Electronically controlled diesel-ammonia dual-fuel injector

Abstract

An electronically controlled diesel-ammonia dual-fuel injector comprises a retaining assembly arranged in a retaining cap 14. The assembly includes an intermediate block 2, a metering orifice plate 17, a pilot-ignition control valve body 16, a solenoid valve body 15, an ammonia injection control valve body 4, an upper metering orifice plate 13, a lower metering orifice plate 12 and a nozzle 9 which are arranged from top to bottom. A solenoid control valve assembly 3 is arranged in the pilot-ignition control valve body, the solenoid valve body and the ammonia injection control valve body. A pilot control assembly 7 is arranged in the upper metering orifice plate and the lower metering orifice plate. An injection assembly 10 is arranged in the nozzle and comprises a pilot-ignition needle valve 8 sleeved outside an ammonia injection needle valve 11. An ammonia fuel pipeline 18 and a diesel pipeline 1 are arranged in the intermediate block and each passes through the pilot-ignition control valve body, the solenoid valve body, the ammonia injection control valve body, the upper metering orifice plate and the lower metering orifice plate sequentially, and then enter into the nozzle.

Description

[0001] The present disclosure relates to a fuel supply system for a dual-fuel engine, in particular to a dual-fuel injector. BACKGROUND

[0002] At present, the development of diesel engines is facing the double pressure caused by energy crisis and environmental pollution. On the one hand, it is necessary to continuously improve the performance of diesel engines so as to reduce fuel consumption; on the other hand, it is necessary to reduce nitrogen dioxide, PM, carbon monoxide and other harmful components contained in exhaust gas. In the field of ships, choosing suitable alternative fuels is an effective way to fundamentally solve the problem of carbon emissions.

[0003] As one of the most potential low-carbon alternative fuels, ammonia is expected to be widely used in the field of ship power in the future due to its high energy storage, mature production process, convenient storage and transportation. However, there is no mature ammonia fuel supply device at present, and ammonia fuel is difficult to bum as a single fuel due to its high self-ignition temperature, low calorific value and low flame propagation speed. Therefore, diesel pilot-ignition is needed to make up for the lack of combustion performance of the ammonia fuel. In addition, liquid ammonia is easy to vaporize at the low pressure, so the use of liquid ammonia as a servo fuel is easy to cause unstable injector control. SUMMARY

[0004] An objective of the present disclosure is to provide an electronically controlled diesel-ammonia dual-fuel injector capable of achieving the flexible switching between a single fuel injection mode and a dual-fuel injection mode.

[0005] The objective of the present disclosure is achieved through the following technical solution:

[0006] An electronically controlled diesel-ammonia dual-fuel injector includes a retaining cap and an assembly arranged in the retaining cap, where the assembly includes an intermediate block, a metering orifice plate, a pilot-ignition control valve body, a solenoid valve body, an ammonia injection control valve body, an upper metering orifice plate, a lower metering orifice plate, and a nozzle which are arranged from top to bottom. A solenoid control valve assembly is arranged in the pilot-ignition control valve body, the solenoid valve body and the ammonia injection control valve body. A pilot control assembly is arranged in the upper metering orifice plate and the lower metering orifice plate. An injection assembly is arranged in the nozzle, and the injection assembly includes an ammonia injection needle valve, and a pilot-ignition needle valve. The pilot-ignition needle valve is sleeved outside the ammonia injection needle valve. An ammonia fuel pipeline and a diesel pipeline are arranged in the intermediate block, and the ammonia fuel pipeline and the diesel pipeline respectively pass through the pilot-ignition control valve body, the solenoid valve body, the ammonia injection control valve body, the upper metering orifice plate and the lower metering orifice plate sequentially, and then enter into the nozzle.

[0007] The present disclosure may also include the following.

[0008] 1. The solenoid control valve assembly includes a pilot-ignition control valve, an ammonia injection control valve, a pilot-ignition electromagnet, and an ammonia injection electromagnet. The pilot-ignition control valve is arranged in the pilot-ignition control valve body, and a pilot-ignition armature is installed on a bottom of the pilot-ignition control valve. A separator is arranged in the solenoid valve body, the pilot-ignition electromagnet is installed above the separator, and the ammonia injection electromagnet is installed below the separator. The ammonia injection control valve is arranged in the ammonia injection control valve body, and an ammonia injection armature is installed on a top of the ammonia injection control valve. A pilot-ignition control valve return spring is installed in the pilot-ignition electromagnet, and the pilot-ignition armature and the separator are respectively located at both ends of the pilot-ignition control valve return spring. An ammonia injection control valve return spring is arranged in the ammonia injection electromagnet, and the separator and the ammonia injection armature are respectively located at both ends of the ammonia injection control return spring. A pilot-ignition oil return orifice is formed in the metering orifice plate, and a pilot-ignition sealing ball is installed at a position where the pilot-ignition oil return orifice is in contact with the pilot-ignition control valve. An ammonia injection oil return orifice is formed in the upper metering orifice plate, and an ammonia injection sealing ball is installed at a position where the ammonia injection oil return orifice is in contact with the ammonia injection control valve. A pilot-ignition return passage is arranged in the metering orifice plate, the pilot-ignition return passage is communicated with the pilot-ignition oil return orifice, and passes through the pilot-ignition control valve body, the solenoid valve body, the ammonia injection control valve body, the upper metering orifice plate, and the lower metering orifice plate in sequence.

