Eventually, if we are to move toward non-hydrocarbon energy (nuclear, solar, etc.) automotive transportation is going to have to move toward pure electrical, hydrogen, and "true" hybrids (electric cars with a small fueled generator for long-range cruise and recharge).

Every sale of a hybrid car pays for the large investments in battery development, which will create a market path for affordable electrics.

The hybrids also serve as a marketing tool for the idea of low-emission, high mileage cars.

Incidentally, many of the ideas you describe for improving internal combustion engines are already being heavily researched by car companies, although more could be done. With computerized ignition and injection, some engines in existing cars already "tune" themselves on the fly for maximum efficiency.