A low-inertia electrically assisted supercharger and control method

Abstract

The application provides a low-inertia electric auxiliary supercharger and a control method, which comprises a rotating shaft, a turbine and a supercharger wheel mounted at both ends of the rotating shaft respectively, and an external spline fixed on the rotating shaft; a shell, the rotating shaft being rotatably connected with the shell; a ring-shaped magnetic steel, the ring-shaped magnetic steel being movably connected with the rotating shaft along the axial direction of the rotating shaft, and an internal spline matched with the external spline being formed on the inner side of one end of the ring-shaped magnetic steel; a motor coil, the motor coil being fixedly installed on the inner side of the shell, and the motor coil being located on the outer side of the ring-shaped magnetic steel; and a driving assembly, the driving assembly being used for driving the ring-shaped magnetic steel to move. The application has the beneficial effects that the ring-shaped magnetic steel is connected with the rotating shaft through the spline, in the high rotating speed stage, the magnetic steel is separated from the rotating shaft and rotates freely, the inertia of the motor rotor is not superimposed on the rotating shaft of the supercharger, the rotating inertia of the rotating shaft is effectively reduced, the turbine hysteresis is reduced, the centrifugal stress and the number of thermal shocks borne by the magnetic steel are reduced, and the demagnetization of the magnetic steel is effectively prevented.

Description

Technical Field

[0001] This invention belongs to the field of engine turbocharger technology, and in particular relates to a low-inertia electric auxiliary turbocharger and its control method. Background Technology

[0002] Since their widespread application, exhaust gas turbochargers have become a core component for improving the power density of internal combustion engines and reducing fuel consumption. However, the insufficient exhaust gas energy at low engine speeds, leading to "turbo lag," remains a pain point in the industry. To alleviate this lag, electric-assisted turbochargers have emerged. The basic idea is to arrange an electric motor coaxially on the turbine shaft. At low speeds, the motor actively performs work, while at high speeds, the motor switches to generator mode or idles.

[0003] In existing technologies, the motor rotor (permanent magnet or induction squirrel cage) is directly heat-mounted to the turbine shaft or fixed with a sleeve. While this structure is simple, it has the following drawbacks: First, the rotor inertia is superimposed on the turbine shaft. When the engine is under high load, the shaft rotates at high speed, but the motor is not working. The permanent magnet still rotates at high speed with the shaft. On the one hand, the rotor inertia increases the load on the shaft, and on the other hand, centrifugal force and thermal shock cause irreversible demagnetization of the magnets, reducing their service life. Second, the connection between the rotor and the shaft requires a dynamic balance level of G1.0 or higher, which significantly increases the manufacturing difficulty and cost. Moreover, if the motor fails, the rotor mass becomes an additional burden, reducing the maximum speed by 5%–8%, directly affecting the engine's rated power. Summary of the Invention

[0004] In view of this, the present invention aims to provide a low-inertia electrically assisted turbocharger and control method, in order to solve at least one of the above-mentioned technical problems.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A low-inertia electrically assisted turbocharger, comprising: A rotating shaft, with a turbine and a booster wheel respectively installed at both ends of the rotating shaft, and an external spline fixed on the rotating shaft; The outer casing, and the rotating shaft is rotatably connected to the outer casing; A ring magnet, wherein the ring magnet is movably connected to the rotating shaft along the axial direction, and an internal spline matching the external spline is opened on the inner side of one end of the ring magnet; The motor coil is fixedly installed inside the housing and located outside the annular magnet. A drive assembly for driving the movement of a ring magnet.

[0006] Furthermore, one end of the outer casing has a mounting hole, and the other end of the outer casing is provided with a mounting plate, which has a mounting hole. One end of the rotating shaft is rotatably connected to the inner side of the mounting hole of the housing via a first bearing; The other end of the shaft is rotatably connected to the inner side of the mounting hole two on the mounting plate via another first bearing; The mounting plate is detachably connected to the outer casing by bolts.

