An electronically controlled single fuel injection pump for heavy oil

Abstract

The present invention relates to a heavy oil electronically controlled unit pump, which comprises a plunger, a plunger sleeve, a bypass valve and a bypass valve sleeve. A plunger chamber is formed between the plunger and the plunger sleeve. A bypass valve sleeve chamber is formed between the bypass valve and the bypass valve sleeve. The bypass valve sleeve is installed inside the plunger sleeve. The bypass valve sleeve chamber communicates with the plunger chamber. The plunger sleeve is provided with independent fuel flow channels and cooling oil flow channels. The fuel flow channels and the cooling oil flow channels respectively have a fuel chamber and a cooling oil chamber. The positions of the fuel chamber and the cooling oil chamber respectively correspond to the tail position and the head position of the bypass valve sleeve. A leakage oil return groove is arranged at the matching position of the bypass valve sleeve and the bypass valve. The leakage oil return groove is located between the fuel chamber and the cooling oil chamber and communicates with the outside. The present invention enables the solenoid valve spool not to contact the heavy oil being burned, prevents the electromagnet from shifting, and ensures the normal operation of the fuel injection pump.

Description

Technical Field

[0001] The present invention relates to the technical field of diesel engines, and particularly to a heavy oil electronically controlled unit pump. Background Art

[0002] The electronically controlled unit pump can adjust the injection timing and pulse width according to the operating conditions of the diesel engine; comprehensively optimize the injection strategy to make the combustion of the diesel engine reach the best condition under various operating conditions, greatly reduce the fuel consumption rate, and reduce the generation of exhaust pollutants while reducing fuel consumption. Traditional electronically controlled unit pumps all burn light oil, resulting in higher costs.

[0003] In order to balance the pressure at the head and tail of the bypass valve, the electronically controlled unit pump of the prior art is provided with oil passages at positions corresponding to the head and bottom of the bypass valve in the plunger sleeve, and the two oil passages are connected. When burning light oil, heating is not required, so the structure of the electronically controlled unit pump of the prior art will not affect its use. However, when burning heavy oil to save costs, since the viscosity of heavy oil is relatively large at normal temperature, the heavy oil needs to be heated. Since an electromagnetic valve is generally provided at the head of the bypass valve, and the electromagnetic valve is used to control the opening or closing of the bypass valve, if the solenoid valve spool directly contacts the burning heavy oil, when the relatively high-temperature heavy oil contacts the electromagnetic valve, the electromagnetic valve will be heated and expanded, causing the electromagnet to shift, resulting in the failure of the electromagnetic valve to work properly and causing the fuel injection pump to fail. Summary of the Invention

[0004] The purpose of the present invention is to provide a heavy oil electronically controlled unit pump to solve the problem that the structure of the electronically controlled unit pump of the prior art is likely to cause the electromagnetic valve to fail to work properly and cause the fuel injection pump to fail when using heavy oil.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A heavy oil electronically controlled unit pump includes a plunger, a plunger sleeve, a bypass valve and a bypass valve sleeve. The plunger and the plunger sleeve form a plunger chamber, the bypass valve and the bypass valve sleeve form a bypass valve sleeve chamber. The bypass valve sleeve is installed inside the plunger sleeve, and the bypass valve sleeve chamber is connected to the plunger chamber. The plunger sleeve has independent fuel flow passages and cooling oil flow passages. The fuel flow passage and the cooling oil flow passage respectively have a fuel chamber and a cooling oil chamber. The positions of the fuel chamber and the cooling oil chamber respectively correspond to the tail position and the head position of the bypass valve sleeve. A leakage return oil groove is provided at the position where the bypass valve sleeve cooperates with the bypass valve. The leakage return oil groove is located between the fuel chamber and the cooling oil chamber and is communicated with the outside.

