Oppo... I've had an idea.

"shpuker" (shpuker) 04/04/2014 at 12:19 • Filed to: None

0

33

So. I was looking through the Mercedes clever little turbo split and hit a strange idea....

Take out the compressor all together, run the turbine as a generator with electric motors at each of the front wheels. Could run batteries in the footwells. Not sure how much energy you'd be able to get out of the system without causing back-pressure issues, however I want to say it'd see similar energy gains as a traditional turbo, just in different form.

Reigntastic > shpuker 04/04/2014 at 12:24

0

People have made electric powered turbos before, it's something in development currently iirc

RamblinRover Luxury-Yacht > shpuker 04/04/2014 at 12:24

1

Probably not, at least at steady state. Depends, though - friction losses in a turbo+compressive losses (power that isn't really getting into the engine, basically) would have to be more than generating losses, transmission losses, battery losses, and electric motors losses + efficiency losses due to weight and efficiency effects on the engine.

It's not like similar things haven't been tried, though - there have been experimental drivetrains that had an exhaust-driven snail mechanically linked to the drive system. That was a failure, though experience tells us that tends to be more lossy than an electric system, despite being lighter.

505Turbeaux > Reigntastic 04/04/2014 at 12:25

1

and superchargers, but I think he was talking about using a similar turbine to spin a generator and using that juice to run the front wheels

davedave1111 > shpuker 04/04/2014 at 12:26

0

Compressing the intake air effectively increases the size of your engine, allowing you to burn more fuel and get more power out. That's where the majority of the 'extra' power comes from. So you'd possibly be recovering as much energy from the (smaller) exhaust flow as a conventional turbo, but that isn't all that much compared to the extra power made by burning extra fuel.

Reigntastic > 505Turbeaux 04/04/2014 at 12:27

1

Very true. What would power the turbine, though? Just air intake? As long as it was a nice ball bearing setup I can see it working.

Not a bad way to get power out of a normally unused source, pretty novel way to charge a battery really.

RamblinRover Luxury-Yacht > davedave1111 04/04/2014 at 12:29

0

I recall some kind of NA engine with a mechanically linked t0 drive exhaust snail that was experimental - I don't think it did very well.

shpuker > Reigntastic 04/04/2014 at 12:32

1

An electric turbo runs basically the inverse of what a system like this would attempt. I'm sure I'm not the first person to pose the question though.

shpuker > RamblinRover Luxury-Yacht 04/04/2014 at 12:33

0

Very true. It'd be interesting to try and work it out and see what the gains/losses look like.

HammerheadFistpunch > shpuker 04/04/2014 at 12:33

0

its called electric turbo compounding

shpuker > davedave1111 04/04/2014 at 12:33

0

I'm aware. It'd certainly have power loss at the turbine however if say there was the potential to set up a system that could disconnect the turbine under acceleration, re-engage it at cruising speed, etc. then theres the potential for efficient power storage. I'd have to actually crunch a shit load of numbers to be able to figure the fuel economy hit, power loss, energy storage, weight gains, fuel hit from weight gain, etc. BUT! It's an idea.

505Turbeaux > Reigntastic 04/04/2014 at 12:34

0

sounded like using exhaust to spin the turbine, if they can split the turbine and compressor sides, I think you could use the power left over from spinning the compressor side to run the generator too . I would think an obstruction in the intake, especially at those velocities would affect power too much. Although, you do have a point there

Frank Grimes > shpuker 04/04/2014 at 12:35

0

Put a supercharger on a shaft with belt between the two turbo halves.

shpuker > HammerheadFistpunch 04/04/2014 at 12:37

0

That's pretty damn close isn't it. Damn. They've got an interesting setup going with that.

Best I can tell theirs runs a turbo charged engine normally, but connects the shaft to a generator, and then adds another shaft-generator connection at the crank. So not quite the same concept. Unless I'm missing something, entirely possible.

Bad Idea Hat > shpuker 04/04/2014 at 12:37

0

In the same vein, using a system like this in a gas-engined car, with the batteries providing power to an electric motor to provide early, instant, high torque acceleration would be amazing.

It seems like it would be insanely complicated, though.

HammerheadFistpunch > shpuker 04/04/2014 at 12:39

0

They use a turbo and a turbo compound, I had this same idea fly into me head a few years ago and so I went hunting to see if it had been done. There is one large truck maker with one in production, but I can't remember who it is.

shpuker > Frank Grimes 04/04/2014 at 12:39

0

If this hasn't been done, then I don't care how mundane and inefficient it may be, I want to do it. Just to say I did.

shpuker > Bad Idea Hat 04/04/2014 at 12:42

0

I'll draw something up later to try and visualize it. Seems like it could be possible though.

shpuker > HammerheadFistpunch 04/04/2014 at 12:42

0

Interesting. I'll have to read that over more carefully when I get time.

