Dan M Posted March 7, 2009 Posted March 7, 2009 This is what I mean Dan - http://www.dpguzzi.com/efiman.pdf Look at the page 12 of the PDF. True, different part types, but identical NTCs. I see what you are saying G2G. I've been testing these types of sensors for decades and can not remember air & coolant having the same ranges ever before. They do have to both read full cold so perhaps they have the same thermistor only one is in-cased on brass and one is exposed to airflow. One thing that sticks out is on those charts is they do say "theoretical data" - Makes me wonder. I think raz is onto something when he says accurate enough. As I stated in an earlier post, some manufacturers give a 15% variance. Looking back at this lengthly thread, it appears some offer knowledge and hard numbers to substantiate theories, some offer actual experimenting and report results to substantiate theories, some offer hands on experience with these systems to substantiate theories. Others, well some others just offer argument. It is just as easy for you to grab your meter and calculator and do a comparison. What's holding you back? Like you said, 8 year olds can do it.
Dan M Posted March 7, 2009 Posted March 7, 2009 Regarding at what temperature the thermistor is most accurate I'm not sure if you or Dan is [this grammatical incident beats me. You are, he is, you and he are, you or he... are?] Depends on the neighborhood (or 'hood) Raz. Having the chance almost daily to study grammar from the hood, I seem to hear "are" as "is" and "is" as "be" or "go"
Guest ratchethack Posted March 7, 2009 Posted March 7, 2009 Here are the voltages1) and, more importantly, what the ECU reads2). The ADC column is what the AD converter should end up with. It's an integer between 0 (0 volts) and 1023 (5 volts). °C ohms mV ADC -40 100950 4927 1009 -30 53100 4863 996 -20 29120 4755 974 -10 16600 4586 939 0 9750 4333 887 10 5970 3996 818 20 3750 3571 731 25 3000 3333 683 30 2420 3087 632 40 1600 2581 529 50 1080 2093 429 60 750 1667 341 70 525 1296 265 80 380 1011 207 90 275 775 159 100 205 601 123 110 155 468 96 125 100 313 64 1, 2) this is based on the assumptions the ECU use a 1K5 fixed bridge resistor and a 10 bit ADC, like MyECU. I do not know for sure if that is the case. HA!!! WELL DONE RAZ, WELL DONE!!! Finally someone puts a few numbers "on paper" and comes up with a plausible explanation. I am fishing for this kind of argumentation for quite a while now, but it seems that our "scientists" are more inclined to writing essays on philistines, sincerity and seat-o-pants experimenting methods then to pulling out their r(d)usty calculators and doing things that an 8-year old could do. Please tell us, G2G, exactly what the above set of data assumptions explains to you, and since you've been "fishing for this kind of argumentation for quite awhile now", what "argumentation", exactly, would that be? Try as I might, I just don't see any argument -- anywhere in this thread -- with any of the data Raz posted?? I mean, this is all well and good as far as academic information goes, and kudo's to Raz for doing the conversions -- but if this is exactly what you've been looking for as you state above, G2G -- now that you have it, I'd like to know what you intend to do with it?? The assumed (not measured) data he posted is on the input side of the ECU. It tells ZERO about how the ECU modifies the pulsewidth signal feed to the injectors according to temperature. But even if you could somehow come up with the ECU output data with an actual measurement (as opposed to an assumption like the "argumentation" you've been looking for above) -- other than a very nice looking set of data on "on paper", what would you possibly propose to do with THAT?? Everyone, how about some rough models/calculations on influence of air gap, heatsink, resistor, whatnot? The ones that include some numbers rather then descriptions of your seats of pants? Um, if you're so interested in models, calculations, and numbers, G2G, what's wrong with YOUR calculator?? Enquiring minds. . . (well, you know). . . If you have trouble telling us wot this explains to you, why you've been fishing for exactly this, and using your calculator, maybe you could find an 8 year-old Philistine to help you.
