Electric fuel injection timing adjustment device

Abstract

The application belongs to the technical field of diesel engine adjusting device, and particularly relates to an electric fuel injection timing adjusting device, which comprises a shell, a spiral shaft, a tapered roller bearing, a bearing cover, a spiral sleeve, a spline guide sleeve, a fixing cover, a push-pull screw rod, a threaded sleeve and an end cover. The spiral transmission and spline guide combination structure is adopted, the design feature that the helix angle is greater than the friction angle is utilized, the force transmission efficiency in the transmission process and the reversibility of the movement direction are ensured, the rotation movement output by the driving device is efficiently converted into the accurate rotation of the spiral shaft, the spiral transmission cannot be reversely driven, self-locking is realized, the forward driving is not affected by the self-locking, the problems of adjustment lag and insufficient precision caused by the self-locking phenomenon in the traditional adjusting device are effectively avoided, the overall structure is compact, and the components are stably and reliably cooperated.

Description

Technical Field

[0001] This invention belongs to the technical field of diesel engine adjustment devices, specifically an electric fuel injection timing adjustment device. Background Technology

[0002] During diesel engine operation, fuel injection timing has a crucial impact on its power, economy, and emissions performance. Traditional fuel injection timing adjustment devices mostly employ mechanical transmission or hydraulic drive, which suffer from problems such as complex structure, slow response speed, and low adjustment accuracy. Mechanical transmission adjustment devices typically rely on the mechanical linkage of the camshaft or crankshaft, and their adjustment range is limited and cannot be dynamically and accurately adjusted according to real-time operating conditions. Although hydraulic drive adjustment devices offer improved response speed, the hydraulic system is susceptible to fluctuations in oil temperature and pressure, leading to adjustment lag and insufficient stability, and there is also a risk of hydraulic oil leakage, increasing maintenance costs. In addition, due to limitations in the transmission structure design, some traditional adjustment devices are prone to self-locking during adjustment, further exacerbating the problems of adjustment lag and insufficient accuracy, making it difficult to meet the demands of modern diesel engines for efficient and precise fuel injection control.

[0003] Chinese invention patent application CN102392741A discloses an electric fuel injection timing adjustment device. In this patent, the electric fuel injection timing adjustment device includes a housing, within which a shaft and a push rod shaft are disposed. One end of the push rod shaft is fitted inside the shaft and rotates relative to it. The push rod shaft is connected to a reducer and its rotation is controlled by the reducer. The rotation of the push rod shaft causes it to move relative to the housing, and the shaft moves with the push rod shaft. This electric fuel injection timing adjustment device in the patent can achieve automatic adjustment of fuel injection timing. Its transmission structure uses a push rod shaft rotatably connected to the shaft, but the specific connection method between the shaft and the housing is not specified. Therefore, it is impossible to determine whether the shaft has a circumferential limit. If no circumferential limit is provided, the shaft will not be able to achieve the desired adjustment when driving the cam's rotation. If other drive structures are used, a self-locking structure with a screw drive is required; otherwise, a reverse drive phenomenon may occur under external load reaction force, resulting in insufficient stability of the adjustment position. Furthermore, while the patent discloses the implementation of diesel engine performance testing and fault diagnosis functions in its effects description, no relevant content was found in the patent documents. Consequently, it is difficult to achieve closed-loop precise control and adaptive adjustment of injection timing, and thus cannot meet the higher requirements of modern diesel engines for dynamic response speed and control accuracy of injection timing under complex operating conditions. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention proposes an electric fuel injection timing adjustment device. This invention primarily addresses the problems of insufficient adjustment accuracy, slow response speed, and susceptibility to positional instability caused by load reaction forces in existing fuel injection timing adjustment devices.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: This invention provides an electric fuel injection timing adjustment device, including a housing, a spiral shaft, a tapered roller bearing, a bearing cover, a spiral sleeve, a spline guide sleeve, a fixing cover, a push-pull screw, a threaded sleeve, and an end cover; the housing has a cavity inside for accommodating the various components; the spiral shaft is arranged axially along the housing, and one end of the spiral shaft is rotatably connected to the housing through the tapered roller bearing; the outer ring of the tapered roller bearing abuts against the inner wall of one end of the housing, and the inner ring is fitted onto the spiral shaft; the bearing cover is fixed to the end of the housing by bolts for axial positioning of the tapered roller bearing; the spiral sleeve is fitted onto the housing. The spiral sleeve is external to the spiral shaft and is engaged with the spiral shaft by a thread with a helix angle greater than the friction angle; the spline guide sleeve is fixedly connected to the outer wall of the spiral sleeve; an axially extending guide groove is provided on the inner wall of the middle part of the housing; the spline guide sleeve is slidably connected in the guide groove; the fixed cover is fixedly connected to the end of the spiral sleeve; one end of the push-pull screw is rotatably connected to the fixed cover; the other end of the push-pull screw extends to the outside of the housing; the threaded sleeve is fitted on the push-pull screw and is threadedly connected to the push-pull screw; the threaded sleeve is fixedly connected to the end cover; the end cover is fixedly connected to the end face of the other end of the housing.

[0006] During operation, the threaded sleeve remains stationary with the end cover. When the reducer of the drive unit rotates the push-pull screw, due to the threaded engagement between the push-pull screw and the threaded sleeve, the push-pull screw moves linearly along its own axis. This movement of the push-pull screw causes the fixed cover, which is rotatably connected to it, to move synchronously. The fixed cover then pushes the screw sleeve axially. Because the spline guide sleeve is slidably connected to the guide groove on the housing, the rotational freedom of the screw sleeve is restricted, allowing it to only perform axial translation. During axial movement, the screw sleeve, through helical transmission with the screw shaft, and with the helix angle of the helical transmission greater than the friction angle, ensures that the axial thrust can be converted into circumferential rotation, ensuring the reverse motion of the helical transmission, which in turn drives the screw shaft to rotate. The rotation of the screw shaft is ultimately transmitted to the diesel engine's fuel injection system through the camshaft fixedly connected to the end, thereby achieving precise adjustment of the fuel injection timing. Because the camshaft cooperates with the intake and exhaust valves of the fuel injection system, adjusting the camshaft angle allows adjustment of the start and close times of each valve, thus adjusting the advance angle and keeping the diesel engine in optimal condition.

