Prius Plug-in vs Chevy-Volt thoughts

11 miles (EPA PiP range on battery) is 17.7 km, not 21km.

The difference in ICE starting is 39km

Not sure what the 2.12 you are subtracting in your equation represents. If it is just what it took to make the red line cross where you want, then it needs to be adjusted to 2.4765 to cross at 39km and the revised equation yields
(4.7/100)*x= (6.35/100)*x - 2.4765 - Wolfram|Alpha

or 150km. Add in the 17km and it yields 167km or just over 103+ miles

 

I've seen this line of reasoning used before and it doesn't make a whole lot of sense. I guess I should drop my life insurance since I've never used it. <wink, wink>

I'm not crazy about the mini-spares but given the choice between that and nothing, I'll go with the mini. If it were me, I'd least get one for road trips as there should be plenty of them for cheap in junk yards.

 

That would portray the 11 as the point of depletion, when in reality even though EV may no longer be available plug-supplied electricity still is. That results in super-boosted MPG while the engine runs, not a switch to ordinary HV mode.

So, subtracting 11 as if it was all EV is realistic.

Cost & Weight are factors regardless. Being able to deliver something competitive in high-volume for a reasonable profit is very important.

Are you ever going to finally acknowledge the power of hype?

Whether or not they were right didn't matter. They were the ones stirring the market and influencing GM's next decisions.

We've seen that several times already, where the media distorts and exaggerates. Some simply don't care about facts. Heck, on the fan sites they'll just ban you, negative vote, or close the thread if something is said they don't like. It doesn't stop them.

Their influence is greater than you want to admit.
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Not sure if you are disagreeing or agreeing. So just to be clear, 11 miles (modulo EPA rounding) IS the point of depletion.

The SAE standard/EPA measurements for the first part of the PHEV MPGe computations is until the the end of CD mode, i.e. when the battery SOC reaches its HV steady state. Even if the car formally left EV mode at 6 miles.. the 11miles is when its grid-based energy was exhausted. After that it is regular HV mode. (Though it may do a little better overall in HV mode with bigger buffer as some Prius PHV owners have already shown regen was more limited with the regular Prius).

 

So the PiP does only 11 miles EV?
2.12 was calculated backwards from 35 miles (56km) it can do in EV (EPA sticker) and gasoline that would be consumed if it were running on gas. That's why the subtraction. Why did you increase that number?

 

yep. 11 miles is the CD range, see the EPA sticker here
http://img.tapatalk.com/c6e4dd63-44dc-89fa.jpg

As I said I was not sure what you were doing with your formulas. I guessed the 2.12 guessing that it was designed to set the zero point to 35km, or equivalently that you subtracted the EV range of the Volt and PiP. I increase it because the difference is now 39km (which is what one gets using 11 miles rather than 13 or something you used).

 

Not really conjured. As late as 2007 there was a rumor the Volt was getting a 1.1L Diesel and that was from a SAE magazine. Well not the engine, that was supposedly coming from Opel. Sorry couldn't resist. Wow I thought that would never be brought up again.

 

Really? Do you have a pointer? I followed the Volt (and reflex) pretty closely and I think I would have remembered if they talked diesel as I'd prefer that (could make my own biodiesel). Maybe you are thinking of the 1.0L from Opel (pat of the family 0 mentioned above) that was discussed. Just googled for a volt diesel and and could not find anything the 2006-2008 time frame like that.

 

You really want one because I just Googled and found one from July of 2007.

Could be the 1.0L but since they never used one even for their concept who cares?

 

:fish2:

 

This topic is probably better suited for personal opinions anyway. And I have my own reasons why I chose the PiP over the Volt.

 

Sorry if I came across agressive. I really was interested. I'm working (slowly) on an academic paper on PHEVs.. though really expect to stick to more scientific papers, but an SAE paper would be appropriate.

Well my googling only found things like this
Diesel Volt?
That make it seem there was no is no diesel volt.

Maybe there was a diesel ecoflex or maybe even a concept showing a diesel would work in a E-Flex (precursor name to Voltec) just as they showed they could do a hydrogen E-Flex.

I still find the diesel PHEV concept compelling as I'm quite willing to go make my own biodiesel and then could reduce petrol use (and carbon) even more.

 

You're right there probably was no Diesel Volt but the rumors were there back then way before the concept came out. But now there's rumors fresh again with talk of Diesel and, what other laugher did I hear/read, rotary engine. I guess what's old is new again. John and I have been on this board and others since 2004 and we probably have discussed this a lot (John, I think we discussed this on the other Prius site PriusOnline and there was a link there but I can't find it). Currently SAE has a guest company pushing a .8L range extender that's suppose to be completely modular so who knows what is possible. Personally I thought putting a high torque small diesel in the Volt would be the coolest thing and a world beater, but no way would it pass emission testing back then. But if Opel can do it to the Ampera maybe you can import it. Also if the "other" biofuel, butanol, is ever produced cheaply enough you may get your wish with the gasoline version of the Volt.