[0009] 2. The pilot control assembly includes a pilot-ignition control chamber enclosed by the lower metering orifice plate, the nozzle and the pilot-ignition needle valve, and an ammonia injection control chamber enclosed by the lower metering orifice plate, the pilot-ignition needle valve and the ammonia injection needle valve. The pilot-ignition needle valve return spring is installed in the pilot-ignition control chamber, and the ammonia injection needle valve return spring is installed in the ammonia injection control chamber. An ammonia injection oil inlet orifice is formed in the upper metering orifice plate, and a pilot-ignition oil inlet orifice is formed in the lower metering orifice plate. The ammonia injection oil inlet orifice is communicated with the ammonia injection control chamber and the diesel pipeline, respectively. The pilot-ignition oil inlet orifice is communicated with the pilot-ignition control chamber and the diesel pipeline, respectively.

[0010] 3. A pilot-ignition injection orifice and an ammonia injection orifice are arranged at a bottom of the nozzle. The pilot-ignition injection orifice is located above the ammonia injection orifice, the pilot-ignition needle valve and the nozzle form an ammonia holding chamber and an oil holding chamber. A lower end of the pilot-ignition needle valve is machined into a conical surface and forms a conical surface seal with the pilot-ignition injection orifice. When the pilot-ignition needle valve is seated on its valve seat, the conical surface seal separates high-pressure fuel oil in the oil holding chamber from the pilot-ignition injection orifice. The ammonia injection needle valve forms a cylindrical surface seal with the ammonia injection orifice, a hollow portion is formed in the ammonia injection needle valve, and the nozzle below the ammonia injection needle valve forms a pressure chamber. An ammonia inlet hole is formed in the pilot-ignition needle valve, and the hollow portion is communicated with the ammonia inlet hole and the pressure chamber, respectively. The ammonia inlet hole is communicated with the ammonia holding chamber.

[0011] 4. When the electronically controlled diesel-ammonia dual-fuel is out of operation, a coil of the pilot-ignition electromagnet and a coil of the ammonia injection electromagnet are not electrified, the pilot-ignition control valve enables the pilot-ignition sealing ball to form a seal with a valve seat machined on the metering orifice plate under an action of a preload force of the pilot-ignition control valve return spring, and the ammonia injection control valve enables the ammonia injection sealing ball to form a seal with a valve seat machined on the upper metering orifice plate, under an action of a preload force of the ammonia injection control valve return spring. The high-pressure fuel oil enters the diesel pipeline and then is divided into two streams, one stream flows into the oil holding chamber at a lower end of the nozzle, and another stream flows to the pilot control assembly; the high-pressure fuel oil in the diesel pipeline enters the ammonia injection control chamber through an ammonia injection oil inlet hole and the ammonia injection oil inlet orifice, and enters the pilot-ignition control chamber through a pilot-ignition oil inlet hole and the pilot-ignition oil inlet orifice. The high-pressure fuel oil in the ammonia injection control chamber is introduced to a chamber below the ammonia injection sealing ball through an ammonia injection oil return orifice, and the high-pressure fuel oil in the pilot-ignition control chamber is introduced to a chamber above the pilot-ignition sealing ball through the pilot-ignition oil return passage and the pilot-ignition oil return orifice. The ammonia injection needle valve is at a lower limit position thereof under a joint action of the preload force of the ammonia injection needle valve return spring and a hydraulic pressure, and closes the ammonia injection orifice. The pilot-ignition needle valve is seated on a valve seat machined on the nozzle under a joint action of the preload force of the pilot-ignition needle valve return spring and a hydraulic pressure, and closes the pilot-ignition injection orifice.

[0012] 5. During diesel injection, the coil of the pilot-ignition electromagnet is electrified, the coil of the ammonia injection electromagnet is powered off, and an electromagnetic force received by the pilot-ignition armature and a hydraulic pressure acting on an upper end of the pilot-ignition sealing ball jointly overcome the preload force of the pilot-ignition control valve return spring, so as to drive the pilot-ignition control valve to move downwards. The pilot-ignition sealing ball moves downwards, the high-pressure fuel oil in the pilot-ignition control chamber enters a low-pressure oil circuit through the pilot-ignition oil return passage, the pilot-ignition oil return orifice, and a gap between the pilot-ignition sealing ball and a valve seat machined on the metering orifice plate. With a progress of an oil return process, a fuel oil pressure in the pilot-ignition control chamber decreases, and meanwhile, the high-pressure fuel oil in the diesel pipeline is used for supplement of fuel oil in the pilot-ignition control chamber through the pilot-ignition oil inlet hole and the pilot-ignition oil inlet orifice. A diameter of the pilot-ignition oil return orifice is larger than that of the pilot-ignition oil inlet orifice, the fuel oil pressure in the pilot-ignition control chamber gradually decreases until a hydraulic pressure at a lower end of the pilot-ignition needle valve is greater than a sum of a hydraulic pressure in the pilot-ignition control chamber and an elastic force of the pilot-ignition needle valve return spring, the pilot-ignition needle valve starts to be lifted, and the high-pressure fuel oil in the oil holding chamber is ejected from the pilot-ignition injection orifice.

