On the Use of Thermodynamic Modeling for Predicting Cycle-to-Cycle Variations in a SI Engine under Lean Conditions

Engine Knock in an SI Engine with Hydrogen Supplementation under Stoichiometric and Lean Conditions

SAE International Journal of Engines ◽

10.4271/2014-01-1220 ◽

2014 ◽

Vol 7 (2) ◽

pp. 595-605 ◽

Cited By ~ 10

Author(s):

Yu Chen ◽

Robert Raine

Keyword(s):

Si Engine ◽

Engine Knock ◽

Lean Conditions

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Fuel Composition Effects on Emissions From a Spark-Ignited Engine Operated on Simulated Biogases

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.1338951 ◽

1999 ◽

Vol 123 (1) ◽

pp. 132-138 ◽

Cited By ~ 14

Author(s):

K. C. Midkiff ◽

S. R. Bell ◽

S. Rathnam ◽

S. Bhargava

Keyword(s):

Natural Gas ◽

Specific Energy Consumption ◽

Fuel Composition ◽

Nox Emissions ◽

Si Engine ◽

Composition Effects ◽

Brake Power ◽

Spark Timing ◽

Unburned Hydrocarbons ◽

Lean Conditions

Measurements are reported for a spark-ignited (SI) engine burning natural gas and three simulated biogas fuels (natural gas, CO2, and N2 mixtures). Exhaust concentrations of CO, CO2,O2,NOx, and unburned hydrocarbons, as well as brake power and brake specific energy consumption, were measured. Leaner mixtures, retarded spark timing and diluent addition CO2,N2 yielded reduced NOx emissions. NOx reductions up to 50 percent were achieved at MBT timing through diluent addition. Reduced peak temperatures caused by diluent addition, lean conditions, and retarded spark timing reduced combustion quality slightly, as evidenced by small increases in CO and unburned hydrocarbons emissions.

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NOx Emissions Reduction of a Natural Gas SI Engine Under Lean Conditions: Comparison of the EGR and RGR Concepts

ASME 2006 Internal Combustion Engine Division Spring Technical Conference (ICES2006) ◽

10.1115/ices2006-1310 ◽

2006 ◽

Cited By ~ 1

Author(s):

Olivier Le Corre ◽

Fre´de´ric Pirotais

Keyword(s):

Experimental Data ◽

Natural Gas ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Emissions Reduction ◽

Nox Emissions ◽

Si Engine ◽

Gas Recirculation ◽

Lean Conditions

In natural gas SI engines under lean conditions, NOx emissions reduction can be realized by injecting an additional mass flow rate to inlet gases. It can be easily done in situ using two techniques: EGR (Exhaust Gas Recirculation) or RGR (Reformed Gas Recirculation) which is an improvement of the usual EGR configuration. Exhaust gases are catalyzed before being reintroduced at the engine inlet. Reformed gases contain carbon monoxide and hydrogen in addition to carbon dioxide, steam and nitrogen dioxide that compose usual recirculated gases. In order to compare EGR and RGR concepts, the study is divided in three stages. Firstly, a “two-zone” thermodynamic model has been developed and validated on a large open chamber SI engine (18L CHP plant engine, fuelled by natural gas and equipped with data acquisition). Both in-cylinder pressure and NOx emissions have been compared between numerical results and experimental data. A good agreement is obtained, the error is less than 3%. Secondly, a widespread model of steam reforming on a Ni/MgOAl2O3 catalyst has been used to compute in particular CO and H2 concentrations. Numerical results lead to a good concordance with experimental data from literature. Finally, SI engine and reformer models have been linked. RGR and EGR configurations have been numerically compared considering the same recirculation mass flow rate. According to the results, RGR is the best way to decrease significantly nitrous oxide emissions, while keeping good engine performance.

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