DIY_EFI Digest Sunday, March 12 2000 Volume 05 : Number 100 In this issue: Re: Stratified Charge DI with EGR Re: Electronic Transmission Control Re: Stratified Charge DI with EGR (was: AFM measurement/backpressure) Re: Stratified Charge DI with EGR (was: AFM measurement/backpressure) Re: Stratified Charge DI with EGR (was: AFM measurement/backpressure) Re: AFM measurement/backpressure Re: Stratified Charge DI with EGR re: Crank trigger Re: Electronic Transmission Control Re: Stratified Charge DI with EGR Re: Stratified Charge DI with EGR See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Sun, 12 Mar 100 11:27:08 +0800 (WST) From: Bernd Felsche Subject: Re: Stratified Charge DI with EGR Mike writes: >At 11:59 PM 11/3/2000 +0800, Bernd Felsche wrote: >>Nor do you have stratified charge, or direct petrol injection one >>would assume. >mmm Are you implying this flybywire system is only direct injection, I Only in terms of running at WOT for low loads. >seem to recall volvo did something in that area early 80s but with >port injection - though they did claim high NOx reductions but I also >seem to recall they had a RF type ignition system duration which lasted >throughout the whole downstroke and part of upstroke... Probably extreme lean-burn with limited stratified charge. >>>In the event the engine is undersized/powered in comparison with an AFM >>>or MAP only setup then I suppose there is value - but are you saying with >>>this fly by wire that gradual pedal pressing under load by human can result >>>in wide open throttle plate by fly-by-wire. >>Up to a certain load, the engine operates in stratified-charge, lean >>burn, with the throttle wide open. Yes; a slight depression - i.e. >>low torque demand - results in WOT and a lean-burn cycle. >During this time whats the estimated EGR rate - approximate ? I would *guess* well in excess of 10% to achieve the desired NOx reductions. >>Note that the semantics of the pedal have changed; the driver >>determines the torque output, not the throttle opening. So if you >>keep pressing further, the engine will switch to homogenous >>operation and start throttling airflow - though you'd probably be >>hard-pressed to pick the transition. >mmm Understood. >>There are a few recent SAE papers; I don't have the funds to >>undertake all the research in that direction. Interesting though it >>may be. The first car to employ Bosch MED7 is the VW Lupo FSI. >do you know when this came out ? Isn't it Bosch that also did some 1999. In production this year. >work in early 80's on injection cycling with italian taxi cabs ? I don't know. >ie. Defer one injection from time to time but keep valve ops the same >on a 4stroke - the compressed air and heat from previous cycles was >enough on certain load ranges so the effect was not noticeable, saved >10-15% depending on the driver - narrow range of operation, no cat IIRC. Research into cylinder un-loading has been done for a long time. The need to keep the cylinders at operating temperature is of concern. There are mentions of the technology in the Bosch instruction books on Motronic (I think), etc, as well as other Bosch literature. >>Very much leaner than stoich - Bosch describes mixtures as lean as >>2.5; any leaner than 1.5 and stratified charge operation leads to >>soot formation; any leaner than 1.3 in homogenous mixture formation >>and ignition can fail, leading to a prohibited band of AFR which the >>engine management system must skip on the load transitions. >Sorry not with you on the numbers/terminology, in respect of AFR of 14.7 >to 1 stoich whats the 2.5, 1.5, 1.3 refer to in relation to AFR ? Those are lambda values where 1 == 14.7:1 AFR >>[In fact, the nature of the NOx storage cat (which stores the NOx as >>nitrates) requires that the engine periodically switch from >>lean-burn (LB) to homogenous so that sufficient CO is generated to >>allow the reduction to N2 and CO2 to take place. This switching is >>transparent to the driver as the ECU knows how to switch from LB and >>back without any change in engine torque.] >Did they use a deeply porous cat with rather more Pd or back to the >Rhodium/Platinum mix ? Don't know (yet) except that there's a separate NOx storage cat which stores the NOx emissions as "nitrates" on the surface until CO becomes available to allow the reduction. It appears that the ECU monitors the NOx levels downstream of the storage