If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#31
|
|||
|
|||
William R. Watt wrote:
> Ray ) writes: > > >>And the reason the throttle doesn't open? Throttle return springs want >>to pull it shut. Your foot holds it open. > > > safety feature. dead man's throttle. > > -- > ------------------------------------------------------------------------------ > William R Watt National Capital FreeNet Ottawa's free community network > homepage: www.ncf.ca/~ag384/top.htm > warning: non-FreeNet email must have "notspam" in subject or it's returned and your point is? he was wondering why the air flowing through the carb doesn't force the throttle open... |
Ads |
#32
|
|||
|
|||
"Lawrence Glickman" > wrote in message ... > On Mon, 03 Jan 2005 07:22:39 GMT, Ray > wrote: > > >Lawrence Glickman wrote: > >> > >>>It "sucks" as much air/fuel out of the intake (and past the mostly > >>>closed throttle) as it can. You now have 14psi outside the intake and 4 > >>>psi in the intake, which works out to -10 psi in comparison - aka a > >>>vacuum. (think of a vacuum gauge showing 10psi at idle - that's how > >>>hard the piston is "sucking" at the throttle blade wanting more...) > >> > >> > >> for some reason, right at this point, I don't know why throttle plate > >> doesn't open wide to decrease vacuum. You are making the engine do > >> EXTRA WORK by forcing it to pull a vacuum, don't you know that? > >> > >> There is no difference whether you are forcing an engine to create > >> pressure ( downstroke on fuel ignition ) or downstroke on vacuum. > >> You're nulling-out fuel efficiency by forcing the pistons on the > >> intake stroke to work against a vacuum. I'll sign my name to that, > >> but don't try to cash it until next year sometime. > >> > > > >Which is why some of the new BMW's have done away with the throttle as > >we know it. Think adjustable valvetrain. And that's why your standard > >car engine is most efficient around 80% load - the throttle kills > >efficeincy, even if I can't spell it. > > > >http://www.bmwworld.com/technology/valvetronic.htm > > > >And the reason the throttle doesn't open? Throttle return springs want > >to pull it shut. Your foot holds it open. > > > >Ray > > There Ray, is the reason the USA auto industry has gone into the > s*tter. > > Those Bavarians! Leave it to them. Or the Japanese. I used to work > for both of them. Not on -cars- but on other of their inventions. > They are _innovative_, always pushing the envelope. > > This new technology doesn't look like it is expensive to implement, > what is going to screw the US balls to the wall is that the Bavarians > have the PATENT! > You don't want to. One thing missing in the discussion here is what happens to the fuel/air mixture in the presense of vacuum. Keep in mind that a high vacuum drops the boiling point of gasoline. So, when the engine is crusing along at 50Mph or so, and you have about a 16Hg vacuum in the intake manifold, when the atomized fuel from the varb venturi or TBI or intake injectors hits that vacuum it instantly converts basically into a gas, ie: vaporized fuel, not just atomized. Then in the transition through the valves the gas is stirred around even more in the cylinder. gasoline vapor burns with a lot more energy and a lot faster and more power than atomized gasoline of the same volume. Thus your fuel efficiency at part throttle is much higher than it is at wide open throttle, where the fuel air mix that enters the cylinders is more atomized fuel droplets, due to a better burn. That incidentally is one of the tradeoffs in normally aspirated engines, to develop full power means you have to have as much air as possible coming into the cylinder, but at WOT when this happens, the fuel mixture isn't optimal - thus you have to richen it up to compensate and your economy drops. This also is one reason oxygen overloading (ie Nitrous Oxide) works so well in drag cars and such, the additional oxygen introduced displaces some of the inert nitrogen, and the burn is vastly improved, as each gasoline droplet has a much higher concentration of oxygen atoms and therefore much higher chance of complete combustion. Ted |
#33
|
|||
|
|||
Ted Mittelstaedt wrote:
