Waiting on some oil analysis kits to proceed.
This is an interesting patent about inffering oil temperature from Ford.
US20190101458A1.pdf
Phaser operation Ford patent.jpg
Waiting on some oil analysis kits to proceed.
This is an interesting patent about inffering oil temperature from Ford.
US20190101458A1.pdf
Phaser operation Ford patent.jpg
I'm really interested to see the oil analysis results.
The Fig 2 diagram in the pdf shows well how the solenoid works, except they neglect to show the center valve being narrower than the oil supply slot and also the 3 open leakage paths between the valve and the cavities in the actuator. I can post pics of an actual gen3 spool valve internals if anyone cares.
I'm still a little confused on why we can't differentiate between slight discrepancies in commanded vs actual and massive discrepancies in the 10-40 degree range.
I'm not convinced that because a patent fails to address something, it's evidence that it doesn't exist. I'm also not convinced that engineers are required to build things exactly the way a patent suggests.
If the mechanical timing hasn't slipped, if the duty cycle is 0%, and if the exhaust cam is 10-40 degrees off, what is the explanation?
I can post pics of an actual gen3 spool valve internals if anyone cares.
I'd like to see these pics
IMG_5509.jpgOriginally Posted by K44
The spool is above the housing. 0 duty cycle is advance, spool all the way up due to the spring. 100% duty cycle is retard, spool all the way down. Oil enters from the pump into the center slot in the housing. At 0% duty cycle and spool all the way up, oil exits the top slot in the housing and travels through the camshaft journal to the advancing cavities in the actuator. When the spool is up, it also opens up the bottom slot to the exit hole on the bottom end (not shown), thereby draining the retard cavity in the actuator. At 100% duty cycle, the opposite happens. In the null state (neither advance nor retard from current position), the spool directs oil equally to both feeds to the actuator because the journal still needs lubricating oil.
When I put together the things I've learned, that a) the issue is strongly correlated to oil viscosity and b) the control oil travels through the cam bearing journal to reach the phaser actuator, it really limits the possible causes. Obviously, the drag placed on the actuator is more than the actuator torque can overcome. The oil pressure acting in the actuator combined with the spiral "torsional assist" spring *should* be enough to overcome the torque, but it isn't and it's not just an isolated case. The only thing I can come up with is that control oil is leaking from the "advance" passage in the journal to both the "retard" passage and the crankcase through the journal clearance. The journal clearance can be up to .003" stock, which is quite large for a 1.3" journal. This leakage would reduce the oil pressure acting within the phaser actuator. Higher viscosity would reduce the leakage in the journal and more pressure would result in the phaser actuator cavities. Either that or one of the actuator tip seals has failed (in my case).
I brought up slight discrepancies in commanded vs actual as we were discussing the mapped points weight. I just wanted to say the snap points and lines account for this, so its not dsitributing weight over a bunch of the points all the time. I didn't want to discuss 10-40* off commanded situations, but situations where you are in control.
Using what you said as an example, I then needed to correct other people who were saying the phasers have an engine horsepower or torque rating, and that I just don't know what that is because I haven't found it. It completely went against my understanding of the phasers. The chain tensioners role in cam positions are a completely different topic. I didnt want to respond directly to the other person as they will probably try to have me kicked of the forum again. At this point I don't even care tho.
Im not disagreeing that you and Mike... others, are seeing huge swings off commanded. Your phasers are not working properly. Aeration, oil being trapped, some other physical limitation issue, All the vanes would need to be leaking like crazy, or just not have good oil supply to begin with to completely lose control. .... IDK. Its not normal operation of properly functioning phasers. New people with little experience, need to know what to expect and what isn't normal, which is why I am going to the trouble of logging and tring to show what normal is. With the way this is being treated, these new people might think its very difficult to impossible to have precision cam angle control.
The whole reason for the patent is I was tring to understand how oil temp is inffered, because I can't log it, and I will often come up with math to keep track of things I can't log directly. Turns out its very dependant on the oil viscosity the calibration was built around, properly working cam phasers, and the concept of a null duty cycle which achieves a position of the spool valve that creates a stationary phaser. It had a great explaination about how the phasers are suppose to work, very similar to how I was attempting to explain it and show.
Drain/ leak, are not good words to describe it (even the patent uses them). The oil exiting the cavitys remains under presssure, the spool valve just allows it some where to go. Its pushed out of the cavity by the vane, which is being pushed by the oil pressure entering the cavity on the other side of it.
I understand now, thank you.
