Hello. I'll trade for diesel.
On my car is Bosch CP4.1 power system with single-plunger injection pump. Accordingly, all fuel equipment: injectors, sensors, injection pump - Bosch'evskaya. The system as a whole is reliable, however, it has its own subtleties.
One of the few problems on motors with this system is floating, or rather, even jumping speed.
It all starts with periodic twitches of the tachometer needle with an amplitude of + - 50 revolutions, then jumps appear on the go, when driving at even or low traction, and they are felt quite specifically, the car twitches. Further - worse, twitching progresses, the amplitude of the speed fluctuations increases, the frequency of manifestations increases.
It looks like this:
The pressure reducing valve installed on the high-pressure fuel pump itself mows. He is responsible for maintaining the desired pressure in the fuel rail, if necessary, cuts off excess amounts of fuel so that only the required amount enters the rail.
The location of the valve on the injection pump
The BOSCH power system and the valve are Boschian, BMW bought these parts with giblets and never produced them itself, this is understandable and a no brainer. However, you can buy 2 options for the part: the original Bosch (number 1462C00991) for about $90, and an even more original original BMW (that is, the same Bosch, but with a touch of bullshit from BMW) for $160 ...
God, which one should you choose?
The sensor was purchased, but it needs space to replace it, so I had to grit my teeth and clean out the garage. You know, that state when you come up, look at the rubble that there was no time to sort out for about half a year, and you think that it’s easier to just burn it all to hell. He has been in this state for the last 4 months and I did not find the strength and time to deal with him. And here is such a reason.
Okay, back to the valve.
Getting to this valve is quite simple:
- you need to remove the charge air pipe from the intercooler to the throttle valve;
- remove the throttle itself;
- after that, the sensor itself becomes easily accessible and can be removed by unscrewing 2 screws.
After replacement the twitch is gone.
Changed the oil, air and fuel filters along the way,
Upon completion of all procedures bled the power system with a computer(since when replacing the sensor and filter, the fuel system is aired).
Peace for everyone)
P.S. I forgot the most important thing: this problem surfaced at once among several drivers, in the process they exchanged views. So the pioneer was Fil-01, who, by trial and error, figured out what the problem was, and determined which of their 3 electronic devices (there is 1 sensor and 2 valves) in the fuel system causes a speed jump. For this, in fact, many thanks!
Issue price: 6 000 ₽ Mileage: 152000 km
With the advent of the system of direct injection of gasoline into the combustion chamber of the cylinder, distributed and metered by the injector, it became necessary to maintain a stable fuel pressure in the system. The designers solved the problem by borrowing the fuel pressure control valve from diesel engines.
The task of the valve is simple: with increased consumption of gasoline, it must reduce the return flow; when the consumption decreases, open the passage for the return of gasoline to the tank.
A small and inconspicuous element of the fuel system in the event of a malfunction can cause disturbances in the stable operation of the engine. Any motorist whose car has one should know how the fuel check valve works, its possible malfunctions and methods for their elimination.
The device and principle of operation of the valve
In order to understand how the fuel valve works, it is appropriate to recall the design and principle of operation of the thermostat, taking into account two differences: instead of coolant, gasoline flows through the device, and the size of the opening of the passage is not affected by temperature, but by the difference in fuel pressure forces on one side and the springs with an arc. Sometimes an additional regulator is the air pressure in the intake manifold.
Externally, the fuel pressure valve is also similar to, but reduced several times. The metal case, consisting of two cylindrical halves, in one part has two nozzles for the inlet and outlet of gasoline, and in the other - for connection with a hose connected to the manifold. Domestically produced cars use valves that are simpler in design, in which the pressure is regulated solely by the resistance of the spring, they have only inlet and outlet pipes.
When idle, when the pump does not supply fuel, the valve disc tightly closes the seat and does not allow fuel to pass through the line back to the tank. With the start of the pump, which turns on when the engine is started, the fuel pressure in the system gradually increases. Part of it is injected into the cylinders by nozzles, and the rest rests against the valve. As soon as the pressure begins to exceed the set value (about 2.5 kg / cm 2), gasoline overcomes the resistance of the valve spring and begins to flow through the tube into the tank.
