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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Brian Diehl on August 27, 2007, 11:42:02 AM



Title: Electric Fan or hydraulic motor
Post by: Brian Diehl on August 27, 2007, 11:42:02 AM
My ISM re-power is working great now that I have most of the fine tuning done.  The one area I'm not totally happy about is the cooling system.  I used the original blower driven off the crankshaft.  I know by how cool the motor runs that I have a lot of excess cooling capacity and am wasting horsepower/diesel by using the system as it is now.

I'm thinking about using an electric fan to pull air through my radiators/CAC on my ISM re-power instead.  Do you guys have any good sources I can use to get a couple (2) electric fans?  Considering how cool my installation runs I'm thinking I could be happier with an electric setup than always pulling air through and on to the engine. 

Alternatively, maybe a hydraulic motor in place of the blower box would work if I could turn the motor on and off with a relay.  Any ideas on a reasonable double shafted/taper shafted hydraulic motor?  I would prefer a multiple speed motor controller if at all possible. 


Title: Re: Electric Fan or hydraulic motor
Post by: H3Jim on August 27, 2007, 12:03:51 PM
How about the same setup you have now, but add an electric fan clutch that is actuated by temp.  Best of both worlds, lots of cooling pwer, but no waste of enging power.


Title: Re: Electric Fan or hydraulic motor
Post by: kyle4501 on August 27, 2007, 12:28:17 PM
You can reduce the HP required by the fan by reducing the amount of air it moves.
You can do this by putting a smaller pulley on the crank or a larger pulley on the fan.

Cheaper still is to damper the inlet or outlet of the fan. You could do this by putting one of those cold weather covers on your radiator like the big trucks do. Easy to adjust for current conditions too.


Usually, the electric fans that will last in this type of application are quite expensive & electric power hogs that may require a larger alternator.

Glad things are working out  ;D


Title: Re: Electric Fan or hydraulic motor
Post by: rv_safetyman on August 27, 2007, 12:31:36 PM
Hi Brian.  You must not recall the "famous" thread on BNO that involved Two Dogs a few years ago.  That was the thread of all threads.  Basic conclusion is that electric fans will not do the job. 

I have a photo of an MCI where the person appears to have installed heating fan motors from a bus (motors must be several HP and maybe 12-14 inches in diameter).  Did not hear how that worked.

On my Eagle, I have an air clutch fan hub drivng a large plastic type truck fan (can't use the heavy Eagle fan as I am sure it would tear up the clutch with the big inertia).  I tried hooking it up to the Series 60 control system, but for some reason it does not trigger the fan.  I now have it hooked up to a switch on the dash (controls the Series 60 air valve). 

I find that the fan must be on most of the time.  I sometimes turn it off when it is cold outside (less than 40), but even there it will start to get hot on big hills. 

When you consider that the fan draws maybe 15 HP (guess) and the bus takes maybe 200 HP at 70 (wild axx guess), I don't think you would ever see it in fuel mileage. 

Jim


Title: Re: Electric Fan or hydraulic motor
Post by: Brian Diehl on August 27, 2007, 12:43:20 PM
How about the same setup you have now, but add an electric fan clutch that is actuated by temp.  Best of both worlds, lots of cooling pwer, but no waste of enging power.

I may be imagination limited here, but I can't figure out how to modify the existing blower box/pulley to accept a clutch.  Any ideas?


Title: Re: Electric Fan or hydraulic motor
Post by: Brian Diehl on August 27, 2007, 12:48:07 PM

Cheaper still is to damper the inlet or outlet of the fan. You could do this by putting one of those cold weather covers on your radiator like the big trucks do. Easy to adjust for current conditions too.

Glad things are working out  ;D

The MCI blower draws air in thru a round inlet and then dumps it out a square opening down on to the engine.  I don't understand how vacuum and air flow affect horse power so forgive me if this question is stupid.  If I were to put a restrictor plate over the inlet to reduce the opening size I would reduce the amount of air flow.  How or would this reduce the hp required to run the fan?  Wouldn't the vacuum effect cause more HP to be used instead of less?