> "Lawrence Glickman" > wrote in message > ... > >>On Mon, 03 Jan 2005 07:22:39 GMT, Ray > wrote: >> >> >>>Lawrence Glickman wrote: >>> >>>>>It "sucks" as much air/fuel out of the intake (and past the mostly >>>>>closed throttle) as it can. You now have 14psi outside the intake and > > 4 > >>>>>psi in the intake, which works out to -10 psi in comparison - aka a >>>>>vacuum. (think of a vacuum gauge showing 10psi at idle - that's how >>>>>hard the piston is "sucking" at the throttle blade wanting more...) >>>> >>>> >>>>for some reason, right at this point, I don't know why throttle plate >>>>doesn't open wide to decrease vacuum. You are making the engine do >>>>EXTRA WORK by forcing it to pull a vacuum, don't you know that? >>>> >>>>There is no difference whether you are forcing an engine to create >>>>pressure ( downstroke on fuel ignition ) or downstroke on vacuum. >>>>You're nulling-out fuel efficiency by forcing the pistons on the >>>>intake stroke to work against a vacuum. I'll sign my name to that, >>>>but don't try to cash it until next year sometime. >>>> >>> >>>Which is why some of the new BMW's have done away with the throttle as >>>we know it. Think adjustable valvetrain. And that's why your standard >>>car engine is most efficient around 80% load - the throttle kills >>>efficeincy, even if I can't spell it. >>> >>>http://www.bmwworld.com/technology/valvetronic.htm >>> >>>And the reason the throttle doesn't open? Throttle return springs want >>>to pull it shut. Your foot holds it open. >>> >>>Ray >> >>There Ray, is the reason the USA auto industry has gone into the >>s*tter. >> >>Those Bavarians! Leave it to them. Or the Japanese. I used to work >>for both of them. Not on -cars- but on other of their inventions. >>They are _innovative_, always pushing the envelope. >> >>This new technology doesn't look like it is expensive to implement, >>what is going to screw the US balls to the wall is that the Bavarians >>have the PATENT! >> > > > You don't want to. One thing missing in the discussion here is what > happens to the fuel/air mixture in the presense of vacuum. > > Keep in mind that a high vacuum drops the boiling point of > gasoline. So, when the engine is crusing along at 50Mph or so, > and you have about a 16Hg vacuum in the intake manifold, > when the atomized fuel from the varb venturi or TBI or > intake injectors hits that vacuum it instantly converts basically > into a gas, ie: vaporized fuel, not just atomized. Then in the > transition through the valves the gas is stirred around even > more in the cylinder. gasoline vapor burns with a lot more > energy and a lot faster and more power than atomized gasoline > of the same volume. Thus your fuel efficiency at part throttle is > much higher than it is at wide open throttle, where the fuel air mix that > enters > the cylinders is more atomized fuel droplets, due to a better > burn. > > That incidentally is one of the tradeoffs in normally aspirated engines, > to develop full power means you have to have as much air as > possible coming into the cylinder, but at WOT when this happens, > the fuel mixture isn't optimal - thus you have to richen it up to > compensate and your economy drops. > > This also is one reason oxygen overloading (ie Nitrous Oxide) works > so well in drag cars and such, the additional oxygen introduced > displaces some of the inert nitrogen, and the burn is vastly improved, > as each gasoline droplet has a much higher concentration of oxygen atoms > and therefore much higher chance of complete combustion. > > Ted > > when i was doing research on alternative fuels and alternative combustion types, two other technologies impressed me. toyota is working on a direct injection engine which they claim would enable them to hit 50:1 A/F ratio. another was a kind of rotary engine which had no crankshaft as we know it, and no throttle body. rather, the engine speed is controlled by fuel delivery. interesting ideas if they ever get off the ground, or some oil company doesn't stick the patent under it's ass. OT: and something very cool: i was rummaging through a friend's house, and i found a june (or july) 1968 popular science magazine. it had some great stuff in it. my favorite was the explanation of Ford's new fuel injection and ignition system. reminds me of a diesel setup, running about 400psi and direct injection to boot! was interesting to read on this "primitive" system. -- Ben Jerew ASE Master Technician New Country Lexus of Latham, NY Amateur Off-Roader |
#34
|
|||
|
|||
Ray wrote: > and your point is? > he was wondering why the air flowing through the carb doesn't force the > throttle open... It does. The return springs are by design stronger than the force the airflow exerts on the throttle blades even at high vacuum. Try it with the return springs disconnected if you want a demonstration, just keep your hand on the key so you can kill the engine before the engine overspeeds (BTDT, not intentionally) This may not work on all carburetors or throttle bodies as some may have a small built in return spring to prevent just such a thing from happening if the primary return spring breaks. Incidentally, I believe for many racing classes a minimum of two return springs are required to prevent runaway if one breaks. nate |
