One of essential elements control of the water pumping station is a pressure switch. It provides automatic switching on and off of the pump, controlling the water supply to the tank according to given parameters. There are no clear recommendations on what the values ​​​​of the lower and upper pressure limits should be. Each consumer decides this individually within the limits of permissible norms and instructions.

The device and principle of operation of the water pressure switch

Structurally, the relay is made in the form of a compact unit with maximum and minimum pressure springs, the tension of which is regulated by nuts. The membrane connected to the springs reacts to changes in the pressure force. Upon reaching the minimum value, the spring weakens, at the maximum level, it is compressed more strongly. The force exerted on the springs causes the opening (closing) of the relay contacts, turning the pump off or on.

The presence of a relay in the water supply system allows you to provide a constant pressure in the system and the necessary water pressure. The pump is controlled automatically. Properly set, they ensure its periodic shutdown, which contributes to a significant increase in the period of trouble-free service.

The sequence of operation of the pumping station under the control of the relay is as follows:

• The pump pumps water into the tank.
• The water pressure is constantly increasing, which can be tracked on the pressure gauge.
• When the set upper pressure limit is reached, the relay is activated and turns off the pump.
• As the water pumped into the tank is used up, the pressure decreases. When it reaches the lower level, the pump will turn on again and the cycle will repeat.

Device diagram and constituent elements typical pressure switch

The main parameters of the relay operation:

• Lower pressure (switch-on level). The relay contacts that turn on the pump are closed, and water enters the tank.
• Upper pressure (off level). The relay contacts open, the pump turns off.
• Pressure range - the difference between the two previous indicators.
• The value of the maximum allowable shutdown pressure.

Setting the pressure switch

During the assembly process of the pumping station, special attention is paid to setting the pressure switch. The ease of use, as well as the period of trouble-free service of all components of the device, depends on how correctly its limiting levels are set.

At the first stage, you need to check the pressure that was created in the tank during the manufacture of the pumping station. Typically, the factory setting is set to on at 1.5 atmospheres, and off at 2.5 atmospheres. This is checked with an empty tank and the pumping station disconnected from the mains. It is recommended to check with an automotive mechanical pressure gauge. It is placed in a metal case, so the measurements are more accurate than using electronic or plastic pressure gauges. Their readings can be affected by both the air temperature in the room and the level of battery charge. It is desirable that the scale limit of the pressure gauge be as small as possible. Because on a scale of, for example, 50 atmospheres, it will be very difficult to accurately measure one atmosphere.

To check the pressure in the tank, you need to unscrew the cap that closes the spool, connect a pressure gauge and take a reading on its scale. The air pressure should continue to be checked periodically, for example once a month. In this case, water must be completely removed from the tank by turning off the pump and opening all taps.

Another option is also possible - carefully monitor the shutdown pressure of the pump. If it has increased, this will mean a decrease in air pressure in the tank. The lower the air pressure, the more water can be created. However, the pressure spread from a completely filled to a practically empty tank is large, and all this will depend on the preferences of the consumer.

Having chosen the desired mode of operation, you need to set it by bleeding excess air for this, or pump it up additionally. It must be borne in mind that one should not reduce the pressure to a value of less than one atmosphere, and also pump it too much. Due to the small amount of air, the rubber container filled with water inside the tank will touch its walls and be wiped. And excess air will not make it possible to pump in a lot of water, since a significant part of the tank volume will be occupied by air.

Setting the pump on and off pressure levels

Which are supplied assembled, the pressure switch is pre-configured for the best option. But when it is installed from various elements at the place of operation, the relay must be configured. This is due to the need to ensure an effective relationship between the relay settings and the volume of the tank and the pump head. In addition, it may be necessary to change the initial setting of the pressure switch. The procedure for this should be as follows:

In practice, the power of the pumps is chosen such that it does not allow pumping the tank to the extreme limit. Typically, the cut-off pressure is set a couple of atmospheres above the turn-on threshold.

