Prius are Fuel Efficient my Butt!

It's all horses for courses..

The Prius works well as a (very) short distance commuter car. The fact that Toyota made the mistake of making it a petrol rather than a diesel hybrid highlights some of the other shortcomings.

Don't get me wrong, I treat Prius's on the road as rolling chicanes, because they are always driven by people who seem either lost or oblivious.

One of the fellows at work owns/drives one and swears by the economy but he only drives 15km (about 10 miles) a day. Where as I have a slightly longer commute of around 90km (55miles) with both urban and freeway running. My 740 Volvo does around 9.8l/100km (somewhere in the 24-26MPG). It sorta works out, based on what he tells me, that I'm actually in front on a extrapolated comparison.

That is not taking into consideration that there is little love for a second hand Prius, there is one that was traded in in a local car yard, 3 years old and a 1/3rd of the new price. It's been sitting there a while too, must be fear of the cost of replacing the batteries that makes it a ownership liability.

I suspect once these cars first service life is up(about 7 years), they will just go straight to the scrappers and not be parted out. Where as my 20 year old Volvo will still be worth some money and be a viable car in ten years time.

The Prius is a "Green" vanity car no more no less, a nice niche marketing tool for Toyota to offset its other less "Green" products. And for the GW/CC Leftards to salve their corrupt consciences.

Would I consider a hybrid vehicle? Only if it makes financial sense and Prius's (at least in Oz) doesn't. Also it has to be the right technology hybrid, "Bn" diesel electric hybrid makes some sense but not petrol or gas(LPG/CNG) electric.

Right on, I need to impress myself with comfort, cost, and my aging body's needs, not some greeny.

If you want a very efficient very reliable car, a reasonably well maintained VW with the TDI engine made in the last 12 years is unbeatable.

TDI still on the road with over 400,000 miles is not uncommon. Unmodified decade old TDI Jettas and Golfs typically average over 40 mpg for combined city/highway driving....normal non-hypermilling.

Mpg in the 50s is attainable with only minor modifications.

BBB

Go hang a salami, i'm a lasagna hoG

In the late 80's and 90's I drove a 5 speed Ford Fiesta and then a 5 speed Ford Festive.

Without using any hypermiling tactics I achieved over 40 MPG during the summer months. (I kept track on the mileage and gas and did the calcs).

My children learn to drive a straight stick and didn't have to pay so much for gas.

I'll second redfred's comments. The Prius does very well at what it was designed for: city driving.

I have a friend who owns one and in a trip along I-95 a while ago, we hit 50 mpg. This was mainly due to the stop and go traffic we encountered through Baltimore's tunnel. Had it been a smooth drive all the way, we might not have done so well. In any other car, even a VW TDI, the mileage wouldn't have been nearly as good.

As for Prius drivers, my friend is the odd man out. I'll agree that most of them drive like grannies. The Prius improves their mileage despite their poor driving habits. Unfortunately, their poor driving habits cost me in mileage. e.g. crawling up a hill forces me to do it in low gear.

''...We hit 50mpg....mainly due to stop and go traffic...''

Care to elaborate? It sounds like you are of the opinion that stop and go traffic condions improve mileage when driving a Prius.

Really????

In a Prius if you're not moving the gasoline engine is not running.

This does not equate to stop and go traffic conditions being more conducive to higher mpg than constant speed driving.

a prius cannot recover all the energy from decellerating and convert it into electricity. What portion is recovered is stored by the batteries at less than 100% efficiency. When it is time to reaccellerate, the batteries will not return the charge with 100% efficiency, and the drivetrain will require additional input to overcome internal friction.

During the period stopped when the prius engine is not running, the people inside will still be running....the air, and the stereo, and several lights like running and brakelights, the engine will work harder later to recharge the battery.

...most of all, when stopped, no miles are beig contributed to the 'miles per gallon' metric. Stop and go traffic should be a condition understood by engineers to be a challenge to efficient travel.

While a prius may do well compared to other vehicles in stop and go traffic, laws of thermodynamics still apply and it will not get better mileage by costantly decellerating then reaccellerating instead of carefully maintaining a comparable constant speed.

