ICE-34 — Engine Control

ASSUMPTION — This lesson covers control concepts in general; specific ECU algorithms are not given.

In this lesson you will learn:

• Open vs closed loop
• The torque structure
• Operating modes

1. Open vs Closed Loop

• Open-loop — predefined commands without sensor feedback (e.g., cold start).
• Closed-loop — continuous correction from sensor measurement (e.g., lambda control).

FACT — Modern engine control uses closed loop for most functions, providing stability and accuracy under changing conditions.

2. The Torque Structure

FACT — In modern ECUs the central concept is torque. Driver demand (pedal) becomes a target torque; the ECU coordinates air, fuel and ignition/injection actuators to deliver it. Torque requests from other units (transmission, ESP, hybrid) are merged in this structure (ICE-35).

3. Operating Modes

• Crank/start — first ignition and transition to stable running (ICE-38).
• Idle — stable no-throttle speed (ICE-37).
• Normal driving — broad load/speed range.
• Full load — maximum torque/power.

INTERPRETATION — Each mode has different control objectives; calibration makes the transitions smooth and emissions-compliant.

4. Summary

• Open loop is predefined; closed loop is feedback-based.
• The torque structure is the central coordination framework.
• Start/idle/normal/full-load modes carry different objectives.

5. Sources

• Bosch, Gasoline-Engine Management and Diesel-Engine Management

Next Lesson

• ICE-35 — Torque Control.