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quote:Originally posted by SoreShoulder
The fellow in the video seemed to have a means of tuning his fuel delivery.
In certain situations these experimenters may have gotten a few minutes of apparently very efficient running if they didn't mess with the engine too much.
They may have failed to realize that the fuel in a normal engine does vaporize and in so doing, it cools the piston and combustion chamber.
They may actually be vaporizing their crankcase oil and fueling their engine with it through the PCV valve.
Gaseous fuel makes an engine run hotter!
Then, the gasoline vaporizer system is tuned to supply the rest by the guy standing over the hood. They get a few minutes of running if they don't mess with the engine too much or try to actually get it to do something.
Their variable fuel delivery system consumes less fuel than the engine would normally consume during the same few minutes of idling, and they wildly extrapolate it to 200mpg.
Or, they simply unplug their injectors and the engine apparently runs super efficient on their fuel can delivery system because the engine is hot and vapor is driving fuel out of the fuel rail. Manifold vacuum may be assisting. The super efficient running based on a different principle of energy transfer lasts as long as the fuel in the rail, leading them to conclude that an engine has to be properly designed to capture and utilize this different principle. It's the steady flow of fuel which normally keeps those components cool.
Whether it's those things or whether they need new valve guides, I doubt the experimenters have done more than nurse a few minutes of idling out of their super efficient engines because whatever means of accidental fuel delivery their engine is running on cannot respond to differing loads.
No. The motors utilizing fuel-detonation have been run long-term. You are correct though, that varying loads, or trying to operate the motor in different RPM bands -- and maintaining the high-efficiency -- can't be done. As I explained earlier on this thread, there is a "sweet spot" in operation, where timing the motion of the piston to the detonation impulse occurs, when you are out of that range you are stressing the motor components in a way similar to pre-ignition in conventional production internal-combustion motors and not operating with efficiency.
This "inflexibility" has been a significant factor (along with Keynesian ideas from economics driving business decisions) for why these motors haven't been put into production cars. With technology now allowing for economically produced "hybrid" gas-electric designs, I'm sure the engineering hurdles could be overcome easily. (The Keynesian thinking, and government-like bureaucracy within the major manufacturers' corporate structures, would still be a problem.)
quote:Originally posted by SoreShoulder
quote:Originally posted by competentoneNo. The motors utilizing fuel-detonation have been run long-term. Have you seen it and measured all the fluids going into the engine? I doubt it.
I'll believe it when I see it, if the oil is measured before and after and the fuel rail and injectors are drained or run dry first.
Besides, they probably measured how much fuel their engine uses per hour when idling normally, then got it to idle at the same RPM on vapors. However, they had to crack the throttle open more in order to let the vapors and air in because they take up more room than liquid gasoline and air. Pulling the air past the throttle is the main work which an idling engine is doing.
The gain just wouldn't transfer to a real world load unless the engine is far too large for the job.
I bet whenever they hit their sweet spot it is in an engine which is too large by far for the load which they find their sweet spot with. They don't understand that they are simply overcoming throttling losses by making the fuel take up more room. Hybrids are an answer as you have said, but there would be far more to gain by simply choosing an engine size that was not too large for the work and letting electric motors do the acceleration.
Do you really think everyone else is "just a bunch of idiots"?
Do you really think research on this has only been done by "backyard tinkerers"?
Do you really think this is something that was first developed when motors commonly had fuel injectors?
Or... As is the case with our VW TDI's we see over 50 mpg on a regular basis. Diesel fuel that is in a compression ignition engine.
Two factors at play. First is that diesel fuel carries more energy per measure than gasoline and second is that a diesel engine produces less waste heat than a gasoline fueled engine.
All the same the diesel engine is still far from being a paragon of efficiency. The same may be said for a hybrid or a totally electric vehicle as their energy is derived from fossil fuel in the main and the true numbers aren't really all that good when all is factored.
quote:Originally posted by nord
Or... As is the case with our VW TDI's we see over 50 mpg on a regular basis. Diesel fuel that is in a compression ignition engine.
Two factors at play. First is that diesel fuel carries more energy per measure than gasoline and second is that a diesel engine produces less waste heat than a gasoline fueled engine.
All the same the diesel engine is still far from being a paragon of efficiency. The same may be said for a hybrid or a totally electric vehicle as their energy is derived from fossil fuel in the main and the true numbers aren't really all that good when all is factored.
Would the diesel producing less heat, be why they will cool down when idling and my gas engine does not, at least not like a "black smoker" as we call them. [8D]
Just smile and say nothing, let them guess how much you know.
Exactly! Also the reason the VW TDI has an aux electric heater. Quicker defrost in the winter and quicker cabin comfort. Still it's a diesel and it takes longer to warm up. The electric heater just augments engine heat.
The OP was about obtaining 200 miles of travel from 1 gallon of gasoline. The "fancy engineering" shown is nothing but a red herring and some here have fallen for the bait.
So now the thread devolves into the minutia of the internal combustion engine and we seem to be discussing ways to make our engines more efficient. Might I remind you that the internal combustion engine is approaching a century and a quarter of practical development and that nothing discussed here hasn't been tried?
Somehow it appears that a few of us can't or won't accept the fact that our internal combustion engines are about 66% inefficient. Certainly we can tune them to be a bit better, or tune them for a particular application. And while we might squeeze out a few percentage points of efficiency over conventional engines, the fact remains that that majority of fuel used will go up in smoke and heat with no work being accomplished.
