CAJ Innovations Forums - Ethanol

sign216

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Re: Ethanol - Map Adjustment?
Reply #15 - 04/28/12 at 09:28:01

Raz and Luhbo, my equipment is different. I have an 09 V7 with a factory narrow band sensor. My MyECU module is a later one, that shows the O2 sensor output as a voltage from 0 to 1 (although 5 is listed as a possible maximum).

I made a mistake in my previous posting. I think reducing the O2 target voltage makes the air fuel ratio (AFR) leaner. I did two runs, logging both, with two different O2 volt adjustments (-4, +4). It seemed to run better with the +4 map, but I'm not an unbiased observer.

I'm having a little trouble reading the data logs. I'll put that in another post, it will be more "searchable" for the next guy starting out.

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Re: Ethanol - Map Adjustment?
Reply #16 - 04/28/12 at 09:38:38

The factory narrow band sensors are a small step up from the earlier narrow band sensors. There is some gradual curve.
You should stick with the voltage targets in the original map that I use on my Breva 750

Did you change the targets from +ve to -ve ? You can't do that. The sign is to reflect they slope of the curve from the sensor. +ve is for the richer is a higher voltage.
Using the correct sign will give closed loop operation. Using the wrong sign will just peg the compensation at + or - 25%

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sign216

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Re: Ethanol - Map Adjustment?
Reply #17 - 04/29/12 at 08:24:39

YaBB Administrator wrote on 04/28/12 at 09:38:38:

The factory narrow band sensors are a small step up from the earlier narrow band sensors. There is some gradual curve.
You should stick with the voltage targets in the original map that I use on my Breva 750

Did you change the targets from +ve to -ve ? You can't do that. The sign is to reflect they slope of the curve from the sensor. +ve is for the richer is a higher voltage.
Using the correct sign will give closed loop operation. Using the wrong sign will just peg the compensation at + or - 25%

I didn't change any signs, - or +. When I wrote -4, I meant a 0.04 volt decrease of the target voltage. i.e. 0.81 instead of 0.85.

E10 fuel operates best with a 4% richer mixture. Yea, you can ignore it and be happy with slightly diminished performance. But being happy with "slightly diminished performance" isn't what MyECU is all about, is it?

MyECU allows a rider to account for the variations of his conditions, and I'd like to take advantage of that.

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raz

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Re: Ethanol - Map Adjustment?
Reply #18 - 04/29/12 at 08:43:53

sign216 wrote on 04/29/12 at 08:24:39:

E10 fuel operates best with a 4% richer mixture. Yea, you can ignore it and be happy with slightly diminished performance. But being happy with "slightly diminished performance" isn't what MyECU is all about, is it?

I'm all for it. But your sensor (even if it's a narrowband) reads lambda. And your targets are lambda (no matter in what form they are represented). So if you go from pure gasoline to E10, your targets (if correct in the first place) will need no change: Your closed loop system will end up with a 4% richer mixture if that is what's needed. This is the whole point of running closed loop.

Raz

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« Last Edit: 04/29/12 at 08:46:14 by raz »

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sign216

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Re: Ethanol - Map Adjustment?
Reply #19 - 04/29/12 at 09:08:08

raz wrote on 04/29/12 at 08:43:53:

sign216 wrote on 04/29/12 at 08:24:39:

E10 fuel operates best with a 4% richer mixture. Yea, you can ignore it and be happy with slightly diminished performance. But being happy with "slightly diminished performance" isn't what MyECU is all about, is it?

I'm all for it. But your sensor (even if it's a narrowband) reads lambda. And your targets are lambda (no matter in what form they are represented). So if you go from pure gasoline to E10, your targets (if correct in the first place) will need no change: Your closed loop system will end up with a 4% richer mixture if that is what's needed. This is the whole point of running closed loop.

Raz

The lambda target is set up for pure gasoline. E10 has a different stoichiometry. Here are the different AFRs;

Gasoline at 1:14.7
E-10 at 1:14.1

The O2 sensor will give you an adjustment, but it's trying to get you to 1:14.7, which isn't what E10 needs.

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raz

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Re: Ethanol - Map Adjustment?
Reply #20 - 04/29/12 at 09:12:46

sign216 wrote on 04/29/12 at 09:08:08:

raz wrote on 04/29/12 at 08:43:53:

sign216 wrote on 04/29/12 at 08:24:39:

E10 fuel operates best with a 4% richer mixture. Yea, you can ignore it and be happy with slightly diminished performance. But being happy with "slightly diminished performance" isn't what MyECU is all about, is it?

