By Katie Fehrenbacher from Gigaom

The internal combustion is officially still alive, and delivering efficiency innovation.

While electric cars get a lot of media attention, the reality is that the internal combustion engine is far from dead, particularly for the future car owners in the developing world. A startup called LiquidPiston — which has been around for years and which got its start as a father-son team in a business plan competition at MIT — is in the process of developing a diesel engine which is far more efficient, smaller and quieter than a standard diesel engine.

The engine, called the X2, will be available as a beta prototype for outside testing by the first quarter of 2013. The engine is able to achieve more than 50 percent efficiency under typical operating modes, while typical diesel engines usually achieve less than 20 percent efficiency.

The X2 is a new type of engine architecture, based on a rotary engine. LiquidPiston CEO and President Alexander Shklonik told met in an interview that this new version of the rotary engine is more flexible and can thus be more efficient when optimized in the right way. The engine is smaller, lighter, and cheaper, with ten times fewer parts, than current diesel engines on the market, says Shklonik.

Shklonik told me in a phone interview that the first applications for the engine won’t be the mainstream automotive industry, but will be industries like defense, long haul trucks, plug-in vehicle range extenders, and other more niche markets. LiquidPiston has raised $12.3 million so far, and tells me that it’s looking to raise another $20 million later this year. The company has around 12 employees.

Other startups that have developed more fuel efficient engines include EcoMotors, Pinnacle Engines, and IRIS Engines. More efficient engines will be used in both the next-generation of cars sold in developing countries, and also countries like the U.S. that have new fuel efficiency standards. The Obama administration passed the CAFE standards, which require a fuel efficiency of 54.5 miles per gallon by 2025.