[0007] Furthermore, the diameter of the annular magnet is larger than the diameter of the mounting hole one; The drive assembly includes an electromagnet and a return spring. The electromagnet is installed on the inner side of the end of the housing away from the mounting plate, and the position of the electromagnet corresponds to that of the annular magnet. When the electromagnet is energized, it generates magnetic force that drives the annular magnet to move toward the outer spline of the rotating shaft. The outer spline is inserted into the inner spline, and the rotating shaft and the annular magnet rotate synchronously. When the electromagnet is not energized, the return spring provides elastic force to drive the annular magnet to move away from the outer spline of the rotating shaft, and the outer spline disengages from the inner spline.

[0008] Furthermore, the reset spring is a helical spring, located on the outside of the rotating shaft. One end of the helical spring is located on the inside of the mounting hole and corresponds to the outer ring of the first bearing, while the other end of the helical spring corresponds to the annular magnet.

[0009] Furthermore, the reset spring is a butterfly spring, which is located between the annular magnet and the inner end face of the outer shell away from the mounting plate.

[0010] Furthermore, the inner diameter of the annular magnet is larger than the outer diameter of the rotating shaft, and the outer side of the annular magnet is rotatably connected to the outer shell through a second bearing.

[0011] Furthermore, a sleeve is fixedly provided on the outer side of the annular magnet, and the outer side of the sleeve is rotatably connected to the outer shell through a second bearing.

[0012] Furthermore, a position sensor corresponding to the external spline is fixedly mounted on the outer side of the housing.

[0013] A second aspect of the present invention provides a control method for using the low-inertia electric auxiliary turbocharger described in the first aspect, comprising the following steps: S1. During the low speed stage of the engine, the electromagnet is energized and the electromagnet generates magnetic force to drive the ring magnet to move towards the outer spline of the shaft. The outer spline is inserted into the inner spline, and the shaft and the ring magnet rotate synchronously. S2. The motor coil is energized, which drives the annular magnet and the shaft to rotate. S3. When the rotational speed exceeds the speed threshold, the electromagnet is turned off. The reset spring provides elastic force to drive the annular magnet to move away from the external spline of the rotational shaft. The external spline disengages from the internal spline, and the annular magnet does not rotate synchronously with the rotational shaft.

[0014] Furthermore, in S1, after the electromagnet is energized, the spline engagement result is determined by whether the position sensor detects the annular magnet. If the position sensor detects the ring magnet, it determines that the external spline has been inserted into the inside of the internal spline, and proceeds to S2; If the position sensor does not detect the ring magnet, it is determined that the external spline is not inserted into the inner spline, and alarm data is sent.

[0015] Compared with the prior art, the low-inertia electrically assisted turbocharger and control method described in this invention have the following advantages: (1) The low inertia electric auxiliary turbocharger of the present invention uses a ring magnet to engage and disengage with the shaft through a spline. In the high speed stage, the magnet is separated from the shaft and rotates freely, without superimposing the motor rotor inertia onto the turbocharger shaft. This effectively reduces the shaft rotational inertia, reduces turbine hysteresis, reduces the centrifugal stress and thermal shock frequency borne by the magnet, and effectively prevents the magnet from demagnetizing.

[0016] (2) The low inertia electric auxiliary turbocharger control method of the present invention determines the spline engagement result by whether the position sensor detects the annular magnet, prevents the motor from driving when the spline is not engaged, avoids motor overload, spline wear or shaft impact caused by incomplete engagement, and improves the safety and reliability of the whole machine. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic cross-sectional view of the low-inertia electrically assisted turbocharger according to an embodiment of the present invention; Figure 2 As described in the embodiments of the present invention Figure 1 Schematic diagram of the structure at point A in the middle; Figure 3 This is a schematic diagram of the low-inertia electric-assisted turbocharger control method according to an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 1. Pressure booster wheel; 2. Housing; 3. First bearing; 4. Motor coil; 5. Second bearing; 6. Ring magnet; 7. Sleeve; 8. Electromagnet; 9. Turbine; 10. Shaft; 11. Position sensor; 12. Return spring; 13. Internal spline; 14. External spline; 201. Mounting plate. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] like Figures 1 to 2 As shown, a low-inertia electrically assisted turbocharger includes: A rotating shaft 10 is provided with a turbine 9 and a booster wheel 1 installed at both ends of the rotating shaft 10, and an external spline 14 is fixed on the rotating shaft 10. The outer casing 2 and the rotating shaft 10 are rotatably connected to the outer casing 2; The annular magnet 6 is movably connected to the rotating shaft 10 along the axial direction of the rotating shaft 10. An inner spline 13 matching the outer spline 14 is opened on the inner side of one end of the annular magnet 6. Motor coil 4 is fixedly installed inside the housing 2 and located outside the annular magnet 6. The drive component is used to drive the annular magnet 6 to move.

