GM-VOLT : Chevy Volt Electric Car Site

When GM announced the Chevy Volt should be rated at 230 MPG in city driving, they also divulged another efficiency rating.

Pure electric cars are generally rated in terms of kwh per 100 miles to show how efficient the vehilce is at using electrical energy. Since the Volt will drive the first 40 miles without gas it is appropriate to apply that metric to those miles.

Per GM’s press release, “applying EPA’s methodology, GM expects the Volt to consume as little as 25 kilowatt hours per 100 miles in city driving.” GM noted that this methodology is new and still under development in draft form.

Since we know the Volt will be able to use a maximum of 8 kwh of energy storage, then it could be concluded the Volt’s all electric range (AER) should come out only to 32 miles in city driving [100 mi/25 kwh x 8 kwh = 32 mi]. This is lower than the omnipresent 40 miles GM has stated since the beginning.

I sought clarification from Volt executive Frank Weber.

“The Volt is achieving 40 miles in the city and highway cycle, ” he said. “Nothing has changed.”

He noted however that in the new testing methodology “EPA is assuming a daily charge and is applying some real world factors that will degrade the EV range.”

“EPA has considered varying temperature and drive style conditions in their methodology,” explains Weber defining what he means by real world factors, and distinguishing how the new test differs from the old one.

“The cycle tests are run at a single temp and would not reflect range variation due to accessory loads,” said Weber referring to the older methodology from which the 40 mile designation was originally estimated.

I contacted Andrew Simpson, who is a Senior Research Fellow in plug-in vehicle technology at Curtin University, Australia, and previously worked at Tesla Motors and completed the EPA range certification testing of the Tesla Roadster. He said the older method is called “the SAE Recommended Practice J1634 “Electric Vehicle Energy Consumption and Range Test Procedure”. However, he notes “the standard is a bit outdated and SAE have formed a committee to revise it.” It is this committee that has written the draft.

“The revised 1634 procedure is an abbreviated version of the previous and consists of a battery capacity/characterization test followed by an finite number of drive cycles to measure energy consumption and estimate range,” said Vineet Mehta also of Tesla Motors.

The original J1634 procedure was written in 1993 and technically discontinued in 2003. The revised SAE J1634 draft is expected to be completed by December 2009.

So will the Volt still get 40 miles under real world standard conditions in the city? And what will the number be on the highway? These facts as well as the Volt’s MPG in generator node remain undisclosed.

It is important realize that EV ranges will vary considerably from what the manufacturer claims just as MPG does, and depend considerably on driving aggressiveness and use of accessory loads.

The sticker shown above was for the original EV-1 showing how the car got 30 kwh/100 miles in the city and a 20% more efficient 25 kwh/100 miles on the highway.

Yesterday was the highest traffic day in the history of GM-Volt.com, with over 60,000 visitors, and I apologize for the slowness of the site.

Why was this? Of course because GM announced that the Volt would get an EPA rating of more than 230 MPG. As exciting and compelling as that number is, it has raised as many questions as answers.

GM has not enunciated in exact detail how that number was arrived at.

But, while at the GM event I had the chance to get the answer from Larry Nitz, GM’s executive director of hybrid powertrain engineering

Can you explain how GM and the EPA arrived at the 230 MPG city estimate for the Volt?

In a conventional car there is two things that cause your efficiency to vary. The speed and intensity of your driving, and the environment; do you need HVAC, lights, etc.

With the Volt, you add two more things that makes your mileage vary, how far you drive, and how many times you plug in during the day.

So on any given day if you have plugged in your EV, range at low intensity driving, like the EPA city cycle is, is 40 miles. If you drive more aggressively your EV distance will be reduced.

Now, after you’ve depleted the battery, in the case of the Volt, the engine will start and the engine will keep the vehicle running for as long as you have fuel in the tank, and the fuel economy you have there matters too.

