Author Topic: forced induction & torque converter  (Read 37986 times)

Doug

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Re: forced induction & torque converter
« Reply #15 on: July 26, 2007, 07:48:49 PM »
HA, nothing cool bellow 7000, trust me I work there.

Its like shoveling coal at the gates of hell.......

Doug
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Doug

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Re: forced induction & torque converter
« Reply #16 on: July 27, 2007, 01:45:59 AM »
Phaedrus' thoughts: Of course the problem is a calculus problem - several interacting variables. But an ideal is not necessary. Clean air enters a pipe. The pipe is fairly straight and holds a constant cross section. Diameter is whatever's close to the as-built manifold - say 1 1/2 inch american standard sched 40. Start with a long pipe. Because the engine rocks as it fires an expansion joint is very desirable at the coupling to the head. Make up a plenum - a piece of 2" pipe, about a foot long with both ends closed and a pressure gauge to measure the internal pressure delta over atmosphereic pressure. open the pipe through a small tube, say 1/8 copper, to the intake valve area so that the slugs of air pressure will slowly average out in the plenum - so you can see what's "hitting" the valve. With engine running at design speed note pressure. shorten pipe, repeat. graph readings. when pressure is maximum you are there. This ought to get one close enough to "supercharge" 1 or 2 psi  This is opinion only, but that's how they scavenged some marine 2 stroke ship engines in the 1920's - it ought to work well enough. I would start with a 20 foot length of pipe set up on saw horses and just cut away, but a guy could do some research and maybe find some formulas for a rough idea of pipe length. These are related to the formulas contained in utterpower cd on exhaust muffler design. Exhaust pulses can, in theory, be used to augment this process, but there's a lot more to fiddle and possibly some corrosion or carbon problems too.

You have me thinking now about intake and exhaust upgrades fro better performance.

I found a good PDF file but lost the URL for others to read.

Seems to me that this might be a much better idea than we previously thought since we are all looking to improve the engines with better exhaust and airfilters that some of this kind of thinking be used to make sure we build as free flowing with constipation.....

Me thinks a runner in the 5 to 8 foot range ( 1300 rpm petteroid ) might be enough to catch the second pulse and since we are mainly concerned with a fixed rpm we can look at exhaust runner lenthg as well tp try and scavange as much as possible.
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phaedrus

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Re: forced induction & torque converter
« Reply #17 on: July 27, 2007, 02:19:46 PM »
Does anybody have any solid idea how much power the 6-1 uses to run itself? Let me make the question clear - suppose there's zero fuel injected and the engine is "running" at about 650 revs - being driven by an electric motor. Assume 100% efficiency electric motor and coupling to the 6-1. To simulate the power usage of the injector pump we'll attach an injector that sprays into a can. How much power would this engine take?

I would guess the number at about 750 watts, but I'd sure like to have some hard data..

My hunch is that's about how much power can be "added" to the 6-1 by careful tuning of intake and exhaust. Understand the idea's not to make more power by using more fuel, instead it's to waste less power pumping gasses by letting the natural frequency of events do the pumping instead of the piston. Going over 6 hp at 650 revs seems to be dangerous, based on my observation of my engine. This tactic does not go over 6 hp - it just moves indicated power from wasted to usable.
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Doug

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Re: forced induction & torque converter
« Reply #18 on: July 27, 2007, 05:50:57 PM »
Well if we produce 30% shaft power from the conversion of fuel to work, and we know we loose about 30% to cooling system heat whats left are parasite loads and exhaust heat. Thats as far as I can go...
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phaedrus

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Re: forced induction & torque converter
« Reply #19 on: July 27, 2007, 10:17:09 PM »
Banks says (http://www.bankspower.com/Tech_todaysdiesel.cfm), in part, that most of the pumping loss in diesels is in the exhaust phase. Taking advantage of the exhaust pulse could eliminate much or all of this loss. Though intake pumping loss is minor, tuned intake could (maybe) create a minor "extra power stroke" if the momentary air pressure on intake was higher than atmosphere.

