Isn't that exactly what hybrid cars (e.g. Prius) are? Extremely efficient gas engine for highway cruising, but insufficient for acceleration, which is aided by electric motors?
Both the engine and motors are used at all speeds. Particularly during highway acceleration the entire assembly rotates in the same direction.
No, quite a few other hybrids are just an electrical motor tacked on to an existing ICE drivetrain, and they are actually more complicated than a regular ICE car, with horrible reliability and repair cost. And other non-hybrid minivans are either seriously underpowered, or require a seriously big engine that eats fuel.
The complaints that people have against hybrids and minivans are valid, if they're not talking about Toyota hybrids or this specific Toyota minivan.
> Isn't that exactly what hybrid cars (e.g. Prius) are? Extremely efficient gas engine for highway cruising, but insufficient for acceleration, which is aided by electric motors?
Well, it kinda depends. Where Hybrids get the biggest MPG boost is in city driving. The stop and go traffic lets you use Regen braking and go quite some time without the engine kicking back on while still moving forward.
I still don't understand Honda's system enough to speak well on it, but I can speak to THS because it seems to be the cheapest to do and is most proven on the road.
The general parameters for a THS type system on a Toyota Prius or Rav4, or a Ford Maverick/Fusion/Escape is a 2.0L or 2.5L (at least in modern US examples) engine paired to a simple planetary gearset containing a power split device. It is a single speed (At least in the cheap configurations, however that simplicity is possibly close enough to be viable for air usage vs a reduction gear.) That's part of why they tend to have fairly large engines, the valve timing magic gives them at least a bit more HP to not be too bad on the highway.
> but insufficient for acceleration
Going back to the modern cases, the engine is typically sized large enough to give some acceleration even on the highway. Not always great but usually enough.
At least as far as the non-plug-in hybrids, the 0-35MPH can be surprisingly peppy.
The bigger magic (again, at least as far as THS) is it makes it easy to just run the engine at the 'most optimal RPM' for certain tasks, excess energy gets piped to the battery or back out through the system, this does also help reliability tho, because you can then design the reliability of the engine around certain RPM ranges...
Most hybrids are actually parallel or series-parallel. Series hybrids are comparatively rare because the traction motor has to be sized for the full operational range of the vehicle. Their primary advantages are mechanical simplicity and packaging; even though the power electronics and motors are bigger, the lack of mechanical coupling means you can put them wherever is convenient.
There's a video linked elsewhere in this thread that explains how the toyota system works, it's worth watching as it clears up several common misconceptions about the system.
... and instead drive one of the motors, generating electricity to power the other motor to push the car forward.
I feel like that video you're mentioning did a poor job if it didn't describe one of the more important and clever aspects of the Prius's design.