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2011 Chevy Volt
But Volt's true nature may actually be an improvement, plus early reviews are complementary

In the week when auto editors turned in their first reviews of test drives of General Motors' upcoming 2011 Chevy Volt, there's been a bizarre twist that's largely overshadowed these initial impressions.

In a wild twist, Larry Nitz, GM's executive director of electric and hybrid powertrain engineering, has revealed that the gasoline engine actually will drive the Volt mechanically.

Previously, GM had maintained that the Volt was a battery electric vehicle (BEV).  When the battery's 40-mile range (since revised to "25 to 50 miles") was nearing exhaustion, a turbocharged 1.0-liter 3-cylinder gasoline engine kicked in, supply electrical current directly to the batteries and motor to provide more than 200 extra miles in range.

That platform was known as "E-Flex".  But unbeknownst to anyone, GM was pulling a bait and switch.

Today, Mr. Nitz revealed that 
actual powertrain.  The Volt, it turns out, is not a BEV like the 2011 Nissan Leaf.  It is actually a plug-in hybrid electric vehicle (PHEV) like the 2012 Ford Focus or 2012 Toyota Prius EV.

The internal combustion engine (ICE) -- now a 1.4L 84 hp 4-cylinder design -- and the 149 hp permanent-magnet AC electric motor both feed into a planetary gear set and three electronically controlled, hydraulically activated multi-plate clutches.  The resulting automatic transmission is marvel of electro-mechanical engineering offering a blend of efficiency and power.  The entire powertrain is bolted together to minimize noise, vibration, and harshness (NVH) and reduce space usage.

Arguably this advanced transmission is much better for customers than what GM initially 
said it was offering.  As Ford Motor Company pointed out in our recent interview with their head of electrification, BEVs suffer from poor performance in cold or hot weather, as the battery's performance deteriorates sharply. 

So why the bizarre farce on GM's part in claiming its BEV was really a PHEV, when the actual design would be more beneficial to the majority of customers?  Mr. Nitz claims that GM had to deceive the public in order to secure its patents on its unique transmission.  Now with the patents in hand, he was free to go public with the new powertrain platform, dubbed "Voltec", he says.

Turning to what GM had intended to be the focus this week, 
MotorTrend and The Detroit News have taken their first drives in the upcoming PHEV and are quite enthusiastic.

The Detroit News writes:

After I drove more than 32 miles on electric power only — in a very un-eco-friendly manner — the Volt’s little engine began powering the car. This was the moment I had been waiting for: It’s one thing to power a car with batteries, but it’s revolutionary to have a gas engine supply the power to electric motors.
The succession of power is more seamless than a presidential election. The engine is quiet and keeps humming along. There’s never a glitch, a pause or a moment when the engine noticeably kicks on or off. For the most part, once the initial battery charge is drained, the engine produces the electric power to drive the motor. 
...

Most of all, there's nothing to adjust to in the Volt. My 75-mile trip used a total of 0.9 gallons of gasoline. But I would have been happy to drive farther. 

And MotorTrend opines:

The Volt is no sports car, but it blows Toyota's plug-in Prius away (9.8 seconds to 60 mph), and runs neck and neck with a 2.4-liter Malibu in acceleration and handling tests. Figure-eight performance is virtually identical at 28.4 seconds and 0.59 g, and the Volt's 119-foot stops from 60 mph are just 3 feet longer-impressive, given its 226-pound weight disadvantage and low-rolling-resistance tires. (The Prius weighs 376 pounds less than the Volt, yet it just matches its 0.78g lateral grip, trails both Chevys by 0.4 second on the figure eight, and needs 131 feet to stop from 60 mph.)

Based on these reports it appears that GM's "surprise" of the ICE hooking up directly to the transmission to drive the wheels seems indeed to be a good one.  On the other hand, many will likely dwell on the fact that GM pulled a bait-and-switch on the customer.  

After all, some customers really want an honest-to-goodness BEV and may now being a bit bummed that they instead ordered what essentially amounts to a souped up plug-in hybrid.  Others have been vocal critics of the vehicle (and GM in general) and will likely jump on GM's deception as a platform to attack the vehicle (and GM in general).

Perhaps GM was right -- they had to mislead the public to protect their intellectual property.  But the move was certainly a very bad decision in terms of public relations.  GM can only hope that the public settles down and comes to realize the bottom line -- that it's offering them a superior package than what it initially promised to deliver.



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Either way
By Sazabi19 on 10/11/2010 2:23:28 PM , Rating: 5
there was going to be a ICE running at one point or another once the battery was drained... so is it really that big of a deal? Sure it wasn't nice to decieve us but it really isn't that much different. Am i wrong in my thinking here?




RE: Either way
By chromal on 10/11/2010 2:50:02 PM , Rating: 2
Well, the original design GM was touting was that the engine would serve the role of an APU (Auxillary Power Unit) as opposed to direct locomotive force. The idea there was that they would have more flexibility, e.g.: 3-cyl turbo APU? fuel cell APU? turbine APU? extra battery alternative to APU? No problem, they all work interchangeably. This is an old idea applied to automotive technology, which would have been revolutionary.

Here, with what GM's *actually* going to be doing, we're looking at a heavy and expensive Prius rehash with Detroit-designed/built reliability/efficiency/resale value... which I don't perceive as very reassuring. On the bright side, it will make the MPG numbers a more meaningful comparison with other hybrids, I guess, but we're no closer to some of the exciting possibilities GM that strip-teased the world with.


RE: Either way
By dubldwn on 10/11/2010 3:39:18 PM , Rating: 1
quote:
Am i wrong in my thinking here?

Yes. This is a big deal. The power train GM described was a true EV that we could envision improving over time with smaller, more powerful batteries and lighter, more efficient engines to generate electricity (or different engines all together, as the poster above alluded to, operating at maximum efficiency). This is now just a Prius of Fusion with a huge (and expensive) battery.


RE: Either way
By foolsgambit11 on 10/11/2010 3:58:40 PM , Rating: 4
The maximum efficiency part is the key to the difference. An electric motor runs near maximum efficiency at all points along its power curve, so it is the most efficient propulsion mechanism available (practically speaking). An ICE only runs at peak efficiency at one point along its power curve; all other output levels are, essentially, wasting gas. So tune an ICE for high efficiency at one point on its curve, and send that power to a storage medium (batteries), so it can be drawn on by the electric motor, and you have the best efficiency possible for an automobile with current tech.

(A note on batteries - they generally are less efficient when drained at higher speeds. They aren't like a reservoir in that sense - the faster you drain the power out, the less total power you can get from the battery. This complicates the total system efficiency calculations, but ultimately, serial hybrids should still come out ahead. Now back on subject....)

With the new layout, the engine is probably de-tuned to have a lower peak efficiency but greater efficiency over a range so it can effectively power the transmission. Plus, the transmission has become more complicated, increasing power losses there. From a reaching-for-perfection standpoint, these are disappointments, but I can understand there was likely some good logic to it. By coupling the ICE to the transmission, you reduce the total HP of all components necessary for a given level of performance, thereby reducing manufacturing costs, at the expense of lower fuel economy. It's all a trade-off.


RE: Either way
By clovell on 10/11/2010 5:05:58 PM , Rating: 2
Big difference in durability & maintenance costs & moving parts. This is the entire crux of Serial vs. Parallel hybrid automotive design.


RE: Either way
By Reclaimer77 on 10/11/2010 8:38:35 PM , Rating: 2
quote:
Am i wrong in my thinking here?


YES


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