High-pressure test platform for testing leakage of fuel pump valve device

Abstract

A high pressure test platform (10) for testing leaks of a valve arrangement in a component, the high pressure test platform (10) comprising a high pressure test line (11) connected at one end to a source of pressurized test fluid (24) and having at an opposite end a connector (13) for fluidly coupling to a port of the component; wherein the test line (11) further comprises a test chamber (14) having a predetermined volume and a first shut-off valve (18) connected in series from the connector end; wherein the pressure sensor (16) is arranged to determine a pressure of the test line (11) in a test section between the connector (13) and the first shut-off valve (18); wherein the control unit (32) is configured to monitor a pressure in the test section by means of the pressure sensor and to detect a pressure attenuation; characterized in that a first buffer chamber (20) having a predetermined volume is connected in series in the test line (11) between the first shut-off valve (18) and the second shut-off valve (22), thereby separating the buffer chamber (20) from the pressurized test fuel source (24).

Description

Technical Field

[0001] The present invention generally relates to a high - pressure test platform configured to perform a bleed measurement on a valve device, and more specifically, at the outlet valve and / or pressure relief valve of a high - pressure fuel pump. Background Art

[0002] Engine components such as fuel pumps are typically tested at the end of the production line to check the proper sealing of the valves arranged therein.

[0003] A conventional high - pressure fuel pump known, for example, from US10,907,600 is displacement - type and includes a body housing a pumping chamber cooperating with a reciprocating piston. Fuel enters via an electromechanically controlled inlet valve and exits via an outlet valve. A pressure relief valve is arranged in a return path connecting the valve outlet section to the pumping chamber. Such fuel pumps are typically tested at high pressure to detect potential fluid leakage, also known as "bleed", at the outlet valve or pressure relief valve.

[0004] Current high - pressure test platforms typically include a high - pressure test line, one end of which is connected to the outlet port of the fuel pump to be tested and the other end is connected to a pressurized test fluid source. The test section of the test line includes a pressure sensor and a test chamber that can be isolated from the pressurized test fluid source by a shut - off valve. A control unit is configured to monitor the change in pressure in the test section over time. Then, the bleed measurement process involves increasing the pressure in the test section to a predetermined value, closing the shut - off valve, thereby sealing the test section before measuring the change in pressure and temperature in the test section over time to determine the leakage of the valves in the valve device.

[0005] A disadvantage of such high - pressure test platforms is that during the bleed measurement of the valve device, the platform itself is prone to leaking fluid through its shut - off valve. Such platform leakage may be misinterpreted as leakage from the valve device being tested, thus affecting the validity of the measurement.

[0006] Technical Problem

[0007] The object of the present invention is to provide an improved - designed test platform that avoids the above - mentioned disadvantages.

[0008] This object is achieved by the high - pressure test platform according to claim 1. Summary of the Invention

[0009] The present invention provides a high - pressure test platform for testing the leakage of a valve device in a component. This test platform has been developed for bleed measurement of high - pressure fuel pumps, but can generally be applied to bleed tests of components including one or more valve devices in fuel systems of other fluid - conveying components.

[0010] The test platform includes a high-pressure test pipeline which is connected at one end to a pressurized test fluid source and at the opposite end to a connector which is fluidly coupled to a port of the component to be tested.

[0011] A test chamber (having a predetermined volume) and a first shut-off valve are connected in series from the connector end to form a test section. A pressure sensor is arranged to determine the pressure (of the test fluid) in the test section, and a control unit is configured to monitor the change in pressure over time in the test section, i.e., to determine the pressure decay. The pressure drop in the test section can be referred to as bleed-off, which can be expressed as, for example, the pressure drop or the rate of change (decay) of the pressure.

[0012] According to the invention, a buffer chamber having a predetermined volume is connected in series in the test pipeline between the first shut-off valve and the second shut-off valve, separating the buffer chamber from the pressurized test fuel source. Thus, the test pipeline includes a second volume (which is at the same pressure at the start of the test) having a corresponding (second) shut-off valve after the test section coupled to the component under test. Thus, the first shut-off valve is placed between the test chamber and the buffer chamber at high pressure rather than at low pressure. In other words, there is a small pressure difference between the two sides of the first shut-off valve, which allows for a reduction in possible leakage from the test section.

[0013] In an embodiment, the high-pressure test platform further includes a dirt pipeline branching off from the test section, which itself includes a third shut-off valve for being able to discharge contaminated fuel. The dirt pipeline is typically provided for purification purposes.

