VVT observations - current vs. advance
06-23-2010, 07:58 AM
#161
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I have dibs on the first one out of production. You can have my first born daughter.
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06-23-2010, 12:04 PM
#163
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I got the whole setup to convert to the Crank and Cam sensors for my VVT motor, I am just to lazy to build the circuit for my MS to understand the signals. So by giving you cash money it saves me energy which is win-win.
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12-08-2010, 05:19 PM
#171
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On the topic of the original post, I'm curious about implementing this as an open loop setup.
I can make a simple 6x6 78Hz (that's the limit on generic outputs) output table and assign it to controlling VVT.
if I wanted to emulate essentially what I discovered (full retard to 2700, full advance 2700-4700, full retard above 4700), would it be as simple as dumping the duty cycles Jason came up with on page fourish....
... into the table at the appropriate RPM? I'm thinking of something like this:
I'm assuming the minimum and maximum duty cycle isn't critical as long as I am below or above them enough to overcome hysteresis. And obviously the "lock" position without closed loop is meaningless.
The only thing I can think that might make a difference is providing a larger RPM gap for the transition from 0 to 60% or 60 to 0, but perhaps I will just try to log the rate of change and see if it's "too fast".
I can make a simple 6x6 78Hz (that's the limit on generic outputs) output table and assign it to controlling VVT.
if I wanted to emulate essentially what I discovered (full retard to 2700, full advance 2700-4700, full retard above 4700), would it be as simple as dumping the duty cycles Jason came up with on page fourish....
Code:
kPa
250 0 0 60 60 0 0
180 0 0 60 60 0 0
120 0 0 60 60 0 0
80 0 0 60 60 0 0
60 0 0 0 0 0 0
20 0 0 0 0 0 0
500 2600 3000 4200 4700 8000 RPM
The only thing I can think that might make a difference is providing a larger RPM gap for the transition from 0 to 60% or 60 to 0, but perhaps I will just try to log the rate of change and see if it's "too fast".
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12-08-2010, 06:08 PM
#173
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No luck at all?
If not, I will just keep pasting the contents of this thread into msextra.com/forums
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12-08-2010, 06:14 PM
#174
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No luck at all. I didn't have a means to measure the actual cam advance/retard, but the feeling was that there wasn't any gain, and I would sometimes get a weird idle, low-speed surging/bucking, the works.
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12-08-2010, 08:35 PM
#175
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It is not possible at all to target any cam phase other than full advance and full retard without closed loop control.
Basically the cam phase is equal to the integral of (the current minus the hold current, plus a random variable, plus hysteresis). Until it hits full advance or full retard.
Basically the cam phase is equal to the integral of (the current minus the hold current, plus a random variable, plus hysteresis). Until it hits full advance or full retard.
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12-08-2010, 10:12 PM
#176
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I only want full advance or retard for now. basically one end or the other of the adjustment.
I understand that the cam advances as long as current is high enough / duty cycle is over a threshold. I also understand that I do nothing and it will retard fully.
So... why wont providing more than the current/duty move the spool valve to the position where oil fills the advance chamber?
I understand that the cam advances as long as current is high enough / duty cycle is over a threshold. I also understand that I do nothing and it will retard fully.
So... why wont providing more than the current/duty move the spool valve to the position where oil fills the advance chamber?
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