Akira Iijima

• Nihon University

The objective of this study is to investigate in detail the basic combustion characteristics and abnormal combustion characteristics in the engine cylinder during drop-in of a synthetic fuel, dimethyl carbonate, at varying content rates to an existing fuel, Primary Reference Fuel (PRF). An optically accessible engine capable of flame propagation ve...

It is generally known that the temperature and mixture concentration in the combustion chamber influence knock intensity. It is assumed that the distribution of temperature and mixture concentration in the end-gas region of a two-stroke engine differs depending on the ignition position. Therefore, this study investigated the effect of the ignition...

In this study, three types of gasoline surrogate fuels were used to investigate the effect of fuel chemical composition on combustion and auto-ignition characteristics. For the study, an optically accessible engine capable of velocity analysis was used to observe the combustion and auto-ignition behavior. The results showed that the knock intensity...

div class="section abstract"> 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 fo...

div class="section abstract"> This study investigated the effect of the ignition positions in a two-point ignition system on homogeneous charge compression ignition (HCCI) combustion. Focus was put on controlling the ignition timing, and changes in combustion behavior due to the ignition positions were observed on the basis of in-cylinder combustio...

As a means for reducing combustion fluctuation, which is an issue for realizing lean combustion, researches using a method such as a high flow in a cylinder are actively conducted. However, there are still many unclear points on the influence of discharge specifications on combustion. So, in this research, we generated a flow field in the cylinder...

Homogeneous Charge Compression Ignition (HCCI) has attracted much attention as a combustion system for internal combustion engines because it is capable of achieving high efficiency and clean exhaust emissions. However, it is difficult to control the ignition timing of HCCI engines and their range of stable operation is limited to low loads. Approa...

div class="section abstract"> Engine knock is the one of the main issues to be addressed in developing high-efficiency spark-ignition (SI) engines. In order to improve the thermal efficiency of SI engines, it is necessary to develop effective means of suppressing knock. For that purpose, it is necessary to clarify the mechanism generating pressure...

div class="section abstract"> This study focused on a non-equilibrium plasma discharge as a means of assisting HCCI combustion.Experiments were conducted with a four-stroke single-cylinder engine fitted with a spark electrode in the top of the combustion chamber for continuously generating non-equilibrium plasma from the intake stroke to the exhaus...

div class="section abstract"> Internal combustion engines have been required to achieve even higher efficiency in recent years in order to address environmental concerns. However, knock induced by abnormal combustion in spark-ignition engines has impeded efforts to attain higher efficiency. Knock characteristics during abnormal combustion were inve...

div class="section abstract"> Lean-burn technology is regarded as one effective way to increase the efficiency of internal combustion engines. However, stable ignition is difficult to ensure with a lean mixture. It is expected that this issue can be resolved by improving ignition performance as a result of increasing the amount of energy discharged...

div class="section abstract"> Homogeneous Charge Compression Ignition (HCCI) combustion has attracted widespread interest because it achieves high efficiency and can reduce particulate matter (PM) and nitrogen oxide (NOx) emissions simultaneously. However, because HCCI engines lack a physical means of initiating ignition, it is difficult to control...

div class="section abstract"> 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...

Preliminary studies have been done in a framework of the “Symbolic Project of College of Science and Technology, Nihon University” on the new technologies potentially capable of improving energy conversion efficiency. New concepts for thermal engine, solar and nuclear energy utilization, and for their associated numerical simulation were proposed....

This study investigated the effect of ignition timing on knocking in an SI engine. Autoignition and abnormal combustion behavior were examined by using light absorption spectroscopy and in cylinder flame visualization techniques. The result showed that the knocking intensity under the same autoignition timing was declined by advancing ignition timi...

We focused on a homogeneous charge compression ignition（HCCI）engine. HCCI engine is high efficiency and clean combustion. But it has a problem that restraint of steep combustion in the high load and control of the combustion phasing are difficult. In this study, we studied characteristic of the combustion in supercharged HCCI engine with each two k...

