Diesel engine can work on very lean air fuel ratio of the order of 30 : 1. A petrol engine can also work on such a lean ratio provided

Diesel engine can work on very lean air fuel ratio of the order of 30 : 1. A petrol engine can also work on such a lean ratio provided cannot work as it is impossible.
- For cold starting (simply when your engine parts are not warmed) - 9 : 1 (rich of fuel)
- For Idling (when you stop at signal without turning off engine) - 12 : 1 (rich mixture)
- For cruising (when you run engine at constant medium/economy speed) - 16 : 1 (lean mixture)
- When you accelerate bike/car - 13 : 1 (rich mixture but require less fuel than idling)