Automatic recovery device for fuel oil return of monoblock pump diesel engine

Abstract

The utility model discloses an automatic recovery device for fuel oil return of a monoblock pump diesel engine, relates to the technical field of diesel engines, and solves the technical problems that the fuel oil return easily overflows to cause pollution and harm to safety due to the fact that an oil discharge switch cannot be turned on manually in time to discharge the fuel oil return. The device comprises a liquid level sensing module, an electric oil well pump, an oil tank and a control circuit, the liquid level sensing module is installed in the oil tank, an oil return inlet is formed in the top of the oil tank, the electric oil well pump is installed on the outer side of the oil tank, and the oil pumping end of the electric oil well pump is communicated with an oil outlet of the oil tank; the liquid level sensing module and the electric oil well pump are both electrically connected with the control circuit. According to the utility model, fuel return discharged by the engine can be effectively collected and treated, and the pollution to the environment and the harm to the safety are reduced, so that the requirements of environmental protection laws and regulations are met.

Description

Technical Field

[0001] This utility model relates to the field of diesel engine technology, and more specifically, it relates to an automatic fuel return recovery device for a unit pump diesel engine. Background Technology

[0002] The function of the fuel spill collection tank is to collect and store the return fuel generated by the fuel pump. The mechanism of return fuel generation is explained below:

[0003] The plunger and plunger sleeve are precision-fitted components with a clearance of 2-10 micrometers. During operation, the high-pressure fuel generated at the top of the plunger can reach over 1000 kg. This high-pressure fuel leaks downwards through the plunger assembly clearance to the zero-backpressure return oil passage, where it is discharged. Simultaneously, the pump's cam chamber is filled with engine oil. During operation, the pump roller assembly converts the camshaft's rotational motion into the plunger's vertical linear motion. This rapid up-and-down movement of the plunger scrapes upwards the engine oil. The engine oil carried upwards through the plunger clearance mixes with the leaking diesel fuel as it flows out through the zero-backpressure return oil passage (see...). Figure 1 The diagram shows the oil return passage structure of the engine unit pump. On the other hand, the small amount of oil carried into the lower surface of the plunger can also prevent the plunger from sticking due to insufficient lubrication.

[0004] To prevent diesel and engine oil from mixing, and to protect the engine and fuel pump, large-diameter fuel pumps employ a fuel return port design to isolate and drain leaks. Currently, Bosch and MAN both domestically and internationally use this structure in their large marine fuel systems. Most existing fuel leak collection systems rely on manual draining.

[0005] The reason why manually draining fuel leak collection tanks is inconvenient is that the return fuel from the unit pump flows into the collection tank, which has a limited capacity. When a significant amount of return fuel is observed through the level gauge, the drain valve must be manually opened to remove it. If the return fuel is not removed in time, it will overflow from the vent at the top of the collection tank. Summary of the Invention

[0006] The technical problem to be solved by this utility model is to provide an automatic fuel return recovery device for a single-pump diesel engine, which addresses the shortcomings of the existing technology and solves the technical problem that the fuel return is easily overflowed due to insufficient time to manually open the vent switch to remove the return oil, resulting in pollution and safety hazards.

[0007] The present invention discloses an automatic fuel return recovery device for a single-unit pump diesel engine. The device includes a liquid level sensing module, an electric oil pump, an oil tank, and a control circuit. The liquid level sensing module is installed in the oil tank, and the top of the oil tank has a return oil inlet. The electric oil pump is installed on the outside of the oil tank, and the oil pumping end of the electric oil pump is connected to the oil outlet of the oil tank. Both the liquid level sensing module and the electric oil pump are electrically connected to the control circuit.

[0008] As a further improvement, a filter element is installed below the oil return inlet.

[0009] Furthermore, the liquid level sensing module includes a detection rod, a first liquid level switch, and a second liquid level switch. The detection rod is fixedly installed in the oil tank, and both the first and second liquid level switches are mounted on the detection rod. Both the first and second liquid level switches are electrically connected to the control circuit.

[0010] Furthermore, a first limiting ring is fixedly installed on the detection rods on both sides of the first liquid level switch, and a second limiting ring is fixedly installed on the detection rods on both sides of the second liquid level switch. The first liquid level switch and the second liquid level switch are slidably connected to the detection rods.

