Why Engine Variables Affect Exhaust Hydrocarbon Emission

Daniel, W. A.

doi:10.4271/700108

Cited by 69 publications

(5 citation statements)

References 11 publications

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“…However, experimental uncertainty, especially in In Figure 8, hydrocarbon emissions are shown to increase as the mixture was leaned or as compression ratio was increased. Both of these trends are in agreement with previous studies (Daniel, 1970;Patterson and Henein, 1972). One factor which can generate higher hydrocarbon emissions, as the engine is leaned, is the increased (MBT) spark advance.…”

Section: Exhaust Emissionssupporting

confidence: 93%

“…One factor which can generate higher hydrocarbon emissions, as the engine is leaned, is the increased (MBT) spark advance. Daniel (1970) has shown that advanced spark timing results both in greater density of hydrocarbons in combustion chamber crevices and in reduced oxidation of the hydrocarbons within the exhaust system. Another factor is the increased compression ratio which produces both increased quench and crevice hydrocarbons and reduced exhaust after-reaction (Daniel, 1970).…”

Section: Exhaust Emissionsmentioning

confidence: 99%

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Evaluation of acetylene as a spark ignition engine fuel

Hilden

Stebar

1979

Int. J. Energy Res.

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In spite of its known shortcomings as a fuel for spark ignition engines, acetylene has been suggested as a possible alternative to petroleum‐based fuels since it can be produced from non‐petroleum resources (coal, limestone and water). Therefore, acetylene was evaluated in a single‐cylinder engine to investigate performance and emission characteristics with special emphasis on lean operation for NOx control. Testing was carried out at constant speed, constant airflow and MBT spark timing. Equivalence ratio and compression ratio were the primary variables. The engine operated much leaner when fuelled with acetylene than with gasoline. With acetylene, the engine operated at equivalence ratios as lean as 0·53 and 0·43 for compression ratios of 4 and 6, respectively. However, the operating range was very limited. Knock‐induced preignition occurred either with compression ratios above 6 or with mixtures richer than 0·69 equivalence ratio. Both the indicated thermal efficiency and power output were less for acetylene fuelling than for gasoline. Acetylene combustion occurred at sufficiently lean equivalence ratios to produce very low NOx and CO emissions. However, when the low NOx levels were achieved hydrocarbon control was not improved over that with gasoline. Despite the potential for NOx control demonstrated in this study of acetylene fuelling, difficulties encountered with engine knock and preignition plus well‐known safety problems (wide flammability limits and explosive decomposition) associated with acetylene render this fuel impractical for spark ignition engines.

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Section: Exhaust Emissionssupporting

confidence: 93%

Section: Exhaust Emissionsmentioning

confidence: 99%

Evaluation of acetylene as a spark ignition engine fuel

Hilden

Stebar

1979

Int. J. Energy Res.

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“…An excellent example of the value of practical applications using one-dimensional simulations is that of flame quenching on the internal walls of engine combustion chambers. As late as 1970, 68 the common belief in the automobile industry was that flame quenching on spark-ignition (SI) engine combustion chamber walls was responsible for a significant fraction of the unburned hydrocarbon emissions from such engines. However, shortly after the earliest development of detailed kinetic mechanisms for methane, ethane, acetylene, and methanol (by about 1980), laminar flame modeling of the ''head-on collision'' of a laminar flame with a cooled solid combustion chamber wall demonstrated that, while a quench layer near the engine wall is indeed produced, the fuel in that quench layer rapidly diffuse out to the hot, stationary flame zone away from the wall and are almost entirely consumed.…”

Section: Comprehensive Mechanisms and Mechanism Validation Experimentsmentioning

confidence: 99%

Multi-fuel surrogate chemical kinetic mechanisms for real world applications

Westbrook

Mehl

Pitz

et al. 2018

Phys. Chem. Chem. Phys.

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The most important driving force for development of detailed chemical kinetic reaction mechanisms in combustion is the desire by researchers to simulate practical systems. This paper reviews the parallel evolution of kinetic reaction mechanisms and applications of those models to practical, real engines. Early, quite simple, kinetic models for small fuel molecules were extremely valuable in analyzing long-standing, poorly understood applied ignition and flame quenching problems, and later kinetic models have been applied to much more complex flame propagation, problems including autoignition in spark-ignition engines and issues related to octane numbers and knock in modern, high compression ratio and other engines. The recent emergence of very large, multi-fuel surrogate kinetic mechanisms that can address many different fuel types and real engine applications is discussed as a modern analytical tool that can be used for a wide variety of practical applications.

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“…Using measured pCB) data from Daniel (1970), Cf was computed and compared to exhaust concentrations for eleven different cases encompassing five engine operating parameters: fuel-air ratio, airflow, spark timing, compression ratio, and engine speed. The trends of the computed results agreed very well with the corresponding trends of the mea sured exhaust concentrations.…”

Section: Model Performancementioning

confidence: 99%

A Statistical Analysis of the Influence of Cyclic Variation on the Formation of Nitric Oxide in Spark Ignition Engines

Chen

Krieger

1976

Combustion Science and Technology

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A statistical method is presented to study the influence of cyclic variation of the combustion process on the formation of nitric oxide in spark ignition engines. In the analysis which was done for this paper, each engine cycle was treated as a real ization of a random experiment. Specifically, the cylinder pressure as a function of crank angle was considered a stochastic proce ss, and the nitric oxid e concentration frozen in the expansion stroke was considered a random variable associated with the random experiment.A set of consecutive cylinder pressure-crank angle data furnished the statistical properties of the cylinder pressure of a spa rk ignition engine at a normal running condition. The stochastic process of cylinder pressure was first approximated by one degree of randomness expression with peak combustion pressure as the characterizing random variable. Secondly, a combustion and nitric oxide kinetics model was used to establish the functional relationship of frozen nitric oxide concentration to cylinder pressure, particularly to the peak combustion pressure. Finally, the probability density function of the nitric oxide concentration was calculated by using the fundamental theorem of functions of random variables.

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Why Engine Variables Affect Exhaust Hydrocarbon Emission

Cited by 69 publications

References 11 publications

Evaluation of acetylene as a spark ignition engine fuel

Evaluation of acetylene as a spark ignition engine fuel

Multi-fuel surrogate chemical kinetic mechanisms for real world applications

A Statistical Analysis of the Influence of Cyclic Variation on the Formation of Nitric Oxide in Spark Ignition Engines

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