Where to find guidelines for building generator compartment?

[luvrbus]

All the generators with the factory quite box the suction is on the bottom ,the generator has fan between the engine and the head that needs fresh air also sucking from the bottom helps with noise level.I relocated my air cleaner with another 90 bend and dropped my DB from 58 to 51 dba

[luvrbus]

Geez, that's a new one - no diesel powered hydronics allowed? Hummm.. need to sort out how to stay warm in the winter in one of these places, maybe, just stay elsewhere.

The only electric in my water circulation system is the hot water heater and I think it is plumbed into the hydro heating system, primarily to heat the hot water and engine block. It is a lot less powerful than the Webasto but in an emergency it could work on a couple radiators if I redirect the flow to them. A couple electric space heaters would work too.

The EGT (exhaust Temp) on those are around 600F they will start a fire .I saw a guy at Bus'n USA park his car in front of his and it melted the plastic bumper ,they limit the length on the exhaust to get rid of the heat my manual says 47 inches max   

[belfert]

All the generators with the factory quite box the suction is on the bottom ,the generator has fan between the engine and the head that needs fresh air also sucking from the bottom helps with noise level.I relocated my air cleaner with another 90 bend and dropped my DB from 58 to 51 dba

Interesting.  My current Powertech blows out the bottom and air for the radiator come from the side.  Justin from WRICO said he suspects my Powertech generator if run at full load in high temps would overheat just due to not enough airflow.  I have run it in 107 degrees at 4,000 feet without overheating and I had a fair bit running on it.

[richard5933]

All the generators with the factory quite box the suction is on the bottom ,the generator has fan between the engine and the head that needs fresh air also sucking from the bottom helps with noise level.I relocated my air cleaner with another 90 bend and dropped my DB from 58 to 51 dba

Are you talking about the Onan QD generators?

I don't doubt what you're saying about them all drawing from the bottom, but that still leaves the question of why? I'd first have to know if it's for convenience of manufacture or if it's truly the best location to place the intake for cooling performance.

What I mean is, many of the units that come with factory quiet boxes are built to be somewhat universal and suitable for installation in a variety of coaches. Nearly every coach will have access for intake air from the bottom, either through the floor of the bay or by being installed in a bay without a floor.

If they had the intake on the side of a factory-built unit, it would require custom intake ducting built for each unique type of install. For us doing conversions that would be okay, but not for a manufacturer hoping to install the same genset in a variety of models.

Also, many of the coaches being built with factory quiet boxes have fiberglass/plastic on the sides. Not sure but would suspect that it makes for a cleaner look for high-end coaches to leave the intake venting on the bottom rather than cutting into the siding.

[belfert]

I talked to Justin at WRICO again and he said the air doesn't have to come from below for the radiator for sure, and probably not for the generator compartment either.

As far as enclosed diesel generators for motorhomes, is anybody using anything besides Powertech or Cummins Onan?  It seemed like for a time a lot of motorhomes had the Powertech enclosed generators.  Overall, Cummins Onan is much bigger in the market.
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[luvrbus]

I had a 20kw ESP generator in a quite box it was vented from the bottom never caused a problem,the Onan the generator radiator is layed flat in the bottom of the enclose case it does blow a lot of dust on gravel roads I don't care for that but it never overheats or shuts down even at 127F heat this summer

[Busted Knuckle]

I had a 20kw ESP generator in a quite box it was vented from the bottom never caused a problem,the Onan the generator radiator is layed flat in the bottom of the enclose case it does blow a lot of dust on gravel roads I don't care for that but it never overheats or shuts down even at 127F heat this summer

Clifford I learned a trick for that from a friend that ran a fleet of MCI's he took a mud flap and used angle iron and a piece of flat stock to pinch it on both ends then hung the ends on 3 small chains per end under the blowers about 5-6" below the bus, his buses were always nice an shiney and his drivers never had to turn off the A/C on gravel roads an parking lots like a bunch of us had too! (until I learned this trick too!)
  BK 

[buswarrior]

Lots of MCI with the flap under the AC discharge.

Might be a factory option?

A good consideration for the bottom discharge generator crowd too.

Happy coaching!
Buswarrior

[6805eagleguy]

That sounds like a good idea might have to implement,
I have bottom discharge

[belfert]

The bottom flap must be a factory option on MCI coaches as I have seen a lot of them over the years.  I had no idea what it is for before this thread.

[Jim Blackwood]

I'd love to see a picture of that.

Jim

[Busted Knuckle]

I don't think it was a factory option as much as once seen many owners/shops copied it.
I never saw one from the factory, but it's easy to do. I don't have any pics, but I copied the ones Bill had done and it worked out nicely. I had other drivers getting down on their hands and knees taking pics of mine to show their mechanics so they didn't have to turn their A/C off in dusty parking lots!
  BK 

[Paso One]

The first picture is whats on a 88 102 A 3 the second picture is a 96 102 D3

[Jim Blackwood]

Can't quite visualize it. What keeps the flap from dragging the ground?

On the noise cancellation, If you can lay your hands on an audio spectrum analyzer (Hi-Fi hobbyists often have them, or they can be found pretty cheap online) you can isolate the loudest frequency or the most annoying one. Take the center frequency, divide into 1 and multiply by the rate of sound propagation (6xx mph I think) and you can get the wavelength. There are online calculators that can do this for you. Take one quarter that distance and that is what you need for your sound trap. This is a dead end stub coming off the corner of a 90 degree bend and in a straight line with the source of the noise. Car makers do this all the time in intake systems. If you have more than one frequency to cancel out you can step the reflecting wall to different lengths.

Think of a sine wave. One wavelength is a full cycle including top and bottom. From your bend it takes 1/4 wave to hit the reflecting wall and 1/4 wave to get back, putting the reflected wave exactly 180 degrees out of phase and cancelling the incoming wave. That's how passive noise cancellation works. It's also known as a 1/4 wave trap. The distances required should make it quite feasible to build and it can almost completely cancel out the tuned frequency.

Jim

[buswarrior]

The flap is attached at both ends, and droops in the middle.

Typically with a link or two of chain, air can get out all the way around, but not blast straight down.

Happy coaching!
Buswarrior