Homogeneous Charge Compression Ignition (HCCI) combustion has attracted widespread interest in recent years as a clean, high-efficiency combustion system. However, it is difficult to control the ignition timing in HCCI engines because they lack a physical means of inducing ignition. Another issue of HCCI engines is their narrow operating range beca...

End-gas compression by propagating flame in super-lean SI engines was simulated by a RCM to uncover the spontaneous ignition process of the end-gas in in-cylinder under highly turbulent conditions. Lean n-heptane-air mixture of 0.5 and 0.7 in equivalence ratio was employed. In-cylinder turbulence was generated by a perforated plate set in the cylin...

An investigation was made of the fundamental combustion characteristics of a supercharged Homogenous Charge Compression Ignition (HCCI) engine operating on a gaseous fuel blend of dimethyl ether and methane. Besides measuring the in-cylinder pressure, spectroscopic techniques were used to measure light absorbance and light emission intensity. Exhau...

Supercharging is one way that be cited for expanding the high-load operating limit that is an issue of the homogeneous charge compression ignition (HCCI) engine. Spectroscopic measurements and chemical kinetic simulations were performed in this study to investigate in detail how varying the equivalence ratio by means of the intake air pressure infl...

In this study, the behavior of the autoignition in a supercharged SI engine was investigated by using light emission and absorption spectroscopic measurements. Spectroscopic measurements were applied to investigate the behavior of formaldehyde (HCHO) and OH radicals in the interval from the occurrence of a cool flame to autoignition. As a result, f...

div class="section abstract"> One issue of downsized and supercharged engines is low-speed pre-ignition (LSPI) that occurs in the low-speed and high-load operating region. One proposed cause of LSPI is the influence of the engine oil and its additives. However, the effect of engine oil additives on pre-ignition and the mechanism involved are still...

div class="section abstract"> Internal combustion engines today are required to achieve even higher efficiency and cleaner exhaust emissions. Currently, research interest is focused on premixed compression ignition (Homogeneous Charge Compression Ignition, HCCI) combustion. However, HCCI engines have no physical means of initiating ignition such as...

div class="section abstract"> It is difficult to control the ignition timing of Homogeneous Charge Compression Ignition (HCCI) engines because they lack a physical means of igniting the mixture. Another issue of HCCI engines is their narrow operating range owing to the occurrence of misfiring at low loads and abnormal combustion at high loads. As a...

div class="section abstract"> 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 recogni...

div class="section abstract"> The purpose of this study is to elucidate flame propagation behavior of homogeneous propane-air mixture under application of non-uniform electric field. A needle-shaped electrode was attached to the ceiling and a plate electrode was set at bottom of combustion chamber, so that the electric field was applied in the dire...

div class="section abstract"> Unresolved issues of Homogeneous Charge Compression Ignition (HCCI) combustion include an extremely rapid pressure rise on the high load side and resultant knocking. Studies conducted to date have examined ways of expanding the region of stable HCCI combustion on the high load side such as by applying supercharging or...

div class="section abstract"> Homogeneous Charge Compression Ignition (HCCI) engines have attracted much attention and are being widely researched as engines characterized by low emissions and high efficiency. However, one issue of HCCI engines is their limited operating range because of the occurrence of rapid combustion at high loads and misfirin...

The purpose of this study is to elucidate flame propagation behavior of homogeneous propane-air mixture under application of non-uniform electric fields. The non-uniform electric field was generated between the needle-shaped electrode and plate electrode, and a positive polarity single pulse high voltage was applied to the needle-shaped electrode (...

This study investigated the effect of streamer discharge on lean-combustion in an internal combustion engine. A continuous streamer discharge was generated in the wall-side of the combustion chamber of a 2-stroke optically accessible engine that allowed visualization of the entire bore area. The experimental results showed that the weak flame was i...

