Engine oil pump displacement control method and system

Abstract

The present disclosure relates to an oil pump displacement control method and system, belonging to the vehicle field, which can finely adjust the displacement of the oil pump and improve the lubrication efficiency and energy utilization rate. An oil pump displacement control method, the oil pump includes a drive motor and a displacement adjustment mechanism, the output shaft of the drive motor continuously rotates from one extreme position to another extreme position to steplessly adjust the rotation angle of the drive motor, and the rotational movement of the drive motor drives the displacement adjustment mechanism to move to adjust the displacement output by the displacement adjustment mechanism. The method includes: detecting the current oil pressure of the engine main oil passage; obtaining the current operating condition of the engine; determining the target oil pressure of the engine main oil passage under the current operating condition of the engine based on the mapping relationship between the engine speed, engine load and engine main oil passage oil pressure; calculating the difference between the current oil pressure and the target oil pressure; and adjusting the rotation angle of the drive motor based on the difference to adjust the displacement output by the displacement adjustment mechanism.

Description

Technical Field

[0001] The present disclosure relates to the field of vehicles, and more particularly, to an oil pump displacement control method and system. Background Art

[0002] In order to achieve the compactness of the engine, in the field of oil pump design, gears or belts with a fixed transmission ratio to the crankshaft speed are often used, which is called a fixed-displacement oil pump. When designing an oil pump, in order to ensure the oil pressure requirement at engine idle speed, the oil pressure at high engine speeds will far exceed the engine requirement. Therefore, a pressure relief valve is often designed at the oil pump outlet to avoid excessive oil pressure. Since the oil pump has already done work on the relieved oil, energy waste will occur here. Summary of the Invention

[0003] The object of the present disclosure is to provide an oil pump displacement control method and system, which can finely adjust the displacement of the oil pump, improve the lubrication efficiency and energy utilization rate, and improve the engine efficiency.

[0004] According to a first embodiment of the present disclosure, there is provided an oil pump displacement control method. The oil pump includes a drive motor and a displacement adjustment mechanism. The output shaft of the drive motor continuously rotates from one extreme position to another extreme position to steplessly adjust the rotation angle of the drive motor. The rotational movement of the drive motor drives the displacement adjustment mechanism to move to adjust the displacement output by the displacement adjustment mechanism. The method includes: detecting the current oil pressure in the main oil passage of the engine; obtaining the current operating condition of the engine; determining the target oil pressure in the main oil passage of the engine under the current operating condition of the engine based on the mapping relationship between the engine speed, the engine load, and the oil pressure in the main oil passage of the engine; calculating the difference between the current oil pressure and the target oil pressure; and adjusting the rotation angle of the drive motor based on the difference to adjust the displacement output by the displacement adjustment mechanism.

[0005] Optionally, the adjusting the rotation angle of the drive motor based on the difference includes: if the difference does not exceed a first difference, keeping the rotation angle of the drive motor unchanged; if the difference is between the first difference and a second difference, controlling the rotation angle of the drive motor to perform a micro-adjustment so that the difference is adjusted to not exceed the first difference; if the difference exceeds the second difference, determining the target rotation angle of the drive motor at the current engine speed and the target oil pressure based on the mapping relationship between the engine speed, the oil pressure in the main oil passage of the engine, and the rotation angle of the drive motor, controlling the drive motor to quickly rotate to the target rotation angle of the drive motor, and controlling the drive motor to perform a micro-adjustment near the target rotation angle of the drive motor so that the difference is adjusted to not exceed the first difference.

[0006] Optionally, a first difference when the vehicle is in a sport mode is greater than the first difference when the vehicle is in an economy mode, and a second difference when the vehicle is in the sport mode is greater than the second difference when the vehicle is in the economy mode.

[0007] Optionally, when the total driving mileage of the vehicle is less than a preset mileage or the vehicle is in a cold start condition, compared with the condition where the total driving mileage is greater than the preset mileage and the vehicle is in a normal operating state of non-cold start, at the same engine speed and the same engine load, the corresponding engine main oil passage oil pressure is higher.

