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#797976 - 08/27/12 09:48 AM Re: Wideband O2 Project [Re: roger 04 rt]
mneblett Online
Member

Registered: 04/20/09
Posts: 289
Loc: Fairfax, VA
To be clear: Is it correct that this approach still requires the LC-1 to spoof the engine computer to get to the 13.8:1 AF ratio? In other words, no Booster Plug, yes LC-1, yes fuel pressure regulator?

BTW - thanks again for your continued investigations -- this appears to be the "cleanest" set-up so far. I'm about to rebuild my 95K '04 RT-P, so this could not be any more timely for me!
_________________________
Mark Neblett
Fairfax, VA

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#798035 - 08/27/12 12:56 PM Re: Wideband O2 Project [Re: roger 04 rt]
roger 04 rt Offline
Member

Registered: 11/27/11
Posts: 1814
Loc: Massachusetts
Good questions.

Before answering, and I'm sure you know this, I can only answer this question in the context of a stock motorcycle--stock intake, stock exhaust, stock Coding Plug, no other fuel injection changes. A bike should be well tuned, have good coils, good compression, good fuel hoses and pump and no defects.

With that proviso:

1) Closed Loop operation brings many benefits that have been discussed throughout the thread. The Motronic fuel tables are designed for an AFR of 14.7:1 but the Motronic algorithms are designed to converge around ANY transition point of the O2 sensor. The stock sensor transitions from 200 mV to 800 mV at an air-fuel ratio of 14.7:1. The LC-1 can be programmed to make that transition at ANY air-fuel ratio. Therefore to keep Closed Loop but move to another AFR you need something like the LC-1. A point I will make is that this is in no way "spoofing" the Motronic--it giving it a different switching point and working within it's design parameters.

A side benefit to the LC-1 is that you can always read your motorcycle's AFR. I have found this to be a very helpful diagnostic tool.

2. Since the stock fuel map is set for 14.7:1 at cruise, whether you shift the map using a fuel pressure regulator or an IAT shifting device is mostly a matter of choice. The closer your fuel table is to the O2 switch point, the smoother your engine runs while you wait for the Motronic to create its Adaptation Values.

Running the leaner E10 fuel, the Motronic has to adapt 10% to get from 14.7 (where it is starting) to 13.8. A BoosterPlug shifts things 6%, a fuel pressure regulator can shift things 10%.

Another example though would go like this, you're running gasoline with no Ethanol and moving from 14.7 to 14.1 (4% richer, it runs nicely there too). For this, you need only a 4% move.

3. Lastly, there is the Open Loop option. You lose the regulating benefits of Closed Loop. If you run gasoline, without ethanol, a BoosterPlug will get you about 6% richer, good enough for some.

If you run fuel with ethanol and add a BoosterPlug you only end up 2% richer than 14.7. I doubt you would notice the difference.

So running E10 and looking for a richer mixture Open Loop, I would go the fuel pressure route.

The problem with all the Open Loop options is that you have no way for sure to know what AFR you've ended up at. And like running a Techlusion, you have to use the "butt dyno". method.

My favorite for E10 Land:
LC-1 and Fuel Pressure boost to 52 psi

My favorite for Gasoline Land
LC-1 and a BoosterPlug because the BP is easier to install.

A compromise for E10 Land
LC-1 and BoosterPlug

This is probably a longer answer than you hoped for but there are several things to consider.

RB

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#798062 - 08/27/12 03:37 PM Re: Wideband O2 Project [Re: roger 04 rt]
JamesW Online
Member

Registered: 11/23/04
Posts: 802
Loc: Baker City, Oregon
Top of the afternoon to you Roger,
Thing I am having trouble with is this: You have an LC-1 installed with associated wideband O2 sensor. With this combo you can select an A/F ratio of say..13.8/1 which will be the A/F ratio when the Motronic goes into closed loop, all well and good. Now you have increased the fuel pressure to the injectors which will result in a richer mixture both in open and closed loop. Seems to me that the Motronic will simply overcome the extra fuel added by pressure by shortening the on time of the injectors when in closed loop thus returning the A/F ratio to 13.8/1 so not much is accomplished when in closed loop over just running with the LC-1. I can see where the extra pressure will richen things up when running in open loop but I can't see how this would benefit actual performance over the Booster Plug and adjusting the TPS to .40 volts at idle. Am I coprrect in assuming that you are increasing pressure only to richen things up further when in open loop? You know I honestly can't tell much if any difference in performance between E10 and non-ethanol which I use most of the time mainly because my motorcycles are not ridden in winter and the corrosive effects of ethanol I can live without. Even use non-ethanol in my lawn mower (Honda). rofl Just got back from a couple day ride where I used whatever gas was available and did not notice a decrease in performance or any surging. Was on my R1100RSL for this ride. Oh, I should also mention again that I have the O2 sensors disconnected thus am always in open loop.

