05/01198 Prediction of knock limited operating conditions of a natural gas engine

2005 ◽  
Vol 46 (3) ◽  
pp. 179
Keyword(s):  
Natural Gas ◽  
Operating Conditions ◽  
Gas Engine ◽  
Natural Gas Engine

Response surface method optimization of a natural gas engine with dedicated exhaust gas recirculation

2021 ◽  
pp. 146808742199652
Author(s):  
Chris A Van Roekel ◽  
David T Montgomery ◽  
Jaswinder Singh ◽  
Daniel B Olsen
Keyword(s):  
Natural Gas ◽  
Operating Conditions ◽  
Exhaust Gas ◽  
Effective Pressure ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Indicated Mean Effective Pressure ◽  
Surface Method ◽  
Rsm Optimization ◽  
Gas Recirculation

Stoichiometric industrial natural gas engines rely on robust design to achieve consumer driven up-time requirements. Key to this design are exhaust components that are able to withstand high combustion temperatures found in this type of natural gas engine. The issue of exhaust component durability can be addressed by making improvements to materials and coatings or decreasing combustion temperatures. Among natural gas engine technologies shown to reduce combustion temperature, dedicated exhaust gas recirculation (EGR) has limited published research. However, due to the high nominal EGR rate it may be a technology useful for decreasing combustion temperature. In previous work by the author, dedicated EGR was implemented on a Caterpillar G3304 stoichiometric natural gas engine. Examination of combustion statistics showed that, in comparison to a conventional stoichiometric natural gas engine, operating with dedicated EGR requires adjustments to the combustion recipe to achieve acceptable engine operation. This work focuses on modifications to the combustion recipe necessary to improve combustion statistics such as coefficient of variance of indicated mean effective pressure (COV of IMEP), cylinder-cylinder indicated mean effective pressure (IMEP), location of 50% mass fraction burned, and 10%–90% mass fraction burn duration. Several engine operating variables were identified to affect these combustion statistics. A response surface method (RSM) optimization was chosen to find engine operating conditions that would result in improved combustion statistics. A third order factorial RSM optimization was sufficient for finding optimized operating conditions at 3.4 bar brake mean effective pressure (BMEP). The results showed that in an engine with a low turbulence combustion chamber, such as a G3304, optimized combustion statistics resulted from a dedicated cylinder lambda of 0.936, spark timing of 45° before top dead center (°bTDC), spark duration of 365 µs, and intake manifold temperature of 62°C. These operating conditions reduced dedicated cylinder COV of IMEP by 10% (absolute) and the difference between average stoichiometric cylinder and dedicated cylinder IMEP to 0.19 bar.

Combustion Analysis of a Natural Gas Engine

2003 ◽  
Author(s):  
Seref Soylu
Keyword(s):  
Natural Gas ◽  
Burning Rate ◽  
Equivalence Ratio ◽  
Operating Conditions ◽  
Engine Fuel ◽  
Ignition Timing ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Rate Analysis ◽  
Propagation Period

A two-zone thermodynamic model was developed for a spark ignition natural gas engine. The model was used to calculate instantaneous mass burning rate and thermodynamic state of burned and unburned zones of the combustion chamber content. Cylinder pressure data was collected at various engine operating conditions. Natural gas and natural gas–propane mixtures were used as engine fuel. From the burning rate analysis various combustion characteristics, such as flame initiation period (FIP) and flame propagation period (FPP) were calculated at various engine operating conditions. It was observed that both the FIP and FPP decrease with increasing equivalence ratio for lean mixtures. While the retarded timing decreases the FIP, the FPP has a tendency to increase. Addition of propane to natural gas reduces the FPP although the FIP is not affected. Unburned and burned gas temperatures are significantly raised with increase in equivalence ratio. However, ignition timing and propane fraction do not influence the temperatures as much as equivalence ratio does.

