How will the Chevrolet Volt be better than a Toyota Prius plug-in hybrid?

Every plug in that I am aware of functions exactly the way you describe once the grid charge is depleted (except for pure BEVs of course).

I don't find plugging in to be inconvenient at all, about 10 seconds to take the plug off the wall mount and stick it in the car; much more convenient than driving to a business to stand in the cold and pump gas for 3 minutes.

 

Have to agree with gwmort on this one.
Plugging in at home is so much more convenient for me. No need to add 5-10 minutes on my trips when low on fuel. No need to pump gas into my car in blizzards

Now, this isn't true for everyone. I am sure people that don't have an outlet in their garage, or don't have a garage may find it less convenient.
I for one do not miss my stops at gas/"convenience" stores.

 

In in SE PA, electricity for a PHEV is much cheaper per mile than Gas. to be comparable one needs a kw to be about 9% of a gallon of gas, so if your gas is 3.50 your electricity would need to be about 31 cents oer kwr to be comparable.

I'm with gmort.. at least if you own a home with a garage, plugging in is way BETTER than getting gas. Takes me maybe 4 seconds (my plug is hanging above the car, just unhook and plug in, flip switch on the way in). Gassing up was such a hassel in the cold-winter winds often needing it when I was dressed for a meeting or running late. I last filled up in October.. I much prefer running on the wind and skip the windy cold winter fill-ups

 

Yeah, it sure is a bummer having to spend all of fifteen seconds plugging in my car every single day, and then having to unplug it in the morning. (I must be older and slower than gwmort, since it takes me about five seconds longer.)

Seriously, though, it's a lot more of a hassle stoping at a gas station and pumping gas. You still need to pump gas with a PHV or REEV, but not as often as with a gas car.

It actually takes me longer getting the groceries out of the trunk, and closing the trunk, than it takes to plug in the car.

For me though, it's not about the convenience or the cost. It's about the serious consequences of burning petroleum: Pollution, global climate change, balance of trade, the "terrorism tax," the depletion of a resource that has other critical uses, etc.

 

There is an underlying assumption here that the two cars will have similar reliability and repair costs.

HAH!

 

Volt take 2-3 seconds when shifting a gear, even in EV mode (maybe faster). Prius PHV never need to shift from 0-112 mph.

 

Not quite true . The Volt in EV mode does not need to shift in going from 0-101 (its limit). And is faster in acceleration than the PHV in 0-X as well. In CS mode in 0-101 it will not shift either.



The only way to get it to shift is to be going at a steady state and allow it to switch modes (two-motor EV or to serial in CS mode). It reconfigures the planetary gearing from the more efficient mode to "power mode" when one asks for significant acceleration, just as the Prius may engage its ICE when asked for significant acceleration.
But the "gearing change" is not what I would call a shift - shifting there discrete changing in the gear ratios and a point when there is no direct power to the wheels. During all changes the volt/PHV are continuously varying the rations and are always providing power to the wheels. They are just changing some internal mechanisms.


If you consider changing internal setups "shifting" then
the Prius PHV however MUST vary its gearing (i.e. shift) as the ICE comes on. But both cars do internal reconfiguration without removing power from the wheels, so in my view neither car "shifts", just electronic changing its effective gearing and power source while continuously providing drive power.

 

How do you explain the gear shifting from changing the "throttle" from 29% to 32%?

In 3 seconds at 32% "throttle", Volt gained 1 mph in acceleration. That's a pretty good gear shift lag.

 

I've never experienced this shifting you speak of in my Volt.

Closest thing I would describe to a shifting sensation is if I am in CS and try to accelerate quickly, there is a lag between when the power begins to be consumed (instantly) and the ICE realizes it needs to run harder to keep up with the electrical draw, so sometimes you'll feel the ICE kick on or get louder a few seconds after depressing the accelerator, but the acceleration itself was already underway.

Its actually quite novel because instead of the pause, audible cue, then g forces of acceleration from a shift you experience the g-forces first, then after a brief pause the audible cue.

 

I have no idea to what source of data you are referring so I cannot possibly explain what it the cause. Can you provide an reference?
What was measuring 29% throttle? 32% throttle?


Since the Volt does 0-60 in 8.3 seconds (Motortred got 9) hard to imagine where you would find 2-3 seconds of lag.

Stating 29% acceleration positon presumes some OBD2-tool monitoring it. I do Troque monitoring of my Volt and the mapping from pedal to requested throttle to actual acceleration is quite non-linear as are many of the data items in the car's OBD2-> performance Also remember there is truncation as its working in fixed point math.

