Lightning GT, Other New Electric Vehicles Debut at British Motor Show
GM Dedicates New $400M Global Powertrain Engineering Development Center

Volt to Use 1.4L Naturally Aspirated Engine

GM has selected a 1.4L naturally aspirated engine as the range-extender in the Volt, according to Larry Nitz, Executive Director, Hybrid Powertrain Engineering.

In April GM had said that it had yet to finalize its selection of the combustion engine component of the Volt powertrain, although the engine would be from its Family 0 of European small-displacement engines (1.0-, 1.2- and 1.4-liter). (Earlier post.)

Nitz confirmed the selection of the 1.4-liter engine on the sidelines of the Plug-in 2008 conference in San Jose, California.


stas peterson

A fine and sound both engineering and economic decision.

GM is going to build a new American factory for the new engine family that is more advanced than the Family 0 engines that were originally proposed.

The new engine will power the Cruze (Cobalt replacement), and has all the the attributes of a very, modern, efficient, small I-4. All die cast aluminum block and head, DOHC, 4 valves, VVT, GDI, and a central location of the GDI injector, so as to be prepared to add HCCI to his engine family in a few years.

Building them in America will ease any dollar exchange issues, and help build volume for reduced costs. The valve train lends itself to Atkinson operation. In the future when HCCI is available, that will raise the efficiency to diesel levels, especially when used for the job of running a generator. In that mode, the majority of time will be spent in HCCI mode.


A decision as stupid as stas-peterson's comments.

The volts is going to be waaaay too heavy, as a results the electric range will sucks, the mileage on extended gaz will suck,last but not least the cost will be too high.

1st a 3 cylinder 1 liter or a 2 stroke 2 cylinder would have been much more appropriate.


Remember that once the battery is expended the Volt will run as a serial hybrid on its ITE. So the engine needs to be big enough to provide adequate power for acceleration and hills.


treehugger do u even know what the weight difference is compared to a 1.0 liter vs a 1.4 liter? You make it sound like 50 lbs of extra aluminum weight is the end of the world.

Then again no one sees the retardation in your comments, just because they chose a NA 1.4 liter 4 cylinder over a 3 cylinder 1.0 liter turbo does not render the system as hopeless, go back to your bike treehugger. Your tone of voice makes me sick as it sounds like those who choose personal transportation should be shot.


Don't pay any attention to Treehugger. His comments have continually proven themselves to be absurd. He is just trying to get attention. For what reason, I have no idea.



It is not because I said that the Volt will be too heavy to be efficient that I am agaisnt personnal transportation, I don't see the connection here.

Asides of Stan Peterson (but for fair reasons) and the marketing policy of the "bigs 3" I haven't agressed anybody and that's not my intent to do so.


Dean -- the engine only needs to be big enough to meet the car's average power requirements. When operating in charge-sustaining mode the battery acts as a very big buffer.

25-30hp really ought to be plenty. 1.4L is probably 3x overkill.


lol the guy like split personalities that's for sure.

Turbos = more maintenance, and with a tiny output on three cylinders i highly doubt it'll meet demands at its most efficient rpm.

It will be interesting to see the performance and mpg data in charge sustaining mode. If its faster than a prius but as efficient, I think we have a winner here (I remember the volt will have 50:50 weight distribution as well so fun to throw in the corners... with those LRR tires HAHA ok there buddy!)



I am afraid you have been misinformed sir !

Peugeot is developping a 1.0 liter 3 cylinders engines that will deliver up to 100HP, all diesels in europe have a turbo these days and the added maintenance is zero.

what data do you have to support that it will be faster and more efficient than a Prius ? with a weight above 3200 pounds , I seriously doubt that assertion is true.



You are correct as long as the power demands are modest, unless the battery retains substantial charge, ie, the engine kicks in before 40 miles are up. High speeds and/or long hills will probably deplete the remaining charge fairly quickly, leaving the engine to handle things. Perhaps they will offer two operating modes: one allowing more battery depletion and relatively little reserve, the other commanding the engine to kick in earlier to retain more battery capacity.



