Case Study: Nissan halves NOx and CO emissions and cuts AFR calibration time by 90% with MathWorks

Nissan Improves Emission Performance and Reduces Calibration Time for Air-Fuel Ratio Controllers

Nissan needed to improve the performance and reduce calibration time for an existing air‑fuel ratio (AFR) sliding‑mode controller already in mass production, while changing only controller gain values and not the controller structure. To accelerate development and avoid the previous manual, trial‑and‑error tuning that took over 30 hours, Nissan turned to MathWorks’ Model‑Based Design tools, including MATLAB, Simulink, Optimization Toolbox, Simulink Design Optimization, and System Identification Toolbox.

Using MathWorks products, Nissan identified an accurate plant model from measured data with System Identification Toolbox, used Optimization Toolbox and Control System Toolbox to compute and tune optimal SMC gains, and automated calibration with Simulink Design Optimization. The MathWorks‑based solution cut calibration time by about 90% (from ~35 hours to ~3.5 hours), reduced NOx and CO emissions by half or more under certain conditions, and delivered consistent, outsourceable calibration quality that Nissan is now extending to other powertrain controls.

Nissan

Hiroshi Katoh

Deputy General Manager