A feed pump for low boiling point fuel

Abstract

The utility model belongs to the technical field of common rail fuel supply, and particularly relates to a supply pump for low boiling point fuel, comprising: an oil inlet metering valve, an oil inlet valve assembly, an oil outlet valve assembly, an oil supply drive assembly and a one-way oil return valve assembly; the oil inlet of the oil inlet metering valve is connected to the oil tank, the oil outlet of the oil inlet metering valve is connected to the oil inlet of the oil inlet valve assembly, the oil outlet of the oil inlet valve assembly is connected to the oil supply flow channel, one end of the oil supply flow channel is connected to the oil supply drive assembly, the other end of the oil supply flow channel is connected to the oil inlet of the oil outlet valve assembly, the oil inlet of the one-way oil return valve assembly is connected to the oil supply flow channel through the low-pressure chamber flow channel in the pump, the oil outlet of the one-way oil return valve assembly is connected to the oil return flow channel, and the oil return flow channel is connected to the oil tank. The utility model can make the fuel pressure in the low-pressure chamber in the pump always consistent with the oil return back pressure in the engine system, and at the same time can use the higher oil return back pressure in the engine oil return liquid circuit to realize the one-way seal in the one-way valve assembly to realize the normal shutdown of the engine.

Description

Technical Field

[0001] The utility model belongs to the technical field of common rail fuel supply, in particular to a supply pump for low boiling point fuel. Background Art

[0002] Currently, most high-pressure common rail pumps on the market are suitable for traditional liquid fuels such as diesel and gasoline. With the dual carbon goals in the transportation field and the need for national energy structure transformation, various new alternative fuels are gradually emerging.

[0003] New low-carbon fuels such as dimethyl ether and liquid ammonia have significant advantages in terms of clean emissions compared to traditional gasoline and diesel fuels, but the boiling point of the fuel is low, and a relatively high pressure must be maintained to ensure that the fuel exists in liquid form. The existing common rail system generally requires the return oil circuit of the oil pump to maintain a low return oil back pressure to prevent the return oil circuit from throttling and being unable to shut down. This structure is obviously not suitable for low-boiling-point fuels. Summary of the invention

[0004] The utility model provides a supply pump for low-boiling-point fuel, so as to solve the problem that the traditional common rail system in the background technology is not suitable for low-boiling-point fuel.

[0005] The technical solution of the utility model is as follows: a supply pump for low boiling point fuel, comprising: an oil inlet metering valve, an oil inlet valve assembly, an oil outlet valve assembly, an oil supply drive assembly and a one-way oil return valve assembly;

[0006] The oil inlet of the oil inlet metering valve is connected to the oil tank, the oil outlet of the oil inlet metering valve is connected to the oil inlet of the oil inlet valve assembly, the oil outlet of the oil inlet valve assembly is connected to the oil supply channel, one end of the oil supply channel is connected to the oil supply drive assembly, the other end of the oil supply channel is connected to the oil inlet of the oil outlet valve assembly, the oil inlet of the one-way oil return valve assembly is connected to the oil supply channel through the low-pressure chamber channel in the pump, the oil outlet of the one-way oil return valve assembly is connected to the oil return channel, and the oil return channel is connected to the oil tank.

[0007] Furthermore, the oil supply drive assembly comprises: a camshaft, a tappet body and a plunger pair, the camshaft is mounted on one end of the tappet body, and the other end of the tappet body is connected to the plunger pair.

[0008] Furthermore, the plunger couple includes: a plunger sleeve, a plunger, a plunger oil seal and a plunger cavity, one end of the plunger is connected to the tappet body, the plunger sleeve is sleeved on the plunger, the plunger oil seal is arranged at one end of the plunger sleeve close to the tappet body and is slidably connected to the plunger, the plunger cavity is arranged at one end of the plunger sleeve away from the tappet body, and the other end of the plunger is placed in the plunger cavity.

[0009] Furthermore, the one-way oil return valve assembly includes: an oil return valve seat, a sealing valve ball and a cover plate, the sealing valve ball is arranged in the oil return valve seat, the cover plate is fixedly connected to the sealing valve ball, the oil return valve seat is provided with an oil inlet hole at one end facing away from the cover plate, and the cover plate is provided with a circulation hole.

