RU2302550C2 - Fuel injection system (versions) - Google Patents

Abstract

FIELD: mechanical engineering; internal combustion engines.

SUBSTANCE: proposed fuel injection system for internal combustion engine contains atomizer with input, plunger with drive from cam limiting overplunger space connected with input of atomizer, high-pressure fuel accumulator, control valve installed between overplunger space and high-pressure fuel accumulator and making it possible to communicate, by electric control signal, overplunger space with high-pressure fuel accumulator and disconnect them from each other, and it is provided with electrically-operated control valve of atomizer designed for opening and closing of atomizer, device to build and regulate fuel pressure in high-pressure fuel accumulator, and fuel tank. Versions of fuel injection system are described in invention.

EFFECT: provision of new combination fuel injection system with mechanically driven plunger pump (injector unit) featuring possibilities of fuel injection with high-pressure fuel accumulator.

21 cl, 11 dwg

Description

The present invention relates to a system for injecting fuel into cylinders of internal combustion engines, in particular into cylinders of compression ignition engines.

Almost all currently known fuel injection systems of modern diesel engines can be divided into two functionally different groups: systems with mechanical control and systems with high pressure fuel cells. Most diesel engines of high power for heavy vehicles use a pump-injector with a mechanical drive and electronic control for fuel injection. In diesel engines of low power, fuel injection is mainly used either by fuel injection systems with a mechanical drive connected to the nozzles of plunger pumps, or systems with high pressure fuel cells (TADs), the so-called common rail systems.

Currently, there are several types of pump nozzles with a mechanical drive. All of them can create exceptionally high injection pressures and have a relatively high hydraulic and mechanical efficiency, which is one of the most important advantages of pump nozzles over systems with fuel injection pumps. Another advantage of pump-nozzles with a mechanical drive is their significantly higher durability compared with systems with TAD. Compared to systems with a mechanical drive of pump nozzles, the lower durability of injection systems with TAVDs is mainly due to the constant effect on their elements of the maximum pressure required to inject fuel into the engine cylinders. Another significant advantage of systems with a mechanical drive of pump nozzles is their inherent ability to provide a favorable nature of the change in the fuel feed rate per injection cycle (injection characteristic). The creation of fuel injection systems with a fuel injection pump with the same characteristics is associated with certain difficulties, and therefore, when certain engine operating conditions require a rectangular injection characteristic inherent in such systems, modern pump nozzles with control valves for direct control of the sprayer can also provide such an injection characteristic. This gives the systems of the latter type more flexibility in adjusting the injection characteristics.

On the other hand, injection systems with TAVD have compared with mechanical injection systems with certain advantages. The most significant advantage of such systems when used in heavy-duty vehicles is the almost unlimited ability to control the injection process in time and the possibility of multiple injection. Such capabilities of fuel injection systems with fuel injection pumps are becoming especially important in connection with the introduction of various exhaust gas treatment systems on diesel vehicles and the development of alternative fuel combustion processes, such as HCCI. The use of a cam in mechanically controlled injection systems for driving a plunger pump significantly limits their ability to provide the necessary regulation of the injection process and the possibility of multiple injection. Another advantage of the injection system with TAVD in comparison with injection systems with mechanical control is the ability to reduce parasitic losses of engine power during its operation in the low load range and at idle. When the engine is operating in these modes, the injection system with TAVD allows more accurate control of fuel consumption than injection systems with a mechanical pump drive with a large diameter plunger. In addition, mechanically controlled injection systems create a very high noise level, which can be caused not only by the fuel injection system itself, but also by vibrations that occur in the transmission that transmits the torque needed to drive the plunger. The high level of noise generated by a mechanically controlled fuel injection system is manifested primarily when the engine is idling. The operation of injection systems with TAVD practically does not significantly contribute to the overall noise level generated by the engine in any operating mode.

The basis of the present invention was the task of developing a new, combined fuel injection system with a mechanical drive of a plunger pump (pump nozzle), which would have the functionality of an injection system with TAD. The present invention seeks to develop a fuel injection system that, in some engine operating modes, could selectively operate on the principles of a mechanical control system or on the principles of a system with a fuel injection system and use their respective advantages, and in other modes in which the corresponding disadvantages of one of the systems adversely affect the performance of the engine, can work on the principles of another system.

