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."
Personally, I'm interested in hybrids but not for fuel efficiency reasons. I'd like to see auto makers combine the output from different energy sources into all-wheel acceleration of a normal car. I remember seeing something on the news a few years ago about Ford experimenting with that on an Explorer, trying to jazz up the acceleration of a bigger vehicle. I don't know what became of that testing, if anything. But it would be extremely cool to see that technology in a small, sporty car.
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....
An interesting alternative fuel is biodiesel:
- We can make it in the US
- Runs in existing diesel engines
- Almost all emissions reduced vs. dinodiesel
(for NOx there are some interesting additives
being produced).
- Much less toxic/dangerous than dinodiesel/gasoline
- Exhaust smells like french fries!
I never got below 50MPG, ever, and that was living in the thin air of Flagstaff, AZ, at over a mile in elevation. I got closer to 60MPG in the lower and warmer Phoenix, AZ.
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.
That bring a smile to my face first thing in the morning. I can't wait for my "HYBRID1" plates to arrive for my 63 Pontiac with a 400 and dual Edelbrock carbs :)
(B) + (D) + (B) + (D) = (K) + (&)
In reality the best price/pollution ratio today is a small turbodiesel. The best example is the Volkswagon Jetta TDI, the Jetta gets real world numbers within 20% of the hybrid's claims (probably higher than the real world performance of the Civic Hybrid for example). Modern turbo diesel engines have eliminated most of the historic problems of diesel engines (soot mostly) but they still have problems with NOX emissions.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
The Honda Civic Hybrid is an example of a hybrid is set up with the following:
Energy is lost in the conversion from gas to electricity, it's also lost in the storage in the batteries and the usage from the batteries to the wheels. You konw and I know that while normally this would all be lost in the braking, now it is stored and used to assist with acceleration.
The odd part is that while driving where you aren't using the brakes a lot, the transmission, weight improvements and aerodynamics will be the only improvements in your efficiency. The electrical assist means that your engine can be improbably weak, but I don't know if that necessarily translates to a more efficient engine.
Here's something which nicely describes why I'm skeptical about the true performance of hybrids:
1992 Civic line:_ Civic.shtml
http://www.fueleconomy.gov/feg/bymodel/1992_Honda
2004 Civic line (including hybrids)_ Civic.shtml
http://www.fueleconomy.gov/feg/bymodel/2004_Honda
I'm not sure why, but it looks like my 1992 1.5L Civic Hatchback is(was) more fuel efficient (city and highway) than the modern 2004 Civic Hybrid. I don't think U.S. government numbers are right, but they're close enough to try to make some kind of a point :-)
As an aside, I was looking into the hybrid transmissions and from what I could tell... I was wrong, the Honda Insight was manual-only, but the newer hybrids sometimes sell with the choice of an automatic or continuously variable transmission... oddly, the fancy transmission hurts highway fuel efficiency, but it helps in the city.
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)
A 2004 Honda Civic Hybrid to a 2004 Honda Civic would be a more reasonable comparison than my 1992 to a 2004... the 2004's have bigger engines and are less fuel efficient. I'd also expect the 2004 hybrid to have more horsepower than my 1992 car... so I'll admit, it's not a fair comparison...
But there may be less expensive, more fuel efficient non-hybrid vehicles on the market.
(In reality, I get about 37MPG on the highway, ~30 in the city... the car _is_ 13 years old)
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!
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
Honda has a new Diesel powered car that isn't a hybrid, and is getting 76 MPG (U.S. gallons) in real-world testing by the FIA. It's also breaking speed records for its class in the FIA testing (with the exact same cars used for the fuel efficiency test). I'm curious as to why diesel powered cars aren't more popular in the US, they can be much more efficient, and with recent advances in catalytic converters, and technology, these new diesel engines run very clean and very quietly.
There's no batteries to worry about, and you get a fullsize (well... not subcompact like most hybrids anyway, hehe) car with a full trunk to use.