#35
|
|||
|
|||
On Tue, 4 Jan 2005 01:28:32 -0800, "Ted Mittelstaedt"
> wrote: > >"Lawrence Glickman" > wrote in message .. . >> On Mon, 03 Jan 2005 07:22:39 GMT, Ray > wrote: >> >> >Lawrence Glickman wrote: >> >> >> >>>It "sucks" as much air/fuel out of the intake (and past the mostly >> >>>closed throttle) as it can. You now have 14psi outside the intake and >4 >> >>>psi in the intake, which works out to -10 psi in comparison - aka a >> >>>vacuum. (think of a vacuum gauge showing 10psi at idle - that's how >> >>>hard the piston is "sucking" at the throttle blade wanting more...) >> >> >> >> >> >> for some reason, right at this point, I don't know why throttle plate >> >> doesn't open wide to decrease vacuum. You are making the engine do >> >> EXTRA WORK by forcing it to pull a vacuum, don't you know that? >> >> >> >> There is no difference whether you are forcing an engine to create >> >> pressure ( downstroke on fuel ignition ) or downstroke on vacuum. >> >> You're nulling-out fuel efficiency by forcing the pistons on the >> >> intake stroke to work against a vacuum. I'll sign my name to that, >> >> but don't try to cash it until next year sometime. >> >> >> > >> >Which is why some of the new BMW's have done away with the throttle as >> >we know it. Think adjustable valvetrain. And that's why your standard >> >car engine is most efficient around 80% load - the throttle kills >> >efficeincy, even if I can't spell it. >> > >> >http://www.bmwworld.com/technology/valvetronic.htm >> > >> >And the reason the throttle doesn't open? Throttle return springs want >> >to pull it shut. Your foot holds it open. >> > >> >Ray >> >> There Ray, is the reason the USA auto industry has gone into the >> s*tter. >> >> Those Bavarians! Leave it to them. Or the Japanese. I used to work >> for both of them. Not on -cars- but on other of their inventions. >> They are _innovative_, always pushing the envelope. >> >> This new technology doesn't look like it is expensive to implement, >> what is going to screw the US balls to the wall is that the Bavarians >> have the PATENT! >> > >You don't want to. One thing missing in the discussion here is what >happens to the fuel/air mixture in the presense of vacuum. > >Keep in mind that a high vacuum drops the boiling point of >gasoline. So, when the engine is crusing along at 50Mph or so, >and you have about a 16Hg vacuum in the intake manifold, Which, you may be interested to know, Ted, I am measuring right at this moment. My Series A measurements set baseline parameters for 1) vehicle speed (mph) 2) throttle position (%) 3) HO2S B1 S1 (V) 4) HO2S B2 S1 (V) 5) battery voltage (V) My Series B measurements are being recorded right now, so I don't know what I am going to see yet. But they are set up right now for 1) vehicle speed (mph) -this is not adjustable- 2) Intake Manifold Pressure 3) air flow rate 4) fuel pressure 5) fuel system status So this is going to take a few days to compile the data, then I will download it to my computer and look at the numbers and graphs. It is a work in progress. I'll give it 3 or 4 days to log data, or maybe longer as I would like to take the car out on the Interstate and run it at 60 mph, and then I will pull the chip and see what I get. Until then, I am in a *partial* vacuum knowledge wise ( yah, I know ! >when the atomized fuel from the varb venturi or TBI or >intake injectors hits that vacuum it instantly converts basically >into a gas, ie: vaporized fuel, not just atomized. Well that's nice ( not! ) because once it is inside the cylinders, it is going to take some of the stroke to get it back to 1 atmosphere. Wasted displacement. > Then in the >transition through the valves the gas is stirred around even >more in the cylinder. gasoline vapor burns with a lot more >energy and a lot faster and more power than atomized gasoline >of the same volume. Thus your fuel efficiency at part throttle is >much higher than it is at wide open throttle, where the fuel air mix that >enters >the cylinders is more atomized fuel droplets, due to a better >burn. When the pistons compress this *vapor* back to 1 atmosphere, the so-called advantages of pumping fuel into a partial vacuum are "out the window" And it gets even worse from there. It is going up to 9.7 atmospheres or MORE before the downstroke even _begins_. >That incidentally is one of the