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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.

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.

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.

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.

Nowadays, cornering performance of FSAE (Formula SAE) cars are dramatically improved due to less mass, kinematic developments and tires. In such circumstance, under high speed conditions, aerodynamical devices work better. It had been decided to attach aerodynamical devices that consist of front wing, rear wing, diffuser (floor) and deflector for SR11 (Fig. 1, Table 1), a FSAE car developed by Sophia Racing (Japan). Fig. 1 SR11 Table 1Vehicle configuration of SR11 To start with developing aerodynamical devices, it had been assumed that how they work. Lap time simulation had been done with VI-car-realtime, which shows the laptime could be shorten by 2 seconds of 60 seconds for a usual FSAE endurance course with 60kgf at 60km/h downforce. Dragforce had been assumed to work well while once, it had been supposed to have a bad influence for laptime.

1 Many environmental problems, such as global warming, drain of fuel and so on, are apprehended in all over the world today, and down-sizing is one of the wise ways to deal with these problems. It is significant that a decrease of the engine power must not be produced by using a small displacement engine, so more efficient engine system should be designed to increase the torque with a little fuel. This study achieves an improvement of efficiency for mounting the super charging system on the small displacement engine. As a result, comparing a super charged engine and a naturally aspirated one to drive the same course and laps, fuel consumptions are 2547 [cc] and 3880 [cc], respectively, and an improvement of fuel consumption is 52%. Designing points to mount super charging system is introduced below. 1 It can be forecasted that intake air blow-by gas at the combustion chamber is increased in low engine speed because engine for motor cycle is used.

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.

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.

A historical review of Japanese turbocharged diesel engines for heavy duty vehicles is described, and newly developed turbocharged diesel engines of HINO are introduced. The design features of these engines include new turbocharging technologies such as highly backward curved impeller for compressor blade, variable controlled inertia charging and waste gate. Laboratory and field test results demonstrated better fuel economy and improved low speed and transient torque characteristics than the predecessors. Several operational experiences, technical analysis and reliability problems are discussed.

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.

In motorcycle market, there is demand for technology that makes it possible to drive fast safely. One such technology has already been commercialized; control that prevents front lift while enabling maximum acceleration performance. We have developed a more accurate version of this control. In order to maximize acceleration performance, it is necessary to keep front lift angle as close to zero as possible. Reducing output driving force helps to keep the front lift angle low, but if output driving force is reduced too much, it will degrade acceleration performance. Feedback control that reduces output driving force when front lift is detected is effective for optimizing this trade off, but increasing feedback gain too much to reduce front lift angle will cause output driving force to change suddenly, making for a less comfortable ride.

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.

Diesel engines need to optimize the fuel injection timing and quantity of each cycle in the transient operation to increase the thermal efficiency and reduce the exhaust gas emissions through the precise combustion control. The heat transfer from the working gas in the combustion chamber to the chamber wall is a crucial factor to predict the gas temperature in the combustion chamber to optimize the timing and quantity of fuel injection. Therefore, the authors developed both the heat loss and the polytropic index prediction models with the low calculation load and high accuracy. In addition, for the calculation of the heat loss and the polytropic index, the wall heat transfer model was also developed, which was derived from the continuity equation and the energy equation. The present study used a single cylinder diesel engine under the condition of engine speed of 1200 and 1500 rpm, and measured the local wall temperature and the local heat flux of the combustion chamber.

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.

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%.

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.

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.

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.

The paper reviews the experimental development of fuel economy of engine powering the 2012 Formula SAE single seat race car of the University of Sophia. The balance of high power and low fuel consumption is biggest challenge of racing engine. It was found that improving the efficiency of engine by supercharging as a way to achieve that. In order to adapt the supercharger for the engine, the important design points are below: It was found that intake air blow-by gas at combustion chamber is increased in low engine speed. To improve that, the valve overlap angle was changed to adopt supercharged engine and improve effective compression ratio. Typically the racing engine demands maximum torque for performance but that does not imply that the air fuel ratio should be rich than theoretical. The point is the maximum torque of the engine is proportional to the amount of air intake. Therefore, supercharged engine is possible to increase the supercharging pressure for bigger torque.

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.