Citing an anonymous source, on Friday it was reported that GM is considering a proposal to shrink its present range-extending generator in the Chevy Volt and Cadillac ELR to a 1.0-liter or 1.2-liter three cylinder.

Specifications for the engine were not given and the story by Edmunds was neither confirmed nor denied by a GM representative the publication consulted.

The story as given is that the engine – developed with GM and its Chinese partners – is being proposed and use of a lighter design would be in keeping with GM’s general plans announced to decrease curb weight and decrease fuel consumption in Gvarious models over the next several years.

If the plan is accepted, the 2015 Volt would see the three-cylinder generator as part of its major refresh, referred to generally as the much-anticipated “Generation 2” Volt.

The 2014 Cadillac ELR’s powertrain, based largely on the Volt’s powertrain, has not even been launched yet, and the report for its new engine said it would see the three-cylinder specified the year following the Volt’s receiving it.

Presently the Volt makes use of an 84-horsepower 1.4-liter four-cylinder plus electric power rated at 149 horsepower (111 kw).

Last year another such rumor said to be from a reputable source said the Volt and ELR would get a 2.0-liter, but the specs on the ELR proved that false, as it uses the same 1.4-liter the Volt does.

This does not mean the new three-cylinder story is false, and GM may indeed be evaluating the proposal. If it meets its criteria, it is possible it will make its way to production, but at this point, it’s a case of wait and see.