[0013] After the diesel injection is over, the coil of the pilot-ignition electromagnet is powered off, the pilot-ignition control valve enables the pilot-ignition sealing ball to seat on the valve seat machined on the metering orifice plate under an action of an elastic force of the pilot-ignition control valve return spring, and the pilot-ignition control chamber does not return oil. The high-pressure fuel oil in the diesel pipeline enters the pilot-ignition control chamber through the pilot-ignition oil inlet hole and the pilot-ignition oil inlet orifice to recover the fuel oil pressure in the pilot-ignition control chamber, the pilot-ignition injection orifice is closed by the pilot-ignition needle valve under a joint action of the pilot-ignition needle valve return spring and a hydraulic pressure, and thus the fuel oil injection is stopped.

[0014] During ammonia fuel injection, the coil of the ammonia injection electromagnet is electrified, the coil of the pilot-ignition electromagnet is powered off, and an electromagnetic force received by the ammonia injection armature and a hydraulic pressure at a lower end of the ammonia injection sealing ball jointly overcome the preload force of the ammonia injection control valve return spring, so as to drive the ammonia injection control valve to move upwards. The ammonia injection sealing ball moves upwards, the high-pressure fuel oil in the ammonia injection control chamber enters a low-pressure oil circuit through the ammonia injection oil return orifice and a gap between the ammonia injection sealing ball and the valve seat machined on the upper metering orifice plate. With a progress of an oil return process, a fuel oil pressure in the ammonia injection control chamber decreases, and meanwhile, the high-pressure fuel oil in the diesel pipeline is used for supplement of the fuel oil in the ammonia injection control chamber through the ammonia injection oil inlet hole and the ammonia injection oil inlet orifice. A diameter of the ammonia injection oil return orifice is greater than that of the ammonia injection oil inlet orifice, the fuel oil pressure in the ammonia injection control chamber gradually decreases until a hydraulic pressure at a lower end of the ammonia injection needle valve is greater than a sum of a hydraulic pressure in the ammonia injection control chamber and an elastic force of the ammonia injection needle valve return spring, the ammonia injection needle valve starts to be lifted, and ammonia flowing through the ammonia fuel pipeline, the ammonia inlet hole and the pressure chamber is ejected from the ammonia injection orifice.

[0015] After the ammonia fuel injection is over, the coil of the ammonia injection electromagnet is powered off, the ammonia injection control valve enables the ammonia injection sealing ball to seat on the valve seat machined on the upper metering orifice plate under an action of an elastic force of the ammonia injection control valve return spring, and the ammonia injection control chamber does not return oil. The high-pressure fuel oil in the diesel pipeline enters the ammonia injection control chamber through the ammonia injection oil inlet hole and the ammonia injection oil inlet orifice to gradually recover the fuel oil pressure in the ammonia injection control chamber, the ammonia injection orifice is closed by the ammonia injection needle valve under a joint action of the elastic force of the ammonia injection needle valve return spring and a hydraulic pressure, and thus the ammonia fuel injection is stopped.

[0016] 7 When the electronically controlled diesel-ammonia dual-fuel injector adopts a diesel pilot-ignition-ammonia main injection mode, diesel is injected first, enters a cylinder and is compressed and ignited to make a temperature and pressure of a fuel gas in the cylinder rise, and then liquid ammonia is injected.

[0017] The present disclosure has the advantages that the diesel is used as the servo oil to achieve pilot control of ammonia fuel injection, and a diesel pilot-ignition mode is used to assist ammonia fuel combustion, so that high-pressure and stable injection of the ammonia fuel can be achieved, and the combustion efficiency of the ammonia fuel in a cylinder is improved, and thus the power performance and emission performance of an engine are improved. In addition, the flexible switching between a single fuel injection mode and a dual fuel injection mode can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. lisa schematic diagram of a structure in accordance with the present disclosure.

[0019] FIG. 2 is a structural schematic diagram of a solenoid control valve assembly;

[0020] FIG. 3 is a structure schematic diagram of a pilot control assembly;

[0021] FIG. 4 is a structural schematic diagram of an injection assembly. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The present disclosure is further described in detail below with reference to the accompanying drawings.

