Micro-jet ignition dual-fuel gas engine fuel supply system based on electronic unit pump

Abstract

The utility model discloses a micro-jet ignition dual-fuel gas engine fuel oil supply system based on an electronic unit pump, a plunger stroke adjusting mechanism is arranged between an oil pumping cam and the unit pump, the plunger stroke adjusting mechanism comprises a sliding sleeve, a main plunger, a piston, a reset spring and the like, the main plunger is in transmission connection with a swing mechanism, and the piston is in transmission connection with the swing mechanism. The swing mechanism is driven by a linkage plunger and barrel assembly and reverses and resets through a return spring, the linkage plunger and barrel assembly is selectively communicated with an engine oil way or an oil pan of an engine through an electromagnetic reversing valve, a plunger boss is arranged at one end of the main plunger, a piston boss is arranged at one end of the piston, and the piston boss is arranged at the other end of the piston. The sliding sleeve oil inlet is communicated with an engine oil way through a one-way valve, and the sliding sleeve oil outlet is connected with a drainage control oil way. The requirement for responsiveness of the monoblock pump electromagnetic valve is obviously lowered, the fuel oil supply requirement of the micro-jet gas engine can be met, and the engine can be restored to the full-power diesel engine state to operate after gas fuel is used up.

Description

Technical Field

[0001] The utility model relates to the technical field of engine fuel supply systems, in particular to a fuel supply system for a micro-injection ignition dual-fuel gas engine based on an electronically controlled unit pump. Background Technique

[0002] For a micro-injection ignition dual-fuel gas engine, the fuel supply system is divided into a fuel supply system and a gas supply system, which means that a small amount of diesel (1% - 5% of the full-load fuel quantity) is used as the ignition fuel and is injected into the cylinder for compression ignition to ignite the main gas fuel for work. Compared with a spark-ignition gas engine, the micro-diesel ignition system has a large ignition energy and good penetration, which can significantly improve the power performance and economy of the engine; when the gas fuel is used up, the engine can burn diesel fuel alone and become a diesel engine to output work.

[0003] When the engine is operating in the state of a micro-injection ignition gas engine, since the fuel is the ignition energy of the gas fuel, the amount of fuel injection per cycle determines the size of the ignition energy, directly determines the combustion characteristics of the gas fuel, and thus affects the performance of the engine. Therefore, a very high precision requirement is imposed on the supply control of the small amount of fuel injected. The commonly used fuel supply system is a high-pressure common-rail fuel supply system. The fuel pressure in the rail pipe is stable, and the fuel injection quantity is controlled by the opening moment of the solenoid valve. The control precision is high, which can meet the fuel supply requirements of micro-injection ignition.

[0004] The high-pressure common-rail fuel supply system has been widely used in diesel engines with a power of less than 500KW. For large engines with a power greater than 1000KW, due to the changes in process and structure of the matching high-pressure common-rail fuel supply system, the cost has soared significantly, and the price has increased by more than ten times, which has restricted its application. Therefore, most large diesel engines still use an electronically controlled unit pump fuel supply system.

[0005] The traditional electronically controlled unit pump fuel supply system usually includes a cam, a fuel pumping system, a solenoid valve, a high-pressure oil pipe, and an injector. The cam drives the roller to drive the plunger to reciprocate, boosting the diesel to the high-pressure chamber. When the electromagnet is not energized, the sealing cone surface does not fit, and the diesel in the high-pressure chamber leaks through the gap of the sealing cone surface. The diesel in the high-pressure oil pipe does not build up high pressure and cannot drive the injector to open, and the injector does not inject fuel. When the solenoid valve is energized, the sealing cone surface fits, the diesel pressure in the high-pressure chamber rises, enters the injector through the high-pressure oil pipe. After the diesel pressure reaches the opening pressure of the injector, the injector opens to inject diesel into the cylinder. When the solenoid valve is de-energized again, the sealing cone surface opens to release pressure under the action of the spring force, and the injector stops injecting fuel.

[0006] During the fuel pumping process of the cam, by controlling the duration from the closing to the opening moment of the solenoid valve, the fuel supply amount per cycle of the unit pump can be controlled. Under certain rotational speed conditions, the duration from the closing to the opening moment of the solenoid valve corresponds to the cam angle. If this system meets the requirements of a micro-injection engine and the fuel injection amount needs to reach 1% - 5% of the full-load fuel amount, then the corresponding cam angle during micro-injection operation must be quite small. For example, if the duration from the closing to the opening moment of the solenoid valve corresponding to a certain engine rotational speed is 2 milliseconds, then the corresponding time requirement during micro-injection is less than 0.2 milliseconds, which far exceeds the response time requirement of the solenoid valve.

