What is the approximate ideal (stoichiometric) air-fuel ratio for complete combustion in a petrol (gasoline) engine?
14.7 : 1
Petrol Engine Stoichiometric Air-Fuel Ratio
The stoichiometric air-fuel ratio represents the ideal ratio where just enough air is supplied for complete combustion of the fuel. For petrol (gasoline), this ideal ratio ensures that all fuel is consumed with the available oxygen, theoretically producing only $CO_2$ and $H_2O$.
Ideal Ratio Value
The commonly accepted stoichiometric air-fuel ratio by mass for gasoline combustion is approximately 14.7:1.
Importance in Engines
- This 14.7:1 ratio is crucial for achieving complete combustion.
- Modern engines use this value as a reference point for fuel injection and ignition timing to optimize performance, fuel economy, and emissions control.
- Operating conditions often require ratios slightly richer or leaner than stoichiometric, but 14.7:1 represents the ideal chemical balance.
Therefore, 14.7:1 is the standard approximation for the ideal air-fuel ratio in petrol engines.
Final Answer: The final answer is $\boxed{\text{14.7 : 1}}$Important Questions from Fuels and Combustion
Theoretically, ignition in an engine should occur at:
In a Distributor less ignition system the distributor is replaced by:
In distributor-less ignition systems, ignition can be adjusted manually by:
A ballast resistor is used in which of the following systems?
What among the following is the firing order of a four-cylinder engine?
