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This paper provides the importance of helical coil sub-cooled condenser which has a compact structure, large heat transfer area, and high heat transfer capability in comparison to the straight sub-cooled condenser in the automobile vehicle. The HVAC unit has the largest parasitic load on the engine. Hence, by improving the coefficient of performance of the air-conditioning (A/C) system, the reduction in vehicule emissions is possible. Previous studies explain that there is generation of secondary flow inside the fluid in the circular cross-section of the helical coil. By using the effect of the secondary flow generation, authors tried to enhance the heat transfer rate as it leads to heterogeneous temperature distribution across the periphery of the tube and causes a higher heat transfer. For the purpose of the study, a prototype with a square cross-sectional 2.7 mm × 2.7 mm channel with flat fins towards the outer side has been constructed.

In order to clarify the diesel fuel spray characteristics inside the cylinder, we developed two novel techniques, which are preparation of same level of temperature and pressure ambient as inside cylinder and quantitative measurement of vapor concentration. The first one utilizes combustion-type constant-volume chamber (inner volume 110cc), which allows 5 MPa and 873K by igniting the pre-mixture (n-pentane and air) with two spark plugs. In the second technique, TMPD vapor concentration is measured by using Laser Induced Exciplex Fluorescence method (LIEF). The concentration is compensated by investigation of the influence of ambient pressure (from 3 to 5 MPa) and temperature (from 550 to 900 K) on TMPD fluorescence intensity. By using two techniques, we investigated the influence of nozzle hole diameter, injection pressure and ambient condition on spray characteristics.

The experiments were done in order to obtain the fundamental information that would be needed to build a physical model which expresses the heat transfer phenomena in the intake port model and manifold. In the experiments, the heating conditions and the period of the cyclic change of the gas velocity were changed as experimental parameters. In addition to those parameters, the Strouhal number was applied to express oscillating flow. As a result, the heat transfer in the experiments became clear, and the equations were obtained to show the Nusselt number using the Reynolds number, the Graetz number and the Strouhal number.

The purpose of this study is to find the suitable working conditions of a Pressure Wave Supercharger (PWS) that is coupled to a gasoline engine experimentally. The working condition is validated by stationary measurements on an engine dynamometer. To achieve an easier system structure, it was examined to use the engine output for driving of PWS. As a result, it was confirmed that the engine coupled with PWS could be driven by making the ratio of the PWS rotor speed and the engine speed constant.

Temperature distribution as the flame propagated and contacted to the wall of the combustion chamber was measured by real-time holographic interference method, which mainly consisted of an argon-ion laser and a high-speed video camera. The experiment was done with a constant volume chamber and propane-air mixture with several kinds of equivalence ratios. From the experimental results, it can be found that the temperature distribution outside the zone from the surface of the combustion chamber to 0.1mm distance could be measured by counting the number of the interference fringes, but couldn't within this zone because of lacking in the resolution of the used optical system. The experimental results show that the temperature distribution when the heat flux on the wall increases rapidly and when the heat flux shows the maximum value are quite different by the equivalence ratio.

The electronic controlled carburetor and ignition system has been developed. In accordance with various working conditions of the engine, the system adjusted corresponding control parameters; air fuel ratio and ignition timing, therefore it could keep the engine working on the optimal conditions. Through analyzing overall performance of the engine based on the experimental data, we had concluded that the specific fuel consumption was improved about 8-10%, and the exhaust emission performance was improved correspondingly after electronic control, the improved ratio was about 10% for HC emission and 97% for CO emission.

Temperature measurement experiments with intake port model were done to achieve the fundamental information on constructing physical model that expresses the heat transfer phenomena in the intake manifold and intake port. The experiments were done with steady airflow, and the size, shape, heating condition of the port model and mass flow rate were changed as experimental parameters. As the results, it was clear that the developing condition of velocity and thermal boundary layer had greater influence than the shape factor, and the coefficient and the exponent of the equation derived from the relationship between Nusselt number and Reynolds number had great difference from those of generally used Colburn's equation in undeveloped entrance region, but they got closer as developing boundary layer.

