In winter, when the key is gently turned, the engine awakens in the cold wind, and its speed changes like an elaborately choreographed prelude, divided into three delicate and rhythmic chapters. The first chapter is the chapter of ultra-high idle speed, where the speed rises like a warrior to about 1500 rpm. This brief glory lasts for about 30 seconds to 1 minute, and then gradually enters a descending melody. It gracefully slides down to around 1200 rpm, and then opens the second chapter - the melodious chapter of high idle speed. The idle speed here is still higher than normal, but it lasts longer, about five minutes, dancing with the temperature. The low temperature prolongs its duration, while the high temperature accelerates its brevity. In summer, it may only last for two or three minutes, while in the embrace of a cold winter with temperatures below zero, it can take as long as five minutes.

As time goes by, the water temperature quietly climbs, and the engine speed, like a fallen leaf returning to its root, slowly drops to the normal idle speed, around 700 rpm. This normal idle range is like a harmonious symphony, ranging from a minimum of 650 rpm to a maximum of over 800 rpm, all within the elegant range of 600 to 850 rpm.

  What is the secret behind the ultra-high idle speed in the first chapter? It's not for the need of engine warm-up, but for the rapid awakening of the three-way catalyst. The three-way catalyst, this sleeping guardian of environmental protection, needs to reach 400 degrees Celsius to show its strength. Therefore, at the beginning of ignition, the RPM soars, and the ignition timing is quietly shifted later. There is still unburned fuel in the exhaust, which is burned to increase temperature and quickly reach the environmental protection threshold.

  When it comes to the chapter on high idle, the engine is warmed up, the water temperature rises rapidly, and the engine reaches its optimal operating temperature to reduce wear and unleash its potential. The high speed serves both as a preheating process and to prevent stalling. When the car is cold, gasoline atomizes dreamily, necessitating an increase in fuel quantity; engine oil is thick and viscous at low temperatures, doubling the resistance. To ensure smooth driving, the idle speed has to be increased, the throttle is slightly opened, the intake and fuel injection are both increased, and the ignition timing is adjusted, so that the engine can operate safely.

 When will high idle speed come to an end? The key lies in the water temperature. When the water temperature reaches 25 degrees, the idle speed begins to decrease; when it reaches 60 degrees, the idle speed returns to normal, approximately 700 rpm, and everything returns to its usual state. The duration of high idle speed is determined by the temperature. If the coolant temperature rises slowly, the high idle speed will last longer.

  There is no absolute rule for warming up a car. After exceeding the maximum idle speed, set the idle speed to 1200 rpm and start driving. This process takes about 30 seconds to 1 minute. Get in the car, ignite the engine, buckle up the seat belt, turn on the music, put away your phone, activate the navigation, and everything is ready. Although it is possible to drive, the engine has not fully warmed up yet. Driving at low speeds will not damage the engine. The speed should not exceed 60 km/h and the rpm should not exceed 3000 rpm to ensure safety. At this speed, the engine continues to warm up. Don't be impatient or drive on the highway. When the coolant temperature reaches 60 degrees Celsius, which takes about five minutes, you can drive freely.

  Warming up the car at low speed brings dual benefits. Firstly, it accelerates temperature rise, increases RPM, resets the ignition angle, and speeds up the warm-up process. Secondly, it saves fuel. Warming up the car in place increases exhaust emissions and fuel consumption. The vehicle hasn't moved yet, but the gasoline has already been consumed, which is why fuel consumption is high in winter. Therefore, when driving for the first time in the morning, pay attention to both the RPM gauge and the coolant temperature gauge. Once the RPM drops slightly, you can start driving; only when the coolant temperature rises can you drive at high speed.

  Thus, the art of driving lies in delicate perception. Both RPM and water temperature are crucial for driving.