Is it so very hard to accept the simple fact that certain laws of physics cannot be altered? There exists a certain quantity of energy in a given measure of fuel. The only question needing answered is whether the amount of fuel in question contains enough energy to do the job at hand and also enough energy to cover the mechanical losses associated with the conversion of this fuel into actual work.
I respectfully submit that 1 gallon of gasoline contains not even enough energy to do the claimed job even at 100% efficiency let alone enough to cover mechanical losses. And unless some Einstein comes along and shows us how to obtain over 100% of the potential energy contained in fuel (Not going to happen.) then our discussion of technology and internal combustion efficiency is irrelevant.
Perhaps best to put it this way... Sniff enough gasoline fumes and one might well come to believe just about anything. All the same the vehicle in question will end up about 180 miles short of the claimed 200.
quote:Originally posted by SoreShoulder
quote:Originally posted by nord
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.
Because the 'amount' of energy in LP gas is nearly the same as the amount of energy, with the same unit of weight, contained in the hydrocarbon mixture we know as gasoline!!![;)]
I respectfully submit that 1 gallon of gasoline contains not even enough energy to do the claimed job even at 100% efficiency let alone enough to cover mechanical losses. And unless some Einstein comes along and shows us how to obtain over 100% of the potential energy contained in fuel (Not going to happen.) then our discussion of technology and internal combustion efficiency is irrelevant.
Perhaps best to put it this way... Sniff enough gasoline fumes and one might well come to believe just about anything. All the same the vehicle in question will end up about 180 miles short of the claimed 200.
The railroad industry (using turbine/diesel-electric) moves, on average, a ton of freight 436 miles using just one gallon of fuel. Why is the suggestion of an automobile going 70-80-90 miles (or more) on one gallon of fuel so inconceivable to you?
You're comparing apples and oranges. Railroads follow the flattest route possible, the nature of steel on steel makes for fairly low rolling friction, and railcars don't have a gasoline engine attached to every 4000 lbs. of weight with the associated transmissions, etc.
This combination makes for reasonably efficient use of fuel even considering that diesel locomotives convert fuel into mechanical energy, then mechanical energy into electrical energy, then back to mechanical energy via electric motors and associated mechanics. Every step produces heat and a loss, however size counts and the combination is fairly efficient in this application.
Our personal vehicles? Not even remotely a comparison.
But to the actual point. DOES THE AMOUNT OF FUEL IN QUESTION CONTAIN THE ENERGY POTENTIAL TO DO A PARTICULAR JOB? IS THERE ALSO ENOUGH ENERGY CONTENT TO COVER THE MECHANICAL LOSSES INVOLVED IN CONVERTING THIS ENERGY INTO REAL WORK AND COMPLETING THE JOB?
Bottom line is that it makes no difference what I think or what you think or believe. The only thing that matters is that the energy content of the fuel will cover all losses and the job at hand.
So... Does it, or doesn't it? Everything else is beside the point.
You're comparing apples and oranges. Railroads follow the flattest route possible, the nature of steel on steel makes for fairly low rolling friction, and railcars don't have a gasoline engine attached to every 4000 lbs. of weight with the associated transmissions, etc.
This combination makes for reasonably efficient use of fuel even considering that diesel locomotives convert fuel into mechanical energy, then mechanical energy into electrical energy, then back to mechanical energy via electric motors and associated mechanics. Every step produces heat and a loss, however size counts and the combination is fairly efficient in this application.
Our personal vehicles? Not even remotely a comparison.
But to the actual point. DOES THE AMOUNT OF FUEL IN QUESTION CONTAIN THE ENERGY POTENTIAL TO DO A PARTICULAR JOB? IS THERE ALSO ENOUGH ENERGY CONTENT TO COVER THE MECHANICAL LOSSES INVOLVED IN CONVERTING THIS ENERGY INTO REAL WORK AND COMPLETING THE JOB?
Bottom line is that it makes no difference what I think or what you think or believe. The only thing that matters is that the energy content of the fuel will cover all losses and the job at hand.
So... Does it, or doesn't it? Everything else is beside the point.
The energy content in one gallon of fuel is there to accomplish the work of moving the mass of an auto over the distance of 400+ miles -- that was my whole point in mentioning fuel used by the rail industry to do a certain amount of work.
I am well aware of the differences between autos and rail. Your insistence that "better fuel mileage isn't possible" is based on some adherence as immutable the "losses" you claim about the conversion of the energy in fuel to move physical masses.
My whole point in this discussion is that those losses are not immutable.
quote:Originally posted by SoreShoulder
Steel wheels on rails have a lot less rolling resistance.
The cars draft one another because they're in a row.
The load is not accelerating and decelerating nearly as much as a car.
The engines involved do not have nearly as much excess capacity as automotive engines leading to a reduction in cooling and friction losses.
Your "a lot less rolling resistance" is only 8%.
It is not "drafting" in rail-cars that explain their efficiency; it is their (relatively low) speed when compared to cruising speed in autos. (But I will give you credit for at lease recognizing wind resistance.)
Highway mileage and "city" mileage are different; the rail fuel consumption would be compared to "highway" figures for cars.
Cruising on flat surfaces (the way extreme fuel mileage can be observed best) normally requires less than 20 horsepower (mostly to overcome wind resistance). Any excess capacity built into the current motors for cars are not for cruising. (Refer back to my earlier comments about the limits of a motor built to operate on detonating fuel.)
