DIY_EFI Digest Sunday, 28 February 1999 Volume 04 : Number 136 In this issue: Re: EFI for Propane VSS and Transmission Output speed Re: Plasma Jet Ignition Propane EFI Re: Plasma Jet Ignition AMC? RE: VSS and Transmission Output speed Re: Propane EFI RE: EFI for Propane Re: Propane EFI Re: VSS and Transmission Output speed Re: Boost/Injectors...was "MAF..." Combustion - was Re: Propane EFI RE: Combustion - was Re: Propane EFI Re: EFI for Propane Re: Combustion - was Re: Propane EFI RE: Combustion - was Re: Propane EFI Re: Combustion - was Re: Propane EFI Re: Combustion - was Re: Propane EFI Re: EFI for Propane Re: EFI for Propane Re: Propane EFI Re: EFI for Propane Re: EFI for Propane EMI - more junkyard EFI, MAF & turbos: Update See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: FHPREMACH@xxx.com Date: Sat, 27 Feb 1999 05:20:54 EST Subject: Re: EFI for Propane In a message dated 2/26/99 1:52:29 PM Pacific Standard Time, ScottyCBoy@xxx.com writes: << I've got a question or two: Has anyone though about or attempted designind an EFI system for Propane/Butane fuel. I would think that liquid propane entering an intake manifold at 300 PSI at -80 degrees or whatever it boils at would do wonders to lower intake temps, plus with a stoich ratio nearing that of Gasoline and an Ocatne rating of 130 seems like it would be an ideal fuel for super high performance turbo charged engines.. Not to mention the fact that all those EPA CARB guys would love Propane's low emmision exhaust gasses. Has anyone found an electronic fuel injector capable of withstanding the high pressures and low temperatures for such a setup? Thanks! >> I recall someone at a college had done that with a Briggs and Stratton motor. Sent a letter to the list some time ago, Maybe it is still availible. Fred ------------------------------ From: "Bruce Plecan" Date: Sat, 27 Feb 1999 09:01:27 -0500 Subject: VSS and Transmission Output speed On a 8625 pcm, there are two connections, one labeled VSS, which is vehicle speed sensor, and a second one labeled transmission output speed, they both feed from the Vehicle Speed Signal Bufffer to the PCM. Can anyone splain this to me?. Is this just a way of checking for transmission "slippage". Anyone happen to know what this 5v signal should be?. ie square, 4,000ppm?. Thanks Bruce ------------------------------ From: Padgett 0sirius Date: Sat, 27 Feb 1999 09:44:43 -0500 Subject: Re: Plasma Jet Ignition Is this better ? Am using Eudora Pro 3.05 and there is no "HTML" reference. Have selected "Discard styles before sending text" & hope that does it. At 06:16 PM 2/26/99 -0600, you wrote: >Hi Padgett, glad you decided to join. One more thing, please turn off >html formatting when mailing to the list. Lots of people can't read it. A. Padgett Peterson, P.E. Cybernetic Psychophysicist Anti-Virus, Cryptographics, & Antique Radio Researcher http://www.freivald.org/~padgett/index.html mailto:padgett@xxx.5 Key on request ------------------------------ From: bob@xxx.com (Robert Harris) Date: Sat, 27 Feb 1999 17:19:02 GMT Subject: Propane EFI Biggest problem with propane EFI is that it's boiling point is all over the map - from not at -42~ to 175+ at 100f~. This implies pumping to a high pressure, special unobtanium injectors ( gasoline ~50 to 75~ psi) and lots of high pressure gas in the engine compartment. That's the bad news. The good news is if you are a fangler, you can tell the tank company to suck off. Seems like a blend of liquid propane and butane about 50/50 is a direct replacement for freon 12. Yet did know that propane is an established and excellent refrigerant? Hummm Duh - that means any small auto a/c pump and coils can be used effectively as a pressurizing system - using a stock tank without exotic in tank pump. That ought to give you a bunch of dead presidents to play with. Next, unless I am sadly missing the point, the only advantage of liquid propane over gaseous propane is the latent heat of vaporization. Gaseous propane introduced such that it can fully blend results in a homogeneous mixture that's incredibly smooth and even burning. This premixed gas is why when by weight is much less than gasoline yet delivers within 10% of the milage of gasoline. Direct port injection will not carry much of the fuel into the chamber liquid -44F bp and forfeit the homogeneous mixture advantage. One alternative for fangling is to salvage a conventional water heated vaporizer and submit it to fangle torture. Remove the water jacketing. Machine the upper chamber off. Plumb the high pressure let down valve at one end of an A/C coil and the low pressure end at the other. Stick the A/C coil in the intake - either the air box NA or as an aftercooler turbo'd. Since the only reason for the water to add enough heat to keep the vaporizer from freezing, if the coil is large enough (not hard) it does that ok. BUT you