Quiet Generator Box Build

[Darkspeed]

Im going to be building a quiet generator box and I had a few people ask me to document it, so im starting this thread for that, but you are welcome to comment.

This will take some time as I can only work on it part time at the moment..

Is it overkill? depends on what you dont like hearing.. or how good your hearing is..

I will be testing each step of the build with a USB Decibel meter.

I banged up a stainless Dry exhaust to replace the wet marine exhaust manifold and fitted the test muffler > Walker 21479 Quiet-Flow Stainless Steel Muffler

Muffler will eventually be remote mounted.

Two cooling circuits - Generator will have a remote mounted radiator and the box will have its own remote mounted radiator because it will be a sealed enclosure.

Honda Civic fan & 3 row performance aftermarket aluminum radiator ($60) for cooling the box (environmental heat trapped in the sealed box)

Same type radiator will be used for cooling the block except it will have a shroud and a Spal 30103202 12" Curved Blade Puller Fan.

The enclosure will be a box in box design like a soundproof room.

The bay will be partitioned and dampened to create the outer box and there will be an air gap between it and the inner box.

To service the generator you will have to slide out the inner box on its sliders and remove the cover to the inner box.

Generator is isolated from inner box by air springs mounted at 30 deg cradle configuration.

Outer box is isolated from inner box by low durometer rubber captured mounts.

Refrence > http://www.mh-audio.nl/acalculators.asp

Coolant line quick disconnects > Snap-tite 72 Series #16AN 1" 4GPM

Exhaust / air intake disconnect > Torctite Stainless Lap Joint Band Exhaust Clamp TTOEM200SS

Green Glue > http://www.greengluecompany.com/

Rubber mat > http://www.tractorsupply.com/tsc/product/rubber-mat-black-4-ft-x-6-ft?cm_vc=-10005

Dynamat Xtreme > http://www.dynamat.com/automotive-and-transportation/automotive-restoration/dynamat-xtreme/

Lead Sheet > http://www.rotometals.com/lead-sheet-and-shielding-s/31.htm

[Scott & Heather]

So cool. Todd you're contributing so much to the bus community in such a short time. Thanks for being awesome. How are you transferring the environment box heat to the remote radiator?

[Darkspeed]

So cool. Todd you're contributing so much to the bus community in such a short time. Thanks for being awesome. How are you transferring the environment box heat to the remote radiator?

Thanks Scott!

The block circuit will use the mechanical water pump to feed the external radiator.

There will be a radiator and puller fan inside the enclosure connected to an external radiator and puller fan. The little Honda racing radiators are awesome!

The box cooling circuit will be fed by a small electric water pump like a webasto pump or I have the option of using the accessory belt driven pump that is on the generator.

The accessory pump is a 3/4 pump that was originally to run coolant through the marine exhaust manifold - as this was a marine generator package.

[Scott & Heather]

Ok so for the enclosure radiator to radiator heat exchange...cool.

[RJ]

Todd -

You've left out a minor point:

Where in the chassis are you installing the genset?

FWIW & HTH. . .

 

[Darkspeed]

Todd -

You've left out a minor point:

Where in the chassis are you installing the genset?

FWIW & HTH. . .

 

Hi RJ, my current plan is to use the passenger side bay between the front wheel well and the diesel tank.

I am going to build a 36" slide out frame and attach the bay door to it so it slides out with the frame.

I will run the four coolant hoses across and back into the bay with the mesh door.

[RJ]

Todd -

Ok, the old HVAC service access bay, got it.  I know another 4106 owner who also used that bay for the genset, same fellow that used a 140hp Corvair muffler that he hung on the rear baggage bin bulkhead, exhausting out the passenger side wheelwell.  Unfortunately his coach was involved in an accident that totaled the bus, so it's now Coke cans. . .

When you stripped the coach, did you save the water pump which hung from the ceiling of that bay?  That pump is/was wired to the defroster fan circuit, it provided boost to the defrost heat exchanger when needed.

What else are you planning for the old A/C condenser compartment besides the genset radiators?

FWIW & HTH. . .

