Toyota Prius

ateixeira · January 2004

105? :oO

Take it easy, you have to have the car in control to be able to avoid obstacles. Like fallen pom-poms.

-juice

mswbest · January 2004

If any one cares I bought my 04 prius In October with package 9. The color is the green-silver one(It is my favorite color for the 04 prius aside from black).And for your information tehy called me on the 16 said that "he has one coming do i want it?" w/o deposit. No one else went to TOYOTA OF ORANGE everyone else is on a huge waiting list for the LA dealers. NO list at my dealer.
Anyways We went in friday night and we paid cash and drove it home 1 1/2 hours later.I wrote the check for $28,500. There was no over-list price. Just the amount on the sticker and taxes. I love my car. AND my dad is getting the toureg this weekend you could check my post there too.
Oh and all my friends refer to my car as "Hybrid"
Ex. "Let's take hybrid out to lunch today"
Good-Times

backy · January 2004

So you wrote the check for $28,500? And you're 16. Can I have a loan?? ;-)

My 15-year-old son thinks the Prius is pretty cool also. He gave it a thumbs-up when we went for the family test drive, before I ordered it. That may be partially because the alternative to the Prius is a mini-van or a mid-sized station wagon. But I think he likes the techie flavor of it (he's something of a computer geek) and the swoopy styling. Our first color choice is the Tideland Pearl (that's the color of yours, right?). I haven't seen any of those on the road--does it really look green? In pictures it looks more grey.

mswbest · January 2004

Yes, it wasn't my signiture it was my fathers. My prius is the Tideland pearl and it is silver-green in the sun and silver-gray at night. It is a GREAT color. And if i were your sun i would go with the prius too.
I dont know how much you are willing to spend and how short of a leash you will keep your son on but I have used the Navagation system more than 50 times and i would have been lost 10 of those times without it. I really recommend it, all of our cars now have it. I just need it because Idrive alot and LA is just so big and i have alot of friends that live in different places. It is so much easier to reach them with the Nav system, it has saved meover and over. You will love the car backy with or without the nav.(but get it you wont regret it)

backy · January 2004

Just package 3--side bags/curtains and rear wiper. But at least my son has a cell phone, in case he gets lost when he's turned 16 and is out driving on his own. We also have the trusty Hudson's Street Atlas--worked pretty well for me for 30 years, and it costs a mite less than the nav system.

Glad to hear the details on what Tideland Green looks like--I think I'll like it.

cat42 · January 2004

I'm on the verge of a decision between the purchase of a 2004 Prius or 2004 Forester XS and could use perspectives from others. I'm struggling with the tradeoffs: (1) The incredibly well-engineered, efficient Prius appeals (big time) to my environmental conscience, and my desire to "put my money where my mouth is." However, (2)The Forester would do a fine (better?) job carrying a sea kayak (16 ft) with gear (paddles, dry suit, etc) and/or a bicycle, and with the greater clearance, would handle gravel roads better overall (not speaking of majorly rutted, "off roading"...just standard gravel roads, logging roads in the Northwest, etc.)

Neither Yakima or Thule make a kayak rack for the 2004 Prius, although Yakima says they may in the future if there is enough demand. Looking at the profile of the Prius, I wonder if it will even be possible.

If Yakima or Thule discover that a kayak rack is possible to design for the Prius, I realize that carrying a kayak will significantly reduce fuel efficiency, and that's okay...95%+ of my driving will not involve a boat or bike, so on the occasions that it does, I'll tolerate reduced efficiency (as long as the car tolerates it).

John1701a, your website shows your bicycle rack on the classic Prius; have you tried it yet on the 2004 Prius? And by the way, thank you for your website -- it's really helpful.

I would welcome thoughts from anyone regarding the possibility of occasional transport of bike or boat on the 2004 Prius. Thank you!

m4eth · January 2004

I too am deciding between the Forester and the Prius...two different animals...one built for strapping bikes and boats and the other HIGH TECH GREEEN for sipping fuel...but I live in a region where my primarily concern is icy roads in winter but main driving habit will be IN CITY driving so MPG is the major concern.

I'm divided between the Forester with a proven ALL CONDITION SAFE operation record (excellant crash ratings) and the Prius a FAIR WEATHER machine (built for the road)with unknowns because it's so new.

Would like to know what folks are getting on their new 04's for mainly IN CITY driving??? Prius specs state 60 city so I assume in northern climates that would be reduced somewhat because of temperature.

Thanks, for any input you can provide.

Mike

john1701a · January 2004

> John1701a, your website shows your bicycle rack on the
> classic Prius; have you tried it yet on the 2004 Prius?

Sorry, Minnesota Winter has delayed my bicycle rack research. Test fitting one on a car covered with road-salt & sand in temperatures well below freezing is just plain out of the question.

Instead, I'll be waiting until March and taking advantage of the usual start-of-the-warm-season sale prices to get a rack that fits on back.

Realistically, I don't plan on using the rack a whole lot, since 2 bikes will fit inside fairly easy if you unclip the front tire off.

JOHN

john1701a · January 2004

> the Prius a FAIR WEATHER machine (built for the road)
> with unknowns because it's so new.

Huh?

This is WINTER #4 for me. My classic was exposed to -13^F driving and my 2004 exposed to -2^F last week and will again next week. And two summers ago, I did some driving in temperatures just above 100^F.

"FAIR WEATHER" is clearly not accurate.

> Would like to know what folks are getting on their new
> 04's for mainly IN CITY driving???

What does "IN CITY" mean?

If that means, no faster than 30 MPH with very frequent stops and trips no longer than 15 minutes, then the question is warrants a basis of comparison. Traditional vehicle performance under those conditions totally sucks, they get significantly below the EPA estimates. So I myself would like to know what they actually get (vague data hints at below 20 MPG). A 2004 Prius will typically deliver around low 30's in those extremes.

If your "IN CITY" definition is suburb driving (the 35 to 50 MPH range) with occasional stops and trips longer than 15+ minutes, you're MPG will be pretty sweet... mid to upper 40's in the winter and upper 50's in the summer.

JOHN

djasonw · January 2004

I left the house at 6:45 this morning, OAT was 2 F. and booted up the Prius. Amazing how you don't even hear the typical crank of a starter. I took off nice and slowly and headed to the highway and cruised at 70-75. Battery meter NEVER appeared different than if it were 50 or 60 degrees. I think the Prius handles the cold BETTER than a conventional car! Heck... I had heat cranking in 7 minutes or so!! When I got off the highway (17 miles) I was at a light with engine off (as usual) and 9/10 green. Simply AMAZING!!

m4eth · January 2004

Do you garage your Prius??...or has anyone left the car outdoors??...for example leaving the car at the airport for an extended time during travels when temperatures are very cold...the heated thermos only lasts for 3 days so I wonder if you have extended travel over three days and the car is outside exposed to freezing weather...what happens to the car???...

Fair Weather can also mean you drive from garage back to garage....temperatures then when parked for extended periods are still above freezing...thus FAIR Weather.

Mike

gscheil1 · January 2004

John - Somewhere I saw how to change the unlocking so all doors unlock but now I can't find it. Can you re-post it?

priuspete · January 2004

All:

I drove the prius this morning and the temperature was -23 degrees C . I drove it slowly as I do most cars when they are cold but the wierd thing was how the engine revved really high even though I was at a low speed ( 35 km/h). It felt like the gears were slipping. As the car warmed up (10 minutes) the "high-revvingness & slippage" went away.

Anyone experienced this?

wwest · January 2004

at those temperatures the CVT fluid has frozen and the CVT couldn't "shift" out of low range. Years ago in Alaska even the power steering fluid froze.

gscheil1 · January 2004

I found it-
Simultaneously push and hold the top button nd the panic button for 5 or 15 seconds or somewhere in between and it will start cycling through 3 options. Just play with it for a while and you'll figure it out.

texassalsa04 · January 2004

I have also noticed the high reving ICE when the car is cold when driving out of my garage and onto the street. I have also noticed that first thing in the morning when the car is stopped at the first stop light on my way to work, I feel it lurching (or shuddering) while I have my foot on the brake. I wonder what these "symptoms" really mean. I figure they are just charactersitics of the Prius and I am not going to worry about it. John? any thoughts on these incidents? You must have felt these "symptoms" on your Prius have you not?

john1701a · January 2004

The high revs is because you are braking harder than normal in the cold. In the previous design, that set you up for a potential automated stall/restart sequence. In the 2004, it is simply avoided by revving the engine. It's just way the Planetary-CVT is setup.

