• Applied Chemistry for Engineering
• /
• v.31 no.3
• /
• pp.338-340
• /
• 2020

Sericite is used as a raw material for ceramics and paints, and recently it is widely used as adsorbents to remove heavy metals in wastewater. A new air filter containing sericite was developed using the principle of which components contained in the sericite react with moisture in the air to release oxygen. We tested whether the newly developed air filter actually improves fuel efficiency when mounted on a diesel vehicle. When the diesel vehicle used in the test was warmed up, the fuel efficiency increased by 10~17% compared to when an existing air filter was installed. However, the effect of the developed air filter on the amount of emissions (HC, CO, NOx) has not been investigated, and further research is required for the diesel vehicle emissions.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.40 no.11
• /
• pp.963-970
• /
• 2016

This research deals with design and performance validation of eco-pedals that generate tactile pedal force to guide fuel saving driving behavior. For eco-pedal control logic, allowable fuel consumption at given driving speed is calculated based on pre-defined "allowable acceleration", and if the actual fuel consumption exceeds the allowable fuel consumption, then pedal force is activated. Pedal force should be recognizable to driver while not causing unpleasantness, and should not interfere with normal operation of pedal. Reaction forces that increase pedal stiffness abruptly, such as step and ramp shape, turn out to be not suitable due to pedal overshoot after release of reaction force. With this regards, vibration type reaction force is adopted, and its optimal frequency, magnitude and duration is determined through subjective evaluation with consideration to effect to fuel efficiency. Though highway and city driving test, it is demonstrated that fuel efficiency increase of 13% for highway and 15% for city is achieved.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.2
• /
• pp.689-694
• /
• 2018

Recently, fuel consumption efficiency has become the most important issue in the vehicle development process due to the problem of environmental pollution. The air flow patterns of the vehicle body line and rear part are the most important elements affecting the fuel consumption efficiency. Especially, the airflow pattern of the vehicle rear part is the most important design factor to be considered in rear spoiler design. In this paper, the control factors affecting the airflow of the rear spoiler are determined, the airflow sensitivity of these control factors are tested and, then, the optimized control factors to reduce the airflow drag force are proposed. The model of optimized control factors is tested and the values of the optimized control factors are changed by analyzing the S/N ratio and mean value. Finally, the new modified model incorporating the optimized control factors is tested in an air flow tunnel and its ability to decrease the air drag and reduce the cost is verified.

• Applied Chemistry for Engineering
• /
• v.31 no.3
• /
• pp.310-316
• /
• 2020

Terpene-modified phenolic resins were used to improve the tires wet traction related to the driving safety and also rolling resistance related to fuel efficiency. In this work, alpha-pinene, beta pinene, and delta limonene resins, which constitute different basic structures of terpene-modified phenolic resins, were individually added to the tread compounds of tires and their physical properties were compared with those of the alkyl phenol resin compounds. Alkyl phenolic resins showed no significant difference in tangent delta from terpene-modified phenolic resins at 0 ℃, which is related to wet traction, but showed higher tangent delta at 80 ℃, which is related to rolling resistance, indicating smaller fuel efficiency improvement effects. Among the terpene-modified phenolic resins, beta pinene one showed improved wet traction and fuel efficiency compared to those of other resins. Delta limonene resin showed the best wet traction improvement effect, and alkyl phenolic resins showed relatively high tensile strength and abrasion property. All terpene-modified resins exhibited better rolling resistance than those of alkyl phenolic ones so that they can be said to have better fuel efficiency improvement effects and also to improve other properties compared to those of blanks. Terpene-modified phenolic resins could be used when mixing tire compounds referring to the properties of the phenolic resins revealed in this work, which could result in preparing compounds with improved wet traction and rolling resistance.

