Pre-combustion chamber structure for self-adaptively adjusting geometric compression ratio of diesel engine

Abstract

The invention provides a pre-combustion chamber structure for self-adaptively adjusting the geometric compression ratio of a diesel engine, which comprises a pre-combustion chamber system arranged on an air cylinder, a pre-combustion chamber arranged in the pre-combustion chamber system, and the pre-combustion chamber is communicated with a main combustion chamber formed in the air cylinder and used for generating high-speed jet flow to assist the combustion of the diesel engine; the mode switching device is connected with the pre-combustion chamber system, the physical connection area between the pre-combustion chamber and the main combustion chamber is changed through mechanical linkage, and the mode switching device at least comprises a worm and gear transmission mechanism and a split type pneumatic / electric valve structure; and the control unit is electrically connected with the mode switching device, and the geometric compression ratio of the diesel engine is dynamically adjusted by controlling the mode switching device to act. The communication state of the pre-combustion chamber and the main combustion chamber and the working mode of the pre-combustion chamber are dynamically adjusted through multiple mechanical structures, self-adaptive adjustment of the geometric compression ratio of the diesel engine is met, and efficient and stable operation of the diesel engine within the full working condition range can be achieved.

Description

Technical Field

[0001] This application belongs to the technical field of internal combustion engine combustion, and particularly relates to a pre-chamber structure for adaptively adjusting the geometric compression ratio of a diesel engine. Background Technique

[0002] Pre-chambers are widely used in the field of internal combustion engines, especially in the field of natural gas engines. The pre-chamber jet ignition technology has the advantages of high-energy ignition, composite fuel, and mixture stratification, etc., and can improve the lean combustion performance of the engine and expand the lean combustion limit of the engine. At the same time, in the field of diesel engines, the pre-chamber jet disturbance enhanced combustion technology uses high-pressure jets to strongly disturb the mixture in the main combustion chamber, improves the in-cylinder fuel-air mixing quality, and then improves the combustion efficiency and power output of the diesel engine.

[0003] However, the pre-chamber itself occupies a certain space and is connected to the main combustion chamber through one or more small-diameter through holes, which will inevitably increase the clearance volume of the diesel engine combustion chamber. The increase in the clearance volume directly leads to a decrease in the compression ratio of the diesel engine, and the compression ratio is one of the key parameters affecting the performance of the diesel engine. When the application of the pre-chamber is only used as an auxiliary system of the diesel engine, from the perspective of the full operating conditions of the diesel engine, the pre-chamber does not play a positive role in all operating conditions. Taking the diesel engine with a jet disturbance enhanced combustion system as an example, at low load conditions, the fuel-air mixing energy in the cylinder is already excessive. At this time, injecting fuel inside the pre-chamber is not only unnecessary, but due to the resulting decrease in the compression ratio, it will have an adverse impact on the economy, power performance, and cold start performance of the diesel engine, increasing fuel consumption and reducing the output power.

[0004] Currently, experts and scholars have proposed to use a movable device to adjust the dead volume of the pre-chamber for gas engines, but it only stays at the conceptual design stage and there is no detailed and feasible driving mechanism layout scheme. Summary of the Invention

[0005] In view of this, the purpose of this application is to propose a pre-chamber structure for adaptively adjusting the geometric compression ratio of a diesel engine. By dynamically adjusting the connection state between the pre-chamber and the main combustion chamber and the working mode of the pre-chamber through a variety of mechanical structures, a two-mode pre-chamber structure for adaptively adjusting the geometric compression ratio of the diesel engine is realized, so as to solve the problem that the effective compression ratio of the diesel engine is reduced due to the volume of the pre-chamber when the pre-chamber does not need to work.