Greg Field Posted March 8, 2009 Posted March 8, 2009 The two do not accomplish the same thing.Your method is like taking a square wheel, turning it into an octagon and calling it round Adding thermal transmitting goop speeds up and increases the temperature reading, reducing the over-enrichening at low engine temps. Field loop gromenators controlled by microprocessors if properly applied would result in a much more ideal fuel mixture, much more of the time. Quite right. I should've specified the Philistine brand of rheostatic thrunge gromenators. Thank-you for correcting me.
dlaing Posted March 8, 2009 Posted March 8, 2009 Regarding at what temperature the thermistor is most accurate I'm not sure if you or Dan is [this grammatical incident beats me. You are, he is, you and he are, you or he... are?] wrong, or both. I'm leaning towards you are both right but are looking at in from different views I think it's Accurate Enough [tm] for air and oil temps in a Guzzi pump that is, if it's correctly mounted... Ideally my air temp sensor should be mounted INSIDE the air filter box, not near the triple clamp. And the oil temp sensor should sit in the sump, immersed in oil, or be called something else. Why do you think Dan is correct when he says, "Looking at the spec'd sensor's values. It is ranged to be most sensitive in the 90C to 110C area"? Sensitiveness to me means that the Volts or Ohms will vary more with less change in temperature. According to the chart you presented, the greatest variation in Volts over a ten degree change in temperature occurs between thirty and forty degrees. FWIW the sensor is least sensitive between the -40 and the -30, ( the average temperature in Sweden ) And the next point of equal insensitivity probably occurs beyond the opposite end of the spectrum, in Death Valley when a 140mph blast across the open desert turns into a 20 minute ride behind an RV going 10 MPH up a long twisty road with no chance to safely pass. In that situation, I suspect the temperature may get over 125C, and maybe just a hot Summer day stuck in traffic in Milan could bring the temperature out of the spec'd range. If it does go out of range, might we see the bridging effect and maximum richness???? Maybe that is the vapor lock some people have experienced?!? °C ohms mV ADC Difference to next ten degrees -40 100950 4927 1009 X -30 53100 4863 996 13 -20 29120 4755 974 22 -10 16600 4586 939 35 0 9750 4333 887 52 10 5970 3996 818 69 20 3750 3571 731 87 25 3000 3333 683 48 30 2420 3087 632 51 40 1600 2581 529 103 50 1080 2093 429 100 60 750 1667 341 88 70 525 1296 265 76 80 380 1011 207 58 90 275 775 159 48 100 205 601 123 36 110 155 468 96 27 125 100 313 64 this row is 15° change so, (32*2/3=~21)
dlaing Posted March 8, 2009 Posted March 8, 2009 Quite right. I should've specified the Philistine brand of rheostatic thrunge gromenators. Thank-you for correcting me. Actually it is the brand, "Philistine Slayer" The brand that slays the notions of materialistic ignoramuses, you know the ones that gold plate their temperature sensor adapters
Dan M Posted March 8, 2009 Posted March 8, 2009 Sensitiveness to me means that the Volts or Ohms will vary more with less change in temperature. From what I've read and as others have said, thermistors are most accurate in the middle of their range. The middle corresponds to the curve in the provided graphs. (we've gone over this) It has since been uncovered that most manufacturers are not so concerned with absolute accuracy as a 15% variance has been allowed by the likes of Ford. Other's including Toyota show a more vague chart but still show a variation that is quite wide. The interesting thing it if you look at some of these graphs the range of acceptable ohms is wider at cold temps, narrows in the middle, and widens again at the other end of the temp range. It is the way they operate. It seems injector pulse-width compensation from temp inputs is made in chunks. Probably as large as 10 degrees F in the normal range and wider than that at extremes. It is still by far more accurate over the range of operation than "the choke is closed when cold and opens when hot" The reason I've cited car companies is for several reasons. I have been working on them for decades and it is where I get my experience on these sensors. They have lead the way in electronic fuel injection and motorcycle injection has followed their science. They make this technical information more available than bike companies. If you don't have access to electronic manuals like Mitchell on Demand or Alldata or have technical service bulletins available as I do, go to the library and look for yourself. You may find that how stuff is designed and operates is not the same as what it means to you.
dlaing Posted March 8, 2009 Posted March 8, 2009 From what I've read and as others have said, thermistors are most accurate in the middle of their range. The middle corresponds to the curve in the provided graphs. (we've gone over this) So, I guess we are all in agreement You just had G2G (presumably) and me thrown off a bit with the incorrect 90-100 C comment.
