Transonic Combustion's New Ultra-Efficient Engine Gets Up to 98 MPG

A California-based company called Transonic Combustion has recently developed a very efficient fuel-injection system that can put on hold the production of expensive gas-electric hybrids. The technology increases mileage from 48 (range of a Toyota Prius) to 64 miles per gallon in highway driving.

In order to get a fast and clean combustion, the gasoline is preheated and pressurized before it is injected into the combustion chamber. But in order to also get a lower fuel consumption, the gasoline is partially oxidized (“activated”) by a prior treatment with a catalyst.

Nowadays, the people’s priority has changed. They need cars in order to do their daily work but they need them to be very efficient: reduced purchase costs, good mileage and reliable. The purchase cost of vehicles and their reliability have been complementary during the last few years: while reliability increased, purchase costs decreased. But the fuel consumption had been reduced only rarely because of investment costs in new technologies. Some car manufacturers included turbo chargers in smaller engines, some improved valve timing and direct injection, in which fuel is injected directly into the combustion chamber rather than into an adjacent port.

Transonic may have found the technology we have been waiting a long time. The company promises a fuel usage reduced with about 20% while the costs of the system are almost the same with an actual high-end fuel injection system. Transonic’s injection system works similar to diesel engines: it uses supercritical fluids and requires no spark to ignite the fuel.

The supercritical fluid is mixed immediately with air when it’s injected into the cylinder. When the fuel gets to the piston, heat and pressure will cause the combustion which is fast and uniform. Ignition will only start when the piston gets in the optimal position, thus reducing the gasoline waste and increasing the energy conversion into mechanical work as much as possible.

The new system is also able to reduce the “throttling losses”. In normal engines, the throttle is partially closed during cruising, making the engine work harder. Transonic’s proposes to operate with the throttle open, creating a lean mixture in the combustion chamber with lots of air, but just a little gasoline. With a cruising speed of 50 miles per hour, the test car was able to get 98 miles per gallon.

Transonic tested the new system with their own built engine and now plan to make the same tests with three car manufacturers. Is is investigated as well what the impact of high pressures and temperatures over the life time of the engine is. The company hopes to build its first factory by 2013 and to introduce the technology in serial production by 2014.