Precise electric control injection diesel pile driver

Abstract

The application discloses a diesel pile driver with precise electric control fuel injection, which is provided with an electric control fuel system and an electric control unit on a piston, and the outer side of the piston is provided with a position sensor one and a position sensor two; the electric control fuel system comprises a fuel pump assembly, an oil injection nozzle assembly and a two-position three-way electromagnetic valve, the oil outlet of the fuel pump assembly is connected with the pressure oil port P of the two-position three-way electromagnetic valve, the working oil port A of the two-position three-way electromagnetic valve is connected with the oil inlet of the oil injection nozzle assembly through a switch electromagnetic valve, and the working oil port A of the two-position three-way electromagnetic valve is also connected with a pressure sensor; the oil return port T of the two-position three-way electromagnetic valve is connected with an oil tank; and the electric control unit is electrically connected with the two-position three-way electromagnetic valve, the switch electromagnetic valve, a common rail pipe oil return electromagnetic valve and the pressure sensor. The diesel pile driver can not only realize the electric control of the diesel hammer pile driver, but also realize the precise control of fuel injection pressure, injection timing and fuel injection quantity, effectively improves the combustion of the pile driver and improves the pile driving efficiency.

Description

Technical Field

[0001] This invention relates to a pile driving machine for foundation construction in building engineering, and more particularly to a guide rod type diesel hammer pile driver that can precisely control fuel injection pressure, injection timing and injection volume. Background Technology

[0002] As a type of pile driving machinery with simple structure and convenient maintenance, the guide rod type diesel pile driver is widely used in the construction of various types of piles such as wooden piles, metal piles, precast concrete piles, lime-soil piles, cast-in-place piles, and rammed piles. Compared with hydraulic hammer pile drivers, diesel pile drivers have lower costs and are less likely to damage piles, which gives them a higher market share.

[0003] However, existing diesel hammer pile drivers suffer from low fuel injection pressure and inflexible injection timing, resulting in poor fuel atomization and incomplete combustion in the cylinder. This leads to excessive black smoke during operation and makes the nozzles prone to dripping and leaking, easily causing carbon buildup and nozzle blockage. With increasingly stringent emission regulations for non-road machinery, the use of diesel hammer pile drivers is significantly restricted. Furthermore, existing diesel hammer pile drivers require workers to manually adjust fuel supply by pulling levers based on experience to adapt to different working conditions. This not only increases labor costs but also heavily relies on workers' engineering experience, hindering the widespread adoption of diesel hammer pile drivers. Against this backdrop, this invention designs a precision electronic fuel injection diesel pile driver, providing a feasible path for the electrification of diesel hammer pile drivers. Summary of the Invention

[0004] The purpose of this invention is to provide a diesel pile driver with precise electronic fuel injection, which not only enables the electronic control of the diesel hammer pile driver, but also enables precise control of fuel injection pressure, injection timing and injection quantity, so as to improve the combustion of the pile driver and reduce the emission of pollutants such as carbon soot.

[0005] The objective of this invention is achieved as follows:

[0006] This invention discloses a precision electronically controlled fuel injection diesel pile driver, comprising two parallel guide rods. A top crossbeam is fixedly installed at the upper end of the guide rods, and a piston is fixedly connected to the lower end of the guide rods. A cylinder hammer is slidably supported on the guide rods. An electronically controlled fuel system and an electronic control unit are installed on the piston. A position sensor 1 and a position sensor 2 are installed on the outer side of the piston. The electronically controlled fuel system includes a fuel pump assembly, a fuel injector assembly, and a two-position three-way solenoid valve. The fuel outlet of the fuel pump assembly is connected to the pressure port P of the two-position three-way solenoid valve. The working port A of the two-position three-way solenoid valve is connected to the fuel inlet of the fuel injector assembly via a switching solenoid valve. The working port A of the two-position three-way solenoid valve is also connected to the fuel tank via a common rail return solenoid valve. A pressure sensor is also connected to the working port A of the two-position three-way solenoid valve. The return port T of the two-position three-way solenoid valve is connected to the fuel tank. The electronic control unit is electrically connected to the two-position three-way solenoid valve, the switching solenoid valve, the common rail return solenoid valve, and the pressure sensor.

