is there any electric fans that will produce the same or better cooling ?
Electric Fans are not really an effective method of cooling a diesel in a bus.
There have been a few that tried that only to find monumental engineering
problems or the need to find enough electric power to operate the motors
which wouldn't be cost or efficiency effective.
A Hydraulic or Belt driven fan is the current working technology. Low maintenance and effective.
Others may also have comments on this.
Hi mccarlk,
I don't think electric propeller fans can come close to the cfm's that the belt driven squirrl cage types can put out.
That don't mean it can't be done but, the dementions of the two MCI rads are not that wide to fit a large diameter fan.
Even two stacked top/bottom, will be a small set up. A better idea would be a 24v squirrl blower from the A/C system.
Good Luck
Nick-
I have saw the 24v blower motor used on a MCI 5 and it did not work the guy went back with belt.Mark Renner is about the only person that has been able to make a electric fan work but he owns a Eagle and did a lot of enginering on his to make it work
It takes a certain volume of air to cool the radiator.
It takes HP to move air.
If you change nothing else, it will take the same HP to move sufficient air to to cool the engine. The air & fan do not know or care if the energy is from a belt, electric motor, or hyd motor.
Now, if you were to improve the fan's efficiency . . . .
However, most find it difficult to get sufficient air flow with electric motors driving the fans . . . as it is difficult to get around the required large amp draw. :(
WHY? If a belt breaks, you replace the belt and you are on your way. If an electic fan fails, you are stuck until you get a new one. As well as all the aforementioned reasons. Jack
Quote from: kyle4501 on August 15, 2008, 08:14:49 PM
It takes a certain volume of air to cool the radiator.
It takes HP to move air.
If you change nothing else, it will take the same HP to move sufficient air to to cool the engine. The air & fan do not know or care if the energy is from a belt, electric motor, or hyd motor.
Seems like it would take even more power due to the inherent losses in the conversion of energy. First, motion is converted to electricity by the alternator. Some loss takes place. Then it is converted back to motion in the fan motor. Some more loss takes place.
I am glad my RTS fan belt is a very short little 12 rib belt (about 12.5" diameter). It's very durable and doesn't give me the heebie jeebies being around the open engine hatch Like an MCI's belts do. If I had huge long belts winding all over between me and the engine, I might be thinking about electric as well though.
im even considering the hydraulic ones, and a side mount rad
Ken, look on BNO Mark Renner has photos of his electric fan setup with a side mount radiator he used 12v fans so your 24 v system will draw less amp than his it is a clean setup that works
http://www.busnut.com/bbs/messages/233/20829.html
I really like what Mark has done, if I had done all that, I wouldn't have documented as well as he has. ;D
(But . . . I have lots of questions concerning the "hidden details".)
So, read & UNDERSTAND what he has done. :o
4 strokes require less cooling than 2 strokes. (While it did work for ~1000 miles on the 6V92, there isn't enough details to satisfy all my concerns. Like what was the waterflow?, what rate was the engine temp changing?, What HP was the engine making?, etc. )
Also note that he put considerable effort into the install, just look at the fan shrouds. 8)
I tried (and failed) at putting in an electric fan. Spent more on that project than an in-frame would have cost (no labor included of course).
I had to build my own motor controller for the 15HP motor, and while I did do that succesfully - the performance was a bit less than what I'd hoped. I also had to go from a 200Amp 24v alternator to a 300Amp. If anything broke down on the road - I would have been waiting there for about a week for replacement parts to come since it was all custom (at the same cost as installation $$$$$$).
I went back to the hydraulic fan that came with the bus - but changed the speed control valve to be a bit more "intelligent". Much cheaper, way more reliable, loads easier to find parts for at 6AM on a saturday...
Mc,
Don't go there. I have heard this topic discussed more than a few times over the years. There are soooooo many things you can do and spend even more money and be assured that they will "bare" fruit.
I am drawn to projects that people say "can't be done". Lots of satisfaction in completing one. This isn't it though from all I can tell.
