Ford Motor Co. says the next-generation of its direct-injected turbocharged EcoBoost engines will feature cooled exhaust gas circulation, a technology typically found on diesels.

The addition of EGR is expected to boost fuel economy in EcoBoost engines 5%, Ford says, noting the technology also reduces the tendency for an engine to knock as it lowers the combustion temperature.

Other technologies being studied for the engines include “more advanced forms of turbocharging,” Ford says, without revealing further details.

The auto maker does not disclose when the next-generation EcoBoost engines will debut, but sources tell Ward’s to expect them by 2015.

Ford’s current-generation EcoBoost mills, which currently come in displacements of 2.0L and 3.5L, already share many attributes of diesels, including a high-pressure, direct-injection system, pistons with optimized bowls to improve combustion efficiency and oil-cooled pistons that reduce in-cylinder temperatures.

But unlike diesels, EcoBoost components are specially developed to handle the higher temperatures found in a gasoline engine, says Brett Hinds, Ford's advance engineering design and development manager.

“Many parts had to be upgraded to special metals and alloys that hold up to that environment,” he says in a statement. “Our exhaust manifolds, for example, are made of stainless steel, and the turbochargers are made from high-temperature cast-iron alloy.”

EcoBoost and diesel engines also share higher pressures in the fuel system and higher compression ratios.

For example, a regular port-injected engine’s fuel pressure is about 65 psi (4.5 bar), while the pressure at which the fuel is delivered through an EcoBoost engine’s injectors can be as high as 2,250 psi (155 bar), Ford says.