The Role of Ignition Advance Angle

[JonathanFitz]

The role of the ignition advance angle is to ensure that the maximum gas expansion phase occurs during the piston's power stroke under various operating conditions. Here are the factors influencing the optimal ignition angle: 1. Cylinder temperature and pressure. Higher temperatures and pressures result in faster combustion, requiring a smaller ignition advance angle. Factors affecting cylinder temperature and pressure include: engine compression ratio, ambient temperature, cylinder temperature, and load. 2. Gasoline octane rating. Higher octane ratings indicate stronger anti-knock properties, allowing for a larger ignition advance angle. 3. Air-fuel mixture ratio. Both overly rich and lean mixtures burn slower, necessitating an increased ignition advance angle. This primarily depends on throttle opening and altitude.