Some foreign-made cars use air-pumped valves. Under the valve is a chamber, fenced off by a membrane. The cavity of the chamber is connected by a pipeline to the intake manifold. This is done so that the fuel dosage is additionally regulated by air pressure. When the driver presses the gas pedal, the vacuum in the manifold increases, which helps the valve spring to hold gasoline.
The pressure control valve performs another important function. After stopping the engine, this element allows you to keep the system filled with fuel. At any time when starting the engine, the driver can be sure that the fuel lines are filled with gasoline and starting will not cause difficulties.
Valve malfunctions and their characteristic symptoms
Fuel check valve effect: clogging, corrosion, mechanical damage, wear can significantly affect the stability of the engine.
There are three types of breakdowns:
- the valve does not maintain a sufficiently high pressure. As a result of the weakening of the spring or depressurization of the air pipe, the jamming of the valve in the open state, sufficient gasoline pressure is not created in the system, a smaller dosage enters the injectors, which leads to a loss of power, a drop in speed. As a result of the lack of a sufficient amount of gasoline, starting the engine is difficult;
- the valve is closed or does not allow sufficient excess fuel to return to the tank. With increased pressure of gasoline, consumption increases. In the combustion chamber, with an increased amount of gasoline, the fuel mixture is mixed with air in the wrong proportion. Part of the fuel does not burn, which also leads to a loss of power, an increase in the emission of harmful substances into the atmosphere. A characteristic feature is black exhaust smoke;
- the valve “sticks”, that is, its operation is unstable, pressure surges are replaced by drops. In this mode, the motor is unstable, the idling mode is not supported up to a stop, starting is difficult.
Debugg
The fuel check valve is non-repairable. The body halves, by analogy with the thermostat, are not disassembled. In case of any malfunctions in the operation of the valve mechanism, they are eliminated by a complete replacement of the part.
Using any thermal equipment, it is necessary to comply with all safety requirements. This applies to large installations used in production or construction, and small equipment intended for personal use, such as domestic boilers.
Ignoring the recommended safety measures can lead to extremely serious consequences - after all, we are talking about the safety of your life and those around you. That is why the meaning safety valve for a boiler should not be underestimated, this is a very important part of its equipment, which regulates the pressure inside the device. Unfortunately, not everyone knows about its existence, or forget about its importance. Today we will talk about the need this device, about the principles of its operation and its correct operation.
Purpose of the pressure control valve
To ensure that the pressure inside the boiler does not exceed allowable norms, it is necessary to install a safety device to adjust it. What is the reason for the increase in pressure? According to the laws of physics, hot water expands, and accordingly increases in volume. And the boiler is a sealed device, therefore, excess water cannot find a way out, because the drain valves are closed, and it is impossible to drain the water back into the water supply system due to the installed equipment that regulates the flow of water. Thus, hot water may exceed the tensile strength of the device, and then the boiler will explode. To prevent these serious troubles, it is necessary to equip the water heating system with an adjustment valve.
Many will have a question, why put a fuse if it is enough to remove the control check valve from the water supply? In fact, it does work, just for a while. But this option is fundamentally wrong. Given the unstable pressure in the plumbing system, no one is surprised when the water runs in a thin stream, which means that the pressure is very weak.
Attention ! If water does not enter the boiler under pressure, then already heated water may spill into the system. In this case, the heating elements of the boiler will remain dry, and will burn out very soon.
And even this is not the worst. The pressure in the water supply can rise sharply, water will fall on hot heating elements, strong vaporization will increase the pressure inside the boiler, which will inevitably lead to its rupture. Several liters of boiling water and hot steam will escape, which will lead to serious consequences.
Safety valve device
The boiler pressure safety valve device is presented in the form of two parts - the fuse itself, and the check valve. Externally, the design looks like two cylinders of different diameters connected perpendicularly.
Cylinder bigger size contains a check valve, which consists of three elements: seats, springs and plates. The thread on this part of the device will allow you to screw it to the boiler pipe.