So in the calculation of the label, for that 230 you take into account the EV distance, the fuel economy after you depleted the charge, and the EPA used a traffic survey that was done in 2001 to create a composite.

They looked an an aggregate sample of the population and how far they drove in a day.

With the data we have and the data we shared with the EPA, from that value, they’ve created what’s called a utility factor.

It was a snapshot in time and based on this dataset we will weight the value on an aggregated probabilistic way what the value of the EV distance is, and we’ll also weight one minus that for the charge sustaining distance.

You go through this calculation that accounts for the fuel use and you come out with a number and the number is 230.

That’s a big number and you ask, will I ever get that number?, and its kind of interesting. In a normal car if you drive it high intensity you can never get the EPA , but in the Volt you always could, it just depends how far you have to drive. If you drive under the EV distance its infinite.

What was the percentage of time or miles in EV mode that was used?

The number was calculated by the EPA using this probabilistic curve and it had the statistics of the population in it.

How about the petroleum equivalence factor (PEF), is that included?
There will be on the label itself an accounting for the gasoline equivalent of KWH used. That’s a separate conversion that will get melded in another way and is not included in the MPG estimate.

So in summary, Nitz explains that the average Volt driver charging his car nightly can expect to burn one gallon of gas for every 230 miles traveled over time based on the behavior of a particular random population that was studied in 2001.

The highway calculation will be lower but the composite average is expected to be greater than 100 MPG.

The EPA has not confirmed this number yet because they haven’t tested the car, but they agreed to the testing method and GM is confident these are the numbers that will eventually become official.

GM CEO Fritz Henderson announced today that the Chevrolet Volt extended range electric car has been given an official EPA rating of more than 230 MPG city and a combined city/highway average fuel economy of more than 100 MPG.

The photo above is the first ever of the production Volt charger.

Henderson mentioned that GM has been quietly promoting the numbers 2 and 2 with a happy outlet and today owned up to it.

He said the EPA has developed a new federal fuel economy methodology draft for PHEVs.

Using this technique, the Volt will become the first mass produced vehicle to obtain a triple digit MPG rating. He also noted using this system the Volt is determined to have an efficiency of 25 kwh/100 miles. Considering the cost of electricity this amounts to 3 cents per mile.

“From the data we’ve seen, many Chevy Volt drivers may be able to be in pure electric mode on a daily basis without having to use any gas,” said GM Chief Executive Officer Fritz Henderson. “EPA labels are a yardstick for customers to compare the fuel efficiency of vehicles. So, a vehicle like the Volt that achieves a composite triple-digit fuel economy is a game-changer.”

The methodology assumes in city driving the car will mostly operate on electricity but some degree of gas operation is taken into account. The petroleum equivalence of electricity and a utility factor weighing in the population’s driving behavior are also included in the calculation.

Press Release:

Chevrolet Volt Expects 230 mpg in City Driving

* First mass-produced vehicle to claim more than 100 mpg composite fuel economy
* Tentative EPA methodology results show 25 kilowatt hours/100 miles electrical efficiency in city cycle
* Plugging in daily is key to high-mileage performance

WARREN, Mich. – The Chevrolet Volt extended-range electric vehicle is expected to achieve city fuel economy of at least 230 miles per gallon, based on development testing using a draft EPA federal fuel economy methodology for labeling for plug-in electric vehicles.

The Volt, which is scheduled to start production in late 2010 as a 2011 model, is expected to travel up to 40 miles on electricity from a single battery charge and be able to extend its overall range to more than 300 miles with its flex fuel-powered engine-generator.

“From the data we’ve seen, many Chevy Volt drivers may be able to be in pure electric mode on a daily basis without having to use any gas,” said GM Chief Executive Officer Fritz Henderson. “EPA labels are a yardstick for customers to compare the fuel efficiency of vehicles. So, a vehicle like the Volt that achieves a composite triple-digit fuel economy is a game-changer.”

According to U.S. Department of Transportation data, nearly eight of 10 Americans commute fewer than 40 miles a day http://tinyurl.com/U-S-DOTStudy .

“The key to high-mileage performance is for a Volt driver to plug into the electric grid at least once each day,” Henderson said.

Volt drivers’ actual gas-free mileage will vary depending on how far they travel and other factors, such as how much cargo or how many passengers they carry and how much the air conditioner or other accessories are used. Based on the results of unofficial development testing of pre-production prototypes, the Volt has achieved 40 miles of electric-only, petroleum-free driving in both EPA city and highway test cycles.

Under the new methodology being developed, EPA weights plug-in electric vehicles as traveling more city miles than highway miles on only electricity. The EPA methodology uses kilowatt hours per 100 miles traveled to define the electrical efficiency of plug-ins. Applying EPA’s methodology, GM expects the Volt to consume as little as 25 kilowatt hours per 100 miles in city driving. At the U.S. average cost of electricity (approximately 11 cents per kWh), a typical Volt driver would pay about $2.75 for electricity to travel 100 miles, or less than 3 cents per mile.

The Chevrolet Volt uses grid electricity as its primary source of energy to propel the car. There are two modes of operation: Electric and Extended-Range. In electric mode, the Volt will not use gasoline or produce tailpipe emissions when driving. During this primary mode of operation, the Volt is powered by electrical energy stored in its 16 kWh lithium-ion battery pack.

When the battery reaches a minimum state of charge, the Volt automatically switches to Extended-Range mode. In this secondary mode of operation, an engine-generator produces electricity to power the vehicle. The energy stored in the battery supplements the engine-generator when additional power is needed during heavy accelerations or on steep inclines.

“The 230 city mpg number is a great indication of the capabilities of the Volt’s electric propulsion system and its ability to displace gasoline,” said Frank Weber, global vehicle line executive for the Volt. “Actual testing with production vehicles will occur next year closer to vehicle launch. However, we are very encouraged by this development, and we also think that it is important to continue to share our findings in real time, as we have with other aspects of the Volt’s development.”

We recently learned GM will be moving its 2-mode plug-in hybrid drivetrain into a yet-unseen, yet-unnamed Buick compact crossover.

It has been noted that though the standard version of this car will come with a DI 4 cylinder engine capable of more than 30 MPG highway, the plugin version will not.

It will have a direct injection 3.5 L, 6 cylinder engine.

This is the same as the non-plugin 2-mode VUE was to have, though the car was never released. It was engineered for performance, doing 0 to 60 in 7 seconds, developing 270 HP and capable of towing 3500 pounds. The configuration would have achieved about 28 MPG city| 31 MPG highway.

With the addition of the 8 kwh rechargeable lithium-ion pack, GM claims the plugin vehicle can travel up to 10 miles pure EV at “low speeds”, and will deliver double the average fuel economy on the standard EPA cycles. This could amount to about 60 MPG.

Of course, it is logical to think if GM used a more efficient 4 cylinder gas engine and lowered the performance specs, even greater fuel efficiency could be achieved. I asked GM spokesperson Brian Corbett why this was not considered.

Here is his response:

Our hybrid strategy has been pretty consistent over the last few years.

Our GM Hybrid system — the mild hybrid, belt-alternator starter technology — is our affordable hybrid technology paired with smaller displacement engines. Our 2-mode hybrid system is our more capable, premium hybrid technology. It’s goal is to provide significantly higher fuel economy while maintaining the capability of the non-hybrid vehicle’s cargo carrying, towing, etc.

That strategy applies to the plug-in as well; maintaining the capability of a 5-passenger crossover while providing significant improvements in fuel economy. It provides E85 capability, which means it likely will be the first flex-fuel hybrid.

I responded to Brian that I thought anyone looking for plug-in would be looking for fuel economy, that they would like the crossover style but wouldn’t care as much about a powerful motor. I suspected that those individuals would rather get 20% more fuel efficiency in exchange for 20% less acceleration and power.

