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Can Cars Get 100+ MPG Today?

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Initial post: Jun 25, 2012 11:40:34 AM PDT
Last edited by the author on Jun 26, 2012 8:57:04 AM PDT
Vogelhn says:
Dear interested parties, because of personal reasons I must retract this posting. I'm sorry if this inconveniences anyone!

Posted on Jun 25, 2012 1:00:30 PM PDT
Gabe says:
You're absolutely correct and have solved the world's energy problems. Where teams of engineers, scientists, and billions of dollars of research have failed, you have succeeded.

On behalf of human civilization, I thank you.

Posted on Jun 25, 2012 1:42:34 PM PDT
Last edited by the author on Jun 25, 2012 1:44:39 PM PDT
Vogelhn says:
You're very kind!
I'm working on a concept to eliminate or at least improve this problem, but these things take time and I have yet to get the funding needed.
BTW, the original Wright Brothers designed and had built the first all aluminum gasoline engine to power their flight. Commercially available engines were unsuitable for their needs, they were too heavy and lacked the power. Their engine, however, was capable of efficiently getting ~2/3 of its fuel to burn near its max-timing power stroke to yield the power they needed. How remarkable, that they not only invented "powered flight" but also developed the early design principles of timely gasoline vapor combustion!

Posted on Jun 25, 2012 3:11:06 PM PDT
Carl G says:
While I may be completely wrong, I honestly don't think the federal or state governments want vehicles that can get 100 MPG because of the taxes they receive from every gallon sold. As of January 2012, the nationwide average tax on gasoline of 49.5 cents per gallon.


Posted on Jun 25, 2012 3:56:32 PM PDT
Davepl says:
I don't know where you got the idea that 2/3 of the fuel is wasted, but I'm fairly certain its untrue. Yes, otto cycle engines waste a lot of heat, but that's a completely different problem. Way back in the 19th Century the Atkinson cycle engine was invented to help this, and a variant of it is used in the Prius today.

Here's the problem in a nutshell: when the piston reaches the bottom of the bore there is still heat and expansion pressure left over in the cylinder. Atkinson cycle engines try to reduce this, turbochargers try to take advantage of it, turbine-extraction-direct-drive tries to make use of it, and so on. That's where you should be doing your reading.

In reply to an earlier post on Jun 25, 2012 4:01:57 PM PDT
JackV says:
And you may be completely correct.

Not sure about the 2/3 theory.

Posted on Jun 25, 2012 4:43:40 PM PDT
Last edited by the author on Jun 25, 2012 4:44:19 PM PDT
Nick says:
Anyone ever hear of some guy with a mid-2000's Honda Accord who achieved 60 mpg? But... here's the catch. He would push his car while in neutral for a half mile to get out of his neighborhood, then once he was in the car, he wouldn't run the air and he wore an ice vest to keep himself cool in the summer time. Then instead of hitting the brakes to come to a stop, he turned the engine off and coast to a stop, which is dangerous because then you lose control of the car since the steering wheel is basically locked and really can't be steered. So that's sacrificing important safety just for gas mileage.

I have a 2007 Mazda3 2.0 that averages 28 to 30 mpg with mostly highway driving at speeds ranging from 65 to 80 mph, an average of 70 to 75 mph. I rarely see less than 28.5, but did get 27 last week and just achieved 30 this week. That's fine for me. I don't need some goofy, expensive hybrid. The popular Toyota Prius... the HV battery (high voltage) costs around 5 grand. I've priced them out before at the Toyota dealer I work at. To me, that's not worth it compared to the price of gas. I spend about 30 to 35 bucks a week on gas, filling up weekly, so for a 4 week month, 120 bucks, give or take a few dollars. However, I won't need a $5,000 battery in the future, plus labor at nearly $100 per hour.

In reply to an earlier post on Jun 26, 2012 8:42:25 AM PDT
Last edited by the author on Jun 26, 2012 8:49:51 AM PDT
Vogelhn says:
Dave Plummer:
A turbocharger is ineffective in retrieving significant lost energy from IC-exhaust because its flowrate is too small for generating traction energy. Intermittent combustion gasflow doesn't fare well with turbines. IC-engines are low flow devices that can only use constant explosive/expansive air volume to produce sufficient locomotive power. IC turbochargers produce drops of energy compared to the available power in a gallon of gasoline. Only a jet engine's air turbine (Brayton Cycle) works well because of the HUGE (compared to IC engines) amount of airflow continuously expanding and running through it. The expansiveness of steam (Rankine Cycle) can also run turbines, but doesn't compete with Brayton.
Ponder this: A car travelling 60 MPH consumes about 2 GPH of gasoline and releases about 340,000 HPH (horsepower each hour) or 440 Watt-hours which is watts of released power each hour, that's huge (a typical home uses 1020 Watt-Hrs each hour). Doing the math, about 10% of a car's power is wasted heat, and 25% is used for 60 MPH locomotion plus drivetrain losses, so where does the rest go?

