Marine engine dual fuel supply device

Abstract

The application discloses a marine engine dual-fuel supply device, which comprises a fuel injection mechanism, a mode switching mechanism and an injection timing adjusting mechanism; the fuel injection mechanism comprises a camshaft, a bearing disc, a plunger pump and a spring, the bearing disc is fixed at the lower end of the plunger of the plunger pump, is supported on the outer circumferential surface of the cam, and the spring is sleeved on the lower end of the plunger; the mode switching mechanism comprises a hydraulic cylinder, a connecting block, a supporting block, a driving connecting rod, a sliding block and a driving block, one end of the camshaft is supported in the connecting block of the piston rod end head, the supporting block is fixed on the upper side of the piston rod, one end of the driving connecting rod is hinged to the upper end of the supporting block, the other end is hinged to the sliding block, and the sliding block is arranged in the sliding groove of the driving block; the injection timing adjusting mechanism comprises an actuator, a rack and a gear, and the gear is fixed on the inner cylinder and on the side opposite to the driving block. The application can not only ensure the full combustion of diesel in the cylinder, but also greatly improve the atomization effect and flow supply capacity of methanol in the cylinder, and the methanol combustion efficiency is high.

Description

Technical Field

[0001] This invention relates to a fuel supply device for a marine engine, and more particularly to a fuel supply device capable of switching between diesel and methanol dual-fuel modes, belonging to the field of marine engine technology. Background Technology

[0002] In marine dual-fuel technology, methanol is often chosen as the second fuel besides diesel. As a clean fuel, methanol offers good fuel economy while significantly reducing SOx, NOx, and particulate matter emissions compared to diesel. Currently, the most commonly used dual-injection systems and manifold injection systems in dual-fuel engines are not only bulky and have poor applicability and are difficult to maintain, but also suffer from poor atomization and low combustion efficiency of methanol after it enters the cylinder, greatly affecting the normal operation of the engine. Summary of the Invention

[0003] The purpose of this invention is to provide a marine engine dual-fuel supply device that is simple in structure, low in cost, can achieve methanol-diesel dual-mode switching, and can meet the requirements of methanol-diesel dual-fuel injection.

[0004] This invention is achieved through the following technical solution:

[0005] A dual-fuel supply device for a marine engine includes a fuel injection mechanism, a mode switching mechanism, and a fuel injection timing adjustment mechanism. The fuel injection mechanism includes a camshaft, a bearing plate, a plunger pump, and a spring. The bearing plate is fixed to the lower end of the plunger pump plunger and movably supported on the outer circumferential surface of the cam on the camshaft. The spring is fitted onto the lower end of the plunger, and its upper and lower ends are positioned by the plunger pump and the bearing plate, respectively. A diesel delivery pipe and a methanol delivery pipe are fixed to the upper end of the plunger pump body. The plunger pump body includes an inner cylinder, a middle cylinder, and an outer cylinder. The inner and middle cylinders are rotatably fitted into the outer cylinder, and their bottoms are positioned by clamping gaskets. The mode switching mechanism is located on one side of the fuel injection mechanism. The mode switching mechanism includes... The system includes a hydraulic cylinder, a connecting block, a support block, a horizontally arranged drive connecting rod, a slider, and a drive block. The connecting block is fixed to the piston rod end of the hydraulic cylinder. One end of the camshaft is supported in the connecting block by several bearings and positioned by a pressure cap. The support block is vertically fixed to the upper side of the piston rod. One end of the drive connecting rod is hinged to the upper end of the support block, and the other end of the drive connecting rod is hinged to the slider. The slider is set in the groove of the drive block, and the drive block is fixed on one side of the middle cylinder. The fuel injection timing adjustment mechanism is set on the other side of the fuel injection mechanism. The fuel injection timing adjustment mechanism includes an actuator, a meshing rack and gear. The actuator is fixed to the outer end of the rack, and the gear is fixed to the inner cylinder on the side opposite to the drive block.

[0006] The objectives of this invention can also be further achieved through the following technical measures.

[0007] In the aforementioned dual-fuel supply device for marine engines, the cam on the camshaft is a variable-stroke cam with one end larger than the other, and the stroke of the small end of the variable-stroke cam is 0.3 to 0.5 times the stroke of the large end.

