Hybrids, not as great as we thought

You may be thinking a recent Consumer Reports article that seemed to show that the extra cost of a hybrid is not recovered in fuel cost savings.

With respect to the Toyota Prius, Consumer Reports just issued a retraction saying that they erred in their calculations and that, indeed, over a number of years, a Prius does save more in fuel costs than the extra cost of the initial purchase (taking into account tax incentives, etc.).

Other than that, the fuel economy figures (hybrid or standard) determined by US DOT testing have long been known to not reflect the true world. In fact, DOT is changing the test to better reflect the average person's use of the car.

Also, it is important to keep in mind that cars like the Prius are designed to provide fuel savings when driven in city traffic, NOT on highway driving. So if you use a Prius mainly in the city, you will probably be impressed with the fuel efficiency, but if your driving is mostly on the highway, you will be less impressed.

Merritt

What 'we' is that? Toyota thinks they're great because Toyota sells cars and they're a hot, profitable item. It's that easy.

The marketeers that are pushing hybrids gloss over the fact that they only get better mpg with a lot of stop and go traffic, in city driving. Indeed, the Priuses electric motor shuts off over 50Mph I believe it is. If your commuting is mostly highway miles at constant speed, their mileage is no better than a comparable conventional engine. But if your a soccer mom doing a lot of city driving then indeed the fuel economy of a hybrid is much better.

The other problem is that the other manufacturers that are introducing hybrids are basically putting larger, more gas hog engines in them, and using the hybrid technology purely to meet CAFE requirements, as a result you get more horsepower for the weight of vehicle, but no net fuel savings.

Ted

You guys are Spinning out of control. Fact is both power systems work in tandem all the way to top end, which in my case is 101 mph. mark_

To a point this is true. However, I found if you spank the car up to passing at 94 mph the thing gets there and right now. Reminds me of those electric slot cars that fly once the trigger is pulled. The electric motor does kick in and you can fell the G's. Passing is far quicker than the old Saturn. Highway high-speed mileage has been approximately 39 mpg for me (excess of 85 mph on I-5) -- far better than the old dinosaur we had. Our fuel card bill has gone from over $180 per month down to about $65 or so.

Check out the Toyota Volta:

Volta's claim is 0 to 60 in 4 seconds with a 31 mpg mileage claim, compare that to any other performance ICE sports car (excluding the price tag though!). One electric motor for each wheel along with a V-6. Pretty impressive performance and mileage. Basically, a slot car for humans.

B~

Agreed. A modern hybrid is a complex beast, with business going on inside it that most people never dream of. For example, the big savings are not due to the electric motor or the regenerative system, though they play their part. The Miller Cycle engine is more efficient than the common Otto Cycle unit, so running on it alone is your best way to save and the onboard control system is well aware of that. The electric subsystem is there to augment the petrol engine when required, such as at speeds lower than the petrol engine could handle, or at odd moments at higher speeds.

(This is covered by past posts; try Googling for "+prius +miller" in this NG.)

The dashboard mimic diagram is educational. The electric motor and generator are constantly switching on and off in a frenzy of activity, even at high speeds. Meanwhile you just drive along.

It's nothing but eye candy designed to sell to people who want to focus on the technology of the car rather than just driving the damn thing.

What you say Elmo could be true. I know if you are behind a Prius and your eyesight is good you can invade the privacy of the Prius and see clearly not only the top dashboard odometer but the graphic chart below and tell how well the car is doing. mark_

No, it gets better gas mileage too, especially around town.

It may not make economic sense (yet) but it's probably pretty close.

If you drive 20,000 miles at 45mpg instead of 25, that's a savings of

350 gallons or almost $1,000 per year. It's about 5-10K more expensive depending on which car you're comparing it to (Camry or Corolla...it's prob. more comparable to a Camry).

And no, the battery doesn't cost 8K and need replacing every 100K.

OK that's one way to look at it. Another way is to look at the cost for filling up the Camry (800 gallons X $3 a gallon = $2400 a year) and the Prius (444 gallons X $3 a gallon = $1333). You see, once you sign for the car the extra money is forgotten. But with the other car you're reminded every time you fill up. Actually, when I get in a Camry or Corolla I hit my head unless I bend my neck down real close to my chest. Not good. And the engine's after all these years still have that damn tap tap sound that drove me nuts when I was a teenager. No thanks.

Aside from the fuel savings that hybrids offer for city drivers, another benefit is that because they use "regenerative" braking, the brakes on hybrids wear less vs. conventional cars. So hybrid owners will spend less money on brake repairs and replacements. A while back, I analyzed my records for a Camry I've owned for a long time, and found that I'd spent more on brakes than any other type of car maintenance - more than shock replacements, timing belt changes, etc. I suspect my experience is typical, too.

