Nissan, working with Renault, has developed two new fuel-efficient in-line 4-cylinder gasoline engines and a new continuously variable transmission (CVT). The automakers will implement the new hardware on various small passenger cars beginning this autumn.

The new 1.5-liter and the 2.0-liter units both incorporate new shared technologies designed to provide improved fuel economy combined with improved acceleration under the most common daily driving conditions.

• Strengthening the gas flow in the combustion chamber shortens the combustion period and improves thermal efficiency.

• New manufacturing technologies reduce friction, including the use of a new machining method for the cylinder bores and the application of a mirror-like finish to the crankshaft and cam bearing surfaces.

• The load imposed on the engine to drive the air conditioner and other auxiliary units has been reduced by enhancing their efficiency and improving the control program.

The new Nissan CVT enhances the characteristic benefits of this type of transmission, including improved fuel economy, smooth power delivery without any shift shock and acceleration performance. In particular, Nissan improved shift response by tuning the hydraulic and electronic controls. This improved shift response, combined with a wider gear ratio range, contributes significantly to fuel economy under ordinary driving conditions.

No hard numbers on the actual improvement in fuel economy when the engines and the CVT are combined in a vehicle.