[0007] This solution employs a combination of helical drive and spline guidance, utilizing the design characteristic that the helix angle is greater than the friction angle to ensure efficient force transmission and reversibility of motion direction during the transmission process. This efficiently converts the rotational motion output by the drive unit into precise rotation of the helical shaft. Simultaneously, the helical drive cannot be reversed, thus achieving self-locking. Forward drive is unaffected by self-locking, effectively avoiding the adjustment lag and insufficient precision problems caused by self-locking in traditional adjustment devices. The overall structure is compact, and the components work together stably and reliably, providing a rapid-response and precise control technical solution for the dynamic adjustment of diesel engine injection timing.

[0008] Preferably, a gap-eliminating sleeve is provided at one end of the spiral sleeve; the gap-eliminating sleeve is fitted outside the spiral shaft and is engaged with the spiral shaft by a thread with a helix angle greater than the friction angle; the gap-eliminating sleeve and the spiral sleeve are pressed together by an axial limiting snap spring.

[0009] During operation, the clearance-eliminating sleeve and the spiral sleeve are both fitted onto the spiral shaft, and both are engaged with the spiral shaft via threads with a helix angle greater than the friction angle. As the spiral sleeve moves axially under the push-pull screw, the clearance-eliminating sleeve remains in contact with the spiral sleeve under the clamping force of the axial limiting spring. This clamping relationship effectively eliminates the axial clearance between the spiral sleeve and the spiral shaft caused by machining and assembly errors, as well as the spiral drive clearance. This avoids problems such as lag in spiral shaft rotation or decreased adjustment accuracy caused by clearance during transmission, further improving the accuracy and stability of fuel injection timing adjustment. After a period of use and wear, the new clearance caused by wear can be compensated by replacing it with a thicker axial limiting spring, thereby extending the service life of the device and maintaining long-term adjustment accuracy.

[0010] Preferably, both ends of the axial limiting snap ring are provided with snap-fit ​​structures; the snap-fit ​​structure is formed by the outer arc diameter of the axial limiting snap ring being greater than the inner diameter and protruding inward; the outer arc diameter of the axial limiting snap ring is smaller than the outer diameter of the spiral sleeve.

[0011] The outer diameter of the axial limiting snap ring is smaller than that of the spiral sleeve, ensuring that the overall structure of the axial limiting snap ring does not protrude from the outer surface of the spiral sleeve. This prevents interference with the inner wall of the housing or other components during the axial movement of the spiral sleeve, ensuring smooth operation of the device. Furthermore, by incorporating snap-fit ​​structures at both ends of the axial limiting snap ring, convenient installation and removal are achieved by opening and closing the snap-fit ​​structures, ensuring no interference. This significantly simplifies the maintenance process and reduces the time and labor costs of daily maintenance. Simultaneously, the snap-fit ​​structure design ensures that the axial limiting snap ring maintains stable radial tension after installation, guaranteeing a continuous and reliable clamping effect on the gap-eliminating sleeve and preventing the risk of gap-eliminating function failure due to loosening of the axial limiting snap ring.

[0012] Preferably, the helix angle of the mating thread between the spiral sleeve and the spiral shaft is greater than the friction angle of 5-10°.

[0013] During operation, the helix angle of the threaded connection between the helical sleeve and the helical shaft is set to be 5-10° greater than the friction angle. This design, while ensuring the helical drive can achieve reverse motion, further improves transmission efficiency and power transmission reliability. Compared to designs with an angle only slightly greater than the friction angle, the 5-10° difference effectively reduces the adverse effects of machining errors, changes in lubrication conditions, or instantaneous load fluctuations on the reverse motion of the helical drive. This ensures that under various operating conditions, the axial movement of the helical sleeve can be stably and accurately converted into the rotation of the helical shaft, avoiding transmission jamming or response delays. Simultaneously, this angle difference design also reduces friction and wear between the helical surfaces to a certain extent, extending the service life of the helical drive pair, thereby ensuring the long-term stability and adjustment accuracy of the fuel injection timing adjustment device.

[0014] Preferably, the fixing cover has a mounting hole in the middle, and a thrust ball bearing is provided on each side of the fixing cover; the locking screw passes through the thrust ball bearing and the fixing cover and is locked to the end of the push-pull screw.

[0015] During operation, the thrust ball bearings on both sides of the fixed cover are located at the two ends of the mounting hole. After the locking screws lock the end of the push-pull screw to the fixed cover, the inner ring of the thrust ball bearing rotates synchronously with the push-pull screw, while the outer ring remains relatively stationary with respect to the fixed cover. This structural design transforms the rotational connection between the push-pull screw and the fixed cover into the rolling friction of the thrust ball bearing, significantly reducing the frictional resistance and wear between them. This ensures that the push-pull screw can flexibly drive the fixed cover to move axially during rotation, avoiding motion jamming or component overheating caused by direct contact friction. At the same time, the thrust ball bearing can effectively withstand the bidirectional axial load generated by the push-pull screw during axial movement, ensuring stable and reliable thrust transmission between the fixed cover and the screw sleeve, further improving the smoothness of the entire adjustment device's movement and its service life.

[0016] Preferably, the fixed cover has a plurality of oil passage holes evenly spaced along the circumference at positions corresponding to the inside of the spiral sleeve; the diameter of the oil passage holes is 2-4mm, and the inner wall of the oil passage holes has a rounded corner transition structure.

[0017] During operation, lubricating oil is injected into the housing through the oil injection channel. As the spiral sleeve moves axially, the internal spaces of the housing at both ends of the spiral sleeve and the internal space of the spiral sleeve itself are constantly changing, creating a pressure difference. This pressure difference drives the lubricating oil through the oil passages on the fixed cover into the spiral sleeve. These oil passages evenly guide the lubricating oil to the threaded mating surfaces between the spiral sleeve and the spiral shaft, and between the clearance-eliminating sleeve and the spiral shaft, forming a continuous and effective lubricating film. The evenly distributed oil passage design ensures that each lubrication point receives sufficient lubricating oil, avoiding dry friction or increased wear caused by insufficient lubrication in certain areas. Excess lubricating oil also carries away the heat generated by friction, providing a cooling effect and further improving the stability and durability of the device.

[0018] The diameter of the oil passage hole is 2-4mm, and the inner wall of the oil passage hole is provided with a rounded transition structure. The diameter of 2-4mm ensures that there is enough lubricating oil to enter the spiral sleeve through the oil passage hole to meet the lubrication requirements of the threaded mating surface, while avoiding excessive lubricating oil loss or insufficient pressure difference due to an excessively large diameter, which would affect the lubrication effect. The rounded transition structure of the inner wall of the oil passage hole can eliminate stress concentration at the orifice, preventing cracks or damage at the edge of the oil passage hole due to stress concentration during long-term use. At the same time, it can also reduce the resistance of lubricating oil during the flow process, allowing the lubricating oil to enter the lubrication area more smoothly, further optimizing the lubrication effect and ensuring the long-term stable operation of the device.

[0019] Preferably, a position sensor is installed on the outside of the housing; the detection end of the position sensor is non-contactly engaged with the end of the screw shaft to monitor the rotation angle of the screw shaft in real time; a displacement sensor is fixedly connected to the end of the push-pull screw, the detection rod of the displacement sensor is parallel to the axial movement direction of the push-pull screw, and is used to detect the axial movement distance of the push-pull screw; the signal output ends of the position sensor and the displacement sensor are both electrically connected to the ECU of the diesel engine through wires.

[0020] During operation, the diesel engine's ECU (Electronic Control Unit) receives real-time angle signals from the helical shaft from the position sensor and movement distance signals from the push-pull screw from the displacement sensor. Using an internally preset algorithm model, it calculates and analyzes the correspondence between the helical shaft angle and injection timing, as well as the transmission ratio between the push-pull screw displacement and the helical shaft rotation angle, to determine in real time whether the current injection timing is optimal. When a deviation is detected between the actual injection timing and the theoretical optimal value, the ECU immediately sends an adjustment command to the drive unit. The drive unit then rotates the push-pull screw via a reducer, thereby correcting the helical shaft angle. If the angle or displacement signals detected by the sensors exhibit abnormal fluctuations, exceed the normal operating range, or do not match the control commands issued by the ECU, the ECU determines that the adjustment device may be stuck, experiencing transmission failure, or sensor malfunction. It then issues a fault warning signal to the driver via the instrument panel and stores the fault code for subsequent maintenance. This solution, through dual detection and feedback from position and displacement sensors, not only achieves real-time closed-loop control of the fuel injection timing adjustment process, improving adjustment accuracy and response speed, but also promptly detects abnormal conditions during device operation, providing reliable data support for diesel engine performance optimization and fault diagnosis, and further enhancing the safety and reliability of diesel engine operation.

[0021] Preferably, the ECU of the diesel engine has a preset algorithm model; the algorithm model is a multi-parameter coupled control algorithm built based on the mapping relationship between the diesel engine operating condition parameters (such as speed, load, water temperature, intake pressure, etc.) and the optimal value of injection timing, combined with the linear conversion formula between the screw shaft rotation angle and the injection timing, and the transmission ratio model of the push-pull screw displacement and the screw shaft rotation angle.

[0022] The algorithm model includes the following execution steps:

[0023] Step 1: First, determine the theoretically optimal injection timing angle under the current operating condition by querying the preset working condition-injection timing MAP (i.e., a three-dimensional data table);

[0024] Step 2: Then, based on the actual angle of the screw shaft fed back in real time by the position sensor, calculate the deviation between the actual fuel injection timing and the theoretical optimal value;

[0025] Step 3: Next, call the transmission ratio model to convert the angular deviation into the required target displacement of the push-pull screw;

[0026] Step 4: Finally, the target displacement is compared with the actual displacement detected by the displacement sensor. The control signal of the drive device is generated by the PID (proportional-integral-derivative) adjustment algorithm to drive the push-pull screw to move to the target position, thereby realizing precise closed-loop control of fuel injection timing.

[0027] During operation, when the diesel engine is running, the ECU first collects key operating parameters such as engine speed, load, coolant temperature, and intake air pressure in real time, and inputs these parameters into a preset operating condition-injection timing MAP to quickly retrieve the theoretically optimal injection timing angle for the current operating condition. Subsequently, the ECU receives the actual rotation angle signal of the screw shaft from the position sensor, and calculates the current actual injection timing angle using a preset linear conversion formula between the screw shaft rotation angle and injection timing. This actual injection timing angle is then compared with the theoretically optimal injection timing angle to obtain the deviation. Next, the ECU uses the transmission ratio model of the push-pull screw displacement and the screw shaft rotation angle to convert the calculated angle deviation into the target displacement that the push-pull screw needs to move. Afterwards, the displacement sensor feeds back the detected actual displacement of the push-pull screw to the ECU, which calculates the difference between the target displacement and the actual displacement, and inputs the resulting displacement deviation signal into the PID control algorithm module. The PID control algorithm dynamically generates a control signal for the drive unit based on the proportional, integral, and derivative characteristics of the displacement deviation. This control signal precisely adjusts the output speed and direction of the drive unit, thereby controlling the push-pull screw to rotate and move to the target displacement position. The movement of the push-pull screw drives the screw shaft to rotate to the target angle via a screw drive, thus adjusting the actual fuel injection timing to the theoretical optimal value, forming a complete closed-loop control process. This multi-parameter coupled control algorithm can quickly and accurately adjust the fuel injection timing according to real-time changes in diesel engine operating conditions, ensuring that the diesel engine maintains optimal combustion efficiency and power performance under different speeds and loads, effectively reducing fuel consumption and emissions.

[0028] Preferably, the algorithm model also integrates a sensor signal filtering module and an outlier detection module; the sensor signal filtering module is used to eliminate high-frequency noise interference in the detection signal; the outlier detection module assists in the realization of fault diagnosis function by comparing the correlation between the position sensor and displacement sensor signals (whether the deviation between the theoretical calculation value based on the transmission ratio and the actual detection value is within the threshold range).

[0029] During operation, the sensor signal filtering module performs low-pass filtering on the raw signals collected by the position and displacement sensors, filtering out high-frequency noise caused by electromagnetic interference, mechanical vibration, and other factors, retaining the true and valid detection signals. This ensures that the angle and displacement data received by the ECU are accurate and reliable, avoiding misjudgments or abnormal adjustment commands caused by noise signals. The outlier judgment module calculates the theoretical correspondence between the helical shaft angle detected by the position sensor and the push-pull screw displacement detected by the displacement sensor in real time (based on a preset transmission ratio model). It compares the theoretically calculated value with the actual detected value. If the deviation exceeds the set threshold range and the duration exceeds the preset time, it determines that there may be problems such as sensor failure, transmission component abnormality, or signal transmission interruption. It then triggers the ECU's fault diagnosis process, further combining historical data and current operating conditions to comprehensively determine the fault type and execute the corresponding fault handling mechanism, such as limiting diesel engine power output, switching to backup control strategy, or issuing a more specific fault code, providing maintenance personnel with accurate fault location information. This solution further enhances the anti-interference capability and fault diagnosis accuracy of the entire regulation system by preprocessing and verifying the correlation of sensor signals, ensuring stable and reliable operation under complex working conditions and providing dual protection for the safe operation of the diesel engine.

