Slashdot Mirror
Hybrid Cars Don't Live Up to Mileage Claims
Omega1045 writes "Wired News is running a great little article about how hybrid cars (specifically Honda and Toyota models) do not come anywhere close to living up to their fuel efficiency claims. The article highlights that the EPA tests are more to blame than the car manufactures. Consumer reports has shown that the mileage for these cars can be as low as 60% of the claims. The article also links to a blog authored by hybrid enthusiast Pete Blackshaw detailing his failures getting any real answers on why his Honda Civic Hybrid isn't getting better fuel mileage. It looks like these cars are more hype than help in the battle against pollution and foreign fuel reliance."
I didn't see this answered in the article, but are other gasoline-only autos also overrated?
I mean, if the same EPA testing standardis used on all cars, and the hybrids are overrated...
That said, I have an '88 Volvo that I watch the mileage of pretty closely, and I get b/w 25 and 30 mpg. And it's a big heavy bastard...
hmmmmm....
Have quite a bit less power than their gas-only counterparts (like the hybrid Civic). I've seen people trying to drive these things like they're race cars, and that certainly isn't going to help.
MPG estimates are easy to reach when drive like a responsible person, and according to the cars manual. This is often a bit slower than you are comfortable with, hence the problem. It just happens to be that the rift between gas waste with the two driving styles is quite larger with the hybrid engine.
Drive nicely, you're mileage will be a lot better.
That CSS file that blocks ads
Absolutely correct. If you accelerate very slowly, keep that engine running at low RPMs, only drive on flat surfaces, coast whenever possible, then you might approach the published numbers. My car is rated 24/28 or something. Realistically I average about 23-24 with mostly highway driving. I think most consumers are aware of the extreem optimism of those numbers on any type of vehicle.
I had a Geo Metro with the 1.0L engine that got 55 MPG regularly. The car was a bit small, but it'd go 80 MPH on the highway.
And VW makes some diesels that get really great mileage, better than hybrid.
Hybrids also have the disadvantage of requiring heavy batteries that contain some nasty stuff. The environmental net might not be positive.
Nevertheless, the technology is still new, and I wonder how far it can be pushed.
This is America, damnit. Speak Spanish!
It looks like these cars are more hype than help in the battle against pollution and foreign fuel reliance.
If these results are accurate, then this is true, and it's quite sad. What I don't understand is why we aren't promoting Diesel engines more often.
For example, a VW Jetta TDI gets 50+ MPG on the highway. Unlike the Prius or the Civic Hybrid, diesel engines are cheap, highly reliable, have low maintenance costs, and can easily run on BioDiesel without a performance loss. Even with BioDiesel and Petroleum blends, you're still talking very little pollution in comparison to a similar unleaded gasoline engine. A full tank on a TDI will get you almost 800 miles before you need a refill.
So why as a society (I'm referring to the US here, the EU is very much ahead of us with biodiesel) don't we promote this more often? Let's reduce our foreign oil dependence, and not have a need to drill ANWR. Use Diesel & Biodiesel!
. . . the vehicles do get better gas mileage than standard automobiles. From a conservation standpoint, that's still a good thing.
As I recall, the Honda Insight is supposed to get as much as 60 MPG. Sixty percent (from the root parent) of that is 36 MPG. I used to get 30-35 MPG from my old Ford Escore (stick) and up to 33 MPG in my old Saturn L-200. (I also got up to 50 MPG from my '69 Beetle, but that was because on the highway I would cut the engine off on long, steep hills. That is another story.) And, I believe that diesels can produce up into the 40 MPG range (e.g. VW Passat). So, the "better gas mileage" is, to me, "slightly better gae mileage."
However, what of the batteries? I've been told that they may cost over $1000 to replace when they go bad, and that the replacement rate is somewhere in the ball park of one in five or so years. Additionally, I've been told that the batteries themselves are quite toxic. So, methinks from a conservation standpoint they are not markedly superior to full ICEs.
That said, my brother had an Insight and tightly tracked his fuel economy. He was fanatic about trying to squeeze very amp he could. He found his economy to be in the 60 MPG range. Most of his driving was highway (60+ miles each way to work) in a low-traffic area (Arkansas). So, YMMV. Having zipped around town in them, I was quite pleased with their pep.
What those who want activist courts fear is rule by the people.
