Can supercharging of an engine ever lead to reduced power?

[chetanladha]

Hi,

I have decided to increase inlet T and P of a typical diesel engine (operatiing on dual air standard cycle).

THeoretically if all other parameters r same, I have observed that t2 (temp at the end of compression) and p2 increases, but t3 (temp at the end of constant volume heating) and t4 (temp at the end of constant pressure heating) tend to decrease because of increased p2.

This fall in temperatures result in reduced efficiency and power output.

Can any1 confirm if this is really true? As Practically, supercharging is supposed to boost the power o/p..

Thanks in advance

 

[DaveC426913]

Why would t3 and t4 decrease because of increased pressure?

 

[chetanladha]

constant volume process.

ratio of t3 to t2 = ratio of p3 to p2

p2 increases = t3 decreases

t4 is a function of t3..

 

[chetanladha]

Sorry i forgot 2 mention

THANKS FOR UR RESPONSE..

 

[xxChrisxx]

Yes output can decrease, if you have poor inlet geometry or injectors that arent big enough, you'll be spending power compressing air that you then can't use for combustion.