[0030] Preferably, the algorithm model further includes an adaptive learning module and a working condition prediction and compensation module. The adaptive learning module records the actual injection timing adjustment effect of the diesel engine under different working conditions (such as feedback data on combustion efficiency, emission indicators, and power output) over a long period of time, compares and analyzes it with the theoretical optimal value, and automatically corrects the mapping relationship in the working condition-injection timing MAP and the parameters of the PID control algorithm. This allows the algorithm model to dynamically optimize the control strategy based on long-term factors such as the aging degree of the diesel engine and changes in fuel quality, improving the adaptability and durability of the adjustment accuracy. The working condition prediction and compensation module, based on historical operating data and the current trend of operating condition parameter changes (such as the dynamic change rate of speed and load), identifies abrupt changes in the working condition (such as rapid acceleration and deceleration) in advance and generates compensation amounts in advance before the ECU issues adjustment commands. This shortens the response lag time of the adjustment system, avoids excessive instantaneous injection timing deviations caused by rapid changes in working conditions, and ensures that the diesel engine can maintain stable combustion performance and emission levels under dynamic working conditions.

[0031] During operation, the adaptive learning module continuously monitors the actual operating data of the diesel engine under various operating conditions, including combustion efficiency (indirectly obtained through in-cylinder pressure sensors or exhaust temperature), emission indicators (such as nitrogen oxides and particulate matter concentrations), and power output parameters (such as torque and power). This actual feedback data is compared with the expected effect corresponding to the theoretically optimal injection timing in the algorithm model. If, under a specific operating condition, the actual combustion efficiency is lower than expected or the emission indicators exceed the standard range, the adaptive learning module determines that there is a deviation in the mapping relationship of that operating condition point in the current operating condition-injection timing MAP. At this time, the module automatically fine-tunes the theoretically optimal injection timing angle of the corresponding area in the MAP based on the degree of deviation, and simultaneously corrects parameters such as the proportional coefficient, integral time, and derivative time in the PID control algorithm, so that subsequent adjustments better match the current actual performance state of the diesel engine. Through long-term learning and correction, the algorithm model can gradually adapt to performance changes in the diesel engine caused by factors such as component aging, carbon deposit formation, and fuel quality differences, consistently maintaining high adjustment accuracy and control effect.

[0032] The operating condition prediction and compensation module analyzes the recent trends and rates of change in diesel engine operating parameters such as speed and load to establish an operating condition abrupt change identification model. When a rapid increase (e.g., rapid acceleration) or decrease (e.g., rapid deceleration) in speed or load is detected, and the rate of change exceeds a preset threshold, the module determines that an operating condition abrupt change is about to occur. Based on the adjustment process and results of similar operating condition abrupt changes in historical data, the operating condition prediction and compensation module calculates in advance the compensation amount required to offset the response lag of the adjustment system, and adds this compensation amount to the theoretical adjustment command obtained by the ECU from the MAP chart based on the current operating conditions. This allows the drive unit to act in advance, pre-adjusting the displacement of the push-pull screw and the rotation angle of the screw shaft. For example, under rapid acceleration conditions, the module predicts that the load will increase rapidly and that earlier injection timing is required to obtain greater explosive power. Therefore, before the ECU officially issues the adjustment command, the auger shaft is pre-driven to rotate a certain angle in the direction of early injection, thereby effectively shortening the time interval from the change in operating conditions to the adjustment of the injection timing. This avoids the problem of instantaneous combustion deterioration or insufficient power during dynamic transition, ensuring that the diesel engine can maintain optimal combustion efficiency, power performance and emission levels throughout the entire operating cycle, whether under steady-state or dynamic conditions.

[0033] The beneficial effects of this invention are as follows:

[0034] 1. This invention employs a combined structure of helical drive and spline guidance, utilizing the design characteristic that the helix angle is greater than the friction angle to ensure the efficiency of force transmission and the reversibility of the motion direction during the transmission process. This efficiently converts the rotational motion output by the drive device into the precise rotation of the helical shaft. At the same time, the helical drive cannot be reversed, thus achieving self-locking. Forward drive is not affected by self-locking, effectively avoiding the adjustment lag and insufficient precision problems caused by self-locking in traditional adjustment devices. The overall structure is compact, and the components work together stably and reliably, providing a technical solution for the dynamic adjustment of diesel engine injection timing that is responsive and precise.

[0035] 2. This invention sets the helix angle of the threaded connection between the helical sleeve and the helical shaft to be 5-10° greater than the friction angle. This design, while ensuring the helical drive can achieve reverse motion, further improves transmission efficiency and power transmission reliability. Compared to designs with an angle only slightly greater than the friction angle, the 5-10° difference effectively reduces the adverse effects of machining errors, changes in lubrication conditions, or instantaneous load fluctuations on the reverse motion of the helical drive. This ensures that under various operating conditions, the axial movement of the helical sleeve can be stably and accurately converted into the rotation of the helical shaft, avoiding transmission jamming or response delays. Simultaneously, this angle difference design also reduces friction and wear between the helical surfaces to a certain extent, extending the service life of the helical drive pair, thereby ensuring the long-term stability and adjustment accuracy of the fuel injection timing adjustment device.

[0036] 3. In this invention, lubricating oil is injected into the housing through the oil injection channel on the housing. During the axial movement of the spiral sleeve, the internal spaces of the housing at both ends of the spiral sleeve and the internal space of the spiral sleeve itself are constantly changing, creating a pressure difference. This pressure difference drives the lubricating oil through the oil passages on the fixed cover into the spiral sleeve. These oil passages evenly guide the lubricating oil to the threaded mating surfaces between the spiral sleeve and the spiral shaft, and between the clearance-eliminating sleeve and the spiral shaft, forming a continuous and effective lubricating film. The evenly distributed oil passage design ensures that each lubrication point receives sufficient lubricating oil, avoiding dry friction or increased wear due to insufficient lubrication in certain areas. Simultaneously, excess lubricating oil can carry away the heat generated by friction, providing a cooling effect and further improving the stability and durability of the device. Attached Figure Description

[0037] The invention will now be further described with reference to the accompanying drawings.

