.with Variable Specific Heat of Working Substance. 173 



It is to be observed that the Constant Volume, Constant 

 Pressure, and Dual Combustion Cycles are capable of some 

 modification with regard to the manner in which rejection of 

 heat is carried out, since this may take place at constant 

 volume, constant pressure, or a combination of both. If, 

 however, the factors rj v \ rj p ', and 7} m ' represent the efficiencies 

 of the modified cycles of each class, under the constant 

 specific heat assumption, then rj v , r) p , and rj m , as given by (9), 

 (10), and (11), will be the corrected efficiencies complying 

 with variable specific heat conditions. 



S^The simplicity of the expressions (9), (10), and (11), 

 together with their close approximation to truth, would appear 

 to make them of some value as standard expressions. 



Further interest attaches to the form of the expressions 

 given, by comparing them with that for the well-known 

 Carnot or Constant Temperature Cycle. This cycle is shown 



Fig. 3. 



VOLUME 



in fig. 3 from which the expression for the eflicienc} 7 is 

 readily obtained as follows : — 



=l- r r-i^(T-To) 5 



where r= — =adiabatic compression ratio ; 



.'. r) t= I i— ~^lf (1— XT) to a first approximation. (12) 