[0023] Referring to FIGS. 1-4, the electronically controlled diesel-ammonia dual-fuel injector of the present disclosure includes a diesel pipeline 1, an intermediate block 2, a solenoid control valve assembly 3, an ammonia injection control valve body 4, an ammonia injection oil inlet hole 5, a pilot-ignition oil inlet hole 6, a pilot control assembly 7, a pilot-ignition needle valve 8, a nozzle 9, an injection assembly 10, an ammonia injection needle valve 11, a lower metering orifice plate 12, an upper metering orifice plate 13, a retaining cap 14, a solenoid valve body 15, a pilot-ignition control valve body 16, a metering orifice plate 17, and an ammonia fuel pipeline 18. The intermediate block 2, the metering orifice plate 17, the pilot-ignition control valve body 16, the solenoid valve body 15, the ammonia injection control valve body 4, the upper metering orifice plate 13, the lower metering orifice plate 12 and the nozzle 9 are installed from top to bottom and connected together by locating pins. The solenoid control valve assembly 3, the pilot control assembly 7 and the injection assembly 10 are installed in an injector from top to bottom, and the retaining cap 14 and the intermediate block 2 are fastened together by threads. The lower middle portion of the ammonia injection needle valve 11 is hollow, and the pilot-ignition needle valve 8 is of a hollow structure. The ammonia injection needle valve 11 is installed inside the pilot-ignition needle valve 8. The ammonia injection needle valve 11 forms a moving coupling with the pilot-ignition needle valve 8, and the pilot-ignition needle valve 8 forms a moving coupling with the nozzle 9.

[0024] Liquid ammonia enters the injection assembly 10 through the ammonia fuel pipeline 18. The high-pressure fuel oil flows through the pilot control assembly 7 and the injection assembly 10 in an injector through the diesel pipeline 1. High-pressure fuel oil flowing into the pilot control assembly 7 enters an ammonia injection control chamber 35 through the ammonia injection oil inlet hole 5 and an ammonia injection oil inlet orifice 31, and enters a pilot-ignition control chamber 36 through the pilot-ignition oil inlet hole 6 and a pilot-ignition oil inlet orifice 32. The fuel oil flowing into the injection assembly 10 enters an oil holding chamber 38 and fills a chamber around the pilot-ignition needle valve 8.

[0025] A pilot-ignition electromagnet 21 and an ammonia injection electromagnet 22 are symmetrically installed from up to down, and the pilot-ignition electromagnet 21 is installed above the ammonia injection electromagnet 22. A pilot-ignition armature 29 is installed above the pilot-ignition electromagnet 21 and on a lower end of the pilot-ignition control valve 20. A pilot-ignition control valve return spring 28 is installed between the pilot-ignition armature 29 and the solenoid valve body 15. A pilot-ignition sealing ball 19 is arranged on an upper end of the pilot-ignition control valve 20 to form a seal portion with a valve seat machined on the metering orifice plate 17. A pilot-ignition oil return orifice 30 is arranged above the seal portion and machined on an upper middle portion of the metering orifice plate 17. The pilot-ignition oil return orifice 30 is communicated with a chamber of the pilot control assembly 7 through a pilot-ignition oil return passage 27. An ammonia injection armature 26 is installed below the ammonia injection electromagnet 22 and on an upper end of the ammonia injection control valve 24. An ammonia injection control valve return spring 23 is installed between the solenoid valve body 15 and the ammonia injection armature 26. An ammonia injection sealing ball 25 is installed on a lower end of the ammonia injection control valve 24 to form a seal portion with a valve seat machined on the upper metering orifice plate 13.

[0026] The ammonia injection needle valve 11, the pilot-ignition needle valve 8 and the T-shaped lower metering orifice plate 12 form the ammonia injection control chamber 35 in a shape of a cylinder, and the pilot-ignition needle valve 8, the nozzle 9 and the T-shaped lower measuring orifice plate 12 form the pilot-ignition control chamber 36 in a shape of a cylinder. The ammonia injection control chamber 35 is communicated with the diesel pipeline 1 through the ammonia injection oil inlet orifice 31 and the ammonia injection oil inlet hole 5, and is communicated with a chamber below the ammonia injection sealing ball 25 through an ammonia injection oil return orifice 37. The pilot-ignition control chamber 36 is communicated with the diesel pipeline 1 through a pilot-ignition oil inlet orifice 32 and the pilot-ignition oil inlet hole 6, and is communicated with a chamber above the pilot-ignition sealing ball 19 through the pilot-ignition oil return passage 27 and the pilot-ignition oil return orifice 30. The ammonia injection needle valve 11 and the pilot-ignition needle valve 8 are respectively installed below the ammonia injection control chamber 35 and the pilot-ignition control chamber 36. An ammonia injection needle valve return spring 34 is installed between the ammonia injection needle valve 11 and the lower metering orifice plate 12 and a pilot-ignition needle valve return spring 33 is installed between the pilot-ignition needle valve 8 and the lower metering orifice plate 12. A lower end of the pilot-ignition needle valve 8 is machined into a conical surface to form a seal portion with the nozzle 9, so as to separate high-pressure fuel oil in the oil holding chamber 38 from a gas mixture in a cylinder and a pilot-ignition injection orifice 39. The ammonia injection needle valve 11 forms a cylindrical seal portion with the nozzle 9, so as to separate ammonia fuel in the pressure chamber 40 from a gas mixture in an ammonia injection orifice 41. An ammonia inlet hole 42 is machined in the middle portions of the pilot-ignition needle valve 8 and the ammonia injection needle valve 11 to communicate the ammonia fuel pipeline 18 with a hollow chamber in the ammonia injection needle valve 11 and the pressure chamber 40.

