Hiding a powerplant in a residential neighborhood?

[sailawayrb]

Re the earlier discussion on exhaust plumes .... I checked my exhaust temperature and it is just noticeable to the touch (hand in exhaust stream) so it is well above ambient (currently about 8C)
I am also running more than 2 times of the standard listeroid power at about 16-18 hp.

I am also not at maximum exhaust temperature yet (but I do have my plume of about 30 ft)

That makes sense and likely explains our different results.  I can't claim credit that I intentionally designed the heat transfer characteristics of my setup.  It just worked out that way given the lay of my land and what I had to do.

Bob B.

[carbon-rod]

I have exactly the same predicament Bio, did you get your system installed and silenced?

I live on an even smaller block 650m2, the neighbours are right on our boundary so I will too need to work on some underground pipes to silence things. I like the idea of the underground system you installed Bob, I was thinking of installing a concrete soak-well and then having a 4 inch pvc pipe coming off that and running up the side of my shed mimmicing a down pipe. I could actually use it as the downpipe soak-well come to think of it, if a bit of water is in the soak-well at the time then maybe that will help reduce any smell (I am planning to run it on WVO), I guess unfortunately for you having to hide WMO seems like a harder task, would bubbling it through water reduce the smell somewhat possibly?

[veggie]

This is how one fellow controlled his generator noise in a residential area.
Perhaps good for small generators.

http://www.youtube.com/watch?v=62-mNynTa0M

veggie

[Ronmar]

As I see it, you have 5 issues.
1. Mechanical vibration.  The slow singles don't make much noise, but they do make vibration in that big power stroke.  I am in the large mass camp.  Pour a concrete block(3/4 ton +) to bolt it to. Force = mass times acceleration.  The larger the mass, the larger the force required to accelerate it.  Then place that large mass and engine on rubber horse stall mats or some other flexible barrier to isolate that mass from the earth.  This is how mine is mounted, 1300# block of concrete on 1/2" stall matt and I can just feel mine running in my living room about 35' away.

2.  Exhaust thump.  A large buffered expansion chamber pretty much takes care of this.  Underground concrete cistern is a good effective example of this, but I believe you can be almost as effective with conventional mufflers, they just need to have a large enough volume to absorb the exhaust pulse completely. The first thing I hear walking up my driveway with the generator running is the exhaust thump from my open shed door bouncing off garage and barn, from the stock peppercan muffler.  dig a hole a little larger than a 55 gallon barrel.  pour a little concrete in to the bottom and set barrel in on top of wet crete.  fill hole outside of barrel with concrete.  if barrel rots out, it is still backed by concrete...  dig a shallow round hole several inches deep and line with plastic, fill half full of crete, add reenforcement mesh and fill remainder of hole to cast lid for tank so someone in the future wont fall thru it.  Add PVC pipe sections to cast inlet/outlet holes(or thru the sides of he drum if desired).  

3.  Intake noise.  Again, automotive mufflers or air compressor silencers will dampen this noise, as would the enclosure mentioned in 4 below.

4.  Valve train noise/clatter.  Not a lot on a roid, but an insulated building will take care of most of it.  A building inside a building would be ideal as it would allow an air/noise lock to not give the noise away when you enter or leave the "tool" shed.

5.  Smell.  Mine makes no visible exhaust unless I pass above 3KW of load.  It does smell like a diesel though.  As high as possible an outlet would be my advice.  Perhaps another plumbing vent or two in your roof to disperse the exhaust.  Exhaust temp is going to typically be higher than ambient, so if you start high, it should only go up from there, and the higher it gets, the farther away it gets before possibly being blown back down where someone can smell it.  

Having run both now, the vibration thump of a listeroid is difficult, but IMO, the roid is easier overall than a chinese horizontal.  My S1100 is LOUD!

[carbon-rod]

Hey Ronmar,

when it comes to the power stroke if the engine is well balanced would it still have much impact? I have seen some clips of engines on wheel-able carts and the tyres are barely compressing during operation, it is soo smooth!

I might even have two expansion champbers next to each other underground (they will double up as drainage pits... and the exhaust can pass through one and into the other and then out of a large pipe through the top... if that doesn't work effectively at least I have 2 new drainage pits

I think I will build an enclosure which can drop over top of the engine and put some fibre glass or sound proofing material in that... I think 50% of the project will be spent trying to make the thing invisible...

[Ronmar]

I spent a considerable ammount of time and effort balancing my engine.  I put the metal frame up on 3/4" pipe rollers on smooth concrete so you could push the 1/2 ton of engine/generator/frame easilly with a fingertip.  Mine will run UNDER LOAD like that unrestrained with only about .015" of movement on the rollers.  What you feel in your feet is not from out of balance, but an out of balance condition can make it seem worse. 

