How does the car relay work in the starting system?

The working principle and role of the car relay in the starting system are as follows:

The role of the car relay in the starting system is to control the current of the high-voltage line by controlling the current of the low-voltage line, playing a key role as a current switch. Specifically, when the driver turns the key or presses the start button, the car's electronic control unit (ECU) sends a signal to the starter relay. This signal causes the relay's electromagnet to generate a magnetic field, attracting its contacts to close. Once the contacts are closed, power flows through the ignition coil and fuel system to start the engine running‌.

‌Working principle of relay‌:
The relay is a switching device that uses electromagnetic and electromechanical principles to control the current of the high-voltage line by controlling the current of the low-voltage line. It consists of two parts: the controlled system and the control system. When the input reaches a specific value, the output will suddenly jump from zero to a certain value, realizing the control, protection, regulation, and information transmission of the circuit‌.

‌Specific application of relays in starting systems‌:
In the starting system, the relay starts the high-current motor with a small current, drives the magneto rotor inside the generator to rotate, and then sends an ignition pulse signal to the igniter. The igniter generates an electric spark to ignite the mixed gas in the cylinder to do work. In this way, the relay not only plays the role of a current switch but also closes or opens the contacts through electromagnetic and electromechanical principles to drive or control the operation of related circuits‌.

‌Other applications of relays in automotive circuits‌:
Relays are vital in automotive circuits; almost every automotive circuit cannot do without them. Relays are indispensable in key parts such as headlights, wipers, starters, air conditioners, electric seats, doors and windows, and anti-lock braking systems. Through its multi-contact design, the relay can flexibly switch circuits in different states, significantly enhancing the stability of the circuit and improving the overall system efficiency‌.