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200 MPG on fumes
legear
Member Posts: 6,716
What do our resident experts think about this?
Functional for every day use?
Gas saver dodge running on fumes:
http://youtu.be/ZFxwJ8mIDtA
Functional for every day use?
Gas saver dodge running on fumes:
http://youtu.be/ZFxwJ8mIDtA
Comments
Allen
BOOM
The first thing we need to understand is that a gasoline engine in order to function properly needs to be fed both fuel and air in the proper ratio. In modern vehicles this ratio is achieved by electronic measurement of air, fuel, and temperature. This allows for a very controlled burn in the cylinder.
The second thing we need to understand is that gasoline is being atomized before entering the cylinder, or as it enters the cylinder depending upon the delivery system. In old vehicles we have a carburetor. Air being drawn into the cylinder is directed through a venturi. The low pressure and increased speed of the air cause fuel to be forced through a jet into the intake airstream where liquid fuel is vaporized and mixed with the air. Jetting determines the proper air/fuel ratio.
Newer vehicles address fueling somewhat differently in that the fuel is electronically injected into the airstream and the mixture is controlled via the ECU. So single port, multi-port, or direct injection. In all cases a computer controls the air/fuel ratio.
Now to the engine itself... Gasoline engines will run outside the optimum air/fuel ratio. Too rich and unburned fuel will be a part of the exhaust component. Power will be greatly compromised and the engine will not perform well. Leaning will first result in slightly increased performance but cylinder temps will quickly go into the danger zone. Past a point the engine will not have enough fuel to continue to operate with a resulting stall.
Now to the claim set out in the OP... A gasoline engine returns less than 30% efficiency in the real world. In other words about 2/3 of the fuel used is wasted. The waste being in heat, internal friction, and a multitude of other factors. No matter what we do it takes a certain amount of energy just to keep the mill turning over.
Further, it takes a certain amount of energy (calories) to do a specific job. This is the reason that while alcohol burns cleaner than gasoline, it takes roughly twice as much to do the same amount of work as alcohol contains about half the calories per unit compared to gasoline.
Claims of unbelievable fuel economy are just that... Unbelievable! Certainly it's possible to lean a motor at idle to a point where it will still run thereby using less fuel than normal. But there must be enough energy to keep that engine running. And should that engine be required to do any real work it will need the fuel energy required for the task. This aside from the fact that an aggressively lean condition will result in engine damage.
Given that the internal combustion engine is inefficient by its very nature and given that even at idle there exists a certain level of energy required to keep things turning, the claims made are ridiculous.
Don't all gas engines run on fumes?
Allen
Yep.
Also, excellent post nord.
200 Mpg in 1978
while concept may be viable, the way he has it set up there is no way to increase the throttle and that's putting it simple
edit: 55mph on idle ?, I don't think so
There are certain unbreakable laws of physics. One of them being that under a given set of conditions it takes a set amount of energy to accomplish a given task.
For the sake of simplicity let's just assign some numbers to a task. Let's say that we wish to move a 4000# object over the distance of a mile on absolutely flat terrain. We calculate all the factors involved and determine that the job will require 10k calories.
So...
Fuel type is unimportant. All we need to know is that 10k calories will be needed.
Method of extracting 10k calories worth of work is important. In our traditional internal combustion engines about 2/3 of the energy consumed is wasted in heat and mechanical losses. This figure is basically non-negotiable within but a few percentage points.
The result being that in order to obtain 10k calories of work it actually requires 30k input calories to do the job.
Think for a moment about the claims and do some simple math. It really does take a set amount of energy to do a particular job. In this case a 4000 pound vehicle being moved over a set distance on a particular course at certain speeds in certain weather conditions and altitudes. The caloric requirements can be calculated.
Next it might be of some profit to determine the number of calories (energy content) in the gallon of gasoline we're using. Just go out on the Internet and the figures are readily available.
Let's just say that the entire task to be performed will require 3k calories. (A ridiculously low number but one that is easy to understand.) We'll further stipulate that a gallon of gasoline contains 3k calories of potential energy. (Again not a real number.)
But the problem here is that our energy conversion to do this job is only about 1/3 efficient. Thus it will take about 9k calories to obtain 3k calories of work.
So do the math. Does the energy content of the fuel being used meet or exceed that required to perform this job? Does the fuel contain the added calories needed to account for the inefficiency of our engine? If so, then 100 miles on a gallon of fuel is possible. If not, then all the powers of heaven and earth won't make the grade.
Now the claim of 100 mpg for a 4000 lb. car? Do the math. No matter how you cut it a gallon of gasoline does not contain the required energy to do the job.
And thus claims and facts depart company into the realm of fantasy and outright lies. Sorry, but what I've shared is the absolute truth.
The engine would then not need to be throttled back so much and less work would go into drawing intake air past a nearly closed throttle.
It would of course be a very small gain, nowhere near 200 mpg.
But as said, given the modern car's weight, drag, and friction (both internal and in the airstream, and against the roadway), it is going to take a certain amount of power to move the car at a given velocity. The efficiency of all parts can be increased, but ultimately you hit a brick wall, beyond which the efficiency of the engine cannot be substantially increased anymore. Right now that figure stands around 30%. To get past that wall, finding a way to reclaim some of the energy lost as heat would be needed. This is certainly possible; however, any device doing this will add weight in and of itself, further harming efficiency.
I won't say we can't improve the gas engine at all. But for a vehicle of a given size, we are coming very close to the maximum amount of energy we can gain from a given amount of fuel. Barring some breakthrough in heat waste reclamation, mechanical friction reduction, etc., we're only going to be able to eke out a few more percentage points on the system I'd say.
I'd really like to see more natural gas vehicles. It's less energy dense and would be less fuel efficient than gasoline, but as it is more abundant than oil, requires less refining, burns cleaner, and can run in most gasoline engines with minimal modifications, it would be a fine (and cheaper, more available) alternative. It has about 84% the power at standard pressurization as does gasoline, meaning you'd see about 16% less fuel efficiency; but at a far cheaper price that's quite acceptable.
Conspiracy kooks point to his legal troubles and death at age 26 to "prove" his invention must have been real, and he was silenced by sinister powers.
