[BillR]

The new HCCI (Homogeneous Charge Compression Ignition) engine will debut in an Opel. GM claims up to a 15% better efficiency.

http://www.motorauthority.com/cars/general-motors/opel-insignia-to-debut-hcci-sparkless-technology/

The ICE for the Volt might make good use of this technology, especially considering that it will probably operate in a narrow band of speed and power.

 

[Jason M. Hendler]

Here are my votes for the ultime RE:

Rotopower Rotary Engine

- a combination super / turbo charged rotary (Wankel) engine that greatly increases efficiency, while reducing emissions to near zero.

Enginair Rotory Air Motor

- a rotary configuration of an air motor for zero emissions.

 

[Glen M]

I want it to have a hydrogen peroxide powered turbine. Just for dramatics.

 

[DaV8or]

This is great technology. Diesel performance without diesel fuel. It would be great for the Volt. I have a feeling that it won't be in Gen 1 Volt though. I get the feeling that to keep costs down and get the Volt out as fast as possible, they're going pretty conventional on the ICE with off the shelf components. I think this is OK since the ICE will hardly ever run for a lot of folks.