-Jesse
Nothing says "unprofessional job" like wrinkles in your duct tape.
I can't speak for the Honda, as I have the Toyota Prius, but I get consistently 48-9 city MPG, (the '02 P is rated at 47 city).
If you don't know how to drive a hybrid, then you will get poor MPG. Period. Here's how to get high MPG in a hybrid:
It is absolutely understandable why people try to drive the way they are taught: smooth acceleration, hit the brakes often, etc., but that is the antithesis of getting good gas mileage in a hybrid.
Finally, the main goal of the hybrid is reduced emissions; increased MPG is a byproduct.
Yeah, right.
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.
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!
Biodiesal is a good fuel for replacing some of our oil usage. The other main benifit that you forgot to mention is that it is carbon neutral since any CO2 put into the air from exhaust is balenced by the CO2 taken out of the air by the plants grown to create the biodiesel.
At the moment it is only twice as expensive as diesel here in the US (although what will all the agricultural tarriffs jacking prices up and subsidies bringing them down, it is damn near impossible to calculate the true economic cost of biodiesal). There is the kink that all of our fertilizers are fossil fuel based, so the cost of producing biodiesal will go up as the cost of fossil fuel goes up. The only other alternative is to go to crop cycling and other natural sustainable methods of fertalization, which are also less cost efficient.
However the real killer is that if you sit down and do the back of the envelope calculations, you will find that growing enough biofuel to replace all the world's oil usage would require all the arable land on the entire planet. In other words we would have to bulldoze all the woods, rainforests, plains, and marshes, and replace them with biomass crops. Not only will will destroy most of the natural habitats on the planet, but at this point we also loose the carbon neutral benifit because we are taking other plants out of the carbon cycle to put ours in.
So Biodiesal, like solar, is a good supplement to our enegry needs, but not a sustainable complete replacement.
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!
The Toyota Prius uses an ICE system. It involves two electric motors, can operate "silently" (purely off the electric motor) at low speed, and can only be used in conjunction with an automatic transmission.
The Honda hybrids use a system called "IMA", that functions more like an electric turbocharger. If a Honda hybrid is moving, the gasoline engine is running. Well, OK, there is an exception to this if you're coasting to a stop at speeds below about 10 MPH (3 MPH in the CVT), with the brake pedal depressed, the engine goes into "auto idle stop" mode. The Honda design can be used with a manual transmission (leading to the extraordinary mileage of certain models) and is less complicated than the Toyota system, but otherwise seems to be a wash as far as advantages when comparing the two.
I have to admit some bias here: I think the Honda Insight is in a class by itself. It was a brand-new model introduced in Japan in 1999, engineered from the ground up to be the MPG king of the mass-produced world. It sacrifices a lot to be that: no rear seat, "unusual" design (my brother-in-law says "ugly", but I think it gives the car "character"), all-aluminum construction (painful, painful body repair bills), high insurance costs (on par with high-end rear-wheel-drive sports cars), a fairly stiff econo-box-like ride due to really hard little wheels, a crappy stereo (until 2004, when they put a much nicer model in), and hardly any selection of "options": if you have an Insight of a particular year, other than air conditioning and transmission type, your choices are extremely limited.
But I still love the car :) Now, back to responding to your post!
The engineer that talked about the Prius "running off batteries and not using gas" must have been off his rocker, if what you describe is correct. The energy has to come from somewhere, and in the case of these hybrids, that's from the gas tank. The gasoline motor must run to recharge those battery cells. And the chemical energy (gas tank) to kinetic energy (motor) to chemical energy (battery) transition wastes a good deal of that energy. Add to that kinetic energy to potential energy losses due to regenerative braking, actual brake pads being used in hard stops, and it's a recipe for poor efficiency.
