How to test an injection valve

Abstract

A method for testing a check valve (77) of an injection valve (44) for an internal combustion engine. The injection valve includes a sealed chamber (136) having a plunger piston (58) forming a compression chamber (74), a one-way valve (70) for flowing fuel oil to the compression chamber, a check valve, and a nozzle valve (61a). Fuel oil is supplied from the compression chamber to the check valve. The nozzle valve includes a shutoff shaft (62) having a tip (61c) protruding from an opening (61b) of the shutoff shaft. The method includes applying pressure to the tip of the shutoff shaft to maintain the shutoff shaft in a lifted position, supplying plunger oil at a test plunger oil pressure to close the compression chamber, and supplying fuel oil at a test fuel oil pressure to the one-way valve. The test fuel oil pressure is lower than the oil pressure required for the check valve. The method further includes confirming whether the supplied fuel oil leaks from a nozzle valve opening. A method for testing a nozzle valve for leakage is also provided.

Description

[Technical field]

[0001] The subject matter disclosed herein (hereinafter referred to as the present disclosure) relates to a method for testing an injection valve for liquid gas, such as liquefied petroleum gas (LGP).

[0002] WO2016 / 155746 discloses a method for testing an injector for liquid gas such as methanol. The injector can be used in a two-stroke combustion engine. The injector is supplied with a seal oil and a control oil for controlling the supply of the liquid gas. The injector disclosed in this document has a plunger piston chamber for forming a compression chamber, a suction valve having a suction piston, a nozzle valve having a nozzle piston, one or more nozzle openings, and a control oil passage. A fuel flow passage provides a fluid connection from the plunger piston chamber to the nozzle opening when the suction valve is opened by the pressure of the suction piston supplied by the fluid pressure in the plunger piston chamber, and when the nozzle valve is opened by the pressure of the nozzle piston supplied by the pressure of the control oil supplied through the control oil passage. In the test disclosed in WO2016 / 155746, the injector is placed in a holder. The top cover is removed and replaced with a connecting piece. The pressure of the control oil is increased until it reaches the opening pressure of the nozzle valve, and the injector sprays oil from the nozzle opening into a spray chamber. As a result, the nozzle valve opening pressure can be inspected. However, there is no disclosure of a leak test for the suction valve.

[0003] DK202070137A1 and WO2021 / 043380 disclose a method for testing a valve body of a liquefied gas injector and a method for testing an assembled injector. The injector can be used as a fuel boost injector for liquefied petroleum gas (LPG) and may be designed to perform two functions: pressurizing LPG to a desired injection pressure and ensuring that the timing and duration of LPG injection is properly performed.

[0004] During normal operation, the injector is supplied with seal oil, plunger oil, control oil, and liquid petroleum gas (LPG) as fuel. The seal oil is to prevent internal leakage of liquid gas into unintended areas of the injector. The plunger oil is to pressurize the fuel (LPG). The control oil controls when the injector opens to deliver pressurized fuel gas to the combustion chamber. The injector is always supplied with liquid fuel.

[0005] The valve body of the injection valve disclosed in DK202070137A1 and WO2021 / 043380 has a plunger piston chamber for forming a compression chamber, a suction valve having a suction piston, one or more fuel flow passages, a nozzle valve having a nozzle piston, one or more nozzle openings, and a control oil passage. The fuel flow passage provides a fluid connection from the plunger piston chamber to the nozzle opening when the suction valve is opened by the pressure of the suction piston supplied by the fluid pressure in the plunger piston chamber, and when the nozzle valve is opened by the pressure of the nozzle piston supplied by the pressure of the control oil supplied through the control oil passage. The test of the valve body includes a test to confirm that the suction valve is airtight and a test to test that the nozzle valve is airtight.

[0006] A new LPG injector for two-stroke internal combustion engines has been developed by MAN Energy Solutions. This injector is also supplied with sealing oil and control oil to control the supply of liquid gas. If there is a leak, it can be very dangerous.

[0007] Therefore, there is also a need for an improved method for checking for leaks in this new injector, and there is also a need for an improved operational test for this injector.

[0008] It is an object of the present disclosure to provide an improved method for testing an injector for valve leakage.

[0009] According to a first aspect, this object is achieved by providing a method for testing an injector (44) for an internal combustion engine, the injector (44) comprising: a plunger piston sealed chamber (136) having a plunger piston (58) for forming a plunger compression chamber (74), the plunger piston (58) having a plunger piston fuel oil opening (57b) at a bottom thereof, the plunger piston (58) being controlled by the supply of plunger oil through a cover plunger oil supply passage (63), the plunger oil being supplied by plunger oil hydraulic pressure; a suction one-way valve (70) for taking in fuel oil through a suction valve fuel inlet (72), and a plunger chamber supply passage (73) for supplying fuel oil from the suction one-way valve (70) to the plunger compression chamber (74) or to the plunger piston fuel oil opening (57b); a check valve (77) in fluid communication with the plunger compression chamber (74) or the plunger piston fuel oil opening (57b) through a check valve supply passage (75) for supplying fuel oil to the check valve (77); a nozzle valve (61a) including a nozzle valve chamber (81), a nozzle valve piston shutoff shaft (62), a nozzle valve spring (96), a nozzle valve seat (88), and a nozzle valve opening (61b), the nozzle valve piston shutoff shaft (62) having a nozzle valve piston shutoff shaft tip portion (61c) that protrudes through the opening (61b) of the nozzle valve (61a); a plurality of nozzle valve chamber supply passages (78a, 78b, 79a, 79b, 80a, 80b) providing a fluid connection from the check valve (77) to the nozzle valve chamber (81) for supplying fuel oil from the plunger compression chamber (74) or the plunger piston fuel oil opening (57b) through the check valve (77) to the nozzle valve chamber (81); The method comprises: (a) applying a predetermined lift pressure to the nozzle valve piston shutoff shaft tip (61c) protruding through the opening (61b) of the nozzle valve (61a), the lift pressure being higher than a spring force exerted by the nozzle valve spring (96) on the nozzle valve piston shutoff shaft (62), thereby maintaining the nozzle valve piston shutoff shaft (62) in a position lifted from a nozzle valve seat (88) and in a position in which the nozzle valve (61a) is open; (b) the method further includes supplying plunger oil to the plunger piston (58) through the cover plunger oil supply passage (63) at a first test plunger oil oil pressure, the first test plunger oil oil pressure being equal to or greater than a predetermined plunger oil oil pressure required to maintain the plunger piston (58) at the bottom of the plunger piston sealing chamber (136), wherein with the plunger piston (58) maintained at the bottom of the plunger piston sealing chamber (136), the plunger compression chamber (74) is closed but fluid communication is maintained from the plunger chamber supply passage (73) through the plunger piston fuel oil opening (57b) to the check valve supply passage (75); (c) the method further includes supplying fuel oil to the intake valve fuel inlet (72) and through the intake one-way valve (70) and the piston fuel oil opening (57b) to the check valve supply passage (75) at a first predetermined test fuel oil pressure, the first predetermined test fuel oil pressure being lower than a predetermined fuel oil pressure required to open the check valve (77); (d) The method further includes checking whether the supplied fuel oil is leaking from the nozzle valve opening (61b).

[0010] If there is no leakage in the check valve 77, no fuel oil should be observed leaking out of the nozzle valve opening 61b.

[0011] In one example of an implementation form of the first approach, the injector (44) is in an assembled state before testing, and in the assembled state, an atomizer (43) is provided at a lower portion of the injector (44), and the nozzle valve piston shutoff shaft tip (61c) protrudes into the atomizer (43) to output fuel from the nozzle valve opening (61b) through the atomizer (43). When testing the injector (44), the atomizer (43) is removed.

[0012] In one example of an implementation of the first approach, the injection valve (44) under test has a hydraulic piston chamber (155) that holds a hydraulic piston (64) connected to the nozzle valve piston shutoff shaft (62), and the hydraulic piston (64) is controlled by the supply of control oil through control oil supply passages (141, 142) to open and close the nozzle valve (61 a), the control oil being supplied at a certain control oil pressure.

[0013] In one example of an implementation of the first approach, the injection valve (44) under test has seal oil passages (131, 132, 133, 134) that are fluidly connected to the plunger piston sealing chamber (136) to seal the plunger piston (58) and that are fluidly connected to the hydraulic piston chamber (155) to seal the hydraulic piston (64). And the method includes a sealing step, prior to supplying plunger oil in step (b), which includes supplying seal oil at a first seal oil hydraulic pressure to the plunger piston sealing chamber (136) and the hydraulic piston chamber (155) through the seal oil passages (131, 132, 133, 135). Here, the first seal oil hydraulic pressure is a pressure equal to or greater than a predetermined seal oil hydraulic pressure required to seal the plunger piston (58) in the plunger piston sealing chamber (23) and to seal the hydraulic piston (64) in the hydraulic piston chamber (155).

[0014] In one example of an implementation of the first concept, the predetermined seal oil pressure is in the range of 60 to 100 bar, for example, in the range of 70 to 90 bar, for example, around 80 bar.

[0015] In one example of an implementation of the first aspect, the fuel valve (44) to be tested is placed in a functional test valve holder (45); The function test valve holder (45) holds a nozzle valve piston lift unit (46b) having a lift piston (67) and a lift oil passage (66), the nozzle valve piston lift unit (46b) is arranged such that the lift piston (67) engages with the nozzle valve piston shutoff shaft tip portion (61b); Lift oil is supplied to the lift piston (67) through the lift oil passage (68) at a predetermined pressure, thereby providing the predetermined lift pressure for maintaining the nozzle valve piston shutoff shaft (62) in a raised position.

[0016] In one example of an implementation form of the first approach, the nozzle valve piston lift unit (46b) further has a lift unit fuel oil leak path (83, 84) and a lift unit fuel oil outlet (85), the lift unit fuel oil leak path (83, 84) and the lift unit fuel oil outlet (85) being fluidly connected to the nozzle valve opening (61b), whereby fuel oil leaking from the nozzle valve opening (61b) leaks from the lift unit fuel oil outlet (85).

[0017] In one example of an implementation of the first aspect, the lift unit fuel oil outlet (85) faces an oil injector chamber (59) for collecting oil leaking from the lift unit fuel oil outlet (85).

[0018] In one example implementation of the first approach, the hydraulic pressure of the first test plunger is in the range of 280 to 320 bar, for example, approximately 300 bar.

[0019] In one example of an implementation form of the first approach, the step of supplying plunger oil to the plunger piston (58) in step (b) includes a first step of slowly increasing the oil pressure of the supplied plunger oil to a first low initial oil pressure, and a step of increasing the oil pressure to the first test plunger oil oil pressure.

[0020] In one example of an implementation of the first approach, the first low initial oil pressure is in the range of 10 to 50 bar.

[0021] In one example implementation of the first approach, the first predetermined test fuel oil pressure in step (c) is about 30 bar.

[0022] In one example of an implementation form of the first approach, the check valve (77) comprises a check valve housing (87a), a check valve spindle (86), a check valve seat (76), and a check valve spring (87b) for pressing the check valve spindle (86) against the check valve seat (76) to close the check valve (77), and the specified fuel oil pressure required to open the check valve (77) is determined by the spring force of the check valve spring (87b).

[0023] In one example implementation of the first approach, the method includes (e) slowly increasing the supply pressure of fuel oil to the suction valve fuel inlet (72) until the check valve (77) opens.

[0024] In one example of an implementation of the first aspect, the check valve (77) opens when the pressure of the supplied fuel oil overcomes the spring force of the check valve spring (87b).

[0025] In one example implementation of the first approach, the method (f) observes the pressure of the supplied fuel oil when a fuel oil droplet or flow exits the nozzle valve opening (61b) and thereby determines the opening pressure of the check valve (77).

[0026] In one example of an implementation of the first aspect, the method includes (g) releasing the supply pressure of the fuel oil to a pressure sufficiently lower than the determined opening pressure of the check valve (77), for example, to a pressure at least 10 to 20 bar lower or at least 30 bar lower than the determined opening pressure of the check valve (77).

[0027] In one example of an implementation of the first approach, the method includes: (h) increasing the supply pressure of fuel oil to the suction valve fuel inlet (72) until it reaches a pressure that is 3 to 5 bar lower than the determined opening pressure of the check valve (77); (i) checking whether the supplied fuel oil is leaking from the nozzle valve opening (61b); Includes.

[0028] If there is no leakage in the check valve, no fuel oil should come out of the nozzle valve opening 61b.

[0029] In one example implementation of the first approach, fuel oil is supplied by a fuel oil pump (37) in fluid communication with the intake valve fuel inlet, and the oil pressure of the fuel oil is read from a fuel oil pressure gauge (36).

[0030] In one example of an implementation of the first approach, the method includes: (j) stopping the fuel oil pump (37), waiting for about 15 seconds until the fuel oil pressure gauge (36) stabilizes, and observing the fuel oil pressure on the fuel oil pressure gauge (36); (k) waiting approximately 60 seconds and observing the fuel oil pressure on the fuel oil pressure gauge (36); Includes.