[0007] According to the above technical means, since the fuel flow channel and the cooling oil flow channel are independent of each other, there will be no problem of a large amount of fuel (here it is heavy fuel oil, hereinafter all referred to as fuel) flowing into the cooling oil flow channel. The positions of the fuel chamber and the cooling oil chamber correspond to the tail position and the head position of the bypass valve sleeve respectively, which can balance the oil pressures at both ends of the bypass valve sleeve. Moreover, since there is a leakage oil return groove formed in the gap between the bypass valve sleeve and the plunger sleeve, and the leakage oil return groove is located between the fuel chamber and the cooling oil chamber and is connected to the outside, when a small amount of cooling oil and fuel flow into the gap between the bypass valve sleeve and the plunger sleeve, they will be aggregated in the leakage oil return groove. At this time, under the action of the oil pressure, the pressure in the leakage oil return groove is greater than the external pressure, and this part of the mixed oil can flow to the outside, thus fundamentally avoiding the fuel from flowing into the cooling oil chamber and contacting the electromagnetic valve arranged at the head of the bypass valve sleeve.

[0008] Further, when the pressure in the fuel chamber reaches the pressure threshold, the fuel chamber is connected to the outside; otherwise, the fuel chamber is not connected to the outside.

[0009] According to the above technical means, rapid pressure relief of the fuel chamber can be achieved.

[0010] Further, when the plunger starts to move upward, the bypass valve opens, and the fuel chamber is connected to the bypass valve sleeve chamber; when the time for the plunger to move upward increases to the first moment, the bypass valve closes, and the fuel chamber is not connected to the bypass valve sleeve chamber; when the time for the plunger to move upward increases to the second moment, the bypass valve opens, so that the pressure in the fuel chamber increases to at least the pressure threshold.

[0011] According to the above technical means, while achieving pressure relief of the fuel chamber, pressure relief of the bypass valve sleeve chamber is also achieved.

[0012] Further, an armature is fixedly installed at the bottom of the bypass valve, a first electromagnetic valve is installed on the plunger sleeve, and the heavy oil unit pump is also provided with a bypass valve spring. The top of the bypass valve spring is connected to the bottom of the bypass valve, and the other end is fixed. When the first electromagnetic valve is energized, the magnetic force of the first electromagnetic valve attracts the armature and moves downward against the elastic force of the bypass valve spring, so that the bypass valve closes; when the first electromagnetic valve is de-energized, the bypass valve resets under the action of the elastic force of the bypass valve spring, and the bypass valve opens.

[0013] Further, the first electromagnetic valve is installed on the plunger sleeve through a backing plate. The backing plate is provided with a through hole, the armature is located inside the through hole, and the through hole is connected to the cooling oil chamber, so that the cooling oil in the cooling oil chamber can flow to the armature.

[0014] Further, the heavy oil single pump is provided with a pressure control valve component, the pressure control valve component includes a valve housing and a valve core, the valve core is located inside the valve housing, the valve housing is provided with a cooling oil outlet, and an oil return groove is arranged inside the valve housing. The oil return groove is located between the cooling oil outlet and the cooling oil cavity. When the valve core moves upward, the part of the valve core entering the oil return groove gradually increases, so that the part where the cooling oil outlet communicates with the cooling oil cavity gradually decreases until it is not connected. When the valve core moves downward, the part of the valve core entering the oil return groove gradually decreases, so that the part where the cooling oil outlet communicates with the cooling oil cavity gradually increases.

[0015] According to the above technical means, by adjusting the upward or downward stroke of the valve core, the volume of the valve core entering the oil return groove can be adjusted, and then the purpose of controlling the pressure of the cooling oil cavity can be achieved.

[0016] Further, when the first solenoid valve is de-energized, the valve core moves upward and closes the communication hole, so that the cooling oil outlet and the cooling oil cavity are not connected.

[0017] Further, the bottom of the valve core is connected to the valve stem of the second solenoid valve, the top of the valve core is connected to the bottom end of the return spring, the top end of the return spring is fixed, and when the first solenoid valve is de-energized, the second solenoid valve is opened.

[0018] Further, a reflux valve is arranged between the fuel cavity and the external environment. When the pressure threshold is reached, the reflux valve opens, otherwise, the reflux valve closes.

