This paper is on developing the advanced method in diagnosis electronic control of gasoline and LPG engine. The experimental methods using oscilloscope were employed to measure waveform of hot wire, hot film, oxygen, ignition coil and injector. Through these analysis, emission reduction and fuel economy improvement were expected by depict vehicles. The experiment was carried out during no-load condition. A summary of the important results are as follows. 1. The factors affecting the secondary ignition waveform from the primary ignition waveform were reverse surge voltage and induced voltage . Actually shape of primary ignition waveform was normal, but a secondary ignition waveform was measured badly. 2. The area of the voltage-time diagram of secondary ignition waveform means the value of the effective discharge of energy. This value is negative, the fuel economy could be predicted badly and is positive, good value of fuel economy could be predicted. 3. Inspection and maintenance of DLI ignition vehicles compared to DIS ignition vehicles were essential. The secondary ignition waveform of the C type vehicle were worst compare to those of the different type vehicles. The injection duration of injector was largest C, D types in the order named, was shortest E, F type. As a result, E, F type are most effective among Gasoline vehicles.
Active front steering(AFS) system is able not only to vary steering ratio between steering wheel and tire wheel but also to steer front tires independently. In this paper, steering gear ratios and an active steering algorithm are proposed for the AFS system. Steering gear ratio is a function of vehicle speed and steering angle. Active steering is generated when the error of yaw-rate is larger than some threshold. To verify the performance of yaw stability, hardware-in-the-loop simulation system is made up of column type active steering system, driving display, steering effort reaction system and controller
This paper describes study of the converter topologies for a low-cost, high-efficiency switched reluctance motor(hereafter abbreviated as SRM) drive. The considered converter employs two-switch split AC supply configuration. The converter preserves a single switch per phase as well as a single phase-leg rectifier circuit realizing the fewest component count to achieve a highly cost effective solution for two-phase SRM drive. Comparative study between the considered converter and other converters are provided. Analysis of the modes of operation and mathematical modeling are also provided. Analysis and simulation results are provided to validate the converter. The considered split AC converter can be a strong candidate for low-cost applications such as power tools, fans, and small appliances where both cost and efficiency are most valued.
New material which absorbs impact energy effectively and has excellent mechanical property is developed. The used amount is increased at automobile field day by day. Aluminum foam with various air sell lattices within is one of representative porosity metals which are used at many automobile parts because it has the excellent lightness and impact energy absorption function. For this reason, aluminum foam is used widely as a component among composite materials. This study aims to investigate systematically the mechanical property of foam through computer simulation. In order to obtain the property of aluminum foam, aluminum foam is designed as the dimension of 100mm × 100mm × 25mm and the striker that has the diameter of 12.5mm is supposed to impact aluminum foam with impact energies of 6J, 10J, and 14J. Aluminum foam is not penetrated when striker given by energy of 6J or 10J impacts into it, but aluminum foam is penetrated by striker in case of impact energy of 14J. The result can provide the basic data in order to develop the advanced composite material.
In this paper, cycle performance analysis of two-stage compression and two-stage expansion refrigeration system using Natural refrigerants is presented to offer the basic design data for the operating parameters of the system. Alternative natural refrigerant R290(Propane), R600(Butane), R717(Ammonia), R1270(Propylene) for freon refrigerant R22 were used working fluids in this study. The operating parameters considered in this study included evaporation temperature, condensation temperature, subcooling degree, superheating degree, and mass flow rate ratio of inter-cooler. The main results were summarized as follows : The COP of two-stage compression and two-stage expansion refrigeration system increases with the increasing subcooling degree and mass flow rate ration of inter-cooler, but decreases with the increasing evaporating temperature, condensing temperature and superheating degree. Therefore, subcooling degree, mass flow rate ratio of inter-cooler of two-stage compression and two-stage expansion refrigeration system using alternative nreon refrigerants have an effect on COP of this system.
