• Title, Summary, Keyword: Engine speed

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The Research about Engine Speed change Effect on HCCI Engine Combustion by Numerical Analysis (엔진회전속도의 변화가 HCCI엔진연소에 미치는 영향에 관한 수치해석 연구)

  • Lim, Ock-Taeck
    • Journal of ILASS-Korea
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    • v.16 no.3
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    • pp.126-133
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    • 2011
  • In HCCI Engine, combustion is affected by change of compression speed corresponding to engine speed. The purpose of this study is to investigate the mechanism of influence of engine speed on HCCI combustion characteristics by using numerical analysis. At first, the influence of engine speed was shown. And then, in order to clarify the mechanism of influence of engine speed, results of kinetics computations were analyzed to investigate the elementary reaction path for heat release at transient temperatures by using contribution matrix. In results, as engine speed increased, in-cylinder gas temperature and pressure at ignition start increased. And ignition start timing was retarded and combustion duration was lengthened on crank angle basis. On time basis, ignition start timing was advanced and combustion duration was shortened. High engine speed showed higher robustness to change of initial temperature than low engine speed. Because of its high robustness, selecting high engine speed was efficient for keeping stable operation in real engine which include variation of initial temperature by various factors. The variation of engine speed did not change the reaction path. But, as engine speed increased, the temperature that each elementary reaction would be active became high and reaction speed quicken. Rising the in-cylinder gas temperature of combustion start was caused by these gaps of temperature.

Development of the Robust Speed Controller for Marine Medium Speed Diesel Engines (선박용 중속 디젤 기관의 로바스트 속도제어기 개발)

  • 정병건;양주호;김창화
    • Journal of Advanced Marine Engineering and Technology
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    • v.20 no.4
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    • pp.27-35
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    • 1996
  • The ship's propulsion efficiency depends upon a combibation of engine and propeller. The propeller has better efficiency as the engine has lower rotational speed. This situation led the engine manufacures to design the engine that has lower speed, longer stroke and a small number of cylinders. With this new trends the conventional mechanical-hydrualic governors for engine speed control have been replaced by digital speed controllers which adopted the PID control or the optimal control algorithm. But these control algorithms have not enough robustness to suppress the variations of the delay-time and the parameter perturbation especially in low speed engine. In this study we consider the perturbations of the engine parameters as the modeling uncetainties and design a robust speed controller for marine medium speed diesel engine by means of $ extit{H}_{infty}$control theory having the central solution. By comparing the results of the robust speed controller with those of mechanical governor and PID controller, the validity of the robust speed controller under parameter variations is confirmed. The speed control of the experimental diesel engine of carried out using actuator which is composed of PWM signal generator and D.C servo motor.

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Nonlinear Control of Torque and Speed of S.I.Engines Using Electric Throttle Control (트로틀 앵글 제어에 의한 내연기관의 토오크 및 속도의 비선형 제어)

  • 원문철;강병배;박문수;김태영
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.6
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    • pp.72-81
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    • 1999
  • A nonlinear engine torque and speed control algorithm using throttle angle control is developed with an engine load torque estimation algorithm. Three 3-dimensional nonlinear engine maps as a part of the nonlinear control algorithm are obtained from steady state engine dynamometer tests. An electric throttle actuator is developed using a stepper motor and a 8 bit micro-processor. The speed control and external load estimation algorithm are tested via engine speed control experiments, and show performance good enough for using various engine torque and speed control applications.

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A study of the effects of engine speed and load on diesel emissions (엔진속도와 부하가 디젤 배기가스에 미치는 영향에 관한 연구)

  • 이재순;김승무;서정일
    • Journal of the korean Society of Automotive Engineers
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    • v.4 no.2
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    • pp.47-57
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    • 1982
  • Smoke, Hydrocarbon and Garbon Monoxide emissions of concern in environmental pollution on AVDS-170-2D diesel engine were studied experimentally and past studies on emissions of diesel engine were investigate. Engine speed and load were considered as variable factors influencing the emissions. The test results of a multicylinder, direct injection and turblcharged 4 cycle diesel engine were compared with past studies. Both emission levels of experimental study and past studies were markedly influenced by engine operation factors. The results obtained in this study can be summarized as follows; 1) Smoke intensity is proportional to engine load and varies with engine speed. 2) Hydrocarbon and nitric oxides emissions vary with engine speed and load. 3) Garbon monoxide emission is insensitive to engine speed and varies with engine load.

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A Study on the Response Performances under Transient Operating Conditions in a Turlblocharged Diesel Engine (터보과급 디젤기관의 과도운전시 응답성능에 관한 연구)

  • 최낙정;이창식
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.8
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    • pp.1575-1582
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    • 1992
  • This study describes the response performances of actual engine speed, turbocharger speed, air mass flow rate through engine, boost pressure ratio, exhaust temperature and combustion efficiency for a six-cylinder four-stroke turbocharged diesel engine during the change in operating conditions by using the computer simulation with test bed. In order to obtain the transient conditions, a suddenly large load was applied to the simulation engine with the several kinds of inertia moment in turbocharger and engine, and engine set speed. From the results of this study, the following conclusions were summarized The inferior response performances was mainly caused by turbocharger lag, and air mass flow rate and boost pressure ratio were closely related to the turbocharger speed. A reduced moment of turbocharger inertia resulted in less transient speed drop and much faster recovery to the steady state of the engine. The increase of moment of engine inertia reduced cyclic variation of engine speed. When a large load was applied to the engine at high speed, the engine could be fastly recovered. However, when the same load was applied to the engine at low speed, the engine was stalled.