Assuming an oil temp inference model, here's how it works in my world, I'll assume that it's at least remotely similar for Coyote:
An initial oil temp value is pulled from a 3d table, X axis RPM and Y axis load. Then there are two adjustment factors, one for ECT and one for Ambient Temperature. In many of the strategies these are set to zero, which creates a multiply by zero/no correction for temperature conditions (which I find odd, but it is what it is).
The adjustment factor is added onto the 3D table value like this: Table lookup += ((ECT_factor * (Current ECT - 200) + (Ambient_factor * (Current ambient - 100)).
There are clips and filters applied as well to smooth this logic out, but with the 3D table values and the two temperature values, you could probably make a spreadsheet to get your input value for VCT calculations.
I just changed from Mobil1 5W50 (data snips above) to Redline 5W50, which has a higher "warm" viscosity spec (21.0 cst vs 17.1). For a like-for-like comparison, the following is the 3rd pull in 1.5 minutes to compare to above:
3rd pull redline.JPG
You can see that the fresh Redline with higher viscosity controls significantly better than even the fresh Mobil1 of lower viscosity, even within the same SAE grade.
I went on to *try* to force an error by making 5 pulls within 2 minutes to get the oil as hot as I could. The 5th pull is next:
5th pull redline.JPG
This is notably worse than the 3rd pull, but I would say it is still within control (though with more error) because the solenoid is yet to be forced to 0 duty cycle.
This, I believe, further reinforces the earlier assertation that higher viscosity improves the 10-40 deg error we are seeing when more drag load is added to the phaser.
Last edited by engineermike; 05-04-2023 at 07:44 AM.
Hot 40-60 0W-16.jpg
6:57pm
2nd gear pull 40-60 with fresh Mobile 1 0w-16 after 28 minutes of driving and 5 previous pulls. 1-2.5* of cam error.
Hot 60-130 0W-16.jpg
6:59pm
6th gear pull 60-130 just after that 2nd gear pull. less than 1* of cam error.
Hot 60-130 0W-16 #2.jpg
7:03pm
another 6th gear pull right after that. same if not less error than the pull before.
Test sample kit is in the mail. Maybe ill have test results before next weekend. Oil was black and about 1 quart low.
I can not replicate hot oil temp loss of control you are seeing. (subjective as we can't log what it is.)
2nd gear fast RPM acceleration still produces more error than 6th gear slow RPM acceleration.
no significant difference seen between used/ low 5w-20 motorcraft and fresh/ properly filled 0w-16 mobile 1.
Next oil change I might do much sooner than normal, and I'll try 5w-50 or something much thicker than 0w-16 or 5w-20.
I also wanted to point out that duty cycles for null position, and therefore all advance and retard rates, trend higher as the oil warms up and gets thinner for both the exhaust and intake, just as indicated by their feed forward models.
DC trend.jpg
Last edited by murfie; 05-07-2023 at 03:15 AM.
Thanks, Murfie. I really don't think oil viscosity is going to affect yours significantly because they are "within control". In other words, the error recorded is what the logic is allowing it to be intentionally. If it were shooting for less error, it has the span of control to bring it down. I think the viscosity just affects what the null DC is. Speaking of which, why do you suppose your null duty cycle drifts as the oil heats up, but at WOT they are all basically the same hot or cold?
The Motorcraft 5W20 warm viscosity is 8.7 cst new and probably lower used. The Mobil1 0W16 is 7.6 new, which technically falls into the range for 20 as well so it could be dual graded. These lighter weight oils are all so close together it's like splitting hairs.
The Patent I post describes the oil temperature and the solenoid voltage/ resistance having a relationship. Which makes sense in how it increases DC for both exhaust and intake, when increase in DC does the opposite for which direction their phase rates go.
WOT pulls and this temperature relationship is not giving plausible results. The only way its plausible is accounting for friction increases with RPMs, but also increases with decreasing temperature. the friction models are not used at operating temperatures, so I don't think inffered oil temp gets updated at WOT or at least not by anything the cams/ phasers are doing.
It also doesn't mention anything about compensating for oil weight or viscocity changes. So im going through collecting data using the extremes of the oil weights that I can get my hands on to see if there is any effect on control. It might just be an effect on the extremes at the maximum phase rates, it might have no effect at all. If you say its helping you, I should see something change about the control.
Hey so I know you guys are having a really in-depth discussion about the mechanical limits of the VVT system...
But I wanted to ask, the MP's for the torque calculation, are they not used during OP mode? I'm basing this entirely off the HPTuners description that is in VCM scanner when you hover over them.
torque MPs.png
So these torque MP's are only used for part throttle and to maintain drivability? If they are only used at stoich, then they by definition wont be used in OP mode because we are not at stoich.
