air filter

[Guest]

Hi Guys
Ok just to ask a few silly questions.
The air filter is the only way for abrasive dirt to enter the engine is it
not.
Is it not this dirt that is responsible for damage and premature ware within
the engine so it does make sense to exclude as much as possible.
But and here are the questions how do you know how much air the engine needs
at any given time.
If it gets too little will it start to complain.
Is the speed and volume of the air entering the engine determined by the
road speed and the pulling power of the pistons or just the pulling power of
the pistons.
Just thinking, at a stand still with the engine running even at high revs it
still gets enough air to work properly.
As for the ram air effect with a snorkel would it not keep out more dirt if
it was turned backwards in bad conditions.
If you look at all the big trucks they all have their filter snorkels to
the side of the cab.
So this must be to protect those expensive engines is it not.
Can you install a pre filter filter on the cruiser in the inlet pipe to the
rear of the head light or would this constrict flow.
cheers
john 92HDJ 80 1HDT

 

[Guest]

The RAM air effect, as used on motorcycles such as the Kawasaki ZZR, Honda
Hayabusa etc, is only effective at speeds over 200 km/h.
Never seen a cruiser cruising at this speed - and wouldn't want to be in
one.
So the air an engine needs at any given moment is determined by :
* The engine size (obviously a 4.2 l engine needs 4.2 l of air, whereas a
1.3 engine only needs 1.3 l of air)
* The rotations per minute
So a 4.2 l rotating at 1.800 rotations per minute needs 4.2 l x 1.800 = 7560
l of air per minute, at standstill or driving doesn't make a difference.
Or is my thinking wrong ?
Cedric
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]] On
Behalf Of john byrne
Sent: mardi 16 octobre 2007 12:34
To: [Email address removed]
Subject: Re: [ELCO] air filter
Hi Guys
Ok just to ask a few silly questions.
The air filter is the only way for abrasive dirt to enter the engine is it
not.
Is it not this dirt that is responsible for damage and premature ware within
the engine so it does make sense to exclude as much as possible.
But and here are the questions how do you know how much air the engine needs
at any given time.
If it gets too little will it start to complain.
Is the speed and volume of the air entering the engine determined by the
road speed and the pulling power of the pistons or just the pulling power of
the pistons.
Just thinking, at a stand still with the engine running even at high revs it
still gets enough air to work properly.
As for the ram air effect with a snorkel would it not keep out more dirt if
it was turned backwards in bad conditions.
If you look at all the big trucks they all have their filter snorkels to
the side of the cab.
So this must be to protect those expensive engines is it not.
Can you install a pre filter filter on the cruiser in the inlet pipe to the
rear of the head light or would this constrict flow.
cheers
john 92HDJ 80 1HDT

 

[Guest]

as i said roman, i've spent all my time south of the sahara so the situation
will be different. us folk all have different experiences and that's what
makes any forum a great place to learn.
jeremy "--" --
self-drive safaris in east and southern africa
www.--
uk mobile: +44 (0)
uk landline: +44 (0)
skype: Fred
-----original message-----
from: [email address removed] [mailto:[email address removed]] on
behalf of roman
sent: 16 october 2007 13:12
to: [email address removed]
subject: re: [elco] air filter
jeremy,
plenty of them in libya, algeria, mauritania, mali .... all those
areas where dust is a problem. when you pour out a handful of fine
dust from the bowl at the end of the day you know they do work.
--
rgds,
roman (london, uk)
'92 hdj80 (auto)

no virus found in this incoming message.
checked by avg free edition.
version: 7.5.488 / virus database: 269.14.10/1070 - release date: 14/10/2007
09:22
no virus found in this outgoing message.
checked by avg free edition.
version: 7.5.488 / virus database: 269.14.10/1070 - release date: 14/10/2007
09:22

 

[Guest]

Cedric
| So a 4.2 l rotating at 1.800 rotations per minute needs 4.2 l x 1.800
=3D 7560
| l of air per minute, at standstill or driving doesn't make a
difference.
|
| Or is my thinking wrong ?
Nearly right!
A 4 stroke cylinder only sucks in air every other revolution, so actual
volume for each revolution is 2.1 litres. So at 1800 rpm that's 3780
litres, or about 4kg or air a minute at atmospheric pressure (ordinary
dryish air at 20 deg C is around 1.2kg/1000 litres).
To complicate matters on a turbo-charged engine at tickover the pressure
at the inlet manifold will be a bit below atmospheric, but as the turbo
cuts in so the pressure will rise and it will ram in more air.
So at full boost, around 9 psi as I recall on our machines, the inlet
air pressure will be a bit more than 1.5 atmospheres. To make the maths
easy let's say this happens at 3600 rpm, so the volume of air swallowed
will be twice that at 1800 rpm, ie 7560 litres/minute; but the mass will
be around 10kg/minute.
We've ignored heating: pressurising the air with the turbo heats it up
and makes it expand, making it harder to get so much of it into the
cylinders, so perhaps it's more like 9 kg/minute. This is why
inter-coolers are good: they cool the air down, making it denser, so you
get more mass (ie more oxygen molecules) into the cylinders and can burn
more fuel.
Bottom line though: any air filtering system you fit needs to handle at
least 10kg of air/minute.
Christopher Bell
____________________________________________________________
Electronic mail messages entering and leaving Arup business
systems are scanned for acceptability of content and viruses

