Carburetors have for a long time dominated the gasoline engines. The solo function of a carburetor is to supply the required air-fuel mixture at various engine operating conditions. The introduction of gasoline fuel injection or electronic fuel injection has made the air-fuel mixing process more accurate by precisely defining the limits of injection.
Introduction of stringent emission norms have led to the banishment of carburetors except in few motorcycles. The fuel injection system improved the fuel efficiency, engine performance and lessened the emissions.
Gasoline can be injected either externally in the inlet manifold where it gets mixed with the air before being delivered to the combustion chamber, or directly inside the combustion chamber.
External Injection System:
In this system, the air-fuel mixture is formed inside the inlet manifold. The air-fuel mixture is then supplied to the combustion chamber during the suction stroke. There are 2 types of external fuel injection system, namely:-
Multi Point Fuel Injection (MPFI):
In an MPFI system, an injector is provided for each cylinder of an engine. The injectors inject fuel directly in front of the intake valve. Some examples of an MPFI are K-Jetronic, L-Jetronic, LH-Jetronic, etc.
Throttle Body Fuel Injection:
This system uses only a single injector in the throttle body. The injector injects the fuel intermittently over the throttle valve and the inlet manifold supplies the air-fuel mixture to the various cylinders of an engine.
Direct or Internal Fuel Injection:
In a direct type, fuel is injected directly inside the combustion chamber. The solenoid operated injectors are mounted over the cylinder head. The air-fuel mixture formation takes place inside the combustion chamber. The main advantage of direct injection is that an engine can operate with lean mixture. The system is commonly known as Gasoline Direct Injection (GDI).
Introduction of stringent emission norms have led to the banishment of carburetors except in few motorcycles. The fuel injection system improved the fuel efficiency, engine performance and lessened the emissions.
Gasoline can be injected either externally in the inlet manifold where it gets mixed with the air before being delivered to the combustion chamber, or directly inside the combustion chamber.
External Injection System:
In this system, the air-fuel mixture is formed inside the inlet manifold. The air-fuel mixture is then supplied to the combustion chamber during the suction stroke. There are 2 types of external fuel injection system, namely:-
- Multi Point Fuel Injection (MPFI)
- Throttle Body or Single Point Injection
Multi Point Fuel Injection (MPFI):
In an MPFI system, an injector is provided for each cylinder of an engine. The injectors inject fuel directly in front of the intake valve. Some examples of an MPFI are K-Jetronic, L-Jetronic, LH-Jetronic, etc.
Throttle Body Fuel Injection:
This system uses only a single injector in the throttle body. The injector injects the fuel intermittently over the throttle valve and the inlet manifold supplies the air-fuel mixture to the various cylinders of an engine.
Direct or Internal Fuel Injection:
In a direct type, fuel is injected directly inside the combustion chamber. The solenoid operated injectors are mounted over the cylinder head. The air-fuel mixture formation takes place inside the combustion chamber. The main advantage of direct injection is that an engine can operate with lean mixture. The system is commonly known as Gasoline Direct Injection (GDI).
No comments:
Post a Comment