now get FREE charge cooling without having to obtain unobtainium high pressure injectors. Then, you can use the Ford IAC, a pulse width modulated solenoid valve to control the flow of vapor propane with nice simplicity without forfeiting the cooling of "liquid" injection. For a turbo, you could go one step further yet. You could hook up a small AC pump at the low pressure side and as the boost pressure goes positive, clutch it on, greatly increasing the flow of tank pressure liquid propane thru the coil and dump the pressurized gas back into the tank after running thru a condenser. How cold would you like your fries sir? Does an aftercooler core trying real hard to reach -44f~ tickle any fancies, combined with the excellent performance of homogeneous vapor? Thought not. On octane, reality check. According to "Knocking Characteristics of Pure Hydrocarbons" API Research Project 45 Critical Compression Ratios 600rpm/212f 600rpm/350f 2000rpm/212f 2000rpm/350f Propane 12.2/+6g 8.8/+1g 9.0/100 6.65/96 Toluene 15.0/+8g 11.5/+4.9g 13.5/+5.5g 9.0/+2.8g Propane R = +1.6g M=97 Toluene R= +5.8g M=+.3 Blend R = 124 Blend M = 112 No such ting as octane over 100 since 100 is pure octane. Knock resistance is measured as pure octane (100) + grams TEL added to pure octane to have equivalent knock. Critical Compression Ratio is the C/R that knock is induced on that fuel at that RPM and at that jacket temperature on the test engines. Considered by API/ASME to be a much better predictor of engine performance than R/M Note that the effective octane of propane is significantly lower than toluene - - the most common high octane fuel component in former street gas and now aviation and racing gas. And its research blending octane is not 130 but only 124. (Blending Octane is another subject ). Note also, that as the temperature goes up, the effective octane of propane drops radically. 1963 Ford C-600 Prison Bus Conversion "Home" 1971 Lincoln Continental 460 "Christine" 1972 "Whale" Mustang awaiting transplant 1978 Dodge Long Bed Peeek Up "Bundymobile" Habaneros - not just for breakfast anymore ------------------------------ From: Bryan Moody Date: Sat, 27 Feb 1999 12:36:23 -0500 Subject: Re: Plasma Jet Ignition Much better. thanks! - -- Bryan Moody ------------------------------ From: "David A. Cooley" Date: Sat, 27 Feb 1999 12:42:02 -0500 Subject: AMC? Hello all, Wondering if anyone knows what EFI system (computer, processor etc) was used on the 1987 AMC/Renault GTA (2.0L 4cyl.) Thanks, Dave =========================================================== David Cooley N5XMT Internet: N5XMT@xxx.net Packet: N5XMT@xxx. Member #7068 I am Pentium of Borg...division is futile...you will be approximated. =========================================================== ------------------------------ From: Don.F.Broadus@xxx.com Date: Sat, 27 Feb 1999 13:29:36 -0600 Subject: RE: VSS and Transmission Output speed It could be part of the ABS input. > -----Original Message----- > From: Bruce Plecan [SMTP:nacelp@xxx.net] > Sent: Saturday, February 27, 1999 8:01 AM > To: DIY_EFI > Subject: VSS and Transmission Output speed > > On a 8625 pcm, there are two connections, one labeled VSS, which is > vehicle > speed sensor, and a second one labeled transmission output speed, they > both feed from the Vehicle Speed Signal Bufffer to the PCM. Can anyone > splain this to me?. Is this just a way of checking for transmission > "slippage". > Anyone happen to know what this 5v signal should be?. ie square, > 4,000ppm?. > Thanks > Bruce ------------------------------ From: "Jeffrey T. Birt" Date: Sat, 27 Feb 1999 14:16:53 -0600 Subject: Re: Propane EFI Yeah I've heard of people using it to replace freon. I've also heard of AC systems BLOWING UP because of it. Try it at your own risk. Just my two-cents. Jeff Birt Robert Harris wrote: > The good news is if you are a fangler, you can tell the tank company to suck > off. Seems like a blend of liquid propane and butane about 50/50 is a direct > replacement for freon 12. Yet did know that propane is an established and > excellent refrigerant? Hummm Duh - that means any small auto a/c pump and > coils can be used effectively as a pressurizing system - using a stock tank > without exotic in tank pump. That ought to give you a bunch of dead > presidents to play with. > ------------------------------ From: Marc Piccioni Date: Sat, 27 Feb 1999 13:19:26 -0700 Subject: RE: EFI for Propane Have you considered the possibility of have the injectors freezing ? As the propane expands it removes a lot of heat from the surrounding area, this is why the propane expansion chamber is always heated with engine coolant. - ---------- From: Raymond C Drouillard[SMTP:cosmic.ray@xxx.com] Sent: February 25, 1999 11:57 PM To: diy_efi@xxx.edu Subject: Re: EFI for Propane >....What about cooling the lpg to a point where its liquid, then we >could use regular efi injectors, we dont have to create a box that must >regulate injection time for the variable pressure that temperature is doing > >for lpg fuel pressure.Can a Lucas disc type injector cope with the >pressure? >What about two injectors in series?One ontop of the other? >I have been thinking of just pumping twostroke oil into the lpg tank >to get a mix. >Espen Hilde I was thinking of feeding the liquid into the injecter at perhaps 330 PSI, and using something similar to a diesel injecter on the other end that opens at 300 PSI. That way the injecter would see a 30 PSI difference in pressures, and be dealing with a warm liquid. The standard injecter would be used as a valve, and the propane would vaporize once it leaves the injecter (regulater or whatever you want to call it). I would rather have an injecter that can handle the 300 PSI without such a jerry rig, though. Ray ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com/getjuno.html or call Juno at (800) 654-JUNO [654-5866] begin 600 WINMAIL.DAT M>)\^(@(4`0:0" `$```````!``$``0>0!@`(````Y 0```````#H``$-@ 0` M`@````(``@`!!) &`& !```!````# ````,``# #````"P`/#@`````"`?\/ M`0```&$`````````@2L?I+ZC$!F=;@#=`0]4`@````!D:7E?969I0&5F:3,S M,BYE;F``,P`0`` M`"(```!D:7E?969I0&5F:3,S,BYE;F5]E9FE 969I,S,R+F5N9RYO M:&EO+7-T871E+F5D=2<``@$+, $````G````4TU44#I$25E?149)0$5&23,S M,BY%3D-H;%R5NSD81TKZ<1$535 `````>`!X,`0````4```!33510```` M`!X`'PP!````& ```&UP:6-C:6]N:4!A='1C86YA9&$N;F5T``,`!A W@2LV M`P`'$-\$```>``@xxx.4TE$15)%1%1(15!/4U-) M0DE,25193T9(059%5$A%24Y*14-43U)31E)%15I)3D<_05-42$504D]004Y% M15A004Y$4TE44D5-3U9%4T%,3U1/1DA%051&4D]-``````(!"1 !````:@4` M`&8%``"+"0``3%I&=:))3I#_``H!#P(5`J@%ZP*#`% "\@D"`&-H"L!S970R M-P8`!L,"@S(#Q0(`<')"<1'B?,C4U`H '"H$-L0M@;F0A@( 6@ M1P"!!($)@"!T:!RP!Z\0N 9R _%+ $(!W#`V"E"K!N'+!E>"%Q9 0@/1Z (!>@!& +!VQ! `?< 0@=V@> MH/\A#P"0`B =`!& !M $D"7"^0= =V$3L"-S'9$#\!W ?R&P&J +@!RP!: & M\ !P=(XN"H4*BQYP,3@P`M'@:2TQ-#0-\ S0+%-Y"UDQ-@J@`V 3T!_ (+XM M+G<*ARTK## M]D8#8?XZ+WXM]@R"!_ H@ 1@(@#P($,@1"21`Q +8 L@0%M3 M3510.@6@H!G0)6 Q.3L0`3KP,3HU-R!037,V'S M5&\X7S)K)-!Y,E\-P&E 0!$: MX#(NR2F!+F\ED&\M$\ HX9E L&1U.]\W+G5B'Z*+/?\R;&5$4$5&22 0G06Q M4"%4*G\K@S,V+/>G&]4M]@J%/BY*X5<1@'\%0 &@"& %0"GR('(=PFSZ<$PQ M;R+A'@`+@ 5 )@"O'7$B,00@'G!Q- !D)6*7"? E\$=6/@6@=6P=H/9U$; B M86=/L K!0!$?>/\E8$[P/\ "(1[E3. %`"C26R+A!N!X';$CH6U/\'3_2F90 M-%+A'X0G8E5@!X!&H_T=PG8*P 0)&'W'R(CH1/1< 20(Z!78@0` M?PJ%4= @xxx.1(O!,>'5C800@)- $\!VP>?]8 M(!]W'0%=(2DS'<%*9E<6YC]*9DLI='=,X!^("X#G)% &<0>0/T\AD0(A(6#_ M'K(=PB,@xxx.P26!;FL@"IF/FQ%+16@xxx.1O M)RA4AG1!>)%+,67_'* %P!S2*'!-45)R!T!G\_\# MD6\G4W-<< .@$8 B`%;A_QW"=K4I(TN2)& 1< J%(O!O'Z D@!Z@!1!G)6(( M8&?N:"IM,S%';%^13Y)?DV_;E&T*A5DH)BSF90C MQ$H+-9%OHF@xxx.<\+QM; J%7;*'PIQV*"OA`"D@ M-C4T+4I5$$Y/(%N@PC4X-MXV-@9'WRSW%6(R$K!)[046P0"EH ```P`0$ `` M```#`!$0`0```$ `!S" 8)4DCF*^`4 `"#" 8)4DCF*^`1X`/0`!````!0`` +`%)%.B `````G#(` ` end ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Sat, 27 Feb 1999 13:26:35 -0700 Subject: Re: Propane EFI >Biggest problem with propane EFI is that it's boiling point is all over the >map - from not at -42~ to 175+ at 100f~. This implies pumping to a high >pressure, special unobtanium injectors ( gasoline ~50 to 75~ psi) and lots of >high pressure gas in the engine compartment. That's the bad news. If you wanna get serious about figuring out exactly what is going on here, there are charts of the thermo properties of propane in the ASHRAE manual. Analogous to steam tables, use 'em the same way to figure pressure v. temp v. enthalpy, boiling point at a given pressure, etc. Boiling point at 1 atm. (sea level) is about -38 F. Don't remember critical point T & P off the top of the noggin. > >The good news is if you are a fangler, you can tell the tank company to suck >off. Seems like a blend of liquid propane and butane about 50/50 is a direct >replacement for freon 12. Yet did know that propane is an established and >excellent refrigerant? Only in refineries, where the fact that it burns so well is no different than everything else in the joint! Hummm Duh - that means any small auto a/c pump and >coils can be used effectively as a pressurizing system - using a stock tank >without exotic in tank pump. That ought to give you a bunch of dead >presidents to play with. All you need to get pressure out of the storage tank reliably is a little bit of heat under it, and a bottom feed outlet line. All (prolly more) pressure than you could ever want that way. > >Next, unless I am sadly missing the point, the only advantage of liquid >propane over gaseous propane is the latent heat of vaporization. Gaseous >propane introduced such that it can fully blend results in a homogeneous >mixture that's incredibly smooth and even burning. This premixed gas is why >when by weight is much less than gasoline yet delivers within 10% of the >milage of gasoline. Direct port injection will not carry much of the