[0007] Some micro-injection engines of certain manufacturers adopt the following solution: matching a small high-pressure common rail fuel system. For example, for a 1000KW engine, the matched high-pressure common rail system can only meet the diesel supply demand of 300KW. This solution solves the problems of control accuracy and cost of the fuel supply system (the cost of the small high-pressure common rail system is low), but when the gaseous fuel is used up, it cannot resume operation in the full-power diesel engine state (it can only resume to the 300KW diesel engine state), which limits its application. Summary of the Invention

[0008] In view of this, the present invention provides a fuel supply system for a micro-injection ignition dual-fuel gas engine based on an electronically controlled unit pump to meet the fuel supply demand of the micro-injection ignition dual-fuel gas engine and enable the engine to resume operation in the full-power diesel engine state.

[0009] To solve the above technical problems, the technical solution adopted by the present invention is:

[0010] A fuel supply system for a micro-injection ignition dual-fuel gas engine based on an electronically controlled unit pump, comprising: an electronically controlled unit pump, the electronically controlled unit pump including a pump body, a valve body and a push rod, the valve body being fixedly installed in the pump body, the push rod being slidably installed in the pump body, a main spring being clamped between the valve body and the push rod, the push rod being provided with a unit pump roller extending out of the pump body; a unit pump plunger slidably installed in the valve body and abutted against the push rod, the valve body being provided with a main oil passage and a drain passage, the main oil passage communicating with the drain passage, the valve body being provided with a unit pump solenoid valve for controlling the on-off of the drain passage; a pump oil cam, the pump oil cam being installed on a camshaft; a plunger stroke adjusting mechanism being provided between the pump oil cam and the unit pump roller, the plunger stroke adjusting mechanism including a sliding sleeve, a main plunger, a piston and a return spring, the sliding sleeve being fixed relative to the engine, the main plunger and the piston being respectively in sliding and sealing fit with the sliding sleeve, the inner cavity between the main plunger and the piston being called a sliding sleeve cavity, the return spring being clamped between the main plunger and the piston, the piston abutting against the pump oil cam, the main plunger abutting against the unit pump roller; the main plunger being drivingly connected with a rotary mechanism; the sliding sleeve being provided with a positioning pin, the piston being provided with an axially extending guide groove, the positioning pin extending into the guide groove to limit the rotation of the piston; the sliding sleeve being provided with a sliding sleeve inlet hole and a sliding sleeve outlet hole respectively communicating with the sliding sleeve cavity, the sliding sleeve inlet hole being communicated with an engine oil oil circuit through a one-way valve, the sliding sleeve outlet hole being connected with a drain control oil circuit; the rotary mechanism being driven by a linkage plunger pair and reversely reset by a return spring, the linkage plunger pair being selectively communicated with the engine oil oil circuit or an oil sump through an electromagnetic reversing valve; one end of the main plunger being provided with a plunger boss, one end of the piston being provided with a piston boss; when the electromagnetic reversing valve is energized, the engine oil oil circuit is connected to the linkage plunger pair, overcoming the spring force of the return spring, pushing the rotary mechanism to move, so that the plunger boss is circumferentially displaced relative to the piston boss, the system being in a non-rigid connection state, a part of the hydraulic oil in the sliding sleeve cavity flowing out through the drain control oil circuit, so that the stroke of the unit pump plunger is less than the lift of the pump oil cam; when the electromagnetic reversing valve is de-energized, the electromagnetic reversing valve is connected to the oil sump, and under the action of the return spring, pushing the rotary mechanism to move in the reverse direction, so that the end faces of the piston boss and the plunger boss are abutted and aligned, the stroke of the unit pump plunger being controlled by the pump oil cam, the system being in a rigid connection state.

[0011] Among them, a throttling device is provided in the bleed-off control oil circuit; or a relief valve is provided in the bleed-off control oil circuit; or a relief valve and a throttling device are provided in the bleed-off control oil circuit, and the throttling device and the relief valve are arranged in series; or a throttling device and a switching solenoid valve are provided in the bleed-off control oil circuit, and the throttling device and the switching solenoid valve are arranged in series.

[0012] Among them, the linkage plunger pair includes a linkage plunger and a linkage plunger sleeve, the rotary mechanism includes a control gear and a rack that mesh with each other, the control gear is connected to the main plunger in a torque transmission manner, the return spring is a compression spring, and under the action of the return spring, the rack abuts against the linkage plunger; the rack is a multi-cylinder rack, and the multi-cylinder rack meshes with the control gears of a plurality of the main plungers at the same time.