Quite true however, in the most commonly found conditions of stop and go traffic the peak speed is only a little bit faster than the designed ideal velocity to maximize fuel consumption. (This optimized velocity is slightly different for every car design and I do not know what it specifically is for the Prius.) Where highway driving despite the lack of stopping consumes more fuel per mile/kilometer from the higher drag components. In other words if one chooses to drive non-stop at 35 MPH, you will get better gas mileage than if you drive non-stop at 70 MPH.

So if one wanted to take a Prius to a test track to measure the city driving numbers by repeatedly accelerating up to 90MPH and quickly braking to a stop so that the actual average velocity was 45 MPH you will not get as good a gas mileage as driving at a constant 45 MPH and you will unlikely get close to the rated city driving numbers. But by strategic use of gradual deceleration in real stop and go traffic a hybrid engine will give better gas mileage than just a conventional engine.

We are getting closer and closer to to being in complete agreement. I think soon we will arrive.

My original comment was essentially a protest voiced concerning the implication that stop and go driving aides fuel economy in a Prius.

Whether the statement was based on a significant yet common misunderstanding of hybrid technology or was simply poorly worded yielding an unitentional attribution error (while stop and go driving often results in low average speed, it does not improve efficiency any more than the combination of wearing pearl earrings, not being being able to see over the steering wheel and having blue hair would improve efficiency); we both agree that the statement in original form left much to be desired.

The example you provided was solid, if exaggerated somewhat to favor your perspective.

One needn't have the Prius accelerate to 90mph and brake to zero, for steady state 45mph to have clear advantage in efficiency.

Driving a steady 45mph will be much more efficient even when realistic stop and go conditions exist. A steady state 45 mph will be more efficient even compared to driving at a speed that continually oscillates between 5 mph and 45 mph at a relaxed rate of two completes cycles per minute (so every 30 seconds the car would reach 45 mph and begin slowing to 5 mph).

In this example, the stop and go driving never exceeds the steady state driving, yet although the average speed is lower than (and top speed the same as) the stop and go driving, the efficiency will be inferior to the steady state.

No matter how far below the steering wheel the driver's head is positioned; no matter how long they stay in the left lane with their right blinker flashing; no matter how blue they have appeared to have died their 1940's style hairdo; the incessant need to frequently mash the brake is not going to improve mileage over steady state constant speed driving.

I did use some hyperbole to make the point that stop and go use of a hybrid will not necessarily improve fuel efficiency. But I thought that my hyperbole made it obvious that stop and go on a track is not the common meaning of the terms stop and go. The most common usage of this phrase I find to mean the complete phrase stop and go from traffic congestion. Now the frequent but the mostly gradual starting and stopping that happens in traffic congestion does increase the fuel efficiency of a Prius versus flying down the highway at well above the optimal continuous speed "sweet spot". So I say that it is still valid to say that a stop and go will improve the efficiency of a Prius. Yes, an optimal operating scenario will exceed stop and go efficiency but people do not try to drive in the most optimal mode of driving with any vehicle unless they are looking for a gas station.

So I am not the only one who finds the Prius efficiency rating a bit contrived.

If the engine is supposed to be so fuel efficient then where is that added efficiency disappearing between it and the wheels? Does charging up that battery at road speeds take that much away from it in order to gain the little added efficiency during in town driving?

To me engine efficiency means nothing if it doesn't show up at the gas pump. So what I am saying is if a car weighs 2/3's what a full sized car weighs and is 2/3's the size and has half the aerodynamic drag plus on top of that has an engine that is supposedly twice as efficient as the average car then why does it only get 50% better fuel economy than the bigger car does when subjected to the same driving conditions and environment?

For what its worth I found my aunt and uncles in town mileage numbers to be suspicious as well. I only had a limited time of around an hour of in town stop and go traffic driving though Minneapolis while we picked up a relative but the whole time we did it I never saw the mileage rating meter go above the low 20's.

