My "generic engine" block seems to not care about the throttle input.

Hello everyone !

I here in order to get more and more knoledge about simulation with Simulink and the Simscape library.

My project now is to simulate an boat engine, the specificity of this engine is that it has to turn all the time at 1700 rpm, and when we want energy we link to it to a generator and then the electricity is distributed in all the boat.

But for now, I just want to simulate this engine, and I have some problems with this :

• First of all, I understand that the "generic engine" is like a car engine (the more you press the pedal, the more power you get), to compensate for this I just put in the speed vector a range of 5% of difference of 1700 rpm. Like this for all the load that I applied it will approximatively turn at 1700 rpm.
• Then for the dynamics section, I don't really understand how works the internal inertia but I put an initial speed of 1700 rpm (logic).
• I added the fuel consumption table.
• In order to just have the engine, I connected it to a rotational refference and an inertia block. I linked the solver to the link between the engine and to rotational refference.
• I added a constant as a throttle input, or a signal of 2395 element that change between 0.2 and 0.7.
• Finally I added scope for Power and Fuel Consumption.
• 

Unfortunetly when I launch the simulation I got 0 kW for Power and a very small constant value for the Fuel Consumption.

I also made a test with a "Rotational Electromechanical Converter" block and a current sensor. The only thing that I observed is that with a very high inertia the current start high and reduce to zero.

That's why I'm thinking that my throttle input have no influence on the engine. It is like the engine is not turned on.

If someone have any idea about a solution to my problem, I will be very grateful. (this is only the first step of my project)

Thanks in advance to anybody that awnser to this post ! :)

Answer 1

[J Chen]

The attached file contaons a running example. These are my suggestions:

1. It seems that some inertia need to be associated with the Generic Engine block either added internally or connected externally.
2. An external load (other than an inertia) is needed to make engine fuel consumption and torque much greater than 0.
3. It's better not to directly specify speed. It's better to apply torque unsing a throttle and let the system determines speed. You can turn on the Speed Control in the Generic Engine block to control speed. Note that you should use a low external throttle since the speed control can't set the final throttle to below the external throttle.