VNT closed loop boost control
Posted: Tue Aug 15, 2023 12:43 amEvening everyone,
Excuse the lack of knowledge, this is all very new to me. Just a young fella having a go.
Bit of context. 1HDFT engine (6 cyl diesel) VE mechanical pump, I’m running a VNT Turbo charger actuated by a garret DC stepper motor PWM ( 47 pound by 2000rpm@1.5 lambda
)
Few questions - first of all - I run a M84 ECU and a C127 dash, I’d like to display my boost control ( aux output) duty on the dash, so I can continue building on my normal position table for closed loop, I’m currently running boost control open loop. Is this possible? How would I go about this?
Which leads me to my second question - I’ve built a open loop duty table for boost control (tps x rpm) and it works very well, I’m very happy with it, I was hoping to use this table as a normal position table but obviously it isn’t boost pressure target over rpm so it does not work. I’ve tried putting the open loop table into the aux output table, but it doesn’t seem to make any difference in closed loop, like the table is inactive. Am I missing something or is this the case?
3rd question - rpm signal fighting a bit of a dirty signal above 3000 rpm, it’s not enough to throw out the boost control but it jumps around on the C127 enough to annoy me, my rpm set up is multi tooth, 18 teeth per rev. But my only tacho source is from my VE mechanical injection pump, which to one revolution on the crank is 18.5 teeth. (23 tooth gear off a 37 tooth gear that runs half crank speed) is the extra half a tooth per rev enough to cause this issue? Is there a better way to set this up? I have no other tacho sources available on the engine. Failing this I will pull the pump off and grind teeth down to suit even teeth, or will make a bracket and pick up on the balancer.
Thank you very much in advance
Excuse the lack of knowledge, this is all very new to me. Just a young fella having a go.
Bit of context. 1HDFT engine (6 cyl diesel) VE mechanical pump, I’m running a VNT Turbo charger actuated by a garret DC stepper motor PWM ( 47 pound by 2000rpm@1.5 lambda
)Few questions - first of all - I run a M84 ECU and a C127 dash, I’d like to display my boost control ( aux output) duty on the dash, so I can continue building on my normal position table for closed loop, I’m currently running boost control open loop. Is this possible? How would I go about this?
Which leads me to my second question - I’ve built a open loop duty table for boost control (tps x rpm) and it works very well, I’m very happy with it, I was hoping to use this table as a normal position table but obviously it isn’t boost pressure target over rpm so it does not work. I’ve tried putting the open loop table into the aux output table, but it doesn’t seem to make any difference in closed loop, like the table is inactive. Am I missing something or is this the case?
3rd question - rpm signal fighting a bit of a dirty signal above 3000 rpm, it’s not enough to throw out the boost control but it jumps around on the C127 enough to annoy me, my rpm set up is multi tooth, 18 teeth per rev. But my only tacho source is from my VE mechanical injection pump, which to one revolution on the crank is 18.5 teeth. (23 tooth gear off a 37 tooth gear that runs half crank speed) is the extra half a tooth per rev enough to cause this issue? Is there a better way to set this up? I have no other tacho sources available on the engine. Failing this I will pull the pump off and grind teeth down to suit even teeth, or will make a bracket and pick up on the balancer.
Thank you very much in advance