An electromagnetic fan clutch anti-wear and noise reduction device

Abstract

The utility model relates to a fan clutch, specifically an electromagnetic fan clutch anti-wear and noise reduction device, including an integrated vehicle-mounted control unit or computing device, which can calculate the driving speed according to the real-time engine speed. The device includes current detection, PWM drive and speed detection modules, which are particularly suitable for two-speed or three-speed clutches, and the power supply of the electromagnetic coil is controlled by MOSFET to achieve precise control. The speed sensor is installed on the shaft seat of the fan clutch for real-time monitoring. Compared with the existing technology, the device effectively reduces wear, reduces noise, and improves driving comfort.

Description

Technical Field

[0001] The utility model relates to a fan clutch, and more specifically to an electromagnetic fan clutch anti-wear and noise reduction device. Background Art

[0002] The statements in this section merely provide background technology related to the present invention and do not necessarily constitute prior art.

[0003] In the field of mechanical engineering such as automobiles, tractors, and construction machinery, the cooling system of the internal combustion engine is a vital component. At present, the engine cooling system generally adopts air cooling to cool the water temperature of the engine heat circulation system through the cooling fan. In order to achieve variable speed control of the fan, an electromagnetic fan clutch is usually equipped between the cooling fan and the engine. This clutch uses the induction principle of the electromagnetic coil to adjust the speed of the cooling fan, aiming to save fuel and reduce energy consumption.

[0004] Although the existing electromagnetic fan clutch is simple and reliable in structure, and has a quick response and short engagement time, its performance still needs to be improved under certain working conditions. Specifically, when the existing fan clutch is working at full speed, it does not control the engagement time separately, but directly supplies full voltage to the fan clutch through the engine control unit (ECU) or the temperature control switch. Although this control method is suitable for systems with small speed slip or small load changes, it shows its limitations under conditions of high speed difference or large load mutation: under the condition of high speed difference or large load mutation, when the existing fan clutch is engaged at full speed, the friction between the driving surface and the driven surface of the fan clutch is not enough to match the wind resistance of the fan, and slippage may occur, resulting in abnormal wear of the friction engagement surface, accompanied by obvious fan noise problems. These problems not only affect the service life of the clutch, but also have a negative impact on the comfort of the driver and passengers.

[0005] The technical directions that technical personnel in this field are currently focusing on are mainly concentrated on improving cooling efficiency, reducing energy consumption and optimizing the response speed of the fan control system. These research directions may be of great significance for improving the overall performance and fuel economy of the engine. However, the technical problems of engagement noise and abnormal wear of the friction engagement surface have not been noticed, or although the technical problems have been discovered, they are considered to be inherent characteristics of the electromagnetic fan clutch and are ignored. Therefore, there is no technical solution to solve the technical problem in the prior art. Utility Model Content

[0006] This utility model is aimed at this neglected technical problem and proposes an innovative solution, which aims to reduce the fan clutch engagement noise, improve driving comfort, reduce abnormal wear of the friction engagement surface, and extend the service life of the fan clutch. To this end, the technical solution adopted by the utility model is:

[0007] An electromagnetic fan clutch anti-wear and noise reduction device includes a vehicle-mounted control unit or an additional computing device. Different from the prior art, the vehicle-mounted control unit or the additional computing device can calculate the driving speed of the fan clutch according to the real-time speed of the engine; it also includes a current detection module, a PWM drive module and a speed detection module connected to the vehicle-mounted control unit or the additional computing device; when the electromagnetic fan clutch is a two-speed clutch, the ammeter of the current detection module and the MOSFET of the PWM drive module are connected in series to the power supply line of the electromagnetic coil; when the electromagnetic fan clutch is a three-speed clutch, the ammeter of the current detection module and the MOSFET of the PWM drive module are connected in series to the power supply line of the electromagnetic coil of the two coils that controls the direct drive of the clutch to work at full speed; the speed sensor of the speed detection module is installed on the shaft seat of the fan clutch.

[0008] Furthermore, the computing device is a single chip microcomputer.

[0009] Furthermore, the real-time speed of the engine is obtained by reading data from the ECU or an engine sensor.

[0010] Furthermore, the drain of the MOSFET is connected to the positive electrode of the power supply, the source is connected to the negative electrode of the power supply, and the gate is connected to the on-board control unit or an additional computing device.