[0013] Among them, the linkage plunger pair includes a linkage plunger and a linkage plunger sleeve, the rotary mechanism includes a control disk and a hinge pin, the control disk is connected to the main plunger in a torque transmission manner, the hinge pin is eccentrically fixed on the control disk, a transverse opening groove is formed in the linkage plunger, and the hinge pin is movably arranged in the transverse opening groove; the return spring is a tension spring connected to the linkage plunger, the tension spring is arranged in the linkage plunger sleeve, or the return spring is a compression spring, the compression spring abuts against the outside of the linkage plunger, or the return spring is a torsion spring, and the torsion spring is connected between the hinge pin and the control disk.

[0014] Among them, the linkage plunger pair includes a linkage plunger and a linkage plunger sleeve, the rotary mechanism includes a control disk and a hinge pin, the control disk is connected to the main plunger in a torque transmission manner, the hinge pin is fixed on the linkage plunger, a transverse opening groove is formed in the control disk, and the hinge pin is movably arranged in the transverse opening groove; the return spring is a tension spring connected to the linkage plunger, the tension spring is arranged in the linkage plunger sleeve, or the return spring is a compression spring, the compression spring abuts against the outside of the linkage plunger, or the return spring is a torsion spring, and the torsion spring is connected between the hinge pin and the control disk.

[0015] After adopting the above technical solutions, the technical effects achieved by the present utility model are:

[0016] The utility model provides a plunger stroke adjusting mechanism between an electronically controlled unit pump and a fuel injection cam. The plunger stroke adjusting mechanism includes a sliding sleeve, a main plunger, a piston, a return spring, etc. The main plunger is drivingly connected with a rotary mechanism. The rotary mechanism is driven by a linkage plunger pair and reversely resets through a return spring. The linkage plunger pair can be selectively communicated with the engine oil circuit or the oil pan through an electromagnetic reversing valve. One end of the main plunger is provided with a plunger boss, and one end of the piston is provided with a piston boss. The oil inlet hole of the sliding sleeve is communicated with the engine oil circuit through a check valve, and the oil outlet hole of the sliding sleeve is connected with a bleed control oil circuit. When the engine operates in the diesel state, the electromagnetic reversing valve is de-energized, and the linkage plunger pair is communicated with the oil pan. Under the action of the return spring, the rotary mechanism rotates, driving the main plunger to rotate. The end faces of the plunger boss and the piston boss are abutted and aligned, and the system is in a rigid connection state. The fuel injection cam drives the piston, the main plunger, and the unit pump plunger to move, and the plunger stroke of the unit pump plunger is equal to the height corresponding to the cam profile of the fuel injection cam. When the engine operates in the micro-injection state, the electromagnetic reversing valve is energized, and the engine oil circuit is connected to the linkage plunger pair, overcoming the spring force of the return spring and pushing the rotary mechanism to move, causing the plunger boss to be circumferentially misaligned relative to the piston boss. The system is in a non-rigid connection state, and the main plunger and the piston can move relative to each other. When the fuel injection cam drives the piston to move, part of the hydraulic oil in the sliding sleeve cavity flows out of the sliding sleeve cavity through the bleed control oil circuit, making the movement stroke of the main plunger smaller than that of the piston. Furthermore, the stroke of the unit pump plunger is reduced, greatly increasing the injection timing that meets the micro-injection requirements and significantly reducing the responsiveness requirements for the unit pump solenoid valve, thus meeting the fuel supply requirements of the micro-injection gas engine. The electronically controlled unit pump has a lower cost compared to the high-pressure common rail fuel system and can achieve full-power matching. When the gas fuel is used up, the engine can be restored to operate in the full-power diesel state.

[0017] In the utility model, the bleed control oil circuit can have various structural forms, either adopting a throttling device, or an overflow valve, or arranging the throttling device and the overflow valve in series, or arranging the throttling device and a switch solenoid valve in series. When the throttling device and the overflow valve are arranged in series, the throttling device controls the stroke of the plunger by controlling the flow rate, and the overflow valve controls the stroke of the plunger by controlling the relief pressure. The combination of the two can improve the control accuracy. When the throttling device and the electromagnetic switch valve are arranged in series, it can prevent the engine oil from leaking through the throttle orifice of the throttling device when the engine operates in the diesel state. Description of the Drawings

[0018] Figure 1 is a longitudinal sectional view of Embodiment 1 of the fuel supply system of a micro-injection ignition dual-fuel gas engine based on an electronically controlled unit pump of the utility model;

