Ceramatec are the people behind the sodium sulfur 200 Wh/kg battery with their patented membranes, same as here. That didn't exactly pan out, it disappeared quietly and I couldn't find one word of information why. Who says this will not suffer the same fate?

I wonder what the extra price is for the rankine cycle. This has always seemed very interesting to me and in the past there have been many attempts at a rankine bottoming cycle. Maybe now technology and fuel prices have now reached the point that the cost and complexity premium is acceptable and paid back within X years?

[sarcasm]An alloy with only 8% Gadolinium. Considering gadolinium prices, it is good to see that this will finally enable mass production of a cheap, lightweight and ultra strong magnesium alloy.[/sarcasm]

Aluminum per weight is a lot more costly than steel, only because you need less of it, it doesn't cost THAT much more.

"while the charge process is the direct oxidation of Li2O2 into O2" WTF? Shouldn't charging be the direct REDUCTION of Li2O2 into LITHIUM METAL?

I agree that the useful figure would be to compare energy per mol using this approach vs. Haber-Bosch process. Considering ammonia production accounts for a few percent of the world's energy consumption, a more energy efficient route would be a significant development (throughput is also important as mentioned). Reacting hydrogen with nitrogen should in principle at least allow the PRODUCTION of energy, due to the unreactivity of nitrogen in practice a lot of energy is CONSUMED creating the enormous pressures and high temperature for the reaction with a catalyst.

Shouldn't that read 118 mpg-e for the e-jet concept? No way it actually consumes 2 liter per 100 km.

"There is just the small matter of programming it." LMAO. I'm currently working on image processing for recognizing the weft yarn on a loom, something seemingly simple. Small matter indeed. There's probably a reason why Google's driverless cars got a pass in California, no snow and lots of good weather.

Keep in mind also that diesel is more energy dense per unit volume than gasoline. That also adds considerable advantage in the seeming energy efficiency for diesel. The actual energy efficiency difference between diesel and gasoline is considerably less when comparing per kg of fuel instead of per liter.

E-P, the theoretical figure of 550 Wh/kg for lead acid which you provide is a bit too high, it seems more like 120-170 Wh/kg depending on the source (and voltage and concentration of acid, up to 218 Wh/kg mentioned for 100% concentrated sulfuric acid and voltage 2.6V).

Keyword being "up to". Since aluminium production is way more energy intensive than steel, those hundreds of kilos of aluminium correspond with multiples hundreds of kilos of fuel consumption in its production extra, that the fuel consumption reduction in use will have to slowly offset and hopefully improve.

Since for a car of 1.5 tons a hydraulic brake recovery system weighs like 100 kgs or so, can I extrapolate for a passenger rail cart of 60 tons that system will weigh like 4 tons or so to be installed somewhere under the floor? Also, for both the hydraulic system and the flywheel, that seems like a high explosive system waiting for an accident. For the flywheel either lots of shrapnel shredding you to pieces or carbon fiber fragments into your lungs, for the hydraulic accumulator the flying spaghetti monster knows what. As long as things go right, you'll be fine though.

I am sorry, but no one at this point is really disputing that intercooling can make an engine more efficient so your lectures would be pointless. I still don't see what your main issue with E-P is about. The biggest issue that I have with any of your claims is as E-P that cooling between compression and combustion could improve thermal efficiency. There seems some misunderstandings on all parties though as to the exact impact of intercooling on thermal efficiency. I was wrong previously in using a way too generalized statement on the effect of intercooling on thermodynamic efficiency. Since intercooling in practice is ALWAYS used with super/turbocharging in a reciprocating internal combustion engine, it can make an engine more efficient even in simple thermodynamic cycle analysis. If however no or too little super/turbocharging were to be used and compression ratio were to remain the same, then I do maintain intercooling would be detrimental to thermal efficiency in simple cycle analysis. Such a thing is however not realistic as you cannot stop compression mid cylinder stroke to cool the charge and then compress it further. In a Brayton cycle turbine it is generally accepted in simple thermodynamic cycle analysis that keeping other cycle parameters the same, intercooling alone is detrimental to thermal efficiency. E-P gave a link to this which I didn't bother reading and ended up linking to again myself. FYI, I am Belgian (are you Dutch or German?) while as Engineer-Poet is American. I'm a civil engineer, specialty in textiles. I graduated in 2001. I had thermodynamics in my second year only (1998) so my skills are a bit rusty.

"So, what about the last experimental data I posted on the two Scania engines? Could I prove to you this time that intercooling is efficient, or do you need more evidence?" As previously mentioned, I don't doubt you on the technical or experimental aspects of engines you post and even E-P acknowledged that an intercooled engine CAN be more efficient.

"Well, you have to refer to where you get the information. I anticipated that it was your own words." I posted the reference right at the very top of the post, impossible to miss it. "It seems as you deliberately left out information from the answer" I posted the relevant part. I did put in a later post that it was an EXCERPT. Obviously, you have failed to note that, you only read what you want. And you don't read what you don't want. That's why I posted that excerpt in the first place. I know very well at Aumet they want to make an efficient engine otherwise there would be no point of switching from a conventional Otto or Diesel engine to anything else and they wouldn't get investment. Yet there has to be a reason why they answered "Yes it does." to a decrease in efficiency, isn't it? Or are they idiots too?