In this paper we propose a new multi-functional steering wheel switch for HVAC and audio systems. This new switch has five buttons on the front side of the spoke area and one button with vibration on the backside of it. Drivers can operate either HVAC or audio functions with the front switches, and HVAC or audio mode can be alternatively selected by pressing the back switch. Since different vibration modes are assigned for the HVAC and audio mode, drivers can also easily recognize which function can be operated. By changing the assignment of the mode in this way, the switch can operate more than 10 functions with 6 buttons allocated on the spoke area. Several kinds of evaluations were performed in order to develop this multi-functional switch. At first, to optimize the positions of the buttons, the behaviors of thumbs and fingers were measured. Also the physical workload of the thumb motion and middle fingers' postures was evaluated when subjects operated the switches.

This paper presents technical solutions and a development process to accomplish not only superior fuel economy but also excellent driveability with a turbocharged diesel engine for heavy duty trucks. For better fuel economy, one of the basic considerations is how to decrease the friction losses of the engine itself while keeping the required horsepower and torque characteristics. A high boost turbocharged small engine offers this possibility, but it has serious disadvantages such as inferior low speed torque, poorer accelerating response, insufficient engine braking performance, and finally not always so good fuel consumption in the engine operating range away from the matching point between engine and turbocharger. These are not acceptable in complicated traffic conditions like those in Japan - a mixture of mountainous and hilly roads, city road with numerous traffic signals, and freeways.

Described herein is the tuning of the combustion system of a direct injection type diesel engine to obtain low emission level and better fuel economy. Though the most important method of emission control for a direct injection system is considered to be timing retardation, it brings a higher level of smoke density and fuel consumption. In order to remove these faults, the authors developed a new combustion system based on a newly designed intake port which provides a favorable local mixing of fuel droplets and air in the combustion chamber for ignition by means of air turbulence. This new combustion system was analyzed with high speed photographs which were taken from the underside of the piston to enable observing the whole combustion chamber. Favorable characteristics of ignition and burning pattern of the new system were recognized by this analysis.

Described here is the tuning of the combustion systems of a precombustion chamber diesel engine for lower level of exhaust gas emission. The key points of the tuning are the decrease of the prechamber volume, the selection of the combustion chamber configuration, the injection nozzle characteristics and the optimum injection timing. It was made clear, in the results of investigation, that the degradation of lubricating oil and the cavitation pitting on the outer wall of cylinder liner were directly concerned with the combustion characteristics of low emission systems. And both problems have been solved. The result of combustion tuning of the engine shows less than 5 g/hp-h of NOx + HC with CARB 13 mode test cycle without deterioration of performance nor durability.

Radio noise generated by the ignition system of internal combustion engines is primarily caused by the capacitive discharge current flowing in the ignition circuit when the spark occurs at spark gap. It is known that suppression of the capacitive discharge current usually effective in reducing the radiated ignition noise level. [1]* However, with exposed engines such as outboard marine, motorcycles, and particularly, in devices with long metal bodies, the radiated level peaks at a frequency which is determined by the length of the metal body. The authors found that the phenomenon described above could be explained by assuming electrostatic induction current. This was based on the noise voltage from the ignition system to the device. This paper intends to report the findings of this research.

This investigation was concerned with the rate of heat transfer from the working gases to the combustion chamber walls of the internal combustion engines. The numerical formula for estimating the heat transfer to the combustion chamber wall was derived from the theoretical analysis and the experiment, which were used the constant volume combustion chamber and the actual gasoline engine. As a result, mean heat transfer in the internal combustion engine becomes possible to estimate with measuring the cylinder pressure. In addition, the derived numerical formula forms with quite simple variables. Therefore it is very useful for engine design.

Measuring precise cylinder pressure traces of internal combustion engines is an important factor for estimating their performances. It is known that the actual pressure readings measured with piezoelectric pressure transducers nave various forms of error. This paper is devoted to a study of compensation methods for reducing the errors caused by time constant values and thermal shock. Numerical analysis were carried out for the both errors to derive the equations of error compensation using the actual pressure data. The results indicate that the errors are corrected quite well with the obtained equations.

