What is the Principle of Engine Start-Stop?

[Kenneth]

Here is an introduction to the principle and function of automatic start-stop: 1. When the vehicle stops moving due to traffic congestion or at an intersection, the driver presses the brake pedal and shifts to neutral. 2. At this time, the Start/Stop system automatically detects that the engine is idling and not in gear, the wheel speed sensor of the anti-lock system shows zero, and the electronic battery sensor indicates there is enough energy for the next start. 3. When these three conditions are met, the engine automatically stops running. Here are more details about automatic start-stop: (1) Temporary stops during vehicle movement, such as when waiting at a red light. (2) While driving, simply pressing the brake pedal will cause the engine to automatically shut off approximately two seconds after the vehicle comes to a complete stop. Keeping the brake pedal pressed will maintain the engine in the off state. (3) Releasing the brake or turning the steering wheel will automatically restart the engine, allowing immediate acceleration. The entire process remains in the D (Drive) gear state.

[VanSpencer]

I previously studied this start-stop system in detail when getting my car repaired at a 4S shop. At its core, it relies on the vehicle's computer to automatically control engine shutdown and restart. When you brake at a red light, the car senses the stationary state and cuts fuel supply to shut off the engine. During this time, the alternator keeps working, so the AC and audio system continue operating normally. The moment you release the brake pedal, the system immediately sends a signal to restart the engine - the entire process completes within 0.5 seconds without needing to touch the key. This system places high demands on the starter motor and requires an enhanced battery. Once I helped a car owner install an auxiliary battery specifically to protect the main battery. Of course, when the engine is cold and coolant temperature is insufficient, the system won't activate to avoid damaging the engine.