Return-Path: <13brv3@bellsouth.net> Received: from imf16aec.mail.bellsouth.net ([205.152.59.64] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 557725 for flyrotary@lancaironline.net; Mon, 06 Dec 2004 12:03:11 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.64; envelope-from=13brv3@bellsouth.net Received: from rd ([65.6.194.9]) by imf16aec.mail.bellsouth.net (InterMail vM.5.01.06.11 201-253-122-130-111-20040605) with ESMTP id <20041206170235.SXLL1980.imf16aec.mail.bellsouth.net@rd> for ; Mon, 6 Dec 2004 12:02:35 -0500 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] ECU oxygen sensor Date: Mon, 6 Dec 2004 11:02:36 -0600 Message-ID: <000001c4dbb5$62967e90$6101a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C4DB83.17FC0E90" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C4DB83.17FC0E90 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I have been looking at various ECUs trying to understand how they work. =20 Fortunately, I was on the phone, and Ed just saved me a lot of typing = :-) One additional note, ECU's can run in open loop, or closed loop modes. Tracy's EC-2 is open loop all the time. Basically, in open loop, you = supply a pre-designated amount of fuel from a look-up table, and you trust that it's what you wanted. When we tune the EC-2, we're making this look-up table. In closed loop mode, you start with the look up table number, = then check the O2 sensor to see how close you came. The ECU can add or = remove fuel as needed to hit a target O2 number. Cars use closed loop whenever they can, or emissions and fuel = efficiency, but they also run in open loop mode under certain conditions. For = example, you're car will run in open loop mode when you first start it, because there's no valid O2 sensor reading until it warms up. Multi-wire heated = O2 sensors have shortened this time considerably over the years. I think = most cars also run in open loop mode during full throttle operation. Rusty =20 ------=_NextPart_000_0001_01C4DB83.17FC0E90 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

I have been looking at various ECUs trying to = understand how=20 they
work. 

Fortunately, I was on the phone, = and Ed just=20 saved me a lot of typing :-)   One additional note, ECU's can = run in=20 open loop, or closed loop modes.  Tracy's EC-2 is open loop all the = time.  Basically, in open loop, you supply a pre-designated = amount of=20 fuel from a look-up table, and you trust that it's what you = wanted.  When=20 we tune the EC-2, we're making this look-up table.  In closed loop = mode,=20 you start with the look up table number, then check the O2 sensor to see = how=20 close you came.  The ECU can add or remove fuel as needed to hit a = target=20 O2 number.

Cars use closed loop whenever they = can, or=20 emissions and fuel efficiency, but they also run in open loop mode under = certain=20 conditions.  For example, you're car will run in open loop mode = when you=20 first start it, because there's no valid O2 sensor reading until it = warms=20 up.  Multi-wire heated O2 sensors have shortened this time = considerably=20 over the years.   I think most cars also run in open loop = mode=20 during full throttle operation.

Rusty    =

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