Putting Thought into Putting Gas in the Chevy Volt

· · 4 years ago

If you own the Chevy Volt and drive less than 40 miles a day, then you will almost never have to visit a gas station. General Motors engineers took this into consideration when developing the gasoline storage system on the Volt. I recently had the chance to gas up the Volt, and learned just how much technology and computing power was applied to the refueling event. After all, when your car needs a gas fill-up only a few times a year, you have to make sure that storing gasoline for weeks or months won’t increase emissions.

To release the gas nozzle inlet, located on the rear passenger side, the driver pushes a small button on the driver’s door. The gas release button is a little hard to see at first, but it’s right above the electric charging inlet release button. (The charging inlet, where you juice up on electricity every day, is on the front driver-side of the car.)

When you hold and release the gas door button, you need to wait a moment. An indicator on the dash tells you to “wait to refuel.” That gives a vacuum pump enough time to evacuate the pressurized tank and pump the vapors into a carbon canister. The gas tank is otherwise completely sealed.

The Volt’s computer system is monitoring this activity—keeping track when the gas door opens and closes, how much time has passed, and how many EV miles you’ve driven since the gas engine was last called into action. If you open the gas door, but don’t put in any gas, the Volt knows. The car’s system is double-checking to make sure that new fuel has been added, because old stale gasoline is potentially bad for the system and bad for emissions. An outside temperature sensor is even keeping track of hot days to determine if the fuel might be cooking.

If you haven’t burned fuel for a while, the dashboard display will encourage you to burn some gas, by driving the vehicle beyond its 40 miles battery-supplied power. You can ignore the call to action, but after two warnings about the need to drive using some gasoline, the car will take matters into its own hands. The Volt will then start up the gas engine in order to burn off stale gasoline, circulate engine oil, and pressurize the engine system.

When the car completes this “engine and fuel maintenance mode,” it shuts down again, giving the reins solely back to the electric motor. At that point—for drivers who stay close to home—the gasoline is again left in reserve for days, weeks or months, until your next rare and infrequent trip to the pumps.

Comments

· · 4 years ago

My first thought is very cool. I like tech. Sounds good. The other half then shortly screams "More stuff to breakdown!" I so look forward to the simplicity of a BEV.

· · 4 years ago

Hey Scott - I thought the same thing. Producing a plug-in hybrid (or extended-range EV), and getting those extra few hundred miles of range, definitely adds complexity. For those who really need the extra range, the technology will be there. Choices are good.

· Indiana Chevy Dealers (not verified) · 4 years ago

Brad,

Interesting post. I have heard lots of discussion around the Volt but this is the first time Ive read about this specific topic. I would love to promote this cool technology but wonder how much of a backlash there will be for having to burn some gasoline. I understand the reasons why it needs to be done and am amazed at the tech involved but wonder what your thoughts on public perception will be before I publicize this.

Chris Theisen
Director of Digital Communications
Hare Chevrolet

· · 4 years ago

I think the solution will be to never fill the gas tank unless you really will need the gas.
This way, if you only put 1/2 gallon of gas in the tank, you only have to burn off 1/2 gallon.
Folks who like to keep spare gas in the tank will suffer by having to burn the whole thing off every 3 months or so. If you run out of charge and the ICE starts up, you'll have to get to a gas station quickly.
It will be an interesting dynamic.

· Skip (not verified) · 4 years ago

Would treating the gasoline with a stabilizer be harmful in any way? There are quite a few very good ones on the market.

· · 4 years ago

Nice post Brad. One question though. How much of the gasoline is burned when the car "takes matters in it's own hands" Lets say I filled the tank (Although I wouldn't, I would use ex EV-1's plan) and only drove short trips and never needed the charge sustaining mode so the engine turned on by itself as you described. Would it burn the entire 8 or 9 gallon tank to get rid of all the "stale" gas or would it just run for 15 minutes or so to lubricate everything and then shut down for another few months?

· Joe (not verified) · 4 years ago

Gm Has a New Patent For a device for fuel stabilizer that would inject @ certain times. A feature on Next Version of the Volt in Planning.

· Robert (not verified) · 4 years ago

How much Gas did it take? and what range did it add?

· Chacama (not verified) · 4 years ago

At first I considered the solution presented by "ex-EV1 driver" a little dumb but when on second thought it is actually a good idea although not for the stabilizing issue since it is related to degradation of the fuel and Oxygen (that's why GM have the Volt's tank pressurized).

If you live near work and your commute is less than 40miles and you plan to recharge every night while sleeping, why carry around 9 gal on pure EV which adds 50lbs on dead weight when less than half of it should be more than enough for daily commutes?

· · 4 years ago

I can already see that Volt drivers will need to figure out exactly how much gas to carry--based on how much they expect to drive. The short commuters will keep just a gallon or two--while the long-distance guys who know that they will be driving 40+ on a regular basis might fill all the way up--because they know they will be burning it off.

Tom, I don't know how long the engine will run in those burn-off modes. Good question. I wonder if that will depend on how much gas is in the tank.

Keep in mind that Mountain Mode basically functions to force on the engine and charge up the batteries via gasoline. So, drivers can choose to burn down some gasoline (kinda the opposite of what you want to do most of the time).

Chris - I would say that this stuff can definitely be promoted. It's cool technology. Not necessarily cooler than 100 percent EV--but as far as plug-in hybrids go, the Volt will be as sophisticated as it gets. Most consumers will be impressed--and should be--even if it's not the pure zero emissions that some folks want. It does what plug-in hybrids are supposed to do--give mostly EV driving with extra range.

· VinceP (not verified) · 4 years ago

Hello- I'm a GM tech who just completed some training on the LUU 1.4l engine that will be in the Volt. to Tom- I asked that same question regarding how much fuel would be burned during a fuel maintenance mode and the answer I got was that the Volt's computer systems calculate the average age of the fuel in the tank, If the average age reaches roughly 1 year, the engine will burn the stale fuel and "prompt a refueling event" in other words, run it out or close to out of gas. That is "Fuel Mantenance" mode. If the engine goes roughly 6 weeks without starting, then it will enter "Engine maintenance mode" and run for about 10 minutes to keep everything lubricated inside the engine. Given that, I wold imagine it to be pretty rare to have the average age of the fuel in the tank be over 1 year. I'm sure all of this is subject to change, but this is how we GM techs were recently taught.

· · 4 years ago

Thank you Vincent! It's great to get feedback from GM employees. I was wondering if it would ever determine that all the fuel needed to be burned and it sounds like yes, if it is one year old. Very reasonable.

· evnow (not verified) · 4 years ago

Volt/Ampera has a switch which you can use to run ICE even when battery is not depleted - but only in EU. That would come handy here.

BTW, if some doesn't use ICE for a year shouldn't they buy a BEV ?

· Gereon (not verified) · 4 years ago

Dear Brad,

wouldn't it make much sense, at least for some markets, to offering that 1.4-engine LPG-capable? If I am not mistaken, this mixture of Propane and Butane doesn't get stale (correct me, if I am wrong) and in addition it further would decrease the overall costs of operation. For example, over here in Germany, where I am living, LPG not even is half the price of gasoline, due to the tax-breaks our government grants because of the environmental advantages of LPG. I already did submit a corresponding proposal to Opel, related to the Ampera. Best regards, Gereon

· · 4 years ago

evnow said: "BTW, if some doesn't use ICE for a year shouldn't they buy a BEV ?"

Yes, in my opinion they most certainly should. However you have to remember there are a lot of people that worry about the terrible, debilitating condition of range anxiety and fear they will get it if they buy a car that cannot go 400 miles between refueling. I think a lot of people that eventually buy a volt could probably live just fine with a 100 mile BEV but hey, it's their money. I'm not saying that everyone could, not by a long shot. There are plenty of folks that want an electric car but because of their driving needs a pure EV just won't work. The volt is perfect for them and should sell very well because there are a lot of people in this segment.

However I do read many comments on various online blogs from people that claim they are going to buy a volt and that they won't need to buy gas more than once or twice a year. If that truly is the case than they are spending a lot of money on a lot of technology that they really don't need. However like I said, hey, it's their money.

· Loboc (not verified) · 4 years ago

I really like these kind of detailed articles. Keep em coming!

· Anonymous (not verified) · 4 years ago

Bring back non-Ethanol gas. Then we won't need all of this nonsense. It's the Ethanol in the gas that causes problems when gas gets stale.

· thoughtchallenge (not verified) · 4 years ago

People and especially editorial writers need to start crunching the numbers, before they pass judgment on the cost. I like this article for its in depth analysis of practical uses. The question of maintenance is an obvious one given the vehicles advancement in technology. If you drive less than 50 miles per day, then you will rarely use the generator and hence require very little maintenance. Think infrequent oil and air filter changes, they will actually add over the life of the car. If the Volt is like other Electric vehicles it will require very little maintenance to the motor and batteries.

