GM has many chief engineers.
Dr. Mohsen Shabana is chief engineer for the GM Sequel (fuel cell car) project (
General Motors chief engineer: hydrogen as transportation fuel will shape the rest of the century).
You can read more about GM's fuel cells and advanced technology vehicles
here.
Finally,
AutoblogGreen has some interesting articles about technologies under development, including a 6-stroke cycle "steam" engine.
There are a lot of innovative projects going on around the world in the areas of energy efficiency, alternative fuels and CO2 reduction.