[0011] Furthermore, the first liquid level switch is located below the filter element, and the second liquid level switch is at the same horizontal level as the oil outlet of the oil tank.

[0012] Furthermore, the control circuit includes a power supply and a relay. The positive terminal of the power supply is electrically connected to a first liquid level switch, the first liquid level switch is electrically connected to a second liquid level switch, the second liquid level switch is connected in series with the coil of the relay, and the coil of the relay is electrically connected to the negative terminal of the power supply.

[0013] The positive terminal of the power supply is electrically connected to the first normally open switch and the second normally open switch of the relay. The first normally open switch of the relay is electrically connected to the connection between the first liquid level switch and the second liquid level switch. The second normally open switch of the relay is connected in series with the motor of the electric oil pump. The motor of the electric oil pump is electrically connected to the negative terminal of the power supply.

[0014] Furthermore, a fuse is electrically connected between the positive terminal of the power supply and the first liquid level switch.

[0015] Furthermore, the oil tank is equipped with an oil discharge switch at the oil outlet that starts synchronously with the electric oil pump.

[0016] Furthermore, the electric oil pump is mounted on the outside of the oil tank via clamps.

[0017] Furthermore, the top of the oil tank is provided with a pressure relief port, and a pressure relief valve is installed in the pressure relief port.

[0018] Beneficial effects

[0019] The advantages of this utility model are:

[0020] This invention comprises a detection rod, a first level switch, a second level switch, an electric oil pump, and a control circuit. The detection rod is installed inside the oil tank. Both the first and second level switches are mounted on the detection rod. The electric oil pump is installed outside the oil tank, with its suction end connected to the oil outlet of the tank. The first and second level switches, as well as the electric oil pump, are electrically connected to the control circuit. The oil in the tank triggers the first and second level switches, causing the control circuit to operate the electric oil pump. This effectively collects and processes the fuel return from the engine. This invention reduces environmental pollution, thus complying with environmental regulations. By recycling leaked fuel, it reduces dependence on crude oil resources, enabling resource reuse, reducing fuel recovery costs, and improving work efficiency. Timely removal of leaked fuel ensures smooth fuel injection within the engine, preventing engine malfunctions caused by abnormal fuel atomization, thereby reducing engine maintenance and replacement costs. Harmful substances in the returned fuel can accelerate the wear of engine components; this invention reduces the accumulation of these harmful substances, thereby extending engine lifespan and improving engine reliability. Attached Figure Description

[0021] Figure 1 A schematic diagram of fuel leakage in the existing unit pump return oil passage structure of an engine.

[0022] Figure 2 This is a schematic diagram of the automatic fuel return and recovery device of this utility model;

[0023] Figure 3 This is a schematic diagram of the control circuit of the automatic fuel return and recovery device of this utility model.

[0024] The components are: 1-detection rod, 2-first liquid level switch, 3-second liquid level switch, 4-electric oil pump, 5-oil tank, 6-oil drain switch, 7-clamp, 8-oil return inlet, 9-filter element, 10-pressure relief valve, 11-first limit ring, 12-second limit ring, U-power supply, KA-relay coil, KA1-first normally open switch of relay, KA2-second normally open switch of relay, M-motor of electric oil pump, FU-fuse. Detailed Implementation

[0025] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0026] See Figures 2-3 This utility model discloses an automatic fuel return recovery device for a single-pump diesel engine. The device includes a fuel tank 5, a liquid level sensing module, an electric oil pump 4, and a control circuit. The liquid level sensing module includes a detection rod 1, a first liquid level switch 2, and a second liquid level switch 3. The detection rod 1 is installed inside the fuel tank 5, and both the first and second liquid level switches 2 and 3 are mounted on the detection rod 1. The electric oil pump 4 is installed outside the fuel tank 5, and its suction end is connected to the fuel outlet of the fuel tank 5. The first liquid level switch 2, the second liquid level switch 3, and the electric oil pump 4 are all electrically connected to the control circuit. Both the first and second liquid level switches 2 and 3 are normally open switches.