Here we go again. Gasoline or any fuel contains a certain number of calories per measure. Since we're talking a gasoline engine here I'll limit my comments to this type of engine:
The first thing we need to understand is that a gasoline engine in order to function properly needs to be fed both fuel and air in the proper ratio. In modern vehicles this ratio is achieved by electronic measurement of air, fuel, and temperature. This allows for a very controlled burn in the cylinder.
The second thing we need to understand is that gasoline is being atomized before entering the cylinder, or as it enters the cylinder depending upon the delivery system. In old vehicles we have a carburetor. Air being drawn into the cylinder is directed through a venturi. The low pressure and increased speed of the air cause fuel to be forced through a jet into the intake airstream where liquid fuel is vaporized and mixed with the air. Jetting determines the proper air/fuel ratio.
Newer vehicles address fueling somewhat differently in that the fuel is electronically injected into the airstream and the mixture is controlled via the ECU. So single port, multi-port, or direct injection. In all cases a computer controls the air/fuel ratio.
Now to the engine itself... Gasoline engines will run outside the optimum air/fuel ratio. Too rich and unburned fuel will be a part of the exhaust component. Power will be greatly compromised and the engine will not perform well. Leaning will first result in slightly increased performance but cylinder temps will quickly go into the danger zone. Past a point the engine will not have enough fuel to continue to operate with a resulting stall.
Now to the claim set out in the OP... A gasoline engine returns less than 30% efficiency in the real world. In other words about 2/3 of the fuel used is wasted. The waste being in heat, internal friction, and a multitude of other factors. No matter what we do it takes a certain amount of energy just to keep the mill turning over.
Further, it takes a certain amount of energy (calories) to do a specific job. This is the reason that while alcohol burns cleaner than gasoline, it takes roughly twice as much to do the same amount of work as alcohol contains about half the calories per unit compared to gasoline.
Claims of unbelievable fuel economy are just that... Unbelievable! Certainly it's possible to lean a motor at idle to a point where it will still run thereby using less fuel than normal. But there must be enough energy to keep that engine running. And should that engine be required to do any real work it will need the fuel energy required for the task. This aside from the fact that an aggressively lean condition will result in engine damage.
Given that the internal combustion engine is inefficient by its very nature and given that even at idle there exists a certain level of energy required to keep things turning, the claims made are ridiculous.
You can detect the "pinging" as that motor is running -- that is the fuel/air mixture detonating. Production motors are designed to utilize fuel by burning it and causing the (relatively) slow expansion of gasses in the cylinder.
Detonating a fuel/air mixture (in a properly tuned motor) is utilizing the kinetic energy of the gas molecules directly impinging against the piston. This detonation -- and subsequent kinetic (from molecular motion) to kinetic (piston motion) transfer of energy is substantially more efficient than the calorie transfer in heating and expanding gasses to move the piston.
Extreme fuel mileage is possible with such fuel-air detonation motors. There are no "laws of physics" being broken with them. You can demonstrate the difference between "burning slowly and heating air" (the current method of fuel usage in production motors) and detonation with simple experiments:
Put a small amount of liquid fuel in an enclosed cylinder with air and a moveable piston. Ignite and burn the fuel and air and observe the motion of the piston as the gasses are heated and expand.
Vaporize that same small amount of fuel and mix it with the air in the same cylinder/piston set-up. Ignite it and watch what the detonation does to the moveable piston. (Stand back for that part of the experiment.)
Direct molecular kinetic energy transfer to the piston in the form of the shock-wave from the detonating fuel-air mixture does more work than caloric transfer and gas expansion of "burning."
There is nothing ridiculous about it.
So... Does your measure of fuel contain that amount of energy or not? And if your measure of fuel has the required amount of energy to only accomplish a given task, does it have the excess amount needed to counteract that energy absorbed or lost by the engine and ancillary components?
Math is pretty easy and the answer is either yes or no. In the case of the OP I'd have to say no.
quote:Originally posted by nord
Here we go again. Gasoline or any fuel contains a certain number of calories per measure. Since we're talking a gasoline engine here I'll limit my comments to this type of engine:
The first thing we need to understand is that a gasoline engine in order to function properly needs to be fed both fuel and air in the proper ratio. In modern vehicles this ratio is achieved by electronic measurement of air, fuel, and temperature. This allows for a very controlled burn in the cylinder.
The second thing we need to understand is that gasoline is being atomized before entering the cylinder, or as it enters the cylinder depending upon the delivery system. In old vehicles we have a carburetor. Air being drawn into the cylinder is directed through a venturi. The low pressure and increased speed of the air cause fuel to be forced through a jet into the intake airstream where liquid fuel is vaporized and mixed with the air. Jetting determines the proper air/fuel ratio.
Newer vehicles address fueling somewhat differently in that the fuel is electronically injected into the airstream and the mixture is controlled via the ECU. So single port, multi-port, or direct injection. In all cases a computer controls the air/fuel ratio.
Now to the engine itself... Gasoline engines will run outside the optimum air/fuel ratio. Too rich and unburned fuel will be a part of the exhaust component. Power will be greatly compromised and the engine will not perform well. Leaning will first result in slightly increased performance but cylinder temps will quickly go into the danger zone. Past a point the engine will not have enough fuel to continue to operate with a resulting stall.
Now to the claim set out in the OP... A gasoline engine returns less than 30% efficiency in the real world. In other words about 2/3 of the fuel used is wasted. The waste being in heat, internal friction, and a multitude of other factors. No matter what we do it takes a certain amount of energy just to keep the mill turning over.
Further, it takes a certain amount of energy (calories) to do a specific job. This is the reason that while alcohol burns cleaner than gasoline, it takes roughly twice as much to do the same amount of work as alcohol contains about half the calories per unit compared to gasoline.
Claims of unbelievable fuel economy are just that... Unbelievable! Certainly it's possible to lean a motor at idle to a point where it will still run thereby using less fuel than normal. But there must be enough energy to keep that engine running. And should that engine be required to do any real work it will need the fuel energy required for the task. This aside from the fact that an aggressively lean condition will result in engine damage.