[0006] To achieve the above object, the technical solution of this application is realized as follows: This application provides a pre-chamber structure for adaptively adjusting the geometric compression ratio of a diesel engine, including: A pre-chamber system, which is arranged on the cylinder. A pre-chamber is provided inside the pre-chamber system. The pre-chamber is connected to the main combustion chamber formed inside the cylinder and is used to generate a high-speed jet to assist the combustion of the diesel engine under specific working conditions; A mode switching device, which is connected to the pre-chamber system and changes the physical connection area between the pre-chamber and the main combustion chamber through mechanical linkage. Wherein, the mode switching device at least includes a worm and worm gear transmission mechanism and a split pneumatic / electric valve structure; A control unit, which is electrically connected to the mode switching device and dynamically adjusts the geometric compression ratio of the diesel engine by controlling the action of the mode switching device.

[0007] Further, the pre-chamber system includes a pre-chamber adapter, a pre-chamber injector and a spark plug. Wherein, a cavity is reserved in the pre-chamber adapter to form a pre-chamber, and the pre-chamber injector and the spark plug are arranged in the pre-chamber adapter; A main combustion chamber injector is installed on the cylinder, and the main combustion chamber injector and the pre-chamber injector are connected to the high-pressure common rail system.

[0008] Further, the worm and worm gear transmission mechanism includes a screw plug, a worm wheel, a worm and a stepping motor. The main body of the screw plug is in a screw-like structure, and its head is in a hemispherical structure. The hemispherical structure cooperates with the assembly hole opened on one side of the pre-chamber adapter and extends into the pre-chamber. The worm wheel is connected to one end of the screw of the screw plug, the worm wheel is meshed with the worm, and the end of the worm is connected to the stepping motor through a coupling. The stepping motor is electrically connected to the control unit and the vehicle power supply.

[0009] Further, a matching stepped sealing structure is provided between the main body of the screw plug and the pre-chamber adapter, and a gasket or an O-ring is installed at the sealing structure.

[0010] Further, the split pneumatic valve structure includes a pneumatic gate valve. The valve body of the pneumatic gate valve is arranged on the pre-chamber adapter. The pneumatic gate valve is electrically connected to a high-pressure air source electric control valve, and the high-pressure air source electric control valve is electrically connected to the diesel engine-mounted air compressor, the high-pressure common rail system and the control unit respectively; The control unit controls the high-pressure air source electric control valve to make high-pressure gas act on the pneumatic gate valve to push it to open or close, so as to connect or block the channel between the pre-chamber and the main combustion chamber.

[0011] Further, the valve body of the pneumatic gate valve and the pre-chamber adapter are sealed by threaded connection, flange connection or welding.

[0012] Further, the split electric valve structure includes an electric gate valve. The electric gate valve is arranged on the pre-chamber adapter. The electric gate valve is connected to the vehicle-mounted low-voltage power supply and the control unit; The control unit controls the motor of the electric gate valve to open and close the electric gate valve, so as to connect or block the passage between the pre-combustion chamber and the main combustion chamber.

[0013] Further, the control unit collects the diesel engine working condition characteristic information in real time, judges the diesel engine working condition and the pre-combustion chamber working requirements according to the preset calibration result, and sends a control instruction to the mode switching device; wherein, the characteristic information at least includes the throttle opening, the rotational speed, the peak value of the cylinder pressure explosion pressure, and the exhaust gas analysis result.

[0014] Compared with the prior art, the pre-combustion chamber structure for adaptively adjusting the geometric compression ratio of a diesel engine according to the present application has the following beneficial effects: 1) Optimize the performance of the diesel engine under all working conditions: Through the two-mode pre-combustion chamber structure, the diesel engine can automatically switch the working state of the pre-combustion chamber according to different working conditions, give full play to its advantages under the working conditions where the pre-combustion chamber is required, improve the combustion efficiency and power output; under the working conditions where the pre-combustion chamber is not required, close the pre-combustion chamber passage in time, restore the compression ratio, avoid performance loss, so as to realize the efficient and stable operation of the diesel engine within the full working condition range.

[0015] 2) Improve fuel economy: When the pre-combustion chamber does not need to work under partial load conditions, restoring the compression ratio can effectively reduce fuel consumption and improve fuel economy. At the same time, under other working conditions, the normal operation of the pre-combustion chamber also helps to optimize the combustion process, further improve the fuel utilization rate, and reduce energy waste.

