Fuel Cell vehicle from Honda

[dgipalo]

Autoweek had an article on the new FCX, due 2008. Looks interesting, and if the technology works as advertised, itll be a winner. Looks also like the REAL reason for automakers to work on hybrids: the development of propulsion and control systems for fuel cell vehicles.

http://www.autoweek.com/apps/pbcs.dll/article?AID=/20061023/FREE/61013008/1009

[N_Jay]

The idea of a prototype for sale to consumers is interesting.

Sort of the like the Chrysler Turbine car of the early 60's.

It should generate lots of excitement, but I am very worried about the real consequences of trying to move to hydrogen power before we have enough nuclear power to generate the hydrogen.

[Rapid Rob]

Originally posted by N_Jay
The idea of a prototype for sale to consumers is interesting.

Sort of the like the Chrysler Turbine car of the early 60's.

It should generate lots of excitement, but I am very worried about the real consequences of trying to move to hydrogen power before we have enough nuclear power to generate the hydrogen.

You DO have a sense of humour, N_Jay.

Who's in favor of more nuclear power? Hey, we could leave our X-Mas lights on year round.

[dgipalo]

Originally posted by N_Jay
The idea of a prototype for sale to consumers is interesting.

Sort of the like the Chrysler Turbine car of the early 60's.

It should generate lots of excitement, but I am very worried about the real consequences of trying to move to hydrogen power before we have enough nuclear power to generate the hydrogen.

Honda's been doing it for a few years, on a more limited basis. Not much different from other forms of 'beta testers'.

As to the fuel situation, if you notice further down in the story, Honda is also proposing selling a natural gas 'reformer/generator' station, thus taking aspects of the fuel issues away. Whether photovoltaic or nukes are the long-term H2 answer remains to be seen. A very efficient fuel cell, coupled to a efficient electric power-train could easily exceed the net thermal efficiency of an Otto cycle engine, even allowing for reformer losses. And if you harness those losses to something productive like heating water or the house, the net efficiency would easily improve on the Otto cycle engine.

[N_Jay]

Originally posted by Rapid Rob


You DO have a sense of humour, N_Jay.

Who's in favor of more nuclear power? Hey, we could leave our X-Mas lights on year round.

More nuclear power is the only way hydrogen based transportation ever can become practical.

[N_Jay]

Originally posted by dgipalo

. . . A very efficient fuel cell, coupled to a efficient electric power-train could easily exceed the net thermal efficiency of an Otto cycle engine, even allowing for reformer losses. And if you harness those losses to something productive like heating water or the house, the net efficiency would easily improve on the Otto cycle engine.

I am doubting those numbers. Do you have a link?

Our natural gas distribution system would be seriously taxed if transportation was added to the load.

Also, natural gas is a very good fuel for some very specific uses like domestic heating, hot water, and cooking. Why would you want to drive the cost up by putting that in competition with transportation?

[dgipalo]

Originally posted by N_Jay


I am doubting those numbers. Do you have a link?

Our natural gas distribution system would be seriously taxed if transportation was added to the load.

Also, natural gas is a very good fuel for some very specific uses like domestic heating, hot water, and cooking. Why would you want to drive the cost up by putting that in competition with transportation?

A fair number of them. Most are at 'prototype' stage, so considerable engineering development will be needed. One example of a prototype (research level) is Reformer based on Diesel fuel

Another comment on fuel cell efficiency: Fuel Cell Efficiency link . Note that the efficiency will have variables; the load on the cell will determine the losses, and fuel form storage will also create losses; LH2 will be amongst the worst. Compressed H2 less so, due to elimination of boil-off and cool-down cost. Assuming fuel cell efficiency of 50% of H2 energy, 80% conversion efficiency, you get to a power conversion in the 40% range; perhaps a bit optimistic, but reachable.

Conversion efficiency for CH4 to H2 + CO2 in a good reformer would run around 80%; same article, a bit further down. Assuming a heat re-capture from the reformer, this would keep the overall rate for Notarial Gas to compressed H2 in the 60% range (compression of H2 as a loss, slight gain; actual would depend on implementation). The overall BTU or NG to energy of motion would be in the 20% to 40%, well within the range of the Otto cycle engine.

Note that a 'good' Otto cycle engine will, at peak efficiency, have approximate energy conversion rate in the low to mid 20% range. That's potential BTU in the fuel, converted to mechanical energy LINK: Encarta link on Otto cycle efficiency

All of these estimates are 'optimum' or 'best case' estimates. In 'average' use, the Otto cycle engine is quite a bit less efficient due to pumping losses. It's the prime reason Honda does VCM on the Oddy and 2wd Pilot: to eliminate the pumping losses at light loads. Also the big reason that Diesels are relatively more energy efficient. The Pilot engine, in 'average' use, is likely less that 10% efficient at converting the energy in gasoline to forward motion. And this completely ignores any losses in fuel distribution infrastructure for gasoline.

A fuel cell, once developed, would easily beat that, by its very nature; it's more efficient at light load than at full load, and most of us don't drive at anywhere near full load on the engine.