[0038] Figure 1 This is a schematic diagram of the overall structure of the fuel injection timing adjustment device of the present invention;

[0039] Figure 2 This is a schematic diagram of the internal structure of the fuel injection timing adjustment device of the present invention from a first-view perspective;

[0040] Figure 3 This is a schematic diagram of the internal structure of the fuel injection timing adjustment device of the present invention from a second perspective;

[0041] Figure 4 This is a schematic diagram of the internal structure of the fuel injection timing adjustment device of the present invention from a third-person perspective;

[0042] Figure 5 This is a schematic diagram of the connection between the spiral shaft and the spiral sleeve in the first view of the present invention;

[0043] Figure 6 This is a schematic diagram of the connection between the helical shaft and the helical sleeve in the second view of the present invention;

[0044] Figure 7 This is a schematic diagram of the connection between the spiral sleeve and the gap-eliminating sleeve in this invention;

[0045] Figure 8 This is a schematic diagram of the axial limiting snap ring in this invention;

[0046] Figure 9 This is a schematic diagram of the gap-eliminating sleeve in this invention;

[0047] In the diagram: 1. Housing; 2. Spiral shaft; 21. Tapered roller bearing; 22. Bearing cover; 3. Spiral sleeve; 31. Clearance elimination sleeve; 32. Axial limiting snap ring; 321. Snap-fit ​​structure; 4. Spline guide sleeve; 5. Fixing cover; 51. Oil passage hole; 6. Push-pull screw; 61. Thrust ball bearing; 62. Locking screw; 7. Threaded sleeve; 71. End cover. Detailed Implementation

[0048] To make the technical means, creative features, objectives, and effects of this invention easier to understand, the following description is provided in conjunction with the appendix. Figure 1 To be continued Figure 9 The invention will be further described below, along with specific implementation methods.

[0049] An electric fuel injection timing adjustment device includes a housing 1, a helical shaft 2, a tapered roller bearing 21, a bearing cover 22, a helical sleeve 3, a splined guide sleeve 4, a fixing cover 5, a push-pull screw 6, a threaded sleeve 7, and an end cover 71. The housing 1 has an internal cavity for accommodating the various components. The helical shaft 2 is arranged axially along the housing 1, and one end of the helical shaft 2 is rotatably connected to the housing 1 via the tapered roller bearing 21. The outer ring of the tapered roller bearing 21 abuts against the inner wall of one end of the housing 1, and the inner ring is fitted onto the helical shaft 2. The bearing cover 22 is fixed to the end of the housing 1 by bolts to axially limit the tapered roller bearing 21. The helical sleeve 3 is fitted onto the housing 1. Outside the helical shaft 2, and engaged with the helical shaft 2 by a thread with a helix angle greater than the friction angle; a spline guide sleeve 4 is fixedly connected to the outer wall of the helical sleeve 3; an axially extending guide groove is provided on the inner wall of the middle part of the housing 1; the spline guide sleeve 4 is slidably connected in the guide groove; a fixed cover 5 is fixedly connected to the end of the helical sleeve 3; one end of the push-pull screw 6 is rotatably connected to the fixed cover 5; the other end of the push-pull screw 6 extends to the outside of the housing 1; a threaded sleeve 7 is fitted onto the push-pull screw 6 and is threadedly connected to the push-pull screw 6; the threaded sleeve 7 is fixedly connected to the end cover 71; the end cover 71 is fixedly connected to the end face of the other end of the housing 1.

[0050] During operation, the threaded sleeve 7 remains stationary along with the end cover 71. When the reducer of the drive device drives the push-pull screw 6 to rotate, due to the threaded engagement between the push-pull screw 6 and the threaded sleeve 7, the push-pull screw 6 will move linearly along its own axis. The movement of the push-pull screw 6 causes the fixed cover 5, which is rotatably connected to it, to move synchronously. The fixed cover 5 then pushes the spiral sleeve 3 to move axially. Because the spline guide sleeve 4 is slidably connected to the guide groove on the housing 1, the rotational freedom of the spiral sleeve 3 is restricted, so that the spiral sleeve 3 can only perform axial translation. During the axial movement, the spiral sleeve 3, through the helical transmission between itself and the spiral shaft 2, and the helix angle of the helical transmission is greater than the friction angle, ensures that the axial thrust can be converted into circumferential rotation, ensuring that the reverse motion of the helical transmission can be realized, thereby driving the spiral shaft 2 to rotate. The rotation of the screw shaft 2 is ultimately transmitted to the fuel injection system of the diesel engine through the fixed connection of the camshaft at the end, thereby achieving precise adjustment of the fuel injection timing. Since the camshaft and the intake and exhaust valves of the fuel injection system cooperate with each other, the start and closing times of each valve can be adjusted by adjusting the camshaft angle, thereby adjusting the advance angle and keeping the diesel engine in the best condition.

[0051] This solution employs a combination of helical drive and spline guidance, utilizing the design characteristic that the helix angle is greater than the friction angle to ensure efficient force transmission and reversibility of motion direction during the transmission process. This efficiently converts the rotational motion output by the drive unit into precise rotation of the helical shaft 2. Simultaneously, the helical drive cannot reverse, thus achieving self-locking. Forward drive is unaffected by self-locking, effectively avoiding the adjustment lag and insufficient precision problems caused by self-locking in traditional adjustment devices. The overall structure is compact, and the components work together stably and reliably, providing a rapid-response and precise control solution for the dynamic adjustment of diesel engine injection timing.

[0052] A gap-eliminating sleeve 31 is provided at one end of the spiral sleeve 3; the gap-eliminating sleeve 31 is fitted on the outside of the spiral shaft 2 and is engaged with the spiral shaft 2 by a thread with a helix angle greater than the friction angle; the gap-eliminating sleeve 31 and the spiral sleeve 3 are pressed together by an axial limiting snap ring 32.

[0053] During operation, the clearance-eliminating sleeve 31 and the spiral sleeve 3 are both fitted onto the spiral shaft 2, and both are engaged with the spiral shaft 2 through threads with a helix angle greater than the friction angle. When the spiral sleeve 3 moves axially under the push-pull screw 6, the clearance-eliminating sleeve 31 remains in a tight-fitting state with the spiral sleeve 3 under the clamping force of the axial limiting spring 32. This clamping relationship effectively eliminates the axial clearance and spiral transmission clearance between the spiral sleeve 3 and the spiral shaft 2 caused by machining and assembly errors, avoiding the problem of lag in the rotation of the spiral shaft 2 or a decrease in adjustment accuracy due to the existence of clearance during transmission, further improving the accuracy and stability of fuel injection timing adjustment. After a period of use and wear, the new clearance caused by wear can be compensated by replacing it with a thicker axial limiting spring 32, thereby extending the service life of the device and maintaining long-term adjustment accuracy.

[0054] like Figure 8 As shown, both ends of the axial limiting snap ring 32 are provided with snap-fit ​​structures 321; the snap-fit ​​structure 321 is a structure formed by the outer arc length of the axial limiting snap ring 32 being greater than the inner arc length and protruding inward; the outer arc diameter of the axial limiting snap ring 32 is smaller than the outer diameter of the spiral sleeve 3.