"The energy content in one gallon of fuel is there to accomplish the work of moving the mass of an auto over the distance of 400+ miles -- that was my whole point in mentioning fuel used by the rail industry to do a certain amount of work."
Fine with me, but not just on your authority. Supply the figures backed by a reputable source. Give the details of all parasitic energy use and the total needs of the job versus the potential energy available in your gallon of gasoline.
Let me know when you come up at breakeven or better. I'm patient but I'm not all that ignorant. The energy simply isn't there given the parameters set forth in the OP.
And in direct reply to your statement... Even if the potential energy needed to move a vehicle as described in the OP exists in a gallon of gasoline and even if there's enough energy for 400 miles, we're still dealing with mechanical components which are about 30% efficient.
Unless my math is badly flawed your tank will be empty at the 133 mile mark. And in reality your fuel will be exhausted long before that in the real world.
They're overheating their pistons and valves since they're not being cooled with fuel so they're vaporizing their oil and drawing the vapor into the combustion chamber with the PCV valve.
They're overheating their regular fuel system since it's not being cooled by fresh fuel and it's causing fuel to dribble out of the jets or injectors,
Then they tweak their fuel vapor delivery system to keep the engine running at a constant speed, which also has the effect of adjusting for when the vapors and gas get inducted vs when they're not.
They are also probably comparing an idling normal engine with the same engine idling on vapor since a guy standing over the hood has to tweak the system to get it to run. That suggests they are opening the throttle more to let the vapor in. Drawing air past a nearly closed throttle is practically the only external work an idling engine is doing so its load is in effect cut to a small fraction of what it was when they were idling on the stock fuel system.
You (and nord) either do not understand, or are intentionally choosing to ignore what I'm talking about.
This isn't about "vapor" -- it is about utilizing the energy in a detonation of a fuel-air mixture. Do you understand the difference between detonation and deflagration (burning) from a physics perspective? Do you understand the power factor (pressure) jump as flame velocities approach and exceed the speed of sound in combustion (as compared to the heat release and pressures in burning)?
Do you really think the scientists and engineers who have worked on building motors transferring power to pistons (or impellers, vanes, or other solid components for the mechanical transfer of energy) by way of detonating fuel were "fooled" into thinking they had build a high-efficiency motor when all they really did was vaporize and burn lubricating oil?
(You really have an insulting attitude about other people's intelligence to suggest the sorts of things you are to try to "prove the impossibility" of a higher efficiency motor design.)
I guess it's my turn to be insulted... Somehow you seem to be reading into my posts things that simply aren't there. Or if they're there and I'm unaware, then please feel free to copy my exact words and correct my ineptitude.
I'm not aware that I've ever posted anything other than my doubts about claims made in the original post. I have no dog in the hunt regarding different methods of extracting energy from fuel. Truthfully I haven't a care whether you burn the fuel, explode it, sniff it, or drink it. It doesn't matter. All I've pointed out is that there are differing levels of inefficiency and that they must be accounted for when we convert any fuel into actual work.
But the point you seem to totally miss (ignore) is the one question needing answered... Does the quantity of fuel in question contain enough energy to accomplish a given task under given circumstances and also enough energy to account for the inefficiency of whatever method might be used to convert the potential energy of fuel into actual work?
The answer should be a simple yes or no. First we calculate the energy required to perform a given task. (In this case the movement of a particular vehicle weighing a certain number of pounds over a certain distance under certain conditions.) Then we calculate the efficiency at which we'll convert the potential energy in our fuel to actual work. Once we have both figures, we can then quite easily factor our total energy requirements. Educate me if I've missed something here. Why do you seem to avoid answering my question?
Now correct me if I'm wrong, but did anyone here see me attempting to argue about an engine or ignition type? I don't think I did. I merely mentioned that there are differences. But the fact remains that I don't give a care. Our engines all end up very close to the 30% efficiency mark. Some better and some poorer, but not by any great extent.
All I ever did was ask a simple question which has yet to be answered. Educate me here... Does the quantity and type of fuel on hand contain the energy to perform the work required and also enough extra energy to cover the mechanical and heat losses associated with this conversion?
So a simple question begging a simple answer I would think. Yes or no? It would seem that anyone as intelligent as you would easily be able to come forward with the facts and figures to prove your case. Read back through my posts and you'll find that I've never asked for more.
My personal opinion? The only way to move this 4000 lb. vehicle down the road at 200 mpg using a conventional reciprocating engine is to load it on a flatbed and allow it to idle for the entire trip. And even then I doubt a gallon of fuel will be enough to last the trip.
quote:Originally posted by nord
I guess it's my turn to be insulted... Somehow you seem to be reading into my posts things that simply aren't there. Or if they're there and I'm unaware, then please feel free to copy my exact words and correct my ineptitude.
I'm not aware that I've ever posted anything other than my doubts about claims made in the original post. I have no dog in the hunt regarding different methods of extracting energy from fuel. Truthfully I haven't a care whether you burn the fuel, explode it, sniff it, or drink it. It doesn't matter. All I've pointed out is that there are differing levels of inefficiency and that they must be accounted for when we convert any fuel into actual work.
But the point you seem to totally miss (ignore) is the one question needing answered... Does the quantity of fuel in question contain enough energy to accomplish a given task under given circumstances and also enough energy to account for the inefficiency of whatever method might be used to convert the potential energy of fuel into actual work?
