Ward’s Says Chevrolet Volt’s Propulsion System Is “Shockingly Good”

SEP 1 2017 BY MARK KANE 40

The second generation Chevrolet Volt is one of the most popular plug-in electric car choices in the U.S. so far this year some 14,000+ have been sold, and total sales are well past 125,000 units since 2011 (including the first generation).

2016 Chevy Volt Cutaway

With 53 miles of all-electric range and the top reliability – both on the powertrain and 18.4 kWh battery, WardsAuto calls the Gen II Chevy Volt’s propulsion system shockingly good.

Chevrolet Volt also won the WardsAuto’s 10 Best Engines award in 2011 (debut of the first generation) and 2017 (debut of second generation).

Gary Witzenburg, once engaged in GM’s EV1 project, talked with the GM Global Vehicle Chief Engineer Barry Walkup about why the Volt II is so special.

First of all, GM successfully integrated the powertrain (1.5L direct-injected Atkinson-cycle I-4 engine, two electric motors and two planetary gearsets and three clutches) into the Chevy Cruze architecture, achieving versatility between the all-electric car (which will be always more efficient, but sometimes doesn’t have enough range) and a conventional hybrid car (which will be more efficient on the very long trips, but not on daily all-electric commutes). Ward finds the Volt combines the advantages of BEVs and HEVs very well.

Here are a couple areas important for the engineers who developed the Volt:

Integration of the powertrain to achieve smooth and quiet transition between the all-electric and engine modes, as well as reliability.

Barry Walkup explained:

“Our goal was to keep the engine quiet,” he says. “We didn’t want clunks or bumps or any indication that it has started. We torque-match the electric motor to the gasoline engine and pre-fill the cylinders with gas during stop/start, which allows the engine to start quickly.

“We coordinate the fuel and air controls and optimize the powertrain mounts to filter out engine vibration, dampen engine noise with acoustical damping and desensitize the car to noise and vibration. We wanted to maintain the electric vehicle perception even when the engine is running.”

“Another challenge was ensuring the drive-unit-mounted integrated power electronics could survive significant powertrain vibration, especially if the engine misfires.”

Battery. The next-generation battery is 18.4 kWh, 20% more energy dense with 10% more power and 30 lb. (14 kg) lighter.

Engine. The engine is 1.5L instead 1.4L so the power and torque increased by 20% and 10% respectively. But even more importantly, it can run at lower rpm, improving fuel efficiency and quietness.

Electric motors. Instead of one big and one medium-size motor, there are  two medium-size motors – and both are able to be motors or generators at any time, instead of a fixed role.

“Another major improvement is the capability to use both motors at any time, as motor or generator, in EV or range-extending mode, which enabled a 60-lb. (27 kg) lighter drive unit. Mounting the power electronics directly atop the drive unit got rid of the Gen I’s big and expensive orange connecting cables and eliminated another 40 lbs. (18 kg). Still more mass reduction came from eliminating one of the Gen I’s two drive-unit oil pumps.

The transmission also is improved significantly. “The Gen I had a big motor and a medium-size motor inside it, while the Gen II has two medium-size motors that enable better torque transitions and less mass. Kind of an electric CVT, it’s now compatible with the Malibu Hybrid and other platforms.””

Optimization of 0-30 mph (48 km/h) acceleration and drivability for city driving.

WardsAuto opinion:

WardsAuto editors agree: “Stunning level of quiet and refined power from 0 rpm and ample power across the range, low, passing and highway cruising,” says Editor (and Gen I Volt owner) Bob Gritzinger.

“Silent as a submarine,” adds Editor Dave Zoia. “Engine transition (from EV to EREV mode) nearly imperceptible.”

source: WardsAuto

Categories: Chevrolet

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40 Comments on "Ward’s Says Chevrolet Volt’s Propulsion System Is “Shockingly Good”"

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I still say a dust up between the Volt Drivetrain, and the Bolt EV Drivetrain, should result in a very Long Range EREV 4 Wheel Drive: SUV, Truck, CUV, or posibly even, Limousine! This combo could also do great things for School Buses!