You are right and this is where this type of hydrid-series architecture shows its limit. Since you have 2 modes, one electric electric only and one HEV and you have to insure the same level of performance in both modes in every circumpstances you pretty much need to have 2 power train in one single car, then it is going to weight a lot and efficiency will suffer. GM faces a real risk that they will barely hit the 40 miles all electric so that in practice it will be significantly less. also GM targeted 50MPG in gas mode, there is rumors that they are far from this. This type of architecture would work better with a higly efficient mirco turbine or a free piston engine or even a rotary engine. Unfortunately these engines are not available.


tree does Peugeot work for GM? if you answered no why would they lend an engine like that for GM?

you know diesel emission equipment is costly right? its hard enough to keep it under 40 grand as it is.

The fact it has a bigger electric motor/batteries on board? And the fact GM is challenging Toyota HSD system over their E-Flex system, which is better?



Don't get me wrong, the Volts is a beautiful project and I sincerely hope it will works as initially claimed by GM since for the fisrt time in years GM has a vision. But my reservation is that such a project requires that you stick to the concept and what it requires to be successful. If you target efficiency you have to be lighter and streamlined to start with, the Volts is not, heavy and bulky to start with then it generates an inflation of weight and cost on every components and hard time to meet the performances. I looked in their reported number and it is clear that they will not meet the 40 miles range and the 50MPG initially claimed. The problem for that concept to work is that it requires a entirelly new platform and ICE that GM has not the time and money to afford, but anyway I think GM made thee right choice in term of concept extanded electric range, that's what people want rather thana electric, so the concept will survive but under another brand... maybe Hunday, or Mazda

Henry Gibson

I suggest that GM and the interested readers of this article and comments read the PDF-files that can be found on the AC Propulsion website about their Protoype car and their trailer range extender. Also the First TZERO and the high performance special built range extender for TZEROs.

The papers, basically, reveal that, in 1994, a workable electric car with an electric range of about 100 miles could be built from an existing chassis, a new design electric motor and electronic drive and a very large battery box that contained modern standard production Absorbed-Glass-Mat deep-cycle lead batteries. Lead batteries might be one-forth the cost or less of LI batteries of the same power and capacity. Plastic battery construction has reduced the weight greatly.

A range extender trailer was also developed with a small motorcycle engine to get an additional range of about 180 miles on about five gallons of gasoline. A ten gallon tank would double the range between ordinary gas station fillups. High speed driving reduces range considerably.

Range extender generators can be built into the vehicle, and battery weight and cost can be traded for the less weight of a smaller battery without much loss of fuel economy.

This was one of the first Plug-In-Hybrid cars and it was driven 30,000 miles in its first year.

It might have been better for GM to use a diesel light weight OPOC for its range extender and use GM's cash reserves to develop the technology into a super high-speed engine-generator to a market ready form.

The INNAS NOAX linear engine could and should be modified to produce electricity for such cars.

A mechanically less complicated unit might be a small revived Pescara opposed piston-turbine generator unit. Ceramic filters and thermo-catalytic converters can get rid of particulates and un-combusted fuel from the exhaust at lower costs. Computer control makes the efficient operation of engines much easier.... ..HG..


The weight of the Volt is an indication GM has not paid enough attention on weight reduction, but put too much emphasis on the drive-train. This is also a drive-train that is probably having some difficulty hitting the price point for wide adoption.

If GM can do a hybrid vehicle for $18,000 then they will be really doing something neat.

Know how to make the VOLT work GM?

"GM had said that it had yet to finalize its selection of the combustion engine component of the Volt powertrain,"

Here is my suggestion ...

Toss out the combustion engine component altogether.
Get Walmart to put recharge plugs in their parking lots.


This is all wrong!, GM must use a metallic-ceramic turbo compounded free revving diesel.. totally computer controlled without valves and a crankshaft, at least a 50m range and they have to do this under the cost of a Corolla otherwise no one will buy it..

These ignorant fools at GM, they are doing everything wrong!!.

Wait, wait.. let me take my lithium so I can calm down..


"I looked in their reported number and it is clear that they will not meet the 40 miles range"

Treehugger, you always seem to have access to these mysterious reports that are 100% conclusive. How is that? Please, share this source with the rest of us. I believe the very last announcement from GM indicated that the test mules, which haven't even been calibrated correctly, were already exceeding the 40 mile target.