[0055] The outer diameter of the axial limiting spring 32 is smaller than the outer diameter of the spiral sleeve 3, ensuring that the overall structure of the axial limiting spring 32 does not protrude from the outer surface of the spiral sleeve 3. This prevents interference with the inner wall of the housing 1 or other components during the axial movement of the spiral sleeve 3, ensuring smooth operation of the device. Furthermore, by providing latching structures 321 at both ends of the axial limiting spring 32, convenient installation and removal of the axial limiting spring 32 can be achieved by opening the clamps to support the latching structures 321, ensuring no interference. This greatly simplifies the maintenance process and reduces the time and labor costs of daily maintenance. Simultaneously, the design of the latching structures 321 ensures that the axial limiting spring 32 maintains stable radial tension after installation, ensuring a continuous and reliable clamping effect on the gap-eliminating sleeve 31 and preventing the risk of gap-eliminating function failure due to loosening of the axial limiting spring 32.

[0056] The helix angle of the mating thread between the spiral sleeve 3 and the spiral shaft 2 is greater than the friction angle by 5-10°.

[0057] During operation, the helix angle of the threaded connection between the helical sleeve 3 and the helical shaft 2 is set to be 5-10° greater than the friction angle. This design, while ensuring the helical drive can achieve reverse motion, further improves transmission efficiency and power transmission reliability. Compared to a design with an angle only slightly greater than the friction angle, the 5-10° difference effectively reduces the adverse effects of machining errors, changes in lubrication conditions, or instantaneous load fluctuations on the reverse motion of the helical drive. This ensures that under various operating conditions, the axial movement of the helical sleeve 3 can be stably and accurately converted into the rotation of the helical shaft 2, avoiding transmission jamming or response delay. Simultaneously, this angle difference design also reduces friction and wear between the helical surfaces to a certain extent, extending the service life of the helical drive pair, thereby ensuring the long-term stability and adjustment accuracy of the fuel injection timing adjustment device.

[0058] like Figures 2 to 4 As shown, a mounting hole is provided in the middle of the fixed cover 5, and a thrust ball bearing 61 is provided on each side of the fixed cover 5; after the locking screw 62 passes through the thrust ball bearing 61 and the fixed cover 5, it is locked to the end of the push-pull screw 6.

[0059] During operation, the thrust ball bearings 61 on both sides of the fixed cover 5 are located at the two ends of the mounting hole. After the locking screw 62 locks the end of the push-pull screw 6 to the fixed cover 5, the inner ring of the thrust ball bearing 61 rotates synchronously with the push-pull screw 6, while the outer ring remains relatively stationary with the fixed cover 5. This structural design transforms the rotational connection between the push-pull screw 6 and the fixed cover 5 into the rolling friction of the thrust ball bearing 61, significantly reducing the frictional resistance and wear between the two. This ensures that the push-pull screw 6 can flexibly drive the fixed cover 5 to move axially during rotation, avoiding motion jamming or component overheating caused by direct contact friction. At the same time, the thrust ball bearing 61 can effectively withstand the bidirectional axial load generated by the push-pull screw 6 during axial movement, ensuring stable and reliable thrust transmission between the fixed cover 5 and the screw sleeve 3, further improving the smoothness of the entire adjustment device's movement and its service life.

[0060] like Figures 5 to 6 As shown, multiple oil passage holes 51 are evenly spaced along the circumference on the fixed cover 5 at positions corresponding to the inside of the spiral sleeve 3; the diameter of the oil passage holes 51 is 2-4mm, and the inner wall of the oil passage holes 51 is provided with a rounded corner transition structure.

[0061] During operation, lubricating oil is injected into the housing 1 through the oil injection channel. As the spiral sleeve 3 moves axially, the internal space of the housing 1 at both ends of the spiral sleeve 3 and the internal space of the spiral sleeve 3 are constantly changing, creating a pressure difference. This pressure difference drives the lubricating oil through the oil passage holes 51 on the fixed cover 5 into the spiral sleeve 3. These oil passage holes 51 can evenly guide the lubricating oil to the threaded mating surfaces between the spiral sleeve 3 and the spiral shaft 2, and between the clearance elimination sleeve 31 and the spiral shaft 2, forming a continuous and effective lubricating film. The evenly distributed oil passage hole 51 design ensures that each lubrication point receives sufficient lubricating oil, avoiding dry friction or increased wear caused by insufficient lubrication in certain areas. At the same time, excess lubricating oil can also carry away the heat generated by friction, playing a cooling role and further improving the stability and durability of the device.

[0062] The diameter of the oil passage hole 51 is 2-4mm, and the inner wall of the oil passage hole 51 is provided with a rounded transition structure. The diameter of 2-4mm ensures that there is enough lubricating oil to enter the spiral sleeve 3 through the oil passage hole 51 to meet the lubrication requirements of the threaded mating surface, while avoiding excessive lubricating oil loss or insufficient pressure difference due to an excessively large diameter, which would affect the lubrication effect. The rounded transition structure of the inner wall of the oil passage hole 51 can eliminate stress concentration at the orifice, preventing cracks or damage to the edge of the oil passage hole 51 due to stress concentration during long-term use. At the same time, it can also reduce the resistance of lubricating oil during the flow process, allowing the lubricating oil to enter the lubrication area more smoothly, further optimizing the lubrication effect and ensuring the long-term stable operation of the device.

[0063] A position sensor is installed on the outside of the housing 1; the detection end of the position sensor is non-contactly engaged with the end of the screw shaft 2 to monitor the rotation angle of the screw shaft 2 in real time; a displacement sensor is fixedly connected to the end of the push-pull screw 6, and the detection rod of the displacement sensor is parallel to the axial movement direction of the push-pull screw 6 to detect the axial movement distance of the push-pull screw 6; the signal output ends of both the position sensor and the displacement sensor are electrically connected to the ECU of the diesel engine through wires.