[0008] Optionally, the method further includes: performing a drive motor angle zeroing operation in an engine operating condition where the drive motor angle zeroing operation needs to be performed, the engine operating condition where the drive motor angle zeroing operation needs to be performed being engine stable idle speed, zero load, water temperature greater than a preset water temperature, and the interval mileage between the current total driving mileage of the vehicle and the total driving mileage of the vehicle at the time of the last drive motor angle zeroing operation being greater than a preset interval mileage, wherein the drive motor angle zeroing operation includes: controlling the angle of the drive motor to rotate to a zero point angle determined at the time of the last drive motor angle zeroing operation; measuring an actual oil pressure average value in the engine main oil passage within a certain time at the zero point angle; calculating a difference between the actual oil pressure average value and the target oil pressure of the engine main oil passage in the engine operating condition where the drive motor angle zeroing operation needs to be performed; if the difference is greater than a third difference, controlling the drive motor to rotate to adjust the displacement output by the displacement adjustment mechanism so that the difference between the actual oil pressure in the engine main oil passage and the target oil pressure of the engine main oil passage in the engine operating condition where the drive motor angle zeroing operation needs to be performed does not exceed the third difference, and determining the current drive motor angle as a new zero point angle.

[0009] Optionally, the actual total rotatable angle of the drive motor is less than the total rotatable angle of the drive motor restricted by the structure of the displacement adjustment mechanism.

[0010] Optionally, the method further includes: performing a fault detection on the mechanism for detecting the current oil pressure of the engine main oil passage; in the case of detecting a fault, determining the target oil pressure of the engine main oil passage in the current engine operating condition according to the mapping relationship between the engine operating condition and the engine main oil passage oil pressure; determining a target drive motor angle at the current engine speed and the target oil pressure based on the mapping relationship between the engine speed, the engine main oil passage oil pressure and the drive motor angle; and controlling the drive motor to rotate to the target drive motor angle.

[0011] Optionally, the method further includes: detecting a fault in the drive motor and its transmission; in the case of detecting a fault, determining the current engine speed at the current engine main oil passage pressure and the current drive motor rotation angle according to the mapping relationship between the engine speed, the engine main oil passage pressure and the drive motor rotation angle; based on the mapping relationship between the engine speed, the engine load and the engine main oil passage pressure, determining the target engine load at the current engine speed and the current engine main oil passage pressure; and determining a preset percentage of the target engine load as the maximum allowable engine load in the case of an oil pump fault state.

[0012] According to a second embodiment of the present disclosure, there is provided an oil pump displacement control system, the oil pump displacement control system including an oil pressure detector, a controller and an oil pump. The oil pump includes a drive motor and a displacement adjustment mechanism. The output shaft of the drive motor continuously rotates from one extreme position to another extreme position to steplessly adjust the rotation angle of the drive motor. The rotational movement of the drive motor drives the displacement adjustment mechanism to move to adjust the displacement output by the displacement adjustment mechanism, wherein: the oil pressure detector is configured to detect the current oil pressure of the engine main oil passage; the controller is configured to obtain the current operating condition of the engine, determine the target oil pressure of the engine main oil passage under the current operating condition of the engine based on the mapping relationship between the engine speed, the engine load and the engine main oil passage pressure, calculate the difference between the current oil pressure and the target oil pressure, and based on the difference, adjust the rotation angle of the drive motor to adjust the displacement output by the displacement adjustment mechanism.

[0013] Optionally, the power transmission mechanism of the displacement adjustment mechanism adopts a worm structure and has a self-locking characteristic so that the movement of the displacement adjustment mechanism is not transmitted to the drive motor.

[0014] By adopting the above technical solution, since the output shaft of the drive motor can continuously rotate from one extreme position to another extreme position to steplessly adjust the rotation angle of the drive motor, it is possible to steplessly adjust the displacement output by the displacement adjustment mechanism based on the difference between the current oil pressure and the target oil pressure of the engine main oil passage, that is, it is possible to achieve fine adjustment of the oil pump displacement, make the engine main oil passage pressure adapt to the engine operating condition, improve the lubrication efficiency and energy utilization rate, and improve the engine efficiency.

[0015] Other features and advantages of the present disclosure will be described in detail in the subsequent specific implementation section. Description of the Drawings

[0016] The drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific implementation, they are used to explain the present disclosure, but do not constitute a limitation to the present disclosure. In the drawings:

[0017] Figure 1 is a flowchart of an oil pump displacement control method according to an embodiment of the present disclosure.

[0018] Figure 2 Shows a schematic diagram of an exemplary mapping relationship among engine speed, engine load, and engine main oil gallery oil pressure.

[0019] Figure 3 Shows another schematic diagram of an exemplary mapping relationship among engine speed, engine load, and engine main oil gallery oil pressure.

[0020] Figure 4 Shows a schematic diagram of the mapping relationship among engine speed, engine main oil gallery oil pressure, and driving motor rotation angle.