[0019] Further, the plunger sleeve is provided with a cooling oil inlet and a fuel inlet. The cooling oil inlet and the fuel inlet are respectively communicated with the cooling oil cavity and the fuel cavity, and both the cooling oil inlet and the fuel inlet are communicated with the external environment.

[0020] Advantages of the present invention:

[0021] The present invention completely separates the cooling oil passage from the fuel oil passage, avoids the mixing of heavy oil and cooling oil, makes the solenoid valve core unable to contact the burned heavy oil, prevents the electromagnet from shifting, ensures the normal operation of the fuel injection pump, and at the same time, the formed cooling oil passage can use lubricating oil or light fuel to cool the solenoid valve, improving the reliability of the solenoid valve;

[0022] The present invention is provided with a pressure control valve component and a return valve, and the pressure of the cooling oil cavity can be adjusted by adjusting the opening degree of the stroke of the valve core, assisting the quick pressure relief of the bypass valve sleeve cavity, the plunger cavity and the fuel cavity. Description of the drawings

[0023] Figure 1 It is a sectional view of a heavy oil electronically controlled single pump;

[0024] Figure 2 It is an external view of a heavy oil electronically controlled single pump;

[0025] Figure 3 It is a sectional view of the plunger couple;

[0026] Figure 4 It is a sectional view of the pressure control valve component and the solenoid valve component;

[0027] Figure 5 It is a partial enlarged view of the leakage oil return groove;

[0028] Figure 6 It is a partial enlarged view of the communication hole.

[0029] Among them, 1 - dual control valve component, 2 - fuel injection pump body, 3 - upper spring disc, 4 - plunger spring, 5 - guide piston assembly, 6 - pipe joint screw, 7 - throttle plug, 8 - fuel oil return port, 9 - cooling oil return port, 10 - high-pressure fuel outlet, 11 - cooling oil and heavy oil mixed return port, 12 - cooling oil inlet, 13 - fuel inlet, 14 - lubricating oil inlet, 15 - plunger sleeve, 16 - plunger, 17 - plunger cavity, 18 - bypass valve sleeve cavity, 19 - oil return screw, 20 - pressure regulating gasket, 21 - pressure regulating spring, 22 - oil return valve, 23 - baffle, 24 - fuel oil return passage, 25 - bypass valve sleeve, 26 - bypass valve, 27 - bypass valve spring, 28 - backing plate, 29 - spring disc, 30 - bypass valve screw, 31 - armature, 32 - first solenoid valve, 33 - cooling oil cavity, 34 - leakage oil return groove, 35 - fuel oil inlet passage, 36 - cooling oil return hole, 37 - second solenoid valve, 38 - valve core, 39 - valve sleeve, 40 - valve housing, 41 - return spring, 42 - spring disc, 43 - screw rod, 44 - nut, 45 - fuel oil cavity; 46 - oil return groove; 47 - communication hole. Specific embodiments

[0030] The following will illustrate the implementation manner of the technical solution of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, rather than for limiting the protection scope of the present invention.

[0031] It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the drawings, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0032] This embodiment proposes a heavy oil electronically controlled unit pump, as Figures 1-5 shown, which includes a dual-control valve component 1, a fuel injection pump body 2, an upper spring plate 3, a plunger spring 4, a guide piston assembly 5, a pipe joint screw 6, a throttle plug 7, a fuel oil return port 8, a cooling oil return port 9, a high-pressure fuel outlet 10, a cooling oil heavy oil mixed return port 11, a cooling oil inlet 12, a fuel inlet 13, a lubricating oil inlet 14, a plunger sleeve 15, a plunger 16, a plunger chamber 17, a bypass valve sleeve chamber 18, a return screw 19, a pressure regulating gasket 20, a pressure regulating spring 21, a return valve 22, a baffle 23, a fuel oil return passage 24, a bypass valve sleeve 25, a bypass valve 26, a bypass valve spring 27, a backing plate 28, a spring plate 29, a bypass valve screw 30, an armature 31, a first solenoid valve 32, a cooling oil chamber 33, a leakage return oil groove 34, a fuel oil inlet passage 35, a cooling oil return hole 36, a second solenoid valve 37, a valve core 38, a valve sleeve 39, a valve housing 40, a return spring 41, a spring plate 42, a screw rod 43, a nut 44, a fuel chamber 45, a return oil groove 46 and a communication hole 47.

