Do automatic transmission cars have idle speed?
3 Answers
Automatic transmission cars do have idle speed. Here is some introduction about idle speed in automatic transmissions: 1. The idle state of an automatic transmission refers to an operating condition when the engine is running without load. When the accelerator pedal is completely released while the engine is running, the engine enters idle state. 2. When adjusting idle speed, the RPM should not fluctuate abruptly as this may cause premature wear to the engine. It's best to have it adjusted at an automotive repair facility. 3. Idle speed refers to the engine running without any load, only overcoming the frictional resistance of its internal components, without delivering any power output.
I've been driving automatic transmission cars for years, and they do have idle speed: when the car comes to a complete stop, such as in D gear with the brake pressed or waiting in P gear, the engine maintains a low-speed operation, typically between 700-900 RPM, keeping the car ready to start without stalling. Idling has many benefits—it keeps the air conditioning, lights, and audio system functioning normally, making driving more convenient; it also reduces wear during startup and fuel consumption fluctuations, especially useful during short stops like at traffic lights. However, from an energy-saving perspective, it's important to note: I've tested that idling for an hour can waste 0.5-1 liters of gasoline and can lead to engine carbon buildup issues. Therefore, I avoid excessive idling for more than a minute or two in traffic jams or during long stops, as it can increase maintenance costs. Modern car models have smarter idle management, with some start-stop systems automatically shutting off the engine to save fuel, but the core function is for safety and convenience. Beginners just need to get used to controlling the brake to ensure smooth driving. In summary, idling is standard for automatic transmissions, and its reasonable use offers more advantages than disadvantages.
As someone who understands automotive technology principles, I can confirm that automatic transmission vehicles are designed with an idle speed function. When the vehicle comes to a complete stop, the ECU system automatically maintains the engine at its minimum operating RPM to prevent stalling and ensure immediate response to acceleration commands. For instance, when braking in D gear or parking in P gear, the idle speed adjusts based on load conditions – it typically increases by 50-100 RPM to compensate for power demands when using air conditioning or preparing for uphill driving. This feature is crucial for both driving comfort and functionality: it maintains the operation of onboard systems like cooling fans or electric power steering. Technically, idling reduces cold-start wear but excessive use may lead to increased emissions and fuel waste; optimal solutions include selecting eco-mode or start-stop technology vehicles that automatically balance these factors. We recommend owners monitor idle speed stability to prevent control module malfunctions, ensuring engine health and trouble-free operation.