I'm not saying that a competitive fuel cell vehicle is going to be in your Honda dealer's showroom next year. The article above acknowledges as much, as the FCX is a 'beta version' in just about any way you may want to name. Honda is betting that they can develop it, and make it a viable business. Given their success in a number of areas, I'm more inclined to believe them than not.

[N_Jay]

Thanks dgipalo, Good information.

I am not sure the numbers add up though.

Comparing efficiency of different engine systems using different fuels is very difficult.

Since Fuel cells are not available yet as a transportation energy system, I tend to discount comparing the "theoretical" or "future" efficiency to today's engines. The numbers presented for fuel cells should be compared to the best "lab environment" Otto cycle engines. With diesel technology hitting 40% and the curve still improving, I think Fuel Cells have a way s to go to break even.

One issue that most people miss, is that fuel cells are not a new technology, and while improvements are being made, they are small refinements. I believe that many people think of fuel cells as a new technology that us rapidly coming up the curve, and therefore expect large advances in a short period of time.

Driving fuel cells off gas and liquid hydrocarbons is interesting, and probably required for their adoption, but is a significant detractor to their ability to help with our energy dependence on fossil fuels.

If you want hydrogen power, you have to get it from nuclear. (Unless a miracle occurs)

[Bill Balmer]

Originally posted by N_Jay
One issue that most people miss, is that fuel cells are not a new technology, and while improvements are being made, they are small refinements.

According to the AutoWeek article, since 1999, the fuel stack has been reduced in size from "roughly the size of a small coffee table to that of an overworked CPA's breifcase" and output has increased roughly 40% every three years during the same time period.

I'd consider those significant improvements.

[N_Jay]

Originally posted by Bill Balmer


According to the AutoWeek article, since 1999, the fuel stack has been reduced in size from "roughly the size of a small coffee table to that of an overworked CPA's breifcase" and output has increased roughly 40% every three years during the same time period.

I'd consider those significant improvements.

There is something wrong with that quote.

Either size has been reduced (for a given output) or output has increased (for a given size).

The structure of that quote (if accurate) would lead me to believe the author did not understand the topic he was writing about well enough to give me confidence in the information.

Yes, the size has come down, but I don't think that drastically from what I have seen. What has not gone up much, if at all is energy conversion efficiency. This is the critical parameter in the alternative energy race.

[Bill Balmer]

Remember that the article in question is discussing the use of the technology in the context of powering a passenger car. The size of the cell necessary for this task has been reduced and at the same time the efficiency has increased, giving the vehicle extended range.

Maybe it wasn't the author who didn't understand the topic?

[N_Jay]

Originally posted by Bill Balmer
Remember that the article in question is discussing the use of the technology in the context of powering a passenger car. The size of the cell necessary for this task has been reduced and at the same time the efficiency has increased, giving the vehicle extended range.

Maybe it wasn't the author who didn't understand the topic?

If you have been following fuel cell advances, you would know that the reference to "output" can not refer to efficiency, because it has not increased anywhere near those numbers.

I take "output" as output for a given size, which sounds about right.

Most of the size reduction has come from manufacturing methods and not improvements in the basic fuel cell.

[rocky]

An oldie but a goody

http://hondapilot.org/forums/showthr...&highlight=FCV

[dgipalo]

Originally posted by N_Jay


There is something wrong with that quote.

Either size has been reduced (for a given output) or output has increased (for a given size).

The structure of that quote (if accurate) would lead me to believe the author did not understand the topic he was writing about well enough to give me confidence in the information.

Yes, the size has come down, but I don't think that drastically from what I have seen. What has not gone up much, if at all is energy conversion efficiency. This is the critical parameter in the alternative energy race.

The fundamental issue with PE membrane technology has been one of keeping the moisture levels 'just right' and removing the excess heat. Both of these issues are classic materials and design engineering issues, as well as a measure of manufacturing technology thrown in, for good measure. Energy output density depends on being able to manufacture a 'stack' that will produce the required energy output, and not melt itself down. This is the area that Honda seems to have made considerable advances in.

The other issue that the article (and Honda's press release) are mum about is cost. The catalyst most commonly used is relatively expensive, and the quantities needed with the current designs are way too much to have it price-competitive. If Honda has developed manufacturing techniques that reduce the amount of the catalyst necessary to achieve the output, then it's truly a break-through.

BTW, a viable fuel cell will allow a vehicle like a Prius (or some of Toyota's other models) to do away with the Otto cycle engine. The Ni-MH (Or LI ion) batteries complement the fuel cell to give 'burst' power for acceleration. This allows a fuel cell to gentry ramp the output up and down, rather than be concerned with the 'bursts' of high power demand needed for 'normal' driving. Honda would have to do a re-think of their hybrid tech to make it work with a fuel cell. Not necessarily a biggie, but it shows why hybrids aren't the tech dead ends; they are allowing the manufacturers to get engineering and manufacturing expertise needed for the next gen powertrains.

[Bill Balmer]

Originally posted by N_Jay
"output" can not refer to efficiency

You're right - bad choice of words. Still, I stand by my point that you failed to consider context in your criticism of the original quote. It seems clear to me that they're saying they have reduced the size of the stack due to an increase in output (for a given size) that makes it possible, and they are now using a smaller stack with a greater output compared to what they had 7 years ago.