[0064] During operation, the diesel engine's ECU (Electronic Control Unit) receives real-time angle signals from the position sensor and movement distance signals from the displacement sensor for the push-pull screw 6. Using an internally preset algorithm model, it calculates and analyzes the correspondence between the angle of the screw shaft 2 and the injection timing, as well as the transmission ratio between the displacement of the push-pull screw 6 and the rotation angle of the screw shaft 2, to determine in real time whether the current injection timing is optimal. When a deviation is detected between the actual injection timing and the theoretical optimal value, the ECU immediately sends an adjustment command to the drive unit. The drive unit then rotates the push-pull screw 6 via a reducer, thereby correcting the angle of the screw shaft 2. If the angle or displacement signals detected by the sensors exhibit abnormal fluctuations, exceed the normal operating range, or do not match the control commands issued by the ECU, the ECU determines that the adjustment device may be stuck, experiencing transmission failure, or sensor malfunction. It then issues a fault warning signal to the driver via the instrument panel and stores the fault code for subsequent maintenance. This solution, through dual detection and feedback from position and displacement sensors, not only achieves real-time closed-loop control of the fuel injection timing adjustment process, improving adjustment accuracy and response speed, but also promptly detects abnormal conditions during device operation, providing reliable data support for diesel engine performance optimization and fault diagnosis, and further enhancing the safety and reliability of diesel engine operation.

[0065] The ECU of the diesel engine has a preset algorithm model. The algorithm model is a multi-parameter coupled control algorithm built on the mapping relationship between the diesel engine operating condition parameters (such as speed, load, water temperature, intake pressure, etc.) and the optimal value of injection timing, combined with the linear conversion formula between the rotation angle of the screw shaft 2 and the injection timing, and the transmission ratio model of the displacement of the push-pull screw 6 and the rotation angle of the screw shaft 2.

[0066] The algorithm model includes the following execution steps:

[0067] Step 1: First, determine the theoretically optimal injection timing angle under the current operating condition by querying the preset working condition-injection timing MAP (i.e., a three-dimensional data table);

[0068] Step 2: Then, based on the actual angle of the spiral shaft 2 fed back by the position sensor in real time, calculate the deviation between the actual fuel injection timing and the theoretical optimal value;

[0069] Step 3: Next, call the transmission ratio model to convert the angular deviation into the required target displacement of the push-pull screw 6;

[0070] Step 4: Finally, the target displacement is compared with the actual displacement detected by the displacement sensor. The control signal of the drive device is generated by the PID (proportional-integral-derivative) adjustment algorithm to drive the push-pull screw 6 to move to the target position, thereby realizing precise closed-loop control of the fuel injection timing.

[0071] During operation, when the diesel engine is running, the ECU first collects key operating parameters such as engine speed, load, coolant temperature, and intake air pressure in real time, and inputs these parameters into a preset operating condition-injection timing MAP to quickly retrieve the theoretically optimal injection timing angle for the current operating condition. Then, the ECU receives the actual rotation angle signal of the screw shaft 2 from the position sensor, and calculates the current actual injection timing angle using a preset linear conversion formula between the screw shaft 2 rotation angle and injection timing. This actual injection timing angle is then compared with the theoretically optimal injection timing angle to obtain the deviation. Next, the ECU uses the transmission ratio model of the displacement of the push-pull screw 6 and the rotation angle of the screw shaft 2 to convert the calculated angle deviation into the target displacement that the push-pull screw 6 needs to move. Afterwards, the displacement sensor feeds back the detected actual displacement of the push-pull screw 6 to the ECU. The ECU performs a difference calculation between the target displacement and the actual displacement, and inputs the resulting displacement deviation signal into the PID control algorithm module. The PID control algorithm dynamically generates a control signal for the drive unit based on the proportional, integral, and derivative characteristics of the displacement deviation. This control signal precisely adjusts the output speed and direction of the drive unit, thereby controlling the push-pull screw 6 to rotate and move to the target displacement position. The movement of the push-pull screw 6 drives the screw shaft 2 to rotate to the target angle through the screw drive, thus adjusting the actual fuel injection timing to the theoretical optimal value, forming a complete closed-loop control process. This multi-parameter coupled control algorithm can quickly and accurately adjust the fuel injection timing according to the real-time changes in the diesel engine's operating conditions, ensuring that the diesel engine maintains optimal combustion efficiency and power performance under different speeds, loads, and other operating conditions, effectively reducing fuel consumption and emissions.

[0072] The algorithm model also integrates a sensor signal filtering module and an outlier detection module. The sensor signal filtering module is used to eliminate high-frequency noise interference in the detection signal. The outlier detection module assists in the realization of fault diagnosis function by comparing the correlation between the position sensor and displacement sensor signals (whether the deviation between the theoretical calculation value based on the transmission ratio and the actual detection value is within the threshold range).

[0073] During operation, the sensor signal filtering module performs low-pass filtering on the raw signals collected by the position and displacement sensors, filtering out high-frequency noise caused by electromagnetic interference, mechanical vibration, and other factors, retaining the true and valid detection signals, ensuring that the angle and displacement data received by the ECU are accurate and reliable, and avoiding misjudgments or abnormal adjustment commands caused by noise signals. The outlier judgment module calculates in real time the theoretical correspondence between the angle of the screw shaft 2 detected by the position sensor and the displacement of the push-pull screw 6 detected by the displacement sensor (based on a preset transmission ratio model), and compares the theoretically calculated value with the actual detected value. If the deviation between the two exceeds the set threshold range and the duration exceeds the preset time, it is determined that there may be problems such as sensor failure, transmission component abnormality, or signal transmission interruption. Then, the ECU's fault diagnosis process is triggered, and the fault type is further determined by combining historical data and current operating conditions. The corresponding fault handling mechanism is executed, such as limiting the diesel engine power output, switching to the backup control strategy, or issuing a more specific fault code, providing maintenance personnel with accurate fault location basis. This solution further enhances the anti-interference capability and fault diagnosis accuracy of the entire regulation system by preprocessing and verifying the correlation of sensor signals, ensuring stable and reliable operation under complex working conditions and providing dual protection for the safe operation of the diesel engine.

[0074] The algorithm model also includes an adaptive learning module and a condition prediction and compensation module. The adaptive learning module records the actual injection timing adjustment effect of the diesel engine under different operating conditions (such as feedback data on combustion efficiency, emission indicators, and power output) over a long period of time, compares and analyzes it with the theoretical optimal value, and automatically corrects the mapping relationship in the operating condition-injection timing MAP and the parameters of the PID control algorithm. This allows the algorithm model to dynamically optimize the control strategy based on long-term factors such as the aging degree of the diesel engine and changes in fuel quality, improving the adaptability and durability of the adjustment accuracy. The condition prediction and compensation module, based on historical operating data and the current operating condition parameter change trend (such as the dynamic change rate of speed and load), identifies abrupt changes in operating conditions (such as rapid acceleration and deceleration) in advance and generates compensation amounts in advance before the ECU issues adjustment commands. This shortens the response lag time of the adjustment system and avoids excessive instantaneous injection timing deviations caused by rapid changes in operating conditions, ensuring that the diesel engine can maintain stable combustion performance and emission levels under dynamic operating conditions.