[0027] The electronically controlled diesel-ammonia dual-fuel injector of the present disclosure controls the injection of diesel and the injection of ammonia respectively through dual solenoid valves, so a diesel injection process and an ammonia injection process of the injector are independent. The present disclosure not only can achieve an injection mode of diesel pilot-ignition-ammonia main injection, but also can employ a single fuel injection mode of only injecting diesel or only injecting liquid ammonia. The following mainly introduces the single fuel injection mode, and its working process is as follows:

[0028] When the injector is out of operation, coils of the pilot-ignition electromagnet 21 and the ammonia injection electromagnet 22 are not electrified, the pilot-ignition control valve 20 and the ammonia injection control valve 24, under the action of preload forces of the pilot-ignition control valve return spring 28 and the ammonia injection control valve return spring 23, enable the pilot-ignition sealing ball 19 and the ammonia injection sealing ball 25 to form seals with valve seats machined on the metering orifice plate 17 and the upper metering orifice plate 13, respectively. The high-pressure fuel oil enters a communicating chamber in the injector through the diesel pipeline 1 and then is divided into two streams, one stream flows into the oil holding chamber 38 at a lower end of the nozzle 9, and the other stream flows to the pilot control assembly 7. The high-pressure fuel oil in the diesel pipeline 1 enters the ammonia injection control chamber 35 through the ammonia injection oil inlet hole 5 and the ammonia injection oil inlet orifice 31, and enters the pilot-ignition control chamber 36 through the pilot-ignition oil inlet hole 6 and the pilot-ignition oil inlet orifice 32. The high-pressure fuel oil in the ammonia injection control chamber 35 is introduced into a chamber below the ammonia injection sealing ball 25 through the ammonia injection oil return orifice 37, and the high-pressure fuel oil in the pilot-ignition control chamber 36 is introduced into a chamber above the pilot-ignition sealing ball 19 through the pilot-ignition oil return passage 27 and the pilot-ignition oil return orifice 30. The ammonia injection needle valve 11 is at its lower limit position under the action of the preload force of the ammonia injection needle valve return spring 34 and a hydraulic pressure, and closes the ammonia injection orifice 41. The pilot-ignition needle valve 8 is seated on a valve seat machined on the nozzle 9 under the action of the preload force of the pilot-ignition needle valve return spring 33 and the hydraulic pressure, and closes the pilot-ignition injection orifice 39.

[0029] When the injector is used for diesel injection, the coil of the pilot-ignition electromagnet 21 is electrified, the coil of the ammonia injection electromagnet 22 is powered off, and an electromagnetic force received by the pilot-ignition armature 29 and the hydraulic pressure acting on an upper end of the pilot-ignition sealing ball 19 jointly overcome the preload force of the pilot-ignition control valve return spring 28, so as to drive the pilot-ignition control valve 20 to move downwards. The pilot-ignition sealing ball 19 moves downwards, the high-pressure fuel oil in the pilot-ignition control chamber 36 enters a low-pressure oil circuit through the pilot-ignition oil return passage 27, the pilot-ignition oil return orifice 30, and a gap between the pilot-ignition sealing ball 19 and the valve seat machined on the metering orifice plate 17. With the progress of an oil return process, a fuel oil pressure in the pilot-ignition control chamber 36 decreases, and meanwhile, the high-pressure fuel oil in the diesel pipeline 1 is used for supplement of the fuel oil in the pilot-ignition control chamber 36 through the pilot-ignition oil inlet hole 6 and the pilot-ignition oil inlet orifice 32. As a diameter of the pilot-ignition oil return orifice 30 is larger than that of the pilot-ignition oil inlet orifice 32, a fuel oil pressure in the pilot-ignition control chamber 36 continues to decrease until a hydraulic pressure at a lower end of the pilot-ignition needle valve 8 is greater than the sum of a hydraulic pressure in the pilot-ignition control chamber 36 and an elastic force of the pilot-ignition needle valve return spring 33, the pilot-ignition needle valve 8 starts to be lifted, and the high-pressure fuel oil in the oil holding chamber 38 is ejected from the pilot-ignition injection orifice 39.

[0030] After the fuel oil injection is over, the coil of the pilot-ignition electromagnet 21 is powered off, the pilot-ignition control valve 20 enables the pilot-ignition sealing ball 19 to seat on the valve seat machined on the metering orifice plate 17 under the action of the elastic force of the pilot-ignition control valve return spring 28, and the pilot-ignition control chamber 36 does not return oil. The high-pressure fuel oil in the diesel pipeline 1 enters the pilot-ignition control chamber 36 through the pilot-ignition oil inlet hole 6 and the pilot-ignition oil inlet orifice 32 to gradually recover the fuel oil pressure in the pilot-ignition control chamber 36, the pilot-ignition injection orifice 39 is closed by the pilot-ignition needle valve 8 under the action of the pilot-ignition needle valve return spring 33 and the hydraulic pressure, and thus the fuel oil injection is stopped.

