Who would buy an AWD Prius?
 

What are the advantages and disadvantages of AWD prius?

Considering the data between HH FWD vs AWD, I guess the only disadvantage is the price premium for the rear elctric motor.

I would buy one in a heartbeat for my wife.

Re: Who would buy an AWD Prius?
 

Wouldn't that decrease FE pretty significantly?

Re: Who would buy an AWD Prius?
 

By common sense alone it means a decrease in fuel efficiency which is demonstrated by all makes and models of cars.

But, to the contrary, Highlander hybrid mileage database revealed that HH AWD is 27 mpg whereas HH FWD is 26 mpg.

Besides, HH AWD is more half second quicker 0-60 mph.

There is only one reason that I can think of. It indicates that 2 traction motors is better than 1 in recapturing energy from regenerative braking.

That is how the toyota hybrid synergy (HSD) primarily excel in city stop and go driving anyway.

One added bonus is the rear traction motor (MG rear) has 50 horses.

Re: Who would buy an AWD Prius?
 

There would be an increase in weight, but overall it's nothing like normal AWD since more electric motor power doesn't equate to less efficiency like adding more gasoline engine power or the extra mechanical losses in an AWD system.

I think they could totally sell an AWD Prius, it would be great for people considering something like a Subaru or even the FEH just to have AWD. It would also definitely make the Prius accelerate faster since most of it's zip comes from the torque of the traction motor, so 2 more tires with a decent traction motor would give it a nice boost.

Re: Who would buy an AWD Prius?
 

Ok, no offence, it's an idea. But in my opinion, it's a waste. Are you going offroading in the Prius since it has such whopping ground clearance? No.
Driving in the snow doesn't justify putting AWD on everything. All you need is a good set of snow tires and some patience. The Prius isn't a high HP car and that works to your advantage which will help you gain traction in bad weather and keep you from driving like a crackhead. Or are you the guy in the SUV that flies past me in a blizzard because he has AWD and then I see 4 miles later turned over in the middle of the highway? As for performance, if that is what you want, then go buy the suby or get a new Si.

Re: Who would buy an AWD Prius?
 

Well, I am not buying a prius for my wife primarily because it is not AWD and the driveway is so steep that there is no way a 2wd can handle it.

A subaru would be fine but I like the HSD technology plus the mileage advantage.

Re: Who would buy an AWD Prius?
 

There are some schools of thought that say that a wheel just rolling along for the ride generates more resistance than a wheel under power -- such that it offsets the transmission losses, etc.

Additionally, spreading the power among four wheels will reduce wheel slippage on dirt and gravel roads, as well as wet roads. Less slippage translates into more forward motion. Add to that the ability to make lighter weight transmission parts as that power is more evenly distributed-- the additional weight of an AWD system would be minimal.

And finally-- sales. People would leap at the chance to get one of those beauties in an AWD model.

My dream car (I swear, I'm not making this up) is a 1997 Toyota Previa with All-Trac. Something about the combination of a supercharger and AWD and the nice space-age looks is compelling. An AWD Prius would quickly replace the Previa as my dream car :) .

Re: Who would buy an AWD Prius?
 

Grew up in PA and seen many 2wd cars make it up some pretty steep driveways. Even my old RWD 86 Monte made it up some steep driveways with studded tires and 200lbs of tar paper in the trunk...lol.

Seriously though, get a GOOD set of snowtires, or studded if you must. if you start slipping you can "walk" it up the hill.

Now coming back down is a different adventure, if sliding is a problem then, even 4wd probably won't help you. 4 wheels slide just as well as 2.

Re: Who would buy an AWD Prius?
 

If they could also increase the ground clearance by a couple of inches, I would buy one THIS MINUTE! This is almost my "dream car". I would pay $30,000 for it.

Re: Who would buy an AWD Prius?
 

:zip:

Re: Who would buy an AWD Prius?
 

And the best part, you can take your AWD Prius on Rally Races! Just kidding.

Re: Who would buy an AWD Prius?
 

Dumb question but why do you assume that an AWD will come with 2 electric motors?

Re: Who would buy an AWD Prius?
 

yeah, prius AWD with a tiny bit more clearance would have us buying two, and my mom buying one too =)

Re: Who would buy an AWD Prius?
 

That's how Toyota made the Highlander 4WD and same with the Lexus RX440h.

Re: Who would buy an AWD Prius?
 

