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A new instrument for measurement of diesel in-cylinder radiation heat transfer has been designed, calibrated, and tested in a single cylinder, open chamber, turbocharged diesel engine. The unique feature of the instrument is that it measures the total radiation flux over the entire hemisphere, rather than being restricted to a finite acceptance angle of less than 2π steradians as have previous instruments. The paper gives the instrument design details and shows that a combination of polycrystalline alumina and sapphire gives an optimum receiver optics design. However a solution to the problem of bonding these two materials was not found. Thus an all polycrystalline alumina receiver was used in the prototype instrument. Results using the prototype show that keeping the receiver free of soot is a problem for an all polycrystalline alumina design. Data were thus corrected for window deposits by post-experiment calibration of the dirty receiver.

Measurement of oil film thickness between piston rings and cylinder liner was conducted on a single cylinder version of a Cummins L-10 diesel engine using a laser induced fluorescence technique. The oil was illuminated with blue laser light (λ=442 nm) that causes the oil to fluoresce at a longer characteristic wavelength (λ=500 nm). This fluorescent light intensity is proportional to oil film thickness. A single fiber (50 μm core) was used to carry the laser light to the oil and to return the fluorescent light back to a photomultiplier tube. The paper presents results of oil film thickness measured under motored engine conditions for varying engine speeds, intake boost pressures and cylinder liner temperatures. The following conclusions were drawn from the experimental data. Oil film thickness increases with engine speed showing hydrodynamic lubrication. An increase in liner temperature decreases oil film thickness.