RU2778592C1 - Method for impulse loading of pluger pairs of hpfp - Google Patents

Abstract

FIELD: high pressure fuel pumps.

SUBSTANCE: method for impulse loading of plunger pairs of high pressure fuel pumps includes alternately supplying and discharging compressed air to the pneumatic drive of the pump. As the hydraulic part of the installation necessary for the implementation of the proposed method, the tested product is used directly - a plunger pair of high pressure fuel pumps. Pneumatic drive piston movement is controlled by pneumatic drive electrovalves, supplying them with an appropriate pulse-width modulated control signal from an electronic control unit, which allows manual and automatic control of the supply of control signals. Constant contact is ensured between the ends of the piston rod of the pneumatic drive and the plunger of the plunger pair of the high-pressure fuel pump by pressing the plunger against the piston rod with a return spring. To move the plunger of the tested plunger pair of high pressure fuel pump on the working stroke, the movement of the piston rod of the pneumatic drive is used, and to move the said plunger in the opposite direction, the force of the return spring of the plunger of the high pressure pump plunger pair is used. Engine oil is used as the process fluid supplied to the cavity of the tested product. The method includes depressurizing the injection line after the completion of the tests. Manual control of pneumatic actuator solenoid valves is used, among other things, for pumping the discharge line and removing air from it.

EFFECT: high pressure fuel pumps improvement.

3 cl

Description

The invention relates to a technology for the production of fuel equipment for internal combustion engines and can be used in autofrettage and testing of Common Rail fuel system components.

The fuel equipment of internal combustion engines includes hydraulic components, the internal cavities of which are loaded with high fuel pressure during operation. This is especially true for components of Common Rail systems, in which during engine operation there is fuel under a pressure of about 160 MPa and above. A striking example is the bushings of the plungers of high-pressure fuel pumps (hereinafter referred to as high-pressure fuel pumps).

The creation of pressure fluctuations of fuel or other liquids used as process liquids in the internal cavities of the plunger bushings during the production of high-pressure fuel pump plunger pairs can be expedient in at least two cases: secondly, during testing - to simulate operational loading.

A known hydraulic test method involves the use of two working media with different physico-chemical characteristics for testing and includes the following steps:

- filling the internal cavity of the tested product with the first working medium,

- creating an initial pressure in the internal cavity of the tested product and then changing the pressure to a predetermined value with the help of pressure amplifiers made in the form of booster cylinders connected to the tested product in parallel;

- shutdown when a predetermined level of pressure in the internal cavity of the product of all booster cylinders, except for one;

- exposure of the tested product under pressure for a specified time interval (US Pat. RU 2649619, publ. 04.04.2018. Bull. No. 10).

According to the known solution, the first working medium used to drive the pressure boosters is hydraulic oil. Water is used as the second working medium used to fill the internal cavity of the product.

After the booster cylinders have reached a predetermined pressure level, the tests are continued at constant pressure. The number of booster cylinders required for the implementation of the known method may be equal to one, but the preferred option is to alternately use a plurality of booster cylinders with successively increasing gains. In addition, each booster cylinder is equipped with a separate double-acting pump for the drive.

The disadvantages of the known solution include:

- the need to use booster cylinders with different gains;

- the need to use separate pumps to drive each booster cylinder;

- the use of water as one of the working media, which creates the risk of corrosion damage to parts or increases the cost of the process due to the need to introduce anti-corrosion additives into the water;

- carrying out tests at constant pressure.

Pneumohydraulic units are widely used in various branches of technology. These include, for example, pneumohydraulic pumps designed to pressurize a cavity or pump a liquid under high pressure. As a rule, a pneumatic hydraulic booster contains a piston and a rod or plunger chamber, of which the first has a larger diameter, and the second has a smaller one, moreover, the role of the plunger is performed by a rod rigidly connected to the piston (Pneumohydraulic drive. [Electronic resource]. URL: https: // xn--80adfdbscmorebdjpezh9nvd.xn--plai/shop/product/pnevmogidravlicheskiy-privodpnevmogidravlicheskiy-privod/ (date of access: 01/06/2022)).