[0014] In particular, the dirt pipeline may further include a second buffer chamber having a predetermined volume connected between the third shut-off valve and the fourth shut-off valve, separating the second buffer chamber from the test section and the discharge area. The technical advantage of this buffer chamber is to reduce the pressure difference at each side of the fourth shut-off valve, thus preventing / reducing leakage through the valve.

[0015] Preferably, the first buffer chamber and / or the second buffer chamber has a predetermined volume in the range of 100 to 300 cm 3 , especially about 200 cm 3 .

[0016] Preferably, the test chamber has a predetermined volume in the range of 100 to 300 cm 3 , especially about 200 cm 3 .

[0017] The pressurized test fluid source may include a high-pressure pump, a highly pressurized container (with a regulator) and / or a pressure amplifier having a plunger or a piston.

[0018] A high-pressure test platform can be designed to perform various tests on a fuel pump, which typically includes an inlet valve for allowing fuel into the pump, a plunger, a pump chamber in which the volume changes as the plunger moves to increase the pressure of the fuel, and an outlet check valve that releases the fuel contained in the pump chamber once a sufficient pressure is reached. The fuel pump may also include a pressure relief valve disposed in a passage that connects a section downstream of the outlet check valve to the pump chamber. The pressure relief valve is normally closed and is configured to open when the pressure downstream of the OCV exceeds a predetermined critical value. The fuel pump can be a high-pressure fuel pump.

[0019] A temperature sensor can also be arranged to determine the temperature in the test section of the test line between the connector and the first shut-off valve. Then, the data from the temperature sensor can be used to eliminate the noise in the data from the pressure sensor caused by temperature variations (e.g., an unexpected temperature increase that causes an increase in pressure).

[0020] A second pressure sensor can advantageously be arranged to determine the pressure in the buffer section of the test line between the first shut-off valve and the second shut-off valve. The data from the second pressure sensor can then be used to measure the leakage to and from the buffer section and the overall tightness of the test circuit. In fact, the reading of the second pressure sensor can be used to confirm (verify) the reading of the first pressure sensor.

[0021] For example, the control unit can be configured to measure the pressure change in the test section after establishing a test pressure in the system. Monitor the pressure in the test section during a predetermined test time period (e.g., between 20 seconds and 60 seconds). The result of the measurement can be expressed as a pressure drop (the difference between the starting pressure (i.e., the test pressure) and the pressure at the end of the test period). The bleed level can also be expressed as a decay rate, i.e., the change in pressure over time (the duration of the test period).

[0022] In addition, the control unit is advantageously configured to measure / monitor the pressure in the buffer section (between the first and second shut-off valves) to evaluate the leakage in this section. Generally, if the system is liquid-tight, the pressure change in this buffer section should be minimal. A large pressure drop will indicate leakage through the first and / or second shut-off valves. Therefore, the pressure drop (or decay rate) in the buffer section (measured during the test period) can be compared with a predetermined threshold. If the pressure drop (or decay rate) does not exceed this predetermined threshold, it is considered that there is no leakage in the buffer section. Thus, the measured bleed level in the test section can be confirmed.

[0023] According to another aspect, the present invention provides a method for measuring the bleed of a valve device in a component by means of the high-pressure test platform disclosed herein. The method includes:

[0024] - Fluidly connect the component to the connector;

[0025] - Establish a pressure in the test pipeline up to a predetermined test pressure;

[0026] - Close the first and second shut-off valves;

[0027] - Detect the leakage level based on the change of pressure over time in the test section.

[0028] Preferably, the method further includes:

[0029] - In parallel with the leakage detection, monitor the pressure in the buffer section of the test pipeline between the first shut-off valve and the second shut-off valve;

[0030] - If the pressure drop in the buffer section does not exceed a predetermined threshold, confirm the leakage level.

[0031] In an embodiment, the component is a fuel pump including an outlet valve device and a pressure relief valve. In this case, a test pressure of up to 50 bar can be used for the leakage measurement of the outlet valve device; and a test pressure of at least 250 bar can be used for the leakage measurement of the pressure relief valve. Detailed Description

[0032] Figure 1 The schematic diagram of a high-pressure test platform (or system) 10 according to an embodiment of the present invention is shown. The test platform 10 can be designed to perform a series of tests on a high-pressure fuel pump. However, this specification will only focus on the test platform section configured for leakage testing.

