The Diesel as a High-Output Engine for Aircraft 380137
FROM single-cylinder engine tests, power and fuel-consumption curves have been calculated for a highly boosted multicylinder Diesel engine. The influence of inlet-air temperature and maximum cylinder pressure on attainable mean effective pressure for a given specific fuel consumption is demonstrated. Theoretical Diesel-cycle performance curves are included to show gains possible by further improvement and control of combustion rates. Performance to be expected from the two-stroke-cycle Diesel is estimated.
It is concluded that the boosted four-stroke-cycle Diesel engine can exceed the maximum sea-level output of the 100-octane gasoline engine and give lower specific fuel consumptions at any power output. A similar comparison holds for the altitude performances of the two types, although the Diesel will impose greater demands on the air blower. Adoption of the turboblower by the Diesel engine offers further advantages. Greatly increased outputs for a given specific fuel consumption result as inlet-air temperatures are reduced, indicating the desirability of more efficient blowers or improved aftercoolers. Further substantial gains in performance are possible if materials, bearings, and design technique are improved to allow of higher cylinder pressures. The two-stroke-cycle engine offers a decrease in engine weight per horsepower at the expense of somewhat increased fuel consumption.