Premixed mixture ignition in the end-gas region (PREMIER) combustion in a natural gas dual-fuel engine: operating range and exhaust emissions

This paper is concerned with engine experiments and spectroscopic analysis of premixed mixture ignition in the end-gas region (PREMIER) combustion in a pilot fuel ignited, natural gas dual-fuel engine. The results reveal the characteristics and operating parameters that induce and affect this combustion mode. The PREMIER combustion is followed by natural gas flame propagation. Pilot-injected diesel fuel ignites the natural gas/air mixture, and the flame propagates before the natural gas/air mixture is autoignited in the end-gas region. This combustion cycle differs from a knocking cycle in terms of combustion and emission characteristics. The PREMIER combustion can be controlled by pilot fuel injection timing, the equivalence ratio, and the exhaust gas recirculation (EGR) rate, and can be used as an effective method for high load extension on a dual-fuel engine. An analysis of the relationship between the maximum in-cylinder pressure and its crank angle (CA) is used to compare combustion dynamics during conventional, PREMIER, and knocking combustion. In PREMIER combustion, the heat release gradually transforms from the slower first-stage flame rate to the faster second-stage rate. During PREMIER combustion, the maximum indicated mean effective pressure (IMEP) and thermal efficiency increase by about 25 per cent compared with those of conventional combustion, and low carbon monoxide (CO) and total hydrocarbon (HC) emissions can be achieved. However, nitrogen oxide (NO x ) emissions increase. Spectroscopic analysis shows that the intensity of the OH* emissions in the end-gas region increases as the combustion mode transforms from conventional to PREMIER to knocking. In all three modes, emission fluctuations above 650 nm can be observed in the end-gas region. These emissions are attributed to the luminosity from soot particles formed during the concurrent diesel fuel combustion.

[1]  Takayuki Adachi,et al.  OS-A1: Effects of High Boost and High EGR on the Super Clean Diesel Engine : Evaluation using the Transient Test Cycle(OS-A High Efficiency and Low Emission Engine by Variable Mechanism,Organized Session Papers) , 2008 .

[2]  A. G. Gaydon.  The spectroscopy of flames , 1957 .

[3]  Masayuki Kobayashi,et al.  OS-A2: Diesel Combustion by means of Variable Valve Timing in a Single Cylinder Engine(OS-A High Efficiency and Low Emission Engine by Variable Mechanism,Organized Session Papers) , 2008 .

[4]  C. M. Coats,et al.  Investigation of the ignition and combustion of n-heptane-oxygen mixtures , 1979 .

[5]  Martin Berzins,et al.  End Gas Inhomogeneity, Autoignition and Knock , 1998 .

[6]  N Ladommatos,et al.  Optical diagnostics for soot and temperature measurement in diesel engines , 1998 .

[7]  Eiji Tomita,et al.  Effect of EGR on Combustion and Exhaust Emissions in Supercharged Dual-Fuel Natural Gas Engine Ignited with Diesel Fuel , 2009 .

[8]  A. Abdel-azim.  Fundamentals of Heat and Mass Transfer , 2011 .

[9]  Alan Williams,et al.  A shock-tube investigation of the ignition of lean methane and n-butane mixtures with oxygen , 1969 .

[10]  R. J. Nichols,et al.  1993 Soichiro Honda Lecture: The Challenges of Change in the Auto Industry: Why Alternative Fuels? , 1994 .

[11]  P. Gaskell,et al.  Burning Velocities, Markstein Lengths, and Flame Quenching for Spherical Methane-Air Flames: A Computational Study , 1996 .

[12]  J. Warnatz,et al.  Detection of hot spots in the end gas of an internal combustion engine using two-dimensional lif of formaldehyde , 1994 .

[13]  Teruhiro Sakurai,et al.  Study on Lean Burn Gas Engine Using Pilot Oil as the Ignition Source , 2001 .

[14]  Halim G. Santoso,et al.  Managing SI/HCCI Dual-Mode Engine Operation , 2005 .

[15]  Norimasa Iida,et al.  Autoignition and Combustion of Natural Gas in 4 Stroke HCCI Engine , 2001 .

[16]  M. Schreiber,et al.  Development of a New Measurement Technique for the Investigation of End-Gas Autoignition and Engine Knock , 1996 .

[17]  Ghazi A. Karim,et al.  Combustion in Gas Fueled Compression: Ignition Engines of the Dual Fuel Type , 2003 .

[18]  R. Hernberg,et al.  Experimental Determination of Spontaneous Diesel Flame Emission Spectra in a Large Diesel Engine Operated with Different Diesel Fuel Qualities , 1998 .

[19]  William J. Pitz,et al.  The Autoignition Chemistry of Paraffinic Fuels and Pro-Knock and Anti-Knock Additives: A Detailed Chemical Kinetic Study , 1991 .

[20]  Frank P. Incropera,et al.  Fundamentals of Heat and Mass Transfer , 1981 .

[21]  H. Shoji,et al.  Analysis of OH radical emission intensity during autoignition in a 2-stroke SI engine , 1999 .

[22]  J. Eng,et al.  Characterization of Pressure Waves in HCCI Combustion , 2002 .

[23]  John E. Dec,et al.  Boosted HCCI for high power without engine knock and with ultra-low NOx emissions - Using conventional gasoline , 2010 .

[24]  C. G. W. Sheppard,et al.  A Theoretical and Experimental Study of the Modes of End Gas Autoignition Leading to Knock in S. I. Engines , 1994 .

[25]  Yong Li,et al.  Influence of Different Volume Percent Hydrogen/Natural Gas Mixtures on Idle Performance of a CNG Engine , 2008 .

[26]  Bengt Johansson,et al.  Investigation of the Early Flame Development in Spark Assisted HCCI Combustion Using High Speed Chemiluminescence Imaging , 2007 .

[27]  K. Maruyama,et al.  Combustion in a Supercharged Biomass Gas Engine with Micro-Pilot Ignition -Effect of Injection Pressure and Amount of Diesel Fuel- , 2007 .

[28]  Deming Jiang,et al.  Determination of laminar burning velocities for natural gas , 2004 .

[29]  Eiji Tomita,et al.  Auto-ignited kernels during knocking combustion in a spark-ignition engine , 2007 .

[30]  Takuji Ishiyama,et al.  Performance and Exhaust Emissions in a Natural-Gas Fueled Dual-Fuel Engine. , 2000 .

[31]  Tang-Wei Kuo,et al.  Experimental metrics for identifying origins of combustion variability during spark-assisted compression ignition , 2008 .

[32]  Eiji Tomita,et al.  Effects of EGR and Early Injection of Diesel Fuel on Combustion Characteristics and Exhaust Emissions in a Methane Dual Fuel Engine , 2002 .

[33]  Eiji Tomita,et al.  Effect of fuel injection parameters on engine performance and emissions of a supercharged producer gas-diesel dual fuel engine , 2009 .

[34]  Christopher S. Weaver,et al.  Natural Gas Vehicles - A Review of the State of the Art , 1989 .