100 Miles Per Gallon
- Thread starter Barry Rietz
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That's an interesting engine and I love new engine designs. So what follows is just a discussion and I hope it proves out.
According to one of my favorite books, the opposed engine was successfully used by Gobron-Brillie (a French manufacturer) as early as 1890. The book, Veteran and Edwardian Motor Cars, by David Scott Moncrieff, describes the motor as shown in the YouTube and claims it was offered in various sizes up to 6 cylinders until 1929. In 1902, the car won it's class in the Paris-Vienna Grand Prix. So it's a proven design.
Also, the Gray Marine engine of 1939 (which later became the beloved GMC 6-71 series,) was a diesel 2 stroke, scavenged by a supercharger. The 71 series used a positive Roots type blower since there was no crankcase compression as on conventional 2-strokes. I believe that's the reason for the electric motor driven turbocharger on the the proposed engine, to get it started and at low engine speeds.
So the new engine uses several well tested principals, and we'll have to see how it works.
Basically all combustion engines change thermal energy into work at some efficiency. I missed that part of the discussion. For reference, the steam engine is about 25% efficient and the diesel is 40%, which is why we don't see steam engines anymore. I don't see why that new engine would be more thermally efficient than a "normal" gas or diesel turbocharged engine, unless it reduced the amount of heat rejected to the atmosphere via cooling or exhaust gas temperature. Efficiency= Work/Energy Supplied. So there has to be some improvement in the thermal efficiency which is not discussed in that short video.
Anyway, Good Luck
Boris
According to one of my favorite books, the opposed engine was successfully used by Gobron-Brillie (a French manufacturer) as early as 1890. The book, Veteran and Edwardian Motor Cars, by David Scott Moncrieff, describes the motor as shown in the YouTube and claims it was offered in various sizes up to 6 cylinders until 1929. In 1902, the car won it's class in the Paris-Vienna Grand Prix. So it's a proven design.
Also, the Gray Marine engine of 1939 (which later became the beloved GMC 6-71 series,) was a diesel 2 stroke, scavenged by a supercharger. The 71 series used a positive Roots type blower since there was no crankcase compression as on conventional 2-strokes. I believe that's the reason for the electric motor driven turbocharger on the the proposed engine, to get it started and at low engine speeds.
So the new engine uses several well tested principals, and we'll have to see how it works.
Basically all combustion engines change thermal energy into work at some efficiency. I missed that part of the discussion. For reference, the steam engine is about 25% efficient and the diesel is 40%, which is why we don't see steam engines anymore. I don't see why that new engine would be more thermally efficient than a "normal" gas or diesel turbocharged engine, unless it reduced the amount of heat rejected to the atmosphere via cooling or exhaust gas temperature. Efficiency= Work/Energy Supplied. So there has to be some improvement in the thermal efficiency which is not discussed in that short video.
Anyway, Good Luck
Boris
MilesandMiles
New member
I've visited this fella several times.
http://home.myfairpoint.net/vze6omtd/jo ... index.html
The best I've ever pulled from a Geo Metro is 67mpg A few others have seen 70-82mpg highly mod'ed
http://home.myfairpoint.net/vze6omtd/jo ... index.html
The best I've ever pulled from a Geo Metro is 67mpg A few others have seen 70-82mpg highly mod'ed
journey on
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Now, I understand that car. To go a 100 miles, it does less work, and thus requires less thermal energy input. Even with a thermal efficiency of 30% (normal for a small IC gas engine.)
Remember, work=force*distance moved. So the less force you exert to move something, the less work. Given the light weight and small cross section, the force is certainly less than my 3/4 ton truck, and using a gas engine with normal thermal efficiency, you don't need to burn much gasoline.
Just to show how efficient our outboards are, here's a post from the "traveling at Trawler Speed" topic, which I've edited:
At 21 knts, he's burning 5 gph, which is ~600,000 btu/hr or an average of 225 HP over that hour. Since the max HP is 100 (2 ea. 50's) let's assume that he's using 75 HP. Then the thermal efficiency is somewhere less than 33%. Which is in line with that mini-car above. That's HP the engine is putting out, it doesn't include prop efficiency, I assume. So we're lucky if we get 25% of the energy in a gallon of gasoline.
