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Issues that must be addressed to make Homogeneous Charge Compression Ignition (HCCI) engines a practical reality include the difficulty of controlling the ignition timing and suppression of rapid combustion under high load conditions. Overcoming these issues to make HCCI engines viable for practical application is indispensable to the further advancement of internal combustion engines. Previous studies have reported that the operating region of HCCI combustion can be expanded by using DME and Methane blended fuels.(1), (2), (3), (4), (5) The reason is that the reaction characteristics of these two low-carbon fuels, which have different ignition properties, have the effect of inducing heat release in two stages during main combustion, thus avoiding excessively rapid combustion. However, further moderation of rapid combustion in high-load region is needed to expand the operation region. This study focused on supercharging and use of blended fuels.

In recent years, it has been expected the conversion of wasted biomass to industry available energy. In this study, 80 wt.% of wood and 20 wt.% of polypropylene were liquefied by the mineral oil used as solvent. The liquefied material was distilled, and distillation fraction of temperature from 493 to 573 K was recognized as light oil fraction CLF (Cellulose Liquefaction Fuel) and that from 378 to 493 K was recognized as naphtha fraction CLF. CLFs were blended with light oil and, in engine performance test, mixing ratio of light oil fraction CLF was 5 wt.%, and in vehicle running test, weight mixing ratios were 5 or 10 wt.%. In engine performance test, indicator diagrams and rate of heat releases of light oil fraction CLF 5 wt.% mixed light oil were almost equivalent to those of light oil in all load conditions, and engine performance and exhaust gas emissions were also almost equivalent to light oil.

In this study, a detailed analysis was made of supercharged HCCI combustion using a two-component fuel blend of dimethyl ether (DME), which has attracted interest as a potential alternative fuel, and methane. The quantity of fuel injected and boost pressure were varied to investigate the equivalence ratio and operating region conducive to optimal HCCI combustion. The results revealed that varying the boost pressure according to the engine load and applying a suitable equivalence ratio induced two-stage main combustion over a wide load range, making it possible to avoid excessively rapid combustion.

This study focused on the use of a two-component fuel blend and supercharging as possible means of overcoming these issues of HCCI combustion. Low-carbon gaseous fuels with clean emissions were used as the test fuels. The specific fuels used were dimethyl ether (DME, cetane number of 55 or higher) that autoignites easily And exhibits pronounced low-temperature oxidation reactions, methane (cetane number of 0) that does not autoignite readily and is the main component of natural gas which is regarded as petroleum substitute, and propane (cetane number of 5) that is a principal component of liquefied petroleum gas. The results of previous investigations have shown that the use of a blended fuel of DME and methane produces a two-stage main combustion process under certain operating conditions, with the result that combustion is moderated.

This study investigated the effects of recirculated exhaust gas (EGR) and its principal components of N2, CO2 and H2O on moderating Homogeneous Charge Compression Ignition (HCCI) combustion. Experiments were conducted using two types of gaseous fuel blends of DME/propane and DME/methane as the test fuels. The addition rates of EGR, N2, CO2 and H2O were varied and the effects of each condition on HCCI combustion of propane and methane were investigated. The results revealed that the addition of CO2 and H2O had the effect of substantially delaying and moderating rapid combustion. The addition of N2 showed only a slight delaying and moderating effect. The addition of EGR had the effect of optimally delaying the combustion timing, while either maintaining or increasing the indicated mean effective pressure and indicated thermal efficiency ηi.

The educational systems for driving vehicle are recently progressing every year like aircraft simulator. To know the learning process of training are very important for designing total education system. Therefore this research considers the methodologies of measuring human learning process when the beginner rider practicing by using motorcycle simulator. Here, a motorcycle needs the proper manipulating practice in the event of first riding because the manipulation use both hands and feet with keeping balance. For this reason in this paper it is considered the methodologies of measuring rider learning effectiveness by recording rider behavior and motorcycle movement.

Hydrogen has attracted attention as one of the key fuels for making internal combustion engines carbon neutral. However, the combustion characteristics of hydrogen differ greatly from those of conventionally used hydrocarbons. Therefore, in order to develop next-generation internal combustion engines that operate on hydrogen, it is first necessary to have a thorough understanding of the combustion characteristics of hydrogen. Engines that can take maximum advantage of those characteristics should be developed on the basis of that knowledge. Toward that end, the purpose of this study was to investigate the fundamental combustion characteristics of hydrogen in a test engine. This paper presents the results of an investigation of the effects on low-temperature oxidation reactions and autoignition when hydrogen was blended into dimethyl ether (DME) [1, 2], a gaseous hydrocarbon fuel.

This paper deals with the steering system with conventional round steering-wheel from the view point of Steer-by-Wire system design. Steering gear ratio and control force characteristics are selected as interface variables of the steering system. The concept of ideal steering gear ratio which is derived on the basis of mapping of steering wheel angle and vehicle path angle is proposed to determine steering gear ratio. Simulator experiments are conducted to investigate the effects of interface variables on system and driver’s control performance. Validity of proposed ideal steering gear ratio would be confirmed. Candidates for objective task performance measure to define desirable control force characteristics would be determined from the test results.