Characterization of Particulate Matter Emissions From a 4-Stroke, Lean-Burn, Natural Gas Engine

2007 ◽  
Author(s):  
Kris Quillen ◽  
Maren Bennett ◽  
John Volckens ◽  
Rudolf H. Stanglmaier
Keyword(s):  
Particulate Matter ◽  
Natural Gas ◽  
Internal Combustion Engines ◽  
Geometric Mean ◽  
Operating Conditions ◽  
Particulate Emissions ◽  
Scanning Mobility Particle Sizer ◽  
Health And Environmental Effects ◽  
Gas Engine ◽  
Natural Gas Engine

Regulatory agencies are becoming increasingly concerned with particulate emissions as the health and environmental effects are becoming better understood. While much research has been performed on diesel engines, little is known about particulate matter (PM) emissions from natural gas internal combustion engines. In this project, tests were conducted on a Waukesha VGF F18 natural gas engine running at full load. PM10 combustion emissions were collected on Teflon and quartz filters and a scanning mobility particle sizer (SMPS) was used to determine the particle size distribution. Tests were performed at 4, 5, 6, and 7% exhaust oxygen (O2) levels. Overall, it was found that a large number of small particles were emitted from this engine. The total mass based PM emissions were found to be 0.0148 gm/bkW-hr, which is slightly greater than the tier-4 nonroad diesel particulate emissions standard. Particle distributions revealed that the geometric mean diameter (GMD) of the natural gas particles was approximately 30 nm and did not change with air to fuel ratio. Particulate concentrations were found to decrease at leaner engine operating conditions. Results showed a strong correlation between the NOx and particle concentrations, while an inverse correlation between CO and particle concentrations was revealed.

Effect of Stationary Natural Gas Engine Oils on Fuel Economy

2012 ◽  
Author(s):  
Nikhil Dayanand ◽  
John D. Palazzotto ◽  
Alan T. Beckman
Keyword(s):  
Natural Gas ◽  
Fuel Consumption ◽  
Fuel Economy ◽  
Operating Conditions ◽  
Specific Fuel Consumption ◽  
Engine Oil ◽  
Brake Specific Fuel Consumption ◽  
Oil Viscosity ◽  
Gas Engine ◽  
Natural Gas Engine

In order to investigate the possible environmental and economic benefits of lubricants optimized for stationary natural gas engine efficiency, a decision was made to develop a test stand to quantify the effects of lubricant viscosities and formulations on the brake specific fuel consumption. Many fuel economy tests already exist for evaluating gasoline and heavy duty diesel motor oils which have proven the benefit of fuel economy from different lubricant formulations. These engines would not be suitable tools for evaluating the fuel economy performance of lubricating oils formulated specifically for stationary natural gas engines, since there are significant differences in operating conditions, fuel type, and oil formulations. This paper describes the adaptation of a Waukesha VSG F11 GSID as a tool to evaluate fuel consumption performance. The performance of brake specific fuel consumption when using different formulations was measured at selected high loads and rated speed. The results of the testing program discuss the viscosity and additive effects of stationary natural gas engine oil formulations on brake specific fuel consumption. The results will detail the change in brake specific fuel consumption between natural gas engine oil formulations blended to varying viscosities and compared to a typical natural gas engine oil formulation with a viscosity of 13.8 cSt @ 100°C. The second portion of the test program explores the effect of different additive packages that were blended to the same finished oil viscosity. It was acknowledged that there were statistical differences in brake specific fuel consumption characteristics between lubricants different in viscosity and additive formulations.

Characterization of Particulate Matter Emissions From a Four-Stroke, Lean-Burn, Natural Gas Engine

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Kris Quillen ◽  
Maren Bennett ◽  
John Volckens ◽  
Rudolf H. Stanglmaier
Keyword(s):  
Particulate Matter ◽  
Natural Gas ◽  
Internal Combustion Engines ◽  
Geometric Mean ◽  
Operating Conditions ◽  
Particulate Emissions ◽  
Emission Standard ◽  
Particulate Emission ◽  
Gas Engine ◽  
Natural Gas Engine

Regulatory agencies are becoming increasingly concerned with particulate emissions as the health and environmental effects are becoming better understood. While much research has been performed on diesel engines, little is known about particulate matter (PM) emissions from natural gas internal combustion engines. In this project, tests were conducted on a Waukesha VGF F18 natural gas engine running at full load. PM10 combustion emissions were collected on teflon and quartz filters and a scanning mobility particle sizer was used to determine the particle size distribution. Tests were performed at 4–7% exhaust oxygen (O2) levels. Overall, it was found that a large number of small particles were emitted from this engine. The total mass based PM emissions were found to be 0.0148gm∕bkWh, which is slightly greater than the Tier-4 nonroad diesel particulate emission standard. Particle distributions revealed that the geometric mean diameter of the natural gas particles was approximately 30nm and did not change with air to fuel ratio. Particulate concentrations were found to decrease at leaner engine operating conditions. Results showed a strong correlation between the NOx and particle concentrations, while an inverse correlation between CO and particle concentrations was revealed.

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