It is also possible to set pressure limits that differ from the recommended values. In this way, you can set your own version of the operating mode of the pumping station. Moreover, when setting the pressure difference with a small nut, one must proceed from the fact that the starting point of reference should be the lower level set by the large nut. You can set the upper level only within the limits for which the system is designed. In addition, rubber hoses and other plumbing also withstand pressure, not higher than the calculated one. All this must be taken into account when installing the pumping station. In addition, the excessive pressure of water from the tap is often completely unnecessary and uncomfortable.

Pressure switch adjustment

Pressure switch adjustment is practiced in cases where it is necessary to set the levels of upper and lower pressures in setpoints. For example, you want to set the upper pressure to 3 atmospheres, the lower - 1.7 atmospheres. The adjustment process is as follows:

• Turn on the pump and pump water into the tank to the pressure on the pressure gauge of 3 atmospheres.
• Switch off the pump.
• Open the relay cover and slowly turn the small nut until the relay operates. Turning the nut clockwise means an increase in pressure, in the opposite direction - a decrease. The upper level is set - 3 atmospheres.
• Open the tap and drain the water from the tank to the pressure value on the pressure gauge of 1.7 atmospheres.
• Close the tap.
• Open the relay cover and slowly turn the large nut until the contacts actuate. The lower level is set - 1.7 atmospheres. It should be slightly higher than the air pressure in the tank.

If asked high pressure to turn off and low to turn on, the tank is filled with a large amount of water, and there is no need to turn on the pump often. The inconvenience arises only because of the large pressure difference when the tank is full or almost empty. In other cases, when the pressure range is small, and the pump often has to be pumped up, the water pressure in the system is uniform and quite comfortable.

In the next article, you will learn the most common connection schemes.

Your carburetor may be equipped with a solenoid valve that prevents the engine from idling when the ignition is off, the solenoid valve is usually located on the outside of the carburetor. If your car won't start at all or starts with great difficulty, then the problem is probably the carburetor solenoid valve that needs to be adjusted.

Tools and materials:

• carburettor solenoid valve
• tachometer
• screwdrivers

Process:

1. Install a tachometer.
2. Start your car's engine and let it warm up.
3. Using the nut located on the end of the carburetor solenoid valve, you need to set a certain number of idle speeds (about 700 per minute).
4. Next, you must disconnect the wiring that comes from the carburetor solenoid valve, after which the speed will decrease.
5. Adjust the position of the thrust screw of the throttle actuator by turning the screw with a screwdriver (clockwise - increase the speed, counterclockwise - decrease) until the tachometer needle stops at the desired value (see your car's operating instructions).
6. If a lean air mixture screw is installed (instead of a throttle actuator thrust screw), then the idle speed is adjusted as follows: turning the air mixture lean screw clockwise reduces the speed, and counterclockwise increases it.
7. Finally, connect the wiring that comes from the carburetor solenoid valve.

An integral part of every scooter is carburettor starter or, as it is also called - scooter carburetor solenoid valve.

What is a starter

Starting enricher (electrovalve)- this device is designed to supply an additional amount of air-fuel mixture to the combustion chamber during a cold start of the scooter engine. The fact is that when starting the scooter on a cold one, the engine needs an enriched mixture. Just the supply of such a mixture provides carburettor solenoid valve. With a good starting enricher and no breakdowns in other elements of the motor, the scooter engine starts easily even at a temperature of about zero degrees.

Scooter starter device

There are two types of starting enrichers - manual and automatic.

Manual (mechanical) starting enricher requires adjustment - it must be opened at startup and closed after the engine warms up using a cable on the steering wheel. But manually opening and closing the additional mixture supply channel is inconvenient. Automatic starting enricher (thermoelectric valve) is installed on most modern 2t and 4t scooters. We will learn about the device of the automatic starting enricher further.

The scooter carburetor has a small additional fuel chamber 7, which is connected to the main float chamber 8 through the start jet 9. The tube from the chamber 7 leads to the mixing chamber into which air is supplied and from which the air-gasoline mixture enters the engine. In the mixing chamber, damper 6 can move, similar to carburetor throttle, only much smaller. Just like a throttle valve, there is a spring-loaded needle in the starting valve that closes the fuel channel when the valve is lowered. Valve body 1 is wrapped with thermal insulation (polyethylene foam) and closed with a rubber boot. Such concentrator design used on almost all modern scooters.