[0027] The top of the oil tank 5 is provided with an oil return inlet 8, and a filter element 9 is installed below the oil return inlet 8. The filter element 9 is mainly used for filtering oil, removing worn metal powder and other mechanical impurities to keep the oil circuit clean and extend the service life of the equipment.

[0028] The control circuit includes a power supply U and a relay. The positive terminal of the power supply U is electrically connected to the first liquid level switch 2. The first liquid level switch 2 is electrically connected to the second liquid level switch 3. The second liquid level switch 3 is connected in series with the coil KA of the relay. The coil KA of the relay is electrically connected to the negative terminal of the power supply U. When the coil KA of the relay is energized, the first normally open switch KA1 and the second normally open switch KA2 of the relay close simultaneously.

[0029] The positive terminal of the power supply U is electrically connected to the first normally open switch KA1 and the second normally open switch KA2 of the relay. The first normally open switch KA1 of the relay is electrically connected to the first liquid level switch 2 and the second liquid level switch 3. The second normally open switch KA2 of the relay is connected in series with the motor M of the electric oil pump. The motor M of the electric oil pump is electrically connected to the negative terminal of the power supply U. The electric oil pump 4 is used to pump the return oil away from the oil tank 5.

[0030] A fuse FU is electrically connected between the positive terminal of the power supply U and the first liquid level switch 2. When the fuse is correctly installed in the circuit, it will melt and break the current when the current abnormally rises to a certain level or temperature, thus protecting the circuit's safe operation.

[0031] The oil outlet of oil tank 5 is equipped with an oil discharge switch 6 that starts synchronously with the electric oil pump 4.

[0032] The first level switch 2 is located below the filter element 9 to prevent damage caused by prolonged immersion in excessively high liquid levels. The second level switch 3 is at the same level as the oil outlet of the oil tank 5 to prevent the electric oil pump 4 from failing to contact the collected return oil due to excessively low liquid levels. The first level switch 2 is located above the second level switch 3. The first level switch 2 is a high-level switch, and the second level switch 3 is a low-level switch. Both the first level switch 2 and the second level switch 3 are slidably connected to the detection rod 1, and will float with the return oil level.

[0033] First limiting rings 11 are fixedly installed on the detection rods 1 on both sides of the first liquid level switch 2. The first limiting rings 11 are used to limit the movement of the first liquid level switch 2, so that the first liquid level switch 2 is located below the filter element 9 and above the second liquid level switch 3. Second limiting rings 12 are fixedly installed on the detection rods 1 on both sides of the second liquid level switch 3. The second limiting rings 12 are used to limit the movement of the second liquid level switch 3, so that the second liquid level switch 3 is at the same horizontal level as the oil outlet of the oil tank 5.

[0034] The electric oil pump 4 is mounted on the outside of the oil tank 5 via clamps 7. The electric oil pump 4 can be detached and installed by removing the clamps 7, thereby improving the installation flexibility of the electric oil pump 4.

[0035] The top of the oil tank 5 is provided with a pressure relief port, and a pressure relief valve 10 is installed in the pressure relief port to release the excessive pressure in the oil tank 5.

[0036] The working principle of this utility model is as follows:

[0037] The return oil from the unit pump flows into the oil tank 5 through the return oil inlet 8 and the filter element 9. When the return oil level in the oil tank 5 reaches the second level switch 3 and triggers it, the second level switch 3 closes. However, since the power supply to the relay circuit is mainly controlled by the first level switch 2, the relay is not energized. When the return oil level in the oil tank 5 continues to rise and reaches the first level switch 2 and triggers it, the first level switch 2 closes, the relay coil KA is energized, and the first normally open switch KA1 and the second normally open switch KA2 of the relay close simultaneously. The motor M of the electric oil pump is energized, and the electric oil pump 4 starts working. At the same time, the drain switch 6 opens synchronously, drawing the return oil from the oil tank 5 out of the oil outlet of the oil tank 5.

