Journalist experiences Volt's electric-to-hybrid transition, says it needs improvement

There is no reason the system could not switch in an instant as soon as the brakes were pressed.

The expense and weight of a bigger electric motor is not too big but unfortunately making the battery/electronic system able to put out more power to run it is much harder. Tesla has mastered that but at a cost.

 

From the way the articles are written, the word "engage" makes me think of a clutch like system if it was any different (set up like toyota's HSD) why not stated it simply will reverse. That's why I say I need a diagram of the set up or it needs to be clarified.

I know half of the expense of the Tesla Roadster's motors are because it soley works on ac. I remember the Volt has dc motors

 

The key word is energy storage system. Hydrogen, Gasoline, Diesel or Battery are examples. Electric motor does not store power.

FCHV has energy stored in hydrogen and battery. Prius and Volt has energy stored in gasoline and battery. Tesla roadster only store energy in the battery therefore it not a hybrid; a pure EV.

Diesel with WVO is not a hybrid. It would be as silly to claim any car that runs on gasoline with E10 (10% ethanol) is a hybrid.

When did the Volt become the standard on EV range? I think 40 miles is too much simply due to the current cost of battery.

40 miles would cover 75% of American commute. That was based on a study done about 15 years ago. Today's cities are more congested ever. It is wise for Toyota to make a PHV and do their own research before deciding on the range. For GM, it is the other way around.

The percentage does not scale linear with the range. I would say 65% of American have 20 miles range. 13 miles may cover 50% trips. Take them as a grain of salt as those are just numbers I made up to make a point about not scaling in linear.

Here it is. Engineering Design of the Chevy Volt’s Two Electric Motors

 

There are no clutches in the Volt, Tesla (current version) or Prius. The Volt's drivetrain is an electric motor connected to the wheels. Like the Prius there are friction brakes as well as regenerative breaking.

The Volt, Tesla and Prius all us AC motors. Modern electronics allow for cheaper and more reliable AC motors.

 

Hampdenwireless,

Please the link I posted above. We are talking about the generator engaging and act as a motor.

 

Could the GM engineer have been any vaguer, or was he trying to be confusing?

I don't have the knowledge to comment on how, or when, having the generator work as a motor would be better than just using the main traction motor. Does the generator motor decouple from the engine when coupled to the traction motor? The beauty of serial plug-in is the same has the Prius's HSD, the mechanical simplicity. I'm losing faith that GM will not muck it up somehow.

Yeah, it is a bit silly, that was my point. Let's consider Mazada's hydrogen/gasoline RX-8. Being in different states, it is impossible to fuel systems than for the fuel they are intended for, unlike the greaser diesel, and it can't argued the fuels are close enough together to be considered the energy storage system. Going by the original quote on official hybrid designation, which I did admit may be out of context, it is a hybrid.
Would you consider it a hybrid?
If not, how is a FCV, one? I haven't heard of one being plug-in also.

 

Here's my understanding of this gobbledegook..... The "traction motor" acts as a motor when driving the wheels w/ power from the batteries and acts as a generator when used for regenerative braking. The "generator" acts as a motor when starting the engine and acts as a generator when sending power to the batteries.

The "possibility" is that they may be thinking of having a direct ELECTRICAL (no mechanical) connection between the two (ie. semi-synchronous ???) and avoiding the charge/discharge and switching losses when using them in that state.

 

That's what I was thinking, but the engineer or writer had really butchered message if so.

 

Well the next unexplainable choice by the Volt Engineers is the choice to run the ICE on the OTTO cycle than on an atkinson cycle (which most hybrid use). it's over at gm-volt.com. Atkinson cycle engines run best at constant rpms with the best fuel economy. What is GM thinking?!?

 

I think their priority is to rush it out and fix/optimize it later. Typical...