 

[Guest]

Aha, yes indeed, I am not used to drive these turbo wonders, but forgot all
about it. And school is almost 20 years ago. Interesting reading - thanks,
Cedric
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]] On
Behalf Of Christopher Bell
Sent: mardi 16 octobre 2007 13:29
To: [Email address removed]
Subject: RE: [ELCO] air filter
Cedric
| So a 4.2 l rotating at 1.800 rotations per minute needs 4.2 l x 1.800
= 7560
| l of air per minute, at standstill or driving doesn't make a
difference.
|
| Or is my thinking wrong ?
Nearly right!
A 4 stroke cylinder only sucks in air every other revolution, so actual
volume for each revolution is 2.1 litres. So at 1800 rpm that's 3780
litres, or about 4kg or air a minute at atmospheric pressure (ordinary
dryish air at 20 deg C is around 1.2kg/1000 litres).
To complicate matters on a turbo-charged engine at tickover the pressure
at the inlet manifold will be a bit below atmospheric, but as the turbo
cuts in so the pressure will rise and it will ram in more air.
So at full boost, around 9 psi as I recall on our machines, the inlet
air pressure will be a bit more than 1.5 atmospheres. To make the maths
easy let's say this happens at 3600 rpm, so the volume of air swallowed
will be twice that at 1800 rpm, ie 7560 litres/minute; but the mass will
be around 10kg/minute.
We've ignored heating: pressurising the air with the turbo heats it up
and makes it expand, making it harder to get so much of it into the
cylinders, so perhaps it's more like 9 kg/minute. This is why
inter-coolers are good: they cool the air down, making it denser, so you
get more mass (ie more oxygen molecules) into the cylinders and can burn
more fuel.
Bottom line though: any air filtering system you fit needs to handle at
least 10kg of air/minute.
Christopher Bell
____________________________________________________________
Electronic mail messages entering and leaving Arup business
systems are scanned for acceptability of content and viruses

 

[Guest]

Oh look out the guys gmail is making funny. I got Cedric reply to
Christophe Bell but never got the email of Christophe!
Now so that Christophe has painted the terms very clear with math and
physics, we do know how much air we do need. We are edified guys.
But Christophe, what if we have Maartens 11 psi turbo put in and his
kit intercooler too? So how much litres of air do I need now? I do not
know how to weigh kilograms of air, I am sorry.

 

[Guest]

To be a little more precise on the air required by the engine without a
turbo - the proportion of the theoretical airflow that actually goes into
the engine is the volumetric efficiency of the engine, normally at about say
85% so at 1800, it's 3780 * 0.85 = approx 3200 litres. Volumetric
efficiency normally reduces past the "red line" hence the reason power
output doesn't keep increasing. Now you see why the turbo is so useful.
On the cyclone per filters - we sometime use them on generators - surprising
what they catch even on a static genset in the UK in a mildly dusty building
site for instance.
Malcolm Bagley
Stafford UK
FJ45 '75 & FJ45 '76
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.488 / Virus Database: 269.14.11/1071 - Release Date: 15/10/2007
06:48

 

[Guest]

On 10/16/07, Benoit Bernard <[Email address removed]> wrote:
Benoit,
That's quite straightforward using ordinary bathroom scales. Take a
deep breath. Step on the scales and record your weight. Next, release
butt cheeks and compare the results. Finally, multiply the volumetric
mass so obtained by 0.59495548961424332344213649851632 (methane to air
atomic weight ratio).
Sorry, couldn't resist
--
Rgds,
Roman (London, UK)
'92 HDJ80 (auto)

 

[Guest]

Roman / Benoit
That's one of Einstein's lesser known formulas.
Sometimes referred to as: Butt Cheeks =3D MC Squared
Cheers Niall
Snip
That's quite straightforward using ordinary bathroom scales. Take a deep
breath. Step on the scales and record your weight. Next, release butt
cheeks and compare the results. Finally, multiply the volumetric mass so
obtained by 0.59495548961424332344213649851632 (methane to air atomic
weight ratio).

 

[Guest]

Oh I get it guy's it means 6.03 x 10 23rd - smile face!