You'll also discover higher RPM sometimes when driving cruising along in the cold. Since the system has to generate heat anyway, it takes advantage of that and recharges the battery-pack more than normal. Measurements have shown that greater amperage is allowed to flow through in the winter than in the summer, allowing you to take greater advantage of the electric motor. The thought is, because it's cold there is no worry about keeping the battery-pack cool.

That lurching while stopped at a intersection during warmup is a bit odd. I've felt it too, and it wasn't there with my classic. The system is apparently doing more than simply moving pistons. It might have something to do with the secondary coolant circulation. After the head of the engine is warmed (using the coolant stored in the thermos), the remaining hot stuff if flushed to the lower part.

JOHN

little_pogi · January 2004

This is a simple question to answer. Those who like to load up their car with outdoor stuff, the Forester is a hands down winner. Loading bikes, kayaks, snowboard on the Prius via external racks defeats the aerodynamics of the car. Yes your can find some ways to load up the Prius from the outside but I think Japanese engineers designed the Prius to be more of a people transport car. It would be interesting though to see a Prius zooming by with a Kayak attached at the top of the roof.

john1701a · January 2004

> I think Japanese engineers designed the Prius to be more
> of a people transport car

The fact that it's a hatchback clearly indicates otherwise. Just drive with the back seats down for awhile. You'll discover just how much cargo you can get back there, without having to compromise aerodynamics. Tossing a bike back there is effortless (two takes some wiggling, but is realistic).

The attempt to cross-class compare Prius to another vehicle has never worked. People have been attempting to for many, many years though.

Prius offers far more utility abilities than a sedan, but it is clealy not built for typical towing or typical roof-top cargo carrying. It can, but in general that's not what it was designed for.

> It would be interesting though to see a Prius zooming by
> with a Kayak attached at the top of the roof.

Not really. I used to carry an aluminum canoe on my Omni. That was larger cargo on a smaller vehicle. It worked fine. No big deal.

JOHN

revnkevin · January 2004

On Friday, I went from Fresno to Orange County, in Cailf. I set the cruise @ 65,and it was 70 degrees outside and I had about 1 hour of stop and go traffic in down town LA. I went 290 miles. It took just 5.54 gals. That's 52.3 MPG.The 04 Prius got the best MPG in stop and go traffic. I went over 30 min and got 100 MPG for that whole time. Today when I left it was 70 outside,and I was getting in the low 50's, for Mpg, but it got cold and foggy,my Mpg went to45MPG,Yes from 70 to 45 and foggy will make your MPG go down! I saw it happen in 10 min!

priuspete · January 2004

John:

Are those real concrete facts or are you rationalizing(guessing) the actions of the prius on cold starts?

Why would a prius use the brakes harder in cold weather? I was driving on cleared roads. Did not have to apply any more pressure than necessary.

The car would acutally know to rev higher in colder temperatures? Could it be that the is reving higher to heat the engine faster?

I'm suprised texassalas's prius is high reving. Aren't you in Texas where it is quite mild?

john1701a · January 2004

> Are those real concrete facts

I used the word "apparently" for a reason. (That means very likely based on design, but we can't find proof for that exact condition.)

> Why would a prius use the brakes harder in cold weather?

Ice, Snow, another vehicle...

> The car would acutally know to rev higher in colder
> temperatures? Could it be that the is reving higher
> to heat the engine faster?

This is an increase in addition to the higher RPM attributed to normal cold weather warmup. It's pretty obvious, since it occurs the exact moment you exceed standard braking pressure. Nothing surprising, since the operation of the vehicle doesn't change.

JOHN

talleyid · January 2004

Actually my wife and I have both of these vehicles now. We are a die-hard Subaru family and she has the 2004 Forester XS. I replaced my Mazda B2300 Pickup with the 2004 Prius. We've always had at least one Subaru because of their reliability and now the all-wheel drive for our current occasional winter conditions. Honestly though we've only had a couple of occasions per winter that the Transportation Department couldn't get the Interstates cleared well enough for any reasonably cautious driver in nearly any vehicle.

