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[whittlebeast]

Here is an example of a scatter graph that can reverse engineer the timing table that the motor is running.  I flipped the RPM upside-down to make it easier to see the timing table that is generating the reported timing at the data cable.

RPM is in the vertical scale and MAP is in the horizontal scale.  Color represents timing at each RPM and MAP.



Any questions?.....

Andy

[whittlebeast]

Here is a sample trace where you can see the lambda target on the left and the average lambda that I actually get at the o2 sensor.  The data matches fairly close.  Note that this is a bike in open loop that was tuned on a TPS based tuning.

Notice that the RPM has been flipped compared to the previous post.  MAP is still on the horizontal axis.



Any questions?

Andy

[FLTRI]

Wow! Andy, you're right, it jumps right out at you doesn't it?
Bob

[whittlebeast]

We are only just scratching the surface at this point.  This motor is fairly well tuned so tuning issues aren't showing up in these plots.

Keep reading along.....  We will get to that stuff.

Andy

[whittlebeast]

Here is a motor displayed in Speed Density on the left (RPM and MAP) and on the right in Alpha-N (RPM and Throttle position)



In color is the number of hits or the number of times the motor visited this part of the map.  Points displayed  in red imply that is where the motor spends most of it's time on a normal street ride.

Andy

[North Georgia Hawg]

Hey Ken

Look forward to meeting you in Maggie Valley!

 

SBB

You too, Chip! It will be a GOOD TIME! 

There are a lot of people with whom I have been talking the last two years on this site who I have never met. I should have gone last year. Better late than never! 

Ken

[whittlebeast]

Here is the same view but with the color representing AFR



If you tag in any one spot, the software will give the matching point on the other plot.  This feature will be a big deal later when we get into tune trouble shooting.

Andy

[whittlebeast]

Here is a motor that was driven to allow the Long Term Fuel Trims to take a set.  Then we turned off the Closed Loop and rode the bike.  It is interesting how Harley elected to have very distinct boxes to hold the same value.  I seldom see this on most EFI systems.



Have fun tuning

Andy

[whittlebeast]

The next thing we will get into is basic calculations and filters.  This can be used to see all sorts of things.  This is what is commonly known as a gear chart in road racing.  It is Vehicle Speed plotted vs RPM.  In color is displaying gear or gear ratio in these plots.  Filters are applied to hide the data during shifts.





Filters in MLVHD are simply formulas that you design to throw out data that you do not want displayed.  In this case, I simply threw out all data when Acceleration Enrichment or Decel Enleanment was active.  I used the formula

[Acel Enr]>0 or [Decl Enl]>0 and then turned the filter on for the right plots.

For gear ratio, I used the formula

[RPM]/[VSS]

Have fun tuning

Andy

[whittlebeast]

Here is a formula that is a little more interesting that we call TpsThrottling.  The formula is defined as

10*sqrt([TP])

What this formula does is take the square root of the throttle angle and multiplies that times 10.  This is loosely the percent of available torque being produced by the motor at any moment in time.  Here is MAP vs RPM and TpsThrottling on the right compared Throttle position on the left.



Have fun tuning

Andy

[whittlebeast]

Wile talking to a "Harley tuner" today, the subject of Harley fuel balance came up.  He mentioned that the Y manifold causes all sorts of strange things.  I told him that is really east to see in both terms of MAP vs RPM and TP ve RPM.  I create the formula.

100*([PulseWidthFr]-1)/(([PulseWidthFront]-1)+([PulseWidthRr]-1))

Note: Your field names will change depending what logger you are using.  The -1 is used to account for the about 1ms dead time for the injectors.

Here is the plot you get....



Notice that in overrun, the balance is a mess.  In the midrange, about 55% of the fuel comes out of the front injector.  At WOT the balance is real close to 50-50.

This happens to be a Sporty.  The results tend to be way closer to even on the BT motors.

Way cool.

Andy

[whittlebeast]

A couple of more shots showing the o2s doing there thing in both voltage and how they have caused the ECU to figure out how to lean on the stock fuel tables.

In this plot, we see the area of the tune where the o2s are "switching"



In this plot we see the long term fuel trims as defined by the formula

100*[VE New Front]/[VE]



This has everything to do with how autotune logic works.  Way cool stuff

Andy

[whittlebeast]

Acceleration enrichment and DE.  I will demonstrate how to test for it later.



Andy

[joe_lyons50023]

Thank you for posting up this information andy

[whittlebeast]

To see AE (and DE) you have to get your head around how Speed Density works at it's simplest form.  The two most significant constantly changing factors that drives the amount of air pumping thru a motor is RPM and MAP (Manifold Absolute Pressure).   If you double the RPM, the air flow will generally double.  If you double the pressure in the intake, you double the air molecules in every gulp of air the motor takes.

Bottom line is you can multiply MAP x RPM and you wind up with a mass of air per time.

Now think of Duty Cycle on a fuel injector.  By definition it is a percentage of time that the injector is spraying at full flow, sort of...   It gets a little messy when you consider injector opening time when you consider that at 6000 RPM there is twice as many opening times in 1 min compared to 3000 RPM but we can account for that later if you want.  Lets keep things simple for now.

Now let's bring this all back to scatter graphs....

In this plot we are looking at a totally stock Sportster running almost entirely riding in closed loop.  So the AFR is real close to 14.7, in theory.  We will get to this in a later post.  Suffice it to say,  If you double the air getting into the motor, you need to double the fuel to hold a single AFR.



You can see that when you plot MAPxRPM/100 on one axis and DuyyCycle on the other axis, you get a straight line.  As it turns out the Sporty develops two lines.  Notice that One of the lines a distinctly different color than the other.  Looking at the scale for the color of the line indicates that the o2 are running lean on the lower line and butt fat on the upper line.  As it turns out if the ECU would have delivered the PW that is the tweener of the two lines and the resulting AFR would have been a near dead nuts 14.7 AFR.

Next time I will get into what you are seeing on the right plot.  Hint, Accel Enrichment jumps out at you as static in this view.

Have fun tuning.

Andy