Will the RPM Increase When the Air Conditioning is Turned On?
2 Answers
Yes. It is normal for the engine RPM to increase when the car's air conditioning is turned on. Below is some relevant information about the air conditioning system: 1. Air conditioning requires dust removal: The air conditioning system is prone to inhaling dust and bacteria during use, so after prolonged use, the system should undergo a dust and bacteria removal treatment to ensure the health of the passengers. 2. Working principle: When the air conditioning is turned on, the air conditioning compressor is driven by the compressor belt, and the belt's driving force comes from the engine. Therefore, to prevent the engine from stalling due to the additional load at idle, vehicles with electronically controlled fuel injection and belt-driven air conditioning compressors will experience an increase in idle RPM.
I often encounter this issue while driving, especially in summer when turning on the air conditioning, the RPM noticeably increases by a few hundred, and the engine sound becomes slightly louder. This happens because the activation of the AC compressor adds extra load to the engine, prompting the ECU system to automatically raise the RPM to balance the output and prevent stalling or shaking. It's most noticeable at idle, for example, when waiting at a red light, you'll see the tachometer slightly rise. This also increases fuel consumption a bit, so if you're aiming to save on fuel costs, I recommend maintaining steady driving after turning on the AC and avoiding frequent acceleration and braking. Regular checks of the engine and AC system can also prevent abnormalities, such as compressor malfunctions leading to excessively high or unstable RPM, which would then require a visit to the repair shop. In short, this minor fluctuation is a normal phenomenon, designed to ensure the car runs more stably and safely.
