found that the precious metal was grown to the micro-scopic size by thermal aging process.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.7
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• pp.51-57
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• 2009

In this paper, we studied on an attenuation effect of automobile exhaust noise according to the direction of canceling speaker in duct-acoustic ANC system. Automobile exhaust noise was recorded at 800rpm, 3500rpm and 5000rpm of a diesel engine. Directions of canceling speaker can be set to $30^{\circ}$, $90^{\circ}$ and $150^{\circ}$ against the primary noise flow by acrylic ducts to be made for the experimentation. DSP board used to control the ANC system. The algorithm of this ANC system applied the Filtered-x-LMS algorithm that is modified to compensate for a property of DSP input signal and the secondary-path effect. As an experiment result, the direction of canceling speaker was proved to influence the reduction effect of noise. The $150^{\circ}$ duct in the attenuation effect of noise showed a better result than the $90^{\circ}$ or $30^{\circ}$ duct.