[0033] The dual-control valve component 1 includes a plunger pair, a pressure control valve component and a solenoid valve component. The plunger pair is a precision pair composed of a plunger sleeve 15 and a plunger 16. The space between the plunger 16 and the plunger sleeve 15 forms a plunger chamber 17. The pressure control valve component includes a second solenoid valve 37, a valve core 38, a valve sleeve 39, a valve housing 40, a return spring 41, a spring plate 42, a screw rod 43 and a nut 44. The valve core 38 and the valve sleeve 39 are in paired fit. One end of the valve core 38 is connected to the valve rod in the second solenoid valve 37, and one end is equipped with a return spring 41 and is installed in the valve housing 40 together with the valve sleeve 39. The spring plate 42 is pressed by the return spring 41 on the screw rod 43. The screw rod 43 is fixed to the valve housing 46 through the nut 44. The second solenoid valve 37 is fixed to the valve housing 40 by means of a threaded connection. The pressure control valve component is connected to the plunger pair by two screws.

[0034] The solenoid valve component includes an oil return screw 19, a pressure regulating gasket 20, a pressure regulating spring 21, an oil return valve 22, a baffle plate 23, a bypass valve sleeve 25, a bypass valve 26, a bypass valve spring 27, a backing plate 28, a spring disc 29, a bypass valve screw 30, an armature 31, and a first solenoid valve 32. The bypass valve sleeve 25 and the bypass valve 26 are a matched pair of parts with a tapered surface seal, and the volume between them forms a bypass valve sleeve cavity 18. The bypass valve sleeve 25 is press-fitted into a specified position in the plunger sleeve 15 with an interference fit. The bottom of the bypass valve 26 is connected to the armature 31 through the bypass valve screw 30 to form a moving valve part. The first solenoid valve 32 is located below the armature 31. A backing plate 28 is installed on the plunger sleeve 15, and the first solenoid valve 32 is installed at the bottom of the backing plate 28. A through hole is provided on the backing plate 28, and the armature 31 is located inside the through hole. The upper and lower ends of the through hole are blocked by the spring disc 29 and the first solenoid valve 32 respectively. The two ends of the bypass valve spring 27 abut against the bypass valve 26 and the spring disc 29 respectively. When the first solenoid valve 32 is energized, an attractive force can be generated to attract the armature 31 to move downward and overcome the elastic force of the bypass valve spring 27, thereby closing the bypass valve 26. When the first solenoid valve is de-energized, the bypass valve spring 27 resets, causing the bypass valve 26 to move upward until it abuts against the baffle plate 23, realizing the opening of the bypass valve 26.

[0035] The oil return screw 19, the pressure regulating gasket 20, the pressure regulating spring 21, the oil return valve 22, and the baffle plate 23 form an oil return valve assembly, which is installed on the plunger sleeve 15 through screws. Multiple self-lubricating grooves are provided on the oil return valve 22 to prevent jamming when the oil return valve 22 is switched.

[0036] In this embodiment, the heavy oil electronic unit pump is installed on the lifting mechanism of the diesel engine. When it works, the lifting mechanism reciprocates up and down to drive the guide piston assembly 5 and the plunger 16 to reciprocate at high speed. Fuel (heavy fuel oil, hereinafter referred to as fuel) enters the fuel injection pump body 2 through the fuel inlet 13, then reaches the fuel chamber 45 through the fuel inlet passage 35 on the plunger sleeve 21, communicates with the fuel return passage 30, and reaches the fuel return port 8. Therefore, the fuel inlet 13, the fuel inlet passage 35, the fuel chamber 45, the fuel return passage 30, and the fuel return port 8 form a fuel flow path, and the fuel flow path is arranged on the plunger sleeve 15. The position of the fuel chamber 45 in this embodiment corresponds to the position of the tail of the bypass valve sleeve 25.