Guzzi2Go Posted March 8, 2009 Posted March 8, 2009 Please tell us, G2G, exactly what the above set of data assumptions explains to you, and since you've been "fishing for this kind of argumentation for quite awhile now", what "argumentation", exactly, would that be? Try as I might, I just don't see any argument -- anywhere in this thread -- with any of the data Raz posted?? This data set overthrows two statements made in this thread: 1) NTC is most sensitive in 90-110°C range, and this is why it is selected for the application. I am still missing definition of "sensitive". Is it dR/dT? Is it dT/dR? Or something else? If it is dR/dT then the NTC is "loosing on sensitivity" with increase of the temperature. What is maybe not so obvious from this calculation is that the sensitivity of the setup (if that is dU/dT) is actually dependent on the value of the preload resistor. I will post a calculation illustrating that in following post. 2) NTC (or better temperature sensing setup including ECU) does not have sufficient resolution to distinguish temperature changes above 90°C. This is the one I made and is so obviously wrong that I am surprised that it took so long for someone to counter it. I kind of hoped Dan would easily cover it, but he chose not to for whatever reason. Pity, since that would put the discussion quickly back on track. You could have also covered it, but I did not hold my breath. In terms of fishing, call it a "bait". Glad that raz took it, as it shows how a sensible discussion could look like. One makes an unsubstantiated claim, and bang, there is a quality argumentation to either corroborate or overthrow if. Of course, there is an alternative involving Philistines, but I just fail to see how they fit in the context. I mean, this is all well and good as far as academic information goes, and kudo's to Raz for doing the conversions -- but if this is exactly what you've been looking for as you state above, G2G -- now that you have it, I'd like to know what you intend to do with it?? What it tells me is that the temp sensing setup resolution at temperatures between 90-110°C is in average 1/36 or ~0.3°C. Sufficient for accurate measurement of temperature even in that area. Goes with countering the statement I made about inability of the setup to measure temperatures above 90°C. See #2 above. The assumed (not measured) data he posted is on the input side of the ECU. It tells ZERO about how the ECU modifies the pulsewidth signal feed to the injectors according to temperature. But even if you could somehow come up with the ECU output data with an actual measurement (as opposed to an assumption like the "argumentation" you've been looking for above) -- other than a very nice looking set of data on "on paper", what would you possibly propose to do with THAT?? First of all, it is not assumed it is specified. This is what a design or a model starts with. Measurement or experiment is 2nd step in the process executed to confirm the validity of design/model. Which brings me to the question: "Where is YOUR model/design for air-gap or heatsink dimensioning which you are trying to prove by experimentation?" Second, what tells me what ECU does with that info is the OilT line. The RELEVANT line. Stock and MyECU lines have been posted here earlier. Stock OilT line tells me that WM adjusts mixture even in high temperature range, which I may choose to compensate for by adding a resistor (of certain value) in series to the sensor. MyECU OilT line tells me that myECU simply ignores what happens above 40°C ("choke open"), so no need to do anything there. Um, if you're so interested in models, calculations, and numbers, G2G, what's wrong with YOUR calculator?? Enquiring minds. . . (well, you know). . . Well, I did that. Twice. I gave you a calculation on resistor in series to sensor, and the one on influence of a heatsink on measuring temperature. Both may be wrong, but you will just not know until you have put the some numbers in YOUR calculator. Only then you can claim that there is something wrong with MY calculator.
Guzzi2Go Posted March 8, 2009 Posted March 8, 2009 Hmmm, I was sure I posted this already, but looks like the post is gone now. Therefore, once again. If it appears twice at the end, I'll try to remove the copy. The post is to show how resolution of the temp sensing setup varies depending on the preload resistor. Resistor values used in this example are 1.5 and 15kohm.
