Chevy Volt To Get Smaller Engine, As Originally Intended

By · March 18, 2013

Chevy Volt 2007 Concept

The original design of the Volt concept was bad-ass. But better aerodynamics and a quick path to the market resulted in a more sedate design—and the switch from a 1.0-liter, three-cylinder turbocharged engine to a 1.4-liter non-turbo.

General Motors is once again planning to use a three-cylinder engine for its Chevrolet Volt and Cadillac ELR plug-in hybrids. The idea, which re-emerged based on comments from anonymous sources to Edmunds.com, would be to replace the current 1.4-liter four-cylinder engine in the Volt and ELR with either a 1.0- or 1.2-liter three-cylinder engine.

If approved, the three-cylinder engine would first appear in around 2015 or 2016. The design of the Chevy Volt is also expected to be updated around 2015.

This shift to a smaller engine is basically a return to the original concept of the Volt—to rely almost exclusively on an electric motor and a battery pack for propulsion—and to use the smallest, lightest and most efficient gas- or diesel-engine to extend the car’s range. When the Chevy Volt was first introduced as a concept car in 2007, the plug-in hybrid featured a 1.0-liter, three-cylinder turbocharged flex-fuel capable engine. In July 2008 General Motors confirmed that a non-turbocharged, 1.4-liter four-cylinder engine would instead be used as the range extender—a move most observers pegged to cost reductions during tough financial times for the company.

G.M. announced in October 2011 it would create a family of three- and four-cylinder engines, ranging from 1.0- to 1.5-liters. One of these smaller engines would be well suited to the Volt. The production of smaller engines is part of the company’s broader plan to reduce vehicle weight and fuel consumption across its entire lineup.

In June 2012, other rumors surfaced that the 2014 model will use a 2.0-liter turbo engine. At that time, a G.M. source (again anonymous) said that the current four-cylinder engine is “definitely not” going to make it to 2014. But a shift to a bigger thirstier engine made less sense than switching to one of the smaller more efficient engines in development.

Where Were We?

As early as March 2009, nearly two years before the first Volt sales, G.M. was already discussing going back to a smaller gas engine with the Volt. “All we need is 67 horsepower, enough to maintain the batteries’ charge when the car is cruising at highway speed,” said John Bereisa, a G.M. executive and engineer at the time, in an interview with The New York Times. “Since there wasn’t time to design an engine from scratch, we looked for the smallest existing engine capable of supplying 67 horsepower, which turned out to be G.M.’s Family Zero design used in Europe, Asia, Africa and the Middle East.” Bringing the Chevy Volt to market absolutely as quickly as possible was a critical goal of the Volt program.

The needs of an engine for providing primary propulsion to the wheels is very different from what’s needed in an extended-range electric car. “When you map an engine’s power versus r.p.m. versus fuel consumption, the resulting chart looks like the Rocky Mountains,” said Bereisa. “In conventional cars, you’re driving all over that map. But in the Volt, we’re able to keep the engine operating in what I call its happy valley, where it delivers the power that’s required while consuming minimal fuel.”

So, the latest news (possibly rumors) about a smaller Volt engine are less revelation, and more a return to the original concept. But just how small can G.M. go? As Bereisa said nearly four years ago to the day: “We’d select a smaller displacement engine for the future, probably less than 1 liter.”

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