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PostPosted: Mon Sep 27, 2010 11:11 am 
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BBlue wrote:
cheapracer, not trying to be argumentative, but if Aluminium is no lighter, why would anyone (at least OEM) mess with Aluminium for use in engine blocks? Aluminium introduces a lot headaches, expansion and warpage being obvious. Can that much be saved in machining time?

Bill


casting aluminum with thick sections is easier than casting cast iron alloys with thin sections.

I prefer welded mild steel myself. its way superior to both in terms of weight and fatigue life. its perfect for high efficiency micro scale manufacturing with automated plasma welding. even a crankshaft can be fabricated this way.


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PostPosted: Mon Sep 27, 2010 12:20 pm 
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dohh!! :oops: i suppose a picture would help, sorry about that.
Attachment:
big121719670809-03%20Scud_%20Top_%20Abarth%20850TC%20%20110mm%20Angled%20Cap.jpg
big121719670809-03%20Scud_%20Top_%20Abarth%20850TC%20%20110mm%20Angled%20Cap.jpg [ 7.83 KiB | Viewed 1200 times ]

110 mm(x2) rod length on a 55(edit 59mm) mm throw. throw is distance from rod pin to crank pin right? so add a factor to throw for clearance(80mm), add maybe 120(?)mm per head(x2), 34 mm for combustion height(x2). 220+80+240+68=608mm(624) or 23"(24 1/2)? crankshaft centerline would need to be some 7"(?) above the bottom of frame? you could probably get skinnier, here's a media release on the subaru 2 liter boxer diesel which unfortunately doesn't give the dimensions except to say that its smaller that the gas engine despite a longer stroke.
something else to consider with these that i had forgotten about is the offset introduces another moment arm. ..(i think)
a v would be interesting but i don't see a way to bolt that together.

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PostPosted: Sun Oct 03, 2010 9:42 pm 
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a.moore wrote:


I got to see that in person in 99(?), I think they fired it up a couple times in the paddock, but the car never made it to the track that year. Oh and if anyone is wondering why you'd bother to do that and end up with such a small displacement, it's to stay within FSAE rules.


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PostPosted: Sun Oct 03, 2010 10:04 pm 
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So did it sound like a little V8? It looks like they got their own forging for the crank? Or is it maybe just a big hunk of steel stock?

One of those around 2 liters would be cool.

That home made transaxle really got my attention though. That would be cool, especially with a clutch. Then you could just put any motor in the front of a locost, no adapters.

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PostPosted: Mon Oct 04, 2010 2:57 am 
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Glen wrote:
a.moore wrote:


I got to see that in person in 99(?), I think they fired it up a couple times in the paddock, but the car never made it to the track that year. Oh and if anyone is wondering why you'd bother to do that and end up with such a small displacement, it's to stay within FSAE rules.


Yeah 600cc is max.

Also FSAE is also about engineering and development. I think there's awards on the techinical side too (stand to be corrected).


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PostPosted: Wed Oct 13, 2010 2:39 pm 
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pretty decent though mildly gratuitous autodesk presentation of a (HD, though its a very old design) split fork connecting rod/construct type crankshaft setup (plus i enjoy rage against the machine). with a change in the output shaft and the end plate to accept a thrust bearing, you could add a thruput clutch and with a bit more i think you could have a modular expandable platform. switching to watercooling, if desired would mean more design work but nothing that hasn't already been sussed out by the factory. you could change the bank angle a bit for fitment/nvh or to avoid copyright issues if needed. limited rpm range iirc but with modern stuff?? i could deal with ~200lb 2 liter v4 with 180 hp and a 7500 rpm redline(v4 version of an xb9). ..
http://www.youtube.com/watch?v=mj_Eo7llCOI

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PostPosted: Thu Oct 14, 2010 1:28 pm 
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BBlue wrote:
cheapracer, not trying to be argumentative, but if Aluminium is no lighter, why would anyone (at least OEM) mess with Aluminium for use in engine blocks? Aluminium introduces a lot headaches, expansion and warpage being obvious. Can that much be saved in machining time?

Bill


Cheaper in large scale manufacturing costs when all is considered such as tooling life and machining time. Remember that unlike before everyone now machines with high speed CNC machines with ceramic tools in some cases. Machining cast iron is quite a slow process in comparison but it didn't matter before because the machines and tool tips were slow.

Also better heat control and warm up time to meet pollution laws and in some European countries now it is law that 'X' % of the car has to be recyclable at the end of the cars life.

No headaches if you have the block and head of the same material and they are well on top of modern alloy mixes


Last edited by cheapracer on Thu Oct 14, 2010 1:33 pm, edited 1 time in total.

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PostPosted: Thu Oct 14, 2010 1:32 pm 
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move along, nothing to see here ....


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PostPosted: Sat Oct 30, 2010 6:37 pm 
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Anyone thought of working with an existing engine to build a Crower stroke engine?

http://en.wikipedia.org/wiki/Crower_six_stroke

I read an article about this a couple years ago, and then it dropped off the planet. The story is fascinating. Bruce Crower, of Crower Cams fame, 70 years old and retired, wakes up in the middle of the night from a dream, and has a single cylider prototype functioning by lunch. As of July 2009 they still had not awarded him a patent. A working prototype existed, and it should not be too hard to get there. The challenges are to adapt the principal to multiple pistons, and then overcome the challenges that water in the cylinder head would introduce. Since this is something that would be presumably used in home build vehicles as opposed to pruduction cars, we can bypass alot of emissions regulations and red tape. Theoretically, there is no limit to power or efficiency or RPM over any other 4 stroke, and once working, could be adapted to any engine. Jack might be interested in this for his MAX project too.

