GM Volt Gains a Cylinder, Loses a Turbo-charger

They might want to rename it "Corn"

OK, queue wing-nuts who say:

Volt is not an electric car!!!

:P

great to see some volt design choices with true efficiency in mind. i can't wait to see it in the market place.

So I assume if you run out of gas, you will begin using that last 30% of the charge. If you then refill the tank without plugging in, will the car begin to recharge the battery to 30% while you drive, or will it stay below 30% and just produce enough to move the car?

Also, I know there are many kinds of batteries with different needs as far as maintenance goes, but can I assume from this article that the Volt's battery never needs to be discharged fully?

"OK, queue wing-nuts who say:

Volt is not an electric car!!!"

It's not an electric car, it's a series hybrid. Do you understand the difference?

it might be a series hybrid, but it will be the first major company to bring a plug-in car to market.

(with the exception of the ev-1)

i hope it does come to market..!

series hybrid is an electric car by definition, duh

Some intelligent moves by GM.
Use a bigger but lighter engine that is more efficient in the steady state in which it will run.
Don't fully recharge the battery with the on board gasoline engine because it is much more efficient and cheaper to do it on the grid.

Good for them. Hopefully it will run Atkinson Cycle prius style for better thermal efficiency. Smart design move.

Added costs:
-extra piston
-extra con rod
-four more valve stems

Reduced costs:
-turbocharger
-wastegate
-intercooler
-spur gears
-counter rotating balance shaft (I3s have to be balanced)

Package will probably be about the same size. Note that the I4 will probably also see action in other GM vehicles in a slightly modified form and directly powering the wheels.

I think it is a shame that they are dropping the turbo. They should have incorporated the turbo with direct injection like Fords EcoBoost. The EcoBoost is suppose to almost be on par with a hybrid in terms of fuel economy just imagine combining the two WoW! I am waiting for the plug-in hybrind Ford Escape to replace my current Escape Hybrid.
www.FliteRecord.com

So if the car can run on a little 4 cylinder engine, by producing enough electricity, then whats the mpg if you take all the heavy batteries out?

"So if the car can run on a little 4 cylinder engine, by producing enough electricity, then whats the mpg if you take all the heavy batteries out?"

It would be higher than with the batteries, but the whole point of a plug-in is that you run the gas engine as little as possible. Most people drive less than 40 miles in a day.

Hmm... this seems like a good change on GM's part, but this is pretty limited range. How long does it take to charge the battery back to "full" on the grid? I don't see this becoming a road trip vehicle anytime soon, but I suppose that's not really the point. Good at least to see a major US company putting something like this out now. Assuming it makes it, as other commenters have astutely wondered....
I'm still waiting for someone to take advantage of the EEstor battery system.

"series hybrid is an electric car by definition, duh"

If a series hybrid is an "electric car," then so is a parallel hybrid. Which means a mild hybrid Yukon is an electric car, which is patently ridiculous. Hybrids are not electric cars, at least not in the definitions I learned when I got my automotive engineering degree. If you want to make up your own definitions for words and expect others to abide by them, then by definition, you are a wingnut. Duh.

BTW, I'm looking forward to the Volt coming to market. It's an important technology. If it's not a total disaster like so many other GM products in the past, and the next gen Prius doesn't make a huge leap past it, I'll most likely buy one. GM has turned out a few good vehicles lately, so I have hope.

Timbuktu said:

"this is pretty limited range. [...] I don't see this becoming a road trip vehicle anytime soon,"

What the hell are you talking about? That's not 40 miles while the engine is running. That's 40 miles without even starting the engine. Then the engine runs until you either run out of gas, or you plug it back in, or you turn it off. This is pretty much the definition of a road trip, isn't it?

Nevermind the inevitable stops for the things that every human being must do. You can quick-charge while you're waiting for those to happen too, thus dramatically reducing the cost of your road trip. Modern batteries can fill up in only a few minutes with the right kind of charging station.

With Range Extended Electric Vehicles, REEV, AKA PHEV, you only need a electric only range as much as your normal daily driving for 85% of the time. So if you drive 18 miles round trip to work, than you only need that much usable range. This saves a lot of battery, which saves weight, energy (either gas or electric) and it saves cost.