[0021] Figure 5 is a schematic block diagram of an oil pump displacement control system according to an embodiment of the present disclosure. Detailed Embodiments

[0022] The following further elaborates on the detailed embodiments of the present disclosure with reference to the accompanying drawings. It should be understood that the detailed embodiments described herein are only for the purpose of illustration and explanation of the present disclosure, and are not intended to limit the present disclosure.

[0023] Figure 1 is a flowchart of an oil pump displacement control method according to an embodiment of the present disclosure. The oil pump includes a driving motor and a displacement adjusting mechanism. The output shaft of the driving motor continuously rotates from one extreme position to another extreme position to steplessly adjust the rotation angle of the driving motor. The rotational movement of the driving motor drives the displacement adjusting mechanism to move to adjust the displacement output by the displacement adjusting mechanism. Moreover, the driving motor can rotate forward and backward, and the rotation of the driving motor can be transmitted to the displacement adjusting mechanism with a large reduction ratio, thereby realizing fine adjustment of the oil pump displacement. When the engine speed remains unchanged, when the driving motor rotates from one extreme position to another extreme position through continuous rotation, it respectively corresponds to the minimum performance and the maximum performance of the oil pump at this engine speed.

[0024] The oil pump displacement control method according to an embodiment of the present disclosure may include the following steps S11 to S15.

[0025] In step S11, detect the current oil pressure of the engine main oil gallery.

[0026] The oil pumped out by the oil pump directly or indirectly enters the engine main oil gallery, forming a certain pressure in the engine main oil gallery. The current oil pressure of the engine main oil gallery can be detected by various types of pressure sensors.

[0027] In step S12, obtain the current operating condition of the engine.

[0028] The current operating conditions of the engine may include the engine speed, engine load, and may also include the engine coolant temperature, etc.

[0029] In step S13, based on the mapping relationship between the engine speed, engine load, and the engine main oil gallery oil pressure, the target oil pressure of the engine main oil gallery under the current operating conditions of the engine is determined.

[0030] Figure 2 An exemplary mapping relationship diagram showing the engine speed, engine load, and the engine main oil gallery oil pressure is shown. It can be seen that at the same engine speed, the curve of the engine main oil gallery oil pressure varying with the engine load is a convex function.

[0031] Figure 3 Another exemplary mapping relationship diagram showing the engine speed, engine load, and the engine main oil gallery oil pressure is shown. It can be seen that at the same engine load, the curve of the engine main oil gallery oil pressure varying with the engine speed is a concave function.

[0032] Those skilled in the art should understand that Figure 2 and Figure 3 in, the specific numerical values of the engine speed, engine load, and the engine main oil gallery oil pressure are only examples and do not constitute a limitation to the present disclosure. In fact, for different engine models and different engine main oil gallery structures, Figure 2 and Figure 3 the specific numerical values of the engine speed, engine load, and the engine main oil gallery oil pressure in will also change accordingly, but the overall trend of the mapping relationship will not change.

[0033] In step S14, the difference between the current oil pressure and the target oil pressure is calculated.

[0034] In step S15, based on the difference, the rotation angle of the drive motor is adjusted to adjust the displacement output by the displacement adjustment mechanism.

[0035] By adopting the above technical solution, since the output shaft of the drive motor can continuously rotate from one extreme position to another extreme position to steplessly adjust the rotation angle of the drive motor, it is possible to steplessly adjust the displacement output by the displacement adjustment mechanism based on the difference between the current oil pressure and the target oil pressure of the engine main oil gallery, that is, it is possible to achieve fine adjustment of the oil pump displacement, make the engine main oil gallery oil pressure adapt to the engine operating conditions, improve the lubrication efficiency and energy utilization rate, and improve the engine efficiency.

[0036] In some embodiments, the adjusting the rotation angle of the drive motor based on the difference mentioned in step S15 may include:

[0037] If the difference between the current oil pressure and the target oil pressure in the engine main oil passage does not exceed the first difference, the rotation angle of the drive motor is kept unchanged. In this case, there is no need to adjust the oil pump displacement.

[0038] If the difference between the current oil pressure and the target oil pressure in the engine main oil passage is between the first difference and the second difference, control the rotation angle of the drive motor for fine adjustment so that the difference is adjusted to not exceed the first difference. That is, in this case, the displacement output by the displacement adjustment mechanism is finely adjusted by determining the fine adjustment of the motor rotation angle, thereby achieving fine adjustment of the displacement.