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PostPosted: Sat Oct 30, 2010 7:47 pm 
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hhmmmmm, sounds like you could put port injection on a direct injection motor then replace the gdi injectors with water injectors...... after that its a matter of reprogramming the ecu so it puts every other injection event thru the water injector once temperature is reached. maybe have an "unless throttle request is over xx%" command. pretty interrresting 8) nikasil liners, alloy pistons, ring materials? seems like it would run hot enough to not have much worry about much about condensation by programming the ecu to switch over to fuel only for xx seconds before shut down.
thar be things in the water though captain.....

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PostPosted: Sun Nov 07, 2010 1:44 am 
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Mustache81 wrote:
Anyone thought of working with an existing engine to build a Crower stroke engine?

http://en.wikipedia.org/wiki/Crower_six_stroke

I read an article about this a couple years ago, and then it dropped off the planet. The story is fascinating. Bruce Crower, of Crower Cams fame, 70 years old and retired, wakes up in the middle of the night from a dream, and has a single cylider prototype functioning by lunch. As of July 2009 they still had not awarded him a patent. A working prototype existed, and it should not be too hard to get there. The challenges are to adapt the principal to multiple pistons, and then overcome the challenges that water in the cylinder head would introduce. Since this is something that would be presumably used in home build vehicles as opposed to pruduction cars, we can bypass alot of emissions regulations and red tape. Theoretically, there is no limit to power or efficiency or RPM over any other 4 stroke, and once working, could be adapted to any engine. Jack might be interested in this for his MAX project too.


Yes, I want to try to stick one together next year if I have time. I will do what Crower did, take a diesel and lower the comp for petrol and use the diesel injector for the water. You need a camshaft of course to suit the 3 cycles, I'm sure Crower Cams have that info :). Need to know when to inject the water on the dead cycle as well. Crower did not take a patent on it leaving it free for the world by the way.

By the way, he did not have it "going by lunch", he made a number of prototypes searching for when the best time to inject the water in the cycle would be besides making a 3:1 reduction ratio and the special cam itself - makes for a nice myth though.


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PostPosted: Sun Nov 07, 2010 12:00 pm 
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cheapracer wrote:
Yes, I want to try to stick one together next year if I have time. I will do what Crower did, take a diesel and lower the comp for petrol and use the diesel injector for the water. You need a camshaft of course to suit the 3 cycles, I'm sure Crower Cams have that info :). Need to know when to inject the water on the dead cycle as well. Crower did not take a patent on it leaving it free for the world by the way.

i think you're making more work for yourself than you need to. why start with too high of a compression for example? thats just one more thing to overcome. .. if you plan on shutting off (port) fuel injectors during (di) water injection events you don't need to change the cam just be able to switch between injectors as appropriate. a megasquirt can handle that easily after proper programming (no different than using an existing injector emulator on a gaseous fuel system really) the steam expansion will provide more power than the compression stroke used, then it becomes a question of "is it enough of a return?". back to the days of steam for power output calculation formulae :P you would want some sort of demand based steam cycle shutoff of course, and probably a minimum engine temp for operation. .. corrosion of course will be an issue, as would minerals buildup.
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" You need a camshaft of course to suit the 3 cycles, I'm sure Crower Cams have that info :). "?

you don't honestly expect crower cams to give away currently unused intellectual property do you, i like open source but selling "the fruits of employee and owner labor" is how they make their money. ..
besides, what would you do with the "third cycle" when you aren't using the steam, such as during warmup, have power drains?

edit>> fyi people were adding a 2nd spark plug to their cylinder head long before gdi came about. .. its a common modification on older guzzi's. there's no reason that adding a positive action solenoid valve would be any harder.

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PostPosted: Sun Nov 07, 2010 12:36 pm 
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here's the basic formula for calculating how much heat is in the gas inside the cylinder after compression. this doesn't take into account the heat the block is holding that would also be applied to the water............

Attachment:
heat rise calc.png
heat rise calc.png [ 687 Bytes | Viewed 750 times ]


the wiki article is easier to understand that my 25 year old textbook.......
http://en.wikipedia.org/wiki/Adiabatic_process

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PostPosted: Sun Nov 07, 2010 12:57 pm 
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I find the Crower cycle to be especially interesting as I had the idea in the late '90's. But as I am not an engineer (mathematicly challenged) and computer stupid, I did nothing with it. Probably saved me what little sanity I had and thousands of dollars I didn't have.

It seems like it has limited potential for automotive use, but would be a killer idea in a stationary power plant where the required add ons would not be as significant.
Bill


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PostPosted: Sun Nov 07, 2010 1:17 pm 
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BBlue wrote:
I find the Crower cycle to be especially interesting as I had the idea in the late '90's. But as I am not an engineer (mathematicly challenged) and computer stupid, I did nothing with it. Probably saved me what little sanity I had and thousands of dollars I didn't have.

It seems like it has limited potential for automotive use, but would be a killer idea in a stationary power plant where the required add ons would not be as significant.
Bill

good thought!! we work on some (landfill) gas fueled generators that could be retrofitted to something like that very easily.
1.6mw rated inline compression ignition engine with ~65% of the energy lost as waste heat, makes me wonder how much could be recovered......
greeeatt now another idea to bubble away in the darkest recesses of my brain pan. :boxing:

:cheers:

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