Older models may use design without electric heater, heat is transferred to the drive through a copper heat-conducting cylinder directly from the scooter engine cylinder, and instead of powder with a heating element, membrane. One cavity of the bulb, where it is located, is connected through a thermal valve to the intake manifold, which is fixed to the cylinder head.

Working principle of scooter carburetor solenoid valve

When engine cold damper with spool needle 6 is raised as high as possible (open). The needle opens the fuel supply channel, and the shutter opens the air supply hole. At the first engine speed, a vacuum is created in the emulsion channel and the gasoline in chamber 7 is sucked into the engine through channel A, causing a strong mixture enrichment and facilitating the first flashes in the engine. After the engine has started but not yet warmed up, it still needs rich mixture. The enricher works at the same time as a parallel carburetor - gasoline enters it through jet 9, mixes with air and enters the engine.

When the engine is running, alternating current from its generator is always supplied to the contacts of the ceramic heater 2 of the thermal electrovalve of the start-up system. Heater 2 warms up drive 3. As engine warm-up and drive, the stem gradually extends by 3 ... 4 mm and through the pusher 5 drives the damper. In this way, the engine warms up together with the thermoelectric valve, the spool with the needle lowers and blocks the air and fuel channels, and the mixture gradually becomes leaner. After 3 ... 5 minutes, the damper closes completely and the degree of enrichment of the mixture on a hot engine is regulated only carburetor idle system.

When the engine is stopped valve stops heating, the damper drive cools down (the powder is compressed) and under the action of the spring 10 the pusher 5, the stem 4 and the damper 6 return to their original position, opening the channels for subsequent start-up. Cooling and return to its original position also occurs within a few minutes.

The disadvantage of the enricher of this type is that it functions separately from the engine. For example, very often, especially in warm weather, while the engine is still hot and it still does not need to enrich the mixture, the thermocouple is already cooling down. We start the engine and it gets a rich mixture.

The principle of operation of the start-up enricher of the second type (with a membrane)

Cold valve open. After starting the engine, a vacuum occurs in the collector and through thermal valve supplied to the membrane. As a result of low pressure, the membrane rises and opens the channel for additional air supply. As the cylinder head warms up, the valve closes and the damper with the needle lowers under the action of the spring, blocking the additional fuel supply.

With this design principle, the connection with the actual temperature of the engine is maintained, and fuel dosage performed more correctly.

Solenoid valve The carburetor, also referred to as the idle speed regulator, is a carburetor component designed to save fuel consumption in carbureted internal combustion engines. A malfunctioning solenoid valve and its incorrect operation can lead to increased fuel consumption and to the fact that the car engine stalls at idle.

The principle of operation of the carburetor solenoid valve

The solenoid valve of the carburetor is called upon to regulate the supply of the fuel mixture bypassing the throttle, which is controlled by the accelerator pedal. At idle, fuel enters the internal combustion engine intake manifold through a separate channel. That is why the solenoid valve is also called the vehicle idle speed control. The main purpose of the valve is to stop the fuel supply in inertial modes, which, for example, allows engine braking and coasting.

In gasoline carburetor engines, the valve is installed directly into the carburetor and is part of the auto idle economizer system. The valve is controlled by the electronic control unit of the system; when an impulse arrives, the valve needle retracts and closes the fuel supply bypassing the valve. After the motor is started, power is supplied from the control unit and the valve begins its work, which consists of two cycles:

• on the first stroke, the valve opens, as a result of which air enters the chamber and mixes with the fuel;
• at the second stage, the air channel is blocked and the fuel channel is opened, as a result of which the fuel-air mixture enters the engine.

