Air pollution and global warming have urged automotive manufacturers to improve the efficiency of internal combustion engines to reduce fuel consumption and emissions. This necessity, along with efforts toward engine downsizing, has led to increasingly complex engine systems. Moreover, the absence of proper calibration in modern engines results only in wasted time and costs during engine design and development. Therefore, calibration methods must also improve along with engine technologies.

The growing number of actuators in engine management system significantly increases the time and cost of ECU calibration. One of the fundamental yet crucial approaches to reduce calibration effort is to identify the appropriate operational range of actuators. This, in turn, allows defining practical boundaries for calibration variables such as valve opening and closing angles, injection phase angles, and the relative ratio of each phase. This help reduce the number of required engine-level calibration tests.

This research was carried out at Irankhodro Powertrain Company (IPCO), concentrating on the development of turbocharged gasoline direct injection engines equipped with variable valve timing. These are currently the most advanced engines developed domestically. In such engines, extracting optimal actuator operating ranges is critical for initiating ECU mapping and improving the speed and quality of the calibration process. Without proper constraint of these ranges, the mapping process can become highly complex, time-consuming, or even infeasible.

In this study, base calibration variables such as air-fuel ratio, spark timing, valve timing, injection timing, injection split ratio, and fuel pressure were collected from several similar engines. Suitable actuator operating ranges were derived through benchmarking. The engine map was divided into three regions. This segmentation helps constrain the test domain and reduce the number of possible calibration states, eliminating the need for exhaustive point-by-point mapping. This method reduced the operational domain of the actuators for calibration tests up to 99%.