[0031] In one example of an implementation of the first approach, the method includes: removing the predetermined lift pressure from the nozzle valve piston shutoff shaft tip portion (61c), thereby pressing the nozzle valve piston shutoff shaft (62) against the nozzle valve seat (88) by the spring force of the nozzle valve spring (96), thereby closing the nozzle valve (61a); supplying fuel oil to the intake valve fuel inlet (72) and through the intake one-way valve (70) and the piston fuel oil opening (57b) to the check valve supply passage (75) at a second predetermined test fuel oil pressure; the second predetermined test fuel oil pressure being higher than the predetermined fuel oil pressure required to open the check valve (77); The method further includes checking whether the supplied fuel oil is leaking from the nozzle valve opening (61b).

[0032] If there is no leakage from the nozzle valve 61a, no fuel oil should come out from the nozzle valve opening 61b.

[0033] In one example implementation of the first approach, the second predetermined test fuel oil pressure is approximately 5 bar higher than the predetermined fuel oil pressure required to open the check valve (77).

[0034] According to a second aspect, there is provided a method for testing an injector (44) for an internal combustion engine. The injector (44) includes: a plunger piston sealed chamber (136) having a plunger piston (58) for forming a plunger compression chamber (74), the plunger piston (58) having a plunger piston fuel oil opening (57b) at a bottom thereof, the plunger piston (58) being controlled by the supply of plunger oil through a cover plunger oil supply passage (63), the plunger oil being supplied by plunger oil hydraulic pressure; a suction one-way valve (70) for taking in fuel oil through a suction valve fuel inlet (72), and a plunger chamber supply passage (73) for supplying fuel oil from the suction one-way valve (70) to the plunger compression chamber (74) or to the plunger piston fuel oil opening (57b); a check valve (77) in fluid communication with the plunger compression chamber (74) or the plunger piston fuel oil opening (57b) through a check valve supply passage (75) for supplying fuel oil to the check valve (77); a nozzle valve (61a) including a nozzle valve chamber (81), a nozzle valve piston shutoff shaft (62), a nozzle valve spring (96), a nozzle valve seat (88), and a nozzle valve opening (61b), the nozzle valve piston shutoff shaft (62) having a nozzle valve piston shutoff shaft tip portion (61c) that protrudes through the opening (61b) of the nozzle valve (61a); a plurality of nozzle valve chamber supply passages (78a, 78b, 79a, 79b, 80a, 80b) providing a fluid connection from the check valve (77) to the nozzle valve chamber (81) for supplying fuel oil from the plunger compression chamber (74) or the plunger piston fuel oil opening (57b) through the check valve (77) to the nozzle valve chamber (81); The method comprises: supplying plunger oil to the plunger piston (58) through the cover plunger oil supply passage (63) at a test plunger oil oil pressure, the test plunger oil oil pressure being equal to or greater than a plunger oil oil pressure required to maintain the plunger piston (58) at the bottom of the plunger piston sealing chamber (136), wherein with the plunger piston (58) maintained at the bottom of the plunger piston sealing chamber (136), the plunger compression chamber (74) is closed but fluid communication is maintained from the plunger chamber supply passage (73) to the check valve supply passage (75) through the plunger piston fuel oil opening (57b); the method further includes supplying fuel oil to the intake valve fuel inlet (72) and through the intake one-way valve (70) and the piston fuel oil opening (57b) to the check valve supply passage (75) at a second predetermined test fuel oil pressure, the second predetermined test fuel oil pressure being higher than a predetermined fuel oil pressure required to open the check valve (77); The method further includes checking whether the supplied fuel oil is leaking from the nozzle valve opening (61b).

[0035] If there is no leakage from the nozzle valve 61a, no fuel oil should come out from the nozzle valve opening 61b.

[0036] In one example implementation of the second approach, the second predetermined test fuel oil pressure is approximately 5 bar higher than the predetermined fuel oil pressure required to open the check valve (77).

[0037] In one example implementation of the second approach, the hydraulic pressure of the test plunger is in the range of 280 to 320 bar, for example about 300 bar.

[0038] According to a third aspect, there is provided a method for testing an injector (44) for an internal combustion engine. The injector (44) includes: a plunger piston sealed chamber (136) having a plunger piston (58) for forming a plunger compression chamber (74), the plunger piston (58) being controlled by a supply of plunger oil through a cover plunger oil supply passage (63), the plunger oil being supplied by a plunger oil hydraulic pressure, the plunger piston (58) further having first and second plunger leak paths (89, 90) providing fluid communication from a bottom portion thereof to an upper sidewall portion; a suction one-way valve (70) for taking in fuel oil through a suction valve fuel inlet (72), and a plunger chamber supply line (73) for supplying fuel oil from said suction one-way valve (70) to said plunger compression chamber (74); a check valve (77) in fluid communication with the plunger compression chamber (74) through a check valve supply passage (75), wherein fuel oil is supplied to the check valve (77) from the plunger compression chamber (74) through the check valve supply passage (75); a nozzle valve (61a) including a nozzle valve chamber (81), a nozzle valve piston shutoff shaft (62), a nozzle valve spring (96), a nozzle valve seat (88), and a nozzle valve opening (61b), the nozzle valve piston shutoff shaft (62) having a nozzle valve piston shutoff shaft tip portion (61c) that protrudes through the opening (61b) of the nozzle valve (61a); a plurality of nozzle valve chamber supply passages (78a, 78b, 79a, 79b, 80a, 80b) providing a fluid connection from the check valve (77) to the nozzle valve chamber (81) for supplying fuel oil from the plunger compression chamber (74) or the plunger piston fuel oil opening (57b) through the check valve (77) to the nozzle valve chamber (81); a third plunger compression leak path (91) providing a fluid connection from the plunger piston sealing chamber (136) to a fuel oil leak port (92) disposed on an exterior surface of the valve; the third plunger compression leak path (91) has an inlet opening facing the plunger piston sealing chamber (136) at a position faced by an outlet opening of the second plunger compression leak path (90) when the plunger piston (58) is in an uppermost position of the plunger piston sealing chamber (136), The method comprises: supplying fuel oil to the suction valve fuel inlet (72) and through the suction one-way valve (70) and the piston fuel oil opening (57b) to the plunger compression chamber at a predetermined leak test fuel oil pressure, the predetermined leak test fuel oil pressure being lower than a predetermined fuel oil pressure required to open the check valve (77) and higher than a fuel oil pressure required to lift the plunger piston (58) to its uppermost position when no plunger oil pressure is applied to the plunger piston (58); The method further includes verifying that the supplied fuel oil is not leaking through the fuel oil leak opening (92).

[0039] Fuel oil can be seen leaking from the fuel oil leak port 92.

[0040] In one example implementation of the third approach, the predetermined leak test fuel oil pressure is in the range of 20 to 40 bar, for example in the range of 25 to 35 bar, for example about 30 bar.

[0041] In one example of an implementation of the third aspect, the plunger piston (58) is not supplied with plunger oil having a plunger oil hydraulic pressure.

[0042] In one example of an implementation of the third approach, the injection valve (44) under test has a hydraulic piston chamber (155) that holds a hydraulic piston (64) connected to the nozzle valve piston shutoff shaft (62), and the hydraulic piston (64) is controlled by the supply of control oil through control oil supply passages (141, 142) to open and close the nozzle valve (61 a), the control oil being supplied at a control oil pressure.

[0043] In one example of an implementation form of the third approach, the injection valve (44) under test has seal oil passages (131, 132, 133, 134) that are fluidly connected to the plunger piston sealing chamber (136) to seal the plunger piston (58) and that are fluidly connected to the hydraulic piston chamber (155) to seal the hydraulic piston (64). The method then includes, prior to supplying fuel oil, a sealing step of supplying seal oil through the seal oil passages (131, 132, 133, 135) to the plunger piston sealing chamber (136) and the hydraulic piston chamber (155) at a first seal oil pressure, where the first seal oil pressure is equal to or greater than a predetermined seal oil pressure required to seal the plunger piston (58) in the plunger piston sealing chamber (23) and to seal the hydraulic piston (64) in the hydraulic piston chamber (155).

[0044] In one example of an implementation of the third concept, the predetermined seal oil pressure is in the range of 60 to 100 bar, for example, in the range of 70 to 90 bar, for example, around 80 bar.

[0045] According to a fourth aspect, there is provided a method for testing an injector (44) for an internal combustion engine. The injector (44) includes: a plunger piston sealed chamber (136) having a plunger piston (58) for forming a plunger compression chamber (74), the plunger piston (58) being controlled by the supply of plunger oil through a cover plunger oil supply passage (63), the plunger oil being supplied by plunger oil hydraulic pressure; a suction one-way valve (70) for taking in fuel oil through a suction valve fuel inlet (72), and a plunger chamber supply line (73) for supplying fuel oil from said suction one-way valve (70) to said plunger compression chamber (74); a check valve (77) in fluid communication with the plunger compression chamber (74) through a check valve supply passage (75), wherein fuel oil is supplied to the check valve (77) from the plunger compression chamber (74) through the check valve supply passage (75); a nozzle valve (61a) including a nozzle valve chamber (81), a nozzle valve piston shutoff shaft (62), a nozzle valve spring (96), a nozzle valve seat (88), and a nozzle valve opening (61b), the nozzle valve piston shutoff shaft (62) having a nozzle valve piston shutoff shaft tip portion (61c) that protrudes through the opening (61b) of the nozzle valve (61a); a plurality of nozzle valve chamber supply passages (78a, 78b, 79a, 79b, 80a, 80b) providing a fluid connection from the check valve (77) to the nozzle valve chamber (81) for supplying fuel oil from the plunger compression chamber (74) or the plunger piston fuel oil opening (57b) through the check valve (77) to the nozzle valve chamber (81); The method comprises: (aa) supplying fuel oil to the suction valve fuel inlet (72) and through the suction one-way valve (70) to the plunger compression chamber (74) at a predetermined nozzle valve test fuel oil pressure that is less than the fuel oil pressure required to open the check valve (77); (bb) supplying plunger oil to the plunger piston (58) through the cover plunger oil supply passage (63) at a first nozzle valve test plunger oil oil pressure that is equal to or greater than the check valve plunger oil oil pressure required to open the check valve (77) and is equal to or less than the nozzle valve plunger oil oil pressure required to overcome the biasing force of the nozzle valve spring (96) and open the nozzle valve (61 a); (cc) checking whether the supplied fuel oil is leaking from the nozzle valve opening (61b); Includes.

[0046] The fuel oil inlet suction one-way valve 70 is a one-way valve, so that fuel oil under pressure can only escape to the nozzle valve chamber 81 through the check valve 77. The nozzle valve 61a must not open, so fuel oil cannot exit from the nozzle valve opening 61b.

[0047] In one example implementation of the fourth approach, the predetermined nozzle valve test fuel oil pressure is equal to or greater than a predetermined fuel oil pressure required to lift the plunger piston (58) to its uppermost position when no plunger oil oil pressure is applied to the plunger piston (58).

[0048] In one example implementation of the fourth approach, the predetermined nozzle valve test fuel oil pressure in step (aa) is in the range of 20 to 40 bar, such as in the range of 25 to 35 bar, for example about 30 bar.

[0049] In one example implementation of the fourth aspect, the initial nozzle valve test plunger oil pressure is in the range of 140 to 160 bar, for example about 150 bar.

[0050] In one example of an implementation of the fourth approach, the injection valve (44) under test has a hydraulic piston chamber (155) that holds a hydraulic piston (64) connected to the nozzle valve piston shutoff shaft (62), and the hydraulic piston (64) is controlled by the supply of control oil through control oil supply passages (141, 142) to open and close the nozzle valve (61 a), the control oil being supplied at a control oil pressure.

[0051] In one example of an implementation form of the fourth approach, the injection valve (44) under test has seal oil passages (131, 132, 133, 134) that are fluidly connected to the plunger piston sealing chamber (136) to seal the plunger piston (58) and that are fluidly connected to the hydraulic piston chamber (155) to seal the hydraulic piston (64). And the method includes, before supplying plunger oil in step (bb) or before supplying fuel oil in step (aa), a sealing step, namely, supplying seal oil at a first seal oil hydraulic pressure to the plunger piston sealing chamber (136) and the hydraulic piston chamber (155) through the seal oil passages (131, 132, 133, 135). Here, the first seal oil hydraulic pressure is a pressure equal to or greater than a predetermined seal oil hydraulic pressure required to seal the plunger piston (58) in the plunger piston sealing chamber (23) and to seal the hydraulic piston (64) in the hydraulic piston chamber (155).

[0052] In one example of an implementation of the fourth concept, the predetermined seal oil pressure is in the range of 60 to 100 bar, for example, in the range of 70 to 90 bar, for example, around 80 bar.

[0053] In one example of an implementation form of the fourth approach, the check valve (77) includes a check valve housing (87a), a check valve spindle (86), a check valve seat (76), and a check valve spring (87b) for biasing the check valve spindle (86) against the check valve seat (76) to close the check valve (77), and the fuel oil pressure required to open the check valve (77) is determined by the spring force of the check valve spring (87b).

