Common rail fuel system of medium-speed diesel engine

Abstract

The utility model discloses a common-rail fuel system of a medium-speed diesel engine, relates to the technical field of fuel systems of diesel engines, and solves the problems of slower rail pressure establishment, unstable rotating speed and difficulty in starting when the diesel engine is at low rotating speed in the prior art. Comprising two high-pressure combined oil pumps, a low-pressure oil pipe, a fuel oil filter, a first high-pressure oil pipe, a distribution block and a common rail pipe, the two high-pressure combined oil pumps are installed on a housing at the front end of the diesel engine, and the high-pressure combined oil pumps are driven through a crankshaft gear; the fuel oil filter is respectively communicated with the high-pressure combined oil pump through the low-pressure oil pipe; the two high-pressure combined oil pumps are respectively communicated with the distribution block through a first high-pressure oil pipe, the distribution block is communicated with a rail-to-fuel injector high-pressure oil pipe through a common rail pipe, and the rail-to-fuel injector high-pressure oil pipe is communicated with an electric control fuel injector. The method has the beneficial effects that rail pressure can be quickly established, and quick starting and low-rotating-speed stable operation of the diesel engine are guaranteed.

Description

A common rail fuel system for medium-speed diesel engines Technical Field

[0001] This utility model relates to the technical field of diesel engine fuel systems, specifically to a common rail fuel system for medium-speed diesel engines. Background Technology

[0002] In the development of medium-speed diesel engine technology, the fuel system has always been a core component determining the performance of a diesel engine. Currently, the fuel system of a medium-speed diesel engine consists of a fuel filter, a fuel camshaft, an injection pump, high-pressure fuel lines, and injectors. The crankshaft rotation drives the camshaft to rotate via gear transmission. The fuel camshaft on the camshaft drives the mechanical unit pump. The plunger in the mechanical unit pump moves up and down to generate high-pressure fuel, which flows from the delivery valve on the mechanical unit pump to the high-pressure fuel lines and finally to the injectors.

[0003] The camshaft drives the high-pressure fuel pump, and its speed is half that of the crankshaft. When starting a medium-speed diesel engine, the engine speed is approximately 240-400 rpm, while the camshaft speed is 120-200 rpm. When the diesel engine is operating at low speeds, due to the characteristics of the mechanical unit pump, it is difficult to quickly establish sufficient rail pressure. Slow rail pressure establishment directly leads to unstable operation and insufficient power output at low operating conditions, affecting not only the engine's efficiency but also increasing fuel consumption and emissions. Therefore, the diesel engine experiences slow rail pressure establishment at low speeds, resulting in unstable speeds and difficulty starting.

[0004] Therefore, this invention proposes a common rail fuel system for medium-speed diesel engines to solve the aforementioned problems. Summary of the Invention

[0005] The purpose of this invention is to provide a common rail fuel system for medium-speed diesel engines, which solves the problems of slow rail pressure build-up, unstable speed, and difficulty in starting diesel engines at low speeds in the prior art.

[0006] The technical solution adopted by this utility model to solve its technical problem is:

[0007] A common rail fuel system for a medium-speed diesel engine includes a high-pressure combined fuel pump, a low-pressure fuel line, a fuel filter, a first high-pressure fuel line, a distribution block, and a common rail. Two high-pressure combined fuel pumps are mounted on the front cover of the diesel engine and are driven by a crankshaft gear. The fuel filter is connected to each of the high-pressure combined fuel pumps via the low-pressure fuel line. The two high-pressure combined fuel pumps are connected to the distribution block via the first high-pressure fuel line. The distribution block is connected to the rail-to-injector high-pressure fuel line via the common rail, and the rail-to-injector high-pressure fuel line is connected to an electronically controlled injector.

