Why not a sterling?
I think its technology we can still not ignore.
Your wood gasifier wold not have to make clean tar free gas for one things.
I wonder what this truck woudl have been able to do with one of those 10 speed ZF tranmissions they sell now?
I am no expert, but it seems to me the reason IC piston engines are ubiquitous is not because they are ābetterā but because they are profitable. People want fuel efficient car because they save money, but it doesnt seem to me that they are willing to sacrifice much (if any) performance to get it. That stirling truck that nasa built was pretty cool, but 75hp? The MPG would have to be phenomenal to sell something like to John Q. Average. The lower maintenance cost sounds great too, but again, whats in it for the car company? Parts and service are a huge moneymaker for dealerships. And if it never wears out, how are they going to sell you another one?
This is a fascinating debate, and lots of cool technologies on display, but capitalism picks winners by how much money they can rake in. That seems like a bad way to assess quality to me 
Torque like a steam engine.
75 HP with peak torque at a start would be like Jay Leno said about his steam car.
Like the hand of god pushing you.
Really 75 Hp is plenty in a truck unless your towing.
Slant six in the truck as built was probably only around 100-120 hp, and that was plenty for most people at the time.
Enough for meā¦
More info from the report.
From what I gather there was a long warm up time before you could drive.
But it was efficient enough durable enough and could have been done.
I am enjoying the discussion too, I feel itās a good examination of notions around power production, and performance.
And agreed, price and market dynamics canāt be relied on as indications of what is best.
Why does a Stirling need to be heated to damaging temperatures? It seems this is only necessary if comparing directly to an IC system. I see this as equivalent to comparing a small car to a tractor. With appropriate gearing and high enough revs, maybe boost, the 4 cylinder could technically put out the HP to drive the tractor. Probably at metal glowing temperatures, and not for long. Instead of idealism, I call that realism. Use any system to itās best advantage, within itās realistic limits.
Do I care that much if my generator weighs another 50 pounds? Not nearly as much as that it works. And remains reliable. If I could fire it on charcoal, sawdust or firewood, Iām actually excited by the prospect. Linear Stirlings promise far greater service life, and virtually no maintenance, which is why they are the goto power plant in solar thermal electric.
IC is king as long as thereās pump fuel, and oil for oil changes, and a full parts supply.
Another thing that interests me about this debate is an apparent underlying notion that we can never accept anything less than current convenience. That is how people drive off financial cliffs, civilizations off resource cliffs. Those who adapt their outlooks do better. Do I care so much if it takes 15 minutes for my generator or pump to power up? Not nearly so much as not having power at all to do necessary work, or an empty gas can. I wouldnāt care any more than my ancestors cared about firing a steam engine, or walking the horses out to the field. They were just glad they didnāt have to do it āthe hard wayā.
Convenience is relative. Shaft power and electricity are the awesome prizes.
This is part of our new journey with full auto control systems combining the systems with battery storage. The mind set is wrapped around wind and solar. The thinking is build it big enough to take advantage of energy harvesting as much as possible into a large bank. With our system we have to think differently, we make the power on demand. We no longer need a giant storage system. But we do need to find balance where we get the most efficiency, When CHP is considered then we dont want to run for 8 hours a day and off the rest of the day. We want to maintain heat systems such as hot water and then also supplemental heating. So a smaller battery bank makes better sense lowers the over all cost to implement. We want to cycle multiple times a day. We may later make the machines able to run on a schedule as well. It would run in a normal cycle run mode but could be set to run before bed regardless to top off and make the machine go into a sleep mode with the rest of the neighborhood. lol then in morning hour we can tell it to check status and then go back into normal cycle mode. 
A wood gas combined ICE power system I guess we would consider both? Right? That 30% we lose making product gas should be factored in the process in the combined system. So it is both external and internal. 
No, I didnāt miss that. You miss my point. Maybe Iām not clear. I said ICEs rule the day. Meaning that though they are here today they may be gone tomorrow. All it would take is the development of some new material, or method of heat transfer, or some simple thing I canāt even imagineā¦ I think the whole woodgas thing is great, but I hope itās just part of something bigger. I think we, as a society, just sort of stopped doing a lot of creative things after the second world war. Yes, ICEs are the way we do it, but I think its at least worth looking at these other ways of doing things too. Example: Okay so a steam powered chainsaw probably wouldnāt work very well. Could we use a superheated jet of steam to cut the wood directly? Never mind me Iām just a crazy old coot with a head full of funny ideas.
Rindert
Thats why Im looking at Solid Oxide Fuel Cell technology and wood gas is the perfect solution to provide the fuels to run them. They are now in the 60% efficiency range and will get better in time.
