Boost control PID

[chris72]

HI
Hopefully someone can offer advice on this

i currently use a MAC PWM solenoid to control the upper area of the wastegate,
the EMU currently controls this with a DC / RPM table with a maximum boost being reached at 80% (220 KPA). This works very well but the bike is slow to build boost after a gearchange as i have the solenoid at 80 %.
Engine rpm is 10800 before the shift and 9500 after so this should not be a limiting factor.
would i be better switching to the target boost table with PID contol in this way i can request 220 KPA and the solenoid should react accordingly and try to achieve target regardless of engine speed ? and can anyone suggest starting values for the PID loop.
or is there a better way ?



thanks

[Jadzwin]

You can try use DC error correction instead of PID.
Just add some %DC if the boost is below the target. However you need to make BOOST target tables.

Do you change gears with the full throttle ?

[chris72]

Ok
at the moment there are no values in the boost target tables, what i want the engine to do is get as near as possible to 220 KPA of boost from 80 % throttle at lower throttle positions i will decrease target boost
so is this as simple as just putting 220 KPA in all of the cells above 80 %
i also use the VSS table to control how much boost is developed the turbo starts to develop boost from around 5000 rpm and pulls really well

all gear changes are at full throttle with 85 mS flatshift time

thanks

[chris72]

I have made new boost tables for the bike together with DC correction, do these values look sensible ?
I will use VSS scaling to reduce boost in the lower gears.

[chris72]

New maps loaded to bike will test this weekend

[Jadzwin]

Please let us know if it helps.

[chris72]

I may be sensible and lower the boost target for the first run

[Jadzwin]

Hi!

There is idea how to solve your problem, but you need to use Gear Cut function of EMU for gear shift.
We can add option to set fixed DC of boost control solenoid when gear cut activated.
You will just define how long the fixed DC must be activated after gear cut (in ms)

[chris72]

Hi
The boost control was much better ( 9.135 @ 165 MPH) but still dropping off during the flat shift. ( i will attacl graph later)
If you could add the extra fields to the gear cut function that would be great.
Also a big thank you for the engine protection function i had a failed thermostat and water temp of 110 degrees EMU cut the rpm to 6000 and no damage

[Jadzwin]

I can't imagine 9.135 on the bike. It is insane

[chris72]

New boost log with error correction activated



Boost target is 220 KPA max achieved = 215 KPA this is ok i may increase error correction table slightly next time out

This is much better than before boost is dropped for around 0.5 second previous time was just over 1 second ( time for flat shift and mechanical delays is around 150 mS) but can we make it even better

9.135 on a bike is ok 8.5 would be better

[Jadzwin]

I think that fixed DC after gear shift should make the job.
Or ALS
Do you keep full throtthe during gear change ?

[chris72]

Hi
Yes full throttle for all gearshifts

On another topic, while the bike is held on launch control 6500 RPM there is a lot of banging from the exhaust, would increasing the amount of ignition retard reduce this ? at the moment i dont remove any timing so the EMU will select advance for 100% throttle 6500 RPM is this correct ?

[Jan32]

Normally it is like this, early ignition Angle reduce the banging and the flames. And an late ignition angle gives more banging and flames. So if you use the option of retard it should be more. What is your ignition angle now at the launch? Maybe you can give a bit more ingnition angle.

[chris72]

Hi Jan

ignition angle at 6500 RPM will be between 30 and 32.5 degrees BTDC at the moment i do not use the retard option

thanks
chris

[Jan32]

Hmm that is early enough. So if you use the retard option it will be more banging.

[chris72]

Thanks Jan

ignition angle on this engine is normally between 27 and 35 degrees once above 1500 RPM, the ignition map is a direct copy of the manufatures table.
I think i will try ear plugs instead

thanks
chris