 

I recall reading an article that the Volt could have achieved 50MPG with a larger engine, but the smaller 1.4L engine was chosen instead. The official reason was that the 1.4L engine was quieter, but it seemed like the real reason was to cut cost.

The Capstone C30 has 25% electrical efficiency LHV b/c it does not include power cogeneration to capture all the energy converted to heat. If you look at the Capstone C65, it has a 62% system efficiency with heat recovery (and 29% for the electrical efficiency LHV).

A larger, more efficient Atkinson ICE could have had most of the parts shared with an Otto variant of the same ICE. This is what Toyota did with all three generations of Prius to save money by reusing parts, but choosing the optimum cycle for the hybrid.

My understanding is that air pumping losses is the main drag if the ICE is spun while not firing. Toyota's solution to this is to leave the valves open so air can freely enter/exit the engine, which is a much simpler solution than adding a clutch.

The analogy is flawed. The main point is that needing is such an infrequent event for me that relying on Toyota Roadside assistance if it does happen is fine. The type and conditions of driving I do does not have a high probability of tire failure. Furthermore, it's not that I don't have a plan B, it's merely that it is a different plan B. The life insurance analogy is the removal of plan B.

That being said, I realized this spare tire issue is irrelevant upon further examination. As both PHEVs lack a spare tire, it is not an issue that benefits one over the other

 

True its simpler, but if you only use the ICE very infrequently the pumping without oil flowing, plus air flowing through the cylinder is hard on the engine components (and actually releases oil particles into the air, though that is minor). I already get Engine-running for maintenance every 6 weeks that I dont' run the ICE. If they left the ICE connected it would need to be much more often. In a Prius, even the PHV, its not likely the engine will do too long for without a run that provides lubrication.

Also the ICE for the Prius is at the center of the planetary gear, and that would be more complex to clutch in/out. The ICE in the Volt is connected to the generator which is connected to the outside ring gear which is an easier location for the clutching. Also the clutch is part of the switch between series (ICE connectes to generator but neither connected to the planetary) and parallel-series (ice connects to generator connects to ring ring. And it supports generator acting as motor in Ring and none of them connected to plenary. So they get 4 different configuration, to help increase efficiency. So its a clutch vs just free-cycle the ICE.

 

That is an excellent point.

Also, don't forget how remarkably efficient it is to briefly switch to combustion for adding power then quickly going back to pumping air.
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This is incorrect. Prius ICE is connected to the planet carrier. MG1 is connected to the sun.

 

Sorry i was unclear. I did not mean the sun (that would have been easy to say). I ment the ICE is connected to the planet carrier to which everything else connects. In my head i was seeing this drawing

thinking "center" of the planetary gear in the sense that its what is connecting everything. Not "center" as in the sun is at the center. (Physically its not really, see below).

I did not mean difficult because of physical layout, but because of the engineering aspects. Because of the way the Epicyclic gear work, the planet carrier is the element for for applying (prius) (or removing in Volt) maximum torque into (out-of) the system. To clutch that element out is the most difficult positon and would most limit the system in terms of achievable gear ratios, effectively fixing the center of the "lever" I believe this part of the limits of what the Prius PHV can do with the ICE off as it limits how much torque can be provided from MG1 to help MG2 drive the wheels. The same power split that his helping when the ICE is running is limiting when the ICE is off. (Try playing with Toyota Prius - Power Split Device and see what happens when you fix the ice and try to get the ring up to high speed -- you need to overdrive the MG1 at very high RPMs.


Note that physically none of the elements are laid out so any element is really "at the center"

 

I love this discussion and, as has been stated, nice to see we have choices with more coming. I love my 2010 Prius III and thinking about getting a PiP. I'm also intrigued by the Volt.

My daily commute is 20 miles each way but I can't plug in at work, so even with the Volt, I'd burn a little gas on the way home. With the PiP, I'd burn more. Not sure I'd get the full tax credit on the Volt. I read somewhere that you only get the whole $7500 if you owe that much or more. That would make the PiP cheaper.

I have no bias against GM. I owned a '99 Chevy Mailibu for 10 years and it was a very reliable car for the most part. What sold me on the Prius was 1., the roominess (much more than I thought it would be) and 2., the test drive (much better than I thought it would be). 3., the gas mileage is great but wouldn't have sold me without 1 and 2.

I think the potential of plug-in hybrids is great and it gas keeps going up, I think we'll see a lot more interest in them.

The possibility of getting a Volt under MSRP makes it more attractive but I still consider it a first generation product. Even with all the positive comments by Volt owners, I'm inclined to wait a while. I think battery technology will improve. I'd like to see the price come down and the electric range go up. Same with the PiP. We also need more charging stations to come online and quicker charging times.

I think the days of the gas guzzler are over. Of course, there will always be some who will never give them up but the numbers are dwindling. Anyway, it's fun to watch.