Bus Conversions dot Com Bulletin Board
October 24, 2014, 04:31:14 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: If you had an Online Subscription: By clicking on any ad, a hotlink takes you directly to the advertiserís website.
   Home   Help Forum Rules Search Calendar Login Register BCM Home Page Contact BCM  
Pages: [1] 2  All   Go Down
  Print  
Author Topic: Electric Fan or hydraulic motor  (Read 3366 times)
Brian Diehl
Hero Member
*****
Offline Offline

Posts: 984




Ignore
« 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. 
Logged
H3Jim
Hero Member
*****
Offline Offline

Posts: 1398


1995 Prevost H3-41, series 60, B500 Allison




Ignore
« Reply #1 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.
Logged

Jim Stewart
El Cajon, Ca.  (San Diego area)

Travel is more than the seeing of sights, it is a change that goes on, deep  and permanent, in the ideas of living.
kyle4501
Hero Member
*****
Offline Offline

Posts: 3145


PD4501 South Carolina




Ignore
« Reply #2 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  Grin
Logged

I know you believe you understand what you think I said, but I am not sure you realize that what you heard is not what I meant. (R.M. Nixon)
rv_safetyman
Hero Member
*****
Offline Offline

Posts: 2199


Jim Shepherd


WWW

Ignore
« Reply #3 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
Logged

Jim Shepherd
Evergreen, CO
í85 Eagle 10/Series 60/Eaton AutoShift 10 speed transmission
Somewhere between a tin tent and a finished product
Bus Project details: http://beltguy.com/Bus_Project/busproject.htm
Blog:  http://rvsafetyman.blogspot.com/
Brian Diehl
Hero Member
*****
Offline Offline

Posts: 984




Ignore
« Reply #4 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?
Logged
Brian Diehl
Hero Member
*****
Offline Offline

Posts: 984




Ignore
« Reply #5 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  Grin

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?
Logged
DavidInWilmNC
Hero Member
*****
Offline Offline

Posts: 594


1978 MC-8 as I bought it May 2005




Ignore
« Reply #6 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
Logged
kyle4501
Hero Member
*****
Offline Offline

Posts: 3145


PD4501 South Carolina




Ignore
« Reply #7 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.
Logged

I know you believe you understand what you think I said, but I am not sure you realize that what you heard is not what I meant. (R.M. Nixon)
Brian Diehl
Hero Member
*****
Offline Offline

Posts: 984




Ignore
« Reply #8 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?
Logged
tekebird
Hero Member
*****
Offline Offline

Posts: 2263





Ignore
« Reply #9 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?

Logged
Len Silva
Hero Member
*****
Offline Offline

Posts: 4086


Angle Parked in a Parallel Universe


WWW

Ignore
« Reply #10 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
Logged


Hand Made Gifts

Ignorance is only bliss to the ignorant.
Brian Diehl
Hero Member
*****
Offline Offline

Posts: 984




Ignore
« Reply #11 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!  :-)
Logged
kyle4501
Hero Member
*****
Offline Offline

Posts: 3145


PD4501 South Carolina




Ignore
« Reply #12 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.  Grin
Logged

I know you believe you understand what you think I said, but I am not sure you realize that what you heard is not what I meant. (R.M. Nixon)
buswarrior
Hero Member
*****
Offline Offline

Posts: 3571


'75 MC8 8V71 HT740




Ignore
« Reply #13 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
Logged

Frozen North, Greater Toronto Area
Sam 4106
Hero Member
*****
Offline Offline

Posts: 645





Ignore
« Reply #14 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
Logged

1976 MCI-8TA with 8V92 DDEC II and Allison HT740
Pages: [1] 2  All   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines Valid XHTML 1.0! Valid CSS!