Progress and recent trends in homogeneous charge compression ignition (HCCI) engines

There has been an enormous amount of research in recent years in the area of thermo-chemical conversion of biomass into bio-fuels (bio-oil, bio-char and bio-gas) through pyrolysis technology due to its several socio-economic advantages as well as the fact it is an efficient conversion method compared to other thermo-chemical conversion technologies. However, this technology is not yet fully developed with respect to its commercial applications. In this study, more than two hundred publications are reviewed, discussed and summarized, with the emphasis being placed on the current status of pyrolysis technology and its potential for commercial applications for bio-fuel production. Aspects of pyrolysis technology such as pyrolysis principles, biomass sources and characteristics, types of pyrolysis, pyrolysis reactor design, pyrolysis products and their characteristics and economics of bio-fuel production are presented. It is found from this study that conversion of biomass to bio-fuel has to overcome challenges such as understanding the trade-off between the size of the pyrolysis plant and feedstock, improvement of the reliability of pyrolysis reactors and processes to become viable for commercial applications. Further study is required to achieve a better understanding of the economics of biomass pyrolysis for bio-fuel production, as well as resolving issues related to the capabilities of this technology in practical application.

https://cyberleninka.org/article/n/1011788.pdf

Biofuels production through biomass pyrolysis - a technological review.

The potential of di-methyl ether (DME) as an alternative fuel for compression-ignition engines: A review

The hydrogen-fueled internal combustion engine : a technical review.

The development of four-stroke, spark-ignition engines that are designed to inject gasoline directly into the combustion chamber is an important worldwide initiative of the automotive industry. The thermodynamic potential of such engines for significantly enhanced fuel economy, transient response and cold-start hydrocarbon emission levels has led to a large number of research and development projects that have the goal of understanding, developing and optimizing gasoline direct-injection (GDI) combustion systems. The processes of fuel injection, spray atomization and vaporization, charge cooling, mixture preparation and the control of in-cylinder air motion are all being actively researched, and this work is reviewed in detail and analyzed. The new technologies such as high-pressure, common-rail, gasoline injection systems and swirl-atomizing gasoline fuel injectors are discussed in detail, as these technologies, along with computer control capabilities, have enabled the current new examination of an old objective; the direct-injection, stratified-charge (DISC), gasoline engine. The prior work on DISC engines that is relevant to current GDI engine development is also reviewed and discussed.

The fuel economy and emission data for actual engine configurations are of significant importance to engine researchers and developers. These data have been obtained and assembled for all of the available GDI literature, and are reviewed and discussed in detail. The types of GDI engines are arranged in four classifications of decreasing complexity, and the advantages and disadvantages of each class are noted and explained. Emphasis is placed upon consensus trends and conclusions that are evident when taken as a whole. Thus the GDI researcher is informed regarding the degree to which engine volumetric efficiency and compression ratio can be increased under optimized conditions, and as to the extent to which unburned hydrocarbon (UBHC), NOx and particulate emissions can be minimized for specific combustion strategies. The critical area of GDI fuel injector deposits and the associated effect on spray geometry and engine performance degradation are reviewed, and important system guidelines for minimizing deposition rates and deposit effects are presented. The capabilities and limitations of emission control techniques and aftertreatment hardware are reviewed in depth, and areas of consensus on attaining European, Japanese and North American emission standards are compiled and discussed.

All known research, prototype and production GDI engines worldwide are reviewed as to performance, emissions and fuel economy advantages, and for areas requiring further development. The engine schematics, control diagrams and specifications are compiled, and the emission control strategies are illustrated and discussed. The influence of lean-NOx catalysts on the development of late-injection, stratified-charge GDI engines is reviewed, and the relative merits of lean-burn, homogeneous, direct-injection engines as an option requiring less control complexity are analyzed. All current information in the literature is used as the basis for discussing the future development of automotive GDI engines.

Automotive Spark-Ignited Direct-Injection Gasoline Engines

https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/30292/1/IJHE32-14.pdf

Hydrogen as an ignition-controlling agent for HCCI combustion engine by suppressing the low-temperature oxidation

This study analyses factors influencing the thermal efficiency of a homogeneous charge spark ignition (SI) engine fuelled with hydrogen, focusing on the degree of constant volume and the cooling loss. The cooling loss from the burning gas to the cylinder walls in a homogeneous charge SI engine is quantitatively evaluated by analysing the cylinder pressure diagram and the exhaust gas composition. The degree of constant volume burning and the degree of constant volume cooling are also obtained by fitting the Wiebe function to the rate of heat release calculated using the cylinder pressure diagram. A comparison of combustion and cooling characteristics between hydrogen and methane combustion reveals that the cooling loss in hydrogen combustion is higher than that of methane combustion due to a thinner quenching distance and faster burning velocity for hydrogen combustion. It is also made clear that the higher cooling loss in hydrogen combustion results in lower thermal efficiency of hydrogen combusti...

https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/32512/5/JER2-1%28Heat2%29.pdf

Analysis of the degree of constant volume and cooling loss in a spark ignition engine fuelled with hydrogen

https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/30295/1/IJHE32-17.pdf

Improving thermal efficiency by reducing cooling losses in hydrogen combustion engines

Previous research by the authors showed that hydrogen combustion exhibits a higher cooling loss to the combustion chamber wall of an internal combustion engine compared to hydrocarbon combustion because of its higher burning velocity and shorter quenching distance. The high cooling loss means that reduction of the cooling loss is essential to establish a high thermal efficiency in hydrogen combustion engines. This research analyzed the applicability of equations to describe the heat transfer from burning gases to hydrogen combustion. The result shows that equations calculate a lower cooling loss than experimental values, and the use of correction coefficients does not accurately define the actual cooling rate. It is therefore concluded that the derivation of a new heat transfer equation for hydrogen combustion is necessary to improve the thermal efficiency of hydrogen fuelled engines.

https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/32325/1/JSAE%20Review%2023-3.pdf

Toshio Shudo

Papers

Hydrogen as an ignition-controlling agent for HCCI combustion engine by suppressing the low-temperature oxidation

Analysis of the degree of constant volume and cooling loss in a spark ignition engine fuelled with hydrogen

Improving thermal efficiency by reducing cooling losses in hydrogen combustion engines

Applicability of heat transfer equations to hydrogen combustion

HCCI Combustion of Hydrogen, Carbon Monoxide and Dimethyl Ether