A Cars forum. AutoBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AutoBanter forum » Auto makers » BMW
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

A funny thing happened on the way thru an oil change



 
 
Thread Tools Display Modes
  #21  
Old July 7th 05, 09:09 PM
Huw
external usenet poster
 
Posts: n/a
Default


"Dave Plowman (News)" > wrote in message
...
> In article >,
> Malt_Hound > wrote:
>> Which brings me to another thought... why do we need fans that run
>> directly off the engine, increasing and decreasing with engine speed,
>> when in all reality, the biggest need for additional air flow thru the
>> radiator will be at the lowest engine speed, and the least need for the
>> fan will be at higher rpm when we are making good speed?

>
>> Seems like an intelligently controlled electric fan would be a better
>> design, no?

>
> Or a progressively driven mechanical one which idles when not needed...
>


The latest hi-tech zenith of efficiency is the Viscotronic fan. This has an
engine management controlled variable speed viscous fan. It is an amazing
piece of kit. I happen to have a bit of experience with an application where
a diagnostic laptop can be linked to the vehicle and the speed of the fan
can be infinitely varied within reason by means of mouse on slider. It so
happens that I have two near identical vehicles except that one has a simple
viscous coupled fan and the other having the latest viscotronic unit and the
reduction of noise from the latter is very noticeable. With the same fan
blades it is probable that this equates to a significant gaining of
horsepower or reduction in fuel consumption.

Huw


Ads
  #22  
Old July 7th 05, 09:13 PM
Huw
external usenet poster
 
Posts: n/a
Default


"Ross Garrett" > wrote in message
...
>
> "Jan Kalin" > wrote in message
> ...
>> In article >, Ross Garrett wrote:
>>>
>>>"Malt_Hound" > wrote in message
...
>>>
>>>> Which brings me to another thought... why do we need fans that run
>>>> directly off the engine, increasing and decreasing with engine speed,
>>>> when
>>>> in all reality, the biggest need for additional air flow thru the
>>>> radiator
>>>> will be at the lowest engine speed, and the least need for the fan will
>>>> be
>>>> at higher rpm when we are making good speed?
>>>>
>>>> Seems like an intelligently controlled electric fan would be a better
>>>> design, no?
>>>
>>>I am pretty certain the new era of BMW's have electric radiator fans. I
>>>thought I read somewhere that is one of the means they used to lower
>>>engine
>>>loading to increase power yet maintain fuel efficiency (apparently better
>>>battery capabilities mean less load without the fan belt, but also no
>>>increased load for the alternator). The fan and fan speed are driven by
>>>signals from the engine controller. I also think they might have electric
>>>water pumps for the same reason.
>>>
>>>And I know both my E39's had at least some semblance of an electric fan
>>>because it would run long after the engine shut down on hot days when the
>>>AC
>>>had been used.

>>
>> That's the auxillary electrical fan for cooling AC condenser. The main
>> fan
>> is mechanical with a viscous clutch. Check out
>> http://www.realoem.com/bmw/partgrp.d...44&hg=11&fg=35
>> for the main fan (located between the radiator and engine) and
>> http://www.realoem.com/bmw/partgrp.d...44&hg=64&fg=55
>> for the AC fan (located in front of the radiator).

>
> Thanks. I was wrong on the new cars' water pump too. The site clearly
> shows the water pump and alternator run from the same belt.
>


Diesel versions have an extra electric water pump which continues to pump
coolant around the turbocharger bearing and cylinder head area after
shut-down.

Huw


  #23  
Old July 7th 05, 09:56 PM
Jeff Strickland
external usenet poster
 
Posts: n/a
Default


"Dave Plowman (News)" > wrote in message
...
> In article >,
> Malt_Hound > wrote:
> > Yeah, but my SAABs with 4 cylinder transverse engines all had electric
> > fans, and they were pretty darn reliable.

>
> With a transverse engine and a front mounted rad it would be difficult to
> have an engine driven fan...


It would be difficult to have an engine driven fan that was between the
engine and the radiator. If one didn't care where the fan was relative to
where the radiator was, then it would be a relatively simple matter to have
an engine driven fan. It wouldn't be a very useful fan though.


  #24  
Old July 7th 05, 10:07 PM
Dave Plowman (News)
external usenet poster
 
Posts: n/a
Default

In article >,
Jeff Strickland > wrote:
> > With a transverse engine and a front mounted rad it would be difficult
> > to have an engine driven fan...