Dan M Posted March 8, 2009 Posted March 8, 2009 This data set overthrows two statements made in this thread:1) NTC is most sensitive in 90-110°C range, and this is why it is selected for the application. I am still missing definition of "sensitive". Is it dR/dT? Is it dT/dR? Or something else? If it is dR/dT then the NTC is "loosing on sensitivity" with increase of the temperature. What is maybe not so obvious from this calculation is that the sensitivity of the setup (if that is dU/dT) is actually dependent on the value of the preload resistor. I will post a calculation illustrating that in following post. 2) NTC (or better temperature sensing setup including ECU) does not have sufficient resolution to distinguish temperature changes above 90°C. This is the one I made and is so obviously wrong that I am surprised that it took so long for someone to counter it. I kind of hoped Dan would easily cover it, but he chose not to for whatever reason. Pity, since that would put the discussion quickly back on track. You could have also covered it, but I did not hold my breath. In terms of fishing, call it a "bait". Glad that raz took it, as it shows how a sensible discussion could look like. One makes an unsubstantiated claim, and bang, there is a quality argumentation to either corroborate or overthrow if. Of course, there is an alternative involving Philistines, but I just fail to see how they fit in the context. What it tells me is that the temp sensing setup resolution at temperatures between 90-110°C is in average 1/36 or ~0.3°C. Sufficient for accurate measurement of temperature even in that area. Goes with countering the statement I made about inability of the setup to measure temperatures above 90°C. See #2 above. Second, what tells me what ECU does with that info is the OilT line. The RELEVANT line. Stock and MyECU lines have been posted here earlier. Stock OilT line tells me that WM adjusts mixture even in high temperature range, which I may choose to compensate for by adding a resistor (of certain value) in series to the sensor. MyECU OilT line tells me that myECU simply ignores what happens above 40°C ("choke open"), so no need to do anything there. First off, I've read enough forum technical threads to almost automatically lose interest and pass over someone's post when erroneous or unrelated info is posted as fact. Now that you admit to purposely posting it as "bait" There is even more reason to ignore your posts as argumentative. They obviously can not be trusted and offer no constructive or accurate information. Or, this is merely your story now. As I stated recently, many here try to put their heads together to solve problems, let others know how things work and offer possible solutions for known problems. Sometimes we discuss, sometimes we disagree, that is what a forum is for. Arguing for the sake of argument, baiting people and offering known false information has no place in a technical forum. Getting back to the 90-110C range. You are assuming (wrongly) that this is the high end of the thermistors range. It is merely the high end if what the ecu monitors. As stated much earlier, there is little reason to publish numbers for or have any temp compensation way beyond engine overheat. That doesn't mean the thermistor stops changing.
Guzzi2Go Posted March 8, 2009 Posted March 8, 2009 First off, I've read enough forum technical threads to almost automatically lose interest and pass over someone's post when erroneous or unrelated info is posted as fact. Now that you admit to purposely posting it as "bait" There is even more reason to ignore your posts as argumentative. They obviously can not be trusted and offer no constructive or accurate information. Or, this is merely your story now. As I stated recently, many here try to put their heads together to solve problems, let others know how things work and offer possible solutions for known problems. Sometimes we discuss, sometimes we disagree, that is what a forum is for. Arguing for the sake of argument, baiting people and offering known false information has no place in a technical forum. Getting back to the 90-110C range. You are assuming (wrongly) that this is the high end of the thermistors range. It is merely the high end if what the ecu monitors. As stated much earlier, there is little reason to publish numbers for or have any temp compensation way beyond engine overheat. That doesn't mean the thermistor stops changing. Well, EVERYONE is posting their information (I am deliberately not saying argumentation) as a fact. How do you know who to trust? Going by their name? Length of their posts? Some people will not trust anything, some will trust everything. And then, there are those who will ask that claims are backed with some arguments. How good these arguments are, and what can you do with them (in terms of trust) is really up to you. I dare to say here that I am amongst a very few that offered any kind of argumentation around their claims. How good it is, is really up for you to judge, but I am still offering you that choice unlike some others who tend to call one a "Philistine" (would that be an insult? ) for the sake of argumentation. However, if that is your preference, I understand. Coming back to the topic, I am not assuming anything about thermistor's range, and I can't see where did you read that. I KNOW that thermistor's characteristic is a logarithmic function and that it will eventually tail off so the increase of resistance will be negligible beyond certain point. I also KNOW that a semiconductor it is made off will decompose not far beyond 200°C, which limits their applicability to measuring fairly low temperatures (like engine temps). However, for the sake of this argument, let us keep it between 0-120°C. It is quite sufficient for what we have in front of ourselves.
