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Old 04-04-2006, 02:34 AM   #1
Spec C Wannabe
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Default Does Hydra have Close Loop Control?

Does Hydra control engine's idle and low-rpm operation via close-loop control?

If so, which control scheme are you guys using? OL or CL?
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Old 04-04-2006, 09:48 AM   #2
jblaine
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You can use whatever you want, OL or CL.
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Old 04-04-2006, 11:10 AM   #3
Element Tuning
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The Element Hydra EMS has a number of closed loop fueling options:

Closed loop "14.7:1 AFR" utilizing the OEM rear 02 sensor. This is definable with a start and end rpm plus a load range within vacuum.

Closed loop "14.7:1 AFR" utilizing the Hydra WB 02 sensor. This is definable with a start and end rpm plus a load range within vacuum.

Closed loop "Wideband Target Table" utilizing the Hydra WB 02 sensor. This is definable with a start and end rpm plus all load ranges including boost. The target AFR is defined by a 32x32 ""Wideband Target Table" so you can decide what AFR you want to run for a given load and rpm.

Closed loop/AutoTune "Wideband Target Table" utilizing the Hydra WB 02 sensor. This is definable with a start and end rpm plus all load ranges including boost. The target AFR is defined by a 32x32 ""Wideband Target Table" so you can decide what AFR you want to run for a given load and rpm. The difference here is that this alters the fuel map permanently by tuning the fuel table until the AFR matches those set in the "Wideband Target Table."

Whatever is outside of either your rpm range or load range is then open loop fuel control.

Thanks,
Phil
www.elementtuning.com
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Old 04-05-2006, 02:13 AM   #4
Spec C Wannabe
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Thank you Phil for your answer.

So I need an optional Hydra WB O2 sensor for the type 2-4 close loop control.

Question for Type 3 CL. To make it a real Close Loop control, the ecu has to constantly adjust AFR using feedbacks from Hydra WB O2.

Can the system (as a whole) adjust AFR fast enough in higher rpm range?
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Old 04-05-2006, 12:45 PM   #5
entropy138
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How 'high' of an rpm range are you looking for it to remain CL?

I've had mine set at 4300rpm (based on the setup guide) and observed it using the STT (short term trim i'm assuming) to keep it right near 14.7 and after Phil tuned it he set it at 3800 rpm for various reasons...
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Old 04-05-2006, 04:41 PM   #6
Element Tuning
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Quote:
Originally Posted by Spec C Wannabe
Thank you Phil for your answer.

So I need an optional Hydra WB O2 sensor for the type 2-4 close loop control.

Question for Type 3 CL. To make it a real Close Loop control, the ecu has to constantly adjust AFR using feedbacks from Hydra WB O2.

Can the system (as a whole) adjust AFR fast enough in higher rpm range?
The main point of a closed loop fueling system is to adjust for environmental and other influences that can affect the fueling of an open loop system. You really need to make sure your fuel maps are in the ball park, so within about .3 AFR. It's more than adequate for situations such as this.

For tuning purposes the "Autotune" rate can be defined based on rpm. The higher the value the faster and more aggressive the "Autotune" system can react to off target AFRs. So for tuning purposes the “Autotune/closed loop” can be fine tailors to react quickly to substantially off target AFRs but to use “Autotune” your laptop must be connected.

Thanks,
Phil
http://www.elementtuning.com
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Old 04-05-2006, 05:17 PM   #7
Element Tuning
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Quote:
Originally Posted by entropy138
How 'high' of an rpm range are you looking for it to remain CL?

I've had mine set at 4300rpm (based on the setup guide) and observed it using the STT (short term trim i'm assuming) to keep it right near 14.7 and after Phil tuned it he set it at 3800 rpm for various reasons...
Yes, you don’t want the closed loop fuel control on for all rpm ranges unless you are using “Autotune.” When I tune cars I set the “closed loop” to “Wideband Target Table” which has closed loop feedback even into boost. You just want to make sure that you revert to “open loop” fuel by about peak boost incase there is a WB failure. This delivers consistent, smooth, and great fuel economy since there is an AFR feedback under most driving conditions.

Thanks,
Phil
http://www.elementtuning.com
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Old 04-07-2006, 11:25 AM   #8
Spec C Wannabe
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Quote:
Originally Posted by entropy138
How 'high' of an rpm range are you looking for it to remain CL?

I've had mine set at 4300rpm (based on the setup guide) and observed it using the STT (short term trim i'm assuming) to keep it right near 14.7 and after Phil tuned it he set it at 3800 rpm for various reasons...
What sensor do you use to get AFR feedback? A stock rear O2 sensor or Hydra WB O2

Reason I ask about this topic is bacause I want fuel economy from CLF and power from OLF when i step on it.

Thanks
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Old 04-07-2006, 01:59 PM   #9
bboy
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It can be either sensor for closed loop. Running closed loop will target an AFR of 14.7.

Running in Autotune all the time (not practical with a laptop plugged in) will target whatever AFR is in the Target Table. You need a wide band to run in Autotune.

Low RPM, (idle) is controlled by at PID feedback loop coupled to a min/max PWM.

This is not a UTEC with all the open loop/closed loop transition crap.
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Old 04-07-2006, 02:12 PM   #10
Master2192
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Quote:
Originally Posted by Spec C Wannabe
What sensor do you use to get AFR feedback? A stock rear O2 sensor or Hydra WB O2

Reason I ask about this topic is bacause I want fuel economy from CLF and power from OLF when i step on it.

Thanks
When you setup CLF, you setup the rpm ranges that it'll work in as well as manifold pressure. When you step on it, it'll swtich to OLF depending on your settings.

I would use the Hydra WB O2 to tune your Open Loop fuel maps, after you've got it all dialed in, then take it out and switch to using the rear O2 sensor for CLF. I would do it this way because WideBand O2 sensors are known to have much shorter lifespans compared to regular O2 sensors.
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Old 04-07-2006, 02:51 PM   #11
Element Tuning
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Location: 673 WHP Element ProComp Engine
Default

Quote:
Originally Posted by Spec C Wannabe
What sensor do you use to get AFR feedback? A stock rear O2 sensor or Hydra WB O2

Reason I ask about this topic is bacause I want fuel economy from CLF and power from OLF when i step on it.

Thanks
You can use either sensor for closed loop fuel control. Re-read my post which explains what parameters you can use "closed loop" for given the sensor you choose to utilize. With the OEM sensor your only choice is 14.7:1 AFR but with the WB you can choose whatever AFR you prefer at a given load and rpm.

Thanks,
Phil
www.elementtuning.com
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