Diesel engine low-speed combustion-supporting device and diesel engine

Abstract

The low-speed combustion-supporting device is installed between an outlet of a fuel oil injection pump and an oil injection nozzle and comprises a high-pressure storage tank, a three-way connector and a high-pressure one-way valve, and the high-pressure one-way valve comprises a piston seat, a piston, a spring and a spring force regulator; when the spring is compressed, the piston is separated from the piston seat, and the high-pressure one-way valve is opened; when the spring is not compressed, the piston is matched with the piston seat, and the high-pressure one-way valve is closed; the inner diameter of the piston seat is equal to or larger than that of the fuel injection pump piston. When the diesel engine runs at an idle speed, the closed high-pressure one-way valve introduces fuel oil flowing out of the injection pump into the high-pressure oil storage tank for temporary storage, and when slow-flow fuel enters the high-pressure oil storage tank, air in the high-pressure oil storage tank is converted into compressed air. When the pressure exceeds the preset spring force, the high-pressure one-way valve is opened, and the fuel stored in the high-pressure oil storage tank and the entering slow-flow fuel flow out of the nozzle at higher speed and higher pressure. The fuel oil spraying quality of the diesel engine in idle speed operation can be improved, the structure is simple, and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of diesel engine technology, and in particular to a technology for improving poor fuel atomization at low speeds in diesel engines. Background Technology

[0002] Poor fuel atomization at low engine speeds is a major cause of incomplete combustion and high emissions in diesel engines. For example, emissions are high when a vehicle is stationary at a traffic light or while the engine is still running during traffic jams. During gear shifts, the engine speed drops to idle, where the pumping speed is slow, resulting in low injection pressure at the injectors and consequently poor fuel atomization. Poor fuel spray quality at low engine speeds is an inherent problem in inline pump diesel engines.

[0003] High-pressure common rail (HPL) is an advanced fuel injection technology primarily used in diesel engines. This system stores and distributes high-pressure fuel to individual injectors via a common rail (high-pressure rail), enabling precise control of fuel injection. A typical HPL system includes a high-pressure rail for high-pressure fuel storage and distribution, electronically controlled injectors, pressure sensors, and an electronic control unit (ECU). The ECU collects engine operating parameters, calculates the required injection quantity and timing, and sends control signals to the injectors. HPL systems offer more precise fuel injection control and address the problem of poor spray quality at low engine speeds, thus reducing harmful emissions. However, HPL systems are expensive and not suitable for some small diesel engines. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies of the prior art by proposing a low-cost diesel engine low-speed combustion-enhancing device and diesel engine that improves the quality of engine fuel spray in the engine idling state.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: A low-speed combustion-supporting device for a diesel engine is provided, comprising a high-pressure storage tank, a three-way connector, and a high-pressure one-way valve. The high-pressure storage tank is connected to a first end of the three-way connector, a second end of the three-way connector is connected to a first end of the high-pressure one-way valve, a third end of the three-way connector is connected to the outlet of the engine's fuel injection pump, and the other end of the high-pressure one-way valve is connected to the engine's fuel injector. The high-pressure storage tank includes a high-pressure relief valve and a high-pressure tank body, the high-pressure relief valve being fixed to the high-pressure tank body by a threaded connection. The surface of the high-pressure relief valve has through holes for fuel inlet and outlet. The high-pressure one-way valve housing includes, from inlet to outlet, a piston seat, a piston, and a spring. A spring and a spring force adjuster are used; one end of the spring is connected to the spring force adjuster, and the other end of the spring is connected to the piston; when the spring is compressed, the piston disengages from the piston seat, and the high-pressure one-way valve opens; when the spring is not compressed, the piston engages with the piston seat, and the high-pressure one-way valve closes; the inner diameter of the piston seat is equal to or greater than the inner diameter of the piston of the engine's fuel injection pump; when the diesel engine is idling, under the action of the spring force, the piston engages with the piston seat, and the high-pressure one-way valve closes. The closed high-pressure one-way valve introduces the fuel flowing out of the injection pump into the high-pressure storage tank for temporary storage. When slow-flow fuel enters, the air in the high-pressure storage tank is converted into compressed air; when the pressure on the high-pressure one-way valve exceeds the preset spring force, the high-pressure one-way valve opens, and the stored fuel and the entering slow-flow fuel flow out of the nozzle at high speed.

[0006] Furthermore: A bearing sleeve is provided between the inner wall of the high-pressure one-way valve housing and the outer wall of the piston to prevent piston wear.

[0007] A locking disc device is provided at the end of the spring force adjuster that is away from the spring to prevent the spring force adjuster from moving.

