• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.235-238
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• 1998

This paper presents the detection of internal combustion engine's multiple misfire. The primary cause of air pollution by vehicles is imperfect conbustion of fuel. The CARB(California Air Resources Board) have imposed regulations for the detection of misfiring in automotive engines. The OBD-II regulations requir that misfire should be monitored by the diagnostic system, and that the goal of OBD-II is to alert the driver to the presence of a malfunction of the emission control system. Present invention based upon measurements of engine roughness as derived from crankshaft angular velocity measurements with special signal processing method. Crankshaft angular velocity signals are processed by walsh-fourier transform. Experimental work confims that it's possible to apply walsh-fourier transform for the detection of multiple misfires in no-load idle and road testing.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.96-103
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• 2005

One of the major problems limiting the accuracy of piezoelectric transducers fur cylinder pressure measurements in an internal combustion (IC) engine is the thermal shock. Thermal shock is generated from the temperature variation during the cycle. This temperature variation results in contraction and expansion of the diaphragm and consequently changes the force acting on the quartz in the pressure transducer An empirical equation for compensation of the thermal shock error was derived from consideration of the diaphragm thermal deformation and actual pressure data. The result indicate that the thermal shock equation provides reliable correction based on known surface temperature swing.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.3
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• pp.243-248
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• 2013

Internal combustion engines typically expel 30%-40% of the energy supplied by fuel to the environment through their exhaust system. Therefore, further significant improvements in the thermal efficiency of IC engines are possible by recovering the waste heat from the engine exhaust gas. With this fact in mind, a numerical simulation was carried out to investigate the potential of using thermoelectric generation with an internal combustion engine for waste heat recovery. Physical parameters such as the exhaust temperature and mass flow rate were evaluated in the exhaust system, and the optimum location for inserting a thermoelectric generator (TEG) into the system was determined. The TEG will be located in the exhaust system and will use the energy flow between the warmer exhaust gas and the external environment. The optimum position of the temperature distribution and the TEG performance were predicted through numerical analysis. The experimental results obtained showed that the power output significantly increases with the temperature difference between the cold and hot sides of the TEG.

• Journal of ILASS-Korea
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• v.21 no.3
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• pp.144-154
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• 2016

This review will be concentrated on the spray characteristics of biobutanol and its blends fuels in internal combustion engines including compression ignition, spark ignition and gas turbine engines. Butanol can be produced by fermentation from sucrose-containing feedstocks, starchy materials and lignocellulosic biomass. Among four isomers of butanol, n-butanol and iso-butanol has been used in CI and SI engines. This is due to higher octane rating and lower water solubility of both butanol compared with other isomers. The researches on the spray characteristics of neat butanol can be classified into the application to CI and SI engines, particularly GDI engine. Two empirical correlations for the prediction of spray angle for butanol as a function of Reynolds number was newly suggested. However, the applicability for the suggested empirical correlation is not yet proved. The butanol blended fuels used for the investigation of spray characteristics includes butanol-biodiesel blend, butanol-gasoline blend, butano-jet A blend and butanol-other fuel blends. Three blends such as butanol/ethanol, butanol/heptane and butanol/heavy fuel oil blends are included in butanol-other fuel blends. Even though combustion and emission characteristics of butanol/diesel fuel blend in CI engines were broadly investigated, study on spray characteristics of butanol/diesel fuel blend could not be found in the literature. In addition, the more study on the spray characteristics of butanol /gasoline blend is required.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.183-186
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• 2011

In this paper, we present some results of power analyses, and weight estimation on electric propulsion systems for Personal Air Vehicles(PAV) applications. When hybrid electric propulsion is adopted, its power performance using fuel cells and batteries is inferior to that of internal combustion engines for 1,000 kg PAV. However, hybrid electric propulsion systems may replace IC engines when energy density and power density is over $0.75kW{\cdot}hr/kg$and 2.5 kW/kg, respectively.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.67-74
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• 1998

The primary cause of air pollution by vehicles is imperfect combustion of fuel. One of the most usual causes of this imperfect combustion is the misfire in IC engins. The U.S. EPA(Environment Protection Agency) and the CARB(California air Resources Board) have imposed regulations for the detection of misfiring in automotive engines. The OBD-II regulations require that misfire should be monitored by the engine diagnostic system, and that the goal of OBD-II is to alert the driver to the presence of a malfunction of the emission control system. Several solutions to the misfire detection problem have been proposed for the detection of misfires. However, the performance of these methods in the presence of misfire is not altogether clear. This paper presents a precise method and system for internal combustion engine misfire. Present invention based upon measurements of engine roughness as derived from crankshaft angular velocity measurements with special signal processing method. Crankshaft angular velocity signals are processed by WDPT, so that the more reliable misfire detection than the time domain analysis. Experimental work confirms that it is possible to apply the WDFT for the detection of misfires in no-load idle and road testing.

