Amesim Six Cylinder Crankshaft Simulation

Experimenter
Experimenter

Hello guys,

I am trying to build a six cylinder crankshaft arrangement by following the demo library present in the PowerTrain module(Engine Crankshaft.ame). I used the same properties that was show in the four cylinder crankshaft arrangment example. I have got the six cylinder pressure timming graphs from my professor.  This is how the complete model looks like.

Crankshaft_Model.JPG

The output from the crankshaft angle sensor didn't make any sense to me.  I can pretty much understand from the angle sensor plot that there is negative torque and is constant for some time. Which pretty much says that torque is not transferred from other cylinders. This is how my output looks like:

Angle_sensor_output.JPG

In reality the above output should be linear.

 

I am doing mistake somewhere in the process. Which I tried to debug for 2 weeks. I wasn't able to. I am amateur to this crankshaft subject. Kindly, waiting on your suggestion to improve this model and my understanding.

 

Thanks for your time,

Meme.

 

P.S

Sorry for the picture clarity. And, I have given respective Pressure - Timmings graphs for respective cylinders.

 

3 REPLIES 3

Re: Amesim Six Cylinder Crankshaft Simulation

Siemens Phenom Siemens Phenom
Siemens Phenom

Hi @Meme,

the model structure looks good.

A couple of things to check:

- maybe one or several cylinders are not properly initialized, check their displacement in time to make sure they are as they should be.

- not sure if the ignition order is actually as you expect, the attached plot shows:1 ,2, 3, 4, 5, 6 when the firing order on the sketch is 1,5,3,6,2,4...

- it could also be due to the load torque which is controlled by the PID loop on the top right corner of your model. It's trying to achieve a specified speed profile, plot variables around that loop: objective speed, current speed, load torque.

 

Re: Amesim Six Cylinder Crankshaft Simulation

Experimenter
Experimenter

You were right on the ignition order part. I have changed it and have tested the model. Unfortunately, no results yet. I figured out that, having the specific properties for all the cylinders and stiffness is very neccessary. This is causing some ill-logical results. The properties I have used for all the cylinders and stiffness are taken from the demo model (Enginecrankshaft.ame) in transmission library. Looks like I need to make some calls to get these properties. This is gonna be tiresome. I'll keep you posted.

 

Thanks for your reply,

Meme

Re: Amesim Six Cylinder Crankshaft Simulation

Experimenter
Experimenter

The problem is I didn't mention crankangle throw in the parameters which affected the overall outcome of the solution. Thansk @Emmanuel_D for helping me out.

 

Technical Explanation:

The crank throw angle is set to zero for all the cylinder. This means that all the cranks have same starting position. Even if you set up the in cyliner pressure offset, the engine won't work well. Thanks to emmanuel for mentioning this point.

six_cylinder_piston_ intial_position.jpg

Look how the initial position of the pistons are arranged. In my case it was set to zero.