Chevy Volt - How's it work?
Chevy Volt - How's it work?
(OP)
Chevy says it can go about 40 miles on batteries alone but can go another 200 or so miles using a small IC engine that recharges the batteries. So, in effect, the "small" IC engine is moving the car. I'm assuming that performance (acceleration and top speed) are drastically reduced when running on the engine. Or am I missing something?





RE: Chevy Volt - How's it work?
This is just a series hybrid with a big battery. It seems that GM are trying to convince the journalists and prospective customers otherwise. They don't use the word hybrid and refer to the engine as a "range extender".
From what I've read, they're trying to claim that the fuel economy should be measured in such a way that it ignores the fuel used to charge the battery when it's plugged in overnight. EPA tests usually require the battery to be in the same state of charge at each end of the test (i.e. sensible).
Letting the battery discharge during the conomy test is exactly the same as starting your economy test at the top of a hill.
This car could be another "breakthrough in marketing".
- Steve
RE: Chevy Volt - How's it work?
RE: Chevy Volt - How's it work?
And by the way... prior to 2008 (and maybe even now?) the EPA did not require that a hybrid's battery be in the same state as at the beginning of the test.
A plug in hybrid is a bit of a different animal than a car that gets all of it's energy from gas. It's an issue because it is illegal for the automakers to advertise any mpg except the EPA's test.
-b
RE: Chevy Volt - How's it work?
RE: Chevy Volt - How's it work?
RE: Chevy Volt - How's it work?
I am not very familiar with the Tesla, but will it seat 4 passengers, obtain 4-5 star crash ratings, etc.? My guess is that it is more of a performance car, thus it weighs considerably less, and will have a retail cost significantly higher than that of the Chevy Volt.
RE: Chevy Volt - How's it work?
The "range" on a long trip that uses up the designed 70% charge, is no different from a gasoline vehicle and you treat it the same way. When the gas gauge goes to empty, you fill it up and keep going, obviously on gasoline power (driving the generator which maintains the state of charge at about 30%).
The Volt is *designed* to be plugged in every night to recharge it. It is an electric car with a range-extending gasoline engine so that it can do long trips. If you don't plug it in, you lose the benefit of running on stored electric power, but at least the car will DO it.
RE: Chevy Volt - How's it work?
RE: Chevy Volt - How's it work?
The car runs on batteries alone, without gasoline engine operation at all, until the state of charge reaches about 30%. At that point, the car continues running on batteries but the engine starts and recharges them at the same time, so the car keeps going (on "net" gasoline power) and the state of charge is kept at about 30% by running the engine to roughly match power demand. It will go as long as the tank of fuel will last in this mode just like a regular car, and you can fill up the tank and keep right on going, just like a regular car. When the opportunity arises to plug the car in ... the batteries charge to 100% and this process can be repeated. From the point of view of "running out of fuel" there is not ever a "need" to plug in the battery ... but if you don't, you will not get the fuel saving benefit of the plug-in hybrid system.
RE: Chevy Volt - How's it work?
It's only really tax saving. Fuel is burned elsewhere, with much less tax than anything you can buy at a pump.
And we all know that when tax-saving schemes become popular, they disappear.
- Steve
RE: Chevy Volt - How's it work?
RE: Chevy Volt - How's it work?
They may not be burning gasoline at the power station, but it's more than likely some form of hydrocarbon fuel that's being used to "fill" the battery.
- Steve
RE: Chevy Volt - How's it work?
-b
RE: Chevy Volt - How's it work?
When you get down to that 30% level then all the car's power needs are coming from the gas, right? That's where I don't understand how you can get by with what is called a "small" IC engine. Performance of the car must be limited at that point, right? Or is it that the electric drive is more efficient at getting power to the wheels?
RE: Chevy Volt - How's it work?
RE: Chevy Volt - How's it work?
Here in Canada, a very large fraction of the electricity is hydroelectric or nuclear. Wind power is still a small fraction but gaining fast.
