General Motors could soon swap the electric Volt's range-extending four-cylinder petrol engine for a new three-cylinder mill, according to reports out of the US this week.
According to US website Edmunds, the project - which is still to be decided on - would see the existing 1.4 unit replaced by a new 1.0 or 1.2 litre engine currently in development with GM's partners in China.
If approved, the new engine could make its way into the Volt by late 2015, timed to coincide with a styling and technology update.
In 2011, General Motors confirmed plans to develop a number of new three- and four-cylinder engines, ranging in capacity from 1.0 to 1.5 litre.
The carmaker has yet to detail the new powerplants, or which models and markets they are destined for.
"We're not ready to talk about any applications," a GM spokesperson told Edmunds this week. "We don't have one right now for the U.S. and I wouldn't be able to say that we have one planned for the U.S. at this point either. We have not announced any of that."
It is known however that the project forms part of GM's plan to reduce fuel consumption through lighter technologies.
"A good rule of thumb is that a 10 percent reduction in curb weight will reduce fuel consumption by about 6.5 percent," GM CEO Dan Akerson said. "Our target is to reduce weight by up to 15 percent."
Rival carmaker BMW is also working on a range-extended version of its own i3 electric vehicle, confirming last year that a two-cylinder petrol engine will feature.
In its current guise, the Volt is driven primarily by a 111kW/368Nm front-mounted electric motor, paired with a small 1.4 litre petrol engine, the latter powering a generator that keeps the electric motor's lithium-ion battery pack charged.
It was a 'parts-bin' choice by GM at the time, to keep development and production costs down while battling through the worst of the GFC and while under Chapter 11 bankruptcy.
Most contend, and GM would clearly agree, that 1.4 litres was overkill for a motor whose main function is to drive a generator to keep the batteries charged.