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I'm an MEtech working in an EE's position. I think Bob's an ME as well. That's why we're overanalyzing everything ;)Quote:
Originally Posted by VehiGAZ
I want these plugs soo badly. As it stands, this will not be a fix for the faint of heart. With the plugs, we could build them and just send them out to be plugged in.Quote:
Originally Posted by VehiGAZ
I am at 'work' right now. Getting ready to build the interface cables that I need to test the TOD's ins and outs.
I'll take pictures.
After further review, there is no indisputable conclusive evidence that my analysis of the ball ramp thing is right and the play stands as called on the field by mbeachQuote:
I'm still fairly certain about the ball/ramp's ability to transmit large amounts of torque to the front driveshaft. I thought the same thing about the redundancy of the e-clutch, but I believe that its primary purpose is to proportion/modulate the amount of torque to the front, rather than to simply link the two shafts together. mbeach
Afterall, the techs at Isuzu went through alot of trouble to put the ball-ramp mechanism in there. And SOMETHING had to cause Tone's broken axle. And I certainly don't think it was residual friction from a few ~5 inch disks.
I think someone should call Merlin and see about finding the supplier for those connectors, they would make this a fool-proof modification. Right now I am looking at tapping or modifying 9 different wires (though i am trying to reduce this #). I talked to a contact at Bosch but they weren't very helpful.
mbeach, I drew up my circuit diagram on SmartDraw and am looking it over. I think the next step is to find those PWM values for the solenoid, and Voltage values for the other important wires And while youre in there, some data on the real currents the solenoid is drawing might be helpful to us when it comes time to select timer components. If I had a portable scope I'd be in the VX confirming your numbers but right now I am using aTektronix TDS 210 that is chained to the lab.
VehiGAZ, glad to help, and I hope I got everything right on my analysis.
If only ME's built everything: We'd run out of titanium, parts would start at 1million dollars, everything would fix itself and the world would be bombproof.Quote:
I'm an MEtech working in an EE's position. I think Bob's an ME as well. That's why we're overanalyzing everything
Mechanical Engineering: the definition of 8 gallons in a 5 gallon bucket.
Front driveshaft snapped at about 90MPH on the dyno during my second pass. It broke about 2 inches out the the transfer case (required replacing it also) and was a bit jagged. Made a loud pop when it happened.
I'm working on uploading photos and data (spreadsheets) now. All that I can say is AWESOME.
Everything worked like a charm (a tribute to my cable-building and soldering skills ;) ).
There were some VERY interesting occurences during testing.
Things of note (to get us started before the pictures are up):
-The frequency of the PWM signal to the e-clutch is 50 Hz. Duh, 20 milliseconds. I remember reading that in the literature for the VX.
-In "2wd" mode, below 15% torque to front, the TOD is sending current to the e-clutch. The PWM signal = 3.2V. This is a 22% duty cycle based on my input voltage.
-My voltage into the TOD was 14.0V even. This will skew results a bit, but it still works. Plus the math is easier.
-The pulse width varies with speed, more speed = greater duty cycle, even if it's still in 15% mode. At 30mph, the PWM signal = 5.5V. This is a 39% duty cycle.
-Anything above a 68% duty cycle will put the truck into 4hi (spinning tires, low speed). This signal should be increased proportionately with respect to vehicle speed. At 68%, we are seeing only 9.5V at the e-clutch.
-Contrary to my reading in the patent description, ABS does NOT turn off the 4wd.
I have plenty of photos, plus some screenshots of the scope and TOD in action. I'm trying to put in into my gallery along with an excel file with my data collection.
O.K., this is a bit unrehearsed.
This was the cable that I built to interface to the TOD:
[img]
http://www.vehicross.info/gallery/data/500/thumbs/P2130001.JPG[/img]
This was the cable map, it shows what parameters were monitored:
http://www.vehicross.info/gallery/da...s/cablemap.JPG
Here is the TOD connector:
[img]
http://www.vehicross.info/gallery/data/500/thumbs/TODview.JPG[/img]
I spliced into this with my cable. Connections were made inside of the plugs (which are impossible to dismantle by the way. If anyone knows how to take these things apart, please let me know. I was forced to solder INSIDE of the holes underneath the white clips.)
TOD interface cable, ready to go.http://www.vehicross.info/gallery/da.../Interface.JPG
Here's the road we used for testing. Old Murphy Dome Rd., about 18 miles north of Fairbanks, Alaska. This road starts out as packed gravel, frozen with patches of hard snow and ice. It quickly peters out into a narrow trail, all ruts and deep snow, about 5 feet wide. Yes, I scratched the truck -a lot.
http://www.vehicross.info/gallery/da...bs/OMDroad.JPGhttp://www.vehicross.info/gallery/da...s/GoatPath.JPG
This is my lovely co-driver, whose patience was sorely tested this day. "...I said SPIN the tires woman!"
http://www.vehicross.info/gallery/da.../Co-driver.JPG
This is a scope shot taken at idle, in Neutral (transmission). Notice the pulse width. http://www.vehicross.info/gallery/da...s/GoodIdle.JPG
At 60mph (on ice) in 15% mode:http://www.vehicross.info/gallery/da...umbs/60mph.JPG
Random scope shot:http://www.vehicross.info/gallery/da...bs/15drive.JPG
I need to attach an .xls file. how do I do this?
I have it on pdf now and still can't attach it to the post. What gives?
Here's a caption for the file if I can ever upload it.