The closest solution in terms of essential features - the prototype of the present invention - are tests using high-pressure hydraulic pumps with a pneumatic drive manufactured by HYDRAULICS International Inc. pressure with pneumatic drive [Electronic resource], URL: https://hiipumps.ru/download/literature/PumpsRus.pdf (Accessed: 01/06/2022)). The plunger of the hydraulic pump required for testing is rigidly connected to the piston of the pneumatic actuator. The source of compressed air for the pneumatic drive is an external source - a pneumatic network. The control system of the pump required for testing the product includes an asymmetrically loaded reversible spool valve and valves.

The movement of the pneumatic actuator piston can be carried out by supplying air both to both cavities - above and below the piston, and by supplying only to the cavity under the piston with the suction stroke provided by a return spring installed in the cavity under the piston.

The known device used in the tests cannot be connected to the electrical network and is intended for one-time and periodic testing of various products under pressure up to 5516 bar.

It is known that the state standard GOST ISO 9000-2011 “Quality management systems. Fundamentals and vocabulary" defines the concept of "efficiency" as "the relationship between the result achieved and the resources used". From this point of view, the need for a separate hydraulic pump to implement the known solution reduces its efficiency.

The disadvantages of the known solution include the impossibility of implementing a program for loading products with a given pulse frequency, the presence of a separate hydraulic pump, which complicates the design, maintenance and increases the cost of the device for testing, as well as the absence of a pressure relief valve from the discharge line after testing is completed.

The technical problem to be solved by the present invention is the development of an effective method of pulsed loading of plunger pairs of injection pumps, which makes it possible to provide a given cyclic change in pressure in the cavities of the loaded products. This will make it possible to harden the bushings of the injection pump plungers due to autofrettage and to test the plunger pairs of the injection pump while simulating real operating conditions.

The solution of the set technical problem is achieved by:

- use as a hydraulic pump in the installation necessary for the implementation of the proposed method, directly tested product - a plunger pair of injection pump;

- control of the movement of the piston of the pneumatic actuator by electrovalves receiving the appropriate signal from the electronic control unit;

- use of two modes - manual and automatic - control of electrovalves of the pneumatic drive;

- use for moving the piston of a pneumatic drive of changing the air pressure in the cavities above and below the piston;

- use for moving the plunger of the tested plunger pair of high pressure fuel pump, used as a hydraulic pump, on the working stroke of moving the piston rod of the pneumatic drive, and for moving the said plunger in the opposite direction - the return spring of the plunger of the high pressure fuel pump plunger pair;

- ensuring constant contact between the ends of the pneumatic drive piston rod and said plunger of the injection pump pair due to the plunger being pressed against the piston rod by a return spring;

- release of pressure from the discharge line after completion of the tests.

A novelty in the proposed method of pulsed loading of plunger pairs of injection pumps is the combination

- use as a hydraulic pump in the installation necessary for the implementation of the proposed method, directly tested product - a plunger pair of injection pump;

- control of the movement of the piston of the pneumatic drive by the electrovalves of the pneumatic drive, receiving the appropriate control signal from the electronic control unit;

- use of two modes - manual and automatic - control of electrovalves of the pneumatic drive;

- use of the manual control mode of the electrovalves of the pneumatic actuator, including for pumping the discharge line and removing air from it;

- use for moving the plunger of the tested plunger pair of high pressure fuel pump, used as a hydraulic pump, on the working stroke of moving the piston rod of the pneumatic drive, and for moving the said plunger in the opposite direction - the return spring of the plunger of the high pressure fuel pump plunger pair;

- ensuring constant contact between the ends of the pneumatic drive piston rod and said plunger of the injection pump pair due to the plunger being pressed against the piston rod by a return spring;

- release of pressure from the discharge line after completion of the tests. The proposed method of impulse loading of plunger pairs of injection pumps

is carried out as follows.

The product under test - a plunger pair - is installed on the stand. At the same time, with the help of adjusting elements, its axial position relative to the pneumatic drive rod is ensured so that the end of the plunger is pressed against the end of the rod by a return spring.

