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Old 11-26-2010, 04:45 PM  
johnjen
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Joined: Nov 2001
Location: Seattle
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Quote:
Originally Posted by Poolside
When I posted that data acquisition picture, the picture with the stuff on the tank, I didn't want you guys to think that was how complicated it is. That is the development and research setup I use to figure out all of this stuff.

You guys are right though, it isn't pistons and cams. You can go ahead and make those mechanical improvements. But without making changes to how the ECU delivers fuel and spark, the drivability issues will remain, and in many cases they get worse.

At this time there's four products in the works. Following posts are an explanation of the first two products, since they are close to being finished.

I'm sure most of you have a basic understanding of how EFI works. The ECU reads the sensors, air temp and oil temp for example, looks at the motor RPM, checks how far the throttle is open, and injects the right amount of fuel.

This is important:
The air temperature controls the 'open loop fuel mixture'.
The oil temperature controls the 'accelerator pump' feature.

"What do you mean by open loop fuel mixture?"
Here's what I mean. The fuel injection computer reads the air temperature and air pressure, and computes the 'weight' of the air. Then, based on the RPM and how far the throttle is open, it computes how much air is going into the motor. Finally, it squirts the right 'weight' of fuel into the motor to make the right air fuel ratio. For example, the familiar 14.7:1 by weight ratio.

"What do you mean by 'accelerator pump' feature?"
Here's what I mean. I'm pretty sure you understand that Electronic Fuel Injection systems do not have a mechanical accelerator pump like a carburetor. But, EFI does have the 'electronic equivalent' of an accelerator pump.

This bears repeating.
The air temperature controls the open loop fuel mixture.
The oil temperature controls the 'accelerator pump' feature.
Let me add that Poolside has a REALLY through understanding of how EFI systems operate. This reaches all the way down into the specific functional and mathematical algorithms that are used for the various portions of the EFI ‘states of operation’ themselves. Which means that depending upon in which ‘operational state' the engine is running, certain variables become important and thus/can be/are externally modifiable without having to re-write the algorithm itself. This is a decidedly GOOD thing for all of us because it means we only have to fuss with certain knobs to get the desired effects in a particular state of engine operation.

It should also be noted that while we use the term ‘operational state’ we do so in order to help describe how our modifications ‘plug into’ certain ‘operational states’ to affect those specific responses from the engine. These terms and our descriptions of them don’t really exist within the EFI nomenclature and are meant to help understand, in a simplified way, what is going on and what we can do to modify the engine's response.

This effort was hinted at years ago in a thread that both of us participated in where I asked for more details concerning the operational parameters. My quest was outlined in post #7 of this thread;

http://www.advrider.com/forums/showt...osition+sensor

We have come a long way since that thread was started and the desire to come to terms with ALL of that info has been greatly simplified, such that we have come up with ‘work arounds’ to solve or fix the inherent weaknesses that are apparent in the operation of our engines.

Thus far we have identified 5 states that we can modify to our (as in, us riders) benefit.
And we can specifically target the EFI's normal response to these 5 states and reap the benefits of a much 'healthier' running engine.

These 5 particular states are all 'tweakable' by particular adjustments to the sensor inputs to the EFI or by easily overriding certain programmed logical decisions made by the EFI. In either case we greatly improve the engines response from changes made by the throttle and other normal running conditions.

These 5 states are…
1. Steady state operation. (no change to the throttle input to the EFI)
2. Increasing the throttle angle. (as in acceleration)
3. Decreasing the throttle angle. (as in decelerating)
4. Starting the engine.
5. Idling the engine.


By themselves each of these modifications are significant and not only noticeable but welcome improvements.

But when used together the results are wonderful. The engine responds to it's full potential regardless of any and all other mechanical modifications, such as pipes, cams, pistons, intake mods, etc., simply because the programmed limitations inherently built into the EFI have been ameliorated.

And it should be noted that the results of our EFI modifications do in fact interact with each other. And indeed we must design each modification to interact with the other(s), or the results can be as bad or even worse than not adding them in the first place.

In short each of our mods can't just simply work by themselves but they also must work interactively with all the rest of them. And as more modifications are added the more complex/important the interactions become.

In addition to all of this, is the need to keep the kits themselves easy to install, easy enough for anyone capable of performing routine maintenance to handle.

AND we are still researching what other areas of engine improvements are possible.


JJ
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