I have absolutely no idea what I'm doing
The OP Mapped Point Torque values are used if OP is active AND the OP Mapped Point is enabled. In the Gen3, the OP Mapped Point is generally not enabled so it will use OP cam timing but not OP calibration data. I know; it's confusing.
That said, it always uses the torque values in the torque tables, but the logic corrects them for lambda (lambda efficiency), spark timing (S-curves), etc.
Interesting, and the reason we don't use the OP table in gen3 is related to what you guys are discussing correct? When the commanded and actual VVT angles are far off the timing/torque/SD in the OP table will be wrong. So using the standard blending algorithm will be more accurate.
Excuse this very basic question, but the torque tables are a mapping of the engines output torque over RPM and load for a given cam angle pair? From that I would guess if we do something that significantly changes the output power/torque of the motor, then the torque model will be wrong, what is the cascade effect of that?
Last edited by junits15; 05-10-2023 at 12:44 PM.
I have absolutely no idea what I'm doing
The torque model will stay plausible as long as the correlation between torque and inverse stays the same. You can run direct port nitrous and the torque model won't really be affected even though the output was increased substantially (not getting into the O2 sensor part of that, just that the MAF doesnt see it).
Anything that produces more MAF (forced induction) than the airflow model anticipates will break the torque correlation, the most common symptom people see is a throttle closure and/or a limp code (P061B). Technically, the issue isnt the torque table itself, just that you got more load than you asked for. The torque tables are virtual so as long as they correlate, having realistic values arent majorly important (how many Cobb tuned BT FoST's have you seen with zero torque table tuning). This is a can of worms because we all like to fight tooth and nail over the best way to tune around the fact that these PCMs are meant for NA only.
junits15, I honestly don't see any advantage to enabling the OP mapped point. Yes, it allows you to isolate one set of tuning parameters for just WOT use, which makes it easy, but when you move OP cam timing then you have to re-tune the Mapped Point.
At times the, part throttle mostly, the throttle body model and the driver demand table agree on the airflow.
At times, WOT, its beneficial to allow them to vary. Boosted OEM cars, usually they are calibrated not to vary as the TB model will have an inlet pressure sensor instead of assuming constant barometric pressure.
At other times, Idle, the throttle body model is in sonic flow and the model isn't accurate so the engine is controlled mainly by the driver demand and torque to load model. The torue to load and load to torque model is used at all times.This definitely falls into what we are discussing with mapped points weight being the physical cam positions, and snap to lines and points tring to make calculations simpler.
Its confusing because it is complex with the numerous feedback loops and feedforward models. Definitely can be a can of worms because it varys with what you are talking about. Theres three "Torques" you want to familiarize your self with. Scheduled/ indicated torque(TTL/LTT model), Driver demand/ ETC torque(Driver demand table/ throttle body model), and Engine brake torque(calculated based on actual conditions).
The indicated/ scheduled torque is directly controlled by the driver demand/ ETC torque. It is indirectly controlled by the ECU controlling the engine brake torque (like idle, traction control, IPC and other limits).
Unless you are in one of these indirect situations, your goal should be to make engine brake torque equal driver demand. Just like des MAF = MAF sensor. And everything in between including cam actual and desired. The less the system has to fight to correct error, the more "tuned" it is and the better things will perform.
torque control (1).jpg
This picture shows how it takes the engine brake torque(calculated via driver demand/ throttle body model) and determines the desired airflow through the MAF.
It may not be exactly like this, but very close.
Last edited by murfie; 05-11-2023 at 02:24 AM.
This is good to know, and for me its a useful clue in understanding the torque model. From what you're describing, it almost sounds like the absolute modeled torque value isn't important, more just that the torque and inverse tables cover the full range of loads you will see in operation?
I don't plan on re-enabling it, more just trying to understand the rationale behind turning it off. What did they gain by disabling that logic? At least for now, I'm planning on leaving the OP cam path (as I have been calling it) stock, so maybe as a learning tool the OP tables could prove useful. thoughts?
I have absolutely no idea what I'm doing
You know when I decided to learn how to tune this car I never expected to need to remember linear feedback, but here we are lmao. Thank you for the response, I'll admit that there are a lot of things you mentioned that I don't understand, but it helps me know what I need to start reading up on.
It seems like the torque model has a lot more going on than I anticipated, but from that it sounds like tis not something I can overlook if I actually want to tune this correctly.
EDIT: I just came across this post, which is immensely helpful foundational information https://forum.hptuners.com/showthread.php?69606-Late-model-Ford-s-Torque-Control-ETC-System
Last edited by junits15; 05-11-2023 at 10:48 AM.
I have absolutely no idea what I'm doing
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