In the GH mileage database, the difference in mileage for the HH between 2WD and 4WD is not significant (even though it is ever so slightly higher for the 4WD). This may be for any of a number of incidental reasons, including locations, driving habits etc... For the FEH however, the difference in the GH database is significant, and the 4WD mileage is less than the 2WD mileage. This supports the contention that 4WD comes with a mileage penalty, which makes sense from an engineering perspective.
with 4WD, you have greater mass to accelerate/decelerate, and you have greater rotating masses as well, which sucks up more gas too (drive shafts and E-motor rotor, minimally). The regenerative braking argument does not convince me unless the changeover from e-brake to mechanical brake comes at a higher decel rate for the dual motor than for the single motor system, but I don't find that likely. Plus, the regen braking only contributes a very small part to the overall efficiency of the HSD, a much more significant part is the operation of the ICE under higher thermodynamic efficiency due to optimal engine loading.
Bottom line I would expect a 4WD Prius to be noticeably less efficient than a 2WD Prius. Personally, I don't see the point and would not be interested, although I could see how folks living in snow and ice territory coudl benefit from 4WD even at a mileage penalty.
:)

Re: Who would buy an AWD Prius?
 

The "penalty" for AWD comes from the mechanical losses and as stated the extra weight. In a AWD Prius, the back wheels would be driven by an extra electric motor (and a second set of batteries) as it is done in the HH and Lexus 400H. This both improves performance and, due to the increased available energy storage, better gas mileage. You shouldn't extrapolate from older designs of AWD in your analysis.

I would applaud a decision from Toyota that produced a AWD Prius as my only hope for an AWD hybrid that isn't a monster (or a Ford) is the promised one from Subaru.

Re: Who would buy an AWD Prius?
 

I would be interested, but for a Prius that's going to go out into the boonies it should also have a decent-sized 12v battery and the ability to jump the HV battery from it (the way you can on the Ford).

Re: Who would buy an AWD Prius?
 

I finally did a little further looking and in my mind, the 4wd Highlander just isn't a real 4wd. At least not to us rednecks...lol. It's definately a city vehicle for your typical suburbanite. Not something I would drive to camp on 10 miles of unpaved road in a foot of snow. It seems that is not what the 4wd system was intended for. The 4wd system on the Highlander is intended more for performance, because those are the only benefits that they highlight on the webpage. So, as for having an awd prius, the benefits would be mostly for performance and not utility. It'll help you in the snow, but only for short periods. So, the question is... what's the point? OHhhh, you have all wheel drive. If the snow's too much for you, stay home and stay out of my way. ;)

Re: Who would buy an AWD Prius?
 

I would buy an AWD Prius (as my second one). The purpose is:

1 - More energy storage for better gas mileage
2 - 4 wheel drive (My current Prius is 2-wheel drive as opposed to my previous Ford Probe which was 1-wheel drive - no traction control) for getting up my steep driveway in bad weather.
3 - Better acceleration (why not?)

As was said here it's not for off road use as the 5-inch ground clearnace is limiting.

ps: Its an interesting engineering project to add a battery, electronics, another computer (with info from the OBD2 CAN bus to know when to add or subtract torque) and two small hub motors to the rear wheels to do this as an aftermarket add-on.

Re: Who would buy an AWD Prius?
 

I would have bought an AWD in a heartbeat when I traded my Outback for the Prius 3 weeks ago! Steep driveway, occasional need to navigate steep grass road by my barn made the Outback and previous Legacy great vehicles - I just wanted better fuel economy. Lot's of rain in the NW and occasional snow, as well as ski trips to the mountains also make an AWD vehicle desirable. Subaru indicated a year ago that it was developing a strong hybrid - I haven't seen anything recently.

Re: Who would buy an AWD Prius?
 

My other car (wife's) is a 97 Outback with 190k miles. I agree they are great cars. I did some searching recently for their hybrid plans. There were two indicators.

1 - They were showing an interesting hybrid at the Tokyo Auto Show this month (a "sport wagon")

2 - Discussion of a hybrid test marketing plan for 07 in Japan.

I'm not certain that my Outback will last long enough for Subaru to get around to selling an AWD Hybrid here.

Re: Who would buy an AWD Prius?
 

Ok.. but those are not cars. They have the room for it. I just think that a AWD system can be made with a single more powerful electric engine. Either that or go to the extreme and make an electric motor per wheeel.

Re: Who would buy an AWD Prius?
 

That's Mitsubishi's Plans for their hybrid.

As for the prius, to each their own. Just personal opinion. For snow, snow tires work on steep driveways, been there done that. Driving through the yard occasionally? The Prius is probably not what you need for that to begin with. It's a great car for it's intended purpose in my opinion. My suggestion, buy a beater....or atv.

Re: Who would buy an AWD Prius?
 