The answer should be a simple yes or no. First we calculate the energy required to perform a given task. (In this case the movement of a particular vehicle weighing a certain number of pounds over a certain distance under certain conditions.) Then we calculate the efficiency at which we'll convert the potential energy in our fuel to actual work. Once we have both figures, we can then quite easily factor our total energy requirements. Educate me if I've missed something here. Why do you seem to avoid answering my question?
Now correct me if I'm wrong, but did anyone here see me attempting to argue about an engine or ignition type? I don't think I did. I merely mentioned that there are differences. But the fact remains that I don't give a care. Our engines all end up very close to the 30% efficiency mark. Some better and some poorer, but not by any great extent.
All I ever did was ask a simple question which has yet to be answered. Educate me here... Does the quantity and type of fuel on hand contain the energy to perform the work required and also enough extra energy to cover the mechanical and heat losses associated with this conversion?
So a simple question begging a simple answer I would think. Yes or no? It would seem that anyone as intelligent as you would easily be able to come forward with the facts and figures to prove your case. Read back through my posts and you'll find that I've never asked for more.
My personal opinion? The only way to move this 4000 lb. vehicle down the road at 200 mpg using a conventional reciprocating engine is to load it on a flatbed and allow it to idle for the entire trip. And even then I doubt a gallon of fuel will be enough to last the trip.
I see the problem with your thinking, you are not understanding the nature of machines. The machine itself changes the energy required to perform tasks.
Imagine you wanted to move a block of rock across a quarry. You carefully calculate the coefficient of friction for dragging that rock across the surface and come up with your calculation for the "energy needed." You treat as immutable a variable in your equation that isn't. I use a simple machine -- an axle and wheel -- set that rock on a cart and accomplish the task using a fraction of the energy you had calculated was needed.
("SoreShoulder" then comes over and starts arguing that I haven't really saved energy because I forgot to include the energy needed for lifting that rock onto the cart.)
I'll anticipate your response to my example: You'll now say, but: there is a certain amount of energy needed for dragging the rock, and there is a certain amount of energy needed for rolling the rock on a cart -- and each of those represents "a task" requiring a set amount of energy. This is closer to the differences in our positions: You are calculating the rolling resistance for a cart using a crude wooden axle and wheel; I'm saying the machine (wheel and axle) can be built to operate much more efficiently, so your "energy needed" calculation is wrong.
The variable of friction in a crude axle vs. a well-designed one is a relatively minor difference compared to the variables one can manipulate in a more complex machine, such as in combustion motors. (I'll just add that comment in anticipation of any argument that extreme gains in fuel efficiency I'm suggesting is possible with different motor designs isn't an accurate comparison to my axle/wheel analogy.)
My biggest disagreement with you is your position: "Our engines all end up very close to the 30% efficiency mark. Some better and some poorer, but not by any great extent." I'd go even farther and could question how you (generic "you") have arrived at even that "30%" efficiency number, but since "you don't care" (and I don't either, since I'm not being paid here) I don't see any need to extend the discussion in that direction.
And I, too, agree. Not only is the continuation of this discussion at a point where it should be terminated, I believe we also agree on the basics but are looking at the problem at hand from two entirely different perspectives.
You would define the job and attempt to figure out the most efficient method of getting a job done using the least amount of energy. This is the smart way of doing things. Unfortunately in this particular thread the job had already been defined. Nothing you or I can do to change the fact.
So my question remains valid no matter how easy or hard the job placed before us... Do we have enough potential energy available to do a particular job and enough extra to account for parasitic losses?
As to engine efficiency please refer to the report below and remember that we're only considering the engine here and not the balance of the mechanical components required to get power to the ground. I believe you'll find my quote of about 30% efficiency to be very close to correct.
Most internal combustion engines are incredibly inefficient at turning fuel burned into usable energy.
The efficiency by which they do so is measured in terms of "thermal efficiency", and most gasoline combustion engines average around 20 percent thermal efficiency. Diesels are typically higher--approaching 40 percent in some cases.
Toyota has now developed a new gasoline engine which it claims has a maximum thermal efficiency of 38 percent--greater than any other mass-produced combustion engine.
The new units, 1.0 and 1.3-liters in capacity, should enable 10-15 percent greater economy than their existing equivalents.
Toyota has applied several familiar technologies to its engines to achieve these levels of efficiency.
One of these is the same combustion cycle used in the firm's hybrid models--the Atkinson cycle.
Used on the 1.3-liter unit, Atkinson-cycle engines typically feature variable valve timing, allowing inlet valves to remain open as the compression stroke begins. The lower air density leads to a more efficient fuel burn and higher thermal efficiency.
Typically, the engines lack power compared to conventional Otto-cycle engines--offset in hybrids by additional power from the electric motor.
MORE: 2015 Toyota Prius: Next Hybrid Aims For 55 MPG, More Room, Better Handling
In the 1.3-liter engine, a 13.5 compression ratio makes up for some of the lost compression through the engine's cycle--in theory, the engine should perform similarly to a regular 1.3-liter unit.
Redesigned intake ports, variable valve timing and cooled exhaust gas recirculation are also employed to improve the engine's efficiency.
On the 1.0-liter unit, co-developed with Toyota's Japanese partner Daihatsu, similar engine technologies (without the Atkinson cycle, this time) contribute to 37 percent thermal efficiency.
Through the use of stop-start technology though, the new engine is 30 percent more efficient than equivalent 1.0-liter units on the city-biased Japanese JC08 test cycle.