US Pat. No. 6,247,450 B1 to Jiang describes a fuel injection system having a mechanically-driven pump nozzle with a control valve and a fuel injection pump. In this system, the fuel pressure in the fuel injection pump is regulated at a relatively low pressure level, and the fuel under this pressure is fed into the pump nozzle through a calibrated metering throttle opening, which opens at a certain return point of the pump nozzle plunger and closes at other positions of the plunger. The amount of fuel entering the supraplunger space depends on the pressure in the TAD and the duration of the opening of the throttle hole. During the stroke of the plunger, the throttle aperture closes, and the plunger applies pressure to the fuel located in the above-plunger space, the dimensions of which allow the injection pressure to be created in it. The above-plunger space is connected to the inlet of a conventional atomizer with a spring-loaded shut-off element through a control valve. When the pressure in the superplunger space rises to the required level, this control valve opens, and the fuel displaced by the plunger through the sprayer is injected into the engine cylinder. When closing the valve and the atomizer, the opening of which is closed by the action of the return spring, the fuel injection into the cylinder stops.

In this system, for controlling the injection, the plunger must remain stationary at the upper point of the working stroke and maintain in the supra-plunger space the pressure created in it during the working stroke of the plunger. The throttle bore closed during reverse and forward plunger operation eliminates the possibility of fuel injection during the predominant part of this time. Obviously, in such a system, fuel injection cannot occur at any time, but occurs only at the moment when the plunger is near the top of its working stroke, because even when the control valve is open during passage of the fuel through the throttle aperture and the pressure in the fuel injection pump exceeding the pressure at which the spring opens the nozzle opening, the differential pressure prevents the fuel injection, which must be maintained in the throttle hole to dose the amount of engine injected into the cylinder fuel burner.

In addition to the limited ability to control injection, the system described in US Pat. No. 6,247,450 also has other disadvantages, which include, in particular, an unfavorable characteristic of the injection at the beginning and end of the injection cycle, a limited range of injection pressures, etc.

As an example of another currently known fuel injection system that is related to the present invention, there may be mentioned a fuel injection system with adjustable pressure and duration of injection from Cummins Inc. Various variants of such a system are described in patents US 3544008, US 4092964 and US 5445323. This type of system contains pump nozzles, the fuel to which is supplied from the TAD. In this system, however, the fuel injection pump is not intended for direct injection of fuel into the engine cylinder, but is used for dosed supply of fuel into the supraplunger space, which is displaced through the nozzle during the forward stroke of the plunger. Such systems have limited control over the injection process in time and require the use of a mechanical drive of the plunger pump for each injection.

The main objective of the present invention is to develop a fuel injection system that can selectively operate on the principles of a system with mechanical control or a pump injector drive and on the principles of a system with a fuel injection pump, using their respective advantages, and in other modes during Avoiding the disadvantages inherent in one of the systems can work on the principles of another system.

In a narrower sense, the present invention is to develop a fuel injection system with a wider than the known injection systems with mechanical control of the range of regulation of the duration of the injection, allowing injection of fuel into the engine cylinders at any angular position of the engine shaft, with a wider compared with known systems injection with TADD injection pressure range and wide possibilities for regulating injection characteristics. The system proposed in the invention for reducing engine noise at idle and in the low-load range can operate on the principles of a system with a fuel injection pump, and in modes requiring high injection pressure, it can operate on the principles of a system with mechanical control, which makes it possible to use a relatively simple system design a system with TAVD and increase its durability due to operation at a relatively low maximum pressure. The injection system proposed in the invention, using the principles of operation of both systems, with appropriate control of the moments and duration of power supply to the control valve, allows to obtain not only injection characteristics that are usual for systems with a mechanical drive of pump nozzles and systems with an injection pump, for example, rectangular or triangular injection characteristics, characteristics injection with pre-injection, high-pressure injection and late injection, but also the characteristics of the injection are called "shoe" form.

Another objective of the present invention is to develop a fuel injection system, which in addition to the above features is reliably protected from the occurrence of too high pressure in it.

These problems are solved in the proposed invention, the fuel injection system for an internal combustion engine containing a spray with an inlet, a cam-driven plunger limiting the plunger space connected to the spray inlet, a high pressure fuel accumulator (TAVD), a control valve installed between the plunger space and TAVD and allowing the electrical control signal to connect the above-plunger space with TAVD or to disconnect them from each other, having an electric drive to a spray control valve for opening and closing the spray gun, a device for creating and regulating fuel pressure in a fuel injection pump and a fuel tank.

