instant. consumption measurement

[sascha]

Hi Cail,

How do the options:
a) Trim Fuel E. on engine conditions
b) Trim Fuel E. by Lambda value
below vehicle setting actually work? One of both sets the instantanous co
nsuption (l/h) to zero when lambda goes up (to 2 - deceleration fuel cutoff) so far so good. But sometimes that just doesnt work or the instant. consumption does not correspond with the consumption in l/h and the current (unchanged) velocity - even for a quite long time.
Are the integration/ averaging intervals so different? How can I change them?

Regards,
Sascha

[cail]

Hi sascha,

Only a) sets instant consumption to zero. b) is just a correction coefficient - multiplier.

There is of course some discretion intervals for both of these. Normally, the status is read every 3 secs for Fuel Engine Conditions, and every 4 secs for lambda.

So in cases when your engine behaves faster that this, you'll see no "influence".

The parameters are not configurable for now, but I can introduce the changes.

BTW for Engine conditions sensor there is need for some more fixes. On some vehicles (mine f.e.) it also reports a fuel trim when I do a kickdown speedup. The reason I think is that engine trims and then starts again fuel injection in a very high rate to save it from overload - but for hobdrive that looks like for another 4 seconds there is no fuel consumed.
Because of this issue I don't use a) personally and still searching a way to workaround this problem.

[sascha]

I have observed similar strange things. The problem is that at the moment he does not recognize short coast load periods (p.e. turn right at an intersection without stopping or breaking)
He gets confused so that he can´t consider the subsequent acceleration phase properly (almost kick-down - to prevent the engine to go to enrichment)
But shouldn´t the lambda correction alon be sufficient to detect fuel cut-off at deceleration with gear?
Shure the average consuption is in the right ballpark but I am a bit concerned that some fine details are not captured correct. Hence I can not assess the consumption impact of my driving style variations properly. I would really appreciate if you woul keep us up to date, what you are testing or takeing into consideration for the next versions.


Regards,
Sascha

[sascha]

There is of course some discretion intervals for both of these. Normally, the status is read every 3 secs for Fuel Engine Conditions, and every 4 secs for lambda.

So in cases when your engine behaves faster that this, you'll see no "influence".

The parameters are not configurable for now, but I can introduce the changes.

if internally he reads the engine conditions every 3-4 seconds what was the reason to choos such al long interval? Computational power? Because I think my OBD/ car provides the most important values roughtly each second. Can I shange the intervall in one of the numerous files? Thanks a lot!

[cail]

But shouldn´t the lambda correction alon be sufficient to detect fuel cut-off at deceleration with gear?

I don't have lambda so I can't judge. Do you see that lambda value cuts down to Zero during fuel cut off? If so, of course that is an alternative.

if internally he reads the engine conditions every 3-4 seconds what was the reason to choos such al long interval? Computational power? Because I think my OBD/ car provides the most important values roughtly each second. Can I shange the intervall in one of the numerous files?

Keep in mind that hobdrive have to read quite a big set of sensors in parallel.
Normal performance is 3-4 sensor per second. And making Lambda/FuelStatus read by every second we seriously slowdown other parameters - speed, maf, rpm etc. And these are actually much more important for precise consumption calculation.

Think fuel cut/corrections takes no more that 1-2% of overall consumption numbers (with common driving habits of course). So it is more not about ride for the "precision" - these help more to understand the engine behaviour.

I'll try to introduce configuration for Lambda/FuelTrim read periods in next update.