Haven't we been using electric motors and smaller turbos to get around lag? I drove a 3 cylinder MHEV EcoBoost that seemed to use the electric motor(s?) quite well. It seems like a good idea in theory, though I can understand the negatives of electrifying the powertrain. Definitely an interesting topic.
I remember hearing about the days of the early 911 Turbos (if my memory's correct) where you'd get a bunch of boost all at once... We've definitely come a long way!
That's a different design; Audi uses a separate electric supercharger to fill in boost while waiting for its conventional turbochargers to spool up. Porsche is using a motor/generator built in to a turbocharger to spool it faster, and to recover energy at maximum boost.
I was thinking of that when I wrote the comment! I've heard of electric turbochargers, but I'm not sure how good they are under real-life conditions. Directly using heat energy from the exhaust (as opposed to introducing electric conversion losses) seems wiser to me. Part of me has always liked making use of what would otherwise be wasted to entropy.
In theory (though not a mechanic, just have an interest in this), the best middle-ground would be to retain the same design but add a motor to the turbocharger shaft which would mainly be reserved for spool ups -- is that what they're doing?
What you've described is exactly how the F1 MGU-H works (as I posted below). F1 is getting rid of it next year because it costs too much for an F1 team which should tell you a little bit about the complexity involved.
GM is doing nothing of the sort, it's just an ECU map. Guessing here, but if driver presses on the gas quickly (throttle accel > some set value), juice the engine map to create extra exhaust pressure to spool up the turbo impeller. It's all software.
Well, from what I understand, the car I drove did. I believe the motor was hooked up to engine's output shaft in some way, so they could work together to generate torque. The gearing seemed very low for the displacement (even had a 6th gear!), so it would suggest they were making good use of the electric powertrain.
I don't miss that either (in fact, I know the ECU can do a much better job), but I do enjoy engaging with the car, and thus drive a manual transmission. I'm fairly confident I can get better efficiency and control as opposed to the same transmission with a computer changing gears for me.
From what I've heard, it's somewhat of a rarity in the US, but it's very widely used in Europe.
Horses are very fuel inefficient. Sure they burn 100% renewable hay/oats, but they burn a lot of them. Worse they burn them even at idle so those who don't use their horse constantly still pay for the fuel.
I remember hearing about the days of the early 911 Turbos (if my memory's correct) where you'd get a bunch of boost all at once... We've definitely come a long way!