Most of the automotive world is in a race to develop the most efficient and lowest cost hybrid propulsion system. In this rush to combine electric and gasoline engine technology other great technologies tend to get overlooked.

Scotland-based Artemis Intelligent Power has unveiled a new hydraulic hybrid powertrain for vehicles based on its Digital Displacement (DD) technology, a core innovation the company has been developing for nearly 15 years.

In confirmed third-party tests, the U.K. Energy Saving Trust, a grant supplier for the project, says Artemis’ prototype BMW 530i hydraulic series hybrid, outfitted with HEDDAT (High Efficiency Digital Displacement Automotive Transmission) technology performed with double the MPG in city tests (a start and stop environment) of the same car with a manual transmission.

Artemis and the Energy Saving Trust say the performance of the BMW prototype, including highway driving, revealed 30 per cent lower CO2 emissions before the company fitted the hydraulic transmission.

Dr. Niall Caldwell, a senior engineer with the company since its inception in 1994, said it's difficult to compare the performance of a Artemis hydraulic transmission to the technology of an electric hybrid.

“Whenever there’s a lot of starting and stopping, that’s where we’ll beat electric hybrids,” said Caldwell. “We can store energy at a faster rate.”

The company claims its Digital Displacement technology replaces the port and swash plates in conventional hydraulic machines with computer-controlled high speed solenoid valves and because of this the DD technology will be less expensive than a traditional hybrid when it goes into mass-manufactured.

Artemis thinks that this new hydraulic transmission technology should be more durable, lighter and cheaper than electric hybrids, and most vehicles will likely see substantially better fuel savings.

“We have the advantage on aggressive duty cycles, and that’s where the Prius system cannot capture and return the energy at high powers,” said Caldwell. “There’s an intrinsic technological advantage when you’re driving a vehicle hard. That’s where hydraulic hybrids have a huge advantage.”

Artemis says it already has licensing contracts with Bosch Rexroth, a Bosch company, and Sauer-Danfoss APS, both of which are international manufacturers.