So I've got this idea for spooling a turbo with an electric motor that I'm thinking about using as a senior design project. My idea is to connect a small electric motor to the turbo shaft between the center section and compressor with with a series of gears. There would be a small gear on the shaft itself that has dog slots or friction material on one side, and another gear concentric with the shaft gear that would ride on a sleeve over the turbo shaft that would allow this gear to slide back and forth while staying in contact with the electric motor gearbox. There would be mating dogs or friction materal on one side of this gear that would allow the two gears to engage and disengage. A solinoid attached to a fork that pushes on the gearbox connected gear would provide the engagement and disengagement. This would work much like the clutch fork. I would use a microcontroller to control engagement and disengagement points, motor speed, and anything electronic I left out through inputs from a hall-effect sensor in the gearbox, TPS signal, and engine RPM.

This contraption would allow the two gears to mate and then power transferred from the electric motor until the turbo reached operating speed or enough exhaust energy became availble to outpace the electric motor and sustain boost. The solinoid would disengage and the gears would seperate, allowing the turbine to spin freely and the electric motor to shut off. This design should only create axial loads, as forces normal to the turbo shaft would quickly destroy the bushings.

I know it might be very hard to visualize this without a sketch or detail drawing, but would this be be feasible? I know it would take quite a bit of power to spool a turbo such as a GT42R or something of similar size up quickly with just an electric motor, but there would still be energy from the exhaust present. I'm also not sure just how much force the turbo bearings could withstand either.

Can anyone give me some ideas as to how much power would be required to help spool a GT42R on a streetported 13BT by 3000 rpm? Can anyone point out any glaring flaws or give me some constructive critism? I've left quite a few details out, maybe I'll post a sketch later.

 

Im not sure if this is helpfull or not, but this thread came to mind. I know he talked of using an electric motor to get boost with his design so maybe theres some usefull info there?

 

How about a shaft with socket on the end directly connected to the compressor nut.

Then a one way bearing (Sprague clutch) in the Turbo Inlet Duct at the correct location for the shaft.

Put a high rpm DC motor on the other end of the one way bearing to spin it up.

Electric RC airplane guys have some motors that can spin the needed ~100,000rpm with some real volts put to it.

Or you can find other ways to spool turbo very fast. There was a thread about someone using steam/water injected into the exhaust side for a real boost.