[0033] High-pressure fuel pumps are widely used in the automotive industry to perform fuel delivery at specific times and pressure values. The high-pressure fuel pump (labeled 12 in Figure 1 usually includes a main body 12.1, and the volume of the pump chamber 12.2 of the main body changes with the movement of the reciprocating plunger 12.3 to increase the fuel pressure. Fuel is allowed to enter the pump chamber via an inlet valve (IV) 12.4. An outlet valve device 12.5 is arranged to release the fuel once the fuel contained in the pump chamber reaches a sufficient pressure. The outlet valve device usually takes the form of a check valve and is referred to as an outlet check valve (OCV). The fuel pump may also include a pressure relief valve (PRV) arranged in the pump body, which is located in the passage connecting the section downstream of the OCV to the pump chamber. The PRV is a normally closed check valve, which is configured to open if the pressure downstream of the OCV exceeds a predetermined critical value. Therefore, the OCV allows the fluid to flow back into the pump chamber, thus preventing potential dangerous situations. Such a fuel pump is disclosed, for example, in patent US10,907,600.

[0034] In Figure 1The high-pressure test platform 10 schematically shown above includes a high-pressure test pipeline 11, which is connected at one end to a pressurized test fluid source 24 and at the opposite end to a connector 13 for fluid connection to the outlet port of a high-pressure fuel pump 12. The pressurized test fluid source 24 typically may include a pressure amplifier 24 having a plunger or piston for delivering the pressurized test fluid. As is known in the art, the test fluid may be a calibration oil having fluid properties similar to those of fuel.

[0035] The high-pressure test pipeline 11 includes a test chamber 14, a first pressure sensor 16 arranged to determine the pressure within the test chamber 14, a temperature sensor 17 arranged to determine the temperature within the test chamber 14, a first shut-off valve 18, a second pressure sensor 19, a first buffer chamber 20, and a second shut-off valve 22. The test platform 10 also includes a dirt pipeline (for purging) branching off from the test pipeline 11 at the junction between the high-pressure pump 12 and the test chamber 14 to discard contaminated fuel or test fluid from the test platform. The dirt pipeline includes a second buffer chamber 28, one end of the second buffer chamber 28 is connected to a third shut-off valve 26, and the other end is connected to a fourth shut-off valve 30, and the fourth shut-off valve 30 is connected to the test pipeline 11.

[0036] The control unit 32 is configured to monitor the pressure measured by the pressure sensor 16 and evaluate the pressure change in the test section.

[0037] Then, the high-pressure test platform 10 is used to measure the leakage (bleed-off) of the OCV and PRV of the high-pressure fuel pump 12 according to the following steps:

[0038] - Fluidly connect the high-pressure fuel pump 12 to the connector 13 of the high-pressure test pipeline 11;

[0039] - Open the first shut-off valve 18, the second shut-off valve 22, and the fourth shut-off valve 30, and close the third shut-off valve 26;

[0040] - Establish a pressure in the test pipeline 11 and the dirt pipeline until a predetermined test pressure. For example, for testing the OCV, the test pressure can be up to 50 bar. For testing the PRV, a test pressure higher than 250 bar is used.

[0041] - Close the first block valve 18, the second block valve 22, and the fourth block valve 30;

[0042] - Detect the bleed-off level based on the change in pressure over time in the test section detected by the sensor 16.

[0043] Therefore, the technical effects of the first buffer chamber 20 and the second buffer chamber 28 are to reduce the pressure differences at the first shut-off valve 18 and the fourth shut-off valve 30, respectively. As a result, the possibility of the test fluid leaking out of the test section through these valves is reduced, which means that the leakage detected by the pressure sensor 16 is more likely to occur at the OCV and / or PRV of the fuel pump 12.

[0044] The high-pressure test platform 10 may further include another test section having a connector (not shown) for coupling to the high-pressure fuel pump 12 at its inlet, thereby allowing the test platform to perform other tests on the fuel pump on different sections of the test platform or to pressurize the test fluid in the fuel pump during testing. As previously mentioned, only the section of the test platform configured for the bleed test has been discussed and shown in the drawings.