[0037] A cooling flow passage is provided on the plunger sleeve 15. The cooling flow passage includes a cooling oil inlet 12, a cooling oil chamber 39, a cooling oil return hole 36, and a cooling oil return port 9. During the downward movement and oil filling process of the plunger 16, the first solenoid valve 32 and the second solenoid valve 37 are de-energized, and the valve core 38 is in an open state. The cooling oil enters the cooling oil chamber 39 through the cooling oil inlet 12 on the plunger sleeve 15, then enters the oil return groove 46 in the pressure control valve component through the cooling oil return hole 36, flows through the communication hole 47 to the cooling oil return port 9, and finally flows out through the cooling oil return port 9, taking away the heat of the solenoid valve chamber. The position of the cooling oil chamber 39 corresponds to the position of the head of the bypass valve sleeve 25. As Figure 6 shown, the communication hole 47 is provided at the valve port of the valve sleeve 39 and is located inside the oil return groove 46. The oil return groove 46 is the position where the cooling oil converges. When the valve core 38 moves upward, the valve core 38 gradually enters the inside of the valve sleeve 39, causing the cross-sectional area of the communication hole 47 to gradually decrease, and the part where the cooling oil return port 9 and the cooling oil return hole 36 are connected to gradually decrease until the valve core 38 completely blocks the communication hole 47, thereby preventing the cooling oil in the cooling oil chamber 39 from flowing out and causing the pressure in the cooling oil chamber 39 to increase; conversely, when the valve core 38 moves downward, the part of the valve core 38 extending out of the valve sleeve 39 becomes larger, the cross-sectional area of the communication hole 47 gradually increases, and the flow rate of the cooling oil in the cooling oil chamber 39 flowing into the outside gradually increases.

[0038] Therefore, in this embodiment, the cooling flow passage and the fuel flow passage are independent of each other, and a leakage oil return groove 34 is provided on the mating surface of the bypass valve sleeve 25 and the bypass valve. The leakage oil return groove 34 communicates with the outside through the cooling oil and heavy oil mixed return port 11. The leakage oil return groove 34 is located between the cooling oil chamber 39 and the fuel chamber 45. When a small amount of the cooling oil in the cooling oil chamber 39 and the fuel in the fuel chamber 45 enter the volume between the bypass valve sleeve 25 and the bypass valve, this part of the mixed oil will be collected in the leakage oil return groove 34. Due to the oil pressure (formed by cooling oil, fuel, and lubricating oil), and the outside is at atmospheric pressure, under the action of the pressure, the mixed oil will be discharged from the leakage oil return groove 34 to the outside, thereby avoiding the mixing of fuel and cooling oil. Further, it can prevent fuel from flowing into the cooling oil chamber 39 through the gap between the bypass valve sleeve 25 and the plunger sleeve 15, causing the relatively high-temperature heavy oil to contact the first solenoid valve 32. The cooling oil can also be used as the lubricating oil for the bypass valve 26 to prevent the bypass valve 26 from getting stuck during movement.

[0039] In this embodiment, when the plunger 16 starts to move upward, the first solenoid valve 32 is de-energized, and the bypass valve 26 is in the open state under the action of the elastic force of the bypass valve spring 27. The fuel chamber 45 is communicated with the bypass valve sleeve chamber 18, and then with the plunger chamber 17 (the bypass valve sleeve chamber 18 is communicated with the plunger chamber 17). The fuel in the fuel chamber 45 fills into the plunger chamber 17, the pressure of the fuel chamber 45 decreases, and the oil return valve 28 is in the closed state at this time; when the plunger 16 moves upward to the first moment, the ECU gives a pulse signal to control the first solenoid valve 32 to be energized to generate electromagnetic suction, adsorbing the moving valve parts composed of the armature 31, the bypass valve screw 29, and the bypass valve 26. The bypass valve 26 closes, the fuel chamber 45 is separated from the bypass valve sleeve chamber 18, and the fuel in the plunger chamber 17 builds high pressure under the action of the continuously moving upward plunger 16 at high speed. The fuel reaches the high-pressure oil outlet 10 and enters the injector. When the pressure reaches the opening pressure of the injector, fuel supply can be carried out.