[0007] Preferably, the working port A of the two-position three-way solenoid valve is connected to the oil tank via a pressure relief valve, which is an overflow valve.

[0008] Preferably, the working port A of the two-position three-way solenoid valve is connected to the inlet of the fuel injector assembly via a switching solenoid valve and a check valve in sequence.

[0009] Preferably, the switching solenoid valve and the common rail return solenoid valve are two-position two-way solenoid valves, and the pressure sensor is a piezoresistive pressure sensor or a piezoelectric pressure sensor.

[0010] Preferably, the position sensor one and the position sensor two are fixedly mounted on a sensor bracket, which is fixedly connected to the top crossbeam and / or the piston.

[0011] Preferably, the fuel pump assembly's outlet is connected to the pressure port P of the two-position three-way solenoid valve via the inlet pipe of the two-position three-way solenoid valve, the working port A of the two-position three-way solenoid valve is connected to the common rail inlet via the outlet pipe of the two-position three-way solenoid valve, and the return port of the two-position three-way solenoid valve is connected to the fuel tank via the return pipe of the two-position three-way solenoid valve.

[0012] Preferably, the piston includes a piston seat and a piston body that are integrally connected, the oil tank is fixed on the piston seat, and piston rings are fitted on the cylindrical surface of the piston body.

[0013] Preferably, the position sensor is on the same plane as the uppermost piston ring of the piston body.

[0014] Preferably, the fuel pump assembly includes a plunger and a tappet movably supported on the pump body, one end of a crank hinged to the piston contacts the tappet, and the other end of the crank corresponds to an impact pin, which is fixedly mounted on the cylinder hammer.

[0015] Preferably, the position sensor two is on the same plane as the contact point between the impact pin and the crank.

[0016] Compared with existing guide rod type diesel pile drivers, the advantages of this invention are:

[0017] 1. This invention uses two position sensors to detect the motion characteristics of the cylinder hammer and transmits signals to the electronic control unit (ECU) to determine whether the cylinder hammer is in an ascending or descending state and the operating condition of the pile driver, thereby selecting the appropriate spraying strategy.

[0018] 2. The check valve has a certain opening pressure, which can effectively prevent oil dripping and leakage.

[0019] 3. The combination of common rail, two-position three-way solenoid valve and switching solenoid valve can obtain higher and more stable injection pressure and proper injection timing, which can effectively improve the in-cylinder air-fuel mixture level, enhance combustion, reduce the emission levels of pollutants such as NOx and soot, and increase the maximum burst pressure of the piling machine, thereby improving piling efficiency.

[0020] 4. The electronic control unit (ECU) can control the injection timing and duration by adjusting the pulse width of the switching solenoid valve, and control the injection pressure by adjusting the state of the two-position three-way solenoid valve. It can implement different injection strategies to adapt the pile driver to different working conditions, and it is more accurate, flexible and economical than manual adjustment of oil supply.

[0021] 5. The electronic fuel control system of the present invention can achieve decoupled control of the fuel injection process and the fuel supply process.

[0022] Instruction manual illustrations

[0023] Figure 1 The diagram shown is a front view of a specific embodiment of the diesel pile driver with precise electronic fuel injection according to the present invention.

[0024] Figure 2 for Figure 1 A schematic diagram of the rear structure of the embodiment shown;

[0025] Figure 3 for Figure 1 The schematic diagram of the electronically controlled fuel system in the embodiment shown is as follows;

[0026] Figure 4 yes Figure 3 The diagram shown is the control circuit diagram of the electronic fuel system.