The relations of luminous intensity of the radicals, CH, C2, and OH radical, and the equivalence ratio, ϕ under high combustion pressure region (7.0MPa maximum) were investigated. Luminous intensity of each radical and combustion pressure were experimentally obtained using a constant volume combustion chamber. It was found that luminous intensity of each radical can be expressed as a function of ϕ and the combustion pressure. The estimation of ϕ was done within the region, 0.8<ϕ<1.2 and 2.0MPa

This paper discusses the compact structure, innovative and unique approach of high performance spiral coil sub-cooled condenser for compact power plant/engine applications. The motivation behind this study is to reduce the engine emission by improving the coefficient of performance for air-conditioning unit. Since the air conditioning system is the most power consumption units after the power plant, so it significantly affects the fuel consumption and the hazardous gas emissions. In the air condition cycle, the condenser unit is addressed as one of the important devices, and thus, the author tried to reduce the energy consumption by improving the performance of the condenser. The most advantage points of this study is to use spiral coil sub-cooled condenser, which elaborates the effect of secondary flow generation inside the fluid and is known as the Dean’s effect.

An empirical equation was developed for modeling the heat transfer phenomena taking place in an intake manifold which included the backflow gas effect. In literature, heat transfer phenomenon at intake system is modeled based on steady flow assumptions by Colburn analogy. Previously, authors developed an equation with the introduction of Graetz and Strouhal numbers, using a port model experimental setup. In this study, to further improve the empirical equation, real engine experiments were conducted where pressure ratio between the intake manifold and engine cylinder were added along with Reynolds number to characterize the backflow gas effect on intake air temperature. Compared to the experimental data, maximum and average errors of intake air temperature estimated from the new empirical equation were found to be 2.9% and 0.9%, respectively.

For improving the thermal efficiency and the reduction of hazardous gas emission from IC engines, it is crucial to model the heat transfer phenomenon starting from the intake system and predict the intake air’s mass and temperature as precise as possible. Previously, an empirical equation was constructed using an experimental setup of an intake port model of an ICE, in order to be implemented into an engine control unit and numerical simulation software for heat transfer calculations. The empirical equation was based on the conventional Colburn analogy with the addition of Graetz and Strouhal numbers. Introduced dimensionless numbers were used to characterize the entrance region, and intermittent flow effects, respectively.

In order to get better results in the Formula SAE of Japan, it is necessary to develop a small displacement engine with an ideal fuel consumption rate. Therefore, the authors started to improve an existing engine by combining with glow plug heated sub-chamber and lean burn. Lean burn conditions are usually adopted in gasoline engines, having the advantages of high specific heat ratio, low pump loss, and low cooling loss due to requiring a decreased combustion temperature. The combination of these elements can be expected to vastly improve thermal efficiency and fuel consumption. Unfortunately, however, when the mixture becomes lean, the ignition delay increases, and the flame propagation speed reduces. This leads to an increase in combustion fluctuation. The authors intend to solve this problem by installing a glow plug in a newly designed sub-chamber. This type of device would usually be used to heat the sub-chamber of a diesel engine to solve the cold start problem.

This paper oriented towards spiral coil sub-cooled condenser (SCSCC) which is used for the automotive air conditioning system. Therefore, the effect of curvature diameter has been carefully measured by CFD as it reduces/intensify the centrifugal force. This centrifugal force is responsible for Dean vortices and leads to the generation of secondary flow inside the refrigerant. By taking advantage of this secondary flow, the performance of the SCSCC can be improved. CFD analysis comprises curvature diameter from 13mm to 110mm, which varied the Dean number from 7577 to 2605. The author tried to evaluate the complicated phenomena that occurred within the SCSCC. However, the turbulent kinetic energy which is one of the critical factors of heat transfer coefficient illustrates 0.009m2/s2 and 0.006m2/s2 for large and small Dean number, respectively, toward the outer side of the channel.