Fuel injection system — design description [Toyota Camry XV10]

An electric fuel pump located inside the fuel tank delivers fuel under constant pressure to the fuel rail, which distributes it to the fuel injectors. The fuel injectors spray fuel near the intake valves. The amount of fuel delivered by the injectors is controlled by the electronic control unit (ECM). Some models have a cold start injector. The pressure regulator maintains the pressure in the fuel system depending on the vacuum in the intake manifold.

Air supply system

The air supply system consists of an air filter, an air flow meter, and a throttle body. The air flow meter provides the ECM with information about the amount of air entering the engine. Based on the amount and temperature of air entering the engine, the ECM determines the amount of fuel supplied to the injectors.

Electronic control system

All the information from the sensors is analyzed by the ECM unit of the electronic control system and on this basis the unit determines the appropriate ignition timing and fuel mixture composition. The ECM unit controls the fuel injectors by determining the pulse width, i.e. the length of time when the injector is open, to provide a richer or leaner fuel mixture.