The volt should have options of 20mile 30 mile and 40 mile battery packs.

As for "Volt is not an electric car":

Although I do not have an automotive engineering degree to back this up, by my personal definition it is an electric car for two reasons:

1. Electricity is the soul means of powering its locomotion (electricity always has to come from somewhere...)
2. It can travel x distance (40 miles in this case) on pure electric power.

I seriously hope that GM delivers, and that they can make it affordable as promised. It is the perfect gap technology between current tech and hugely better batteries / alternative power sources.

It's a shame to put in a 1.4 liter engine and only maintain a minimal charge level while the car is moving. If it would charge the batteries and then cycle itself back off until it went back down to 30% electric charge, it's fuel economy on a road trip would be far more impressive. IF you happen to believe that is the goal of this PR project.

I imagine the turbo was also a potential warranty issue as well. Turbo's add complexity which in of itself is a warranty issue, but turbo's don't like to get really hot and then turn off quickly, which I imagine would happen in this application.

If the ICE only maintains charge, it should be sized slightly larger than the average power drain, and 1.4L seems really large. It's relatively easy to achieve 100HP/L normally aspirated in a high performance MPFI DOHC motor.

It makes me wonder if Honda and Suzuki with their motorcycle divisions and ~100HP "small" 600cc motorcycle engines could severely reduce the motor RPM in this kind of application and still produce 40-50HP in a much smaller and lighter package and achieve more reliability than even in the motorcycle applications due to the reduced RPM's.

BWDIK :)

"It's a shame to put in a 1.4 liter engine and only maintain a minimal charge level while the car is moving. If it would charge the batteries and then cycle itself back off until it went back down to 30% electric charge, it's fuel economy on a road trip would be far more impressive. IF you happen to believe that is the goal of this PR project."

If the engine had to charge the car, it would be working to not only move the car, but to also charge the battery beyond what is necessary. It's more efficient to just supply enough electricity to move the car and to hold off on 100% recharging of the battery pack until the driver has access to grid electricity.

"If a series hybrid is an "electric car," then so is a parallel hybrid. Which means a mild hybrid Yukon is an electric car, which is patently ridiculous. Hybrids are not electric cars, at least not in the definitions I learned when I got my automotive engineering degree. If you want to make up your own definitions for words and expect others to abide by them, then by definition, you are a wingnut. Duh."

Why don't you look up how the drivetrain works then rather than just calling people names? The drivetrain is entirely electric-- it just has two options for charging the battery, either an onboard ICE or grid electricty. There's nothing but electricity moving the car; no mechanical link between the ICE and the wheels. Think of it like an R/C car, it's run off a battery pack, but you have two choices for charging the battery when it's out of juice, either the wall socket or the generator in your tool shed.

The reason they're called series hybrids rather than just electric vehicles is because they have an ICE. It's semantics. Why don't we call the Tesla Roadster a coal car because in some places, people will get their electricity from a coal power plant?

Parallel hybrids are very different from series hybrids. In parallel hybrids, the ICEs are still connected mechanically to the wheels.

"Hmm... this seems like a good change on GM's part, but this is pretty limited range. "

The car, when using the ICE to generate electricity for the battery, should have a range over 300mi, just like any other standard vehicle.

"So if the car can run on a little 4 cylinder engine, by producing enough electricity, then whats the mpg if you take all the heavy batteries out?"

Well, the Volt's mpg when driving under 40mi per day will be extremely high, with significantly lower carbon impact even if your electricity comes from coal. The ICE gets to be very efficient by running at it's optimally efficient speed when charging the battery. If you took the batteries out and ran the car solely off the electric charge created by the ICE, then the ICE would have to vary it's speed based on the necessary output.

You could use a smaller battery pack, but then you'd be using the engine more often than not. The goal is to eventually provide an infrastructure of quick charge stations, like gas stations, where people can keep the battery topped off. As battery technology improves, larger batteries can be installed for longer trips without having to use the ICE assist.

"I think it is a shame that they are dropping the turbo."

