Date:         Fri, 10 Sep 1999 16:54:45 +0200
Reply-To:     Per Lindgren <lindgre@ONLINE.NO>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Per Lindgren <lindgre@ONLINE.NO>
Subject:      Re: New 1,9 TDI from VW
Comments: To: Michael Townsend <townsend@rtp.ericsson.se>
Content-Type: text/plain; charset=us-ascii

Michael Townsend wrote:

> Hi,
>
> Does "unit injection" mean common rail injection?

No, it doesn't. While the common rail makes use of a rail to distribute the
fuel, the VW system has a quite different approach. The injection pumps are
mounted directly in the cyl. head, one for each cylinder. These injectors
are activated over rockers from the camshaft, and can manage pressures of up
to 2000 bars. Take a look at
http://www.volkswagen.de/technik/4_pumped/oben_.htm for info, but the text
is in German only, so use the altavista translation service to get the
general idea, http://babelfish.altavista.digital.com VW has much info about
the engine on their website.

The common rail system consist of pressurized fuel lines (1300 BAR) and
injectors that open a given amount at a given time. All controlled by the
ECU.

What is common with all new types of diesel engines are the direct
injection, turbocharger and intercooler. Many are also multivalve engines.

PerL
87 Syncro 112i