Given that the internal combustion engine is inefficient by its very nature and given that even at idle there exists a certain level of energy required to keep things turning, the claims made are ridiculous.
You can detect the "pinging" as that motor is running -- that is the fuel/air mixture detonating. Production motors are designed to utilize fuel by burning it and causing the (relatively) slow expansion of gasses in the cylinder.
Detonating a fuel/air mixture (in a properly tuned motor) is utilizing the kinetic energy of the gas molecules directly impinging against the piston. This detonation -- and subsequent kinetic (from molecular motion) to kinetic (piston motion) transfer of energy is substantially more efficient than the calorie transfer in heating and expanding gasses to move the piston.
Extreme fuel mileage is possible with such fuel-air detonation motors. There are no "laws of physics" being broken with them. You can demonstrate the difference between "burning slowly and heating air" (the current method of fuel usage in production motors) and detonation with simple experiments:
Put a small amount of liquid fuel in an enclosed cylinder with air and a moveable piston. Ignite and burn the fuel and air and observe the motion of the piston as the gasses are heated and expand.
Vaporize that same small amount of fuel and mix it with the air in the same cylinder/piston set-up. Ignite it and watch what the detonation does to the moveable piston. (Stand back for that part of the experiment.)
Direct molecular kinetic energy transfer to the piston in the form of the shock-wave from the detonating fuel-air mixture does more work than caloric transfer and gas expansion of "burning."
There is nothing ridiculous about it.
When I was a wee little Lad I did a bit of street racing, I know the biggest thing to bust up my engines was the dreaded lean fuel knock. At the rpm's the engines ran it was to late when you could hear it, things like spark plugs blown out of the heads, rings ripped off and pistons with nice holes blown through them were the normal result. Oh and the awesome looking flame cutting (head and block) where the head gasket blew out.
The detonation in a hot engine is mucho bad, not sure how I can understand it being more efficient.
I was taught that the "ping" you hear is from the two flame walls striking, one from ignition and the other from the "pre ignition source."
May I ask what type of internal combustion engine can absorb and utilize the temperature and explosive force of'
Direct molecular kinetic energy transfer to the piston in the form of the shock-wave from the detonating fuel-air mixture does more work than caloric transfer and gas expansion of "burning."
Not trying to be a jerk very curious is all.
Thanks David.
You may, indeed, ask the question and the answer is a diesel engine. A diesel is a compression ignition design and diesel fuel yields more energy per measure than gasoline. Components are built heavier to absorb and use this type of ignition.
Nord, can you elaborate on the potential energy of gasoline? What is the absolute highest amount of energy that can be obtained by gas? And is this number 3.3 times higher than when you state that a typical IC engine is 30% efficient?
Can we start by meeting the cafe standard for 2020 first with proven claims.
GGE Calculated for Gasoline in US Gallons at 114000 BTU per Gallon,
or 7594 kilocalories per litre[2]
Fuel - Liquid, US Gallons GGE GGE % BTU/Gal kWh/Gal HP-hr/Gal Cal/litre
Gasoline (base)[3] 1.0000 100.00% 114,000
Methanol fuel (M100)[5] 2.0100 49.75% 56,800 16.62 22.28 3778.1
Ethanol fuel (E100)[5] 1.5000 66.67% 76,100 22.27 29.85 5062.7
Ethanol (E85)[5] 1.3900 71.94% 81,800 24.04 32.23 5463.3
So the answer to your question assuming the use of an internal combustion engine at about 30% efficiency you'll need 3 BTU's in total for every 1 BTU required for the actual work.
I hope this answers your question.
quote:Originally posted by competentone
quote:Originally posted by nord
Here we go again. Gasoline or any fuel contains a certain number of calories per measure. Since we're talking a gasoline engine here I'll limit my comments to this type of engine:
The first thing we need to understand is that a gasoline engine in order to function properly needs to be fed both fuel and air in the proper ratio. In modern vehicles this ratio is achieved by electronic measurement of air, fuel, and temperature. This allows for a very controlled burn in the cylinder.
The second thing we need to understand is that gasoline is being atomized before entering the cylinder, or as it enters the cylinder depending upon the delivery system. In old vehicles we have a carburetor. Air being drawn into the cylinder is directed through a venturi. The low pressure and increased speed of the air cause fuel to be forced through a jet into the intake airstream where liquid fuel is vaporized and mixed with the air. Jetting determines the proper air/fuel ratio.
Newer vehicles address fueling somewhat differently in that the fuel is electronically injected into the airstream and the mixture is controlled via the ECU. So single port, multi-port, or direct injection. In all cases a computer controls the air/fuel ratio.
Now to the engine itself... Gasoline engines will run outside the optimum air/fuel ratio. Too rich and unburned fuel will be a part of the exhaust component. Power will be greatly compromised and the engine will not perform well. Leaning will first result in slightly increased performance but cylinder temps will quickly go into the danger zone. Past a point the engine will not have enough fuel to continue to operate with a resulting stall.
Now to the claim set out in the OP... A gasoline engine returns less than 30% efficiency in the real world. In other words about 2/3 of the fuel used is wasted. The waste being in heat, internal friction, and a multitude of other factors. No matter what we do it takes a certain amount of energy just to keep the mill turning over.
Further, it takes a certain amount of energy (calories) to do a specific job. This is the reason that while alcohol burns cleaner than gasoline, it takes roughly twice as much to do the same amount of work as alcohol contains about half the calories per unit compared to gasoline.
Claims of unbelievable fuel economy are just that... Unbelievable! Certainly it's possible to lean a motor at idle to a point where it will still run thereby using less fuel than normal. But there must be enough energy to keep that engine running. And should that engine be required to do any real work it will need the fuel energy required for the task. This aside from the fact that an aggressively lean condition will result in engine damage.
Given that the internal combustion engine is inefficient by its very nature and given that even at idle there exists a certain level of energy required to keep things turning, the claims made are ridiculous.
You can detect the "pinging" as that motor is running -- that is the fuel/air mixture detonating. Production motors are designed to utilize fuel by burning it and causing the (relatively) slow expansion of gasses in the cylinder.