With the help of an electronic control unit, in the manual control mode of the pneumatic drive solenoid valves, from five to seven reciprocating movements of the pneumatic drive piston and the plunger of the injection pump pair used as a hydraulic pump, which are in constant contact with it, are used to pump the discharge line with process fluid and air removal. As a process fluid, the proposed method involves the use of engine oil.

The electronic control unit provides the simultaneous supply of control signals to the electrovalves of the pneumatic drive according to the following scheme:

1) Air inlet into the cavity above the piston, air outlet from the cavity below the piston.

2) Air outlet from the cavity above the piston, air inlet into the cavity below the piston. It is preferable to control electrovalves with pulse-width modulated signals. By changing the duration and frequency of the control signals, it is possible to set the specified loading mode of the product under test. The selected parameters can be stored in the memory of the electronic control unit for future repetition in automatic control mode.

According to the commands (signals) of the electronic control unit, the solenoid valves sequentially open the inlet and outlet of compressed air to the cavities above and below the pneumatic actuator piston.

Plug the outlet fitting of the plunger pair. A pressure sensor connected to the electronic control unit is connected to the discharge line.

With the help of an electronic control unit, the desired mode of supplying control signals to the electrovalves of the pneumatic drive is switched on.

The duration of testing and/or hydropulse hardening is determined by the specified number of loading cycles or the strength of the tested products.

In the event of failure of the test item or any part of the discharge line, the pressure in the discharge line will drop rapidly. The electronic control unit will respond to this by turning off the signals to the pneumatic actuator solenoid valves.

If the specified number of loading cycles is reached without destruction of the tested product or any part of the injection line, the electronic control unit will also turn off the supply of control signals to the pneumatic actuator solenoid valves.

The process will be stopped automatically.

Operate the pressure relief valve from the pressure line (if the test item and all parts of the pressure line remain intact after loading).

If the object of testing and/or hardening was the injection pump plunger pair, which was in direct mechanical contact with the pneumatic drive rod, it is dismantled from the stand and a new plunger pair is installed instead. If the object of testing and / or hardening was also an additional product connected to the said plunger pair through a high-pressure fuel line, this product is dismantled and replaced with a new one.

In the implementation of the proposed method of pulsed loading of plunger pairs of high-pressure fuel pumps to the plunger pair, which is in mechanical contact with the pneumatic drive rod, additional products can be connected through high-pressure fuel lines to be tested or hydro-strengthened. As such products, any hydraulic components of fuel systems can be used, the internal cavities of which are loaded with high fuel pressure during operation, including accumulators, injector housings, atomizer housings, etc.

The technical result of the method of impulse loading of plunger pairs of high pressure fuel pumps proposed as the present invention is to increase the efficiency of testing and hydraulic strengthening of hydraulic components of fuel equipment, increase the safety of work, as well as the ability to perform hardening of fuel equipment components by autofrettling, the ability to perform hydraulic tests at variable pressure, the ability to simulate the operating modes of the fuel equipment component, which can be used when conducting, for example, strength or life tests of components.

Claims (9)

1. The method of impulse loading of plunger pairs of high pressure fuel pumps, including the alternate supply and removal of compressed air to the pneumatic drive of the pump, characterized in that as the hydraulic part of the installation necessary for the implementation of the proposed method, use directly the product under test - a plunger pair of injection pump; the movement of the pneumatic drive piston is controlled by the pneumatic drive electrovalves, by supplying them with an appropriate control signal from the electronic control unit, which allows manual and automatic control of the supply of control signals; ensure constant contact between the ends of the pneumatic drive piston rod and the plunger of the injection pump pair by pressing the plunger against the piston rod with a return spring; to move the plunger of the tested plunger pair of high pressure fuel pump on the working stroke, the movement of the piston rod of the pneumatic drive is used, and to move the said plunger in the opposite direction - the force of the return spring of the plunger of the high pressure pump plunger pair; engine oil is used as the process fluid supplied to the cavity of the tested product; includes depressurization of the discharge line after completion of the test. 2. The method according to p. 1, characterized in that the manual control of the pneumatic actuator solenoid valves is used, among other things, for pumping the discharge line and removing air from it. 3. A method according to any one of the preceding claims, characterized in that a pulse-width modulated signal is applied to the electrovalves of the pneumatic actuator.