[0016] 3) Strong structural selectivity and high reliability: It can be reasonably selected according to the actual situation of different diesel engines, has strong adaptability and versatility, and can meet the needs of different types of diesel engines. Among them, the screw plug type structure is based on the mature worm and worm drive and screw translation principle, and the pneumatic gate valve type and electric gate valve type structures adopt common valve control methods; these structures are widely used in the mechanical and electrical fields, have high reliability, and can operate stably in the complex working environment of the diesel engine, reducing the probability of failure.

[0017] 4) Simple control strategy: The requirements for the speed accuracy of the rod-shaped plug and the gate valve are not high, the load torque change of the stepping motor and the valve is small, and the open-loop control method can be adopted. The diesel engine ECU sends a control signal to the stepping motor or the valve through the CAN bus, and the modification of the diesel engine control system is limited. The control strategy of the two-mode pre-combustion chamber is very simple. Description of the Drawings

[0018] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings: Figure 1Schematic structural diagram of the pre - combustion chamber structure with a screw plug according to the embodiment of the present application; Figure 2 Schematic structural diagram of the pre - combustion type structure with a pneumatic gate valve according to the embodiment of the present application; Figure 3 Schematic structural diagram of the pre - combustion type structure with an electric gate valve according to the embodiment of the present application; Figure 4 Schematic control diagram of the control unit according to the embodiment of the present application.

[0019] Explanation of reference numerals: 1 - Pre - combustion chamber; 2 - Pre - combustion chamber injector; 3 - Spark plug; 4 - Screw plug; 5 - Worm gear; 6 - Worm; 7 - Coupling; 8 - Stepper motor; 9 - Cylinder head; 10 - Intake pipe; 11 - Exhaust pipe; 12 - Main combustion chamber injector; 13 - Pre - combustion chamber system; 14 - Pneumatic gate valve; 15 - High - pressure common - rail pipe; 16 - High - pressure oil pump; 17 - Control unit; 18 - Diesel - engine - mounted air compressor; 19 - High - pressure air - source electric control valve; 20 - Electric gate valve; 21 - Vehicle - mounted low - voltage power supply. Detailed implementation manners

[0020] To make the objectives, technical solutions and advantages of the present application clearer and more understandable, the following further elaborates on the present application in detail with reference to specific embodiments and the accompanying drawings.

[0021] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the ordinary meanings understood by those with ordinary skills in the field to which the present application belongs. The terms "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. Words such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0022] Please refer to Figures 1 to 4 As shown, this embodiment provides a pre - combustion chamber 1 structure for adaptively adjusting the geometric compression ratio of a diesel engine, including: A pre - combustion chamber system 13, which is arranged on the cylinder. The pre - combustion chamber system 13 is provided with a pre - combustion chamber 1. The pre - combustion chamber 1 is connected to the main combustion chamber formed in the cylinder and is used to generate a high - speed jet to assist the combustion of the diesel engine under specific working conditions; The mode switching device is connected to the pre-chamber system 13 and changes the physical connection area between the pre-chamber 1 and the main combustion chamber through mechanical linkage. Among them, the mode switching device at least includes a worm and worm gear 6 transmission mechanism and a split pneumatic / electric valve structure; The control unit 17 is electrically connected to the mode switching device and dynamically adjusts the geometric compression ratio of the diesel engine by controlling the operation of the mode switching device.

[0023] Specifically, in this embodiment, the present application aims to solve the problem that the compression ratio of the existing diesel engine system with a pre-chamber 1 structure decreases due to an increase in the clearance volume. By designing an innovative pre-chamber 1 structure, through the hierarchical action of the worm and worm gear 6 transmission mechanism or the split valve, the screw plug 4 is driven by the worm and worm gear 6 to translate to block or open the channel; the pneumatic gate valve 14 controls the opening and closing of the gate valve with the help of a high-pressure gas source and a reset device; the electric gate valve 20 realizes the valve action by being driven by a motor; when blocking the pre-chamber 1 channel, the clearance volume is reduced to more than 95% of the original design, so that the compression ratio is restored to within the range of the target value ±2%, realizing the flexible application of the pre-chamber 1 under different working conditions, and maximizing the comprehensive application effect of the pre-chamber 1 structure on the internal combustion engine.