[0054] In one example of an implementation of the fourth approach, the method includes: (dd) incrementally increasing the supply of plunger oil to the plunger piston (58) from the initial nozzle valve test plunger oil oil pressure to a final nozzle valve test plunger oil oil pressure, the final nozzle valve test plunger oil oil pressure being greater than a nozzle valve plunger oil oil pressure required to overcome the biasing force of the nozzle valve spring (96) and open the nozzle valve (61 a); (ee) after each step of increasing the supply of plunger oil, checking whether the supplied fuel oil is coming out of said nozzle valve opening (61b); Includes.

[0055] In one example implementation of the fourth aspect, the final nozzle valve test plunger oil pressure is in the range of 175 to 200 bar, for example, approximately 185 bar.

[0056] In one example of an implementation of the fourth approach, the supply of plunger oil is increased in increments of 5 bar.

[0057] In one example of an implementation of the fourth approach, the method includes: (ff) observing the pressure of the fuel oil supplied when a fuel drop or a fuel stream exits the nozzle valve opening (61b) and thereby determining the opening pressure of the nozzle valve (6a).

[0058] In one example of an implementation of the fourth approach, the method includes: (gg) changing the supply of plunger oil to the plunger piston (58) from the final nozzle valve test plunger oil pressure to a close nozzle valve test plunger oil pressure having a value in a range of 5 to 10 bar lower than the determined opening pressure of the nozzle valve (61 a); (hh) checking whether the supplied fuel oil is coming out of the nozzle valve opening (61b); Includes.

[0059] If there is no leakage in the nozzle valve 61a, no fuel oil should be observed.

[0060] The above and other objects are achieved by the features of the independent claims. Further implementations will become apparent from the dependent claims, the detailed description and the drawings. The above and other aspects of the invention will become apparent from the embodiments described below. [Brief description of the drawings]

[0061] Various aspects, embodiments and implementations are described in detail below with reference to example embodiments illustrated in the drawings. [Figure 1] 1 is a diagram of a test system for testing an injection valve arranged in a functional test valve holder according to an exemplary embodiment, the test system comprising respective supply lines for control oil, seal oil, constant oil, lift oil, fuel oil and test gas. [Diagram 2] 1 is an overall view of an assembled injector valve according to an exemplary embodiment; [Diagram 3] 3 is a longitudinal cross-sectional view of the assembled injector valve of FIG. 2 according to an exemplary embodiment. [Figure 4] 4 is a vertical cross-sectional view of the assembled injector of FIG. 3 rotated to a first angle in accordance with an exemplary embodiment; FIG. [Diagram 5] 4 is a vertical cross-sectional view of the assembled injector of FIG. 3 rotated to a second angle in accordance with an exemplary embodiment; FIG. [Figure 6]3 is an enlarged vertical cross-sectional view of the assembled top cover of FIG. 2 according to an exemplary embodiment. [Figure 7] 4 is a longitudinal cross-sectional view of the assembled injector valve of FIG. 3 rotated to a third angle in accordance with an exemplary embodiment. [Figure 8] 3 is a close-up view of a top cover of the assembled injector of FIG. 2, the top cover including an inlet port, according to an exemplary embodiment. [Figure 9] FIG. 4 is an enlarged longitudinal cross-sectional view of a portion of the cross-sectional view of FIG. 3, illustrating the arrangement of an intake one-way valve for fuel intake, a plunger piston compression chamber for fuel compression, and a check valve for compressed fuel delivery, according to an exemplary embodiment. [Figure 10] 10 is an enlarged longitudinal cross-sectional view of a portion of the enlarged cross-sectional view of FIG. 9, showing the check valve of FIG. 9 at a first angle, according to an exemplary embodiment. [Figure 11] Figure 10 is an enlarged longitudinal cross-sectional view of the check valve of Figure 9 at a second angle; Figure 11 is a diagram illustrating the arrangement of a supply passage for supplying compressed fuel to a nozzle valve according to an exemplary embodiment; [Figure 12] FIG. 13 is an enlarged longitudinal cross-sectional view illustrating an arrangement of a further supply passage for supplying compressed fuel to a nozzle valve according to an exemplary embodiment; [Figure 13] 6 is an enlarged longitudinal cross-sectional view of a portion of the cross-sectional view of FIG. 5, illustrating the arrangement of controlled oil supply and drain passages for actuation of a hydraulic piston according to an exemplary embodiment. [Figure 14] 8 is an enlarged longitudinal cross-sectional view of a portion of the cross-sectional view of Figure 7 illustrating the placement of oil leak paths to control and seal oil leakage from a hydraulic piston according to an exemplary embodiment. [Figure 15] 3 is an enlarged longitudinal cross-sectional view of a portion of the assembled injector of FIG. 2, illustrating the placement of an oil leak path for fuel oil leakage from a hydraulic piston according to an exemplary embodiment. [Figure 16] 3 is an enlarged longitudinal cross-sectional view of a portion of the assembled injector of FIG. 2, illustrating the arrangement of oil leak paths for collecting oil leakage from the mid-valve portion and the atomizer portion, according to an exemplary embodiment. [Figure 17] 17 is an enlarged longitudinal cross-sectional view of a portion of the cross-sectional view of FIG. 16, illustrating the placement of leak chambers for collecting leaked oil at the upper and lower surfaces of the mid-valve portion, according to an exemplary embodiment. [Figure 18] 18 is a cross-sectional view of a top portion of the mid-valve section of FIG. 17 illustrating an arrangement of various oil passages with oil seals according to an exemplary embodiment. [Figure 19] 18 is a cross-sectional view of a top portion of the spindle guide housing opposite the underside of the mid-valve portion of FIG. 17, illustrating the arrangement of various oil passages with oil seals, according to an exemplary embodiment. [Figure 20] FIG. 3 is a general view of the injector valve of FIG. 2 with the nut of the atomizer unit and the corresponding atomizer removed according to an exemplary embodiment. [Figure 21] 21 illustrates the injector valve of FIG. 20 placed in a functional test valve holder with a spray chamber and nozzle valve piston lift unit according to an exemplary embodiment. [Figure 22] 22 illustrates the functional test valve holder of FIG. 21 from another angle; FIG. 23 illustrates the arrangement of the fuel oil inlet connecting piece and the lift oil connecting piece according to an exemplary embodiment; [Diagram 23] 21 is an enlarged longitudinal cross-sectional view showing the arrangement of the injector of FIG. 20 relative to a nozzle valve piston lift unit of a functional test valve holder according to an exemplary embodiment. [Figure 24] 23 is an enlarged longitudinal cross-sectional view showing the placement of the injector of FIG. 20 relative to the fuel oil inlet connecting piece of FIG. 22 according to an exemplary embodiment. [Diagram 25] 22 is an enlarged longitudinal cross-sectional view showing the placement of the injector of FIG. 20 relative to a fuel oil leak port provided in a test sleeve of the functional test valve holder of FIG. 21 according to an exemplary embodiment. [Figure 26] 20 is a longitudinal cross-sectional view showing the placement of the injector of FIG. 20 relative to the functional test valve holder of FIG. 21 with a fuel oil drain sleeve for draining fuel oil from a fuel oil leak port to a spray chamber, according to an exemplary embodiment. [Figure 27] 3 illustrates the assembled injector valve of FIG. 2 positioned in a detection test valve holder according to an exemplary embodiment. [Figure 28] 28 is a longitudinal cross-sectional view illustrating the placement of the injector of FIG 2 relative to the detection test valve holder of FIG 27. According to an exemplary embodiment, the detection test valve holder has a test air inlet port and a plurality of test air outlet ports. [Figure 29] 29 is a schematic diagram illustrating a testing setup holding the detection test valve holder and injector of FIG. 28 and connecting the test air outlet port to the detection test liquid chamber in accordance with an exemplary embodiment. Detailed explanation

[0062] The injector according to the preferred embodiment has been designed by MAN Energy Solutions for a two-stroke internal combustion engine, which is a dual fuel engine capable of running on standard heavy fuel oil or liquefied petroleum gas (LGP), such as a mixture of propane and butane.

[0063] This injector can be used as a fuel boost injector for liquefied petroleum gas (LPG) and may be designed to perform two functions: to pressurize the LPG to a desired injection pressure and to ensure proper timing and duration of LPG injection.

[0064] During normal operation, the injector is supplied with seal oil, plunger oil, control oil, constant oil, and liquefied petroleum gas (LPG) as fuel. The seal oil is to prevent internal leakage of liquid gas into unintended areas of the injector. The plunger oil is to pressurize the fuel (LPG). The control oil controls when the injector opens to deliver pressurized fuel gas to the combustion chamber. The injector is always supplied with liquid fuel. When the control oil is supplied, the injector is closed. When the control oil supply is stopped and the plunger oil pressure overcomes the valve opening pressure, the injector opens. The constant oil supply flows in the opposite direction to the control oil supply. When the control oil is supplied, the valve is pressured to close, and when the control oil supply is stopped, the valve opens as there is no pressure to counter the constant oil supply.

[0065] An embodiment of a fully assembled injector valve 44 is described below with reference to FIGS.

[0066] The injector includes a top cover 120, a barrel body 122 having a barrel flange 121, a spindle guide housing 124, an intermediate part 123 between the barrel body 122 and the spindle guide housing 124, a spindle guide coupling nut 127 for coupling the barrel body 122 with the intermediate part 123 and the spindle guide housing 124, and an atomizer coupling nut 126 for holding the atomizer 43 for discharging compressed fuel gas. Please refer to Figures 2 and 3.

[0067] The top cover 120 has a plunger oil inlet port 49b, a control oil inlet port 130, a seal oil inlet port 128, a constant oil inlet port 129, and an air bleed outlet 55. The constant oil inlet port 129 functions as a control oil discharge port during normal operation, but can be used to supply oil at a constant pressure during testing. The top cover 120 further has a cover plunger oil passage 63 in direct fluid communication with the plunger oil inlet port 49b, and cover passages 56a, 56b, 56c in fluid communication with the air bleed outlet 55. Please refer to Figures 3, 4, 5, 6, and 8.

[0068] The barrel body 122 has a plunger piston 58 (see FIGS. 3 and 4) inserted into the plunger piston sealed chamber 136, and a plunger piston head chamber 156. The plunger piston 58 has an upper piston head that moves within the plunger piston head chamber 156. The bottom of the plunger piston 58 faces the plunger compression chamber 74. The bottom of the plunger piston 58 is provided with a plunger piston fuel oil opening 57b. The length of the plunger piston head chamber 156 determines the maximum travel of the plunger piston 58, and thereby determines the minimum size of the compression chamber 74. The pressure of the fuel in the compression chamber 74 is determined by the pressure supplied to the top of the plunger piston 58. The head of the plunger piston 58 is provided with a plunger head seal 187 for sealing the contact point between the head of the plunger piston 58 and the plunger head chamber 156, and the barrel body 122 is provided with a piston chamber seal 188 for sealing the contact point between the plunger piston 58 and the compression chamber 74. Two plunger compression chamber leak paths 89, 90 are provided at the bottom of the plunger piston 58. These can be fluidly connected to a third plunger compression chamber leak path 91 and a fuel oil leak port 92 both provided in the barrel body 122. When the plunger piston 58 is in the upper position, the leak paths 89 and 90 are fluidly connected to the leak path 91 and the fuel oil leak port 92. When plunger oil is supplied to the plunger oil passage 63 through the plunger oil inlet port 49b, the plunger piston 58 is pressed downward, and a plunger oil chamber 57a is formed between the head of the plunger piston 58 and the bottom of the top cover 120 (see FIG. 6).

[0069] The barrel body 122 also has plunger piston head chamber leak paths 148, 149 for discharging plunger oil leaking from a plunger piston head chamber 156 to corresponding oil leak ports 157, 158 (see FIG. 7). The seal oil inlet port 128 is in fluid communication with seal oil passages 131, 132, 133, 134 provided in the barrel body 122, the intermediate piece 123, and the spindle guide housing 124. The seal oil passages are in fluid communication with a plunger piston seal hole 135 for supplying seal oil to a plunger piston seal chamber 136.

[0070] 4 and 9, a suction one-way valve 70 having a suction valve inlet port 72 is shown to be provided in the barrel body 122. The suction valve inlet port 72 and the suction one-way valve 70 supply fuel to a plunger compression chamber 74 through a plunger chamber supply passage 73. Pressurized fuel is directed from the plunger piston compression chamber 74 through a check valve supply passage 75 to a check valve 77. When the plunger piston 58 is at the bottom of the plunger piston compression chamber 74, fuel is supplied from the plunger chamber supply passage 73 to the check valve supply passage 75 through the plunger piston fuel oil opening 57b.

[0071] 10 and 11, the check valve 77 is formed by a check valve housing 87a that holds a check valve spindle 86, and the check valve spindle 86 is pressed toward the check valve seat 76 by a check valve spring 87b. When the pressure from the supplied fuel is greater than the pressure from the spring 87b, the check valve 77 opens, and fuel is supplied from the nozzle valve chamber supply passages 78a, 78b of the barrel body 122 through the nozzle valve chamber supply passages 79a, 79b of the intermediate part 123, through the nozzle valve chamber supply passages 80a, 80b of the spindle guide housing 124, and to the nozzle valve chamber 81 formed in the spindle guide housing.