[0010] Furthermore, the oil inlet hole is communicated with the low-pressure chamber flow channel in the pump, the flow hole is communicated with the oil return channel of the oil return joint, and the oil return joint is communicated with the oil return flow channel.

[0011] Furthermore, a sealing cone surface is provided in the oil return valve seat, and the sealing valve ball contacts the sealing cone surface.

[0012] Furthermore, the oil inlet of the oil inlet metering valve is connected to the first filter, the oil pump and the second filter in sequence.

[0013] Furthermore, the oil return channel is connected to the oil outlet of the second filter.

[0014] Furthermore, the oil inlet valve assembly, the oil outlet valve assembly, and the oil supply drive assembly are each provided in two groups.

[0015] Furthermore, the oil return flow channel is connected to the oil tank through a back pressure valve.

[0016] The beneficial effects of the utility model are as follows: the utility model can be used to supply fuels with low boiling points that need to be pressurized to ensure liquid state (such as dimethyl ether, liquid ammonia, etc.). The structure can keep the fuel pressure in the low-pressure chamber in the pump consistent with the return oil back pressure in the engine system, and at the same time, the high return oil back pressure in the engine return oil liquid circuit can be used to achieve the one-way seal in the one-way valve assembly to achieve normal shutdown of the engine. A plunger oil seal can be arranged at the lower end of the plunger pair to prevent the fuel from leaking into the pump lubrication chamber due to the relatively high fuel pressure in the low-pressure chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the utility model.

[0018] Figure 2 It is a structural schematic diagram of the one-way valve assembly in the utility model. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. The described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0020] In an embodiment of the present utility model, Figure 1 It is a structural schematic diagram provided according to the specific structure of a supply pump for low boiling point fuel of the utility model, such as Figure 1 As shown, the supply pump 8 of the low boiling point fuel of the utility model specifically includes:

[0021] An oil inlet metering valve 1, an oil inlet valve assembly 5, an oil outlet valve assembly 6, an oil supply drive assembly and a one-way oil return valve assembly 7. The oil inlet of the oil inlet metering valve 1 is connected to the oil tank, the oil outlet of the oil inlet metering valve 1 is connected to the oil inlet of the oil inlet valve assembly 5, the oil outlet of the oil inlet valve assembly 5 is connected to the oil supply flow channel 16, one end of the oil supply flow channel 16 is connected to the oil supply drive assembly, the other end of the oil supply flow channel 16 is connected to the oil inlet of the oil outlet valve assembly 6, the oil inlet of the one-way oil return valve assembly 7 is connected to the oil supply flow channel 16 through the low-pressure chamber flow channel 9 in the pump, the oil outlet of the one-way oil return valve assembly 7 is connected to the oil return flow channel 17, and the oil return flow channel 17 is connected to the oil tank.

[0022] In one embodiment of the utility model, the oil supply drive assembly includes: a camshaft 2, a tappet body 3 and a plunger pair 4, the camshaft 2 is installed at one end of the tappet body 3, and the other end of the tappet body 3 is connected to the plunger pair 4.

[0023] In one embodiment of the utility model, the plunger couple 4 comprises: a plunger sleeve 4-1, a plunger 4-2, a plunger oil seal 4-3 and a plunger cavity 10, one end of the plunger 4-2 is connected to the tappet body 3, the plunger sleeve 4-1 is sleeved on the plunger 4-2, the plunger oil seal 4-3 is arranged at one end of the plunger sleeve 4-1 close to the tappet body 3 and is slidably connected to the plunger 4-2, the plunger cavity 10 is arranged at one end of the plunger sleeve 4-1 away from the tappet body 3, and the other end of the plunger 4-2 is placed in the plunger cavity 10. In the plunger couple 4, the plunger oil seal 4-3 can be selectively arranged at the lower end of the plunger sleeve 4-1 according to the hydraulic and physical properties of the fuel to seal the fuel leaking from the gap between the plunger sleeve 4-1 and the plunger 4-2 to prevent the fuel from leaking into the lubrication cavity of the supply pump.