Reigntastic > 505Turbeaux 04/04/2014 at 12:47

1

Backpressure from exhaust could interfere with power too, though. Either way it's kind of a roundabout way to make power.

Mattbob > HammerheadFistpunch 04/04/2014 at 12:59

0

heck yeah John Deere! Can't wait to see this on a lawnmower. Or maybe a John Deere F1 team is in the works??????????

shpuker > HammerheadFistpunch 04/04/2014 at 13:38

0

Ok so by the looks of it they're running a VGT turbo normally and then further down the line they have a second turbine as a generator. Not the same but also clever. I'll try and draw up what I'm thinking

HammerheadFistpunch > shpuker 04/04/2014 at 13:43

0

something like this?

shpuker > HammerheadFistpunch 04/04/2014 at 13:55

0

Isn't that just an electric driven turbo?

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > HammerheadFistpunch 04/04/2014 at 14:59

0

been done without the electric before. They had very high power density and excellent efficiency, but were deemed too complex, heavy, and un-reliable for successfull airplane use...

the Wright R-3350 actually saw use in production aircraft, but was not as extreme an implementation as the Napier Nomad engines.

HammerheadFistpunch > shpuker 04/04/2014 at 15:30

0

you're right, I googled compound electric turbo and got this and didn't look closely. Same concept just reverse the roles

HammerheadFistpunch > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t 04/04/2014 at 16:54

0

I've actually seen that engine. Turbo compounding is very interesting to me, especially electric turbo compounding as it takes a lot of the benefit of mechanical turbo compounding and removes the really problematic parts, mainly the gearing required to make a 150,000 rpm turbine jive with 5000 rpm engines.

davedave1111 > shpuker 04/04/2014 at 21:21

0

What I was trying to say is that the energy a normal turbo extracts from the exhaust is just what's used to pump air into the engine at higher pressure. The engine then uses that to burn fuel, just like normal, to create big gobs of luvverly power.

Axial > shpuker 04/05/2014 at 03:19

0

Bulbs like these are becoming illegal to produce.

In a generation or two, people will forget what it means when an item features a light bulb as its iconogaphy.

shpuker > davedave1111 04/05/2014 at 14:15

0

Yes and the amount of energy required to slowly trickle charge some lithium ions wouldn't be much different, and in fact might actually be lower. In theory though something like a small 3 cyl. running a split turbo with a small power generator along the impeller could operate at say 90% of its normal efficiency and store enough battery power during a 15 minute city commute to make the same commute back home running off pure electric power. Now make it a plug in, maybe you never even need to run the engine on your commute. But then when you want to go for a drive or a road trip, you have the potential for the say 130-150hp engine to be supplemented with 30-50 hp and a nice bit of torque from a pair of electric motors.

Fuel economy average would be through the roof and it might not even be that shitty to drive. Hell make it a 3-cyl. diesel. 100mpg highway, double that city due to electric power, and maintain a 0-60 under 8 or 9 seconds? Ultimate commuter car.

davedave1111 > shpuker 04/05/2014 at 14:44

0

I still think you've missed the point. The turbo on a small 3 cyl helps add ~50bhp, maybe, but it doesn't extract all that from the exhaust. In fact, it's probably only taking a few bhp at most that way. It then uses that to spin a compressor, forcing air into the engine and allowing it to generate loads more power. Once you factor in conversion losses, any gains by using a turbine in the exhaust to generate electric power would be minimal.

shpuker > davedave1111 04/06/2014 at 16:13

0

Tell that to every F1 team currently doing basically that... I know how a turbo works. I know the drag it creates, and I have a reasonable idea of how much torque is required to spin a small power generator. Extra drag would be relatively negligible. Think something like, high compression 1.0L 3cyl making 110hp on its own, now add in 12psi intake pressure from the turbo and you should see something more like 150-170hp. Subtract pressure loss due to spinning this generator and maybe you drop to 11.5psi, so now you're at 145-160hp and you're storing battery power quite regularly.

davedave1111 > shpuker 04/06/2014 at 16:16

0

I don't think I've understood what you're saying, then. Didn't you start by getting rid of the compressor?

shpuker > davedave1111 04/06/2014 at 16:35

0

See the other thread. I drew both up side by side. the compressorless idea isn't as practical but would still create fairly minimal drag which could probably be overcome with some clever exhaust work.