The small cylinder is designed similarly to the large one, only the spring in its composition is much stiffer.
Characteristics and types
The safety valves for the boiler are divided into the following capacities:
- for boilers up to 50 liters;
- for boilers up to 200 liters;
- for boilers over 200 liters.
The greater the power of the safety device, the higher its cost, and, accordingly, the larger and more reliably it will regulate pressure. In the case of fuses, it is not worth saving, it is better to choose the more expensive and more reliable option. It is much easier to allocate money for a quality appliance than to subsequently spend a large amount on apartment renovations.
Models are also divided according to the principle of operation, they are:
- straight;
- folding.
The first option is equipped with a vertically moving butterfly valve. In a flap valve, the damper is located above the seat, and the adjustment is carried out by opening it under the action of pressure.
The safety valve according to the type of design and principle of operation can be:
- straight;
- indirect;
- proportional.
The operating pressure for them is determined by the manufacturer, and the bulk is produced with a maximum adjustment limit of up to 25 bar. But they also make samples much more powerful. With operating temperature from 0 to +250С⁰.
When choosing a valve, it must be taken into account that they have different threads and diameters. The type of thread, its pitch, is determined during production, while the diameter is basically standard: 10-30 mm. Sometimes it is indicated in inches.
Safety valve installation
By following the correct installation technology, you can be sure of the stable operation of the safety valve. It is very common for boiler manufacturers to equip their units with control valves during the assembly process. But sometimes the buyer will have to decide for himself which safety valve to choose and how to install it on the boiler. There are some nuances, for example, the Termex water heater can be equipped with a valve only through adapters of a certain diameter.
But there are general rules installation and adjustment of the safety valve for the boiler:
- Before starting installation, determine the direction of water movement in the valve (it is indicated by an arrow on the body).
- The unit is mounted in the supply pipe.
- Installation is carried out on the area between the water heater and the shut-off valve.
- Seal threaded connections with fum tape or linen.
- Tighten the connections without undue force, but at the same time, tightly enough to avoid leaks.
After the work on installing the safety valve for the boiler is completed, you need to supply water and check all connections for leaks. If the connections leak water, adjust - tighten them more. If this also did not bring results, it is necessary to dismantle the safety device and even better seal the threaded connection with a new winding layer.
To check if the valve is working, simply open the drain hole. If the water runs, then everything is in order. But some manufacturers, such as the safety valve for Gorenje boilers, produce their devices in a slightly different design. Therefore, it is necessary to check the ability of pressure regulation according to the manufacturer's instructions.
Valve malfunctions and its adjustment
Only two things can happen to a safety device: either water does not flow from it, or vice versa, it drips very heavily.
To understand the principle of operation of the safety valve, let us clarify that normally, when water is heated, pressure is adjusted, and water is bled off. This can also happen when the boiler is turned off, that is, it does not heat the water. This is due to the fact that the limit of operation of the safety device is lower than the water pressure in the water supply, that is, if the device withstands 6 bar, and the water supply supplies water at a pressure of 7 bar. If water bleeding for this reason occurs frequently, then it is possible to equip the water supply system with a special gearbox. It will be more convenient to install it immediately at the water inlet to an apartment or house. But you can choose a small model and put it directly in front of the boiler to adjust the pressure in it.
Attention ! When choosing a safety valve, keep this feature in mind, and it is better to choose a more powerful valve.
You can check the serviceability of the valve in another way. After turning off the boiler, you need to raise and lower the emergency pressure release lever several times. Water will stop dripping from the boiler safety valve and will drip again when heating starts.
If water continues to flow from the safety valve for the boiler, this may indicate a blockage in the device. The collapsible model must be removed, cleaned and put in place. The non-separable version can only be replaced.
Of course, the constant dripping of water is an unpleasant sight, but it is not dangerous. But if, on the contrary, water does not appear in the pipes when the pressure is increased, then, most likely, the outlet fitting or the safety valve itself is clogged. You need to clean them, or replace if that does not help.