[0072] A check valve upper chamber 186 is formed around the upper periphery of the check valve housing 87a, and a check valve seal 185 is provided to prevent leakage between the check valve housing 87a and the barrel body 122. A first check valve leak chamber 145 is provided to collect fuel leaking through the seal 185, and the first leak chamber 145 is in fluid communication with a first check valve leak path 144 leading to the fuel oil leak port 92. A second check valve leak chamber 147 in the check valve housing 87a is in fluid communication with the first check valve leak chamber 145 through a second check valve leak path (see Figures 3 and 10).

[0073] The spindle guide housing 124 holds the hydraulic piston 64 in a hydraulic piston bushing 125 (see FIG. 15). The hydraulic piston 64 is connected to a nozzle valve piston guide 95 and further to a nozzle valve piston shutoff shaft 62 forming part of the nozzle valve 61a. The nozzle valve 61a has a nozzle valve spring 96 in the nozzle valve chamber 81. The nozzle valve spring 96 presses the nozzle valve piston shutoff shaft 62 against a nozzle valve seat 88. A nozzle valve lower chamber 82 is formed above the valve seat 88. The nozzle valve piston shutoff shaft 62 has a nozzle valve piston shutoff shaft tip 61c. The nozzle valve piston shutoff shaft tip 61c protrudes from the nozzle valve opening 61b. When no pressure is applied to the hydraulic piston 64 and the pressure from the fuel supplied through the passages 80a, 80b is greater than the pressure from the spring 96, the nozzle valve 61a opens and a flow of fuel is sprayed through the nozzle valve opening 61b and the atomizer 43.

[0074] The pressure applied to the hydraulic piston 64 is determined by the pressure of the control oil supplied. The control oil is supplied from the control oil inlet port 130 through the first control oil supply passage 140 in the barrel body and the second control oil supply passage 141 in the intermediate part 123 to the hydraulic piston operating chamber 65 formed above the hydraulic piston 64. When the supply of the control oil is stopped, the control oil is discharged from the piston operating chamber 65 through the control oil discharge restriction part 143b and the first control oil discharge passage 143a in the intermediate part 123, and further through the second control oil discharge passage in the barrel body 122 to the constant oil inlet port 129 (see Figures 5 and 15).

[0075] To seal the piston 64 within the bushing 125, seal oil is supplied to the hydraulic piston bushing 125 from the seal oil inlet port 128 through the seal oil passage 134 and into the hydraulic piston seal bore 137. The hydraulic piston seal bore 137 is in fluid communication with the hydraulic piston seal passage 138 and a hydraulic piston seal chamber 139 facing the hydraulic piston 64 (see Figures 4 and 14). A hydraulic piston head is provided on the top of the hydraulic piston 64, which moves within the hydraulic piston chamber 155. The hydraulic piston head has a hydraulic piston seal 189 for sealing the hydraulic piston head within the hydraulic piston chamber 155. The lower surface of the middle part 123 has a hydraulic piston actuation chamber seal 184 for sealing the hydraulic piston actuation chamber 65 (see Figure 14).

[0076] As shown in Figures 14 and 15, there are a number of seals, seal chambers and seal passages associated with the hydraulic piston bushing 125, which are also described below. Control oil may leak from the hydraulic piston seal 189 into the hydraulic piston chamber 155 and from there through the hydraulic piston bushing leak path 154 to the hydraulic piston bushing leak chamber 153. Control oil leaking from the leak chamber 153 may flow through the first, second and third control oil and seal oil leak paths 152, 151 and 150 to the oil leak port 158. The hydraulic piston bushing 125 has a first upper hydraulic piston bushing seal 190 to seal against control oil that may flow from the actuation chamber 65 through the seal 189 into the hydraulic piston bushing leak chamber 153. The hydraulic piston bushing 125 also has a second hydraulic piston bushing seal 191 for sealing against seal oil that may flow from the seal bore 137 into the leak chamber 153, and a third hydraulic piston bushing seal 192 for sealing against seal oil that may flow from the seal bore 137 into the nozzle valve bushing leak chamber 161. The nozzle valve bushing leak chamber 161 is fluidly connected to a first fuel oil leak path 162 in the spindle guide housing 124, a second fuel oil leak path 163 in the intermediate piece 123, and a third fuel oil leak path 164 in the barrel body 122. A nozzle valve leak chamber 159 is provided around the connection between the hydraulic piston 64 and the nozzle valve piston guide 95. The nozzle valve leak chamber 159 is connected to the leak chamber 161 through a fourth fuel oil leak path 160, thereby allowing the supplied fuel that leaks from the nozzle valve chamber 81 along the nozzle valve piston guide 95 to flow from the leak chamber 161 to the first fuel oil leak path 164.

[0077] 16 and 17 show further arrangements of the leak chamber and the leak path. The fuel oil supplied from the nozzle valve chamber 81 through the nozzle valve lower chamber 88 and the nozzle valve piston shutoff shaft 62 may leak into the atomizer fuel oil leak chamber 194 between the atomizer 43 and the atomizer coupling nut 126. The fuel oil leaked from the leak chamber 194 passes through the atomizer fuel oil leak path 168, the spindle guide upper leak oil chamber 171 in the spindle guide housing 124, the middle upper leak oil chamber 170 and the middle leak oil recovery passage 169 in the middle part 123, and the upper oil leak path 167 in the barrel body 122, and flows out through the upper oil leak ports 165 and 166 fluidly connected to the upper oil leak path 167. An intermediate outer leak chamber 198 is provided between the intermediate part 123 and the spindle guide connecting nut 127 , and an intermediate leak path 197 connects the leak path 169 and the leak chamber 198 .

[0078] The middle piece 123 has a number of supply and leak paths passing between the barrel body 122 and the spindle guide housing 124. A corresponding number of seals are required to accommodate the number of supply and leak paths. This is shown in Figures 18 and 19, where Figure 18 is a cross-sectional view of the top portion of the middle valve piece 123 and Figure 19 is a cross-sectional view of the top portion of the spindle guide housing 124 that faces the bottom surface of the middle valve piece 123.

[0079] 18, the first intermediate upper seal ring 172 seals the second control oil supply passage 141, the second intermediate upper seal ring 173 seals the first control oil discharge passage 143a, the third intermediate upper seal ring 174 seals the seal oil passage 133, the fourth intermediate upper seal ring 175 seals the second control / seal oil leak passage 151, the fifth intermediate upper seal ring 176 seals the second fuel oil leak passage 163, the sixth intermediate upper seal ring 177 seals the nozzle valve supply passage 79a, and the seventh intermediate upper seal ring 178 seals the nozzle valve supply passage 79b. Between the seal rings 172, 173, 174, 175, 176, 177, and 178, an intermediate upper leak oil chamber 170 for collecting leak oil is provided. The leak oil chamber 170 communicates with the intermediate leak oil recovery passage 169 .

[0080] In FIG. 19, the first spindle guide upper seal ring 179 seals the nozzle valve supply passage 79b, the second spindle guide upper seal ring 180 seals the nozzle valve supply passage 79a, the third spindle guide upper seal ring 181 seals the second fuel oil leak passage 163, the fourth spindle guide upper seal ring 182 seals the second control / seal oil leak passage 151, and the fifth spindle guide upper seal ring 183 seals the seal oil passage 133. Between the seal rings 179, 180, 181, 182, and 183, a spindle guide upper leak oil chamber 171 for collecting leak oil is provided. The leak oil chamber 171 is connected to the intermediate leak oil collection passage 168. The upper surface of the spindle guide housing 124 is also provided with a central opening for connection to the hydraulic piston bushing 125 that holds the hydraulic piston 64.

[0081] A spindle guide coupling nut inner seal ring 199 is provided as a seal between the spindle guide coupling nut 127 and the spindle guide housing 124, and a spindle guide housing seal 201 is provided as a seal between the atomizer coupling nut 126 and the spindle guide housing 124 (see FIG. 16). Furthermore, a spindle guide coupling nut outer seal ring 200 is provided on the outside of the spindle guide coupling nut 127, which is also shown in FIG.

[0082] To perform a functional test of the injector 44 of Figure 2, the atomizer coupling nut 126 and atomizer 43 are removed from the injector as shown in Figure 20. This leaves the spindle guide housing 124 uncovered and the tip of the nozzle valve piston shutoff shaft 62 protruding beyond the end of the spindle guide housing 124. The spindle guide coupling nut 127 is retained. The functional test includes testing of the nozzle valve 77, which requires lifting the nozzle valve piston shutoff shaft 62 off the nozzle valve seat 88 to hold the nozzle valve open.

[0083] When performing a functional test, the injection valve 44 of Figure 20 is attached to the functional test valve holder 45 shown in Figures 21 to 26, and test oil and gas are supplied from the test system 1 of Figure 1.

[0084] The function test valve holder 45 includes a function test top plate 46a, a nozzle valve piston lift unit 46b, a valve holder nut 46c for connecting the function test top plate 46a and the lift unit 46b, a function test sleeve 46e, and an oil injection chamber 59 below the lift unit 46b. A drain hose hole 60 passes through the lift unit 46b and leads to the drain hose chamber 59. The function test valve connection nut 46d holds the injector 44 of FIG. 20 in place during the function test. The function test sleeve 46e is sized to properly fit the barrel body 122 of the injector 44 and has a fuel inlet passage 71 facing the suction valve inlet port 72 of the barrel body 122. A fuel oil connecting piece 47 is connected to the fuel oil inlet passage 71 for introducing fuel oil. A function test sleeve fuel oil leak port 93 is provided in the function test sleeve 46e. The functional test sleeve fuel oil leak port 93 faces the fuel oil leak port 92 of the barrel body 122. A fuel oil drain sleeve 94 is connected to the fuel oil leak port 93. The fuel oil drain sleeve 94 can reach the drain hose chamber 59 through the drain hose hole 60.

[0085] 1, the plunger oil inlet port 49b is connected to the plunger oil connecting piece 49a, the control oil inlet port 130 is connected to the control oil connecting piece 50, the seal oil inlet port 128 is connected to the seal oil connecting piece 51, and the constant oil inlet port 129 is connected to the constant oil connecting piece 52. The air bleed stop valve 53 is provided at the air bleed port 55. The air bleed stop valve 53 is connected to the air bleed drain hose 54. In the preliminary deaeration process, the air bleed stop valve 53 is opened, and the air bleed drain hose 54 is led to the oil injector chamber 59 through the drain hose hole 60.

[0086] The nozzle valve piston lift unit 46b has a lift oil passage 66 for receiving the supply of lift oil from the test system 1. The lift oil passage 66 is connected to the lift oil connecting piece 48. The central part of the lift unit 46b is formed to a size that fits closely to the protruding tip of the nozzle valve piston shutoff shaft 62 when inserted into the function test valve holder 45, and a lift piston 67 for lifting the nozzle valve piston shutoff shaft 62 when lift oil is supplied to the lift oil passage 66 is arranged in the lift unit 46b. Here, the lift length of the nozzle valve piston shutoff shaft 62 is illustrated as a piston push-up distance 68. Fuel oil may leak into the lift unit fuel oil leak paths 83 and 84 along the lifted nozzle valve piston shutoff shaft 62. The leaked fuel oil is discharged to the oil injection chamber 59 through the lift unit fuel oil outlet 85.

[0087] The fully assembled injector valve 44 of FIG. 2 is subjected to a leak detection test. In performing the leak detection test, the injector valve 44 is placed in the detection valve holder 97a and supplied with 7 bar of air to detect any leaks. To fluidly isolate the various exterior portions of the valve 44 during the leak detection test, first, second, third, fourth and fifth barrel body outer seal rings 205, 206, 207, 208 and 209 are provided on the exterior portions of the barrel body 122, as shown in FIG.

[0088] 27, 28 and 29, the detection valve holder 97a has a detection test sleeve 97b, a detection test top plate 97c and a detection test bottom plate 97d. The detection test bottom plate 97d has a central opening sized to fit the atomizer 43 of the assembled injector 44 so that the atomizer protrudes from the bottom plate 97d into a bottom air outlet chamber 204. The bottom air outlet chamber 204 has a detection test sleeve (DTS), a bottom air outlet port 114 and a detection test fluid drain valve 108.

[0089] When the fully assembled injector 44 is placed in the detection valve holder 97a, the injector 44 holds the plunger oil connecting piece 49a, the control oil connecting piece 50, the seal oil connecting piece 51, and the constant oil connecting piece 52. The air bleed port 55 is provided with an air bleed stop valve 53. This air bleed stop valve 53 is closed during a leak detection test. A plunger oil plug 115 is inserted into the plunger oil connecting piece 49a.

