• Journal of Korean Society of Transportation
• /
• v.29 no.5
• /
• pp.107-120
• /
• 2011

Traffic signal is one of the major factors that affect the amount of vehicle emissions on urban highway. The amount of vehicle emissions in urban area is highly affected by the vehicle's cruising speeds heavily influenced by the traffic signal lighting conditions. It was attempted in this study to trace the changing patterns of the vehicle emissions by collecting the emission data from a set of simulation studies and by categorizing vehicle cruising conditions into four different groups: idling, acceleration, deceleration, and running at a constant speed. Authors propose a simple emission model prepared based on Kinematic theory. The validation test results showed that the amount of the emission estimated by the proposed model was relatively satisfactory compared to the one of the existing model employing the average speed data only as the determinant.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.17 no.1
• /
• pp.19-23
• /
• 2009

This paper focuses on vehicle fuel economy improvement using D-Range neutral control of automatic transmission. The system objected to reducing of fuel consumption during idle. Usually, turbine of conventional auto transmission is mechanically linked to wheel during idling condition. Therefore speed ratio of torque converter is zero for that period. This causes needless power loss by the torque converter slip. To improve this inefficiency automobile makers develops electronically-controlled D-range neutral control system. The D-range neutral control system minimizes slip on the torque converter by shifting gear to a neutral position during vehicle stoped with D-range gear position. However there's insufficient study about the effect of D-range neutral control system on vehicle fuel economy. In this paper, researches are performed on effect of D-range neutral control system on vehicle fuel economy by experiment with two different vehicle. And it is also estimated the effect on vehicle fuel economy using computer simulation. As a result, 1.8% of LA-4 mode fuel economy improvement can be achieved in a vehicle by D-range neutral control system.

• Journal of Power System Engineering
• /
• v.12 no.1
• /
• pp.13-19
• /
• 2008

In this study, a variable induction and exhaust system is applied to turbocharged diesel engine to improve the volumetric efficiency, especially, in a low and transient engine speed range where much of the pollutant matters are expelled out. The volumetric efficiency is known as one of the most important factor which affects significantly engine performance, fuel economy and further emission and noise level. As the torque increase with the engine speed up, the gas flow in an exhaust pipe become pulsating and then has an effect on boost up capacity of air charging into the cylinder and expelling capacity to atmosphere simultaneously. But at a low and idling speed, the pulsation effect was not so significant. Accordingly, resonator was employed to compensate their loss. The variable induction system consists of the secondary pipe, resonator, intercooler, and torque variance were examined with extended operating conditions. In the mean time, for interpretation and well understanding for the phenomena of wave action that arising during intake and exhaust process between turbocharger and variable intake system, the concept of the combined supercharging was introduced. Some of results are depicted which deal with a pressure history during valve events of induction process. Consequently, by the governing of these phase and amplitude of pulsating wave, it enables us to estimate and evaluate for the intake system performance and also, designing stage of the system layout.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.6
• /
• pp.1004-1011
• /
• 2006

In this study, we have performed a systematic case study on troubles and diagnoses of passenger car's engine based on OBD. We have acquired 1,242 data in order to analysis accurate troubles' causes and apposite diagnoses. 128 data of them are got using OBD apparatus, and the rest of them are collected on related website. As results, distribution on trouble cases shows bad idling(32%), poor acceleration(21%), stop in running(19%), faulty start(11%), inferior fuel economy(9%), and insufficient power(8%) in order of magnitude. And in the systematic cases, it is not difficult to detect troubles in a single part. But we know that special apparatus such as multichannel scanner is needed in complicated troubles. Furthermore we think that the survey is continued in various ways for more systematic case study on troubles and diagnoses.

• Journal of Korea Port Economic Association
• /
• v.37 no.2
• /
• pp.19-31
• /
• 2021

This study is aming at analysing the current trend of container shipping industry before and after COVID-19 Pandemic circumstances. Also, this study offers the political implications for 'the Korean Shipping Nation Rebuilding'. As a result of this study, the several global shipping lines have decreased their ship capacity in response to International Maritime Organization(IMO)'s environmental regulation. This finding is differ from the media reports, that is many shipping companies increased idling vessel to match the lower demand induced COVID-19 pandemic. This study also provides the two implications of the direction about Korean shipping policy. The first one is that the casual relationship of over-vessels' supply and Korea shipping policy is needed to be thoroughly analyzed. The importance of Koreans shipping industry is generally devaluated by most citizens so as to the Korean government should develop the mass media contents to enlighten the less wellknown people regarding shipping industry.

• Asian-Australasian Journal of Animal Sciences
• /
• v.32 no.5
• /
• pp.675-690
• /
• 2019

