It will be interesting to see what happens with diesels.
The basic problem is that they don't play well with Cats. But surely modern turbo-diesels, especially those with a throttle and stop-start, can be tuned to work better?
I guess the big issue would be the drop in power if they wind back the the over-fuelling?
The very interesting thing will be, if we move back towards more petrol engines, whether LPG starts to make a comeback.
Something I have never understood is why the Hybrid push started with small cars that were economical anyway, where the added weight & bulk of the hybrid system and battery was an imposition, and the additional cost prohibitive. Why don't we have Hybrid Buses and Trucks?
To get back to the
OP's question:
IF you're talking about an Engine that you really WANT. Then, for me:
NO V6's. Goddamn awful engines with no redeeming qualities. (Other than being compact and CHEAP.)
NO Turbos. I drive a turbo, and its an easy way to get more power, but they don't improve engines, and I don't really like them.
NO naff names like ecoboost, ecotech, etc. If you have to name your engine, make it something cool, like the "Grunter."
I still like the I6. Particularly with twin variable cams. Something with a lightweight alloy block, around 3.6L
For allround niceness and symmetry, its still hard to go past a V8. All alloy, around 4.0L
It would be nice to see what modern design and manufacturing could do with a single cam, perhaps with some kind of variable time and lift.
The exception I would make to forced induction would be a electric super-charger as part of a Hybrid Miller-Cycle engine.
As a left-field option, I would love to see what modern design, materials, and engine management, could do with a hybrid ****el.