Spark Plug Location Research Articles

Flow direction characteristics in the vicinity of the spark plug in an S. I. Engine

The flame speed may be decomposed into the burning speed and the flame transport speed. The flame transport speed is affected considerably by the flow direction, variation rate of flow direction, and flow speed in the combustion chamber. Especially, the flow direction and the variation rate of flow direction at the spark plug location during the ignition period have an important effect on the ignition process and the early flame propagation process. We measured the flow direction component and the variation rate of flow direction with a hot wire probe at the spark plug location. It was shown that the representative flow direction of ignition period is the right-vertical direction of crank shaft and it was used to investigate the variation rate of flow direction.

Effect of combustion duration on the performance and emission characteristics of a spark ignition engine using hydrogen as a fuel

The deteriorating quality of air due to exhaust emissions and the increasing number of motor vehicles in the world, is sending alarming waves throughout the world to try to do something to cut off or significantly reduce these emissions in order to save our planet. Scientists have found that hydrogen presents the best and unprecedented solution to this problem, for its superior combustion qualities and availability. This paper discusses analytically one aspect of combustion i.e. combustion duration and how it is affected by an engine’s operating parameters like compression ratio, equivalence ratio, spark plug location, spark timing and engine speed, and how it affects an engine’s performance parameters like brake specific fuel consumption, brake mean effective pressure, thermal efficiency, as well as emission characteristics.

99/03854 Performance enhancement in coal fired thermal power plants. Part I: boilers: Bhatt, M. S. and Jotribasu, S. Int. J. Energy Res., 1999, 23, (6), 465–487

Results from multidimensional numerical simulations and cycle simulations are presented in an effort to optimize the performance of a fuel-lean-burn, homogeneous charge, natural gas spark-ignition internal combustion (IC) engine. The multidimensional numerical simulations are performed using modified versions of the KIVA-2 and KIVA-3 computer codes. The engine cycle simulations are performed using the WAVE code. The KIVA codes are enhanced with a turbulent combustion submodel which employs a two-step, natural gas/air chemical kinetics scheme with a temperature-dependent activation energy, together with a modified eddy dissipation model to treat the effects of turbulence on the burning rate. The output from the multidimensional calculations is used, in a novel way, as input to the WAVE cycle simulation code to predict overall engine performance. The Caterpillar G3400 and G3500 fuel-lean-burn natural gas engines are the specific engines under study. The predictions for brake specific fuel consumption (BSFC) are within 1% of the measured values for all cases where engine data are available. The effects of swirl, combustion chamber geometry, and spark location on burning rate and BSFC are investigated. Specifically, the results show that: (1) the numerical predictions are in good qualitative and quantitative agreement with engine data; (2) there is an optimum initial swirl ratio for the central bowl, central spark plug geometry; (3) an offset bowl results in a lower BSFC than a central bowl for the same initial swirl ratio and spark plug location; and (4) an offset spark plug results in a lower BSFC than a central plug for the same initial swirl ratio.

A numerical study of natural gas combustion in a lean burn engine

Results from multidimensional numerical simulations and cycle simulations are presented in an effort to optimize the performance of a fuel-lean-burn, homogeneous charge, natural gas spark-ignition internal combustion (IC) engine. The multidimensional numerical simulations are performed using modified versions of the KIVA-2 and KIVA-3 computer codes. The engine cycle simulations are performed using the WAVE code. The KIVA codes are enhanced with a turbulent combustion submodel which employs a two-step, natural gas/air chemical kinetics scheme with a temperature-dependent activation energy, together with a modified eddy dissipation model to treat the effects of turbulence on the burning rate. The output from the multidimensional calculations is used, in a novel way, as input to the WAVE cycle simulation code to predict overall engine performance. The Caterpillar G3400 and G3500 fuel-lean-burn natural gas engines are the specific engines under study. The predictions for brake specific fuel consumption (BSFC) are within 1% of the measured values for all cases where engine data are available. The effects of swirl, combustion chamber geometry, and spark location on burning rate and BSFC are investigated. Specifically, the results show that: (1) the numerical predictions are in good qualitative and quantitative agreement with engine data; (2) there is an optimum initial swirl ratio for the central bowl, central spark plug geometry; (3) an offset bowl results in a lower BSFC than a central bowl for the same initial swirl ratio and spark plug location; and (4) an offset spark plug results in a lower BSFC than a central plug for the same initial swirl ratio.

