Volt nothing more than a lame hybrid

[Elie]

http://www.engadget.com/tag/generalmotors

Chevy says Volt's gas engine can power the wheels, it's just a hybrid after all

Sheesh!

[Dr Mordrid]

They refer to gm-volt.com, not a GM site but a fan-site with inside info, but didn't quite get it right: it's not "just a hybrid" as the "controversial" mode isn't the most commonly used one.

The key components are the 111 kw electric motor, the 55 kw electric motor/generator, and the 62 kw 1.4 L gasoline engine. Voltec has 4 drive states, only 3 of which have been previously discussed.

1. EV - the battery drives the 111 kw electric motor. Real-world road tests now show a range of 25 (uphill or racing) to 50+ miles. One reviewer said with efficiency driving on level terrain (Michigan) he came close to 58 miles.

2. EV at >70mph - the 55 kw motor/generator kicks in, as an electric motor, to make up for high RPM losses in the 111 kw motor. At this time the recharging engine is decoupled. This adds at least 2 miles of EV range.

3. Range Extender - when the battery reaches a 20% - 25% SOC (state of charge) the 4 cyl kicks in and the 55 kw becomes a generator. Its output then powers the car, buffering through the battery.

All as advertised since day-one. Now for the newbie - Mode 4

4. Range Extender >70 mph - this is where the controversy comes into play. It's not been discussed for intellectual property reasons - it's the subject of a patent that was recently awarded. Simply put: a small part of the the 4 cyls output is mechanically coupled through the 55 kw motor/generator while the generator continues to power the 111 kw through the battery buffer. Â*Still; the vast majority of the power to the wheels is electric.Â*The gain is 10% - 15% in efficiency at high speeds.

I guess GM could have left Mode 4 out to mollify the boo-birds & purists, but instead they added it to boost highway mileage.

Which way would you have it?

[Dr Mordrid]

Summing up:

Can the Volt run as an EV? YES

Can Volt keep going after you use up the charge? YES

Can the 4 cyl provide a bit of power to increase efficiency, and then only at >70 mph (above most state speed limits anyhow)? YES

Who cares about Mode 4, in a negative way? Not me.

[VJ]

As far as I can tell, mode 4 contradicts statements they previously made; and this is the problem.

Ok if this is for intellectual property reasons, but it is a shame that this might put the car in a more negative perspective. IMO, it doesn't really matter how it achieves things; if it has good performance (fuel economy, ...) that should be all that matters. Now I hope it won't get undesesrved negative publicity.

[DukeP]

Problem for me:
Difference between 130% tax - or none.
(Yeah, cars ar taxed about 180% in Denmark - pure electrics, as defined on the motering -is exempt from the base 130% tax and only has to pay the vat of 25%).

Looks like its a Tessla for me.

~~DukeP~~

[Mehen]

Bah, Tesla... get an Audi E-Tron or Citroen Survolt

[Dr Mordrid]

More competitors for Tesla, not Volt, and at 48 and 31 kWh respectively you get a $20k battery with a long charge time and fixed range - no long trips. Charge time would run a day+ instead of a few hours for Voltec vehicles and no range extender for when there's no plug.

[Wulfman]

Nnearly every house here has a 380V connection for some electrical appliances, these should easily charge even a 48 kWh battery over night.

I also agree regarding the misleading information so far - the argument has always been that a mechanical connection between the (fuel) engine and the wheels adds weight and complexity to a hybrid, and reduces efficiency and flexibility. What sort of transmission are they going to use, how big / heavy is it going to be?
I could easily find a couple of posts on the topic, always trash-talking the Prius for being a non-serial hybrid, a poor substitute for the real thing - and then the Volt turns out to be (by definition) a non-serial hybrid as well?

mfg
wulfman

[Dr Mordrid]

And if it's serial for 90+% of driving, and (maybe) not for <10% when that changeover is for efficiency does that justify all this fuss?

Saw a service training DVD other day showing an animation of the mode changes, and to be honest about it this mechanical "linkage" seems more to provide power for synching/linking the two electric motor outputs than driving the wheels in a significant way.

[Wulfman]

You still have to lug the stuff around 100% of the time, don't you? I'm just wondering - if you just need it 10% of the time, and if it is doing hardly anything at all, why bother?

mfg
wulfman

[Mehen]

Get the Nissan Leaf then. Pure electric, reasonably priced, 100 mile range.

[Dr Mordrid]

EV's have a range limited by the motor draw vs. how many kWh are in the battery. If you run low and don't have the range remaining to get home then it's time to find a charging station and a hotel. EREV's have a small motor that lets you keep driving on fuel 'til you can get home. It also allows you to use a smaller, and therefore thousands of $$ cheaper, battery.

Once we have cheaper, lightweight 75-100 kWh batteries/ultracaps that can charge in a few minutes then EREV won't be necessary for daily use EV's, but for now it's the most practical way to get an EV range >than the daily average of 37 mi/day and still be able to run further when necessary.

BTW: that is a lightweight motor with few of the usual addons, so it doesn't add as much mass as most people think.

[Wulfman]

so you are now carefully avoiding the word "serial hybrid"?

mfg
wulfman