PGM-FI System Description - Injection Control
Fuel injection controls include fuel injection amount control, fuel cut control and fuel pump control. Adopting PGM-FI (programmed-fuel injection) technology enables accurate fuel controls, which contributes to increased engine power and decreased fuel consumption.
Fuel Injection Duration
The fuel injection duration is determined by adding correction values to a basic injection duration. The powertrain control module (PCM) controls the amount of fuel injection by the length of time the injector is energized.
Fuel Injection Timing
The fuel injection timing is determined by the PCM, which calculates the injection time for each cylinder based on the signals sent from the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor. The PCM then controls the time to energize the injector.
CKP Sensor
The CKP sensor is attached to the oil pan. Each of the 58 teeth on the crankshaft pulse plate passes over it, a pulse signal is delivered to the PCM.
CMP Sensor
The camshaft position (CMP) sensor is attached to the cylinder head. Every time one of the three protrusions of the camshaft pulley passes over it, a pulse signal is delivered.
Fuel Injector
The fuel injector for a gaseous fuel supply has multiple holes. The nozzle with multiple holes increases the fuel atomization and improves the mixing with the surrounding air. When the coil in the injector is energized, the plunger is pulled in. The needle valve, which is integral with the plunger, is pulled on full. Then, the injector sprays the pressurized fuel which is controlled by the fuel pressure regulator.
MAF Sensor/IAT Sensor
The mass air flow (MAF) sensor/intake air temperature (IAT) sensor contains a hot wire, a cold film, and a thermistor. The sensor is in the intake air passage. The resistance of the hot wire, the cold film, and the thermistor changes due to intake air temperature and air flow. The control circuit in the MAF sensor controls the current to keep the hot wire at a set temperature. The current is converted to voltage in the control circuit, then sent as an input to the PCM.