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The Fuel stratification process has been investigated in the cylinder of an axially stratified lean burn engine by visualizing fuel behavior. Planar laser light sheet from an Nd:YAG laser has been illuminated through the transparent quartz cylinder of a single cylinder optical engine. Mie scattered light has been captured through the quartz window in the piston head with an ICCD camera. Fuel has been replaced with an ethanol droplets to utilize an atomized fuel spray for visualization purposes. Swirl ratios have been varied by changing cylinder heads with different swirl numbers and injection time has been varied to find the effect of fuel stratification. A higher lean mixture limit was achieved when the fuel remained at the combustion chamber as stratified with the proper combination of fuel injection timing swirl flow.

The mechanism of axial stratification was investigated in a port injection SI engine. The port swirl and tumble number characterized the ports. The experiment consisted of a steady flow rig test for defining flow characteristics, engine test for finding lean misfire limit, fuel behavior tracing in a steady flow rig for the understanding basic stratification, fuel motion visualization in motored engine for the investigating real stratification process and flame capturing under known stratified conditions. The results show that not only swirl but also tumble affects axial stratification with the interaction of injection timing. It was also observed that stable initial flame improved engine stability by stratification, but the flame propagation pattern and direction was not affected by stratified condition, load, air-fuel ratio and fuel phase but by bulk in-cylinder flow pattern.

Nowadays the use of clean fuel on vehicles is actively studied to prevent air pollution in cities. Because of this social need, KIA has developed various vehicles that use alternative fuels[1,2,3,4]. In this study the development of a CNG (Compressed Natural Gas) vehicle that was converted from a 2.0 ℓ Sportage, multi-purpose vehicle, is described. The development of its engine, the conversion of the vehicle, its EMS (Engine Management System), and the reduction of its emissions are discussed.

An experimental study of the effect of spark power on the growth rate of spark-ignited flame kernels was conducted in a turbulent flow system at 1 atm, 300 K conditions. All measurements were made with premixed, propane-air at a fuel/air equivalence ratio of 0.93, with 0%, 8% or 14% dilution. Two flow conditions were studied: a low turbulence intensity case with a mean velocity of 1.25 m/sec and a turbulence intensity of 0.33 m/sec, and a high turbulence intensity case with a mean velocity of 1.04 m/sec and a turbulence intensity of 0.88 m/sec. The growth of the spark-ignited flame kernel was recorded over a time interval from 83 μsec to 20 msec following the start of ignition using high speed laser shadowgraphy.