For every action there is an equal and opposite reaction.  These engines have a MASSIVE torque pulse, enough in a fraction of a second and less than 180 degrees of crank rotation to accelerate and store enough energy in the flywheels to maintain RPM, power the process itself and still perform 4.4KW/6HP of average mechanical energy output over the remaining 540 degrees of the cycle.  It is the opposite reaction to this torque pulse that you feel thru your toes... I lift the fuel and decompressor levers and I don't feel anything as it coasts to a stop...   

[carbon-rod]

hmm I think your spot on with your conclusion of the thumping....  is your metal engine mounting frame directly mounted to the concrete? have you experimented with a floating arrangement before on rubber of some type and if so did it help? I dare say the rubber would require replacing every so often but for me it might be a worthwhile exercise if it prevents the transfer of the thud. what do you think?

[Carlb]

I have my steel I beam frame sitting on a 1"thick rubber mat which is bolted to 2 8x8 pieces of timber. The 8x8 sit on another 1" thick piece of rubber.  The timber is not bolted to the floor but i do have angle iron bolted to the floor in front and back as well as the sides of the 8x8's with a piece of rubber between them and the timber. This is sitting on a normal concrete garage floor.  You can not feel the thumping if you are more than 4 feet away from the engine.   My exhaust goes into an old propane tank then a large straight flow muffler to the outside where it then goes into a length of 4" PVC.  You can not hear it running 30 feet away if the load is 2400 watts or less and even fully loaded it is quite quiet.

here is a link to it running.
http://www.youtube.com/watch?v=UfGjlHNX-68

The exhaust has been changed since this video was shot.

[vdubnut62]

I mounted 4 cheap wheel/tires from TSC on my S1100 outfit, REALLY helped quiet it down.  Best $20 I spent on it.
Ron.

[Ronmar]

I mounted 4 cheap wheel/tires from TSC on my S1100 outfit, REALLY helped quiet it down.  Best $20 I spent on it.
Ron.

I slid a couple of 2" thick blocks of high density ethyfoam under the frame on my Changchai and it is a whole different animal.  Still noisy, but it dosn't appear to move and I cannot feel it in my feet standing on the concrete floor right next to it.

[carbon-rod]

Ahh excellent, well I guess I will be building it on a movable cart with some blow up wheels! that's a great idea to stop the thud from transferring into the ground, The blow up tyres provide a pretty good air cushion compared to the solid rubber I guess..

Are the intakes particularly noisy? I think I will just incorporate a common air filter from a car over here, that should provide a decent reduction of intake noise, or do you think I should go with something specifically designed to reduce intake noise?

[dieselgman]

Intake noise too loud? I suppose that answer depends on how much noise you can tolerate! Lister actually supplied intake silencers for some of their product line, think small compartments on-board a sailboat! They do tend to be a bit noisy!

dieselgman

[vdubnut62]

Are the intakes particularly noisy? I think I will just incorporate a common air filter from a car over here, that should provide a decent reduction of intake noise, or do you think I should go with something specifically designed to reduce intake noise?

I have no idea , I have never been able to hear mine over the rest of the knocking and thrashing.
I still think it sounds like half a 55 gallon drum of hammers rolling downhill.
Ron

[carbon-rod]

haha vbnut you're making me a bit scared!

To me I don't care about the sound, I would love to have the engine run all day and lister to it's heartbeat, the issue is neighbours. My block is just over 600sqm and right up against 2 other neighbours so it needs to be nice and quiet so I can run it for long periods without them noticing...

[XYZER]

Are the intakes particularly noisy? I think I will just incorporate a common air filter from a car over here, that should provide a decent reduction of intake noise, or do you think I should go with something specifically designed to reduce intake noise?

Some Indian clones are noisy some not.......IMO it depends on the guy locating the cam lobes when they are drilled and pinned. I have 2 6/1's. The first is very quiet on the intake. I never have had any issue with intake noise. Then I bought a 2nd 6/1 and I could not figure out the obnoxious sound it made.....finally I discovered it was the intake. At the same time others were complaining of this issue. Most of us went with the intake silencer/filter I believe they use on air compressors from McMaster Carr. It helped considerably. I set my cam timing by when the intake valve opens at 6 deg (memory) BTC on my quiet 6/1. I never could get the noisy one to time correctly. It was always off ½ deg or so. I believe the cam is incorrectly assembled on a noisy intake 6/1.