The numbers back this up: in city driving, a hybrid frequently turns in extremely disappointing MPG numbers due to these inefficiencies. The Prius takes a hit in its highway MPG numbers, because it has to leech power off the gas engine to recharge the battery it depleted in city driving. The Honda cars take the hit from the gas motor occasionally idling (rather than going into auto-idle-stop), and acceleration from a stop draining nearly as much gas as a "normal" car.
That said, a hybrid will beat the pants off any similarly-driven traditional gasoline-powered vehicle for efficiency in those conditions. But when the EPA rates city mileage higher than highway mileage, it's not taking into account losses in the battery pack: the car ends the test with a battery pack lower than it started.
Sadly, you can't beat the laws of thermodynamics:
- You can't create or destroy energy
- You can't hope to ever do better than break even
- You can only break even at absolute zero
Sounds like my life sometimes...Matthew P. Barnson
I learn what I think when I read what I write
Naturally, the technology, not the drivers, that is responsible for the poor fuel economy.
Nonsense. When I drive my 2003 Honda Civic Hybrid (yes, I actually own one, potentially unlike many other people posting here) on the highway, I am careful on the gas (I take a speed hit going up hills, I utilize descents, et cetera). On the Pittsburgh, PA - Washington, DC drive, I consistently average 51 MPG for the length of I76, I70, and I270. On the George Washington Memorial Highway along the Potomac, I can keep it above 53 going in and out of the city. For local traffic, I accelerate slowly and brake slowly (when possible) and that helps keep it above 48 MPG.
On the otherhand, when I feel like having some fun, the gas miliage can drop down into the low 40s (42-46 MPG). For my Civic, that is terrible, but still better than 90% of the cars on the road. I consistently score 575+ miles out of my 12.7 gallon tank.
A terrible driver could take an NSX and lose every race. An excellent driver can take a Kia and kick some serious ass. Likewise with fuel economy, a bad driver can make the most efficient vehicle guzzle gas while a good driver could get some decent range out of an SUV. The point is, a car's technology is only as good as the driver.
I think a lot of people out there get a gasoline-electric hybrid vehicle and assume that they don't have to think. That's not the case. There's a very good reason why the Prius and the Civic Hybrid show you whether the motor is assisting or charging and show you your instantaneous fuel economy. These tools help the driver alter their habits to get the best performance. If people are dumb enough to spend the money on one of these vehicles and then not use the technology correctly (understand how to drive with maximum efficienty and change their habits), it's not the fault of the engineering, it's the fault of the consumer.
Join Tor today!
It sounds like the article wants to appease the conscience of SUV owners, whom as we all know drive considerately and maximize fuel economy.
Don't use air conditioning, ever. (2 to 4 mpg)
Drive at a steady speed, about 40 mph, in top gear.
Choose a route that doesn't involve hills.
Don't use oxygenated gasoline. (as if you have a choice!) (15% efficiency loss)
Don't drive through snow. (It takes energy to push the snow aside.)
Don't drive in very cold weather. (Cold makes rubber stiff, so tires absorb more power.)
If you can, adjust the spark timing for maximum efficiency. This setting may disagree with manufacturer's recommendations.
Contribute to civilization: ari.aynrand.org/donate
I have owned my 2004 Prius for about six months. During a typical week, where most of my driving consists of the commute to and from work, my gas mileage ranges from 46 to 49 mpg. I live in San Diego, California and the drive has a lot of up and down stretches which may tend to keep the numbers down. My best mileage is on the freeway during the rush hour commute. With speeds down around 15 mph, the car spends a significant part of the drive running on battery only. Unfortunately (or fortunately) my work schedule has me doing most of my commuting during non-rush hour times. During one week however, when I did have a 9 - 5 work schedule, I averaged 52 mpg as reported by the dashboard MPG readout. My wife and I have made one 840 mile round trip to Nevada since we have owned the car. We averaged 49 mpg on the trip with speeds in the 65 - 75 mph range. When I bought the car, I didn't expect to get the EPA mileage. Considering that I haven't changed many of my driving habits since I got the Prius, I am very happy with the mileage that I am getting.
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