Toyota hasn't confirmed which vehicles the new engines will be used in, nor whether either powerplant will come to the U.S. It's likely several Japanese-market vehicles and selected models like the Yaris and Aygo sold overseas will eventually benefit from the units.
What it does show is that there's still plenty of room for improvement in conventional gasoline engines.
Regular internal combustion engines will remain dominant in road transportation for the next few decades at least--so any effort to improve them in the meantime should be applauded.
Comments
The fellow in the video seemed to have a means of tuning his fuel delivery.
In certain situations these experimenters may have gotten a few minutes of apparently very efficient running if they didn't mess with the engine too much.
They may have failed to realize that the fuel in a normal engine does vaporize and in so doing, it cools the piston and combustion chamber.
They may actually be vaporizing their crankcase oil and fueling their engine with it through the PCV valve.
Gaseous fuel makes an engine run hotter!
Then, the gasoline vaporizer system is tuned to supply the rest by the guy standing over the hood. They get a few minutes of running if they don't mess with the engine too much or try to actually get it to do something.
Their variable fuel delivery system consumes less fuel than the engine would normally consume during the same few minutes of idling, and they wildly extrapolate it to 200mpg.
Or, they simply unplug their injectors and the engine apparently runs super efficient on their fuel can delivery system because the engine is hot and vapor is driving fuel out of the fuel rail. Manifold vacuum may be assisting. The super efficient running based on a different principle of energy transfer lasts as long as the fuel in the rail, leading them to conclude that an engine has to be properly designed to capture and utilize this different principle. It's the steady flow of fuel which normally keeps those components cool.
Whether it's those things or whether they need new valve guides, I doubt the experimenters have done more than nurse a few minutes of idling out of their super efficient engines because whatever means of accidental fuel delivery their engine is running on cannot respond to differing loads.
No. The motors utilizing fuel-detonation have been run long-term. You are correct though, that varying loads, or trying to operate the motor in different RPM bands -- and maintaining the high-efficiency -- can't be done. As I explained earlier on this thread, there is a "sweet spot" in operation, where timing the motion of the piston to the detonation impulse occurs, when you are out of that range you are stressing the motor components in a way similar to pre-ignition in conventional production internal-combustion motors and not operating with efficiency.
This "inflexibility" has been a significant factor (along with Keynesian ideas from economics driving business decisions) for why these motors haven't been put into production cars. With technology now allowing for economically produced "hybrid" gas-electric designs, I'm sure the engineering hurdles could be overcome easily. (The Keynesian thinking, and government-like bureaucracy within the major manufacturers' corporate structures, would still be a problem.)
quote:Originally posted by competentoneNo. The motors utilizing fuel-detonation have been run long-term. Have you seen it and measured all the fluids going into the engine? I doubt it.
I'll believe it when I see it, if the oil is measured before and after and the fuel rail and injectors are drained or run dry first.
Besides, they probably measured how much fuel their engine uses per hour when idling normally, then got it to idle at the same RPM on vapors. However, they had to crack the throttle open more in order to let the vapors and air in because they take up more room than liquid gasoline and air. Pulling the air past the throttle is the main work which an idling engine is doing.
The gain just wouldn't transfer to a real world load unless the engine is far too large for the job.
I bet whenever they hit their sweet spot it is in an engine which is too large by far for the load which they find their sweet spot with. They don't understand that they are simply overcoming throttling losses by making the fuel take up more room. Hybrids are an answer as you have said, but there would be far more to gain by simply choosing an engine size that was not too large for the work and letting electric motors do the acceleration.
Do you really think everyone else is "just a bunch of idiots"?
Do you really think research on this has only been done by "backyard tinkerers"?
Do you really think this is something that was first developed when motors commonly had fuel injectors?
Two factors at play. First is that diesel fuel carries more energy per measure than gasoline and second is that a diesel engine produces less waste heat than a gasoline fueled engine.
All the same the diesel engine is still far from being a paragon of efficiency. The same may be said for a hybrid or a totally electric vehicle as their energy is derived from fossil fuel in the main and the true numbers aren't really all that good when all is factored.
Or... As is the case with our VW TDI's we see over 50 mpg on a regular basis. Diesel fuel that is in a compression ignition engine.
Two factors at play. First is that diesel fuel carries more energy per measure than gasoline and second is that a diesel engine produces less waste heat than a gasoline fueled engine.
All the same the diesel engine is still far from being a paragon of efficiency. The same may be said for a hybrid or a totally electric vehicle as their energy is derived from fossil fuel in the main and the true numbers aren't really all that good when all is factored.
Would the diesel producing less heat, be why they will cool down when idling and my gas engine does not, at least not like a "black smoker" as we call them. [8D]
The OP was about obtaining 200 miles of travel from 1 gallon of gasoline. The "fancy engineering" shown is nothing but a red herring and some here have fallen for the bait.
So now the thread devolves into the minutia of the internal combustion engine and we seem to be discussing ways to make our engines more efficient. Might I remind you that the internal combustion engine is approaching a century and a quarter of practical development and that nothing discussed here hasn't been tried?
Somehow it appears that a few of us can't or won't accept the fact that our internal combustion engines are about 66% inefficient. Certainly we can tune them to be a bit better, or tune them for a particular application. And while we might squeeze out a few percentage points of efficiency over conventional engines, the fact remains that that majority of fuel used will go up in smoke and heat with no work being accomplished.
