Showing 3 results for Nox
M. Iranmanesh,
Volume 3, Issue 2 (6-2013)
Abstract
In this study, various percentage of DEE was added to the optimum selected ethanol-diesel blend (D-E10)
and optimized its blending ratio to overcome the poor ignition quality of ethanol when utilized in a single
cylinder DI diesel engine. Some physicochemical properties of test fuels such as heating value, viscosity,
and density and distillation profile were determined in accordance to the ASTM standards. The heating
value of the blends was reduced with addition of DEE. Front-end volatility of the blends was improved by
addition of DEE, which in turn improves the cold starting property. The uncertainty associated with
measurements was also measured. The data were analyzed statistically for 95% confidence level. The
results have shown that addition of biofuels, ethanol and diethyl ether, have improved the combustion and
emissions characteristics of the engine. Addition of ethanol and DEE improved smoke and NOx emissions
simultaneously. It was found the 8% DEE add to the D-E10 blend is the optimum combination based on the
performance and emission analysis with the exception of smoke opacity in which 15% DEE addition made
the lowest smoke opacity. At this optimum ratio the minimum peak heat release rate, the lowest NOx
emissions and the maximum BTE were occurred at full load condition. Meanwhile the lowest level of CO
and HC emissions were obtained at all the load conditions with the same blending ratio.
Mr Mushtaq Ahmad Rather, Mohammad Marouf Wani,
Volume 8, Issue 4 (12-2018)
Abstract
In this paper, a computational in-cylinder analysis of HCCI diesel engine was carried out using IC Engine FORTE (ANSYS 18.2) software package. The analysis used pre-defined industry standard CHEMKIN format for specifying a chemical reaction mechanism during the combustion duration. The investigation was carried out for the effects of various EGR mass percentages on the thermal and emission characteristics of a diesel engine running on HCCI mode of combustion. It was observed that an increase in EGR concentration resulted in the decrease in peak in-cylinder pressure and temperature and it was also found that when the EGR rates were increased beyond 75% there was no combustion happening within the cylinder. A considerable decrease in the NOx emissions was found with an increase in EGR mass percentage with almost negligible values when the EGR rates were increased beyond 50%, however there was a slight increase in un-burnt hydrocarbons.
Dr Ali Keshavarz, Fereshteh Khodamrezaee, Dr Sadegh Seddighi, Sepide Sarmast,
Volume 10, Issue 4 (12-2020)
Abstract
This work investigates the effects of hydrogen addition to compressed natural gas (CNG) on combustion characteristics and emission reduction using a closed cycle simulation with exact geometry of piston and cylinder head. The effect of equivalence ratio on combustion characteristic were investigated using a spark ignition (SI) engine fueled with CNG and addition of 10% vol, 15% vol and 20%vol hydrogen. Two different speed of 1500 and 3000 rpm have considered at full load condition. The modeling includes ECFM combustion model combined with K-ζ-f turbulent modeland has been done by AVL Fire software. Different volume fraction of Hydrogen with different excess air modeled and validated with experimental data. The validation procedure included in-cylinder pressure profile, maximum pressure, angle of maximum pressure, indicated mean effective pressure, and carbon monoxide (CO) emission showing a good agreement with the experimental results. The value of the peak pressure increases by hydrogen addition and it takes place sooner as the hydrogen volume fraction increases. However, the mean effective pressure drops 3.5%, 7% and 15% for HCNG 10, HCNG15 and HCNG20, respectively. CO emission decreases by increasing the hydrogen volume fraction. The results also indicate that hydrogen addition in lean combustion causes more CO reduction compared to the fuel-rich mixtures.
