Describe the key calibration parameters in modern engine management systems.

Engine calibration involves optimizing multi-dimensional maps for: Spark timing (balancing power, emissions, knock margin across speed/load/temperature), Fuel injection (quantity, timing, multiple injection events, rail pressure), Variable valve timing (phaser angles for volumetric efficiency, residual control), Boost pressure (wastegate/VGT control, compressor surge avoidance), EGR rate (NOx vs. soot trade-off in diesel), Lambda control (stoichiometric for TWC, lean for efficiency), and Transient strategies (tip-in enrichment, cold start). Calibration targets emissions compliance (BS6), performance, driveability, and fuel economy simultaneously.