• Transactions of the Korean Society of Automotive Engineers
• /
• 제20권5호
• /
• pp.130-137
• /
• 2012

Automotive engines need strategies to satisfy with the emission regulations in terms of PM and NOx. HC-LNT (Hydrocarbon-Lean NOx Trap) with secondary injection system is considered as more practical technology in order to cope with emission regulations. The HC-LNT system, which is using diesel fuel itself as a reducing agent, absorbs NOx in lean exhaust gas condition and releases NOx in rich exhaust gas conditions. In this system, inappropriate amounts of reducing agent will slip through the LNT without the profits of conversion and cause additional emission problems. Therefore, the suitable amount of reducing agent should be supplied into the catalytic converter. In this research, engine emission test was conducted to optimize injection quantity at the various engine test conditions. Different exhaust layouts and catalyst shapes have been studied and extension unit which makes better uniformity of exhaust gas was used for HC-LNT system. From this results, the effect of secondary injection conditions on NOx conversion characteristics of HC-LNT was clarified.

• Transactions of the Korean Society of Automotive Engineers
• /
• 제20권5호
• /
• pp.95-101
• /
• 2012

An electric water pump for engine cooling system has an advantage which particularly in the cold start, the use of the electric water pump saves fuel and leads to a corresponding reduction in emissions. The canned type electric water pump without mechanical sealing elements was selected to meet the requirements for operational reliability and life. However, the electric water pump for internal combustion engine generates much more heat loss than for hybrid electric vehicle since it is operated by the electric power of high current and low voltage. In this study, the fluid flow and thermal characteristics of the canned type electric water pump as an inverter integrated water pump has been investigated under the effects of heat generation. The analysis conditions such as outdoor air temperature of $125^{\circ}C$, water pump speed of 6000 rpm, coolant temperature of $106^{\circ}C$ and coolant flow rate of 120 L/min was used as a standard condition. Therefore, flow fields and temperature distribution inside the water pump were obtained. Also, we checked the feasibility of the canned type for the electric water pump in comparison with the mechanical seal type.

• New & Renewable Energy
• /
• 제9권4호
• /
• pp.32-39
• /
• 2013

A 2-loop waste heat recovery system with Rankine steam cycles for the improvement of fuel efficiency of gasoline vehicles has been investigated. A high temperature loop is used to recover waste heat from exhaust gas and a low temperature loop is used to recover waste heat from cold engine coolant. This paper has dealt with a layout of low temperature loop system, the review of the velocity contours through numerical analysis. According to the result of analysis, the designed heat exchanger. And comparing with flow analysis results, LT Boiler is safe to operation.

• Transactions of the Korean Society of Automotive Engineers
• /
• 제24권6호
• /
• pp.694-701
• /
• 2016

According to revolutionary developments in automobile technologies, eco-friendly advanced vehicles (hybrid vehicle, hydrogen fuel-cell vehicle, electric vehicle, etc.) are rapidly increasing. The electromagnetic compatibility is getting more important for development of a vehicle because those advanced vehicles are driven by electric energy and equipped with more electric systems. In general, electromagnetic compatibility tests consist of an electromagnetic interference(EMI) test and an electromagnetic susceptibility(EMS) test. EMI test of the electric vehicles are needed not only in driving mode but also in charging mode because they must be recharged by much electric energy for driving. Depending on vehicle manufacturers, the charging device type and the location of charging device inlet in electric vehicles are various. In this paper, in order to investigate EMI of electric vehicles in charging mode in consideration of the direction of measuring antenna and the location of charging device inlet, a series of electromagnetic emission tests are conducted using three electric vehicles (neighborhood electric vehicle, electric vehicle and electric vehicle-bus). The test results show that electromagnetic emission measurements in charging mode are dependent on the direction of measuring antenna and the location of charging device inlet.

• Transactions of the Korean Society of Automotive Engineers
• /
• 제19권3호
• /
• pp.90-98
• /
• 2011

Noises from diesel engine are the major issues for noise pollution as well as affect customers' purchasing needs to vehicles powered by diesel engine. This study investigates to screen-out main factors that contribute to noises from diesel engine using VGT 2000cc engine developed recently. Changes of fuel temperature, intake temperature and the presence of three way catalyst don't affect the 'Engine Radiation Noise' and the solely three way catalyst influence on the 'Tail Pipe Noise'. Especially, there are no effects of the presence of three way catalyst on torque, which is main subject that should be considered in secondary study.