[0090] The detection test sleeve 97b is sized to fit the barrel body outer seal rings 205, 206, 207, 208, 209, thereby forming a number of air inlet and outlet chambers. The detection test sleeve 97b further holds a number of air inlet and outlet ports, as described below, as shown in FIG. 28. The detection test sleeve DTS air inlet port 107 and the detection test sleeve DTS air inlet passage 195 are connected to the detection test sleeve DTS air inlet chamber 196 and are sealed by seal rings 200 and 209. The detection test sleeve DTS lower air outlet port 110 faces the detection test sleeve DTS lower air outlet chamber 203 and is sealed by seal ring 200. The detection test sleeve DTS barrel body air outlet port I (111) faces the detection test sleeve DTS barrel body outlet chamber I (210) and is sealed by seal rings 209 and 208. Detection Test Sleeve DTS Barrel Body Air Outlet Port II (113) faces Detection Test Sleeve DTS Barrel Body Outlet Chamber II (211) and is sealed by seal rings 206 and 205. Detection Test Sleeve DTS Barrel Body Air Outlet Port III (112) faces the fuel oil leak port 92 in the barrel body 122 and is sealed by seal rings 208 and 207. Detection Test Sleeve DTS Barrel Body Air Outlet Port III (112) is sealed by seal rings 207 and 206.

[0091] A detection test liquid chamber 106 for holding liquid is provided. Also, a plurality of detection test hoses, each connected to an air outlet port and a connecting piece, terminate in the liquid chamber 106 so that air leakage can be detected by air bubbles in the liquid chamber 106. The detection test hose 98 is connected to the control oil connecting piece 50, the detection test hose 99 is connected to the seal oil connecting piece 51, the detection test hose 100 is connected to the constant oil connecting piece 52, the detection test hose 101 is connected to the DTS barrel body air outlet port II (113), the detection test hose 102 is connected to the DTS barrel body air outlet port III (112), the detection test hose 103 is connected to the DTS barrel body air outlet port I (111), the detection test hose 104 is connected to the DTS lower air outlet port 110, and the detection test hose 105 is connected to the DTS lower air outlet port 114. Each detection test hose has a check valve 109.

[0092] FIG. 1 shows a test system 1 used to perform a functional test of the injector valve 44 of FIG.

[0093] The test system 1 comprises a gas inlet 1a, an air inlet 1b, a gas outlet 1c, a control oil outlet 1d, a seal oil outlet 1e, a fuel oil outlet 1f, a plunger oil outlet 1g, a lift oil outlet 1h, and a constant oil outlet 1i. Air is supplied from the air inlet 1b at a pressure in the range of 7-10 bar. This pressurized air is used as an input to the hydraulic control valves (plunger oil hydraulic control valve 12, lift oil hydraulic control valve 28, control oil / seal oil hydraulic control valve 8, and fuel oil hydraulic control valve 33). The gas inlet 1a is provided for injecting a test gas in the form of nitrogen at a pressure in the range of 80-300 bar. The pressurized nitrogen is supplied to the nitrogen booster 20 through the nitrogen inlet check valve 22 and subsequently from the nitrogen booster 20 to the gas stop valve 24. A nitrogen gas pressure control valve 23 is provided to control the pressure of the gas output from the gas stop valve 24 to the gas outlet 1c.

[0094] To provide test fluid in the form of hydraulic oil, an oil tank 16 is provided for holding hydraulic oil. The hydraulic oil may be a mineral hydraulic oil having a viscosity of 10 centistokes (cSt). The oil tank 16 is provided with an oil tank filler cap 17, an oil tank stop valve 18, and an oil filter 19. The outlet of the oil tank 16 is connected to the four air driven pumps through the stop valve 18 and the oil filter 19. The plunger oil air driven pump 15 is controlled by the plunger oil hydraulic control valve 12, the control oil / seal oil air driven pump 7 is controlled by the control oil / seal oil hydraulic control valve 8 and the control oil / seal oil air pump safety valve 9, the lift oil air driven pump 31 is controlled by the lift oil hydraulic control valve 28 and the lift oil air pump safety valve 29, and the fuel oil air driven pump 37 is controlled by the fuel oil hydraulic control valve 33 and the fuel oil air pump safety valve 34. The oil pressure from the plunger oil air driven pump 15 can be read from the plunger oil oil pressure gauge 13, the oil pressure from the control oil / seal oil air driven pump 7 can be read from the control oil / seal oil oil pressure gauge 6, and the oil pressure from the fuel oil air driven pump 37 can be read from the fuel oil oil pressure gauge 36.

[0095] A hydraulic accumulator 5 is also provided. The accumulator 5 may be one that can be charged with fuel oil up to a pressure of 250 bar. However, in the present test system 1, the maximum pressure of the fuel oil is 50 bar. The hydraulic accumulator 5 is a membrane type accumulator. It has a chamber separated by a rubber membrane. On one side of the membrane there is nitrogen at 20-25 bar and on the other side of the membrane there is hydraulic oil supplied from the fuel oil air driven pump 37. While the hydraulic oil pressure is 0 bar, the entire volume of the accumulator is filled with nitrogen. When the hydraulic oil pressure exceeds 2-25 bar, the nitrogen starts to be compressed as the hydraulic oil starts to fill the accumulator volume. The purpose of the accumulator 5 in the test system 1 is to accumulate hydraulic oil inside at a pressure of 20-25 bar and to reduce the hydraulic fluctuations coming from the fuel oil air driven pump 37.

[0096] The plunger oil directional control valve 10 is provided to open and close the supply of plunger oil that can be supplied to the plunger oil outlet 1g from the plunger oil air driven pump 15 or the nitrogen booster 20. The hydraulic pressure from the plunger oil air driven pump 15 can be read from the plunger oil hydraulic pressure gauge 13. The hydraulic pressure from the plunger oil air driven pump 15 can be released by the plunger oil hydraulic pressure release valve 11, in which case the released hydraulic oil flows back to the oil tank 16. A plunger oil hydraulic pressure relief valve 14 is provided. The plunger oil hydraulic pressure relief valve 14 is adjusted to a maximum operating pressure of 320 bar at the output side of the plunger oil hydraulic pressure air driven pump 15. When the hydraulic pressure of the plunger oil exceeds 320 bar, the plunger oil hydraulic pressure relief valve 14 opens and the hydraulic oil flows back to the oil tank 16.

[0097] The plunger oil directional control valve 10 is also connected to the nitrogen booster 20 through the booster oil hydraulic relief valve 21. The nitrogen booster 20 has an inlet chamber filled with nitrogen and an outlet chamber filled with hydraulic oil, and can boost the hydraulic oil by increasing the pressure of the nitrogen in the inlet chamber. When both the plunger oil hydraulic relief valve 11 and the plunger oil directional control valve 10 are closed, the hydraulic pressure in the outlet chamber of the nitrogen booster 20 can be determined by the pressure of the supplied nitrogen and the hydraulic pressure generated from the plunger oil air-driven pump 15. When the plunger oil directional control valve 10 is opened, hydraulic pressure is supplied to the plunger oil outlet 1g.

[0098] Fuel oil is supplied to the fuel oil outlet 1f from the fuel oil air driven pump 37. The oil pressure from the fuel oil air driven pump 37 can be read from the fuel oil pressure gauge 36. The oil pressure from the fuel oil air driven pump 37 can be released by the fuel oil pressure relief valve 32, in which case the released hydraulic oil flows back to the oil tank 16. To protect the fuel oil pressure gauge 36, a fuel oil pressure safety valve 35 is provided. The fuel oil pressure safety valve 35 is adjusted to a maximum operating pressure of 60 bar on the output side of the fuel oil air driven pump 37. When the fuel oil pressure exceeds 60 bar, the fuel oil safety valve 35 opens and the hydraulic oil flows back to the oil tank 16.

[0099] A control oil / seal oil directional control valve 2 is provided for opening and closing the oil supply from the control oil / seal oil air driven pump 7 to the seal oil outlet 1e or the control oil directional control valve 3. The control oil directional control valve 3 controls the opening and closing of the oil supply to the control oil outlet 1d. The hydraulic pressure from the control oil / seal oil air driven pump 7 can be read from a control oil / seal oil hydraulic pressure gauge 6. The hydraulic pressure from the control oil / seal oil air driven pump 7 can be relieved by the control oil hydraulic pressure relief valve 4, in which case the relieved hydraulic oil flows back to the oil tank 16.

[0100] Lift oil is supplied to the lift oil outlet 1h from the lift oil air driven pump 31. The hydraulic pressure from the lift oil air driven pump 31 can be read from the lift oil hydraulic pressure gauge 30. The hydraulic pressure from the lift oil air driven pump 31 can be released by the lift oil hydraulic pressure relief valve 27, in which case the released hydraulic oil flows back to the oil tank 16.

[0101] A constant oil valve 26 is provided for opening and closing the oil supply to the constant oil outlet 1i. Oil is supplied to the constant oil valve 26 directly from the oil tank 16 through the oil tank stop valve 18 and the oil filter 19. No air-driven pump for generating hydraulic pressure is provided in the oil supply line between the oil tank 16 and the constant oil outlet 1i. [Functional test of injection valve]

[0102] The functional tests include a test of the check valve 77, which requires that the nozzle valve piston shutoff shaft 62 be constantly held in a lifted position from the nozzle valve seat 88 in order to keep the nozzle valve open. The test of the check valve 77 is followed by a number of tests, with the nozzle valve piston shutoff shaft 62 in its normal operating mode. These tests include a test of the tightness of the nozzle valve piston shutoff shaft 62 against the nozzle valve seat 88, a test of the fuel injection sequence, and an indirect test of the intake one-way valve 70.

[0103] To perform a functional test of the injector 44 of Figure 2, the atomizer coupling nut 126 and the atomizer 43 are removed from the injector as shown in Figure 20. This leaves the spindle guide housing 124 uncovered and the tip of the nozzle valve piston shutoff shaft 62 protrudes beyond the end of the spindle guide housing 124. The spindle guide coupling nut 127 is maintained. When performing a functional test, the injector 44 of Figure 20 is mounted in a functional test valve holder 45 (see Figure 21).

[0104] The plunger oil connecting piece 49a is connected to the plunger oil inlet port 49b, the control oil connecting piece 50 is connected to the control oil inlet port 130, the seal oil connecting piece 51 is connected to the seal oil inlet port 128, the constant oil connecting piece 52 is connected to the constant oil inlet port 129, and the air bleed stop valve 53 is connected to the air bleed outlet 55. The top cover 120 of the valve 44 is fixed to the function test valve holder 45 by two function test valve connecting nuts 46d.

[0105] Before starting the test procedure, the test system 1 must be initialized as follows.

[0106] The air inlet 1b is connected to an external source of compressed air at a minimum of 7 bar and a maximum of 10 bar, and the gas inlet 1a is connected to an external source of nitrogen at a minimum of 80 bar.

[0107] The hydraulic accumulator 5 is filled with nitrogen up to 20-25 bar.

[0108] Adjust the fuel oil pressure relief valve 35 to 60 bar pressure. (The purpose of the relief valve 35 is to protect the fuel oil pressure gauge 36 which has an operating range of 0-60 bar.) Adjust the safety valve 14 to 320 bar. Set all pressure relief valves 4, 11, 27, 32 to open.

[0109] The pressure control valves 33, 8, 28, 12 are set in the closed position so that the valve outlet pressure is 0 bar.

[0110] Adjust the safety valve of each air pump to maximum pressure. Regulating the pressure of the fuel oil air pump safety valve 34 so that the fuel oil air driven pump 37 can provide a maximum oil pressure of 50 bar. Regulating the pressure of the control oil / seal oil air pump safety valve 9 so that the control oil / seal oil air driven pump 7 can provide a maximum hydraulic pressure of 300 bar. Regulating the pressure of the lift oil air pump safety valve 29 so that the lift oil air driven pump 31 can provide a maximum hydraulic pressure of 300 bar.

[0111] The oil tank stop valve 18 is set to open.

[0112] The gas stop valve 24 is set to closed.

[0113] The oil tank 16 is filled with clean hydraulic oil having a viscosity of 7 to 10 cSt.

[0114] Each flexible hose is connected to the oil outlets 1f, 1d, 1e, 1i, 1h, and 1g, respectively. The other ends of these flexible hoses are equipped with normally closed quick couplings. The quick couplings open when they are connected to the corresponding connections of the injection valve and the test valve holder. The gas exhaust port 1c is equipped with a normally closed quick coupling.