In preferred embodiments of the invention, a non-return valve is installed between the plunger space and the TAD; the inlet of which is connected to the TAD. The control valve in the third position disconnects the supra-plunger space from the TAVD and connects the supra-plunger space with the drain line, in the second position disconnects the supra-plunger space from the drain line and the TAVD, and in the first position disconnects the supra-plunger space from the drain line and connects the supra-plunger space with the TAVD.

In one of the private embodiments, the device for creating and regulating the fuel pressure in the fuel injection pump contains a variable displacement hydraulic pump and a device for regulating the pump performance and thus creating the necessary pressure in the pressure pump or constant pressure hydraulic pump and a device for controlling the pump speed. In the latter case, the hydraulic pump is driven by the engine starter. The maximum pressure in the TAD can be 600 bar.

In another embodiment, the fuel injection system comprises a nozzle with an inlet and a needle, an elastic link that pushes the needle in the direction in which it closes the nozzle, a spool that is installed in the distribution chamber with an inlet throttle and an outlet and which abuts against the needle, which increases pressure in the distribution chamber under the action of the spool closes the atomizer, a cam-driven plunger restricting the above-plunger space connected to the atomizer inlet, TADD, control valve, p located between the plunger space and the TAD and allowing electric connection to connect the plunger space with the TAD or to disconnect them from each other, a spray control valve (CSD) located between the outlet of the distribution chamber and the drain line and allowing the outlet of the distribution chamber to be connected to the drain line or disconnect them from each other, a device for creating and regulating the fuel pressure in the fuel injection pump and the fuel tank, while the input throttle is connected with supraplunger space or with TAD. The effective areas of the inlet sections of the inlet throttle, the outlet of the distribution chamber and the CSD and the elastic link force are selected so that the opening of the CSD is accompanied by the movement of the needle in the opening direction, and thereby the opening of the sprayer at a pressure at the inlet of the sprayer less than the maximum working pressure in TAVD.

In preferred embodiments of this embodiment, the outlet of the distribution chamber and the spool located therein can be configured such that when the spool is in a position corresponding to the open atomizer, the passage section of the outlet of the distribution chamber is narrowed, thereby limiting the leakage of pressurized fuel through the inlet throttle, outlet and open HPS in the drain line.

In yet another embodiment, the fuel injection system comprises a nozzle with an inlet and a needle, an elastic link that pushes the needle in the direction in which it closes the nozzle, a spool that is installed in the distribution chamber and which abuts the needle, which, under increasing pressure in the distribution chamber, the action of the slide valve closes the spray gun, a cam-driven plunger limiting the supra-plunger space connected to the spray inlet, TAVD, a control valve located between the super-plunger by means of an electric control signal and allowing electric connection to connect the plunger space with the TAD or disconnect them from each other, the control panel, which in the first position disconnects the distribution chamber from the drain line and connects the plunger space with the distribution chamber, and in the second position disconnects the distribution chamber from the plunger space and connects the distribution chamber to the drain line, a device for creating and regulating the fuel pressure in the fuel injection pump and the fuel tank. In this embodiment, when the CSD is in the second position in the TADD, it is possible to create a pressure high enough to overcome the force of the elastic link and open the sprayer.

In the preferred embodiments of this embodiment, the CSD in the first position disconnects the distribution chamber from the drain line and connects the distribution chamber to the TAD, and in the second position disconnects the distribution chamber from the TAD and connects the distribution chamber to the drain line.

Figure 1-9 shows a diagram of several embodiments of the proposed invention, the fuel injection system.

Proposed in the first embodiment of the invention, the fuel injection system shown in Fig. 1 consists of a fuel nozzle 1 with a normally closed atomizer 2 and a control solenoid valve 3 that controls the atomizer (abbreviated to CSD, atomizer control valve) for pumping the device 4 with a mechanical drive containing a plunger 5, a cam 6 interacting with it, and a supraplunger space 7, a return spring 8 and an electromagnetic control valve 9, TAVD 10, connected with a group of nozzles and with a mechanical drive device in the engine (not shown), a device 11 for creating a high pressure in the high pressure fuel pump and maintaining it at the required level, a low pressure drain line 12 and a fuel tank 13. Pressure control in the fuel accumulator 10 and valve control 3 and 9 are carried out not shown in the drawing by the electronic control unit.

