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, 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.”


· · 2 years ago

Sounds like a right direction to go. I just hope the new more efficient engine is less noisy, and can supply more power to climb mountains on longer uphill trips.
It will be even better if it can run on biodiesel, or flex-fuel like some of other GM conventional vehicles. Meanwhile I will keep driving my Volt.

· · 2 years ago

I wish they would also go back to the original styling.

· · 2 years ago

If they make it a true serial hybrid, the engine needs to be just powerful enough at it's peak efficiency RPM to *slightly exceed* the average load on the drivetrain. Then, they could still use the engine (on its own without the electric motor) to push the car on flat ground at highway speeds. I think a 600-800cc 2-3 cylinder engine would be fine for this.

They can also improve the aero drag and lower the weight - in addition to the large savings from the small engine and much simplified transmission, smaller fuel tank, and smaller cooling system. They can use an active damper in the grill to close it down when the engine is not in use, and this will lower drag by as much as 10% when running in pure electric mode; and it would speed up warm up time for the engine, too.


· · 2 years ago

The original styling was farcical - the drag is better driving it backward... It required highly complex curved glass for the side windows; and they could not be rolled down!

Talk about the styling-tail wagging the dog-car!


· · 2 years ago

This is good news, if this turns out to be true. Moving to a larger ICE for 2014 seemed to be a goofy idea.

Having borrowed a 2011 Volt from the local Chevy dealer for a couple weeks and generally finding the car to be excellent, my thoughts are for GM to install the Voltec drive train in a couple of different vehicles. One might be more of a sports car (small, lighter, 2-door) format and, while the current Volt 4-door is fine for a driver with three passengers with limited luggage, I know I'm not the only one to think that Voltec-powered minivan would be most welcome.

Also, since VW is now showing off the limited production ultra-aerodynamic/efficient 2-seat XL1, why can't GM do something along these lines?

· · 2 years ago

@ Callajero

Forget diesel and biodiesel, this is the worst fuel for the environment.
Back here in Europe we're choking on the poisonous, cancer inducing dust that it produces.
You're much better off with gasoline, that can be modified to run on Ethanol or even better, natural gas.
Far less harmful fuels (when burned)

· · 2 years ago

The attractive idea regarding biodiesel, Teq, is that it can essentially run in millions of existing diesel engines with little or no mechanical modification. During the "Modern EV Dark Ages" (roughly 2003, when EV1s leases were expiring and those cars were being crushed, to about 2009, when it appeared that EVs like the Nissan Leaf were really on their way to the commercial market,) a lot of us were paying very close attention to biodiesel. It's not perfect (what is?) but it's pretty good.

First off, it's mostly plant oil of some sort that's cooked with methyl alcohol and lye. So, while not completely fossil fuel free (the methyl being mostly derived from coal, until viable bioethanol is really here) it's basically a non-petroleum product.

When burned, there is far less harmful particulates than when burning petrodiesel. It actually cleans and lubricates the interior components of the engine, which is exactly the opposite of the corrosive effect that petrodiesel is known for. I keep a gallon jug around the house and use it for cleaning rust off of old tools and lubing my bicycle chain. It's even a very good wood polish for non-finished pieces like teak, ebony and rosewood!

The down side is that most current biodiesel involves food stock plants (corn, soy, etc.,) so you've got the same "food for fuel" conundrum as you would with corn ethanol here in the US. Some biodiesel in Europe is produced with palm oil from the South Pacific, which means old growth in rain forest regions is often cleared to produce it. That's clearly the wrong way to go about it.

But next generation biodiesel is already being produced with algae. The amount of land involved is miniscule when compared to growing food stock and production facilities can be located in places that wouldn't accommodate agricultural production and can also utilized non-potable waste or brackish water.

So . . . when we're talking about small range extender engines that would mate with a battery motor for a long range PHEV, a tiny diesel that is sipping minute quantities of a liquid fuel like algae-based biodiesel sounds pretty appealing.

· · 2 years ago

Granted, biodiesel is much better then the regular one, tho I still can't shake of the horrible feeling of diesel when I see a cloud of black smoke behind these cars nearly every day iIdrive. (not to mention trucks and buses)
Bit of a persnomal thing I guess :) I also can't stand the stench.
My car leaves around about 100g of co2 per km and neraly no NOx gasses and particles.

Still i get the energy density of diesel is very tempting to use in range extenders.

Im yet to see a natural gas range extender powered by the gas scraped out of atmosphere using renewable energy (kind of a substitute for baterries, since the gas is esentialy made by using electricity)

· · 2 years ago

"They can use an active damper in the grill to close it down when the engine is not in use,"

Volt already has a "fake grill"...

Volt can improve efficiency by going the "dumb" hybrid route. But I would certainly hope NOT. Putting a pair of skinny tires on them will help a lot too but it will make Volt worse to drive.

The last thing we need is another "incompetent" plugin...

· · 2 years ago

I had heard through the grape vine that, with all of GM Europe's labor troubles due to overcapacity, they changed their mind to use the Austrian Engine to give those people something to do and quiet them down.