Yes, this please!

I think if you take the form factor of the BoltEV battery pack and combine it with the remainder of the Voltec drive train, you could create PHEVs with capacities of 20-60kwhrs without impinging on the passenger/cargo areas in any meaningful way. It would be near perfect from a packaging standpoint. And as you point out with such a wide range of battery capacity you could use the system on anything as small as a Cruze or as large as a Traverse. GM please get off your asses and make some of these other vehicles. You brought many into your fold with the Volt you will lose them if you don’t give them larger vehicles to grow into. I know I’m one of them, currently a Volt owner, I want something bigger a small/medium CUV or Colorado sized pickup, if you don’t make it GM I will go to the first company that does.

Yes i agree i been round trips and i want a SUV so my grandkids can go places with us me and my neighbor talk about it for couple of years now We seen a all electric Mercedes SUV But the travel is limited. If chevy comes out first they can leed sales because most people buy and stick to that brand..

It looks like the Bolt drivetrain beat out the Volt drivetrain in August sales, 2107 Bolts sold vs. 1445 Volts.
But the Bolt numbers are rising and the Volt numbers are dropping.

Part of this is an inventory problem with the Volt. There’s none around here to speak of, and consumers have been asking.

The 2018 arrival should help a bit, though the Prime may continue to steal some sales.

Wanna bet?

The BMW system is superior. It gives you a hybrid 1% of the time, only when you need it. But, then 99% of the time the characteristics of the car are an EV.
-EV Performance
-EV Quiet

I assume you mean the i3? It wasn’t clear at first. There are other BMW plug in hybrid vehicles.

If only the i3 Rex had a larger fuel tank.

How in the world is the i3 Rex superior? Most would agree the opposite is true.

In terms of all EV range, the i3 wins. But after that, the car can’t climb a hill to save its life thanks to the woefully under-powered range extender.

To the contrary, the Volt’s drivetrain is properly designed to be full performance all the time.

“But, then 99% of the time the characteristics of the car are an EV.”

Plenty of Volt owners share the same experience if their 99% need are within the 53 miles EV range of the Volt.

Volt’s EV mode is pure EV mode.

You must be confused or mistaken…

I went to lake Tahoe and free charging at casino’s but what amazing was coming down the hill my car and lots of braking i was back on full charge by the time i got to Placerville a hour away!!!

Chevy: Put this into what people are buying (small crossover) and you could sell a whole lot more.


Put it in everything. There’s no reason everything shouldn’t have a plug by now.

Agreed Kdawg, there is not reason the Voltec drive train couldn’t be powering nearly all of GM’s vehicles (All but the largest trucks and SUVs, and even then with a beefed up electric motor it could work their too). Give it a sufficient battery size and it could do the job.

That is why I felt mixing the Bolt Drivetrain in the Rear, with the Volt Drivetrain in Front, with from 40 kWh or more, of the Bolt EV’s 60 kWh Battery, to get 4WD plus more total power!

Ding ding ding!

Only reason I didn’t go for a Volt was the size and cabin space. The battery configuration also did not help in this regard.

Bingo. A reasonably-priced ERECUV would fly off of lots. But it looks like Ford might be beating them to the punch with a PHEV Escape.

To many of us it remains a source of mystery and frustration that GM doesn’t put Voltec into mainstream vehicles (mid-sized sedans and Equinox sized CUVs). I love my 2014 Volt but the form factor (small low to the ground 4 door hatchback) is definitely not mainstream for the US at least.

It is a very good powertrain design, but the decision on where to put it and how many to sell are really senior management decisions that have much more to do with quotas than “greening the planet.” The good news is that GM engineering is showing its ability to compete as the world “goes green.”

The Voltec is used in the Malibu hybrid. I don’t have sales figures for it, but I wouldn’t be surprised if there were more “Volt – Like” vehicles driving around as Malibu’s rather than real Volts.

