Troubleshooting

Some recommendations and suggestions to help make the IC Engine Powertrain work better:

Symptom

The Simulation fails immediately upon the starting the dynamics phase.

Possible Cause:
  • The Initial conditions of the engine and clutch are not set properly.
  • Connections of the CSE are not consistent with the rest of the model.

Symptom

The engine torque is either much more or much less than I was expecting.

Possible Cause:
  • The throttle scaling has not been set correctly.
  • The units of the torque map are not correct.
  • The engine map is pointing to the wrong .pwr file.

Symptom

The Clutch torque produced is quite noisy with spikes appearing in the signal.

Possible Cause:
  • The clutch stiffness is too high; units might be incorrect.
  • The clutch damping is too little; heavier damping will smooth out curves.

Symptom

The engine stalls as soon as the dynamic simulation starts.

Possible Cause:
  • The initial condition of the engine speed is below the stall speed.
  • The engine inertia is set to a low quantity which causes the engine to drop speed quickly.
  • The initial condition of the gear demand signal is incorrect.
  • The torque demanded by the vehicle is too high and engine is not able to support it.
  • The stall speed is too close to or equal to the idle speed.
  • The sign convention of the direction of applied output torque might be incorrect.
  • The sign convention of the transmission speed input is incorrect.

Try running the anti-stall system if the clutch is disengaged or the vehicle is at neutral at initial conditions.

Symptom

The engine stalls in spite of the anti-stall flag set to 1.

Possible Cause:
  • The Engine inertia is unrealistically low.
  • The negative torque produced by the engine is unusually high.
  • The stall speed is very close to or equal to the idle speed (the engine may stall during transients).
  • The clutch is engaged when vehicle is in gear (the anti-stall system is only designed to prevent an idling engine from stalling).

Try to diagnose by setting a limit on the engine speed derivative (Engine Parameter 8).

Symptom

The engine stalls at gear shifts.

Possible Cause:
  • The engine inertia is unrealistically low.
  • The negative torque produced by the engine is unusually high.

Try to run the anti-stall system if you are not already doing so.

Symptom

Transients are observed at the beginning of the dynamic stage of the simulation.

Possible Cause:
  • The initial conditions are not set correctly. Specifically check the engine speed initial condition.
  • The throttle signal or the transmission speed signal is not hooked correctly.

Symptom

Unexpected spikes at end of gear shifts.

Possible Cause:
  • Clutch too stiff or too little damping.
  • The clutch time constant is too high.

If the clutch slip is non-zero when the clutch starts re-engaging, then reduce the clutch time constant.