Does the Engine Auto Start-Stop Save Fuel?

[CoraAnn]

According to the instructions for the auto start-stop function, idling for more than one second can save fuel. In congested road conditions, the auto start-stop function can save up to about 15% of fuel, and even more if the traffic is heavier. Issues brought by start-stop technology: 1. Increased fuel consumption: The auto start-stop technology is mainly used in traffic jams, where the engine is often in a hot state. The engine can typically start at 350 RPM, which is nearly half the idle speed. Assuming there are no other loads besides the engine's internal resistance during startup and the necessary equipment such as the transmission's loss, the fuel consumption will definitely be less than during idle conditions. 2. Frequent starts can cause wear to the engine: The engine's internal lubrication mainly relies on the oil film. Given that the auto start-stop duration is very short, the oil pumped up by the oil pump will not completely drain back, and sufficient oil remains on the friction components. The lubrication of friction components during startup, especially during a hot start at such low RPM and short duration, has no significant adverse effects. The belief that it causes significant engine wear applies to cold starts and high-temperature cold start conditions.

[VonLuke]

The car I previously drove had an auto start-stop function, and honestly, this feature is particularly useful in city traffic jams. When stopping at a red light, the engine automatically shuts off, avoiding unnecessary fuel consumption during idling. My actual measured fuel consumption was about 7% lower than before, saving me dozens of dollars on gas each month. The operation is very simple—just press the brake pedal a bit deeper to trigger it, and the engine automatically restarts when you start moving. Of course, this feature is useless on highways or in suburban areas; it's most effective in congested urban roads. Over time, the battery can easily deplete, so it's necessary to check it regularly or upgrade to a stronger one; otherwise, it might malfunction in winter. But overall, it helps car owners save fuel and money while also reducing carbon emissions, which is good for the environment. I think it's a smart little design worth recommending to friends who commute daily.

[DiMalia]

I've always been a fan of energy-saving and carbon-reducing lifestyles, and auto start-stop is a great eco-friendly assistant. It turns off the engine when the car is stationary, such as at traffic lights or in traffic jams, significantly reducing unnecessary fuel waste. From what I understand, it can save 5-10% on fuel in city driving. Small savings add up, and over a year, it can reduce emissions by several kilograms. This is good for air quality and also saves money. I've tracked my fuel consumption through an app, and it's indeed noticeably lower. Of course, it's important to ensure the car is in suitable condition, like having sufficient battery charge. Overall, this technology promotes green commuting, and I should continue using it.

[VonSara]

I've been driving for twenty years, and the auto start-stop feature does save fuel, but it depends on the scenario. In the city, frequent engine shutdowns at red lights reduce idle fuel consumption—I estimate it saves about 8% on fuel costs. On the highway, this feature is useless and even adds extra burden to the engine. Operationally, there aren't major issues, though occasionally it feels like the car starts a bit slower. Overall, it's a practical fuel-saving tool, and I recommend using it only in urban traffic jams.