I'm in agreement with the mudslinger here on gasoline, but wish to add some info/opinion.
MPG is misleading with regard to efficiency. It is a distance rating only.
I have spent a serious amount of time and energy looking at this and have an opinion. Seriously.
When I was a youngster learning 'bout cars and
engines (good animation), it became clear to me that the current deal is
very inefficient. Less than 25% in fact. I set out, like you and probably and many others, thnking about how to make a better mousetrap. I fell into the idea (now flawed thinking) that the best way to go was to do something with the restrictive and cruddy flowing valve as we currently use it.
After much time and effort, I came to the conclusion that I was working in the wrong area.
We should be focused on fuel delivery while at the same time FULLY vaproize and combust ALL the fuel.
If we could simply deliver fuel to the combustion chamber in a better, and more fully combustible way, we could easily increase current engine efficiencies. In theory, since we are only currently utilizing 1/4 of the energy in a gallon fuel using todays technology, doubling or even tripling engine efficiency is clearly possible.
I say, continue to work the alternate fuels. We will certainly need them.
In the short run, we need to develop much more efficient ways to vaporize and deliver "octane" to what is in place already.
Below is a little diddy, I wrote some years back when I was in research mode. More on the awareness side of things. It is my opinion that most people think 40 MPG is great, when in reality, it is no more efficient than a 10 MPG land yacht from the fuel utilization point of view.
Sorry for the long post here. I ramble sometimes.
The MPG Myth
Do you eat 1/4 of the food on your plate and throw the rest away?
Your car does. Every time it eats. Please read on.
Miles Per Gallon or MPG is a rating used to indicate how far a given vehicle can travel on a single gallon of gasoline. However, this does NOT indicate how efficient the machine actually is. The manufacturers taunt their most “efficient” vehicles using MPG numbers and this is not truly correct. This misleading term is constantly used as a rating of efficiency and I want you to think about MPG as it really is. A measure of distance traveled. That’s it. Nothing more. Remember that MPG as a rating, only indicates distance traveled and does NOT indicate how well the gallon of gasoline was utilized and its relation to the efficient use of the fuel.
This is a very important point. As you will see, actual fuel utilization numbers are virtually the same across the board for the typical gasoline powered vehicles of today.
Fact is, the typical 4 stroke, Otto Cycle type engine that is in the vast majority of vehicles today is less than 25% efficient! You fill your tank while your engine, at best, can only convert 1/4 of that tank into useable energy. The rest of the fuel, 3/4 of your tank, is simply wasted!
MPG is NOT an indicator of vehicle efficiency. MPG IS an indicator of distance traveled.
Let me give you a simple example.
Car A weighs 1000 lbs and gets 40 MPG
Car B weighs 4000 lbs and gets 10 MPG
Car A has a much better MPG rating but overall efficiency is EXACTLY the same as Car B. They both did the same amount of work.
Remember, I am not talking about the additional energy losses from the transmission, final drive gears, tires, aerodynamics etc. Those things go into computing a vehicles overall efficiency and can have a large effect on MPG, but here, I’m only referring to your engines ability to utilize a single gallon of fuel. The MPG number is based on how well the vehicle can utilize that original 25% useable energy.
While there are some minor variations between engine manufactures, current engine efficiency breaks down something like this.
Less than 25% is useable energy. This is the energy that the vehicle uses to power itself of which distance traveled is equated.
+/- 33% is wasted heat energy that goes out the tailpipe.
+/- 33% is wasted heat energy that is removed by the cooling system and dumped out the radiator.
+/- 7% Energy is lost from reciprocating engine parts.
+/- 2% Energy is lost to friction.
Note that there is so much extra energy released by the fuel, that the engine would destroy itself quickly by overheating unless a cooling system is in place to remove it.
While there are still minor gains to be made in materials, thermal barriers and maybe variable cam timing among other “tricks” we’re mostly done here. Those wily engineers can’t stuff any more valves in ‘em. We’ve got good ignition control nowadays (no more points for those old timers out there), and lubrication is also very good. There is comparatively little more to be gained in these areas. It is true that if you could invent a good flowing replacement for the current valve design, you would be an instant billionaire. Good luck though. I’ve spent a good deal of time on that and I can say in all certainty that it is a tough nut to crack.
In my opinion, there is still a ton of room to gain efficiency in the delivery, atomization and vaporization of current fuel. The Hot Vapor Cycle idea put forth by the late Henry “Smokey” Yunick makes sense, yet sadly, for whatever the reason, concepts like this are not pursued.
It is important that you understand that just because a vehicle manufacturer claims a car to be efficient because it gets 40 MPG, that information is somewhat misleading and only a small part of the story. It is not a true indicator of efficiency. Efficiency should be referenced as to how well the FUEL gets utilized and NOT how far a vehicle can go. Like all other efficiency ratings, it should be stated as a percentage that the general public is aware of. Try this sometime. Ask someone “How efficient is your car?” The typical reply is “I get xx miles per gallon”. The populace is under the misguided thinking that MPG = Efficiency.
I’d like to see a vehicle overall efficiency rating, listed as a percentage, on a new car sticker as well as the MPG rating. That would be a whole new sense of sticker shock! An example of a typical sticker of today might read: 25 MPG City / 35 MPG Highway / 23.8% Efficient.
You now have the basic understanding and knowledge that your car in reality is an energy inefficient contraption that is less than 25% efficient! For ANY manufacturer to call their vehicle “efficient” is pathetic and misleading….unless you consider 25% efficient.
Note here that Hybrids like the Prius are still only about 35% efficient.
Research these facts for yourself and confirm that I am not a lunatic and then whenever possible make others aware as well. Public awareness is a powerful thing. That alone can create innovation and spur change for the better.
Vast amounts of energy can be saved and a better environment can be ours if we humans make serious efforts to better the technology for our ground transportation needs.
Thank you.
Fun search words:
Four Cycle Engine
Nicolaus August Otto
Henry “Smokey” Yunick
Hot Vapor Cycle