[0019] Figure 2 is Figure 1Schematic structural diagram of the control part of the central slewing mechanism;

[0020] Figure 3 is Figure 1 Schematic three-dimensional structure diagram of the main plunger in the middle;

[0021] Figure 4 is Figure 1 Schematic three-dimensional structure diagram of the piston in the middle;

[0022] Figure 5 is Figure 1 Schematic diagram of the state when the plunger boss in the middle abuts and aligns with the end face of the piston boss;

[0023] Figure 6 is Figure 1 Schematic diagram of the state when the plunger boss in the middle is circumferentially misaligned with the piston boss;

[0024] Figure 7 is Figure 5 Diagram of the change in the plunger stroke of the unit pump when the system shown is in a rigid connection state;

[0025] Figure 8 is Figure 6 Diagram of the change in the plunger stroke of the unit pump when the system shown is in a non-rigid connection state;

[0026] Figure 9 Schematic structural diagram of the control part of the slewing mechanism in Embodiment 2 of the fuel supply system of the micro-injection ignition dual-fuel gas engine based on the electronically controlled unit pump of the present utility model;

[0027] Figure 10 Schematic structural diagram of the control part of the slewing mechanism in Embodiment 3 of the fuel supply system of the micro-injection ignition dual-fuel gas engine based on the electronically controlled unit pump of the present utility model;

[0028] Figure 11 Schematic structural diagram of the control part of the slewing mechanism in Embodiment 4 of the fuel supply system of the micro-injection ignition dual-fuel gas engine based on the electronically controlled unit pump of the present utility model;

[0029] Figure 12 Longitudinal sectional view of Embodiment 5 of the fuel supply system of the micro-injection ignition dual-fuel gas engine based on the electronically controlled unit pump of the present utility model;

[0030] Figure 13 Longitudinal sectional view of Embodiment 6 of the fuel supply system of the micro-injection ignition dual-fuel gas engine based on the electronically controlled unit pump of the present utility model;

[0031] Figure 14 Longitudinal sectional view of Embodiment 7 of the fuel supply system of the micro-injection ignition dual-fuel gas engine based on the electronically controlled unit pump of the present utility model;

[0032] In the figure, 10A is the fuel injection cam; 10C is the camshaft; 20 is the electronic control unit injector pump; 21 is the pump body; 211 is the inlet hole of the unit injector pump; 22 is the push rod; 23 is the roller of the unit injector pump; 24 is the main spring; 25 is the plunger of the unit injector pump; 26 is the valve body; 261 is the inlet passage; 262 is the high-pressure chamber; 263 is the main oil passage; 27 is the solenoid valve of the unit injector pump;

[0033] 30 is the plunger stroke adjustment mechanism; 31A is the wear-resistant gasket; 31B is the thrust bearing; 32 is the main plunger; 32A is the control gear; 32B is the plunger boss; 32C is the control disk; 33 is the sliding sleeve; 33A is the inlet hole of the sliding sleeve; 33B is the outlet hole of the sliding sleeve; 34 is the return spring; 35 is the piston; 35A is the piston boss; 35B is the guide groove; 36 is the positioning pin; 37 is the piston roller; 38 is the one-way valve; 39A is the throttling device; 39B is the overflow valve; 39C is the electromagnetic switch valve; 50 is the linkage plunger sleeve; 51 is the linkage plunger; 52 is the rack; 53 is the return spring; 54 is the articulated pin shaft; 55 is the tension spring; 56 is the torsion spring; 57 is the multi-cylinder rack; 58 is the electromagnetic reversing valve; 59 is the oil pan; 72 is the signal disk; 71 is the phase sensor; Q is the sliding sleeve chamber. Detailed implementation mode

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] Embodiment 1

[0036] As Figure 1 shown, a fuel supply system for a micro-injection ignition dual-fuel gas engine based on an electronic control unit injector pump mainly includes an electronic control unit injector pump 20, a fuel injection cam 10A, and a plunger stroke adjustment mechanism 30. The fuel injection cam 10A is installed on the camshaft 10C, the signal disk 72 is fixedly connected to the camshaft 10C, the phase sensor 71 is electrically connected to the electronic control unit, the electronic control unit detects the circumferential position of the camshaft 10C through the signal disk 72 and the phase sensor 71, and the plunger stroke adjustment mechanism 30 is used to adjust the stroke of the plunger of the unit injector pump, which will be described in detail below.