Fuel injector 1 operates like a conventional well-known injector used in fuel injection systems with TAD. The nozzle 1, like all nozzles of this type, has a needle 15, which, under the action of a spring pressing it 14, closes the nozzle 2 located in the distribution (spool) chamber 17, the spool 16, which abuts the needle 15 with increasing pressure in the distribution chamber 17 and closes a sprayer, an inlet choke 18 and an outlet 19. An inlet choke 18 connects the distribution chamber 17 to the plunger space 7, and an outlet 19 connects the distribution chamber to the control panel 3. According to the corresponding control signal The regulating solenoid valve connects the outlet 19 of the distribution chamber to the drain line 12. The areas of the inlet section of the inlet throttle, outlet and channels of the control solenoid valve are selected so that when the control solenoid valve opens and the pressure drop in the distribution chamber that accompanies it opens, the conical surface of the pressure needle 15 was sufficient to lift it and thereby open the spray gun 2. As in all of known fuel injection systems with fuel injection pump, the outlet of the distribution chamber 19 and the spool 16 are made in such a way that when the spool is in the position corresponding to the open atomizer 2, it narrows the passage section of the outlet of the distribution chamber, thereby limiting the leakage of pressurized fuel through the inlet the throttle 18, the outlet 19 and the open CSD 3 in the drain line 12.

The above-plunger space 7 is connected to the inlet of the sprayer 2. The control valve 9 controls the connection of the above-plunger space with TAVD 10 and the disconnection of the above-plunger space from TAVD.

Proposed in the invention, the fuel injection system operates as follows. The fuel pressure in TAVD 10 is maintained at a certain constant level depending on the specific mode of engine operation. At a relatively low injection pressure, for example, at idle or when the engine is in the range of relatively small loads, the control valve 9 remains open throughout the entire operating cycle of the engine. With a direct stroke, the plunger 5 displaces the fuel from the supra-plunger space through the open control valve 9 back to the TAVD 10, while the pressure in the supra-plunger space increases slightly at low power consumption necessary to move the plunger. To inject fuel into the engine cylinder, it is necessary to open the CSD 3, at the opening of which the pressure in the distribution chamber 17 and the spool 16 and the needle 15 rise up and open the sprayer. Then, through the open sprayer until the CSD closes, fuel under pressure, which is created in the fuel injection pump, is injected into the engine cylinder. After closing the CSD, the pressure in the distribution chamber increases again to the pressure in the TADD, and the spool 16 loaded with the spring 14 closes the atomizer. This mode of operation of the injection system is hereinafter referred to as the mode of operation from the TAVD. It should be noted that when the injection system is in operation from the TAVD, the difference between the pressure in the TAVD 10 and the pressure in the drain line 12 should be greater than the pressure at which the needle-loaded needle 2 opens and which, as is known, is determined by the preliminary compression of the spring 14 and the size of the conical surface of the closed needle 15.

The operation of the injection system in the mode of operation from the TAVD allows you to reduce the noise level that occurs in fuel injection systems with mechanical control while increasing and sharply reducing the power of the mechanical drive of the plunger pump, in particular the pump nozzle. The use of TAVD provides the possibility of fuel injection at any moment of the engine's operating cycle. The maximum working pressure of the fuel injection pump can be selected, on the one hand, taking into account its cost, service life and a number of other parameters, and on the other hand, taking into account all the advantages of this injection method, such as the possibility of flexible regulation of the injection, reduction of noise level and other parameters, which improve engine performance. Typically, the maximum operating pressure in the TADD is selected in the range from 200 to 600 bar.

If necessary, the injection of fuel under higher pressure during the direct stroke of the plunger 5, the control valve 9 is briefly closed. When closing the control valve 9, the pressure in the superplunger space 7, at the inlet to the throttle 18 and at the inlet to the spray 2 increases. When a certain pressure is reached, the CSD opens, and fuel is injected through the atomizer into the engine cylinder, as discussed above. The end of fuel injection is determined by the time interval between the moment the CSD closes and the moment of opening the control valve 9. This mode of operation of the system is essentially the same as the mode of operation of conventional, well-known injection systems with electronic control and a mechanical drive of unit injectors, which is hereinafter referred to as the EUMF mode . The operation of the fuel injection system according to the invention in the EUMPF mode provides the possibility of fuel injection at very high pressure, characteristic of known systems with pump nozzles and pump units. At the same time, the fuel injection system according to the invention, in which high pressure is generated only in a relatively small space covered by the control valve 9, is devoid of the inherent disadvantages of injection systems with TAVDs, which are caused by very high pressure in both the TAD and other cavities filled with fuel system. In fact, when operating in the EUMF mode, the pressure in the fuel injection pump can be reduced to a very low level of the order of 4-6 bar, sufficient to fill the upper plunger space 7 with fuel during the reverse stroke of the plunger.

