Orifice Tube Assembly
The orifice tube assembly is a section of tubing connecting the exhaust system to the intake manifold. The assembly provides the flow path for the EGR to the intake manifold and also contains the metering orifice and 2 pressure pick-up tubes. The internal metering orifice creates a measurable pressure drop across it as the EGR valve opens and closes. This pressure differential across the orifice is picked up by the DPFE sensor which provides feedback to the PCM.
Scheme 13
Supercharger Assembly
The supercharger assembly is a positive displacement pump. Its purpose is to supply an excess volume of intake air to the engine by increasing air pressure and density in the intake manifold. The supercharger assembly incorporates the bypass system to reduce air handling losses when boost is not required, resulting in better fuel economy. When integrated on the engine, the supercharger increases torque across the entire engine operating range from 25 to 50 percent without compromising driveability or emissions. The supercharger is matched to the engine by its displacement and belt ratio, and can provide excess airflow at any engine speed. It contains 2 screw-type 3-lobed rotors. The helical shape and specialized porting provide a smooth discharge flow and a low level of noise during operation. The rotors are supported by ball bearings in front and needle bearings at the rear. The drive gears are pressed into place; therefore, the supercharger is replaced as a unit and is not repairable.
Scheme 14
Supercharger Bypass (SCB) Solenoid/(Thermactor Air Control Solenoid/Vacuum Valve Assembly)
The SCB solenoid is used to control intake manifold vacuum to the vacuum bypass actuator. This part is replaced under the part name of thermactor air control solenoid/vacuum valve assembly (part number 9H465). The PCM transmits an output signal to the SCB solenoid, thereby activating the solenoid to apply stored vacuum from the reservoir to the actuator when an undesirable condition occurs in the engine. Once the engine condition has been corrected, the solenoid will be deactivated by the PCM, allowing engine intake manifold vacuum to control the actuator. The SCB solenoid is normally de-energized.
Scheme 15
Vacuum Reservoir Assembly
The vacuum reservoir assembly stores vacuum that is applied to the vacuum actuator when a condition such as overheating or a critical sensor failure is generated. This allows the vacuum actuator to bypass the supercharger.
