Investigations of combustion in ''squish'' chamber spark ignition engines

Conference · Wed Feb 01 04:00:00 EST 1984 · Am. Soc. Mech. Eng., (Pap.); (United States)

OSTI ID:6423312

James, E H

Seemingly inexplicable and intractable observations relating to flame travel time behaviour in 'squish' chambered, spark ignition (S.I.) engines are resolved using a computer model of the combustion process coupled with hot wire anemometry techniques for flow velocity measurements under 'motored' conditions. ''Reverse squish'' is shown to be present during the early part of the expansion stroke and, under certain conditions, this radically reduces combustion intervals in the engine through augmenting the expansion velocity component of flame speed. Mass burning rates are not correspondingly increased however indicating that there is no automatic correlation between flame speeds and turbulence intensities. Computer modelling of the combustion process is shown to provide much more detail than can be obtained from experiments. This technique is used to explain the relative insensitivity of flame travel times part-way across the chamber to compression ratio variation and turbulence level. The pressure dependency of laminar burning velocity as recommended by Mattavi et al is shown to be highly important in this context as also are the increased expansion velocities at the lower compression ratios. A mechanism is suggested whereby overall flame travel times at the end of combustion finally decrease with compression ratio increase to comply with normally observed trends.

• Research Organization: Department of Mechanical Engineering, Loughborough University of Technology, Loughborough, Leicsetershire
• OSTI ID: 6423312
• Report Number(s): CONF-840201-
• Conference Information: Journal Name: Am. Soc. Mech. Eng., (Pap.); (United States) Journal Volume: 84-DGP-10
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330101* -- Internal Combustion Engines-- Spark-Ignition
CHEMICAL REACTION KINETICS
COMBUSTION CHAMBERS
COMBUSTION KINETICS
COMPRESSION RATIO
COMPUTERIZED SIMULATION
ENGINES
FLAMES
FLOW RATE
FLUID FLOW
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
KINETICS
PRESSURE DEPENDENCE
REACTION KINETICS
SIMULATION
SPARK IGNITION ENGINES
TURBULENT FLOW