Detonating a fuel/air mixture (in a properly tuned motor) is utilizing the kinetic energy of the gas molecules directly impinging against the piston. This detonation -- and subsequent kinetic (from molecular motion) to kinetic (piston motion) transfer of energy is substantially more efficient than the calorie transfer in heating and expanding gasses to move the piston.
Extreme fuel mileage is possible with such fuel-air detonation motors. There are no "laws of physics" being broken with them. You can demonstrate the difference between "burning slowly and heating air" (the current method of fuel usage in production motors) and detonation with simple experiments:
Put a small amount of liquid fuel in an enclosed cylinder with air and a moveable piston. Ignite and burn the fuel and air and observe the motion of the piston as the gasses are heated and expand.
Vaporize that same small amount of fuel and mix it with the air in the same cylinder/piston set-up. Ignite it and watch what the detonation does to the moveable piston. (Stand back for that part of the experiment.)
Direct molecular kinetic energy transfer to the piston in the form of the shock-wave from the detonating fuel-air mixture does more work than caloric transfer and gas expansion of "burning."
There is nothing ridiculous about it.
When I was a wee little Lad I did a bit of street racing, I know the biggest thing to bust up my engines was the dreaded lean fuel knock. At the rpm's the engines ran it was to late when you could hear it, things like spark plugs blown out of the heads, rings ripped off and pistons with nice holes blown through them were the normal result. Oh and the awesome looking flame cutting (head and block) where the head gasket blew out.
The detonation in a hot engine is mucho bad, not sure how I can understand it being more efficient.
I was taught that the "ping" you hear is from the two flame walls striking, one from ignition and the other from the "pre ignition source."
May I ask what type of internal combustion engine can absorb and utilize the temperature and explosive force of'
Direct molecular kinetic energy transfer to the piston in the form of the shock-wave from the detonating fuel-air mixture does more work than caloric transfer and gas expansion of "burning."
Not trying to be a jerk very curious is all.
Thanks David.
Yes, "pinging" (pre-ignition of the gas/fuel mixture) is destructive to ordinary production motors designed to (relatively slowly) burn the fuel-air mixture, but the "detonation" is not working the same in a motor designed to use it.
The speed (and stroke) of the pistons in the motor need to match the shock-wave of the detonating fuel-air mixture if the molecular kinetic energy is going to be transferred efficiently to the piston.
The destructive power you describe from detonation of the fuel-air mixture in a motor not designed for it is a demonstration of the molecular kinetic energy available. You just have to capture that energy properly, not "fight it" -- that involves matching the rate of motion of the piston on the down-stroke to the shock-wave. This translates into a motor -- at least when it is running at its peak efficiency -- with a very limited power range. There is a "sweet spot" in timing such motors -- where the extremely lean fuel-air mixture detonates and the shock-wave imparts its energy to the piston at just the right point in the down-stroke.
People (often "engineers" who can only think in the terms they've been taught) can't get themselves away from thinking about "burning" fuel and "heating gasses" -- that's not what is happening in a detonation motor. They keep telling (the mostly science-ignorant) public, "It can't be done!" and yet, through the decades, inventors and tinkerers have demonstrated it (and have destroyed their fair share of motors along the way).
quote:Originally posted by EhlerDave
quote:Originally posted by competentone
quote:Originally posted by nord
Here we go again. Gasoline or any fuel contains a certain number of calories per measure. Since we're talking a gasoline engine here I'll limit my comments to this type of engine:
The first thing we need to understand is that a gasoline engine in order to function properly needs to be fed both fuel and air in the proper ratio. In modern vehicles this ratio is achieved by electronic measurement of air, fuel, and temperature. This allows for a very controlled burn in the cylinder.
The second thing we need to understand is that gasoline is being atomized before entering the cylinder, or as it enters the cylinder depending upon the delivery system. In old vehicles we have a carburetor. Air being drawn into the cylinder is directed through a venturi. The low pressure and increased speed of the air cause fuel to be forced through a jet into the intake airstream where liquid fuel is vaporized and mixed with the air. Jetting determines the proper air/fuel ratio.
Newer vehicles address fueling somewhat differently in that the fuel is electronically injected into the airstream and the mixture is controlled via the ECU. So single port, multi-port, or direct injection. In all cases a computer controls the air/fuel ratio.
Now to the engine itself... Gasoline engines will run outside the optimum air/fuel ratio. Too rich and unburned fuel will be a part of the exhaust component. Power will be greatly compromised and the engine will not perform well. Leaning will first result in slightly increased performance but cylinder temps will quickly go into the danger zone. Past a point the engine will not have enough fuel to continue to operate with a resulting stall.
Now to the claim set out in the OP... A gasoline engine returns less than 30% efficiency in the real world. In other words about 2/3 of the fuel used is wasted. The waste being in heat, internal friction, and a multitude of other factors. No matter what we do it takes a certain amount of energy just to keep the mill turning over.
Further, it takes a certain amount of energy (calories) to do a specific job. This is the reason that while alcohol burns cleaner than gasoline, it takes roughly twice as much to do the same amount of work as alcohol contains about half the calories per unit compared to gasoline.
Claims of unbelievable fuel economy are just that... Unbelievable! Certainly it's possible to lean a motor at idle to a point where it will still run thereby using less fuel than normal. But there must be enough energy to keep that engine running. And should that engine be required to do any real work it will need the fuel energy required for the task. This aside from the fact that an aggressively lean condition will result in engine damage.
Given that the internal combustion engine is inefficient by its very nature and given that even at idle there exists a certain level of energy required to keep things turning, the claims made are ridiculous.
You can detect the "pinging" as that motor is running -- that is the fuel/air mixture detonating. Production motors are designed to utilize fuel by burning it and causing the (relatively) slow expansion of gasses in the cylinder.
Detonating a fuel/air mixture (in a properly tuned motor) is utilizing the kinetic energy of the gas molecules directly impinging against the piston. This detonation -- and subsequent kinetic (from molecular motion) to kinetic (piston motion) transfer of energy is substantially more efficient than the calorie transfer in heating and expanding gasses to move the piston.
Extreme fuel mileage is possible with such fuel-air detonation motors. There are no "laws of physics" being broken with them. You can demonstrate the difference between "burning slowly and heating air" (the current method of fuel usage in production motors) and detonation with simple experiments:
Put a small amount of liquid fuel in an enclosed cylinder with air and a moveable piston. Ignite and burn the fuel and air and observe the motion of the piston as the gasses are heated and expand.