Objective: This study investigated the effect of diet and roughage quality (RQ) on dry matter intake, duration and number of daytime and night-time eating bouts, idling sessions and ruminating activities in small ruminants. Methods: In Exp 1 and 2, RQ was improved by urea treatment of veld hay, while diet quality was improved by supplementing with Lucerne hay (Exp 3), sunflower meal and lespedeza (Exp 4), fish meal (Exp 5a), and sunflower meal (Exp 5b). In all experiments goats and sheep were blocked by weight and randomly allocated to experimental diets. Day-time (06:00 to 18:00 h) and night time (18:00 to 06:00 h) feeding behaviour activities were recorded. Results: RQ affected rumination index in Exp 1, but not in Exp 2, 3, and 5. Time spent eating and ruminating was affected by RQ (Exp 1, 3, and 4), period of day (all experiments) and their interaction (Exp 1). Intake rates (g/bout and g/min) were similar across diets. Period of day affected the duration of rumination sessions (Exp 1, 2, and 3); diet or RQ affected the duration of eating bouts (Exp 3) and rumination sessions (Exp 1 and 2). RQ had a significant effect on the duration of eating sessions in Exp 3 only, whilst period of day affected this same behaviour in Exp 2 and 3. Generally, goats and sheep fed on roughage alone ruminate at night and eat more during the day but those fed a roughage and supplemented with Lucerne hay spent more time ruminating than eating. Time spent eating and ruminating had positive correlations to crude protein and feed intake. Intake rates had strong positive correlations to intake. Conclusion: Chewing time, number of eating and ruminating sessions, and duration of eating bouts are physiologically controlled in small ruminants, though chewing time requires isometric scaling during modelling of intake.

• Journal of Advanced Technology Convergence
• /
• v.2 no.3
• /
• pp.17-24
• /
• 2023

I am designing a research paper with the aim of studying hybrid vehicles. Hybrid vehicles, as the next-generation automobiles, feature a combination of internal combustion engines and battery engines, resulting in a revolutionary reduction in fuel consumption and harmful gas emissions compared to conventional vehicles. The electric motor in hybrid cars derives power from a high-voltage battery installed within the vehicle, which is recharged during vehicle motion. In contrast to traditional cars, which often experience energy losses due to idling caused by traffic congestion, hybrid systems optimize efficiency by skillfully managing the interplay between the internal combustion engine and the electric motor. This approach effectively addresses the inherent drawbacks of gasoline or diesel engines.Hybrid cars offer an array of benefits, including improved fuel efficiency, environmental friendliness, cost-effectiveness, and reduced noise emission. Consequently, they are progressively becoming a favored alternative among a growing number of individuals. This research endeavor has the potential to contribute towards curbing environmental pollution and dedicating efforts to future automotive research.

• Journal of Drive and Control
• /
• v.20 no.3
• /
• pp.15-24
• /
• 2023

The aim of this study was to measure and evaluate the exhaust emission factors of agricultural tractors. Engine characteristics and three exhaust emissions (CO, NO_x, PM) were collected under actual agricultural operating conditions. Experiments were performed on idling, driving, plow tillage, and rotary tillage. The load factor (LF) was calculated using the collected engine data, and the emission factor was analyzed using the LF and exhaust emissions. The engine characteristics and exhaust emissions were significantly different for each working condition, and in particular, the LF was significantly different from the currently applied 0.48 LF. The data distribution of exhaust emissions was different depending on the engine speed. In some conditions, the emission factor was higher than the exhaust emission standards. However, since most emission limit standards are values calculated using an engine dynamometer, even if the emission factor measured under actual working conditions is higher, it cannot be regarded as wrong. It is expected that the results of this study can be used for the inventory construction of a calculation for domestic agricultural machinery emissions in the future.

• Korean Journal of Agricultural Science
• /
• v.50 no.4
• /
• pp.617-628
• /
• 2023

This study aimed to evaluate the engine load factor (LF) of a 90 kW agricultural combine harvester. The combine harvester used in this study is equipped with an electronic engine, and real-time engine data (torque and speed) was collected through a controller area network. The speed of the combine harvester during harvesting operation was divided into three levels (4, 5, and 6 km/h) for the representative operation speed range of 4 to 6 km/h. The LF was calculated using the engine load data measured in real time during harvesting. A weight was applied to the LF for each condition based on a survey of the usage. Results of the field test showed that the LF was 0.53, 0.64, and 0.87 at working speeds of 4, 5, and 6 km/h, respectively. The highest engine load factor was recorded at 6 km/h. Finally, based on the weight for the usage applied, the integrated engine LF was analyzed to be 0.69, which is approximately 144% higher than the currently applied LF of 0.48. A study on LF analysis for the entire work cycle, including idling and driving of the combine harvester, will be addressed in a future study.

• Journal of Korean Society of Transportation
• /
• v.27 no.2
• /
• pp.199-206
• /
• 2009

In relation with economical efficiency analysis on investment evaluation of transportation system, among vehicle operating cost saving benefit that is applied to general preliminary assessment guidelines and investment evaluation guidelines, oil expense calculated data which concentrated and analyze on the relationship between oil consumption amount on running state and running speed. For uninterrupted flow which does not have stopped delay due to traffic signal, consideration for reduction benefit is possible due to the changes of running speed and travel time however, for interrupted flow which the stopping occurs due to signal control on actual signal intersection has no consideration for stopping delay time reduction and stopping rate improvement thus reflection of reality on improved effect analysis is difficult. Therefore, this research makes a framework to analyze benefits that reflects the features of signalized intersections by benefits associated with decrease of stopping delay time with existing research and developing vehicle operating cost calculation model formula. Vehicle operating cost has been redefined considering the stopping delay time by applying the oil consumption amount at idling and the economical benefit between conventional model and newly developed model when applied for the optimization of traffic signal system on the two roads in Seosan city has been analyzed comparative. While the importance of traffic system maintenance is being emphasized due to the increase of congested areas on roads, it is expected to assist in more realistic economical analysis which reflect the delay improvement through the presentation of an economic analysis model that considers the features of signalized intersections in signal optimization system improvements and effect analysis of congestion improvement projects`.