[0075] During operation, the adaptive learning module continuously monitors the actual operating data of the diesel engine under various operating conditions, including combustion efficiency (indirectly obtained through in-cylinder pressure sensors or exhaust temperature), emission indicators (such as nitrogen oxides and particulate matter concentrations), and power output parameters (such as torque and power). This actual feedback data is compared with the expected effect corresponding to the theoretically optimal injection timing in the algorithm model. If, under a specific operating condition, the actual combustion efficiency is lower than expected or the emission indicators exceed the standard range, the adaptive learning module determines that there is a deviation in the mapping relationship of that operating condition point in the current operating condition-injection timing MAP. At this time, the module automatically fine-tunes the theoretically optimal injection timing angle of the corresponding area in the MAP based on the degree of deviation, and simultaneously corrects parameters such as the proportional coefficient, integral time, and derivative time in the PID control algorithm, so that subsequent adjustments better match the current actual performance state of the diesel engine. Through long-term learning and correction, the algorithm model can gradually adapt to performance changes in the diesel engine caused by factors such as component aging, carbon deposit formation, and fuel quality differences, consistently maintaining high adjustment accuracy and control effect.

[0076] The operating condition prediction and compensation module analyzes the recent trends and rates of change in operating parameters such as engine speed and load to establish an operating condition abrupt change identification model. When a rapid increase (e.g., rapid acceleration) or decrease (e.g., rapid deceleration) in speed or load is detected, and the rate of change exceeds a preset threshold, the module determines that an operating condition abrupt change is about to occur. Based on the adjustment process and results of similar operating condition abrupt changes in historical data, the operating condition prediction and compensation module calculates in advance the compensation amount required to offset the response lag of the adjustment system, and adds this compensation amount to the theoretical adjustment command obtained by the ECU from the MAP chart based on the current operating conditions. This allows the drive unit to act in advance, pre-adjusting the displacement of the push-pull screw 6 and the rotation angle of the screw shaft 2. For example, under rapid acceleration conditions, the module predicts that the load will increase rapidly and that earlier injection timing is required to obtain greater explosive power. Therefore, before the ECU officially issues the adjustment command, it pre-drives the screw shaft 2 to rotate a certain angle in the direction of earlier injection, thereby effectively shortening the time interval from the change in operating conditions to the adjustment of the injection timing. This avoids the problem of instantaneous combustion deterioration or insufficient power during dynamic transition, ensuring that the diesel engine can maintain optimal combustion efficiency, power performance and emission levels throughout the entire operating cycle, whether under steady-state or dynamic conditions.

[0077] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. An electric fuel injection timing adjustment device, comprising a housing (1), characterized in that: It also includes a helical shaft (2), a tapered roller bearing (21), a bearing cover (22), a helical sleeve (3), a spline guide sleeve (4), a fixing cover (5), a push-pull screw (6), a threaded sleeve (7), and an end cover (71); the housing (1) has a cavity inside for accommodating the components; the helical shaft (2) is arranged along the axial direction of the housing (1), and one end of the helical shaft (2) is rotatably connected to the housing (1) through the tapered roller bearing (21); the outer ring of the tapered roller bearing (21) abuts against the inner wall of one end of the housing (1), and the inner ring of the tapered roller bearing (21) is fitted on the helical shaft (2); the bearing cover (22) is fixed to the end of the housing (1) by bolts to limit the axial movement of the tapered roller bearing (21); the helical sleeve (3) is fitted on the helical shaft (21). The outer side of the spiral sleeve (3) is connected to the spiral shaft (2) by a thread with a helix angle greater than the friction angle; the spline guide sleeve (4) is fixedly connected to the outer wall of the spiral sleeve (3); an axially extending guide groove is provided on the inner wall of the middle part of the housing (1); the spline guide sleeve (4) is slidably connected in the guide groove; the fixed cover (5) is fixedly connected to the end of the spiral sleeve (3); one end of the push-pull screw (6) is rotatably connected to the fixed cover (5); the other end of the push-pull screw (6) extends to the outside of the housing (1); the threaded sleeve (7) is fitted on the push-pull screw (6) and is threadedly connected to the push-pull screw (6); the threaded sleeve (7) is fixedly connected to the end cover (71); the end cover (71) is fixedly connected to the end face of the other end of the housing (1).

2. The electric fuel injection timing adjustment device according to claim 1, characterized in that: One end of the spiral sleeve (3) is provided with a gap elimination sleeve (31); the gap elimination sleeve (31) is fitted on the outside of the spiral shaft (2) and is engaged with the spiral shaft (2) by a thread with a helix angle greater than the friction angle; the gap elimination sleeve (31) and the spiral sleeve (3) are pressed together by an axial limiting snap ring (32).

3. The electric fuel injection timing adjustment device according to claim 2, characterized in that: Both ends of the axial limiting snap ring (32) are provided with snap-fit ​​structures (321); the snap-fit ​​structure (321) is a structure formed by the outer arc length of the axial limiting snap ring (32) being greater than the inner arc length and protruding inward; the outer arc diameter of the axial limiting snap ring (32) is smaller than the outer diameter of the spiral sleeve (3).

4. The electric fuel injection timing adjustment device according to claim 3, characterized in that: The helix angle of the mating thread between the spiral sleeve (3) and the spiral shaft (2) is greater than the friction angle by 5-10°.

5. The electric fuel injection timing adjustment device according to claim 1, characterized in that: The fixing cover (5) has an installation hole in the middle, and a thrust ball bearing (61) is provided on each side of the fixing cover (5); after the locking screw (62) passes through the thrust ball bearing (61) and the fixing cover (5), it is locked to the end of the push-pull screw (6).

6. The electric fuel injection timing adjustment device according to claim 5, characterized in that: The fixed cover (5) is provided with multiple oil passage holes (51) evenly spaced along the circumference at positions corresponding to the inside of the spiral sleeve (3); the diameter of the oil passage hole (51) is 2-4mm, and the inner wall of the oil passage hole (51) is provided with a rounded corner transition structure.

7. The electric fuel injection timing adjustment device according to claim 6, characterized in that: A position sensor is installed outside the housing (1); the detection end of the position sensor is non-contactly engaged with the end of the screw shaft (2) to monitor the rotation angle of the screw shaft (2) in real time; a displacement sensor is fixedly connected to the end of the push-pull screw (6), the detection rod of the displacement sensor is parallel to the axial movement direction of the push-pull screw (6) to detect the axial movement distance of the push-pull screw (6); the signal output ends of the position sensor and the displacement sensor are both electrically connected to the ECU of the diesel engine through wires.

Images