At present, regression modeling methods fail to achieve
higher
simulation accuracy, which limits the application of simulation technology
in more fields such as virtual calibration and hardware-in-the-loop
real-time simulation in automotive industry. After fully considering
the abruptness and complexity of engine predictions, a Gaussian process
regression modeling method based on a combined kernel function is
proposed and verified in this study for engine torque, emission, and
temperature predictions. The comparison results with linear regression,
decision tree, support vector machine (abbreviated as SVM), neural
network, and other Gaussian regression methods show that the Gaussian
regression method based on the combined kernel function proposed in
this study can achieve higher prediction accuracy. Fitting results
show that the R
2 value of engine torque
and exhaust gas temperature after the engine turbo (abbreviated as
T4) prediction model reaches 1.00, and the R
2 value of the nitrogen oxide (abbreviated as NOx) prediction
model reaches 0.9999. The model generalization ability verification
test results show that for a totally new world harmonized transient
cycle data, the R
2 value of engine torque
prediction is 0.9993, the R
2 value of
exhaust gas temperature is 0.995, and the R
2 value of NOx emission prediction result is 0.9962. The results of
model generalization ability verification show that the model can
achieve high prediction accuracy for performance prediction, temperature
prediction, and emission prediction under steady-state and transient
operating conditions.