Title: Re: Electric Fan or hydraulic motor
Post by: DavidInWilmNC on August 27, 2007, 01:21:39 PM
The MCI blower draws air in thru a round inlet and then dumps it out a square opening down on to the engine.  I don't understand how vacuum and air flow affect horse power so forgive me if this question is stupid.  If I were to put a restrictor plate over the inlet to reduce the opening size I would reduce the amount of air flow.  How or would this reduce the hp required to run the fan?  Wouldn't the vacuum effect cause more HP to be used instead of less?

Brian,

Find a small squirrel cage / centrifugal blower.  Run it with inlets and outlets open.  Then, slightly cover the inlet.  You'll hear the motor speed up.  That's 'cause it's moving less air.  Less air being moved = less power needed.  I like the idea of a damper or plate that could be used to partially cover the air inlet on the blower. 

David


Title: Re: Electric Fan or hydraulic motor
Post by: kyle4501 on August 27, 2007, 01:59:08 PM
The MCI blower draws air in thru a round inlet and then dumps it out a square opening down on to the engine.  I don't understand how vacuum and air flow affect horse power so forgive me if this question is stupid.  If I were to put a restrictor plate over the inlet to reduce the opening size I would reduce the amount of air flow.  How or would this reduce the hp required to run the fan?  Wouldn't the vacuum effect cause more HP to be used instead of less?

Brian, the required HP is a result of mass of fluid moved & pressure differential.

Most of our intuition comes from pumping incompressible fluids. If you were pumping oil & blocked off the outlet, yes HP would increase because you are building pressure.

However, with a centrifugal fan & Air (which is highly compressible) , our intuition fails us.

Sorry I can't explain it better.


Title: Re: Electric Fan or hydraulic motor
Post by: Brian Diehl on August 27, 2007, 02:34:10 PM
So, given this thread I'm starting to lean more towards an inlet restriction that is controllable/variable.  I'll have to give this some thought on how to make it variable, reliable, and easy to construct/maintain.  Any ideas?


Title: Re: Electric Fan or hydraulic motor
Post by: tekebird on August 27, 2007, 02:54:57 PM
doesn't your bus have shutters at the radiator and shutter doors on each of the blowers?



Title: Re: Electric Fan or hydraulic motor
Post by: Len Silva on August 27, 2007, 02:57:24 PM
The simplest method may well be shutterstat technology from 50 years ago.  I think they were opened or closed depending on temperature (rather than variable) but might be workable for you.

Len


Title: Re: Electric Fan or hydraulic motor
Post by: Brian Diehl on August 27, 2007, 03:46:54 PM
doesn't your bus have shutters at the radiator and shutter doors on each of the blowers?



I had shutters until I mounted the intercoolers in front of the radiators!  :-)


Title: Re: Electric Fan or hydraulic motor
Post by: kyle4501 on August 27, 2007, 04:30:34 PM
Look at how the big trucks cover their radiators. Maybe you can get a trim shop to sew you some external covers that snap on (like pickup bed covers). Maybe have a couple different sizes made for differing conditions.

Maybe you make some metal covers - Hey, Chaz may be ready to work with some metal for a change after what he's been working on lately.  ;D


Title: Re: Electric Fan or hydraulic motor
Post by: buswarrior on August 27, 2007, 04:54:42 PM
Hello Brian.

Re-install the dampers in the outlets, and the temp control into the rad pipe as per stock install. Lots of southern busnuts will give you their take-outs if you tossed yours.

Rebuild the damper controls to be sure they are strong on the re-tract.

You have no thermostats in that engine?