Is it so very hard to accept the simple fact that certain laws of physics cannot be altered? There exists a certain quantity of energy in a given measure of fuel. The only question needing answered is whether the amount of fuel in question contains enough energy to do the job at hand and also enough energy to cover the mechanical losses associated with the conversion of this fuel into actual work.
I respectfully submit that 1 gallon of gasoline contains not even enough energy to do the claimed job even at 100% efficiency let alone enough to cover mechanical losses. And unless some Einstein comes along and shows us how to obtain over 100% of the potential energy contained in fuel (Not going to happen.) then our discussion of technology and internal combustion efficiency is irrelevant.
Perhaps best to put it this way... Sniff enough gasoline fumes and one might well come to believe just about anything. All the same the vehicle in question will end up about 180 miles short of the claimed 200.
quote:Originally posted by nord
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.
Because the 'amount' of energy in LP gas is nearly the same as the amount of energy, with the same unit of weight, contained in the hydrocarbon mixture we know as gasoline!!![;)]
I respectfully submit that 1 gallon of gasoline contains not even enough energy to do the claimed job even at 100% efficiency let alone enough to cover mechanical losses. And unless some Einstein comes along and shows us how to obtain over 100% of the potential energy contained in fuel (Not going to happen.) then our discussion of technology and internal combustion efficiency is irrelevant.
Perhaps best to put it this way... Sniff enough gasoline fumes and one might well come to believe just about anything. All the same the vehicle in question will end up about 180 miles short of the claimed 200.
The railroad industry (using turbine/diesel-electric) moves, on average, a ton of freight 436 miles using just one gallon of fuel. Why is the suggestion of an automobile going 70-80-90 miles (or more) on one gallon of fuel so inconceivable to you?
You're comparing apples and oranges. Railroads follow the flattest route possible, the nature of steel on steel makes for fairly low rolling friction, and railcars don't have a gasoline engine attached to every 4000 lbs. of weight with the associated transmissions, etc.
This combination makes for reasonably efficient use of fuel even considering that diesel locomotives convert fuel into mechanical energy, then mechanical energy into electrical energy, then back to mechanical energy via electric motors and associated mechanics. Every step produces heat and a loss, however size counts and the combination is fairly efficient in this application.
Our personal vehicles? Not even remotely a comparison.
But to the actual point. DOES THE AMOUNT OF FUEL IN QUESTION CONTAIN THE ENERGY POTENTIAL TO DO A PARTICULAR JOB? IS THERE ALSO ENOUGH ENERGY CONTENT TO COVER THE MECHANICAL LOSSES INVOLVED IN CONVERTING THIS ENERGY INTO REAL WORK AND COMPLETING THE JOB?
Bottom line is that it makes no difference what I think or what you think or believe. The only thing that matters is that the energy content of the fuel will cover all losses and the job at hand.
So... Does it, or doesn't it? Everything else is beside the point.
Once more...
You're comparing apples and oranges. Railroads follow the flattest route possible, the nature of steel on steel makes for fairly low rolling friction, and railcars don't have a gasoline engine attached to every 4000 lbs. of weight with the associated transmissions, etc.
This combination makes for reasonably efficient use of fuel even considering that diesel locomotives convert fuel into mechanical energy, then mechanical energy into electrical energy, then back to mechanical energy via electric motors and associated mechanics. Every step produces heat and a loss, however size counts and the combination is fairly efficient in this application.
Our personal vehicles? Not even remotely a comparison.
But to the actual point. DOES THE AMOUNT OF FUEL IN QUESTION CONTAIN THE ENERGY POTENTIAL TO DO A PARTICULAR JOB? IS THERE ALSO ENOUGH ENERGY CONTENT TO COVER THE MECHANICAL LOSSES INVOLVED IN CONVERTING THIS ENERGY INTO REAL WORK AND COMPLETING THE JOB?
Bottom line is that it makes no difference what I think or what you think or believe. The only thing that matters is that the energy content of the fuel will cover all losses and the job at hand.
So... Does it, or doesn't it? Everything else is beside the point.
The energy content in one gallon of fuel is there to accomplish the work of moving the mass of an auto over the distance of 400+ miles -- that was my whole point in mentioning fuel used by the rail industry to do a certain amount of work.
I am well aware of the differences between autos and rail. Your insistence that "better fuel mileage isn't possible" is based on some adherence as immutable the "losses" you claim about the conversion of the energy in fuel to move physical masses.
My whole point in this discussion is that those losses are not immutable.
Steel wheels on rails have a lot less rolling resistance.
The cars draft one another because they're in a row.
The load is not accelerating and decelerating nearly as much as a car.
The engines involved do not have nearly as much excess capacity as automotive engines leading to a reduction in cooling and friction losses.
Your "a lot less rolling resistance" is only 8%.
It is not "drafting" in rail-cars that explain their efficiency; it is their (relatively low) speed when compared to cruising speed in autos. (But I will give you credit for at lease recognizing wind resistance.)
Highway mileage and "city" mileage are different; the rail fuel consumption would be compared to "highway" figures for cars.
Cruising on flat surfaces (the way extreme fuel mileage can be observed best) normally requires less than 20 horsepower (mostly to overcome wind resistance). Any excess capacity built into the current motors for cars are not for cruising. (Refer back to my earlier comments about the limits of a motor built to operate on detonating fuel.)
Fine with me, but not just on your authority. Supply the figures backed by a reputable source. Give the details of all parasitic energy use and the total needs of the job versus the potential energy available in your gallon of gasoline.