[0031] When the injector is used for ammonia fuel injection, the coil of the ammonia injection electromagnet 22 is electrified, the coil of the pilot-ignition electromagnet 21 is powered off, and an electromagnetic force received by the ammonia injection armature 26 and a hydraulic pressure acting on a lower end of the ammonia injection sealing ball 25 jointly overcome the preload force of the ammonia injection control valve return spring 23, so as to drive the ammonia injection control valve 24 to move upwards. The ammonia injection sealing ball 25 moves upwards, the high-pressure fuel oil in the ammonia injection control chamber 35 enters a low-pressure oil circuit through the ammonia injection oil return orifice 37 and a gap between the ammonia injection sealing ball 25 and the valve seat machined on the upper metering orifice plate 13. With the progress of an oil return process, a fuel oil pressure in the ammonia injection control chamber 35 decreases, and meanwhile, the high-pressure fuel oil in the diesel pipeline 1 is used for supplement of the fuel oil in the ammonia injection control chamber 35 through the ammonia injection oil inlet hole 5 and the ammonia injection oil inlet orifice 31. As a diameter of the ammonia injection oil return orifice 37 is greater than that of the ammonia injection oil inlet orifice 31, the fuel oil pressure in the ammonia injection control chamber 35 continues to decrease until the hydraulic pressure at a lower end of the ammonia injection needle valve 11 is greater than the sum of the hydraulic pressure in the ammonia injection control chamber 35 and an elastic force of the ammonia injection needle valve return spring 34, the ammonia injection needle valve 11 starts to be lifted, and ammonia flowing through the ammonia fuel pipeline 18, the ammonia inlet hole 42 and the pressure chamber 40 is ejected from the ammonia injection orifice 41.

[0032] After the ammonia injection is over, the coil of the ammonia injection electromagnet 22 is powered off, the ammonia injection control valve 24 enables the ammonia injection sealing ball 25 to seat on the valve seat machined on the upper metering orifice plate 13 under the action of the elastic force of the ammonia injection control valve return spring 23, and the ammonia injection control chamber 35 does not return oil. The high-pressure fuel oil in the diesel pipeline 1 enters the ammonia injection control chamber 35 through the ammonia injection oil inlet hole 5 and the ammonia injection oil inlet orifice 31 to gradually recover the fuel oil pressure in the ammonia injection control chamber 35, the ammonia injection orifice 41 is closed by the ammonia injection needle valve 11 under the action of the elastic force of the ammonia injection needle valve return spring 34 and the hydraulic pressure, and thus the ammonia fuel injection is stopped.

[0033] When the injector adopts a diesel pilot-ignition-ammonia main injection mode, the diesel is injected first, enters a cylinder and then is compressed and ignited to make a temperature and pressure of a fuel gas in the cylinder rise, and then liquid ammonia is injected. As the combustion of the diesel provides a good environment for the combustion and flame propagation of liquid ammonia, the combustion efficiency of the liquid ammonia is improved.

Claims

1. An electronically controlled diesel-ammonia dual-fuel injector, comprising a retaining cap and an assembly arranged in the retaining cap, wherein the assembly comprises an intermediate block, a metering orifice plate, a pilot-ignition control valve body, a solenoid valve body, an ammonia injection control valve body, an upper metering orifice plate, a lower metering orifice plate, and a nozzle which are arranged from top to bottom; a solenoid control valve assembly is arranged in the pilot-ignition control valve body, the solenoid valve body and the ammonia injection control valve body; a pilot control assembly is arranged in the upper metering orifice plate and the lower metering orifice plate, an injection assembly is arranged in the nozzle, and the injection assembly comprises an ammonia injection needle valve, and a pilot-ignition needle valve; the pilot-ignition needle valve is sleeved outside the ammonia injection needle valve; an ammonia fuel pipeline and a diesel pipeline are arranged in the intermediate block; and the ammonia fuel pipeline and the diesel pipeline respectively pass through the pilot-ignition control valve body, the solenoid valve body, the ammonia injection control valve body, the upper metering orifice plate and the lower metering orifice plate sequentially, and then enter into the nozzle.

