• Journal of Advanced Marine Engineering and Technology
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• 제17권2호
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• pp.29-35
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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. If the load torque of the engine can be measured or estimated and the torque feedback loop is added to the present digital governor, it is expected that the speed control performance of the digital governor will be highly improved. In this paper, a new method is proposed to estimate the load torque of the diesel engine from the measured signals of fuel oil and rpm. And it is also suggested that the Kalman filter can be used for the estimation of engine torque.

• Journal of Advanced Marine Engineering and Technology
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• 제17권5호
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• pp.63-70
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• 1993

In 1980's to 1990's the marine propulsion diesel engines have been developed into lower speed and longer stroke for the energy saving(small S.F.O.C.). As these new trends the convetional mechnical-hydraulic governors were not adapted to the new requirements and the digital governors have been adopted in the marine use. The digital governors usually use the control algorithms such as the PID control, optimal control, adaptive control and etc. While the engine has delay time and parameter variations these control algorithms have difficulty in considering the stability and the robustness for the model uncertainty. In this study, the $H_{\infty}$ controller design method are applied to the speed control of the low speed marine diesel engine. By comparison the $H_{\infty}$ control results with the PID control results, the validity of the $H_{\infty}$ controller under the delay time and parameter variations is confirmed.

• Journal of Mechanical Science and Technology
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• 제14권7호
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• pp.764-772
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• 2000

In this paper, an engine-CVT integrated control algorithm is suggested by considering the inertia torque and the CVT ratio change response lag in acceleration. In order to compensate for drive torque time delay due to CVT response lag, two algorithms are presented: (1) an optimal engine torque compensation algorithm, and (2) an optimal engine speed compensation algorithm. Simulation results show that the optimal engine speed compensation algorithm gives better engine operation around the optimal operation point compared to the optimal torque compensation while showing nearly the same acceleration response. The performance of the proposed engine-CVT integrated control algorithms are compared with those of conventional CVT control, and It is found that optimal engine operation can be achieved by using integrated control during acceleration, and improved fuel economy can be expected while also satisfying the driver's demands.

• Journal of Biosystems Engineering
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• 제12권3호
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• pp.7-16
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• 1987

This study was carried out to develop a microcomputer-based data acquisition and control system which was able to collect the data of engine performance test automatically and control the speed and load of the engine. The results of the study are summarized as follows: 1. The signal processing devices, which were able to measure cylinder pressure, coolant temperature, compositions of exhaust gas, fuel consumption, engine rpm and torque etc., were developed. The results of calibration showed that all of devices had high accuracy ranging from 0.3% to 0.69% respectively. 2. The PIA (peripheral interface adapter) for interfacing digital signal and PTM (programmable timer module) for displaying real time every 0.0408 sec were designed and developed. 3. An engine-speed control system using a stepping motor and driver was developed. The control system had the stability, and faster settling time than the manual control system. 4. The automatic control system of electrical dynamometer, which was able to control the speed and load of dynamometer, was developed with a SSD (shackleton system driver) and D/A converter. 5. The computer programs, which were able to collect and process the data of engine tests, were developed using both the machine language and BASIC.

• 전자공학회논문지B
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• 제31B권6호
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• pp.53-62
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• 1994

In this paper, a fuzzy logic-based idle speed controller is designed for automotive engine with a purpose of high efficiency and low pollution. When the idle speed is low engine operation is not smooth, otherwise fuel consumption is incresed. Therefore the idle speed must be maintained as low as possible within the scope that ensures smooth operation of engine. By simulation, we show that the idle speed controller has generated a proper control signal as engine condition or enviornment varies, and also operated well for unexpected cases. Also, an engine simulator, which is used as a basic tool for controller design, is developed and utilized for reduction of development time and cost.

• Journal of Biosystems Engineering
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• 제17권4호
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• pp.396-403
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• 1992

In order to operate a combine harvester at the optimum conditions and maximum performance, a forward speed control system(FSCS) was designed and develped. The FSCS consisted of engine, continuously variable V-belt transmission, threshing unit, traveling unit, detecting unit, and controller. Each components of the system were mathematically modeled. By a computer simulation, the effects of control parameters such as hydraulic piston speed, speed ratio, dead band of engine speed on the system performance were analysed, and the optimum control conditions were identified. The system appeared to be the most stable at the hydraulic piston speed of 10.6mm/s and the speed ratio of 0.4. The proper dead band of engine speed appeared to be 30rpm through the simulation and verification tests.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 B
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• pp.696-698
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• 1997

The marine diesel engine have been widely applied with a mechanical hydraulic governor to control the ship speed for long time. But it was recently very difficult for the mechanical hydraulic governor to control the speed of engine under the condition of low speed and low load because of jiggling by rough fluctuation of rotating torque and hunting by dead time of diesel engine. In order to analyze the speed control system the transfer function was converted from z to w transformation. The author proposed velocity control system with feedback loop by PID controller in order to stabilize for unstable area. The influence of dead time was discussed by Nichols chart and unit step response curve. It was confirmed through computer simulation that the performance improvement of a mechanical hydraulic governor can be obtained by PID controller.

• 수산해양기술연구
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• 제33권1호
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• pp.46-58
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• 1997

The energy saving is one of the most important factors for profit in marine transportation. In order to reduce the fuel oil consumtion the ship's propulsion efficiency must be increased as possible. The propulsion efficiency depends upon a combination of an engine and a propeller. The propeller has better efficiency as lower rotational speed. This situation led the engine manufacturers to design the engine that has low speed, long stroke and a small number of cylinders. Consequently, the variation of rotational torque became larger than before because of the longer delay-time in fuel oil injection process and an increased output per cylinder. As 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 variation of the delay-time and the parameter perturbation. In this paper we consider the delay-time and the perturbation of engine parameters as the modeling uncetainties. Next we design the robust servo controller which has zero offset in steady state engine speed, based on H sub($\infty$) control theory. The validity of the controller was investigated through the response simulation. We used a personal computer and an analog computer as the digital controller and the engine (plant) part respectively. And, we could certify that the designed controller maintains its robust servo performance even though the engine parameters may vary.

• 수산해양기술연구
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• 제30권4호
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• pp.320-328
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• 1994

In 1980 s to 1990 s the marine propulsion diesel engines have been developed into lower speed and longer stroke for the enegy saving (small S.F.O.C). As these new trends the conventional mechanical-hydraulic governors were not adapted to the new requirements and the digital governors have been adopted in the marine use. The digital governors usually use the control algorithms such as the PID control, optimal control, adaptive control and etc. While the engine has delay time and parameter variations these control algorithms have difficulty in considering the stability and the robustness for the model uncertainty. In this study, the $H_{\infty}$ controller design method are applied in order to design the feedback controller K(s) to the speed control of the low speed marine diesel engine, and the two-degree-of-freedom control system is constituted with $H_{\infty}$controller. By comparison of responses of the two-degree-of-freedom control system under the delay time and parameter variations is confirmed.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2000년도 춘계학술대회 논문집(Proceeding of the KOSME 2000 Spring Annual Meeting)
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• pp.1-5
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• 2000

The conventional PID controller has been extensively used to speed control of marine diesel engines. However one of drawbacks is that its control performance can be degraded if the parameters are fixed on whole operating points. In this paper a scheme for integrating PID control and the fuzzy technique is presented to control speed of a marine diesel engine on whole operating points. At first the PID controller is designed at each speed mode whose parameters are optimally adjusted using a genetic algorithm, Then fuzzy "if-then" rules combine the controllers as a consequence part. To demonstrate the effectiveness of the proposed fuzzy controller a set of simulation works on a marine diesel engine are carried out.rried out.