RU2768133C1 - Electromechanical piezo nozzle - Google Patents

Abstract

FIELD: engine technology.

SUBSTANCE: invention can be used in fuel supply systems of internal combustion engines (ICE). The essence of the invention consists in the application, in order to adapt the operation of the piezo nozzle to the change in the size of parts due to temperature fluctuations, of a simple electromechanical design containing a stop 22 and a piezo nozzle mounted in the housing on the side of it and a piezo fixator 23 cyclically acting on it, also in the use of a sprayer, the housing 15 of which is mated with the nozzle housing 1 on the principle of tool cones, and the fuel channel enters the cavity of the atomizer needle at an angle excluding stress concentration and cracking of the atomizer housing in this zone. In addition, an easily removable slit filter 12 is used, for which it is made in conjunction with the high-pressure fuel supply fitting 6 and is mated with the nozzle body cavity according to the principle of tool cones.

EFFECT: invention makes it possible to increase manufacturability and reduce the cost of manufacturing a piezo nozzle, as well as to increase the processability of its maintenance in operation.

3 cl, 1 dwg

Description

An electromechanical piezo injector belongs to diesel fuel supply systems and is designed to supply and cut fuel coming from a fuel pump through a high-pressure accumulator into the combustion chamber of a diesel cylinder.

Known piezo injector (1) for supplying and cutting fuel in the combustion chamber of a diesel engine with electro-hydraulic control, consisting of a nozzle body, a sawing machine, a nozzle needle, a displacement multiplier, a piezo drive (Patent RU 2521596 C2 Method for controlling the fuel supply and a fuel supply control device / Baitimer PM , Naumov V.N.).

The advantage of the piezo injector is the good controllability of fuel injection and the law of its supply.

Known piezo injector (2) for supplying and sawing fuel in the combustion chamber of a diesel engine with electromechanical control, consisting of a housing with fuel supply elements, an executive link made in the form of a piezoceramic rod consisting of separate disks, a valve kinematically associated with the executive link (Patent RU 2201522 C2 Nozzle with electric control for internal combustion engine / BK Zuev, AS Batanov).

The advantage of the piezo injector is the speed and good controllability of the fuel injection process.

A piezo injector (3) with electromechanical control is known, containing a valve for dosing the current medium, consisting of a dosing hole surrounded by a seat, a needle with a locking head that controls the dosing hole, which interacts with its seat to open and close the dosing hole, a piezoelectric actuator that acts on the needle to open the dosing hole, and an elastic return element that acts on the needle with its force to close the dosing hole (Patent RU 2626178 C2 Valve for dosing the flowing medium / Sebastian Thomas (DE).

The advantage of the piezo injector is the speed and good controllability of the fuel injection process.

Known piezo injector (4) for supplying and sawing fuel in the combustion chamber of a diesel engine with electro-hydraulic control, consisting of a nozzle body with a cavity made in the form of a glass and a piezo element placed in it, a hydraulic compensator docked with a sprayer with a floating sleeve and containing a pusher piston, a valve piston , as well as a valve, valve spring, valve plate, spacer with a block of throttles, atomizer nut, fuel supply channel and excess fuel outlet channel (BOSCH Common RAIL piezo injectors http//reforsbel.blogspot.com) which contributes to high speed and good controllability of the injection process, as well as the use in the design of the atomizer with a floating bushing (5) that excludes cracking of the atomizer body in the area of the entry of the fuel supply channel into the pocket, as happens in a traditional design atomizer (Mazing M.V., Ter- Mkrtichyan G.G., B Ogachev S.A. Atomizer with a floating sleeve for fuel systems with high injection pressure // Modern problems of science and education. - 2014. No. 5.; URL: http//www.science-education. ru/ru/article/view?id=14941)

Known piezo injector (6) with electromechanical control and direct drive of the atomizer needle, consisting of the atomizer needle, rod, housing, fuel drain, piezo actuator and adjusting screw (A.P. Marchenko, Dr. tech. Sciences, D.V. Meshkov, PhD ., I. V. Rykova, Candidate of Engineering Science TRENDS IN THE DEVELOPMENT OF INJECTORS FOR CAPACITY FUEL SYSTEMS OF TCOMMON RAIL TYPE p. 72)

The advantage of the piezo injector is the speed and good controllability of the fuel injection process and the use in the design of the atomizer with a floating bushing (5) excluding cracking of the atomizer body in the zone of the fuel supply channel entry into the pocket, as happens in a traditional design atomizer with a minimum number and weight of moving parts (Mazing M .V., Ter-Mkrtichyan G.G., Bogachev S.A. Atomizer with a floating sleeve for fuel systems with increased injection pressure // Modern problems of science and education. - 2014. No. 5.; URL: http//www. science-education.ru/ru/article/view?id=14941)

Known diesel injector (7) consisting of a nozzle body, sprayer, Belleville spring, rod, helical spring (patent RU 2480615 C2 Nozzle for diesel / A.S. Bronshtein, Yu.E. Khryashchev).

The advantage of the nozzle is the simplicity of design and manufacturability.

