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350 MPG cars

Ranb

Penultimate Amazing
Ranb
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http://www.cnn.com/2005/TECH/08/15/hybrid.tinkerers.ap/index.html

From the article, the man who put extra batteries in his Toyota to allow him to run 50% on the gasoline engine and the rest of the power on the batteries, claims he gets 250 miles to the gallon. Sounds not too bad until he goes on to say that he can charge his battery pack from a home outlet for 25 cents. How far does a quarter's worth of eletricity go in San Francisco. I don't think a standard car battery can be fully charged at that low a price.

Is this just another example of a reporter believing everything they hear?

Ranb
 
Do the math....

Lets do some math: A large car battery may have 700 amp hours at 12 volts. 700 times 12 equals 8400, or 8.4 kilowatt hours. My southern California juice cost 17 cents per, so $1.42. YMMV.

BUT, on hybrid cars: Your gain over a gas car is in the re-generation of energy that would normally be wasted in braking. The current hybrids hardly gain enough to offset the energy used to haul around the batteries. A little Geo Metro gets better milage than a Prius. Plus, what about the 'pollution units' used in adding batteries, a 200 pound motor, and equivalent generator to an auto that already has the regular drive system ? Hybrid seems to me to be a 'feel good' concept rather than an energy saving idea.
 
Re: Do the math....

casebro said:
The current hybrids hardly gain enough to offset the energy used to haul around the batteries. A little Geo Metro gets better milage than a Prius.
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"Hardly gain enought to offset the energy"? No. If I drive at whatever speed I want on the expressway, I get 65 mpg in my Insight. If I watch my speed, I can push that up to high 70's. In the city, I am getting 32-42 mpg.
 
A few months ago, they had a Science Friday segment on this. A university-sponsored group was modifying the Honda Prius to allow home-recharging.
This was the sort of figure given as to actual MPG when one uses the home-charged batteries for most driving, the gasoline engine only kicking in for longer trips.

There was not much mention of the pollution caused by the generation of the electricity, which is of course highly variable.

The interesting thing to me was that both Honda and Toyota, as part of their marketing campaign here in the states, were promoting the fact that you do NOT have to "plug in". You just get in and drive. Evidently, for the American market, the ability to plug-in was considered a poor selling point.
However, such vehicles sold in Europe do come equipped with the plug-in feature, and is widely seen as a desireable feature. Of course, several countries in Europe have considerable infrastructure that allows recharging even when you park.
 
casebro wrote:
Hybrid seems to me to be a 'feel good' concept rather than an energy saving idea.
Click to expand...

I think perhaps not. My neighbor gets about 50 mpg with his prius under a variety of driving conditions. I get about 30 mpg with my Prelude or my Accord for freeway driving and around 25 mpg for in town driving. His Prius has more passenger room than my Accord.

Of course there are maintenance cost and initial cost issues that are important as to figuring out whether he is actually saving money with his Prius, but if saving gas is the issue hybrids work.

Hybrids not only save gas with regenerative braking, they save gas by not running the engines when the car is stopped, by using the electric motor for getting the car moving thereby eliminating clutch slip losses and perhaps by running the gas engine in a narrower RPM band thus allowing the engine to spend more time in its most efficient mode.

edited to correct statement about getting the car moving
 
Bikewer said:
A few months ago, they had a Science Friday segment on this. A university-sponsored group was modifying the Honda Prius to allow home-recharging.
This was the sort of figure given as to actual MPG when one uses the home-charged batteries for most driving, the gasoline engine only kicking in for longer trips.

There was not much mention of the pollution caused by the generation of the electricity, which is of course highly variable.

The interesting thing to me was that both Honda and Toyota, as part of their marketing campaign here in the states, were promoting the fact that you do NOT have to "plug in". You just get in and drive. Evidently, for the American market, the ability to plug-in was considered a poor selling point.
However, such vehicles sold in Europe do come equipped with the plug-in feature, and is widely seen as a desireable feature. Of course, several countries in Europe have considerable infrastructure that allows recharging even when you park.
Click to expand...
Toyota Prius, Honda Insight. We have just taken delivery of Toyota Priuses at work - I don't think they can be plugged in. I remember reading somewhere that the Prius was optimised for low emissions rather than fuel economy, does anyone know whether this is true or not?
As davefoc says above the Prius has more tricks up its sleeve than regenerative braking. Most noticeable is the petrol engine turning off whenever you stop in traffic - quite disconcerting at first.
 
My wife has a 1986 Honda Civic which got 55 mph when it was new. She always laughs when people talk about the "great" mileage of the hybrids.

CBL
 
CBL4,
It is true that it is possible to reduce the size of a car and get better gas milage. There are cars that can get over 1400 mpg.
http://www.doe.state.in.us/octe/technologyed/pdf/SuperMile-info.pdf

The trick is to get better mileage while not reducing the comfort, safety, speed and overall functionality of the car. Hybrids seem to accomplish this.

Although, if I was looking for a high mileage commuter type car right now I think I would get something like your wife drives. I like small cars and I think I'll let other people experiment with the hybrid technology for awhile.
 
Once again, we have skeptics on both sides of the issue. We need to compare a normal car to the same car with a hybrid system, in order to see how many mpg it truly saves. Even the current Civic cannot be compared to a Civic Hybrid, since the Civic Hybrid has a smaller engine than its normal cousin. (1.3L Hybrid compared to a baseline 1.7L for the normal Civic)

Anyone got any hard data?
 