2. The electronically controlled diesel-ammonia dual-fuel injector according to claim 1, wherein the solenoid control valve assembly comprises a pilot-ignition control valve, an ammonia injection control valve, a pilot-ignition electromagnet, and an ammonia injection electromagnet; the pilot-ignition control valve is arranged in the pilot-ignition control valve body, a pilot-ignition armature is installed on a bottom of the pilot-ignition control valve, a separator is arranged in the solenoid valve body, the pilot-ignition electromagnet is installed above the separator, and the ammonia injection electromagnet is installed below the separator; the ammonia injection control valve is arranged in the ammonia injection control valve body, and an ammonia injection armature is installed on a top of the ammonia injection control valve; a pilot-ignition control valve return spring is installed in the pilot-ignition electromagnet, and the pilot-ignition armature and the separator are respectively located at both ends of the pilot-ignition control valve return spring; an ammonia injection control valve return spring is arranged in the ammonia injection electromagnet, and the separator and the ammonia injectionarmature are respectively located at both ends of the ammonia injection control return spring; a pilot-ignition oil return orifice is formed in the metering orifice plate; a pilot-ignition sealing ball is installed at a position where the pilot-ignition oil return orifice is in contact with the pilot-ignition control valve; an ammonia injection oil return orifice is formed in the upper metering orifice plate, an ammonia injection sealing ball is installed at a position where the ammonia injection oil return orifice is in contact with the ammonia injection control valve; a pilot-ignition return passage is arranged in the metering orifice plate, the pilot-ignition return passage is communicated with the pilot-ignition oil return orifice, and passes through the pilot-ignition control valve body, the solenoid valve body, the ammonia injection control valve body, the upper metering orifice plate, and the lower metering orifice plate in sequence.

3. The electronically controlled diesel-ammonia dual-fuel injector according to claim 2, wherein the pilot control assembly comprises a pilot-ignition control chamber enclosed by the lower metering orifice plate, the nozzle and the pilot-ignition needle valve, and an ammonia injection control chamber enclosed by the lower metering orifice plate, the pilot-ignition needle valve and the ammonia injection needle valve; the pilot-ignition needle valve return spring is installed in the pilot-ignition control chamber, and the ammonia injection needle valve return spring is installed in the ammonia injection control chamber; an ammonia injection oil inlet orifice is formed in the upper metering orifice plate, and a pilot-ignition oil inlet orifice is formed in the lower metering orifice plate; the ammonia injection oil inlet orifice is communicated with the ammonia injection control chamber and the diesel pipeline, respectively; and the pilot-ignition oil inlet orifice is communicated with the pilot-ignition control chamber and the diesel pipeline, respectively.

4. The electronically controlled diesel-ammonia dual-fuel injector according to claim 3, wherein a pilot-ignition injection orifice and an ammonia injection orifice are arranged at a bottom of the nozzle; the pilot-ignition injection orifice is located above the ammonia injection orifice, the pilot-ignition needle valve and the nozzle form an ammonia holding chamber and an oil holding chamber, a lower end of the pilot-ignition needle valve is machined into a conical surface and forms a conical surface seal with the pilot-ignition injection orifice, and when the pilot-ignition needle valve is seated on its valve seat, the conical surface seal separates high-pressure fuel oil in the oil holding chamber from the pilot-ignition injection orifice; theammonia injection needle valve forms a cylindrical surface seal with the ammonia injection orifice, a hollow portion is formed in the ammonia injection needle valve, and the nozzle below the ammonia injection needle valve forms a pressure chamber; an ammonia inlet hole is formed in the pilot-ignition needle valve, and the hollow portion is communicated with the ammonia inlet hole and the pressure chamber, respectively; and the ammonia inlet hole is communicated with the ammonia holding chamber.

5. The electronically controlled diesel-ammonia dual-fuel injector according to claim 4, wherein when the electronically controlled diesel-ammonia dual-fuel injector is out of operation, a coil of the pilot-ignition electromagnet and a coil of the ammonia injection electromagnet are not electrified, the pilot-ignition control valve enables the pilot-ignition sealing ball to form a seal with a valve seat machined on the metering orifice plate under an action of a preload force of the pilot-ignition control valve return spring, and the ammonia injection control valve enables the ammonia injection sealing ball to form a seal with a valve seat machined on the upper metering orifice plate under an action of a preload force of the ammonia injection control valve return spring, the high-pressure fuel oil enters the diesel pipeline and then is divided into two streams, wherein one stream flows into the oil holding chamber at a lower end of the nozzle, and another stream flows to the pilot control assembly; the high-pressure fuel oil in the diesel pipeline enters the ammonia injection control chamber through an ammonia injection oil inlet hole and the ammonia injection oil inlet orifice, and enters the pilot-ignition control chamber through a pilot-ignition oil inlet hole and the pilot-ignition oil inlet orifice; the high-pressure fuel oil in the ammonia injection control chamber is introduced to a chamber below the ammonia injection sealing ball through the ammonia injection oil return orifice, the high-pressure fuel oil in the pilot-ignition control chamber is introduced to a chamber above the pilot-ignition sealing ball through a pilot-ignition oil return passage and the pilot-ignition oil return orifice; the ammonia injection needle valve is at a lower limit position thereof under a joint action of the preload force of the ammonia injection needle valve return spring and a hydraulic pressure, and closes the ammonia injection orifice; and the pilot-ignition needle valve is seated on a valve seat machined on the nozzle under a joint action of the preload force of the pilot-ignition needle valve return spring and a hydraulic pressure, and closes the pilot-ignition injection orifice.