[0037] The electronic control unit injector pump 20 includes a pump body 21, a valve body 26, and a push rod 22. The valve body 26 is fixedly installed in the pump body 21, the push rod 22 is slidably installed in the pump body 21, a main spring 24 is clamped between the valve body 26 and the push rod 22, and a roller of the unit injector pump 23 extending out of the pump body 21 is installed on the push rod 22.

[0038] The pump body 21 is provided with a unit pump inlet hole 211, and the valve body 26 is provided with an oil inlet passage 261, a main oil passage 263, a high-pressure chamber 262 and a unit pump outlet hole. The unit pump inlet hole 211 communicates with the oil inlet passage 261. One end of the main oil passage 263 communicates with the unit pump outlet hole, and the other end communicates with the high-pressure chamber 262. The unit pump outlet hole is connected to a high-pressure oil pipe, and the high-pressure oil pipe is connected to an injector (not shown in the figure). A unit pump plunger 25 that abuts against the push rod 22 is slidably installed in the valve body 26. When the unit pump plunger 25 reciprocates, the fuel from the unit pump inlet hole 211 is pressurized to the high-pressure chamber 262 and is ejected from the injector through the high-pressure oil pipe via the main oil passage 263.

[0039] The valve body 26 is provided with a bleed passage communicating with the main oil passage 263, and a unit pump solenoid valve 27 for controlling the on / off of the bleed passage is also installed on the valve body 26.

[0040] Next, the plunger stroke adjustment mechanism 30 will be introduced in detail.

[0041] As Figure 1 and Figure 2 As shown together, the sliding sleeve 33 is fixed relative to the engine. The main plunger 32 and the piston 35 are respectively slidably and sealingly connected to the sliding sleeve 33. The main plunger 32 axially abuts against the unit pump roller 23, and the piston 35 is equipped with a piston roller 37, and the piston roller 37 abuts against the fuel pump cam 10A. Inside the sliding sleeve 33, the space between the main plunger 32 and the piston 35 is the sliding sleeve chamber Q, and the return spring 34 is clamped between the main plunger 32 and the piston 35.

[0042] The sliding sleeve 33 is provided with a sliding sleeve inlet hole 33A and a sliding sleeve outlet hole 33B that respectively communicate with the sliding sleeve chamber Q. The sliding sleeve inlet hole 33A is communicated with the engine oil oil circuit through a one-way valve 38, and the sliding sleeve outlet hole 33B is connected to a bleed control oil circuit. In this embodiment, a throttling structure 39A is provided in the bleed control oil circuit, and a part of the hydraulic oil in the sliding sleeve chamber Q flows out through the throttling device 39A. The throttling structure 39A can be a throttling hole structure, a throttle valve or other devices with a throttling effect.

[0043] As Figure 2As shown, the main plunger 32 is drivingly connected to a slewing mechanism. The slewing mechanism is driven by a linkage plunger pair and reversely reset by a return spring 53. The linkage plunger pair can be selectively communicated with the engine oil circuit or the oil pan 59 through an electromagnetic reversing valve 58 (preferably a two-position three-way electromagnetic reversing valve). The linkage plunger pair includes a linkage plunger 51 and a linkage plunger sleeve 50. The slewing mechanism is a rack and pinion mechanism. The rack and pinion mechanism includes a control gear 32A and a rack 52 that mesh with each other. The control gear 32A is connected to the main plunger 32 in a torque-transmitting manner. There are two ways to connect the control gear 32A to the main plunger 32. One is a fixed connection, and the other is that the control gear 32A can slide axially relative to the main plunger 32 but cannot rotate relative to it, such as a key connection. No matter which connection method is adopted, it must be able to transmit torque. The return spring 53 is a compression spring. Under the action of the return spring 53, the rack 52 abuts against the linkage plunger 51. In this embodiment, a six-cylinder four-stroke engine is taken as an example. One rack and pinion mechanism corresponds to one linkage plunger pair, and the control gear 32A of each main plunger 32 can be individually and flexibly controlled.

[0044] As Figure 1 and Figure 4 shown, the sliding sleeve 33 is provided with a positioning pin 36, and the piston 35 is provided with an axially extending guide groove 35B. The positioning pin 36 extends into the guide groove 35B to limit the rotation of the piston 35. One end of the piston 35 is provided with two piston bosses 35A, and the two piston bosses 35A are symmetrically arranged with respect to the center of the piston 35.

[0045] As Figure 3 shown, one end of the main plunger 32 is provided with two plunger bosses 32B, and the two plunger bosses 32B are symmetrically arranged with respect to the center of the main plunger 32. The plunger bosses 32B correspond to the piston bosses 35A one by one.

