What is the idle speed of a car engine?
2 Answers
Car engine idle speed is between 700 to 800 revolutions per minute. The effects of engine idling include: 1. Increased engine carbon deposits; 2. Shortened engine lifespan; 3. Overly rich air-fuel mixture in the engine, which can easily damage the catalytic converter; 4. Loosening of the vehicle's braking system, increasing the risk of accidents; 5. Increased exhaust emissions from the vehicle's cylinders. Car idling refers to the engine running without any load, only overcoming internal mechanical friction, without delivering any power output, maintaining the minimum stable operating speed of the engine. The idle speed can be adjusted by modifying the throttle opening and the idle fuel supply.
My car is a small-displacement manual transmission, and I drive mostly in the city. During cold starts, the idle speed is a bit higher, around 1000 to 1200 RPM, but once the engine warms up, it stabilizes at about 700 RPM. In the summer, when the AC is on, I can feel the RPM rise by about a hundred, since the compressor is working. Experienced drivers know that unstable idle speed is something to watch out for—things like a dirty throttle body or worn spark plugs can cause the needle to shake. Last time during maintenance, the mechanic mentioned that newer cars are more fuel-efficient, with some even able to idle at 600 RPM without stalling.
