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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 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.

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.

This paper represents the adaptation of turbo charger to single cylinder 450cc SI engine which is used for the student formula competition. The experiment and 1D engine simulation called as GT-Power were performed to confirm the effect of valve profile, compression ratio and air fuel ratio on the engine performance under the naturally aspirated condition. The maximum valve lift of the intake valves increased 27% and that of the exhaust valves increased 15% as compared with the low profile cam. The compression ratio was increased from 12.3 to 13.5 by changing the piston top land length in order to improve the thermal efficiency. It was confirmed that the torque peak was moved from 6000 rpm to 8000 rpm by changing the valve profile. Furthermore, turbo charger was adapted to the engine as changing the capacity of the turbocharger, the maximum boost pressure and the air fuel ratio.

For further development of the thermal efficiency of SI engines, the robust control of the air-fuel ratio (A/F) fluctuation is one of the most important technologies, because the A/F is maintained at the theoretical constant value, which causes the increase of the catalytic conversion efficiency and the reduction of pollutant emission. We developed the robust controller of the A/F, which is the method to change the fuel injection rate by using the feed-forward (FF) controller considering the heat transfer at the intake system. The FF controller was verified under transient driving conditions for a single cylinder, and the A/F fluctuations were reduced at approximately 84%.

In this study, we have evaluated the performance of undertray and rear wing in formula SAE. The undertray was adopted to increase the driving force transmission. And in order to further increase the driving force and prevent the car from oversteering in high speed areas, a rear wing was mounted. Finally, by mounting these aerodynamic devices, driving force increased by 41% (undertray 14%, rear wing 27%) at the speed of 90km/h, and by calculating the value of stability factor measured by cornering power, improvement of the vehicle's oversteering tendency was confirmed.

High rigidity and lightweight are important factors in every frame of vehicles. In Formula SAE vehicle design, to achieve this purpose the target value of the torsional rigidity of the frame was determined in the test run, and the conditions of analysis were also developed to be able to measure the compartment of the frame which concerns the actual driving conditions of the vehicle. Additionally focusing on the dynamic conditions of the vehicle, special devices for the frame were employed. Finally, the weight of 2008 year's model was saved by up to 29% from 2005 year's model, in spite of the torsional rigidity was downsized by only 12%.

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.

This research focuses on the improvement of torque at the middle engine speed of a motorcycle engine with resonance supercharging. The resonance supercharging intake system is realized with a simple modification to the intake collector geometry. A one-dimensional computational model is employed to simulate the pressure wave propagation and to optimize the configuration of it. The experiments confirmed the increase in the engine torque for the entire operation range and the maximum gain of 33% was achieved at 8500rpm. The resonance effect is further investigated through three-dimensional simulation, in which the intake airflow rate, static pressure distribution are analyzed.

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.

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.

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.

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

When the power or specific fuel consumption is estimated in design process, thermodynamic consideration for the estimation is generally insufficient. Hence, a theory that can estimate these performances accurately is investigated in this paper. As a result of investigation, it is clear that the effect of pumping loss in wide-opene throttle valve operation has to be excluded from the mechanical loss which is measured in the motoring test. It also becomes clear that a new coefficient called pumping loss coefficient ηP has to be considered for the negative work for pumping. From the foregoing, theoretical formulas for estimating the net power Pe and net specific fuel consumption be. which are formed with various efficiencies and coefficients are as follows: It is verified that the estimation from these formulas agree well with the experimental test values using stoichiometric mixture ratio.