As a side note: I might just part with my '04RT as I seldom ride it after finding the '94RSL. The RSL is really growing on me. I like the light feel and superb handling in the twisties.

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#798063 - 08/27/12 03:38 PM Re: Wideband O2 Project [Re: roger 04 rt]
legarem Offline
Member

Registered: 08/21/10
Posts: 182
Loc: Quebec, Canada
Hi Roger

For testing purpose, here is an idea.

if we know how many millivolts the O2 sensor sends to the Motronic to get a air/fuel ratio of 13.8, Could it be a good idea to build a precise regulator to feed the Motronic O2 inlet to the required voltage to get a 13.8 AFR ?

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#798087 - 08/27/12 05:51 PM Re: Wideband O2 Project [Re: legarem]
TestPilot Offline
Member

Registered: 05/27/07
Posts: 450
Loc: Williamsville, NY
Originally Posted By: legarem
Hi Roger

For testing purpose, here is an idea.

if we know how many millivolts the O2 sensor sends to the Motronic to get a air/fuel ratio of 13.8, Could it be a good idea to build a precise regulator to feed the Motronic O2 inlet to the required voltage to get a 13.8 AFR ?



That won't work. Feeding the ECU a constant voltage from the O2 sensor means the ECU will thing the AFR is correct no matter what it really is.
_________________________
Karl
2007 R1200ST

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#798089 - 08/27/12 06:20 PM Re: Wideband O2 Project [Re: TestPilot]
smiller Offline
Member

Registered: 03/27/04
Posts: 12236
Loc: Asheville, NC
Originally Posted By: TestPilot
That won't work. Feeding the ECU a constant voltage from the O2 sensor means the ECU will thing the AFR is correct no matter what it really is.

Since a constant voltage is illegal the ECU wouldn't think the AFR is correct, rather it would think that the O2 sensor is faulty and set a fault code and stay in open loop.

But either way, no, it wouldn't work. You maybe could build a circuit that spoofed the ECU by mimicking the correct O2 duty cycle.

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#798150 - 08/27/12 10:05 PM Re: Wideband O2 Project [Re: JamesW]
roger 04 rt Offline
Member

Registered: 11/27/11
Posts: 1814
Loc: Massachusetts
Originally Posted By: JamesW
Top of the afternoon to you Roger,
Thing I am having trouble with is this: You have an LC-1 installed with associated wideband O2 sensor. With this combo you can select an A/F ratio of say..13.8/1 which will be the A/F ratio when the Motronic goes into closed loop, all well and good. Now you have increased the fuel pressure to the injectors which will result in a richer mixture both in open and closed loop. Seems to me that the Motronic will simply overcome the extra fuel added by pressure by shortening the on time of the injectors when in closed loop thus returning the A/F ratio to 13.8/1 so not much is accomplished when in closed loop over just running with the LC-1. I can see where the extra pressure will richen things up when running in open loop but I can't see how this would benefit actual performance over the Booster Plug and adjusting the TPS to .40 volts at idle. Am I coprrect in assuming that you are increasing pressure only to richen things up further when in open loop? You know I honestly can't tell much if any difference in performance between E10 and non-ethanol which I use most of the time mainly because my motorcycles are not ridden in winter and the corrosive effects of ethanol I can live without. Even use non-ethanol in my lawn mower (Honda). rofl Just got back from a couple day ride where I used whatever gas was available and did not notice a decrease in performance or any surging. Was on my R1100RSL for this ride. Oh, I should also mention again that I have the O2 sensors disconnected thus am always in open loop.

As a side note: I might just part with my '04RT as I seldom ride it after finding the '94RSL. The RSL is really growing on me. I like the light feel and superb handling in the twisties.