"If there's a blank, it was not important enough to fill in. I chose not to mess with the ABS leads after I determined that it had no effect on the TOD. I'm sure that the TOD uses the ABS as an input, but the 4WD Out to the ABS is unreadable.
TPS signal is variable via potentiometer at the throttle. Roughly 0-13V.
The VSSs are weird Hall-effect sensors operating at 4-5V.
The indicators work as explained in the maintenance CD. Switched grounds indicate an "on" state."
You soldering fool! WOW mbeach - you have gone above and beyond the call here! I am truly impressed by what you have done to get this nut cracked.
As for the Excel file, there is a size limit on attachable files, which I ran into when trying to post the ToD patent file. Moncha PM'd me about it, but of course I deleted the PM so I can't tell you what the limit is. But if you have just a data spreadsheet, it shouldn't be running into the size limit. Alternatively, you can try to post it in the Downloads section of the site, but I didn't have much luck with that, either. It seemed to want a URL for the file - I wasn't sure.
So although I absolutely LOATHE drawing conclusions or even being guided in my research by initial data, don't your findings suggest that we shouldn't send a static 68%+ signal to the clutch? That is, wouldn't it potentially be too much when you are accelerating from a stop? Or no?
The difficulties with the wiring harness shouldn't be a big deal. If we just need to tap into one wire (the one going to the ToD clutch), it's just not worth rigging up a dedicated connector. Of course, judging by what you've done already in the cable-making department, I realize you may not agree with me :-). It can still be a simple install to cut the clutch wire and splice in the switchable circuit.
Ok, good luck with the data interpretation! Let us know what else you figure out!
Having the correct plug (we only need one of the two) would make life much easier, and it would look nicer.
As far as I can tell, we only need to cut/intercept 1 wire. The pink TOD to solenoid wire. We will want to 'tap in to' 4 more wires, each for the 3 display segments and one for the AUTO display.
That's 4 taps and one cut. Not too bad, even for a novice. We just have to make sure that everyone uses high-quality taps (if there really is such a thing). Vibration is the enemy of the wire tap (scotch-loc, et al.).
As for the 68% duty cycle for 4wd.
This is a bare minimum number, and at high speed may not be high enough.
The purpose here is not to replace the TOD's logic, we are just trying to modify its outputs. There really is no such thing as overkill as long as we provide a nice 50Hz pulsed signal to the e-clutch.
I say 87-88% duty cycle would work for just about everyone, regardless of battery juice available.
The biggest surprise for me was the presence of voltage at the pink wire when in '2wd'.
I think you're right - a decent margin above 68% will probably do the trick nicely - and if it's not enough to maintain full 4WD-Hi at 60 mph, well, you probably don't really need 4WD in that case anyway.
So, uh, are you going to throw a circuit together, mbeach? And post required parts and directions? Pretty please? Winter's coming here in Connecticut... :-)
I'll try to work on this today. I have a lot of parts available to me that may not be readily accessable for most people.
Today I found a really nice trimmer that would make a cool knob. Very tactile with nice feedback. It felt like a BMW iDrive unit. It could be easily replaced with a 2k ohm potentiometer from Radio Shack though.
I'm trying to make it as simple as possible for everyone to build/commission to build.
Reality is, all we did here was to confirm the work that the Terracan guys did. I never was able to look at the links, but from Bob's first post, it sounds like we have just done our own version of the same thing.
I can't take any credit for this, but I assure you that a VX ready solution will be on the way asap.
I'd still like to share my spreadsheet, but I think that we can get started without it.
It appears that there is a mass-produced PWM controller that will suit our needs. All we need now is a pot, a knob, and the ability to ground the indicator lights at will. This can be done through the same pot(entiometer) that selects the 4wd mode.
It's getting easier and cheaper by the day.
mbeach, if this works, and its simple enough for me to pull off in an afternoon's worth of work....
I'll fly out to Alaska and kiss you.
Ha, I'll pass on the man-love -but thanks anyways.
Actually, when I stated looking back through old posts, it hit me that we (the board) were on to a solution a long time ago.
Especially in this post by SGT. Batguano:
"It may be a Pulse Width Modulated signal, like the speed signal, which is why no one has come up with a soultion to the top speed limiter of our ecu.
I may be wrong, but I've been under the impression that you can use a dc motor controller on a pwm circuit. So, I'm wondering if one could replace the rheostat or variable resistor on the dc controller board with a 4-position switch and four fixed value resistors."
And that's exactly what I've come around to. I found a DC motor/fan/lamp PWM controller that will work nicely, and only cost between $40 and $50.
That unit, a switch to activate MANUAL mode, and a rotary switch (no longer a potentiometer -long story) to select the modes and we are looking at a $75 mod, depending on how fancy you want to make it look.
I'm ordering a PWM controller from Critical Velocity today for testing.
I realize this is an old and probably dead thread, but did this ever work?
I'd also like to know. Although I realize that the odds are that even if someone who pulled it off still has his/her vx, they aren't apt to post on this forum anymore.
Yeah, but maybe someone knows someone who knows someone else? LOL!
There is a physical ball ramp mechanism in the way of ever governing the TOD with merely electrical switching. Everybody who has tried didn't succeed. You can get a Trooper unit and install it easier. The VX was a deluxe Trooper , and a key selling point was it would always be instantly ready for whatever the terrain and weather threw at it.Quote:
Originally Posted by Thelgord
If you have to turn it off and on manually it wouldn't be always ready to react.
Sorry.