[0115] The control oil outlet 1d is connected to a control oil connecting piece 50, the seal oil outlet 1e is connected to a seal oil connecting piece 51, the plunger oil outlet 1g is connected to a plunger oil connecting piece 49a, and the constant oil outlet 1i is connected to a constant oil connecting piece 52. The fuel oil outlet 1f is connected to a fuel oil inlet connecting piece 47 connected to a functional test sleeve 46e, and the lift oil outlet 1h is connected to a lift oil connecting piece 48b connected to a nozzle valve piston lift unit 48a. [Deaeration]

[0116] Prior to testing the check valve 77, the valve 44 is vented. 1. Connect the air bleed drain hose 54 to the air bleed stop valve 53, and connect the air bleed drain hose 54 to the oil injection chamber 59 through the drain hose hole 60. 2. Set the control oil / seal oil valve 2 of the test apparatus 1 to the sealing position. 3. Close the control oil hydraulic relief valve 4. 4. To lubricate or seal the plunger piston 58 and hydraulic piston 64, the control oil / seal oil hydraulic control valve 8 and the control oil / seal oil hydraulic gauge 6 are used to increase the seal oil hydraulic pressure to 80 bar. 5. Open the air bleed stop valve 53. 6. Close the booster oil hydraulic relief valve 21. 7. Close the plunger oil pressure relief valve 11. 8. Set the plunger oil directional control valve 10 to the open position. 9. Using the plunger oil pressure control valve 12 and the plunger oil pressure gauge 13, increase the plunger oil pressure to 10-50 bar. As a result, the plunger oil passes through the plunger oil connecting piece 49a and the cover plunger oil passage 63, and flows into the plunger oil chamber 57a until all the air is released from the plunger oil chamber 57a. The air released from the plunger oil chamber 57a flows into the injection chamber 59 through the cover passages 56c, 56b, 56a, the air bleed stop valve 53, and the air bleed drain hose 54. 10. Check that no air bubbles have entered the injection chamber 59 from the air bleed drain hose 54. 11. When no more air bubbles are entering the injection chamber 59 through the air bleed drain hose 54, close the air bleed stop valve 53. 12. Set the control oil / seal oil valve 2 of the test rig 1 to the control position. 13. Set the control oil directional control valve 3 to the open position. 14. Open the constant oil valve 26. 15. Close the control oil hydraulic relief valve 4. 16. Use the control oil / seal oil pressure control valve 8 and the control oil / seal oil pressure gauge 6 to increase the control oil pressure to 10~50 bar. 17. Apply control oil to control oil connecting piece 50 for 20 seconds. By applying control oil at a pressure in the range of 10 to 50 bar for 20 seconds, air is discharged from the hydraulic piston operating chamber 65 formed above the hydraulic piston 64 through the control oil drain restriction 143b and the drain passages 143a, 142, through the constant oil port 129 and the constant oil connecting piece, and through the constant oil valve 26 to the oil tank 16. [Test of check valve 77]

[0117] For this test, the nozzle valve piston shutoff shaft 62 must be held in a lifted position off the nozzle valve seat 88 to hold the nozzle valve open.

[0118] 1. Raise the lift oil pressure to 300 bar using the lift oil pressure control valve 28 and lift oil pressure gauge 30. The lift oil pressure relief valve 27 must be closed. 2. Supply lift oil to the lift oil connecting piece 48b at a pressure of 300 bar. As a result, lift oil flows through lift oil passage 66 to lift piston 67. Then, lift piston 67 lifts and pushes nozzle valve piston shutoff shaft 62 up a distance 68 of about 2 mm, maintaining nozzle valve piston shutoff shaft 62 in an open position. Nozzle valve piston shutoff shaft 62 is connected to hydraulic piston 64, which is also pushed up the same distance.

[0119] 3. Set the control oil / seal oil valve 2 of the test apparatus 1 to the sealing position. 4. Close the control oil hydraulic relief valve 4. 5. To lubricate or seal the plunger piston 58 and hydraulic piston 64, the control oil / seal oil hydraulic control valve 8 and control oil / seal oil hydraulic gauge 6 are used to increase the seal oil hydraulic pressure to 80 bar. 6. Close the booster oil hydraulic relief valve 21. 7. Close the plunger oil pressure relief valve 11. 8. Set the plunger oil directional control valve 10 to the open position.

[0120] 9. Using the plunger oil pressure control valve 12 and the plunger oil pressure gauge 13, slowly increase the plunger oil pressure from 10 to 50 bar, and then increase it to 300 bar. This causes the plunger piston 58 to move slowly downward until it reaches the bottom of the plunger compression chamber 74. 10. Close the fuel oil hydraulic relief valve 32. 11. Using the fuel oil pressure control valve 33 and the fuel oil pressure gauge 36, increase the fuel oil pressure to 30 bar and fill the hydraulic accumulator 5. 12. Supply fuel oil to the fuel oil inlet connecting piece 47 at a hydraulic pressure of 30 bar. The fuel oil then flows through the fuel inlet passage 71, into the suction valve inlet port 72 and into the suction one-way valve 70, through the plunger chamber supply passage 73, through the plunger piston fuel oil opening 57b and the check valve supply passage 75, and into the check valve 77. If the nozzle valve 77 is not properly closed, leakage will occur at the nozzle valve seat 76 and fuel oil will flow through the nozzle valve chamber supply passages 78a, 78b, 79a, 79b, 80a, 80b to the nozzle valve chamber 81. Fuel oil will flow from the nozzle valve chamber 81 to the nozzle valve lower chamber 82, pass through the lifted nozzle valve piston shutoff shaft 62, enter the lift unit fuel oil leak paths 83, 84, and exit through the lift unit fuel oil outlet 85 to the oil injection chamber 59.

[0121] 13. Check that no oil is dripping or flowing into the injection chamber 59 from the lift unit fuel oil outlet 85. 14. Using the fuel oil pressure control valve 33 and fuel oil pressure gauge 36, slowly increase the fuel oil pressure to above 30 bar while observing oil droplets or flow from the lift unit fuel oil outlet 85 into the oil injection chamber 59 until the check valve 77 opens. The check valve 77 has a check valve spindle 86 that is pressed against the check valve seat 76 by a check valve spring 87b, and the check valve 77 opens when the pressure of the fuel oil acting on the check valve spindle 86 is greater than the pressure of the spring 87b. 15. Note the observed opening pressure of check valve 77. 16. Open the fuel oil pressure relief valve 32 and the fuel oil pressure control valve 33 to release the fuel oil pressure. This allows the check valve spindle 86 to properly close against the check valve seat 76 and ensure intimate contact between the valve spindle 86 and the valve seat 76 .

[0122] 17. Using the fuel oil pressure control valve 33 and fuel oil pressure gauge 36, slowly increase the fuel oil pressure to equal the observed check valve opening pressure minus 3 to 5 bar. 18. Fill the hydraulic accumulator 5 with the fuel oil air driven pump. 19. Check that fuel oil is not dripping or flowing into the injection chamber 59 from the lift unit fuel oil outlet 85. If any fuel oil comes out, it means the check valve is leaking, but a small drop of oil is acceptable as it may be fuel oil that has not yet been discharged. 20. Turn off the fuel oil pneumatic pump 37 using the fuel oil hydraulic control valve 33. 21. Wait 15 seconds for the fuel oil pressure gauge 36 to stabilize and record the pressure. 22. Use a stopwatch to wait 60 seconds and observe how much the pressure drops.

[0123] If the pressure does not drop by more than 2 bar, the check valve 77 passes the test. Testing the Fitting of the Nozzle Valve Piston Shutoff Shaft 62 Against the Nozzle Valve Seat 88

[0124] In this test, the nozzle valve piston shutoff shaft 62 is not constantly held in a lifted position from the nozzle valve seat 88 and is in its normal operating mode.

[0125] 1. Open the lift oil hydraulic relief valve 27 and the lift oil hydraulic control valve 28 to release the lift oil hydraulic pressure. Releasing the lift oil pressure releases the nozzle valve piston shutoff shaft 62, which then engages the nozzle valve seat 88 and maintains a tight seal. 2. Inject fuel oil at a pressure 5 bar higher than the observed opening pressure of the check valve 77. Since the check valve 77 is open, the fuel oil fills the nozzle valve chamber 81 . 3. Check that fuel oil is not dripping or flowing into the injection chamber 59 from the lift unit fuel oil outlet 85. If the seal between the nozzle valve piston shutoff shaft 82 and the nozzle valve seat 88 is tight, no oil should be observed coming out of the lift unit fuel oil outlet 85. 4. Open the fuel oil pressure relief valve 32 and the fuel oil pressure control valve 33 to release the fuel oil pressure. 5. Open the control oil hydraulic relief valve 4 and the control oil / seal oil hydraulic control valve 8 to release the seal oil hydraulic pressure. 6. Close the constant oil valve 26. 7. Open the plunger oil pressure relief valve 11 and the plunger oil pressure control valve 12 to release the plunger oil pressure. 8. Open the booster oil hydraulic relief valve 21. 9. Supply nitrogen at 80 to 100 bar from the gas inlet port 1a to the nitrogen booster 21. 10. Close the plunger oil directional control valve 10 and the plunger oil hydraulic release valve 11. 11. Using the plunger oil pressure control valve 12 and plunger oil pressure gauge 13, increase the pressure in the nitrogen booster 21 to 150 bar. 12. To lubricate or seal the plunger piston 58 and hydraulic piston 64, the control oil / seal oil pressure control valve 8 and control oil / seal oil pressure gauge 6 are used to increase the seal oil pressure to 80 bar.

[0126] 13. Increase the fuel oil pressure to 30 bar using the fuel oil pressure control valve 33 and fuel oil pressure gauge 36. When increasing the fuel oil pressure, the fuel oil pressure relief valve 32 must be closed. Since there is no pressure above the plunger piston 58, the plunger 58 is lifted by the pressure of the fuel oil flowing in from the suction one-way valve 70. When the plunger piston 58 is lifted to the top, the plunger compression chamber leak path 90 merges with the plunger compression chamber leak path 91, and the fuel oil starts to leak from the plunger compression chamber 74 through the plunger compression chamber leak paths 89, 90, 91 to the fuel oil leak chamber 92. The fuel oil flows from the fuel oil leak chamber 92 to the functional test sleeve fuel oil leak port 93, and reaches the oil injection chamber 59 through the fuel oil discharge sleeve 94. The pressure of the nozzle valve piston shutoff shaft 62 is determined by the pressure acting on the area between the nozzle valve seat 88 and the diameter of the nozzle valve piston guide 95. The opening pressure of the nozzle valve piston shutoff shaft 62 is the pressure required to overcome the force of the nozzle valve spring 96 and should be in the range of 388 to 447 bar. The hydraulic gear of the piston plunger 58 is 2.47. Therefore, the pressure corresponding to opening the nozzle valve piston shutoff shaft 62 from the pressure supplied to the plunger oil chamber 57a at the top of the plunger piston 58 is 157 to 181 bar.

[0127] 14. Set the plunger oil directional control valve 10 to the open position to apply the plunger oil pressure stored in the nitrogen booster 20 to the top of the plunger piston 58. 15. Check that oil is not dripping or flowing into the oil injection chamber 59 via the lift unit fuel oil outlet 85. There should be no oil being injected into the oil injection chamber 59 from the lift unit port 85. Any oil leakage between the plunger piston 58 holding the plunger compression chamber 74 and the pump barrel body 122 can be observed by leakage into the oil injection chamber 59 through the plunger compression chamber leak path 91, the fuel oil leak chamber 92, the functional test sleeve fuel oil leak port 93, and the fuel oil drain sleeve 94. 16. Close plunger oil directional control valve 10. 17. Using the plunger oil pressure control valve 12 and plunger oil pressure gauge 13, increase the pressure in the nitrogen booster 21 to 155 bar. 18. Set the plunger oil directional control valve 10 to the open position to apply the plunger oil pressure stored in the nitrogen booster 20 to the top of the plunger piston 58. 19. Check that fuel oil is not dripping or flowing into the oil injection chamber 59 via the lift unit fuel oil outlet 85.

[0128] 20. Close plunger oil directional control valve 10. Repeat test steps 17 to 20 while increasing the plunger oil pressure by 5 bar each time: 160 bar, 165 bar, 170 bar, 175 bar, 180 bar, and 185 bar. Observe at which plunger oil pressure the nozzle valve piston shutoff shaft 62 lifts, and the fuel oil flows through the nozzle valve seat 88 into the lift unit fuel oil leak paths 83 and 84 and comes out from the lift unit fuel oil outlet 85. When the nozzle valve shutoff shaft 62 lifts off the valve seat 88 and fuel oil flows out of the fuel oil outlet 85, note down the plunger oil pressure, and multiply this plunger oil pressure by the gear ratio 2.47 to convert it into the pressure inside the nozzle valve chamber 81. Note down this pressure. Repeat steps 17-20 while supplying a plunger oil pressure of 5-10 bar less than the valve opening pressure to the top of the plunger piston 58, to recheck the fit between the valve seat 88 and the shutoff shaft 62. Observe that no fuel oil flows from the lift unit fuel oil outlet 85.

[0129] The passing criterion for this test is that the valve opening pressure is in the range of 155 to 185 bar. [Fuel injection sequence test]

[0130] 1. Open the fuel oil pressure relief valve 32 and the fuel oil pressure control valve 33 to release the fuel oil pressure. 2. Open the control oil hydraulic relief valve 4 and the control oil / seal oil hydraulic control valve 8 to release the seal oil hydraulic pressure. 3. Close the plunger oil directional control valve 10. 4. Close the constant oil valve 26. 5. Set the control oil / seal oil valve 2 to the control position and set the control oil directional control valve 3 to the open position. 6. Close the control oil hydraulic relief valve 4 and use the control oil / seal oil hydraulic control valve 8 and the control oil / seal oil hydraulic gauge 6 to increase the control oil hydraulic pressure to 300 bar. The nozzle valve piston shutoff shaft 62 is prevented from opening by providing a controlled oil pressure of 300 bar on the hydraulic piston 64 . 7. Close the plunger oil pressure relief valve 11. Using the plunger oil pressure control valve 12 and plunger oil pressure gauge 13, increase the pressure in the nitrogen booster 21 to 300 bar. 8. Close the fuel oil pressure relief valve 32 and use the fuel oil pressure control valve 33 and fuel oil pressure gauge 36 to increase the fuel oil pressure to 30 bar. Since there is no pressure above the plunger piston 58, fuel oil entering the plunger compression chamber 74 through the suction one-way valve 70 lifts the plunger piston 58.