The movement of the shut-off needle of the valve is carried out by incoming electrical impulses from the control unit. As soon as the gas pedal is pressed, the valve moves to the open position, and the needle extends. At idle, the valve moves to the closed position at engine speeds above 2100 rpm. The transition to the open position occurs when the engine speed drops below 1900 rpm. Closing and opening the valve allows you to regulate the flow of the fuel-air mixture into the engine and, accordingly, save gasoline consumption in an amount of up to 5%. Also, the principle of operation of the valve allows to reduce the wear of the piston group. The direct effect of the solenoid valve is to reduce emissions of harmful substances (CO) into the atmosphere, which increases the environmental friendliness of the car.

Symptoms of a Malfunctioning Carburetor Solenoid Valve

You can determine the malfunction of the carburetor solenoid valve by several characteristic features:

• the engine regularly stalls at idle;
• the engine stalls when coasting;
• fuel detonation occurs after the ignition is turned off.

It is also possible to determine the instability of the solenoid valve by a drop in engine speed when an additional load is turned on (car radio, headlights, etc.). Thus, the main symptom of a valve malfunction is unstable idling of the engine.

Valve check

Checking the solenoid valve for correct operation can be carried out in three different modes:

• when the engine is idling;
• during engine braking;
• after turning off the ignition.

The general serviceability of the valve can be checked after the ignition is switched on. To do this, you need to increase the engine idle speed to the level of 2100 rpm. After crossing this mark, a characteristic click should be heard, which means that the valve has closed. After that, you can lower the speed, as soon as their number reaches 1900 rpm, a click should be heard again, indicating that the valve has opened.

During engine braking, while the gear remains engaged, the valve should not open even if the engine speed has dropped below 1900 RPM. If a click is heard at this point, the valve is not working properly.

If, after the engine ignition is turned off, detonations and vibrations occur, this means that the valve does not close the idle jet and the fuel mixture enters the engine, which also indicates a malfunction of the solenoid valve.

You can also simply check the valve by disconnecting the power wire with the engine running. Immediately after disconnection, the motor should stall.

You can check the valve and completely disconnect the device from the carburetor. After dismantling the valve, it can be connected to the battery, after which a click should be heard, and the valve needle should be drawn into the device. After turning off the power, a click should be heard again, and the needle should come out.

The problem with the solenoid valve may lie not only in its malfunction, but also in the electronic control unit and in the wires. You can check the performance of the wire using a multimeter (12 V ± 10%).

Checking the operation of the control unit will require connecting the valve to the battery using an additional wire. You also need a control lamp for standard voltage. First you need to disconnect the supply wire from the valve and connect it to the positive terminal of the battery. An additional wire is also connected to the plus of the battery. After that, you need to start the engine, at a cutoff of 900 rpm, the control lamp should light up, after reaching 2100 rpm it should go out. When it drops to 1900 rpm, it will light up again. If these indicators are met, but the engine stalls at idle, then the malfunction is likely in the valve control unit.

Carburetor Solenoid Installation

When replacing the solenoid valve, it must be correctly adjusted so that the incoming air-fuel mixture meets the required parameters. Installation is carried out with the engine running, as this is what will allow you to fine-tune the valve. In the carburetor, the valve is located under the cover air filter, therefore, to dismantle a faulty solenoid valve, you must first remove the air filter cover.

First you need to hand wrap the valve into the carburetor seat and put on a standard wire that connects the valve to the control unit. After that, it is necessary to start the car engine, which will triple and, possibly, try to stall. If the engine still maintains speed, then further screwing the valve into the carburetor is done with a wrench (by 13 or 14, depending on the type of valve). Further installation is carried out in the following way:

• the key is turned 1–2 cm clockwise, after which the wire is removed;
• if the car engine does not stall, then the wire is put on again and the procedure is repeated;
• as soon as the engine stalls after removing the wire, the valve is installed correctly in the carburetor.

The installation of the solenoid valve must be carried out carefully so as not to damage the fuel jet and the seat in the carburetor. During installation, the size of the fuel mixture entering the engine is automatically adjusted, after which triplets and detonations stop. For fine adjustment, you can tighten the "quality" and "quantity" screws on the valve.