Vaporize that same small amount of fuel and mix it with the air in the same cylinder/piston set-up. Ignite it and watch what the detonation does to the moveable piston. (Stand back for that part of the experiment.)
Direct molecular kinetic energy transfer to the piston in the form of the shock-wave from the detonating fuel-air mixture does more work than caloric transfer and gas expansion of "burning."
There is nothing ridiculous about it.
When I was a wee little Lad I did a bit of street racing, I know the biggest thing to bust up my engines was the dreaded lean fuel knock. At the rpm's the engines ran it was to late when you could hear it, things like spark plugs blown out of the heads, rings ripped off and pistons with nice holes blown through them were the normal result. Oh and the awesome looking flame cutting (head and block) where the head gasket blew out.
The detonation in a hot engine is mucho bad, not sure how I can understand it being more efficient.
I was taught that the "ping" you hear is from the two flame walls striking, one from ignition and the other from the "pre ignition source."
May I ask what type of internal combustion engine can absorb and utilize the temperature and explosive force of'
Direct molecular kinetic energy transfer to the piston in the form of the shock-wave from the detonating fuel-air mixture does more work than caloric transfer and gas expansion of "burning."
Not trying to be a jerk very curious is all.
Thanks David.
Yes, "pinging" (pre-ignition of the gas/fuel mixture) is destructive to ordinary production motors designed to (relatively slowly) burn the fuel-air mixture, but the "detonation" is not working the same in a motor designed to use it.
The speed (and stroke) of the pistons in the motor need to match the shock-wave of the detonating fuel-air mixture if the molecular kinetic energy is going to be transferred efficiently to the piston.
The destructive power you describe from detonation of the fuel-air mixture in a motor not designed for it is a demonstration of the molecular kinetic energy available. You just have to capture that energy properly, not "fight it" -- that involves matching the rate of motion of the piston on the down-stroke to the shock-wave. This translates into a motor -- at least when it is running at its peak efficiency -- with a very limited power range. There is a "sweet spot" in timing such motors -- where the extremely lean fuel-air mixture detonates and the shock-wave imparts its energy to the piston at just the right point in the down-stroke.
People (often "engineers" who can only think in the terms they've been taught) can't get themselves away from thinking about "burning" fuel and "heating gasses" -- that's not what is happening in a detonation motor. They keep telling (the mostly science-ignorant) public, "It can't be done!" and yet, through the decades, inventors and tinkerers have demonstrated it (and have destroyed their fair share of motors along the way).
What you say is true. What Nord said was true, when speaking of diesel engines. I know gas engines are timed Before Top Dead Center (BTDC). That is why the destruction is so bad for lean knock. The piston is still being pushed up while the pressure is trying to force it back down at the same time. This is not a good thing.[8D]
The diesel engine is timed After Top Dead Center (ATDC) so in that case the piston is on the way down before the injector fires the fuel into the heated air for ignition.
The thing is the OP was about gasoline. To top off the gas debate back when I was racing all cars came from the factory with a MPG that was set with fuel that could not be bought at a pump, never did think tat was right.
As it is right now I have an old Ford 429, on pump gas with my timing set at 10 degrees it "pings, knocks" at idle. Modern fuel is not so good for older engines.
I have found all the info in this thread very interesting,
Thanks to everyone who has contributed.
Don't all gas engines run on fumes?
Allen
Yes they do![;)]
quote:Originally posted by EhlerDave
quote:Originally posted by competentone
quote:Originally posted by nord
Here we go again. Gasoline or any fuel contains a certain number of calories per measure. Since we're talking a gasoline engine here I'll limit my comments to this type of engine:
The first thing we need to understand is that a gasoline engine in order to function properly needs to be fed both fuel and air in the proper ratio. In modern vehicles this ratio is achieved by electronic measurement of air, fuel, and temperature. This allows for a very controlled burn in the cylinder.
The second thing we need to understand is that gasoline is being atomized before entering the cylinder, or as it enters the cylinder depending upon the delivery system. In old vehicles we have a carburetor. Air being drawn into the cylinder is directed through a venturi. The low pressure and increased speed of the air cause fuel to be forced through a jet into the intake airstream where liquid fuel is vaporized and mixed with the air. Jetting determines the proper air/fuel ratio.
Newer vehicles address fueling somewhat differently in that the fuel is electronically injected into the airstream and the mixture is controlled via the ECU. So single port, multi-port, or direct injection. In all cases a computer controls the air/fuel ratio.
Now to the engine itself... Gasoline engines will run outside the optimum air/fuel ratio. Too rich and unburned fuel will be a part of the exhaust component. Power will be greatly compromised and the engine will not perform well. Leaning will first result in slightly increased performance but cylinder temps will quickly go into the danger zone. Past a point the engine will not have enough fuel to continue to operate with a resulting stall.
Now to the claim set out in the OP... A gasoline engine returns less than 30% efficiency in the real world. In other words about 2/3 of the fuel used is wasted. The waste being in heat, internal friction, and a multitude of other factors. No matter what we do it takes a certain amount of energy just to keep the mill turning over.
Further, it takes a certain amount of energy (calories) to do a specific job. This is the reason that while alcohol burns cleaner than gasoline, it takes roughly twice as much to do the same amount of work as alcohol contains about half the calories per unit compared to gasoline.
Claims of unbelievable fuel economy are just that... Unbelievable! Certainly it's possible to lean a motor at idle to a point where it will still run thereby using less fuel than normal. But there must be enough energy to keep that engine running. And should that engine be required to do any real work it will need the fuel energy required for the task. This aside from the fact that an aggressively lean condition will result in engine damage.
Given that the internal combustion engine is inefficient by its very nature and given that even at idle there exists a certain level of energy required to keep things turning, the claims made are ridiculous.
You can detect the "pinging" as that motor is running -- that is the fuel/air mixture detonating. Production motors are designed to utilize fuel by burning it and causing the (relatively) slow expansion of gasses in the cylinder.
