Does Idling Consume More Fuel?

[CaydenMarie]

Engine fuel consumption increases with higher RPM. Below is more information about engine idling: 1. During idling, the engine must be ready to respond to the driver's starting operation at any time. When starting the car, it transitions from a stationary to a moving state, requiring the engine to generate more torque than during normal driving. 2. Due to the inherent programming of the car's electronic fuel injection system, the fuel injector sprays slightly more fuel per cycle during idling compared to normal driving. Additionally, higher engine RPM results in increased fuel consumption. Extended content: The meaning of car idling refers to the state where the car is started under any load condition without needing to perform external work. The vehicle's ECU controls the throttle solenoid valve's air intake to maintain the engine's minimum and stable RPM.

[McIsabela]

Honestly, idling fuel consumption is quite alarming. I once tested my old 1.6L car specifically - with AC on and idling stationary for 1 hour, the fuel gauge dropped by a full notch, working out to about 1.5 liters consumed. It's even scarier during summer traffic jams when you're crawling in stop-and-go traffic with AC running. Some veteran drivers think restarting the engine wastes more fuel, but actually shutting it off becomes more economical if idling exceeds 30 seconds. Especially with current fuel prices being so high, it's best to develop the habit of turning off the engine during prolonged stops. I've heard some cities are now fining drivers for idling with AC on - just the fuel cost alone is painful to think about, not to mention carbon buildup issues.

[LolaRose]

Ride-hailing drivers have something to say: idling is absolutely a fuel consumption black hole! Our fleet conducted an experiment – idling with AC on in summer for one hour consumes fuel equivalent to driving 5 km for nothing. During morning/evening rush hours stuck on bridges, the worst scenario is stop-and-go traffic. The transmission refuses to upshift while engine RPM fluctuates wildly. The most wasteful situation is idling with AC on while waiting – the displayed fuel consumption can skyrocket to 20L/100km. Later we got smarter: turning off the engine if waiting exceeds 3 minutes, or directly heading to paid parking lots for orders. Modern cars' auto start-stop systems address this issue, though many people disable them due to annoyance – but they genuinely save significant fuel costs.

[JadeFitz]

From an environmental perspective, idling is pure waste. Gasoline turns into exhaust and is emitted from the vehicle, burning money for nothing while polluting the environment. Especially for older diesel vehicles, the black smoke emission is even more severe. Nowadays, new cars in the EU must be equipped with automatic start-stop systems precisely to cut off idling fuel consumption. In China, cities like Beijing, Shanghai, and Guangzhou have already legislated against prolonged idling, with fines of 200 yuan if caught. Technically speaking, the engine cannot reach operating temperature while idling in a parked state, leading to increasingly more fuel being burned. I've seen truck drivers using the heater to sleep in winter, burning half a tank of fuel overnight, which is particularly not worth it.