Varying the Intake Valve closing (IVC) in CONVERGE
 

Hi everyone.

My name is Syaqir and I'm a final year engineering student from UNSW Sydney. Currently doing a study on how implementing the Miller Cycle along with the addition of superchargers/turbochargers can affect the combustion and NOx emissions of a diesel-hydrogen compression ignition engine.

The relevant base valve timing is included in this thread as an attachment for everyone's reference.

My question is:
1) How do I change the Intake Valve profile so that the IVO stays the same while I retard the IVC? Do I manually insert the values myself or is there another way to do that? If I have to manually do it, I only have access to the following data: IVO ca, maximum lift and IVC ca. How do I generate the other lift values in between the data to generate the bell-shaped curve as shown in the attachments?

2) From what I can recall, some intake charge will be pushed back out of the cylinder resulting in loss of pressure when implementing the Miller Cycle and from review, a possible solution would be to utilise turbochargers/superchargers. These if I'm not mistaken means that I need to increase the pressure to simulate the turbochargers/superchargers. Which pressure exactly do I have to increase? I have a strong feeling that it's the intake/inflow pressure but wouldn't hurt to ask the forum for confirmation

Hope to hear from anyone soon. It would really help me for this study. Thanks in advance everyone!

Regards,
Syaqir

Hi,


do you have a GT-Power model to generate required input like this?
There you could modify the valve lift and get new intake port pressures as well.


If not, i would modify the valve lift in excel. You could then do a coarse simulation (gridscale set to -2) to estimate the trapped mass and increase intake pressure according to procentual change.

Thank you Tobias so much for your answer and suggestion in approaching this. I will give it a try and see what the results are like.