• International Journal of Automotive Technology
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• v.8 no.1
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• pp.49-57
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• 2007

This paper proposes a traction control system (TCS) that uses a sliding mode wheel slip controller and a PID throttle valve controller. In addition, a yaw motion controller (YMC) is also developed to improve lateral stability using a PID rear wheel steering angle controller. The dynamics of a vehicle and characteristics of the controllers are validated using a proposed full-car model. A driver model is also designed to steer the vehicle during maneuvers on a split ${\mu}$ road and double lane change maneuver. The simulation results show that the proposed full-car model is sufficient to predict vehicle responses accurately. The developed TCS provides improved acceleration performances on uniform slippery roads and split ${\mu}$ roads. When the vehicle is cornering and accelerating with the brake or engine TCS, understeer occurs. An integrated TCS eliminates these problems. The YMC with the integrated TCS improved the lateral stability and controllability of the vehicle.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.6
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• pp.880-885
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• 2009

The ships have a lot of electric machinery needed to supply electricity from the moment of launching coming out of dry dock to docking at jetty. Thus, the ships always have to use alternator and electric machinery that has low efficiency under the low load. Many government service ships like the MMU training ship have been spending lots of time at jetty rather than sailing at sea. These ships are operated under the condition of low load due to the operation of basic machinery at jetty and electric machineries are driven with the status of low efficiency. This paper would suggest the energy saving method for these ships. The investigation describes that shore connection is a great asset to these ships and that the flow rate control by adjusting revolution with the adoption of inverter is better than flow rate control by using throttle valve to save energy. The result is based on the investigation of cooling pump at MMU training ship.

• 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.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.5
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• pp.321-328
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• 2017

In this study, vortex tube system model is developed to predict the temperature of the hot and the cold sides. The vortex tube model is developed based on the system identification method, and the model utilized in this work to design the vortex tube is ARX type (Auto-Regressive with eXtra inputs). The derived polynomial model is validated against experimental data to verify the overall model accuracy. It is also shown that the derived model passes the stability test. It is confirmed that the derived model closely mimics the physical behavior of the vortex tube from both the static and dynamic numerical experiments by changing the angles of the low-temperature side throttle valve, clearly showing temperature separation. These results imply that the system identification based modeling can be a promising approach for the prediction of complex physical systems, including the vortex tube.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.695-701
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• 2009

Vortex tube is the device that can separate small particles from the compressed gas, as well as compressed gas into hot and cold flow. In this study, computational approach has been performed to analyze the characteristics of the vortex tube. Energy separation characteristics of the vortex tube has been tested for various geometric design parameters. For the given conditions, it is found that as the tube is lengthened, hot end temperature is reduced but cold end temperature does not influenced much. As the orifice diameter decreases, cold end temperature decreases. Also, as hot gas fraction increases, hot end temperature decreases. The results from this study can be used for the basic design parameter of the $CO_2$ reduction device.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.55-60
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• 2010

Vortex tube is the device that can separate small particles from the compressed gas, as well as compressed gas into hot and cold flow. Due to energy separation ability, a vortex tube can substitute for an EGR cooler of the automotive engine. In this study, experimental approach has been performed to analyze the energy separation characteristics of the vortex tube. Energy separation characteristics of the vortex tube has been tested for supply pressure, cold-out pressure, and hot-out pressure. As increasing supply pressure, energy separation effect increased. Maximum temperature exists about 0.85 of the cold-out-flow-ratio, and minimum exists about 0.35. Hot-out temperature of the vortex tube is affected by the hot-out and cold-out pressure. However, for the given conditions, cold-out temperature is independent of exit pressure change. The results from this study can be used for the basic design parameter of the EGR cooler substitute of an automotive engine.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1229-1235
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• 2014

At the LPG vehicle air intake system, most of dust particles in the air cleaner are removed. However very small particles are not removed and accumulated. The accumulation of carbon in air intake system is going to affect the idle speed control and sensor signal. It also causes engine chattering and transmission troubles of automatic transmission. This is study about cleaning up intake system using cleaning chemical. We can clean up the intake system by spraying cleaning liquid onto intake device when the engine is idling after intake hose is removed from warmed up vehicle. We can obtain the following experimental results by cleaning up ISC, surge tank, intake manifold, intake valves and combustion chamber. According to this results, the stroll valve works correctly and power rate of engine is up to the standard, it is smoothy to control the idling speed when a vehicle pulls up. After cleaning up CO grow down about 0.15%, HC does about 20~100 ppm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1429-1434
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• 2014

Recently, SUA(Sudden Unintended Acceleration) are increasingly occurred. However, all the responsibilities of SUA are accepted by an innocent driver despite of painful results due to mystery of accurate cause. If a driver raises this kind of trouble to the corresponding manufacturer, the automaker collects EDR installed in that vehicle and provides the result of their analysis as it turns out most of the analysis results were diagnosed "there is nothing wrong with the car". In this trend, the technology to protect drivers' position from SUA should be developed. In this study, the researchers aimed to develop a black box system that collects additional data from throttle valve which is considered as one of major causes of SUA accidents, in order to explain cause of SUA and defend innocent drivers.

• Journal of the Korean Institute of Gas
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• v.20 no.4
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• pp.1-6
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• 2016

A fuel supply system of heavy-duty CNG engine is composed as a module structure which is integrated by about 6 injectors. There are only one input and output passage for gas fuel supply in this injector module. The response performance for transient operation of an CNG engine is very poor because only one output fuel supply line is connected to the intake pipe after a throttle valve. In this study, a new guideline and internal flow design for the CNG injector module is suggested for the improvement of response performance by fluid dynamic simulations. As a result, the response performance of gas fuel supply can be improved by decreasing the total volume of internal flow passages and a same distance design from each injector to the exit of module shows good response performance and acquirement of linearity of fuel supply. But the injection order has little influence to injection performances.

• Journal of Drive and Control
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• v.13 no.2
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• pp.10-18
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• 2016

A front-end loader (FEL) mounted on an agricultural tractor is one of the most commonly used implements to mechanize routine agricultural tasks. When the FEL is used with a loaded bucket, careful operation is required to maintain safety and avoid spillage when the tractor passes a bump because a change in the gravity center of the tractor due to varied loadings can affect the stability of the tractor. Use of a boom suspension system consisting of accumulators and orifice dampers can be instrumental in reducing pitching vibrations while increasing the handling performance of the FEL-mounted tractor. The objective of this research was to reduce bump shocks by adding an orifice and a flow control valve to the original hydraulic circuit composed solely of accumulators. A simulation study was performed using the SimulationX program to investigate the effects of an accumulator and an orifice-throttle damper on bump shocks. Results showed that the peak pressure on a boom cylinder and the vertical acceleration of a bucket were significantly affected by use of both an accumulator and an orifice damper. In a field test conducted with a 75-kW tractor, the peak pressure of the boom cylinder, and the root mean square (RMS) vertical acceleration of the bucket and seat were reduced by on average, 23.0, 42.2, and 44.9% respectively, as compared to those measured with the original accumulator system, showing that an improved design for the accumulator hydraulic circuit can reduce bump shocks. Further studies are needed to design a tractor suspension system that includes the effects of cabin suspension and tires as well as dynamic analysis.