PGM-FI System Description - Components
Air Fuel Ratio (A/F) Sensor (Sensor 1)
The air fuel ratio (A/F) sensor (Sensor 1) is installed on the warm up three way catalytic converter (WU-TWC). Air fuel ratio control performs fuel injection control based on the oxygen density detected in exhaust gas in order to bring the intake mixture in the vicinity of a target air fuel ratio. This high-precision air fuel ratio control is achieved by detecting a correction value with an A/F sensor (Sensor 1) and then applying further correction with a secondary heated oxygen sensor (secondary HO2S) (Sensor 2).The sensor element and the heater inside the A/F sensor (Sensor 1) have a layered construction of a plate-shaped zirconia element whose inside and outside are coated with platinum and a built-in platinum heater. A ceramic coating diffusion layer on the platinum electrode on the outside of the element creates an atmospheric chamber between the platinum electrode inside the element and the heater.
Secondary HO2S (Sensor 2)
The secondary heated oxygen sensor (secondary HO2S) (Sensor 2) is installed downstream of the warm up three way catalytic converter (WU-TWC). It detects the oxygen density in the exhaust gas passing through the catalyst and outputs it to the powertrain control module (PCM) to enable the high-precision air fuel ratio control, which cannot be achieved only with an A/F sensor (Sensor 1).Inside secondary HO2S (Sensor 2) is a test tube shaped zirconia element whose inside and outside surfaces are coated with platinum. The inside surface is exposed to the atmosphere, while the outside surface is within the exhaust gas.A ceramic heater is equipped inside the element in order to shorten sensor reaction time and to enable output that is constantly stable.
CKP Sensor
The CKP sensor is attached to the engine block. Each of the 58 teeth on the CKP pulse plate passing over the CKP Sensor generates a pulse signal that is delivered to the PCM.
CMP Sensor
The camshaft position (CMP) sensor is attached to the back cover of the front bank. Every time one of the five protrusions of the pulse plate attached to the camshaft passes over CMP sensor, it generates a pulse signal that is delivered to the PCM.
MAF Sensor/IAT Sensor
The MAF sensor/IAT sensor is located in the intake air passage and contains a hot wire sensor, a cold wire sensor and a thermistor. The resistance of the hot wire sensor, the cold wire sensor, 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 outputted to the PCM.
Manifold Absolute Pressure (MAP) Sensor
The MAP sensor converts manifold absolute pressure into electrical signals to the PCM.
Knock Sensor
The knock control system adjusts the ignition timing to minimize knock.
Barometric Pressure (BARO) Sensor
The BARO sensor is inside the PCM. It converts atmospheric pressure into a voltage signal that is used by the PCM to modify the basic duration of the fuel injection discharge.
Engine Coolant Temperature (ECT) Sensors 1 and 2
ECT sensors 1 and 2 are temperature dependent resistors (thermistors). The resistance decreases as the engine coolant temperature increases.