[0045] It should be noted that, for clarity, the connections between the different components of the high-pressure test platform have been represented by lines. In reality, the different components are connected by tubes with a small cross-sectional area (e.g., an inner diameter between 4 mm and 8 mm, particularly about 6 mm). In contrast, the volumes of the test chamber and the two buffer chambers are 200 cm 3 . Thus, most of the volume within the platform is located in the test chamber and the buffer chambers. It should also be noted that, apart from leakage through the platform valves and the pump valves, the platform is constructed to be completely leak-proof, i.e., platform leakage may only occur around the valves.

Claims

1. A high-pressure test platform (10) for testing the leakage of a valve device in a component, the high-pressure test platform (10) comprising a high-pressure test pipeline (11) that is connected at one end to a pressurized test fluid source (24) and has a connector (13) at the opposite end for fluidly coupling to the ports of the component; wherein the test pipeline (11) further comprises a test chamber (14) having a predetermined volume and a first shut-off valve (18) connected in series from the connector end; wherein a pressure sensor (16) is arranged to determine the pressure in a test section of the test pipeline (11) between the connector (13) and the first shut-off valve (18); wherein a control unit (32) is configured to monitor the pressure in the test section via the pressure sensor and detect pressure decay; characterized in that A first buffer chamber (20) having a predetermined volume is connected in series in the test pipeline (11) between a second shut-off valve (22) and the first shut-off valve (18), and the second shut-off valve (22) separates the buffer chamber (20) from the pressurized test fuel source (24).

2. The high-pressure test platform (10) according to claim 1, the high-pressure test platform (10) further comprising a dirt pipeline branching out from the test section, the dirt pipeline comprising a third shut-off valve (26) for discharging contaminated fuel.

3. The high-pressure test platform (10) according to claim 2, wherein The dirt pipeline includes a second buffer chamber (28) having a predetermined volume connected between a fourth shut-off valve (30) and the third shut-off valve (26).

4. The high-pressure test platform (10) according to any one of the preceding claims, wherein The first buffer chamber (20) and the second buffer chamber (28) each have a predetermined volume in the range of 100 to 300 cm 3 , in particular about 200 cm 3 .

5. The high-pressure test platform (10) according to any one of the preceding claims, wherein The test chamber (16) has a predetermined volume in the range of 100 to 300 cm 3 and in particular about 200 cm 3 .

6. The high-pressure test platform (10) according to any one of the preceding claims, wherein The pressurized test fluid source (24) includes a high-pressure pump, a high-pressure container, and / or a pressure amplifier having a plunger or a piston.

7. The high-pressure test platform (10) according to any one of the preceding claims, wherein The component is a fuel pump having: an inlet valve for allowing fuel to enter the pump; a plunger; and a pump chamber, the volume of which changes as the plunger moves to increase the pressure of the fuel. And an outlet check valve for releasing the fuel contained in the pump chamber once the pump chamber reaches a sufficient pressure.

8. The high-pressure test platform (10) according to claim 7, wherein The fuel pump further includes a pressure relief valve downstream of the outlet check valve to release the fuel back into the pump chamber if the downstream pressure exceeds a predetermined critical value.

9. The high-pressure test platform (10) according to claim 7 or 8, wherein The fuel pump is a high-pressure fuel pump (12).

10. The high-pressure test platform (10) according to any one of the preceding claims, wherein A temperature sensor (17) is arranged to determine the temperature in the test section of the test pipeline (11) between the connector (13) and the first shut-off valve (18).

11. The high-pressure test platform (10) according to any one of the preceding claims, wherein A second pressure sensor (19) is arranged to determine the pressure in the buffer section of the test pipeline (11) between the first shut-off valve (18) and the second shut-off valve (22).

12. A method for measuring the leakage of a valve device in a component by means of a high-voltage test platform (10) according to any one of the preceding claims, the method comprising: - Fluidly connect the component to the connector (13); - Establish a pressure in the test pipeline (11) up to a predetermined test pressure; - Close the first shut-off valve (18) and the second shut-off valve (22); - Detect the leakage level based on the change in pressure over time in the test section.

13. The method according to claim 12, the method further comprising: - In parallel with the leakage detection, monitor the pressure in the buffer section of the test pipeline (11) between the first shut-off valve (18) and the second shut-off valve (22); - If the pressure drop in the buffer section does not exceed a predetermined threshold, confirm the leakage level.

14. The method according to claim 12 or 13, wherein The component is a fuel pump including an outlet valve device and a pressure relief valve, and wherein: A leakage measurement is performed on the outlet valve device using a test pressure up to 50 bar; and A leakage measurement is performed on the pressure relief valve using a test pressure of at least 250 bar.

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