Detonating a fuel/air mixture (in a properly tuned motor) is utilizing the kinetic energy of the gas molecules directly impinging against the piston. This detonation -- and subsequent kinetic (from molecular motion) to kinetic (piston motion) transfer of energy is substantially more efficient than the calorie transfer in heating and expanding gasses to move the piston.
Extreme fuel mileage is possible with such fuel-air detonation motors. There are no "laws of physics" being broken with them. You can demonstrate the difference between "burning slowly and heating air" (the current method of fuel usage in production motors) and detonation with simple experiments:
Put a small amount of liquid fuel in an enclosed cylinder with air and a moveable piston. Ignite and burn the fuel and air and observe the motion of the piston as the gasses are heated and expand.
Vaporize that same small amount of fuel and mix it with the air in the same cylinder/piston set-up. Ignite it and watch what the detonation does to the moveable piston. (Stand back for that part of the experiment.)
Direct molecular kinetic energy transfer to the piston in the form of the shock-wave from the detonating fuel-air mixture does more work than caloric transfer and gas expansion of "burning."
There is nothing ridiculous about it.
When I was a wee little Lad I did a bit of street racing, I know the biggest thing to bust up my engines was the dreaded lean fuel knock. At the rpm's the engines ran it was to late when you could hear it, things like spark plugs blown out of the heads, rings ripped off and pistons with nice holes blown through them were the normal result. Oh and the awesome looking flame cutting (head and block) where the head gasket blew out.
The detonation in a hot engine is mucho bad, not sure how I can understand it being more efficient.
I was taught that the "ping" you hear is from the two flame walls striking, one from ignition and the other from the "pre ignition source."
May I ask what type of internal combustion engine can absorb and utilize the temperature and explosive force of'
Direct molecular kinetic energy transfer to the piston in the form of the shock-wave from the detonating fuel-air mixture does more work than caloric transfer and gas expansion of "burning."
Not trying to be a jerk very curious is all.
Thanks David.
Yes, "pinging" (pre-ignition of the gas/fuel mixture) is destructive to ordinary production motors designed to (relatively slowly) burn the fuel-air mixture, but the "detonation" is not working the same in a motor designed to use it.
The speed (and stroke) of the pistons in the motor need to match the shock-wave of the detonating fuel-air mixture if the molecular kinetic energy is going to be transferred efficiently to the piston.
The destructive power you describe from detonation of the fuel-air mixture in a motor not designed for it is a demonstration of the molecular kinetic energy available. You just have to capture that energy properly, not "fight it" -- that involves matching the rate of motion of the piston on the down-stroke to the shock-wave. This translates into a motor -- at least when it is running at its peak efficiency -- with a very limited power range. There is a "sweet spot" in timing such motors -- where the extremely lean fuel-air mixture detonates and the shock-wave imparts its energy to the piston at just the right point in the down-stroke.
People (often "engineers" who can only think in the terms they've been taught) can't get themselves away from thinking about "burning" fuel and "heating gasses" -- that's not what is happening in a detonation motor. They keep telling (the mostly science-ignorant) public, "It can't be done!" and yet, through the decades, inventors and tinkerers have demonstrated it (and have destroyed their fair share of motors along the way).
One of the things you can do to raise the 'octane' of pump gas is to add some diesel fuel (extermination required[;)]). It will also stop of limit 'vapor lock' in small engines like chainsaws.
The point made by the lack of efficiency due to the heat loss could be remedied with a timed injection of water about mid way through the combustion process (behind the flame front). We have the technology to do this easily, both in hardware and software, but for some reason no one has even mentioned it as far as I can see![?]
Extreme fuel mileage is possible with such fuel-air detonation motors. There are no "laws of physics" being broken with them. You can demonstrate the difference between "burning slowly and heating air" (the current method of fuel usage in production motors) and detonation with simple experiments:
Put a small amount of liquid fuel in an enclosed cylinder with air and a moveable piston. Ignite and burn the fuel and air and observe the motion of the piston as the gasses are heated and expand.
Vaporize that same small amount of fuel and mix it with the air in the same cylinder/piston set-up. Ignite it and watch what the detonation does to the moveable piston. (Stand back for that part of the experiment.)
Direct molecular kinetic energy transfer to the piston in the form of the shock-wave from the detonating fuel-air mixture does more work than caloric transfer and gas expansion of "burning."
There is nothing ridiculous about it.In each case it's molecules striking the piston at high speed which creates pressure.
Your experiment proves absolutely nothing because a piston is not equally free to move in a gas engine. When the plug fires, the piston pin is travelling mostly sideways relative to the piston's bore and there is plenty of time for the fuel to burn.
There's not really more energy with vapor. It just gets released faster. In your experiment, if you held back the piston with the liquid fuel for a moment while the fuel burned, it would fly about as far as the one with vapor.
That's assuming you're talking about a small amount. You could get more liquid fuel into the cylinder without excessive pressure because it takes up less space and has the ability to cool the combustion chamber a bit which would reduce knock.
With fuel droplets, it's the same amount of energy being released slightly more slowly. It's imparting its work to the piston in the same way, by molecules striking it at high speed.
A portion of the fuel is vaporized by striking the hot surfaces inside the combustion chamber so it's not as different as your theory suggests.
People (often "engineers" who can only think in the terms they've been taught) can't get themselves away from thinking about "burning" fuel and "heating gasses" -- that's not what is happening in a detonation motor. What is happening in a detonation motor if not heat causing increased pressure? What gives the molecules so much kinetic energy?
Engineers don't simply learn how current technology works. They have a background in chemistry, physics, fluid mechanics, thermodynamics, and other sciences required to understand the principles of what's going on.
Lacking that background causes some people not to see how something is not significantly different even though they have been told it is.
quote:Originally posted by competentone
People (often "engineers" who can only think in the terms they've been taught) can't get themselves away from thinking about "burning" fuel and "heating gasses" -- that's not what is happening in a detonation motor. What is happening in a detonation motor if not heat causing increased pressure? What gives the molecules so much kinetic energy?
Engineers don't simply learn how current technology works. They have a background in chemistry, physics, fluid mechanics, thermodynamics, and other sciences required to understand the principles of what's going on.
