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You guys need to interview Gav. He inspired me and may others to convert our cars to electric.
I always looked forward to his conversion videos.
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The information that we have is that the Cd of the Volt will be between 0.27 and 0.28. The second generation Prius has a Cd of 0.26. So the Prius has a better Cd than the Volt. On the PodCast, it seemed like you said the Volt was better.
The production Volt- probably not, though close. It seems like on one of Lyle's blogs, it was mentioned that the final design would not be locked for a few more weeks, into September. And the look? I liked it- but I agree with Bo- it's what's inside that excites me more than a lonely outer orbit electron! Unfortunately for the outside, Ryan, that shape will constrained by the drag coefficient until high capacity, rapid-charge electrical storage units populate EV's (EESTOR comes to mind!). Once these become a reality, then you will see a sea-change in design since range will no longer be an issue.
And the link to Gav's site is: http://www.kiwiev.com/And the link to Danny's site is: http://www.dannyscontentment.net/
Oh- and just for grins, here is the link to Charlie's (1st post above) own ongoing EV project- makes me proud of my fellow Texans;-) http://mcrickman.com
I noticed that in a couple of shows you seem to indicate that a serial hybrid system is preferable to a parallel hybrid system, and have also said the parallel system requires the use of the ICE more than a serial system. I don't think this is true.
For example, the design of the parallel system in the Prius allows:
1) the car to be propelled using just electricity at any speed
2) the car to be propelled using just the ICE (i.e. not the battery) at any speed, and to do so efficiently
3) the ICE to be used to just charge the battery and provide no propulsion
4) any combination (%) of battery and ICE for propulsion at any speed
I think the confusion comes in when thinking about how the Prius actually uses its parallel system in the current car. Since in the current Prius all energy ultimately comes from the use of gas in the ICE, the software optimizes the use of gas rather than trying to maximize the use of electric only mode. But even the current Prius can and does run in electric only mode up to 63 MPH given conditions that make that the most efficient use of gas. The current Prius does, however, spin the ICE whenever the speed is above 41 MPH. (Spinning the ICE does NOT mean that it is using gas though since it can spin it via the electric motors.) It does this to keep the RPM of one of the motors (MG1) below 6500 RPM. (It seems that MG1 was originally rated at 6500 RPM, but is now rumored to be rated at 10000 RPM.) Anyway, all of this is just software controlled, and in a plug-in hybrid, the use of the ICE would be very different since the energy is no longer just coming from gas. In fact, the prototype plug-in Prius being demoed by Toyota appears to just have different software, not hardware, as far as the drive train (excluding the extra battery). As for the hardware, a simple change of either the max RPM of MG1 and/or the gear ratio would allow electric only operation with the ICE at 0 RPM up to the maximum vehicle speed which would allow more efficient battery only operation at the higher speeds.
Another confusion point may be that Toyota is only claiming a short battery only range ( < 13 miles?) for the plug-in Prius. This is really just a trade off of cost + weight versus range though.
A serial hybrid design will be less efficient than the parallel hybrid design (as in the Prius) whenever the car is using the ICE. This is because of the efficiency losses when going from gas to electricity then to motion in the serial hybrid versus just going from gas to motion in the parallel hybrid. So I think a Prius like design will be more efficient than a Volt like design when operating in "range extended" mode after the battery is depleted.
The serial hybrid design is probably cheaper though, and is certainly more flexible with regard to power source (ICE vs Hydrogen fuel cell, etc.). And it is certainly much closer to the design of a pure BEV.
In summary, I think both serial and parallel hybrids have their place, and the best choice depends upon the total requirements including expected normal range, cost, weight, etc.
Fiill up your gas tanks this weekend guys! Hurricane Gustav ballooned to a Category 3 Huricane yesterday, and may get larger as it sucks up enery from the warm gulf waters. From the AP on Hurricane Gustav:
"As much as 80 percent of the Gulf of Mexico's oil and gas production could be shut down as a precaution if Gustav enters as a major storm, weather research firm Planalytics predicted. Oil companies have already evacuated hundreds of workers from offshore platforms.
