A Study on Homogeneous Combustion in Porous Medium Internal Combustion Engine: A Review 2017-01-0788
Rapid depletion in fuel resources owing to the low efficiency of current automobiles has been a major threat to future generations for fuel availability as well as environmental health. Advanced new generation of internal combustion (IC) engines are expected to have far better emissions levels both gaseous (NOx and CO) and particulate matter, at the same time having far lower fuel consumption on a wide range of operating condition. These criteria could be improved having a homogeneous combustion process in an engine. Homogeneous mixing of fuel and air in HCCI leads to cleaner combustion and lower emissions. Since peak temperatures are significantly lower than in typical SI engines, NOx levels and soot are reduced to some extent. Because of absence of complete homogeneous combustion but quasi homogeneous combustion present in HCCI, there is still a possibility of further reducing the emissions as well as enhancing the engine performance. Post recent advancements, a new combustion concept has been proposed that fulfills all requirements to perform complete homogeneous combustion in I.C. engines using the Porous Medium Combustion Engine, called “PM -engine”. This is an I.C. engine with the following processes realized in a porous medium: internal heat recuperation, fuel injection and vaporization, mixing with air, homogenization, and 3Dthermal self-ignition followed by a homogeneous combustion. The P.M. combustion technology in I.C. engines can be realized in two ways :(i)Engine with periodic contact between PM and working gas in cylinder (closed chamber);(ii)Engine with permanent contact between PM and working gas in cylinder (open chamber). PM combustion Technology is characterized by very fast mixing of fuel with air occurring in 3Dstructure of PM-engine resulting in charge homogenization. Consequently, self-ignition process with simultaneous volumetric combustion occur in PM volume close to the TDC hence, ensuring uniform temperature field. This paper aims at reviewing the porous medium technology and provide a guide for technological enhancements in homogeneous combustion phenomenon in I.C. engines.