fuel >into the chamber liquid -44F bp and forfeit the homogeneous mixture advantage. But the problem, and the reason that propane engines are down on power is that vaporized propane, with its lower (44 vs. about 114) atomic weight, displaces about 2.5 times as much oxygen as vaporized gasoline. So--like always--less oxygen, less power! > >One alternative for fangling is to salvage a conventional water heated >vaporizer and submit it to fangle torture. Remove the water jacketing. >Machine the upper chamber off. Plumb the high pressure let down valve at one >end of an A/C coil and the low pressure end at the other. Stick the A/C coil >in the intake - either the air box NA or as an aftercooler turbo'd. Since the >only reason for the water to add enough heat to keep the vaporizer from >freezing, if the coil is large enough (not hard) it does that ok. BUT you now >get FREE charge cooling without having to obtain unobtainium high pressure >injectors. Try running the calcs here. There's more than enough heat of vaporization to cool the intake charge below the boiling point of the propane, IF the manifold were not LONG PAST saturated with propane vapor. (WHICH IT COULD NEVER BE!) (meaning no more would evaporate!) Dat's why you need heat. But where else is there heat available? Compression stroke. So flash SOME (20%) of the propane into the intake, and use the latent heat from that to cool the air charge to the point where it is saturated with propane, plus to chill the rest of the liquid propane, while it is still at high (300 psi) pressure to whatever that temp is. reduce the rest of the propane down to a normal (4 bar??) fuel rail pressure with a regulator. Let whatever propane flashes from this process vent out of the rails through a float vent and go into the manifold too. Now, you have liquid propane at about 60 psi above the manifold pressure in the fuel rails, and at whatever its boiling point is at that pressure. So inject it into the ports through conventional injectors, which will atomize it decently, if NOT well, and most of the rest of the latent heat will absorb heat during the compression stroke, thus reducing compression work, cooling things down, and increasing net output somewhat. Big hitch here is--you do NOT want to reduce temp at the time of ignition (TDC) to the point where a stoich amount of ANY fuel in the chamber would have a higher (theoretical) partial pressure than that particular fuel's saturation pressure at the TDC temp. and volume--Cuz it will never get there! If you try to get past the saturated fuel vapor condition, it just WILL NOT happen--part of the fuel will still be liquid when the spark goes off, cuz there wuz never enough heat AVAILABLE to vaporize it. In case you hadn't guessed already, this is why alky fueled engines are always soggy and hard to get to light--the evaporation of the alky OVERCOOLS the charge and compression stroke to such a point that: first it is tough to get a saturated fuel vapor pressure condition at TDC which is a rich enough mixture to be above the LFL, and second, the remaining fuel droplets are trying to quench the flame front! I suspect that a run through the numbers with propane might show the same sort of problems as with alky--unless you add enough heat to vaporize most of it from the water jacket, like has always been done. And this little discussion has not even addressed what to do with the propane vapor from the fuel rails during a hot soak! Regards, Greg ------------------------------ From: "Jon Fedock" Date: Sat, 27 Feb 1999 15:43:17 -0500 Subject: Re: VSS and Transmission Output speed Hmmm....Just a guess here, but maybe a 4-wheel drive? One sensor in Transfer case and one in tranny...That way it could know if it was in 4-low? Jon - -----Original Message----- From: Bruce Plecan To: DIY_EFI Date: Saturday, February 27, 1999 9:08 AM Subject: VSS and Transmission Output speed |On a 8625 pcm, there are two connections, one labeled VSS, which is vehicle |speed sensor, and a second one labeled transmission output speed, they |both feed from the Vehicle Speed Signal Bufffer to the PCM. Can anyone |splain this to me?. Is this just a way of checking for transmission |"slippage". |Anyone happen to know what this 5v signal should be?. ie square, 4,000ppm?. |Thanks |Bruce | | ------------------------------ From: d houlton x0710 Date: Sat, 27 Feb 1999 14:19:23 -0700 (MST) Subject: Re: Boost/Injectors...was "MAF..." ECMnut@xxx.com wrote: > > Dan, I missed the beginning.. > What is the engine/application? > Mike V > > > It's an internal wastegate and I don't have an adjustable boost controller > > of any kind so the signal line is a short 3" piece of 1/4" hose from the > > output of the compressor scrollhousing to the actuator. Not much of a > > restriction there I think. > It's an Isuzu 2.6l 4 cylinder. The turbo is an IHI off an Isuzu 