NO(x)-reduction by rich-lean combustion

1992 ◽  
Author(s):  
N. ZARZALIS ◽  
F. JOOS ◽  
B. GLAESER ◽  
T. RIPPLINGER
Keyword(s):  
Lean Combustion

scholarly journals Optical Investigation of a Partial Fuel Stratification Strategy to Stabilize Overall Lean Operation of a DISI Engine Fueled with Gasoline and E30

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 396
Author(s):  
Cinzia Tornatore ◽  
Magnus Sjöberg
Keyword(s):  
Volume Fraction ◽  
Direct Injection ◽  
Combustion Process ◽  
Pilot Injection ◽  
Optical Investigation ◽  
Flame Kernel ◽  
Lean Combustion ◽  
Fuel Stratification ◽  
Spark Plug ◽  
Initial Flame

This paper offers new insights into a partial fuel stratification (PFS) combustion strategy that has proven to be effective at stabilizing overall lean combustion in direct injection spark ignition engines. To this aim, high spatial and temporal resolution optical diagnostics were applied in an optically accessible engine working in PFS mode for two fuels and two different durations of pilot injection at the time of spark: 210 µs and 330 µs for E30 (gasoline blended with ethanol by 30% volume fraction) and gasoline, respectively. In both conditions, early injections during the intake stroke were used to generate a well-mixed lean background. The results were compared to rich, stoichiometric and lean well-mixed combustion with different spark timings. In the PFS combustion process, it was possible to detect a non-spherical and highly wrinkled blue flame, coupled with yellow diffusive flames due to the combustion of rich zones near the spark plug. The initial flame spread for both PFS cases was faster compared to any of the well-mixed cases (lean, stoichiometric and rich), suggesting that the flame propagation for PFS is enhanced by both enrichment and enhanced local turbulence caused by the pilot injection. Different spray evolutions for the two pilot injection durations were found to strongly influence the flame kernel inception and propagation. PFS with pilot durations of 210 µs and 330 µs showed some differences in terms of shapes of the flame front and in terms of extension of diffusive flames. Yet, both cases were highly repeatable.

Experimental Study of a 200 kW Partial Oxidation Gas Turbine (POGT) for Co-Production of Power and Hydrogen-Enriched Fuel Gas

2009 ◽  
Author(s):  
Joseph Rabovitser ◽  
Stan Wohadlo ◽  
John M. Pratapas ◽  
Serguei Nester ◽  
Mehmet Tartan ◽  
...  
Keyword(s):  
Experimental Study ◽  
Gas Turbine ◽  
Partial Oxidation ◽  
Synthesis Gas ◽  
Combustion Products ◽  
Working Fluid ◽  
Fuel Gas ◽  
Lean Combustion ◽  
Start Up ◽  
Oxidation Reactor

Paper presents the results from development and successful testing of a 200 kW POGT prototype. There are two major design features that distinguish POGT from a conventional gas turbine: a POGT utilizes a partial oxidation reactor (POR) in place of a conventional combustor which leads to a much smaller compressor requirement versus comparably rated conventional gas turbine. From a thermodynamic perspective, the working fluid provided by the POR has higher specific heat than lean combustion products enabling the POGT expander to extract more energy per unit mass of fluid. The POGT exhaust is actually a secondary fuel gas that can be combusted in different bottoming cycles or used as synthesis gas for hydrogen or other chemicals production. Conversion steps for modifying a 200 kW radial turbine to POGT duty are described including: utilization of the existing (unmodified) expander; replacement of the combustor with a POR unit; introduction of steam for cooling of the internal turbine structure; and installation of a bypass air port for bleeding excess air from the compressor discharge because of 45% reduction in combustion air requirements. The engine controls that were re-configured for start-up and operation are reviewed including automation of POGT start-up and loading during light-off at lean condition, transition from lean to rich combustion during acceleration, speed control and stabilization under rich operation. Changes were implemented in microprocessor-based controllers. The fully-integrated POGT unit was installed and operated in a dedicated test cell at GTI equipped with extensive process instrumentation and data acquisition systems. Results from a parametric experimental study of POGT operation for co-production of power and H2-enriched synthesis gas are provided.