Perhaps the Civic isn't as great as the EPA rated. I don't know, I'm not interested in one. However, Randy Rathbun's blog had a mileage log that contradicts this story at least as far as the Prius (the only hybrid I'm interested in at this point) is concerned. I trust his empirical evidence more than a poorly researched article that paints all hybrids with the Civic-brush.
mbbac
With the AC off, I get 44-46 mpg. That's lower than the calculated mpg the onboard computer gives me,m and lower than the official EPA mpg. However, I still think it's pretty good. I have some theories about why people don't get good mileage:
1. The electric motor acts like a turbo would. You can't just hammer down and plow past people in the passing lane. If you try that, you'll just shove the CVT into 5000 RMP mode and waste a ton of gas. You have to let it "spool up".
2. Most peope ride the brakes. If you chill out, you can engine brake and let the electric motor suck the power off the transmission rather than having the brakes turn it into heat.
3. Kinda like #1, blasting up to 80 mph is a bad idea because you waste a lot of gas *and* battery juice. You can ride at 80 mph, and relatively efficiently, too, but you have to let the car get there.
All that said, I'd like the car to have a whole lot more battery power for off-the-line accelerations, which takes up the most fuel, and to store more regenerative power.
Danke tres mucho, tovarishch.
Note that comparing an aluminum hybrid to a galvanized steel compact, e.g. the Insight to a "regular" car, would not be an apples-to-apples comparison since if you were to remove all the weight from the electrical system (adding hydraulic brakes) and increase the engine size to match the lost horsepower, the new gas car would be more efficient than other gas cars on the road today, and might even be better on the highway than the hybrid. (Although it really should fail to beat the hybrid in the city)
Yeah, I think the weight of the hybrid electrical system offsets the weight savings from the aluminum body.
But there are several things which really upset me about hybrids:
- I don't care what they say, sooner or later an accident will happen where the batteries are ruptured and smear electrolyte all over passengers.
- No matter what you do, you're never gonna get all the cars or their batteries back for proper recycling. People do strange things to cars. They end up in lakes or rivers, or abandoned in the woods.
- Aluminum is a difficult metal to work. Welding to the body to perform a collision repair is going to be expensive because it requires equipment that most body shops don't have - TIG welder, stock of aluminum sheet metal, person capable of TIG welding without warping thin sheet metal. Therefore, the cars will be scrapped more often after collisions. Also, aluminum rots extremely quickly in road and sea salt conditions - look at city buses, there's a reason all of the panels are interchangable with only 1/2 hour and a rivet gun.
- Complexity - either real or perceived - of the drivetrain is increased. More and more people and shops will want to avoid working on them, which will drive up labor costs for service. Therefore, because they're expensive to fix, they'll get scrapped sooner.
- Late-Life vehicles - Will driving this car be at all practical if the assist battery is disconnected? When the car is 6-8 years old and being driven around by its last owner and the battery dies, will it still be usable as a conventional car, or will it be scrapped rather than spending the many thousands of dollars a new battery will cost?
(In reality, I get about 37MPG on the highway, ~30 in the city... the car _is_ 13 years old)1970 Dodge Dart 4-door sedan, mostly stock, seats 5 full-size (6 foot +) adults in comfort, modern radial tires, Slant-6 brings the thing up to highway speed quicker than most new econoboxes. And it's made of thick, solid steel. 34 years old, gets 25MPG highway, about 22MPG city.
Moore's Law does not apply to the automobile!
Fire and Meat. Yummy.
I have a honda civic hybrid and I typically get around 42mpg.. It is advertised as 47. I think the main issue is that they are driven in 55 zones where as most of the highways around here are 65. If I drive 55 in the car, I can easily get 50mpg. The extra 10 mph can make a big difference. But what it boils down to for me, is that I get better mileage with this car than I would in a standard civic.
Now for some truth. (disclaimer I drive a hybrid) On the freeway, the hybrid system doesn't do much. It's all plowing wind and the engine never shuts down.
However in city traffic jam traffic, it shines big time. That awful creep and stop at metered on ramps and passing the wreck is usualy done with the engine off most of the time. This is where regular cars are very ineffecient. Unfortunately most of our time on the road isn't in these conditions in the USA. Now as part of the reality check, I have missed the EPA estimates by about 10 MPG. It's still double the milage I got on my last car. At current gas prices, the payback period has droped from never to something in the car's lifetime. If gas goes up more, the payback time will shorten much more. I don't regret my used Prius purchase.
I replaced a 2.3 Liter 4 cyl Ford Mustang with a 1.5 Liter Toyota Prius. Mpg went from 24-28 to 43-48 for my commute. Getting 400 miles on a tank is normal. I haven't risked running out of gas to try for 500 miles, but I've had enough gas left at the next fill to have done it.
