[ohanian]

$this->bbcode_second_pass_quote('smiley', '
')
2500 kg's of car to transport a 70 kg person is a preposterous proposition no matter how you trick out the engine,

If you are serious about increasing fuel efficiency you should look at reducing the weight of the cars. It is by far the cheapest, least complex and most effective way of increasing efficiency.

[whereagles]

ohanian, your "P = M A V" is quite incomplete. It is valid only for an accelerating car without friction.

By the way, the efficiency of an ICE is more complicated than applying the efficiency formulas of an heat engine. An ICE's efficiency has more to do with compression rates and chemical dynamics of the explosions than with reservoir temperatures. I think there's poster working in the automobile industry; maybe he can explain this better.

[jbeckton]

$this->bbcode_second_pass_quote('whereagles', 'o')hanian, your "P = M A V" is quite incomplete. It is valid only for an accelerating car without friction.

By the way, the efficiency of an ICE is more complicated than applying the efficiency formulas of an heat engine. An ICE's efficiency has more to do with compression rates and chemical dynamics of the explosions than with reservoir temperatures. I think there's poster working in the automobile industry; maybe he can explain this better.

[whereagles]

It is quite true that reaching Carnot efficiency in an ICE is a mere paliative. But it's not downright useless because efficiency gains are always important, even more so in a time of scarity.

[invest_in_politics]

One aspect of Dr. Tinker's discovery that I haven't mentioned is that, if an engine can be made 30% more thermodynamically efficient, a 30% smaller engine can be used to get equivalent performance. So, provided that the paper's prediction of "simple" modifications equates to modest or no large percentage increases in weight per horse power, fuel economy can be increased above the 30% thermodynamic efficiency enhancement.

Another subject of that paper is the theory's ability to, again, accurately predict the efficiency of Stirling cycle engines. I see from previous posts that such engines are also of interest to the posters. No other heat engine model is as capable of predicting observed heat engine efficiencies as Dr. Tinker's. And it appears to do so for such a wide range of engine types and configurations that it is probably universal.

As for the statement that "even a Carnot engine wouldn't save us now," I would submit that there is, apparently, nearly 3 trillion barrels of oil available in oil shale formations world wide ( http://en.wikipedia.org/wiki/Oil_shale ). Since there is presently an energy cost of 40% to mine these deposits, that is reduced to 1.8 trillion barrels of usable oil. At current usage levels of around 30 billion barrels per year, that means oil shale could extend the use of petroleum-fueled internal combustion engines by 60 years. If ICE efficiency were increased by 30%, then the number of ICEs in use worldwide could increase by 30% and that 60 year number would still apply.

Beyond that, nuclear-powered production of hydrogen as an ICE fuel would essentially extend the availability of fuel indefinitely. This would eventually result in the use of whatever hydrogen-energy conversion apparatus that was most efficient. Dr. Tinker's discovery may make that apparatus the internal combustion engine.

IIP

[Kingcoal]

Look at the big picture. A bus with most of it's seats filled is vastly more efficient than a Prius hybrid. Better yet, an 8 car passenger train with half it's seats filled... In other words, I think that the one car per person paradigm isn't workable today or in the forseeable future. Peak oil is here now.

[invest_in_politics]

...and a bus or train with a 30% more efficient powerplant is more efficient still.

IIP

[jbeckton]

$this->bbcode_second_pass_quote('invest_in_politics', 'O')ne aspect of Dr. Tinker's discovery that I haven't mentioned is that, if an engine can be made 30% more thermodynamically efficient, a 30% smaller engine can be used to get equivalent performance.

[jbeckton]

$this->bbcode_second_pass_quote('invest_in_politics', '.')..and a bus or train with a 30% more efficient powerplant is more efficient still.

IIP

[MonteQuest]

$this->bbcode_second_pass_quote('invest_in_politics', ' ')As for the statement that "even a Carnot engine wouldn't save us now," I would submit that there is, apparently, nearly 3 trillion barrels of oil available in oil shale formations world wide ( http://en.wikipedia.org/wiki/Oil_shale ). Since there is presently an energy cost of 40% to mine these deposits, that is reduced to 1.8 trillion barrels of usable oil. At current usage levels of around 30 billion barrels per year, that means oil shale could extend the use of petroleum-fueled internal combustion engines by 60 years. If ICE efficiency were increased by 30%, then the number of ICEs in use worldwide could increase by 30% and that 60 year number would still apply.

Beyond that, nuclear-powered production of hydrogen as an ICE fuel would essentially extend the availability of fuel indefinitely.

[MonteQuest]

$this->bbcode_second_pass_quote('invest_in_politics', '.')..and a bus or train with a 30% more efficient powerplant is more efficient still.

[jbeckton]

$this->bbcode_second_pass_quote('MonteQuest', '')$this->bbcode_second_pass_quote('invest_in_politics', ' ')As for the statement that "even a Carnot engine wouldn't save us now," I would submit that there is, apparently, nearly 3 trillion barrels of oil available in oil shale formations world wide ( http://en.wikipedia.org/wiki/Oil_shale ). Since there is presently an energy cost of 40% to mine these deposits, that is reduced to 1.8 trillion barrels of usable oil. At current usage levels of around 30 billion barrels per year, that means oil shale could extend the use of petroleum-fueled internal combustion engines by 60 years. If ICE efficiency were increased by 30%, then the number of ICEs in use worldwide could increase by 30% and that 60 year number would still apply.

Beyond that, nuclear-powered production of hydrogen as an ICE fuel would essentially extend the availability of fuel indefinitely.

[MonteQuest]

$this->bbcode_second_pass_quote('jbeckton', 'B')esides, as we have seen, if the ICE has been evolving for 100 years and improving thermal efficiency while actually dropping in fuel economy, what makes the OP think that increacing the efficiency of the engine will now all of a sudden lead to increacing fuel economy?

[invest_in_politics]

$this->bbcode_second_pass_quote('jbeckton', '')$this->bbcode_second_pass_quote('invest_in_politics', '.')..and a bus or train with a 30% more efficient powerplant is more efficient still.

IIP

[invest_in_politics]

$this->bbcode_second_pass_quote('jbeckton', 'W')hat happened to the OP

Have you conceded that any improvements to the efficiency of the ICE would not transalate into increased fuel ecomomy?

Thats what started all of this.

[MonteQuest]

$this->bbcode_second_pass_quote('jbeckton', 'H')ave you conceded that any improvements to the efficiency of the ICE would not transalate into increased fuel ecomomy?

[SolarDave]

$this->bbcode_second_pass_quote('invest_in_politics', '')$this->bbcode_second_pass_quote('jbeckton', 'W')hat happened to the OP

Have you conceded that any improvements to the efficiency of the ICE would not transalate into increased fuel ecomomy?

Thats what started all of this.

[invest_in_politics]

$this->bbcode_second_pass_quote('SolarDave', 'I') gave this discussion up for lost long ago, but let me jump in on this one point.

Dr. Tinker appears to have made a breakthrough in the modelingof heat engine thermodynamics. That's all.

All you yahoos reading way too much into that are assuming the predictive power of his model is also of breakthrough proportions. Yes, assuming.

There is no physical evidence whatsoever to back up his model or to demonstrate its predictive accuracy.

Back to the fun!

[Gerben]

Many engine manufacturers are already 'Tinker'ing on their engine designs in an attempt to improve performance. Some examples:
NoNox: www.nonox-bv.com
GoEngine: www.gomecsys.com

[malcomatic_51]

I will add what I can to this discussion. I have been involved in both Diesel and gas turbine research, development and component design, this may provide useful reference for the discussion.

You can be assured that all manufacturers invest immense sums to achieve the maximum possible efficiency for industrial engines. Industrial engines include truck engines, military vehicles, and engines for ships and aircraft. These machines are sold to highly technically literate industrial customers who are only interested in cost, reliability, fuel consumption, ability to pass regulations and after-sales service.

New engines coming into service are always the best that can be done with the state of the art. There is no conspiracy to hold back miracle technologies. Advantageous technologies are introduced immediately to gain competitive advantage. The manufacture of prime movers is extremely competitive, with low profit margins all around, except for General Electric of America, which has a huge inbuilt advantage from its profitable spares and after-sales service to the immense US installed base of electric power plant (most of which is GE technology).

There are ways to increase efficiency, which are well-known but are not commonly taken up by the market. For instance, truck engine efficiency would be higher if you put a turbine in the exhaust and geared the turbine to the drive shaft to increase power for the same fuel burn. This is known as compounding, it is well-known amongst makers and users of engines. The Lockheed Neptune reconnaissance aircraft used an early compound engine for very low fuel consumption, but at the expense of weight. The basic trouble with compounding is that it is usually more hassle than it is worth, because the complexity increases cost and reduces reliability.

If fuel prices became very high, that might shift the balance to make compounding more attractive.

An extremely effective means of improving efficiency is combined cycle. In this arrangement, you have a gas turbine with a boiler in the exhaust pipe to catch the waste heat and run it through a steam turbine. This became popular in the late 1980s, when exhaust temperatures got high enough to make it appealing (it had been known about for decades, but the gas turbine materials were not yet fit to allow high enough exhaust gas temperatures). A combined cycle plant is the most efficient prime mover ever produced by humanity, with a thermal efficiency of over 60%. I think this system has been tried experimentally in truck engines, but like any turbine system, it does not suit varying speeds.

The way forward in engines has been known since engines were first built early in the 18th century. Always one seeks higher temperatures and pressure ratios. By the turn of the 20th century the science of thermodynamics was advanced enough that the efficiency of any engine could be predicted fairly reliably just by knowing the maximum temperature and the pressure ratio. An engineer in 1900 could have predicted the efficiency of the most modern jet engine in this way. I can predict future engine efficiency in the same way.

Engines that rely on differences in temperature can never be 100% efficient. This limitation is because a heat engine relies on a flow of heat, and to have a flow of heat you have to have a cold "sink" into which you can dump the low-grade waste heat at the end of the cycle. If you're at the South Pole or up at 40,000 feet you've got a lower sink temperature than in the Sahara desert. That's why jet engines are so much more efficient at altitude than at sea level.

Not all engines rely on heat flow. There are isothermal processes that can theoretically be 100% efficient, but they are all too awkward to make as practical engines.

By the way, coal-fired aircraft are not completely out of the question. The Nazis experimented with building a giant steam turbine powered bomber to bomb New York from Germany during the last war. They never finished a prototype, but the idea is feasible (if very much a second class option to what we use today).