[0008] The aforementioned dual-fuel supply device for marine engines, wherein a drive block groove is provided on one side of the lower end of the outer cylinder, and gear grooves are provided on the lower ends of both the outer cylinder and the middle cylinder opposite to the drive block groove.

[0009] The aforementioned dual-fuel supply device for marine engines, wherein the upper end of the outer cylinder is provided with a diesel inlet, a methanol inlet, a diesel outlet and a methanol outlet on opposite sides; the upper end of the middle cylinder is provided with a first fuel inlet, a vertical first lubricating oil passage and a first fuel outlet on opposite sides; and the upper end of the inner cylinder is provided with a second fuel inlet, a horizontal second lubricating oil passage and a second fuel outlet on opposite sides.

[0010] In the aforementioned dual-fuel supply device for marine engines, the second fuel inlet and the second lubricating oil passage are both horizontal waist-shaped through holes, and the second fuel outlet is a horizontal waist-shaped groove, with a through hole in the middle of the horizontal waist-shaped groove.

[0011] This invention combines methanol-diesel dual-fuel modes into one, featuring a simple and compact structure, low cost, and convenient maintenance. The mode switching mechanism enables automatic switching between methanol and diesel dual-fuel injection modes, with injection via the fuel injection mechanism. This not only ensures complete combustion of diesel in the cylinder but also significantly improves the atomization effect and flow supply capacity of methanol within the cylinder, resulting in high methanol combustion efficiency. This effectively guarantees normal engine operation, reduces engine operating costs, and lowers pollutant emissions. Furthermore, the injection timing adjustment mechanism can adjust the injection quantity of diesel or methanol as needed, offering flexibility and convenience.

[0012] The advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments, which are given by way of example only with reference to the accompanying drawings. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the present invention;

[0014] Figure 2 This is a three-dimensional structural schematic diagram of the variable cam of the present invention;

[0015] Figure 3 This is a three-dimensional structural schematic diagram of the plunger pump of the present invention;

[0016] Figure 4 This is a schematic diagram of the diesel supply channel in diesel mode of the present invention;

[0017] Figure 5 This is a schematic diagram of the methanol supply channel in the methanol mode of the present invention;

[0018] Figure 6 This is a schematic diagram of the lubricating oil supply channel in the methanol mode of the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] like Figure 1 As shown, the present invention includes a fuel injection mechanism 1, a mode switching mechanism 2, and a fuel injection timing adjustment mechanism 3. The fuel injection mechanism 1 includes a camshaft 11, a bearing 12, a plunger pump 13, and a spring 14. The bearing 12 is fixed to the lower end of the plunger of the plunger pump 13 by a pin and is movably supported on the outer peripheral surface of the cam 15 on the camshaft 11. The bearing 12 can be axially displaced along the outer peripheral surface of the cam 15. Figure 2 As shown, since the calorific value of methanol is about half that of diesel, a greater amount of methanol injection is required in one stroke. Therefore, the cam 15 on the camshaft 11 is designed as a variable stroke cam with a larger stroke on the left and a smaller stroke on the right to meet the methanol injection requirements. The rightmost stroke of the variable stroke cam is 0.3 to 0.5 times the leftmost stroke. In this embodiment, the rightmost stroke of the variable stroke cam is 0.5 times the leftmost stroke. The spring 14 is fitted onto the lower end of the plunger. The upper and lower ends of the spring 14 are positioned by the plunger pump 13 and the bearing plate 13, respectively. The upper end of the plunger pump 13 is fixed with a diesel delivery pipe 16 and a methanol delivery pipe 17, respectively.