[0131] 9. The plunger oil directional control valve 10 is opened and the boosted plunger oil pressure is applied to the top of the plunger piston 58. 10. Check that fuel oil is not dripping or flowing into the oil injection chamber 59 via the lift unit fuel oil outlet 85. The control oil pushes the hydraulic piston 64 down, which in turn pushes the shutoff shaft 62 down, so that no fuel oil should be sprayed from the fuel oil outlet 85 . 11. Close plunger oil directional control valve 10. 12. Using the plunger oil pressure control valve 12 and plunger oil pressure gauge 13, increase the pressure in the nitrogen booster 21 to 300 bar. 13. Ensure that the control oil / seal oil valve 2 is set to the control position and the control oil directional control valve 3 is set to the open position. 14. Check that the control oil pressure is up to 300 bar. 15. Open the plunger oil directional control valve 10 and apply the boosted plunger oil pressure to the top of the plunger piston 58. 16. Wait 1 to 2 seconds.

[0132] 17. Close the control oil directional control valve 3. The control oil directional control valve 3 is a three-way valve with two positions. When in the closed position, no fluid can flow from the control oil / seal oil valve 2 to the control oil outlet 1d, but fluid can flow from the control oil outlet 1d to the oil tank 16. Thus, when the valve 3 is closed, the control oil pressure at port 1d is relieved, and when the valve 2 is in the open position, oil flows through the valve 3 via the valve 2, and the control oil outlet 1d is subjected to control oil pressure. The pressure of the fuel oil in the nozzle valve chamber 81 can lift the nozzle valve piston shutoff shaft 62 .

[0133] 18. Check that fuel oil is not dripping or flowing into the oil injection chamber 59 via the lift unit fuel oil outlet 85. Injection of fuel into the oil injection chamber 59 would have occurred.

[0134] 19. Open the control oil directional control valve 3. 20. Using the control oil / seal oil pressure control valve 8 and the control oil / seal oil pressure gauge 6, increase the control oil pressure to 300 bar. 21. Check that fuel oil is not dripping or flowing into the oil injection chamber 59 via the lift unit fuel oil outlet 85. The control oil pushes the hydraulic piston 64 down, which in turn pushes the shutoff shaft 62 down, so that no fuel oil should be sprayed from the fuel oil outlet 85 .

[0135] Repeat steps 1 to 21 several times. [Suction one-way valve test 70]

[0136] The suction one-way valve 70 is indirectly tested.

[0137] 1. With the lift oil hydraulic relief valve 27 closed, the lift oil hydraulic pressure is increased to 300 bar using the lift oil hydraulic control valve 28 and the lift oil hydraulic pressure gauge 30, and lift oil is supplied to the lift oil connecting piece 48b at a pressure of 300 bar. As a result, lift oil flows through lift oil passage 66 to lift piston 67. Then, lift piston 67 lifts and pushes nozzle valve piston shutoff shaft 62 up a distance 68 of about 2 mm, maintaining nozzle valve piston shutoff shaft 62 in an open position. Nozzle valve piston shutoff shaft 62 is connected to hydraulic piston 64, which is also pushed up the same distance.

[0138] 2. Close the plunger oil pressure relief valve 11 and the booster oil pressure relief valve 21, and with the plunger oil directional control valve 10 open, use the plunger oil pressure control valve 12 and the plunger oil pressure gauge 13 to slowly increase the plunger oil pressure to 10-50 bar, and then further increase it to 300 bar. When increasing the plunger oil pressure, close the plunger oil pressure relief valve 11. This causes the plunger piston 58 to move slowly downward until it reaches the bottom of the plunger compression chamber 74.

[0139] 3. With the fuel oil pressure relief valve 32 closed, use the fuel oil pressure control valve 33 and fuel oil pressure gauge 36 to slowly increase the fuel oil pressure above the observed check valve 77 opening pressure. 4. Check that fuel oil is not dripping or flowing into the oil injection chamber 59 via the lift unit fuel oil outlet 85. If the check valve 77 does not open, no fuel oil will be coming out of the fuel oil outlet 85, indicating that either the check valve spindle 86 or the spindle of the suction one-way valve 70 is stuck.

[0140] If the needle of the fuel oil pressure gauge 36 rises to 60 bar during a fit test of the nozzle valve piston shutoff shaft 62 against the nozzle valve seat 88 or during a fuel injection sequence test, it is an indication that a leak is occurring from the valve seat of the suction DTS air valve 70. [Leak detection test]

[0141] The fully assembled injector valve 44 of Figure 2 is subjected to a leak detection test. In performing the leak detection test, the fully assembled injector valve 44 is placed in the detector valve holder 97a and supplied with 7 bar of air to detect any leaks.

[0142] 1. Remove the injector valve 44 from the functional test valve holder 45 and install the atomizer coupling nut 126 and atomizer 43 to obtain the fully assembled injector valve 44 of Figure 2. Tighten the atomizer coupling nut 126 to the recommended torque. The valve 44 under test also holds a control oil connecting piece 50 , a seal oil connecting piece 51 , a plunger oil connecting piece 49 a , a constant oil connecting piece 52 , and an air bleed stop valve 53 . 2. Insert the assembled injector valve 44 into the detection test valve holder 97a and tighten the connecting nut 46d to secure the valve 44 in place (see FIG. 27).

[0143] 3. Connect the detection test hoses 98, 99, 100, 101, 102, 103, 104, and 105 to the check valves 109a to 109h as follows (see FIG. 29). · Connect the hose 98 to the valve 109a, which is connected to the control oil connecting piece 50. · Connect the hose 99 to the valve 109b and connect the valve 109b to the seal oil connecting piece 51. · Connect the hose 100 to the valve 109c and connect the valve 109c to the constant oil connecting piece 52. · Connect hose 101 to valve 109d and connect valve 109d to the DTS air outlet port II (113). · Connect hose 102 to valve 109e and connect valve 109e to the DTS air outlet port III (112). · Connect the hose 103 to the valve 109f, and connect the valve 109f to the DTS air outlet port I (111). · Connect hose 104 to valve 109g and connect valve 109g to the DTS lower air outlet port 110. · Connect hose 105 to valve 109h and connect valve 109h to the DTS bottom air outlet port 114.

[0144] 4. The hole of the plunger oil connecting piece 49b is blocked with the plunger oil plug 115, and the air bleeding stop valve 53 is closed. 5. Insert all flexible hoses 98, 99, 100, 101, 102, 103, 104, 105 into detection test chamber 106 which holds the liquid. Valve 108 is a detection test fluid drain valve (see Figures 28 and 29) which drains fluid from the bottom of detection test valve holder 97a as needed.

[0145] 7. Supply 7 bar of air to the DTS air inlet port 107 and feed it to the sensing sleeve 97a. Compressed air flows from air intake port 107 through air inlet passage 195 into air inlet chamber 196 (see FIG. 28).

[0146] Compressed air can flow from the air inlet chamber 196 to the upper leak oil outlet 166, through the upper leak oil passage 167, the middle leak oil collection passage 169, the middle leak oil outlet 197, and into the middle outer leak oil chamber 198. If air leaks through the seal ring 199 (see FIG. 16), the air will flow from the DTS lower air exhaust chamber 203 to the DTS lower air outlet port 110, through the valve 109, the hose 104, and into the test liquid chamber 106. Air leakage through the seal ring 199 can be observed as air bubbles in the liquid chamber 106.

[0147] If there is a leak between the atomizer coupling nut 126 and the atomizer 43, air will flow from the air inlet chamber 196 through the middle leak oil outlet channel 197, the atomizer fuel oil leak path 168, to the atomizer fuel oil leak chamber 194, and to the bottom air outlet chamber 204 (see Figures 16 and 28). Air will flow from the bottom air outlet chamber 204 through the bottom air outlet port 114, the valve 109h, the hose 105, and into the test liquid chamber 106. A leak between the coupling nut 126 and the atomizer 43 can be observed as air bubbles in the liquid chamber 106.

[0148] If there is a leak at barrel body outer seal ring 209, air will flow from air inlet chamber 196 to barrel body air outlet chamber I (210), to barrel body air outlet port I (111), and from port 111 through valve 109g and hose 104 into test fluid chamber 106. A leak will be observed as air bubbles in fluid chamber 106.

[0149] Air flows from the air inlet chamber 196 to the upper oil leak port 166, through the upper oil leak path 167 and into the middle upper leak oil chamber 170. See Figures 16 and 17. If there is a leak through the fourth middle upper seal ring 175 (see Figure 18), the air flows from the middle upper leak oil chamber 170 to the second control oil / seal oil leak path 151, through the first control oil / seal oil leak path 150 to the oil leak port 158 ​​(see Figure 7), through the outlet 158 ​​through the barrel body outlet chamber II (211) to the barrel body air outlet port II (113) see Figure 28. From the port 113, it enters the test liquid chamber 106 through the valve 109d and the hose 10. Leaks through the seal ring 175 are observed as air bubbles in the liquid chamber 106.

[0150] Compressed air flows from air inlet chamber 196 to upper oil leak port 166, through upper oil leak path 167, into upper oil leak port 165, and into barrel body air outlet chamber III (212) (see Figures 16 and 28). If there is a leak through second barrel body outer seal ring 206, air will flow from barrel body air outlet chamber III (212) to barrel body outlet chamber II (211) and into air outlet port II (113). From port 113, air will flow through valve 109d and hose 10 into test liquid chamber 106. Leaks through seal ring 206 will be observed as air bubbles in the liquid chamber 106.

[0151] Air flows from the air inlet chamber 196 to the upper oil leak port 166, and enters the middle upper leak oil chamber (112) through the upper oil leak path 167. See Figures 16 and 17. If there is a leak through the fifth middle upper seal ring 176 (see Figure 18), air will flow from the middle upper leak oil chamber 170 to the second fuel oil leak path 163, and through the third fuel oil leak path 164 to the fuel leak port 92 (see Figures 15 and 28). Then, air can flow from the leak port 92 to the barrel body outlet port III (112), and enter the test liquid chamber 106 through the valve 109e and the hose 102. Leaks through the fifth middle upper seal ring 176 are observed as air bubbles in the liquid chamber 106.

[0152] Compressed air flows from the air inlet chamber 196 to the upper oil leak port 166, through the upper oil leak path 167 into the upper oil leak port 165, and into the barrel body air outlet chamber III (212) (see Figures 16 and 28). If there is a leak through the third barrel body outer seal ring 207, air will flow from the barrel body air outlet chamber III (212) to the fuel leak port 92. The air can then flow from the leak port 92 to the barrel body outlet port III (112), through the valve 109e and hose 102, and into the test liquid chamber 106. A leak through the third barrel body outer seal ring 207 will be observed as air bubbles in the liquid chamber 106.

[0153] Air flows from the air inlet chamber 196 to the upper oil leak port 166, and enters the middle upper leak oil chamber 170 through the upper oil leak path 167. See Figures 16 and 17. If there is leakage from the third middle upper seal ring 174 (see Figure 18), air flows from the middle upper leak oil chamber 170 to the seal oil passage 133, and from the seal oil passage 133 through the seal oil passages 132 and 131 to the seal oil inlet port 128 and the seal oil connecting piece 51. Then, from the connecting piece 51, it enters the test liquid chamber 106 through the valve 109b and the hose 99. Leakage from the third middle upper seal ring 174 is observed as air bubbles in the liquid chamber 106.

[0154] Air flows from the air inlet chamber 196 to the upper oil leak port 166, and enters the middle upper leak oil chamber 170 through the upper oil leak path 167. See Figures 16 and 17. If there is a leak from the second middle upper seal ring 173 (see Figure 18), air flows from the middle upper leak oil chamber 170 to the controlled oil discharge path 142, to the constant oil inlet port 129 and the constant oil connecting piece 52. Then, it flows from the connecting piece 52 through the valve 109c and the hose 100 into the test liquid chamber 106. Leaks through the second middle upper seal ring 173 are observed as air bubbles in the liquid chamber 106.

[0155] Air flows from the air inlet chamber 196 to the upper oil leak port 166, and enters the middle upper leak oil chamber 170 through the upper oil leak path 167. See Figures 16 and 17. If there is a leak from the first middle upper seal ring 172 (see Figure 18), the air flows from the middle upper leak oil chamber 170 to the control oil supply path 140, and then to the control oil inlet port 130 and the control oil connecting piece 50. Then, it flows from the connecting piece 50 through the valve 109a and the hose 98 into the test liquid chamber 106. The leak from the first middle upper seal ring 172 is observed as air bubbles in the liquid chamber 106.

[0156] 8. Observe the test fluid chamber 106 for two minutes. Bubbles emerging from any of the detection test hoses 98-105 is evidence of an internal leak in the injector valve 44. This test is passed if no more than two bubbles are observed in each of hoses 98-105 within 60 seconds.