tradeoffs in normally aspirated engines, >to develop full power means you have to have as much air as >possible coming into the cylinder, but at WOT when this happens, >the fuel mixture isn't optimal - thus you have to richen it up to >compensate and your economy drops. > >This also is one reason oxygen overloading (ie Nitrous Oxide) works >so well in drag cars and such, the additional oxygen introduced >displaces some of the inert nitrogen, and the burn is vastly improved, >as each gasoline droplet has a much higher concentration of oxygen atoms >and therefore much higher chance of complete combustion. > >Ted Well, give me enough time ( a few days ) to log some data. I'll get back to ya. Lg |
#36
|
|||
|
|||
On Tue, 4 Jan 2005 01:28:32 -0800, "Ted Mittelstaedt"
> wrote: > >"Lawrence Glickman" > wrote in message .. . >> On Mon, 03 Jan 2005 07:22:39 GMT, Ray > wrote: >> >> >Lawrence Glickman wrote: >> >> >> >>>It "sucks" as much air/fuel out of the intake (and past the mostly >> >>>closed throttle) as it can. You now have 14psi outside the intake and >4 >> >>>psi in the intake, which works out to -10 psi in comparison - aka a >> >>>vacuum. (think of a vacuum gauge showing 10psi at idle - that's how >> >>>hard the piston is "sucking" at the throttle blade wanting more...) >> >> >> >> >> >> for some reason, right at this point, I don't know why throttle plate >> >> doesn't open wide to decrease vacuum. You are making the engine do >> >> EXTRA WORK by forcing it to pull a vacuum, don't you know that? >> >> >> >> There is no difference whether you are forcing an engine to create >> >> pressure ( downstroke on fuel ignition ) or downstroke on vacuum. >> >> You're nulling-out fuel efficiency by forcing the pistons on the >> >> intake stroke to work against a vacuum. I'll sign my name to that, >> >> but don't try to cash it until next year sometime. >> >> >> > >> >Which is why some of the new BMW's have done away with the throttle as >> >we know it. Think adjustable valvetrain. And that's why your standard >> >car engine is most efficient around 80% load - the throttle kills >> >efficeincy, even if I can't spell it. >> > >> >http://www.bmwworld.com/technology/valvetronic.htm >> > >> >And the reason the throttle doesn't open? Throttle return springs want >> >to pull it shut. Your foot holds it open. >> > >> >Ray >> >> There Ray, is the reason the USA auto industry has gone into the >> s*tter. >> >> Those Bavarians! Leave it to them. Or the Japanese. I used to work >> for both of them. Not on -cars- but on other of their inventions. >> They are _innovative_, always pushing the envelope. >> >> This new technology doesn't look like it is expensive to implement, >> what is going to screw the US balls to the wall is that the Bavarians >> have the PATENT! >> > >You don't want to. One thing missing in the discussion here is what >happens to the fuel/air mixture in the presense of vacuum. > >Keep in mind that a high vacuum drops the boiling point of >gasoline. So, when the engine is crusing along at 50Mph or so, >and you have about a 16Hg vacuum in the intake manifold, Which, you may be interested to know, Ted, I am measuring right at this moment. My Series A measurements set baseline parameters for 1) vehicle speed (mph) 2) throttle position (%) 3) HO2S B1 S1 (V) 4) HO2S B2 S1 (V) 5) battery voltage (V) My Series B measurements are being recorded right now, so I don't know what I am going to see yet. But they are set up right now for 1) vehicle speed (mph) -this is not adjustable- 2) Intake Manifold Pressure 3) air flow rate 4) fuel pressure 5) fuel system status So this is going to take a few days to compile the data, then I will download it to my computer and look at the numbers and graphs. It is a work in progress. I'll give it 3 or 4 days to log data, or maybe longer as I would like to take the car out on the Interstate and run it at 60 mph, and then I will pull the chip and see what I get. Until then, I am in a *partial* vacuum knowledge wise ( yah, I know ! >when the atomized fuel from the varb venturi or TBI or >intake injectors hits that vacuum it instantly converts basically >into a gas, ie: vaporized fuel, not just atomized. Well that's nice ( not! ) because once it is inside the cylinders, it is going to take some of the stroke to get it back to 1 atmosphere. Wasted displacement. > Then in the >transition through the valves the gas is stirred around even >more in the cylinder. gasoline vapor burns with a lot more >energy and a lot faster and more power than atomized gasoline >of the same volume. Thus your fuel efficiency at part throttle is >much