Barometric Pressure (Baro) Sensor Construction/Operation; Knock Sensor (Ks) Function; Knock Sensor (Ks) Construction/Operation - Mazda RX-8 2004 Service Highlights

BAROMETRIC PRESSURE (BARO) SENSOR CONSTRUCTION/OPERATION

• The BARO sensor is installed on the secondary
air injection pump bracket.
• The piezoelectric element is enclosed in the
sensor and the electric potential difference
changes as the BARO drops. The output voltage
lowers as the BARO drops.
BARO SENSOR
End Of Sie

KNOCK SENSOR (KS) FUNCTION

• Detects knocking.
End Of Sie

KNOCK SENSOR (KS) CONSTRUCTION/OPERATION

• Installed on the left of the rear rotor housing (plug
hole side).
• Converts knocking vibration into a voltage value
using the piezoelectric effect of the semi-
conductor, and sends the value to the PCM.
• The piezoelectric effect is a phenomenon in which
a difference in electric potential is produced on
the surface of a piezoelectric element by the
application of tensile load or pressure from a
certain direction. Tensile load and pressure
applied to the KS originates from cylinder block
vibration caused by abnormal combustion in the
engine. The difference in electric potential, which
results from the strain by the vibration, is sent to
the PCM as a knocking signal.
01–40–52
CONTROL SYSTEM
BARO SENSOR OUTPUT VOLTAGE CHARACTERISTIC
PCM
5
CPU
0
BARO SENSOR
CHU014018210S02
CHU0140S066
CHU0140S076
CHU014018920S01
CHU014018920S02
KS
CHU0140S068