Tuned intake and exhaust would require silencers, at least in my location. But it looks like a free ride to the "tune" of something like, perhaps, one whole horsepower.
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Bluecometk

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Re: forced induction & torque converter
« Reply #20 on: July 27, 2007, 11:41:59 PM »
  I am not an engineer by any means but I think with all due respect that your estimates of HP
 gain are high for intake work. I work for a vehicle manufacturer and yes I realize gas engines
 and diesels are different beasts, but I know for a fact that manufacturers of vehicles will spend
 hundreds of thousands of dollars and thousands of man hours on a flow bench or wind tunnel
 for a 1 HP gain. Granted those engines are further down the volumetric efficiency chain and
 harder to make a significant gain.Even though the Lister is a slow speed engine I think it still
 plays by the same rules . I think you would get much greater results if you just did a plain old
port match and valve bowl blend. From just listening to the caliper of post on the board I think
 that most if not all could do the job quite well. I have seen gains of 70+HP on NA 300 HP
 engines with a full port, bowl job. Go into the combustion chamber and work on it and your
talking another 20Hp gain.I think a 20% HP gain would not be out of the question. 
« Last Edit: July 27, 2007, 11:47:41 PM by Bluecometk »
Bluecometk

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Doug

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Re: forced induction & torque converter
« Reply #21 on: July 28, 2007, 01:03:03 AM »
Well my ports are now as matched and open as possible.

I never bothered to try and grind any material because the shape was designed to make as much turblance as possible and any modifications would probably not enhance this.

Considered a turbo but I realy don't need more power, but an engine gas or diesel is a pump so anything that makes that pump function better is a step forward.

The next logical step is to look at how the intake runner and exhaust are set and find the optimum lengths, a good large free flow exhaust that will also control noise ( probably a large underground expansion chamber like a 45 gallon drum ).

Extra power to feed a surge would be nice and seems to mne the factory intakes and exhaust are a major bottle neck we have not adressed. We all have excess fuel capacity  so a minor improvement in VE and perhaps a little boost from a ram tube might put some of this black smoke back to work...
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phaedrus

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Re: forced induction & torque converter
« Reply #22 on: July 28, 2007, 01:20:24 AM »
estimates are estimates....but comparison to a variable speed petrol engine is...  Well those engine are a whole nuther thang.

750 watts estimate is what...something like 18% ?

 Let us try something and assume a 2 psi "boost" at intake and a 2 psi "vacuum"i at exhaust - nevermind feeding more fuel. If it was "running" just on that delta at 650 revs how much power would be produced at the piston? That ought to give a very rough "gestimate"

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Doug

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Re: forced induction & torque converter
« Reply #23 on: July 28, 2007, 03:08:01 AM »
I made this....

http://www.putfile.com/pic.php?img=4924460

Time to make an 8 foot long adapter for it I guess

Thank you phaedrus for making me think in new directions

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mike90045

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Re: forced induction & torque converter
« Reply #24 on: July 28, 2007, 03:47:20 AM »
Does anybody have any solid idea how much power the 6-1 uses to run itself?

Someone here did a balance test with the head off, and a 1/2 HP motor was not quite able to spin it up to 650 RPM  His guess was 3/4 horse would do it.

http://listerengine.com/smf/index.php?topic=1882.msg24434#msg24434

phaedrus

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Re: forced induction & torque converter
« Reply #25 on: July 28, 2007, 12:18:04 PM »
Doug, that's a very kind remark, thank you!

Mike, that's comforting about the motor driving the machine - if one were to add the pumping losses it looks like my shootfromthehip 750 watts guess just might be close. Thanks!

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phaedrus

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Re: forced induction & torque converter
« Reply #26 on: July 28, 2007, 03:55:00 PM »
http://en.wikipedia.org/wiki/Helmholtz_resonance   (has the math for design)

I've been thinking about how to tune the exhaust - the intake's easy because there is a fairly stable temperature there, but the exhaust's more interesting. Does it make more sense to tune for maximum output, where the exhaust temperature will be quite high, or for economy at a modest load with lower temperatures? Is it possible to design a system with two "nodes" so that one could have both? There seems to be more to gain in the exhaust area.
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Doug

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Re: forced induction & torque converter
« Reply #27 on: July 29, 2007, 01:00:23 AM »
I would think you would like to design for max power.

At lower power less scavanging would leave more exhaust left behind and this would dilute the fresh charge with a warm inert gas.

Nox production is an exothermic reaction ( requires heat ) that steals power so that small EGR effect wouldn't hurt and might even help a tad.

Just theorectical guess work on my part....

Doug
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GuyFawkes

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Re: forced induction & torque converter
« Reply #28 on: July 29, 2007, 07:46:22 AM »
NOx production is a byproduct of high temperatures, to minimise NOx production you are really cutting the mechanical efficiency of the motor...

As far as charge tuning goes, the CS has relatively slow piston speeds (easy to work out with a bit of math mean and peak piston speed) and relatively low mean and peak gas induction speeds...

Tuning intake and exhaust works better at higher gas speeds, think japanese 2 stroke motorcycles, put a spanny chamber on the exhaust and at the right rpm range (don't forget piston valve 2 stroke = wads of valve overlap too) you can actually suck intake air in with the exhaust gases...