The big savings I found for mine is as a standby generator. During an outage, I ran a TV, refrigerator, lots of lights, and chest freezer off the car. The engine did not run all the time. It would start, cycle for a few minutes and shut back down. Overnight my best guess is I used 2 gallons of gas. Most portable generators would require a refill every 3-6 hours to do the same job. At that consumption rate, I would not worry about refilling it for several days of constant running as an emergency generator. That could never be done with a conventional car.
The truth shall set you free!
YMMV is correct. Why it varies is important.
On the highway, a Hybrid engine is just a low-powered gasoline engine -- generally, the electric engine does not engage over highway travel. I say low-powered, and not under-powered, because today's engines have an obscenely high average horsepower. An "economy" car like a Civic or a Focus has a better power to weight ratio than many classic V6s. Your '69 Type 1 put out 55 horsepower, which was plenty to get 4 passengers and their gear up to 75 MPH.
As a low powered gasoline engine, you get your best economy by accelerating slowly and allowing the resistance of the engine to adjust your speed. Braking on the highway, or downshifting before accelerating, will take a huge bite out of your economy.
It's in city driving where the hybrid shines, but again, only if you drive it correctly. The big thing is to try to keep the gas engine shut off as much as possible. This is performed by accelerating slowly from stoplights and braking slowly as well (more energy is recycled by the magnetic brake when less is lost to the "backup" brake). Jackrabbit starts will be tempting, as the electric assist engine has a TON of torque, but resist it! That's the only way you'll see your economy improve.
To be honest, these driving methods will help you improve the economy of any car, especially 3 and 4 cylinder engines, where keeping the revs low and speed constant has a bigger effect than with a 6 or an 8. But the difference in economy is even wider for a hybrid. Whereas I can see an 8 mpg difference between racing to work (27 mpg)and driving casual (35 mpg) in my turbocharged I4, with a hybrid that difference could be close to 20 mpg.
The EPA drivers know how to drive efficiently, and that's why their scores are so high. You can learn to drive like this too...it's why the Insight has a momentary MPG rating right on the dashboard. The guy from AutoWeek who did the long-term Insight test said he considered the average MPG rating to be a "different KIND of performance rating," and that he made it a game to get it above 60.
Hey freaks: now you're ju
Not that the previous poster is right but you are also wrong the electricity comes from waste energy recooped from brakeing and slowing down that would normally just be released into the environment as heat.
yes I own a Hybrid Civic and only now that the summer heat here in phoenix has gone up to 100+ has my milage dropped to 37.4 MPG. before With control I could get 50 and avaraged 45. witch puts it almost right on its sticker claim of 47/48.
Paying taxes to buy civilization is like paying a hooker to buy love.
I heard (also on NPR) a few weeks ago that most of the pariculate emissions from diesel could be vastly reduced by using low (or zero) sulfur fuel. The EPA would like to have mandated the new fuel by now, but the trucking industry is heavily against it. They're going to mandate it anyway, I think starting in 2007, perhaps rolling from CA eastward.
Hybrids ARE great for city driving, when the maximum power output of the drive line is almost never required. The batteries can happily slog through traffic for quite some time without needing to run the IC engine. However, high speed highway driving, merging, and passing will often require 100% of available drive line power, this is where hybrids fall down.
Running both the engine and the electrics drains the batteries, requiring the engine to continue to run even after 100% power is not required, the engine has to run fairly hard to charge the batteries back up, and of course there is a loss of efficiency in the conversion from mechanical to electric energy. If you drive like grandma, your hybrid *might* reach the claimed highway efficiency, but at the cost of speed, merging and passing.
Just for comparison my 1992 Alfa Romeo 164s has a 220hp fuel-injected 3 litre V6, asside from the BOSCH Motronic 5.1-ML injection, it is a decidedly low-tech engine. Single overhead cams, 12 valves, 60 degree, the valve train and geometry of this engine date from the mid 60s. The 164s weighs 3650 lbs, roughy TWICE what a Honda Insight weighs. The Alfa also features leather interior, kickin' sound system, very good aerodynamics, and a top speed in excess of 155 mph. If I take this beast on long highway drives, I can manage 31 mpg. The reason? Most the time the engine is using only a small fraction of it's possible power output.