The fuel injection system proposed in another embodiment of the invention shown in FIG. 2 differs from that described above by the presence of a non-return valve 20 installed between the inlet of the atomizer 2 and the TAVD 10, the inlet of which is connected to the TAD. The non-return valve 20, which opens during the reverse stroke of the plunger 5, reduces the pressure drop between the supra-plunger space 7 and the TAVD, due to which, in the absence of the non-return valve 20, the pressure is too low for the injection system to operate in the operation mode from the TAVD. In other words, the presence of a check valve 20 in the injection system enables fuel injection during the reverse stroke of the plunger. On the other hand, the availability of

the check valve system allows you to reduce the size of the bore sections of the control valve 9. Reducing the size of the bore sections of the control valve allows you to increase its speed, reduce the size, power consumption, etc.

The principle of controlling the movement of the needle 15 of the spray gun described above may not be suitable if it is necessary to provide a high speed of opening and closing the needle. This problem can be solved using a three-way valve with a corresponding change in the hydraulic circuit. In yet another embodiment of the invention shown in FIGS. 3 and 4, the sprayer needle is controlled by a three-way valve 3 located between the plunger space and the dispensing chamber 17. In this embodiment, the dispensing chamber is connected only to the CSD, to which the dispensing chamber 17 can be connected either as shown in the drawings, with a pressure source, or with a low pressure drain line 12. When the CSD is opened, the distribution chamber is disconnected from the pressure source and connected to the drain line, and a quick drain of fuel from the distribution chamber is accompanied by a quick opening of the needle. When closing the CSD, the distribution chamber 17 is disconnected from the drain line and again connected to a pressure source, the rapid increase of which in the distribution chamber increases the speed of closing the needle.

Similarly to the embodiment shown in FIG. 2, in this embodiment of the invention, it is possible to use the check valve 20 shown in FIG. 4, the inlet of which is connected to the TAD and the outlet to the atomizer 2 and which extends the range of possible temporal control of fuel injection into the cylinder and allows the use of a control valve valve 9 with a smaller maximum flow area.

In yet another embodiment of the invention, shown in FIG. 5, a three-position three-way control valve 9 is used, which is installed between the plunger space 7 and the air duct 10. Using such a control valve 9, the plunger space 7 can be connected to the air duct or drain line 12 or the plunger space can be disconnected from them. Otherwise, this option does not differ from the option shown in figure 3. An advantage of the embodiment shown in FIG. 5 is the possibility of a so-called “bypass” or “drain” of fuel at the end of the injection.

The injection system proposed in this embodiment of the invention begins to operate in the operation mode from the TADD after opening the CSD and depressurizing the distribution chamber 17, as a result of which the atomizer 2 opens.

When the injection system is in operation from the TADV, fuel is supplied to the atomizer from the TAD through an open control valve 9, as shown in Fig. 5. When the injection system in this mode, the control valve 9 is in the first position. When closing the CSD, the pressure in the distribution chamber 17 increases and the sprayer closes. During the direct stroke of the plunger 5, the fuel is displaced into the TAD through the control valve 9, which prevents an excessive increase in pressure in the system and thereby effectively prevents the possibility of cranking and disconnecting the plunger drive mechanism.

During the operation of the injection system proposed in this embodiment of the invention in the EUMF mode, the control valve 9 switches from the first position to the second during the direct stroke of the plunger 5. In the second position, the control valve 9 disconnects the above-plunger space 7 from the TAD and the drain line. When the pressure in the system increases to a certain level and the CSD opens, the needle 15 opens, thereby opening the hole or holes of the atomizer, as described above. When the needle is opened, a certain amount of fuel is injected into the engine cylinder under the action of high pressure of the plunger pump. There are several ways to end fuel injection. Typically, for this purpose, the CSD is closed and the pressure in the distribution chamber 17 is again created. To create counterpressure at the end of the injection, the control valve 9 can be left closed in the second position until the sprayer is completely closed or switched back to the first position. Under the action of high pressure, which is created in the distribution chamber 17, and the efforts of the return spring 14, the needle quickly closes the spray gun. To "bypass" or "drain" the fuel at the end of the injection, the control valve 9 must be switched to the third position, in which the plunger space 7 is connected to the drain line and disconnected from the fuel injection pump. Closing the sprayer needle in this case occurs under the action of the return spring 14 at low fuel pressure in the sprayer.