[0038] As the return oil in oil tank 5 is drawn out, the return oil level in oil tank 5 drops. When the return oil level in oil tank 5 is lower than the first level switch 2, the first level switch 2 returns to its original normally open state. However, since the power supply U can continue to supply power to the coil KA of the relay through the first normally open switch KA1 of the relay, the second level switch 3, the first normally open switch KA1 of the relay, and the second normally open switch KA2 of the relay remain closed. The electric oil pump 4 continues to work and draws the return oil in oil tank 5 out of the oil outlet of oil tank 5.

[0039] When the return oil level in oil tank 5 is lower than the second level switch 3, the second level switch 3 returns to its original normally open state, the relay coil KA is de-energized, the first normally open switch KA1 and the second normally open switch KA2 of the relay return to their original normally open state, and the electric oil pump 4 stops working.

[0040] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present utility model. These modifications and improvements will not affect the effectiveness of the present utility model or the practicality of the patent.

Claims

1. An automatic fuel return recovery device for a single-pump diesel engine, characterized in that, The device includes a liquid level sensing module, an electric oil pump (4), an oil tank (5), and a control circuit. The liquid level sensing module is installed in the oil tank (5). The top of the oil tank (5) is provided with an oil return inlet (8). The electric oil pump (4) is installed on the outside of the oil tank (5) and the oil pump end of the electric oil pump (4) is connected to the oil outlet of the oil tank (5). The liquid level sensing module and the electric oil pump (4) are both electrically connected to the control circuit. The liquid level sensing module includes a detection rod (1), a first liquid level switch (2), and a second liquid level switch (3). The detection rod (1) is fixedly installed in the oil tank (5). The first liquid level switch (2) and the second liquid level switch (3) are both installed on the detection rod (1). The first liquid level switch (2) and the second liquid level switch (3) are both electrically connected to the control circuit.

2. The automatic fuel return recovery device for a single-unit pump diesel engine according to claim 1, characterized in that, A filter element (9) is installed below the oil return inlet (8).

3. The automatic fuel return recovery device for a single-unit pump diesel engine according to claim 1, characterized in that, A first limiting ring (11) is fixedly installed on the detection rod (1) on both sides of the first liquid level switch (2), and a second limiting ring (12) is fixedly installed on the detection rod (1) on both sides of the second liquid level switch (3). The first liquid level switch (2) and the second liquid level switch (3) are slidably connected to the detection rod (1).

4. The automatic fuel return recovery device for a single-unit pump diesel engine according to claim 2, characterized in that, The first liquid level switch (2) is located below the filter element (9), and the second liquid level switch (3) is at the same level as the oil outlet of the oil tank (5).

5. The automatic fuel return recovery device for a single-unit pump diesel engine according to claim 1, characterized in that, The control circuit includes a power supply (U) and a relay. The positive terminal of the power supply (U) is electrically connected to the first liquid level switch (2). The first liquid level switch (2) is electrically connected to the second liquid level switch (3). The second liquid level switch (3) is connected in series with the coil (KA) of the relay. The coil (KA) of the relay is electrically connected to the negative terminal of the power supply (U). The positive terminal of the power supply (U) is electrically connected to the first normally open switch (KA1) and the second normally open switch (KA2) of the relay. The first normally open switch (KA1) of the relay is electrically connected to the connection between the first liquid level switch (2) and the second liquid level switch (3). The second normally open switch (KA2) of the relay is connected in series with the motor (M) of the electric oil pump. The motor (M) of the electric oil pump is electrically connected to the negative terminal of the power supply (U).

6. The automatic fuel return recovery device for a single-unit pump diesel engine according to claim 5, characterized in that, A fuse (FU) is electrically connected between the positive terminal of the power supply (U) and the first liquid level switch (2).

7. The automatic fuel return recovery device for a single-unit pump diesel engine according to claim 1, characterized in that, The oil tank (5) is equipped with an oil discharge switch (6) that starts synchronously with the electric oil pump (4) at the oil outlet.

8. The automatic fuel return recovery device for a single-unit pump diesel engine according to claim 1, characterized in that, The electric oil pump (4) is installed on the outside of the oil tank (5) by means of a clamp (7).

9. The automatic fuel return recovery device for a single-unit pump diesel engine according to claim 1, characterized in that, The top of the oil tank (5) is provided with a pressure relief port, and a pressure relief valve (10) is installed in the pressure relief port.

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