When a hybrid, or for that matter, any underpowered vehicle gets out on the highway the conditions often require the drive line to run at maximum output. No mater how lean burning or smart a fuel injection system is, it has to deliver more fuel to produce more power. But if a 3650 lb luxury/sport sedan can get 30+ Mpg why can't an 1800 lb econo car get 60+? The answer is it CAN. And without the added weight, cost and expense of hybrid systems. Hybrids are *a* solution, they are not however in my oppinion the *best* solution.
What we need are high effiency small-ish engines in the 1.2 to 1.8 litre range put into light weight, aerodynamic bodies. The results would be affordable, reasonably fun to drive and just as efficient as hybrids for most American drivers. Those living in cities may want to consider a full electric solution, or *gasp* public transportation (which is, unfortuneately not really up to snuff in most American cities). In addition, a displacement on demand system could improve the efficiency of small cars in city driving as well. Who says only a V8 would bennefit from this technology? A small 4 cyl car could conceivably be set up to idle on only one cylinder at stop lights.
Hybrids may actualy be better suited to high performance applications than high efficiency applications. Witness the Toyota Volta. The Volta is efficient because it rarely uses 100% of it's available power, and since about 50% of that power is provided by electrics, it's IC engine is similar in efficiency to that of a vehicle with 1/2 the total drive-line power of the Volta. The result is a vehicle that rarely taps it's full potential, and operates at maximum efficiency most of the time rather than maximum output.
A Call For A New Slashdot Moderation Level!
In the AutoWeek forums Tech Talk section, a fellow with the handle VP (Variable Pressure) Drive has a thread where he discusses his hybrid concept: Instead of constant RPM generator, battery, electric motor he does constant RPM air compressor, air tank, specially converted internal combustion engine.
The compressor fills the air tank. Pressing the accelerator pedal opens the valve to let air from the tank fill the cylinders in the engine, generating torque just like any other car engine except without combustion. Pressing the brake applies braking to the tires and also automatically closes the valve from the air tank.
He said about one minute of hard acceleration would drain your air tank completely and would require about ten minutes to refill the tank to a drivable level, but nobody keeps the throttle wide open for 60 seconds straight.
The concept strikes me as brilliant, although I am neither a physicist nor engineer so this is an inexpert opinion. The air tank should suffer less inefficiency of power transfer than a battery.
I posted this as a response to someone else, but I thought the idea was worth repeating.
Since my work is researching HEV's and I keep pretty well up to date on the tech, I might have a point or two.
HEV's are a passing technology an interim beast which really is already out of date. They never would have existed if the numbers had been balanced. HEV's in battery storage cannot be more than about 10% thermally efficient. That's pretty rotten considering that they must do that downside of the engine efficiency. They do have the advantage of allowing Electricity to charge them up when parked. The energy efficiency issues hit this too.
There is a far better technology coming right away. It is a Fuel Reformer/Fuel Cell combo. It has all of the advantages of storing braking energy etc and none of the difficulties with batteries etc that correspond in scale to the Prius etc.
Military interest in Hybrids is related to dual use of the generator. There is also stealth.
I expect that a civilian buying a hybred thinking they are saving energy or getting a good deal is going to get stuck. The technology just isn't that good. There are exceptions to this. If you are a route driver like a mail currier you will win with a hybrid. If your commute is a lot of stop and go stuff with long periods of stop or very slow driving, it pays off. The more long high speed driving you do, the less value the hybrid is going to have.
Never Politically Correct ~ I prefer the facts If you don't like what I say, get a life, or comment yourself.
I rented a Prius a few weeks ago for a trip. The total mileage for the trip was a little over 1300 miles (interstate highway) and I averaged a little over 45mpg for the entire trip. This is 88% of what the EPA says that I should. It would have gotten even better mileage if I had driven 55 the entire way instead of 75 (and the stormy weather didn't help). Given the age of the EPA tests, I would guess that they use 55 or 60 for the highway speed. I didn't do much city driving, but when I did, it was on strictly battery power for a large portion of it.
Driving style has a great impact on what you actually get for mileage. Since the hybrids have a screen showing instaneous and current trip mpg, the driver is more aware of how your behavior affects it. Stomp on the throttle to get on an uphill expressway onramp, and sure, it will show that it's only doing 9mpg. The real question is: what would the driver get with a 'normal car' under the same circumstances? Unless more of them start shipping with a little computer that displays the same instaneous and current trip mpg, its difficult to determine how much better the hybrids are performing compared to regular cars.
After driving a Prius for that weekend, I just wish I had $20K to spend on one. It got 50% better mileage than my regular car, had more room, and more trunkspace.
the good ground has been paved over by suicidal maniacs