· · 2 years ago

Isn’t there some room for engine flexibility? Most conventional cars give the choice between at least 3 engines. There is no fundamental reason why the Volt could not offer the same.
The same is true for the battery pack. When we look at it closer we see clearly that it is the middle section of the pack that prevents a full size back seat for 3 persons. It must be possible to propose a pack without that middle section. It would imply less energy in the pack but perhaps that could be exactly compensated by switching in advance to higher efficiency cells in those particular packs.

· · 2 years ago

Neil's comments regarding "the drag is better driving it backward" jogged my memory this morning and took me back to the 1959 Chevrolet Impala, a styling atrocity that had batwing tailfins so large it was alleged that it would lift the rear end off the ground at high speeds
(that urban legend has been debunk, but it doesn't take anything away from the timeless excess of the venerable '59.)

But it doesn't stop there. As a clever joke, some 10 years later, a group ambitious high school shop class students took a '59 and placed the body on the frame backwards and drove the car around "tail first" for some time. I remember reading about it in one of the car mags back in the early '70s, but I couldn't tell you which one. Thankfully, someone has preserved the story on a witty web page . . .

We now return you to the sober discussion of electric cars with state-of-the-art batteries and hyper-efficient range extenders in sleek (at least sleeker than a backwards '59 Chevy's) clothing.

· · 2 years ago

@Neil - it's fun to get excited about really small engines, but when sizing it, GM will have to consider long hill climbs with 4 people on board. I've done some long hill climbs in the Volt and the engine was working overtime to keep up with the rate of traffic, even when I engaged mountain mode in advance. I'm sure there is plenty of room to optimize the Volt's range extender, but just to say that the optimization will be limited due to the extremes they have to design for.

· · 2 years ago

The battery can be used as a buffer - if the genset is started when the battery gets down to say to 30% charge, and the genset can charge it at a rate higher than the average consumption rate, then it wouldn't get behind.

A 30kW genset could recharge the Volt battery in about half an hour, even while driving. It then can be shut down, and the cooling intake grill can be closed up, and the car can go along in EV mode again, until it gets down to that 30% level.


· · 2 years ago

Yes, I agree that the battery acts as a buffer in a system like this. My point is just that when you have a very long hill, your buffer won't necessarily last all the way to the top, especially if you were already in charge sustaining mode by the time that you started the climb. The engine needs to be sized to provide enough power to climb this hill without any assistance from energy stored in the battery because the automaker can't guarantee that the battery will always have energy to contribute. I don't remember exactly what kind of hill climbing performance metrics automakers are held to, but I'm certain 30kW would not cut it in a vehicle the size of the Volt.

· · 2 years ago


Apparently GM DID do sufficient hill climbing with the Volt prototype to allocate up to 30% of the battery to drain, along with the engine, for spirited driving in hill country. They certainly didn't want any early reviews saying "This Car is a Dog".

Those of us on here campagning for a smaller engine, either as an option (or if that's unreasonable due to the volt's relatively low production numbers), then a very small engine for everyone and use 100% of the battery capacity for hill climbing, in addition to whatever engine power there is. Right now, there is a warning to switch to mountain mode several minutes before approaching one. Assumedly, this would have to increase to 25 minutes or some such thing with a very small engine. Since almost all vehicles have Navigation systems, this could be an additional reminder to the driver to "Switch it to Mountain Mode".

The Volt is a pretty good try just as it is, and I'm probably its biggest critic. I'd give it a Fair to Good, but then I'm a Hard Marker. At least 95% of other owners rate it Excellent, and its the most loved car ever for 2 years in a row ever since manufacturers bothered to start caring about public acceptance of their products.

· · 2 years ago

@Benjamin Nead

Speaking of Red 1959 Biscayne's, my parents went out and bought a brand new Red one in late 1958 (as a very very young child its the very first car I remember), with the only option being a push-buttonless AM Hybrid Delco Radio,(the pushbuttons added another $25 and my dad wouldn't spring for it); it was the latest thing, two transistors I think, one Audio frequency preamp, and the other the Class "A" power output. The radio had the most current draw at no volume (a bit less than 1 1/3 amps) (the way class A works). I think it had about 3 watts audio output to a decently sized center mounted dashboard speaker. It also had in it the very latest 12 volt tubes, running the signal section (I believe 4 tubes) of the radio on only 12 volts rather than 250-300 as the previous "Vibrator Supply" radios had. So, it was now possible engine off to listen to the radio for hours and hours and hours without worrying whether the car would start. (Who knew that 1950's and earlier bugaboo would reappear in the 2011 volt - I ran the battery dead in 3 hours by listening to the car radio in my garage the first week I owned the car). You could always know you were hearing a "Delco HyBrid", since the speaker would 'thump' immediately on turn on, but no music until 9 seconds later after the small signal tubes warmed up.

The '59 Biscayne had other attractive features, most notably "Rocket Ship" styled speedometer and Fuel/warning light housings, in keeping with what some have called, the "Populuxe Era" , think George Jetson.

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