[0024] At the same time, it is ensured that during the full-load operation of the diesel engine, the advantages of the pre-chamber 1 in igniting lean mixtures or improving the fuel-air mixture in different diesel engine combustion systems can be fully utilized, and the performance loss caused by the pre-chamber 1 structure under certain working conditions can be avoided, thereby optimizing the overall performance of the diesel engine and improving fuel economy and power output stability.

[0025] In some embodiments, the pre-chamber system 13 includes a pre-chamber 1 adapter, a pre-chamber 1 injector, and a spark plug 3. Among them, a cavity is reserved in the pre-chamber 1 adapter to form the pre-chamber 1, and the pre-chamber 1 injector and the spark plug 3 are arranged in the pre-chamber 1 adapter; A main combustion chamber injector 12 is installed on the cylinder. The main combustion chamber injector 12 and the pre-chamber 1 injector are connected to a high-pressure common rail system (the high-pressure common rail system includes a high-pressure common rail pipe 15 and a high-pressure oil pump 16 connected to each other).

[0026] Specifically, in this embodiment, as Figure 1 shown, the bottom of the pre-chamber 1 adapter is provided with an inverted conical cavity to form the pre-chamber 1, and the pre-chamber 1 injector and the spark plug 3 are installed on the top of the pre-chamber 1. The cylinder is composed of a cylinder block and a cylinder head, and a closed main combustion chamber is formed inside. The main combustion chamber is respectively connected to an intake pipe 10 and an exhaust pipe 11. At the same time, the main combustion chamber injector 12 is installed on the cylinder head 9, and the pre-chamber 1 adapter is installed on the cylinder, and the pre-chamber 1 is connected to the main combustion chamber.

[0027] In some embodiments, the worm and worm gear transmission mechanism includes a screw plug 4, a worm gear 5, a worm 6, and a stepper motor 8. The main body of the screw plug is in the shape of a screw, and its head is in the shape of a hemisphere. The hemisphere-shaped structure fits with the assembly hole opened on the side of the pre-chamber 1 that is adapted, and extends into the pre-chamber 1. The worm gear 5 is connected to the screw end of the screw plug 4. The worm gear 5 is meshed with the worm 6. The end of the worm 6 is connected to the stepper motor 8 through a coupling 7. The stepper motor 8 is electrically connected to the control unit 17 and the vehicle power supply. As Figure 1 It only shows the connection structure between the worm and worm gear and the pre-chamber 1, and does not show the specific connection relationship with the high-pressure common rail system and the control unit 17; A matching stepped sealing structure is provided between the main body of the screw plug and the pre-chamber 1 that is adapted, and a gasket or an O-ring is installed at the sealing structure.

[0028] Specifically, in this embodiment, as Figure 1 shown, taking the inverted conical pre-chamber 1 as an example, the head of the screw plug 4 is designed as a hemispherical head, the main body of the screw plug 4 is in the shape of a screw, one end of the screw is connected to the worm gear, the worm gear and the worm 6 are meshed with each other, and the worm and worm gear 6 transmission mechanism realizes precise displacement control through the stepper motor 8; a circular assembly hole is reserved on the side of the pre-chamber 1, and the screw plug 4 is installed in the assembly hole and can rotate and translate in the hole. When the stepper motor 8 drives the worm 6 to rotate, the screw plug 4 is driven by the worm gear to translate, so that the hemispherical head enters or exits the pre-chamber 1, realizing the blocking or opening of the channel between the pre-chamber 1 and the main combustion chamber, and ensuring that the clearance volume is reduced to the design compression ratio range of the main combustion chamber when the channel is blocked.

