Purely hypothetical discussion ahead. Turn back all ye who may say "this is stupid!"
If an exhaust turbine and wastegate are installed on our engine, what is an example of turbine shaft torque and speed? How much energy (temperature and pressure above atmospheric) can be used for regeneration?
Two options for generating power:
- gear down heavily and employ a high-output alternator
- run a DC electric motor in reverse
Similarly, can an intake compressor be run from a DC motor? Not talking the tiny electric superchargers on eBay... I'm talking voltage step-up + 1/2 hp dc motor + centrifugal/twin screw compressor (a la Vortech).
The idea has been tossed around by Subaru:
HERE for the next WRX.
I'm just trying to wrap my head around how challenging this would be.
Potential issues:
- Sizing a battery/capacitor bank
- Management of alternator clutching
- Management of battery/capacitor bank discharge rate
- Integrated BOV with instant pressure relief (compressor motor braking)
- Cost and hardware weight would be high.
Potential awesome:
- No lag, as long as you've got battery power.
- Boost pressure can be closely controlled via dedicated feedback controller.
- The system can be switched to "ECO" mode for regenerating energy to supplement the alternator (would require an isolator for starting battery).
- The system can be switched off completely.
- Combination of the above. ECO mode during low load, low rpm driving. Instantly switch on above X% load.
Comments? Discussion?