[0021] like Figure 3 As shown, the pump body of the plunger pump 13 includes an inner cylinder 131, a middle cylinder 132, and an outer cylinder 133. The inner cylinder 131 and the middle cylinder 132 are rotatably fitted inside the outer cylinder 133, and their bottoms are positioned by clamping gaskets 134. A drive block groove 135 is provided on one side of the lower end of the outer cylinder 133, and gear grooves 136 are provided on the lower ends of both the outer cylinder 133 and the middle cylinder 132 opposite to the drive block groove 135. The upper end of the outer cylinder 133 is provided with a diesel inlet 10, a methanol inlet 20, a diesel outlet 30 and a methanol outlet 40 on opposite sides. The upper end of the middle cylinder 132 is provided with a first fuel inlet 50, a vertical first lubricating oil passage 60 and a first fuel outlet 70 on opposite sides. The upper end of the inner cylinder 131 is provided with a second fuel inlet 80, a horizontal second lubricating oil passage 90 and a second fuel outlet 100 on opposite sides. The second fuel inlet 80 and the second lubricating oil passage 90 are both horizontal waist-shaped through holes, and the second fuel outlet 80 is a horizontal waist-shaped groove with a through hole in the middle.

[0022] like Figure 1As shown, the mode switching mechanism 2 is located on the right side of the fuel injection mechanism 1. The mode switching mechanism 2 includes a hydraulic cylinder 21, a connecting block 22, a support block 23, a horizontally arranged drive connecting rod 24, a slider 25, and a drive block 26. The connecting block 22 consists of two semicircles, which enclose the pressure cap 27 and are then fixed to the piston rod end of the hydraulic cylinder 21 by bolts. The right end of the camshaft 11 is supported in the connecting block 22 by two planar thrust bearings and positioned by the pressure cap 27. The support block 23 is vertically welded and fixed to the upper side of the piston rod. The right end of the drive connecting rod 24 is hinged to the upper end of the support block 23, and its left end is hinged to the slider 25. The slider 25 is located in the groove of the drive block 26, and the drive block 26 is welded and fixed to one side of the middle cylinder 132.

[0023] The fuel injection timing adjustment mechanism 3 is located on the other side of the fuel injection mechanism 1. The fuel injection timing adjustment mechanism 3 includes an actuator 31, a meshing rack 32 and a gear 33. The actuator 31 is fixed on the outer end of the rack 32, and the gear 33 is welded and fixed on the inner cylinder 131 on the side opposite to the drive block 26.

[0024] like Figure 1 and Figure 4 As shown, in diesel mode, the plunger pump 13 is located at the rightmost end of the cam 15, and the drive block 26 is located at the leftmost end of the drive block groove 135. At this time, diesel fuel enters the fuel chamber of the plunger pump 13 body through the diesel inlet 10, the first fuel inlet 50, and the second fuel inlet 80 in sequence. As the camshaft 11 rotates, the plunger 137 moves upward. When the top of the plunger 137 is higher than each inlet, the fuel injection stops, and the plunger 137 continues to move upward, entering the fuel injection process. When the pressure in the fuel chamber of the plunger pump 13 body reaches the preset pressure of the fuel injection valve, the fuel injection valve starts to inject fuel. At this time, the plunger 137 reaches the top dead center, the camshaft 11 continues to rotate, and the plunger 137 moves downward. When the return oil profile 138 on the plunger 137 connects with the second fuel outlet 100, the return oil pressure is released, and the diesel fuel enters the fuel outlet pipe through the second fuel outlet 100, the first fuel outlet 70, and the diesel outlet 30 in sequence. At this time, one stroke ends.

[0025] When it is necessary to switch to methanol mode, such as Figure 1 As described above, adjusting the pressure difference within the hydraulic cylinder 21 causes the piston rod to retract to the right. The piston rod, via the support block 23, drives the drive connecting rod 24 to move to the right, causing the drive block 26 to rotate counterclockwise along the drive block groove 135. The drive block 26 then drives the middle cylinder 132 to rotate counterclockwise. Simultaneously, the piston rod drives the camshaft 11 to move to the right, and the camshaft 11 rotates while moving. When the drive block 26 rotates to the rightmost side of the drive groove 135, as... Figure 5As shown, at this time, methanol inlet 20, first fuel inlet 50 and second fuel inlet 80 are connected, methanol outlet 40, first fuel outlet 70 and second fuel outlet 100 are connected, and plunger pump 13 is located at the leftmost end of cam 15. The mode switching is completed.

