• 대한인간공학회지
• /
• 제32권4호
• /
• pp.389-396
• /
• 2013

Objective: The ride qualities of the six passenger cars were evaluated in 4 subjects on the highway and uneven road. The relation between vibration with driving velocity and driving posture were also investigated separately. Background: Ride comfort plays an important role in the vehicle design. Vibration is the one of the principal components associated with ride comfort. Method: The acceleration of the foot, hip and back were measured using B&K accelerometers in this study. The velocity of the passenger cars was maintained at a constant speed of 80km/h on the highway and 40km/h on the uneven road. For evaluating the effects of driving velocity and driving posture on vehicle's vibration level, separate experiments were performed on the highway with 5 different vehicle speeds and 5 different backrest angles, respectively. Results: The overall ride value of the luxury car showed the best result while the smaller car showed the worst value on the highway. On the uneven road the overall ride value level was increased 75~98%. All the vehicles had the SEAT value less than 1. Faster the velocity lowers the SEAT value. The ride quality in terms of vibration gets worst when the backrest angle increased. Conclusion: The smaller car had a first mode at the higher frequency and showed higher vibration level. SEAT value was mostly affected by the seat property not by vehicle. We ranked the luxury car seat had a best vibration reduction quality than others based on SEAT values. When the driving velocity increased, the overall ride values were increased proportionally and the SEAT values were somewhat decreased. Application: Evaluation of whole-body vibration in the passenger car.

• 한국자동차공학회논문집
• /
• 제22권1호
• /
• pp.148-156
• /
• 2014

The objective of this study is to compare NOx emissions from light duty diesel vehicles measured from on-road tests that conducted under various driving routes and seasonal conditions. We measured real-driving NOx emissions using PEMS, portable emissions measurement system, under the urban, rural and motorway road traffic conditions. On-road tests were repeated at summer, fall and winter season. The accumulated driving distance is more than 1,200 km per each vehicle. Route average NOx emission factors were compared among nine route-season combinations. The emission characteristics of each combinations were investigated using time series mass emission rates and vehicle operation-based emission rates and activities, which is based on U.S. EPA's MOVES model. Most concerned route-season combination is "urban road condition at summer", which shows two to eleven times higher NOx emissions than other combinations. The emission rates and activities under low speed operating conditions should be managed in order to reduce urban-summer NOx. From a NOx control strategy perspective, the exhaust gas recirculation, EGR, is observed to be properly operated under wide range of vehicle driving conditions in Euro-5 vehicles, even if the air conditioner turns on. In high power demanding conditions, the effect of overspeeding could be more critical than that of air conditioner activation.

• 한국분무공학회지
• /
• 제21권4호
• /
• pp.207-213
• /
• 2016

To protect air pollution of urban area from motor vehicles, emission limits for diesel vehicles have been dramatically lowered in short period. But recent studies have shown that on-road NOx emissions of light-duty diesel vehicles are considerably higher than the values measured with laboratory test procedures used for emission certification. To tackle with this issue, Ministry of Environment have a plan to introduce EU RDE-LDV (Real-driving Emission-Light-duty Vehicle) regulation. In this study, 4 Euro 6 diesel vehicles have been tested with the new test procedures published by EU to estimate on-road NOx emissions using PEMS (Portable Emission Measurement System). The results have shown that the requirements of EU RDE-LDV could be met in driving condition of metropolitan area for constitution of test routes and validity of test results. In analysing with Moving Averaging Window method the completeness and normality of test data were validated with the requirement. On-road NOx emissions were quite deviated as test vehicles and higher than the new limit of on-road NOx emission enforced from Sept. 2017, which means that RDE-LDV can effectively reduce NOx emission of diesel vehicles in real driving conditions of Korea.

• 융복합기술연구소 논문집
• /
• 제4권2호
• /
• pp.67-70
• /
• 2014

Recently EU has been recognized that there is a difference of emission quantity between emission certification test mode and real-road driving test. Accordingly the European Commission is currently preparing to require real-road testing as part of the passenger car type-approval process in the EU. vehicle manufacturers from 2017 are expected to test new vehicles not only under laboratory conditions but also on the real-road, using PEMS equipment. Therefore the purpose of this study is to analyze the emission and Fuel Economy of CVS-75 mode test using chassis dynamometer and RDE test using PEMS equipment by PHEV passenger car.