Boris
Remember, work=force*distance moved. So the less force you exert to move something, the less work. Given the light weight and small cross section, the force is certainly less than my 3/4 ton truck, and using a gas engine with normal thermal efficiency, you don't need to burn much gasoline.
Just to show how efficient our outboards are, here's a post from the "traveling at Trawler Speed" topic, which I've edited:
jmcintyre":2mlj9her said:
At 21 knts, he's burning 5 gph, which is ~600,000 btu/hr or an average of 225 HP over that hour. Since the max HP is 100 (2 ea. 50's) let's assume that he's using 75 HP. Then the thermal efficiency is somewhere less than 33%. Which is in line with that mini-car above. That's HP the engine is putting out, it doesn't include prop efficiency, I assume. So we're lucky if we get 25% of the energy in a gallon of gasoline.
Boris
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The point that I've been trying to make is this:
Instead of inventing mechanical devices that use less energy (smaller cars, for example, are good) what we really could use are devices that operate at greater thermal efficiency. Note that I don't have a solution.
The internal combustion engine hasn't seen a radical advance since Rudolph Diesel invented the compression engine. Certainly, for the gasoline engine, higher compression ratios, turbochargers, etc. have increased thermal efficiency, but we could use an entirely new concept. Improving the amount of air an engine can pump doesn't count, since it just allows a smaller engine to produce more HP, no change in thermal efficiency.
As for the electric car, that just shifts the energy requirement from gasoline to coal and natural gas. And how efficient are those big electric generators? according to a National Petroleum Council report, 33% avg; 38% for the natural gas plants. So by the time the power is sent to your house and converted to work by an electric motor (car, fan, refridge, etc.) the end-to-end efficiency is about 30%. Electric cars & outboard motors aren't efficient, they just ship the power requirements elsewhere. For the car, it does regain some of its kinetic energy via regenerative braking, but that doesn't do much for a trip between LA and SF. And doesn't do anything for trucks.
And now I'll let this topic go.
Boris
Instead of inventing mechanical devices that use less energy (smaller cars, for example, are good) what we really could use are devices that operate at greater thermal efficiency. Note that I don't have a solution.
The internal combustion engine hasn't seen a radical advance since Rudolph Diesel invented the compression engine. Certainly, for the gasoline engine, higher compression ratios, turbochargers, etc. have increased thermal efficiency, but we could use an entirely new concept. Improving the amount of air an engine can pump doesn't count, since it just allows a smaller engine to produce more HP, no change in thermal efficiency.
As for the electric car, that just shifts the energy requirement from gasoline to coal and natural gas. And how efficient are those big electric generators? according to a National Petroleum Council report, 33% avg; 38% for the natural gas plants. So by the time the power is sent to your house and converted to work by an electric motor (car, fan, refridge, etc.) the end-to-end efficiency is about 30%. Electric cars & outboard motors aren't efficient, they just ship the power requirements elsewhere. For the car, it does regain some of its kinetic energy via regenerative braking, but that doesn't do much for a trip between LA and SF. And doesn't do anything for trucks.
And now I'll let this topic go.
Boris
Boris - don't let it go. Interesting stuff and well presented. I had never heard of Rudolph Diesel. It's amazing that he has the same name as the fuel used in his engine.
How efficient is a nuclear sub? (No, no, no. I am not going to suggest a nuclear outboard!) Those have steam engines running generators, correct? Is their steam turbine better than 25% efficient or is just the best use of the heat produced by the fuel?
How efficient is a nuclear sub? (No, no, no. I am not going to suggest a nuclear outboard!) Those have steam engines running generators, correct? Is their steam turbine better than 25% efficient or is just the best use of the heat produced by the fuel?
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Good heavens, TyBoo, you don't know what you've unleashed on this topic.
