Does Engine Start-Stop Save Fuel or Waste Fuel?
2 Answers
Engine start-stop is more fuel-efficient, and here are the reasons: 1. The English name for engine auto start-stop is STOP&START, abbreviated as STT. The STT intelligent fuel-saving system is a set of systems that control engine start and stop. 2. Auto start-stop is achieved by implanting an enhanced motor with idle start-stop functionality into a traditional engine, allowing the engine to completely shut off when the vehicle meets idle stop conditions. 3. When the vehicle needs to start moving again, the idle start-stop motor system quickly responds to the driver's start command, rapidly restarting the engine for seamless engagement, thereby significantly reducing fuel consumption and exhaust emissions.
I've driven for many years and found that the auto start-stop function generally saves fuel, especially in urban areas with heavy traffic or frequent traffic lights. For example, during my commute in Beijing, whenever I encountered a long red light, the engine would automatically shut off, saving fuel that would otherwise be wasted during idling. However, it doesn’t help with short stops—like temporary halts lasting just a few seconds—because the engine restart process actually consumes extra fuel due to the additional fuel needed for ignition. Overall, if each stop lasts more than about 7 seconds, it can save 10%-15% on fuel costs. Personally, I saved around a hundred yuan per month on gas. That said, the vibration during startup can be annoying, especially on hot summer days when the air conditioning is running—the cabin gets stuffy after the engine shuts off. Additionally, frequent start-stop cycles increase wear on the battery and starter motor. For older vehicles, the cost of potential repairs might outweigh the fuel savings, so I recommend using it often in new cars but cautiously in older ones.