[0040] When the plunger 16 continues to move upward to the second moment, the pressure in the plunger chamber 17 continues to increase. The first solenoid valve 32 is de-energized, and the bypass valve 26 returns to its position under the action of the bypass valve spring 27. The bypass valve 27 opens, and the fuel chamber 45 is reconnected to the plunger chamber 17, resulting in the pressure of the fuel chamber 45 rising to the pressure threshold. Since the fuel chamber 45 is communicated with the oil return valve 22, the pressure threshold in this embodiment is the opening pressure of the oil return valve 22. Therefore, the oil return valve 22 opens (in this embodiment, the opening threshold of the oil return valve 22 can be adjusted by adjusting the position of the pressure regulating gasket 20 and the tightness of the pressure regulating spring 21), so that the fuel chamber 45 is communicated with the outside, and then the pressures in the bypass valve sleeve chamber 18 and the fuel chamber 45 are quickly unloaded. At the same time, the second solenoid valve 37 is energized, and the valve stem in the second solenoid valve 37 drives the valve core 46 to move upward, gradually closing the communication hole 47, so that the cooling oil cannot flow out from the cooling oil chamber 33. Then the pressure in the cooling oil chamber 33 increases, balancing the acting force of the increased pressure in the fuel chamber 45 during pressure relief on the bypass valve, and enabling the plunger chamber 17 to quickly relieve pressure. After the pressure relief is completed, the second solenoid valve 37 is de-energized, and the valve core 38 returns to its position under the elastic force of the return spring 41, and the cooling oil passage is reconnected.

[0041] The cooling oil outlet 9 is arranged on the valve housing 40. There is an oil return groove 46 in the valve housing 40. When the second solenoid valve 27 is energized, the valve stem inside it drives the valve core 38 to move upward, and the return spring 41 is compressed. The valve core 38 gradually closes the communication hole 47, and the cooling oil in the oil return groove 46 gradually cannot flow out, so that the part of the cooling oil outlet 9 communicated with the cooling oil chamber 33 gradually decreases until it is not communicated. When the second solenoid valve 27 is de-energized, the valve core 38 moves downward under the elastic force of the return spring 41, and the cross-sectional area of the communication hole 47 gradually becomes larger, so that the part of the cooling oil outlet 9 communicated with the cooling oil chamber 33 gradually increases. Thus, the pressure of the cooling oil chamber 33 can be regulated in the above way.

[0042] In this embodiment, when the first solenoid valve 32 is de-energized, the valve core 38 moves upward to close the communication hole 47, so that the cooling oil outlet 9 and the cooling oil chamber 33 are not in communication, thereby increasing the pressure in the cooling oil chamber 33.

[0043] In this embodiment, an oil passage hole is provided on the spring disc 29, and the cooling oil in the cooling oil chamber 33 can flow into the armature 31 through the oil passage hole. When this part of the cooling oil flows to the outside, the heat generated when the first solenoid valve 32 is energized can be taken away through the armature 31.

[0044] The above embodiments are only preferred embodiments given to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention.