Retail gas prices rose Friday for the first time in 43 days as analysts warned that a direct hit on Gulf energy infrastructure could send pump prices hurtling toward $5 a gallon." (Emphasis added;-)
(And, though I emphasize its impact on Gas due to the nature of this web site, let's not forget the other dangerous aspects of this Hurricane- 80+ people have already died from this storm, and projections give it a fair chance to head to New Orleans)
I would be very interested to see where you got that info about the prius. All info we have found on current plug in Priuses and future (including statements from Bob Lutz as early as yesterday), the plug-in prius requires gas and the use of the ICE -- all electric mode is only a) below a certain speed b) when hard acceleration is not needed c) when battery temps are not too hot.... etc. We have seen this in the plug in Prius we drove (Spirit of DC), as well as testimonies from other drivers.
If this info is incorrect and the Prius will be able to operate as a full electric vehicle, please point me to some on that. I will do some more investigation and get the correct info out to our listeners.
Steve, I think you have a good explanation of the serial versus parallel hybrids. I too believe they both have their place and could both potential have a significant electric only range.
However, my understanding of the Prius is that the electric motor does not have sufficient torque to provide the desired acceleration. For that reason, under hard acceleration, both the electric and ICE motors are used. So I think Toyota would need a bigger electric motor if they we going to force the ICE engine to be off for 13 miles.
I think the point that Bo is making is that it is nice to a have a vehicle that has a signficant electric only mode and use zero gasoline. I don't think Toyota is heading in that direction. The plug-in Prius will make good use of the electric energy, but will always use gasoline to suppliment.
John C. Briggs
The electric motor(s) in the current 2008 Prius is rated at 67 hp and 295 ft-lbs of torque. While not in the same class as a Tesla Roadster, that is plenty for all electric operation of the Prius at any reasonable speed. However, the current Prius does use the ICE for hard (or even reasonable) acceleration, and when above certain speeds because that is the most efficient use of gasoline. But that is not because it is a parallel hybrid. It is because all power (even for the batteries) ultimately comes from the ICE / gasoline. With a software only change and more battery capacity, it could run all electric at any speed. (But high speed operation with the current gearing would not be as efficient as it could be.)
The current add-on conversion kits are all still restricted to using the current software. Even so, they are able to achieve all electric operation for quite a wide range of speeds and for a range of >22 miles. (See the following link for an example.) (Here is a quote to whet your interest: "For an example during highway driving you can draw about 40-50 amps at 55mph in warp stealth and you can hold 55mph and even accelerate using no gas. You can do this or let the engine run and get 150+MPG and the battery will last longer. It really all depends on how far you have to travel on the highway and how much you want to use the battery. Do you want to use it all up on the highway or do you want to EV around the city? Or do you want to do a little of both? ".)
With different software, such a plug-in addition could do even better.
As for where I got my information, it is both from being the owner and driver of a Prius (while waiting for an affordable EV), and from the wealth of information at http://priuschat.com. Since there are some significant hills in upstate NY, I regularly see electric only mode even at highway speeds (65 MPH). (This happens when the battery is highly charged following down hill sections, and when the load is light enough that this represents the most efficient operation for the vehicle as determined by the software.)
It is probably true that the Prius would not use the batteries if they are too hot, but I have never seen or heard of that happening. The batteries are cooled by passenger compartment air via a fan if needed. It is likely that the passengers would be quite hot as well if the batteries were too hot!
As for the future Toyota plug-in Prius, all we really know is that Toyota is planning on a fairly short all EV range (<13 miles?) (again a cost-weight vs range trade off), that it will have an even larger electric motor(s), and that it will be able to normally run in all electric mode up to at least 62 MPH. (Isn't that the same as the Vectrix?) But there really is nothing fundamental that prevents running in all electric mode up to the vehicle top speed given either a higher RPM rating on MG1 or different gearing. Will the Toyota plug-in Prius use the ICE more than a GM Volt, even in the first 13 miles? We don't really know, but it would not surprise me. But again, this is not due to a parallel hybid drive train requirement.