He replied:

That is probably true for plug-in “enthusiasts” or “early adopters.” But I think the feeling is we’ve got try and get the mainstream public interested in plug-in technology in order to make a meaningful different when it comes to reducing emissions and diversifying from petroleum.

So it seems whether or not most people interested in significantly improving their fuel economy are willing downsize to a 4-cylinder is debatable, especially when it comes to though who desire a crossover.

What do you think?

A mysterious viral advertising campaign has surfaced on television and the Internet this week, which has been further amplified over the blogosphere.  In fact, flickr, facebook , YouTube, and blog sites have surface around it.

A simple green background shows the number 230, with a winking electric outlet instead of the zero. Below is the date 8-11.

AdAge determined that the source of the campaign is none other than GM, but the automaker and its ad agencies won’t say what it means.

Speculation has varied on its meaning from the MPG of the Buick plug-in to the MPG of the Volt or even something to do with charging at 220V.

GM is holding a press conference in Detroit on August 11th, and yes I will be there.

Reports quote sources as saying the number will be the Volt’s official MPG rating, but how they came to it remains a mystery; highway, city, average, none of the above?  And if so how was it calculated?  The EPA city cycle is 11.04 miles, the highway cycle is 10.26 miles.  The car goes 40 mile without any gas, and 78% of drivers drive less than 40 miles per day (utility factor).  Do your own math.

Here’s my guess:

I heard of a method to determine the MPG of an EREV; first the car is driven from a full battery until it reaches charge-sustaining mode, then one more cycle is driven. If we use the highway schedule, the first 40 miles are electric.  One more cycle is 11 more miles. If the Volt gets 50 MPG in charge sustaining mode, it will use .22 gallons of gas for that 11 miles.  Thus 51 miles/.22 gallons = 231.8 MPG.

We can have fun guessing for now, but be sure to logon to GM-Volt.com on Tuesday morning and we will have the answer as soon as it hits.

Plus, if you have any questions you want me to ask the Volt team and execs while I am there, leave them in the comments.

Source (AdAge)

[UPDATE:  The method referred to to measure the efficiency of an EREV is far more complex and still under development.  Though my calculation came out similar the methodology GM actually used to determine the MPG was different.  See this post.]

On Friday, GM announced that it had chosen an Orion Township Michigan assembly plant as the location it would build a new upcoming subcompact car.  Stamping for the car would be done in Pontiac Michigan.  The move takes this future vehilce away from China where it was originally planned to be built.  The move stateside was a concession to the UAW for its agreement to exchange its debt for equity.  67% of GM’s vehicles are built in the states, and shipping one from China adds $850 to its cost.

“Small cars represent one of the fastest-growing segments in both the U.S. and around the world,” said Troy Clarke, president of General Motors North America. “ GM will be the only automaker, foreign or domestic, to build small cars in the U.S . , and we believe Orion Assembly and Pontiac Stamping are well suited to deliver a high-quality, fuel-efficient car that competes with anything in the marketplace.”

Clark said the new subcompact also known as a B-class vehicle would not be the Chevrolet Spark that most had speculated, calling it instead, “a yet-to-be announced product.”  The current Aveo which is slated to be discontinued is GM’s current B-class car. Some speculate the Chevy Viva will be the new car.

“We’re thinking the B-car will sell north of 100,000 vehicles,” said Clarke, though he acknowledged only about 40,000 Aveos are sold yearly now. “We’re thinking this segment will grow because of higher fuel prices as well as the attractiveness and utility of the vehicle.”

There are no indications the car will be a hybrid though GM says the car “will add to the automaker’s growing portfolio of U.S.-built, highly fuel-efficient cars, including the Chevrolet Cruze and Volt.”

Production will begin in 2011 and 1400 jobs will be restored by this plan.

Source (GM)