Search Results

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.

A brake has been designed for use on a class 8 tractor trailer which utilizes a hydrodynamic film of fluid between a series of rotors and stators to reduce wear and increase energy rejection capability. The hydrodynamic film brake or HFB was constructed and tested on a brake dynamometer and demonstrated a very low parasitic loss at all speeds and a high energy rejection rate. Deceleration rates of a 10,450 kg (23,000lb) inertially simulated axle were 6 M/S2 (20 ft/s2) with the application of 0.618 MPa (90 PSI) air pressure. These tests demonstrated the feasibility of meeting the braking requirements for class 8 vehicles with a wet disc brake. Test results indicated very low wear rates for in service operation and good heat rejection characteristics.