[BoostdBoxer]

as the title states I havent much clue to this when it comes to indepth tuning

[elucas730]

Ah, good old control laws. In general, closed loop refers to using some sort of feedback within your control laws. For a tuning example, an ECU can determine, from the oxygen sensors, whether or not the A/F ratio is too rich or too lean, and adjust accordingly. Open loop then obviously refers to a system in which there is no feedback loop.

[GameOver]

Originally Posted by elucas730

Ah, good old control laws. In general, closed loop refers to using some sort of feedback within your control laws. For a tuning example, an ECU can determine, from the oxygen sensors, whether or not the A/F ratio is too rich or too lean, and adjust accordingly. Open loop then obviously refers to a system in which there is no feedback loop.

let me try if I rem correctly :P

Open loop: y(s) --------[ g(s) ] ------------ t(s)

g(s) doesnt change at all.........you hit the gas, engine accelerates, creates power < t(s) >.

Closed loop: y(s) --*-------[ g(s) ] ------------------> t(s)
| |
^ |
| ------------&lt;--[ r(s)] ---&lt;--



so yah here you press on the gas, engine accelerates, output is feeded back to r(s) to make any corrections, the car's ECU, then compared and feeded again to g(s), the engine ....... Id tend to believe that its safer for the car to be in closed loop all the time and let the ECU do its business ....... safety. I guess timing, a/f, and whatever it does.

[GameOver]

Damn, I just think I opened a can of worms.

So does the UTEC make the system go into open loop ?!? &lt;----i dont think its safe

Hmmm, Id tend to believe now that a ECU reflash with new parameters is the safest way to go......let the ECU do its thang.


A block diagram with the UTEC in this control system.....can anyone actually describe what the UTEC does........please.

thank

[Rev]

Sorry I just had to post this:

Closed loop feedback system:



where:




I believe F(s) is where the wastegate and a MBC goes... controlling that the output (boost) doesn't go to infinity. G(s) is the transfer function of the turbocharger.

Reminds me of my Control Engineering I class .. oh my head hurts !

[GameOver]

errrrrrrr, has SOA, Vishnu or TXS released a detailed description. A block diagram.

going back to the utec vs ecu reflash thang

I think that a ecu reflash will improve the ECU's stability when you free up the exhaust and free up the intake. Its possible that these parameters reach their thresholds and make the ECU unstable..........

Im curious now.

G(s) NEVER changes so this would be the engine, fixed bore, stroke, etc. F(s) HAS to be the ECU. MBCs, ported wastegates, full turboback, intake, etc are things added at the input of F(s) inline with each other or in parallel......adding/changing poles/zeros that ALTER F(s)'s designed stability. F(s) has limits too......it has a threshold into which after that it might be unstable and all hell brakes loose; detonation, etc. The ECU isnt able to keep up with these changes. Soooooooooo the fix is to either reflash the ecu with new parameters, a new transfer function, that will have more room for changes in its input without it going unstable.

YESSSSSSS, I rem EE4** YESssssss

I knew I was going to use this someday

C'mon guys lets discuss this and create our OWN ultimate engine management unit

[SabreOfSD]

You know, this thead is making me revert to my EE days... Acutally, more like it makes me spasm after doing my BEE and MEE (geared towards Control Theory)

[Fhqwhgads]

Hmm, I'm guessing you guys are talking about open loop vs. closed loop fuel control (not boost control).

Utec doesn't force it into open loop. Utec adjusts the parameters WHILE it's in open loop. With the ECU's stock parameters, this happens at 63% TPS or 5500 rpm. So basically you're letting the stock ECU adjust for Stoich (14.7:1) AFR while in closed loop (using various sensors) but you get to adjust fuel while in open loop. Now, there's been some problems with the 04's in the switch over point for open loop. Basically, there was some delay with it that caused some tuning problems. I'm not sure how this affects us, since our ECU is completely different.

If you want to force the car into open loop sooner, you need to reflash that threshold TPS value (63% in the stock setting I believe).

Now with the UTEC you also have the ability to go into open/closed loop boost control which is a bit different.

I'm just going off of what I've read on various forums though, so I could be totally wrong. I haven't had the opportunity to really get into the tuning thing (no UTEC yet ) so all of this is IMHO.

[GameOver]

Originally Posted by Fhqwhgads

Hmm, I'm guessing you guys are talking about open loop vs. closed loop fuel control (not boost control).

Utec doesn't force it into open loop. Utec adjusts the parameters WHILE it's in open loop. With the ECU's stock parameters, this happens at 63% TPS or 5500 rpm. So basically you're letting the stock ECU adjust for Stoich (14.7:1) AFR while in closed loop (using various sensors) but you get to adjust fuel while in open loop. Now, there's been some problems with the 04's in the switch over point for open loop. Basically, there was some delay with it that caused some tuning problems. I'm not sure how this affects us, since our ECU is completely different.

If you want to force the car into open loop sooner, you need to reflash that threshold TPS value (63% in the stock setting I believe).

Now with the UTEC you also have the ability to go into open/closed loop boost control which is a bit different.

I'm just going off of what I've read on various forums though, so I could be totally wrong. I haven't had the opportunity to really get into the tuning thing (no UTEC yet ) so all of this is IMHO.

Good info man!