• International journal of advanced smart convergence
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• v.4 no.1
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• pp.54-63
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• 2015

Increasing air pollution levels and the global oil crisis has become a major hindrance in the growth of our automobile sector. Traditional Internal Combustion engines running on non-renewable fuels are proving to be the major culprit for the harmful effects on environment. With few modifications and also with assistance of few additional components current small SI engines can be modified into a pneumatic engine (commonly known as Compressed Air Engines) without much technical complications where the working fluid is compressed air. The working principle is very basic as adiabatic expansion of the compressed air takes place inside the cylinder pushing the piston downwards creating enough MEP to run the crank shaft at decent RPM. With the assistance of new research and development on pneumatic engines can explore the potential of pneumatic engines as a viable option over IC engines. The paper deals with analysis on RPM variation with corresponding compressed air injection at different crank angles from TDC keeping constant injection time period. Similarly RPM variation can also be observed at different injection pressures with similar injection angle variation. A setup employing a combination of magnetic switch (reed switch), magnets and solenoid valve is used in order to injection timing control. A conclusive data is obtained after detailed analysis of RPM variation that can be employed in newly modified pneumatic engines in order to enhance the running performance. With a number of benefits offered by pneumatic engine over IC engines such as no emissions, better efficiency, low running cost, light weight accompanied by optimized injection conditions can cause a significant development in pneumatic engines without any major alteration.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.6
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• pp.1-8
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• 2010

In this paper, we present some results of technical surveys, power analyses, and weight estimation on electric propulsion systems for 1-ton class Personal Air Vehicles(PAV) applications. When hybrid electric propulsion is adopted, its power performance using fuel cells and batteries in inferior to that of internal combustion engines. However, hybrid electric propulsion systems may replace IC engines when energy density and power density reach 0.75 kW$^*$hr/kg and 2.5 kW/kg, respectively.

• Advances in Automotive Engineering
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• v.1 no.1
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• pp.79-104
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• 2018

A detailed literature review is presented for the applications of the heat pump technologies on the electric vehicles Heating, Ventilation and Air Conditioning (HVAC) system. Due to legal regulations, automotive manufacturers have to produce more efficient and low carbon emission vehicles. Electric vehicles can be provided these requirements but the battery technologies and energy managements systems are still developing considering battery life and vehicle range. On the other hand, energy consumption for HVAC units has an important role on the energy management of these vehicles. Moreover, the energy requirement of HVAC processes for different environmental conditions are significantly affect the total energy consumption of these vehicles. For the heating process, the coolant of internal combustion (IC) engine can be utilized but in electric vehicles, we have not got any adequate waste heat source for this process. The heat pump technology is one of the alternative choices for the industry due to having high coefficient of performance (COP), but these systems have some disadvantages which can be improved with the other technologies. In this study, a literature review is performed considering alternative refrigerants, performance characteristics of different heat pump systems for electric vehicles and thermal management systems of electric vehicles.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.1
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• pp.72-79
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• 2009

Recently, the internal combustion engines have focused on reducing the $CO_2$ gas in order to cope with severe regulations for fuel economy. Therefore, various new technologies have been developed. Among them, cooling system is spotlighted because it has great effect on fuel economy. In this study, we measured the friction losses of engine parts according to engine speed and oil temperature. We also obtained optimized oil temperature which has the minimum friction losses. Then, we selected optimized oil temperature range and gave informations of friction losses for each engine parts. In addition, we analyzed relationship between coolant temperature and oil temperature by using engine performance test system. From this experiment, we obtained the database for relationship between coolant temperature and oil temperature. Then, we found the optimal temperature about engine oil. We analyzed BSFC and exhaust emissions by controlling the high coolant temperture. If we controlled coolant temperature more higher, BSFC has a little difference but exhaust emissions such as THC and CO have reduced. By using these experimental results, we predicted that IC engine have more low fuel consumption and exhaust emissions by optimized cooling control strategy.