The influence of fluid motion on flame kernel development and cyclic variation in a spark ignition engine

Conference · Sun Jan 01 04:00:00 EST 1989

OSTI ID:7036242

Hall, M J ^[1]

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1. Combustion Applications Div., Sandia National Labs, Livermore, CA (US)

The author reports on examination of the effect of engine flow field characteristics on cycle-to-cycle variation in a methane fueled engine. The rate of early flame development was correlated with the turbulence characteristics and the mean flow. This, in turn, was correlated with engine performance characteristics such as peak cylinder pressure. Drastically different flow field characteristics were achieved in the engine through the use of a prechamber having a variable inlet orifice diameter. Three combustion chamber geometries were examined: main chamber combustion without a prechamber, a prechamber with a 27 mm entrance orifice. Measurements of mean velocity and turbulence intensity were made in the region of the spark using laser Doppler velocimetry. The engine had a compression ratio of 5.1 and was operated at speeds of 300, 600, and 1200 rpm. The equivalence ratios were 0.7 and 0.8. A newly developed fiber optic spark plug probe was used to measure early flame development. It was found that the rate of early flame development increased with increasing turbulence intensity. It was determined that for lean operation, the development of the early flame is critical to subsequent combustion. Under most operating conditions a strong correlation was found between how quickly the flame grew to a diameter of 1 cm and the peak cylinder pressure and crank angle of peak cylinder pressure.

• OSTI ID: 7036242
• Report Number(s): CONF-8904240--
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
092000 -- Biomass Fuels-- Combustion-- (1990-)
33 ADVANCED PROPULSION SYSTEMS
330101* -- Internal Combustion Engines-- Spark-Ignition
330800 -- Emission Control-- Alternative Fuels
42 ENGINEERING
420400 -- Engineering-- Heat Transfer & Fluid Flow
ALKANES
CHEMICAL REACTION KINETICS
COMBUSTION CHAMBERS
COMBUSTION KINETICS
CYLINDERS
ENGINES
FLAME PROPAGATION
FLUID FLOW
GEOMETRY
HEAT ENGINES
HYDROCARBONS
INTERNAL COMBUSTION ENGINES
KINETICS
MATHEMATICS
MEASURING INSTRUMENTS
METHANE
ORGANIC COMPOUNDS
PRESSURE GRADIENTS
REACTION KINETICS
SPARK IGNITION ENGINES
TURBULENT FLOW
VELOCIMETERS