[0029] When the diesel engine is in a working condition where the pre-chamber 1 is not required, the control unit 17 (ECU) of the diesel engine issues a signal to drive the stepper motor 8 according to the pre-calibrated working condition data. The stepper motor 8 drives the worm 6 to rotate, and then the screw structure is translated forward through the worm gear, and the hemispherical plug gradually enters the pre-chamber 1, finally completely blocking the channel between the pre-chamber 1 and the main combustion chamber, thereby restoring the original design geometric compression ratio of the diesel engine or reducing the influence on the geometric compression ratio. When the diesel engine is in a working condition where the pre-chamber 1 is required, the stepper motor 8 rotates in the reverse direction, and the screw structure retreats through the worm and worm gear mechanism, the hemispherical head exits the pre-chamber 1, the channel between the pre-chamber 1 and the main combustion chamber is reopened, and the pre-chamber 1 returns to the normal working state. The screw plug type structure is suitable for high-precision compression ratio adjustment scenarios and has better sealing performance than traditional valves.

[0030] It should be noted that when the screw plug structure is adopted, the sealing of the side assembly hole of the pre-chamber 1 needs to be considered. Specifically, in the middle area of the screw rod, that is, when the sealing head is fully in place, in the area where the screw rod is in external contact with the pre-chamber 1 in a matching manner, a shape that can fit the external part of the pre-chamber 1 is designed. In this embodiment, a stepped sealing structure is adopted, and a sealing gasket or O-ring is added in the middle according to the actual diesel engine for sealing.

[0031] Taking the worm and worm gear transmission mechanism of the screw plug 4 type as an example: Structure installation and debugging: Taking the structure of the inverted conical pre-chamber 1 as an example, during the manufacture or modification of the diesel engine, first, according to the design requirements, a circular assembly hole is accurately machined on the side of the pre-chamber 1 to ensure that its dimensional accuracy and position accuracy meet the design standards. The screw plug structure is installed in the circular hole to ensure that it can rotate and translate flexibly in the hole. The worm and worm gear 6 mechanism is installed, and the worm gear is reliably connected to one end of the screw rod of the screw plug 4 to ensure stable transmission between the two. Then, the worm 6 and the stepping motor 8 are installed, and the meshing clearance between the worm 6 and the worm gear is adjusted to make the transmission smooth. At the same time, the stepping motor 8 is electrically connected to the ECU of the diesel engine and the vehicle power supply to ensure accurate signal transmission. After the installation is completed, comprehensive debugging work is carried out.

[0032] By manually operating the stepping motor 8, check whether the movement of the screw plug 4 is smooth and whether it can accurately block and open the passage between the pre-chamber 1 and the main combustion chamber. At the same time, perform an initialization setting on the ECU of the diesel engine, input the pre-calibrated operating condition data and control parameters to ensure that the ECU can accurately control the operation of the stepping motor 8 according to the actual operating conditions of the diesel engine.

[0033] Working mode switching during the operation of the diesel engine: When the diesel engine starts and enters the operating state, the control unit 17 ECU real-time collects various operating condition parameters of the diesel engine, such as speed, load, throttle opening, etc. According to the pre-calibrated operating condition judgment logic, the ECU analyzes whether the current operating condition of the diesel engine requires the pre-chamber 1 to work. When the ECU judges that the pre-chamber 1 does not need to work at this time, it immediately sends a control signal to the stepping motor 8. The stepping motor 8 rotates according to a predetermined program, drives the worm 6 to rotate, and then pushes the rod-shaped plug forward through the worm gear. The hemispherical head gradually enters the pre-chamber 1 until the passage between the pre-chamber 1 and the main combustion chamber is completely blocked, completing the operation of restoring the compression ratio. During the entire operation of the diesel engine, the ECU continuously monitors the operating condition parameters and timely switches the working mode of the pre-chamber 1 according to the needs to ensure that the diesel engine is always in the best operating state.

[0034] In some embodiments, the split pneumatic valve structure includes a pneumatic gate valve 14. The valve body of the pneumatic gate valve 14 is disposed on the mating part of the pre-chamber 1. The pneumatic gate valve 14 is electrically connected to the high-pressure air source electric control valve 19, and the high-pressure air source electric control valve 19 is respectively electrically connected to the diesel engine-mounted air compressor 18, the high-pressure common rail system, and the control unit 17. The control unit 17 controls the high-pressure air source electric control valve 19 to make the high-pressure gas act on the pneumatic gate valve 14 to push it to open or close, so as to connect or block the passage between the pre-chamber 1 and the main combustion chamber. The valve body of the pneumatic gate valve 14 and the mating part of the pre-chamber 1 are sealed by thread connection, flange connection or welding.

