Does Coasting in Neutral Save Fuel?
2 Answers
Coasting in neutral does not save fuel and can sometimes even consume more fuel, primarily due to the working mechanism of fuel-injected engines. Fuel-injected engines determine the amount of fuel injection based on computer programming. When the car is in gear and the driver releases the accelerator, the computer puts the vehicle into coasting mode, during which the engine does not inject fuel for a significant period. However, if neutral is selected, the computer switches the vehicle to idle mode, and the engine continues to inject fuel. This is why coasting in neutral can sometimes use more fuel. Additional Information: 1. When a vehicle is coasting in neutral, the connection between the engine and the drive wheels is lost. The car moves forward by its own inertia, and the engine can no longer provide resistance to the drive wheels. In such a situation, if an emergency occurs, the entire braking force must be provided by the brakes alone. However, the braking force that the brakes can provide is limited, leading to longer stopping distances and an increased risk of accidents. 2. For older car models, coasting in neutral could indeed save some fuel, which led many drivers to develop a habit of shifting to neutral whenever possible. However, nowadays, fuel-injected engine models have become mainstream in the market. Therefore, the answer to whether coasting in neutral saves fuel is clear: it does not save fuel and can sometimes consume more, in addition to being detrimental to driving safety.
I've been driving for over 30 years and have deep personal experience with coasting in neutral. In earlier years when driving older manual transmission cars like the Santana, coasting in neutral did save some fuel because carburetor-era engines consumed less fuel at low speeds. But modern cars are completely different - they all use electronic fuel injection systems. When coasting in gear, the ECU automatically cuts or reduces fuel injection, whereas in neutral it has to maintain idle speed by injecting fuel, actually consuming more. I've tested this with an onboard computer - coasting in gear saves about 0.5L per 100km on the same route. More importantly, there's the safety aspect. Coasting downhill in neutral removes engine braking, making it easier to lose control on steep slopes or during emergency braking. I've witnessed several accidents caused by this. Saving a little fuel isn't worth compromising safety - I recommend developing the habit of coasting in gear.
