• Title/Summary/Keyword: Heavy Duty

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Shear Strength of Single Anchors in Uncracked and Unreinforced Concrete (비균열·무근콘크리트의 단일앵커 전단내력 평가)

  • Kim, Sung-Yong;Kim, Kyu-Suk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.4
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    • pp.171-181
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    • 2003
  • This study concerns the prediction of shear capacity, as governed by concrete breakout failure, concrete pryout failure and steel failure, of single anchors located close to free edge and located far from a free edge and installed in uncracked, unreinforced concrete. For this purpose, the methods to evaluate the shear capacity of the single anchors in concrete are summarized and the experimental data are compared with capacities by the two present methods: the method of ACI 349-90 and concrete capacity design (CCD) method.

Evaluation of the cavitation effect on liquid fuel atomization by numerical simulation

  • Choi, Sang In;Feng, Jia Ping;Seo, Ho Suk;Jo, Young Min;Lee, Hyun Chang
    • Korean Journal of Chemical Engineering
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    • v.35 no.11
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    • pp.2164-2171
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    • 2018
  • Heavy duty diesel vehicles deteriorate urban air quality by discharging a large volume of air pollutants such as soot and nitrogen oxides. In this study, a newly introduced auxiliary device a fuel activation device (FAD) to improve the combustion efficiency of internal engines by utilizing the cavitation effect was closely investigated by the fluid flow mechanism via a numerical analysis method. As a result, the FAD contributed to fuel atomization from the injection nozzle at lower inlet pressure by reducing the pressure energy. The improved cavitation effect facilitated fuel atomization, and ultimately reduced pollutant emission due to the decrease in fuel consumption. The axial velocity along the flow channel was increased 8.7 times with the aid of FAD, which improved the primary break-up of bubbles. The FAD cavitation effect produced 1.09-times larger turbulent bubbles under the same pressure and fuel injection amount than without FAD.

Optimization of Diesel Engine Performance with Dual Loop EGR considering Boost Pressure, Back Pressure, Start of Injection and Injection Mass (과급압력, 배압, 분사 시기 및 분사량에 따른 복합 방식 배기 재순환 시스템 적용 디젤 엔진의 최적화에 대한 연구)

  • Park, Jung-Soo;Lee, Kyo-Seung;Song, Soon-Ho;Chun, Kwang-Min
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.5
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    • pp.136-144
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    • 2010
  • Exhaust gas recirculation (EGR) is an emission control technology allowing significant NOx emission reduction from light-and heavy duty diesel engines. The future EGR type, dual loop EGR, combining features of high pressure loop EGR and low pressure loop EGR, was developed and optimized by using a commercial engine simulation program, GT-POWER. Some variables were selected to control dual loop EGR system such as VGT (Variable Geometry Turbocharger)performance, especially turbo speed, flap valve opening diameter at the exhaust tail pipe, and EGR valve opening diameter. Applying the dual loop EGR system in the light-duty diesel engine might cause some problems, such as decrease of engine performance and increase of brake specific fuel consumption (BSFC). So proper EGR rate (or mass flow) control would be needed because there are trade-offs of two types of the EGR (HPL and LPL) features. In this study, a diesel engine under dual loop EGR system was optimized by using design of experiment (DoE). Some dominant variables were determined which had effects on torque, BSFC, NOx, and EGR rate. As a result, optimization was performed to compensate the torque and BSFC by controlling start of injection (SOI), injection mass and EGR valves, etc.

Comparison of characteristics between cam and electric control type of 2 stroke diesel engine for ship propulsion (캠 및 전자제어식 선박추진용 저속 2행정 디젤엔진의 성능 비교)

  • Lee, Sang Deuk;Jung, Suk Ho;Koh, Dae Kwon
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.8
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    • pp.849-854
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    • 2013
  • Many researches on green ship with increasing on economics, efficiency and convenience have been carried out consistently. One of them is development of diesel engines with electronic control. While small duty one for automobiles had been adopted mainly already, disseminating heavy duty one for ships has trouble due to safety and reliability. In order to solve these problem in this study, performance of electronic control and cam type engine installed in parallel on training ship HANBADA of korea maritime university was analyzed and compared. It is certain that specific fuel oil consumption of the electronic control type is lower than cam type and excellent at lower engine load, especially. And the electronic control type shows more effective characteristic at sea trial on specific fuel oil consumption.

Evaluation of On-Road NOx Emission from a Light Duty Diesel Vehicle using a Portable Emissions Measurement System (이동식 배출가스 측정장비를 이용한 소형 경유 자동차의 실도로 질소산화물 배출특성 분석)

  • Lee, Tae-Woo;Lee, Jong-Tae;Kim, Jeong-Soo
    • Journal of Korean Society for Atmospheric Environment
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    • v.28 no.1
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    • pp.94-104
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    • 2012
  • The purpose of this research is to quantify the compliance of on-road emission from a light duty diesel vehicle, based on a comparison to emission regulation standard. $NO_x$, CO and THC emissions were measured using a portable device on a selected real-world driving route with a length of approximately 22 km. On-road measurements were repeated by 10 times on a same route to reflect variability in traffic conditions. A test route was divided into 22 road links with length of 1 km to analyze emission results with higher spatial resolution. The average emissions of $NO_x$, CO and THC over total travel distance, which is approximately 220 km, were quantified to be in compliance with emission regulation standards. Under higher spatial resolution, $NO_x$ concentration exceeded a standard in 92 links out of 220 links. The extended time in stop period and the stop-and-go driving cycle were identified as two important reasons for increased $NO_x$ emissions in observed cases. Heavy traffics showed higher $NO_x$ emissions than free flow. These results indicate that the real-world vehicle emissions might exceed the compliance level associate with traffic conditions. Another interesting observation of this research is that the on-road emission characteristics can be independent to the average speed of road links with higher spatial resolution. Variability in on-road emission might not be fully described by solely relying on an average speed, because variability in traffic conditions and road conditions can influence on real-world vehicle emissions.

Accident Models of 4-Legged Signalized Intersections by Vehicle Type in the Case of Cheongju (4지 신호교차로 차종별 사고모형 -청주시를 사례로-)

  • Park, Byung-Ho;Park, Gil-Soo;In, Byung-Chul
    • International Journal of Highway Engineering
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    • v.10 no.4
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    • pp.161-170
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    • 2008
  • This study deals with the accident models by vehicle type. The goal is to develop the accident models by vehicle type using the data of 143 4-legged signalized intersections in Cheongju. In pursuing the above, this study gives the particular attentions to explaining the relationships between the values of EPDO(equivalent property damage only) and the traffic and geometric elements. The main results analyzed are the followings. First, 6 negative binomial models are developed, which are all significant at the 90% confidence level. Second, the values of ${\rho}^2$ by vehicle type are 0.14307(auto), 0.35556(large van), 0.21684(small van), 0.205152(motocycle), 0.32338(light-duty truck) and 0.29046(heavy-duty truck), that are all analyzed to be statistically significant. Finally, the common variable included in all models is ADT(average daily traffic), and the specific variable(SV) of auto is analyzed to be the sum of lane width of main road, SV of large van is the average yellow time, and SV of small van is the difference in the number of lane between main and minor road.

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Understanding Pollutant Emission in a Heavy-Duty Diesel Engine with JP-8 and Diesel (대형 디젤 엔진에서 JP-8 과 디젤 적용 시의 배기 배출물 특성에 대한 이해)

  • Lee, Jin-Woo;Bae, Choong-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.12
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    • pp.1375-1381
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    • 2011
  • Combustion processes in an optically-accessible single-cylinder heavy-duty diesel engine equipped with a highpressure common-rail injection system were investigated for JP-8 and diesel. Direct imaging and two-color thermometry were employed to verify the emission trend for both fuels. The combustion process was characterized by image analysis with focus on luminosity. The results of two-color thermometry were analyzed on the basis of the flame temperature and KL factor distribution. Analysis of the combustion process by direct imaging showed that the ignition delay was longer for JP-8 than for diesel, while the flame was extinguished rapidly. Analysis of the flame luminosity showed that the combustion intensity was higher for diesel and that the flame lasted for a longer duration in this case. Two-color thermometry results showed that the high-temperature region extended over a large area during JP-8 combustion, implying the formation of a large amount of $NO_x$. In addition, the KL factor showed low level over a large area and relatively homogeneous in the case of JP-8 combustion, which implied that less smoke was produced when using this fuel.