Claims

1. A heavy oil electronically controlled unit pump, comprising a plunger (16), a plunger sleeve (15), a bypass valve (26) and a bypass valve sleeve (25). The plunger (16) and the plunger sleeve (15) form a plunger chamber (17), the bypass valve (26) and the bypass valve sleeve (25) form a bypass valve sleeve chamber (18), the bypass valve sleeve (25) is installed inside the plunger sleeve (15), and the bypass valve sleeve chamber (18) is communicated with the plunger chamber (17). It is characterized in that: The plunger sleeve (15) is provided with independent fuel flow channels and cooling oil flow channels. The fuel flow channels and the cooling oil flow channels are respectively provided with a fuel cavity (45) and a cooling oil cavity (33). The positions of the fuel cavity (45) and the cooling oil cavity (33) respectively correspond to the tail position and the head position of the bypass valve sleeve (25). A leakage return oil groove (34) is provided at the position where the bypass valve sleeve (25) cooperates with the bypass valve. The leakage return oil groove (34) is located between the fuel cavity (45) and the cooling oil cavity (33), and the leakage return oil groove (34) communicates with the outside; An armature (31) is fixedly installed at the bottom of the bypass valve (26). A first solenoid valve (32) is installed on the plunger sleeve (15). The heavy oil electronically controlled unit pump is further provided with a bypass valve spring (27). The top end of the bypass valve spring (27) is connected to the bottom of the bypass valve (26), and the other end is fixed. When the first solenoid valve (32) is energized, the magnetic force of the first solenoid valve (32) attracts the armature (31) and moves downward against the elastic force of the bypass valve spring (27), so that the bypass valve (26) is closed. When the first solenoid valve (32) is de-energized, the bypass valve (26) resets under the action of the elastic force of the bypass valve spring (27), and the bypass valve (26) opens; The heavy oil electronically controlled unit pump is provided with a pressure control valve component. The pressure control valve component includes a valve housing (40), a valve core (38) and a valve sleeve (39). The valve core (38) is located inside the valve housing (40). The valve housing (40) is provided with a cooling oil outlet. The valve sleeve (39) is provided with a communication hole. The communication hole communicates with the cooling oil outlet and the cooling oil cavity (33). When the valve core (38) moves upward, the cross-sectional area of the communication hole gradually decreases until it is not connected. When the valve core (38) moves downward, the cross-sectional area of the communication hole gradually increases.

2. The heavy oil electronically controlled unit pump according to claim 1, characterized in that: When the pressure in the fuel cavity (45) reaches the pressure threshold, the fuel cavity (45) communicates with the outside. Otherwise, the fuel cavity (45) does not communicate with the outside.

3. The heavy oil electronically controlled unit pump according to claim 2, characterized in that: When the plunger (16) starts to move upward, the bypass valve (26) opens, and the fuel cavity (45) communicates with the bypass valve sleeve cavity (18); when the time when the plunger (16) moves upward increases to the first time, the bypass valve (26) closes, and the fuel cavity (45) does not communicate with the bypass valve sleeve cavity (18); when the time when the plunger (16) moves upward increases to the second time, the bypass valve (26) opens, so that the pressure in the fuel cavity (45) increases to at least the pressure threshold.

4. The heavy oil electronically controlled unit pump according to claim 3, characterized in that: The first solenoid valve (32) is installed on the plunger sleeve (15) through a backing plate. The backing plate is provided with a through hole. The armature (31) is located inside the through hole. The through hole communicates with the cooling oil cavity (33), so that the cooling oil in the cooling oil cavity (33) can flow to the armature (31).

5. The heavy oil electronically controlled unit pump according to claim 4, characterized in that: When the first solenoid valve (32) is de-energized, the valve core (38) moves upward and closes the communication hole, so that the cooling oil outlet and the cooling oil cavity (33) are not connected.

6. The heavy oil electronically controlled unit pump according to claim 5, characterized in that: The bottom of the valve core (38) is connected to the valve stem of the second solenoid valve (37). The top of the valve core (38) is connected to the bottom end of the return spring (41), and the top end of the return spring (41) is fixed. When the first solenoid valve (32) is de-energized, the second solenoid valve (37) opens.

7. The heavy oil electronically controlled unit pump according to claim 2, characterized in that: A return valve is provided between the fuel chamber (45) and the external environment. When the pressure threshold is reached, the return valve opens; otherwise, the return valve closes.

8. The heavy oil electronically controlled unit pump according to claim 2, characterized in that: A cooling oil inlet (12) and a fuel inlet (13) are provided on the plunger sleeve (15). The cooling oil inlet (12) and the fuel inlet (13) are respectively communicated with a cooling oil chamber (33) and a fuel chamber (45), and both the cooling oil inlet (12) and the fuel inlet (13) are communicated with the external environment.

Images