cat and switches out of LB when a threshold is reached. I don't know of further details of the chemistry. There's a tech-brief online and paper (1999-01-1284) available either for download or in a compendium "Gas Direct Injection Aftertreatment and Exhaust Aftertreatment Modeling" (SP-1455) on the SAE web site - search for MED7. - -- Real Name: Bernd Felsche Email: nospam.bernie@xxx.au http://www.perth.dialix.com.au/~bernie - Private HP - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sat, 11 Mar 2000 22:38:35 -0500 From: "C. Brooks" Subject: Re: Electronic Transmission Control I keep hearing/seeing people say that and I can't help but wonder. Have these people ever seen a dyno run with a turbo motor, be it a Buick 3.8 or a TT small block Chevy? I've seen several and unless the motors were race only, they made very large amounts of torque from the git go (Especially the TT V8's). I know of a TType here locally (D.C. Metro area) that makes 400Ft/Lb's at 2000 RPM. I've seen the dyno sheet and I've driven the car. I KNOW there are a few GN owners on this list, maybe one of you guys could to step in here and give us some more info on turbo 6's and 2004R's? Mike Kurtz at PMAC performance in Houston Texas would be an EXCELLENT person to discuss the 700R4 and 2004R with. He'll go over the pro's and con's of each transmission with you and spend as much time o the telephone as you need. PMAC's contact info is on the gnttype page. Charles Brooks Mid-Atlantic Speed Shop http://www.massmotorsports.com - ----- Original Message ----- From: Doug Dayson To: Sent: Saturday, March 11, 2000 12:07 PM Subject: Re: Electronic Transmission Control > If it's a combo with a "streetable converter" and a Super Ram'd BB for example > that makes that kind of torque off idle and you're runnin' slicks you're gonna > shock the trans at launch a lot harder than say a turbo six which makes it's > power higher up the rpm scale... > - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sat, 11 Mar 2000 16:46:19 +0000 From: Ade + Lamb Chop Subject: Re: Stratified Charge DI with EGR (was: AFM measurement/backpressure) At 19:32 11/03/00 +0800, Bernd Felsche wrote: >>That sounds incredible complecated... So presumuable there is no direct >>throttle cable... just a fly by wire pedal and ecu does the rest??? > >Throttle-by-wire. The driver sets the amount of torque required by >the position of the pedal. The ECU adjusts throttle, EGR (up to >70%), injection and ignition accordingly. That is what I thought you mean't. >The complication has its rewards; 15% less fuel consumption, partly >due to increased "volumetric efficiency" because the throttle is >often wide open... better find an updated abbreviation to replace >WOT! Cool... >The engine uses quantity-regulation at low load; the torque >developed depends on the amount of fuel injected. The amount of air >sucked in and ignition timing have little effect on torque. I thought you cannot use fuel/ignition to control torque o/p? Don't you end with exccesivly hot combustion? I can understand using EGR to control the torque o/p... the oposite of NOS injection :-) Ade - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sat, 11 Mar 2000 16:46:32 +0000 From: Ade + Lamb Chop Subject: Re: Stratified Charge DI with EGR (was: AFM measurement/backpressure) At 20:12 11/03/00, Mike (Perth, Western Australia) wrote: >At 07:32 PM 11/3/2000 +0800, Bernd Felsche wrote: > >>>That sounds incredible complecated... So presumuable there is no direct >>>throttle cable... just a fly by wire pedal and ecu does the rest??? >> >>Throttle-by-wire. The driver sets the amount of torque required by >>the position of the pedal. The ECU adjusts throttle, EGR (up to >>70%), injection and ignition accordingly. > >>The complication has its rewards; 15% less fuel consumption, partly >>due to increased "volumetric efficiency" because the throttle is >>often wide open... better find an updated abbreviation to replace >>WOT! > >Aye - I'm a bit perplexed here, are we talking diesel if not but, talking >petrol then I would have expected wide open throttle to consume more >petrol due to maintaining AFR ? You pump exhaust gas which has virtually no air in it into the inlet this reduces the power o/p without using petrol. >On the occasions I have wide open throttle on my vehicle I'll either >chew up huge amounts of fuel and/or leave rubber, but then my EGR is >minimal... Don't most current EGR systems use it to decrease emmisions more than anything else? >By the way whats does conventional "WOT" stand for ? Wide Open Throttle. Ade - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sun, 12 Mar 2000 15:08:27 From: "Mike (Perth, Western Australia)" Subject: Re: Stratified Charge DI with EGR (was: AFM measurement/backpressure) At 05:10 PM 11/3/2000 -0700, you wrote: >> >>>The complication has its rewards; 15% less fuel consumption, partly >>>due to increased "volumetric efficiency" because the throttle is >>>often wide open... better find an updated abbreviation to replace >>>WOT! >>> >It would be far more accurate to call this "decreased pumping losses" than >"increased volumetric efficiency". Yes thats a good point, because with higher EGR it takes energy to pump this inert gas around the system - I would have thought not that efficient. Decreased pumping losses for 'fresh air' would be spot on... :) mike - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sun, 12 Mar 2000 15:13:58 From: "Mike (Perth, Western Australia)" Subject: Re: AFM measurement/backpressure At 10:34 AM 12/3/2000 +0800, Bernd Felsche wrote: >>The resistance of the wire varies with its temperature, so one approach >>would be to measure the voltage required to hold the wire at a constant >>current. The more air flow you have at a given IAT, the cooler the wire >>gets. > >The current flow is directly related to the *mass* of the air >flowing in. That is generally sufficient to determine the amount of >fuel to inject. > >If you however desire air temperature - e.g. to adjust spark timing >or to alter the injection to allow for vapourization in cold air, >then you must sense this separately. Most hot wire AFM's I've seen include an air temp sensor but its wired into the wheatstone bridge which has the wire, on my Bosch AFM - its a little vertical tongue in the middle of the circular hot wire assembly, trouble is its not available as a separate signal to the ECU - just adjusts the AFM output signal appropriately. A separate one would be of some use - but with the performance level of my engine at moment its of marginal benefit... Rgds Mike Massen Ancient Sufi saying: "Should your God save you from adversity, choose another God" Pictures of site installation at Mendulong near Sipitang, Sabah (Malaysia) for container based RAPS... http://www.wantree.com.au/~erazmus Vehicle modifications on GMH Turbo, twin tyres, possible 175Kw at wheels Preliminary pictures at http://www.wantree.com.au/~erazmus/Twin_tyre_vehicle/ My editorial on twin-tyre opinion and good reference about tyres:- http://www.geocities.com/MotorCity/2195/ttyreopinion.html - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sun, 12 Mar 2000 15:19:42 From: "Mike (Perth, Western Australia)" Subject: Re: Stratified Charge DI with EGR At 11:27 AM 12/3/2000 +0800, Bernd Felsche wrote: >Mike writes: >>>Very much leaner than stoich - Bosch describes mixtures as lean as >>>2.5; any leaner than 1.5 and stratified charge operation leads to >>>soot formation; any leaner than 1.3 in homogenous mixture formation >>>and ignition can fail, leading to a prohibited band of AFR which the >>>engine management system must skip on the load transitions. > >>Sorry not with you on the numbers/terminology, in respect of AFR of 14.7 >>to 1 stoich whats the 2.5, 1.5, 1.3 refer to in relation to AFR ? > >Those are lambda values where 1 == 14.7:1 AFR Ah I see, you mean the lambda value is a multiplier, therefore 2.5 is really 2.5 * 14.7 = 36.75 - seems 'awfully' lean - blimey... ? >There's a tech-brief online and paper (1999-01-1284) available >either for download or in a compendium "Gas Direct Injection >Aftertreatment and Exhaust Aftertreatment Modeling" (SP-1455) on the >SAE web site - search for MED7. Tah, thanks for the reference, :) mike - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sun, 12 Mar 2000 15:25:03 From: "Mike (Perth, Western Australia)" Subject: re: Crank trigger At 08:50 AM 8/3/2000 -0600, "Clint S." wrote: >Thank you to those who responded . >I should have been a bit clearer when posting question . I have the nissan turbo motor originally equipped with a 3 pickup Hall sensor and (3) 120deg signal teeth and (90) 1 degree signal teeth . Rather than adapting this to my Accel DFI, I put in a normal magnetic pickup distributor and used a 1988 chev truck 4 wire EST