[0008] It also includes an adapter tube with external threads at both ends. One end of the adapter tube is threaded to a tee connector, and the other end is threaded to the inlet of the high-pressure check valve.

[0009] The high-pressure check valve outlet is provided with an adapter tube, which has an external thread and is threadedly connected to the high-pressure check valve outlet.

[0010] A diesel engine is provided, including a fuel injection pump, a fuel injector, and the aforementioned low-speed combustion-supporting device for the diesel engine, wherein the low-speed combustion-supporting device is installed between the fuel injection pump outlet and the fuel injector, and the high-pressure storage tank is installed vertically.

[0011] Compared with existing technologies, this invention improves the fuel spray quality at low speeds in diesel engines, promoting more complete fuel combustion, thereby reducing smoke emissions and achieving energy savings and environmental protection. Furthermore, the low-speed combustion aid for diesel engines does not require electronic control devices, is relatively simple compared to high-pressure common rail structures, and has extremely low cost. It can be widely applied to low-cost diesel engines, such as those suitable for installation on agricultural tractors. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of an embodiment of the low-speed combustion-supporting device for diesel engines of the present invention; Figure 2 This is a schematic diagram of Pascal's Law. Figure 3 This is a schematic diagram of the high-pressure storage tank of the low-speed combustion-supporting device for diesel engines of the present invention; Figure 4 This is a schematic diagram of the high-pressure relief valve of the high-pressure storage tank.

[0013] Reference numerals: 1. High-pressure check valve; 1A. High-pressure check valve housing; 2. Spring force adjuster; 3. Locking disc; 4. Locking disc nut; 5. Spring; 6. Piston; 7. Bearing sleeve; 8. Piston seat; 9. First adapter tube; 10. Second adapter tube; 11. High-pressure relief valve; 12. Through hole; 13. High-pressure tank; 14. T-connector; 15. Fuel injector; 15A. Spray; A. Piston of fuel injection pump. Detailed Implementation

[0014] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0015] A low-speed combustion assist device for a diesel engine, installed between the fuel injection pump outlet and the fuel injector, includes a high-pressure storage tank, a three-way connector 14, and a high-pressure check valve 1. Figure 1 As shown, the high-pressure storage tank is vertically positioned and connected to the upper vertical end of the three-way connector 14. One horizontal end of the three-way connector 14 is connected to one end of the high-pressure one-way valve 1, and the other horizontal end of the three-way connector 14 is used to connect to the fuel injection pump outlet of the engine. The other end of the high-pressure one-way valve is used to connect to the fuel injector 15.

[0016] Both the high-pressure storage tank and the high-pressure check valve are detachably connected to a three-way connector. This allows for easy replacement of the high-pressure cylinder and the high-pressure check valve for engines with different performance parameters. In this embodiment, the high-pressure cylinder 1 is connected to the three-way connector 4 via a thread, and the high-pressure check valve 2 is also connected to the three-way connector 4 via a thread.

[0017] like Figure 1As shown, the high-pressure check valve 1 includes a housing 1A, inside which are sequentially an oil inlet, a piston seat 8, a piston 6, a spring 5, a spring force adjuster 2, and an oil outlet. Between the three-way connector and the high-pressure check valve inlet, a first adapter tube 9 with external threads at both ends is provided. One end of the adapter tube is threaded to the three-way connector, and the other end is threaded to the high-pressure check valve inlet. A second adapter tube 10 is provided at the high-pressure check valve outlet, and the second adapter tube 10 is threadedly fastened to the inner wall of the high-pressure check valve housing through its external threads. One end of the spring 5 is connected to the spring force adjuster 2, and the other end is connected to the piston 6. When the spring 5 is compressed, the piston 6 moves to the left and disengages from the piston seat 8, at which point the high-pressure check valve 1 opens. When the spring is not compressed, the piston 6 engages with the piston seat 8, at which point the high-pressure check valve 1 closes.

[0018] like Figure 1 As shown, a bearing sleeve is provided between the inner wall of the housing and the outer wall of the piston to prevent piston wear. A locking disc device 4 is provided at the end of the spring force adjuster 2 away from the spring to prevent the spring force adjuster from moving.

[0019] The cross-sectional area of ​​piston 6 is determined by the inner diameter of piston seat 8. The diameter of piston seat 8 is equal to or greater than the diameter of piston A of the engine's fuel injection pump. When the diameter of piston seat 8 is greater than the diameter of piston A of the fuel injection pump, the engine load can be reduced without affecting the piston stroke.