HTH,
John
Tim - thanks for the HONEST come back - If you can't do it, no one can - FWIW
Electric fan technology has improved over the past 5 years construction equipment manufactures like John Deere, Cat,Volvo and etc. are using them more everyday have a great day
Quote from: makemineatwostroke on August 20, 2008, 04:38:19 AM
Electric fan technology has improved over the past 5 years construction equipment manufactures like John Deere, Cat,Volvo and etc. are using them more everyday have a great day
The trick to that is the construction equipment has a higher capacity cooling system
than what you would find in a Bus. The theory is that construction equipment is
designed mostly for static operation where the fans work the best.
OTR and other stuff that has positive air flow is slightly different.
I had the thoughts in my head, But couldn,t get my fingers to cooperate
I don't want to hijack this thread but I was wondering about reconfiguring the radiators on my MC7 if I turbo the stock engine.
If I remove the fan access door completely I have a radiator (single) built to fit the entire space, it looks like I would have almost twice the cooking area. I would remove the stock fans & rads and cool with 4 electric fans with the appropriate shrouds. access through the old side radiator inlet air ducts, which would be covered by a solid door to force the air down over the engine like the original design.
Just thinking out loud here......
TOM
Quote from: oldmansax on August 20, 2008, 05:23:40 AM
If I remove the fan access door completely I have a radiator (single) built to fit the entire space, it looks like I would have almost twice the cooking area. I would remove the stock fans & rads and cool with 4 electric fans with the appropriate shrouds. access through the old side radiator inlet air ducts, which would be covered by a solid door to force the air down over the engine like the original design.
TOM
Tom,
Would the fans be fighting a negative pressure that forms behind the bus when driving? Jack
After reading many posts relating to electric fans and understanding the air flow requirements, I'm under the opinion that using the stock radiators or even extra row radiators will not work with a simple electric fan system. However I beleive that a simple electric fan system will work if one were to reconfigure the radiator cooling system and replace the original radiators with radiator(s) with more square inches of air entry and possibly less rows. With the larger surface area, multiple simple electric fans could then be used. This is what I believe Tom is suggesting. No matter how its done, total heat rejection of the cooling system still needs to be the same or better. Simply put, thick small surface area radiator and a high velocity fan as in the original system or a reconfigured thinner large surface area radiator with multiple simple lower velocity electric fans. Of course this would require to some a pretty extensive cooling compartment rework. Just my two cents - Kenny
Building pressure doesn't take much HP. Moving large volumes of air does. :(
(That's why shutters are used.)
Even with thinner radiators, you have to have air flow to get cooling.
If you took it to the extreme, a large enough radiator wouldn't need a fan as the natural convection would be enough.
However, the more radiator surface area you have, the more space you loose for other things . . .
That is the primary reason for the existing cooling system. That & the cost involved . . .
Jack,
I thought about the negative pressure aspect but I don't know how much negative pressure there is ..... perhaps you or someone else more knowledgeable can enlighten me!
I also thought of a second configuration with the same large rad & fans but leave the existing rad air intakes on the sides open; fans would draw air from the sides just as stock & blow it through large single radiator exiting the back behind bus. The problem with that (I think) is no cooling air would go down into the engine compartment. If I leave the existing holes in the bulkhead between the fan compartment & the engine compartment open, I will be drawing hot air from the engine into the cooling air for the rad.
Another idea would be to use the first configuration I described and mount an airfoil on the roof to direct air down the back of the bus ... like the kind they used to put on station wagons to keep the back glass clean except bigger.
What do you think?
TOM
The negative pressure is strictly a guess on my part. I was just thinking of all the dirt that gets sucked onto the back of the bus and how much gets on our toad. Maybe someone can enlighten us on just what all that air we are pushing through does when it gets to the back of the bus. Anyone got a wind tunnel big enough for a bus? LOL Jack
Quote from: JackConrad on August 21, 2008, 06:25:43 AM
The negative pressure is strictly a guess on my part. I was just thinking of all the dirt that gets sucked onto the back of the bus and how much gets on our toad. Maybe someone can enlighten us on just what all that air we are pushing through does when it gets to the back of the bus. Anyone got a wind tunnel big enough for a bus? LOL Jack
It free to anyone. Just go to a parking lot that has an open view to an expressway on a very light or just after heavy rain. You will see how water spray flowed in suction areas as well along sides. Watch how the water is just dropping to payment from behind traveling at the same speed. In other words, allot of suction.
Water manometer will give the comparing results. You have to put about 10 or more pick-up points with rotary valve.
FWIW
Sojourn for Christ, Jerry