[0024] In one embodiment of the present invention, Figure 2As shown, the one-way oil return valve assembly 7 includes: an oil return valve seat 7-1, a sealing valve ball 7-2 and a cover plate 7-3. The sealing valve ball 7-2 is arranged in the oil return valve seat 7-1, and the cover plate 7-3 is fixedly connected to the sealing valve ball 7-2, specifically by interference fit, threaded connection, riveting, etc. An oil inlet hole 11 is arranged at one end of the oil return valve seat 7-1 away from the cover plate 7-3, and a flow hole 13 is arranged on the cover plate 7-3. The oil inlet hole 11 is connected to the low-pressure chamber flow channel 9 in the pump, the flow hole 13 is connected to the oil return channel 15 of the oil return joint, and the oil return joint is connected to the oil return flow channel 17. Among them, the contact surface between the oil return valve seat 7-1 and the sealing valve ball 7-2 is a sealing cone surface 12, and the reference numeral 14 represents the fixed connection surface between the oil return valve seat 7-1 and the cover plate 7-3. The one-way oil return valve assembly 7 is arranged between the pump low-pressure chamber flow channel 9 and the oil return flow channel 17. The oil inlet hole 11 on the oil return valve seat 7-1 is communicated with the pump low-pressure chamber flow channel 9. The sealing valve ball 7-2 is placed between the oil return valve seat 7-1 and the cover plate 7-3 and contacts the sealing cone surface 12 on the oil return valve seat 7-1. The cover plate 7-3 is tightly fixed on the oil return valve seat 7-1 through the fixed connection surface 14 between the oil return valve seat 7-1 and the cover plate 7-3. The flow hole 13 on the cover plate 7-3 is communicated with the oil return channel 15 of the oil return joint.

[0025] In one embodiment of the utility model, the oil inlet of the oil inlet metering valve 1 is sequentially connected to the first filter 18, the oil pump 19 and the second filter 20. The liquid fuel with a certain pressure provided by the oil pump enters the supply pump assembly after being filtered by the filter, enters the oil supply flow channel 16 after passing through the oil inlet metering valve 1, and then enters the low-pressure chamber flow channel 9 in the pump. At the same time, the return oil flow channel 17 is connected to the oil outlet of the second filter 20, so that the return oil flow channel 17 has a certain pressure.

[0026] In one embodiment of the present utility model, the oil inlet valve assembly 5, the oil outlet valve assembly 6, and the oil supply drive assembly are each provided in two groups. It should be noted that the specific number of settings can be expanded according to actual conditions.

[0027] In one embodiment of the utility model, the oil return flow channel 17 is connected to the fuel tank through a back pressure valve 21. In the fuel supply system of the engine, the oil return flow channel 17 is arranged with a back pressure valve to ensure that a certain liquid pressure is maintained in the entire oil return flow channel so that the fuel in the oil return flow channel remains in liquid state.

[0028] The working principle of the utility model is as follows:

[0029] When the external driving camshaft 2 rotates, the camshaft 2 drives the tappet body 3 to move up and down, and the tappet body 3 pushes the plunger 4-2 to reciprocate in the plunger sleeve 4-1, and the volume of the plunger cavity 10 also changes accordingly. When the plunger 4-2 moves downward, the volume of the plunger cavity 10 increases, the pressure in the cavity decreases, the oil inlet valve assembly 5 opens under the action of the hydraulic pressure difference on both sides, and the fuel enters the plunger cavity 10. When the plunger 4-2 moves upward, the volume of the plunger cavity 10 decreases, the fuel pressure in the cavity increases, and the oil inlet valve assembly 5 closes under the action of the hydraulic pressure difference on both sides. The pressurized fuel pushes the oil outlet valve assembly 6 and flows to the oil outlet of the supply pump.

[0030] When the supply pump is in normal working condition, the fuel liquid pressure in the low-pressure chamber flow channel 9 in the pump is higher than the oil return back pressure set by the engine fuel supply system. At this time, the sealing valve ball 7-2 is pushed open, the pump low-pressure chamber flow channel 9 is connected to the oil return flow channel 15, and the fuel pressure in the low-pressure chamber flow channel 9 is maintained above a certain pressure value to ensure the normal operation of the supply pump. When the engine needs to enter the oil stop condition, the oil inlet metering valve 1 stops working first, and the fuel liquid pressure in the low-pressure chamber flow channel 9 in the pump is lower than the fuel return oil back pressure in the system oil return flow channel. The sealing valve ball 7-2 will be pressed against the sealing cone surface 12 of the oil return valve seat 7-1 under the action of the pressure difference on both sides, and the fuel in the oil return pipeline is blocked from reversely entering the low-pressure chamber of the oil supply pump, ensuring that the supply pump stops supplying oil in time.

