РХХ: what is it, the main breakdowns, the working principle

In this article will be considered РХХ, what is it, the principle of action, the basic parameters. Also it will be told about when it is necessary to replace the idle speed regulator on VAZ cars. You know that a modern car is stuffed with a lot of sensors and actuators. This includes the idle speed regulator. With it, the engine speed is maintained . When the PXX breaks, the motor starts to function poorly, symptoms such as unstable rotation of the crankshaft appear, its turns constantly jump. In some cases, it is possible that the engine stalls and does not start.

What is an idle speed regulator?

To begin with it is necessary to consider the external and internal view of RXX. What is this you will learn from this article. It is installed near the throttle, with its help, maintains the speed of the crankshaft at a level of 700 to 900 revolutions per minute. This is done by adjusting the air supply to the throttle assembly. Externally, the idle speed controller looks like a small plastic box, inside of which there are small stepper motors (or a solenoid). But some models have the shape of a cylinder, made of metal. A stepping motor or solenoid drives a metal rod that opens and closes the air supply.

Engine operation at XX

The engine's operation at the lowest rpm is a very heavy duty for him. It starts with the fact that fuel with air is very slowly supplied to the combustion chamber, therefore, the formation of the mixture is ineffective. It should also be taken into account that there is very little pressure in the intake manifold of the engine, so that exhaust gases can be returned to the combustion chamber. Hence it can be concluded that there is a decrease in efficiency, an increase in the toxicity of the exhaust, excessive wear of the elements of the cylinder-piston group. It is worth noting that the device does not have a very high price. The idle speed regulator has a cost of about 400-500 rubles.

No-load regulation

If you recall the carburetor engines, the engine speed at idling was regulated with the help of special screws. During the tuning process it was necessary to control the oxygen content in the exhaust gas, the crankshaft speed. The procedure itself is very laborious and needs a qualified specialist to conduct it. When the first systems of forced fuel injection appeared, the procedure was much simplified.

In fact, РХХ, what is it, considered in the article, is an executive device, rather than a sensor. It is connected to the electronic control unit, which collects all the data on the operation of the motor in real time. Based on the received data, the computer controls all important parameters of the internal combustion engine. It is worth noting that the design of the idle speed regulator is original, as in diesel engines a completely different adjustment scheme is used.

How does РХХ work

So, the above was considered, for which an idle speed regulator is needed. Everything that has been described can be realized only if the air is supplied at idle speed bypassing the throttle. This happens with the help of a bypass channel. Depending on how open this channel is, the air supply changes. Pay attention that at malfunctions of a regulator of idling the lamp «check engine» does not light up in most cases. And remember that the regulator is not a sensor. РХХ is an executive mechanism, as it does not measure anything.

When using bypass РХХ there is only one drawback - it always tries to stabilize the crankshaft rotations. However, during the movement the need for this practically disappears, since it is necessary to stabilize the revolutions only during the switching of speeds or braking.

What are the regulators

Several types of idle speed regulators can be distinguished. Perhaps the simplest is based on solenoids. When a voltage is applied to it, a metal core is pulled out. Therefore, the bypass channel starts 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 produce a very fine adjustment, it is very often necessary to apply a voltage to the solenoid. Before checking the PXX, make sure that the ignition is switched on.

The second type is the rotary regulator. The principle of action is almost similar to the previous one. The only difference is the presence of the rotor, which produces the opening and closing of the bypass channel. But the step-by-step regulator of idling, which consists of 4 windings and a magnet in the form of a ring, became more widespread. The voltage from the electronic control unit can be applied to each of the windings. As a result, the rotor rotates, which opens or closes the bypass channel. Here are such differences are available for different models RXH. What it is, you could learn.

Basic failure of the idle speed regulator

If you are trying to diagnose engine operation yourself, and you have a suspicion that the idle speed regulator has failed, you should know the main symptoms of the failure. And the very first thing is that the turns jump at idle. Also during the gas discharge there is a so-called hovering - the turns are delayed for a certain time on the same value. It is also possible that the engine stalls during speed adventures.

When you turn on powerful consumers, such as headlights, air conditioning, acoustics, there is a decrease in engine speed. It is possible that the motor may not start. It is worth noting that no settings of the VKH RXH are required. In case of failure, a complete replacement is required. The only exception to this rule is the clogging of the bypass channel. Therefore, before performing a PXX replacement, clean this channel.