als rocket system

[AbatelliCristian]

I hope this winter I have possibility of testing rocket ALS system.
I'm not expert with that system, but I think is good insert the strategy.


1 - speed turbocharger is indispenble for limits
2 - egt limits
.....
????


do you have idea?

[tpsretard2]

Do you mean an actual rocket, or just an egr based als.
For a rocket based system You will need post and pre turbo egt with the ability to shut down the als on ether. You will also need to have a different form of boost control than the ms3 has. You will need a turbo speed based control strategy.

[AbatelliCristian]

you think the system is always on?

Example, when tps is 100%, the rocket is active? in this case the flow of compressor for max power is critical.....
I think when tps is 100%, the system is of and the boost controll is standard.
When tps is partial is important the rpm turbocharger for limit controll.

Is correct my idea?

[tpsretard2]

An ALS system, be it a traditional jack throttle als, a hybrid EGR system, or one using a combustor (rocket) is active n part throttle of off throttle situations.

This is why you need boot control based on turbo shaft speed, Pre turbo pressure is also usfull but nessesary really.

With regards to boost control, shaft speed control is the absolute more relable and stable way of controlling boost. If the ecu supports this, there is no reason to swap between shaft speed and manifold pressure control tratigies based on throttle angle.

[muythaibxr]

tpsretard2: The shaft speed required to target a particular boost changes with both throttle position and RPM... Why target that to get a particular boost when you can actually target boost directly?

I can see the need to limit shaft RPM in some cases but not to control boost entirely on shaft rpm.

[tpsretard2]

We use a map of tps vs rpm and have shaft speed values in there.

There is nothing wrong with swaping to a target boost after the ALS parameters shut it off and goes to a normal map. But with ether fully closed or partially closed throttle, an egr or rocket based ALS system will over spin the turbo very quickly.

We run about 68psi closed throttle on the line at 1800rpm on a 2L engine with a yurbo about the size of a gt3071r. It would just be impossible to control with only a target boost.

Also if you are using a yurbo that is a little smaller than the engine needs you can hit the terminal speed of a turbo before your max boost point in the upper rpm range of the engine. For the road this is not a problem as the turbo will not be over spun for long enough times to cuase damage. However on a race/rally car this can happen easily.

[muythaibxr]

OK, we'll at least look into ways of limiting turbo speed with ALS. I'll talk to James about it.

[AbatelliCristian]

very thanks guys