> It would be difficult to have an engine driven fan that was between the
> engine and the radiator.


Not so - the original Mini did just this. With a side mounted rad...

> If one didn't care where the fan was relative
> to where the radiator was, then it would be a relatively simple matter
> to have an engine driven fan. It wouldn't be a very useful fan though.


--
*A bartender is just a pharmacist with a limited inventory *

Dave Plowman London SW
To e-mail, change noise into sound.
  #25  
Old July 8th 05, 05:26 AM
news
external usenet poster
 
Posts: n/a
Default

great, another thing that can go wrong and cause overheating -
an electric water pump.
is it so much better than the aluminum one in the newer E36 ?


>>and BMW is using an electric water pump (engine cooling,

not just heater core flow) in the E90...


  #26  
Old July 11th 05, 04:41 PM
spare-me-spam
external usenet poster
 
Posts: n/a
Default

Dave Plowman (News) wrote:
>> In article >,
>> Malt_Hound > wrote:
>>> Which brings me to another thought... why do we need fans that run
>>> directly off the engine, increasing and decreasing with engine
>>> speed, when in all reality, the biggest need for additional air
>>> flow thru the radiator will be at the lowest engine speed, and the
>>> least need for the fan will be at higher rpm when we are making
>>> good speed?

>>
>>> Seems like an intelligently controlled electric fan would be a
>>> better design, no?

>>
>> Or a progressively driven mechanical one which idles when not
>> needed...


err, but it DOES do just that.....


  #27  
Old July 11th 05, 05:51 PM
Dave Plowman (News)
external usenet poster
 
Posts: n/a
Default

In article >,
spare-me-spam > wrote:
> >>> Seems like an intelligently controlled electric fan would be a
> >>> better design, no?
> >>
> >> Or a progressively driven mechanical one which idles when not
> >> needed...


> err, but it DOES do just that.....


;-)

--
*Those who live by the sword get shot by those who don't.

Dave Plowman London SW
To e-mail, change noise into sound.
  #28  
Old July 24th 05, 01:31 PM
Malt_Hound
external usenet poster
 
Posts: n/a
Default

Huw wrote:

> The latest hi-tech zenith of efficiency is the Viscotronic fan. This has an
> engine management controlled variable speed viscous fan. It is an amazing
> piece of kit. I happen to have a bit of experience with an application where
> a diagnostic laptop can be linked to the vehicle and the speed of the fan
> can be infinitely varied within reason by means of mouse on slider. It so
> happens that I have two near identical vehicles except that one has a simple
> viscous coupled fan and the other having the latest viscotronic unit and the
> reduction of noise from the latter is very noticeable. With the same fan
> blades it is probable that this equates to a significant gaining of
> horsepower or reduction in fuel consumption.


Cool beans...

That is the exact bit of trivial detail that had me asking the question
in the first place. On my Z3, once the engine reaches full temperature,
the fan noise at normal engine rpm (above 3000 rpm) is annoying, even
though I'm tooling along at a high enough rate of speed so that the need
for the fan is negligible.

-Fred W

PS - I'm just back from 2 weeks R&R in northern Maine, in case anyone
missed me (or hoped I had dropped off the planet...)
  #29  
Old July 24th 05, 02:28 PM
Malt_Hound
external usenet poster
 
Posts: n/a
Default

spare-me-spam wrote:
> Dave Plowman (News) wrote:
>
>>>In article >,
>>> Malt_Hound > wrote:
>>>
>>>>Which brings me to another thought... why do we need fans that run
>>>>directly off the engine, increasing and decreasing with engine
>>>>speed, when in all reality, the biggest need for additional air
>>>>flow thru the radiator will be at the lowest engine speed, and the
>>>>least need for the fan will be at higher rpm when we are making
>>>>good speed?
>>>
>>>>Seems like an intelligently controlled electric fan would be a
>>>>better design, no?
>>>
>>>Or a progressively driven mechanical one which idles when not
>>>needed...

>
>
> err, but it DOES do just that.....
>
>


No, it doesn't. The fan runs even when the car is moving forward at a
high speed forcing more air through the radiator than the fan ever could.

-Fred W
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Big Bertha Thing blogs Tony Lance Chrysler 8 January 15th 05 03:05 PM
eScrew [email protected] Driving 0 December 20th 04 11:52 AM
es [email protected] Chrysler 0 December 20th 04 11:16 AM


All times are GMT +1. The time now is 01:50 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AutoBanter.
The comments are property of their posters.