AIR ASSIST SYSTEM [SKYACTIV-X 2.0]

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Purpose, Outline

• The air assist system supplies the charged intake air to the engine via the supercharger.

• The optimum intake air amount is supplied by operating the air bypass valve according to the engine operation conditions.

Function

• The air assist system operates based on the functions of mainly the following 4 parts.

Supercharger

•  The supercharger supplies the charged intake air inside the cylinder by driving the rotor via the water pump drive belt.

Supercharger clutch

•  The supercharger clutch pulls the armature and engages the clutch depending on the electromagnetic power generated by energizing the coil.

Air bypass valve

•  The air bypass valve is opened/closed and the intake air pressure is adjusted according to the engine operation conditions.

Water-cooled charge air cooler

•  To efficiently burn the intake air and fuel, the charge air cooler cools the intake air which is compressed and heated by the supercharger to increase the intake air density.

Structure

System diagram

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• The air assist system consists of the following parts:

Part name

Reference

Supercharger

(See SUPERCHARGER [SKYACTIV-X 2.0].)

Supercharger clutch

(See SUPERCHARGER CLUTCH [SKYACTIV-X 2.0].)

Air bypass valve

(See AIR BYPASS VALVE [SKYACTIV-X 2.0].)

Water-cooled charge air cooler

(See WATER-COOLED CHARGE AIR COOLER [SKYACTIV-X 2.0].)

Part name	Reference
Supercharger	(See SUPERCHARGER [SKYACTIV-X 2.0].)
Supercharger clutch	(See SUPERCHARGER CLUTCH [SKYACTIV-X 2.0].)
Air bypass valve	(See AIR BYPASS VALVE [SKYACTIV-X 2.0].)
Water-cooled charge air cooler	(See WATER-COOLED CHARGE AIR COOLER [SKYACTIV-X 2.0].)

Operation

• The air assist system operates the supercharger electromagnetic clutch and the air bypass valve according to the engine operation conditions.

• Three patterns of engine operation conditions are described below.

― Ignition is switched OFF

― Supplied intake air amount is insufficient relative to control target value

― Supplied intake air amount is high relative to control target value

Ignition is switched OFF

• The open/closed condition of each valve when the engine is stopped is as follows.

― Supercharger clutch:OFF

― Air bypass valve:closed

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Supplied intake air amount is insufficient relative to control target value

• When the supplied intake air is insufficient relative to the control target value, the air bypass valve is closed and all the exhaust gas of the supercharger is supplied to the engine to enhance boosting.

― Supercharger clutch:ON

― Air bypass valve:closed

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Supplied intake air amount is high relative to control target value

• When the supplied intake air amount is large relative to the control target value or the throttle valve is suddenly closed based on the driver's request, the air bypass valve is opened to make the exhaust gas from the supercharger flow back upstream of the supercharger.

― Supercharger clutch:ON

― Air bypass valve:fully open

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• For supercharger control details, refer to the CONTROL SYSTEM. (See SUPERCHARGER CONTROL [SKYACTIV-X 2.0].)

Supercharger	• The supercharger supplies the charged intake air inside the cylinder by driving the rotor via the water pump drive belt.
Supercharger clutch	• The supercharger clutch pulls the armature and engages the clutch depending on the electromagnetic power generated by energizing the coil.
Air bypass valve	• The air bypass valve is opened/closed and the intake air pressure is adjusted according to the engine operation conditions.
Water-cooled charge air cooler	• To efficiently burn the intake air and fuel, the charge air cooler cools the intake air which is compressed and heated by the supercharger to increase the intake air density.