[0008] Furthermore, the distribution block includes a left high-pressure oil inlet, a right high-pressure oil inlet, and a high-pressure oil outlet. The left high-pressure oil inlet and the right high-pressure oil inlet are respectively connected to the first high-pressure oil pipe, and the high-pressure oil outlet is connected to the common rail pipe.

[0009] Furthermore, the distribution block is equipped with a solenoid valve and a pressure relief valve, the pressure relief valve being able to release the high-pressure fuel in the distribution block.

[0010] Furthermore, the solenoid valve on the distribution block is connected to compressed air of 0.6 to 0.8 MPa via a pipeline. The air outlet of the solenoid valve is connected to the air inlet of the pressure relief valve. The compressed air can drive the pressure relief valve to work, and the high-pressure oil can be discharged through the pressure relief valve.

[0011] Furthermore, the distribution block is equipped with a detection component for detecting high-pressure fuel leakage, including a high-pressure fuel inlet leakage detection component at the left end, a high-pressure fuel inlet leakage detection component at the right end, a high-pressure fuel pipe from the distribution block to the rail, and a high-pressure fuel outlet leakage detection component, which respectively correspond to detecting the high-pressure fuel inlet at the left end, the high-pressure fuel inlet at the right end, the pressure relief valve, and the high-pressure fuel outlet.

[0012] Furthermore, the electronically controlled fuel injector is electrically connected to the ECU.

[0013] Furthermore, the crankshaft gear drives two high-pressure combined oil pumps through a large transmission ratio.

[0014] In summary, compared with the prior art, the beneficial effects of this utility model are as follows:

[0015] 1. This utility model drives two high-pressure combined oil pumps through crankshaft gears. The high-pressure combined oil pumps quickly pressurize low-pressure fuel into high-pressure fuel, which is then transported to the distribution block for mixing via the first high-pressure oil pipe and flows into the common rail pipe. This rapidly establishes rail pressure, ensuring the diesel engine's rapid start-up and stable operation at low speeds, and avoiding the problem of unstable operation under low operating conditions caused by slow rail pressure establishment.

[0016] 2. The two high-pressure combined oil pumps of this utility model work simultaneously, making the fuel delivery more stable. When one pump fails, the other pump can still maintain a certain fuel supply, ensuring the continuous operation of the diesel engine and the stable operation of the electronic fuel injector.

[0017] 3. The electronic fuel injector of this utility model is electrically connected to the ECU. The ECU can accurately control the injection timing and injection duration of the electronic fuel injector according to the actual operating conditions of the diesel engine, so as to achieve precise fuel injection.

[0018] 4. When the diesel engine of this utility model stops running, the solenoid valve on the distribution block is energized and activated. The connected 0.6-0.8MPa compressed air enters the air inlet of the pressure relief valve through the air outlet of the solenoid valve, driving the pressure relief valve to work and release the high-pressure fuel in the distribution block and high-pressure fuel system, avoiding damage to components caused by residual high pressure and reducing safety risks.

[0019] 5. The distribution block of this utility model is equipped with multiple detection components, which respectively detect whether there is leakage at the left high-pressure oil inlet, the right high-pressure oil inlet, the pressure relief valve and the high-pressure oil outlet, enabling real-time monitoring of the sealing performance of the high-pressure fuel system and improving system operation. Attached Figure Description

[0020] Figure 1 shows the main concept of this utility model;

[0021] Figure 2 is a schematic diagram of the distribution block of this utility model;

[0022] Figure 3 is the left view of Figure 2;

