Fuel design and management for the control of advanced compression-ignition combustion modes

Overview of hydrogen production technologies from biogas and the applications in fuel cells

Evolution, challenges and path forward for low temperature combustion engines

An experimental study of the biogas-diesel HCCI mode of engine operation

Biogas is a relatively mature renewable energy technology but still most commercial biogas power plants require significant financial incentives. Additionally, local shortages of very cheap digestible feedstocks limit biogas productivity, especially for larger biogas power plants (>1 MWe). Innovations that could improve cost-effectiveness and resource efficiency of biogas energy technology are therefore required. Over the last few years a number of potential process innovations for biogas technology have been proposed and investigated. However, the majority of these novel concepts has minimal or no impact on technology development. Disruptive innovations are very rare, but only they really matter for the economy. Therefore review reports that systematically compare, analyze and evaluate the suitability of these emerging methods with emphasis on technological excellence and realistic commercial potential are needed. This study presents potential process innovations from most recent patent and academic literature proposed for biogas (i) production, (ii) conditioning, (iii) utilization and (iv) industrial symbiosis. Within these four highly interdisciplinary categories the review attempts to provide short practical comments on selected methods and briefly analyzes their perspectives and constraints. Further, relevant biogas process innovation criteria are designed and multiple-criteria assessment of pre-selected potential process innovations is made. The paper concludes with the characterization of innovativeness of selected solutions and suggests future research needs for biogas energy technology that could bring new innovations in near term.

A review of potential innovations for production, conditioning and utilization of biogas with multiple criteria assessment

Effects of charge temperature and exhaust gas re-circulation on combustion and emission characteristics of an acetylene fuelled HCCI engine

In this work, biogas was used in a compression ignition (CI) engine in the homogeneous charge compression ignition (HCCI) mode as well as in the dual-fuel mode together with diesel. In the HCCI mode, the charge temperature and amount of diesel injected into the intake manifold were used to control combustion. The presence of carbon dioxide in biogas suppresses the high heat release rates normally encountered in neat-diesel-fuelled HCCI engines. Efficiencies close to diesel operation together with extremely low levels of nitric oxide (NO) and smoke were attained in a brake mean effective pressure (BMEP) range from 2.5bar to 4bar in the biogas—diesel homogeneous charge compression ignition (BDHCCI) mode. Proper control over the charge temperature was essential. Thermal efficiency was higher and NO, hydrocarbon, carbon monoxide, and smoke levels were lower than in the biogas—diesel dual-fuel mode. Thus, the BDHCCI mode is a viable option for using biogas in CI engines in the medium-load ranges. Opera...

Homogeneous charge compression ignition versus dual fuelling for utilizing biogas in compression ignition engines

HCCI Engine Operation with Acetylene the Fuel

It is becoming increasingly difficult for engines using conventional fuels and combustion techniques to meet stringent emission norms. The homogeneous charge compression ignition (HCCI) concept is being evaluated on account of its potential to control both smoke and NOx emissions. However, HCCI engines face problems of combustion control. In this work, a single cylinder water-cooled diesel engine was operated in the HCCI mode. Diesel was injected during the suction stroke (0° to 20° degrees aTDC) using a special injection system in order to prepare a nearly homogeneous charge. The engine was able to develop a BMEP (brake mean effective pressure) in the range of 2.15 to 4.32 bar. Extremely low levels of NOx emissions were observed. Though the engine operation was steady, poor brake thermal efficiency (30% lower) and high HC, CO and smoke were problems. The heat release showed two distinct portions: cool flame followed by the main heat release. The low heat release rates were found to result in poor brake thermal efficiency at light loads. At high brake power outputs, improper combustion phasing was the problem. Fuel deposited on the walls was responsible for increased HC and smoke emissions. On the whole, proper combustion phasing and a need for a wellmatched injection system were identified as the important needs.

S. Swami Nathan

Papers

An experimental study of the biogas-diesel HCCI mode of engine operation

Effects of charge temperature and exhaust gas re-circulation on combustion and emission characteristics of an acetylene fuelled HCCI engine

Homogeneous charge compression ignition versus dual fuelling for utilizing biogas in compression ignition engines

HCCI Engine Operation with Acetylene the Fuel

Effect of mixture preparation in a diesel hcci engine using early in-cylinder injection during the suction stroke