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[Webby the Bear]

Bang in TB cheers for explaining that.

It also means that if my car had a performance issue when flooring it (it doesn't, I'm just talking hypothetically) I could rule out miss daisy vs nutter scenario. . . Assuming it was serviced regularly, breathers clean, and it got the odd Italian tune up

[Andy H]

Just a thought - so don't shoot me

The ECU is programmed with a complex set of 3D maps. The maps should be just about perfect across the whole range of revs and load but due to Euro noise and emissions regulations the manufactures have (allegedly) tweaked selected areas of the maps to pass. (probably the areas where most power is produced)

Miss Daisy drives sedately, the ECU never strays into the tweaked areas of the map. The ECU learns nothing and the fuel trims don't change.

The next person who drives goes for an Italian tune up. The ECU uses the sub-optimal parts of the 3D maps, the ECU learns and changes the fuel trims to compensate. The engine now runs better in those parts of the maps

Just a thought...........

[Phil L]

Ok, some facts

1) The engine ECU does not learn your driving style
2) The engine ECU can not be reset by removing the battery

Right, now we have that straight lol, the ECU that does learn your driving style is the autobox......

Interesting, thanks

[jimbo125]

Complex and confusing at times, so fuel trims are the variable here then?

[Marks DTM Calib]

Just a thought - so don't shoot me

The ECU is programmed with a complex set of 3D maps. The maps should be just about perfect across the whole range of revs and load but due to Euro noise and emissions regulations the manufactures have (allegedly) tweaked selected areas of the maps to pass. (probably the areas where most power is produced)

Miss Daisy drives sedately, the ECU never strays into the tweaked areas of the map. The ECU learns nothing and the fuel trims don't change.

The next person who drives goes for an Italian tune up. The ECU uses the sub-optimal parts of the 3D maps, the ECU learns and changes the fuel trims to compensate. The engine now runs better in those parts of the maps

Just a thought...........

Sadly not though as the map is not revised, only a long term and short term fuel trim on a per bank basis e.g. a single correction value for the full map.

Furthermore, on a standard engine running well, the fuel trims are pretty much zero.

So no, the driving style wont impact the map or engine running. 

[Marks DTM Calib]

Complex and confusing at times, so fuel trims are the variable here then?

Yes and they are exactly as the name describes, a trim, e.g. a small correction value to ensure optimum fuel combustion and hence minimum emissions.

Consider how the engine management system works, in simple terms

1) A demand is applied by the right foot
2) The ECU weighs the air coming in (via the MAF - Mass Air Flow sensor)
3) The ECU looks at engine revs
4) The ECU considers the throttle position and, the rate of change of throttle position (d'throttle/dt)
5) The ECU looks up in the engine map the required mass of fuel required to properly combust the mass of air (so its like making a cake!)
6) The ECU injects the required mass of fuel (considering air temp for correction also, but this is a minimal change)
7) The ECU then looks at the O2 sensor to see how well it did.

Its at stage 7 that the correction values are created, and used to modify the mass of fuel injected.

Have a read in the guides section as I did a short write up many years ago on the cycling weak/rich of the mixture for optimal mixture control.

This is also why raising fuel rail pressure and various other mods don't work, as the trim value dials them out!

[Diamond Black Geezer]

[Field Marshal Dr. Opti]

So. I decided to do a little experiment.

For a couple of weeks I'd drive like miss daisy and drive real slow. After this period I'd take the car out and give it a thrashing and see how the power was delivered. After this time it definitely felt like it was a bit lethargic.

For the next couple of weeks I thrashed the car literally revving the nuts off it and flooring it everywhere  I then after the same time did the same experiment and it certainly felt more responsive in the same conditions.

Now I like to rely on facts and evidence and 'feelings' are a bit untangle able so is this placebo or is this a real case of seeing the learning ECU in action?

My next question is if this learning ECU stuff is correct how does it learn the drivers style?

Placebo?

[The Sheriff]

Complex and confusing at times, so fuel trims are the variable here then?

Yes and they are exactly as the name describes, a trim, e.g. a small correction value to ensure optimum fuel combustion and hence minimum emissions.

Consider how the engine management system works, in simple terms

1) A demand is applied by the right foot
2) The ECU weighs the air coming in (via the MAF - Mass Air Flow sensor)
3) The ECU looks at engine revs
4) The ECU considers the throttle position and, the rate of change of throttle position (d'throttle/dt)
5) The ECU looks up in the engine map the required mass of fuel required to properly combust the mass of air (so its like making a cake!)
6) The ECU injects the required mass of fuel (considering air temp for correction also, but this is a minimal change)
7) The ECU then looks at the O2 sensor to see how well it did.

Its at stage 7 that the correction values are created, and used to modify the mass of fuel injected.

Have a read in the guides section as I did a short write up many years ago on the cycling weak/rich of the mixture for optimal mixture control.

This is also why raising fuel rail pressure and various other mods don't work, as the trim value dials them out!

Yep. Old school thinking for old school engines.

[The Sheriff]

So. I decided to do a little experiment.

For a couple of weeks I'd drive like miss daisy and drive real slow. After this period I'd take the car out and give it a thrashing and see how the power was delivered. After this time it definitely felt like it was a bit lethargic.

For the next couple of weeks I thrashed the car literally revving the nuts off it and flooring it everywhere  I then after the same time did the same experiment and it certainly felt more responsive in the same conditions.

Now I like to rely on facts and evidence and 'feelings' are a bit untangle able so is this placebo or is this a real case of seeing the learning ECU in action?

My next question is if this learning ECU stuff is correct how does it learn the drivers style?

Placebo?

No. It was his omega.

[Field Marshal Dr. Opti]

So. I decided to do a little experiment.

For a couple of weeks I'd drive like miss daisy and drive real slow. After this period I'd take the car out and give it a thrashing and see how the power was delivered. After this time it definitely felt like it was a bit lethargic.

For the next couple of weeks I thrashed the car literally revving the nuts off it and flooring it everywhere  I then after the same time did the same experiment and it certainly felt more responsive in the same conditions.

Now I like to rely on facts and evidence and 'feelings' are a bit untangle able so is this placebo or is this a real case of seeing the learning ECU in action?

My next question is if this learning ECU stuff is correct how does it learn the drivers style?

Placebo?

No. It was his omega.

Hmm.....the new Vauxhall Placebo. That has a certain ring to it.

It's crap but everyone tells you it's a great car. After a while you begin to believe it.

[The Sheriff]

So. I decided to do a little experiment.

For a couple of weeks I'd drive like miss daisy and drive real slow. After this period I'd take the car out and give it a thrashing and see how the power was delivered. After this time it definitely felt like it was a bit lethargic.

For the next couple of weeks I thrashed the car literally revving the nuts off it and flooring it everywhere  I then after the same time did the same experiment and it certainly felt more responsive in the same conditions.

Now I like to rely on facts and evidence and 'feelings' are a bit untangle able so is this placebo or is this a real case of seeing the learning ECU in action?

My next question is if this learning ECU stuff is correct how does it learn the drivers style?

Placebo?

No. It was his omega.

Hmm.....the new Vauxhall Placebo. That has a certain ring to it.

It's crap but everyone tells you it's a great car. After a while you begin to believe it.

[Diamond Black Geezer]

 


It's called the Ampera