O.K.
Iāve so far given you three ways to evaluate my rather bold statement:
The fact that an internal combustion piston system ONLY has to part cycle fuel and uses the FAST temperature-pressure rise of that contained combustion for the actual power. Inside TP pulse to outside shaft power. Not the reverse energy-loser of any external combustion Shaft Power system.
The second reason Because the T-P does initiate internally contained Less system masses needed to get up-to, and be maintained at temperature, for best fuel-air ionization. External combustion system to approach the current best practices IC Piston have to get very, very complex in stepped pressure untilizers; heat regenerators; cycle loss energy closers. Complex takes more engineering/manufacture efforts/works. Complex takes More maintenance dependencies to keep functioning. Complex adds many more failure points. And all of the automation fine controls to make this Complex function seamlessly just adds more Tech-dependencies. More failures points.
My third point is a direct refutation of āwe only still use IC Piston engines because of easy-way known technology . . . because of short sighted-profitā. Wrong. Wrong. Wrong.
All of these named commercial shaft power engine system suppliers are extremely competitive against each other. We are long past the days of āWhat is good for GM, is good for Americaā. Long past the days of British engineering pride versus German engineering pride.
The market game now is provable results to the users. As it should be.
I have a b-i-l who will never buy a Samsung branded product ever again. Their better energy effiency duel-compressor refrigerator proved to have 2x more reasons to fail him.
IF a Wankel motorcycle was such a good thing Suzuki would still be making them further developed. Nope. Long distance motorcycle tourers voted for as simple and durable IC piston engine as they could get. Fuel economy. fewest break-down incidences. Lowest maintenance requirements.
IF Stirling cyle engines were oh-so-great, why not in working over the road trucks, eh? Be a great hit in cross-continental Canada, US, Australia, Russia. Fuel with whatever was cheapest available as you travel. Nope. IC piston engines in trucking rule for durability, fuel-use economy, and least maintenanceās. And even here, by-by, to 2-cycle oil burner/leakers. By-by, to ooh-rah big displacement V engines. Inline sixes rule because they proved the right balance for that usage-needs. Rail, actually needing more traction weight, then could scale up to the big V multicylinders.
Again. In our current world situations any multi-fuel-use external combustion shaft power engine system was even competitive with IC pistons, and one of the very prideful national governments would have pushed it (subsidized) into useage! You really think that the president-for-life now in Russia and China are beholding to a GM? A Toyota? A VW/Audi Group? No, they are not.
You really think that the clever Saudiās, or Iran regimes would not invest into a keep-in-power oil fuel stretching system?
They would.
Then, always been fuel-starved Japan. ANY system that would stretch out their 100% fuel imports would get pushed into usages. They really do the best possible, for very real to them, reasons. Canāt fuel use afford anymore any free-cheap-energy spin-spins.
This belief in a Designer Hero, out there . . .someday. The belief in an undiscovered energy-law, killer-app-battery, magic energy stone. This is all just fantasy-football. Low brow cheap entertainment by those not really willing to sweat-out real results. Results broadly applicable to enrich real lives. Not enslave lives on even more designer-tech-dependencies.
O.K.
A new fourth way to evaluate and compare IC piston to any external combustion engine power system.
TP power cycling time. Recycling time from combustion push, to next push.
An IC piston engine has the time-cycle that you design in, and a range the operator operates it in.
A four cycle IC piston engine has always beat out efficiency-wise a two cycle IC piston engine because it simply has more time (crankshaft angles of degrees) to fully harvest the TP pulse into shaft power. More time to fully cleanse out the cylinder/combustion chamber of energy spent gases. More time to recharge the cylinder/combustion chamber with a new air/fuel charge for the next power making cycle.
I do like 2-cycle IC piston engines and use them exclusively on all of my carry-about hand-held stuff. Power to weight there rules. My arms. My back. Stihl for a rime offered an intake? exhaust? poppet valved 2-stroke engine. Less emissions they said. More weight. More complexity. I passed easy, no-brainer on that one. Now no longer available.
Every motorcycle Iāve owned was a 2-stroke. 100cc through 500cc. Just me. I valued simplicity and lightest weight in this application above four-cycle better fuel economy.
My actual owned IC piston working engines power-pulse recycle at a rate of 600 to 7000 time in a minute.
Stirling? Any Stirling piston type must power-cycle at a much slower rate to be able to cool and reheat for itās power stokes. Not in power cycle is not making shaft power. Period.
And ALL of the time the hot end burner is fuel consuming.
Same for your turbines. All of the time you are fuels burning consuming. Turbines scale down to any personal usages terribly.
