Electrically driven turbos

[titan2782]

No, not the ebay special that promise 1 psi

Thinking about turbo lag and heat problems. Part of the heat issue and lag is the way the turbine is spun - with exhaust. Why not make the turbo more like a centrifugal supercharger but instead of spinning the turbine with the belt or exhaust, why not spin it with an electric motor? Electric motors are good enough to drive hybrids. They have no torque curve, it's instant torque from 0 - infinity RPM's. The turbine could spin instantly and make lag a thing of the past.

I can't see any parasitic loss occurring from powering a motor. I'm sure some smart people could come up with something. So why havent we? You wouldn't need all that complex piping and you'd reduce the heat and lag.

Why not? I'm not an engineer so tell me where my thinking is flawed.

[H3LLON3ARTH]

No, not the ebay special that promise 1 psi

Thinking about turbo lag and heat problems. Part of the heat issue and lag is the way the turbine is spun - with exhaust. Why not make the turbo more like a centrifugal supercharger but instead of spinning the turbine with the belt or exhaust, why not spin it with an electric motor? Electric motors are good enough to drive hybrids. They have no torque curve, it's instant torque from 0 - infinity RPM's. The turbine could spin instantly and make lag a thing of the past.

I can't see any parasitic loss occurring from powering a motor. I'm sure some smart people could come up with something. So why havent we? You wouldn't need all that complex piping and you'd reduce the heat and lag.

Why not? I'm not an engineer so tell me where my thinking is flawed.

The thing I see wrong with it would be loss of mpg due to it not reusing non burnt fuel and the power would be therw but you would have to design it differently than anything we've seen then how would you lubricate the turbine and also you have to think how long will the electric motor last compared to normal turbos and the heat would still be therw due to friction just not like it is with exhaust.

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[titan2782]

The thing I see wrong with it would be loss of mpg due to it not reusing non burnt fuel and the power would be therw but you would have to design it differently than anything we've seen then how would you lubricate the turbine and also you have to think how long will the electric motor last compared to normal turbos and the heat would still be therw due to friction just not like it is with exhaust.

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Turbo's do not recycle unburnt fuel. It may ignite inside of the turbine to help propel it, but it does not make it's way back into the engine. Any unburnt fuel will recirculated through any emissions system (e.g. the EGR).

1) How do centrifugal superchargers lubricate themselves? Last one I dealt with had ceramic bearings that were doused in oil.
2) The turbo would remain the same. The only different is that a motor would drive the turbine instead of exhaust.
3) What makes you think an electric motor wouldn't outlast the engine?

Maybe I should restate my question to "Electrically powered centrifugal supercharger". Maybe the "turbo" aspect is causing confusion.

[XtremeRevolution]

It never worked in the past because you simply needed MUCH too much power and large electric motors with banks of batteries. That said, you might be able to get away with less on such a small displacement motor if you're only using it to reduce turbo lag.

However, a pulley driven and clutch-engaged (similar to an A/C compressor) centrifugal turbine would be in my opinion a better option.

[titan2782]

It never worked in the past because you simply needed MUCH too much power and large electric motors with banks of batteries. That said, you might be able to get away with less on such a small displacement motor if you're only using it to reduce turbo lag.

However, a pulley driven and clutch-engaged (similar to an A/C compressor) centrifugal turbine would be in my opinion a better option.

pulley driven systems are limited by RPM and pulley size (multiplication). if you had an electric motor driving it, you could control the motor to provide a custom profile not achievable with a pulley drive.

Banks of batteries? While I agree that a beefy alternator or some other power supply would be needed, I don't think it would be that extreme But again, I have no idea. I don't see it being done and there has to be a reason.

I'm sure we could easily do some math and determine what kind of motor would be needed and it's requirements.

[jblackburn]

Think a leafblower motor to spin at an RPM even remotely useful just to prevent lag. Them things are ginormous and super loud.

Turbos spin at upwards of 100,000 RPM under full boost. Superchargers are roughly 1/2 that. Few big electric motors go that fast.

[XtremeRevolution]

pulley driven systems are limited by RPM and pulley size (multiplication). if you had an electric motor driving it, you could control the motor to provide a custom profile not achievable with a pulley drive.

Banks of batteries? While I agree that a beefy alternator or some other power supply would be needed, I don't think it would be that extreme But again, I have no idea. I don't see it being done and there has to be a reason.

I'm sure we could easily do some math and determine what kind of motor would be needed and it's requirements.

Indeed, pulley driven systems are limited by RPM, but you won't need much to alleviate turbo lag. Keep that in mind. This is simply a complement to the existing turbo.

It has been done before, and it did require a bank of batteries and three large motors. You simply don't have enough electricity for sustained use to produce the amount of constant pressure you would need. That, and you also have to make it worth the extra weight you're adding.

Thomas Knight Turbo Electric Supercharger - Tech Review - Turbo Magazine

[jblackburn]

Besides, there's better turbo technologies out there that can help reduce or prevent lag.

BMW uses two small turbos to provide consistent power throughout the rev range. Ford's diesel uses twin-scroll turbos that essentially incorporate a small and large turbocharger into one for both low-end power (and little lag) and good top-end power. Dodge's diesel uses a variable geometry turbocharger with movable fins to get the same effect.

Both may become commonplace as gasoline engines continue to be downsized and the technology comes down in price/up in reliability.

[Dale_K]

Electric supercharging technology exists. Here is a link to a story on the Society for Automotive Engineers website.

Valeo's electric supercharger targeted for 2015-16 production

[XtremeRevolution]

Electric supercharging technology exists. Here is a link to a story on the Society for Automotive Engineers website.

Valeo's electric supercharger targeted for 2015-16 production

It would be interesting to see how much those will cost, and where they're getting the 2,000W of power from.