Edmunds: "GM lied" about the Volt's electric drive system

[sportyaccordy]

This simply points out the problem of comparing electrric vehicles to gas and diesel powered vehicles.   There need to be consensus on an energy unit that is applicable to both.  Perhaps BTU, since the btu's required to generate the electricity that charges the Volt at home can be compared to the BTU content of the fuel in a regular vehicle.

I did this calc before a while ago, I forget the details but overall it didn't pay off

[Mustangfan2003]

http://www.youtube.com/watch?v=1P-9wXTbAs8

[AutobahnSHO]

I'm about halfway into Top Gear season 11 on Netflix.

They ran a new Prius 10 laps around their test track as fast as it would go (handling= teh suX). An M3 followed, for a boring ride.
The BMW got twice the gas mileage for that exercise.

[Mustangfan2003]

M3>Prius. 

[Colonel Cadillac]

The Prius doesn't "pay off" but has sold incredibly well? Explain this to me...

Does the equation miss the non-cash components, rendering it inaccurate? 

[Laconian]

I'm about halfway into Top Gear season 11 on Netflix.

They ran a new Prius 10 laps around their test track as fast as it would go (handling= teh suX). An M3 followed, for a boring ride.
The BMW got twice the gas mileage for that exercise.

Well, duh, the Prius motor was being stressed and the BMW was barely breaking a sweat. Small engines waste fuel under heavy loads, just like every other motor.

[Vinsanity]

Well, duh, the Prius motor was being stressed and the BMW was barely breaking a sweat. Small engines waste fuel under heavy loads, just like every other motor.

tell that to Wimmer next time he tries to crack a joke about Americans and our eleventy billion hp motors.

[ChrisV]

That's what the article said.  "However, under certain circumstances — speeds near or above 70 mph — the engine will directly drive the front wheels in conjunction with the electric motors.""

Does this mean the electric motors don't have the capacity to handle speeds above 70?  Or above those speeds the battery is drained too quickly if it's the sole provider of motive force? 

it says:

"when going above 70 mph in charge sustaining mode" i.e. when the generator is on, not when the batteries are charged. So if the batteries are charged and it['s running on pure electricity, the gas engine is NOT helping it get from 70-100 mph. It only does so after the batteries are depleted.

[giant_mtb]

One thing I've wondered about is why they use such large engines simply as generators.  Wouldn't a much smaller engine suffice as a generator to charge the batteries?  A 3-cylinder?  A 250-cc 4-stroke generating 1,000 watts? 

[Vinsanity]

One thing I've wondered about is why they use such large engines simply as generators.  Wouldn't a much smaller engine suffice as a generator to charge the batteries?  A 3-cylinder?  A 250-cc 4-stroke generating 1,000 watts? 

I'm guessing it's because the smaller generator would need to run harder to provide the same charge to the battery? Lesser amount of NVH and whatever...

[giant_mtb]

I'm guessing it's because the smaller generator would need to run harder to provide the same charge to the battery? Lesser amount of NVH and whatever...

That is probably true, but a 1.4L 4-cyl. Ecotec seems like a bit of overkill when its "sole" purpose is to spin a friggin' reverse electric motor.  An engine that can provide propulsion for an entire vehicle does not need to be used to simply spin a shaft.

[93JC]

It's generating a lot of electricity. It's all fine and dandy to say "Just put a two-cylinder turbodiesel in there!" but it needs a lot of power to generate that electricity.

Plus the 1.4 L engine is shared with other GM vehicles, which makes this a hell of a lot cheaper than designing some rinky-dink special-purpose engine.

[giant_mtb]

Just how much electricity does it need, though?  And when the engine is running, is it only putting power to the batteries or is its generator directly connected to the drive motor as well?

[r0tor]

Just how much electricity does it need, though?  And when the engine is running, is it only putting power to the batteries or is its generator directly connected to the drive motor as well?

Well, a 100 HP electric motor is going to need a generator a bit more then 100hp to keep running....

[giant_mtb]

Well, a 100 HP electric motor is going to need a generator a bit more then 100hp to keep running....

No way!

Is that the power of the Volt's electric motor?

[2o6]

Well, a 100 HP electric motor is going to need a generator a bit more then 100hp to keep running....

The Volt's generator is only 70HP.

[giant_mtb]

The Volt's electric motor is 149HP. Its generator is 74HP. And its 1.4L 4-cyl. generates how much power?  Is it detuned?

[2o6]

The Volt's electric motor is 149HP. Its generator is 74HP. And its 1.4L 4-cyl. generates how much power?  Is it detuned?

It's tuned for only a certain range of output, and it's also the Cruze's 1.4T without the turbo.

[giant_mtb]

Seems like a 1.4L 4-cyl. producing 80HP is a bit of a...waste.  But, whatevs.

[Vinsanity]

Seems like a 1.4L 4-cyl. producing 80HP is a bit of a...waste.  But, whatevs.

Atkinson cycle, perhaps? I know those engines produce less hp in favor of greater efficiency

[AutobahnSHO]

Generator hp is totally different than car hp.

Car hp has to go to different revs, the generator is on a fixed output.

[giant_mtb]

[2o6]

Atkinson cycle, perhaps? I know those engines produce less hp in favor of greater efficiency

Nope. Otto Cycle.

[the Teuton]

Does anyone else think a diesel generator would have made more sense for the Volt?

[giant_mtb]

Does anyone else think a diesel generator would have made more sense for the Volt?

\o

[AutobahnSHO]

Does anyone else think a diesel generator would have made more sense for the Volt?

I do. But 299,999,999 other Americans probably would freak out at DIESEL!>!>!!! ! ! ! 111!!1!!!!!!!!!!!!!!!!!!!!!!!!

[2o6]

I do. But 299,999,999 other Americans probably would freak out at DIESEL!>!>!!! ! ! ! 111!!1!!!!!!!!!!!!!!!!!!!!!!!!

The Volt is already quite expensive due to the battery and hybrid technology. Bringing a Diesel into the question only drives the price up more. GM doesn't make a Diesel motor small enough (New GM Diesels are now Fiat JTD motors, or motors from VM Motori) and not only that but since those small diesels aren't sold in ANY car in the US (Neither Fiat or VM Motori have any engines in any cars sold in the US) they have to pass regulations, not to mention the cost for repairs and such.

[giant_mtb]

Hybrids should have used diesel engines since day one, IMO.  Greater efficiency on both sides.  But, like SHO said, Americans think all diesels sound like semi-trucks.

[GoCougs]

Why diesels are not used in hybrids:

1.) Cost. Diesel engines cost more than their gasoline counterparts in these emissions-regulative times but also on a $/hp basis owing for the need for F/I.

2.) Durability. Diesel engines are much harder to start so the starter motor and related hardware would be much more robust. Plus, with the auto-start cycle coming into vogue diesels are incapable of doing so without additional hardware.

3.) Emissions. The goal of a hybrid is to reduce emissions, and "clean" diesels are still pretty bad.

4.) Weight. Diesel engines typically weigh more per unit of power owing to the stronger block needed for the much higher compression ratios.

5.) NVH+smell. Diesels still noticeable lag their gasoline counterparts.