[0011] Furthermore, the rotation speed sensor is preferably a code disc and a Hall sensor.

[0012] Compared with the prior art, the beneficial technical effects of the utility model are mainly reflected in the following aspects:

[0013] Reduce noise: By smoothing the fan clutch's engagement process, the vibration and noise caused by engagement impact are reduced, improving driving comfort.

[0014] Reduce abnormal wear: The structure of the utility model combined with the control strategy can extend the engagement time of the fan clutch, effectively avoiding abnormal wear caused by high speed difference or large load mutation, and improving the durability and reliability of the fan clutch.

[0015] Prolong service life: The utility model structure combined with the control strategy can reduce wear and tear, improve the use of the working running-in surface of the clutch, and thus prolong the service life of the fan clutch.

[0016] Reduce costs: Through the structure of the utility model and the combination of control strategies, the initial design torque requirement of the fan clutch can be reduced, and the consumption of raw materials such as iron and copper can be reduced, thereby reducing production costs.

[0017] Improve system integration: The method and device of the utility model can be easily integrated into an existing vehicle-mounted control unit or additional computing equipment without large-scale changes to the existing system, and has good compatibility and scalability.

[0018] Simplified Maintenance: Due to the extended service life of the fan clutch, maintenance intervals can be extended, reducing maintenance frequency and costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of Example 1.

[0020] Figure 2 This is a schematic diagram of the structure of Example 2.

[0021] Figure 3 This is a schematic diagram of current changes detected by the ammeter of the utility model. DETAILED DESCRIPTION

[0022] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present disclosure belongs.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0024] Embodiment 1, a two-speed electromagnetic fan clutch anti-wear and noise reduction device, including an additional computing device 1, the computing device 1 can calculate the driving speed of the fan clutch according to the real-time speed of the engine; also includes a current detection module 2, a PWM drive module 3 and a speed detection module 4 connected to the computing device 1; the ammeter 21 of the current detection module 2 and the MOSFET31 of the PWM drive module 4 are connected in series to the power supply line 100 of the electromagnetic coil, and the speed sensor 41 of the speed detection module 4 is installed on the shaft seat of the fan clutch. The computing device 1 is a single-chip microcomputer; the real-time speed of the engine is obtained by reading the data in the ECU or the engine sensor; the drain of the MOSFET31 is connected to the positive pole of the power supply, the source is connected to the negative pole of the power supply, and the gate is connected to the vehicle-mounted control unit or the additional computing device 1; the speed sensor 41 is a code disk and a Hall sensor.

[0025] PWM drive module, namely pulse width modulation controller, is an electronic device used to generate and control pulse width modulation signals. PWM signal is a periodic square wave signal, which is characterized by that the duration of high level can be changed in one cycle, while the frequency remains constant. PWM controllers are widely used in various electronic systems. PWM controllers can adjust the duty cycle of the output signal, that is, the percentage of high level in one cycle. The change of duty cycle can control the average power of the load connected to the PWM output. In the motor drive system, PWM controller is used to adjust the speed and torque of the motor. In power management, PWM controller is used to adjust the output voltage and current to improve power efficiency.

[0026] MOSFET is short for Metal Oxide Semiconductor Field Effect Transistor; it is a commonly used semiconductor device with three main electrodes: Source: The source is usually the output terminal of the current in the MOSFET. In N-channel MOSFET, the source is connected to the N-type semiconductor region, while in P-channel MOSFET, the source is connected to the P-type semiconductor region. Drain: The drain is the input terminal of the current in the MOSFET. Similar to the source, in N-channel MOSFET, the drain is also connected to the N-type semiconductor region, while in P-channel MOSFET, the drain is connected to the P-type semiconductor region. When the MOSFET is turned on, the current flows from the drain to the source. Gate: The gate is the electrode that controls the switch of the MOSFET. It is isolated from the semiconductor substrate below by an insulating oxide layer. The voltage applied to the gate can control the formation and closing of the conductive channel between the source and the drain. In N-channel MOSFET, it is turned on when the gate voltage is higher than the source voltage; in P-channel MOSFET, it is turned on when the gate voltage is lower than the source voltage. In PWM control, MOSFET is usually used to control the power line connected to the load (such as motors, fans, LEDs, etc.). The control signal output by the PWM controller (usually a square wave signal with adjustable duty cycle) is used to adjust the switching state of the MOSFET, thereby adjusting the average voltage and power on the load. In this way, PWM control can accurately control the speed, brightness or other performance parameters of the load.