The disadvantages of the piezo nozzle (1) are the complexity of the hydraulic system of the engine and the complexity of the control system for the operation of each nozzle by a system with two external individual valves with piezo actuators and a low pressure hydraulic accumulator, as well as high manufacturing costs.

The disadvantages of the piezo injector (2) are the need to use a special material with a low coefficient of linear expansion and the difficulty of fine-tuning the power reserve of the actuator before opening the valve.

The disadvantages of the piezo injector (3) are the complexity of the design of the metering valve and the impact on the quality of the injector of the lack of compensation for changes in the dimensions of parts due to temperature fluctuations.

The disadvantages of the piezo injector (4) are the complicated way of adapting the operation of the injector to changes in the dimensions of parts during temperature fluctuations and, as a result, the complexity of the design, which requires high precision in the processing of movable joints with a high manufacturing cost, as well as the complexity of servicing the injector in operation due to the difficult extraction of the slotted filter.

The disadvantage of the piezo injector (6) is the lack of a system for compensating for changes in the dimensions of parts during temperature fluctuations, which can be crucial for assessing the quality of its work, taking into account the minimum values of the displacement of the spray needle.

The disadvantage of the injector (7) is the mechanical control of fuel injection and insufficient speed.

As a prototype, a piezo injector for supplying and atomizing fuel in the combustion chamber of a diesel engine with electro-hydraulic control (4) was chosen, as it meets the technical requirements and has proven itself during operation.

The objectives of the invention are to propose a simple design for adapting the operation of the nozzle to changes in the size of parts during temperature fluctuations, instead of a floating bushing atomizer specialized for operation in an electro-hydraulic controlled injector, another atomizer design that excludes, at high fuel pressures, stress concentration and cracking of the atomizer body in the fuel channel entry zone into the atomizer pocket, as is the case with a traditional atomizer, as well as the proposal of an easily removable slotted filter design.

The modern trend of improving the design of the spray apparatus of nozzles is to increase the number of spray holes with a decrease in their diameter. The limiting version of this trend is a narrow annular gap.

The essence of the invention lies in the use, in order to adapt the operation of the piezo injector to changes in the dimensions of parts during temperature fluctuations, a simple electromechanical design containing a stop and a piezo lock cyclically acting on it; cones, and fuel enters the cavity of the atomizer needle through a fuel channel located at an angle that excludes stress concentration and cracking of the atomizer body in this area and connects to the annular groove, as well as replacing a hard-to-remove slotted filter with an easily-removable one.

According to the invention, an electromechanical piezo injector for a diesel engine is proposed, including a body containing two cavities in the form of glasses, one of which has an annular groove and, together with a rod having filter slots, forms a slotted filter, the other cavity is connected to a channel for removing excess fuel and mates with the body atomizer, with the atomizer needle installed in it, as well as with a piezoelectric element and with a stop, while the stop is cyclically acted upon by a piezofixer installed in the piezo injector housing on the side of it.

In one of the options, the atomizer body is mated with the nozzle body according to the principle of instrumental cones, and fuel enters the atomizer needle cavity through a fuel channel located at an angle that excludes stress concentration and cracking of the atomizer body in this area and is connected to the annular groove.

In one of the options, the slotted filter rod is made together with the high-pressure fuel supply fitting, contains fuel channels and, located on its surface, pairs of equidistant fuel-conducting grooves with filtering slots between them and mates with the surface of the cavity in the nozzle body according to the principle of instrumental cones.

In FIG. 1 shows a diagram of a piezo injector assembly.

The piezo injector consists of a body 1 containing two cavities in the form of cups, one of which has an annular groove 2 and, according to the principle of tool cones, is mated with landing belts 3 and 4 of the rod 5, on one side of which a fitting 6 with channels 7 and 8 is made, and on several pairs of equidistant fuel-conducting grooves 9 and 10 of constant depth are located on its surface, with one groove of each pair connected to an annular groove 2, the other goes into a cavity connected to the fuel channel 11, and filter slots 12 are located between the grooves; the other cavity is connected to the channel for removing excess fuel 13, contains an annular groove 14 and, according to the principle of instrumental cones (7), mates with the atomizer body 15, in which the fuel channel 16 is made and the atomizer needle 17 is installed, which can move relative to the atomizer body; a support washer 18, a spring 19, a support washer 20 are installed on the end of the atomizer body 15, through which the force of the spring 19 is transmitted to the shank of the atomizer needle and presses its locking cone to the locking edge of the atomizer body 15; the shank of the atomizer needle interacts with the piezoelectric element 21, which interacts with the stop 22, which is in contact with the piezo lock 23 and the support washer 24, which supports the spring 25 and the support washer 26. The stiffness of the spring 19 is greater than the stiffness of the spring 25. After assembling the piezo injector under the action of the spring 25, the piezoelectric element 21 and the stop 22 contact between themselves and the shank of the sprayer needle 17 without gaps.

Axial basing of the piezo injector in the cylinder head can be performed, for example, on the conical surface of the housing 1. The dismantling of the atomizer body 15 from the body 1 can easily be done by screwing the nut onto the threaded tip 27 of the atomizer body 15 until it stops in the body 1.

