For comparison of Diesel- and Otto-engine cycles: (a) Show that the thermal efficiency of the air-standard Diesel
Question:
For comparison of Diesel- and Otto-engine cycles:
(a) Show that the thermal efficiency of the air-standard Diesel cycle can be expressed as
where r is the compression ratio and rc is the cutoff ratio, defined as rc = VA/VD. (See Fig. 8.10.)
(b) Show that for the same compression ratio the thermal efficiency of the air-standard Otto engine is greater than the thermal efficiency of the air-standard Diesel cycle.
(c) If γ = 1.4, how does the thermal efficiency of an air-standard Otto cycle with a compression ratio of 8 compare with the thermal efficiency of an air-standard
Diesel cycle with the same compression ratio and a cutoff ratio of 2? How is the comparison changed if the cutoff ratio is 3?
Fig. 8.10
Step by Step Answer:
Introduction To Chemical Engineering Thermodynamics
ISBN: 9781259696527
8th Edition
Authors: J.M. Smith, Hendrick Van Ness, Michael Abbott, Mark Swihart