[0024] Turbine 9 is installed inside the turbine 9 housing (not shown in the figure). The intake pipe of the turbine 9 housing is connected to the exhaust pipe of the engine, and the exhaust pipe of the turbine 9 housing is connected to the exhaust gas treatment device. The supercharger 1 is installed inside the supercharger housing (not shown in the figure). The exhaust pipe of the supercharger housing is connected to the intake pipe of the engine. The intake pipe of the supercharger housing is connected to the atmosphere through the filter assembly. The internal spline 13 is coated with a Ni-Cu-Ni+Epoxy composite coating, which is resistant to salt spray for ≥1000h and prevents high-temperature oxidation and corrosion. The internal spline 13 has its keyway machined before the magnet is magnetized and then undergoes glow discharge ion nitriding treatment, with a surface hardness of ≥900HV and a nitriding layer depth of 0.02–0.04mm, which improves its wear resistance.

[0025] After the external spline 14 and the shaft 10 are machined as a single unit, they are subjected to glow discharge ion nitriding treatment, with a surface hardness ≥900HV and a nitriding layer depth of 0.02–0.04mm, which improves wear resistance.

[0026] The meshing tooth profile of the external spline 14 and the internal spline 13 is an involute with a pressure angle of 30° and a module of 0.5–1.0. The tooth tip is trimmed to reduce axial engagement impact noise ≤5dB(A).

[0027] The motor consists of a motor coil 4 and a toroidal magnet 6. The motor is a 6-pole, 9-slot permanent magnet synchronous motor with a peak power of 3–7kW and a maximum speed of 120krpm. The control strategy adopts Id=0+ field weakening speed regulation, and the efficiency is ≥92%.

[0028] One end of the outer casing 2 has a mounting hole 1, and the other end of the outer casing 2 is provided with a mounting plate 201. The mounting plate 201 has a mounting hole 2. One end of the rotating shaft 10 is rotatably connected to the inner side of the mounting hole 1 of the outer casing 2 through a first bearing 3. The other end of the rotating shaft 10 is rotatably connected to the inner side of the mounting hole 2 of the mounting plate 201 through another first bearing 3. The setting of the first bearing 3 reduces the friction between the rotating shaft 10 and the outer casing 2.

[0029] Mounting plate 201 is detachably connected to housing 2 by bolts. The detachable nature of mounting plate 201 facilitates the installation of ring magnet 6 and motor coil 4.

[0030] The diameter of the annular magnet 6 is larger than the diameter of the mounting hole 1; the drive assembly includes an electromagnet 8 and a return spring 12. The electromagnet 8 is installed on the inner side of the end of the housing 2 away from the mounting plate 201, and the positions of the electromagnet 8 and the annular magnet 6 correspond to each other; when the electromagnet 8 is energized, the electromagnet 8 generates magnetic force to drive the annular magnet 6 to move towards the outer spline 14 of the rotating shaft 10, and the outer spline 14 is inserted into the inner spline 13, and the rotating shaft 10 and the annular magnet 6 rotate synchronously; when the electromagnet 8 is not energized, the return spring 12 provides elastic force to drive the annular magnet 6 to move towards the outer spline 14 away from the rotating shaft 10, and the outer spline 14 disengages from the inner spline 13.

[0031] Electromagnet 8 uses a 12V or 48V vehicle power supply, with a peak current ≤15A, a pull-in time of 80–120ms, a residual magnetic force <0.5N·m after power failure, and a pull-in force of 120N.

[0032] In some embodiments, the return spring 12 is a helical spring (not shown in the figure). The helical spring is located on the outside of the rotating shaft 10. One end of the helical spring is located on the inside of the mounting hole 1 and corresponds to the outer ring of the first bearing 3. The other end of the helical spring corresponds to the annular magnet 6. The material of the helical spring is high temperature resistant alloy GH4169, and the return force is 20–40 N.

[0033] In other embodiments, the return spring 12 is a butterfly spring, located between the annular magnet 6 and the inner end face of the outer casing 2 at the end furthest from the mounting plate 201. The butterfly spring is made of high-temperature resistant alloy GH4169 with a fatigue life ≥10. 7 Each time, the reset force is 20–40 N.

[0034] The inner diameter of the annular magnet 6 is larger than the outer diameter of the rotating shaft 10. The outer side of the annular magnet 6 is rotatably connected to the outer casing 2 through the second bearing 5. The second bearing 5 provides support for the annular magnet 6. When the outer spline 14 disengages from the inner spline 13, the inner side of the annular magnet 6 is not in contact with the rotating shaft 10.

[0035] A sleeve 7 is fixedly mounted on the outer side of the annular magnet 6, and the outer side of the sleeve 7 is rotatably connected to the outer casing 2 via a second bearing 5. The sleeve 7 serves to protect the annular magnet 6. A position sensor 11 corresponding to the external spline 14 is fixed on the outer side of the housing 2. The position sensor 11 adopts, but is not limited to, the existing eddy current position sensor 11, with a measurement accuracy of ±0.05mm, a response time of <1ms, and a temperature range of -40℃ to 200℃. It is used to detect whether the annular magnet 6 has reached the designated position.

[0036] Work process: like Figure 3 As shown, a control method for a low-inertia electrically assisted turbocharger includes the following steps: S1. During the low speed stage of the engine, the electromagnet 8 is energized and the electromagnet 8 generates magnetic force to drive the annular magnet 6 to move towards the outer spline 14 of the rotating shaft 10. The outer spline 14 is inserted into the inner spline 13 and the rotating shaft 10 and the annular magnet 6 rotate synchronously. S2, the motor coil 4 is energized, which drives the annular magnet 6 and the rotating shaft 10 to rotate; S3. When the rotation of the shaft 10 exceeds the speed threshold, the electromagnet 8 is turned off, and the reset spring 12 provides elastic force to drive the annular magnet 6 to move away from the outer spline 14 of the shaft 10. The outer spline 14 disengages from the inner spline 13, and the annular magnet 6 does not rotate synchronously with the shaft 10.

[0037] The speed threshold is 70% of the turbocharger's rated speed.

[0038] In S1, after the electromagnet 8 is energized, the spline engagement result is determined by whether the position sensor 11 detects the annular magnet 6. If the position sensor 11 detects the annular magnet 6, it determines that the outer spline 14 has been inserted into the inner spline 13 and proceeds to S2. If the position sensor 11 does not detect the annular magnet 6, it determines that the external spline 14 is not inserted into the inner spline 13 and sends alarm data.

[0039] The position sensor 11 determines the spline engagement result by detecting the annular magnet 6, preventing motor drive when the spline is not engaged, avoiding motor overload, spline wear or shaft 10 impact caused by incomplete engagement, and improving the overall safety and reliability of the machine.

[0040] The annular magnet 6 is engaged with the rotating shaft 10 via a spline. During high-speed operation, the magnet is disengaged from the rotating shaft 10 and rotates freely, without adding the motor rotor inertia to the turbocharger rotating shaft 10. This effectively reduces the rotational inertia of the rotating shaft 10, reduces the hysteresis of the turbine 9, and reduces the centrifugal stress and thermal shock frequency experienced by the magnet, thus effectively preventing the magnet from demagnetizing.

[0041] In addition, the annular magnet 6 rotates synchronously with the rotating shaft 10 only during low-speed operation, which reduces the requirements for dynamic balance, thereby reducing the requirements for machining accuracy and manufacturing costs.

[0042] 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 present invention, and they should all be covered within the scope of the claims and specification of the present invention.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-inertia electrically assisted turbocharger, characterized in that, include: A rotating shaft (10) is provided with a turbine (9) and a booster wheel (1) installed at both ends of the rotating shaft (10), and an external spline (14) is fixed on the rotating shaft (10). The outer casing (2) is rotatably connected to the rotating shaft (10); An annular magnet (6) is movably connected to the rotating shaft (10) along the axial direction. An inner spline (13) matching the outer spline (14) is opened on the inner side of one end of the annular magnet (6). The motor coil (4) is fixedly installed on the inner side of the outer casing (2) and the motor coil (4) is located on the outer side of the annular magnet (6); A drive assembly for driving the annular magnet (6) to move.

2. The low-inertia electrically assisted turbocharger according to claim 1, characterized in that: One end of the outer casing (2) has a mounting hole 1, and the other end of the outer casing (2) is provided with a mounting plate (201), on which a mounting hole 2 is provided. One end of the rotating shaft (10) is rotatably connected to the inner side of the mounting hole of the outer casing (2) through a first bearing (3); The other end of the rotating shaft (10) is rotatably connected to the inner side of the mounting hole two of the mounting plate (201) through another first bearing (3); The mounting plate (201) is detachably connected to the outer casing (2) by bolts.

3. The low-inertia electrically assisted turbocharger according to claim 1, characterized in that: The diameter of the annular magnet (6) is larger than the diameter of the mounting hole one; The drive assembly includes an electromagnet (8) and a return spring (12). The electromagnet (8) is installed on the inner side of the end of the housing (2) away from the mounting plate (201). The position of the electromagnet (8) corresponds to that of the annular magnet (6). When the electromagnet (8) is energized, the electromagnet (8) generates magnetic force to drive the ring magnet (6) to move towards the outer spline (14) of the rotating shaft (10). The outer spline (14) is inserted into the inner spline (13), and the rotating shaft (10) and the ring magnet (6) rotate synchronously. When the electromagnet (8) is not energized, the return spring (12) provides elastic force to drive the annular magnet (6) to move away from the outer spline (14) of the rotating shaft (10), and the outer spline (14) disengages from the inner spline (13).

4. A low-inertia electrically assisted turbocharger according to claim 3, characterized in that: The reset spring (12) is a helical spring. The helical spring is located on the outside of the rotating shaft (10). One end of the helical spring is located on the inside of the mounting hole and corresponds to the outer ring of the first bearing (3). The other end of the helical spring corresponds to the annular magnet (6).

5. A low-inertia electrically assisted turbocharger according to claim 3, characterized in that: The reset spring (12) is a butterfly spring, which is located between the annular magnet (6) and the inner end face of the outer shell (2) away from the mounting plate (201).

6. A low-inertia electrically assisted turbocharger according to claim 1, characterized in that: The inner diameter of the annular magnet (6) is larger than the outer diameter of the rotating shaft (10), and the outer side of the annular magnet (6) is rotatably connected to the outer shell (2) through the second bearing (5).

7. A low-inertia electrically assisted turbocharger according to claim 6, characterized in that: A sleeve (7) is fixed on the outside of the annular magnet (6), and the outside of the sleeve (7) is rotatably connected to the outer shell (2) through a second bearing (5).

8. A low-inertia electrically assisted turbocharger according to claim 1, characterized in that: A position sensor (11) corresponding to the external spline (14) is fixed on the outside of the housing (2).

9. A control method for using the low-inertia electrically assisted turbocharger according to any one of claims 1-8, characterized in that, Includes the following steps: S1. During the low speed stage of the engine, the electromagnet (8) is energized and the electromagnet (8) generates magnetic force to drive the ring magnet (6) to move towards the outer spline (14) of the rotating shaft (10). The outer spline (14) is inserted into the inner spline (13), and the rotating shaft (10) and the ring magnet (6) rotate synchronously. S2. The motor coil (4) is energized, which drives the annular magnet (6) and the rotating shaft (10) to rotate. S3. When the rotating shaft (10) rotates above the speed threshold, the electromagnet (8) is turned off, and the reset spring (12) provides elastic force to drive the ring magnet (6) to move away from the outer spline (14) of the rotating shaft (10). The outer spline (14) disengages from the inner spline (13), and the ring magnet (6) does not rotate synchronously with the rotating shaft (10).

10. A low-inertia electrically assisted turbocharger according to claim 9, characterized in that: In S1, after the control electromagnet (8) is energized, the spline mating result is determined by whether the position sensor (11) detects the annular magnet (6); If the position sensor (11) detects the annular magnet (6), it determines that the external spline (14) has been inserted into the inside of the internal spline (13) and enters S2; If the position sensor (11) does not detect the annular magnet (6), it is determined that the external spline (14) is not inserted into the inner spline (13) and alarm data is sent.

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