Sometimes, people don't really know what they're talking about and they think something should work for reasons that just don't fly.
Gas molecules in detonation, moving in a "shock wave" (yes, it is still "heat" driven -- I never suggested otherwise) is different than the disoriented, random motion (heat driven again) when building pressure by "burning" fuel.
I trust my own eyes, and other senses (and my understanding of physics, chemistry and mechanics) in determining that certain technologies you claim "don't work" actually do.
I also don't let myself be side-tracked by the "nuttiness" that can surround this subject of extreme fuel mileage, nor do not accept the suggestion that current production motors represent "the most efficient design possible" for maximizing fuel efficiency.
I trust my own eyes, and other senses (and my understanding of physics, chemistry and mechanics) in determining that certain technologies you claim "don't work" actually do.
I also don't let myself be side-tracked by the "nuttiness" that can surround this subject of extreme fuel mileage, nor do not accept the suggestion that current production motors represent "the most efficient design possible" for maximizing fuel efficiency.
How does anything you say impart more energy to a piston than ordinary engines? Please be as specific as you can.
What do you mean when you say you trust your senses? When have you seen any combustion inside an engine?
quote:Originally posted by competentoneGas molecules in detonation, moving in a "shock wave" (yes, it is still "heat" driven -- I never suggested otherwise) is different than the disoriented, random motion (heat driven again) when building pressure by "burning" fuel.
I trust my own eyes, and other senses (and my understanding of physics, chemistry and mechanics) in determining that certain technologies you claim "don't work" actually do.
I also don't let myself be side-tracked by the "nuttiness" that can surround this subject of extreme fuel mileage, nor do not accept the suggestion that current production motors represent "the most efficient design possible" for maximizing fuel efficiency.
How does anything you say impart more energy to a piston than ordinary engines? Please be as specific as you can.
What do you mean when you say you trust your senses? When have you seen any combustion inside an engine?
I'm not going to give you a full lesson about energy in a wave form vs. other forms -- if you claim a good general understanding of the sciences, you should already understand it -- but will ask you to consider how it is possible you could feel the effect of a certain amount of energy transmitted, as a sound wave, through a tube a mile long, but would not perceive it at all, if the same amount of energy only caused random molecular motion in the air molecules at one end of the tube?
"Energy" -- the "ability to do work" -- of the gas molecules needs to be imparted to the piston for the motor to work. The more efficiently the energy in the gas molecules can perform work on the piston, the more efficiently the motor will operate.
My point is, the directional energy of a shock-wave (essentially a "sound wave") can be more efficient at imparting its energy to the piston than the random, multi-directional energy of generalized "pressure" (created by heating gas through "burning" fuel).
As for your comments about me relying on my senses, I hope you are just trying to be "funny." If you don't understand that instruments used to measure (heat, pressure, energy, etc.) are just tools used to enhance our senses then I fear I am wasting my time trying to discuss any scientific subject with you.
quote:Originally posted by EhlerDave As it is right now I have an old Ford 429, on pump gas with my timing set at 10 degrees it "pings, knocks" at idle. Modern fuel is not so good for older engines.Can't you shim the cylinder heads somehow, maybe by using two head gaskets?
Right now my engine has flat topped pistons, I could get a set that are dished but in so doing would drop my compression and the power this thing creates. They make solid copper head gaskets for it, I bet they make them in different thicknesses just for that.
I have a few bottles of lead and octane booster (made by stp years ago) I got them from my old job. They had a gas air compressor that ran 2 B&M superchargers that were the size of a v-6 each. That thing needed the boost and extra lead, then the refineries would not let us run it so I got all the additive.
I have no idea of what speed the car will run, my speedo does not go to 188. [:D] But I have 30 in tall rear tires and the rear gears are 2.75, it will fly. [8D]
When I drive on the highway I get a solid 6 to 8 mpg, so it does not even get started very often. And as it is I am afraid I have a crack in a head so until that is fixed its not leaving the yard.
quote:Originally posted by SoreShoulder
quote:Originally posted by competentoneGas molecules in detonation, moving in a "shock wave" (yes, it is still "heat" driven -- I never suggested otherwise) is different than the disoriented, random motion (heat driven again) when building pressure by "burning" fuel.
I trust my own eyes, and other senses (and my understanding of physics, chemistry and mechanics) in determining that certain technologies you claim "don't work" actually do.
I also don't let myself be side-tracked by the "nuttiness" that can surround this subject of extreme fuel mileage, nor do not accept the suggestion that current production motors represent "the most efficient design possible" for maximizing fuel efficiency.
How does anything you say impart more energy to a piston than ordinary engines? Please be as specific as you can.
What do you mean when you say you trust your senses? When have you seen any combustion inside an engine?
I'm not going to give you a full lesson about energy in a wave form vs. other forms -- if you claim a good general understanding of the sciences, you should already understand it -- but will ask you to consider how it is possible you could feel the effect of a certain amount of energy transmitted, as a sound wave, through a tube a mile long, but would not perceive it at all, if the same amount of energy only caused random molecular motion in the air molecules at one end of the tube?
"Energy" -- the "ability to do work" -- of the gas molecules needs to be imparted to the piston for the motor to work. The more efficiently the energy in the gas molecules can perform work on the piston, the more efficiently the motor will operate.
My point is, the directional energy of a shock-wave (essentially a "sound wave") can be more efficient at imparting its energy to the piston than the random, multi-directional energy of generalized "pressure" (created by heating gas through "burning" fuel).
As for your comments about me relying on my senses, I hope you are just trying to be "funny." If you don't understand that instruments used to measure (heat, pressure, energy, etc.) are just tools used to enhance our senses then I fear I am wasting my time trying to discuss any scientific subject with you.
What instruments did you use on what experiment, and what was the outcome?
I think you could sense pressure at the end of a mile long tube, whereas a sound wave would probably dissipate long before it reached the end. Perhaps I need that full lesson.
Besides, the flame front from gaseous combustion would be round and most of the molecules would not hit the piston head on. You'd wind up with a cylinder full of pressure much like a liquid fuel engine, only you could probably advance your timing a bit.
Once calculated, then the answer is either that it's possible or impossible based on the energy required versus the energy contained in the fuel.
