X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 30 [X] Return-Path: Sender: To: lml Date: Thu, 07 Dec 2006 13:10:30 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m21.mx.aol.com ([64.12.137.2] verified) by logan.com (CommuniGate Pro SMTP 5.1.3) with ESMTP id 1650412 for lml@lancaironline.net; Thu, 07 Dec 2006 09:49:08 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.2; envelope-from=REHBINC@aol.com Received: from REHBINC@aol.com by imo-m21.mx.aol.com (mail_out_v38_r7.6.) id q.c05.b72bbfa (48336) for ; Thu, 7 Dec 2006 09:47:55 -0500 (EST) Received: from mblk-r15 (mblk-r15.mblk.aol.com [152.163.211.206]) by ciaaol-d01.mail.aol.com (v114.2) with ESMTP id MAILCIAAOLD016-bcd04578299b3e7; Thu, 07 Dec 2006 09:47:55 -0500 References: X-Original-To: lml@lancaironline.net Subject: Re: [LML] Friction loss X-Original-Date: Thu, 07 Dec 2006 09:47:55 -0500 In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: rehbinc@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8C8E825D06B918A_778_4CE2_mblk-r15.sysops.aol.com" X-Mailer: AOL Email 22250 Received: from 81.3.89.82 by mblk-r15.sysops.aol.com (152.163.211.206) with HTTP (WebMailUI); Thu, 07 Dec 2006 09:47:55 -0500 X-Original-Message-Id: <8C8E825D06DF3DE-778-27E7@mblk-r15.sysops.aol.com> X-AOL-IP: 152.163.211.206 X-Spam-Flag: NO ----------MB_8C8E825D06B918A_778_4CE2_mblk-r15.sysops.aol.com Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii" Dry sliding friction force is independent of sliding rate, at least in theory. However, hydrodynamic friction force generelly varies with the square of the change in rate. The journal bearings in the engine are purely hydrodynamic as are the pistons. Increases in cylinder pressure don't have much effect on ring coefficient of friction, but they have a direct effect on the contact force and hence the frictional force. -----Original Message----- From: elippse@sbcglobal.net To: lml Sent: Tue, 5 Dec 2006 6.37PM Subject: [LML] Friction loss Friction or Coulomb* loss is independent of sliding rate. However, the friction loss in pounds, when multiplied by rate, yields hp. As rpm goes up, so does the friction hp. Also, as rpm goes up, engine power, at a given MEP, also goes up proportionatly. It would seem that the friction hp would maintain a certain percentage of the overall power input, and I'm not sure how this would cause a change in SFC. Also, I'm not sure of the effect of increased MEP on the coefficient of friction. Does it go up with the increased pressure of the rings against the cylinder walls at higher MEP? Keeping MEP max certainly cuts down on pumping loss! I seek enlightenment! *Charles Augustin de Coulomb ----------MB_8C8E825D06B918A_778_4CE2_mblk-r15.sysops.aol.com Content-Transfer-Encoding: 7bit Content-Type: text/html; charset="us-ascii"
Dry sliding friction force is independent of sliding rate, at least in theory. However, hydrodynamic friction force generelly varies with the square of the change in rate. The journal bearings in the engine are purely hydrodynamic as are the pistons.
 
Increases in cylinder pressure don't have much effect on ring coefficient of friction, but they have a direct effect on the contact force and hence the frictional force. 
 
 
-----Original Message-----
From: elippse@sbcglobal.net
To: lml
Sent: Tue, 5 Dec 2006 6.37PM
Subject: [LML] Friction loss

Friction or Coulomb* loss is independent of sliding rate. However, the friction loss in pounds, when multiplied by rate, yields hp. As rpm goes up, so does the friction hp. Also, as rpm goes up, engine power, at a given MEP, also goes up proportionatly. It would seem that the friction hp would maintain a certain percentage of the overall power input, and I'm not sure how this would cause a change in SFC. Also, I'm not sure of the effect of increased MEP on the coefficient of friction. Does it go up with the increased pressure of the rings against the cylinder walls at higher MEP? Keeping MEP max certainly cuts down on pumping loss! I seek enlightenment!
 
*Charles Augustin de Coulomb
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