I think you're going to need to decide what you need your vehicle to do and then make your decision based on that. In my opinion the most significant factor is the actual road conditions you'll be encountering. Obviously the Forester has higher clearance (7 - 8 inches I believe) and is more suitable for "off road" conditions. If the roads you're using are reasonably well maintained and level the gravel surface shouldn't be an issue for a Prius.

Some questions I'd be asking myself. How often will I be "off road"? What are the worst case conditions I intend to encounter? Will I require all-wheel drive, etc.?

While the Prius is as versatile as any sedan in my opinion, it is not an SUV or off-road vehicle. It's primarily a commuter vehicle like any other mid-size sedan.

If I can provide any specifics on either vehicle please let me know and good luck in your decision.

texassalsa04 · January 2004

Yes, here in the Dallas area, we have had some very temperate winter temperatures. Highs in the low to mid 60s and lows in the 40s...we have had a couple of cold snaps in the 20s and 30s but it just has not gotten that cold yet. My Prius is garaged and in the morning it gets warmed up pretty fast. Yes, I do get high revs and lurches even in this temperate climate...

ateixeira · January 2004

I will start by saying I test drove and thoroughly enjoyed the Prius, and think a hybrid SUV or minivan just might be in my future, I was that impressed.

However, I always say "The Right Tool for the Job", and let's face it, the one to carry bikes and kayaks on gravel roads in winter weather is the Subaru, hands down, no comparison.

Look at the all weather/terrain features of the XS model that are relevant to this shopper:

* AWD
* rear limited-slip differential
* heated seats
* heated side mirrors
* front windshield wiper de-icer
* rear windshield wiper de-icer
* 7.5" ground clearance
* long travel suspension
* 150 lbs roof rack capacity
* full size spare tire

Get the Prius for efficient commuting, the Forester for the outdoor stuff you say you'll be doing.

Want a compromise?

Check out the PZEV Subaru Outback in California. You give up a tiny bit of HP (163hp overall) to get PZEV emissions. So an Outback with the AWP would be a good compromise between the two, and you can buy one for under $20 grand.

Until the Hybrid Highlander arrives, that's about it.

-juice

arachne · January 2004

Yes - you read that correctly. We're thinking of purchasing a used 2004 Prius, but have some tax questions. My understanding is that the $2,000 is a deduction, so the current owner gets to deduct $2,000 from their income, thereby receiving a tax break of approximately 30% on that $2,000 (assuming they're in the 30% tax bracket - about $600). But what about state taxes? If the state income tax is approximately 5%, and they use the federal adjusted gross income on the state form, then they essentially get an *additional* tax break of approximately 5% on the $2,000 ($100)? So the total financial benefit would be $700. Have I calculated that correctly?

And can anyone think of any financial reason why I shouldn't do this if we pay what she paid for it originally (minus the tax break, that is)?

Thanks.

john1701a · January 2004

> Looking forward to more Owners information and experiences

There were a few in "Parade", that color magazine included in Sunday newspapers throughout the country. On page 12 of the January 11, 2004 edition is a bunch of hybrid related stuff. On page 13 are comments from me. Check it out!

JOHN

Sylvia · January 2004

FYI - a number of posts were removed as they were:

-detracting from the conversation and off-topic
-personal attacks that were uncivil

Come on folks, agree to disagree and move on. The Prius is a fantastic car with interesting and innovative technology. Prospective buyers are here looking for information, let's put our personal best foot forward and help them out by staying on topic.

wlblackwellpe · January 2004

From the 2004 Prius Owner's Manual.
Page 114- The gauge indicates the approximate quantity of fuel remaining in the tank when the IG-ON mode is enabled. Depending on the ambient temperature, the fuel quantity is less than 45 L (11.9 gal.) even at "F". However this does not effect the fuel consumption and the remaining fuel ratio indicated on the gauge.
Page 204- The fuel tank capacity is decreased at low ambient temperature. (decrease by about 5 L (1.3 gal) at 14F.

geogirl · January 2004

Arachne,
It is my understanding that the vehicle must be new to get the tax deduction i.e., only the first owner gets the tax deduction.

http://www.fueleconomy.gov/feg/tax_hybrid.shtml

Also if the vehicle is purchased this year, the fed. tax deduction has decreased to $1500, but I agree with your assessment of decreased taxes on the state level because of the federal tax deduction. It actually might even be more if your state offers any tax incentives. For example, Colorado is giving a tax credit of $2678.
http://www.revenue.state.co.us/fyi/pdf/income09.
pdf

talleyid · January 2004

Thanks for that info. I haven't read the entire manual yet and didn't even check into that portion before complaining to Toyota. I'm still going to question them regarding their response that "3-4 gallons of diminished capacity has been reported and not considered a defect."