The dismantling of the rod 5 from the body 1 can be quickly done by screwing the nut onto the fitting 6 until it stops against the body 1.

The diagram does not show the power supply system, the location of which is advisable to determine during the design.

The piezo injector works as follows. Fuel under high pressure through channels 7 and 8, annular groove 2, groove 9, filter slot 12, groove 10, fuel channel 11, annular groove 14 and fuel channel 16 enters the cavity of the atomizer needle 17, creating pressure on it as from the side of the guide surface , and from the side of the locking cone, giving it balance and the ability to move during operation without much effort. When a control signal is applied to the piezo lock 23, it presses the stop 22 against the wall of the cavity of the nozzle body 1 and fixes it motionlessly. Next, the control signal is applied to the piezoelectric element 21, which compresses the spring 19 and moves the atomizer needle 17, creating an annular gap between it and the atomizer body 15, through which fuel is injected into the combustion chamber. Excess fuel that has leaked through the precision connection of the needle 17 and the body of the atomizer 15 through the channel 13 is discharged into the diesel fuel tank.

The range of movement of the atomizer needle is determined by the number of plates in the piezoelectric element 21, which, for example, can be selected so that the μf-effective flow area of the annular gap is equivalent to the μf-effective flow area of the spray holes of the atomizer nozzle of the prototype. This will provide a throughput equivalent to the prototype injector and require a very small stroke of the atomizer needle 17, which will increase the speed of the nozzle and maintain a high pressure of injected fuel, the amount of which can be controlled by the duration of the atomizer needle lift 17. With a small lift of the atomizer needle, stable operation of the nozzle can be ensured increasing the fineness of fuel filtration. To do this, on the surface of the rod 5 of the slotted filter, which has a diameter and a side surface area larger than that of the prototype nozzle, more grooves 3 and 4 and filter slots 12 can be made. This will increase the total length of the filter slots 12, which, while maintaining the throughput ability of the filter, will reduce their height and increase the fineness of fuel filtration. At the end of the fuel injection, the control signal to the piezoelectric element 21 and the piezolocker 23 is simultaneously stopped. In this case, the spring 19 is unclenched and returns the atomizer needle 17 to its original position, and the piezolocker 23 releases the stop 22, without preventing its movement when the dimensions of the parts change. Then the cycle repeats.

Significant differences from the prototype are: in the application, to adapt the operation of the piezo injector to changes in the size of parts due to temperature fluctuations, a simple electromechanical design containing a stop and installed in the piezo injector body on the side of it and cyclically acting on it piezo lock, in use instead of a spray with a floating sleeve atomizer, the body of which is mated with the nozzle body according to the principle of instrumental cones, and the fuel channel enters the cavity of the atomizer needle at an angle that excludes the concentration of stresses and cracking of the atomizer body in this area and is connected to the annular groove, as well as in replacing the hard-to-remove slotted filter with an easily extractable, for which it is made together with a high-pressure fuel supply fitting and mates with the cavity of the nozzle body according to the principle of instrumental cones.

Thus, the usefulness of the invention consists in increasing the manufacturability and reducing the cost of manufacturing the design of the piezo injector, and in increasing the manufacturability of its maintenance in operation.

Sources of information.

1. Fuel supply control method and fuel supply control device Patent RU 2521696 C2

2. Patent RU 2201522 C2

3. Patent RU 2626178 C2 Valve for dosing the current medium.

4. Piezo injectors BOSCH COMMON RAIL http://reforsbel.blogspot.com

5. Mazing M.V., Ter-Mkrtichyan G.G., Bogachev S.A. Atomizer with a floating sleeve for fuel systems with high injection pressure // Modern problems of science and education. - 2014. No. 5.;

URL: http://www.science-education.ru/ru/article/view?id=14941

6. A.P. Marchenko, Dr. tech. Sciences, D.V. Meshkov, Ph.D., I.V. Rykova, Ph.D. tech. Sciences. TRENDS IN THE DEVELOPMENT OF COMMON RAIL FUEL INJECTORS page 72.

7. Nozzle for diesel. Patent RU 2480615 С2

Claims (3)

1. An electromechanical piezo injector for a diesel engine, including a body containing two cavities in the form of glasses, one of which has an annular groove and, together with a rod having filter slots, forms a slotted filter, the other cavity is connected to a channel for removing excess fuel and mates with the atomizer body with a spray needle installed in it, as well as with a piezoelectric element and with a stop, characterized in that the stop is cyclically acted upon by a piezo-lock installed in the piezo injector body on the side of it. 2. An electromechanical piezo injector according to claim 1, characterized in that the atomizer body is mated with the injector body according to the principle of instrumental cones, and the fuel enters the atomizer needle cavity through a fuel channel located at an angle that excludes stress concentration and cracking of the atomizer body in this area , and connected to the annular groove. 3. An electromechanical piezo injector according to claim 1, characterized in that the slotted filter rod is made together with a high-pressure fuel supply fitting, contains fuel channels and pairs of equidistant fuel-conducting grooves located on its surface with filter slots between them and mates with the surface of the cavity in the nozzle body on the principle of instrumental cones.

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