2.0l, but with a larger compressor section from an '88 TurboCoupe. - --Dan ------------------------------ From: Padgett 0sirius Date: Sat, 27 Feb 1999 18:14:57 -0500 Subject: Combustion - was Re: Propane EFI Uh folks, as far as energy per gallon is concerned, gas is gas, it is all the same. What octane measures is how fast it burns and to a lesser extent ignition pressure. Higher octane gives slower burning & more resistance to "spontaneous combustion". The secret to a SI engine is controlled combustion. Since the pressure rise is not instantaneous mechanical spark advance is needed. Since the burn rate varies with chamber pressure, you also need vaccuum advance. The goal is for peak cylinder pressure by about 10 degrees ATDC (varies a bit with engine geometry). This will vary for any fuel used. Might I suggest review of chapter 1 "Combustion" in Ricardo's "The High Speed Internal Combustion Engine" ? Is better than Obert. A. Padgett Peterson, P.E. Cybernetic Psychophysicist Anti-Virus, Cryptographics, & Antique Radio Researcher http://www.freivald.org/~padgett/index.html mailto:padgett@xxx.5 Key on request ------------------------------ From: Don.F.Broadus@xxx.com Date: Sat, 27 Feb 1999 17:40:42 -0600 Subject: RE: Combustion - was Re: Propane EFI Are you the same Padgett that had articles in several Pontiac magazines ? > -----Original Message----- > From: Padgett 0sirius [SMTP:padgett@xxx.net] > Sent: Saturday, February 27, 1999 5:15 PM > To: diy_efi@xxx.edu > Subject: Combustion - was Re: Propane EFI > > Uh folks, as far as energy per gallon is concerned, gas is gas, it is > all the same. What octane measures is how fast it burns and to a lesser > extent ignition pressure. Higher octane gives slower burning & more > resistance to "spontaneous combustion". The secret to a SI engine is > controlled combustion. Since the pressure rise is not instantaneous > mechanical spark advance is needed. Since the burn rate varies with > chamber pressure, you also need vaccuum advance. The goal is for peak > cylinder pressure by about 10 degrees ATDC (varies a bit with engine > geometry). This will vary for any fuel used. > > Might I suggest review of chapter 1 "Combustion" in Ricardo's "The High > Speed Internal Combustion Engine" ? Is better than Obert. > A. Padgett Peterson, P.E. Cybernetic Psychophysicist > Anti-Virus, Cryptographics, & Antique Radio Researcher > http://www.freivald.org/~padgett/index.html > mailto:padgett@xxx.5 Key on request ------------------------------ From: Raymond C Drouillard Date: Fri, 26 Feb 1999 19:31:18 -0500 Subject: Re: EFI for Propane Read it again. My idea is to use the injecter as a valve, and let the fuel expand to a vapor inside the throttle body. The pump would pressurize the propane to arount 330 PSI. This would be fed into the input side of the injecter. The output side would be connected to something similar to a diesel injecter, which is a valve that opens at a specific pressure. If it is set to 300 PSI, the injecter will "see" a pressure differential of 30 PSI, and will be fed with relatively warm propane. The valve at the end (a pressure regulater) will be exposed to the cold. It will be fed warm liquid, which will vaporize a few millimeters away from the output. There will be no water vapor at the valve itself, so ice shouldn't be a problem. Since my Holley Pro-Jection system is a throttle body injection system, injecting the propane right below the throttle body will work well. Doing it this way will allow the air and propane to mix well before reaching the intake valves. Ray On Sat, 27 Feb 1999 13:19:26 -0700 Marc Piccioni writes: >Have you considered the possibility of have the injectors freezing ? As the >propane expands it removes a lot of heat from the surrounding area, this is >why the propane expansion chamber is always heated with engine coolant. > >---------- >From: Raymond C Drouillard[SMTP:cosmic.ray@xxx.com] >Sent: February 25, 1999 11:57 PM >To: diy_efi@xxx.edu >Subject: Re: EFI for Propane > > >>....What about cooling the lpg to a point where its liquid, then we >>could use regular efi injectors, we dont have to create a box that must >>regulate injection time for the variable pressure that temperature isdoing >> >>for lpg fuel pressure.Can a Lucas disc type injector cope with the pressure? >>What about two injectors in series?One ontop of the other? >>I have been thinking of just pumping twostroke oil into the lpg tank to get a mix. >>Espen Hilde > >I was thinking of feeding the liquid into the injecter at perhaps 330 >PSI, and using something similar to a diesel injecter on the other end >that opens at 300 PSI. That way the injecter would see a 30 PSI >difference in pressures, and be dealing with a warm liquid. The standard >injecter would be used as a valve, and the propane would vaporize once it >leaves the injecter (regulater or whatever you want