I'm all for it. But your sensor (even if it's a narrowband) reads lambda. And your targets are lambda (no matter in what form they are represented). So if you go from pure gasoline to E10, your targets (if correct in the first place) will need no change: Your closed loop system will end up with a 4% richer mixture if that is what's needed. This is the whole point of running closed loop.

Raz

The lambda target is set up for pure gasoline. E10 has a different stoichiometry. Here are the different AFRs;

Gasoline at 1:14.7
E-10 at 1:14.1

The O2 sensor will give you an adjustment, but it's trying to get you to 1:14.7, which isn't what E10 needs.

I'm afraid you totally miss my point.

Gasoline needs an A/F ratio of 14.7 to get lambda 1.
E10 needs an A/F ratio of 14.1 to get lambda 1.

Your closed loop system reads, writes, eats and speaks lambda. That means if you have targets that work fine for gasoline, they will work fine for E10. And they will automatically do the very adjustment you speak about.

Raz

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sign216

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Re: Ethanol - Map Adjustment?
Reply #21 - 04/29/12 at 22:41:34

Raz, the lambda ratio that signifies "1" is different for different fuels. For gasoline it's 14.7 to 1. For pure ethanol it's 9 to 1. See here: http://moodle.student.cnwl.ac.uk/moodledata_shared/cdx%20etextbook/dswmedia/fuel...

Since 1999, many modern, sophisticated engines (not Guzzi) designed to run alcohol fuels have sensors that estimate alcohol content and adjust the engine's parameters for ethanol blends. This is called a closed loop system with adaptive learning. See this paper from the Nat. Renewable Energy Lab http://www.nrel.gov/docs/fy03osti/32206.pdf

Ethanol exhaust has different characteristics (see this Swedish paper http://www.best-europe.org/upload/BEST_documents/environment/Exhaust%20emission0... ), and using an oxygen sensor/ECU set for gasoline will give slightly less power. Our Guzzis are designed for pure gasoline, and set so that lambda 1 achieves a gasoline ratio. Ethanol blends require an adjustment to reach gasoline-like performance levels.

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raz

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Re: Ethanol - Map Adjustment?
Reply #22 - 04/29/12 at 22:56:44

sign216 wrote on 04/29/12 at 22:41:34:

Raz, the lambda ratio that signifies "1" is different for different fuels. For gasoline it's 14.7 to 1. For pure ethanol it's 9 to 1.

You are still totally missing my point. Let's say you have a target for pure gasoline. Even if you think of it as AFR 13.2, the target is really Lambda 0.9.

Now, run your engine on pure ethanol. Your target is still Lambda 0.9 so without you changing anything, your target is already equivalent of an AFR of 8.1 for this fuel.

If you'd say you want to enrich the base map by 4%, I'd say go ahead. But do not change the targets.

Raz

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« Last Edit: 04/29/12 at 23:02:16 by raz »

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sign216

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Re: Ethanol - Map Adjustment?
Reply #23 - 04/30/12 at 00:00:09

I apologize. I did miss your point, and misunderstand what the O2 sensor targets were. I thought they were actual voltages from the O2 sensor, and not a % of Lambda.

Some time ago I built a o2 sensor modification that adjusted sensor voltage to enrichen the mix, and I'm accustomed to looking at O2 sensor data in terms of voltage.

I've dropped that mod to go after the broader capabilities of MyECU.
Thanks for your help. With the original map I'll log runs, and see if the data points to map adjustments.

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raz Senior Member Offline Guzzi 11OO Sport, My16MkV, Innovate LC-1 Posts: 373 Stockholm, Sweden Gender:	Re: Ethanol - Map Adjustment? Reply #24 - 04/30/12 at 03:03:19 sign216 wrote on 04/30/12 at 00:00:09: I apologize. I did miss your point, and misunderstand what the O2 sensor targets were. I thought they were actual voltages from the O2 sensor, and not a % of Lambda. Oh, but they are the actual voltages. It's just that they represent lambda, not A/F. Raz
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sign216

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Re: Ethanol - Map Adjustment?
Reply #25 - 05/01/12 at 10:09:49

raz wrote on 04/30/12 at 03:03:19:

sign216 wrote on 04/30/12 at 00:00:09:

I apologize. I did miss your point, and misunderstand what the O2 sensor targets were. I thought they were actual voltages from the O2 sensor, and not a % of Lambda.

Oh, but they are the actual voltages. It's just that they represent lambda, not A/F.

Raz

We aren't communicating well.

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