РХХ: what is it, main breakdowns, principle of operation

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

In this article, IAC will be considered, what it is, the principle of operation, the main parameters. It will also talk about when it is necessary to replace the idle speed controller on VAZ cars. You know that a modern car is crammed with many sensors and actuators. These include the idle speed controller. With its help, the engine speed is maintained. If the IAC fails, the motor begins to function poorly, symptoms such as unstable rotation of the crankshaft appear, its speed constantly jumps. In some cases, it is possible that the engine stalls and does not start.

What is an idle speed controller?

To begin with, it is worth considering the external and internal appearance of the IAC. What it is, you will learn from this article. It is installed near the throttle valve, with its help, the crankshaft speed is maintained at a level of 700 to 900 rpm. This is done by adjusting the air supply to the throttle assembly. Externally, the idle speed regulator looks like a small plastic box, insidewhich are small stepper motors (or solenoid). But some models have the shape of a cylinder, made of metal. A stepper motor or solenoid drives a metal rod that opens and closes the air supply.

Engine running at XX

The operation of the engine at the lowest speed is a very difficult mode for him. It’s worth starting with the fact that fuel with air is very slowly supplied to the combustion chamber, therefore, the formation of the mixture proceeds inefficiently. It should also be borne in mind that there is very little pressure in the engine intake manifold, so exhaust gases can get back into the combustion chamber. From this we can conclude that there is a decrease in efficiency, an increase in exhaust toxicity, and excessive wear of the elements of the cylinder-piston group. It is worth noting that the device is not very expensive. The idle speed regulator has a cost of about 400-500 rubles.

Idle control

If you remember the carburetor engines, then the engine idle speed was regulated with the help of special screws. During the tuning process, it was necessary to control the oxygen content in the exhaust gases, the crankshaft speed. The procedure itself is very time-consuming and requires a qualified specialist to carry it out. When the first forced fuel injection systems appeared, the procedure was greatly simplified.

In fact, IAC, what it is, discussed in the article, is an actuator, not a sensor. He's boundwith an electronic control unit that collects all data on the operation of the motor in real time. Based on the data obtained, the vehicle's ECU monitors all the most important parameters of the internal combustion engine. It is worth noting that the design of the idle speed controller is original, since diesel engines use a completely different adjustment scheme.

How RHX works

So, above it was considered what the idle speed regulator is needed for. Everything that has been described can only be realized if, at idle, air is supplied bypassing the throttle valve. This happens with the help of a bypass channel. Depending on how open this channel is, the air supply changes. Please note that in the event of malfunctions of the idle speed controller, the “check engine” lamp does not light up in most cases. And remember that a regulator is not a sensor. IAC is an actuator as it does not measure anything.

When using a bypass IAC, the only drawback is that it always tries to stabilize the crankshaft speed. True, while driving, the need for this practically disappears, since it is necessary to stabilize the speed only during gear shifting or braking.

What are regulators

There are several types of idle speed controllers. Perhaps the simplest is based on solenoids. When voltage is applied to it, the metal core is pulled out. Consequently, the bypass channel begins to close, reducing the air supply. And vice versa. But there is a small drawback. Regulators of this type have only two positions - open and closed channel. To make a very fine adjustment, you need to apply voltage to the solenoid very often. Before checking the IAC, make sure it has power when the ignition is on.

The second type is a rotary regulator. The principle of operation is almost similar to the previous one. The only difference is the presence of a rotor that opens and closes the bypass channel. But the stepping idle speed controller, which consists of 4 windings and a magnet in the form of a ring, has become more widespread. Each of the windings is energized by an electronic control unit. As a result, the rotor rotates, which opens or closes the bypass channel. These are the differences between different IAC models. What it is, you were able to assimilate.

Main breakdowns of the idle speed controller

If you are trying to diagnose the operation of the engine yourself, and you suspect that the idle speed controller is out of order, you should find out the main symptoms of a breakdown. And the very first is that the revs jump at idle. Also, during the discharge of gas, the so-called freeze occurs - the revolutions are delayed for a while at one value. It is also possible that the engine stalls during speed adventures.

When you turn on powerful consumers, such as lightheadlights, air conditioning, acoustics, there is a decrease in engine speed. It is possible that the engine may not start at all. It is worth noting that the IAC VAZ does not require any settings. In case of failure, a complete replacement will be required. The only exception to the rule is the clogging of the bypass channel. Therefore, before replacing the IAC, clean this channel.