VVC Engine does not idle

Hello,

I have a question regarding the VVC model engine.

The problem is that the engine never idles, specially when it should.

I have turned off the engine start-stop function in ECU unit and also put up a target idle speed in the ECU idle section. However the engine never idles and turns off and on in instances.

I want to know what is causing this specific problem in my model.

Thank you in advance.

[Peter]

Hi Bardia-

Please provide an exact list of steps you used to generate your model in VVC with all VVC UI selections I will replicate your setup to reproduce your issue.

Generally speaking you have to generate a Conventional or Hybrid P0..P4 architecture with a Simulink (as opposed to Simscape) plant model selection for Longitudinal operation with SI Simple Engine, SI Mapped Engine, or SI H2 Engine with SI Controller in the Virtual Vehicle UI.

After the VVC model is generated, open the SI Engine Controller block and uncheck the ESSEnable checkbox to turn off the engine stop-start feature.

Run the model and note the default 750RPM idle during idle periods on the default USFTP75 test cycle.

Thanks,

Peter Maloney

[Bardia]

Hello Mr. Maloney,

I will now brief you on the steps that I have taken for creating the model.

The SI Engine (Conventional vehicle - Simulink) is calibrated from maps and runs with no problem, The gearbox efficiency is also mapped and works perfectly. Note that both of these sets of data is from ADVISOR. My problem with the model is that although the model is (mostly) completely in line with advisor (as in torque and speed values), but the advisor model runs the engine in idle speed in between accelerations in the NEDC cycle, while my engine in the vvc does not do that (The most idle speed that I could get out of it was near 200RPMs.). I would say my main problem is here because this difference can have a big impact on fuel consumption difference between the two models. Since advisor peaks the torque and speed in a fraction of a second and can keep the idle speed throughout the drive cycle yet vvc engine speed turns to near zero. Note that the engine start-stop functionality is already turned off.

And I have another question: Is there a way for me to run the engine in hot mode in VVC instead of cold since it also does impact the emissions and consumption.

Thank you for your help.

Pictures provided below: