Starting device and method for starting internal combustion engine without external energy and matching with flexible support dynamometer

Abstract

The invention discloses a starting device and method for a flexible support dynamometer matched with an external-energy-free starting internal combustion engine, and belongs to the technical field of internal combustion engine testing. The starting device comprises a flexible support hydraulic dynamometer, a main shaft of the flexible support hydraulic dynamometer comprises a free end and a load end, and the load end is connected with a main shaft of a tested internal combustion engine; the free end is connected with the power input shaft through a jaw overrun clutch; the variable frequency motor is used as a power device to output rotating speed and torque, and the variable frequency motor stops working after the tested internal combustion engine is started; the device further comprises a rigid-flexible conversion assembly, a main shaft of the dynamometer does not swing through rigid supporting during starting, the diesel engine enters an idle speed after being started, and the dynamometer recovers to a flexible supporting state along with automatic separation of the jaw overrunning clutch. The diesel engine provided with the flexible support hydraulic dynamometer in an energy-free starting mode is smoothly started when a test bed is tested, transmission in the starting process is stable, and the automatic separation function of the starting device and the flexible support hydraulic dynamometer is achieved after the diesel engine is started.

Description

Technical Field

[0001] This invention belongs to the field of internal combustion engine testing technology, and relates to the use of external energy to simultaneously drive a flexible support hydraulic dynamometer and a diesel engine that starts without external energy to rotate together, thereby starting the diesel engine that starts without external energy. In particular, it relates to a starting device and method for using a flexible support hydraulic dynamometer test bench for internal combustion engines that start without external energy. Background Technology

[0002] An internal combustion engine that does not require external power to start refers to an internal combustion engine that does not rely on external power sources, air sources, or other equipment, such as a starter motor or a high-pressure air starter. It can start itself using only the diesel engine or the power of the operator, and has extremely high reliability and environmental adaptability.

[0003] A flexible support hydraulic dynamometer refers to a dynamometer whose main body (including stator, rotor, and housing) is supported on the outlet tank by flexible components (such as external arm torsion springs or leaf springs, and flexible support shafts). This support system allows the dynamometer body to swing freely around its axis to a limited extent. It features a relatively simple structure, relatively low manufacturing cost, only bears radial load, low foundation requirements, moderate dynamic response capability, wide measurement range, and high measurement accuracy.

[0004] In existing diesel engine starting technologies, external power sources are often used to drive the diesel engine or a dynamometer to start the vehicle. There are several methods, detailed below. The first method is to use the diesel engine's built-in starter motor to start the diesel engine. Since diesel engines do not have an external power source for starting, under certain constraints, it is not possible to add a starting solution. Therefore, the first method cannot be used to solve the problem of the diesel engine failing to start in this scenario.

[0005] The second method is to use the diesel engine's built-in air distributor to fill the cylinder with high-pressure air to start it. However, since diesel engines do not have an external power source for starting, under certain constraints, it is impossible to add a starting solution. Therefore, the second method cannot be used to solve the problem of the diesel engine failing to start in this scenario.

[0006] The third approach involves adding a gear at the connection between the flexible support hydraulic dynamometer and the diesel engine, and arranging a starter motor parallel to the dynamometer's main shaft. This uses gear transmission to drive the hydraulic dynamometer and diesel engine to start. In this solution, the axial position of the starting motor's driving gear is fixed, while the driven gear is a flexible support. During the starting process, gear meshing can result in skipped teeth and tooth knocking. This can cause minor damage to the gears, such as tooth surface scuffing, wear, pitting, and tooth root fracture. In severe cases, it can damage the flexible support hydraulic dynamometer and cause the diesel engine transmission to fail. Therefore, this third approach cannot solve the problem of the diesel engine failing to start in this scenario.

[0007] The fourth method involves an electric dynamometer test bench. The electric dynamometer is switched to motor mode, and the motor drives it to start. In this mode, the electric dynamometer is the drive and the diesel engine is the load. After starting, the electric dynamometer switches to generator mode, with the diesel engine as the drive and the electric dynamometer as the load. The electric dynamometer and the diesel engine can be converted into load and drive respectively. However, their rotational inertia cannot be converted into each other, which cannot meet the rotational inertia matching requirements. Due to issues such as technical solution upgrade matching, supporting facilities, cycle and cost, the current flexible support hydraulic dynamometer cannot be upgraded to an electric dynamometer. Therefore, the fourth method cannot be used to solve the problem of the diesel engine not starting in this scenario.