[0157] The present invention has been described using various examples. However, upon reviewing the specification, drawings, and claims of this application, those skilled in the art will understand and be able to embody many variations in addition to the described embodiments in implementing the claimed invention. The words "comprise", "have", and "include" in the claims do not exclude the presence of elements or steps not described. Even if the number of elements described in the claims is not explicitly stated as being plural, it does not exclude the presence of the elements in plural. [Explanation of symbols]

[0158] 1. Test system 1a Gas inlet 1b Air inlet 1c Gas outlet 1d...Control oil outlet 1e Seal oil outlet 1f...Fuel oil outlet 1g Plunger oil outlet 1h···Lift oil outlet 1i···Constant oil outlet 2. Control oil / seal oil valve 3. Control oil directional control valve 4. Control oil pressure relief valve 5. Hydraulic accumulator 6···Control oil / seal oil pressure gauge 7···Control oil / seal oil air-driven pump 8···Control oil / seal oil hydraulic control valve 9. Control oil / seal oil air pump safety valve 10. Plunger oil directional control valve 11... Plunger oil pressure relief valve 12 Plunger oil pressure control valve 13. Plunger oil pressure gauge 14···Plunger oil hydraulic relief valve 15···Plunger oil air driven pump 16. Oil tank 17···Oil tank filler cap 18 Oil tank stop valve 19. Oil filter 20. Nitrogen Booster 21 Booster oil pressure relief valve 22 Nitrogen inlet check valve 23 Nitrogen gas pressure control valve 24 Gas stop valve 25 Nitrogen gas pressure gauge 26···Constant oil valve 27 Lift oil hydraulic relief valve 28 Lift oil hydraulic control valve 29 Lift oil air pump safety valve 30···Lift oil pressure gauge 31 Lift oil air driven pump 32 Fuel oil hydraulic relief valve 33 Fuel oil hydraulic control valve 34...Fuel oil air pump safety valve 35 Fuel oil hydraulic safety valve 36 Fuel oil pressure gauge 37...Fuel oil air driven pump 44 Fuel booster injection valve (FBIV) 43 Atomizer 120···Top cover 49b Plunger oil inlet port 130 Control oil inlet port 128 Seal oil inlet port 129···Constant oil inlet port 121 Barrel flange 122···Barrel body 123 Middle section 124···Spindle guide housing 125···Hydraulic piston bushing 127···Spindle guide connecting nut 126 Atomizer coupling nut 201···Spindle guide housing seal 63 Cover plunger oil passage 56a, 56b, 56c... Cover channel 55 Air vent port 57a Plunger oil chamber 58 Plunger piston 57b Plunger piston fuel oil opening 156 Plunger piston head chamber 74 Plunger compression chamber 187 Plunger piston head seal 188 Plunger piston chamber seal 148, 149 Plunger piston head chamber leak path 157,158···Oil leak port 89, 90, 91... Plunger compression chamber leak path 92 Fuel oil leak 135 Plunger piston sealing hole 136 Plunger piston sealed chamber 131, 132, 133, 134...Seal oil passage 70....One-way suction valve 72....Fuel inlet suction valve 73 Plunger chamber supply line 77 Check valve 75....Check valve supply line 76 Check valve seat 86 Check valve spindle 87a Check valve housing 87b Check valve spring 186....Check valve upper chamber 185 Check valve seal 144, 146 Check valve leak path 145,147 Check valve leak chamber 78a, 78b, 79a, 79b, 80a, 80b Nozzle valve chamber supply passage 140, 141... Control oil supply path 142, 143a... Control oil drain passage (Drain passages 142 and 143a are always connected to oil port 129) 143b... Control oil discharge restriction section 64 Hydraulic piston 189 Hydraulic piston seal 65 Hydraulic piston working chamber 184 Hydraulic piston working chamber seal 155 Hydraulic piston chamber 190,191,192,193···Hydraulic piston bushing seal 137 Hydraulic piston seal hole 138 Hydraulic piston seal 139 Hydraulic piston sealed chamber 154 Hydraulic piston bushing leak path 153 Hydraulic piston bushing leak chamber 150, 151, 152...Leak paths for control oil and seal oil 61a Nozzle valve 61b Nozzle valve opening 62 Nozzle valve piston shutoff shaft 61c Nozzle valve piston shutoff shaft tip 95 Nozzle valve piston guide 88 Nozzle valve seat 81 Nozzle valve chamber 96 Nozzle valve spring 82 Nozzle valve lower chamber 159 Nozzle valve piston leak chamber 161 Nozzle valve bushing leak chamber 160, 162, 163, 164... Fuel oil leak path 194 Atomizer fuel oil leak chamber 168 Atomizer fuel oil leak path 169...Middle leak oil collection channel 197 Middle leak oil drain passage 198 Middle outer leak oil chamber 167···Upper oil leak path 165,166···Upper oil leak port 170···Middle upper leak oil chamber 171 Spindle guide upper leak oil chamber 172, 173, 174, 175, 176, 177, 178...Middle section upper seal ring 179, 180, 181, 182, 183···Spindle guide upper seal ring 199···Spindle guide connecting nut·Inner seal ring 200···Spindle guide connecting nut·Outer seal ring 205, 206, 207, 208, 209...Barrel body outer seal ring 49a···Plunger oil connecting piece 50···Control oil connecting piece 51 Seal oil connecting piece 52···Constant oil connecting piece 53 Air bleed stop valve 54 Air bleed drain hose 45···Function test valve holder 46a···Function test top plate 46b Nozzle valve piston lift unit 46c···Valve holder nut 46d···Function test valve connection nut 46e···Functional test sleeve 59...Oil injection chamber 60 Drain hose hole 47 Fuel oil inlet connecting piece 48b···Lift oil connecting piece 66 Lift oil passage 67 Lift piston 68 Piston lift distance 83, 84 Lift unit fuel oil leak path 85···Lift unit fuel oil outlet 71...Fuel inflow path 93···Functional test sleeve fuel oil leak port 94...Fuel oil drain sleeve 97a···Detection test valve holder 97b... Detection test sleeve 97c···Detection test top plate 97d... Bottom plate for detection test 115···Plunger oil plug 107···DTS air inlet port 195···DTS air inlet 196···DTS Air Inlet Chamber 203···DTS Lower Air Outlet Chamber 110···DTS lower air outlet port 204···DTS bottom air exhaust chamber 114···DTS bottom air outlet port 210···DTS Barrel Body Air Exhaust Chamber I 111···DTS Barrel Body Air Exit Port I 211···DTS Barrel Body Air Exhaust Chamber II 113···DTS Barrel Body Air Exit Port II 212···DTS Barrel Body Air Exhaust Chamber III 112···DTS Barrel Body Air Exit Port III 108 Detection test liquid discharge valve 98,99,100,101,102,103,104,105...Detection test hose 109a, 109b, 109c, 109d, 109e, 109f, 109g, 109h...Check valve 106 Detection test liquid chamber

Claims

1. 1. A method for testing an injection valve for an internal combustion engine, comprising: The injection valve is a plunger piston sealing chamber having a plunger piston for forming a plunger compression chamber, the plunger piston having a plunger piston fuel oil opening at its bottom, controlled by supplying plunger oil through a cover plunger oil supply passage, the plunger oil being supplied by plunger oil hydraulic pressure; a suction one-way valve for taking in fuel oil through the suction valve fuel inlet, and a plunger chamber supply line for supplying fuel oil from the suction one-way valve to the plunger compression chamber or the plunger piston fuel oil opening; a check valve in fluid communication with the plunger compression chamber or the plunger piston fuel oil opening through a check valve supply line for supplying fuel oil to the check valve; a nozzle valve including a nozzle valve chamber, a nozzle valve piston shutoff shaft, a nozzle valve spring, a nozzle valve seat, and a nozzle valve opening, wherein the nozzle valve piston shutoff shaft has a nozzle valve piston shutoff shaft tip that protrudes through the opening of the nozzle valve; a plurality of nozzle valve chamber supply passages providing fluid connections from the check valve to the nozzle valve chamber for supplying fuel oil from the plunger compression chamber or the plunger piston fuel oil opening through the check valve to the nozzle valve chamber; Equipped with (a) the method includes applying a predetermined lift pressure to a tip of the nozzle valve piston shutoff shaft protruding through the opening of the nozzle valve, the lift pressure being higher than a spring force exerted by the nozzle valve spring on the nozzle valve piston shutoff shaft, thereby maintaining the nozzle valve piston shutoff shaft in a position lifted from a nozzle valve seat and in a position where the nozzle valve is open; (b) the method further includes supplying plunger oil to the plunger piston through the cover plunger oil supply passage at a first test plunger oil oil pressure, the first test plunger oil oil pressure being equal to or greater than a predetermined plunger oil oil pressure required to maintain the plunger piston at the bottom of the plunger piston sealing chamber, and with the plunger piston maintained at the bottom of the plunger piston sealing chamber, the plunger compression chamber is closed but fluid communication is maintained from the plunger chamber supply passage through the plunger piston fuel oil opening to the check valve supply passage; (c) the method further includes supplying fuel oil to the intake valve fuel inlet and through the intake one-way valve and the plunger piston fuel opening to the check valve supply line at a first predetermined test fuel oil pressure, the first predetermined test fuel oil pressure being lower than the predetermined fuel oil pressure required to open the check valve; (d) the method further includes verifying that the supplied fuel oil is not leaking from the nozzle valve opening; method.

2. The injection valve under test has a hydraulic piston chamber for holding a hydraulic piston connected to the nozzle valve piston shutoff shaft, and a seal oil passage fluidly communicating with the plunger piston sealing chamber for sealing the plunger piston and fluidly communicating with the hydraulic piston chamber for sealing the hydraulic piston, the hydraulic piston being controlled by supplying control oil through a control oil supply passage to open and close the nozzle valve, and the control oil being supplied at a certain control oil pressure; The method includes a sealing step including supplying seal oil at a first seal oil hydraulic pressure to the plunger piston sealing chamber and the hydraulic piston chamber through the seal oil passage before supplying plunger oil in (b), However, the first seal oil pressure is a pressure equal to or greater than a predetermined seal oil pressure required to seal the plunger piston in the plunger piston sealing chamber and to seal the hydraulic piston in the hydraulic piston chamber. The method of claim 1.

3. The method of claim 2, wherein the predetermined seal oil pressure is in the range of 60 to 100 bar.

4. the injection valve under test is placed in a functional test valve holder; the function test valve holder holds a nozzle valve piston lift unit having a lift piston and a lift oil passage; the nozzle valve piston lift unit is arranged so that the lift piston engages with the nozzle valve piston shutoff shaft tip; Lift oil is supplied to the lift piston through the lift oil passage at a predetermined pressure, thereby supplying the predetermined lift pressure for maintaining the nozzle valve piston shutoff shaft in a raised position; the nozzle valve piston lift unit further includes a lift unit fuel oil leak path and a lift unit fuel oil outlet, the lift unit fuel oil leak path and the lift unit fuel oil outlet being in fluid communication with the nozzle valve opening, whereby fuel oil leaking from the nozzle valve opening leaks from the lift unit fuel oil outlet; The method according to any one of claims 1 to 3.

5. The method according to any one of claims 1 to 3, wherein the first test plunger oil pressure is in the range of 280 to 320 bar.

6. 4. The method according to claim 1, wherein the step of supplying plunger oil to the plunger piston in (b) includes a first step of slowly increasing the oil pressure of the supplied plunger oil to a first low initial oil pressure, and a step of increasing the oil pressure to the first test plunger oil oil pressure, wherein the first low initial oil pressure is in the range of 10 to 50 bar.

7. 4. The method of claim 1, wherein the first predetermined test fuel oil pressure in (c) is about 30 bar.

8. 4. A method according to any one of claims 1 to 3, comprising: (e) slowly increasing the fuel oil supply pressure to the suction valve fuel inlet until the check valve opens; (f) observing the pressure of the supplied fuel oil when a drop or stream of fuel oil emerges from the nozzle valve opening, thereby determining the opening pressure of the check valve; A method comprising:

9. 9. The method of claim 8, (g) releasing the fuel oil supply pressure to a pressure lower than the determined opening pressure of the check valve; (h) increasing the supply pressure of fuel oil to the suction valve fuel inlet until it reaches a pressure that is 3 to 5 bar lower than the determined opening pressure of the check valve; (i) checking whether the supplied fuel oil is leaking from the nozzle valve opening; A method comprising:

10. 4. A method according to any one of claims 1 to 3, comprising: removing the predetermined lift pressure from the tip of the nozzle valve piston shutoff shaft, causing the nozzle valve piston shutoff shaft to be pressed against the nozzle valve seat by the spring force of the nozzle valve spring, thereby closing the nozzle valve; supplying fuel oil to the intake valve fuel inlet and through the intake one-way valve and plunger piston fuel opening into the check valve supply line at a second predetermined test fuel oil pressure higher than the predetermined fuel oil pressure required to open the check valve; checking whether the supplied fuel oil is leaking from the nozzle valve opening; Including, method.

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