Ford’s 3-Cylinder Engine: Efficiency Lies in the Details

More than a dozen efficiency features highlight Ford Motor Co.'s new 1.0-liter, three-cylinder gasoline engine, Automotive Engineering International note online.

First iterations of the 214-lb turbocharged powerplant for the Focus small sedan and B-Max MPV produce 99 hp and 123 hp. Ford says the units will deliver performance comparable to the 1.6-liter four-cylinder engine they replace but with 20% better fuel economy. The engine is being produced at Ford's big engine plant in Cologne, Germany.

Ford says the three-pot engine will require a special low-friction motor oil developed with BP. Other friction-cutting features include low-tension piston rings, special crankshaft seals, a variable displacement oil pump and a timing belt that is immersed in oil. Separate liquid cooling circuits for the block and cylinder head help accelerate engine warm-up, thus reducing the drop in efficiency during cold starts by roughly one-third compared with a conventional engine.

Thomas Zenner, who supervises Ford's three-cylinder engine development, tells AEI the new engine offers the highest power density of any Ford powerplant ever built. One reason: a custom turbocharger developed by Continental AG. The device's turbine measures only 1.5 inches in diameter and spins at speeds as high as 248,000 rpm.

The turbocharger can withstand operating temperatures of more than 1,000 C without the need for rich fuel mixture cooling. The system's vacuum-assisted wastegate provides boost control and helps reduce pumping losses, thus contributing a few percentage points of improved fuel economy, according to Ford.

The tiny turbo is fitted to an exhaust manifold integrated into the cylinder head casting. Zenner says the configuration is about 2.2 lbs lighter than a conventional manifold system.

Developers opted for a cast iron rather than aluminum block, which they say reduces friction and aids engine warm-up. Ford tells AEI the three-cylinder engine costs more to produce than a comparable four-cylinder gasoline engine but not as much as a diesel, at least at initial production levels.