With a CS there is bugger all valve overlap, any gains you get are going to be marginal, and probably more than eaten up by the system providing them, eg intercoolers etc... with minimal valve overlap etc a long induction pipe can actually end up restricting intake flow...

personally if I was at altitude I'd use an centrifugal fan direct coupled to the crankshaft and supercharge a couple of psi that way, probably the most bang for your buck, lowest tech for reliability, and easy and cheap to do.

don't forget diesel is not stochastic, at less that full rack / power fuel air ratio is way low, so high altitude only limits peak BHP, even at constant RPM, which is an air pumping problem...

say for example at 10k feet you can only get 4 BHP, not 6, the simple solution is run a CS 8/1, eg 150 extra RPM, this changes your gearing requirements if driving an AC head and requiring a fixed frequency, but remember that in out example at 10k feet you 8/1 is only producing the same power as a 6/1 at sea level, eg it ain't working flat out.

Basically this whole problem falls neatly into the peak vs average demand problem, my original start-o-matic is rated at 2.5 KVA @ 50 Hz and 240 VAC from a 6/1, so it will produce 2.5 x 24 = 60 kWh in 24 hours, about 3 to 4 time my daily needs (guesstimating)

from this perspective, your actual problem lies in the area of peak vs average demand, yet you are looking for solutions in the wrong area, by tweaking the motor, so your solutions will never be optimal...

we used to get this ALL THE TIME on the boats, owners would size the genny to run the AC, battery chargers, lights, boil a kettle and run the cooker, so you'd get 50 foot boats with 17 or 20 kw gen sets, which meant buying 2 pole 3000 rpm units (small and compact to actually fit in the engine room, plus cheap per kw rating) which spent most of their lives running at 25% capacity of less, which meant they wore out quick and starting burning oil quicker....

DC is every bit as good as AC for everything except running synchronous rotating machinery, water heaters and bar fires work fine on DC, as do lights, and there is nothing in a washing machine that requires that the drum be driven by an AC motor, etc etc etc.....

MAny years ago I converted a washing machine from AC to DC motor power, and in doing so by passed all the programme electronics, so DC powered the heating elements, and DC powered the drum motor, necessity forced this on me at the time, DC was available in abundance and a DC servo motor was available..... you'd thing cuttiing out all the rotate clockwise for ten revolutions, pause for ten seconds then rotate anticlockwise for ten revolutions, programming with "flip the switch to start the drum, then reverse it when you pass by 20 minutes later" would utterly destroy the effectiveness of the washing machine, at least, that's what all the washing machine adverts would have you believe, fact is nobody could tell the difference, and I mean nobody.

"WHEN THE SHIT HITS THE FAN" scenarios, the last thing you want is 21st century crap powered by a 19th century diesel, it don't make sense and it ain't sutainable.

In the same way that the CS is simple, gut a washing machine of everything except the drum, run DC through the heating elements and a DC servo motor to spin the drum and you have something that will do EXACTLY the same job, JUST AS WELL, but you can fix that sucker if need be.

that is one notably lacking thing I see, survival types running generators that are 100% dependent of 2 cent electronic components, the analogy here is the modern auto / truck alternator vs the old dynamo and regulator, the dyno and reg you could fix, and I never saw anyone moaning about the lack of output from a basic 22 amp lucas dynamo longer than it took to go to the shop and fit a 50 amp dynamo, which was of course 110% electrically compatible with everything else, but oh no, we got marketed into the cheaper to make, disposable alternator, just like we got marketed into points instead of magneto because it was cheaper to make, but marketed as being superior....

back when I was running dynamo and magneto bikes (BSA A10) one of the top UK Honda bods was down at the new local Honda dealership going on about this stuff, I said "bollocks" he started to explain to poor stupid deluded me why he was right, I pulled a plug lead off the demo CBX (it was a new bike then) pulled a spare plug from my pack and hit the ignition while holding it, said "ow", and got him to do the same, then got him to hold it (first, I ain't stupid) while connected to one of the BSA HT leads, fucker dropped it like he'd been hit in the elbow with a pickaxe handle... I heard later that after I'd left he started using that as an example of why electronic ignition was superior, it was apparently "safer"..... bullshitting bastards the lot of them.

there is a moral here, the SOLE PURPOSE of making thinks like washing machines so complex is to place them beyond your reach, technologically, so they can control the source and implement new versions at will, the ACTUAL JOB done is no different....

A 5000 dollar programmable fancy oven doesn't cook sunday lunch or boil water for coffee ANY BETTER than a solid fuel Aga
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M61hops

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Re: forced induction & torque converter
« Reply #29 on: July 29, 2007, 08:42:58 AM »
Sometimes, I do like the way you think Guy.  Glad you came back.                                Leland
I pray everyday giving thanks that I have one of the "fun" mental disorders!