[0046] As Figure 6 shown, when the electromagnetic reversing valve 58 is energized, the engine oil circuit is connected to the linkage plunger pair, overcoming the spring force of the return spring 53, pushing the slewing mechanism to move, causing the plunger boss 32B to be circumferentially misaligned relative to the piston boss 35A, and the system is in a non-rigid connection state.

[0047] As Figure 5 shown, when the electromagnetic reversing valve 58 is de-energized, the linkage plunger pair is communicated with the oil pan 59. Under the action of the return spring 53, the slewing mechanism is pushed to move in the reverse direction, causing the end faces of the piston boss 35A and the plunger boss 32B to abut and align. The stroke of the unit pump plunger 25 is controlled by the camshaft 10A, and the system is in a rigid connection state.

[0048] In this embodiment, the unit pump solenoid valve 27 is a normally open electromagnetic switch valve.

[0049] The working principle of the present utility model is as follows:

[0050] When the engine operates in the diesel engine state, the electromagnetic reversing valve 58 is de-energized, and the linkage plunger pair is communicated with the oil sump 59. Under the action of the return spring 53, the rack 52 drives the control gear 32A to move, and the control gear 32A drives the main plunger 32 to rotate. The plunger boss 32B abuts and aligns with the end face of the piston boss 35A, and the system is in a rigid connection state. As Figure 5 shown, the fuel injection cam 10A drives the piston 35, the main plunger 32, and the unit pump plunger 25 to move. The plunger stroke of the unit pump plunger 25 is equal to the height corresponding to the cam profile of the fuel injection cam 10A. As Figure 7 shown.

[0051] When the engine operates in the micro-injection state, the electromagnetic reversing valve 58 is energized, and the engine oil oil circuit is connected to the linkage plunger pair. Overcoming the spring force of the return spring 53, it pushes the rotary mechanism to move, causing the plunger boss 32B to be circumferentially misaligned relative to the piston boss 35A, and the system is in a non-rigid connection state. The main plunger 32 and the piston 35 can move relative to each other. As Figure 6 shown. When the fuel injection cam 10A drives the piston 35 to move, as Figure 1 shown, part of the hydraulic oil in the sliding sleeve cavity Q flows out of the sliding sleeve cavity Q through the throttling device 39A, so that the movement stroke of the main plunger 32 is less than that of the piston 35, and further the stroke of the unit pump plunger 25 is reduced. Figure 8 is the stroke diagram of the unit pump plunger. The dotted part is the stroke diagram of the plunger of the conventional electronically controlled unit pump, and the solid line part is the stroke diagram of the unit pump plunger when the system is in a non-rigid connection state. By adjusting the size of the throttling hole of the throttling device 39A, the stroke of the plunger can be changed. As can be seen from Figure 8 it, after the stroke of the unit pump plunger 25 is reduced, the fuel injection time that meets the micro-injection is greatly increased, and the response requirement for the unit pump solenoid valve 27 is significantly reduced, which can meet the fuel supply requirements of the micro-injection gas engine.

[0052] In this embodiment, a thrust bearing 31B is provided on the end face of the control gear 32A, and a wear-resistant gasket 31A is provided between the thrust bearing 32B and the unit pump roller 23 to reduce wear, and the distance between the piston boss 35A and the plunger boss 32B can be adjusted by the thickness of the wear-resistant sheet 31A.

[0053] Embodiment 2

[0054] As Figure 9As shown in the figure, the structure of this embodiment is basically the same as that of Embodiment 1. The difference lies in that the rack for driving and controlling the reciprocating rotation of the driving control gear 32A adopts a multi-cylinder rack 57. The multi-cylinder rack 57 meshes with the control gears 32A of a plurality of main plungers 32 at the same time. As long as the multi-cylinder rack 57 is driven, the six main plungers 32 can be controlled to reciprocate and rotate simultaneously. The structure is more compact. All cylinders jointly control the conversion of the diesel state / micro-injection state, which is applicable to engines with relatively small power.

[0055] Embodiment 3

[0056] As Figure 10 shown in the figure, the structure of this embodiment is basically the same as that of Embodiment 1. The difference lies in that the swing mechanism includes a control disk 32C and a hinge pin 54. The control disk 32C is connected to the main plunger 32 in a manner of transmitting torque. The hinge pin 54 is eccentrically fixed on the control disk 32C. A transverse opening groove is formed on the linkage plunger 51, and the hinge pin 54 is movably arranged in the transverse opening groove; a tension spring 55 is connected to the linkage plunger 51 to form a return spring, and the tension spring 55 is arranged in the linkage plunger sleeve 50. Of course, the return spring can also be set as a compression spring that abuts against the outside of the linkage plunger 51, or a torsion spring that is connected between the hinge pin 54 and the control disk 32C.