This paper aims to develop a crutched walking frame with one-wheel driving system for the walking-impaired person as the aged. The walking frame is made up of four main parts : the steering and suspension system, the driving unit using the worm gear, the sensor and the controller. The walking frame can be controlled to keep the stable attitude by using the tilt sensor that measure the tilting of frame. The experimental results without control motion and with control motion for the downhill and uphill are presented in this study. Finally, a comparison between these results is presented to show the validity of system.
As fires have frequently occurred with large scale at cultural assets and warehouses, the development of Korean type demolition fire apparatus for efficient fire fighting becomes important. In this study, structural stability is investigated for assembly model of boom and outrigger by using computational structural analysis. Analysis results of boom and outrigger unit are also compared with assembly model. As this study result, equivalent stress result of boom unit is about 6% higher than assembly model and equivalent stress result of outrigger unit is about 15% higher than assembly model.
This paper describes the design and implementation of the split AC converter topology for a low-cost, high-efficiency switched reluctance motor (hereafter abbreviated as SRM drive. The considered converter employs a low-cost, single-switch-per-phase configuration. as well as a single phase-leg rectifier circuit realizing the fewest component count to achieve highly cost effective solution for two-phase SRM drive. The design of the prototype converter as well as comparative study with the conventioal asymmetric converter is discussed. The converter is validated by both simulation and experimental results.
Aluminum foam has many superb properties such as light weight, impact absorption and thermal resistance by comparing with original metallic materials. Composite materials made of aluminum foam have used at various fields as automotive bumper, shock absorption, vessel and aircraft. But it is inefficient to join aluminum foam with bolt and nut because of the property of light weight. In this study, this approach is investigated by joining aluminum foam with adhesive. Impact fatigue and failure toughness at the commissure of adhesive structure are studied by simulation analysis. This study aims to investigate the shear strength evaluation at shear mode of adhesively bonded joint with double cantilever beam(DCB) made of aluminum foam.
The SMC(Sheet molding compound) process is widely used in the automotive industry to produce parts that are large, thin, lightweight, strong and stiff. Compression molded parts are formed by squeezing a glass fiber reinforced UP(Unsaturated Polyester) sheet, known as sheet mold compound(SMC), between two heated cavity surfaces. This paper has performed flow analysis to predict optimization process of low density SMC. After five types of design variables and six types of response variables were defined, DOE(Design of Experiment) and RSM (Response Surface Method) were applied in order to measure sensitivity of design variables and realize optimization through regression model. After design optimization, the total warpage of the SMC is reduced by about 12% compared to the initial design of SMC and cure time, cure temperature, clamping force and flow pressure are decreased by 0.6∼27% in comparison with the initial design. By doing this, the production costs could be diminished.
In this study, the performance characteristics of EGR Cooler applying to the current commercial vehicle was analyzed by the numerical analysis. Through the experiment the performance evaluation of EGR Cooler must need a lot of time and expenses. On the other hand, the numerical analysis has been used in many research areas as a way to reduce the cost and time. The analysis model of this study has a spiral shape tube. The exhaust gas passes through the inside of the tube. The performance of Cooler was analyzed according to the variation of gas mass flow rate. The results of analysis and experimental was confirmed that was indicating the same trend.
The smoke emission of biodiesel fuel was reduced remarkably in comparison with diesel fuel, that is, it was reduced approximately 36% at 2000rpm, full load condition. And, power, torque and brake specific energy consumption showed no significant differences. However, NOx emission of biodiesel fuel was increased compared with commercial diesel fuel. Also, the effects of exhaust gas recirculation(EGR) to reduce the NOx emission has been investigated. It was found that simultaneous reduction of smoke and NOx was achieved with biodiesel fuel(20vol-%) and cooled EGR method(10∼15%).
LEDs are increasingly used for many applications including automotive, display and special lighting applications. The performance and lighting characteristics of the LED depend on cooling condition because the power LED generates lots of heat. In this study, the effect of the generated heat from power LED module on cooling characteristics and performance is measured and evaluated. For experiments, the transient temperature of a power LED module with cooling condition is measured.