[0027] Figure 5 yes Figure 3 Cross-sectional view of the fuel pump assembly. Detailed Implementation

[0028] The invention will be further described in detail below with reference to the accompanying drawings:

[0029] like Figure 1 , Figure 2 The diesel pile driver shown is a precision electronically controlled fuel injection system. It includes a sensor bracket 1, a position sensor 1 2, a position sensor 2 3, a guide rod 4, a landing gear 5, a top crossbeam 6, a pulley 7, a hammer 8, a piston 9, a crank 10, an impact pin 11, an electronically controlled fuel system 12, a pile cap 13, a fuel tank 14, and an electronic control unit 15. The top crossbeam 6 is fixed to the top of the guide rod 4. The pulley 7 and the landing gear 5 are connected by a landing gear shaft 16 and can slide vertically along the guide rod 4. The landing gear 5 is equipped with a hammer hook 17 and a release rod 18. The hammer 8 is located below the landing gear 5 and can also slide vertically along the guide rod 4. The crank 10 is mounted on the fuel tank 14 via an eccentric shaft 19. Below the hammer 8 is the piston 9, which includes a piston seat and a piston body integrated into one unit. The fuel tank 14 is fixed to the piston seat, and piston rings are fitted onto the cylindrical surface of the piston body. Piston 9, electronic control unit 15, fuel tank 14, and post cap 13 are fixed together. The upper and lower ends of sensor bracket 1 are fixed to top crossbeam 6 and fuel tank 14 respectively. Position sensor 2 and position sensor 3 are arranged sequentially from top to bottom on sensor bracket 1. Position sensor 2 is horizontally aligned with the first piston ring of piston 9, meaning position sensor 2 and the uppermost piston ring of piston 9 are on the same plane. Position sensor 3 is horizontally aligned with the position where impact pin 11 contacts crank 10 during its descent, meaning position sensor 3, impact pin 11, and the contact point of crank 10 are on the same plane. Impact pin 11 is threaded onto cylinder hammer 8, allowing impact pin 11 to strike crank 10 during the downward movement of cylinder hammer 8. Electronic fuel system 12 is located inside piston 9 and fuel tank 14.

[0030] like Figure 3 , Figure 4As shown, the electronic fuel system 12 includes a fuel injector 20, a fuel injector assembly 21, a pipe connector 22, a connecting nut 23, a fuel injector inlet pipe 24, a one-way valve 25, a switching solenoid valve 26, a common rail pipe 27, a two-position three-way solenoid valve 28, a two-position three-way solenoid valve outlet pipe 29, a two-position three-way solenoid valve return pipe 30, a two-position three-way solenoid valve inlet pipe 31, and a fuel pump assembly 32, installed from top to bottom. The fuel injector assembly 21 adopts the traditional structure of existing guide rod type diesel piling hammers; its fuel injector 20 has a spray hole 33 at the top, the fuel injector assembly 21 is connected to the pipe connector 22 by threads, and the connecting nut 23 is fastened to the fuel injector assembly 21 by threads. The switching solenoid valve 26 can control the connection and disconnection of the common rail outlet 34 and the fuel injector inlet pipe 24, and the switching solenoid valve 26 is a two-position two-way solenoid valve. The one-way valve 25 has a certain opening pressure, which can effectively prevent the fuel with lower pressure in the fuel line from flowing out of the nozzle 33 after the injection is completed. The fuel pump assembly 32 also adopts the traditional structure of the existing guide rod type diesel pile hammer; the fuel outlet of the fuel pump assembly 32 is connected to the pressure port P of the two-position three-way solenoid valve 28 through the fuel inlet pipe 31 of the two-position three-way solenoid valve. The working port A of the two-position three-way solenoid valve 28 is connected to the common rail 27 through the fuel outlet pipe 29 of the two-position three-way solenoid valve and the common rail inlet port 35 in sequence. The common rail outlet 34 on the common rail 27 is connected to the fuel injector inlet pipe 24 of the injector assembly 21 through the switching solenoid valve 26 and the one-way valve 25 in sequence. The working port A of the two-position three-way solenoid valve 28 is connected to the oil tank 14 via the common rail return pipe 39 and the common rail return solenoid valve 38. The common rail return solenoid valve 38 is a two-position two-way solenoid valve. The working port A of the two-position three-way solenoid valve 28 is connected to a pressure sensor 36 via the common rail 27. The pressure sensor 36 is a piezoresistive pressure sensor, but it could also be a piezoelectric pressure sensor or other corresponding pressure sensor. A pressure relief valve 37 is also installed on the common rail 27 connected to the working port A of the two-position three-way solenoid valve 28. This pressure relief valve 37 is a commonly used overflow valve. The return port T of the two-position three-way solenoid valve 28 is connected to the oil tank 14 via the two-position three-way solenoid valve return pipe 30. The electronic control unit 15 is electrically connected to the two-position three-way solenoid valve 28, the switching solenoid valve 26, the common rail return solenoid valve 38, and the pressure sensor 36. The electronic control unit 15 is a commonly used electronic control unit.

