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Motorcycle engine braking was measured in each forward gear for a cross-section of typical street motorcycles. Using GPS data acquisition and video, deceleration relative to speed was examined. Motorcycle characteristics included various engine displacements and types of motorcycle. The data acquired will give more insight into the extent which engine braking is a factor for deceleration, a topic which has not been addressed in a peer-reviewed journal article to this date.

The challenge of designing a very small cylinder for a high-performance four-stroke-cycle, avgas-fueled spark-ignition engine is described. Measures for minimizing the performance compromises associated with severely down-scaled cylinder geometry are indicated. A Burt McCollum sleeve valve is shown to facilitate a favorable four-stroke-cycle combustion chamber layout. A single-cylinder engine is featured with synchronized port fuel injection, variable energy CD ignition, top-cold liquid cooling, seal-less centrifugal coolant pump, dry-sump pressure lubrication and one-piece connecting rod with plain bearings. Actual size and weight figures are given. The shaft output and fuel consumption estimates presented are derived from computer simulation.

A diesel engine of unconventional configuration and construction is described with particular reference to general aviation propulsion application. The technical approach is justified and some supporting development experience is described. Some details are presented for a specific engine design to serve an aircraft application that requires 630 shaft horsepower at an altitude of 10,000 feet. This six-cylinder turbocharged engine displacing 9.0 liters was estimated to weigh 755 lb. and develop 980 BHP at sea level with a specific consumption of less than 0.36 lb./BHP-hr.

A method for analyzing and evaluating the potential atmospheric ozone formed by the actual emissions of carbon monoxide and volatile organic compounds from motor vehicles is described. The method is illustrated using the results of some recently published emission tests performed on a variety of vehicles equipped to utilize gasoline and several alternative fuels including methanol, ethanol, alcohol/gasoline blends, LPG and CNG. The reactivity contributions of the various constituent species as well as the overall ozone potential of the emissions are determined. Some of the scientific and application issues raised by the method are also discussed including the effects of nitrogen oxide concentrations, varying airshed characteristics, emission standards and test procedures.

The prospect of monitoring in-service particulate emissions of transit buses by examining the cumulative records of engine-lubricating-oil solids was investigated. This possibility was suggested by the observation that the same particulates emitted from engine exhaust also enter the engine crankcase. To test this hypothesis, four in-service metropolitan transit buses were selected for their varying exhaust-smoke levels. The relationship between lubricating-oil solids to exhaust opacity levels was investigated by evaluating the results of some periodic oil-analysis and smoke-opacity tests. This evaluation is presented along with the procedures used to obtain the data. The specifications and in-service operating profiles of the buses are also described. The evaluation revealed a sufficiently strong correlation between opacity and total suspended solids in the engine lubricating oil to warrant further development with a view to practical applications.

The art of supplementary-fueling Diesel-powered highway vehicles is reviewed. Some theoretical considerations and experimental results are presented as a guide to future application. Supplementary fueling is differentiated from pilot injection, and some of the limitations, potential problem areas and control design considerations are discussed. The use of propane (LPG) as a supplementary transportation fuel is compared with other candidate fuels, and opportunities for improving truck-engine performance, durability, economy, fuel tolerance, emissions and drive-ability are discussed.