- Sat Jun 04, 2016 4:51 am
#8568
So, your permutations are basically (number of solenoids) ^ 2. 1 solenoid = 2 possible; 2 solenoids = 4 possible; 5 solenoids = 32.
I'd argue that for most situations, some solenoid permutations are mutually exclusive, i.e. you wouldn't engage both 1st gear and 3rd gear solenoids at the same time, nor would you actuate reverse and any other solenoid simultaneously, and again you would lock up the torque converter in any gear other than the highest forward gear. So, essentially, you would have only two solenoids powered simultaneously, basically when up or downshifting or when in top gear with overdrive, no?
Such conflicting conditions, if they're not disallowed early in the firmware operation, must be denied before any solenoid state is changed. In a similar vein, even if the user tries to force a gear change, the unit should deny any change that results in either engine over or under speed conditions.
I'd argue that for most situations, some solenoid permutations are mutually exclusive, i.e. you wouldn't engage both 1st gear and 3rd gear solenoids at the same time, nor would you actuate reverse and any other solenoid simultaneously, and again you would lock up the torque converter in any gear other than the highest forward gear. So, essentially, you would have only two solenoids powered simultaneously, basically when up or downshifting or when in top gear with overdrive, no?
Such conflicting conditions, if they're not disallowed early in the firmware operation, must be denied before any solenoid state is changed. In a similar vein, even if the user tries to force a gear change, the unit should deny any change that results in either engine over or under speed conditions.
PSIG wrote:I'm thinking the digital inputs should be whatever is most foolproof, so perhaps opto. Those inputs have been called-out by others. As planning placeholders, I would designate PWM outputs for TCC (lockup) and EPS (pressure), and digital outs for Reverse, Reverse Lights, and Start-Safety switch (neutral/park or NSS). Even with one more hi-amp digital for "other", that leaves four to operate shift solenoids, which (in most designs) translates to permutations of 16 gears as I calculated below, and does not even consider using the low-outs instead. My 4-speed OD trans with lockup uses four solenoids for everything (one pressure, one TCC, and two shift), plus one optional for reverse lights. Default is 2nd gear and max line pressure for limp-home with no solenoid inputs (disconnected controller {0,0}) for example.
Number of shift solenoids permutated to number of possible transmission gears:
Solenoids: 1
Permutations: 2
{0} {1}
Solenoids: 2
Permutations: 4
{0,0} {0,1} {1,0} {1,1}
Solenoids: 3
Permutations: 8
{0,0,0} {0,0,1} {0,1,0} {0,1,1} {1,0,0} {1,0,1} {1,1,0} {1,1,1}
Solenoids: 4
Permutations: 16
{0,0,0,0} {0,0,0,1} {0,0,1,0} {0,0,1,1} {0,1,0,0} {0,1,0,1} {0,1,1,0} {0,1,1,1} {1,0,0,0} {1,0,0,1} {1,0,1,0} {1,0,1,1} {1,1,0,0} {1,1,0,1} {1,1,1,0} {1,1,1,1}
Solenoids: 5
Permutations: 32
{0,0,0,0,0} {0,0,0,0,1} {0,0,0,1,0} {0,0,0,1,1} {0,0,1,0,0} {0,0,1,0,1} {0,0,1,1,0} {0,0,1,1,1} {0,1,0,0,0} {0,1,0,0,1} {0,1,0,1,0} {0,1,0,1,1} {0,1,1,0,0} {0,1,1,0,1} {0,1,1,1,0} {0,1,1,1,1} {1,0,0,0,0} {1,0,0,0,1} {1,0,0,1,0} {1,0,0,1,1} {1,0,1,0,0} {1,0,1,0,1} {1,0,1,1,0} {1,0,1,1,1} {1,1,0,0,0} {1,1,0,0,1} {1,1,0,1,0} {1,1,0,1,1} {1,1,1,0,0} {1,1,1,0,1} {1,1,1,1,0} {1,1,1,1,1}
Low-out placeholders (if all outs are either hi or low amp) could be speedometer (dig and analog), pressure, temp, etc.
David