Why does my simulation model, using SimDriveline, keep giving me errors regarding the Generic engine?

Dear community,

Currently, I am working on a project where I have to simulate a truck-trailer combination. Regarding the driveline, I came across SimDriveline (through youtube and the mathworks site) and I would love to make use of these functions within the matlab Simulink database. I've been trying to make use of the Generic Engineblock by building the open throttle model which is explained in the videos. The model includes the generic engine block, a torque converter, a simple gear, a differential, wheels and a vehicle body. Also, the inertia are specified, the initial engine speed is altered and there is a solver to compute the physical signals. The solver used for the simulation is ode15s.

After a few seconds of running, the simulation shows some errors and they keep coming back while using multiple configurations:

Using the Tabuled power data with standard data provided by the block (since I have the data regarding power and torque of the engines which I want to use for the simulation), I get the errormessage "At time 7.431..., an assertion is triggered. Enginespeed has exceeded the last value of the Speed vector parameter." After that, my simulation stops computing.

Using the same block and the Tabuled torque data for the model parameterization, i get the same message at roughly the same timestamp.

Using the normalized 3rd order polynomial (which doesn't really suit my application, but I wanted to try everything), the simulation doesnt even hold out for 7 seconds..: "At time 4.74..., an assertion is triggered. Engine speed has exceeded the maximum speed parameter." After that the simulation stops.

My question is if I can use either of the first two model parameterization methods with the standard input which matlab simscape offers, without having to change all too many parameters. If I could get this to work, I would be able to experiment with various parameters and slowly accomplish my goals from there. Right now, I just feel stuck.

I'm not sure what to change (given that the speed vector and the torque/power vector cannot be changed). I'm hoping that someone can help me with this problem.

Kind regards,

Steven Boonstra Student Automotive Engineering

Answer 1

[Martin]

The Generic Engine will issue an assertion terminating simulation if the speed is too high. This is as if a real engine exceeded its allowable speed and was either shut down by a fail safe system or caused internal damage. With open throttle the engine is generating power and the power must go somewhere. This can be counteracted by a sufficient load through losses on accelerating inertia. As it keeps accelerating, the engine will eventually reach a speed a that will exceed its limits. This is as if a driver had a vehicle in neutral with the accelerator fully engaged. In only a few seconds, either a controller or governor would need to stop it, or the engine would fail. In R2017b, an optional redline controller is added to the Generic Engine. This controller reduces throttle when engine speed exceeds a defined limit.