This study investigated the origin of knocking combustion accompanied by pressure wave and strong pressure oscillations in a Homogeneous Charge Compression Ignition (HCCI) engine. Experiments were conducted with a two-stroke single cylinder optically accessible engine that allowed the entire bore area to be visualized. The test fuel used was n-hept...

This study investigated the effect of streamer discharge on combustion in a Spark Ignition (SI) engine. A continuous streamer discharge was generated in the spark plug of the combustion chamber of a 2-stroke optically accessible engine that allowed visualization of the entire bore area. The experimental results showed that ignition and combustion o...

Supercharged direct-injection engines are known to have a tendency toward abnormal combustion such as spontaneous low-speed pre-ignition and strong knock because they operate under low-speed, high-load conditions conducive to the occurrence of irregular combustion. It has been hypothesized that one cause of such abnormal combustion is the intrusion...

Although metallic compounds are widely known to affect combustion in internal combustion engines, the potential of metallic additives in engine oils to initiate abnormal combustion has been unclear. In this study, we investigated the influence of combustion chamber deposits derived from engine oil additives on combustion in a spark-ignited engine....

Spontaneous low-speed pre-ignition, strong knock and other abnormal combustion events that occur in supercharged direct-injection engines are viewed as serious issues. The effects of the engine oil and the components of engine oil additives have been pointed out as one cause of such abnormal combustion. However, the mechanisms involved have yet to...

This study investigated the effect of streamer discharge on autoignition and combustion in a Homogeneous Charge Compression Ignition (HCCI) engine. A continuous streamer discharge was generated in the center of the combustion chamber of a 2-stroke optically accessible engine that allowed visualization of the entire bore area. The experimental resul...

Homogeneous Charge Compression Ignition (HCCI) engines are being widely researched today, having attracted considerable interest for their low emissions and high efficiency. However, HCCI engines have a narrow range of stable operation owing to the occurrence of extremely rapid combustion at high loads and misfiring at low loads. The results of pre...

A detailed analysis was made of a supercharged Homogeneous Charge Compression Ignition (HCCI) engine combustion using in cylinder spectroscopic measurements and fourier transform infrared (FTIR) spectroscopic analyses of the exhaust emissions. A mechanically driven supercharger was used to increase intake air pressure. A mass flow controller was us...

To clear the combustion characteristics of an HCCI engine, We performed a supercharged HCCI combustion experiment using two kinds of mixed fuel. In this study, we investigated the relationship between the exhaust components and thermal efficiency by using FT-IR exhaust gas analysis and spectroscopic measurement in the combustion chamber. The result...

In the present study, in-cylinder spectroscopic measurements and Fourier-transform infrared analysis of the exhaust gas were used to investigate combustion characteristics under a condition where supercharging was applied to moderate rapid combustion in a test HCCI engine until misfiring occurred. A chemical kinetic simulation was also performed to...

Knocking combustion experiments were conducted in this study using a test engine that allowed the entire bore area to be visualized. The purpose was to make clear the detailed characteristics of knocking combustion that occurs accompanied by cylinder pressure oscillations when a Homogeneous Charge Compression Ignition (HCCI) engine is operated at h...

This study investigated the characteristics of the HCCI combustion process in detail by means of in-cylinder visualization of the entire bore area and ultraviolet absorption spectroscopic measurement in the combustion chamber. Special attention was focused on the influence of the equivalence ratio and ignition timing on the degree of local dispersi...

A great deal of interest is focused on Homogeneous Charge Compression Ignition (HCCI) combustion today as a combustion system enabling internal combustion engines to attain higher efficiency and cleaner exhaust emissions. Because the air-fuel mixture is compression-ignited in an HCCI engine, control of the ignition timing is a key issue. Additional...

