• Title/Summary/Keyword: Idling rpm

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An Experimental Study on Relationship of the Engine rpm and the Strength of Electro-magnetic Waves in the Engine Room (엔진 회전수와 엔진룸 내의 전자파 세기의 관계에 대한 실험적 연구)

  • Choe, Gwang-Je
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.3
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    • pp.112-118
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    • 2006
  • In this paper, we presented experimental data of the strength of the electro-magnetic waves in the engine room of automobiles. Measured frequency ranges are $145{\sim}380MHz$ and $844{\sim}1044MHz$. Experimental studies are conducted by measuring the radiated power of the frequency spectrum for above frequency bands. The $\lambda/2$ dipoles used for measurement are fabricated to comply with the COMMISSION DIRECTIVE 95/54EC. Experimental results confirm that the level of radiated power in the engine room at idling rpm is about 3dB higher than that of 1500rpm.

Reduction of Power Consumption for Constant Pressure Control of Variable Swash Plate-type Piston Pump by Varying the Pump Speed (가변 용적형 사판식 피스톤 펌프의 회전 속도 조절에 의한 정압 제어 소비 동력 절감)

  • Kim, J.H.;Hong, Y.S.
    • Journal of Drive and Control
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    • v.11 no.4
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    • pp.53-60
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    • 2014
  • This paper proposes a control scheme to reduce the power consumption of a variable displacement swash-plate type piston pump supplying oil to a valve-controlled hydraulic cylinder at constant pressure. Whenever flow rate demand was absent, the swash plate angle and the pump speed were changed to the minimum values required to compensate for the internal leakage flow. In response to command signals, the pump speed was changed in proportion to the absolute mean value of the speed component for position commands. At the same time, a pressure regulator was activated to maintain constant system pressure by precisely adjusting the pump speed with the swash plate angle fixed at the maximum. The conventional system consisting of a pressure-compensated variable displacement type pump is driven at a constant speed of 1,800rpm. By comparison, computer simulation and experimental results showed that idling power at stand-by status could be reduced by up to 70% by reducing the pump speed from 1,800rpm to 300rpm and the swash plate angle to the minimum.

Hybrid control of the swash plate-type variable displacement hydraulic piston pump for an EHA (EHA용 가변용적형 사판식 유압 피스톤 펌프의 하이브리드 제어)

  • Kwon, Yong-Cheol;Hong, Yeh-Sun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.4
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    • pp.291-298
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    • 2013
  • In this paper a new hybrid-type control system is proposed which reduces the pump speed of an electro-hydraulic actuator consisting of a pressure-compensated variable displacement piston pump and a valve-controlled hydraulic cylinder, whenever the flow rate demand is low. In order to avoid interfering with the pressure regulator which also has an effect on swash plate angle, the pump speed is changed in proportion to the mean value of the speed component of position commands. Additionally a pressure switch is employed to prevent the system pressure from getting lower than a reference value. Based on computer simulation & experimental results, it is shown that the hybrid control can save the idling power up to 44% at a stand-by mode by reducing the pump speed from 1,800 rpm to 600 rpm without affecting the dynamic response of the electro-hydraulic actuator.

A study on the identification of noise sources of the 4-cylinder gasoline engine by using acoustic intensity method (음향인텐시티법을 이용한 4기통 가솔린 엔진의 소음원 검출에 관한 연구)

  • Oh, J. E.
    • Journal of the korean Society of Automotive Engineers
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    • v.11 no.1
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    • pp.57-67
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    • 1989
  • Acoustic intensity method is applied to a 4-cylinder gasoline engine in order to identify the noise sources and the response characteristics. Acoustic intensity is analyzed by 1/3 octave band filter for each center frequency. Radiational characteristics of acoustic intensity at overall and the maximum intensity level are represented by using the contour and three-dimensional plot. It is verified that this method is effective to the assessment of engine noise. It can be found that the maximum intensity is radiated from the front side of the engine under idling condition and the right side of it under 2, 000 rpm running with no loading condition at overall level, and also that the maximum intensity is radiated from the oil pan and the intake and exhaust manifold at the center frequency of 100 Hz.

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Layout of Engine Exhaust System for Low-Noise Idling Condition (공회전 시 저소음화를 위한 자동차 배기계 위치 결정)

  • Choi, Choong-Young;Ih, Jeong-Guon;Kim, Tae-Kyoon;Jang, Seung-Ho;Kim, Hoi-Jeon;Delaigue, Antoine
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.10a
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    • pp.242-243
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    • 2009
  • 배기토출음은 공회전시 발생하는 소음에 큰 영향을 끼친다. 연비를 높이기 위하여 공회전시 RPM을 낮추면 엔진 점화 주파수가 낮아지며, 이 경우 배기계 위치에 따른 음향학적 공명 주파수와 일치하면 배기 토출음의 크기가 증가한다. 따라서 본 연구에서는 공회전시 배기토출음을 줄이기 위해 소음기의 위치와 각 배기관들의 길이를 최적화하였다. 최적화 결과로써 3 가지 배기계 위치를 얻을 수 있었고, 실제 실험과의 비교를 통하여 최적화된 배기계 위치가 그렇지 않은 배기계 위치에 비하여 소음 저감량이 높은 것을 확인하였다.

