A new role for the ICE

Volt's modified Family Zero inline four is along for the ride-until it's needed.

Judged by its individual components, Volt's 1.4-L four-cylinder combustion engine resembles its nearly identical cousin in the Chevrolet Cruze. It has got an aluminum DOHC head with four valves per cylinder. Its hollow-frame iron cylinder block is a thin-wall casting, making it nearly as light as a comparable aluminum block while retaining iron's inherent strength and noise-damping qualities.

Derived from GM's global Family Zero of small-displacement gasoline inline triples and fours, the Volt engine was designed for efficient operation. Its hollow camshafts are manipulated with two-step variable electrohydraulic phasers. Its lubricant is distributed through a variable-displacement flow-control oil pump to reduce parasitics under light load conditions. The thermostat is map-controlled.