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4.3.11. System of air supply of ACAV (model with 16 valves)

To guarantee optimum efficiency at high frequencies of rotation of the engine and a power maximum at lower frequencies of rotation of the engine, models with 16 valves have an inlet collector with the variable section of a path. The system is called ACAV ("variable acoustic characteristic induction").

The inlet collector is divided to two highways of various length and diameter: a long path (for low power) 650 mm long and with a diameter of 36 mm and a short path (for high power) 370 mm long and with a diameter of 45 mm.

On each end of a casing assembly with a vacuum diaphragm is established. Each diaphragm is connected with an axis of the throttle valve through a pusher. Vacuum diaphragms are connected with electrically the operated electromagnetic valve which is in turn connected with the vacuum pump of the brake system. The pump is installed at an end face of a head of the block of cylinders.

With frequencies of rotation of the engine 1800 revolutions per minute and more than 5080 revolutions per minute of ECU are lower closes the electromagnetic valve, disconnecting vacuum from diaphragms, and throttle valves zakryvytsya. With valves short paths of air supply are closed and the stream of air arrives through a long path.

With frequencies of rotation of the engine between 1800 revolutions per minute and 5080 revolutions per minute of ECU opens the electromagnetic valve. Vacuum influences vacuum diaphragms and opens four throttle valves. With open valves the arriving air passes both through short, and through long paths for obtaining the maximum power.

Check

PERFORMANCE ORDER
1. To check system, to start the engine in the idling mode. To slowly increase the frequency of rotation of the engine and to watch vacuum pushers of a diaphragm. At about 1800 revolutions per minute pushers have to influence diaphragms.
2. To check operation of the electromagnetic valve, to pick up the vacuum phone from a diaphragm. To start the engine in the idling mode. To place a finger on the end of a pipe; vacuum has to be absent in a pipe. At slow increase in frequency of rotation of the engine do1800 revolutions per minute vacuum in a pipe has to be felt.

BLOCK OF ACAV VALVES

Removal

PERFORMANCE ORDER
1. To remove an inlet collector.
2. To remove the fuel highway.
3. To remove vacuum hoses from the fuel regulator of pressure and ACAV diaphragm hose from a tee.
4. To unscrew three bolts fixing the block of valves to a head of the block of cylinders and to remove it together with laying.
5. To check that throttle valves opened freely and easily.

VACUUM DIAPHRAGM

The block with a vacuum diaphragm of ACAV


Removal

PERFORMANCE ORDER
1. To remove a vacuum hose from the diaphragm case.
2. To unscrew two bolts fixing the block with a vacuum diaphragm to the block of valves and to remove the block.

ELECTROMAGNETIC VALVE

Electromagnetic valve

1 – nut of fastening of the electromagnetic valve,

2 – electrical wiring socket,

3 – connection of a hose

The electromagnetic adjusting valve is installed at the left end face of a head of the block of cylinders.

Removal

PERFORMANCE ORDER
1. To wring out a bracket and to remove the electric socket.
2. To unscrew a nut of fastening of the valve, to remove the valve and to remove vacuum hoses from the valve.