The Ultra-Lean Partially Stratified Charge Approach to Reducing Emissions in Natural Gas Spark-Ignited Engines

2018 ◽  
pp. 29-63
Author(s):  
L. Bartolucci ◽  
E. C. Chan ◽  
S. Cordiner ◽  
R. L. Evans ◽  
V. Mulone
Keyword(s):  
Natural Gas ◽  
Stratified Charge

Partially Stratified Charge Natural Gas Combustion: A LES Numerical Analysis

2015 ◽  
Author(s):  
Lorenzo Bartolucci ◽  
Stefano Cordiner ◽  
Vincenzo Mulone ◽  
Vittorio Rocco ◽  
Edward Chan
Keyword(s):  
Numerical Analysis ◽  
Natural Gas ◽  
Gas Combustion ◽  
Stratified Charge ◽  
Natural Gas Combustion

Multi-Dimensional Modeling of Direct Natural-Gas Injection and Mixture Formation in a Stratified-Charge SI Engine with Centrally Mounted Injector

2008 ◽  
Vol 1 (1) ◽  
pp. 607-626 ◽  
Author(s):  
Mirko Baratta ◽  
Andrea E. Catania ◽  
Ezio Spessa ◽  
Lothar Herrmann ◽  
Klaus Roessler
Keyword(s):  
Natural Gas ◽  
Gas Injection ◽  
Si Engine ◽  
Mixture Formation ◽  
Stratified Charge ◽  
Dimensional Modeling

scholarly journals Numerical-Experimental Comparison of the Performance of a Partially Stratified Charge Natural Gas Fuelled Engine

2004 ◽  
Author(s):  
Luca Andreassi ◽  
Stefano Cordiner ◽  
Vincenzo Mulone ◽  
C. Reynolds ◽  
R. L. Evans
Keyword(s):  
Natural Gas ◽  
Direct Injection ◽  
Numerical Data ◽  
Optimization Procedure ◽  
Complete Information ◽  
Experimental Comparison ◽  
Combustion Model ◽  
Stratified Charge ◽  
Spark Plug ◽  
Reduce Emissions

Compressed natural gas (CNG) has great potential as an alternative fuel for vehicle engines, and can reduce emissions and improve fuel economy. A single cylinder research engine has been modified to enable direct injection of a small quantity of fuel near the spark plug, independently of an overall lean homogeneous charge. Thus a partially stratified charge is formed within the chamber, which allows significant extension of the lean limit of combustion. This results in an improvement in specific fuel consumption. Numerical simulation also plays an important role in the development of such technological solutions. 3D simulations, in particular, are desirable to provide complete information about thermal and fluid dynamical fields within the chamber. In particular, among the developed numerical tools linked to the KIVA-3V code, special attention was dedicated to the formulation of the combustion model (CFM) turbulent combustion model based on the flamelet hypothesis), to adequately model non-homogeneities and lean mixture compositions. In this paper an optimization procedure is assessed, with the ultimate goal of designing combustion chambers properly devoted to be operated under lean (homogeneous and PSC) mixture conditions. The results related to the procedure definition and to its experimental validation are presented. Experimental and numerical data have been compared in terms of pressure cycles and heat release rate profiles. The overall results are encouraging, taking into special account the difficulty to reliably predict the key performance parameters without any “tuning interventions”, even when mixture richness and homogeneity were varied.

Extending the Lean Limit of Natural Gas Engines

2008 ◽  
Author(s):  
R. L. Evans
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Lean Burn ◽  
Stratified Charge ◽  
Natural Gas Engines ◽  
Spark Plug ◽  
Charge Mixture ◽  
Cyclic Variations ◽  
Lean Limit ◽  
The Stability

Two different methods to improve the thermal efficiency and reduce the emissions from lean-burn natural gas fuelled engines have been developed, and are described in this paper. One method used a “squish-jet” combustion chamber designed specifically to enhance turbulence generation, while the second method provided a partially stratified-charge mixture near the spark plug in order to enhance the ignition of lean mixtures of natural gas and air. The squish-jet combustion chamber was found to reduce Bsfc by up to 4.8% in a Ricardo Hydra engine, while the NOx – efficiency tradeoff was greatly improved in a Cummins L-10 engine. The partially stratified-charge combustion system extended the lean limit of operation in the Ricardo Hydra by some 10%, resulting in a 64% reduction in NOx emissions at the lean limit of operation. Both techniques were also shown to be effective in increasing the stability of combustion, thereby reducing cyclic variations in cylinder pressure.

The Effect of Varying the Injected Charge Stoichiometry in a Partially Stratified Charge Natural Gas Engine

2005 ◽  
Author(s):  
C.C.O. Reynolds ◽  
R.L. Evans ◽  
L. Andreassi ◽  
S. Cordiner ◽  
V. Mulone
Keyword(s):  
Natural Gas ◽  
Stratified Charge ◽  
Gas Engine ◽  
Natural Gas Engine

Natural Gas Fueled Engines Modeling under Partial Stratified Charge Operating Conditions

2017 ◽  
Author(s):  
Lorenzo Bartolucci ◽  
Stefano Cordiner ◽  
Vincenzo Mulone ◽  
Vittorio Rocco
Keyword(s):  
Natural Gas ◽  
Operating Conditions ◽  
Stratified Charge ◽  
Gas Fueled

Partially Stratified Charge Natural Gas Combustion: The Impact of Uncertainties on LES Modeling

2015 ◽  
Author(s):  
Lorenzo Bartolucci ◽  
Stefano Cordiner ◽  
Vincenzo Mulone ◽  
Vittorio Rocco ◽  
Edward Chan
Keyword(s):  
Natural Gas ◽  
Gas Combustion ◽  
Stratified Charge ◽  
Natural Gas Combustion ◽  
The Impact

Extending the Lean Limit of Natural-Gas Engines

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
R. L. Evans
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Lean Burn ◽  
Stratified Charge ◽  
Natural Gas Engines ◽  
Spark Plug ◽  
Charge Mixture ◽  
Cyclic Variations ◽  
Lean Limit ◽  
The Stability

Two different methods to improve the thermal efficiency and reduce the emissions from lean-burn natural-gas fueled engines have been developed and are described in this paper. One method used a “squish-jet” combustion chamber designed specifically to enhance turbulence generation, while the second method provided a partially stratified-charge mixture near the spark plug in order to enhance the ignition of lean mixtures of natural gas and air. The squish-jet combustion chamber was found to reduce brake specific fuel consumption by up to 4.8% in a Ricardo Hydra engine, while the NOx efficiency trade-off was greatly improved in a Cummins L-10 engine. The partially stratified-charge combustion system extended the lean limit of operation in the Ricardo Hydra by some 10%, resulting in a 64% reduction in NOx emissions at the lean limit of operation. Both techniques were also shown to be effective in increasing the stability of combustion, thereby reducing cyclic variations in cylinder pressure.

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