“If the air spring is not leaking and adding pumping losses, where is the efficiency lost?”
Heat. Compressing air raises its temperature, the heat flows out and is lost energy. During expansion, it absorbs heat. Flowing heat is energy transfer. So where does the energy come from to heat the expanded air. Etc. It’s why running an engine via compressed air is not cost effective. Compressing it loses energy, expansion is inefficient, too.
ButI want to see what my bud says. I’m not a thermo expert.
I email pinged a buddy of mine, a thermo guy, to get his comments.
—”Heat. Compressing air raises its temperature, “
No disagreement.
“HEAT, THE GRAVEYARD OF ENERGY”, or something like that?
I was almost awake in that class; it was early.
Recalling the notorious Cadillac 8-6-4 among others.
Variable displacement via fuel management.
I’m doubting the influence on the system.
Guessing as usual and, do not actually know.
PLS help!
Variable displacement via fuel management.
How could anyone forget the goofy valve covers? (I DID!)
They had a solenoid that deactivated the valves keeping them closed, pumping loss, and all that stuff.
The Jake brake!
And compression release on racing bikes...
—”A detailed study of a cylinder activation concept by efficiency loss analysis and 1D simulation”
...In most of the current cylinder deactivation designs, both the air and the fuel supply are switched off for the inactive cylinders. For this purpose, usually the intake and exhaust valves of these cylinders are deactivated, which eliminates the gas exchange losses. In addition, the gas trapped inside the deactivated cylinders acts as a pneumatic spring, resulting in only minor in-cylinder process losses, mainly due to heat transfer to the combustion chamber walls. As there are no gas forces due to combustion in the deactivated cylinders and piston, lateral forces are, therefore, significantly reduced, friction loss is also comparatively low...
https://link.springer.com/article/10.1007/s41104-020-00070-1