Posted on Jun 26, 2012 10:17:49 AM PDT
Last edited by the author on Jun 26, 2012 10:19:18 AM PDT
JackV says:
Only about 14%-26% of the energy from the fuel you put in your tank gets used to move your car down the road, depending on the drive cycle. The rest of the energy is lost to engine and driveline inefficiencies or used to power accessories. Therefore, the potential to improve fuel efficiency with advanced technologies is enormous.

combined hwy/city
Engine losses 70-72%, parasitic losses 5-6%, Power to wheels 17-21%, Drivetrain losses 5-6%, Idle losses 3%

This one takes the data and made this

Engine Losses - 62.4 percent

In gasoline-powered vehicles, over 62 percent of the fuel's energy is lost in the internal combustion engine (ICE). ICE engines are very inefficient at converting the fuel's chemical energy to mechanical energy, losing energy to engine friction, pumping air into and out of the engine, and wasted heat.

Advanced engine technologies such as variable valve timing and lift, turbocharging, direct fuel injection, and cylinder deactivation can be used to reduce these losses.

In addition, diesels are about 30-35 percent more efficient than gasoline engines, and new advances in diesel technologies and fuels are making these vehicles more attractive.

Idling Losses - 17.2 percent

In urban driving, significant energy is lost to idling at stop lights or in traffic. Technologies such as integrated starter/generator systems help reduce these losses by automatically turning the engine off when the vehicle comes to a stop and restarting it instantaneously when the accelerator is pressed.

Accessories - 2.2 percent

Air conditioning, power steering, windshield wipers, and other accessories use energy generated from the engine. Fuel economy improvements of up to 1 percent may be achievable with more efficient alternator systems and power steering pumps.

Driveline Losses - 5.6 percent

Energy is lost in the transmission and other parts of the driveline. Technologies, such as automated manual transmission and continuously variable transmission, are being developed to reduce these losses.

Aerodynamic Drag - 2.6 percent

A vehicle must expend energy to move air out of the way as it goes down the road�less energy at lower speeds and progressively more as speed increases. Drag is directly related to the vehicle's shape. Smoother vehicle shapes have already reduced drag significantly, but further reductions of 20-30 percent are possible.

Rolling Resistance - 4.2 percent

Rolling resistance is a measure of the force necessary to move the tire forward and is directly proportional to the weight of the load supported by the tire. A variety of new technologies can be used to reduce rolling resistance, including improved tire tread and shoulder designs and materials used in the tire belt and traction surfaces.

For passenger cars, a 5-7 percent reduction in rolling resistance increases fuel efficiency by 1 percent. However, these improvements must be balanced against traction, durabillity, and noise.

Overcoming Inertia; Braking Losses - 5.8 percent

To move forward, a vehicle's drivetrain must provide enough energy to overcome the vehicle's inertia, which is directly related to its weight. The less a vehicle weighs, the less energy it takes to move it. Weight can be reduced by using lightweight materials and lighter-weight technologies (e.g., automated manual transmissions weigh less than conventional automatics).

In addition, any time you use your brakes, energy initially used to overcome inertia is lost.


In reply to an earlier post on Jun 26, 2012 3:17:04 PM PDT
Carl G says:
Hey, Jack, I'm about ready to come up your way to escape the heat. Today the thermometer reached 107.6 degrees.

In reply to an earlier post on Jun 26, 2012 3:19:36 PM PDT
Carl G says:
I'm all for doing whatever I can to save on gas but I just can't see myself pushing anything - any distance - anywhere.

In reply to an earlier post on Jun 26, 2012 3:52:47 PM PDT
JackV says:
Bring your sweater. It's 55 today. And raining. I can't believe it.

Posted on Jun 28, 2012 1:09:46 PM PDT
anyone whom did come up with a viable invention to reduce fuel usage has been successful in doing so and also has taken an everlasting dirt nap while the inventions and all research has went to missing into conspiracy... sorry the truth sucks sometimes. deal with it, now eat your gmo's before they shear your wool. anyone who believes anything the .gov has to say is sadly too dependent on the system.

Posted on Jun 28, 2012 1:20:57 PM PDT
Carl G says:
In the words of the late great president Ronald Reagan, the most terrifying words in the English language are: 'I'm from the government and I'm here to help.

Posted on Jun 28, 2012 11:21:49 PM PDT
Scott Harder says:
Yes, Cars can get 100 miles per/gallon. AND that's a gallon of water!

In reply to an earlier post on Jun 29, 2012 1:26:07 PM PDT
Carl G says:
That I am anxious to see.

Posted on Jun 30, 2012 8:30:03 AM PDT
Tim G. says:
if anyone has netflix,there is a documentary on there called covers this very thoroughly,just rather boring.several civilians have developed 100+mpg cars including one the size of a hummer!and late in the documentary an ex-shell employee admits to have tested an engine design that allowed 1000mpg....but gas companies pay the engine companies to make bad engines so they both profit money!

In reply to an earlier post on Jun 30, 2012 8:55:12 AM PDT
SpiderWebb says:
TG> You're kidding, right? You don't really believe that crap do you?

