What does idle speed mean?

[VanKennedy]

Automobile idle speed refers to an operating state of the engine. When the engine is running and the accelerator pedal is fully released, the engine operates at idle speed. The purpose of automobile idle speed is not about velocity. Engine idle speed is called idle, which can be adjusted by regulating the throttle. When the engine is running, if the accelerator pedal is completely released, the engine will operate at idle speed. When adjusting idle speed, the vehicle speed should not suddenly increase or decrease, otherwise it may cause premature wear to the engine. It's best to have it adjusted at an automotive maintenance department. According to GB18285-2005, idle condition refers to the no-load operating state of the engine. This means the clutch is in the engaged position, the transmission is in neutral (for automatic transmission vehicles, it should be in 'Park' or 'P' gear); for vehicles equipped with a carburetor fuel supply system, the choke is in the fully open position; the accelerator pedal is in the fully released position. High idle condition means meeting all the above conditions (except the last one). The accelerator pedal steadily controls the engine speed at 50% of the rated speed or the high idle speed specified in the manufacturer's technical documentation. In simple terms, idle speed is somewhat similar to a person's resting heart rate. Reducing engine vibration and unstable speed is like when a person has insufficient blood supply to the heart, experiencing palpitations, loud noise, high fuel consumption, and uncomfortable exhaustion.

[DeGarrett]

Idling refers to the state where the engine continues to run while the vehicle is stationary, typically maintaining a speed of around 800 RPM. This is to support the operation of devices such as air conditioning and audio systems. When you're stuck in traffic or waiting at a red light without turning off the engine, this is what idling means. If the idle speed is unstable, the car body may shake severely, which could be due to a dirty throttle or issues with the spark plugs. As a mechanic, I often hear car owners complain about increased fuel consumption—prolonged idling does indeed consume more fuel. It's recommended to regularly clean the air filter to extend the engine's lifespan. When driving, it's best to avoid prolonged idling; using smart start-stop functions can save some fuel, which is friendly to both your wallet and the environment.

[DeBradley]

Idle speed means your car is stationary with the engine still running, typically between 600 to 1000 RPM. For instance, during my daily commute while waiting for my girlfriend to finish work, I keep the air conditioning on with the engine maintaining this state. If unstable, you may feel slight vibrations in the car, affecting comfort. This is usually related to the fuel system, such as clogged fuel injectors or an aging battery. I recommend not letting the engine idle for too long, say more than 10 minutes, as this can increase fuel consumption by over 10%. On hot summer days, idling under a tree to enjoy the cool air is fine, but developing good driving habits like turning off the engine when stepping out can save you a significant amount of money in the long run.

[SanJoy]

Idling refers to the engine running at a low speed when the car is stationary without being turned off, typically to power the air conditioning or audio system. When I take my kids out to play, this is how we stay cool while waiting at traffic lights. If the idle speed is too high, with the RPM jumping to over 1000, it might be due to the engine being too cold or a sensor issue. Remember to check the throttle valve during maintenance, as excessive carbon buildup can affect performance. Reducing idling can lower fuel consumption, which is practical for city driving.

[Bella]

Idling refers to when the vehicle is stationary but the engine is still running, maintaining a low speed of about 700 RPM. Back when I drove an old Jeep, it used to hum loudly at idle, but newer cars are much quieter now. This is mainly to keep internal equipment like the air conditioning functioning. If the idle is unstable, the car may shake or jerk, usually due to intake issues or ignition system faults. My veteran driver advice is to perform regular maintenance—cleaning the throttle body can prevent shaking. Prolonged idling does consume more fuel, especially when warming up the car in winter, but don’t exceed five minutes. Develop the habit of turning off the engine immediately after parking.