The trick is to get better mileage while not reducing the comfort, safety, speed and overall functionality of the car. Hybrids seem to accomplish this
Click to expand...
Clearly my wife's car is not as nice a car as a Prius. However, if mileage is the goal, much of the advances can be accomplished with old, reliable and cheap technology. Her 19 year old Honda still drives fairly well. In addition, it was one of the cheapest cars you could buy at the time.

If people would just buy cars with manual transmissions and keep their tires inflated properly, they could increase their mileage by 10 - 20%.

Pushing for manual transmissions and fully inflated tires seems a lot more sensible than hybrids.

CBL
 
Keneke said:
Once again, we have skeptics on both sides of the issue. We need to compare a normal car to the same car with a hybrid system, in order to see how many mpg it truly saves. Even the current Civic cannot be compared to a Civic Hybrid, since the Civic Hybrid has a smaller engine than its normal cousin. (1.3L Hybrid compared to a baseline 1.7L for the normal Civic)

Anyone got any hard data?
Click to expand...

Tough to do. The Prius is soo slippery that one would need to take a Prius apart, gut the electrics, add a conventional starter, and then drive it. Otherwise, you would be comparing Pippins to Grany Smith's. But I do think it would prove that there is very little, if any, advantage to Hybrids.

My bro-in-law just bought a used Prius. He figures that at $2.50/gal, it won't pay for itself in gas savings. Then add the adittional 'pollution units' for building an extra 300 pounds of batteries and motors, and it's another piece of poor judgment / political statement by a genius. What do you do with old Li-Mh batteries? Lead-acid batteries are 100 percnt recyclable.....
 
It's long been known how to make a car that gets good mileage:

Make it light -- this can be done by making it small or by using exotic materials -- or preferably, both.
Make it low drag Very small, or very streamlined, or preferably, both.
Reduce the rolling resistance. Large diameter, hard wheels.
Get a good impedance match between the motive power and the road.
You can use multiple gear transmissions, or infinitely variable transmissions, or a battery with an electric motor and a solid state controller to match the source to the load.
Design the engine to run near its torque peak all the time. Shut off the engine instead of idling it.

I think the hybrid's advantage mostly lies in being able to design the engine to the average load rather than the peak load. I don't think you'll see a high mileage hybrid towing a boat up into the mountains, replacing the V8 pickup. But it lets you use a smaller, lighter engine, allowing a smaller, lighter car. And that can be a good design compromise for some applications.

Dynamic braking (using the motor as a generator when slowing) can probably help 9 or 10 percent theoretically, but does much, much worse in practice, because drivers don't like the "feel'.
Compare the heat radiating surface of your brakes to the heat radiating surface of the engines radiator . The heat from the brakes is the energy dynamic braking proposes to recover -- and it can't get all of that.

With respect to the OP, calculating the miles per gallon of an car that can be plugged in is sort of an execrcise in futility.
What if the driving cycle is so short the IC engine is not required? You could, in that case, get infinite miles per gallon!

And as a general solution, does it scale? Right now, electricity is pretty cheap. There's no "road taxes" on it, because so few people use it to drive. If a significant portion of the population starts using electricity to drive, there _will_ be taxes on it, reducing any current (Heh!) advantage. The price of electricity will probably go up due to increased demand, too.
 
CBL4 said:

If people would just buy cars with manual transmissions and keep their tires inflated properly, they could increase their mileage by 10 - 20%.
Click to expand...


And if they avoided jackrabbit starts and speeding, they could increase their mileage even more.

CBL4 said:
Pushing for manual transmissions and fully inflated tires seems a lot more sensible than hybrids.

CBL
Click to expand...

They are not mutually exclusive - we can do both.
 
I love these types of threads.

Now..can anyone tell me if they have purchased one of those acclaimed Tornado vortex devices that go in by the air cleaner or the intake duct in front of the carb intake, to increase gas mileage and horsepower? These devices are not applicable to my 2 vehicles, unfortuantely. And I'm dying to know the truth regarding these things.

Oh. Something else. 6-ply tires can be aired up to 50 or more psi compared to the standard 4-ply 28-32 psi. Why don't we all have 6-ply tires then, to reduce rolling resistance?
 
Originally posted by TjW
Right now, electricity is pretty cheap
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For the foreseeable future, there will be a great electricity surplus during the night. If the price of electricity varied during the day, overnight charging could be made very cheap. If the car needed to be charged during the day, it would be a different story.

Originally posted by Ladewig
They are not mutually exclusive - we can do both.
Click to expand...
Yes but hybrids are expensive with possible battery disposal problems and the technology has not been shown to be robust. Manual transmissions and properly inflated tires save money and are more reliable in addition to saving fuel.

CBL
 
Hard, tough tires may give excellent rolling resistance, but really ratty ride and traction. Everything is a trade-off.

I had a Datsun truck once, 1970 or so. Thing had 6-ply tires and rode like a .....
 
....truck?

But with gas at @2.699 a gallon today, I'll take my lumps!
 
Iamme said:
I love these types of threads.

Now..can anyone tell me if they have purchased one of those acclaimed Tornado vortex devices that go in by the air cleaner or the intake duct in front of the carb intake, to increase gas mileage and horsepower? These devices are not applicable to my 2 vehicles, unfortuantely. And I'm dying to know the truth regarding these things.
Click to expand...
It's a pity that we've never had a thread on this before, isn't it?
 
CBL4 said:
My wife has a 1986 Honda Civic which got 55 mph when it was new. She always laughs when people talk about the "great" mileage of the hybrids.

CBL
Click to expand...
They've since raised the speed limits, in most states it's now 65 or 70 mph, doesn't she get scared w/ all that traffic whizzing by her? I imagine merging is also a problem... ;)
 
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