What is the ignition closing angle of the car?

Automobile ignition closing angle is a technical term in traditional automobile ignition system (mechanical contact ignition system).

Angle of rotation of distributor drive shaft (camshaft) during closing of power-off contact in distributor (i.e. during energizing of primary coil of ignition coil). Also known as the primary winding power-on time.

When the structure of the distributor interruption device is fixed (related to the number of engine cylinders), the closing angle of the contact is also fixed.

However, when the engine speed changes, the speed of the distributor drive shaft will also change (the distributor drive shaft is driven by the camshaft of the engine), that is, the speed (angular velocity) of the distributor drive shaft will also change, and the closing angle value is fixed, so the contact closing time will change (that is, the power-on time will change).

Extended data:

The control of the closing angle has the following characteristics.

1, which changes with the change of power supply voltage, that is, the closing angle decreases with the increase of voltage.

2. As the speed changes, that is, the speed increases, the closing angle will increase. Usually, during the design of the ignition control system, the characteristics of the ignition closing angle obtained by experiments are stored in the memory of the electronic control unit as shown in the figure.

When the engine is working, ECU determines and controls the energization time of the ignition coil according to the characteristics of engine speed, battery voltage and closing angle, so as to control the closing angle.

Reference source: Baidu Encyclopedia-Closed Angle