Nostrum says it is in the final stages of securing a contract with a fleet operator for a small-scale trial of the injectors, declining to identify the company.

Currently, Nostrum is producing its injectors only by the dozens to meet developmental needs. It is seeking to acquire an injector manufacturer in the U.S. to begin higher-volume production of the devices.

The injectors are merely the initial step toward Nostrum developing a revolutionary engine capable of achieving a fuel efficiency of at least 100 mpg. A key feature of the Nostrum engine will be an internal water-steam cooling system that would reduce the size of the radiator and ultimately the catalytic converter.

“You don't have to clean up dirt that's not produced,” Coventry says.

In the experimental engine, water is injected into the cylinder and heated under compression until it turns to steam. Water expands 1,250 times when it is vaporized, and that expansion provides added power to drive the piston.

Until Nostrum's current developmental work, it was widely believed that water evaporates and disappears because of the heat produced in the cylinder. Mulye’s breakthrough came in challenging that notion.

“My calculation back in 1987 was that very little water will evaporate,” he says.

At present, the Nostrum engine injects a variable amount of water into the cylinder, depending on the amount of fuel being burned, and the water is recovered and used again as part of a closed-loop system.

A separate water tank, about the size of a windshield washer-fluid bottle, is required to supply the water and it must be heated to prevent freezing in cold weather. The tank looks like the container that holds urea used to treat the emissions in many of today's diesel engines.

Conventional engines transmit less than 15% of the energy they produce to a vehicle's wheels and about 20% to the driveshaft (as high as 30% at very high load).

“Most of the time a car is working at 10% of its power,” Coventry says. “We think we can raise that efficiency to as high as 60% to the shaft and 45% to the wheels.”

Nostrum is targeting at least 100 mpg with both conventional IC diesel and gasoline engines. Fuel efficiency could go higher by adding a stop/start system and other technologies or by switching to a hybrid powertrain.

This fuel efficiency can be achieved without diminishing horsepower, Coventry says.

An added benefit is the clean exhaust produced by the Nostrum engine.

“It produces practically zero NOx (oxides of nitrogen),” Coventry claims. “You don't need highly loaded catalytic converters or SCR (selective catalytic reduction) systems.”

Reducing the amount of precious metals in the converters can reduce costs up to $300 per vehicle, he says. SCR systems can cost as much as $20,000 for large trucks.

Nostrum says it has begun a joint development project with one of the Detroit Three, but Mulye and Coventry decline to reveal the automaker’s identity. They forecast it will take at least a decade before they can bring a complete Nostrum engine to market.

“But we can see versions of this engine before 2020,” Coventry says.