First, I believe that the fuel was named after good old Rudolf Diesel. I'm not sure, but when I visited the Smithsonian Natural History Museum, they had a VERY early Diesel engine that used coal. So it'll burn just about any flammable substance. And, by the way, those big diesel engines on ships are claimed to have 50% efficiency, not counting propeller losses. If you remember Buda Diesel motors, they still build the big ones in Wisconsin (if there still is a Wisconsin.)
Second, for a nuclear sub, it depends how one calculates efficiency. If it's just how the heat is used, it's the same as any other steam turbine. My text book, circa 1955, says max steam turbine efficiency is ~80%. If you want to calculate the heat losses from the reactor thru the boiler to the turbine, I'd guess another 10% loss. Electric motor efficiency should be ~90%. Propeller efficiency? The ones I know range from 40% to 70% efficient. But I never designed nuclear subs. So, from reactor heat in to propeller output, let's try ~50% and maximum load, whatever that is.
That would compare with 20% for a C-Dory, gasoline in to propeller out.
Boris
First, I believe that the fuel was named after good old Rudolf Diesel. I'm not sure, but when I visited the Smithsonian Natural History Museum, they had a VERY early Diesel engine that used coal. So it'll burn just about any flammable substance. And, by the way, those big diesel engines on ships are claimed to have 50% efficiency, not counting propeller losses. If you remember Buda Diesel motors, they still build the big ones in Wisconsin (if there still is a Wisconsin.)
Second, for a nuclear sub, it depends how one calculates efficiency. If it's just how the heat is used, it's the same as any other steam turbine. My text book, circa 1955, says max steam turbine efficiency is ~80%. If you want to calculate the heat losses from the reactor thru the boiler to the turbine, I'd guess another 10% loss. Electric motor efficiency should be ~90%. Propeller efficiency? The ones I know range from 40% to 70% efficient. But I never designed nuclear subs. So, from reactor heat in to propeller output, let's try ~50% and maximum load, whatever that is.
That would compare with 20% for a C-Dory, gasoline in to propeller out.
Boris
All very interesting!
While there might not be any major break-throughs efficiency in sight, I could do 90% of my driving around Redding in a reasonably efficient electric car.
Once the money was invested to get the car, an array solar electric panels, transformers, and controlling equipment could recharge it, except in the middle of winter, etc.
Excess power development could be run into my home and on into the grid system for credit and retrieval later.
The big hang-up would be the up-front cost of the solar-electric generation system, which would pretty much be a deal-beaker, unless one could get a special low-interest loan and/or a tax break too.
The whole system should be incorporated into a complete solar-electric system for one's home, as is already commonly done. While certainly not cheap at all, it would get us away from so much dependence on gas if practiced on a wide-scale basis.
Yes, I'm aware that domestic solar-electric only a relatively small part of our total energy consumption, but we have to start somewhere.
Joe. :teeth :thup
While there might not be any major break-throughs efficiency in sight, I could do 90% of my driving around Redding in a reasonably efficient electric car.
Once the money was invested to get the car, an array solar electric panels, transformers, and controlling equipment could recharge it, except in the middle of winter, etc.
Excess power development could be run into my home and on into the grid system for credit and retrieval later.
The big hang-up would be the up-front cost of the solar-electric generation system, which would pretty much be a deal-beaker, unless one could get a special low-interest loan and/or a tax break too.
The whole system should be incorporated into a complete solar-electric system for one's home, as is already commonly done. While certainly not cheap at all, it would get us away from so much dependence on gas if practiced on a wide-scale basis.
Yes, I'm aware that domestic solar-electric only a relatively small part of our total energy consumption, but we have to start somewhere.
Joe. :teeth :thup
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Joe,
You're absolutely correct.
If we could get away from fossil fuel electric plants, we're home free. Nuclear once offered that, but Chernobyl slowed that effort down, at least in the USA. I notice that France, England and Japan have a goodly supply of nuclear plants.
Now both my brother and I have solar power. Mischa uses that off-grid and stores the power in batteries. I am on-grid and store any excess power on the grid and just draw on that as much as I need (and more.) Two different models, and I think mine is the only workable one, since Mischa has to use a gasoline generator to augment the power.