[0008] The fifth method involves connecting a rigid-supported electric dynamometer and a rigid-supported hydraulic dynamometer in series. The rigid-supported electric dynamometer is switched to motor mode, and the motor drives both the rigid-supported hydraulic dynamometer and the diesel engine to start the diesel engine. After starting, the electric dynamometer switches to generator mode. This solution also fails to meet the requirement of matching the rotational inertia of the mutual drive and load. However, both dynamometers are rigidly supported, and each dynamometer's main shaft experiences only minor eccentricity and axial angular displacement, ensuring concentricity. Therefore, the two dynamometers connected in series can be used as a single dynamometer. However, when the flexible-supported dynamometer operates, its main shaft swings with the four hinge supports, causing displacement in both the X and Y directions of its cross-section, as well as axial angular displacement. If the rigid-supported electric dynamometer is connected in series with the flexible-supported hydraulic dynamometer, a tipping moment will be generated between the two main shafts. This could damage the bearings of both dynamometers or even render both dynamometers unusable. Therefore, this solution cannot be directly used to solve the current diesel engine starting problem in this scenario.

[0009] Of the above options, Option 1 uses a cantilever beam configuration for both transmission gears, and Option 3 uses a flexible support for the driven gear. Both are prone to tooth skipping and impaction during gear meshing. Minor issues may include gear damage such as tooth surface scuffing, wear, pitting, and tooth root fracture; more serious issues could damage the flexible support bearings of the hydraulic dynamometer or cause diesel engine transmission failure. Options 4 and 5, because the dynamometer and diesel engine can convert between drive and load during startup and other tests, cannot convert their moment of inertia accordingly, thus failing to meet the matching requirements between moment of inertia drive and load.

[0010] Despite numerous starting methods and case studies, current technology cannot yet solve the problem of starting diesel engines without external power sources using flexible support hydraulic dynamometers. This issue urgently needs to be addressed in the field of diesel engine testing. Summary of the Invention

[0011] To address the aforementioned problems in the prior art, this invention proposes a starting device and method for starting an internal combustion engine without external power source, equipped with a flexible support dynamometer. Addressing the technical issues in the background art, a variable frequency motor is used as the power source. By setting the starting ramp time, speed, and dragging duration of the variable frequency motor, the intensity of mechanical vibration generated by the diesel engine during the starting process is effectively adjusted. Matching a jaw-type overrunning clutch transmission, automatic separation of the starting device and the flexible support hydraulic dynamometer is achieved, solving the problem of moment of inertia matching during drive and load switching between electric and hydroelectric series dynamometers. Simultaneously, a rigid-flexible conversion component is set to ensure the main shaft position of the hydraulic dynamometer is fixed during the starting process, eliminating the possibility of misalignment of the transmission shaft, generating overturning torque, and damaging the equipment and diesel engine. Furthermore, the diesel engine returns to a flexible support state during testing.

[0012] A starting device for starting an internal combustion engine without external power source and equipped with a flexible support dynamometer includes a flexible support hydraulic dynamometer, which includes a water outlet tank, a rotor, and a housing as a stator. The housing is located above the water outlet tank. The rotor rotates inside the housing via its main shaft. The main shaft includes a free end and a load end. The load end is connected to the main shaft of the internal combustion engine under test, and the free end is connected to the power input shaft via a dog clutch. As a power unit, the variable frequency motor outputs speed and torque that match the speed, torque and moment of inertia of the load. After the diesel engine under test starts, the variable frequency motor stops working. It also includes a rigid-flexible conversion component, which allows the connection between the outer shell and the water outlet tank to switch between flexible support and rigid support through a detachable structure. During startup, the rigid support prevents the dynamometer spindle from wobbling. After the diesel engine starts and enters idle speed, the jaw clutch automatically disengages, allowing the dynamometer to return to the flexible support state.

[0013] Furthermore, the variable frequency motor speed selection is as follows: obtain the driving speed n1 and maximum power Pmax of the internal combustion engine during the starting process, match the rated speed nm and rated power Pm of the variable frequency motor, reduce the speed of the variable frequency motor, increase the torque, add a reducer with a reduction ratio of i, and the motor speed must satisfy nm=n1*i and Pm≥Pmax.

[0014] Furthermore, the rotational inertia of the variable frequency motor is selected as follows: the rotational inertia of the drive and the load is set to 1:5, the rotational inertia of the tested internal combustion engine is J3, the rotational inertia of the flexible support hydraulic dynamometer is J2, and the rotational inertia of the variable frequency motor is J1. The rotational inertia matching relationship of the variable frequency motor is determined to be J1:(J2+J3)=1:5.

[0015] Furthermore, during the test, the diesel engine J3 was used as the drive and the flexible support hydraulic dynamometer J2 was used as the load. According to the principle of matching rotational inertia, the ratio of J3 to J2 was designed to be 1:5. By setting the starting and climbing time, speed, and dragging time of the variable frequency motor, the intensity of the mechanical vibration generated by the diesel engine during the starting process was adjusted.

[0016] Furthermore, the main shaft of the variable frequency motor is arranged horizontally and concentrically with the crankshaft of the internal combustion engine under test, and the load end of the main shaft of the flexible support hydraulic dynamometer is set coaxially with the crankshaft of the internal combustion engine under test.

[0017] Furthermore, the rigid-flexible conversion component includes a fixed plate and a connecting plate. The fixed plate is located at the lower part of both axial ends of the flexible support hydraulic dynamometer, and the connecting plate is fixed at the upper end of the outlet trough. The connecting plate and the fixed plate are detachably connected, and the flexible support and rigid support can be converted into each other through fixing and disassembly.

[0018] Furthermore, the overrunning jaw clutch is a one-way triangular overrunning jaw clutch, including a left overrunning jaw clutch and a right overrunning jaw clutch that are fitted together. The left overrunning jaw clutch is rigidly connected to the coupling flange at the free end. The coupling flange is connected to the free end by a flat key and is interference-fitted, transmitting speed and torque in both directions. The outer ring of the right-side jaw clutch is provided with an annular groove, and the inner ring is a spline structure inner hole. The inner hole is used in conjunction with the spline drive shaft. The right-side jaw clutch moves axially along the spline drive shaft to transmit speed and torque, and disengages after the dynamometer speed is greater than the variable frequency motor speed. The other end of the spline drive shaft is connected to the output shaft of the reducer via a flexible coupling, with the variable frequency motor serving as the input end of the reducer.

[0019] Furthermore, a rolling element is provided in the annular groove. The rolling element is located inside the manual shift fork. The manual shift fork has an H-shaped structure. There are two rolling elements symmetrically arranged on the inner side of the manual shift fork. The rolling elements are mounted on a support column and are rotatably connected. The support column is slidably connected to the manual shift fork. The lower end of the manual shift fork is hinged to a fixed bracket. When the manual shift fork is moved, the motor rotates and drives the rolling element to rotate in the annular groove of the right-side jaw clutch. The support can move up and down within the frame, so that the jaw clutch engages.

[0020] Furthermore, the load end is connected to the main shaft of the internal combustion engine under test via a universal joint, coupling, and connecting flange, and the entire device is fixed on the ground plate to form an integral skid-mounted structure.

[0021] The method for using a starting device with a flexible support dynamometer for starting an internal combustion engine without external power includes the following steps. The first step is to fix the fixed plate and the connecting plate in the rigid-flexible conversion component to complete the conversion of the hydraulic dynamometer from flexible support to rigid support, so that the main shaft of the hydraulic dynamometer does not swing during startup. The second step is to engage the overrunning clutch by moving the manual shift fork before starting, so as to effectively transmit power. The third step involves using a variable frequency motor to drive a hydraulic dynamometer in a rigid support state and a diesel engine that starts without power. When the driven speed reaches a certain speed, the diesel engine successfully starts under compression ignition, and the variable frequency motor stops working. The fourth step is that after the diesel engine starts and enters idle speed, the starting device automatically disengages due to the engagement characteristics of the jaw clutch. The fixed connection between the fixing plate and the connecting plate is removed, and the hydraulic dynamometer returns to a flexible support state.

[0022] Compared with the prior art, the starting device and method for starting an internal combustion engine without external power source and equipped with a flexible support dynamometer described in this application have the following advantages: (1) This application realizes the rotation of a diesel engine driven by a variable frequency motor with flexible support hydraulic dynamometer and without external power source. The diesel engine can start smoothly without external power source. The transmission is smooth during the starting process. After starting, the starting device and the flexible support hydraulic dynamometer are automatically separated. A rigid-flexible conversion component and a jaw clutch are set. At the same time, a variable frequency motor is used as the power input. During the starting process, the flexible support hydraulic dynamometer is in a rigid support state, so that the dynamometer main shaft does not swing. After the start is completed, it returns to the flexible support state, ensuring that the position of the dynamometer main shaft is fixed during the starting process, eliminating the possibility of misalignment of the transmission shaft, generating overturning torque, and damaging the equipment and diesel engine. The jaw clutch enables the starting device and the flexible support hydraulic dynamometer to be automatically separated. It solves the problem of matching the rotational inertia of electric and hydroelectric series dynamometers during drive and load conversion. At the same time, by setting the starting ramp time, speed, and dragging time of the variable frequency motor, the intensity of mechanical vibration generated by the diesel engine during the starting process is adjusted.

[0023] (2) The spline drive shaft of the starting device of this application is concentric with the crankshaft of the diesel engine, realizing the concentric transmission of speed and torque. On the one hand, it avoids the skipping and tooth-backing phenomenon that occurs in the two parallel gear transmission, and on the other hand, it eliminates the possibility of overturning torque caused by the two drive shafts being parallel but not concentric. Attached Figure Description

[0024] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the starting device for a flexible support dynamometer used in starting an internal combustion engine without external power source, as per this application. Figure 2 This is a frontal view of the structure after the rigid-flexible conversion component of this application is combined with the flexible support hydraulic dynamometer. Figure 3 This is a side view of the structure of the rigid-flexible conversion component and the flexible support hydraulic dynamometer of this application. Figure 4 This is a schematic diagram of the right-side overrunning clutch of this application; Figure 5 This is a schematic diagram of the manual pull fork structure of this application; Figure 6 This is a schematic diagram of the starting device for a flexible support dynamometer used in starting an internal combustion engine without external power source, as described in this application.

[0025] Explanation of reference numerals in the attached figures: 1. Flexible support hydraulic dynamometer; 101. Fixing plate; 102. Connecting plate; 103. Connecting bolt; 104. Flexible support rod; 105. Transmission arm; 106. Tension / compression sensor; 2. Right-side jaw clutch overrunning clutch; 21. Annular groove; 3. Bracket; 4. Plum blossom flexible coupling; 5. Reducer; 6. Rigid support frame; 7. Coupling flange; 8. Left-side jaw clutch overrunning clutch; 9. Manual shift fork; 91. Frame; 92. Support column; 93. Rolling element; 10. Spline drive shaft; 11. Bearing; 12. Variable frequency motor; 15. Water outlet tank; 20. Ground plate; 31. Universal joint; 32. Coupling; 33. Connecting flange; 35. Test internal combustion engine. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0027] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0028] In this application, common terms are explained as follows.

[0029] A jaw clutch is a device that transmits torque and power through the engagement and disengagement of "teeth." It achieves rigid and precise "connection" and "disconnection," and is used in fields with extremely high requirements for precision, torque, and reliability. It engages when the speed difference between the driving and driven components is very small (almost synchronous) or even when they are stationary. The jaw clutch mainly consists of a driving component, a driven component, and a control slip ring. When power transmission is needed, the slip ring is moved to force the rigid jaws on the driving and driven components to mesh, achieving unidirectional rigid connection and torque transmission. When the driven component's speed exceeds that of the driving component or a disengagement command is received, the slip ring moves to disengage the jaws, separating the two components and achieving unidirectional free overrunning. The "engagement" and "disengagement" of the teeth rigidly and precisely control the on / off state of power. The manual shift fork in this application serves the function of the control slip ring.

[0030] The flexible-support hydraulic dynamometer is a high-precision device used to measure the output power (torque and speed) of rotating power machinery such as engines and motors. Its key feature lies in the combination of "hydraulic dynamometer" and "flexible support." The flexible-support hydraulic dynamometer mainly consists of a rotor, a housing (stator), and a flexible support mechanism (containing a force sensor). During actual testing, the engine under test drives the rotor to rotate within a water-filled housing. The frictional resistance of the water on the rotor causes a counter-torque on the housing. This housing is suspended by the flexible support, allowing it to transfer all of the counter-torque to the high-precision force sensor. By measuring this torque value and the real-time speed, the engine's precise power can be directly calculated. In other words, it absorbs power through hydraulic loading and achieves high-precision dynamometer measurement using the counter-torque measurement principle.

[0031] The specific calculation formula is as follows: Power (P) = Torque (T) × Rotational speed (n) / 9550; P is the effective power of the engine, in kilowatts (kW); T is the torque measured by the flexible support hydraulic dynamometer, in Newton-meters (N•m); n is the rotational speed of the engine or dynamometer spindle, in revolutions per minute (r / min or RPM); 9550 is a comprehensive conversion constant derived from the conversion relationship between power units (1 kW = 1000 W), torque units (1 N·m), and speed units (1 r / min = 1 / 60 s⁻¹). 60000 / 2π ≈ 9550. By directly reading the engine's torque (T) and speed (n) under a certain operating condition using a flexible support hydraulic dynamometer, and substituting them into this formula, the precise power output P of the engine under that operating condition can be obtained immediately.

[0032] This type of flexible-support hydraulic dynamometer design has its own drawbacks in specific scenarios. The hydraulic dynamometer can only absorb power in one direction (converting it into heat energy), unlike an electric dynamometer which can reverse and output power to the tested diesel engine (reverse drag). This drawback is even more pronounced when matched with diesel engines that cannot be started by external power sources. In other words, diesel engines without external starting capabilities cannot be started on the flexible-support hydraulic dynamometer test bench, making subsequent testing impossible.

[0033] like Figure 1-6 As shown, a starting device for starting an internal combustion engine without external power source and equipped with a flexible support dynamometer includes a flexible support hydraulic dynamometer 1. The flexible support hydraulic dynamometer 1 includes a water outlet 15, a rotor, and a housing as a stator. The housing is located above the water outlet 15. The rotor rotates inside the housing through its main shaft. The main shaft includes a free end and a load end. The load end is connected to the main shaft of the internal combustion engine 35 under test, and the free end is connected to the power input shaft through a dog clutch. The variable frequency motor 12 serves as a power unit, outputting speed and torque that match the speed, torque, and moment of inertia of the load. After the tested diesel internal combustion engine starts, the variable frequency motor 12 stops working. It also includes a rigid-flexible conversion component, which allows the connection between the housing and the water outlet 15 to switch between flexible support and rigid support through a detachable structure. During startup, the rigid support prevents the dynamometer spindle from wobbling. After the diesel engine starts and enters idle speed, the jaw clutch automatically disengages, allowing the dynamometer to return to the flexible support state.

[0034] In this application, the flexible support hydraulic dynamometer 1 refers to the dynamometer's rotor, stator, and housing being hinged to the water outlet tank 15 via four flexible support rods 104. The hinge connection is pre-tightened by an outer arm torsion spring (or leaf spring). The hinge connection's flexible support shaft is equipped with an elastic rubber block for damping and vibration reduction. Torque is transmitted through the power transmission arm 105. The tension and compression sensor 106 is used to test values ​​and serves as the basis for subsequent readings and calculations.

[0035] Preferably, this application selects a variable frequency motor 12. As can be seen from the current starting methods, there are two types of starting energy: air source and power source. The air source requires an additional air compressor, which also requires electrical energy. Moreover, the electric motor driven by electromagnetic force is the most important and efficient way to convert electrical energy into mechanical energy. Since the diesel engine starting process has requirements for climbing time and drag speed, the variable frequency motor 12 is selected as the power unit. The speed of the variable frequency motor 12 is selected as follows: the drag speed n1 and the maximum power Pmax of the internal combustion engine 35 under test during the starting process are obtained, the rated speed nm and rated power Pm of the variable frequency motor 12 are matched, the speed of the variable frequency motor 12 is reduced to increase the torque, a reducer 5 is added, the reduction ratio of the reducer 5 is i, and the motor speed must satisfy nm=n1*i and Pm≥Pmax.

[0036] Preferably, the rotational inertia of the variable frequency motor 12 is selected as follows: the rotational inertia of the drive and the load is set to 1:5, the rotational inertia of the tested internal combustion engine 35 is J3, the rotational inertia of the flexible support hydraulic dynamometer 1 is J2, and the rotational inertia of the variable frequency motor 12 is J1. The rotational inertia matching relationship of the variable frequency motor 12 is determined to be J1:(J2+J3)=1:5.

[0037] Preferably, during the test, the diesel engine J3 is the drive and the flexible support hydraulic dynamometer 1J2 is the load. According to the principle of matching rotational inertia, the ratio of J3 to J2 is designed to be 1:5. By setting the starting and climbing time, speed, and dragging time of the variable frequency motor 12, the intensity of the mechanical vibration generated by the diesel engine during the starting process can be adjusted.

[0038] Preferably, the main shaft of the variable frequency motor 12 is arranged horizontally and concentrically with the crankshaft of the internal combustion engine 35 under test, and the load end of the main shaft of the flexible support hydraulic dynamometer is set coaxially with the crankshaft of the internal combustion engine 35 under test, so as to realize the concentric transmission of speed and torque. On the one hand, it avoids the skipping and tooth collision phenomenon that occurs in the two parallel gear transmission, and on the other hand, it eliminates the possibility of overturning torque caused by the two transmission shafts being parallel but not concentric.

[0039] Preferably, such as Figure 2 and Figure 3 As shown, the rigid-flexible conversion component includes a fixed plate 101 and a connecting plate 102. The fixed plate 101 is located at the lower part of the outer shell at both axial ends of the flexible support hydraulic dynamometer 1, and the connecting plate 102 is fixed at the upper end of the outlet tank 15. The connecting plate 102 and the fixed plate 101 are detachably fixedly connected. By fixing and disassembling, the flexible support and the rigid support can be converted to each other. In this solution, there are four fixed plates 101, two at each end, which are symmetrically arranged relative to the vertical center line of the end face of the flexible support hydraulic dynamometer 1. The fixed plate 101 and the connecting plate 102 are connected by bolts. When fixed, they are locked. When converted to the flexible state, they are detached. Bolts can also be replaced by other detachable connecting parts such as screws.

[0040] Preferably, the overrunning jaw clutch is a one-way triangular overrunning jaw clutch, including a left overrunning jaw clutch 8 and a right overrunning jaw clutch 2 that are fitted together. The left overrunning jaw clutch 8 is rigidly connected to the coupling flange 7 at the free end. The coupling flange 7 is connected to the free end by a flat key and is interference-fitted, transmitting speed and torque in both directions. The outer ring of the right-side overrunning clutch 2 has an annular groove 21, and the inner ring has a spline structure inner hole. The inner hole is used in conjunction with the spline drive shaft 10. The right-side overrunning clutch 2 moves axially along the spline drive shaft 10 to transmit speed and torque, and disengages after the speed of the dynamometer exceeds the speed of the variable frequency motor. The other end of the spline drive shaft 10 is connected to the output shaft of the reducer 5 through a flexible coupling 4, which adjusts the displacement of the two shaft end faces in the X and Y directions and transmits speed and torque. The variable frequency motor 12 serves as the input end of the reducer 5, and the reducer 5 reduces the speed of the variable frequency motor 12 to increase the output torque. Furthermore, the outer ring of the spline drive shaft 10 is provided with a coaxial bearing 11. The bearing 11 is fixed on the bracket 3 by a bearing bracket to support the spline drive shaft 10 and limit the axial movement of the flexible coupling 4.

[0041] The conventional free end is a light shaft with a certain taper, which cannot directly realize the transmission of speed and torque. Because the taper of the free end spindle cannot be accurately measured, it is impossible to carry out the interference fit between the coupling flange tapered surface and the spindle tapered surface. Therefore, the free end is re-processed to make the tapered shaft into a cylindrical shape. Then, the coupling flange 7 is interference-fitted with the shaft of the free end and connected by a flat key to realize the bidirectional transmission of speed and torque between the spindle and the coupling flange.

[0042] Preferably, such as Figure 4 and Figure 5 As shown, a rolling element 93 is provided in the annular groove 21. The rolling element is located inside the manual shift fork. The manual shift fork has an H-shaped structure, including a frame 91 and a support column 92. Two rolling elements are symmetrically arranged inside the manual shift fork 92 and are mounted on the support column. The two are rotatably connected. The support column is slidably connected to the manual shift fork 92. The lower end of the manual shift fork is hinged to a fixed bracket 3. When the manual shift fork 9 is moved, the motor rotates, causing the rolling element to rotate in the annular groove 21 of the right-side jaw clutch. The support can move up and down within the frame, thus engaging the jaw clutch. When starting is required, the jaw clutch engages when the manual shift fork is moved, the motor rotates, the rolling element rotates in the annular groove 21 of the right-side jaw clutch, and the support can move up and down within the frame, thus assisting in the engagement of the jaw clutch. In practical applications, the support column and rolling element can be replaced by a bearing 11 with a handle, which is more cost-effective. The up and down sliding structure can be a linear guide slider structure or a similar slider structure.

[0043] Preferably, such as Figure 6As shown, the load end is connected to the main shaft of the internal combustion engine 35 under test through a universal joint 31, a coupling 32 and a connecting flange 33. The entire device is fixed on the base plate 20 to form an integral skid-mounted structure. The variable frequency motor 12 and the internal combustion engine under test are fixedly connected to the base plate 20 through a rigid support frame 6, which serves to support and fix them. At the same time, the manual lever fork is hinged to the bracket 3, and the bracket 3 is fixed on the base plate 20.

[0044] A starting method for an externally powered internal combustion engine equipped with a flexible-support hydraulic dynamometer includes the following steps. The first step is to fix the fixed plate 101 and the connecting plate 102 in the rigid-flexible conversion assembly to complete the conversion of the hydraulic dynamometer from flexible support to rigid support, so that the main shaft of the hydraulic dynamometer does not swing during startup. The second step involves engaging the overrunning clutch by manually shifting the fork 9 before starting, effectively transmitting power. Specifically, engaging the overrunning clutch by manually shifting the fork before starting allows for effective power transmission. This drives the diesel engine, which uses a variable frequency motor 12 to rotate the rigid support hydraulic dynamometer and the non-powered starting method, to rotate. When the driven speed reaches a certain speed, the diesel engine successfully starts under compression ignition, and the variable frequency motor 12 stops working. This is accompanied by the automatic disengagement of the starting device from the flexible support hydraulic dynamometer 1 due to the engagement profile of the overrunning clutch. The third step involves using the variable frequency motor 12 to drive the hydraulic dynamometer in a rigid support state and the diesel engine in a no-energy start mode to rotate. When the driving speed reaches a certain speed, the diesel engine successfully starts under compression ignition, and the variable frequency motor 12 stops working. Fourth step: After the diesel engine starts and enters idle speed, the starting device automatically disengages due to the engagement characteristics of the jaw clutch. The fixed connection between the fixing plate 101 and the connecting plate 102 is removed, and the hydraulic dynamometer is restored to a flexible support state.

[0045] This application addresses the problem of starting a test bench equipped with a flexible support hydraulic dynamometer 1 for a diesel engine without an external power source. The above-mentioned starting device is designed to achieve the hardening treatment of the flexible support dynamometer during the starting process and automatic separation after starting, i.e., restoring the flexible support state during the test. This satisfies the requirement for matching the rotational inertia of the drive and load when the flexible support dynamometer and the diesel engine act as each other's drive and load. It solves the problem of matching the rotational inertia of the drive and load during starting and testing. During starting, the variable frequency motor 12 (J1) acts as the drive, and the flexible support hydraulic dynamometer 1 (J2) and the diesel engine (J3) act as the load. This solution ensures that the diesel engine maintains the original test bench's rotational inertia, torsional resonance speed, and control response capability during testing, with high accuracy, clear functional zoning, and effective risk isolation.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions 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 within the scope of the claims and specification of the present invention.

[0047] The embodiments of this 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 substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A starting device for an internal combustion engine without external power source, equipped with a flexible support dynamometer, suitable for internal combustion engines without external power source starting and equipped with a flexible support hydraulic dynamometer stand, characterized in that: The flexible support hydraulic dynamometer comprises a water outlet groove, a rotor and a shell as a stator, the shell is arranged above the water outlet groove, the rotor rotates in the shell through a main shaft, the main shaft comprises a free end and a load end, the load end is connected with a main shaft of a diesel engine to be measured, and the free end is connected with a power input shaft through a jaw type overrunning clutch; The variable frequency motor is used as a power device, and the output rotation speed and torque are matched with the rotation speed, torque and moment of inertia of the load, the variable frequency motor stops working after the diesel engine to be measured starts; The rigid-flexible conversion assembly is arranged, the connection between the shell and the water outlet groove is converted between the flexible support and the rigid support through a detachable structure, the rigid support makes the main shaft of the dynamometer not swing during starting, the diesel engine enters an idle speed after starting, the jaw type overrunning clutch is automatically separated, and the dynamometer returns to the flexible support state.

2. The starting device for starting an internal combustion engine with a flexible support dynamometer without an external energy source according to claim 1, characterized in that: The rotation speed of the variable frequency motor is selected as follows: the drag rotation speed n1 and the maximum power Pmax of the starting process of the diesel engine to be measured are obtained, the rated rotation speed nm and the rated power Pm of the variable frequency motor are matched, the variable frequency motor is reduced in speed, the torque is increased, a speed reducer is additionally arranged, the speed reduction ratio of the speed reducer is i, and the rotation speed of the motor needs to satisfy nm = n1 * i and Pm >= Pmax.