But enough on the Prius. The real point I am trying to get across is that a parallel hybid drive train does not by itself make a car less capable of all EV mode operation, and will tend to be more efficient when and if the car uses the ICE. Whether or not Toyota releases a plug-in Prius which minimizes the use of the ICE remains to be seen. (I tend to doubt it because, if nothing else, all heat for the passengers comes from the ICE right now, and this means ICE operation in the winter for the northeast.)
As Bo recently pointed out, GM is planning to only run the ICE enough on the Volt to keep the battery at a 30% or so charge. They could have chosen to run the ICE to fully charge the battery once it was depleted to 30%. Or, as an absurd case, they could have chosen to run the ICE to fully charge the battery whenever it dropped below 90%. In all cases, the system would still be a serial hybrid design, but some uses would run the ICE more often than the others.
(Another good reference site on the technical aspects of the current Prius drive train is:
when looking at the simulation, just remember that the ICE can be spun via the electric motors without using any gasoline.)
Steve, Thank you for the clear explanation.John C. Briggs
So basically what I would like to know is it possible to remove the engine in a Prius and run the car on all electric mode? 2008? 2010?
"BillB So basically what I would like to know is it possible to remove the engine in a Prius and run the car on all electric mode? 2008? 2010?"
You could remove the ICE from a Prius (any year) and the physical hardware would be there to run as a pure electric vehicle, but to be practical, you would need to:
I noticed another interesting quote from Bob Lutz as reported on the GM-Volt website:
'He noted that one of the major challenges in the vehicle is to write computer code for the “zillions” of possible interactions between the driver, electric drive, battery, and regeneration and when the combustion engine should come on.
With respect to that, he describes an interesting scenario where its 40 below in North Dakota and the battery needs to be warmed in order to function properly. He notes this would be a big challenge for a pure EV, but in the Volt the car would start out with the combustion engine on and “run for a few minutes to warm up the battery so that the battery can take over.”'
I think that makes perfect sense. But it does seem to indicate that the Volt may not always operate like a pure BEV in the first 40 miles.
p.s. Based on what we think we know about the Volt, I would much rather have the Volt than my current (non-plug-in) Prius even though I really like my Prius for what it is! I really, really hope the Volt is successful!
Amen to that Steve! A successful Volt will have an impact on several fronts. It will buoy GM, perhaps back into profitablity more quickly, it will shift the lead in EV technology, including batteries (assuming A123 is chosen) back to the US, and it will push ALL other automakers to respond with larger EV production runs of their own. Conversely, an unsuccessful Volt may be the death knell of GM (or at least make it much harder for them to return to the pedestal of World's Number One Automaker any time soon, if ever), will put the lead of EV development and advancement back to an overseas company, and will probably slow down the adoption of EV's as a whole- which has its own set of dire consequences;-)
Steve, thanks for your explaination of the parallel hybrid operation. That is how I understand it also (I am a Prius owner also). I also have witnessed all electric operation at higher speeds. I would also point people to the plug-in conversion http://www.pluginsupply.com/ which also talks about all electric operation up to 52 mph with the current prius (and a software "patch").
Bo, if the parallel hybrid works as we believe that it does, the general public will not care or even know the differences between serial versus parallel as long as it gives them the all electric operation (even at high speeds) and then reverts back to gasoline whenever the battery pack is depleted. As I see it, a plug-in Prius could be an equal competitor to the chevy volt, only available sooner, probably cheaper, and with more years of reliabilty behind it.
Love the show and would like you to interview someone involved in the plug-in conversion arena to clarify these points.
it gives them the all electric operation (even at high speeds) and then reverts back to gasoline whenever the battery pack is depleted. As I see it, a plug-in Prius could be an equal competitor to the chevy volt, only available sooner, probably cheaper, and with more years of reliabilty behind it.