They replied that they would be looking into the matter and would communicate further information to the dealerships.

hans000 · January 2004

I am convinced the "lurching" (or shrudder) while stopped is caused by AC compressor. When I adjusted the temperature down to the point the blower slows, the shrudder was gone.

Looks like the AC runs for both warm and cool.

===============
jone1701a wote:
That lurching while stopped at a intersection during warmup is a bit odd. I've felt it too, and it wasn't there with my classic. The system is apparently doing more than simply moving pistons. It might have something to do with the secondary coolant circulation. After the head of the engine is warmed (using the coolant stored in the thermos), the remaining hot stuff if flushed to the lower part.

JOHN

texassalsa04 · January 2004

that is an interesting piece of info. Thanks. I'll test it out tomorrow morning. I will probably shut down the "Auto A/C" mode completely and just run the fans on low to see if this is it.

If "Auto A/C" is the cause, I wonder if it will do the same in the summer time when I run the A/C to cool the car down? Hmmm...

john1701a · January 2004

Don't forget that motor & invertor have a cooling system. Fluids continue to be pumped through/around them regardless of whether or not the engine is running.

In my classic, I could very clearly feel when that pump shut off. (In my 2004, it's hard to tell since I haven't driven in any warm weather yet.) A cycling operation when it's needed could easily produce a feel too.

JOHN

texassalsa04 · January 2004

...my battery charge display typically shows 1 to 2 bars below full so I don't believe it's due to low battery capacity.

Personally, I don't mind the lurch and other quirks of the Prius as long as it is not detrimental to the car.

On another note, soon the Lexus 400H will be released with HSD, I wonder how much of the quirks Lexus buyers will be able to stand since they are "luxury" minded people. Lexus are known for quiet and smooth operating vehicles. I would think that 400H buyers will be even more picky with their high dollar SUVs than we are with our Prius. I would love to peek into a future 400H forum and have a look at what they have to say about their purchases...

hans000 · January 2004

The battery was 3/4+. ICE not running for sure. A house window AC unit shrudders. It's electric.

It's a rocking motion like the compressor is going through on-off cycle every few seconds. Also possible the compressor was running very, very slow. It must also happen while driving, just less noticeable.

========
midnightcowboy wrote:

The Air Conditioner doesn't run off the engine so there shouldn't be any shuddering under the normal sense of a belt drive air conditioner.

The only thing that makes sense is that it draws enough current that it causes the HSD to go into a battery charge mode.

hans000 · January 2004

The battery was 3/4+. ICE not running for sure. A house window AC unit shrudders. It's electric.

It's a rocking motion like the compressor is going through on-off cycle every few seconds. Also possible the compressor was running very, very slow. It must also happen while driving, just less noticeable.

========
midnightcowboy wrote:

The Air Conditioner doesn't run off the engine so there shouldn't be any shuddering under the normal sense of a belt drive air conditioner.

The only thing that makes sense is that it draws enough current that it causes the HSD to go into a battery charge mode.

texassalsa04 · January 2004

I've seen a picture, not high res, of the 400H speedometer and it has what looks like a traditional analog gauge. The Tach has been replaced by a "juice" meter, showing how much electrical current is put back into the HSD system while you are driving, etc.. it also looks like an analog gauge. I have also seen pictues of the instrument cluster for the Highlander and it does not look too bad. I did not download the pics because they were not high res types.

backy · January 2004

The traditional meaning of a "beta" version of a product is a product that is functionally complete, but may have some unresolved quality issues--including a partial implementation of a rarely-used function. The purpose of a beta test is to test the product through a controlled, actual implementation, and also to allow customers to get a preview of an upcoming product. Based on that definition, there is no way the '04 Prius could be a "beta" version of the 400h. The two vehicles have some similarity due to the design of their HSD systems, but are unlike each other in so many other ways that they are clearly two distinct products--one could not be the "beta" version of the other. However, I would venture an educated guess that Toyota did have "beta" version(s) of the Prius (I mean the "Classic" version) running around before the vehicle was offered to the general public. Perhaps someone (like John) who knows more about the history of the Prius could comment on that.