[0035] Specifically, in this embodiment, as Figure 2 shown, a pneumatic gate valve 14 is added in the middle of the cavity of the pre-chamber 1. The valve body of the gate valve is connected to the mating part of the pre-chamber 1 by a screw. It also includes a high-pressure air source, a high-pressure air source electric control valve 19, and a reset device. When it is necessary to close the passage, the ECU of the diesel engine controls the high-pressure air source valve to make the high-pressure gas act on the gate valve to push the gate valve to close and block the passage between the pre-chamber 1 and the main combustion chamber. When it is necessary to open the passage, the ECU controls the high-pressure air source valve to change the gas flow direction or stop supplying air, and the gate valve opens under the action of the reset device (such as a spring, etc.), and the passage between the pre-chamber 1 and the main combustion chamber is reopened.

[0036] It should be noted that the pneumatic gate valve 14 in this embodiment can be a wedge valve or a parallel valve, and can also be a single-layer or double-layer valve. This solution requires the diesel engine to be equipped with an air compressor that can stably provide more than 3 bar of compressed air to ensure that the gate valve can work normally. The pneumatic gate valve 14 structure has a faster response speed and is suitable for frequently switching working conditions.

[0037] The seal between the valve body and the pre-chamber 1 is adopted by thread connection seal, flange connection seal or welding seal method; when using thread connection seal, sealing material is wound at the thread; when using flange connection seal, gaskets made of materials such as asbestos rubber or polytetrafluoroethylene are placed between the flange sealing surfaces.

[0038] Taking the split pneumatic valve structure as an example: Structure Installation and Debugging: Install the pneumatic gate valve 14 at a suitable position in the middle of the pre-chamber 1 cavity to ensure that the screw connection between the gate valve and the pre-chamber 1 is firm and well-sealed. Connect the high-pressure gas source pipeline, connect the high-pressure gas source (such as the air compressor equipped with the diesel engine) to the control end of the gate valve, and install the corresponding valves and control components. Debug the high-pressure gas source system to ensure that it can stably supply compressed air above 3 bar. Connect the control signal line of the gate valve to the ECU of the diesel engine to ensure that the ECU can accurately control the opening and closing of the gate valve. After the installation is completed, conduct a comprehensive debugging work. Manually control the high-pressure gas source valve to check whether the opening and closing of the gate valve are smooth and whether the sealing performance is good. At the same time, initialize the ECU of the diesel engine, input the pre-calibrated working condition data and control parameters to ensure that the ECU can accurately control the high-pressure gas source valve according to the actual working conditions of the diesel engine, and then control the working state of the gate valve.

[0039] Working Mode Switching during Diesel Engine Operation: When the diesel engine starts and enters the operating state, the ECU real-time collects the working condition parameters of the diesel engine. When it is judged that the diesel engine is in a working condition where the pre-chamber 1 does not need to work, the ECU sends a control signal to the high-pressure gas source valve, so that the high-pressure gas enters the control end of the gate valve, pushing the gate valve to close and blocking the channel between the pre-chamber 1 and the main combustion chamber. When the working condition of the diesel engine changes and enters a working condition where the pre-chamber 1 needs to work, the ECU controls the high-pressure gas source valve to change the gas flow direction or stop supplying gas, and the gate valve opens under the action of the reset device, and the channel between the pre-chamber 1 and the main combustion chamber is reopened. During the whole process, the ECU continuously monitors the working conditions of the diesel engine and timely switches the working mode of the pre-chamber 1 according to the needs to ensure the efficient operation of the diesel engine.

[0040] In some embodiments, the split-type electric valve structure includes an electric gate valve 20, the electric gate valve 20 is arranged on the pre-chamber 1 adapter, and the electric gate valve 20 is connected to the vehicle-mounted low-voltage power supply 21 and the control unit 17; The control unit 17 controls the motor action of the electric gate valve 20 to control the opening and closing of the electric gate valve 20 to connect or block the channel between the pre-chamber 1 and the main combustion chamber.