Technologies for further improving vehicle fuel economy have attracted widespread attention in recent years. However, one problem with some approaches is the occurrence of abnormal combustion such as low-speed pre-ignition (LSPI) that occurs under low-speed, high-load operating conditions. One proposed cause of LSPI is that oil droplets diluted by the fuel enter the combustion chamber and become a source of ignition. Another proposed cause is that deposits peel off and become a source of ignition. A four-stroke air-cooled single-cylinder engine was used in this study to investigate the influence of Ca-based additives having different properties on abnormal combustion by means of in-cylinder visualization and absorption spectroscopic measurements. The results obtained for neutral and basic Ca-based additives revealed that the former had an effect on advancing the time of autoignition.

A Spark Ignition Engine has some kinds of problem to be solved over many years, one of them is abnormal combustion; Low-speed pre-ignition (LSPI) under low-speed, high-load driving conditions for vehicle, and pre-ignition under longterm operation without cleaning a combustion chamber for gas cogeneration. As a cause for abnormal combustion, engine oil droplets diluted by liquid fuel and peeled combustion deposits delivered from engine oil are proposed. In this study, experiments were conducted focusing on engine oil additives having different chemical structure and abnormal combustion behavior. A four-stroke side-valve single cylinder engine that allowed in-cylinder visualization of the combustion flame was used in the experiments. The experimental results showed that the influence of DTC additive on abnormal combustion is small and the zinc component contained in the DTP additives had the effect of advancing the autoignition timing.

In this study, a spectroscopic method was used to measure the combustion characteristics of a test diesel engine when operated on dimethyl ether (DME) under a homogenous charge compression ignition (HCCI) combustion process. A numerical analysis was made of the elementary reactions using Chemkin 4.0 to perform the calculations. The results of the analysis showed that compression ratio changes and the methane additive influenced the autoignition timing in the DME-HCCI combustion process. In the experiments, reducing the compression ratio delayed the time of the peak cylinder pressure until after top dead center, thereby increasing the crankshaft output and thermal efficiency. The addition of methane enabled the DME-HCCI engine to provide crankshaft output equivalent to that seen for diesel engine operation at a low equivalence ratio. This paper discusses these effects in reference to the experimental and calculated results.

We developed a novel ignition method called laser breakdown-assisted long-distance discharge ignition (LBALDI) that combines laser breakdown with a discharge to realize lean combustion. The creation of laser breakdown plasma between electrodes for discharge enables discharges over longer distances than those of conventional sparkplug as inferred from laser-triggered lightning or laser-triggered gas switches. This method should help realize volumetric ignition through the creation of a long-distance discharge. Experiments on the fundamental discharge and ignition of methane/air mixtures were conducted. The optimum incident time of the laser prior to the application of a high voltage was found to reduce the sparkover voltage and markedly reduce the voltage required by LBALDI under pressurized air conditions. In the ignition experiment, LBALDI showed the fastest heat release rate at the lean flammable limit.

This paper describes a fundamental design for a riding simulator of two wheeled vehicle which is used to analyze the human factor of riders. At the first step of this research, the relationship between the movement of rider and behavior of a two wheeled vehicle is inquired with experiments on a proving ground. Based on the results, the degrees of freedom which is required by simulator and main input of rider are settled. This study goes along examination of the expression method of simulated movements, and production of the riding simulator.

This study investigated the influence of EGR and spark advance on knocking under high compression ratio, ultra-lean mixture and supercharged condition using premium gasoline as a test fuel. A high-compression ratio, supercharged single cylinder engine was used in this experiment. As a result, the period from ignition to autoignition was prolonged. In addition, knock intensity was drastically reduced. In other words, it is inferred that by combining an appropriate amount of EGR and spark advance, high efficiency operation avoiding knocking can be realized.

Although methane number is widely used to predict knocking occurrence and its intensity, it does not determine a fuel composition uniquely, that means, the knocking intensity by the different composition fuel must show difference even if the same methane number fuels are employed. To establish a novel index, the knocking intensity and the autoignitive propagation velocity, as consequence of spontaneous ignition process, are investigated both experimentally and numerically by using the different composition gaseous fuels with same methane number. Methane/ethane/air and methane/n-butane/air mixtures with the same methane number of 70 and the equivalence ratio of 0.5 were employed. They are rapidly compressed and ignited spontaneously by a Rapid Compression Machine. Ignition delay times, autoignitive propagation velocities, and knocking intensity were measured by acquired pressure histories and high-speed imaging.

In motorcycles, the mass difference between a vehicle and a rider is small and motions of a rider impose a great influence on the vehicle behaviors as a consequence. Therefore, dynamic properties of motorcycles should be evaluated not merely dealing with a vehicle but considering with a man-machine system. In the studies of a simulation for vehicle dynamics, various types of rider models have been proposed and it has already been reported that rider motions have a significant influence on the dynamic properties. However, the mechanism of the interaction between a rider and a vehicle has not been clarified yet. In our study, we focused on weave motion and constructed a full vehicle simulation model that can reflect the influences of the movements of the rider’s upper body and lower body. To construct the rider model, we first measured the vibrational characteristics of a human body using a vibration test bench.