nippononly · January 2004

happened to get one of these as a rental, and have had it for a couple of days. I can see the big steps Toyota has made with this model versus the first one. As before, my mileage is well below the EPA rating, but I am not surprised. I have done better than the old car, however, and seem to be getting about 46 mpg - 400 miles so far. What are owners averaging in regular round-town driving?

If I were to buy one, could I put larger (205/60) tires on it, or would there be issues with the power steering unit, or tires not fitting in the wheel wells? I am aware that larger tires would reduce fuel economy.

The only thing I didn't like in the first one that has carried over is that all the climate controls and the radio display are incorporated in the NAV screen/HSD display. I wish they would have a regular radio at least - I change the station a lot!

But wow! This one is a lot faster than the "classic"! And the brakes have smoothed out a lot. It is more like a high-tech transportation pod than a car.

john1701a · January 2004

Back in 1999, a few of the Pre-Classic models were shipped over to the United States for evaluation. Toyota changed quite a bit as a result, a whole collection of tweaks in addition to improvement in the hybrid system itself (engine, motors, and battery-pack).

Anywho, the public in general wasn't involved with any of that, just selected tester families and automotive experts. The intentions were to make it as acceptable as possible for "joe consumer". So things like "should the gear-selector be mechanical or by-wire" had to be considered and "how detailed should the information on the Multi-Display be" are what had to be considered. And now, it's little things like that they are re-evaluating again.

HSD is well established. Prius broke that ground back in 1997 when sales began, and it has provided the real-word data ever since. Estima (only available in Japan) jumped in 1.5 years ago to provide real-word data about hybrid implementation for 4-wheel drive. So all the system aspects are totally covered.

What remains now is the interface research. What do SUV owners expect from a hybrid? What do LUXURY owners expect from a hybrid? What do owners that want all the technology hidden expect from a hybrid?

It basically is just plain old marketing stuff to deal with now.

JOHN

dc8527 · January 2004

"nippononly wrote: "...seem to be getting about 46 mpg - 400 miles so far. What are owners averaging in regular round-town driving?"

My first 1,200 miles in Minnesota in the past month averaged about 40MPG. The drive between my home and work is similar to EPA's test conditions with 2 exceptions, 5.5 miles, about half of EPA's distance and low temperature, mostly around mid teens above zero F. I got only 33MPG this morning. The temperature was about 20F.

Toyota said its engineers were investigating into the low MPG concern from the cold climate. The answer would be due by mid Jan. It is about time to call them again.

nippononly · January 2004

I am in California, a lot warmer here, so my mpg is bound to be a bit better than Minnesota! Also, I am judging by gas put in, not the computer, which I figure may be inaccurate - it bounces from 13.2 to 99.9 on a regular basis! :-P

What's with the gas gauge, BTW? I have stopped for gas twice (after 200 miles each time), because the gauge is down near 'E'

Does anyone do what I have already done twice - reach for the gear shift in the dark and flick on the wipers by mistake?

So no-one has thought of changing out their tires for bigger ones yet? The OEM in my case are Goodyear Integritys - not the greatest type either.

texassalsa04 · January 2004

...well, I did a test this morning in my Prius while driving to work. Temperature outside was about 49F. I had the "Auto A/C" off as well as fans/blower in off position. The lurching continued as usual. So, fromt this non-scientific test, I would say that the lurching is not due to having the heater or fans on etc...it must have something to do with what John had posted earlier...hot coolant pumping through the engine warming it up etc...

