The start-stop system is designed to save fuel and reduce environmental damage from internal combustion engines. Today, most new models have such a system, but many car owners doubt its necessity and effectiveness. Expert mechanics from Indy Auto Man offer an overview of how the start-stop system works and its pros and cons.
How does the start-stop system work on a car?
The first to equip their cars with a start-stop (SS) system were the Germans from the VW AG concern, the French from Citroen, followed by Peugeot. Today, most new European, Japanese, and Korean cars can boast this option.
First of all, the start-stop system on a car is designed to save fuel. According to manufacturers, it allows you to save up to 10% of gasoline, which also reduces harmful emissions.
The algorithm for its operation is quite simple. For an automatic transmission, the engine turns off if the driver presses the brake pedal and the car is stationary for 2-3 seconds. In some models (for example, Audi), the driver can control the process – start-stop works if you press the brake harder. And in very advanced micro-hybrid systems, the electronics can turn off the engine even before the car comes to a complete stop at a traffic light. If the vehicle has a manual transmission, the engine turns off after stopping and moving the selector to neutral. When the engine is off, the generator also does not work. All onboard energy consumers receive it from the battery.
Automatic engine start occurs when the driver releases the brake pedal (in the case of an automatic transmission) or presses the clutch (if the gearbox is manual).
The design of the start-stop system includes a set of sensors, a control unit, and a device for repeated engine starting. In most cars, the latter function is performed by an ordinary starter, perhaps with a reinforced design and a longer service life, because it has to work much more often.
In any case, the long-term operation of the start-stop system requires a powerful battery. In addition, it must be immune to frequent discharges and charges.
Typically, the start-stop system is activated only when moving forward and if the car doors are closed and the driver wears a seat belt. This is done for safety so the owner does not absent-mindedly leave the car whose engine is on.
Finally, the system will not work if the engine is not warmed up, the generator is faulty, or additional electrical consumers are connected – for example, heated windows, mirrors, or seats, which affect the battery charge level.
Advantages and effectiveness of the start-stop system
The benefits of start-stop include, first of all, efficiency and environmental friendliness. The maximum effect is achieved in urban conditions when you often have to stand at traffic lights. Whereas when driving on free country roads, the advantages will tend to be zero.
So how much fuel can you save? Automakers provide different data, sometimes quite impressive. Independent tests have shown that in a car with a powerful gasoline engine, the reduction in consumption reaches 8% if you stick only to the urban cycle, with frequent stops of half a minute, simulating traffic lights. But in traffic jams, the system is forced to shut down, keeping the battery charged. At the same time, the savings drop to 3–4 percent, which is not so significant.
The second advantage of the start-stop function is the silence in the cabin at traffic lights. Another less obvious advantage – the SS simplifies learning how to drive a manual car. If a novice driver stalls when starting from a stop, they just need to press the clutch pedal again (usually, this happens instinctively), and the engine will automatically start again.
Disadvantages and possible problems with the start-stop system
The start-stop system is virtually useless when driving on a highway. One should also remember the high requirements for the battery, constantly loaded with a demanding consumer in the form of a starter.
But most importantly, frequent starts hurt the engine. There is an opinion that in terms of wear and tear, one start of the internal combustion engine is equal to 19 miles of measured driving. Turbocharged engines are most vulnerable since stopping the engine abruptly increases the risk of turbine overheating and breakdown.
The last disadvantage of the start-stop system is its rough operation on some car models. In them, the engine stalls with a noticeable jolt or vibration and then may start with a delay and a loud starter sound.
How to disable the start-stop system
As a rule, the roughness of the operation prompts drivers to turn off the start-stop. The second good reason is fear of the engine life and the expensive battery.
However, there is also an objective need to disengage the system. In reality, start-stop only has an effect when the gasoline engine is turned off for more than 5 seconds and the diesel engine for at least 9–10. In traffic jams, stops are often shorter, and the engine should better run constantly.
There are two ways to turn off the system. The first is by pressing a key (usually “A off” or “Start/Stop off”) on the front panel. But this will deactivate the system only for the trip duration until the driver next starts the engine.
The second option is more radical. It involves software disabling the function and requires the intervention of technical center specialists using specialized equipment.
Is it possible to install a start-stop system?
The advisability of installing such a system independently among specialists causes justified skepticism since the car design will require considerable changes for the correct and safe operation.
However, SS kits for retrofitting several models are still available. With proper skills, you can integrate them yourself by studying the instructions or contacting the service specialists with appropriate qualifications.
But the main thing when equipping a car with a start-stop system is to understand that the engine, conventional starter, and battery will be subject to additional unplanned wear and tear, which can lead to breakdowns. So, if you think this option will perfectly suit your driving style, a better decision is to consider buying another vehicle with start-stop built-in.