My analysis of the costs versus savings showed potential savings for buyers who fit the demographic mold, but the Prius saved a comparable amount of money. High gasoline prices yield a very significant competitive advantage for the Volt however. Higher rates of production will likely reduce battery costs in second and third generation cars. Also, the technology has room for improvement, such as lighter longer lasting batteries, or generator improvements. Finally, I would look for this technology to move more upstream into the luxury car and truck markets, where the advantages are more pronounced. Who wouldn't like a truck that gets 125 MPG?

· kevin (not verified) · 4 years ago

If one rarely uses the gas engine, then why have all the weight (and cost) of these gas-related parts? I mean how often have any of us, just on a whim, driven 300 miles instead of 40 miles? Used only in pure-EV mode the Volt seems to be a solution looking for a problem, so it makes little sense to mention its completely gas-free benefits to consumers.

I figure everything gas-related weighs about 500 lbs and costs about $8000. So people who routinely drive in EV-only mode should start to question the usefulness of lugging around a gas engine not being used. I was hoping the Volt would come with a BEV-option for a second battery that costs as much as the replaced gas-related parts, but oh well, maybe in 2013.

· Priusmaniac (not verified) · 4 years ago

A few comment I like to do on the article and former comments themselves.
The idea of forcing the engine to start designed in a software and imposed on the owner is not a good one. At first, it is then better to have a small run at the garage during maintenance, at second since the volt can encounter that situation of stale gas the engine should simply be able to cope with it from the start. It is not because it is only a 1.4 liter that it has to be low tech, at contrary. By the way, it should be much more compact and more like a 0.6 liter engine in a shoebox size then a relatively large 1.4. But well, someone has to start somewhere.
One comment stated that ethanol should be removed from the gasoline to avoid stale gas problem. Actually, I would remember that the other interesting element of the volt is its supposed ability to drive as a flex-fuel vehicle on E85. Thus with almost no gasoline in it to stale. It would in that respect be interesting to use the Volvo type engine able to run on E100, thus pure ethanol. Since pure ethanol is very stable, the stale problem will be solved. The Volvo engine is also more compact because it is turbo equipped. For the volt, the turbo isn’t really needed because cold start of the ICE could be delayed due to sufficient EV mode reserves in the car. E30 can also be interesting since water doesn’t separate anymore from the mix starting at those concentrations and up. Ultimately, I see a direct piston generator running on E85 or E100 or even 95% ethanol with water as the remainder. This last fuel would save the costly drying step in the production process and eliminate any water absorption problems defacto.

· tydesigns (not verified) · 3 years ago

I would like to know what's the solution for people living in the suburbs of big cities who drive 50+ miles to work each way (there's a LOT here in DC area). There are plenty of other EVs coming out after 2012. And with the turmoil going on in the middle east, our gas is at $3.30 right now. I'd love to get rid of my ICE truck and car and get something better.

· Michael (not verified) · 3 years ago

@Anonymous,
"Bring back non-Ethanol gas. Then we won't need all of this nonsense. It's the Ethanol in the gas that causes problems when gas gets stale."

Not true. Gasoline without Ethanol also went bad. Even gas from the old days, without any emissions additives, went bad and gummed up carburetors.

· Michael (not verified) · 3 years ago

@Priusmaniac,

"The idea of forcing the engine to start designed in a software and imposed on the owner is not a good one. At first, it is then better to have a small run at the garage during maintenance, at second since the volt can encounter that situation of stale gas the engine should simply be able to cope with it from the start."

Most people would not have to take their car to the shop enough to run the maintenance mode enough. Also I don't think 10 minutes of running is going to bother anyone.

" It is not because it is only a 1.4 liter that it has to be low tech, at contrary. By the way, it should be much more compact and more like a 0.6 liter engine in a shoebox size then a relatively large 1.4. But well, someone has to start somewhere."

I don't see how a 0.6L engine is going to do the job, when the 1.4L is already near full throttle in charging mode.

· Anonymous (not verified) · 3 years ago

Ethanol does severely reduce gas shelf life at least at the 10% mark.
Regular gas without Ethanol as someone else mentioned gums things up as well but regular gas can sit upwards of 1 year without issue.
I live in Florida and the humidity here adds water to Ethanol in as little as 1.5 months. so this car will not work for me... I have flushed more injectors and carburetors this past year more than I care to admit. I am jaded from the volt anyhow as GM lied when introducing this car. It is a plug in Hybrid as the engine is physically connected to the drive-line and can push the car. it is not strictly a generator for the EV batteries for the car as we were initially lead to believe. I would rather drive a Nissan Leaf for daily commutes and install a solar panel grid to drive the car $$ free without ever having to think about a gas station. I realize this is just my opinion and the Volt is probably a great car for folks who need the range.
Does the volt's software even support not filling the gas tank?