With the "bypass" of the fuel and the simultaneous creation of back pressure at the end of the injection, the CSD can be directly connected to the TAD, as shown in Fig.6. To complete the injection, the CSD switches to the position in which it disconnects the distribution chamber 17 from the drain line 12 and connects it to the TAD. When the control valve 9 is switched to the third position, the pressure in the plunger space and the nozzle drops, and the needle closes the nozzle under the action of the return spring 14 and the pressure in the distribution chamber 17. In this embodiment of the invention, a relatively weak return spring 14 can be installed in the nozzle and the minimum pressure can be reduced in TAVD, in which the system can operate in the mode of operation from TAVD.

To simplify the fuel injection systems of the invention, the embodiments of which are shown in FIGS. 5 and 6, instead of the three-way valve, as shown in FIGS. 7 and 8, a two-way atomizer control valve can be used. Functionally, the systems shown in FIGS. 7 and 8 are no different from the systems shown in FIGS. 5 and 6. The design and principle of operation of the two-way spray control valve (CSD) were discussed above.

An advantage of the options shown in FIGS. 6 and 8 is a better protection of the system against too high pressure compared to other options. This is due to the fact that in these embodiments, the input of the distribution chamber 17 is connected to the TAD (either directly or through the CSD), and not with the supra-plunger space 7, as in other versions (Figs. 1-5, 7) or in the currently known time like fuel injection systems. In these systems mentioned above, when the CSD fails and, as a consequence, the impossibility of opening it, the depressurization that is created during the direct stroke of the plunger in the supra-plunger space is impossible, since in this case the pressure simultaneously increases both in the atomizer and in the distribution chamber 17 and does not allow the opening of the spray needle. This can result in serious mechanical damage to the injection system and engine. The connection in the options shown in Fig.6 and 8, the distribution chamber 17 with TAVD allows you to constructively limit the maximum pressure that can occur in the nozzle with a closed needle of the sprayer. The maximum maximum pressure in the fuel injection system proposed in these embodiments depends on the preliminary compression of the return spring 14, the diameter of the spool 16 and the pressure in the TADD 10, which can be easily limited by a conventional safety valve.

This method of constructively limiting the maximum pressure can be used in other embodiments of the fuel injection system of the invention. Examples of such systems with constructive limitation of maximum pressure are shown in figa and 9b.

Figure 10 shows another embodiment of the fuel injection system according to the invention, in which for direct regulation of the position of the needle 15 of the atomizer 2, an electric valve 21 for controlling the atomizer is installed in the nozzle. The nozzle 15 of the nozzle can be mechanically connected to the movable armature 22 of the CSD 3. The fuel injection system proposed in this embodiment of the invention can also, as in the above embodiments, operate in the mode of operation from the TAD and / or in the EUMP mode. As an electrically actuated atomizer control valve 21, it is possible to use an electromagnetic valve or, preferably, a piezoelectric valve, which is characterized by high speed and high accuracy of regulation of the position of the needle 15 of the atomizer.

All the above embodiments of the invention allow you to adjust the characteristic of the injection in various ways. When the injection system is operating in the EUMF mode, the needle opening pressure (DPI) can be adjusted by a corresponding delay in the moment of CSD 3 opening relative to the moment of closing of the control valve 9. In the variants shown in FIGS. 6, 8 and 9, to increase the maximum DPI, the spool 16 can be used. whose diameter is greater than the diameter of the needle 15. With an increase in DPI, the injection characteristic approaches rectangular, and with a decrease in DPI, the injection pressure increases gradually and therefore the injection characteristics have a triangular shape.

The present invention also allows you to combine among themselves various modes of multiple injection, such as pre-injection, split injection and injection, which can usually be used in fuel injection systems with EUMF and TAVD. In addition, the system according to the invention makes it possible to obtain a “shoe” shaped injection characteristic with a variable pressure level and a variable phase duration in which the injection characteristic has a “shoe” shape. Obtaining such an injection characteristic is ensured by the operation of the fuel injection system during one injection cycle in the operation mode from the TAD and in the EUMP mode by opening the CSD before the start of the direct stroke of the plunger.