I like the idea. It always seemed to me that a minimal, part time electic drive on the rear wheels would be cheap to do and not decrease the fuel economy much. An occasional burst of 4WD would be useful around here (lots of snow, wind drift, and ice). The amount I might save on snow plowing my driveway could pay for the extra cost. It would take less shoveling to get out of a parking space or my driveway.
I do know about and use FWD with good snow tires on my [non-hybrid] Civic HX. Except for forward traction, the best car for snow I've driven was that Platonic ideal of a winter car, a 1965 Alfa Romeo Giula Sprint, with my '63 Alfa Giulia a close second -- rear wheel drive with studded snow tires in upstate NY. Very well balanced, handled great, even on snow and ice, and stopped well on ice. The three things they weren't good at: starting at -30F (but started reliably at -20F); Italian heater and defroster meant I had to drive with the window open below zero to keep the windshield unfrosted; and it wasn't as good as 4WD at getting forward traction.

--Walter

Re: Who would buy an AWD Prius?
 

i would buy an AWD prius in a heart beat. i have an 06 highlander hybrid and the lease ends next summer. the only reason i plan on buying another highlander is the 4wd (i live in the north country and theres lots of snow in the winter). i would certainly go for an awd prius, or maybe even camry just for the safety of awd. i think it would go over huge.

Re: Who would buy an AWD Prius?
 

RWD, FIRST and FOREMOST...!!!

And even BETTER, what about a Porsche Caymen hybrid...???

Rear engine, RWD and optional R/AWD

With the ICE and primary drive in the rear where it BELONGS, and the hybrid battery in the front to more adequately neutralize the weight bias and provide good traction there for LATERAL, directional, control and stability.

RWD with REAR weight bias would suffice for the majority of us but if there were enough market an electric clutch and driveline to the front wouldn't add that much cost/weight. The electric clutch could be INSTANTLY disengaged when you lift the throttle, even for a slight "coastdown".

Then the engineers wouldn't have to concern themselves overly much about the potential safety hazards of regenerative braking on the FRONT wheels resulting in loss of directional control.

As a driver WHAT would you MOST like to have happen when you hit a patch of black ICE as you enter a curve and the Prius starts "PLOWING", understearing, and you instinctively lift the gas pedal...??

You quite CLEARLY do NOT wish regenerative braking to instantly come on line (IT WILL...!!) in order to QUICKLY recharge an almost "dead" hybrid battery.

But yes, if Toyota has licensed, or cross-licensed, Ford's US patent in this regard, AND the OAT is near the freezing level, the lower level of regenerative braking cognizant with OAT may not be an issue.

But what if the sun is shining brightly and that patch of black ice is simply the residue, shaded by roadside trees, after a sub-freezing night..??

Oh, yes, some of you will quickly move to braking to try to slow the car and thereby help to alleviate the plowing/understearing circumstance and in "this" instance that would most certainly result in QUICK ABS activation. So suddenly, you are now relying PRIMARILY on rear braking to get you out of this mess that FWD got you into to begin with.

But, here again, if Toyota has licensed the Ford patent the instant ABS activates regenerative braking will be disabled, CANCELLED, in order to facilitate ABS being fully functional.

So, how many milliseconds, HEART-STOPPING, HEART IN YOUR THROAT milliseconds, have now elapsed between the time you initially lifted the throttle due to your realization, "seat of the pants"[/B] sensing, of an understearing condition, and your foot (finally) reaches the brake pedal.

Gee, aren't you glad your Prius has ABS and VSC....??

How quickly do you suppose VSC reacts to this plowing incident..??

Does it INSTANTLY disable engine braking AND regenerative braking, ANY level of regenerative braking...?? Does it just as quickly start applying BOTH rear brakes..??

VSC should do all of this even before your "seat of the pants" sensor indicates that "something" is amiss.

But I'd still be much more comfortable with a RWD hybrid equipped with VSC (PSM??).

Re: Who would buy an AWD Prius?
 

wwest, your prayers/lectures have been answered in the form of Lexus GS and LS hybrids. Maybe you can get one (or better yet, both!) and then post everywhere on the internet about the superiority of RWD on slippery surfaces from your own experience.

Re: Who would buy an AWD Prius?
 

Me, in a NY minute provided that was a way to disable the front drive and have a nice solid, stable and SAFE RWD hybrid.

Re: Who would buy an AWD Prius?
 

I believe most of the responses are not directed to the question of "why". The question is not whether AWD is better or worse for mileage. Typically it is, however, that is not the point.

AWD is advantageous in snow/ice. It does not absolve stupidity or recklessness. Regardless, AWD provides more traction than two wheel drive in these conditions. There are those who would NOT buy a Prius unless it had AWD. Obviously this necessity is region/locale centric.

If you think AWD might cost you a mile per gallon... balance that against having to have chains, ending up in a ditch or in a head-on because some one ice plowed your car into oncoming traffic.

JMHO.

Regards

Re: Who would buy an AWD Prius?
 

Re: Who would buy an AWD Prius?
 

Have a look at Toyota's A-BAT concept and their hybrid-X and imagine a crossbreed of the two.

A-BAT is just plain BUTT UGLY but the A-BAT "concept" from the hybrid-X design studio...

And RWD.....PLEASE.