Combustion experiments were conducted with an optically accessible engine that allowed the entire bore area to be visualized for the purpose of making clear the characteristics that induce extremely rapid HCCI combustion and knocking accompanied by cylinder pressure oscillations. The HCCI combustion regime was investigated in detail by high-speed i...

The purpose of this study is to elucidate flame propagation behavior of three mixtures under application of non-uniform electric field. Three gaseous fuels were mixed with standard air and test fuels were hydrogen, methane and propane. The equivalence ratio of methan-air mixture was 1.05 and equivalence ratio of propain-air mixture was 0.9 becase t...

In previous study, the cellulosic liquefaction fuel (CLF) was made from woods by the direct liquefaction process and the wood tar was used as a solvent, however CLF was not ignited by the compression ignition and was not mixed with diesel fuel. In practical use of CLF, fatty acid methyl ester was used to mix with diesel fuel stably and completely....

There are strong demands today to further improve the thermal efficiency of internal combustion engines against a backdrop of various environmental issues, including rising carbon dioxide (CO_2) emissions and global warming. One factor that impedes efforts to improve the thermal efficiency of spark ignition engines is the occurrence of knocking. Th...

Against a background of rising CO_2 emissions, there is a need for further improvement in fuel economy of spark ignition (SI) engines. One hurdle to interfere improvement in fuel economy of SI engine is knocking. The knocking of SI engines is auto-ignition at unburned gas in the end of combustion chamber that caused various negative impacts to engi...

Homogeneous Charge Compression Ignition (HCCI) combustion has been the focus of widespread research interest in recent years as a combustion system that enables internal combustion engines to achieve higher efficiency and lower exhaust emissions. Because of the characteristics of this combustion regime, HCCI engines are inherently highly efficient...

A Homogeneous Charge Compression Ignition (HCCI) engine was operated under a continuous firing condition in this study to visualize combustion in order to obtain fundamental knowledge for suppressing the rapidity of combustion in HCCI engines. Experiments were conducted with a two-stroke engine fitted with a quartz observation window that allowed t...

There are few investigations to change wood biomasses to the industrially available energy, so that a new conversion technology of biomass to liquid fuel has been established by the direct liquefaction process. However, cellulosic liquefaction fuel (for short CLF) cold not mixed with diesel fuel. In this study, the plastic was mixed with wood to im...

Engine downsizing with a turbocharger / supercharger has attracted attention as a way of improving the fuel economy of automotive gasoline engines, but this approach can be frustrated by the occurrence of abnormal combustion. In this study, the factors causing abnormal combustion were investigated using a supercharged, downsized engine that was bui...

The purpose of this study is to clarify ignition characteristics and engine performance of FAME for 4-stroke diesel engine in low compression ratios. Diesel fuel and coconut oil methyl ester (CME) were selected as test fuels, because CME consisted of saturate FAMEs which were good ignition characteristics. To reduce the compression ratio, thin copp...

The growing severity of global environmental issues in recent years, including air pollution and the depletion of fossil fuels, has made it necessary for internal combustion engines to achieve higher efficiency and lower exhaust emission levels. Calls for reducing atmospheric emissions of carbon dioxide (CO2) necessitate thoroughgoing measures to l...

This study examined Homogeneous Charge Compression Ignition (HCCI) combustion characteristics in detail on the basis of in-cylinder combustion visualization, spectroscopic measurements of light emission and absorption and chemical kinetic simulations. Special attention was focused on investigating and comparing the effects of the fuel octane number...

Homogenous Charge Compression Ignition (HCCI) combustion experiments were conducted in this study using a single-cylinder test engine fitted with a sapphire observation window to facilitate visualization of the entire cylinder bore area. In addition to in-cylinder visualization of combustion, spectroscopic measurements were made of light emission a...

HCCI combustion has attracted considerable interest as a new combustion concept for internal combustion engines in recent years because of their potential for high efficiency and clean combustion. And thermal efficiency will be as good as higher compression ratio has been known. However, knowledge about compression ratio change of the HCCI engine i...