• 한국자동차공학회논문집
• /
• 제10권5호
• /
• pp.9-14
• /
• 2002

The durability prediction of emission control components, especially 02 sensor and catalytic converter, is getting more important as emission regulation is getting stricter and vehicle durability mileage requirement is also extended from 80,000 ㎞ to 160,000 km in Korean market. And the duration of vehicle mileage accumulation to get vehicle exhaust emission deterioration factor for certification is required to be shorter in order to reduce the vehicle development time. Since most of the vehicle emission development tests are done on chassis dynamometer and aging bench by using vehicle aging modes, real road condition and in-use driving patterns must be reflected into them to predict the vehicle emission level and to meet emission regulation especially at high mileage. In order to get the frequent driving pattern of vehicle and the aging characteristic of emission components, a vehicle was tested by changing drivers and driving roads around Seoul. Real road driving patterns were analyzed and compared with those of the certification modes which are well known in automotive industry.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제13권11호
• /
• pp.5299-5320
• /
• 2019

Interest in self-driving vehicle research has been rapidly increasing, and related research has been continuously conducted. In such a fast-paced self-driving vehicle research area, the development of advanced technology for better convenience safety, and efficiency in road and transportation systems is expected. Here, we investigate research in self-driving vehicles and analyze the main technologies of driverless car software, including: technical aspects of autonomous vehicles, traffic infrastructure and its communications, research techniques with vision recognition, deep leaning algorithms, localization methods, existing problems, and future development directions. First, we introduce intelligent self-driving car and road infrastructure algorithms such as machine learning, image processing methods, and localizations. Second, we examine the intelligent technologies used in self-driving car projects, autonomous vehicles equipped with multiple sensors, and interactions with transport infrastructure. Finally, we highlight the future direction and challenges of self-driving vehicle transportation systems.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.612-617
• /
• 2014

It is generally known that the automotive road wheel involves the non-proportional multiaxial loading condition, therefore the measuring dynamic stress and strain in driving state is very important to predict an endurance characteristic of the automotive road wheel. In this study, the ultimate driving test using F1 circuit with respect to 2 kinds of velocity conditions have been carried out in order to measure dynamic stress, strain of the wheel and acceleration of a vehicle. Based on the measured results, the characteristics of dynamic stress generation have been analyzed, and factors which have effect on the dynamic stress generation have been studied.

• 전기전자학회논문지
• /
• 제23권1호
• /
• pp.342-345
• /
• 2019

자율주행자동차는 기술적 측면에서 많은 발전이 이루어져왔으나 자율주행자동차의 상용화가 가능하도록 다양한 법적 문제를 해결하는 작업은 매우 더디게 진행되고 있다. 본 논문에서는 자율주행자동차에서 대표적인 법적 이슈인 도로 주행 근거를 분석하고 현행 법/규정상의 문제점을 파악하며 이에 대한 개선 방안을 제시한다. 자율주행자동차에서 기술 개발과 법/규정 정비는 상호 협력적으로 이루어져야 하며, 이러한 법적 이슈를 이해하는 것은 자율주행자동차를 개발하는 기술자에게도 큰 도움이 될 것으로 여겨진다.

• 디지털융복합연구
• /
• 제17권11호
• /
• pp.207-213
• /
• 2019

대부분의 차량에 적용되어 있는 연료차단(fuel-cut) 관성주행은 변속기어 체결 상태에서 가속페달을 방치할 때 자동으로 작동하게 된다. 이 때 연료분사가 일시적으로 중단되므로 연비 향상 효과가 상당하다. 본 연구에서는 GPS를 이용하여 측정된 차속, 가속도, 도로구배 등의 신호를 바탕으로 하는 연료차단 관성주행 감지법을 제안하였다. 관성 주행시 작용하는 주행저항력에 의해 계산되는 가속도값과 GPS에서 실시간으로 측정되는 가속도값을 비교하는 방식이다. 실도로 주행 데이터를 측정하여 이 감지법을 평가한 결과 약 80% 수준의 정확도를 얻을 수 있었다. 도로구배가 다소 큰 12km 정도의 국도를 16분 동안 주행하면서 측정한 약 9,600개의 속도, 가속도, 도로구배 및 연료소모량 데이터에 감지법을 적용하여 얻은 결과이다. 인젝터 분사파형 분석을 위한 배선작업 등이 불필요하여 간단하게 연료차단여부를 판정할 수 있는 장점이 있다. 다만, 속도, 가속도 및 도로구배의 변화율이 연료소모량의 변화율에 비해 훨씬 크게 나타나기 때문에 감지법의 오차도 다소 증가하는 것을 알 수 있었다.

• 한국자동차공학회논문집
• /
• 제3권2호
• /
• pp.1-15
• /
• 1995

The driving patterns in Seoul metropolitan area were surveyed in an experiment involving 1,212km of driving along seventeen representative routes. The speed and fuel consumption data were recorded and the influence of driving patterns on vehicle fuel economy was analyzed by statistical techniques. The results showed that characteristics of driving in Seoul metropolitan area are far different from that of CVS-75 mode and then on-road fuel economy in Seoul may be small as compared with that of CVS-75 mode. Finally, it was proposed that CVS-75 mode fuel economy should be modified by applying adjustment factor to represent actual on-road fuel economy.