Auto Start Stop (Image courtesy: BMW)

The Auto Start Stop System Functioning In Cars Explained


What is the Start Stop system?

The car drivers often tend to keep their engines running even when the vehicle is stopped. This may be at the traffic signals & during heavy traffic. This causes burning of extra fuel which contains rich air-fuel mixture required for idling. Hence to reduce the unnecessary burning of fuel & improve fuel economy, manufacturers developed the 'Start Stop System'.

Auto Start Stop System (Courtesy: Suzuki)
Auto Start Stop System (Courtesy: Suzuki)

The Start Stop system automatically shuts off the engine when the vehicle stops. The system then automatically restarts the engine when the car is again ready to drive off.

A ‘Start stop system' or stop-start system is also known as the Micro-Hybrid system. It cuts down the engine idling time & thereby reducing emissions. A vehicle fitted with Start Stop system considerably improves its fuel efficiency by shutting off the engine during idling and saving the fuel. This helps when the car halts at the traffic signal or in traffic jams. Mahindra claims that its Micro-Hybrid technology improves the fuel economy by about 5 to 10 percent.



You can activate the ‘Micro-Hybrid’ system as follows:

  1. Stop car & press clutch.
  2. Move gear lever to neutral.
  3. Release clutch pedal - the engine will stop after 5 seconds.
  4. The engine won't stop till the car is still moving, even if you follow the above steps.
  5. Press the clutch.
  6. The engine restarts as soon as you press the clutch.
  7. Select the correct gear and move the car.
Scorpio Micro-Hybrid Technology (Courtesy: Mahindra)
Scorpio Micro-Hybrid Technology (Courtesy: Mahindra)

In some sophisticated designs, the Auto Start Stop function does not affect the comfort and safety systems of the vehicle. The Auto Start Stop function will not activate if-

  1. The engine has not reached the normal running temperature.
  2. The battery has inadequate charge.
  3. The AC system is running.
  4. The driver moves the steering wheel.

Some advanced designs also make use of the integrated starter-generator (ISG). It is also known as integrated starter-alternator & regenerative braking used in combination with Start Stop systems.

Following technologies developed by different manufacturers which consist of the Start Stop system:

SL. Name Company
1 Efficient Dynamics BMW
2 Stop and Start Citroën
3 Start&Stop Fiat
4 Start-stop Ford
5 eAssist GM
6 ISG (Intelligent Stop & Go) Hyundai, Kia
7 Stop Start Honda
8 stop-start-technology IKCO
9 Micro Hybrid Mahindra
10 i-Stop Mazda
11 BlueEFFICIENCY Mercedes
12 Idling Stop Nissan
13 stop-start Tata
14 BlueMotion VW
15 DRIVe Volvo

Watch Idling Stop System in action here:

Read More: What is Fuel Economy And how to calculate it?>>

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