What is i3s?
How does the i3s system Work?
This technology is developed by Hero MotoCorp and implemented in the Hero Splendor iSmart bike. This system automatically switches OFF the engine when not needed. It then switches the engine back ON when you simply press the clutch. When you stop the bike, the i3S system puts the engine into hibernate or sleep mode.
The Idle Stop-Start System turns off the engine after waiting for about 5 seconds, e.g., at a traffic signal. The system then restarts the engine automatically as soon as you press the clutch. So, when the rider wants to go, the engine starts by simply pressing the clutch again. That's it. You don't have to follow the routine procedure to re-start it. This prevents the running of the engine from idling when not needed. Thus, it improves mileage.
Some more information on the company website.