"If you have theories about thermodynamics, why don’t you post your calculations to prove your point?" Intercooling and reheating will always decrease the thermal efficiency unless they are accompanied by regeneration. This is because intercooling decreases the average temperature at which heat is added, and reheating increases the average temperature at which heat is rejected. http://web.me.unr.edu/me372/Spring2001/The%20Brayton%20Cycle%20with%20Regeneration.pdf>The Brayton Cycle With Regeneration This is a general statement about the thermodynamic aspect. It doesn't mean that by modifying other cycle parameters, such as compression ratio for example as allowed by intercooling, that thermodynamic cycle efficiency can't be increased again. Generally however, keeping the other parameters of the cycle the same, thermodynamic cycle efficiency does decrease by intercooling. This is generally accepted knowledge in thermodynamics. I'm too lazy to do the calculations myself so I refer you to example 2 on page 12 for actual calculations for a very simplified cycle analysis that intercooling and reheating without regeneration decrease efficiency. There is however for example also a paper called: "Raising cycle efficiency by intercooling in air-cooled gas turbines": http://www.mendeley.com/research/raising-cycle-efficiency-intercooling-aircooled-gas-turbines-5/# Which shows thermodynamic cycle efficiency of a brayton cycle gas turbine CAN be increased by intercooling. This is however when taking cooling air requirements into account in the thermodynamic cycle analysis. So it depends on what you take into account in your thermodynamic cycle analysis. If in your case, you modify the cycle by changing compression ratio from 8:1 to 10:1 and take cylinder wall heat losses into account in a more detailed thermodynamic cycle analysis, sure, intercooling can increase cycle efficiency of this modified cycle. However, in the most simplistic case and analysis, the general statement that intercooling and reheating without regeneration decrease efficiency is true. So I don't see what the bickering is so much about.

"You had a question about the Aumet engine and boldly you also provided an answer." No, I copied and pasted an excerpt from the faq of the site you posted. I did not answer anything.

Peter XX on record: "If the air temperature increases from the low level of ~40 deg. C in either the low-pressure (LP) CAC or the high-pressure (HP) CAC, SFOC increase significantly. If the MAN engineers would listen to the thermodynamic theories of a Poet, they would remove the charge air coolers. I do not think they are that stupid." What I see: intercooling can make an engine more efficient. Engineer-Poet on the record: "While I'd be the last to argue that an intercooled engine cannot be more efficient than one without intercooling (just the downsized mechanical section and reduced compression back-work are solid advantages..." What I see: intercooling can make an engine more efficient. I do however also see that as far as the theoretical aspects of thermodynamics are concerned, E-P is the one that has it right. I do not doubt Peter XX on the technical aspects of engines in what he posts.

http://www.aumet.fi/html/faq.htm Q: Doesn’t the intercooling after the piston compressor decrease the overall efficiency, when heat is removed from the process? A: Yes it does.

"You must realize that an increase in compression ratio by two units, e.g. from 8:1 to 10:1 has a decisive impact on fuel consumption in this case." Now I better understand the source of your claims. Thermodynamically speaking, if you keep things like compression and expansion ratio and maximum temperature the same but if you cool in between expansion, you have a lower temperature after compression and hence a lower average temperature of heat addition, which thermodynamically speaking reduces efficiency as E-P rightly claims. If you however modify other things like expansion ratio, maximum temperature or in your example compression ratio, of course it is possible then that even thermodynamic efficiency increases (as average temperature of heat addition can even increase if you raise compression ratio enough) but then it is comparing apples to pears with regards to thermodynamic cycles. E-P is right in that intercooling would detract to the efficiency of the (Carnot) engine keeping the rest of the cycle the same, but you are right in that by changing the parameters of the cycle (you changed the cold source temperature in the Carnot cycle or the compression ratio in the diesel/otto cycle) as allowed by intercooling you could increase thermodynamic efficiency.

By the way, Brotherkenny, you seem to know more of batteries than me. I've read frequently that the solubility of sulfur in the electrolyte is the main problem, yet at the same time I've read that some Japanese company developed a Lithium conducting membrane dubbed LISICON, sounding similar to Ceramatec's NASICON. Wouldn't this be part to a solution for Li-S chemistry and why don't we hear more of that?

I assumed when you mentioned fuel efficiency as on a certain cycle like NEDC. Such a cycle is not at optimum efficiency. I thought peak thermal efficiency of an intercooled engine was usually somewhat less (2% or so) due to the reduced thermodynamic cycle efficiency outweighing the benefits from reduced cylinder wall losses during compression etcetera. Anyway, I must have recalled that wrongly as you can't really compare different engines/engine designs "on average".

E-P: after reading his post thoroughly, it seems Peter_XX interpolated from INTERcooling, where most of the compression is done in the cylinder anyway, that COOLING after compression could increase efficiency too due to what he assumes is better combustion efficiency. I find this highly dubious as it is indeed a big loss, you don't gain anything from reduced heat losses to the cylinder wall during compression and what you gain from combustion efficiency is probably quite little. I don't recall figures for combustion efficiency differences between diesels and gasoline engines but a diesel is regardless of its higher peak combustion temperatures and condequent lower combustion efficiency and more constant pressure like heat addition STILL considerably more efficient than a gasoline engine due to compression ratio alone. I'd bet on it being a considerable net loss despite improved combustion efficiency.

I also don't doubt anything you said apart from thermodynamic cycle efficiency. I did not know the figure for fuel consumption reduction was about 5%. I thought peak thermal efficiency was lower by 2% or less. Do you have figures for that?

That is increased engine efficiency, which I don't doubt is possible. Thermodynamic cycle efficiency is still less. There is less work in compression but that means you end up with a lower temperature after compression and will need to add more fuel to get a temperature rise to get the same work from expansion. Net effect in thermodynamic cycle analysis is a decrease in efficiency. But anyway, a gasoline engine does not come even close to the ideal Otto (constant volume heat addition) cycle efficiency nor does a diesel come close to the ideal constant pressure heat addition cycle. Thermodynamic cycle efficiency is idealized, what many don't know is that it does not even produce power (since it is infinitely slow) and hence does not take things like part load into account (as load means power).