In reply to an earlier post on Jun 30, 2012 9:17:05 AM PDT
SpiderWebb says:
JV> Fascinating data and discussion. You guys know I drive a flex fuel '03 Tahoe. It gets 15.7 mpg in the summer and 16.9 mpg in the winter. My neighbor has a '11 Hybrid Tahoe and she only gets about 3 mpg more than I do, and I've got 4WD. (Different rear end ratios.) I've checked her DIM.

Her vehicle costs about $5000 more than a comparable conventional Tahoe. For 3 additional MPG, I can buy an awful lot of gas.

Gotta go. Will crunch the numbers later.

In reply to an earlier post on Jun 30, 2012 9:38:20 AM PDT
Tim G. says:
the 100mpg easily,the 1000...not so much.

Posted on Jun 30, 2012 11:25:43 AM PDT
SPC Barry says:
There was a car back in the 60s that was built and was quite efficient. It was an electric car that had a gas generator. The batteries were charged and the car had the ability to use it's rotating energy to recharge the battery. I think they generator burned like a gallon or so of gas on the journey across the country. Big gas at the time apparantly payed big money to buy the patents from the inventor. Anyway this is what this hippie told me who had a nice gig of transporting us new army recruits to meps and back. Take it for what it's worth, I thought it interesting and just crazy enough to be true. My like 6th grade teacher used to talk about the tire companies buying a patent on a tire that didn't wear down at all while still having acceptable grip and whatnot. It's all hyperbole I guess but it's believable considering all the big wigs have got eachother's hands in eachother's pockets. You'll see mpg rise as gas becomes more expensive which will give people more incentive to buy more fuel efficient cars and etc. It's a big money scandal as everything is in the modern day but as long as you're around 30mpg you're not going to be breaking your back to drive for the next 15 years or so I would guess.
As far as the above posts on effiency and internal combustion engines a lot of that is due to the practicality of acheiving 100% efficiency with fossil fuels. It's not perfect to begin with. In order to achieve 100% effiency you would have to impliment a lot of technologies that would increase cost and weight of the vehicle as well as increase the amount of places where the engine can fail. The most efficient vehicles will use turbochargers and higher grade fuels to get a more complete burn of the fuel by feeding more oxygen to the combustion process, however car manufacturers are forced to add more fuel and bring the a/f ratios up to ~11.5 which is incredibly rich but will prevent a catastrauphic failure while reducing effiency. It's a never ending discussion.

Posted on Jun 30, 2012 11:56:51 AM PDT
Last edited by the author on Jun 30, 2012 11:58:07 AM PDT
Spirit says:
How can anyone explain away the geo metro? That car was in production in the early 90s I think.......and people got 35 to 40 mpg with them if not more. How the hell do you explain that technology not advancing? How can a car get 35, 40 or more mpg hwy in the 90s and here we are, over twenty years later (if the metro was in production in the early 90s, I'm too lazy to look up the information), and people are applauding 40 mpg hwy? The metro got that mileage without using a hybrid engine. Now we're led to believe that car manufacturers have to cut corners, implement new technology and jump through hoops to squeak out every mpg so 40 can be achieved. The metro did it easily many years ago. We should and we can get well over 40 mpg now.

Posted on Jun 30, 2012 12:20:47 PM PDT
SpiderWebb says:
JV> CG> Let's say my neighbor gets 19 mpg on her hybrid and I get 16 with my Tahoe to make it easy. At 125,000 miles, I will have used 7813 gallons while she will have used 6579 gallons. That's a 1234 gallons difference in her favor but I have $5000 in my pocket that she doesn't have because she spent it on her hybrid. At $3.50/gal, that $5000 will buy an additional 1428 gallons. 1428-1234 = 194 gallons in my favor. At 16 mpg, I could have driven an additional 3014 miles for the same amount as what she spent on her car.

The average life of a new car is 8 1/2 years and The average mileage at that point is about 125,000. The above example serves to demonstrate that you would have to keep your hybrid about 10 years before it saved you any money. See below.

150,000 miles or 10 years. Me; 9375 gallons Her;7895 gallons 9375-7895=1480 gal in her favor. My $5000 buys 1428 gallons of fuel. Now she is slightly ahead by 52 gallons at 10 years but close enough! That's only two tanks filled.

Bottom line; Don't buy a hybrid unless you want to make a statement or plan to drive it more than 10 years.

In reply to an earlier post on Jun 30, 2012 12:31:10 PM PDT
SpiderWebb says:
The Chevy Cruze gets 40 mpg for $20,180 MSRP. It's a much nicer and safer car than that POC Metro.

I could design a car that would get 50 easily but I doubt if there would be many buyers. I'd make the car half as wide and line up the passengers behind me. You can get there several ways. Mine exploits aerodynamics! Hey! If packing is good enough for motorcycles, then why not cars?

In reply to an earlier post on Jun 30, 2012 2:09:25 PM PDT
Grumbler says:
not to mention that if you take your example to its full conclusion, you would have invested that 5,000 dollars so over the course of your 10 years you would have made interest on that 5k so you actually come out even more ahead...
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Discussion in:  Automotive forum
Participants:  37
Total posts:  87
Initial post:  Jun 25, 2012
Latest post:  Oct 2, 2012

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