Instantaneous Speed Variation of Crankshaft on a Low Speed Marine Diesel Engine (저속박용디젤기관의 순간회전속도 변동에 관한 연구)

  • Choi, Jae-Sung;Lee, Jin-Uk;Lee, Sang-Dug;Cho, Kwon-Hae
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.2
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    • pp.138-144
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    • 2007
  • The variation of the crankshaft speed in a multi-cylinder engine is determined by the resultant gas pressure torque and the torsional deformation of the crankshaft. Under steady state operation, the crankshaft speed has a quasi-periodic variation. For the diagnosis the engine instantaneous speed versus crankshaft angle is utilized. This paper describes a simple measurement method of the engine instantaneous speed versus crankshaft angle using the teeth on the flywheel of the crankshaft. Two non-contacting magnetic pickup combinations detect the crank angle and TDC position for the data acquisition. The results from experiments on a 6 cylinder marine diesel engine demonstrate that the crankshaft speed variation are detected with good resolution. And the crankshaft speed variation is investigated according to the operation conditions. Also, it is confirmed that the engine output measured by EMS can be evaluated larger than the actual value due to TDC position error caused by instantaneous speed variation.

Methodology of Engine Fitness Diagnosis Using Variation of Crankshaft Angular Speed (엔진 회전속도 변화를 이용한 상태진단 기법에 관한 연구)

  • Lee, Byung-Yeol;Ha, Seung-Jin;Lim, Ock-Taeck
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.11
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    • pp.1529-1535
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    • 2011
  • Improvement of the thermal efficiency in operation and maintenance of low- and medium-speed engines is a kind of never-ending requirement in the maritime power plant business. For the purpose of improving engine management efficiency, a principal factor that represents the fitness of the engine should be identified. Gas pressure, gas temperature, and vibration have all been used as this factor. However, they have limitations in terms of response speed and diagnosis accuracy. The EFR (engine fitness ratio) is suggested as a new diagnostic factor in this paper. The EFR is defined as the ratio of particular frequencies in the frequency domain and represents the fitness of an engine. It is calculated from the fluctuation pattern of the crankshaft angular speed. The EFR was verified using an experimental method for a low-speed engine and an analytic method for a medium-speed engine.

A Study on the Improvement of the Speed Control Performance in a Diesel Engine (디젤기관의 속도제어성능 개선에 관한 연구)

  • 김병덕;하주식
    • Journal of Advanced Marine Engineering and Technology
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    • v.17 no.5
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    • pp.33-43
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    • 1993
  • Recent marine propulsion diesel engines tend to become slower in speed and longer in stroke for the higher engine efficiency, and in these long stroke and slow speed engines the digital governors are highly recommended to be used. But, in the present digital governors only the feedback of the engine rpm-signal is used for the engine speed control and it does not work so effectively when the load variation is large. In this paper, a new method is proposed to improve the speed control performance in a diesel engine, by adding the torque feedback loop to the present digital governor which uses the rpm feedback PID controller only. And also a method is proposed to adjust the parameters of the PID controller optimally.

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A Study on the Optimun Speed Measurement for the Speed Control of a Diesel Engine (디젤기관의 속도제어를 위한 최적회전수 측정에 관한 연구)

  • 유영호
    • Journal of Advanced Marine Engineering and Technology
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    • v.21 no.5
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    • pp.579-583
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    • 1997
  • A diesel Engine rotates vibratively because of alternative explosion strokes. Traditional measurement of a diesel engine speed is carried out by measuring output voltage of FV convertor from input signals of MPU(magnetic pickup unit) or of DC tachometer. Because these measurement include also vibrative rotation of a diesel engine, an analog filter is often used to eliminate high frequency noises due to periodic explosion stroke. But by this method these high frequency noises do not eliminated effectively because noise frequencies are changed according to diesel engine speed. In this paper, author proposes a new measurement method of a diesel engine revolution which read digital signal directly from MPU and prove the utility of proposed method through the real experiment.

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Controller Design for Stable Engine Idle Mode (안정한 엔진 공회전 모드를 위한 제어기 설계)

  • 이영춘;방두열;이성철
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.6
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    • pp.89-95
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    • 2000
  • The engine idle speed mode becomes worse as one drives a vehicle for several years. This is due to ageing of engine and power-train parts. In this case, unstable idle conditions such as engine stall and droop are frequently experienced when the engine gets heavy torque loads due to power steering pump and air conditioning compressor. The objective of this paper is to study on the idle speed control using PID controller under load disturbances. The input of the PID controller is an error of rpm. The output of the PID controller is an ISCV duty cycle. The dSPACE Controller Boards are used to interface with engine. The on-vehicle test is realized using by SIMULINK and BLOCKSETS tools. The real time interface control panel supplied by Control Desk S/W is designed to have good results in engine idle speed control.

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