Using the I4 instead of the 3-cyl turbo probably has significantly lower total cost, by removing the initial cost and eventual maintenance costs of the turbo. If GM plans to use a modified version of an existing I4 engine, like the Eco-Tec, then they also get the benefit of economies of scale for the manufacturing of the engine, shared spare parts, and existing production and maintenance knowledge.

Folks, as an "retired" engineer I think maybe I can clear some things up here.

#1 - Hybrid cars ARE not electric cars.
#2 - Plug-In Hybrid cars ARE not electric cars
#3 - Plug-in cars ARE not electric cars.

All three types of cars: hybrids, plugin hybrids, and plugins, ALL get energy from a source that is more than likely a carbon based fuel that creates heat, which then in turn is turned into energy.

A hybrid converts this heat energy very efficiently compaired to ANY electric car BECAUSE>>>> the thermodynamic power cycle of an internal combustion engine IS more efficient than the thermodynamic cycle (Rankin) used at the power plant to create electricity. The differences in thermo efficiencies alone makes the hybrid only MUCH more efficient than ANY... note... ANY plug in hybrid.

The reason batteries and electric motors work in hybrids better than a standard cars transmission, is because you can run the engine nice and evenly at its maximum horsepower all the time. The batteries..."smooth out" the performance.

But at the end of the day, you still have to get that power from someplace. Plugging into the grid doesn't mean some magical power fairy generated the electricity.

Cheers,
Signed a Mechanical Engineer

OK Ken,

Then, what constitutes an Electric Car?

A wind / solar array that charges a car with nothing on it but batteries and an electric motor?

One that is charged from a capacitor juiced up by lightning?? ... electric eels?

Maybe I can strap my bike to a couple of generators and hook up to the car's batteries to charge them? Maybe I can walk along new carpet, dragging my feet and zap it with static shocks.

Plug it in , plug it in.

vsk

First change the design of the body to be a "SPUD". Then change the ideal 3 cylinder 1L turbo engine to a 1.4L 4 cylinder "STONE" . Great work. What next? You start with a car Americans would be proud to own and will end with a car nobody wants. It seems there is no helping the auto industry in America. Perhaps the education system, perhaps the arrogant culture- nonetheless everyone will be disappointed and ashamed to have had any hope for GM.

Maybe I'm missing the point? Why would you put a turbo on a "stationary" engine that is only running a generator? Wouldn't the engine always run at the same RPM?
Aren't turbos usually used to get some 'oomph' on acceleration? I guess even at a static RPM, the turbo provides the extra HP that a 1L wouldn't normally have? However, I agree with the "keep it simple" direction GM is taking by removing the turbo. one less failure point.
If this is even half as good as it looks, GM may be hitting a triple, if not a HR. Beats a $12k Smart that gets only 30mpg

"First change the design of the body to be a "SPUD". Then change the ideal 3 cylinder 1L turbo engine to a 1.4L 4 cylinder "STONE" . Great work. What next? You start with a car Americans would be proud to own and will end with a car nobody wants. It seems there is no helping the auto industry in America. "

Talk about negativity. Did you even see the show car firsthand? It was a show car! The visibility was terrible. It was as aerodynamic as a brick. The ingress/egress was abominable. The production car looks better than all the other goofy hybrid/electric cars out there except for perhaps the Tesla.

The four cylinder is an upgrade. It is smoother, lighter, more efficient, and cheaper. The idea is to have an engine you don’t know is on. A turbo doesn’t make sense on a constant speed, constant load engine. The battery pack provides the power boosting. Pressure boosting just means more heat is going out the exhaust, because they have to run lower compression to prevent detonation. It was a good move.

Response to "Mechanical Engineer"

The drive train of a hybrid and conventional cars is no wheres near as efficient as your coal, oil, or natural gas plants. They almost all run in the 90% efficiency, with modern plants near 96%.

Your ICE only manages to get about 20% of the produced energy to the drivetrain. The rest is waste heat.

And by your definition of an electric car it doesnt exist, save maybe a solar electric car, which will likely never be feasible until we get beyond the 18-21% efficiency range of solar cells. Even if we have a 90% cell, it wouldnt be feasible for many applications except vehicles that only have low daily mileage and would be limited to day use (save an exceptional battery system with the car, which adds weight, and reduces daytime efficiency).