hybriddriver · January 2004

I've been doing some research on cold weather fuel mileage and here is what I found. This following article can be found at http://www.startribune.com/stories/435/3799559.html
<Start of Article>
When it's colder, engines use more fuel because they're running richer, meaning a lower air-fuel ratio (higher percentage of fuel to air). When engines are cold, a percentage of the vaporized fuel condenses into liquid form on the cold metal parts of the induction system, such as the intake manifold runners, intake valves, pistons and cylinder walls. The colder the engine at start-up, the higher the percentage of fuel that condenses on these parts.
This condensed, liquid fuel cannot burn. Only fuel in gaseous form can be ignited, so on cold starts the fuel injection system must deliver a richer mixture so that enough fuel in vapor form reaches the combustion chamber, where the spark plug can ignite and burn it.
As the engine warms up, less fuel condenses as internal parts warm up, so the fuelair mixture can be leaned out progressively. But of course, during the several-minute warmup period, the mixture will be richer than normal. And in the three-mile drive, it may well remain somewhat rich the entire time. In 0 degree weather, it probably would take more than a short warmup period and three-mile drive for the engine, coolant and oil to reach full operating temperature, and fuel-air mixtures to reach optimal levels. <End Of Article> This explains why the Prius has a thermos behind the left front headlight that can keep the coolant warm for up the three days. So why still the bad MPG? Well, if you go to http://www.swri.edu/10light/mile.htm
they say that cold air is denser, so more fuel is burnt in the ICE, this denser air also offers more air resistance, and the denser air in the tires reduces tire pressure. So all of this explains why all cars get less MPG in cold weather. However, this still does not explain the extraordinary poor MPG performance of hybrids in cold weather. I've lived and driven where it is cold and snows and never really noticed a big hit in MPG when it is cold with a pure ICE. I always checked my mileage after fill ups so I would have noticed. So why the acute affect with hybrids? Well, if you go to http://chemistry.about.com/library/weekly/blbattery.htm
someone with a Ph.D. in chemistry explains that if a battery is used at a low temperature then less current is produced than at a high temperature because the chemical reactions inside the battery slow down. Since power(watts) = volts multiplied by current, if you have less current, then you will have less battery power. Therefore, the gas engine will have to work harder and MPG takes a dive. This is why on the HCH there is a vent behind the back seat to allow warm cabin air to flow on top of the battery pack. However, there is no fan to blow this warm air down over the battery pack and so it stays cold. This explains why HCH drivers also report poor cold weather MPG. Perhaps someone who lives somewhere cold could perform an experiment by somehow rigging up a contraption that will keep the battery warm and then drive it on a known route to see if it makes a difference. If we can solve this problem the data can be sent to both Toyota and Honda so that they can develop their own battery temperature management systems. If successful, perhaps some kind of after market device could come out of it for existing hybrids?

john1701a · January 2004

> battery is used at a low temperature then less current
> is produced than at a high temperature because the
> chemical reactions inside the battery slow down.

The sweet part of the Toyota design (not sure about Honda) is that it bumps up the voltage to 500 via an invertor. So even if you aren't able to draw as much from the pack due to the cold, you'd never notice. Power will remain the same, regardless of temperature. Overall capacity will be lower though. Fortunately, the pack is big enough to compensate for that.

JOHN

hybriddriver · January 2004

> it bumps up the voltage to 500

But what if it is so cold that it has to go above 500 volts to maintain the required power? 500 is the max. A better system would have been to keep the battery warm. Then there would be no decrease in power or capacity.

hybriddriver · January 2004

> it bumps up the voltage to 500 via an invertor. So even if
> you aren't able to draw as much from the pack due to the
> cold, you'd never notice. Power will remain the same,
> regardless of temperature.

The given power(watts) that a battery pack can deliver at a given temperature is fixed. Since power(watts) equals voltage multiplied by current, then if power(watts) is fixed and volts goes up, then current must go down. This is the law of conservation of energy. You cannot get something (more power) from nothing. If you could, then you could multiply your voltage with an inverter to a billion, billion volts and power the entire world! I don't think so. The Prius has an inverter because the battery pack puts out DC current and the motor is AC.

coolguyky7 · January 2004

Did you get rid of the Matrix for the Prius?

nippononly · January 2004

this is a rental that is due to go back soon.

But the Matrix may go soon, possibly to be replaced by something other than a Toyota for the first time in seven years.

This new Prius is really neat in many ways, but I have decided it isn't really my thing - not in the market for a Camry-type vehicle. But I was curious to see all the improvements over the "classic" Prius, since I accidentally rented one.

Toyota Prius

Comments

Helpful Tools

Most popular vehicles