[0020] According to Pascal's Law, due to the fluidity of liquids, a pressure change occurring in a portion of a stationary fluid in a closed container will be transmitted in all directions with constant magnitude. Applying a certain pressure to one piston in a hydraulic system will necessarily produce the same pressure increase on the other piston. Assuming the area A2 of the second piston is 10 times that of the first piston A1, then the force acting on the second piston will increase to 10 times that of the first piston, F2 = 10F1, while the pressure on both pistons will be equal. Figure 2 As shown, this can be expressed by the formula: F1 / A1=F2 / A2.

[0021] Since A2 is 10 times the area of ​​A1, a 1 cm stroke of the piston acted upon by F2 will produce a 10 cm stroke of the piston acted upon by F1, D1 = 10D2. That is, a larger diameter piston pushing a smaller diameter piston will produce a greater piston stroke. The fuel injection quantity is a function of the piston stroke; the greater the piston stroke, the greater the fuel injection quantity. A larger diameter piston pushing a smaller diameter piston will cause the smaller diameter piston to produce a greater stroke, resulting in excessive fuel injection and affecting spray quality. Therefore, to avoid excessive fuel injection affecting spray quality, the diameter of the piston seat 8 cannot be smaller than the diameter of the piston A of the engine's fuel injection pump, but can be equal to or larger than the diameter of the piston A of the engine's fuel injection pump.

[0022] When the diesel engine is idling, the closed high-pressure check valve directs fuel from the injection pump into the high-pressure reservoir for temporary storage. When slow-flowing fuel enters, the air in the reservoir is converted into compressed air; when the pressure of the high-pressure check valve exceeds a preset spring force, the valve opens. The stored fuel and the incoming slow-flowing fuel flow out of the nozzle at a higher speed and pressure (the spring force can vary). When returning to normal operation, the high-pressure check valve opens, and fuel flowing at high speed from the injection pump and high-pressure reservoir is injected through the high-pressure check valve from the injector nozzle. This invention not only improves the fuel atomization quality of low-speed diesel engines but also increases the injection pressure—exceeding the standard 160 Pa—to improve atomization. Most importantly, it has a simple structure and low cost.

[0023] like Figure 1 , Figure 3 and Figure 4 As shown, the high-pressure storage tank includes a high-pressure relief valve 11 and a high-pressure tank body 13. The high-pressure relief valve 11 is a standard high-pressure relief valve with a through-hole 12 for fuel inlet and outlet. The high-pressure relief valve 11 is fixed to the high-pressure tank body 13 by a threaded connection, and the high-pressure tank body 13 is fixed to a tee connector by a thread. When assembled, the fuel below the through-hole 12 of the vertically installed high-pressure relief valve will remain inside the high-pressure storage tank, and this fuel volume will remain unchanged. Only the fuel above the through-hole can be discharged. Therefore, changing the vertical position of the through-hole can change the volume of air trapped inside the high-pressure storage tank, i.e., change the size of the air chamber of the high-pressure storage tank. The size of the air chamber of the high-pressure storage tank can be used as a size guide for the high-pressure storage tank. Engine performance parameters vary from vehicle to vehicle, and a series of high-pressure cylinders with different air chamber sizes can be set up to match engines with different performance parameters. Changing the size and number of through-holes 12 can change the speed of fuel flow in and out. By using larger or smaller relief valves, the size of the air chamber can be further changed.

[0024] Smoke from an inline pump-type diesel engine is caused by the low piston speed of the fuel injection pump. The spring force of the high-pressure check valve prevents slow-moving fuel from flowing out of the nozzle. When the piston speed of the fuel injection pump is low, the slowly flowing fuel is diverted to a cavity inside the high-pressure storage tank for temporary storage. Because the air in the cavity inside the tank is compressible, the slowly flowing fuel can be diverted there without affecting engine operation.

[0025] The purpose of a high-pressure storage tank is to allow slowly flowing fuel to accumulate while the engine is idling, and the energy of the slowly flowing fuel is converted into compressed air in the high-pressure storage tank. Therefore, the tank walls must be able to withstand high pressure.

[0026] A diesel engine, such as Figure 1As shown, it includes a fuel injection pump, a nozzle 15, and a low-speed combustion aid for a diesel engine installed between the fuel injection pump outlet and the fuel injector.

[0027] In some embodiments, the release pressure threshold of the high-pressure check valve can be set by selecting the spring stiffness. The release pressure threshold of the high-pressure check valve can also be set to match the compression ratio of the air inside the high-pressure cylinder. The discharge rate can be determined by setting the outlet diameter of the high-pressure check valve, preferably a higher discharge rate.