This study describes the amendment of Durbin's k-∈-v2-f model and its application to turbulent channel flow to test the model’s performance. Modeling redistribution and dissipation rate terms for the scalar v2 transport equation is considered by the elliptic blending equation which is used in the second moment closure generally. The prediction results are directly compared to the DNS and Durbin's original k-∈-v2-f model to assess the performance of the new model predictions and to show their reasonable agreement with the DNS and Durbin's model for all the flow characteristics that are analyzed for the present study.
Electric power steering system(EPS) is a new power steering technology for vehicle and important device for improving vehicle’s dynamics and static performances. EPS can be divided into the following three forms: the Column assist type EPS(C-EPS), the Pinion assist type EPS(P-EPS), and the Rack assist type EPS(R -EPS). System stiffness of Different types of EPS which effects on steering performance, are known by simulation result and measuring products. P types of EPS are more stiffer than C types of EPS and contribute to steering performance at on centre range of vehicles. By analyzing of performance with types of EPS, this paper proposed improving method for C-EPS stiffness.
The present study has measured the velocity distribution in a three-dimensional shape model of the rectangular settling tank using PIV system. The experiment system consists of hi-speed camera, laser and host computer. Reynolds number based on the guide wall height(H=25mm) has been applied during the whole experiments. The results showed that recirculation flow in settling tank exists and a internal flow weakly influenced by Reynolds number at Re=5×103 greater.
Dispersion conditions of exhaust gas emitted from the ship stack are varied due to the state of sea surface, ship velocity and external environment condition etc. In the certain circumstances, the exhaust gas flowing backward phenomena is appeared due to the shape of vessel structure. The negative pressure layers can appear at the rear part of deck house and cause the exhaust gas flowing backward phenomena. In this study, 1:100 scale model ship was manufactured and tested in the large wind tunnel test center to ensure the exhaust gas flow patterns. Measurement results showed that the greatest pressure point was x/H=1.55 at zone 6 and Case 2 was a relatively high wind pressure distribution.
There is a considerable amount of research on ship worker’s hearing loss caused by vibration and noise that comes from the ship’s construction. A further investigation that characterizes the sound that comes from building or repairing a ship is nonexistent or insufficient, however. To do this, a noise management plan is needed. It should include a generated sound process from the main sources of disturbance in the ship- building areas. And a soundproof measurement will identify the amount of noise reduction needed for a hearing- safe working environment. Finally, researchers in this study measured tests on the noise and the vibration process, and the noise caused by operations allowed for an investigation on the suitability of certain environmental conditions. Noise-related programs can be used to predict the noise distribution of the noise level characteristic. This can help identify and reduce the presence of sound interference through sound proofing measures.
The present study investigated the blood flow at microvascular network. The role of the blood viscosity and the yield stress of blood on the flow at the microvascular network was examined to find the condition of hemostasis. When the yield stress was less than 0.005Pa, there was no stagnant region in the capillary network used in the study. However, when the yield stress increased to 0.05Pa, stagnant areas began to appear, which grew and expanded rapidly with further increase in the yield stress. From the blood viscosity profile of a patient, one can estimate the yield stress of blood, from which the risk of hemostasis can be determined.
Because of the inherent flexibility in their design for improved material properties, composites have wide applications in aerospace vehicles and automobiles. The purpose of this study is to investigate the energy absorption characteristics of CFRP(Carbon Fiber Reinforced Plastics)tubes on static and impact tests. Static compression tests have been carried out using the static testing machine(Shin-gang buckling testing machine)and impact compression tests have been carried out using the vertical crushing testing machine. When such tubes were subjected to crushing loads, the response is complex and depends on the interaction between the different mechanisms that control the crushing process. The collapse characteristics and energy absorption were examined. Trigger and interlaminar number affect the energy absorption capability of CFRP tubes.