The easiest way to think of this is that the Motronic requires the least Adapttion when the switch point of the O2 sensor 13.8:1 and the fuel maps (factory set to 14.7 at cruise) are the same. By boosting the fuel pressure I've made the times in the stock fuel map produce fueling like they had been designed for 13.8.

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#798151 - 08/27/12 10:12 PM Re: Wideband O2 Project [Re: legarem]
roger 04 rt Offline
Member

Registered: 11/27/11
Posts: 1814
Loc: Massachusetts
Originally Posted By: legarem
Hi Roger

For testing purpose, here is an idea.

if we know how many millivolts the O2 sensor sends to the Motronic to get a air/fuel ratio of 13.8, Could it be a good idea to build a precise regulator to feed the Motronic O2 inlet to the required voltage to get a 13.8 AFR ?



It would be great if it worked that way but the only thing the Motronic tries to figure out from the O2 sensor is whether the mixture is richer or leaner than the switch point of the O2 sensor. To change that switch point you need a different O2 sensor, one that switches at other than stock 14.7:1.

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#798152 - 08/27/12 10:17 PM Re: Wideband O2 Project [Re: smiller]
roger 04 rt Offline
Member

Registered: 11/27/11
Posts: 1814
Loc: Massachusetts
Originally Posted By: smiller
Originally Posted By: TestPilot
That won't work. Feeding the ECU a constant voltage from the O2 sensor means the ECU will thing the AFR is correct no matter what it really is.

Since a constant voltage is illegal the ECU wouldn't think the AFR is correct, rather it would think that the O2 sensor is faulty and set a fault code and stay in open loop.

But either way, no, it wouldn't work. You maybe could build a circuit that spoofed the ECU by mimicking the correct O2 duty cycle.


That's right, a constant voltage looks like an error. Based on how the Motronic uses the O2 sensor, it can't be spoofed into a different target AFR. You really need an O2 sensor with a different switch point.

Nightrider.com has a patent on something that shifts the stock O2 sensors on Harleys but it won't work on a Beemer.

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#798320 - 08/28/12 04:42 PM Re: Wideband O2 Project [Re: roger 04 rt]
roger 04 rt Offline
Member

Registered: 11/27/11
Posts: 1814
Loc: Massachusetts
Dirtrider asked me the other day to take a test ride with fuel pressure set to 52 psi, Motronic reset and in Open Loop mode (Wideband O2 sensor unplugged). I got out yesterday and made the run.

My report is simple, the bike runs great--smooth, good power, very responsive to throttle from 2000 RPM or so on up, even in 4th gear. A lot like the Closed Loop test rides at 52 psi and Wideband O2 set to 13.8:1. It's not really a surprise to me that it ran well in Open Loop. But I want to point out one thing: because I had the Wideband O2 installed, I knew that my setting of the fuel pressure was producing the enrichment I was looking for. Without the Wideband O2, you can crank up the fuel pressure, but you can't say for sure where you are with the enrichment.

If you go back earlier in this thread to here: Open vs Closed Loop, notice how much flatter the Closed Loop curve looks and how much tighter the histogram distribution of AFRs is in the smaller plots.

The same thing happened yesterday when I rode at 52 psi, reset Motronic, Open Loop. The range of AFRs, rather than being tightly centered on 13.8:1 where mostly around 14.3:1 and 13.3:1 (the two horizontal dashed lines in the plot below). My educated guess is that this is how the Motronic tries keep the Catalytic converter running even if the O2 sensor is dead. Normally in Closed Loop, with a stock sensor, the Motronic runs fueling a few percent above and below 14.7:1. (Snooze alert: The reason for going to the lean side of 14.7 is to allow Oxygen to recharge the Cerium in the three way converter.) So now, Open Loop the Motronic makes big moves in the fueling, still hoping to create a lean-of-14.7/rich-of-14.7 scenario. This way too rich/way to lean is a sort of limp-home-mode. (It's noteworthy that this will be how many PowerCommander and Techlusion curves would look if anyone plotted them.) I think it is very likely that this causes more fuel consumption than the Closed Loop case.

So here is the Open Loop 52 psi plot with all its "wildness".




My favorite configuration remains:
LC-1 set to 13.8:1 with Fuel Pressure boosted to 52 psi (for E10 fuel).


Edited by roger 04 rt (08/28/12 04:43 PM)

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