• Transactions of the Korean Society of Automotive Engineers
• /
• 제19권3호
• /
• pp.99-105
• /
• 2011

This paper described the effect of the multiple injections on the emission characteristics and combustion stability in a common rail diesel engine. In order to investigate the influence of multiple injections in a passenger car diesel engine, the injection strategy was varied with pilot injection, post injection and one main injection at various conditions. Based on the experimental results, the combustion and emissions characteristics were analyzed for the various injection strategies such as main, pilot-main, double-pilot-main, double- pilot-main-post injection strategy. It is revealed that the $NO_X$, HC and CO emissions are reduced by double pilot and post injection at medium load, however, soot emission is increased. Also, in the case of multiple injection, the combustion pressure is increased smoothly near the TDC and the coefficient of variation and fuel consumptions are decreased.

• Transactions of the Korean Society of Automotive Engineers
• /
• 제18권4호
• /
• pp.84-91
• /
• 2010

Owing to revolutionary developments in automobile technologies, a variety of advanced vehicles - hybrid vehicle, hydrogen fuel-cell vehicle, electric vehicle, etc. - emerges recently. The safety is getting more important for developing automobiles. The electro-magnetic compatibility has to be assured, since those advanced vehicles are equipped with various new electronic systems. Electro-magnetic compatibility tests, in general, consist of an EMI(electro-magnetic interference) test and an EMS (electro-magnetic susceptibility) test. We investigated the susceptibility test method suggested in KMVSS (Korean Motor Vehicle Safety Standard) as the EMS test method. A series of experiments results that the above test method should be partially revised to comply with a Korean governmental standard method. In this paper, the some directions of modifications are presented to enhance the quality of the above EMS test method.

• Transactions of the Korean Society of Automotive Engineers
• /
• 제21권5호
• /
• pp.151-156
• /
• 2013

The experiment was done on cars travelling at the speeds of 20km/h, 60km/h and 100km/h using the performance testing mode for chassis dynamometer. In this experiment, the relativity between the secondary waveform coming from ignition coil and exhaust emissions were measured in case of cars with failures, in oxygen sensor, spark plugs. The following results obtained by analysis of the relativity between the secondary waveform and exhaust emissions. 1) When the oxygen sensor is failure, the average value of CO emission measured was 6.8 times higher than the standard CO emission value and the average value of HC emission measured was 2.3 times higher than the standard emission level. 2) When engine parts are in failure, more fuel enters the cylinder due to longer opening duration of injector, and it tended to make CO and HC emission values increase. 3) Combustion duration, the shape of flame propagation during spark line, and the size of the discharge-induced energy were the three main elements that directly cause variations in CO and HC emission values.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 한국소성가공학회 2009년도 춘계학술대회 논문집
• /
• pp.187-190
• /
• 2009

Recently, automotive companies have invested in vehicle weight reduction and clean car development because of oil price rises and environmental problems. In particular, USA car makers have developed the vehicle spending 1 liter per 34km complying with PNGV(Partnership for a new generation of vehicle) and Europe car makers have developed the vehicle spending 3 liters per 100km. The USA government announced "The green car policy" in order to boost production of more fuel effective cars in 2009. According to the policy, it will be restricted to sell the car which spends more than 1 liter per 14.9km by 2020. To satisfy the current situations on automotive market, hydroforming technology has widely adapted vehicle structures such as engine cradle, chassis frame, A pillar, radiator support, etc. However, automotive companies have to consider formability and performance to improve and maximize the benefit from this technology in advance of detail design. The paper deals with one of the vehicle weight reduction methods using tube hydroforming technology and platform commonality in front suspension. FEA simulation is also introduced to evaluate hydro-formability and NVH performance at the beginning of design stage which is the best way to reduce the failure cost.

• Journal of Welding and Joining
• /
• 제31권4호
• /
• pp.1-6
• /
• 2013

Nowadays, the weight lightening of automotive is required as conserving the environment has become a major worldwide issue. To solve this issue, various researches for the use of light materials(Alalloy, Mgalloy)and ultra high strength steel as substitutes of the current structural material have been carried out. Application of laser stitch welding to the assembly of automotive produces improvement in strength, lightening of body, higher fuel efficiency, lower production cost as well as reduction in assemble line due to its fast welding speed, superior accessible and weld quality. This process overcomes the shortcomings of the current resistance spot welding such as high electricity consumption, electrode replacement, and economical, technical limitation in design and production method of automotives.