6. The electronically controlled diesel-ammonia dual-fuel injector according to claim 4,wherein during diesel injection, the coil of the pilot-ignition electromagnet is electrified, the coil of the ammonia injection electromagnet is powered off, an electromagnetic force received by the pilot-ignition armature and a hydraulic pressure acting on an upper end of the pilot-ignition sealing ball jointly overcome the preload force of the pilot-ignition control valve return spring, so as to drive the pilot-ignition control valve to move downwards, the pilot-ignition sealing ball moves downwards, the high-pressure fuel oil in the pilot-ignition control chamber enters a low-pressure oil circuit through the pilot-ignition oil return passage, the pilot-ignition oil return orifice, and a gap between the pilot-ignition sealing ball and a valve seat machined on the metering orifice plate; with a progress of an oil return process, a fuel oil pressure in the pilot-ignition control chamber decreases; meanwhile, the high-pressure fuel oil in the diesel pipeline is used for supplement of fuel oil in the pilot-ignition control chamber through the pilot-ignition oil inlet hole and the pilot-ignition oil inlet orifice; a diameter of the pilot-ignition oil return orifice is larger than that of the pilot-ignition oil inlet orifice, the fuel oil pressure in the pilot-ignition control chamber gradually decreases until a hydraulic pressure at a lower end of the pilot-ignition needle valve is greater than a sum of a hydraulic pressure in the pilot-ignition control chamber and an elastic force of the pilot-ignition needle valve return spring, the pilot-ignition needle valve starts to be lifted, and the high-pressure fuel oil in the oil holding chamber is ejected from the pilot-ignition injection orifice;after the diesel injection is over, the coil of the pilot-ignition electromagnet is powered off, the pilot-ignition control valve enables the pilot-ignition sealing ball to seat on the valve seat machined on the metering orifice plate under an action of an elastic force of the pilot-ignition control valve return spring, and the pilot-ignition control chamber does not return oil; the high-pressure fuel oil in the diesel pipeline enters the pilot-ignition control chamber through the pilot-ignition oil inlet hole and the pilot-ignition oil inlet orifice to recover the fuel oil pressure in the pilot-ignition control chamber, the pilot-ignition injection orifice is closed by the pilot-ignition needle valve under a joint action of the pilot-ignition needle valve return spring and a hydraulic pressure, and thus the fuel oil injection is stopped.

7. The electronically controlled diesel-ammonia dual-fuel injector according to claim 4, wherein during ammonia fuel injection, the coil of the ammonia injection electromagnet is electrified, the coil of the pilot-ignition electromagnet is powered off, an electromagnetic forcereceived by the ammonia injection armature and a hydraulic pressure at a lower end of the ammonia injection sealing ball jointly overcome the preload force of the ammonia injection control valve return spring, so as to drive the ammonia injection control valve to move upwards; the ammonia injection sealing ball moves upwards, the high-pressure fuel oil in the ammonia injection control chamber enters a low-pressure oil circuit through the ammonia injection oil return orifice and a gap between the ammonia injection sealing ball and the valve seat machined on the upper metering orifice plate; with a progress of an oil return process, a fuel oil pressure in the ammonia injection control chamber decreases, and meanwhile, the high-pressure fuel oil in the diesel pipeline is used for supplement of fuel oil in the ammonia injection control chamber through the ammonia injection oil inlet hole and the ammonia injection oil inlet orifice; a diameter of the ammonia injection oil return orifice is greater than that of the ammonia injection oil inlet orifice, the fuel oil pressure in the ammonia injection control chamber gradually decreases until a hydraulic pressure at a lower end of the ammonia injection needle valve is greater than a sum of a hydraulic pressure in the ammonia injection control chamber and an elastic force of the ammonia injection needle valve return spring, the ammonia injection needle valve starts to be lifted, and ammonia flowing through the ammonia fuel pipeline, the ammonia inlet hole and the pressure chamber is ejected from the ammonia injection orifice;after the ammonia fuel injection is over, the coil of the ammonia injection electromagnet is powered off, the ammonia injection control valve enables the ammonia injection sealing ball to seat on the valve seat machined on the upper metering orifice plate under an action of an elastic force of the ammonia injection control valve return spring, and the ammonia injection control chamber does not return oil; the high-pressure fuel oil in the diesel pipeline enters the ammonia injection control chamber through the ammonia injection oil inlet hole and the ammonia injection oil inlet orifice to gradually recover the fuel oil pressure in the ammonia injection control chamber, the ammonia injection orifice is closed by the ammonia injection needle valve under a joint action of the elastic force of the ammonia injection needle valve return spring and a hydraulic pressure, and thus the ammonia fuel injection is stopped.

8. The electronically controlled diesel-ammonia dual-fuel injector according to claim 4, wherein when the electronically controlled diesel-ammonia dual-fuel injector adopts a diesel pilot-ignition-ammonia main injection mode, diesel is injected first, enters a cylinder and is compressed and ignited to make a temperature and pressure of a fuel gas in the cylinder rise, andthen liquid ammonia is injected.

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