[0057] Embodiment 4

[0058] As Figure 11 shown in the figure, the structure of this embodiment is basically the same as that of Embodiment 1. The difference lies in that the swing mechanism includes a control disk 32C and a hinge pin 54. The control disk 32C is connected to the main plunger 32 in a manner of transmitting torque. The hinge pin 54 is fixed on the linkage plunger 51, and a transverse opening groove is formed on the control disk 32C. The hinge pin 54 is movably arranged in the transverse opening groove; a torsion spring 56 is arranged between the hinge pin 54 and the control disk 32C, and the torsion spring 56 forms a return spring. Of course, the return spring can also be set as a compression spring that abuts against the outside of the linkage plunger 51, or a tension spring as in Embodiment 3.

[0059] Embodiment 5

[0060] As Figure 12 shown in the figure, the structure of this embodiment is basically the same as that of Embodiment 1. The difference lies in that the structure of the bleed control oil circuit connected to the bleed hole 33B of the sliding sleeve is different. In this embodiment, a relief valve 39B is arranged in the bleed control oil circuit. The bleed of the hydraulic oil in the sliding sleeve cavity Q can be controlled through the relief valve 39B. By adjusting the size of the pressure regulating spring of the relief valve 39B, the effect of changing the stroke of the unit pump plunger 25 can also be achieved.

[0061] Embodiment 6

[0062] As Figure 13As shown, the structure of this embodiment is basically the same as that of Embodiment 1, except that the structure of the bleed-off control oil circuit connected to the sliding sleeve oil outlet 33B is different. In this embodiment, not only a throttling device 39A is provided in the bleed-off control oil circuit, but also a relief valve 39B is provided. The throttling device 39A and the relief valve 39B are connected in series. Since the throttling device 39A controls the stroke of the flow control plunger by controlling the flow rate, and the relief valve 39B controls the stroke of the plunger by controlling the relief pressure, the combination of the two can improve the control accuracy.

[0063] Embodiment 7

[0064] As Figure 14 shown, the structure of this embodiment is basically the same as that of Embodiment 1, except that the structure of the bleed-off control oil circuit connected to the sliding sleeve oil outlet 33B is different. In this embodiment, not only a throttling device 39A is provided in the bleed-off control oil circuit, but also an electromagnetic solenoid valve 39C is provided in parallel to prevent engine oil from bleeding off through the throttle orifice of the throttling device 39A when the engine is operating in diesel mode.

[0065] The present utility model is not limited to the above embodiments. All improvements made based on the concept, principle, structure, and method of the present utility model will fall within the protection scope of the present utility model.

Claims

1. A fuel supply system for a micro-injection ignition dual-fuel gas engine based on an electronically controlled unit pump, comprising: An electrically controlled monomer pump, the electrically controlled monomer pump comprising a pump body, a valve body and a push rod, the valve body being fixedly mounted in the pump body, the push rod being slidably mounted in the pump body, a main spring being clamped between the valve body and the push rod, the push rod being mounted with a monomer pump roller extending out of the pump body; a monomer pump plunger being slidably mounted in the valve body against the push rod, the valve body being provided with a main oil passage and a leakage passage, the main oil passage being communicated with the leakage passage, and a monomer pump solenoid valve for controlling the on-off of the leakage passage being mounted on the valve body; The oil pumping cam is installed on the camshaft; the characteristics are: A plunger stroke adjustment mechanism is arranged between the oil pump cam and the monomer pump roller, and the plunger stroke adjustment mechanism comprises a sleeve, a main plunger, a piston and a return spring, the sleeve is fixed relative to the engine, the main plunger and the piston are respectively matched with the sleeve for sliding sealing, the inner cavity between the main plunger and the piston is called the sleeve cavity, the return spring is clamped between the main plunger and the piston, the piston is pressed against the oil pump cam, and the main plunger is pressed against the monomer pump roller; the main plunger is transmission-connected with a rotary mechanism; the sleeve is provided with a locating pin, and the piston is provided with a guide groove extending in the axial direction, and the locating pin extends into the guide groove to limit the rotation of the piston; the sleeve is provided with a sleeve oil inlet hole and a sleeve oil outlet hole respectively connected with the sleeve cavity, the sleeve oil inlet hole is connected with the engine oil circuit through a one-way valve, and the sleeve oil outlet hole is connected with a leakage control oil circuit; The rotary mechanism is driven by the linkage plunger pair and reversely reset by the return spring. The linkage plunger pair can be selectively connected to the engine oil circuit or the oil pan through the electromagnetic reversing valve; a plunger boss is provided at one end of the main plunger, and a piston boss is provided at one end of the piston; when the electromagnetic reversing valve is energized, the engine oil circuit is connected to the linkage plunger pair, overcoming the spring force of the return spring, pushing the rotary mechanism to move, so that the plunger boss is circumferentially displaced relative to the piston boss, and the system is in a non-rigid connection state, and part of the hydraulic oil in the sliding sleeve cavity flows out through the leakage control oil circuit, so that the stroke of the single pump plunger is less than the lift of the pump oil cam; when the electromagnetic reversing valve is de-energized, the electromagnetic reversing valve is connected to the oil pan, and under the action of the return spring, the rotary mechanism is pushed to move in the opposite direction, so that the piston boss is aligned with the end face of the plunger boss, and the stroke of the single pump plunger is controlled by the pump oil cam, and the system is in a rigid connection state.