As a device 11 for creating and regulating the fuel pressure in the TAVD 10, a pump with a constant capacity and a pressure regulator made in the form of an adjustable bypass valve can be used. The pump performance is chosen so that the maximum pressure in the fuel injection pump is sufficient to operate the engine in any mode. The pressure in the system can be reduced by using a bypass valve installed at the pump outlet and draining the excess fuel from the pump back to the fuel tank. In another embodiment, for regulating the pressure, a variable displacement pump can be used, the regulation of which allows in any mode of operation of the engine to maintain the pressure in the internal combustion engine at the required level with the bypass valve closed, which in this case performs the functions of a conventional safety valve. Using a variable displacement pump can reduce power losses, but the cost of such pumps is usually higher than the cost of constant displacement pumps. As a device 11 for creating and regulating the fuel pressure in the fuel injection pump, one can also use a conventional pump with constant performance driven by an engine through a mechanical, hydromechanical or electric transmission with a variable gear ratio. In the latter case, not a separate, rather expensive electric motor can be used to drive the pump, but a starter already existing on the motor.

In conclusion, it should be noted that the above preferred embodiments of the invention do not exclude other possible options for its implementation, not beyond its scope defined by the claims.

Claims (23)

1. A fuel injection system for an internal combustion engine, comprising a sprayer (2) with an inlet, a cam-driven plunger (5) limiting the plunger space (7) connected to the sprayer inlet, a high pressure fuel accumulator (10), a control valve (9) installed between the plunger space (7) and the TAD (10) and allowing the electric control signal to connect the plunger space with the TAD or disconnect them from each other, having an electric actuator for controlling the sprayer (21), designated for opening and closing the nebulizer (2), the device (11) for creating and regulating the fuel pressure in the common rail (10) and the fuel tank (13). 2. The fuel injection system according to claim 1, in which a non-return valve (20) is installed between the plunger space (7) and the TAD (10), the inlet of which is connected to the TAD. 3. The fuel injection system according to claim 1, in which the control valve (9) in the third position disconnects the above-plunger space (7) from the TAD (10) and connects the above-plunger space (7) with a drain line (12), in the second position disconnects the above-plunger the space (7) from the drain line (12) and the TAVD (10), and in the first position disconnects the plunger space (7) from the drain line (12) and connects the plunger space (7) with the TAD (10). 4. The fuel injection system according to claim 1, in which the device (11) for creating and regulating the fuel pressure in the fuel injection pump (10) comprises a hydraulic pump of variable capacity and a device for controlling the pump capacity and thereby creating the necessary pressure in the fuel pressure pump. 5. The fuel injection system according to claim 1, in which the device for creating and regulating the fuel pressure in the fuel injection pump (10) contains a hydraulic pump with constant output and a device for controlling the pump speed and thereby creating the necessary pressure in the fuel pump. 6. The fuel injection system according to claim 5, in which the hydraulic pump 5 is driven by the engine starter. 7. The fuel injection system according to claim 4 or 5, in which the maximum pressure in the TAD (10) is 600 bar. 8. A fuel injection system comprising a nozzle (2) with an inlet and a needle (15), an elastic link (14) that presses the needle in the direction in which it closes the nozzle, a spool (16), which is installed in the distribution chamber (17) with an inlet throttle (18) and an outlet (19) and which abuts against a needle (15), which, when the pressure in the distribution chamber (17) increases under the action of the spool (16), closes the atomizer, the plunger (5) driven by a cam, limiting supraplunger space (7) connected to the inlet of the sprayer (2), fuel the first high-pressure accumulator (10) of high pressure (TAVD), a control valve (9) located between the supra-plunger space (7) and the TAVD (10) and that allows the electrical connection of the connecting plunger space to the TAVD or disconnect them from each other, the valve (3 ) sprayer control (CSD), located between the outlet (19) of the distribution chamber (17) and the drain line (12) and allowing you to connect the outlet (19) of the distribution chamber to the drain line or disconnect them from each other, the device (11) for create regulating the pressure of the fuel in the fuel injection pump (10) and the fuel tank (13), while the inlet throttle (18) is connected to the above-plunger space (7) or to the fuel injection pump (10), characterized in that the effective passage areas of the inlet throttle (18), the outlet (19) of the distribution chamber and the CSD (3) and the force of the elastic link (14) are selected so that the opening of the CSD is accompanied by the movement of the needle (15) in the opening direction, and thereby the opening of the atomizer at a pressure at the inlet to the atomizer, less than the maximum working pressure in the TAD. 9. The fuel injection system according to claim 8, in which a check valve (20) is installed between the plunger space (7) and the TAD (10), the inlet of which is connected to the TAD. 10. The fuel injection system according to claim 8, in which the control valve (9) in the third position disconnects the plunger space (7) from the TAD (10) and connects the plunger space (7) with a drain line (12), in the second position disconnects the plunger space (7) from the drain line (12) and TAVD (10), and in the first position disconnects the supra-plunger space (7) from the drain line (12) and connects the supra-plunger space (7) with the TAVD (10). 