A synchronous shift doesn't provide any more engagement time than a non-sync shift.

I've only seen charts that show idle and stall. Never anything in between. I think this is where you'll need to do hands on tuning.

When I did that type of work I had a torque sensor on the driveshaft so that I could calculate the energy for each shift. I also had a pressure sensor reading each clutch pressure. I used a graphics program to graph the data.

Yes, that's right.

I don't know if that would be useful or not.

 

I was thinking shift overlap. I would imagine that with a synchronous shift you could reduce it to almost nothing.

 

Will the later range selector physically swap to an earlier trans? Since I have the ability to do either or I'd rather have the later digital setup. Seems less error prone.

 

Yes it will. The mounts are identical.

 

Ok, found someone else that seems to think 585hz is a good PWM frequency for the EPC...

Not sure how or where that came from - I hope personal experience with using PWM to run the EPC... But a starting point is a starting point...

 

I don't think that you will have enough control of the EPC with PWM in an E4OD. The pulse width required between full pressure and zero pressure will be very small, and you won't have the resolution to control the pressure correctly.

 

The way MS works is PWM the path to ground which changes the voltage based on the PWM duty cycle. By changing the voltage in a fixed resistance circuit I essentially change the current. That's how ford controls the EPC, by varying the current.

12v --> Solenoid --> PWM --> Grnd.

It uses a TIP120 NPN transistor for control.

I don't see what's different between an EPC solenoid in a GM 4L80e and the EPC solenoid in the E4OD. The MS runs the 4L80e fine.

 

Pulse Width Modulation controls the average power to a device by applying full voltage to the device for a limited time then Zero Voltage for the rest of the cycle. A 50% Duty Cycle PWM would have the Voltage at full for half the time, and zero for the rest of the cycle. A solenoid is Inductive, not simply a fixed resistor, but we can consider it as a fixed resistor for this analysis.

A Current Controlled system sets a current and changes it as the the conditions change.

The problem occurs when low duty cycle pulses as required for control, the E4OD fluid system is not designed to respond to low duty cycle pulses.

The 4R100 uses PWM, and the fluid system has been modified for PWM.

 

I'm still researching this but I haven't seen anything relating to changes in the EPC for PWM/non-PWM.

I do see a change for the torque converter which changed to PWM and without a lot of work can't be converted from non-PWM to PWM. Including fluid passage changes. The main difference there isn't that the solenoid has trouble, but you no longer need a hydraulic means to control converter lockup speed. With a PWM TC you can vary the duty cycle and thus would want a wide open flow that you could throttle with the solenoid. With the earlier system it's just on or off and there is no point in PWM because it's only going to lock up at a certain rate and PWM will slow that down more.

The EPC is normally closed and at max line pressure. Current is applied to open the valve to bleed pressure off.

Not seeing how the fluid system on the EPC has anything to do with it. Unless PWM can't open the solenoid and stably keep it open.

Mark, do you know of any differences in the EPC fluid passages between the E4OD and the 4R100? Did they switch the 4R100 to PWM for the EPC?

 

You are right. I am confusing the TCC with the EPC. I have put a lot of effort into EPC Current Control, but if PWM will work, it will simplify my hardware.

 

With a high enough frequency I don't see how the solenoid can tell the difference.

The other way to do it is to measure the current and vary the voltage as needed but you're dumping a lot of energy into heat that way. PWM is more efficient.

Here's the PWM circuit info for GPIO. GPIO PWM Output Circuits

I'm sure I mentioned it but I'll say it again, I also plan on using a pressure transducer to directly measure the line pressure and datalog it so I can use that to directly tune the trans for the line pressures I want. Or at least that's the theory...

I feel that if I get the right frequency and duty cycle I should have no problem controlling what amounts to a calibrated leak...

 

The EPC circuit is the same on the E4OD and the 4R100.

To the best of my knowledge no Ford product ever used a PWM EPC.

 

Good to know.

And we're back to the question of the day... Can you control an E4OD EPC solenoid with PWM. You can in other transmissions - the GM 4L60 and 4L80 to be specific. Also the FWD Chrysler 41te. There are others that are not documented but mentioned in the forms.

From what I'm learning it comes down to frequency. At lower frequencies 0-200hz the solenoid can respond with it's full stroke. At higher frequencies 200-1000hz it can't. So you get a proportional control. This is general information about solenoids but I feel it should apply here.

I've been told the frequency to use in the GPIO/MegaShift settings is 585hz. I'm still learning about MS and how it relates to the solenoid control on the EPC circuit but I think the frequency is the clock frequency that it runs at when on. The difference between on and off time is the duty cycle and the higher the duty cycle the higher the opening of the solenoid.

I'm confident enough at this point to move forward. Now all I have to do is get the trans out of the donor truck, settle on TFI or EDIS for ignition control on my EFI conversion for my 86. Do the EFI conversion and stick the trans in, build the GPIO board and install that... So basically all that's left is everything... I wish I could just run out there and test it right now but it's going to be a while...

 

The EPC is not really a Solenoid, but a proportional valve. It opens in proportion to the current in it's coil. It operates in the same manner as 0 to 20 millamp Industrial Control Valves.

The current generates a magnetic field, that drives the valve against it's spring.
In an Inductive Component Voltage leads Current, so short pulses may not be as effective as long pulses. The result will not be linear, but you might be able to generate a curve.

The way to find out for sure is to try it. I'm going to continue with the Current Control circuit.

 

It's a proportional solenoid and they do have them that are controlled by PWM. So the question isn't can PWM control a proportional solenoid but can it control the solenoid in the E4OD...

I'm going to try it. I'm reasonable sure at this point that it'll work. I'll post updates when I get to that point.