The taxation point is a good one, and if plug-in vehicles become popular, I wonder how long it would take the authorities to do something about this.
RE: Chevy Volt - How's it work?
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Chevy Volt - How's it work?
All in all, it has given me some pause regarding a plug in car. I had more devices to plug in than I had generator capacity to accommodate.
rmw
RE: Chevy Volt - How's it work?
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Chevy Volt - How's it work?
bvanhiel : I'm pretty sure the tow rating on the Volt will be zero.
Here in SC 50% of our electricity already comes from nuke plants and they are getting geared up to build more.
RE: Chevy Volt - How's it work?
- Steve
RE: Chevy Volt - How's it work?
RE: Chevy Volt - How's it work?
I guarantee someone will try.
-b
RE: Chevy Volt - How's it work?
RE: Chevy Volt - How's it work?
Luck is a difficult thing to verify and therefore should be tested often. - Me
RE: Chevy Volt - How's it work?
Try using 120 kW continuously on any road with the possible exception of the autobahn and the Nürburgring and your license won't last long. If anything, given the attention given to the Volt's aerodynamics 53 kW should get you (un)comfortably over the speed limit on a flat road.
RE: Chevy Volt - How's it work?
- Steve
RE: Chevy Volt - How's it work?
-b
RE: Chevy Volt - How's it work?
-b
RE: Chevy Volt - How's it work?
53kW is fairly piddly for a 1L IC engine though. At least it is in the civilised world...
- Steve
RE: Chevy Volt - How's it work?
RE: Chevy Volt - How's it work?
As you say it'll be tuned for optimum bsfc, for a very limited number of operating points, and will then use the electric drive as a CVT.
So if they've got their heads screwed on they should manage >30% thermodynamic efficiency across the entire operating range.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Chevy Volt - How's it work?
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Chevy Volt - How's it work?
- Steve
RE: Chevy Volt - How's it work?
- Steve
RE: Chevy Volt - How's it work?
RE: Chevy Volt - How's it work?
GM already has a small-engine family of 1.0, 1.2, and 1.4 litres which are all the same basic design, and this is one of them. The Cruze will use the same basic engine, but with a turbo.
"why not the 1.0" - probably market acceptability, probably noise level during highway driving, etc.
A smaller engine isn't necessarily the most efficient. The RIGHT-sized engine is the most efficient.
RE: Chevy Volt - How's it work?
Apparently that info is available somewhere on this website http://media.gm.com/volt/# , I was told about it rather than finding it.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Chevy Volt - How's it work?
All the WWW mentions of the Paxman Valenta engine state that it develops 2250 BHP at 1500 rev/min. But if you listen, you can clearly hear different engine speeds and loads in different situations. From (vague, beery) memory the engines seem to run at two distinct speeds. I suppose one is best BSFC (flat running), the other, rated power (acceleration & hill climbing).
- Steve
RE: Chevy Volt - How's it work?
- Kyle
Kyle Chandler
www.chiefengineering.net
"To the Pessimist, the glass is half-empty. To the Optimist, the glass is half-full. To the Engineer, the glass is twice as large as it needs to be!"
RE: Chevy Volt - How's it work?
RE: Chevy Volt - How's it work?
Kyle Chandler
www.chiefengineering.net
"To the Pessimist, the glass is half-empty. To the Optimist, the glass is half-full. To the Engineer, the glass is twice as large as it needs to be!"
RE: Chevy Volt - How's it work?
It can charge itself at night when the day/night rates drop to their cheapest.
The engine generator battery inverter could provide emergency power at home or anywhere if needed. One Volt could jump charge another if ever a problem arose.
You could charge the batteries form a special internal combustion engine/furnace that generates power while it heats your home.
The goal is to waste as little heat as possible.
This site has a few good articles http://autoelectronics.com/
Vin
RE: Chevy Volt - How's it work?
RE: Chevy Volt - How's it work?
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers for professional engineers
RE: Chevy Volt - How's it work?
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.