Torch Ignition: Ideal for Lean Burn Premixed-Charge Engines

Sluggish flame initiation and propagation, and even potential misfiring, become major problems with lean-fueled, premixed-charge, spark-ignited engines. This work studies torch ignition as a means for improving combustion, fuel economy, and emissions of a retrofitted, large combustion chamber with nonideal spark plug location. A number of alternative configurations, employing different torch chamber designs, spark-plug locations, and materials, were tested under full-load and part-load conditions. Results indicate a considerable extension of the lean operating limit of the engine, especially under part-load conditions. In addition, torch ignition can lead to substantial thermal efficiency gains for either leaner or richer air-fuel ratios than the optimum for the conventional ignition system. On the richer side, in particular, the torch-ignited engine is capable of operating at maximum brake torque spark timings, rather than compromised, knock-limited spark timings used with conventional ignition. This translates into thermal efficiency improvements as high as 8 percent at an air-fuel ratio of 20:1 and full load.

Effects of Spark Plug Number and Location in Natural Gas Engines

Combustion experiments were conducted on a spark-ignited single-cylinder engine operating on natural gas. A special open chamber cylinder head was designed to accept as many as four spark plugs. Data were obtained to investigate the effects of spark plug quantity and location on NOx, HC, CO emissions, brake and indicated thermal efficiency, MBT timing, combustion duration, ignition delay, peak cylinder pressure, peak cylinder temperature, and heat release over a wide range of equivalence ratios.

The variation of in-Cylinder Mixture Ratios during Engine Cranking at Low Ambient Temperatures

The development of mixture conditions in the cylinder of a fuel-injected spark ignition engine during engine cranking has been investigated at ambient temperatures down to —20°C. Mixtures near to the spark plug location were sampled and analysed to determine the air-fuel ratio and the relative proportions of light, medium and heavy components in the fuel. At low temperatures, the local air-fuel ratio varies substantially during the compression stroke, as does mixture composition. The change in mixture ratio over successive cycles of cranking depends on the fuel injected per cycle and the fuel-transfer characteristics of the intake port. The success or failure of combustion initiation is observed to depend only on the mixture air-fuel ratio at the spark plug. The upper limit on this mixture ratio for successful first-fire appears to be near to 35 : 1 by mass. Air-borne fuel in the cylinder accounts for only a small percentage of that supplied by the injector.

A fundamental study on direct-injection stratified charge combustion.

An experimental study has been made on stratified charge combustion which may possibly realize lean combustion in a speak ignition engine. In order to simulate charge stratification, methane was injected into a constant volume vessel, and its temporal and spatial concentrations were measured using a hot wire probe. Thus, fuel distribution maps were drawn throughout the vessel for successive timings after fuel injection. Then, ignitability was determined for various spark plug locations and related to the measured stratified charge. The results have shown that a local mixture exceeding its flammable limit for mean fuel-air ratio can be ignited with a proper turbulence of fuel concentration and that for fast burning of the whole charge, spark ignition should be made at a downstream point of the fuel jet.

Characteristic time ignition model extended to an annular gas turbine combustor

The extension of the ignition model to an annular combustor was successful and a single ignition limit curve for three engines was developed. The correlation also includes 4 geometries and 2 plug locations for the AGT-1500, 30 fuels covering a wide range of volatilities from gasoline to No. 6 fuel oil and viscosities of 0.3-75 x 10/sup -6/ m/sup 2//s, inlet air temperatures of 240-330 K, and pressures of 30-140 kPa. One significant difference that developed in examining the F101 data is that the primary zone equivalence ratio was the proper equivalence ration for the F101 as opposed to the assumption of a constant equivalence ratio at the spark gap for the AGT-1500 and T-63. This may indicate better mixing of the fuel spray with the primary zone air in the F101 due to the injection of the fuel into the primary and secondary swirler air. The critical features of applying the ignition model to gas turbine combustors are the drop size estimates via empirical equations and the equivalence ratio evaluations based on the fuel spray and spark plug locations.