[0026] The methanol injection process is the same as the diesel injection process. The difference lies in that, in diesel mode, the plunger pump 13 relies on diesel fuel for self-lubrication, while in methanol mode, because the kinematic viscosity of methanol is much lower than that of diesel fuel, a diesel fuel lubrication passage is provided. Figure 6 As shown, in methanol mode, diesel inlet 10, first lubrication oil passage 60, and second lubrication oil passage 90 are connected. Diesel flows downward from diesel inlet 10 through first lubrication oil passage 60, enters second lubrication oil passage 90, and then flows directly into the oil reservoir at the upper end of plunger 137, filling the reservoir to lubricate the plunger for one stroke. The second lubrication oil passage 90 is located on the lower side of the top of plunger 137 to prevent methanol and diesel fuel from entering the pump body fuel chamber of plunger pump 13 simultaneously.

[0027] During fuel injection timing adjustment, the injection advance angle can be adjusted by adding a VIT adjustment device to the left end of the camshaft 11, and the fuel injection quantity is adjusted by rotating the inner cylinder 131. The actuator 31 issues a command based on the real-time engine status and fuel demand, driving the rack 32 to move. The gear 33 meshing with the rack 32 drives the inner cylinder 131 to rotate, and the second fuel outlet 100 rotates accordingly. At this time, the relative position of the second fuel outlet 100 and the plunger return oil profile 138 changes, and the return oil timing also changes, thereby realizing the adjustment of the fuel injection quantity.

[0028] In addition to the above embodiments, the present invention may have other implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A dual-fuel supply device for a marine engine, characterized in that: The system includes a fuel injection mechanism, a mode switching mechanism, and a fuel injection timing adjustment mechanism. The fuel injection mechanism comprises a camshaft, a bearing plate, a plunger pump, and a spring. The bearing plate is fixed to the lower end of the plunger pump plunger and movably supported on the outer circumferential surface of a cam on the camshaft. The cam on the camshaft is a variable-stroke cam with one end larger than the other, the stroke of the smaller end of the variable-stroke cam being 0.3 to 0.5 times the stroke of the larger end. The spring is fitted onto the lower end of the plunger, with its upper and lower ends positioned by the plunger pump and the bearing plate, respectively. A diesel delivery pipe and a methanol delivery pipe are fixed to the upper end of the plunger pump body, respectively. The plunger pump body includes an inner cylinder, a middle cylinder, and an outer cylinder. The inner and middle cylinders are rotatably fitted into the outer cylinder, and their bottoms are positioned by clamping shims. A drive block groove is provided on one side of the lower end of the outer cylinder, and the lower ends of the outer and middle cylinders are connected to the drive block groove. Gear slots are provided on both opposite sides; the mode switching mechanism is located on one side of the fuel injection mechanism. The mode switching mechanism includes a hydraulic cylinder, a connecting block, a support block, a horizontally arranged drive rod, a slider, and a drive block. The connecting block is fixed to the piston rod end of the hydraulic cylinder. One end of the camshaft is supported in the connecting block by several bearings and positioned by a pressure cap. The support block is vertically fixed to the upper side of the piston rod. One end of the drive rod is hinged to the upper end of the support block, and the other end of the drive rod is hinged to the slider. The slider is located in the groove of the drive block, and the drive block is fixed on one side of the middle cylinder. The fuel injection timing adjustment mechanism is located on the other side of the fuel injection mechanism. The fuel injection timing adjustment mechanism includes an actuator, a meshing rack and gear. The actuator is fixed to the outer end of the rack, and the gear is fixed to the inner cylinder on the side opposite to the drive block.

2. The dual-fuel supply device for marine engines as described in claim 1, characterized in that: The upper end of the outer cylinder is provided with a diesel inlet, a methanol inlet, a diesel outlet, and a methanol outlet on opposite sides; the upper end of the middle cylinder is provided with a first fuel inlet, a vertical first lubricating oil passage, and a first fuel outlet on opposite sides; the upper end of the inner cylinder is provided with a second fuel inlet, a horizontal second lubricating oil passage, and a second fuel outlet on opposite sides.

3. The dual-fuel supply device for marine engines as described in claim 2, characterized in that: The second fuel inlet and the second lubricating oil passage are both horizontal waist-shaped through holes, and the second fuel outlet is a horizontal waist-shaped groove with a through hole in the middle of the horizontal waist-shaped groove.

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