So once again I'll make it easy...
Let's say our measure of gasoline contains 1000 BTU's of potential energy. The task at hand demands 1000 BTU's of energy. But we're feeding a gasoline engine the fuel and it's only about 30% efficient. It doesn't take a math wiz to determine that the job won't get done. And it won't get done unless we either add two measures of fuel to the one we already have, or we somehow make our engine 100% efficient.
But back to the OP. Only one question really needs answered. Does the gallon of gasoline contain the amount of energy required to do the task at hand?
And remember that even if it does (not likely), then is there enough excess energy to cover that wasted by our engine and associated energy wasting components?
Don't allow yourselves to be sidetracked by technology and wishful thinking. Neither can add energy to a measure of gasoline or any other fuel. And more efficient engines? Bring 'em on! Produce a reliable internal combustion engine that will return even 40% efficiency and you'll be in line for a Nobel Prize!
A given measure of fuel (any fuel) contains a certain amount of energy. (Differing amounts of energy for differing fuels.) The problem lies in the technical ability to use our fuel efficiently. Typically we think of a reciprocating internal combustion engine to do this conversion and therein lies a huge problem. Should you be yet unaware, such engines are plagued by friction losses and produce heat that must be dissipated. Due to this fact we generally figure about a 30% return on our total energy input within a very few percentage points one way or the other.
Place aside your focus on fuel. It really is of no consequence when looking at the whole picture. Some fuels are easier and cleaner to use than others. Some produce less pollution and others more. All the same we come down to the potential energy residing within a given measure of fuel and the conversion of that energy into a given task.
If I were to use the analogy of watering your tomatoes with but one gallon of water this concept might be a bit easier to understand. In one case you might simply dump the contents starting at one end of the row and ending when the water ran out. If you happen to be a bit more prudent, then you might soak each individual plant carefully and the water would extend to more plants in the row. In the final case you might use the drip method and water each plant according to its exact needs. This would considerably extend your ability to water your plants with that single gallon of water.
In the above example your gallon of water (fuel) remains constant but your use of the water changes. When you micro-manage your water supply you extend its use. But when you have a thousand foot row of tomatoes and only a gallon of water it really doesn't matter how carefully you manage things as there just isn't enough to do the job.
And thus concludes the lesson. Be as parsimonious as you wish but when the water runs out and you're only 33% of the way done on a given task, then nothing short of another two gallons of water will get the job done. It's that simple.
Place aside your focus on fuel. It really is of no consequence when looking at the whole picture. Some fuels are easier and cleaner to use than others. Some produce less pollution and others more. All the same we come down to the potential energy residing within a given measure of fuel and the conversion of that energy into a given task.
Consider for a moment that "task" is to move a bullet to a velocity, using a given amount of smokeless powder, so it has sufficient energy to do damage to an animal we want to kill.
If you designed a device trying to accomplish this task using an open container to burn the powder, and then failed to transfer sufficient energy to the bullet, would you claim, "See! It won't work; there is only a limited amount of energy in the powder; I have released all the energy, but cannot propel the bullet to a useful velocity!"
That is essentially the claim you are making against those (like myself) who are saying there are ways to more efficiently transfer the energy from fuel to move a piston in a motor.
Again, I'm talking about a motor designed to utilize a fuel/air mixture being detonated as opposed to being "burned." The difference can be compared to the difference of burning smokeless-powder unconfined vs. burning it confined within a firearm chamber. While the same amount of energy is involved, the ability of that energy to be transferred to perform some task depends on how the device is structured to utilize that energy release.
The original post of this thread shows a video of someone running a motor using fuel vapor -- that, in-and-of-itself, does not create an extremely efficient motor, but turning gasoline to vapor and creating an extremely lean fuel-air ratio is required before one can detonate a gasoline-air mixture. The detonation -- along with proper motor design to utilize the detonating fuel effectively -- can result in efficiencies (measured in MPG of fuel consumption) that is extreme when compared to the current fuel consumption for production motors/cars.
There is no "magic"; no one is "breaking laws of physics." The same amount of energy exists in the fuel. The difference is in the manner that energy is released and transferred to perform work (on the piston within the motor).
Good heavens man, don't you read?...Place aside your focus on fuel. It really is of no consequence when looking at the whole picture. That's why I said why DON'T engines running on propane or lpg get better economy.
The original post of this thread shows a video of someone running a motor using fuel vapor -- that, in-and-of-itself, does not create an extremely efficient motor, but turning gasoline to vapor and creating an extremely lean fuel-air ratio is required before one can detonate a gasoline-air mixture. The detonation -- along with proper motor design to utilize the detonating fuel effectively -- can result in efficiencies (measured in MPG of fuel consumption) that is extreme when compared to the current fuel consumption for production motors/cars.
There is no "magic"; no one is "breaking laws of physics." The same amount of energy exists in the fuel. The difference is in the manner that energy is released and transferred to perform work (on the piston within the motor).It's actually like a fast burning powder vs a slow burning powder in a round where the crimp doesn't open until the powder is largely consumed i.e. not much difference.
There's not really a different principle.
High explosive detonation in a solid explosive can shatter metal because of the speed of the shock wave but in a mixture of air and gaseous fuel it is not that fast.
It is not that different than an engine using liquid fuel because a portion of the fuel charge vaporizes when it hits the piston and combustion chamber. The rest burns before the piston changes direction and starts moving downward very much. It vaporizes before it burns as well.
Having it all in vapor form may create a single flame front or shock wave but the fact that the average motion of the molecules is in a ball outward away from the spark plug doesn't mean there's a different form of energy transfer. There are still molecules bouncing off one another and the surrounding exhaust and unburned fuel-air mix and combustion chamber walls.
Then the molecules of exhaust strike the piston, cylinder walls, and combustion chamber as well as one another and continue to randomly rebound just like any gasoline engine.
Increasing the suddenness of the energy release is not desirable because it leads to more stress to the parts and more energy dissipated in the harmonic balancer.
Like I said before, why don't engines running on LPG or propane produce unusually high fuel economy? They get slightly better economy because they crowd out a portion of the intake air and reduce throttling losses.
You think there's a different principle but there isn't.