[0041] Specifically, in this embodiment, as Figure 3As shown in the figure, an electric gate valve 20 is added in the middle of the cavity of the pre-chamber 1, eliminating the problems of high-pressure gas source and gas circuit layout. The electric gate valve 20 is driven by a motor to open and close the valve, and its working principle is the same as that of the pneumatic gate valve 14. When the diesel engine is in a working condition where the pre-chamber 1 is not required to work, the ECU controls the motor of the electric gate valve 20 to act, closing the gate valve and blocking the passage between the pre-chamber 1 and the main combustion chamber; when the diesel engine is in a working condition where the pre-chamber 1 is required to work, the ECU controls the motor to act in the reverse direction, opening the gate valve and reopening the passage between the pre-chamber 1 and the main combustion chamber. The electric gate valve 20 has an independent structure independent of the gas source and stronger compatibility.

[0042] Taking the split-type electric valve structure as an example: Structure installation and debugging: Install the electric gate valve 20 at a suitable position in the middle of the cavity of the pre-chamber 1 to ensure a firm and well-sealed connection between the gate valve and the pre-chamber 1. Connect the motor control line of the electric gate valve 20 to the ECU of the diesel engine to ensure that the ECU can accurately control the forward and reverse rotation of the motor, thereby realizing the opening and closing of the gate valve. After the installation is completed, carry out a comprehensive debugging work. Manually operate the ECU to control the motor of the electric gate valve 20, check whether the opening and closing of the gate valve are smooth and whether the sealing performance is good; at the same time, perform an initialization setting on the ECU of the diesel engine, input the pre-calibrated working condition data and control parameters, and ensure that the ECU can accurately control the action of the motor of the electric gate valve 20 according to the actual working condition of the diesel engine, and then control the working state of the gate valve.

[0043] Working mode switching during the operation of the diesel engine: When the diesel engine starts and enters the running state, the ECU real-time collects the working condition parameters of the diesel engine. When it is judged that the diesel engine is in a working condition where the pre-chamber 1 is not required to work, the ECU sends a control signal to the motor of the electric gate valve 20 to make the motor act to close the gate valve and block the passage between the pre-chamber 1 and the main combustion chamber. When the working condition of the diesel engine changes and enters a working condition where the pre-chamber 1 is required to work, the ECU controls the motor of the electric gate valve 20 to act in the reverse direction, opening the gate valve and reopening the passage between the pre-chamber 1 and the main combustion chamber. During the entire operation of the diesel engine, the ECU continuously monitors the working condition parameters and timely switches the working mode of the pre-chamber 1 according to the needs to ensure that the diesel engine is always in the best running state.

[0044] In some embodiments, the control unit 17 real-time collects the diesel engine working condition characteristic information, judges the diesel engine working condition and the working requirement of the pre-chamber 1 according to the preset calibration result, and sends a control instruction to the mode switching device; wherein, the characteristic information at least includes the throttle opening, rotational speed, peak cylinder pressure explosion pressure, and exhaust gas analysis result.

[0045] Specifically, in this embodiment, as Figure 4As shown, the diesel engine operating condition characteristic information collected by the control unit 17 includes, but is not limited to, throttle opening, rotational speed, peak cylinder pressure, and the results of a portable emission analyzer. Using an open-loop control method, control signals are sent to the mode switching devices such as the stepper motor 8, pneumatic valve, electronically controlled valve, or electric valve in the mode switching device via the CAN bus.

[0046] And according to the previous calibration results, the pre-chamber 1 is controlled to adaptively adjust the actuator, including the working state of the stepper motor 8, the opening and closing of the pneumatic gate valve 14, the electronically controlled valve 19 of the high-pressure air source, and the opening and closing of the electric valve gate.

[0047] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the specification of the present invention.

[0048] The embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the embodiments of the present application shall be included within the protection scope of the present application.

