This thesis shows the results of investigations about the combustion mechanisms of low-temperature premixed processes, in particular those in which only a partial homogenization of the fuel mixture is achieved, since they represent a realistic solution for commercial engine applications. Measurements has been carried out on a modern 6-cylinder diesel engine equipped with a rapid-prototyping ECU...

This study investigates the effects of intermediate temperature heat release (ITHR) on autoignition reactivity full boiling range gasolines with different octane sensitivity through intake and simulated exhaust gas recirculation (EGR) sweeps in a homogenous charge compression ignition (HCCI) engine. To isolate ITHR effects, low was suppressed use high oxygen mole fraction. For quantification IT...

Nowadays, increasingly stricter regulations on emission reduction are inducing rapid developments in combustion science. Low-temperature (LTC) is an advanced technology that increases engine’s thermal efficiency and even provides low emissions of nitrogen oxides (NOx) particulate matter (PM). The often uses early direct injections to achieve sufficient mixture homogeneity. This leads increasing...

Homogenous charge compression ignition (HCCI) combustion is spontaneous multi-site combustion of a nominally premixed air/fuel mixture that exhibits high rate of pressure rise and short combustion duration. To avoid excessive pressure rise rate and knocking, HCCI engines are fueled with highly diluted mixture using a combination of excess air and/or EGR. HCCI combustion is attractive due to ...

• All tested blends offer a HC and CO advantage over conventional diesel at low-load. emissions increase with increasing biofuel content medium-load high-EGR LTC. Crevice volume non-negligible for LTC operating points. An experimental study was performed on single-cylinder high-speed direct-injection research engine to determine the effects of biodiesel combustion characteristics during low tem...

operating an engine with homogeneous charge compression ignition (hcci) technique is a promising technique to lower nox and pm emissions of engines while achieving high efficiency and lower fuel consumption. nevertheless, applications for hcci are still limited due to the absence of a definite means to control ignition timing and narrow operating region. a single cylinder diesel engine with com...

During the last decade extensive research has been made at Lund University, Sweden, on a lean premix (prevaporize) combustion concept with burnt gas recirculation and a metallic flame holder. From this concept a new lean premixed natural gas combustion chamber with internal combustion gas recirculation (CGR) has been developed for the V160/SOLO 161 Stirling engines. This combustor has ultra-low...

Homogeneous charge compression ignition (HCCI) seems to be the most promising solution for gasoline engines in the light of future emissions regulations. This novel combustion technique allows for significant reduction of fuel consumption and engine-out NOX emissions at low and medium engine load/speed conditions. High heat release rate enables realization of the Otto cycle close to ideal, incr...

The amount of pollutant gases in the atmosphere has reached a critical state due to an increase in industrial development and the rapid growth of automobile industries that use fossil fuels. The combustion of fossil fuels produces harmful gases such as carbon dioxide, nitrogen monoxide (NO), soot, particulate matter (PM), etc. The use of Dimethyl Ether (DME) biofuel in diesel engines or other c...

at the present work, the effect of cold exhaust gas recirculation (egr) on combustion and pollution of a dual fuel engine has been investigated by cfd code fire. the turbulent flow within the combustion chamber is simulated using the k-ε turbulence model, which is modified for engine flows. “wave” and “eddy break up” models are employed to predict combustion and spray process. the calculations ...