Let me know when you come up at breakeven or better. I'm patient but I'm not all that ignorant. The energy simply isn't there given the parameters set forth in the OP.
And in direct reply to your statement... Even if the potential energy needed to move a vehicle as described in the OP exists in a gallon of gasoline and even if there's enough energy for 400 miles, we're still dealing with mechanical components which are about 30% efficient.
Unless my math is badly flawed your tank will be empty at the 133 mile mark. And in reality your fuel will be exhausted long before that in the real world.
They're overheating their pistons and valves since they're not being cooled with fuel so they're vaporizing their oil and drawing the vapor into the combustion chamber with the PCV valve.
They're overheating their regular fuel system since it's not being cooled by fresh fuel and it's causing fuel to dribble out of the jets or injectors,
Then they tweak their fuel vapor delivery system to keep the engine running at a constant speed, which also has the effect of adjusting for when the vapors and gas get inducted vs when they're not.
They are also probably comparing an idling normal engine with the same engine idling on vapor since a guy standing over the hood has to tweak the system to get it to run. That suggests they are opening the throttle more to let the vapor in. Drawing air past a nearly closed throttle is practically the only external work an idling engine is doing so its load is in effect cut to a small fraction of what it was when they were idling on the stock fuel system.
You (and nord) either do not understand, or are intentionally choosing to ignore what I'm talking about.
This isn't about "vapor" -- it is about utilizing the energy in a detonation of a fuel-air mixture. Do you understand the difference between detonation and deflagration (burning) from a physics perspective? Do you understand the power factor (pressure) jump as flame velocities approach and exceed the speed of sound in combustion (as compared to the heat release and pressures in burning)?
Do you really think the scientists and engineers who have worked on building motors transferring power to pistons (or impellers, vanes, or other solid components for the mechanical transfer of energy) by way of detonating fuel were "fooled" into thinking they had build a high-efficiency motor when all they really did was vaporize and burn lubricating oil?
(You really have an insulting attitude about other people's intelligence to suggest the sorts of things you are to try to "prove the impossibility" of a higher efficiency motor design.)
I'm not aware that I've ever posted anything other than my doubts about claims made in the original post. I have no dog in the hunt regarding different methods of extracting energy from fuel. Truthfully I haven't a care whether you burn the fuel, explode it, sniff it, or drink it. It doesn't matter. All I've pointed out is that there are differing levels of inefficiency and that they must be accounted for when we convert any fuel into actual work.
But the point you seem to totally miss (ignore) is the one question needing answered... Does the quantity of fuel in question contain enough energy to accomplish a given task under given circumstances and also enough energy to account for the inefficiency of whatever method might be used to convert the potential energy of fuel into actual work?
The answer should be a simple yes or no. First we calculate the energy required to perform a given task. (In this case the movement of a particular vehicle weighing a certain number of pounds over a certain distance under certain conditions.) Then we calculate the efficiency at which we'll convert the potential energy in our fuel to actual work. Once we have both figures, we can then quite easily factor our total energy requirements. Educate me if I've missed something here. Why do you seem to avoid answering my question?
Now correct me if I'm wrong, but did anyone here see me attempting to argue about an engine or ignition type? I don't think I did. I merely mentioned that there are differences. But the fact remains that I don't give a care. Our engines all end up very close to the 30% efficiency mark. Some better and some poorer, but not by any great extent.
All I ever did was ask a simple question which has yet to be answered. Educate me here... Does the quantity and type of fuel on hand contain the energy to perform the work required and also enough extra energy to cover the mechanical and heat losses associated with this conversion?
So a simple question begging a simple answer I would think. Yes or no? It would seem that anyone as intelligent as you would easily be able to come forward with the facts and figures to prove your case. Read back through my posts and you'll find that I've never asked for more.
My personal opinion? The only way to move this 4000 lb. vehicle down the road at 200 mpg using a conventional reciprocating engine is to load it on a flatbed and allow it to idle for the entire trip. And even then I doubt a gallon of fuel will be enough to last the trip.
I guess it's my turn to be insulted... Somehow you seem to be reading into my posts things that simply aren't there. Or if they're there and I'm unaware, then please feel free to copy my exact words and correct my ineptitude.
I'm not aware that I've ever posted anything other than my doubts about claims made in the original post. I have no dog in the hunt regarding different methods of extracting energy from fuel. Truthfully I haven't a care whether you burn the fuel, explode it, sniff it, or drink it. It doesn't matter. All I've pointed out is that there are differing levels of inefficiency and that they must be accounted for when we convert any fuel into actual work.
But the point you seem to totally miss (ignore) is the one question needing answered... Does the quantity of fuel in question contain enough energy to accomplish a given task under given circumstances and also enough energy to account for the inefficiency of whatever method might be used to convert the potential energy of fuel into actual work?
The answer should be a simple yes or no. First we calculate the energy required to perform a given task. (In this case the movement of a particular vehicle weighing a certain number of pounds over a certain distance under certain conditions.) Then we calculate the efficiency at which we'll convert the potential energy in our fuel to actual work. Once we have both figures, we can then quite easily factor our total energy requirements. Educate me if I've missed something here. Why do you seem to avoid answering my question?
Now correct me if I'm wrong, but did anyone here see me attempting to argue about an engine or ignition type? I don't think I did. I merely mentioned that there are differences. But the fact remains that I don't give a care. Our engines all end up very close to the 30% efficiency mark. Some better and some poorer, but not by any great extent.