Amazing... GM goes with an engine that is slightly heavier than the 1.0L and the ICE MPG will suffer slightly on the rare occasions when the ICE is even running and THIS is the cause of the desention??? Oh how horrible the MPG AFTER about 40 miles will be slightly less than a current Prius... how horrible, kill me now.



it is no mistery (go to their blog) and they made it clear that without regenerative braking they only reached 32 miles, and they only get 40 miles in case you have to break start and go, at 60MPH on a highway the Volts will not get the 40 Miles that is my understanding. What does that means ? that in practice nobody will get 40Miles but 35 Miles at best. But for this you need 200Kgs of 10 000$ batteries, so the all idea become questionnable about its viability.

Aptera : 1400 pounds; Cd 0.11, 10KWhrs batteries = 120 miles so ?

stas peterson


What's the matter? Is your AGW End- of-the-World nouveau religion dying in front of your eyes?

Its time to get a out a Sandwich board and start parading up and down Main street, proclaiming the End-of-the-World.

The World ended on July 28, 1999 per the OberstGruppenProfit Hansen; revised to July 28, 2005 by him; and now by the ReichsProfit Gore set for ten years from his new, newer, now Newest Revelation, so it set to end on July 21, 2016...

Returning to the subject, the Volt, and an engine family selection.

An analysis of trying to climb mountains when the SOC is already at 30%, would require a battery recharger to drive full 53KW rated generator output into the battery for extended amounts of time. The 1.2 turbo can't do that, as testing has revealed.

Besides, Why build a new factory for and old engine design? It will be phased out over time worldwide, by this new GM engine family, that already has a factory being built for it in Flint, to match the several already in operation worldwide.

Without turbo and in Atkinson mode, the 1.4 can generate 53KW in constant operation, even at high altitude.

When HCCI CI operation comes to GM, in a few years, it will happen on this engine family, early. Operating in the partial load mode that HCCI supports, the SFC of this family would be even more superior.

As it is, SFC may be superior even now, but it's doubtful in non-turbocharged mode. Close dual-turbo has already been designed for the engine family, and will show up in the Cruze; so EGR for HCCI is easy to add, in the future, directly from the parts bin. Since many turbos wuil be built, the cost to turboize an EREV version, will be much cheaper then, as well.

I suspect that may be then accompanied with a destroke or debore to about 1.1 liter, for Volt sized platforms. Modern engine plants can do mixtures of different sized engines very easily, unlike the inflexibilty of old transfer machine tools.

For example, the 'World engines' built by GEMA for Hundai, Mitsu, and Chrysler, says it can build a different 1.8, 2.0, or 2.4 engine on the line without slowing down.

The weight difference is probably less than +or-25 Kg in either direction and the new engine might actually be lighter, when dressed.

Using the new family is more adaptable. GM has said the Volt is only a pioneer platform for the EREV technology that will spread through many platforms. We have already seen ther Opel Flextreme and a Chinese Buick concept. A Chevy Impala or Cadillac DTS sized EREV auto, could easily be powered by the slightly larger version of the 1.4 HCCI turbo. A 1.6 turbo HCCI version, would probably suffice to power a Caddy DTS EREV, for example, driving a slightly larger rated generator.

It is somewhat disturubing to have to discuss engineering with closed minded, religious converts, who don't understand engineering issues, or the world about them.

George K

stas peterson,

Great info. that's not well known!

George K

stas peterson,

Great info. that's not well known!



It is very clear that you are going out of your way to try to find fault with this project, under the guise of your usual anti-GM sentiment. GM has been very clear that they are targeting the average short-distance commuter with the Volt, not the longer range highway traveler. As such, it is very likely that their target consumers will be hard pressed to get through their commutes without a heavy dose of braking. Your reasoning makes very little sense. Even if the range w/o braking was only 32 miles (which again, is on their earliest versions of their TEST MULES, not the actual Volt chassis), that is FANTASTIC! Is there any other 5-passenger vehicle out there that can travel 32 miles on pure electric power?


Probably a moot point, but if Treehugger read the article he was referencing, he would have seen this:

"When the plumbing necessary for the turbocharging and the balance shaft are added to the three, the overall package envelope works out about the same with the four being lighter."

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