The cellulosic liquefaction fuel (CLF) was made from woods by the direct liquefaction process. Coconuts-oil Methyl Ester (CME) of 5 wt.% was used to mix CLF and diesel fuel, because CLF was not completely mixed with diesel fuel. To clarify a desirable CLF fraction for the diesel engine, CLF was divided into two fractions by the distillation: 200 to...

In plasma jet ignition, the hot jet gas was ejected after plasma jet finished to issuing and the hot gas jet also influenced the combustion enhancement effect. This study clarified the influence of igniter configuration on development of hot gas jet and plasma luminescence. When the cavity depth was deep and orifice diameter was small, the maximum...

Homogeneous Charge Compression Ignition (HCCI) combustion has attracted considerable interest as a new combustion concept for internal combustion engines because of their potential for high efficiency and can reduce nitrogen oxides (NOx) and particulate matter (PM) emissions simultaneously to provide low levels of exhaust pollutants. The HCCI combu...

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...

This study clarified the influence of hot gas jet on combustion enhancement effect for lean mixture in the plasma jet ignition. The hot gas jet was generated by the high temperature plasma and was ejected from igniter after plasma jet finished issuing. In combustion tests, propane-air mixture at equivalence ratio of 0.6 was used and the mixture was...

抄録 The HCCI engine has attracted for high efficiency and low exhaust emissions. However, the HCCI combustion process has two issues to be resolved : ignition timing control, slower combustion. In order to overcome these issues, it is necessary to investigate in detail the low-temperature oxidation reactions that distinctly characterize HCCI combust...

div class="section abstract"> An air motor with regenerating system for propulsion of a bicycle was newly developed. An air motor was driven by the compressed air and the bicycle was propelled. When the bicycle was decelerating, the air motor was acted as a compressor and the kinetic energy of bicycle was regenerated as compressed air. The purpose...

div class="section abstract"> The application of emulsified fuel for diesel engines is expected to reduce NOx and soot simultaneously. The purpose of this study is to clarify the influence of water content in emulsified fuel and fuel injection timing on diesel engine performance. The engine performance of emulsified fuel was compared with the water...

Homogeneous Charge Compression Ignition (HCCI) combustion has attracted widespread interest because it achieves high efficiency and can reduce particulate matter (PM) and nitrogen oxide (NOx) emissions simultaneously. However, combustion proceeds extremely rapidly in the HCCI process due to simultaneous ignition at multiple locations in the cylinde...

It was explored that the flame propagation behavior of hydrogen-air mixture under the application of positive and negative non-uniform electric field by using a constant volume vessel. For applying a non-uniform electric field, a needle-shaped electrode was attached to the center of the combustion chamber ceiling and a plate electrode was attached...

Homogeneous Charge Compression Ignition (HCCI) combustion has attracted considerable interest as a new combustion concept for internal combustion engines in recent years because of their potential for high efficiency and clean combustion. However the HCCI combustion process has two issues to be resolved: ignition timing control, slower combustion....

This study clarified the influence of high temperature gas jet on combustion enhancement effect for lean mixture in the plasma jet ignition by the use of combustion bomb. The hot gas jet was generated by the plasma and was ejected after the plasma jet finished injecting. The combustion chamber had a cylindrical shape with 80 mm of diameter and 40 m...

This study examined the effects of fuel composition and intake pressure on two-stage high temperature heat release characteristics of a Homogeneous Charge Compression Ignition (HCCI) engine. Light emission and absorption spectroscopic measurement techniques were used to investigate the combustion behavior in detail. Chemical kinetic simulations wer...

Homogeneous Charge Compression Ignition (HCCI) combustion offers the advantages of high efficiency and low emissions of pollutants. However, the characteristics of HCCI combustion can prevent suitable engine operation owing to the rapid combustion process that occurs accompanied by a steep pressure rise when the amount of fuel injected is increased...