The Research of Lean Combustion Characteristic of Compound Injection System of Direct Injection Engine

2014 ◽  
Vol 532 ◽  
pp. 362-366 ◽  
Author(s):  
Jiang Feng Mou ◽  
Rui Qing Chen ◽  
Yi Wei Lu
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Injection System ◽  
Intake Manifold ◽  
Combustion Characteristic ◽  
Injection Timing ◽  
Mixed Gas ◽  
Lean Burn ◽  
Direct Injection Engine ◽  
Lean Combustion

This paper studies the lean burn limit characteristic of the compound injection system of the direct-injection gasoline engine. The low pressure nozzle on the intake manifold can achieve quality homogeneous lean mixture, and the direct injection in the cylinder can realized the dense mixture gas near the spark plug. By adjusting the two injection timing and injection quantity, and a strong intake tumble flow with special shaped combustion chamber, it can produces the reverse tumble to form different hierarchical levels of mixed gas in the cylinder. Experimental results show: the compound combustion system to the original direct-injection engine lean burn limit raise 1.8-2.5 AFR unit.

Comparative assessment of stoichiometric and lean combustion modes in boosted spark-ignition engine fueled with syngas

2021 ◽  
Vol 239 ◽  
pp. 114224
Author(s):  
Hyunwook Park ◽  
Junsun Lee ◽  
Narankhuu Jamsran ◽  
Seungmook Oh ◽  
Changup Kim ◽  
...  
Keyword(s):  
Spark Ignition ◽  
Comparative Assessment ◽  
Spark Ignition Engine ◽  
Lean Combustion ◽  
Combustion Modes

Economy and emission characteristics of the optimal dilution strategy in lean combustion based on GDI gasoline engine equipped with prechamber

2021 ◽  
Vol 13 (12) ◽  
pp. 168781402110381
Author(s):  
Li Wang ◽  
Zhaoming Huang ◽  
Wang Tao ◽  
Kai Shen ◽  
Weiguo Chen
Keyword(s):  
Fuel Economy ◽  
Gasoline Engine ◽  
Direct Injection ◽  
Engine Performance ◽  
Gasoline Direct Injection ◽  
Dilution Ratio ◽  
Lean Combustion ◽  
Excess Air ◽  
Combustion Phase ◽  
Hc Emissions

EGR and excess-air dilution have been investigated in a 1.5 L four cylinders gasoline direct injection (GDI) turbocharged engine equipped with prechamber. The influences of the two different dilution technologies on the engine performance are explored. The results show that at 2400 rpm and 12 bar, EGR dilution can adopt more aggressive ignition advanced angle to achieve optimal combustion phasing. However, excess-air dilution has greater fuel economy than that of EGR dilution owing to larger in-cylinder polytropic exponent. As for prechamber, when dilution ratio is greater than 37.1%, the combustion phase is advanced, resulting in fuel economy improving. Meanwhile, only when the dilution ratio is under 36.2%, the HC emissions of excess-air dilution are lower than the original engine. With the increase of dilution ratio, the CO emissions decrease continuously. The NOX emissions of both dilution technologies are 11% of those of the original engine. Excess-air dilution has better fuel economy and very low CO emissions. EGR dilution can effectively reduce NOX emissions, but increase HC emissions. Compared with spark plug ignition, the pre chamber ignition has lower HC, CO emissions, and higher NO emissions. At part load, the pre-chamber ignition reduces NOX emissions to 49 ppm.

Highly Preheated Lean Combustion

2016 ◽  
pp. 63-109 ◽  
Author(s):  
A. Cavaliere ◽  
M. de Joannon ◽  
P. Sabia ◽  
G. Sorrentino ◽  
R. Ragucci
Keyword(s):  
Lean Combustion

scholarly journals The Effect of Discrete Pilot Hydrogen Dopant Injection on the Lean Blowout Performance of a Model Gas Turbine Combustor

1999 ◽  
Author(s):  
Oanh Nguyen ◽  
Scott Samuelsen
Keyword(s):  
Gas Turbine ◽  
Atmospheric Pressure ◽  
Gas Turbines ◽  
Nox Emissions ◽  
Gas Turbine Combustor ◽  
Lean Blowout ◽  
Lean Combustion ◽  
Attractive Option ◽  
Overall Performance ◽  
Model Gas Turbine Combustor

In view of increasingly stringent NOx emissions regulations on stationary gas turbines, lean combustion offers an attractive option to reduce reaction temperatures and thereby decrease NOx production. Under lean operation, however, the reaction is vulnerable to blowout. It is herein postulated that pilot hydrogen dopant injection, discretely located, can enhance the lean blowout performance without sacrificing overall performance. The present study addresses this hypothesis in a research combustor assembly, operated at atmospheric pressure, and fired on natural gas using rapid mixing injection, typical of commercial units. Five hydrogen injector scenarios are investigated. The results show that (1) pilot hydrogen dopant injection, discretely located, leads to improved lean blowout performance and (2) the location of discrete injection has a significant impact on the effectiveness of the doping strategy.

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