ICE-41 — Emission Calibration

ASSUMPTION — This lesson covers emission calibration conceptually; numeric limits vary by region/year.

In this lesson you will learn:

• The goals
• The NOx/soot/efficiency trade-off
• The role of test cycles

1. Goals and Constraints

Emission calibration tunes the engine to stay below regulation limits on defined test cycles while preserving efficiency and driveability.

FACT — Calibration holds NOx, particulate (soot), CO and HC within limits while targeting fuel consumption and drive quality — goals that often conflict.

2. The NOx–Soot–Efficiency Triangle

FACT — In diesels, NOx and soot are inversely related: lowering combustion temperature reduces NOx but may increase soot and/or efficiency loss. Emission calibration finds an acceptable point using EGR + injection strategy + SCR.

3. Test Cycles

FACT — Emissions are measured over standard drive cycles (e.g., WLTP, NEDC, EPA) and real-driving conditions (RDE). Calibration must meet limits on both.

4. Trade-offs

INTERPRETATION — Emission calibration constantly balances “cleanest” vs “most efficient”. The optimum depends on the engine and aftertreatment for a given regulation target.

5. Summary

• Emission calibration meets limits while preserving efficiency/driveability.
• The NOx/soot/efficiency triangle is the core trade-off.
• Test cycles and RDE set the target.

6. Sources

• Bosch, Emissions Control Technology and Diesel-Engine Management

Next Lesson

• ICE-42 — On-Board Diagnostics (OBD).