A Study on the Emission and Particulate Matter of a Heavy Duty Natural Gas Engine According to Gas Composition under certification tests (인증시험 조건에서 가스조성 변화에 따른 대형 천연가스 엔진 배기가스 및 입자상 물질 배출 특성에 관한 연구)

  • Choi, Ji-Seon;Park, Cheol-Woong;Jang, Hyoung-Jun;Kim, Chang-Gi
    • Journal of the Korean Institute of Gas
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    • v.25 no.6
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    • pp.66-73
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    • 2021
  • In this study, The full load test and WHTC mode test were performed to examine the effect on a heavy duty natural gas engine according to the type of standard gas for certification to check engine performance and exhaust characteristics. Two types of standard gas (Gr, G23) and commercially available natural gas were applied as the fuel used. As a result of the test results of three natural gases with different fuel compositions, G23 with a high nitrogen content was inferior in torque, fuel consumption, and thermal efficiency conditions. In addition, when evaluated in the WHTC mode it was possible to obtain a result that satisfies the EURO VI regulation. However, compared to the other two fuels, the emission characteristics of G23 decreased CO2 and CO, but increased CH4, NOx and PN emissions.

A Comparative Study on Fuel Consumption Depending on The Use of Lift Axle (가변축 사용여부에 따른 연료소모량 비교 연구)

  • Oh, Ju-Sam;Eo, Hyo-Kyoung
    • International Journal of Highway Engineering
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    • v.13 no.3
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    • pp.185-193
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    • 2011
  • As a Lift axle is an additional axle installed mostly in heavy freight truck, It"s introduced for the purpose of cost saving, such as logistics, fuel, tire wear and prevention of the pavement damage. However, the Effects of a lift axle are anecdotal and they have occurred often that a lift axle is used improperly by expectations of some drivers. For these reasons, this study conducts a field experiment in order to identifying the change rate of fuel consumption due to an a Lift axle using, develops the fuel consumption model of field data, and then compares the effects of a Lift axle using through application of the model. As a result, fuel consumption decreased in loading conditions that are both empty and full when not using a lift axle.

New Weight-reduction Design of the Fifth Wheel Coupler with a Trailer by Using Topology Optimization and Durability Tests (위상최적설계를 통한 트레일러 제5차륜 연결구조물의 경량화 및 내구성)

  • Kim, Cheol;Lee, Seung-Yoon;Lee, Yong-Choon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.2
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    • pp.137-143
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    • 2016
  • The fifth wheel coupler is a heavy automotive coupling structure which connects a tractor and a trailer used for heavy-duty trucks widely. It is subjected to various loads simultaneously such as rolling, pitching and yawing loads as well as coupling frictional and impact loadings. Most of existing couplers have been overdesigned and, therefore, it is necessary to reduce the dead weight to increase the fuel efficiency. The topology optimization was applied in order to find conceptual layout designs which could show major load paths and ribs locations, and then the size structural optimization was performed in order to determine the heights and thicknesses of coupler ribs with the predetermined various loading conditions for the development of a new slim coupler with a minimum weight and high enough strength and stiffness. As the results of the topology optimum design, an efficient new coupling structure for truck trailers was designed. The weight of the new fifth wheel coupler was reduced by 4.9 %, compared with the existing one, even though all strength requirements were satisfied. The fatigue test of the new coupler was performed with cyclic vertical loads (+78.4 to +235.2 kN) and horizontal loads (-91.2 to +91.2 kN) simultaneously at 1 Hz and the life of 2,000,000 cycles were achieved without failure.