Well let me first make the cop-out excuse that maybe you had a limping failure that was eating power. (Dragging brake shoe, failing battery cell) More than likely while you were in Minneapolis the low 20's values you cite came from a random sample views of the computer display when traffic permitted safe inspections. At those instances you were getting low 20 MPG from the system.

Toyota made a variety of compromises in making this vehicle. Just like every engineering design! Now how this hybrid improves efficiency is not from the fossil fuel burner always operating in the volumetric efficient part of the power/torque curve. This is how some diesel electric locomotives work and require a lot of batteries for starting and stopping to be practical. This hybrid improves efficiency by allowing some of the energy removed from braking to be saved in the batteries. You charge the batteries while braking. So charging the batteries while moving is not what happens. Batteries have a much higher energy density than capacitors but the power density (energy/time) is not as good. So rapid braking does not transfer as much energy to the batteries for reuse in the next acceleration cycle. I suspect that rapid braking may even damage a few battery cells. I can also easily think of some circuit designs that can prevent damage from happening. Probably Toyota included a similar circuit and my worries are unfounded.

Regardless of these nuances, anyone can sit down and immediately drive a Prius. A Prius though is much more susceptible to driving habits affecting fuel efficiency. To approach the maximum city fuel efficiency, one must drive a Prius slightly differently than a non-hybrid vehicle. This difference is one of the pivotal reasons that Toyota installed that big graphic display so people can play the Prius game. Many Prius hackers dislike the decisions that Toyota made on the crossover points from electric to gas. The six Prius hacker friends I have are evenly split on should the changes between power sources be sooner or later. (Sounds like Toyota split the difference) One friend that switched out the battery pack to all NIMH instead of the original LI-ion batteries. He also changed the power crossover so that more electric motor work was used and is already on his second set of NIMH batteries after 3 years. He claims about 60 MPG when he doesn't include his power grid recharging cycles.

I see. So for me who drives everything basically the same it gets basically the same average MPG numbers of most any other car in its size range.

But if I play the 'Emperors new cloth's' game and drive it as such then it gets closer to the millage numbers its claimed to get. Unfortunately if I drive my other vehicles in similar ways they too also could get much higher MPG numbers than they average as I drive them now.

Pretty much. Some of the driving techniques that maximizes a Prius, like long term gentle braking, don't help as much in a regular vehicle but they do help a little.

I recently purchased a high mileage 2005 Bonneville SLE with all of the toys for work type road trips.

I paid $5700.00 for it and I could easily triple my money parting it out.

On my present trip of 1200 miles, I got about 24 miles to the gallon with normal Interstate driving, but, oh the comfort. No achy muscles, sore joints, or banged heads for this portly guy.

Sure the toy cars look cool, I have a Honda Accord too, that puts me in an achy and sore funk after 200 miles and gets better MPG, as I am sure does the Hybrids.

I tend to be negative on such cars as in comparison here in Europe, we have so many compact and larger cars with tiny fuel consumption AND NO EXPENSIVE BATTERY TO REPLACE.....

My car is not small, 6 seater, 2.0TDI can pull 2 tons legally and gets around 33MPG easily (40MPG UK Gallons).......of Diesel......

....and there are plenty more cars around with even lower fuel consumptions.......mine is nowhere near the limit!!!!!!

So I steer away from battery assistance.....

For a townie with short runs and no IC motor usage, is the Prius fine......

PS. What does a new battery set cost by the way????

That rather adds to the running costs......

Do you know roughly how often they need replacing.....?

WOW, plus recycling fees, I am sure.

I bet only a few salvagers will accepted a damaged or totally worn out battery.

Do not base your opinion of a car based on one vehicle - manufacturing tolerances can cause some very surprising outcomes. We had a 1987 Cougar with a 5.0L V8 engine that would get over 30 mpg on a trip and around 26 mpg on average. This was way above the claimed figures. This is the extreme tolerance match up to the good side. Usually it goes the other way. This engine was torn down at 105000 miles and reassembled as it was, as wear was negligible. It is still going strong in my sons bracket race car.

My current car, a Chevy HHR struggles to get 21mpg, while a neighbor up the street 1/2 mile gets over 30mpg from hers. Some are just built better than others.

