Engine idling: operation and consumption

Engine idle is the specific amount of time your engine is running when you are not moving forward. The behavior of this depends on many factors, and gasoline engines in particular are equipped with a regulator dedicated to this phase of engine speed.

⚙️ How does the engine idle?

From the moment you start the car, the engine will start. During the acceleration and deceleration phases, its power and torque will vary significantly. Most often we talk about engine speed, because they mean rotational speed from this to tours in a minute... While driving, you can read it on your car dashboard on the counter.

However, when you are in neutral, the engine continues to run, but at idle speed. Thus, engine idle most often indicates phases when you are standing or driving at very low speeds, such as in the case of traffic jams.

At par, this corresponds to 20 rpm... Depending on the car model and engine power, it can vary up to 900 rpm.

Note : Gasoline engines are more powerful than diesel engines. Indeed, they can go up to 8 rpm.

🚘 What is the flow rate of a stationary vehicle when the engine is idling?

The fact that the engine is idling does not mean that it does not consume fuel to keep running. Indeed, even if consumption is very low, it still amounts to 0,8 liters of fuel on average for all types of engines (gasoline and diesel).

On the most modern cars, engine idle phases are limited due to the availability of technology. Start and stop... It automatically turns off the engine when the car is idling or comes to a complete stop. Thus, this system was installed in cars for three different reasons:

• Reduced fuel consumption : When the engine is idling, it continues to consume fuel. Thus, by neutralizing this idle fuel consumption, the vehicle's fuel consumption can be reduced.
• Ecological approach : Reducing vehicle emissions helps protect the environment and protect the planet from global warming.
• Limiting vehicle wear : When the car engine is idling, it does not have the optimum temperature and the fuel does not burn completely. Thus, it increases the clogging of the engine system and can damage its mechanical parts.

⚠️ What are the causes of unstable idle speed?

When you experience unstable idling, your engine will experience large rpm fluctuations, which can cause it to stall. This situation can be caused by several different elements:

• La temperature sensor does not work well in cold weather;
• Le air flow meterdefective;
• Malfunction associated with ignition system ;
• Un injector have the flu;
• Le Butterfly bodyfilthy;
• Generator no longer gives enough energy;
• A false contact is present on one of the electrical harnesses;
• La Lambda probedefective;
• Le calculatingrequires reprogramming.

If you notice more and more erratic idling, it will be necessary to get to the garage as quickly as possible so that they can determine the root of the problem and fix it.

🔎 Why is there a clicking sound when the engine is idling?

When driving in a vehicle with an engine at idle speed, you may hear clicking sounds. This sound appears because you have one of the following three problems:

1. Combustion anomaly : one of the parts responsible for combustion no longer works correctly;
2. Malfunction rocker arms : if they have a gap setting, it will need to be adjusted as quickly as possible;
3. Defect c hydraulic valve lifters : real connections between the camshaft and the valve stems, they no longer fulfill their role and cause clicks.

Engine idling is a phase of engine speed that should preferably be avoided to save fuel and prevent premature wear of engine components. If your vehicle does not have Start and Stop technology, try turning off the engine when stopped for more than 10 seconds. If your engine stalls or runs erratically at idle, use our garage comparator to make an appointment with a mechanic at the best price!