Vanagon EuroVan
Previous messageNext messagePrevious in topicNext in topicPrevious by same authorNext by same authorPrevious page (September 2000, week 1)Back to main VANAGON pageJoin or leave VANAGON (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:   Thu, 7 Sep 2000 16:10:53 EDT
Reply-To:   FrankGRUN@AOL.COM
Sender:   Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:   Frank Grunthaner <FrankGRUN@AOL.COM>
Subject:   Re: Thinking swap? Engine options are only half the story...What about the t...
Comments:   To: thewestyman@mindspring.com
Content-Type:   text/plain; charset="US-ASCII"

True. The other point to be made here is that there is no localization of the pressure pulse along the vector of the arc formed by the spark discharge. The fuel ignition is a free radical triggered reaction and diffusion limited. The flame front moves at supersonic (averaged) velocities traversing the chamber in a few hundred nanoseconds to microseconds depending on chamber geometry. The heat released by combustion then heats the surrounding gas by conduction (process too fast for convective effects) and the details of the pressure rise now depend on internal chamber mixing. This includes swirl, squish and valve overlap as well as the detailed shape of the piston surface and the stroke (piston dwell time).

The primary impact of a centrally located plug is the need to diffusively trigger the reaction as opposed to radiatively preheating areas of the chamber to trigger a metastable mixture.

Even surface gap-plugs are not capable of a centro-symmetric arc.

frank Grunthaner


Back to: Top of message | Previous page | Main VANAGON page

Please note - During the past 17 years of operation, several gigabytes of Vanagon mail messages have been archived. Searching the entire collection will take up to five minutes to complete. Please be patient!


Return to the archives @ gerry.vanagon.com


The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.

Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.