Operation; Fail-Safe Function - Mazda RX-8 2004 Service Highlights

• Two oil nozzles are adopted on each rotor in order to improve lubrication in the side housing and side seal in
accordance with the adoption of the side exhaust system. They are tilted toward the side housing to inject oil
directly to the side housing.

Operation

• The oil discharging mechanism consists of the plunger and differential plunger driven by the driving worm. The
driving worm is driven by the eccentric shaft through the driven gear.
• The amount of oil discharged is controlled by change in the stroke of the plunger and the rotation of the control
pin attached to the stepping motor according to the signal from the PCM.
• The operation of the stepping motor is monitored by the positioning switch and it ensures the optimum amount
of oil discharge according to the driving condition.
• The oil nozzle receives the barometric pressure from the air hose to prevent the negative pressure from the
engine being applied to the oil inlet. Also, a one-way check valve has been adopted to prevent oil from flowing
out of the air hose side when the engine is under positive pressure.

Fail-safe function

• Fail-safe function operates when the engine senses a failure in the stepping motor and the positioning switch.
• When the fail-safe function operates, the PCM keeps the control pin at the minimum stroke position and the oil
supply is only in proportion to the engine rotation rate. Thus, the minimum amount of oil at each engine rotation
rate is supplied.
• Normal driving is possible when the amount of the oil required by the engine is within the minimum oil
discharge.
• When the amount of the oil required by the engine is more than the minimum oil discharge, fuel injection is
restricted, increased engine rotation is suppressed, and seizure of each seal inside the engine is prevented.
End Of Sie
01–11–6
LUBRICATION
OIL NOZZLES
SIDE
HOUSING
OIL OUTLET
OIL NOZZLES
SIDE HOUSING
ROTOR
HOUSING
AIR HOSE SIDE
ONE-WAY
CHECK VALVE
OIL INLET
HOUSING SIDE
CHU0111S016
CHU0111S008