Except probably not in my area – I couldn’t find a single Malibu Hybrid on my dealer’s lot when I was there last week. – Gasoline is just too cheap right now for people to worry about it. Probably explains why the BOLT ev is selling so poorly in my area also.

Good point…but sadly it is just hybrid, not plug-in hybrid.

“Malibu hybrid. I don’t have sales figures for it,”

Malibu hybrid sales has NEVER beaten the Volt.

And it doesn’t look like it would ever…

GM should put this in more models. Have a plug-in version of every popular car line!

Yup, Ford has their “Energi” trim with a plug, GM should have a “Voltec” trim.

No mention of the gen 1 Volt gas engine needing / using premium gas, and the transition to the gen 2 Volt switching to regular gas. That was a good benefit, along with the larger capacity battery.

I hear you, William, but in the 4+ years I have owned my 2013 Volt, I have only used 39 gallons of gasoline. And 4 gallons of that I got from the dealer.
Paying 20 cents more per gallon of gas doesn’t matter much if you are only using a gallon or two a month.

Agreed, I put gas in my Gen1 so infrequently that I usually don’t even know how much gas costs. Around here premium is 40 cents more expensive than regular, but it’s still an insignificant cost.

Still, it’s nice that the Gen2 runs on regular.

True that. My 350Z ran on premium as well, so I was used to pumping premium when I hit the gas station. Sold the Z and haven’t been to a gas station in months.

Say what you want about GM’s management-level decisions and crappy dealers, but their engineering is world-class. The Gen1 Volt was one of the best engineered vehicles every made by anyone. The Gen2, now that they’ve gotten through a few early issues, also seems to be excellent.

Hopefully Consumer Reports will realize that the number of 2016s shipped didn’t warrant doing a review, never mind bashing the car.

(⌐■_■) Trollnonymous

“Shockingly Good”

But only for a small compact car.

Obviously not scalable otherwise it would’ve been put in a larger car (malibu or impala), suv’s or even a pickup.

How long has it been out and still only stuck with the Volt and lame Caddy model?

It’s scalable…they just don’t want to take away those fat profits from the ICE SUVs.

“they just don’t want to take away those fat profits from the ICE SUVs.”

If majority of their Volt sales are conquest sales, then why would SUV PHEV be risking their profits on ICE versions?

“…Obviously not scalable otherwise it would’ve been put in a larger car (malibu or impala)…”

You should probably google the Malibu hybrid.

The biggest problem with the Volt drivetrain is that it is only available in the Volt.


Volt is such of a great and complete car. The dropping sales is surprising but then again last month when i try to lease one the dealers i visited had very few on hand and they were not negotiating anything. They did have lots of Bolt sitting and collecting dust. The Prime probably has something to do with the dropping sales too which is very sad since the Prime has a pathetic ev range. One thing my wife and i did not like about the Volt was the space in the cabin which seemed restricted….great looking car!

Why no Voltec CUV/SUV? Answer: gross margin. The Voltec drivetrain is more expensive than ICE which would reduce profits. Only when a major competitor introduces a PHEV of a popular CUV/SUV will GM respond.

Well I don’t know what to make of this article. It purports to be about the Volt, but the engineer is clearly speaking of something else in some of the quotes.

For instance, it makes absolutely zero sense to torque match the engine to that of the motor in a Volt, because the engine doesn’t drive the wheels! It’s a series hybrid and the engines job is to drive a generator to charge the battery. End of story. There are no planetary gears, and there is no point having stop/start systems since you charge just as well standing still as you do on the go and the intervals (on or off) are long.

If this is the quality level InsideEVs is shooting for I’m not going to believe a word I read here anymore. Seriously, it’s not acceptable.

You should apply quality to your own comment.
The Volt drivetrain does use its ICE directly to turn the wheel in some condition and it does by engaging a number of clutches and moving or not around its two planetery gear set.
Your wrong on all it seems.