[0031] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to examples, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A feed pump for low boiling point fuel, characterized in that: include: An oil inlet metering valve (1), an oil inlet valve assembly (5), an oil outlet valve assembly (6), an oil supply drive assembly and a one-way oil return valve assembly (7), The oil inlet of the oil inlet metering valve (1) is connected to the oil tank, the oil outlet of the oil inlet metering valve (1) is connected to the oil inlet of the oil inlet valve assembly (5), the oil outlet of the oil inlet valve assembly (5) is connected to the oil supply flow channel (16), one end of the oil supply flow channel (16) is connected to the oil supply drive assembly, the other end of the oil supply flow channel (16) is connected to the oil inlet of the oil outlet valve assembly (6), the oil inlet of the one-way oil return valve assembly (7) is connected to the oil supply flow channel (16) via the low-pressure chamber flow channel (9) in the pump, the oil outlet of the one-way oil return valve assembly (7) is connected to the oil return flow channel (17), and the oil return flow channel (17) is connected to the oil tank.

2. The supply pump for low boiling point fuel according to claim 1, characterized in that The oil supply drive assembly comprises: a camshaft (2), a tappet body (3) and a plunger pair (4); the camshaft (2) is mounted on one end of the tappet body (3), and the other end of the tappet body (3) is connected to the plunger pair (4).

3. The supply pump for low boiling point fuel according to claim 2, characterized in that The plunger pair (4) comprises: a plunger sleeve (4-1), a plunger (4-2), a plunger oil seal (4-3) and a plunger cavity (10); one end of the plunger (4-2) is connected to the tappet body (3); the plunger sleeve (4-1) is sleeved on the plunger (4-2); the plunger oil seal (4-3) is arranged at one end of the plunger sleeve (4-1) close to the tappet body (3) and is slidably connected to the plunger (4-2); the plunger cavity (10) is arranged at one end of the plunger sleeve (4-1) away from the tappet body (3); and the other end of the plunger (4-2) is placed in the plunger cavity (10).

4. The supply pump for low boiling point fuel according to claim 1, characterized in that The one-way oil return valve assembly (7) comprises: an oil return valve seat (7-1), a sealing valve ball (7-2) and a cover plate (7-3); the sealing valve ball (7-2) is arranged in the oil return valve seat (7-1); the cover plate (7-3) is fixedly connected to the sealing valve ball (7-2); an oil inlet hole (11) is arranged at one end of the oil return valve seat (7-1) facing away from the cover plate (7-3); and the cover plate (7-3) is provided with a flow hole (13).

5. The supply pump for low boiling point fuel according to claim 4, characterized in that The oil inlet hole (11) is in communication with the low-pressure chamber flow channel (9) in the pump, the flow hole (13) is in communication with the oil return channel of the oil return joint, and the oil return joint is in communication with the oil return flow channel (17).

6. The supply pump for low boiling point fuel according to claim 4, characterized in that A sealing cone surface (12) is provided in the oil return valve seat (7-1), and the sealing valve ball (7-2) is in contact with the sealing cone surface (12).

7. The supply pump for low boiling point fuel according to claim 1, characterized in that The oil inlet of the oil inlet metering valve (1) is connected in sequence to a first filter (18), an oil delivery pump (19) and a second filter (20).

8. The supply pump for low boiling point fuel according to claim 1, characterized in that The oil return passage (17) is connected to the oil outlet of the second filter (20).

9. The supply pump for low boiling point fuel according to claim 1, characterized in that The oil inlet valve assembly (5), the oil outlet valve assembly (6), and the oil supply drive assembly are each provided in two groups.

10. The supply pump for low boiling point fuel according to claim 1, characterized in that The oil return passage (17) is connected to the oil tank via a back pressure valve (21).

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