One of the problems I have with turbocharging is with the method used to moderate the boost level, the wastegate.
Wasting energy at the very time it is most needed.
With a variable speed/volume SC no "wastegate" equivalent would be needed.
No "room" for batteries, etc, in an airplane, LSA, so trying to find a way to run a small engine in two modes efficienctly, BIG and little.
~2500 RPM limitation.
Look at, consider, the differential driving the SC as a "summing" device. If one input is spinning at 3000 RPM and the other input is also spinning at 3000 RPM in the "opposite" direction then the output shaft will be stationary. Simply "lock" the electric motor in place and the output drive...
New...NEWS...!!
The VVT-i description for the 2010 RX450H and Prius is now available at techinfo.toyota.com.
The newest hybrid engine designs actually use VVT-i to move the intake valve opening delay into and out of the Atkinson cycle mode. With low engine loads/loading, low charge going into...
I strongly suspect that Superchargers are not more commonly used because up to now there was no obvious way to have the engine be the primary SC driving force but still have variability of SC speed/boost independent of engine speed.
Studebaker did this in back in the mid-fifties in their Golden...
Isn't there some "law" that says if you want to compress a given volume of air to a specific pressure level it ALWAYS take an equal amount of energy...??
Other than parasitic losses how is it possible for a turbocharger to be more efficient than a SuperCharger...??
Or let's take a simpler...
Now that we know, have verified, that the power to spin a turbo need not otherwise be wasted...
If you're going to put "power" into spinning a turboharger why not instead put an equal level of power into spinning a positive displacement SC...??
No turbo lag whatsoever, the expansion ratio can...
"...why even care.."
Because in order to spin the turbine portion of the turbocharger a significant level of power must go into the exhaust manifold. Since the Atkinson or Miller cycle engines make greater use of the combustion of the air/fuel mixture there is little likelihood of having enough...
globi5:
Good read, but keep in mind that this was for a cogeneration engine and did not need to operate throughout the RPM and power range of the typical automotive environment.
Text also makes it quite plain that tubocharging is NOT compatible with the Miller cycle for automotive use...
Other than the fact that Mr. Miller already incoporated, incorporates, the Atkinson cycle as a "building block" for the Miller cycle engine your description sounds pretty exacting of my theory.
And it appears to me that unless the engine is a 4 cylinder or multiples thereof the SC must be of...
"...fat chance...if the engine....an acceptable power output..."
Again, the idea is to use the highly fuel efficient Atkinson cycle mode at those times an "acceptable" power output is NOT required. Then when an "acceptable" level of power IS required then made use of the variable speed aspect...
There are two parts to the issue. First of all the rate of travel of the piston is not linear. As the crank leaves the BDC position the amount of angular motion is quite high but the level of piston motion is relatively low. The DIVC technique removes the requirement for any level of compression...
"..I don't think you can change..."
But, why not...??
4 cylinder Atkinson cycle engines exist, work, and are in current production and use.
Miller cycle engines exist, work, and are in current use.
DFI engines exist, work, and are in current production and use.
Engines with VVT and VVT-i...