[0028] The principle of the low-speed combustion-supporting device and diesel engine of this invention is as follows: 1. The fuel outlet velocity at the fuel injector is directly proportional to the atomization effect; the higher the fuel outlet velocity, the better the atomization effect. 2. Better atomization means producing finer fuel droplets; 3. The finer the fuel droplets, the faster they evaporate, resulting in more complete combustion; 4. When the piston speed of the fuel injection pump is low, the low-speed fuel flowing out of the engine's fuel injection pump is blocked by the high-pressure one-way valve and will not be injected from the injector 15. Instead, it flows into the high-pressure storage tank for temporary storage and compresses air. Only when the diesel engine is in normal operation can the high-speed fuel flowing out of the engine's fuel injection pump force the high-pressure one-way valve to open. Only then can the high-speed fuel flowing out of the engine's fuel injection pump and the high-pressure fuel in the high-pressure storage tank be injected from the injector, ensuring a high fuel outlet velocity and good atomization effect at the injector.

[0029] The diesel engine low-speed combustion assist device of the present invention can be connected to the fuel injection pump outlet of a single-cylinder diesel engine, or one of the diesel engine low-speed combustion assist devices can be connected to the outlet of each plunger sleeve of the fuel injection pump of a multi-cylinder diesel engine.

[0030] In diesel engines equipped with a low-speed combustion-supporting device, the fuel injection pump is isolated from the fuel injectors by the device. Therefore, the injection speed at the fuel injectors is not directly related to engine speed. Consequently, at low engine speeds, the injection pressure at the fuel injectors is unaffected by the piston speed of the fuel injection pump. Only when the engine is at normal operating speed does the high-pressure one-way valve open, creating a high-quality fuel spray (15A), which promotes more complete combustion, reducing smoke emissions and resulting in energy savings and environmental friendliness.

[0031] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and these modifications and substitutions should all fall within the protection scope of the appended claims of the present invention.

Claims

1. A low-speed combustion-supporting device for a diesel engine, comprising a high-pressure storage tank, a three-way connector, and a high-pressure one-way valve, wherein the high-pressure storage tank is connected to a first end of the three-way connector, a second end of the three-way connector is connected to a first end of the high-pressure one-way valve, a third end of the three-way connector is connected to the outlet of the engine's fuel injection pump, and the other end of the high-pressure one-way valve is connected to the engine's fuel injector, characterized in that: The high-pressure storage tank includes a high-pressure relief valve and a high-pressure tank body. The high-pressure relief valve is fixed to the high-pressure tank body by a threaded connection, and the surface of the high-pressure relief valve is provided with a through hole for fuel inlet and outlet. The high-pressure one-way valve housing includes, from inlet to outlet, a piston seat, a piston, a spring, and a spring force adjuster. One end of the spring is connected to the spring force adjuster, and the other end is connected to the piston. When the spring is compressed, the piston disengages from the piston seat, and the high-pressure one-way valve opens. When the spring is not compressed, the piston engages with the piston seat, and the high-pressure one-way valve closes. The inner diameter of the piston seat is equal to or greater than the inner diameter of the piston of the engine's fuel injection pump. When the diesel engine is idling, the piston and piston seat are engaged under the action of the spring force, and the high-pressure one-way valve is closed. The closed high-pressure one-way valve introduces the fuel flowing out of the injection pump into the high-pressure storage tank for temporary storage. When slow-flow fuel enters, the air in the high-pressure storage tank is converted into compressed air. When the pressure on the high-pressure one-way valve exceeds the preset spring force, the high-pressure one-way valve opens, and the stored fuel and the entering slow-flow fuel will flow out of the nozzle at high speed.

2. The low-speed combustion-supporting device for a diesel engine according to claim 1, characterized in that: A bearing sleeve is provided between the inner wall of the high-pressure one-way valve housing and the outer wall of the piston to prevent piston wear.

3. The low-speed combustion assist device for a diesel engine according to claim 1, characterized in that: A locking disc device is provided at the end of the spring force adjuster that is away from the spring to prevent the spring force adjuster from moving.

4. The low-speed combustion-supporting device for a diesel engine according to claim 1, characterized in that: It also includes an adapter tube with external threads at both ends. One end of the adapter tube is threaded to a tee connector, and the other end is threaded to the inlet of the high-pressure check valve.

5. The low-speed combustion assist device for a diesel engine according to claim 1, characterized in that: The high-pressure check valve outlet is provided with an adapter tube, which has an external thread and is threadedly connected to the high-pressure check valve outlet.

6. A diesel engine, comprising a fuel injection pump and fuel injectors, characterized in that: It also includes a low-speed combustion-supporting device for a diesel engine as described in any one of claims 1 to 5, wherein the low-speed combustion-supporting device for a diesel engine is installed between the fuel injection pump outlet and the fuel injector of the engine, and the high-pressure storage tank is installed vertically.

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