3. The starting device for starting an internal combustion engine with a flexible support dynamometer without an external energy source according to claim 1, characterized in that: The moment of inertia of the variable frequency motor is selected as follows: the moments of inertia of the drive and the load are set as 1:5, the moment of inertia of the diesel engine to be measured is J3, the moment of inertia of the flexible support hydraulic dynamometer is J2, and the moment of inertia of the variable frequency motor is J1, and the matching relationship of the moment of inertia of the variable frequency motor is determined as J1:(J2+J3)=1:

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4. The starting device for starting an internal combustion engine with a flexible support dynamometer without an external energy source according to claim 3, characterized in that: During the test, the diesel engine J3 is used as the drive, the flexible support hydraulic dynamometer J2 is used as the load, according to the moment of inertia matching principle, J3:J2=1:5 is designed, the starting climbing time, the rotation speed and the drag time of the variable frequency motor are set, and the intensity of mechanical vibration generated by the diesel engine during the starting process is adjusted.

5. The starting device for starting an internal combustion engine with a flexible support dynamometer without an external energy source according to claim 1, characterized in that: The main shaft of the variable frequency motor is arranged in horizontal concentricity with the crankshaft of the diesel engine to be measured, and the load end of the main shaft of the flexible support hydraulic dynamometer is arranged in coaxiality with the crankshaft of the diesel engine to be measured.

6. The starting device for starting an internal combustion engine with a flexible support dynamometer without an external energy source according to claim 1, characterized in that: The rigid-flexible conversion assembly comprises a fixed plate and a connecting plate, the fixed plate is arranged at the lower part of both axial ends of the flexible support hydraulic dynamometer, the connecting plate is fixedly arranged at the upper end of the water outlet groove, and the connecting plate and the fixed plate are detachably fixedly connected, so that the flexible support and the rigid support are converted through fixing and detaching.

7. The starting device for starting an internal combustion engine with a flexible support dynamometer without an external energy source according to claim 1, characterized in that: The jaw type overrunning clutch is a one-way triangular jaw type overrunning clutch, comprising a left jaw type overrunning clutch and a right jaw type overrunning clutch arranged in cooperation, the left jaw type overrunning clutch is rigidly connected with a shaft flange of the free end, the shaft flange is connected with the free end through a key and is in interference fit, and the rotation speed and the torque are bidirectionally transmitted; The outer ring of the right jaw type overrunning clutch is provided with an annular groove, the inner ring is an inner hole with a spline structure, the inner hole is used in cooperation with the spline transmission shaft, the right jaw type overrunning clutch moves along the spline transmission shaft in the axial direction, the rotation speed and the torque are transmitted, and the right jaw type overrunning clutch is separated after the rotation speed of the dynamometer is greater than the rotation speed of the variable frequency motor; The other end of the spline transmission shaft is connected with the output shaft of the speed reducer through a plum blossom elastic coupling, and the variable frequency motor is used as the input end of the speed reducer.

8. The starting device for starting an internal combustion engine with a flexible support dynamometer without an external energy source according to claim 7, characterized in that: The annular groove is provided with rolling bodies, the rolling bodies are arranged in the manual yoke, the manual yoke is a h-shaped structure, the rolling bodies are two and symmetrically arranged on the inner side of the manual yoke, the rolling bodies are arranged on the support column and are rotationally connected, the support column is slidably connected to the manual yoke, the lower end of the manual yoke is hingedly connected to the fixed support, the manual yoke is actuated, the motor is rotated to drive the rolling bodies to rotate in the annular groove of the right side toothed clutch, the support can move up and down in the frame, and the toothed clutch is engaged.

9. The starting device for starting an internal combustion engine with a flexible support dynamometer without an external energy source according to claim 1, characterized in that: The load end is connected with the main shaft of the measured internal combustion engine through the cross universal shaft, the shaft coupling and the connecting flange plate, and the whole device is fixed on the foundation plate to form an integral skid-mounted structure.

10. A starting method of a starting device for starting an internal combustion engine with a dynamometer having a flexible support without an external energy source according to any one of claims 1 to 9, characterized in that: The method comprises the following steps, In the first step, the fixed plate and the connecting plate in the rigid-flexible conversion assembly are fixedly connected, the conversion from the flexible support to the rigid support of the water brake is completed, and the water brake main shaft does not swing during starting; In the second step, the toothed overrunning clutch is engaged by actuating the manual yoke before starting, and the power is effectively transmitted; In the third step, the variable frequency motor is used to drive the water brake in the rigid support state and the diesel engine in the non-energy starting mode to rotate, and when the driving speed reaches a certain speed, the diesel engine is successfully started, and the variable frequency motor stops working; In the fourth step, after the diesel engine is started, the idle speed is entered, the starting device is automatically separated due to the engagement line characteristics of the toothed overrunning clutch, the fixed connection of the fixed plate and the connecting plate is removed, and the water brake is restored to the flexible support state.

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