[0027] Embodiment 2, a three-speed electromagnetic fan clutch anti-wear and noise reduction device, is the same as Embodiment 1 in other aspects, except that the ammeter 21 of the current detection module 2 and the MOSFET 31 of the PWM drive module 3 are connected in series on the power supply circuit 100 of the electromagnetic coil that controls the direct drive of the clutch at full speed in the two coils.

[0028] The above embodiment records the hardware part of the anti-wear and noise reduction device of the two-speed or three-speed electromagnetic fan clutch. In practical applications, corresponding control strategies are also required to achieve the effect of anti-wear and noise reduction. The specific control method can adopt any method in the prior art that can extend the engagement time of the driving surface and the driven surface. The following are several controllable methods:

[0029] 1. Based on open-loop control strategy:

[0030] S1. Obtain the real-time speed of the engine, which is obtained by directly reading the ECU or the engine sensor;

[0031] S2. According to the preset speed ratio of the engine speed and the fan clutch, the driving speed of the fan clutch driving surface is calculated, denoted as N ';

[0032] S3 obtains the real-time speed of the fan blade of the fan clutch, denoted as N, the real-time speed of the fan blade of the fan clutch is collected by the code disc and Hall sensor installed on the fan clutch;

[0033] S4. Get the inflection point current of the fan clutch, see the attached Figure 3 :

[0034] S41. Use a current sensor to measure the current of the electromagnetic coil of the fan clutch. When the fan clutch is in the process of being attracted, the current will experience a process of first increasing, then decreasing, and then increasing again;

[0035] S42. Identify and determine the highest point in the current change, which is the inflection point current, which is the peak value of the current response when the fan clutch begins to engage;

[0036] S5. Calculate the inflection point voltage according to the resistance value of the fan clutch electromagnetic coil;

[0037] S6. Based on the voltage value of the inflection point voltage, gradually increase the power supply voltage of the fan clutch until it reaches full voltage power supply. The duration of the incremental process is recorded as B, and the value range of B is preferably 0.1 seconds to 20 seconds; when the fan clutch is in the process of being engaged, but no inflection point current is detected, the clutch power supply voltage directly performs full voltage power supply to avoid abnormal working state of the clutch due to failure of the inflection point current acquisition module. The voltage value of the full voltage power supply is 12-16V or 24-30V, depending on the electrical system configuration of the vehicle.

[0038] The detailed steps for gradually increasing the supply voltage to the fan clutch include:

[0039] SK1. Preset at least two different target speeds, namely, a first target speed N1 and a second target speed N2, satisfying N1>N2, wherein N1 and N2 are in the same order of magnitude as N;

[0040] SK2. Preset two different incremental voltage percentages, namely a first incremental voltage percentage A1% and a second incremental voltage percentage A2%, satisfying A1%>A2%, A1: 3%-25%, A2: 0.5%-18%; in this embodiment, A1% is full voltage × 10% / s, A2% is full voltage × 6% / s, if the output voltage of the vehicle battery in this embodiment is 24V, then A1%=2.4V / s, A2%=1.44 V / s.

[0041] SK3. Determine the relationship between the drive speed N and the target speed, and handle it according to the following three situations:

[0042] If N'>N1, the inflection point voltage plus the increment voltage percentage of A1% is sent as the duty cycle control signal to the PWM controller, and the PWM controller adjusts the supply voltage of the fan clutch electromagnetic coil according to the duty cycle control signal; the fan clutch electromagnetic coil is powered;

[0043] In this case, the system uses a higher increment voltage percentage A1% based on the knee voltage, which can quickly respond to the high cooling demand of the engine. The higher increment percentage means that the supply voltage will increase to full voltage faster, thereby quickly increasing the fan speed to meet the cooling demand under high load. This fast response helps prevent the engine from overheating, while avoiding sudden impact on the fan clutch by starting the increment from the knee voltage.

[0044] If N1≥N'>N2, the inflection point voltage plus the increasing voltage percentage of A2% is sent as the duty cycle control signal to the PWM controller, and the PWM controller adjusts the supply voltage of the fan clutch electromagnetic coil according to the duty cycle control signal; the fan clutch electromagnetic coil is powered;

[0045] In this case, using a lower increment voltage percentage A2% allows the system to adjust the fan speed more smoothly, reducing wear on the fan clutch. The lower increment percentage provides a more gradual voltage increase, which helps reduce the wear of the fan clutch caused by sudden voltage changes under medium loads. This progressive control strategy helps extend the service life of the fan clutch and keep the system running efficiently.