[0031] The pressure sensor 36 on the common rail 27 can transmit pressure signals to the electronic control unit 15. The pressure relief valve 37 on the common rail 27 is a mechanical relief valve. It will automatically open when the pressure in the common rail 27 is higher than a certain value, which can prevent the oil pressure in the common rail 27 from being too high and causing danger. The common rail return oil solenoid valve 38 can connect the common rail return oil pipe 39 to the oil tank when the rail pressure is higher than the set pressure, thereby reducing the rail pressure.

[0032] Figure 5The fuel pump assembly 32 shown includes a tappet 40, a plunger return spring seat 41, a plunger 42, a plunger return spring 43, a delivery valve 44, a delivery valve return spring 45, a delivery valve return spring seat 46, and a delivery valve bolt 47, which are installed from top to bottom. A plunger cavity 48 is formed between the plunger 42 and the delivery valve 44. A fuel pump inlet 49 and a filter element 50 are provided on both sides of the plunger cavity. The delivery valve 44 can form a conical seal with the fuel pump body 55. The delivery valve return spring seat 46 has a delivery valve outlet passage 51 inside, which is normally connected to the delivery valve cavity 52. ​​The delivery valve bolt 47 has a fuel pump outlet passage 53 inside, which is normally connected to the fuel inlet pipe of a two-position three-way solenoid valve through a flat connector 54.

[0033] The specific working process of the diesel pile driver with precise electronic fuel injection according to the present invention is as follows:

[0034] Before starting the pile driver, the landing gear 5 is lowered along the guide rod 4, and the hammer hook 17 below the landing gear 5 hooks the cylinder hammer 8. Then, a winch is used to lift the landing gear 5 and the cylinder hammer 8 through the pulley 7. When the pile driver starts, an external force triggers the release rod 18 on the landing gear 5, causing the hammer hook 17 of the landing gear 5 to separate from the cylinder hammer 8. The cylinder hammer 8 falls freely along the guide rod 4, and then the cylinder hammer 8 covers the piston 9, forming a sealed combustion chamber. The air temperature and pressure in the combustion chamber rise as the cylinder hammer 8 falls and is compressed. The cylinder hammer 8 continues to fall, and the impact pin 11 collides with the crank 10. The crank 10 rotates around the eccentric shaft 19 at a certain angle, compressing the tappet 40 and then the plunger 42 to supply oil. When the inlet pipe 31 of the two-position three-way solenoid valve is connected to the outlet pipe 29 of the two-position three-way solenoid valve, the high-pressure diesel fuel from the fuel pump assembly 32 flows into the common rail 27. When the inlet pipe 31 of the two-position three-way solenoid valve is connected to the return pipe 30 of the two-position three-way solenoid valve, the high-pressure diesel fuel from the fuel pump assembly 32 flows into the fuel tank 14. The fuel supply process of the fuel pump assembly 32 does not directly affect the fuel injection process. Only when the switching solenoid valve 26 receives an electrical signal from the electronic control unit 15 and opens, will the high-pressure diesel fuel be injected into the combustion chamber through the injection hole 33. At this time, the fuel injection process will begin. When the temperature in the combustion chamber is higher than the ignition point of diesel fuel, the diesel fuel injected into the combustion chamber will be ignited, and the combustion will release a large amount of heat, causing the pressure and temperature in the combustion chamber to rise sharply. The huge impact force causes the cylinder hammer 8 to bounce up, and at the same time pushes the piston 9 to drive the pile cap 13 downward to perform pile driving. During the process of the cylinder hammer 8 bouncing up, due to the weight of the cylinder hammer 8 and the friction, the cylinder hammer 8 will stop at a highest point, and then fall again to start the next working cycle. When the pile driver needs to stop working, simply close the solenoid valve 26 to stop the oil injection. This way, no fuel will participate in combustion to do work, and the height at which the cylinder hammer 8 is bounced will be greatly reduced. Moreover, as air leaks from the piston rings in the combustion chamber and energy is lost due to friction, the height at which the cylinder hammer 8 is bounced will become lower and lower until it eventually stops moving.

