Config switch / Dual table

[JRD McLAREN]

I'm saw something about this on slack ...
So can we summarize it on this topic ..?

(I have no idea, what we can do on TS side, or rusefi side)

We must trigger it - any analog input will be used

Some scenarios "why we need this"
- different algorithm - speed density, alpha-n, ....
- different fuel type - gasoline, methanol ... =different VE, IGN, Boost table
- different fuel quality
- different BOOOOOOOST ... (or overBOOST..... or NO BOOST )
- different engine parameters = more torque on high / low rpm, diff CAMs position ... .

What we need the same on both confs
- basic trigger setup (engine setup)
- basic sensor setup, analog inputs, etc.
- injector and ignition outputs
- ETB setup

Please add / complete my list ...

[Dron_Gus]

I would also suggest to have separate limp mode VE alpha-n table.

[AndreyB]

Best discussion so far at https://github.com/rusefi/rusefi/issues/3114

At the moment we have not yet agreed on a good "why"

[mck1117]

Yes, this is certainly in the plan. Probably to be implemented via lua, since it requires huge flexibility to actually be useful.

[JRD McLAREN]

Code: Select all

Pavel says he needs two maps:

1    eco mode, up to 4k highway driving
2   sport mode

NA engines

This is the bad point of view ......
..

[AndreyB]

This is the bad point of view ......
..

With zero arguments or explanation this is a pointless comment. Please invest into being understood.

[JRD McLAREN]

CAUSE ...
you don't need separate VE table for "economy" mode .. or "power mode" ..
It is not about "what driver wont" ...
It is about "WHAT ENGINE NEED" ...

At 4kRPM and 35%TPS and 90kPa MAP engine need 6.3ms Inj time ..
and ...
At 4kRPM and 35%TPS but 80kPa MAP engine need 5.2ms Inj time ....

..it is still the same engine, if you drive it on highway or on track ... (or DRAG race)

and also you don't need different AFR table .. (for this "scenario")
at 90-100kPa you have set target AFR to 13.6 ... (at 4kRPM)
at 70-80kPa you have set AFR to 14.5 ..
at 50-70kPa you have 14.7
below 50 have 15.2

...
So, "WANTED" POWER MODE / ECONOMY MODE TABLES ... does not exist ...
(it can be "any region" in one / basic table)

[JRD McLAREN]

Wanted Power Mode / Economy Mode table is not the reason to make "Config switch / Dual table config"

[mk e]

CAUSE ...
you don't need separate VE table for "economy" mode .. or "power mode" ..
It is not about "what driver wont" ...
It is about "WHAT ENGINE NEED" ...

At 4kRPM and 35%TPS and 90kPa MAP engine need 6.3ms Inj time ..
and ...
At 4kRPM and 35%TPS but 80kPa MAP engine need 5.2ms Inj time ....

..it is still the same engine, if you drive it on highway or on track ... (or DRAG race)

and also you don't need different AFR table .. (for this "scenario")
at 90-100kPa you have set target AFR to 13.6 ... (at 4kRPM)
at 70-80kPa you have set AFR to 14.5 ..
at 50-70kPa you have 14.7
below 50 have 15.2

...
So, "WANTED" POWER MODE / ECONOMY MODE TABLES ... does not exist ...

You can run a lean burn or high EGR on the street to improve fuel milage then turn it off at the track....I've seen that done.

More common is something changes street to track like you have an engine that is on the knock line and +fuel&-timing on pump gas to make it happy but at the track you run C16 racer gas which needs more fuel and will tolerate optimal timing. The other maybe more common use is changing boost level. A lot of high boost applications detune for the street to make the car more drivable or run on pump gas. At the track the boost goes up, the race gas goes in and it needs a different tune.

A signal input that selects that selects matched fuel/spark/boost is the common setup. Personally, that has always seemed like a blow up the engine switch so I physically load new maps when I switch fuel as it seems safer...but i guess I could still forget.

Another application is "valet key" or "safe mode" so a dangerous high hp engine is restricted. I've been giving this some thought with a now 14 yo boy in the house. I have DBW so this would likely retune the throttle...not sure.....

[JRD McLAREN]

you mean EGT ... right ...

mke read my first post .. please ...

If you run WOT, you need rich mixture, due to EGT must be in safe zone ... (750-800stC)
and it's the same on track, street, etc ...

(Modern cars run 14.7 full time, no boost, boost. After EGT grow up, then ecu rich the mixture)
(many people hit WOT 2 -3 times, on "long free" street in the city, for 5 to 10 sec. )
(and EGT not grow enough to ECU must rich mixture more then 14.0)

If you drive to highway, on speed limit, you are not in "full load" ...

Knock limit is few deg. after optimal pre-ignition value ... (bTDC)..
it will be still safe, if you run on 98oct fuel, and sometimes something worst - like 95 fuel ...
(knock detection handle this ... ? )

[Dron_Gus]

1. I want to have safe map and experimental map. I'd like to switch to safe map if I feel something going wrong. Without attaching TS.
2. As I said before, we do not have 98 gas on each gas station. In some locations you can only get 92. Russian grade 92, that is about 87 RON? People here prefer to have two tunes. For good fuel and for some other.
3. Some people use water injection. Ignition map and AFR map is quite different when water tank is empty.

[mk e]

you mean EGT ... right ...

No, EGR as in Exhaust Gas Recirculation. A gasoline engine running at partials throttle is pretty inefficient because its doing work to pull a vacuum in the manifold, which then is effectively decreasing the compression ration in the cylinder....so a double hit. Either lean burn or ERG strategy will allow the throttle to be opened more and improve efficiency. EGR is preferred for emissions as lean burn creates more NOx but lean burn can be done on any engine with just tuning changes.

At least 1 guy I know routinely uses the EGR valve to control detonation around peak torque because reducing cylinder pressure a little with ERG often yields a higher output then doing it with reduced timed. Again these are engines that are really past what is safe on pump gas especial around the torque peak. I have used that same thinking on a DBW setup to simply not allow full throttle near torque peak rpm....a feature I disable when there is adequate octane fuel available.

Another guy I know is running an AFR of 32:1 on his 66 Pontiac on the highway and getting over 27pmg....in a big old pontiac. The factories were playing with this in the early 70s when the gas crisis hit but the work ended when emissions rules hit. Its very effective though is improving fuel mileage is your goal.

Other the other side of this is most race fuel want to be run richer than most pump gas wants to be run....usually around 10-15% richer and timing usually also needs to change a bit. I did a few dyno shootouts years ago and was running 9% nitro because 10% would fail tech in the gas I was using....I'm trying to remember the jetting change, it was a lot, 30%? but its track day changes like these that require track day tuning.

I personally don't run knock detection because the normal noise based systems struggle to detect knock early enough to be helpful on engines with a lot of background noise from solid lifters and forged piston which are the engines I'm generally working on, so it just isn't helpful. I also don't run closed loop at anything above highway engine loads because I really don't want the ECU undoing anything I did on purpose....there is a fine line between a streetable engine and a race only engine and a good ECU makes the line pretty blurry

To your point, most people don't need multiple maps, but.....