This device provides air to all engine components. It consists of an air filter, an air intake pipe, a throttle body, an idle control assembly, a fast idle mechanism and an air intake manifold. A resonator built into the air intake pipe provides noise reduction from the air sucked into the pipe.
Throttle body
The throttle body contains two auxiliary channels and one main channel in the center. To prevent icing under certain weather conditions of the throttle valves and channel walls, the lower part of the housing is heated with coolant. A sensor is attached to the primary valve to monitor changes in throttle opening width. An air buffer is used to slow the throttle as it approaches the closed position.
Engine idle control
The correct air/fuel ratio during idling is controlled by the on-board computer using solenoid valves such as idle control valve, high idle control valve, and idle air control valve during A/C operation. All of these valves, with the exception of the last one, change the flow of air through the intake manifold. The A/C joint valve opens the throttle when the ECU electrically activates the air conditioner.
The idle control valve is designed to compensate for reduced idle speed caused by electrical and other engine loads. This is achieved by the fact that at the right time the valve launches additional air into the intake manifold. By increasing the air flow, the motor shaft speed increases to the set value of 750±50 rpm. The responsiveness of the valve depends on the magnitude of the voltage change at the FR terminal of the generator. The valve also begins to step down the speed of the warming engine shaft as soon as the temperature of the coolant reaches 55°C. To prevent erratic operation of the engine immediately after the first strokes, the valve is set open during starter engagement and a short time after starting to ensure that sufficient air is supplied to the air intake manifold. The high idle control valve prevents erratic operation of the engine during warm-up, when the idle speed should be higher. This valve also allows additional air into the intake manifold when the atmospheric pressure drops below 660 mmHg.
Solenoid control valve x.x. during the operation of the air conditioner, it maintains the speed of x.x. within 750±50 rpm with the air conditioner on. The valve acts on the idle air conditioning control diaphragm, which opens the throttle to increase idle speed. The valve remains open also at low coolant temperatures (immediately after launch), thus providing stable revolutions x.x. regardless of the position of the air conditioner switch.
Idle speed controller (bypass circuit)
Fuel cut occurs at a certain position or angle of the throttle valve. If the position of this valve is changed in order to adjust the idle speed, then the position or cut-off angle also changes and the device may stop cutting off the fuel supply at the right time. To solve this problem, an adjustment bypass channel is laid in the throttle body. This channel makes it possible to change the flow of air passing through the throttle valve into the air intake manifold without changing the position of the throttle itself.
However, the idle speed usually does not require adjustment.
High idle control mechanism
To prevent erratic operation of the engine during its warm-up, it is necessary to set it to a higher idle speed. The bypass valve is controlled by a thermocouple plunger. When the thermocouple is cold, the valve is open. When the thermocouple heats up, the valve closes. Therefore, when the engine, and hence the thermocouple, is cold, more air enters the air intake manifold, and the engine runs faster than usual. When the engine temperature begins to reach operating temperature, the valve begins to close, reducing the additional air flow.