I posted a question about brakes on hybrids back in December, and here's what one fellow noted:

"As an interesting side note, the dealer I work for has ONE recorded case of replacing brake pads on a Prius. I've seen some with well over 100k miles and over 50% of the pad lining remaining."

Battery life for most batteries, barring abuse, is age-dependent.

Ted

But, where does the electric motor get the energy from? The battery, and where does the battery get it from?

If the gas engine and electric motor are constantly alternating as to which one is powering the car, like another poster claimed, then that would be horriby inefficient at highway speeds where you NEVER BRAKE. The reason is that you would have the gas burned in the engine being converted to mechanical energy, then to electrical energy, then to chemical energy, then back to electrical energy, then back to mechanical energy. All those conversions waste power since you lose energy every time energy is converted.

Your spanking the car, in order to have any net gain from the system, would have to use energy gained from regenerative braking that happened earlier. Once you spank the car enough times, unless you slamming on the brakes every time you finsh spanking it (a pretty unsafe method of driving on any highway in my opinion) you would use up the reserve energy in the battery that had been gained by prior braking, and then your getting all energy from burning gasoline, regardless of whether some of the energy detours through the battery and motor-generator.

Who really gives a rip about that and how is it germane to a discussion of fuel mileage?

I don't doubt that, but your comparing apples to oranges here. For starters you have a new engine compared to an engine with a few miles on it, you also have weight differences, and the engines are constructed internally differently.

To really make a comparison what needs to happen is someone needs to take a Prius, drive a couple months with it in city, and a couple months in it with highway, and record both mileages, then disable the traction battery, and repeat the driving pattern. That would really tell everyone exactly how much MPG is gained by the hybrid system, instead of these rediculous comparisons to other cars that people seem to make.

I could run comparisons of mileage of a Moped with a SUV in city driving and claim, based on the results, that the Moped engine is obviously superior. Everyone would laugh at that. But nobody seems to think it just as rediculous when people compare Priuses to Corollas and such, yet this is exactly what is happening.

As the question, why didn't Toyota come out with 2 models of Priuses, with exactly the same engine except for one difference - one model was a hybrid, the other just the gasoline engine only. I'll tell you, it is because it would make it rediculously easy for the general public to make a true apples to apples comparison and what would be discovered is that hybrid technology is overblown, and is really of only use for city driving where there's a lot of braking. That would have taken the wind out of the Toyota hybrid sales effort which is why they didn't do it. So now we are stuck with a lot of people hand-waving about superior engine technology and alternating engine/motor complexity and ignoring some simple logic because it's not convenient.

I would be a lot more impressed if Toyota actually came out with a vehicle that had the electric motor for each wheel and NO V-anything, and an electric cord to plug it into the garage outlet to charge overnight. What we need is to get off the gasoline-as-motor-vehicle-fuel kick entirely, not to just make the vehicle more fuel efficient.

You can argue all you want about vehicle efficiency but I could build a stationary electric generator that ran on gasoline which had an efficiency rating that would kick the shit out of the best efficiency rating of any vehicle gasoline engine Toyota could produce.

Ted

You'd understand it better if you stopped being a spectator and drove one yourself for awhile. Fact is the motor gets it's energy simultaneously from the engine, and other times directly from the battery, and othertimes both from the engine and battery. The battery is refreshed either by the engine, regenerative braking, or simply by letting up so slightly off the accelerator pedal as you would do on a decline. Part of your hypothesis is true in that if you keep punching the accelerator the battery will drain (and it shows it on the chart) but once your driving speed levels off the engine is producing slightly more energy than is needed so the excess is returned to the battery. And yes, even at highway speeds there are times neither the engine or motor are running and the battery isn't charging. If it happens just for a moment or two it's possible the car traveled 500 feet on momentum alone. One doesn't have to do an elaborate test to find out approximately how much improvement there would be over a non-hybrid Prius if there was one. But I'll leave that up to you to find out when you decide to stop being an armchair warrior.

mark_

Mark covered most of the response. Add to it, the ICE is 18% efficient overall in power delivery with all the losses through the engine and powertrain. Anything added to increase the efficiency of the ICE engine and better transmission of the Prius makes it more efficient, or better mpg in this case.

So it gets spanked once in a while for passing. It makes up for it during slowdowns or braking. What does yours gain back - or is it just blown out the tailpipe?

Someone mentioned they were slow.

Obviously you do.

No. I'm comparing fuel used and fuel wasted. Bills are substantially lower.

Why would anyone want to go back to ICE alone to get back to an 18% efficient vehicle? That's the point of the hybrid. I believe my credit card payments address that issue.