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A Study on the Active Noise Cancellation System in a Vehicle Cabin Using the Weighting Factors of Control Error Path (제어오차계의 가중치를 이용한 차실내 능동소음제어 시스템 연구)

  • 홍석윤;허현무
    • Journal of KSNVE
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    • v.6 no.6
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    • pp.851-856
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    • 1996
  • The active noise cancellation system showing the effective convergence and stability has been studied by simplifying the controller structures using the weighting factors of control error path to the multi-channel filtered-x LMS algorithm which needs a lot of calculations and the performance has been verified experimentally. Besides, to implement the system performance in a vehicle cabin, experimental work for selecting the suitable numbers and positions of the microphones and speakers was accomplished. Effectively combining a TMS 320C 31 main processor conducting real number calculations and having various functions with other components, the purpose-built system board for active noise cancellation has been designed and with this board, car active noise cancellation system showing maximum stable 10dB noise reduction has been obtained at the car idling conditions above 3000rpm range.

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A Study on the Effect of Valve Timing on the Performance and Idle characteristics of 3-Cylinder LPG Engine (밸브 타이밍 변화가 3기통 LPG 엔진의 성능과 Idle 특성에 미치는 영향에 관한 연구)

  • 이지근;이한풍;노병준
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.3
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    • pp.27-34
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    • 1997
  • The effects of the intake and exhaust valve timing to improve the engine performance in a spark ignition 3-cylinder LPG engine with a closed loop fuel supply system were studied. The engine torque and power have been measured using the 75kW EC-dynamometer while adjusting the optimal fuel consumption ratio with a solen- oid driver. As the results from this experiment, when intake valve opening is $12^{\circ}$ BTDC, intake valve closing is $36^{\circ}$ ABDC, exhaust valve opening is $12^{\circ}$ ATDC, and exhaust valve closing is $36^{\circ}$ BBDC respectively, the best torque characteristics in low and high speeds for a gives engine were obtained. And also we could find that the torque characteristics in low speeds were affected by the timing of exhaust valve open. An increased valve overlap by the EVC delay was ineffectual to the torque characte- ristics improvement in high speeds.

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A Study on the Improvement of Combustion Stability for SI Engine at Idle Operation (SI 기관의 공회전시 연소 안정성 향상에 관한 연구)

  • Lee, J.S.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.6
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    • pp.259-266
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    • 1998
  • In the SI engine, the improvement of combustion stability is important not only for the fuel consumption rate but also for the emission control at idling of engine. Thus the engine speed fluctuation at idle operation mainly comes from cyclic variation of combustion in the SI engine. In this syudy, the improvement of combustion stability for the SI engine at idle condition by the cooling water temperature, duty ratio of ISC, spark ignition timing as well as the reducement of the harmful exhaust gas emission was discussed.

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Mutagenicity of Diesel Exhaust Emission by Micronucleus Test (디젤엔진 배기물질의 변이원성 연구)

  • 임국환;배은상;김영환;김광종
    • Journal of Environmental Health Sciences
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    • v.17 no.1
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    • pp.13-19
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    • 1991
  • Interest in the studies of diesel exhaust emission has been increasing by the expected increase in the use of diesel powered automobiles out of concideration of fuel economy. It was well known that diesel exhaust emission was mutagenic in the bioassay as Ames test. The authors tried to find out the cytogenetic effect of diesel exhaust emission by the operational condition of engine such as speed and load. For the investigation of those effects, 66 male mice of ICR strain were used. The benzene-ethanol extracts of diesel exhaust emission were injected intra peritoneum 25rng/kg and 50mg/kg respectively. To evaluate the cytogenetic effect, mouse bone marrow micronucleus test was carried out. The frequency of micronucleus was different among the various groups according to the operational conditions of engine. The frequency of micronucleus in idling group was the highest of all the groups the subgroup of 50mg/kg showed the rate of 1.30%, 25rng/kg subgroup 0.55%. And the group of 2000rpm with 50% load showed the lowest rate of micronucleus appearance as 0.20% and 0.15%. In general, the frequency of micronucleus was shown higher in propotion to load and was shown inversely proportional to speed.

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Development of DC Controller for Battery Control for Elevator Car

  • Lee, Sang-Hyun;Kim, Sangbum
    • International Journal of Internet, Broadcasting and Communication
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    • v.13 no.2
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    • pp.103-111
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    • 2021
  • Among transport vehicles, Special Vehicles (SVs) are seriously exposed to energy and environmental problems. In particular, elevator cars used when moving objects in high-rise buildings increase the engine's rotational speed (radian per second: RPM). At this time, when the vehicle accelerates rapidly while idling, energy consumption increases explosively along with the engine speed, and a lot of soot is generated. The purpose of this paper is to develop a bi-directional DC-DC converter for control of vehicle power and secondary battery used in an elevated ladder vehicle (EC) used in the moving industry. As a result of this paper, the performance test of the converter was conducted. The charging/discharging state of the converter was simulated using DC power supply and DC electronic load, and a performance experiment was conducted to measure the input/output power of the converter through a power meter. Through this experimental result, it was confirmed that the efficiency was more than 92% in Buck mode and Boost mode at maximum 1.2kW output.