My best guess for what it seems you are describing might be that the 29%-32% pedal position was that the mapping of petal to requested throttle/acceleration is so dense that those measurements are almost the same and the speed differences are nearly unmeasurable given other random variations.

 

Check this out. I was looking at the schematics.

MDI screenshot shows it went from 55% calculated throttle to 32% but they are 8 seconds apart.

BTW, they are calling it power split mode when the gas engine clutches to the wheels. We know Volt doesn't have the power split setup.

 

Didn't read through it all, but looked at the pretty pictures. One problem with hybrids is mapping and sounds, and it may be best to get better mappings and just quiet the sounds.

The volt seems to be doing a dance to engage clutches to move to different modes. At low enough pedal levels, precise power could reflect pedal position, while the noises coming from the ice would not reflect at all what is going on. Since the battery is supplying energy to the traction motor, it is up to the mapping to figure out what is going on. I leave it to volt drivers to say if they like the mappings or not. I get a similar mush on my prius sometimes where there is a time delay between requested power and power going to the wheels. I assume this is more efficient, but it may just be bad mapping.

 

We is wrong. The term "power split" as used in engineering is perfectly valid for both input split (Prius) and output split (Volt) planetary gear hybrid transmissions.

 

I'm under the impression there are clutches in the Volt, which alter that way stuff is connected to other stuff. For example, the ICE can be connected directly to the wheels, or disconnected from them, via a clutch.

In the Prius, there is no clutch. The way all the stuff is connected to the other stuff never changes. What changes is the flow of electrical current among the battery and the two motors, and whether or not the ICE is running and at what RPM and how much gas. When the ICE is running, 60% of its torque ALWAYS goes directly to the wheels, and 40% ALWAYS goes to MG1. But because work is force (or torque) times distance, the proportion of power flowing the two routes is always changing. But the physical connections never change. No clutch.

I personally consider this (Toyota's system) to be mechanically more reliable than the Volt's system.

Of course, pure EV is more reliable yet. And if we're talking about smooth power from zero to max, Tesla's light-years ahead of both Prius and Volt. (I never got to drive the Leaf on the freeway, so I don't know how it behaves at the upper end, but I'd bet on my Tesla against the Leaf also. )

 

Those are not from an meaningful acceleration profile. WOT went from 0 to 60 in about 38 seconds (i.e. very slow). He was trying to go slow enough to allow his software/screen capture images of the transitions. He was not trying to see what lags occur. The 55% throttle down to 32% show you that he reduce the throttle (i.e backed off on acceleration) trying to slow down. That much back off could even have produced regen.. You can draw no conclusions about gear switching speeds from that data.

 

At 50% coal fired power (national average)-
...3674 kWhr is approx. = 50%x3674 = 1837 lbs coal = 295 gals gaso

If the % coal is higher, then adjust accordingly. My way of thinking is Volt gets about 35 MPG fossil fuel equivalents, assuming 50% coal in the mix.

So Volt gives you a nifty choice, you can get 35 MPG on gaso, or 35 MPG on coal. Take your pick! ...and that's a rhetorical question, as many here have already indicated their preference.

 

But with the volt you get a choice of how to power it. You can choose to go way greener.. pay for solar or Wind to drive the EV part, and use gas only when you really need it.

Even if they don't pay extra for green energy, national averages don't really apply. People live in one area and the areas that tend to buy HV/EVs (and volts) tend to be way greener than the average grid.

Check out this post (from another PC thread) where there are maps of where a EV (roadester) is greener than a Prius, as well as a map of EV sales locations
http://priuschat.com/forums/chevrol...nsider-chevy-volt-instead-20.html#post1472546

Clean energy and HV/EV sales are very strong correlated.

Also consider this post
http://priuschat.com/forums/chevrol...nsider-chevy-volt-instead-19.html#post1472345

Which is different data.. same conclusion. And usbseawolf2000 has a whole thread about a a zipcode-based calculator
http://priuschat.com/forums/toyota-prius-plug-in/103819-beyond-tailpipe-emission-calculator.html
And there are plenty of other posts about that calculator too.
So people can check their domain

 

295 gallons equivalent + 52.5 gallons = 347.5 gallons consumed.

50 MPG Prius would consume 243 gallons over the same 12,152 miles.

 

The choice is good but at lower total efficiency for a compact car. Prius PHV would maintain 50 MPG on gas and higher efficiency on electricity (than Volt) plus the mid size interior that retails lower.

 

Its not just the choice of power source, its also overall efficiency.

95MPGe vs 94MPGe.. is not much more efficient and that is only for 11 miles for Prius PHV vs 35 for the Volt. For many drivers the Volt is way more efficient overall because they can get a larger amount of their total driving at the 94mpge.