to call it). > >I would rather have an injecter that can handle the 300 PSI without such >a jerry rig, though. > >Ray ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com/getjuno.html or call Juno at (800) 654-JUNO [654-5866] ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Sat, 27 Feb 1999 18:09:34 -0700 Subject: Re: Combustion - was Re: Propane EFI >Uh folks, as far as energy per gallon is concerned, gas is gas, it is >all the same. Not at all true--each individual hydrocarbon has its own heat of combustion. Generally, higher octane "rated" fuels tend to have slightly lower heats of combustion than lower octane rated fuels. Diesel, for instance, has a somewhat higher heat of combustion than a typical gasoline blend. With mixtures to the rich side of lambda = 1, some hydrocarbons will burn "hydrogen first" selectively more readily than others will, thus giving a higher heat of combustion per unit of oxygen present. What octane measures is how fast it burns and to a lesser >extent ignition pressure. Higher octane gives slower burning & more >resistance to "spontaneous combustion". The secret to a SI engine is >controlled combustion. Since the pressure rise is not instantaneous >mechanical spark advance is needed. Since the burn rate varies with >chamber pressure, you also need vaccuum advance. The goal is for peak >cylinder pressure by about 10 degrees ATDC (varies a bit with engine >geometry). This will vary for any fuel used. All true. > >Might I suggest review of chapter 1 "Combustion" in Ricardo's "The High >Speed Internal Combustion Engine" ? Is better than Obert Personally, I feel that Obert is a bit more up to date than Ricardo, especially his more recent edition. Regards, Greg ------------------------------ From: Padgett 0sirius Date: Sat, 27 Feb 1999 21:35:33 -0500 Subject: RE: Combustion - was Re: Propane EFI Never have run into anyone else with the same given name - did write quite a bit in the eighties before disappearing into a black hole. At 05:40 PM 2/27/99 -0600, you wrote: >Are you the same Padgett that had articles in several Pontiac magazines ? > >> -----Original Message----- >> From: Padgett 0sirius [SMTP:padgett@xxx.net] >> Sent: Saturday, February 27, 1999 5:15 PM >> To: diy_efi@xxx.edu >> Subject: Combustion - was Re: Propane EFI >> >> Uh folks, as far as energy per gallon is concerned, gas is gas, it is >> all the same. What octane measures is how fast it burns and to a lesser >> extent ignition pressure. Higher octane gives slower burning & more >> resistance to "spontaneous combustion". The secret to a SI engine is >> controlled combustion. Since the pressure rise is not instantaneous >> mechanical spark advance is needed. Since the burn rate varies with >> chamber pressure, you also need vaccuum advance. The goal is for peak >> cylinder pressure by about 10 degrees ATDC (varies a bit with engine >> geometry). This will vary for any fuel used. >> >> Might I suggest review of chapter 1 "Combustion" in Ricardo's "The High >> Speed Internal Combustion Engine" ? Is better than Obert. >> A. Padgett Peterson, P.E. Cybernetic Psychophysicist >> Anti-Virus, Cryptographics, & Antique Radio Researcher >> http://www.freivald.org/~padgett/index.html >> mailto:padgett@xxx.5 Key on request > > A. Padgett Peterson, P.E. Cybernetic Psychophysicist Anti-Virus, Cryptographics, & Antique Radio Researcher http://www.freivald.org/~padgett/index.html mailto:padgett@xxx.5 Key on request ------------------------------ From: Padgett 0sirius Date: Sat, 27 Feb 1999 22:07:50 -0500 Subject: Re: Combustion - was Re: Propane EFI My Obert is second edition, eighth printing (1958). Is there a more recent one/better one ? BTW is there a preferred PROM reader/writer ? Am somewhat cost sensitive as this is a hobby. Suspect a 32 pin is adequate or is a 40 necessary for more modern GM (my latest is a '92, toy is '86 C3). Last time I pulled on apart seems to have been in 1983. Thanks for the help. A. Padgett Peterson, P.E. Cybernetic Psychophysicist Anti-Virus, Cryptographics, & Antique Radio Researcher http://www.freivald.org/~padgett/index.html mailto:padgett@xxx.5 Key on request ------------------------------ From: "David A. Cooley" Date: Sat, 27 Feb 1999 22:27:17 -0500 Subject: Re: Combustion - was Re: Propane EFI At 10:07 PM 2/27/99 -0500, you wrote: >My Obert is second edition, eighth printing (1958). Is there a more recent >one/better one ? > >BTW is there a preferred PROM reader/writer ? Am somewhat cost sensitive as >this is a hobby. Suspect a 32 pin is adequate or is a 40 necessary for more >modern GM (my latest is a '92, toy is '86 C3). Last time I pulled on apart >seems to have been in 1983. I've got the Needhams PB-10, $129.95, ISA card and 40 pin ZIF... Does most all EPROMs, EEPROMS, FLASH etc. =========================================================== David Cooley N5XMT Internet: N5XMT@xxx.net Packet: N5XMT@xxx. Member #7068 I am Pentium of Borg...division is futile...you will be approximated. =========================================================== ------------------------------ From: "Clarence L.Snyder" Date: Sat, 27 Feb 1999 22:52:23 -0500 Subject: Re: EFI for Propane > The pump would pressurize the propane to arount 330 PSI. This would be > fed into the input side of the injecter. The output side would be > connected to something similar to a diesel injecter, which is a valve > that opens at a specific pressure. If it is set to 300 PSI, the injecter > will "see" a pressure differential of 30 PSI, and will be fed with > relatively warm propane. You don't need a pump if you take propane off the bottom of the tank - called liquid withdrawal. This is standard for automotive propane systems. It IS liquid when it hits the "evaporator" - you know, that water heated thingamagig used on "carbed" propane units. The pressure varies with tank(vapour) temperature - not with fuel level, so it would not be hard to calibrate an EFI to use liquid propane. The problem I see is getting an injector to do the deed. Mabee try the electronic controlled injectors from something like a Ford Powerstroke or electronically managed Cummins or Mack. Not sure how they work, or if they require lubrication. Size the injector to flow 15% more fuel than you would use for gasoline to start because energy density of propane is about that much lower (If I remember correctly - my propane days go back a little while) The big problem, at least here in Ontario, would be getting the bugger certified so you would be allowed to re-fuel it. Lots of little things you would not think of, I'm sure. ------------------------------ From: Jim Davies Date: Sat, 27 Feb 1999 20:51:27 -0800 (PST) Subject: Re: EFI for Propane On Sat, 27 Feb 1999, Clarence L.Snyder wrote: > varies with tank(vapour) temperature - not with fuel level, so it would > not be hard to calibrate an EFI to use liquid propane. The problem I see > is getting an injector to do the deed. Mabee try the electronic > controlled injectors from something like a Ford Powerstroke or > electronically managed Cummins or Mack. Not sure how they work, or if > they require lubrication. Size the injector to flow 15% more fuel than > you would use for gasoline to start because energy density of propane is > about that much lower (If I remember correctly - my propane days go back > a little while) Why not check out what mopar did with their propane EFI setup. IIRC, Ford has a similar setup. ------------------------------ From: Tom Sharpe Date: Sat, 27 Feb 1999 23:25:03 -0600 Subject: Re: Propane EFI Just another couple of out of the box ideas. Build a E-mechanical type injector like the old Rochesters FI that use a tapered rod and jet, kind of like a slide valve Motorcycle carb. Drive the movement with an IAC motor or other small stepper like for a disk drive. Dual fuel the motor - all the time or just under boost. Drop in the propane with notrous solenoids/jets..... and keep the EFI running gasoline. Tom S. ------------------------------ From: "Clarence L.Snyder" Date: Sun, 28 Feb 1999 00:23:54 -0500 Subject: Re: EFI for Propane Why not check out what mopar did with their propane EFI setup. IIRC, Ford has a similar setup. Vapour Phase injection is used on these vehicles - designed and built just down the road and around the corner from me in Bridgeport (Kitchener) Ontario. ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Sat, 27 Feb 1999 22:53:23 -0700 Subject: Re: EFI for Propane >> The pump would pressurize the propane to arount 330 PSI. This would be >> fed into the input side of the injecter. The output side would be >> connected to something similar to a diesel injecter, which is a valve >> that opens at a specific pressure. If it is set to 300 PSI, the injecter >> will "see" a pressure differential of 30 PSI, and will be fed with >> relatively warm propane. > >You don't need a pump if you take propane off the bottom of the tank - >called liquid withdrawal. This is standard for automotive propane >systems. It IS liquid when it hits the "evaporator" - you know, that >water heated thingamagig used on "carbed" propane units. The pressure >varies with tank(vapour) temperature - not with fuel level, so it would >not be hard to calibrate an EFI to use liquid propane. The problem I see >is getting an injector to do the deed. Mabee try the electronic >controlled injectors from something like a Ford Powerstroke or >electronically managed Cummins or Mack. Not sure how they work, or if >they require lubrication. Size the injector to flow 15% more fuel than >you would use for gasoline to start because energy density of propane is >about that much lower (If I remember correctly - my propane days go back >a little while) >The big problem, at least here in Ontario, would