 

[TomC]

For remote radiator, that 12v fan will be noisy. I used a single inlet squirrel cage blower from Graingers belt driven with a 1/2hp 2spd totally enclosed fan cooled motor pulling air through the radiator exiting through the blower to the side of the bus. On high it cools to 117 degrees (hottest I've been in). On low, nearly silent night running.
To ventilate the enclosure, I use a 250cfm 8" inline bathroom ventilator also from Graingers. Good Luck, TomC

[luvrbus]

Yep you want a 3 speed 110v squirrel fan that only comes on with generator running,the folks I know with the 12v automotive fan seem to be always shut down here in the AZ heat 

[Darkspeed]

Good point about the exterior fan noise, its all about decibel vs cfm.

My limitation may be space but I will give it some thought.

I know because of the enclosure of a caged blower they in general radiate less sound.

The spal is my fall back because it will produce 1800cfm in a very small space and is very quiet at lower speeds, but I have not tested one at full tilt with the decibel meter.

Most generic automotive 12v fans are very noisy and highly inefficient.

Looks like most of the 1/2hp caged blowers have a comparable or greater cfm but they dont provide db specs so i may have to call dayton.

I also did not see 3 speed but they did have three phase which I could use with a VFD and have infinite speed control from a 4-20ma signal or depending on the type of single phase AC motor I could use a PWM.

Ok did some more research and found a 4 speed 115v Dayton that should work.

[TedCalvert]

Darkspeed;
 
Many VFDs will accept single-phase input, and give you 3-phase out.
Just curious, where you gonna get 4-20 mA?  Analog out card on a PLC or standalone controller?

Ted.

[Darkspeed]

Darkspeed;
 
Many VFDs will accept single-phase input, and give you 3-phase out.
Just curious, where you gonna get 4-20 mA?  Analog out card on a PLC or standalone controller?

Ted.

Hi Ted, true! I did some Hitachi single to three phase vfd's for machine motor controllers before.

I am doing a Direct Logic Productivity 2000 PLC for the bus with a C-more HMI in the dash. I built a lot of mobile automation systems around the DL260s with good results, even some canbus interface stuff.. Nothing like having your bus send you a text that it is too cold and wants to start the tank heaters or someone bumped it while you were away.

[Darkspeed]

Put my ear protection on and my respirator and spent some quality time with my generator running looking at what parts make the most noise.

1. Exhaust
2. Intake
3. valve train
4. Case
5. Output Alternator

The civic radiator seems to do a great job!

Things I need to solve..

I need to fireproof the exhaust manifold and enclosure bulkhead - combination of wet wrap and 2k  aluminum faced ceramic to keep heat in the exhaust until it leaves the box.

I need a simple way to disconnect the equipment outside the box so it can be slid out for service, or have all of the equipment slide out with the box.

Need to silence the intake - an engineer friend uses a stainless muffler for his generator intake, I have done the same on a compressor, may have to try that.


The OEM rubber mounts transmit a lot of noise and vibration into the steel workbench - but the are 27 years old so they may be a little stiff -

I found a perfect goodyear pneumatic spring that has a 2" installed height and a 580lb rating > 1S3-013

And a 4 speed 115v Dayton blower > 1XJY2 that will do 2000cfm and runs at 1100rpm so it should be fairly quiet.

I am thinking about putting a 200F automatic 50CF extinguisher in the outer box..just in case..

[RJ]

Todd -

Are your plans to run the exhaust to the rear axle and dump it out the passenger side?  If so, do what that other 4106 owner I know did and pick up a 140 hp Corvair muffler  (Walker #17908, $33 at O'Reilly's) and mount it on the rear bulkhead in front of the axle pumpkin between the brake pots.  Made his exhaust noise virtually non-existent.

FWIW & HTH. . .

 

[Darkspeed]

Thanks RJ, that is almost what I am using now, im using the walker quietflow on the exhaust (and possibly the intake) http://www.walkerexhaust.com/products/mufflers-muffler-assemblies/quiet-flow-ss it is very similar to what you suggested.

I have not decided where im exhausting yet, still trying to make all this fit in my reduced height bays safely.

BTW I got a chance to test one of the Fujitsu Ductless Mini-Split systems I want and the outdoor unit running on high was 43 dB   NINJA!

If anyone wants to learn about the proper use of materials, this is a good reference > http://www.sounddeadenershowdown.com/products

and....  https://books.google.com/books?id=AF_AYLaJNNIC&printsec=frontcover#v=onepage&q&f=false