[0035] The diesel pile driver of this invention, with its precise electronic fuel injection, can detect the motion characteristics of the cylinder hammer 8 through position sensors 2 and 3, and transmit signals to the electronic control unit 15, thereby determining whether the cylinder hammer 8 is in the rising or falling process and the working condition of the pile driver. The electronic control unit 15 can achieve precise and flexible control of the circulating fuel injection quantity, injection pressure, and injection timing by controlling the opening and closing of the two-position three-way solenoid valve 28, the common rail return solenoid valve 38, and the switching solenoid valve 26.

[0036] The specific working principle of the electronic fuel system 12 is as follows: Before the pile driver starts, the plunger return spring seat 41, under the action of the plunger return spring 43, drives the plunger 42 to move upward and press against the lower end of the tappet 40. At this time, the plunger 42 is at the top dead center position. The diesel fuel in the fuel tank 14 flows into the plunger chamber 48 through the fuel pump inlet 49 after being filtered by the filter element 50. At this time, the oil pressure in the plunger chamber 48 is relatively small. The delivery valve 44, under the action of the delivery valve return spring 45, overcomes the oil pressure and moves upward, forming a conical seal with the fuel pump body 55. At this time, no diesel fuel flows out from the fuel pump assembly. After the pile driver starts, the cylinder hammer 8 falls freely and first seals with the piston 9 to form a combustion chamber. The position sensor 12 detects the displacement signal of the cylinder hammer 8 at this time. Then the cylinder hammer continues to fall, and the impact pin 11 installed on the cylinder hammer 8 collides with the crank 10. The position sensor 23 detects the displacement signal of the cylinder hammer 8 at this time. The impact pin 11 pushes the crank 10 to rotate around the eccentric shaft 19, overcoming the upward spring force of the plunger return spring 43, and pressing down the tappet 40, plunger 42, and plunger return spring seat 41. During the downward movement of the plunger 42, the diesel fuel in the fuel tank 14 is first disconnected and enters the plunger cavity 48 through the oil pump inlet 49, sealing the plunger cavity 48. Then, the plunger 42 continues to move downward to compress the diesel fuel in the plunger cavity 48, and the diesel fuel in the plunger cavity 48 begins to build up pressure until the hydraulic pressure on the upper surface of the delivery valve 44 is greater than the upward spring force of the delivery valve return spring 45. The delivery valve 44 opens, the oil pump 32 starts to supply oil, and the high-pressure diesel fuel in the plunger cavity 48 flows through the delivery valve 44 into the delivery valve cavity 52, and enters the two-position three-way valve inlet pipe 31 through the delivery valve outlet passage 51 and the oil pump outlet passage 53. After the diesel fuel flows out of the plunger chamber 48, the pressure inside the plunger chamber 48 will drop rapidly until the hydraulic pressure on the upper surface of the delivery valve 44 is less than the upward spring force of the delivery valve return spring 45. The delivery valve 44 will then move upward and form a conical seal with the oil pump body 55 again, ending the fuel supply. The impact pin 11 will also move upward along with the cylinder hammer 8, no longer pressing on the crank 10. At this time, the plunger return spring 43 will reset, lifting the plunger return spring seat 41, the plunger 42, and the tappet 40. The plunger 40 will then be at the top dead center position again, waiting for the next fuel supply.