Guest ratchethack Posted March 8, 2009 Posted March 8, 2009 . . .it seems that our "scientists" are more inclined to writing essays on philistines. . . . . .[sigh]. . . The classic lessons of antiquity repeat themselves here, as you've so aptly reminded us by resurrecting the metaphor again, G2G. . . .The Philistine trots out a great walloping arsenal of technologically advanced iron and steel weapons of war of no possible use to him on the field (which easily trump the bronze technology of his adversary). True to his culture, he suffers the self-limiting deficiency of lack of wisdom, and therefore he also suffers the far more significant (and fatal) incompetence of inferior strategy and tactics. The wiser and more experienced adversary again finds the best strategy is to turn the technology of the Philistine to his own advantage, exploiting his lack of wisdom by simply electing not to engage. He stands at relative ease whilst the Philistine runs madly in circles, flailing his weapons about wildly, tiring himself into fatigue, eventually tripping on his steel sword, and severing his own head. . . The adversary collects his nice new weapons whilst the next Philistine wonders how it happened, and prepares to repeat his predecessor's performance. . . . . . So has it ever been (metaphorically speaking), and so shall it ever be. . .
Dan M Posted March 8, 2009 Posted March 8, 2009 Well, EVERYONE is posting their information (I am deliberately not saying argumentation) as a fact. How do you know who to trust? Going by their name? Length of their posts? Some people will not trust anything, some will trust everything. And then, there are those who will ask that claims are backed with some arguments. How good these arguments are, and what can you do with them (in terms of trust) is really up to you. I dare to say here that I am amongst a very few that offered any kind of argumentation around their claims. How good it is, is really up for you to judge, but I am still offering you that choice unlike some others who tend to call one a "Philistine" (would that be an insult? ) for the sake of argumentation. However, if that is your preference, I understand. Coming back to the topic, I am not assuming anything about thermistor's range, and I can't see where did you read that. I KNOW that thermistor's characteristic is a logarithmic function and that it will eventually tail off so the increase of resistance will be negligible beyond certain point. I also KNOW that a semiconductor it is made off will decompose not far beyond 200°C, which limits their applicability to measuring fairly low temperatures (like engine temps). However, for the sake of this argument, let us keep it between 0-120°C. It is quite sufficient for what we have in front of ourselves. No, you are again wrong. When individuals of integrity offer information it is hoped that it will be trusted. There is no attempt to mislead, only to share information. Many including myself have called what we offer theories. We've shared our experiences. Some report their own findings footnoted with YMMV. Some offer solid info on related topics with the mention of assumptions and calculations. You, by your own admission put out wrong information in order to bait others. There is quite a difference. Why anyone would ever again take your information at face value knowing this is beyond me. There are people on this forum that have far more knowledge of and experience with Moto Guzzis than myself. (Pete Roper is one to name a name) I generally take their advice and regard the information they post as accurate and trusted. So I believe the question is who to trust, not what. What I read was a inference that 90-110 was not in the middle of the range.
Dan M Posted March 8, 2009 Posted March 8, 2009 So, I guess we are all in agreement You just had G2G (presumably) and me thrown off a bit with the incorrect 90-100 C comment. What was incorrect? If the thermistor doesn't go open until below -40C and doesn't short until beyond 180C, is 90 not mid range? Are you just splitting hairs? You'll have to trust me on this or perhaps get a hold of someone with a scanner hook it up to a vehicle and disconnect a TPS. Check temp with it open and jump the wires and check temp shorted. You'll see that unless the computer defaults to a mid value when it sees a signal out of range, you'll see (in Fahrenheit) at least -40F open and as much as 360F shorted. This is what the computer reports on the scanner. Some manufacturers show different limits so YMMV and all of that.
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