igntion control module . The module hooked right up to the DFI and registered rpm . At this point the ignition and fuel should work, crank trigger is not used at this point . This is very different to the Nissan 3L turbo six in my car, are you talking an SR20 or a RB26DET variant with CS on the end of the cam ? Rgds :) mike - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sat, 11 Mar 2000 23:56:09 -0800 From: Doug Dayson Subject: Re: Electronic Transmission Control Hi Charles... Of course I'm aware of the power turbo motors can make...my reply was aimed at the original thread's discussion regarding a mild naturally aspirated SB Chevy... Later...Grumpy and I upped the ante somewhat to include "mild" GN's etc...the one running high 12's...not the ones running high 7's or however fast the fastest are these days...??? Of course turbo motors can be built hotter...and TT SB's never entered the discussion...yet anyway...(:>) So...my comparison regarding the shock on the trans was between a "mild" naturally aspirated 400ci or better V8 and a "mild" turbo six...remember that I specified a "mild" streetable converter so the turbo six would not have the turbo's humming at launch...so without the benefit of a higher rpm launch the "mild" 3.8 turbo six isn't gonna hit the trans as hard as the "mild" 400ci or bigger V8... As you know a "mild" naturally aspirated 400ci or better can easily make 400 ft/lbs around 2000 rpm too... The original discussion was between "stock" hi perf (GN...Vette etc) 700 series and 2004R's in mild streetable high 12 sec cars... Take care... Doug C. Brooks wrote: > I keep hearing/seeing people say that and I can't help but wonder. Have > these people ever seen a dyno run with a turbo motor, be it a Buick 3.8 or a > TT small block Chevy? > > I've seen several and unless the motors were race only, they made very large > amounts of torque from the git go (Especially the TT V8's). I know of a > TType here locally (D.C. Metro area) that makes 400Ft/Lb's at 2000 RPM. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sun, 12 Mar 100 18:29:24 +0800 (WST) From: Bernd Felsche Subject: Re: Stratified Charge DI with EGR Mike writes: >At 05:10 PM 11/3/2000 -0700, you wrote: >>>>The complication has its rewards; 15% less fuel consumption, partly >>>>due to increased "volumetric efficiency" because the throttle is >>>>often wide open... better find an updated abbreviation to replace >>>>WOT! >>It would be far more accurate to call this "decreased pumping losses" than >>"increased volumetric efficiency". >Yes thats a good point, because with higher EGR it takes energy to pump this >inert gas around the system - I would have thought not that efficient. >Decreased pumping losses for 'fresh air' would be spot on... Well, the EGR isn't actually pumped - it's vented according to the literature which only indicates a valve to regulate the amount of EGR. The manifold pressure is also sensed, probably so that the amount and rate of EGR, as much as ensuring that you have a pressure drop when the control valve opens. The necessary energy must still be available at the exhaust to pump its way around - that's normally "wasted" - unless you have a turbo. - -- Real Name: Bernd Felsche Email: nospam.bernie@xxx.au http://www.perth.dialix.com.au/~bernie - Private HP - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sun, 12 Mar 100 18:38:09 +0800 (WST) From: Bernd Felsche Subject: Re: Stratified Charge DI with EGR Ade + Lamb Chop writes: >At 19:32 11/03/00 +0800, Bernd Felsche wrote: >>The engine uses quantity-regulation at low load; the torque >>developed depends on the amount of fuel injected. The amount of air >>sucked in and ignition timing have little effect on torque. >I thought you cannot use fuel/ignition to control torque o/p? Don't you end >with exccesivly hot combustion? I can understand using EGR to control the >torque o/p... the oposite of NOS injection :-) Lean-burn with stratified charge "rewrites" some of the old rules. Read the further articles in this thread which explain how the amount of fuel injected is the primary determinant for torque output. - -- Real Name: Bernd Felsche Email: nospam.bernie@xxx.au http://www.perth.dialix.com.au/~bernie - Private HP - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ End of DIY_EFI Digest V5 #100 ***************************** 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".