I am all about personal use systems. Period. Not an energy prophet/profit. Not a to-the-masses energy supplier.
Just the facts-of-it-man.
I am at the public library. On hand they supply wooden graphite pencils for notes taking. Iāve owned some pretty fancy ink pens including a couple of pressurized Fishers, a couple of guaranteed to Writ-In-the-Rainās. They all failed me at some point. Of course; only when I needed them.
A wooden pencil, 130 year old tech, still works and is used because it does works. Wet, underwater, in-space. And a pencil when not working, is easy-see, restore-able to working.
Woodgas is to self-made fuel IC Engines for useful purposes.
All of your better ideas and better-living techs to āimprove thisā just get in the direct-usages way. Fantasy-footballers . . . again.
Steve Unruh
On topic is the fact that IC piston engine systems will scale-down WITH EFFICENCY to personal sized units.
External combustion shaft power systems simply do not.
Two very modern 21st century IC piston engine based systems prove this well.
Hondaās EXLink home CHP system.
The engine details here:
this is a true extended out expansion cycle Atkinson-type 110cc engine, 12.2 to 1 c/r, 1950 rpm
five full development re-designs until they felt they could get it good enough for production useages.
end of article is a link to the whole-home power system they have been offering since 2011. on itās 3rd generation reversion.
The other is the American made Marathon EcoPower system. Uses a purposed designed water cooled cast iron slant cylinder engine as itās base. A former more refined engine system that began as a York stand-a-lone remote air-conditioning system unit power engine.
Intended as a natural gas or LPG fueled system.
System designed for a 5000-7000 hour between oil, spark plug and valves servicing. Once a year, annual.
Find the embedded links on their home site and you will see that they offer this up in addition to Residential and Commercial building CHP; but also as a stand-alone not-tied-in railroad switching, telecommunications, and remote weather station powering system.
Still a going operation. You will be able to search these up. If you actually try.
Same. Same. Situation. Low current in-use deployments means high buy-in prices. $15K for the Marathon engine IF you could get them to sell you one.
Use these real-in-this-world commercially available systems as test-points.
Can your DIY come even close to matching their IC piston engine performances?
Can the ochie-woocie; better-living (tomorrow) system; one every-one loves to jabber about, even come close? And that eye-candy system, of course not in deployment yet, let alone in 100,000ās real production batchās like the Honda EU2000ās . . . will be available, if m-a-y-b-e, you keep sending money, and giving them internet, talk-talk support.
S.U.
Free piston sterling cool idea
the Honda is being marketed as the Freewatt in the US It looks amazing!!! There are no full off grid models available yet but they are planned.
That EXlink engine is way cool. Thanks Steve.
Variable compression ratio on the fly was actually achieved long ago, by Anthony Michell. The drive system has become the basis of Diesel injector pumps.
http://douglas-self.com/MUSEUM/POWER/unusualICeng/axial-ICeng/axial-IC.htm#tech
Of course axial drives work well with steam too.
https://greensteamengine.com/licenses.htm
Rindert
Hello Mr Wallace,
Iāve seen this NASA propsed engine/electrical system before. Very tantalizing, eh.
On an inward sun spacecraft/satellite one side is high sun heated Hot, and the other side shadowed, space Cold.
Just what youād want to maximize the deltaT for best power.
As Iāve followed up on this it failed the NASA power system cut first because any reciprocating mass was felt to upset craft fine dynamics stability. (rock-solid not-stability: same reason for the decades flying-wing aircraft developments failures to put into service)
So, score one for continued use of NASA fuel-cells and PV solar.
Also the shown metal flexing parts on this linear-axis engine were determined to be a durability problem.
Realize in space exploration hardware design you really want the system to finally crap-out due to some other system component failure - NOT YOURās!
So no contract. No deployment. No availability to us common guys.
A dream-machine proposal.
RindertW, Iāve been time and time again re-introdued to this Green-Steam system. Has all of the four deficits points, Iāve detailed out with external combustion systems. Plus . . . a sure to fail metal flexing system too. Sure. Sure. Change that to carbon graphite composite. You just buy time, at great expense before that inevitable flexing failure. At best then instead of sparkplugs maintenance, then flex joint by-MTBF-hours, forced maintenance changing outs. Iād rather change out sparkplugs.
An eye candy; sent-us-your-money, sucker system. Do not be that fooled one. Pocket-book, and years-life-efforts ripped off.
Steve Unruh
Well is has taken a while to dig out claimed info on the Marathon engine.
272cc, operable from 1200-3600 rpm, for a flywheel mounted electrical generated power of 1kW to 5kW. What a wonderful woodgas engine system this would be.