All I ever did was ask a simple question which has yet to be answered. Educate me here... Does the quantity and type of fuel on hand contain the energy to perform the work required and also enough extra energy to cover the mechanical and heat losses associated with this conversion?
So a simple question begging a simple answer I would think. Yes or no? It would seem that anyone as intelligent as you would easily be able to come forward with the facts and figures to prove your case. Read back through my posts and you'll find that I've never asked for more.
My personal opinion? The only way to move this 4000 lb. vehicle down the road at 200 mpg using a conventional reciprocating engine is to load it on a flatbed and allow it to idle for the entire trip. And even then I doubt a gallon of fuel will be enough to last the trip.
I see the problem with your thinking, you are not understanding the nature of machines. The machine itself changes the energy required to perform tasks.
Imagine you wanted to move a block of rock across a quarry. You carefully calculate the coefficient of friction for dragging that rock across the surface and come up with your calculation for the "energy needed." You treat as immutable a variable in your equation that isn't. I use a simple machine -- an axle and wheel -- set that rock on a cart and accomplish the task using a fraction of the energy you had calculated was needed.
("SoreShoulder" then comes over and starts arguing that I haven't really saved energy because I forgot to include the energy needed for lifting that rock onto the cart.)
I'll anticipate your response to my example: You'll now say, but: there is a certain amount of energy needed for dragging the rock, and there is a certain amount of energy needed for rolling the rock on a cart -- and each of those represents "a task" requiring a set amount of energy. This is closer to the differences in our positions: You are calculating the rolling resistance for a cart using a crude wooden axle and wheel; I'm saying the machine (wheel and axle) can be built to operate much more efficiently, so your "energy needed" calculation is wrong.
The variable of friction in a crude axle vs. a well-designed one is a relatively minor difference compared to the variables one can manipulate in a more complex machine, such as in combustion motors. (I'll just add that comment in anticipation of any argument that extreme gains in fuel efficiency I'm suggesting is possible with different motor designs isn't an accurate comparison to my axle/wheel analogy.)
My biggest disagreement with you is your position: "Our engines all end up very close to the 30% efficiency mark. Some better and some poorer, but not by any great extent." I'd go even farther and could question how you (generic "you") have arrived at even that "30%" efficiency number, but since "you don't care" (and I don't either, since I'm not being paid here) I don't see any need to extend the discussion in that direction.
You would define the job and attempt to figure out the most efficient method of getting a job done using the least amount of energy. This is the smart way of doing things. Unfortunately in this particular thread the job had already been defined. Nothing you or I can do to change the fact.
So my question remains valid no matter how easy or hard the job placed before us... Do we have enough potential energy available to do a particular job and enough extra to account for parasitic losses?
As to engine efficiency please refer to the report below and remember that we're only considering the engine here and not the balance of the mechanical components required to get power to the ground. I believe you'll find my quote of about 30% efficiency to be very close to correct.
From GREEN CAR REPORTS:
By Antony Ingram Antony Ingram
143 Comments 6,290 views Apr 14, 2014
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Toyota 1.3-liter Atkinson-cycle gasoline engine
Toyota 1.3-liter Atkinson-cycle gasoline engine
Most internal combustion engines are incredibly inefficient at turning fuel burned into usable energy.
The efficiency by which they do so is measured in terms of "thermal efficiency", and most gasoline combustion engines average around 20 percent thermal efficiency. Diesels are typically higher--approaching 40 percent in some cases.
Toyota has now developed a new gasoline engine which it claims has a maximum thermal efficiency of 38 percent--greater than any other mass-produced combustion engine.
The new units, 1.0 and 1.3-liters in capacity, should enable 10-15 percent greater economy than their existing equivalents.
Toyota has applied several familiar technologies to its engines to achieve these levels of efficiency.
One of these is the same combustion cycle used in the firm's hybrid models--the Atkinson cycle.
Used on the 1.3-liter unit, Atkinson-cycle engines typically feature variable valve timing, allowing inlet valves to remain open as the compression stroke begins. The lower air density leads to a more efficient fuel burn and higher thermal efficiency.
Typically, the engines lack power compared to conventional Otto-cycle engines--offset in hybrids by additional power from the electric motor.
MORE: 2015 Toyota Prius: Next Hybrid Aims For 55 MPG, More Room, Better Handling
In the 1.3-liter engine, a 13.5 compression ratio makes up for some of the lost compression through the engine's cycle--in theory, the engine should perform similarly to a regular 1.3-liter unit.
Redesigned intake ports, variable valve timing and cooled exhaust gas recirculation are also employed to improve the engine's efficiency.
On the 1.0-liter unit, co-developed with Toyota's Japanese partner Daihatsu, similar engine technologies (without the Atkinson cycle, this time) contribute to 37 percent thermal efficiency.
Through the use of stop-start technology though, the new engine is 30 percent more efficient than equivalent 1.0-liter units on the city-biased Japanese JC08 test cycle.
Toyota hasn't confirmed which vehicles the new engines will be used in, nor whether either powerplant will come to the U.S. It's likely several Japanese-market vehicles and selected models like the Yaris and Aygo sold overseas will eventually benefit from the units.
What it does show is that there's still plenty of room for improvement in conventional gasoline engines.
Regular internal combustion engines will remain dominant in road transportation for the next few decades at least--so any effort to improve them in the meantime should be applauded.