[0046] If N'≤N2, the freezing fan clutch power supply voltage increases and switches to full voltage power supply.

[0047] In this case, the fan clutch engagement process has been completed or nearly completed, and switching to full voltage power supply at this time will not cause abnormal wear due to excessive speed difference.

[0048] The handling of these three situations provides a detailed control strategy to adapt to different engine operating conditions, ensuring smooth operation of the fan clutch and reducing abnormal wear. This control method helps improve energy efficiency under low load conditions and ensures stable operation of the fan clutch when frequent adjustments are not required.

[0049] Overall, the handling of these three situations provides an adaptable, responsive and thoughtful fan clutch control strategy. By dynamically adjusting the supply voltage according to the real-time engine speed, this strategy can reduce wear and noise while ensuring cooling efficiency, and improve the reliability and service life of the entire cooling system. In addition, this control strategy is also very flexible and scalable, and can adapt to different vehicle models and different operating conditions.

[0050] 2. Based on closed-loop control strategy:

[0051] Steps S1-S5 are the same as those in Example 1, except that in step S6, the supply voltage of the fan clutch is gradually increased by using a PID algorithm, and the supply voltage is increased by speed control. The specific detailed steps include:

[0052] SBZ1. Calculate the difference between the drive speed N' and the real-time speed N;

[0053] SBZ2. Set M calibrated speeds Nb between the real-time speed N and the drive speed N';

[0054] SBZ3. Calculate the difference between the rated speed Nb and the real-time speed N;

[0055] SBZ4. The difference between Nb and N is used as the input of the PID algorithm;

[0056] SBZ5.PID algorithm calculates the output value based on the input difference and internal parameters;

[0057] SBZ6. Send the output value as a duty cycle control signal to the PWM controller;

[0058] The SBZ7.PWM controller adjusts the supply voltage of the fan clutch electromagnetic coil according to the duty cycle control signal;

[0059] SBZ8. Repeat steps SBZ1 to SBZ7 until the real-time speed N reaches or approaches the drive speed N';

[0060] SBZ9. When the real-time speed N reaches or approaches the driving speed N', switch to full voltage power supply.

[0061] SBL10. After the increasing process lasts for B, if the real-time speed N still does not reach or is close to the driving speed N', switch to full voltage power supply.

[0062] By using closed-loop control, PID algorithm and speed control to increase the supply voltage, this method provides an efficient, reliable and adaptable fan clutch control solution, which helps improve the performance of the entire cooling system and the overall operating efficiency of the vehicle. Specifically, it has the following beneficial effects:

[0063] Precise speed matching: The PID controller can fine-tune the fan supply voltage based on actual speed feedback, ensuring that the fan speed is precisely matched to the real-time needs of the engine.

[0064] Reduced startup shock: Since the PID algorithm can smoothly adjust the voltage, it reduces the shock when the fan starts and reduces the wear caused by rapid startup.

[0065] Reduced noise and vibration: Smooth speed control reduces noise and vibration during fan startup and operation, improving ride comfort.

[0066] Extended Equipment Life: By reducing fan clutch wear and shock, closed-loop control strategies help extend the life of the fan and its associated components.

[0067] Improve system stability: The integral action of the PID controller helps eliminate steady-state errors, and the differential action can predict and reduce system overshoot, thereby improving the stability of the entire system.

[0068] Adapt to different working conditions: The PID algorithm can dynamically adjust the control parameters according to different working conditions and engine loads, so that the system can adapt to different operating environments.

[0069] Enhanced fault tolerance: In the event of a sensor or actuator failure, the closed-loop control system can maintain operation by adjusting PID parameters or switching to an alternative control strategy, enhancing the system’s fault tolerance.

[0070] Improve system integration: Closed-loop control strategies can be integrated with other vehicle control systems to achieve more comprehensive monitoring and control.

[0071] Real-time monitoring and diagnosis: The closed-loop control system can monitor the operating status of the fan in real time and perform fault diagnosis and early warning by analyzing speed feedback.