11. The fuel injection system according to any one of claims 8 to 10, in which the outlet (19) of the distribution chamber and the spool (16) located in it are made in such a way that the spool (16) when it is in the position corresponding to the open atomizer ( 2), narrows the bore of the outlet (19) of the distribution chamber, thereby limiting the leakage of pressurized fuel through the inlet throttle (18), the outlet (19), and the open circuit (3) into the drain line (12). 12. The fuel injection system according to claim 8, in which the device (11) for creating and regulating the fuel pressure in the fuel injection pump (10) comprises a hydraulic pump of variable capacity and a device for controlling the pump capacity and thereby creating the necessary pressure in the fuel pump. 13. The fuel injection system according to claim 8, in which the device for creating and regulating the fuel pressure in the fuel injection pump (10) contains a hydraulic pump with constant output and a device for controlling the pump speed and thereby creating the necessary pressure in the fuel pump. 14. The fuel injection system of claim 8, wherein the hydraulic pump is driven by an engine starter. 15. The fuel injection system according to item 12 or 13, in which the maximum pressure in the TAD (10) is 600 bar. 16. A fuel injection system comprising a nozzle (2) with an inlet and a needle (15), an elastic link (14) that presses the needle in the direction in which it closes the nozzle, a spool (16), which is installed in the distribution chamber (17) and which rests against the needle (15), which, when the pressure in the distribution chamber (17) increases under the action of the spool (16), closes the sprayer, a plunger (5) driven by a cam, limiting the plunger space (7) connected to the sprayer inlet (2) ), high pressure fuel accumulator (10) (TAVD), regul a control valve (9) located between the supra-plunger space (7) and TAVD (10) and which allows to connect the supra-plunger space with the TAVD or disconnect them from each other by an electric control signal, an atomizer control valve (3) in the first position disconnects the distribution chamber (17) from the drain line (12) and connects the plunger space (7) with the distribution chamber (17), and in the second position disconnects the distribution chamber (17) from the plunger space (7) and connects the distribution amer (17) with a drain line (12), a device for creating and regulating the fuel pressure in the fuel injection pump (10) and a fuel tank (13), characterized in that when the CSD (3) is in the second position in the fuel pressure pump (10), you can create the pressure is high enough to overcome the effort of the elastic link (14) and the opening of the atomizer (2). 17. The fuel injection system according to clause 16, in which a non-return valve (20) is installed between the plunger space (7) and the TAD (10), the inlet of which is connected to the TAD. 18. The fuel injection system according to clause 16, in which the control valve (9) in the third position disconnects the above-plunger space (7) from the TAD (10) and connects the above-plunger space (7) with a drain line (12), in the second position disconnects the above-plunger space (7) from the drain line (12) and TAVD (10), and in the first position disconnects the supra-plunger space (7) from the drain line (12) and connects the supra-plunger space (7) with the TAVD (10). 19. The fuel injection system according to any one of paragraphs.16-18, in which the CSD (3) in the first position disconnects the distribution chamber (17) from the drain line (12) and connects the distribution chamber (17) with the TAD (10), and in the second position disconnects the distribution chamber (17) from the TAD (10) and connects the distribution chamber (17) with a drain line (12). 20. The fuel injection system according to clause 16, in which the device (11) for creating and regulating the fuel pressure in the fuel injection pump (10) comprises a hydraulic pump of variable capacity and a device for controlling the pump capacity and thereby creating the necessary pressure in the fuel pump. 21. The fuel injection system according to clause 16, in which the device for creating and regulating the fuel pressure in the fuel injection pump (10) contains a hydraulic pump with constant performance and a device for controlling the pump speed and thereby creating the necessary pressure in the fuel pump. 22. The fuel injection system according to item 21, in which the hydraulic pump is driven by the engine starter. 23. The fuel injection system according to claim 20 or 21, in which the maximum pressure in the TAD (10) is 600 bar.

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