230 mpg in the Volt? Chevy fudging the numbers?

[jamesqf]

Originally Posted by MetroMPG

What happens when you drive 230 miles in a Volt? You use way more than 1 gallon of gas.

Sure, but how often do you drive 230 miles in a day? (If you do it frequently, maybe the Volt isn't the right car for you.)

I think people are just going to have to get used to the fact that with plug-in hybrids, there's no one number that everyone can agree on for mpg. If you lived in a moderate climate (so you never needed heat or A/C), and always drove less that 40 miles a trip, you'd get infinite mpg. If you left home one morning and drove across the country without ever recharging the batteries, you'd get closer to the 40 to 60 mpg figure.

[dcb]

Originally Posted by mcmahon.craig

I disagree. In the not-yet-a-series-hybrid project we have been working on for some time (a Porsche 914) we figure the opposite is true.

You are not selling it as a 230mpg vehicle. In order to make those claims, the user HAS to plug it in. If you recharge completely with gas then what's the point?

I don't mean to say that the engine shouldn't run at bsfc and recharge for a bit, but it should have a management scheme where it does not recharge the battery completely is all, otherwise the electric only miles get thrown out the window.

[dcb]

LOL, do an alternator delete on a VOLT , and an engine delete while you are there

[PA32R]

Originally Posted by Christ

Well, the 230 MPG mark is potentially true for the 51.1 mile drive cycle, but the further you go before recharging, the less your average miles per gallon becomes.

Bingo. See Rhett Alain's Dot Physics entry on this.

Other analyses are at Good math, bad math and (blushing) my own little blog.

All that said, GM will claim "we're just doing as the EPA is saying they will do."

[MadisonMPG]

Originally Posted by dcb

LOL, do an alternator delete on a VOLT , and an engine delete while you are there

haha an engine delete is probably the best thing for mileage. Maybe add it's weight in batteries.

[aerohead]

The car was tested on the surface of the Moon.

[cfg83]

Hello -

I just noticed that the Zenn EV has a (self?) rating of 280 MPG :



Question: If we apply the Zenn "kind" of calculation to the Volt, what MPG do you think it would get?

CarloSW2

[NeilBlanchard]

Hi,

Here's a post in a parallel thread over at the Aptera Forum:

ApteraForum.com - Aptera Car Forum - View Single Post - GM claims 230MPG for the Volt, is a 300MPG rating for the Aptera too conservative?

[aerohead]

"For CAFE purposes,every EV sold will count as a 200-to 400-mpg ( 1.2-to 0.6L/km ) car under the 1988 Alternative Fuels Act." ( from Ward's Auto World,June 1992,p.32.---------------- With this Act,only the gasoline portion of energy is figured into MPG calculation,for a mixed-energy type vehicle.------------------------------ here's how it might work with the VOLT: Let's say,you drive the VOLT hard on the highway for 25 miles,drawing the Li pack down to 80% discharge,then the gasoline engine kicks in,say for 9.5 additional miles.----------- The VOLT would have covered 34.5 miles and for CAFE purposes the government would only look at the gasoline used.If the VOLT gets 30-mpg on the HWY with the engine on,then it would have consumed 0.316 gallons of gas.------- If this amount happens to be 15% of the energy,then by dividing 34.5 miles by 0.15 yields 230-mpg.The plug-in electric power is completely discounted as if it didn't exist.------------------------------------- For a complete energy balance on the VOLT we could use their figure of 6.25kW per 25-miles.Dividing by battery efficiency,charger efficiency,transmission line efficiency,generating plant efficiency,yields 26.004 kW produced from heat energy.If provided by gasoline,this would require 0.797 gallons of gasoline burned at the power plant to create the 26kW.------------ Adding 0.797 + 0.316= 1.113 gallons per 34.5 miles for 31 mpg overall efficiency.[ for efficiencies,I used 80% @ battery,94% @ charger( Solectria ),94% @ grid,and 34% @ power plant ].------------------------ E-85 and M-85 cars would be allowed the same Arthur Anderson/Bernie Madoff - style cookin' the books and ledgerdemain to arrive at the Buck Rogers MPG numbers.

[cfg83]

aerohead -

Originally Posted by aerohead

...------------------------------------- For a complete energy balance on the VOLT we could use their figure of 6.25kW per 25-miles.Dividing by battery efficiency,charger efficiency,transmission line efficiency,generating plant efficiency,yields 26.004 kW produced from heat energy.If provided by gasoline,this would require 0.797 gallons of gasoline burned at the power plant to create the 26kW.------------ ...

I'm curious. Based on this assumption of line losses, what would the "energy balance MPG" be of the all-electric GM EV1? For example, how many kilowatts per 25-miles for the EV1 under the same driving cycle?

CarloSW2