You may have experience with a car that is on the very poor side of tolerance match up. Test a few more, then condemn the whole lot if indeed the mpg is not as expected.

I'll keep my raggedy '94 dodge cummins with 300K+ miles and 22 mpg...

paid for itself over and over again.

plus it'll continue to run with no batteries and no alternator ( I can prove that easily)

I wish some actual Prius owners would reply to this forum thread. I personally do not own one but I rent them all the time now. I'll share my experiences, which are a complete opposite of what TCMTECH experienced. I wonder if it has anything to do with what model year it is you drove. I drove my first one this February from Lascassas, TN to Boston, MA in a 2010 Prius hybrid and I averaged 49mpg going up there and coming back. We had 4 people in the car the whole way Which was myself my wife and our to boys which were 13 and 15. We also had two large full suitcases and two small suitcases. All of our inner city city driving we still averaged 44-45mpg. Other trips have been from the Manchester airport in NH to Portland, ME and I had another 2010 prius and seriously thought it was going to top 50mpg but I still averaged between 48-49mpg. Another trip was from Raliegh/durham airport in NC to Concord, NC and still I averaged 48-49mpg in a 2010 Prius. I have been able to get a 2010 model on every occasion except once when they gave me a 2008 model and it still averaged around 46-47mpg. Now this was my averaged mpg for highway, city, and other stop and traffic. Now was I a bit more fuel economy concious while driving the Prius, maybe but let me tell you while I was on the highway or the interstate I was definitely taking the speed limit to the max. I never hypermile and personally I would like to strangle poeple that do. I hate the TCMTECH had a bad experience with the prius he rented. Better luck next time. I'll continue to rent them until I actually buy one myself. It cost me roundtrip in fuel for our Boston, MA trip $120. We drove a total of over 2400 miles. Again, I'm sorry you had a bad experience with the mileage you got out of the prius you rented. I however, shall continue to rent them and enjoy the very cheap fuel price. It cost me around $28 to fill a completely empty tank and while on the MA trip we were averaging 480-500 miles per tank of gas. Long live the Prius and I hope all of the other car manufacturers get on board and make a car just as economical. Come on "Ford", I believe in you!

Thomas G.

You're the reason why the rest of us are driving Prius' and Hybrids.

tcmtech: "But to be fair I did strip the emissions systems out of it when I got it which provides the added gains in fuel economy."

Now ask yourself which vehicle pollutes less, a Prius, a Mercury Grand Marquis, or your modified 1994 Mercury Grand Marquis?

I am one who could care less about the perceived level of pollution that something produces. The driving factor with the quest for more efficient vehicles for most people is most often not how clean their tail pipe is but how little they cost their owners for fuel.

If you have ever read my many posts on threads related to vehicle fuel efficiency or emissions related subjects you would see that I am very open about the fuel mileage gains that getting rid of that politically imposed emissions system crap can have. Every vehicle I have ever owned has had at least some if not all the emissions systems bypassed modified or entirely removed. I have also helped many family and friends do the same modifications to their vehicles too and continually offer many tips on such sites as this to how others can do the same emissions system modifications/removal with their vehicles as well.

So just be careful about what tree's you hug when I am around with my chainsaw!

A Prius,I thought they did away with them when they did away with the Edsel

I own a Prius it is two years old. I drive to work and play in Fort Lauderdale. Traffic here is never fast and is commonly stop and go. The mileage is an impressive 50 MPG+ for this use. When I drive to Tampa my Prius gives me about 40 MPG. It is comfortable and quiet. It is what I expected it to be. My other vehicle is a 4x4 Ford F-150 which yields about 17 MPG. The Ford will tow a boat with ease and carry anything I can pile into it. The point is that both of these are excellent for thier purpose. My 1965 Honda 150 (CA95) gets better than 90 MPG.

It is better to match your vehicle for your purpose. The old couple next door has a 1984 Ford Crown Victoria that gets 22 MPG and they love it. The engine was modified around 1995 when they replaced the engine and transmission at a local Speed Shop. That engine has 300,000 miles on it. My guess is they have spent less per mile than any of us.