be getting the bugger >certified so you would be allowed to re-fuel it. Lots of little things >you would not think of, I'm sure. - ---------------------------------------- Lower heat of combustion for propane is 19,768 BTU/lb. Lower heat of combustion for iso-octane is 19,065 BTU/lb. Reason propane fueled engines are down on power is largely due to greater displacement of intake air by vaporized fuel than what happens with gasoline, due to lower molecular weight of propane compared to gasoline. No latent heat effects in inlet tract or during compression stroke with (pre-vaporized) propane are the other effects. Also slightly less heat of combustion at stoich for a given mass flow of air with propane, but certainly not 15%. Stoich A/F ratio for propane is 15.7:1 (by weight). Flow through an injector will vary with the square root of the pressure difference across the injector. MASS Flow through an injector will ALSO vary with the square root of the density of the liquid going through it. IF NO FLASHING OCCURS! If you get any flashing (into vapor) in the injector, all quantitative bets on flow rate are off (except that it will be lower than with no flashing), but MORE IMPORTANTLY, the flashing WILL erode injector parts pretty quickly if they are not made of the right stuff! For decent durability with flashing going on, you would likely need 400 series Stainless at a minimum, or maybe carbide or stellite for parts in contact with the flashing. Regards, Greg ------------------------------ From: Tom Sharpe Date: Sun, 28 Feb 1999 00:08:55 -0600 Subject: EMI - more junkyard Last nite I unwrapped a junk yard Ford Harness. Couple if items poped out. There were two wires wrapped around each other that went to the first plug on the harness nearest the CPU. It branches at 4" and is another 12" long. The spirals are about 3 turns for 2" and it's loosely wrapped. You EE boys will know what this is for. >From 1' to 2.5 ', the main harness is wrapped in tin foil, then some kind of woven heat blanket, (looks like kevlar) then the standard electrical tape. Three wires from the main plug, starting about 3' out, are wrapped in foil, then tape, and under the foil is a lot of stranded/woven ground wires. they also seem to be wrapped around the main harness under the tin foil Anything interesting here?? Everyone should try this just to learn how to build your own harness,,,, at least how to wrap it in tape... Tom S ------------------------------ From: Daniel Houlton Date: Sat, 27 Feb 1999 23:26:48 -0700 (MST) Subject: EFI, MAF & turbos: Update I was able to do some more testing on my turbo install. I had asked before about the problem I was seeing where the mixture under boost would go full lean (drop completely off the A/F meter) when the ECM went to open-loop under boost when the WOT switch kicked in. I did some tests by diabling the WOT switch and it did indeed prevent the mixture from going full lean although it was no longer rich under heavy load or transient conditions. Makes sense I guess. Hooked the WOT switch back up and hooked up my multimeter to one of the fuel injectors to measure the duty cycle. At an idle of 850 rpm, the duty cycle was 2%. I then took it out on the freeway to see where the duty cycle reached 80% and 100% so I could better estimate how much more fueling I'm gonna need. I found some surprising things. First off was that WOT on the freeway did not cause the A/F ratio to go full lean like it had been before. At least not all the time. After a bit of testing I found that it only went full lean if I went to WOT (and the ECM went to open loop) while the rpms were *under* 3000. Over 3000 rpm and I could go to WOT and the mixture would stay rich all the way to 5000 rpm. This was the first time actually that I've been able to do a full throttle test to see where the max boost was as I hadn't hooked up the A/F meter before and didn't want to chance it. At this point, boost had stabalized at 9 psi and the injectors reached 100% duty cycle. 5000 rpm is also my peak horsepower so based on this and my stock 120 hp I was making about 190 hp. It looks like my injectors are a bit larger than I had thought. I had figured them at 21 lb/hr from some other sources but to flow 190 hp at 100% duty cycle they'd need to be about 26 lb/hr right? So I'm curious about that 3000 rpm mark. I was re-reading parts of my "Maximum Boost" book and I picked up on something I hadn't noticed before. My stock EFI is sequential port injection. According to Corky Bell, most (all?) seqential systems revert to non-sequential at 3000 rpm. Could this somehow be related to my WOT/full lean problem below 3K that I originally asked about? How can I tell if my EFI is indeed switching to non-sequential at 3K? thanks - --Dan ------------------------------ End of DIY_EFI Digest V4 #136 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".