Date: Mon, 2 Jun 2003 23:13:17 -0400
Reply-To: Dennis Haynes <dhaynes@OPTONLINE.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <dhaynes@OPTONLINE.NET>
Subject: Re: 1982 EGR valve Redux, now flaming cylinder heads
In-Reply-To: <003201c32979$e798d380$7f2bf9d0@david1>
Content-type: text/plain; charset=US-ASCII
The primary purpose of the EGR valve is to reduce NOx emissions. I guess
the 3-way Cat with the O2 sensor combined with retarded timing settings
was not sufficient in the air cooled engines so the EGR remained. The
method of operation is that during part throttle operation, some exhaust
gas is re-circulated back into the cylinders. As the exhaust should be
devoid of fuel and oxygen, it is basically inert, (in theory). As such,
it takes up room in the cylinder, reducing the space for the air fuel
mixture, reducing the combustion effective compression ratio. This
lowers the "peak" flame temperature which reduces the production of NOx.
A side benefit is lower head and piston temperatures and reduced
tendency for pre-ignition. This allows the ignition timing to be more
advanced providing some performance and fuel economy advantages. At idle
and full throttle the valve should be closed. The fuel mixture is
richened at full throttle to keep things from burning up and to provide
more power.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf
Of David and Shirin
Sent: Monday, June 02, 2003 10:43 PM
To: vanagon@GERRY.VANAGON.COM
Subject: 1982 EGR valve Redux, now flaming cylinder heads
I was looking for more of a technical answer Bill, but the flames were
noted, and certainly do warm the heart.
I wonder if the EGR valve is also responsible for keeping combustion
temps down as this is one way of reducing NOX emissions. Maybe that's
contributing to the higher than normal oil and cylinder head temps.
Anyone have any data on this?
Date: Mon, 2 Jun 2003 13:48:05 -0700
From: Bill N <freeholder@STARBAND.NET>
Subject: Re: 1982 EGR valve
What "good" it does is exactly what you stated in your post. It helps
keep emissions in check.
Running without it is illegal in most states in the USA. It is
certainly immoral everywhere.
In your spare time do you pour chemicals into waterways? Hunt
endangered species? Just how
far does your lack of concern for the environment extend?
Bill in the Southwest
----- Original Message -----
From: "David and Shirin" <daveshirin@ENERGYUNITED.NET>
Is it really necessary to have the EGR valve working on a 1982 aircooled
vanagon? Other than
keeping emissions in check what good does it do? I have been running
with mine unhooked for a
while now and have noticed no difference.
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