Start-stop system: What are its pros and cons?

Publié le Traduit avec l'aide de l'IA à partir de notre article original (source :

The start-stop system is found in almost all new cars today, at least in the European Union. The start-stop system can automatically turn off the engine whenever the car stops and is idle.

Thanks to engine shutdown, this system is supposed to save fuel, but also reduce the amount of emissions. Is it always the case, though? In this article, we will shed light on this topic.

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History of the start-stop system in a nutshell

The first device that worked on a principle similar to the start-stop system was developed by the Toyota car company in 1964. A little later, the Fiat car company came up with a similar design, which it named City Matic, and in the 90s, this system came to the Volkswagen Golf Mk3 Ecomatic.

The start-stop system in cars sold in the European Union began to be implemented massively with the arrival of the Euro 5 emission standard.

The start-stop system today:

As mentioned, the start-stop system can automatically turn off the engine if the vehicle stops and is idle. If the start-stop system turns off the engine and the driver wants to continue driving, press the clutch pedal, and the engine will start automatically.

Cars equipped with a start-stop system have a special starter, which has a more powerful electric motor, and quieter operation, and its life expectancy should be significantly higher than the life of a classic starter.

However, for the proper functioning of this system, in addition to a special starter, several sensors, and sensors are needed to check whether the engine is idling, whether the car's wheels are not moving and whether the battery has enough energy to restart the engine.

If all these conditions are met, the engine will shut down. However, after pressing the clutch, the engine starts quietly, and the driver can continue driving again.

Advantages of the start-stop system:

The advantage of this system is the reduction of fuel consumption and emission production. These advantages are most apparent when driving in heavy city traffic and being subject to traffic jams.

Manufacturers of cars equipped with a start-stop system report a reduction in fuel consumption of approximately 10%, depending on the type of vehicle and engine.

However, it should be added that despite the stated reduced fuel consumption, the start-stop system is not very popular among car enthusiasts, and many of them turn it off immediately after starting the car.

Disadvantages of the start-stop system:

The mentioned advantages of the start-stop system are very debatable because they are based purely on the operation of the car in an urban environment, or convoys when the engine is idling for a long time, and this, moreover when the engine is properly warmed up to its operating temperature.

The start-stop system is not always tuned correctly, so it turns off the engine even when cold. The lifespan of the starter and battery is also questionable, which is significantly shortened when using this system.

In addition, the start-stop system impacts the comfort of the car crew, because if the engine is not running, the air conditioning compressor does not work either, which can be very unpleasant on hot days. The start-stop system also worsens traffic flow, as the engine needs some time to start before it moves from one place.

Extending the time when the driver can start from the spot can lead to dangerous situations, especially if you are trying to get out of the side road onto the main road along which another car is approaching.

The last and probably the most important reason why the start-stop system is so damned is that it will confirm that the fuel economy is only minimal in real traffic. In the case of short drives in cold weather, when the start-stop system shuts down a cold engine, the fuel consumption may be even bigger.

Watch a short video demonstration of how the start-stop system works: