Why A Bigger Engine Makes The 2016 Chevy Volt More Efficient

Undoubtedly one of the biggest news stories of the Detroit Auto Show was the reveal of the 2016 Chevy Volt, which is basically a better vehicle in every way imaginable. But how did GM manage to improve both fuel economy and electric driving range by using a bigger gas generator, rather than a smaller one? I spoke with powertrain engineer Larry Nitz, who explained a few of the many improvements made to the 2016 Volt.

One of the more contentious issues with the 2016 Volt was the choice to use a larger and more powerful 1.5 liter gas generator, the first such application of this new engine. Many (including me) had assumed the 1.0 liter, three-cylinder engine used in GM’s Opel Adam. Instead though, an all-aluminum 1.5 liter four-cylinder that still makes 149 horsepower, but ups the Volt’s MPG to 41 MPG combined, up from about 37. But as Nitz explained, the more powerful motor makes for an all-around better car, beginning with its ability to draw even more energy from the “clean-sheet” 18.4 kWh battery pack. This is a major contributor to the 50 miles of electric driving range 2016 Volt owners can expect, which is about 30% more range than the 38 miles the 2015 Volt is rated at.

The 1.5 liter engine is also better balanced than a three-cylinder could be, and it doesn’t have to work as hard to make as much power. While a smaller, less-powerful motor should be better for fuel economy in theory, it is also a lot louder in the real world, completely negating the benefits of driving an electric car in the first place. Volt owners vastly prefer the silence of the electric motors to the buzz of the outgoing (and iron-block) 1.4 liter gas engine, and the 1.5 liter engine is supposedly much quieter than the engine it replaced. Another major improvement? It can now run on regular 87 octane fuel with no loss of power or efficiency. That’s a big deal.

There’s also the all-new lithium-ion battery pack to thank for efficiency improvements, which now features two packs in series rather than three. There’s also 96 fewer individual cells that help drop about 20 pounds from the T-shaped battery pack. The battery is also positioned lower in the car, improving the center of gravity and allowing GM to install the much-asked-for fifth seat, making the 2016 Volt more family friendly (though I certainly wouldn’t want to sit there).

But the gas generator is only half of the equation of the 2016 Volt, with the other half being an all-new pair of electric motors, one of which uses none of the contentious heavy rare earth metals controlled by China. That motor uses a ferrite multi-barrier magnet, and total rare earth element usage has been reduced from about 7 pounds of material for about 2.5 pounds. Larry and his team were able to improve the acceleration of the Volt by about 20% in the 0 to 30 MPH range to just 2.6 seconds thanks to various motor and gearing improvements, which should make for a much more engaging driving experience. While the 8.4 second 0 to 60 MPH time still doesn’t qualify as “fast”, it is a slight improvement over the outgoing model.

There are however still two important questions that remain unanswered for me. First, what will the 2016 Volt cost? With all these improvements, should we expect the MSRP to go up, or down?

Secondly, will there ever be a sportier version of the Volt that takes advantage of a larger electric motor? Nitz wouldn’t say, but I don’t see the harm in holding out hope for a little more horsepower.

Source: Gas2