What is the Principle of Engine Speed Limiting?
3 Answers
The principle of engine speed limiting is that when the ignition device loses the ignition signal, it loses its ignition function, causing the engine to shut off. Once the engine shuts off, the rotational speed decreases. Specific reasons for the engine speed limiting principle: When the driver's speed continuously increases to the set speed limit and also reaches the set buffer time without deceleration, the system enforces the speed limit. The throttle automatically adjusts and cannot supply more fuel. Once the speed drops below the set limit, the speed limit is lifted, and the fuel system returns to normal. The car engine speed limiter system includes: Throttle pedal, electronic control unit, motor, throttle mechanism. The driver presses the throttle pedal according to the power required for driving, and the throttle pedal position sensor converts the collected throttle pedal position signal into an electrical signal.
I found that the principle of engine speed limiting is primarily achieved through an electronic control system. This system is commonly referred to as the ECU, or the vehicle's onboard computer, which continuously monitors the engine's RPM. Once the RPM reaches a preset maximum value, the ECU intervenes—for example, by delaying ignition timing or temporarily cutting off fuel supply. This prevents the engine from accelerating further, keeping it within a safe range. Why is this necessary? Because at high speeds, engine components such as pistons or connecting rods are prone to excessive stress, leading to overheating or even breakage. In modern vehicles, this function can also be adjusted based on driving modes, such as sport mode allowing slightly higher RPM. From my experience, many car owners overlook this protection, resulting in premature engine failure. Overall, it's a smart design that both protects hardware and enhances reliability. I recommend drivers pay attention to the tachometer while driving and avoid prolonged periods near the redline zone.
I've been driving for many years, and once on the highway, I floored the accelerator, but the RPM suddenly got stuck and stopped increasing, feeling like the acceleration halted. Later, I learned this was the ECU limiting the speed—it uses sensors to monitor engine RPM, and once it approaches a dangerous point, it controls the fuel injection system to reduce fuel or adjust ignition timing to prevent overspeeding. This design is incredibly practical because, in the past, older cars without speed limits often ended up needing major repairs due to over-revving. Now, every time I push the engine too hard, it automatically brakes a bit, giving me peace of mind. More importantly, it avoids the risk of accidents: overspeeding can lead to engine runaway or component explosions. As an average car owner, I think this feature is like an invisible bodyguard for the car, saving me a lot on repair costs. During daily driving, paying attention to abnormal RPM can help prevent issues before they arise.
