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PGM-FI System Description - Components

Air Fuel Ratio (A/F) Sensor (Sensor 1) 

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.

GHH418185Courtesy of HONDA, U.S.A., INC.

Secondary HO2S (Sensor 2) 

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.

GHH418186Courtesy of HONDA, U.S.A., INC.

CKP Sensor 

Each of the teeth on the CKP pulse plate passes over it, the CKP sensor pulse signal is delivered to the PCM

CMP Sensor 

Every time one of the protrusions of the CMP pulse plate passes over it, the camshaft position (CMP) sensor pulse signal is delivered.

MAF Sensor/IAT Sensor 1 

The MAF sensor/IAT sensor 1 is attached to the air cleaner to detect the intake air amount and the intake air temperature.