So for the whole system synchronous AC power with variable engine speed then must have itās own inverter/clocked/converter system . . . wild AC to DC, to frequency/voltage regulated AC.
ONLY rated 24% efficient on fuel to shaft power versus the HONDA at nearly 50% higher conversion effnecy rated.
The difference I see is the HONDA system is primarily intended to be a super fuel sipper for high-fuel costs parts of the world. With electrical as primary, heat as secondary.
The Marathon engine/system is biased to making/harvesting heat primarily, then making electricity. Why they claim 93-97% fuel to energies conversion efficiency.
My point again is it does not take a woo-woo near āperfectā engine system to produce good results.
It is how that engine is used in a whole system to produce best results for the whole system user.
Ha! My one old-man regret is I am unlikely to completely wear out beyond use my wifeās cast off 2007 Hyundai Tucson before my license will be jerked.
I so much want to upgrade to a used 2nd generation Toyota Prius. Re-capture nearly all back of the slow-down braking energy Iāve been waste heat shedding off all of these years.
It is the life-cycle systems integration guys, with users allowed control. Not single point āperfectionsā.
S.U.
Errr, I wouldnāt use that flex drive either. Life in the the millions of cyclesā¦ I get that. But you donāt have to do it that way. If you sort of look inside all the work that guy at green steam did you realize that flex drive was just the first one of those he ever made and that he later used machined āZā drives. He realized his mistake. Hey, everyone has to start somewhere.
The concept of a swash plate or āZā drive is good. Diesel injector pumps go for a long time if treated right. Anthony Michellās engine could have used some more development work, granted. But the prototypes were very promising considering the amount of R&D that had gone into them.
Rindert
Interesting completely reading that douglas-self.com/MUSEUM/POWER/ site link that you put up RindertW.
Thanks.
These all were/are Internal Combustion Pistons engines.
The DynaCam engine as having the latest development work put into it.
I had been going to point-out your Michell engine for swash-plate friction until reading Michellās patent design/use self-forced lubricating bearing.
The DynaCam and the Russian axial engine designs are interesting as have variable rate movements drive/driven cam plates that could more match the TP combustion pressure curve fall off.
Many, many production automotive air-conditioning pumps also use swash plate connected axial multi-cylinders too.
Like the injector pumps: enclosed, pumped gas/fluid carry through minuscule droplet lube of the sliding friction points.
Actual internal combustion always had some piston rings blow-by of some combustion gasses.
Different environment than a sealed-use environment. Below piston areas in IC get soots, carbons and 3-4 different types of acids building ups.
In real world long life deployment a great deal of the durability usage of any IC engine design is how well it can handle, isolate, and lube change flush out these inevitable combustion contaminates of the mechanical gutsā¦
A big reason why oil-in-gas, mix delivery crankcase pumping, 2-strokes actually do so well for long life usages.
They self flush internally, continuously. Just a wee-bitāo problem with combustion chamber/exhaust outlet carbonizing if not ran loaded down and hot. That is easy de-carbonizations maintenance all-in-all.
Regards
Steve Unruh
Granted. And donāt get the impression Iām particularly sold on steam or anything else. I try to keep an open mind, and not rule anything out if I donāt have a very good reason for doing so. I remember a professor telling me that CVTs were completely worthless. As I listened to him more I realized that he had formed his opinion soley from having worked with the college MiniBaja team. Apparently they went through a lot of belts. I didnāt say anything but to me that one experience just wasnāt enough data to base an opinion like that on.
It is a little disturbing to me that I have never been able to find a mechanical engineer who knew who Thomas Newcomen was, or what an atmospheric engine is. I might build one of those, in dire circumstances. You could. All you would need is a junk pile. So what if efficiency is in the single digits? It was actually a usefull engine.
Anywhoo, Iād be interested to hear your opinion on those new fuel injected 2 strokes that Mercury outboards use. I like the concept of a 2 stroke at least. And if I remember right DDC made 2 stroke Diesel locomotive engines. I donāt know what happened to them. Were they just too dirty? I remember seeing one come out of Moffat tunnel pushing a cloud of black smoke in front of its self. Someone said the wind was in the wrong direction. Maybe I donāt think the EPA is all bad either.
Rindert
The 2 stroke, air atomized direct injection engine was developed by Orbital engines of Australia.
It was featured in concept cars by Pininfarina in the early 90s. The light engine allowed light everything, resulting in a car rated at 145mpg.
Ford bought a significant interest in the company.
https://www.carmrades-blog.com/all-articles/2017/11/24/failure-to-launch-the-orbital-engine-company
https://cardesignnews.com/articles/concept-car-of-the-week/2015/07/pininfarina-ethos