• Transactions of the Korean hydrogen and new energy society
• /
• v.28 no.3
• /
• pp.287-294
• /
• 2017

EVs manufacturers typically target a range of 300 km on a fully charged battery. Many studies have been conducted to improve these disadvantages. As a results, the mileage of EVs is expected to increase significantly. However, as the distance traveled by EVs increases, current test method (SCT) have many difficulties. The biggest problem is that it takes a lot of time to test an EVs and greatly increases the error rate during the test period. In order to solve these problems, this paper discusses the fuel economy test method of EVs for energy efficiency and mileage. The comparison of test methods was achieved by chassis dynamometer test about EVs. These review of test methods are intended to both improve testing efficiency and provide a practical testing methodology that can be easily adapted to accommodate future testing enhancements. In conclusion, the results of MCT mode and SCT mode comparison show similar results within 3 %, confirming that the test method is appropriate. Also, as the CSCM distance becomes shorter in the MCT mode, the mileage becomes longer and the fuel economy becomes lower. As a result, the error from the SCT test results is expected to increase. In order to minimize the error of SCT measurement fuel economy, it is recommended to maximize the CSCM driving distance. However, since the timing of the EOT is not clearly known, it is reasonable to define the allowable range of the CSCE to be within 20 % of the MCT total mileage.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.1
• /
• pp.457-467
• /
• 2020

Increasing environmental concerns have prompted countries around the world to tighten regulations on greenhouse gases and fuel efficiency. Research is being done using advanced driver assistance systems to improve fuel economy and for the convenience of drivers. Research on systems such as adaptive cruise control (ACC), LKAS, and AEB is active. The purpose of ACC is to control the longitudinal speed and distance of the vehicle and minimize the driver's load, which is considered useful for accident prevention. From this point of view, research has used a mathematical method of safety evaluation as a function of distances and scenarios while considering domestic road environments. A vehicle is tested with a simulation in a proposed scenario. The purpose of the analysis is to verify the functional safety of ACC by comparing the theoretical calculations using theoretical equations, the relative distances in the simulation, and an actual vehicle test. These methods are expected to enable many companies to use scenarios, formulas, and simulations as safety verification methods in the development of ACC.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.9
• /
• pp.133-140
• /
• 2016

The Ministry of Land, Infrastructure and Transport has introduced low-floor buses, which are convenient for passengers getting on and off the bus and for the handicapped. The standard bus model is 11 m long and uses compressed natural gas (CNG). However, this model has drawbacks in narrow rural road conditions such as those in farming and fishing villages and mountainous areas, as well as difficulty in refueling since CNG facilities are not readily available. In this study, running resistance values were obtained by coasting performance tests on actual roads using a Tata Daewoo LF-40 model with three different weight conditions: curb vehicle weight (CVW), half vehicle weight (HVW), and gross vehicle weight (GVW).The test methods include WHVC, NIER-06, and constant-speed driving at 60 km/h. These tests were used to measure the fuel economy of vehicles other than the target vehicles to obtain the combined fuel economy. The energy efficiency was highest in the case of CVW. In the WHVC mode, the fuel consumption rates of HVW and GVW were typically 3.5% and 12% higher than that of CVW, respectively. In constant-speed driving, the fuel efficiency of HVW was higher than that of CVW. Further research is required to analyze the exhaust gas data.

• Journal of Energy Engineering
• /
• v.25 no.4
• /
• pp.159-169
• /
• 2016

In this study, the effects of MTBE contents as oxygenates in gasoline on exhaust emissions and fuel economy in MPI and GDi vehicles have been investigated. Various oxygen contents have been selected such as 0, 1.0, 2.3 and 2.7 wt%. FTP-75 and HWFET modes as fuel economy test methods which are widely used in Republic of Korea and US were applied to investigate exhaust emissions from the test vehicles. Emissions of CO, NMHC and NOx did not show significant correlation with oxygen contents in gasoline fuels, although having slight difference with these contents. In addition, CO2 emissions were not significantly changed with respect to oxygen content. But in case of warm-up and FTP-75 and HWFET modes including high speed regimes, CO2 emissions showed inverse correlation with oxygen contents. Particulate number concentration was inversely proportional to the oxygen contents, having the minimum value at the condition of 2.3 wt%. In case of fuel economy through carbon balance method, the highest value has been obtained at 2.3 wt% and there was positive correlation with oxygen contents and fuel economy.