[0072] 3. Another closed-loop control strategy:

[0073] Steps S1-S5 are the same as those in Embodiment 1, except that in step S6, gradually increasing the power supply voltage of the fan clutch uses a PID algorithm to increase the power supply voltage by speed control. The specific detailed steps include:

[0074] SBL1. Calculate the difference between the drive speed N' and the real-time speed N;

[0075] SBL2. Calculate the real-time rotation rate L and the calibrated rotation rate Lb, L=△N / △t, Lb=(N'-N) / B, △N is the rotation speed change value per unit time, △t is the unit time;

[0076] SBL3 calculates the difference between the real-time rotation rate L and the calibrated rotation rate Lb;

[0077] SBL4. Take the difference between L and Lb as the input of PID algorithm;

[0078] SBL5.PID algorithm calculates the output value based on the input difference and internal parameters;

[0079] SBL6 sends the output value as a duty cycle control signal to the PWM controller;

[0080] SBL8.PWM controller adjusts the supply voltage of the fan clutch electromagnetic coil according to the duty cycle control signal;

[0081] SBL8. Repeat steps SBL1 to SBL7 until the real-time speed N reaches or approaches the drive speed N ';

[0082] SBL9. When the real-time speed N reaches or approaches the driving speed N', switch to full voltage power supply.

[0083] SBL10. After the increasing process lasts for B, if the real-time speed N still does not reach or is close to the driving speed N', switch to full voltage power supply.

[0084] The closed-loop control strategy based on rotation speed control proposed in this embodiment has the following advantages compared with the simple rotation speed control in embodiment 2:

[0085] More sensitive response: RPM control focuses on the rate of change of speed, which makes the control system more sensitive and timely to changes in engine load.

[0086] Smooth Transition: By controlling the rate at which speed changes, speed control helps achieve smooth transitions in fan speed, reducing shock and wear caused by rapid acceleration or deceleration.

[0087] Improve system stability: By controlling the rate at which the speed changes, the system can operate more stably and reduce system oscillations that may be caused by rapid speed adjustments.

[0088] Improved control accuracy: The speed control can more accurately control the acceleration and deceleration process of the fan, achieving finer speed regulation.

[0089] Improve the flexibility of control logic: The speed control provides an additional adjustment dimension for the control system, and the calibrated speed can be flexibly set as needed to achieve specific control goals.

[0090] Reduced control lag: Speed ​​control helps reduce lag in the control process because the system can predict and respond to speed trends rather than just current speed deviations.

[0091] Enhance the predictive ability of the system: Through the derivative term, the PID controller can predict the future behavior of the system and make adjustments in advance to reduce overshoot and oscillation.

[0092] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. An electromagnetic fan clutch anti-wear and noise reduction device, comprising a vehicle-mounted control unit or an additional computing device (1), characterized in that: The vehicle-mounted control unit or the additional computing device (1) can calculate the driving speed of the fan clutch according to the real-time speed of the engine; and further comprises a current detection module (2), a PWM drive module (3) and a speed detection module (4) connected to the vehicle-mounted control unit or the additional computing device (1); when the electromagnetic fan clutch is a two-speed clutch, the ammeter (21) of the current detection module (2) and the MOSFET (31) of the PWM drive module (3) are connected in series to the power supply line (100) of the electromagnetic coil; when the electromagnetic fan clutch is a three-speed clutch, the ammeter (21) of the current detection module (2) and the MOSFET (31) of the PWM drive module (3) are connected in series to the power supply line (100) of the electromagnetic coil of the two coils that controls the clutch to directly drive at full speed; the speed sensor (41) of the speed detection module (4) is mounted on the shaft seat of the fan clutch.

2. The electromagnetic fan clutch anti-wear and noise reduction device according to claim 1, characterized in that: The computing device (1) is a single chip microcomputer.

3. The electromagnetic fan clutch anti-wear and noise reduction device according to claim 1, characterized in that: The real-time engine speed is obtained by reading data from the ECU or engine sensor.

4. The electromagnetic fan clutch anti-wear and noise reduction device according to claim 1, characterized in that: The drain of the MOSFET (31) is connected to the positive electrode of the power supply, the source is connected to the negative electrode of the power supply, and the gate is connected to the on-board control unit or the installed computing device (1).

5. The electromagnetic fan clutch anti-wear and noise reduction device according to claim 1, characterized in that: The rotation speed sensor (41) is a code disc and a Hall sensor.

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