We are probably a normal household for San Diego county which has plenty of sunshine and mild winters. This is probably the ideal spot for solar power. The solar panels are rated at 2.7 Kw and produce 5 Mw/yr and we use ~5.1 Mw/yr. That usage depends on if we're home in Sept. and how much air conditioning we need.
That system (panels, inverter, structure, wiring) cost $20K of which the state picked up 1/3. Since solar panel prices have dropped by 50%, one can get a bigger system for about $15K now. As usual, being in front has it's penalties.
We use propane for heating, clothes drying and hot water which of course are the big energy users. Going solar on that is beyond my capabilities. Whilst the panels are in back of the house (not on the roof,) to generate (and store, remember one only generates during daylight,) is beyond my capabilities and acreage. Charging a vehicle would also be a major requirement. 5 Mw, as our system generates in a year, would give you 67 Hp for 100 Hrs. That's enough 1/3 Hr/day for a year, or you could blow it on one big trip per week. If you want to assume 20 Hp average, that's 300 hrs/yr, etc.
Now San Diego Gas & Electric is trying to get power from solar farms in the desert. They are planning to buy it from people who put up those farms. However, the first site chosen in the Imperial Valley, while not on an Indian reservation, is claimed to be sacred by the Indians, though it was used for a bombing range since WW II. So that's put a stop to that for now. But Solar Power appears to be a great white hope and it's probably the only good thing SDG&E has done for awhile.
Boris
You're absolutely correct.
If we could get away from fossil fuel electric plants, we're home free. Nuclear once offered that, but Chernobyl slowed that effort down, at least in the USA. I notice that France, England and Japan have a goodly supply of nuclear plants.
Now both my brother and I have solar power. Mischa uses that off-grid and stores the power in batteries. I am on-grid and store any excess power on the grid and just draw on that as much as I need (and more.) Two different models, and I think mine is the only workable one, since Mischa has to use a gasoline generator to augment the power.
We are probably a normal household for San Diego county which has plenty of sunshine and mild winters. This is probably the ideal spot for solar power. The solar panels are rated at 2.7 Kw and produce 5 Mw/yr and we use ~5.1 Mw/yr. That usage depends on if we're home in Sept. and how much air conditioning we need.
That system (panels, inverter, structure, wiring) cost $20K of which the state picked up 1/3. Since solar panel prices have dropped by 50%, one can get a bigger system for about $15K now. As usual, being in front has it's penalties.
We use propane for heating, clothes drying and hot water which of course are the big energy users. Going solar on that is beyond my capabilities. Whilst the panels are in back of the house (not on the roof,) to generate (and store, remember one only generates during daylight,) is beyond my capabilities and acreage. Charging a vehicle would also be a major requirement. 5 Mw, as our system generates in a year, would give you 67 Hp for 100 Hrs. That's enough 1/3 Hr/day for a year, or you could blow it on one big trip per week. If you want to assume 20 Hp average, that's 300 hrs/yr, etc.
Now San Diego Gas & Electric is trying to get power from solar farms in the desert. They are planning to buy it from people who put up those farms. However, the first site chosen in the Imperial Valley, while not on an Indian reservation, is claimed to be sacred by the Indians, though it was used for a bombing range since WW II. So that's put a stop to that for now. But Solar Power appears to be a great white hope and it's probably the only good thing SDG&E has done for awhile.
Boris
Steam turbines used on nuclear powered submarines and possibly all steam turbines used in conjunction with a nuclear reactor do not super heat the steam and thus have at best saturated steam entering the turbine. As soon as you get expansion, you get condensate lowering the steam quality and reducing the thermal efficiency. The benefit or "efficiency" is not in the steam turbine but in the fact that you have a fuel supply that takes up the size of your bed and can produce thousands of HP for years on end.
-Mark
-Mark
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mark,
Thanks. That's better info than I have.
What you're saying is that the efficiency is lower than I estimated, but it doesn't matter.
Boris
Thanks. That's better info than I have.
What you're saying is that the efficiency is lower than I estimated, but it doesn't matter.
Boris