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Torsional vibrations of an engine-powered hydraulic system were analyzed. The system consisted of: a diesel engine, spline shaft with clearance, universal joints, propeller shaft, mechanical transmission with clutch engagement, hydraulic pump, and a load. Excessive torsional vibrations resulted in propeller, spline shaft, and U-joint failures. Although the system had been adequately designed for the steady-state horsepower requirements of the pump, field failures began to occur after several systems were built and delivered. A nonlinear dynamic analysis was performed, which included variations in system parameters. The analysis revealed that two design changes would reduce the dynamic stresses. These were to increase spline clearance and to add a torsional damper to the propeller shaft.

A Minimum Cooled Engine (MCE) has been successfully run for 250 hours at rated condition of 298 kW and 1900 rpm. This engine was all metallic without any coolant in the block and lower part of the heads. Ring/liner/lubricant system and thermal loading on the liner at top ring reversal (TRR) as well as on the piston are presented and discussed. Ring/liner wear is given as well as oil consumption and blow-by data during the endurance run. Another engine build with a different top ring coating and several lubricants suggested that a 1500 hours endurance run of MCE is achievable. Rig test data for screening ring materials and synthetic lubricants necessary for a successful operation of a so-called Adiabatic Engine with the ring/ceramic liner (SiN) interface temperature up to 650°C are presented and discussed.

This paper describes a chassis-dynamometer study of sulfate formation on a catalyst-equipped automobile under steady-speed and cyclic operating conditions, with particular attention to the effects of preconditioning on sulfate emission rates. The vehicle was a 1973 Ford Torino equipped with monolithic noble metal catalysts and secondary air injection to simulate a 1975 catalytic system. The fuel used was unleaded certification gasoline with a nominal 0.025 weight percent sulfur content. The experimental program consisted of (1) protracted steady-speed driving at five different road speeds up to 60 mi/hr and at idle, ordered in such a way as to show storage/release effects and stabilized sulfate and SO2 emission rates; and (2) a series of hot-start FTP-cycle tests initiated with a cold-start FTP test. Sampling for sulfate and SO2 measurement was from a dilution tube in which the vehicle exhaust gases were diluted 10:1 with filtered air.

A study is being conducted for NASA on potential diagnostic system improvements to the Space Shuttle Main Engine (SSME). This paper reports midterm progress including: (1) the results of a failure mode review identifying key diagnostic needs; (2) the results of a survey of diagnostic techniques that might be applied to the SSME; and (3) application to the SSME of a Battelle developed tool (the Failure Information Propagation Model, or FIPM) for analysis of diagnostic needs. It is concluded that opportunities for significantly improved diagnostics exist in a number of areas. Future plans are described that are directed toward development of a diagnostics strategy and design recommendations for an improved diagnostic system for the SSME.

The wider flammable limits of methanol compared to unleaded gasoline impose additional safety concerns when storing nearly neat methanol fuels. The upper flammable limit temperatures (UFLT) of various methano1/gasoline fuels were determined. An excellent correlation between the UFLT of methanol/gasoline mixtures and their dry Reid vapor pressures (RVP) was obtained. It is now possible to predict the upper temperature limit of the flammability range of methano1/unleaded gasoline fuels from a knowledge of their dry RVPs. The lower flammable limit temperatures were also determined. A good correlation was obtained between the lower flammable limit temperature and the dry RVP.