As shown in figure 1 the multipoint fuel injection system in which there is independent injection for each cylinder mounted in the inlet port. This provides improved mixture preparation and distribution in comparison to single point and carburettor systems. Air supply is controlled by the throttle body and the butterfly valve fitted in the intake system.
In single point injection. a single injector for the entire engine is mounted above throttle buttery valve which feeds the engine in a manner similar to the carburettor system. But in multipoint injection when the independent injector is placed above below the throttle valve, it is called indirect multi point injection.
The working and layout of mechanically operated multi point fuel injection system is shown in Figure 2. An electrically operated fuel pressure pump is mounted near the fuel tank to pump fuel from the fuel tank to the metering distributor through a filter at a specified pressure of about 0.7 bar. The relief valve provided between the pressure pump and metering distributor returns the excess fuel to the tank there by keeping the fuel supply to the metering distributor at constant pressure. The metering distributor supplies fuel to each injector in turn The injector is held closed by spring until the fuel pressure opes it to deliver atomised spray of fuel.
In single point injection. a single injector for the entire engine is mounted above throttle buttery valve which feeds the engine in a manner similar to the carburettor system. But in multipoint injection when the independent injector is placed above below the throttle valve, it is called indirect multi point injection.
The working and layout of mechanically operated multi point fuel injection system is shown in Figure 2. An electrically operated fuel pressure pump is mounted near the fuel tank to pump fuel from the fuel tank to the metering distributor through a filter at a specified pressure of about 0.7 bar. The relief valve provided between the pressure pump and metering distributor returns the excess fuel to the tank there by keeping the fuel supply to the metering distributor at constant pressure. The metering distributor supplies fuel to each injector in turn The injector is held closed by spring until the fuel pressure opes it to deliver atomised spray of fuel.
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