• International Journal of Automotive Technology
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• v.4 no.3
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• pp.109-117
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• 2003

The analysis and evaluation of the transient performance by the transient response specifications under various acceleration speeds and types based on driver's typical acceleration habit are implemented by the experimental study to provide the appropriate direction for the transient control in a gasoline engine. The concept of the transient response specifications which consist of delay time, rising time, maximum overshoot and settling time, and the analysis method using them are introduced to evaluate the characteristics of the transient performance quantitatively. Furthermore four acceleration speeds and four acceleration types are set respectively to realize the various transient states which are similar to the real drive. Several performance parameters in terms of engine speed, manifold absolute pressure, fuel injection duration and air excess ratio are measured simultaneously during the various acceleration using a throttle actuator controlled by a PC. The transient response specifications characterized well the transient performance for the various acceleration speed and types quantitatively. Delay and rising time with increment of the acceleration speed became shorter, but settling time did longer. Intensified acceleration type appeared to be the most economical in view of fuel consumption, and linear acceleration type was found to have the least harmful emission concentration.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.3
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• pp.295-300
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• 2018

Conventionally, a PI control algorithm has been widely used as a speed control algorithm for BLDC motor. The PI control algorithm has a disadvantage in that is slow to reach the steady state due to the slow speed and torque response with various speed changes. Therefore, in this paper, PWM fuzzy logic control algorithm which can reach the steady state quickly by improving the response speed although there is a little overshoot is proposed. PWM reduces response speed and fuzzy logic control algorithm minimizes overshoot. The proposed PWM fuzzy logic control algorithm consists of DC chopper, PWM duty cycle regulator, and fuzzy logic controller. The performance and validity of the proposed algorithm is verified by simulation with Simulink of Matlab 2018a.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.7
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• pp.951-962
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• 2010

An experimental study was performed to investigate the improvement of response performance of a turbocharged diesel engine under the operating conditions of low speed and fast acceleration. In this study, the experiment for improving the low speed and acceleration performance is performed by means of injecting air into the intake manifold of compressor exit during the period of low speed and application of a fast acceleration from low speed. The effects of air injection into the intake manifold on the response performance were investigated at various applicant parameters such as air injection pressure, accelerating rate, accelerating time, engine speed and load. The experimental results show that air injection into the intake manifold at compressor exit is closely related to the improvement of turbocharger lag under low speed and accelerating conditions of a turbocharged diesel engine. During the rapid acceleration period, the air injection into the intake manifold of turbocharged diesel engine indicates the improvement of the combustion characteristics and gas pressure in the cylinder. At low speed range of the engine, the effect of air injection shows the improvement of the pressure distribution of turbocharger and combustion pressure during the period of gas exchange pressure.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1027-1028
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• 2006

In this paper, design of current and speed controller for DC motor drive system using Embedded Target for TI C2000DSP in Matlab/Simulink is introduced. Current and speed controller is designed and implemented using program simply and easily, and speed control response of DC motor can be advanced. Current and speed control of DC motor is carried in eZdsp F2812 control board using Embeded Target for TI C2000DSP in Matlab/Simulink. Speed feedback is processed through A/D converter using tacho generator as speed sensor, and current feedback is processed through A/D converter using hall sensor as current sensor. Controller is designed to PI current controller and PI speed controller. Current and speed response is verified through simulations and experiments.

• 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.

• Journal of Fisheries and Marine Sciences Education
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• v.12 no.2
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• pp.199-212
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• 2000

It is very important to investigate the hull response of a fishing vessel in the sea to ensure the safe navigation and fishing operation in rough sea by preserving excellent sea keeping qualities. For this purpose, the author measured various responses of three stem trawlers in waves using real sea experimental measuring system. The author analyzed the experimental data using the statistical and spectral analyzing method to get the characteristics of the motion responses of the vessels according to the wave height and the ship's speed. The results obtained can be summarized as follows ; (1) Rather higher response of the pitch motion due to the wave height appeared in the head sea and the bow sea than any other wave direction without relevance to ship's size. In case of the roll motion, the beam sea and the quartering sea have a high response value. The period of peak of the pitch motion and the roll motion according to the wave height in each vessel has almost same value respectively. (2) The change of response of the pitch motions deeply depend on the ship's speed in the head sea and the bow sea, but not in the other wave direction. (3) The change of response of the roll motions in the beam sea, the quartering sea and the following sea are affected by the influence of the ship's speed in 5k't to 8k't, but not related to the ship's speed in out of that range.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.7
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• pp.138-147
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• 1995

The conventional PWM method, which was used in controlling the on-off valve, such as high-speed solenoid valve, was modulating the width of the pulse applied to the valve, by selecting arbitrary sampling time and modulating the duty-ratio in proportion to the error. However, in this method, a selection of long sampling time was inevitable and it was unable to get a high accuracy and a quick response. This study is for designing an appropriate controller for high-speed solenoid valve by proposing an improved duty-ratio modulation method using the Saw-toothed Carrier Wave which enables a short sampling time selection, high accuracy of control, and a quick response. Test which was carried out in the laboratory shows that transient and steady state response could be improved by PID controller.

• The KSFM Journal of Fluid Machinery
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• v.16 no.6
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• pp.5-11
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• 2013

Torque control methods of wind turbine are mainly classified into two methods: torque-mode and speed-mode methods. The traditional torque-mode method, in which generator torque proportional to square of generator speed is determined, has been chosen in many wind turbines but its response is slower as they are larger in multi-MW size. Torque control methods based on both speed-mode and torque-mode can be used to make response of wind turbine faster. In this paper, two torque control methods based on the traditional torque-mode method are applied to a 2.75 MW wind turbine. It is shown through some simulation results for real turbulence wind speeds that torque control method based on torque-mode has the merit of reducing fluctuations of generated power than PI controller based on speed-mode.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.6
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• pp.946-951
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• 2009

An induction motor based on DTC(Direct Torque Control) is being increasingly used in various industrial applications. DTC offers faster torque response and better speed control with lesser hardware and processing costs in compared with other controlled drives. This study was to evaluate performance of DTC for induction motor of electric propulsion ship. The simulation results indicated good speed and torque response from the low to middle speed range. Also, DTC has advantages such as the independency on motor parameter.

• Smart Structures and Systems
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• v.20 no.2
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• pp.197-205
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• 2017

The dynamic performance of railway bridges under high-speed trains draws the attention of bridge engineers. The vibration issue for long-span bridges under high-speed trains is still not well understood due to lack of validations through structural health monitoring (SHM) data. This paper investigates the correlation between bridge acceleration and train speed based on structural dynamics theory and SHM system from three foci. Firstly, the calculated formula of acceleration response under a series of moving load is deduced for the situation that train length is near the length of the bridge span, the correlation between train speed and acceleration amplitude is analyzed. Secondly, the correlation scatterplots of the speed-acceleration is presented and discussed based on the transverse and vertical acceleration response data of Dashengguan Yangtze River Bridge SHM system. Thirdly, the warning indexes of the bridge performance for correlation scatterplots of speed-acceleration are established. The main conclusions are: (1) The resonance between trains and the bridge is unlikely to happen for long-span bridge, but a multimodal correlation curve between train speed and acceleration amplitude exists after the resonance speed; (2) Based on SHM data, multimodal correlation scatterplots of speed-acceleration exist and they have similar trends with the calculated formula; (3) An envelope line of polylines can be used as early warning indicators of the changes of bridge performance due to the changes of slope of envelope line and peak speed of amplitude. This work also gives several suggestions which lay a foundation for the better design, maintenance and long-term monitoring of a long-span high-speed bridge.