With no ram air in a rear engine bus for the rad, the fan will have to pull at least some air all the time even for your relatively cooler running 4 stroke.

happy coaching!
buswarrior


Title: Re: Electric Fan or hydraulic motor
Post by: Sam 4106 on August 27, 2007, 05:46:06 PM
Hi Brian,
I hate to put a damper (pun intended) on your solution of restricting the air flow through your radiators. But, if you restrict the air flow through the radiators you will also be reducing the air flow through your intercoolers, thus taking less heat out of your combustion air. What effect will that have on your engine efficiency? Perhaps none, but it may be worth some thought. Why aren't your thermostat(s) keeping your engine at the correct temperature? It seems to me that if your thermostat(s) are doing their job you would have proper operating temperature.
Another thought I have is, would you have enough cooling with just one radiator? Or, if not, would it work to reduce the coolant flow instead of the air flow through the radiators? Maybe a controlable variable volume valve would work. Ah, the fun continues.
Good luck, Sam 4106


Title: Re: Electric Fan or hydraulic motor
Post by: prevost82 on August 27, 2007, 06:09:27 PM
I would put a Horten air hub on it. You maybe fine on the flat but what about a hot day (95+) running up a 6 to 7% grade for 12 to 16 miles. You may need all the cooling you've got. Adding hydraulics just adds to the complexity to your cooling system.
Ron


Title: Re: Electric Fan or hydraulic motor
Post by: NewbeeMC9 on August 27, 2007, 06:44:20 PM
http://www.hi-lo.com/pages/products12-99.html (http://www.hi-lo.com/pages/products12-99.html)  they claim to have these up to 125 hp

or here,  some body here could tell you what hp,  i guess 20 or 30

http://www.speedselector.com/fixer.htm (http://www.speedselector.com/fixer.htm)

I'm sure hydraulic's would be cool.  

However, i vote for changing pulley size as simplist, easiest, cheapest, and most reliable.  maybe not bigggest savings but the savings/effort ratio would be up there.

DIYW

let us know what you come up with.


Title: Re: Electric Fan or hydraulic motor
Post by: Busted Knuckle on August 27, 2007, 06:50:24 PM
I'd have to agree with the Horten (or other brands) air or electric clutch set up! The Horten should be the easiest as they are common on big trucks already and should be easy to get one for your application at either a truck dealer or truck parts supply house! This way you can have it set to come on by thermostat or a manual over ride switch! JMHO FWIW!  ;D  BK  ;D


Title: Re: Electric Fan or hydraulic motor
Post by: TomC on August 27, 2007, 09:48:49 PM
Brian- I have an 8 blade 30" aluminum fan with a 3" pitch that runs all the time.  On cool days, the temp stays right at 175 degrees.  Then climbing it will get to 185.  Above that I kick on the misters.  But the fan is running all the time.  It is better to have the engine at a constant temp than to have it climb up and down sometimes close to 20 degrees with the themostatically operated shutters.  If your engine is not getting up to at least 175 degrees with a 180 thermostat, then a replacement is needed.  I would suggest you run the bus as is for a few more thousand miles to get the rhythm of the bus.  No need to worry about this to much now!  Good Luck, TomC


Title: Re: Electric Fan or hydraulic motor
Post by: Brian Diehl on August 28, 2007, 07:02:41 AM
Thanks everyone for all the ideas and feedback.  I have replaced the thermostat.  What I've learned so far is if I keep the front heater core valve open the engine never comes up fully to temperature.  If I shut the heatercore valve off it will come up to temp fairly quickly.  I have not yet experimented with how much I can open the heatercore valve and still keep it up to temperature.

I think for now I'll simply experiment with restricting the amount of air moved by the blowers.  Then, as was suggested, put a bunch of miles on to make sure I know how it handles high temperatures and long grades.  After I'm comfortable with how it responds then I'll look at a clutch based system or better yet a variable speed system.  *Ideally* I'd be able to have a two speed system.  Slow for when I just need air flowing through the CAC and high for when I'm climbing that long grade!