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

Models of soot formation and oxidation

https://www.colonius.caltech.edu/pdfs/ColoniusLele2004.pdf

Computational aeroacoustics: progress on nonlinear problems of sound generation

Combustion of hydrocarbon fuels within porous inert media

Hydrogen is known as a technically viable and benign energy vector for applications ranging from the small-scale power supply in off-grid modes to large-scale chemical energy exports. However, with hydrogen being naturally unavailable in its pure form, traditionally reliant industries such as oil refining and fertilisers have sourced it through emission-intensive gasification and reforming of fossil fuels. Although the deployment of hydrogen as an alternative energy vector has long been discussed, it has not been realised because of the lack of low-cost hydrogen generation and conversion technologies. The recent tipping point in the cost of some renewable energy technologies such as wind and photovoltaics (PV) has mobilised continuing sustained interest in renewable hydrogen through water splitting. This paper presents a critical review of the current state of the arts of hydrogen supply chain as a forwarding energy vector, comprising its resources, generation and storage technologies, demand market, and economics.

Hydrogen as an energy vector

Heat recirculation and heat transfer in porous burners

Numerical study of the effects of material properties on flame stabilization in a porous burner

Numerical and experimental study of the conversion of methane to hydrogen in a porous media reactor

In this paper, we report the results of an experimental investigation of methane-air combustion within a porous medium burner for various equivalence ratios and flow rates. Measurements of emissions and radiant output are presented. The results indicate that CO and NOx, emissions increase with flame speed. For a given equivalence ratio, however, NOx, emissions are fairly constant over the range of flame speed studied. The radiant output increases but the radiant thermal efficiency decreases with flame speed.

Janet L. Ellzey

Papers

Combustion of hydrocarbon fuels within porous inert media

Heat recirculation and heat transfer in porous burners

Numerical study of the effects of material properties on flame stabilization in a porous burner

Numerical and experimental study of the conversion of methane to hydrogen in a porous media reactor

Measurements of Emissions and Radiation for Methane Combustion within a Porous Medium Burner