Electric (assisted) Turbo: Interesting info

[Logic]

Interesting eg:
Sending power to the turbo makes for faster acceleration than sending that power to the traction motor!
Who'd have thought!?

https://www.youtube.com/watch?v=R_NO0kApAqc

[Ecky]

Turbos are power multipliers. I'm not shocked.

You do of course end up burning way more fuel, and it's hard on engines. Engineering Explained is notorious for finding efficiency completely irrelevant.

[some_other_dave]

Nah, he just defines efficiency differently than we do.

He is an EV fan, though!

[Logic]

Originally Posted by Ecky

Turbos are power multipliers. I'm not shocked.

You do of course end up burning way more fuel, and it's hard on engines. Engineering Explained is notorious for finding efficiency completely irrelevant.

Sure; you're adding electrical power and fuel/air,
but engines have 'no' torque till around 4000 rpm,
whereas the traction motor has max/same torque from 0 rpm.

So I would expect max acceleration from sending the power to the traction motor initially, then perhaps sending the juice to the turbo as the engine torque/rpm increases above what the traction motor can do.
But then you lose out on the Anti Lag.

Perhaps the info in the vid is... 'incomplete'.
Perhaps the above is what Porsche would do if the battery had more oomph.
But bigger battery = more weight.

pros-n-cons, pros-n-cons...
Seems battery weight (cost?) lost in Porsche's maths?

[redpoint5]

I mean, if we're talking drag racing, you want whatever power delivery system that can deliver the limit of available traction at all speeds.

[Logic]

“We did consider doing a plug-in hybrid,” said Michael Rösler, 911 model line director, at a preview event in Stuttgart, “but that would have put 200 kilograms to 300 kilograms [440 pounds to 660 pounds] more in the car…
https://www.roadandtrack.com/news/a6...e-911-turbo-s/

That's interesting info when one is contemplating the pros and cons of small, 200 to 250cc, always on gensets in a series hybrid city cars.

[Ecky]

Originally Posted by Logic

Sure; you're adding electrical power and fuel/air,
but engines have 'no' torque till around 4000 rpm,
whereas the traction motor has max/same torque from 0 rpm.

So I would expect max acceleration from sending the power to the traction motor initially, then perhaps sending the juice to the turbo as the engine torque/rpm increases above what the traction motor can do.
But then you lose out on the Anti Lag.

Perhaps the info in the vid is... 'incomplete'.
Perhaps the above is what Porsche would do if the battery had more oomph.
But bigger battery = more weight.

pros-n-cons, pros-n-cons...
Seems battery weight (cost?) lost in Porsche's maths?

Many modern turbo engines reach peak boost before 2000rpm. Electric motors also have a lower RPM limit; the Insight's electric motor's peak torque is at just under 2000rpm, for example, because of the size of the motor and a lack of reduction gearing. Below that, it needs to use square wave vs sine wave, which (among other things) limits its power output. I can push around 10kw through it at 1000rpm, whereas at 2000rpm it's controller-limited at 25kw. Granted even 10kw of assist at 1000rpm is a lot more torque than the engine itself generates.

The batteries I have on my workbench weigh around 11kg (24lbs) (cell only) and are good for bursts of up to 53kw, or 70hp. These are around 10 years old now, and I have no doubt more modern batteries will be better in the power to weight department.

[Logic]

Originally Posted by Ecky

Many modern turbo engines reach peak boost before 2000rpm. Electric motors also have a lower RPM limit; the Insight's electric motor's peak torque is at just under 2000rpm, for example, because of the size of the motor and a lack of reduction gearing. Below that, it needs to use square wave vs sine wave, which (among other things) limits its power output. I can push around 10kw through it at 1000rpm, whereas at 2000rpm it's controller-limited at 25kw. Granted even 10kw of assist at 1000rpm is a lot more torque than the engine itself generates.

The batteries I have on my workbench weigh around 11kg (24lbs) (cell only) and are good for bursts of up to 53kw, or 70hp. These are around 10 years old now, and I have no doubt more modern batteries will be better in the power to weight department.

Yep the big advantage of electric PM motors is torque. (from 0 rpm = 0 mph)
Power = Torque x rpm.
So when the rpm number gets high, you just get more 'torques per minute'...



Thx for the battery info.
11kg is light! So light that the inverter weight adds a significant % to the total..?
Bursts of ??? seconds approximately?

Power to weight or Energy Density seems to be behind "DON'T catch fire!" atm.
That 'Mr China' has made battery fires illegal probably has something to do with that.

[Ecky]

The cells in question are Panasonic's EHW5, used in Accords as far back as 2016, Clarity, newer Insights, and the NSX.

To pull a current spec sheet requires that I sign up with an account, but some key specs:
5Ah/cell (low energy density)
Operating range: -30c to 55c
Cycle life: 50,000
Max charge/assist current: 300 amps (60C) - this is probably a 10s rating
Power density: 4.9kw/kg
Continuous charge/discharge: 40 amps (8C)
Weight (per cell): 0.229kg
3.6v nominal, 4.2v full charge

So, 60 cells in series would provide a peak and nominal voltage of 252v and 216v, would weigh 13.7kg, would have 1kwh of storage (low, good for hybrid, bad for EV), and could provide peak and continuous charge and discharge of 75kw (100hp) and 10kw (13.5hp).

Poor for large energy storage, great for large bursts of acceleration and braking, in a lightweight and compact package.

These cells are more than 10 year old tech. I believe modern cell specs have at least doubled, in some metrics.