You could make the comparison between the Lexus SUV or the comparison. However, the features gained from the hybrid technology are more than just the dual power - better transmission design, less brake wear, more electronic features for creature comfort, and better for the environment overall (although I liked the goodies more as well as the reduced maintenance and extended service intervals more).

Since I also have motorcycles in the garage with engines small than the hybrid's engine I can make a comparison. Guess what? They "all" get worse mileage overall - both freeway and city. Go figger.

Usually by people to want to size-for-size and not feature-for-feature. Yeah, they aren't the same nor is a Highlander ICE SUV and a Highlander Hybrid the same. Gains in mpg may be small, but overall maintenance costs and service intervals are greater as is the better power of the hybrid (it was smartly touted as a improvement in power rather than better mpg performer by Toyota).

You soon be assimilated and wonder why you even wrote that.

If you check their concept cars on their website you will see they are working on it (one electric motor per wheel) and other fuel requirements (cells). Wonder who will get around to putting one on the showroom floor first: GM or Toyota?

GM may have a job for you.'

B~

Toyota probably built the Prius the way they did simply to make the best possible hybrid car that they could. And it's pretty good. As for comparisons, comparing the Prius to vehicles of similar size, weight, capacity, passenger comfort is reasonably valid.

Comparing it to a Corolla does tell you a lot about hybrid technology. In the city, it's a big win, economy-wise. At highway speeds, where drag becomes the limiting factor, it offers better fuel economy but fuel economy that you could probably approach or, possibly, exceed with a carefully designed gas-only vehicle optimized for highway use. Of course, there'd be tradeoffs. You might end up with a car which takes 15 seconds to get to

60mph.

The Prius is a decent all-purpose vehicle that offers unusually good fuel economy.

You can buy such a vehicle now. Just be sure to plug it in every 75 miles or so for 4 or more hours. That's not always convenient? Well, an electric-only vehicle is limited by current battery technology, which is why hybrids were developed. The chemical energy of 100 lbs of gasoline is much, much greater than the electrical energy that can be stored in 100 lbs of batteries, so a hybrid can be developed that travels 500+ miles on a "charge" and can be "recharged" in about 5 minutes.

Now, if I were Toyota or Honda, or any auto manufacturer, I might give some thought to making extra batteries an optional accessory and supplying an AC charger for the car. People with very, very short commutes might be able to run the current Prius hybrid as far as they need on a daily basis off the overnight charge (I could maybe do this). People with longer commutes could buy extra battery capacity and run the enhanced Prius as far as they need on a daily basis off the overnight charge (range is doubled if you can plug in at work). If the spare battery capacity was readily removable, that would be a plus on long trips or trips where you needed more room in the trunk.

To which we would say, "So what?" You won't be driving that to work.

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Ted, it really doesn't help your comprehension if you start with a misunderstanding then work yourself up into indignant hysteria.

What you need to remember is that the improvement is the OVERALL efficiency. Yes, it costs energy to generate electricty, charge a battery, drain the battery, power an electric motor. But that is not the whole story. A modern hybrid is far more subtle.

Where it can, the Prius drives the wheels direct from the petrol engine. As its fall-back (eg, at zero-to-low speeds and at odd moments) it has the electric motor. But the electric motor need not draw its power from the battery. One mode (which sounds daft but makes sense, once you understand how the drive system works) is for the petrol engine to drive the generator, which at once feeds the electric motor. AIUI, this mode is useful if certain gearing ratios are required, or to adjust the load on the petrol engine.

The business about the eletric side of things switching on and off rapidly is no cause for concern: electrons are a d*mn sight more nimble than are great lumps of whirling metal and glugging liquids; and what the frantic activity does (apart from a little housekeeping, like keeping the battery topped up) is to even out mechanical loads and speeds, thus improving OVERALL (remember?) efficiency of the system, as well dynamic performance.

Think of the _system_, not its individual parts.

Or just drive the ruddy thing.

Methinks they made it a separate model so that direct comparison could not be made. If one wants to make a true comparison of a hybrid it must be with the same vehicle. When comparisons were made by several different sources including CR, with the Highlander, Civic, Escape, Lexus etc. it clearly shows the conventionally powered twin is far less expensive to own over time. The comparison between the drive home purchase price includes the additional premium, any rebates and/or tax incentives, maintance costs, additional interest, and battery replacement. In EVERY instance the hybrids are shown to cost thousands of dollars more than the conventionally powered twin, even if gasoline should go to $5 a gallon, even worse if it does not. Any other discussion is simply opinion, not fact. If you intension is to save the world, buy the hybrid version. If you want to save money buy the conventionally powered twin, WBMA

mike hunt

Isn't that true for a lot of things, not just batteries? Try as I may, I cannot make sense of your statement. Sorry.