[0023] In the diagram: 1. High-pressure combined oil pump; 2. Low-pressure oil pipe; 3. Fuel filter; 4. First high-pressure oil pipe; 5. Distributor block; 6. Common rail pipe; 7. Rail-to-injector high-pressure oil pipe; 8. Left high-pressure oil inlet; 9. Right high-pressure oil inlet; 10. Distributor block-to-rail high-pressure oil pipe; 11. High-pressure oil outlet leakage detection component; 12. Right high-pressure oil inlet leakage detection component; 13. High-pressure oil outlet; 14. Left high-pressure oil inlet leakage detection component; 15. Solenoid valve outlet; 16. Solenoid valve; 17. Pressure relief valve; 18. Pressure relief valve inlet. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0025] In this application, the terms "upper," "inner," "outer," "middle," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0026] As shown in Figures 1-3, a common rail fuel system for a medium-speed diesel engine includes a high-pressure combined fuel pump 1, a low-pressure fuel line 2, a fuel filter 3, a first high-pressure fuel line 4, a distribution block 5, and a common rail 6. Two high-pressure combined fuel pumps 1 are mounted on the front cover of the diesel engine and are driven by a crankshaft gear. The crankshaft gear drives the two high-pressure combined fuel pumps 1 through a large transmission ratio. The fuel filter 3 is connected to the high-pressure combined fuel pumps 1 via the low-pressure fuel line 2. The two high-pressure combined fuel pumps 1 are connected to the distribution block 5 via the first high-pressure fuel line 4. The distribution block 5 is connected to the rail-to-injector high-pressure fuel line 7 via the common rail 6. The rail-to-injector high-pressure fuel line 7 is connected to the electronically controlled injector (ECU). The electronically controlled injector is electrically connected to the ECU.

[0027] Furthermore, the distribution block 5 includes a left high-pressure oil inlet 8, a right high-pressure oil inlet 9, and a high-pressure oil outlet 13. The left high-pressure oil inlet 8 and the right high-pressure oil inlet 9 are respectively connected to the first high-pressure oil pipe 4, and the high-pressure oil outlet 13 is connected to the common rail pipe 6. The distribution block 5 is equipped with a solenoid valve 16 and a pressure relief valve 17. The pressure relief valve 17 can release the high-pressure fuel in the distribution block 5. The solenoid valve 16 on the distribution block 5 is connected to compressed air of 0.6-0.8 MPa through a pipeline. The air outlet 15 of the solenoid valve is connected to the air inlet of the pressure relief valve 17. The compressed air can drive the pressure relief valve 17 to work, and the high-pressure oil can be discharged through the pressure relief valve 17. The distribution block 5 is equipped with a detection component for detecting high-pressure fuel leakage, including a high-pressure fuel inlet leakage detection component 14 at the left end, a high-pressure fuel inlet leakage detection component 12 at the right end, a high-pressure fuel pipe 10 from the distribution block to the rail, and a high-pressure fuel outlet leakage detection component 11, which respectively correspond to the detection of the high-pressure fuel inlet 8 at the left end, the high-pressure fuel inlet 9 at the right end, the pressure relief valve 17, and the high-pressure fuel outlet 13.

[0028] The working process of this utility model is as follows:

[0029] First, the low-pressure fuel is filtered by the fuel filter 3 and then split into two paths through the low-pressure fuel line 2, which are respectively delivered to two high-pressure combined fuel pumps 1. Then, the crankshaft gear drives the two high-pressure combined fuel pumps 1 through a large transmission ratio. The plunger moves up and down to pressurize the low-pressure fuel into high-pressure fuel. The high-pressure fuel generated by the two high-pressure combined fuel pumps 1 enters through the first high-pressure fuel line 4 from the high-pressure fuel inlet 8 at the left end and the high-pressure fuel inlet 9 at the right end of the distribution block 5. After mixing in the distribution block 5, it flows out from the high-pressure fuel outlet 13. After being stabilized by the common rail pipe 6, it is delivered to the electronic fuel injectors of each cylinder through the high-pressure fuel line 7 from the rail to the injector. The ECU controls the opening time and duration of the electronic fuel injectors according to the operating conditions of the diesel engine to achieve precise fuel injection.