higher than it is at wide open throttle, where the fuel air mix that >enters >the cylinders is more atomized fuel droplets, due to a better >burn. When the pistons compress this *vapor* back to 1 atmosphere, the so-called advantages of pumping fuel into a partial vacuum are "out the window" And it gets even worse from there. It is going up to 9.7 atmospheres or MORE before the downstroke even _begins_. >That incidentally is one of the tradeoffs in normally aspirated engines, >to develop full power means you have to have as much air as >possible coming into the cylinder, but at WOT when this happens, >the fuel mixture isn't optimal - thus you have to richen it up to >compensate and your economy drops. > >This also is one reason oxygen overloading (ie Nitrous Oxide) works >so well in drag cars and such, the additional oxygen introduced >displaces some of the inert nitrogen, and the burn is vastly improved, >as each gasoline droplet has a much higher concentration of oxygen atoms >and therefore much higher chance of complete combustion. > >Ted Well, give me enough time ( a few days ) to log some data. I'll get back to ya. ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// BULLY BULLY I say there Old Chap, this is a kick in the knickers......... My Series B "Intake air manifold" pressure turns out to be "not supported by vehicle" Bully Bully I've moved on to Series C now P1) vehicle speed (mph) P2) HO2S B1 S2 (V) P3) HO2S B2 S2 (V) P4) coolant temperature P5) timing advance and, that will be it. My baseline parameters for THIS car at THIS mileage at THIS time. Now, I know what the tolerances -are-, e.g. fuel system pressure between 35 and 45 psi, so I can see that it is 40 psi +/- within tolerance, and so on and so forth. After Series C is finished, I'll go back to just logging whatever. Probably some eclectic mix of the above. But at the very minimum I've compiled a library of what my engine should look like, and if something goes south on me, I can refer to these charts for an *idea* Along with my OBDII Scan tool I should be able to narrow things down. Bully. Lg |
#37
|
|||
|
|||
N8N wrote:
> Ray wrote: > > >>and your point is? >>he was wondering why the air flowing through the carb doesn't force > > the > >>throttle open... > > > It does. The return springs are by design stronger than the force the > airflow exerts on the throttle blades even at high vacuum. Try it with > the return springs disconnected if you want a demonstration, just keep > your hand on the key so you can kill the engine before the engine > overspeeds (BTDT, not intentionally) > > This may not work on all carburetors or throttle bodies as some may > have a small built in return spring to prevent just such a thing from > happening if the primary return spring breaks. Incidentally, I believe > for many racing classes a minimum of two return springs are required to > prevent runaway if one breaks. > > nate > Or what is normally done is to slightly offset the throttle shaft so that the pressure forces will always tend to close the throttle. |
#38
|
|||
|
|||
dyno wrote:
> N8N wrote: > >> Ray wrote: >> >> >>> and your point is? >>> he was wondering why the air flowing through the carb doesn't force >> >> >> the >> >>> throttle open... >> >> >> >> It does. The return springs are by design stronger than the force the >> airflow exerts on the throttle blades even at high vacuum. Try it with >> the return springs disconnected if you want a demonstration, just keep >> your hand on the key so you can kill the engine before the engine >> overspeeds (BTDT, not intentionally) >> >> This may not work on all carburetors or throttle bodies as some may >> have a small built in return spring to prevent just such a thing from >> happening if the primary return spring breaks. Incidentally, I believe >> for many racing classes a minimum of two return springs are required to >> prevent runaway if one breaks. >> >> nate >> > Or what is normally done is to slightly offset the throttle shaft so > that the pressure forces will always tend to close the throttle. That works up to a point, but you'll still get a little surprise once they go "over center" (or so I've heard...) nate -- replace "fly" with "com" to reply. http://home.comcast.net/~njnagel |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
1996 Dodge Grand Caravan LE AC/Heater Blower, Relay and Resistor Block Problems 101 | HeadlessHorseman | Dodge | 0 | January 5th 05 02:49 PM |
Climatronic Diagnostic Controls | Luís Lourenço | Audi | 1 | November 12th 04 08:22 AM |
window lift motor | Zaphod | Saturn | 4 | June 2nd 04 11:35 AM |