[0037] The electronic control unit 15 determines whether the hammer cylinder 8 is in an upward or downward state, and the speed at which the hammer cylinder 8 is lifted, based on the order and time interval of receiving signals from position sensors 2 and 3, thereby determining the operating condition of the pile driver. If the signal from position sensor 2 is received first, the hammer cylinder 8 is in a downward state, and the electronic control unit 15 uses the moment of receiving this signal as the compression start point and the moment of receiving the signal from position sensor 3 as the oil supply start point. If the signal from position sensor 3 is received first, the hammer cylinder 8 is in an upward state, and the electronic control unit 15 determines the operating condition of the pile driver based on the time interval between receiving the signal from position sensor 2 again. The electronic control unit 15 can execute different oil injection strategies according to different operating conditions, including injection pressure, injection timing, and injection duration.

[0038] The injection pressure is adjusted by the electronic control unit 15 by comparing the actual rail pressure detected by the pressure sensor 36 of the common rail 27 with the theoretical rail pressure required for the current operating conditions, and by controlling the state of the valve port of the two-position three-way solenoid valve 28 and the opening and closing of the common rail return solenoid valve 38. When the actual rail pressure is higher than the theoretical rail pressure, the common rail return solenoid valve 38 opens, and the oil inlet pipe 31 and the oil return pipe 30 of the two-position three-way solenoid valve are connected, and the diesel fuel in the common rail 27 flows back to the fuel tank 14 until the actual rail pressure equals the theoretical rail pressure, and then the common rail return solenoid valve 38 closes. When the actual rail pressure is lower than the theoretical rail pressure, the common rail return solenoid valve 38 closes, and the two-position three-way solenoid valve 28 switches to connect the two-position three-way solenoid valve inlet pipe 31 and the two-position three-way solenoid valve outlet pipe 29. High-pressure oil from the fuel pump assembly 32 flows into the common rail 27 until the actual rail pressure equals the theoretical rail pressure. Then, the two-position three-way solenoid valve 28 switches to connect the two-position three-way solenoid valve inlet pipe 31 and the two-position three-way solenoid valve return pipe 30, and high-pressure diesel stops entering the common rail 27.

[0039] When the pile driver is in the downward direction, the electronic control unit 15 starts timing from receiving the signal from the non-contact displacement sensor 2. The injection timing is defined as the moment when the electronic control unit 15 sends a signal to open the solenoid valve 26. Subsequently, fuel is injected into the combustion chamber from the injection port 33, and the pile driver begins operation. The injection end time is defined as the moment when the electronic control unit 15 sends a signal to close the solenoid valve 26. The time interval between the injection timing and the injection end time is the injection duration. In other words, the electronic control unit 15 can control the injection timing and injection duration by controlling the opening and closing times of the solenoid valve 26 based on the compression start point.

[0040] Through calibration, the corresponding cyclic injection quantity under different injection pressures, injection timings, and injection durations can be obtained, and a MAP diagram of injection pressure-injection timing-injection duration-cyclic injection quantity can be plotted. The electronic control unit 15 can accurately control the cyclic injection quantity according to the calibrated MAP diagram.

[0041] The crank 10 is mounted on the eccentric shaft 19. In traditional guide rod type diesel hammer pile drivers, when adjusting the fuel injection quantity, workers need to manually adjust the positional relationship between the impact pin 11 and the crank 10, thereby adjusting the displacement of the tappet 40 and plunger 42 during the impact process, thus adjusting the fuel supply timing, fuel supply quantity, and fuel supply pressure to achieve fuel injection quantity regulation. As can be seen from the above working principle, the fuel supply process of traditional diesel hammer pile drivers directly affects the fuel injection process and requires manual adjustment. However, the diesel pile driver of this invention can not only achieve independent control of the fuel injection process through a two-position three-way solenoid valve 28, a common rail pipe 27, and a switching solenoid valve 26, decoupling the injection process from the fuel supply process, but also use an electronic control unit 15 to replace manual regulation. This not only increases the injection pressure but also allows for flexible changes in injection timing and cyclic fuel injection quantity, improving combustion, reducing emissions of pollutants such as soot and NOx, and increasing the maximum cylinder explosion pressure, thus improving pile driving efficiency. At the same time, a MAP diagram can be obtained based on the calibration, enabling the pile driver to adapt to different operating conditions and making the pile driver more intelligent.