• Journal of the korean Society of Automotive Engineers
• /
• v.9 no.5
• /
• pp.25-33
• /
• 1987

최근 저연비 및 차실내거주성향상의 관점에서 볼 때 소형차의 대부분이 FR에서 FF방식으로 바뀌며 차체의 경량화가 적극적으로 추진되고 있다. 본문에서는 수평식엔진 FF차(4기통, 4cycle엔진)에 관해 공회전시 진동과 급가속시의 쇼크진동 (shock vibration)을 중심으로 차체진동을 시험, 해석하고 이에 관련한 각각의 요소들을 총괄적으로 검토함으로써 차체나 엔진지지부의 합리적인 설계를 하는데 필요한 것들을 검토하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2017.05a
• /
• pp.139-139
• /
• 2017

최근 환경오염 문제로 인한 연비 규제 강화 속도가 빨라지고 있으며 이에 따른 연비 향상 기술이 크게 대두 되고 있다. 연비 향상 기술 중 경량화 방안소재로 알루미늄(Al), 마그네슘(Mg) 등의 비철금속을 주로 사용하고 있으며, 이중 알루미늄은 다른 경량화 금속소재보다 우수한 경쟁력을 가지고 있다. 하지만 경제적인 측면에서 철 대비 비용적인 어려움을 가지고 있고 용접성이 떨어지기 때문에, 자동차 부품의 일부만 알루미늄 소재를 선택하여 사용하고 있는 실정이며 알루미늄의 높은 이온화 경향으로 인해 기존 자동차 철강 소재와 접촉 시 쉽게 부식되는 단점을 가지고 있다. 이러한 문제점을 해결하기 위해서는 알루미늄의 금속원소를 첨가하는 연구가 지속적으로 개발 되고 있다. 알루미늄 합금에서 마그네슘의 첨가는 좋은 용접성과 내식성, 강도를 향상시킨다. 하지만 3%이상의 마그네슘 첨가는 입계에 ${\beta}(Al_xMg_y)$석출상이 석출되게 되며, 입계에 연속적으로 형성된 ${\beta}(Al_xMg_y)$석출상은 응력 부식 균열 (Stress corrsion cracking)과 입계 부식(Intergranular corrosion)을 야기하는 결과를 가져온다고 알려져 있다. 이 문제를 해결하기 위해 Al 5000계열 합금의 Zn의 첨가를 통해 ${\tau}(Al_xMg_yZn_z)$을 입계에 석출시켜서 입계에 ${\beta}(Al_xMg_y)$상의 석출을 방지함으로써 내식성을 향상시키거나 Al 5000계열 합금의 열처리를 통해 ${\beta}(Al_xMg_y)$석출상을 고용시킴으로써 응력부식균열의 발생을 억제하는 연구도 있다. 하지만 열처리 후 Polarization test를 이용한 내식성 연구는 잘 안 알려져 있다. 따라서 이번 연구에서는 Al5000계열의 주조한 합금을 DSC분석을 통하여 ${\beta}(Al_xMg_y)$석출상의 고용 온도가 약 $470^{\circ}C$라는 것을 확인한 후, 실온에서 $100^{\circ}C/hr$으로 가열하고 조건에 따라 $450^{\circ}C$에서 3시간, 6시간, 12시간, 24시간, 30시간 항온 유지시킨 후 공냉을 진행하였다. 열처리를 마친 시편은 에폭시를 이용하여 마운팅 하였으며, 시편표면을 2000#까지 연마 후 증류수로 세척한 다음 질소를 이용하여 건조 후 분극 시험을 진행하였다. 3.5wt% NaCl 용액에서 분극 곡선을 통해 부식거동을 확인한 결과 24시간까지 시간이 증가 할수록 내식성이 우수해지는 것을 확인하였으며, 추가적으로 조직사진, SEM & EDS 분석과 XRD, TEM 분석을 통해 내식성은 입계에 존재하는 Mg의 조성이 감소하게 되면 내식성이 향상되는 것을 관찰하였다.