· Guzzler (not verified) · 2 years ago

The Volt is definitely NOT a HYBRID. There is no mechanical connection from the wheels to the engine like a Prius, Civic Hybrid or any other H designated vehicle. The gas engine is purely a generator, the same as a gas generator used to power up homes during power outages. The drivetrain uses regenerative braking to turn the propulsion motors into generators during braking the same as any hybrid does. For the uninformed, an electric motor that uses electricity to propel can also absorb energy in order to supply electricity in the reverse direction. It is very efficient to use the inertia of a vehicle to make electricity while slowing down. A positive by-product is less breake wear since the motors create drag on their own. Search eddy current brake if you want more info. Annon is an idiot that knows nothing about the drivetrain of the Volt. Personally, I think small diesels are the way to go for at least the next decad ebut I had to comment seeing that someone completely uninformed was spewing lies about what the Volt is.
--- GM tech

· · 2 years ago

@Guzzler, You are mistaken. Under some circumstances the engine in the Volt does link directly to the wheels through a clutch system. This is done because at higher speeds (loads) it is more efficient to use engine power directly than to just use it as a generator. However, this makes the Volt somewhat more complicated mechanically than it would be if the car was a pure series hybrid (in which the engine acts as generator only).

As for the Volt not being a "hybrid", that's absurd. Of course it is, since it uses two sources of power, which is the definition of hybrid. The distinction you are trying to draw is between a parallel hybrid and a series hybrid. The Volt acts as both, depending on the driving conditions.

· Guzzler (not verified) · 2 years ago

"The Volt is the most fuel-efficient compact car sold in the United States, as rated by the United States Environmental Protection Agency (EPA).[3][4] The Volt operates as a pure battery electric vehicle until its plug-in battery capacity drops to a predetermined threshold from full charge, at which point its gasoline engine POWERS AN ELECTRIC GENERATOR to extend the vehicle's range. It is a hybrid only in the sense that it has two power supplies on board. There is absolutely ZERO mechanical coupling between the gas generator and the electric motors. More clearly, the car wont move one inch if the battery is dead. There is no clutch, no torque convertor no nothing. The engine drives a generator that hooks to the battery via electrical cables and thats it. Think of it as a Nissan Leaf with a gas generator sitting on a trailer behind it that turns on when the batteries get low to recharge them.

Hell, look up Wikipedia for christ sakes, its in the first paragraph and that is what I quoted from. So PLEASE get a clue. I work on the friggin things.

· Anonymous (not verified) · 2 years ago

Is the Volt fuel tank galvanized steel or a plastic based composite? The chief problem of long term gasoline storage, as in motorcycle storage, is internal tank rust. Besides using a fuel stabilizer, a full tank to help reduce tank condensation and to reduce the internal surface exposure to oxygen is the optimal way to reduce internal tank corrosion.
Out of habit, because of my motorcycle experience, I keep the tank of my Volt topped up. I have driven about 1800 miles in Jan and Feb. and have used slightly more than a total of 4 gallons. Overall, my Volt has exceeded all my expectations. A great car.

· Anonymous (not verified) · 2 years ago

Is the Volt fuel tank galvanized steel or a plastic based composite? The chief problem of long term gasoline storage, as in motorcycle storage, is internal tank rust. Besides using a fuel stabilizer, a full tank to help reduce tank condensation and to reduce the internal surface exposure to oxygen is the optimal way to reduce internal tank corrosion.
Out of habit, because of my motorcycle experience, I keep the tank of my Volt topped up. I have driven about 1800 miles in Jan and Feb. and have used slightly more than a total of 4 gallons. Overall, my Volt has exceeded all my expectations. A great car.

· · 2 years ago

@Guzzler, For someone who claims to work on the cars you don't know very much about them. While it is true that the car won't function on the gas engine alone, since it is primarily driven by the electric motor, under some circumstances it uses a mechanical linkage from the engine to the motor to assist it, rather than just acting as a generator. If you would like to learn more about it you can read this:
http://www.plugincars.com/exclusive-chevrolet-volt-chief-engineer-explai...

The car isn't a "pure" series hybrid in the usual sense of the term but it usually operates as a series hybrid.

· Anonymous (not verified) · 2 years ago

Question about the self start maintenance. Does this happen when driving? I wouldn't want the car to start up in my garage.

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