[0042] The above embodiments illustrate a preferred embodiment of the present invention, but the present invention is not limited thereto. Some modifications can be made without departing from the basic principles of the present invention, such as replacing the fuel injector 20, fuel injector assembly 21 and nozzle portion 33 in the electronic fuel system with an electronic fuel injector, which also falls within the protection scope of the present invention.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A precision electronically controlled fuel injection diesel pile driver, comprising two parallel guide rods (4), a top crossbeam (6) fixedly installed at the upper end of the guide rods (4), a piston (9) fixedly connected to the lower end of the guide rods (4), and a cylinder hammer (8) slidably supported on the guide rods (4), characterized in that: The piston (9) is equipped with an electronic fuel system (12) and an electronic control unit (15). Position sensor 1 (2) and position sensor 2 (3) are located on the outer side of the piston (9). The electronic fuel system (12) includes a fuel pump assembly (32), a fuel injector assembly (21), and a two-position three-way solenoid valve (28). The outlet of the fuel pump assembly (32) is connected to the pressure port P of the two-position three-way solenoid valve (28). The working port A of the two-position three-way solenoid valve (28) is connected to the inlet of the fuel injector assembly (21) via a switching solenoid valve (26). The working port A of the two-position three-way solenoid valve (28) is also connected to the fuel tank (14) via a common rail return solenoid valve (38). A pressure sensor (36) is also connected to the working port A of the two-position three-way solenoid valve (28). The return port T of the two-position three-way solenoid valve (28) is connected to the fuel tank (14). The electronic control unit (15)... The piston (9) is electrically connected to a two-position three-way solenoid valve (28), a switching solenoid valve (26), a common rail return solenoid valve (38), and a pressure sensor (36), respectively. The piston (9) includes a piston seat and a piston body that are integrated together. The oil tank (14) is fixed on the piston seat. A piston ring is fitted on the cylindrical surface of the piston body. The position sensor (2) is on the same plane as the uppermost piston ring of the piston body of the piston (9). The fuel pump assembly (32) includes a plunger (42) and a tappet (40) that are movably supported on the pump body (55). One end of the crank (10) hinged on the piston (9) is in contact with the tappet (40). The other end of the crank (10) is corresponding to the impact pin (11), which is fixedly installed on the cylinder hammer (8). The position sensor (3) is on the same plane as the contact point of the impact pin (11) and the crank (10).

2. The diesel pile driver with precision electronic fuel injection according to claim 1, characterized in that: The working port A of the two-position three-way solenoid valve (28) is connected to the oil tank (14) via the pressure relief valve (37), which is an overflow valve.

3. The diesel pile driver with precision electronic fuel injection according to claim 1, characterized in that: The working port A of the two-position three-way solenoid valve (28) is connected to the inlet of the fuel injector assembly (21) via the switching solenoid valve (26) and the check valve (25).

4. The diesel pile driver with precision electronic fuel injection according to claim 1, 2 or 3, characterized in that: The switching solenoid valve (26) and the common rail return solenoid valve (38) are two-position two-way solenoid valves, and the pressure sensor (36) is a piezoresistive pressure sensor or a piezoelectric pressure sensor.

5. The diesel pile driver with precision electronic fuel injection according to claim 1, characterized in that: The position sensor one (2) and position sensor two (3) are fixedly installed on the sensor bracket (1), which is fixedly connected to the top crossbeam (6) and / or the piston (9).

6. The diesel pile driver with precision electronic fuel injection according to claim 1, characterized in that: The fuel pump assembly (32) has its outlet port connected to the pressure port P of the two-position three-way solenoid valve (28) via the inlet pipe (31) of the two-position three-way solenoid valve. The working port A of the two-position three-way solenoid valve (28) is connected to the common rail inlet port (35) via the outlet pipe (29) of the two-position three-way solenoid valve. The return port of the two-position three-way solenoid valve (28) is connected to the fuel tank (14) via the return pipe (30) of the two-position three-way solenoid valve.

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