[0030] High-pressure fuel is collected at the left and right inlets of distribution block 5 and flows from high-pressure fuel outlet 13 to common rail 6. At this time, solenoid valve 16 is not energized and pressure relief valve 17 is closed, which does not affect fuel delivery. Then, ECU controls solenoid valve 16 to be energized to connect compressed air of 0.6-0.8MPa. The compressed air enters the air inlet of pressure relief valve 17 through solenoid valve outlet 15, driving pressure relief valve 17 to open. Then, residual high-pressure fuel in distribution block 5 and high-pressure fuel system is discharged through pressure relief valve 17 to prevent high pressure residue from damaging components. Then, the leakage detection components on distribution block 5 monitor the sealing of each interface in real time. The left high-pressure fuel inlet leakage detection component 14 monitors whether there is oil leakage at the left inlet; the right high-pressure fuel inlet leakage detection component 12 monitors whether there is oil leakage at the right inlet; the high-pressure fuel outlet leakage detection component 11 monitors whether there is oil leakage at the high-pressure fuel outlet 13; the detection component at the position of pressure relief valve 17 on the high-pressure fuel pipe 10 from distribution block to common rail monitors whether pressure relief valve 17 is leaking.

Claims

1. A common rail fuel system for a medium-speed diesel engine, comprising a high-pressure combined fuel pump (1), a low-pressure fuel line (2), a fuel filter (3), a first high-pressure fuel line (4), a distribution block (5), and a common rail (6), characterized in that, Two high-pressure combined oil pumps (1) are installed on the front cover of the diesel engine. The high-pressure combined oil pumps (1) are driven by crankshaft gears. The fuel filter (3) is connected to the high-pressure combined oil pumps (1) through the low-pressure oil pipe (2). The two high-pressure combined oil pumps (1) are connected to the distribution block (5) through the first high-pressure oil pipe (4). The distribution block (5) is connected to the rail-to-injector high-pressure oil pipe (7) through the common rail pipe (6). The rail-to-injector high-pressure oil pipe (7) is connected to the electronically controlled injector.

2. The common rail fuel system for medium-speed diesel engines according to claim 1, characterized in that, The distribution block (5) includes a left high-pressure oil inlet (8), a right high-pressure oil inlet (9), and a high-pressure oil outlet (13). The left high-pressure oil inlet (8) and the right high-pressure oil inlet (9) are respectively connected to the first high-pressure oil pipe (4), and the high-pressure oil outlet (13) is connected to the common rail pipe (6).

3. The common rail fuel system for medium-speed diesel engines according to claim 2, characterized in that, The distribution block (5) is equipped with a solenoid valve (16) and a pressure relief valve (17), which can release the high-pressure fuel in the distribution block (5).

4. The common rail fuel system for medium-speed diesel engines according to claim 3, characterized in that, The solenoid valve (16) on the distribution block (5) is connected to compressed air of 0.6 to 0.8 MPa through a pipeline. The air outlet (15) of the solenoid valve is connected to the air inlet (18) of the pressure relief valve. The compressed air can drive the pressure relief valve (17) to work, and the high-pressure oil can be discharged through the pressure relief valve (17).

5. The common rail fuel system for medium-speed diesel engines according to claim 4, characterized in that, The distribution block (5) is equipped with a detection component for detecting high-pressure fuel leakage, including a high-pressure fuel inlet leakage detection component (14) at the left end, a high-pressure fuel inlet leakage detection component (12) at the right end, a high-pressure fuel pipe (10) from the distribution block to the rail, and a high-pressure fuel outlet leakage detection component (11), which correspond to the detection of the high-pressure fuel inlet (8) at the left end, the high-pressure fuel inlet (9) at the right end, the pressure relief valve (17), and the high-pressure fuel outlet (13), respectively.

6. The common rail fuel system for medium-speed diesel engines according to claim 1, characterized in that, The electronic fuel injector is electrically connected to the ECU.

7. The common rail fuel system for medium-speed diesel engines according to claim 1, characterized in that, The crankshaft gear drives two high-pressure combined oil pumps (1) to operate through a large transmission ratio.

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