Navistar International, EcoMotors developing new engine architecture

Navistar International Corporation is developing new engine architecture with EcoMotors International that will result in a powerplant that is far lighter than current models, uses 50% fewer parts, and produces much lower exhaust emissions, all with the use of conventional components, materials, and manufacturing processes.

Navistar is working with EcoMotors of Allen Park MI to commercialize what the two companies call a “breakthrough” engine architecture design for the truck market via a turbocharged diesel model.

Using EcoMotors' “opposed-piston, opposed-cylinder” architecture, or “opoc” for short, Navistar expects to produce lightweight engines that further reduce emissions within the next several years.

EcoMotors, founded in 2008, said its engine design can be used in many forms, including cars, light trucks, commercial vehicles, aerospace, marine, agriculture, auxiliary power units, and generators — basically in any equipment currently powered by conventional gas or diesel models.

The two primary investors in EcoMotors — Khosla Ventures and Microsoft founder Bill Gates — see in this technology a chance to reduce harmful exhaust pollutants without sacrificing engine power.

Don Runkle, EcoMotors's CEO, said the opoc engine comprises two opposing cylinders per module, with a crankshaft between them, with each cylinder containing two pistons moving in opposite directions. This design configuration eliminates the cylinder-head and valve-train components of conventional engines, offering a more efficient, compact, and simple core engine structure.

The result is an engine family that is lighter, more efficient, and economical, with lower exhaust emissions that can run on almost any fuel: gasoline, diesel, natural gas, and ethanol.

He also said the key metric for future engine designs is “power density,” for as greater power density is achieved, engines can become smaller, weigh less, cost less to build, and generate lower amounts of internal friction.

EcoMotors' design is but one of several new architectures being touted as a way to simultaneously boost fuel efficiency while lowering emissions for a range of vehicles.

For several years, the West Springfield MA-based Scuderi Group has been working to commercialize its “split-cycle” engine design, which divides the four strokes of a conventional combustion cycle over two paired cylinders: one intake/compression cylinder and one power/exhaust cylinder.

By firing after top-dead center, this engine architecture reportedly produces more efficient, cleaner combustion with one cylinder and compressed air in the other, while requiring just one crankshaft revolution as opposed to the two required in current engine model - all while purportedly producing more torque than gasoline and diesel engines, the firm said.

The firm contracted with the Southwest Research Institute (SwRI) to conduct computer model tests and vehicle simulations using a 1-liter gasoline-fueled Scuderi prototype in a 2004 Chevrolet Cavalier and found its design consumed 25% less fuel than current platforms for that size of vehicle.

The company also expects its naturally-aspirated air-hybrid split-cycle engine design should consume 30% to 36% less fuel under similar drive conditions.

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