Claims

1. A pre-combustion chamber structure for adaptively adjusting the geometric compression ratio of a diesel engine, characterized in that: include: A pre-combustion chamber system, which is arranged on the cylinder, wherein a pre-combustion chamber is provided in the pre-combustion chamber system, wherein the pre-combustion chamber is connected to a main combustion chamber formed in the cylinder, and is used to generate a high-speed jet to assist the combustion of the diesel engine under specific working conditions; A mode switching device, the mode switching device is connected to the pre-combustion chamber system, and changes the physical connection area between the pre-combustion chamber and the main combustion chamber through mechanical linkage, wherein the mode switching device at least includes a worm gear transmission mechanism and a split pneumatic / electric valve structure; A control unit is electrically connected to the mode switching device and controls the operation of the mode switching device to dynamically adjust the geometric compression ratio of the diesel engine.

2. The pre-combustion chamber structure for adaptively adjusting the geometric compression ratio of a diesel engine according to claim 1, characterized in that: The pre-combustion chamber system comprises a pre-combustion chamber adapter, a pre-combustion chamber injector and a spark plug, wherein a cavity is reserved in the pre-combustion chamber adapter to form a pre-combustion chamber, and the pre-combustion chamber injector and the spark plug are arranged in the pre-combustion chamber adapter; A main combustion chamber injector is installed on the cylinder, and the main combustion chamber injector and the pre-combustion chamber injector are connected to a high-pressure common rail system.

3. The pre-combustion chamber structure for adaptively adjusting the geometric compression ratio of a diesel engine according to claim 2, characterized in that: The worm gear transmission mechanism includes a screw plug, a worm wheel, a worm and a stepper motor. The main body of the screw plug is a screw-shaped structure, and its head is a hemispherical structure. The hemispherical structure cooperates with the assembly hole opened on one side of the pre-combustion chamber adapter and extends into the pre-combustion chamber. The worm wheel is connected to one end of the screw of the screw plug, the worm wheel is meshingly connected to the worm, and the end of the worm is connected to the stepper motor through a coupling. The stepper motor is electrically connected to the control unit and the vehicle power supply.

4. The pre-combustion chamber structure for adaptively adjusting the geometric compression ratio of a diesel engine according to claim 3 is characterized in that: A matching stepped sealing structure is provided between the screw plug body and the pre-combustion chamber adapter, and a sealing gasket or an O-ring is installed at the sealing structure.

5. The pre-combustion chamber structure for adaptively adjusting the geometric compression ratio of a diesel engine according to claim 2, characterized in that: The split-type pneumatic valve structure comprises a pneumatic gate valve, the valve body of the pneumatic gate valve is arranged on the pre-combustion chamber adapter, the pneumatic gate valve is electrically connected to the high-pressure gas source electric control valve, and the high-pressure gas source electric control valve is electrically connected to the diesel engine-borne air compressor, the high-pressure common rail system and the control unit respectively; The control unit controls the high-pressure gas source electrically controlled valve so that the high-pressure gas acts on the pneumatic gate valve to push it to open and close, so as to connect or block the passage between the pre-combustion chamber and the main combustion chamber.

6. The pre-combustion chamber structure for adaptively adjusting the geometric compression ratio of a diesel engine according to claim 5, characterized in that: The pneumatic gate valve body and the pre-combustion chamber adapter are sealed by threaded connection, flange connection or welding.

7. The pre-combustion chamber structure for adaptively adjusting the geometric compression ratio of a diesel engine according to claim 2, characterized in that: The split electric valve structure includes an electric gate valve, which is arranged on the pre-combustion chamber adapter, and the electric gate valve is connected to the vehicle-mounted low-voltage power supply and the control unit; The control unit controls the motor movement of the electric gate valve, and controls the opening and closing of the electric gate valve to connect or block the passage between the pre-combustion chamber and the main combustion chamber.

8. The pre-combustion chamber structure for adaptively adjusting the geometric compression ratio of a diesel engine according to claim 1, characterized in that: The control unit collects diesel engine operating condition characteristic information in real time, determines the diesel engine operating condition and pre-combustion chamber working requirements according to preset calibration results, and sends control instructions to the mode switching device; wherein the characteristic information includes at least throttle opening, speed, cylinder pressure explosion pressure peak and exhaust gas analysis results.

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