 

I read some of the comments over at gm volt and having an off the shelf engine does not prevent it from using the Atkinson cycle.... Nissan uses the same engine (2.5 4cylinder) in both its Hybrid and non hybrid model. In the hybrid model the 2.5 is using the Atkinson cycle. Toyota and ford do the same with their hybrids (The camry and highlander hybrid for toyota)

I think the F.E. of the volt when the ICE is running isn't going to top 50mpg.

 

Tuning Atkinson engine for efficiency, noise and vibration is probably the real reason.

Remember, late in take valve adjustment can achieve very high compression / expansion ratio. Toyota has the highest (13:1) in Prius.

Honda IMA and 2-mode ICE are around 11 or 12. The higher the ratio, the more work you can get out per cycle -- higher efficiency.

 

I can't see that tuning an atkinson cycle engine to be that big of a deal... Lexus does it for the RX450h (which is one of the quietest engine under throttle I've heard). My opinion is if you are going to make it... make it right. If the Volt is going to have competition (like the PHEV Prius) there should be no corners cut. A ICE running an OTTO cycle is plainly not just efficient as an Atkinson cycle ICE. That's going to hurt the Volt once it goes into range extending mode.

I fear that the Volt and a PHEV Prius over a 200 mile journey (continuos) will have the same MPG. While the Prius will be priced significantly less. That would be a stumbling block for many people.

If the Volt does not trump the PHEV Prius significantly in range extended mode it is not going to far well. There are going to be two camps for EV's. The "I have range anxiety" and the "I don't have range anxiety".

If you are a part of I have range anxiety camp (because you do drive alot) you will look at the post EV range mpg and the OTTO cycle choice is going to hurt the Volt along with it's price. The PHEV Prius will probably be the better choice.

If you are a part of the I dont have camp, there are plenty of EV's on the way (like the Leaf) that have a larger EV range and larger interiors (five seaters). and the Leaf is looking to come in at cheaper than the Volt.

 

Nope. The Volt's Otto cycle ICE can not get 50 MPG in theory. There will be conversion loss. Thermal efficiency for Otto cycle is 15% less than Atkinson cycle. The reason is because the expansion and compression (E/C) stroke is the same in Otto cycle. Even HCCI will have the same E/C ratio.

Only a Direct Injection Atkinson cycle running HCCI can beat the spark ignite Atkinson cycle ICE.

 

I share the same opinion. But GM management....

Remember, Toyota has expertise in Atkinson cycle. The chief engineer that worked on the original Prius specialized in Atkinson cycle.

 

They've placed heavy expectations on performance, setting the bar well above middle-market. That forced them to use a larger engine not tuned for efficiency.

It would have been fascinating if they had switched to an even larger one that put heavy emphasis on efficiency. But then issues of heat managements (both extremes) becomes even more of a problem.

So currently, we're looking at about 40 MPG for CS-mode and drive experience that will be tuned better later on.
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Don't you think that is carving a niche market out of an already niche market? There are going to be plenty of high performance ev's by 2012.

My stance is GM should produce their volt (RE-EV) system to be the best at fuel economy during ev mode (ev range) and during CS mode. Now if people want a sportier Volt give them the Volt SS. If GM has proven that their system is best other Car Cos will want to license the tech and GM WILL make money that way. I understand that people want sporty, but that has not stopped the prius at all. Have the Volt debut with the regular Volt and a Volt SS. Many people who want sport aren't going to look at either the Prius or the Volt because they don't "look" sporty enough.

 

The 2010 Prius uses the pre-existing 2ZR block (1.8L Toyota Corolla, Matrix, Avensis). It wasn't built specifically for the Prius - which can be seen by the fact that the Prius engine it still has a pulley on the end of the crankshaft, where the serpentine accessory drive belt would normally go, to balance the masses.

The 1NZ engine block used for the first two-and-a-half generations was designed primarily for the Prius but was also designed to be usable in other cars. It has a hole for a starter motor which is unused on the Prius, so there's a blanking plate to keep debris out. On some cars it was assembled the wrong way round, which can cause wear to a wiring harness that rubs against a tab.

I would assume that there's still a starter-motor hole on the 2010 but I haven't seen anyone document it.