If, after several tightenings of the valve and disconnecting the wire, the engine still does not stall, then this means that fuel enters the engine bypassing the solenoid valve and it is necessary to look for a malfunction in the fuel supply system.

Many owners of cars with carbureted engines, after the failure of the solenoid valve, simply block its operation or dismantle it, which solves the problem with the engine that stops stalling at idle. However, such actions are only at first glance the right decision. Blocking the solenoid valve significantly increases fuel consumption (up to 5%), which will cost much more during further operation of the car.

Sit back, we will talk about one of the most mysterious parts of the scooter - the starting enricher. This detail is small, but very important. It is she who helps to start a cold scooter engine without hemorrhoids in any weather. Only thanks to her, the scooter starts easily with a half-kick, and for those who don’t, it means that their hands grow crookedly. Thanks to her, dear, the scooter does not shoot at the muffler like domestic motorcycles, but runs quietly and smoothly at idle. Praise the Japanese for inventing this thing! - I say in all seriousness.

So, what does it mean - launcher concentrator? This is essentially an additional small carburetor, standing parallel to the main one. It is connected to the main carburetor by three channels - air, emulsion and fuel, drilled in its body. Air is taken in before the throttle valve, the emulsion (mixture) is supplied after it, directly into the carburetor outlet pipe. Gasoline is taken from a common float chamber. Thus, with some stretch, the enricher can be considered an independent device. With a stretch, because, nevertheless, it is structurally inseparable from the carburetor.

Now let's look at the drawing.

The carburetor has a small additional fuel chamber 7, which is connected to the main float chamber 8 through the start jet 9. The tube from the chamber 7 leads to the mixing chamber into which air is supplied and from which the air-gasoline mixture enters the engine. In the mixing chamber, damper 6 can move, similar to the throttle valve of a carburetor, only much smaller. Just like in the throttle, in launcher The damper contains a spring-loaded needle that closes the fuel channel when the damper is lowered. When starting a cold engine, the damper is raised (open). At the first engine speed, a vacuum is created in the emulsion channel and the gasoline in chamber 7 is sucked into the engine, causing a strong enrichment of the mixture and facilitating the first flashes in the engine.

After the engine has started, but has not yet warmed up, it needs an enriched mixture. The enricher works at the same time as a parallel carburetor, gasoline enters it through jet 9, mixes with air and enters the engine. When the engine is running, alternating current from its generator is always supplied to the contacts of the ceramic heater 2 of the thermal electrovalve of the start-up system. The heater warms up the drive 3. Obviously, inside it there is a gas or liquid boiling at a low temperature and a piston connected to the rod 4. When the drive is heated, the rod gradually extends by 3-4 mm and drives the damper through the pusher 5. Valve body 1 is wrapped with thermal insulation (polyethylene foam) and closed with a rubber boot.

Thus, the engine warms up along with the thermoelectric valve and the mixture gradually becomes leaner. After 3-5 minutes, the damper closes completely and the degree of enrichment of the mixture on a hot engine is set only by the carburetor idle system. When the engine stops heating the valve, the damper drive cools down and under the action of spring 10 the pusher 5, rod 4 and damper 6 return to their original position, opening the channels for subsequent start-up. Cooling and return to its original position also occurs within a few minutes.

This design of the enricher is used on almost all modern scooters. Older models may use a non-electric heater design, heat is transferred to the actuator through a copper heat-conducting cylinder directly from the engine cylinder. Sometimes, also, there is a manual damper drive through a cable from the handle on the steering wheel (“Choke”).

Now the "diseases" of the system

1. The air passage may be clogged with dirt. At the same time, the mixture is greatly enriched, even after the engine warms up.

2. The jet may be clogged with dirt. He is very thin, and this often happens. Wherein concentrator it works the other way around - it leans the mixture, making it difficult to start.

3. The contact with the "tablet" of the heater is broken. The valve does not heat up and does not close. Engine works all the time on a re-enriched mixture and does not develop the required power. The resistance across the valve contacts is easy to measure and should be in the region of a few ohms.

4. Mustaches broken off