Compression-Ignition Engine Performance at Altitude 370154
ENGINE-TEST results are presented for simulated altitude conditions using a displacer-piston combustion-chamber on a 5-in. by 7-in. single-cylinder compression-ignition engine operating at 2000 r.p.m.
Comparison between maximum performance at altitude of the compression-ignition engine and a carburetor engine showed that the compression-ignition engine had a slight power advantage for the same conditions of inlet air. However, if the carburetor air is heated to prevent icing, the compression-ignition engine inducting the colder and more dense air of altitude will have a decided advantage over the carburetor engine.
Analysis of the results for which the inlet-air temperature and pressure were varied independently indicates that maximum engine performance cannot be corrected reliably either on an inlet-air-density or weight-of-air-charge basis. Maximum engine power increases with inlet-air pressure and decreases with temperature very nearly as straight lines. Correction factors are suggested accordingly.