2. The micro-injection ignition dual-fuel gas engine fuel supply system based on an electronically controlled unit pump as claimed in claim 1, characterized in that: A throttling device is arranged in the leakage control oil circuit.

3. The fuel supply system for a dual-fuel gas engine based on a micro-injection ignition pump and an electronically controlled unit pump as claimed in claim 1, characterized in that: An overflow valve is arranged in the leakage control oil circuit.

4. The fuel supply system for a micro-injection ignition dual-fuel gas engine based on an electronically controlled unit pump as claimed in claim 1, characterized in that: An overflow valve and a throttling device are arranged in the leakage control oil circuit, and the throttling device and the overflow valve are arranged in series.

5. The fuel supply system for a dual-fuel gas engine based on a micro-injection ignition pump and an electronically controlled unit pump as claimed in claim 1, characterized in that: A throttling device and a switch solenoid valve are arranged in the leakage control oil circuit, and the throttling device and the switch solenoid valve are arranged in series.

6. The fuel supply system for a micro-injection ignition dual-fuel gas engine based on an electronically controlled unit pump as claimed in claim 1, characterized in that: The piston is provided with a piston roller, and the piston roller abuts against the oil pump cam.

7. The fuel supply system for a micro-injection ignition dual-fuel gas engine based on an electronically controlled unit pump as claimed in claim 1, characterized in that: The linkage plunger couple includes a linkage plunger and a linkage plunger sleeve, the rotary mechanism includes a control gear and a rack that mesh with each other, the control gear is connected to the main plunger in a torque-transmitting manner, the return spring is a compression spring, and under the action of the return spring, the rack abuts against the linkage plunger.

8. The fuel supply system for a micro-injection ignition dual-fuel gas engine based on an electronically controlled unit pump as claimed in claim 7, characterized in that: The rack is a multi-cylinder rack, which is meshed with control gears of multiple main pistons at the same time.

9. The fuel supply system for a micro-injection ignition dual-fuel gas engine based on an electronically controlled unit pump as claimed in claim 1, characterized in that: The linkage plunger pair includes a linkage plunger and a linkage plunger sleeve, the rotary mechanism includes a control disk and a hinge pin, the control disk is connected to the main plunger in a torque-transmitting manner, the hinge pin is eccentrically fixed on the control disk, a transverse opening groove is provided on the linkage plunger, and the hinge pin is movably arranged in the transverse opening groove; the return spring is a tension spring connected to the linkage plunger, the tension spring is arranged in the linkage plunger sleeve, or the return spring is a compression spring, the compression spring rests on the outer side of the linkage plunger, or the return spring is a torsion spring, and the torsion spring is connected between the hinge pin and the control disk.

10. The fuel supply system for a micro-injection ignition dual-fuel gas engine based on an electronically controlled unit pump as claimed in claim 1, characterized in that: The linkage plunger pair includes a linkage plunger and a linkage plunger sleeve, the rotary mechanism includes a control disk and a hinge pin, the control disk is connected to the main plunger in a torque-transmitting manner, the hinge pin is fixed on the linkage plunger, a transverse opening groove is provided on the control disk, and the hinge pin is movably arranged in the transverse opening groove; the return spring is a tension spring connected to the linkage plunger, the tension spring is arranged in the linkage plunger sleeve, or the return spring is a compression spring, the compression spring rests on the outer side of the linkage plunger, or the return spring is a torsion spring, and the torsion spring is connected between the hinge pin and the control disk.

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