An Experimental Study of the Cyclic Variability in Spark Ignition Engines

1996 ◽  
Author(s):  
Nir Ozdor ◽  
Mark Dulger ◽  
Eran Sher
Keyword(s):  
Experimental Study ◽  
Spark Ignition ◽  
Spark Ignition Engines ◽  
Cyclic Variability

scholarly journals A Fast CFD-Based Methodology for Determining the Cyclic Variability and Its Effects on Performance and Emissions of Spark-Ignition Engines

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4131
Author(s):  
George M. Kosmadakis ◽  
Constantine D. Rakopoulos
Keyword(s):  
Spark Ignition ◽  
Pollutant Emissions ◽  
Computational Time ◽  
Spark Ignition Engines ◽  
Cyclic Variability ◽  
Indicated Mean Effective Pressure ◽  
Spark Plug ◽  
Performance And Emissions ◽  
Si Engines ◽  
Cyclic Variations

A methodology for determining the cyclic variability in spark-ignition (SI) engines has been developed recently, with the use of an in-house computational fluid dynamics (CFD) code. The simulation of a large number of engine cycles is required for the coefficient of variation (COV) of the indicated mean effective pressure (IMEP) to converge, usually more than 50 cycles. This is valid for any CFD methodology applied for this kind of simulation activity. In order to reduce the total computational time, but without reducing the accuracy of the calculations, the methodology is expanded here by simulating just five representative cycles and calculating their main parameters of concern, such as the IMEP, peak pressure, and NO and CO emissions. A regression analysis then follows for producing fitted correlations for each parameter as a function of the key variable that affects cyclic variability as has been identified by the authors so far, namely, the relative location of the local turbulent eddy with the spark plug. The application of these fitted correlations for a large number of engine cycles then leads to a fast estimation of the key parameters. This methodology is applied here for a methane-fueled SI engine, while future activities will examine cyclic variations in SI engines when fueled with different fuels and their mixtures, such as methane/hydrogen blends, and their associated pollutant emissions.

Theoretical and Experimental Study of the Fuelling a Truck Diesel Engine with Liquefied Petroleum Gas

2016 ◽  
Vol 822 ◽  
pp. 198-205
Author(s):  
Nikolaos Cristian Nutu ◽  
Constantin Pana ◽  
Alexandru Dobre ◽  
Niculae Negurescu ◽  
Alexandru Cernat
Keyword(s):  
Experimental Study ◽  
Diesel Engine ◽  
Spark Ignition ◽  
Experimental Investigations ◽  
Spark Ignition Engines ◽  
Nitric Oxides ◽  
Liquefied Petroleum Gas ◽  
And Storage ◽  
Objective Research ◽  
Engine Power

The increasing price of the fuels and tightening of the pollution rules requires the use of some efficient fuelling methodes with altenative fuels for diesel engines. Fuelling with LPG of a diesel engine is a viable sollution, considering that it can be used the infrastructure for distribution and storage already used for spark ignition engines. In this work are presented results of theoretical and experimental investigations of a truck diesel engine fuelled with LPG by diesel-LPG methode. The main objective research is the decrease of the nitric oxides emissions with the premise that the engine power is maintained at the same level like in the case of the standard engine, fuelled only with diesel fuel.

Article

1999 ◽  
Vol 77 (7) ◽  
pp. 1177-1190 ◽  
Author(s):  
S Taconnet ◽  
Y Simon ◽  
G Scacchi ◽  
F Baronnet
Keyword(s):  
Experimental Study ◽  
Reaction Mechanisms ◽  
Reaction Medium ◽  
Spark Ignition ◽  
Reaction Vessel ◽  
Spark Ignition Engines ◽  
Flow Reaction ◽  
Oxidation Mechanisms

The different behaviour of hydrocarbons with respect to autoignition phenomena is, at present, not yet fully explained. We have therefore investigated the oxidation of two alkanes that have different octane numbers: neopentane (85.5) and isopentane (92.3), to obtain a better understanding of their reaction mechanisms, in particular, those reactions that are responsible for the onset of knock in spark ignition engines. The experimental study was performed at 873 K in a jet-stirred flow reaction vessel. The oxidation mechanisms were simplified by using the CHEMKIN programme of simulation of reaction mechanisms. These mechanisms were compared to those accounting for the oxidation of n-pentane, cyclopentane, n-heptane, and isooctane that we have previously studied. This comparison shows that the different behaviour of these hydrocarbons can be explained, at least in part, by the presence, in the reaction medium, of resonance-stabilized radicals.Key words: oxidation, neopentane, isopentane, autoignition, modelling.

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