[0039] If the difference between the current oil pressure and the target oil pressure in the engine main oil passage exceeds the second difference, then:

[0040] First, based on the mapping relationship among the engine speed, the engine main oil passage oil pressure, and the drive motor rotation angle, determine the target rotation angle of the drive motor at the current engine speed and the target oil pressure. Figure 4 Show a schematic diagram of the mapping relationship among the engine speed, the engine main oil passage oil pressure, and the drive motor rotation angle. As Figure 4 shown, at the same engine speed, the engine main oil passage oil pressure increases as the drive motor rotation angle increases. In the figure, the drive motor rotation angle is illustrated by taking the turbine of the oil pump moving 3 teeth and the worm rotating 3 circles as an example. In this case, according to the transmission ratio of 1:3, the total rotation range of the drive motor is about 3600 degrees. However, those skilled in the art should understand that Figure 4 in, the specific values of the engine speed, the engine main oil passage oil pressure, and the drive motor rotation angle are only examples and do not constitute a limitation to the present disclosure. In fact, different engine models, different engine main oil passage structures, and different drive motor models will all cause Figure 4 the specific values of the engine speed, the engine main oil passage oil pressure, and the drive motor rotation angle in to change, but the overall trend of the mapping relationship will not change.

[0041] Then, control the drive motor to quickly rotate to the target rotation angle of the drive motor.

[0042] Then, control the drive motor to perform fine adjustment near the target rotation angle of the drive motor so that the difference is adjusted to not exceed the first difference.

[0043] By adopting the above technical solution, by determining the target rotation angle of the drive motor based on the mapping relationship and controlling the drive motor to quickly rotate to the target rotation angle of the drive motor, a rough and rapid adjustment of the rotation angle of the drive motor and thus the displacement output by the displacement adjustment mechanism is achieved. Then, by controlling the drive motor to perform fine adjustment near the target rotation angle of the drive motor, fine adjustment of the rotation angle of the drive motor and fine adjustment of the displacement output by the displacement adjustment mechanism are achieved. Through the combination of rough and rapid adjustment and fine adjustment, the displacement can be adjusted quickly and the fine adjustment of the displacement can be realized.

[0044] In some embodiments, for different vehicle operating conditions, the specific values of the above first difference and second difference may also be different.

[0045] For example, for a new vehicle and an engine after major overhaul, it is necessary to ensure sufficient lubrication of the engine during the running-in period, or for a vehicle in a cold start operating condition, it is also necessary to ensure sufficient lubrication of the engine during the cold start operating condition (i.e., during the warm-up period). For this purpose, it is necessary to ensure that the oil pressure in the main oil passage of the engine under the running-in condition and the oil pressure in the main oil passage of the engine under the cold start operating condition are higher than the oil pressure in the main oil passage of the engine under other normal operating conditions (referred to as normal conditions) other than running-in and cold start, at the same engine speed and the same engine load. For example, assume that under the running-in condition, based on the mapping relationship, the target oil pressure in the main oil passage of the engine corresponding to an engine speed of 700 rpm and an engine load of 60% is 5. Then, the target oil pressure in the main oil passage of the engine determined based on the mapping relationship under normal conditions should be less than 5, such as 4 or other values less than 5.

[0046] In the present disclosure, it can be defined that the situation where the total driving mileage of the vehicle is less than a preset mileage (e.g., 2000 km) is the running-in period of the engine.

[0047] In the present disclosure, it can be defined that if the water temperature of the engine after the first start is lower than a preset water temperature (e.g., 70 °C), it is called a cold start operating condition.

[0048] In addition, in order to meet the driving experience and usage requirements of different consumer groups, automatic transmission models are generally designed with a sport mode, an economy mode, and other modes.

[0049] For the sport mode, due to the delayed upshift, relatively high engine speed and low load scenarios are more commonly adopted to increase the responsiveness of vehicle speed. This technology adjusts the throttle response sensitivity, with rapid working condition switching and increased regulation frequency of the oil pump. To reduce the regulation frequency of the oil pump, a relatively high engine main oil gallery oil pressure mapping relationship and a high threshold adjustment mode can be adopted, that is, the values of the first difference and the second difference in the sport mode can be greater than those in other modes. For example, assuming that the first difference is 5 kPa and the second difference is 10 kPa in other modes, the first difference and the second difference in the sport mode can be set larger, such as 10 kPa and 30 kPa respectively.

[0050] For the economy mode, to achieve sufficient fuel-saving effect and reduce the throttle response sensitivity, it is necessary to deeply step on the throttle to increase fuel injection. The engine operating conditions are relatively stable and the condition switching is gentle. Therefore, a refined low-threshold adjustment mode can be adopted in the economy mode, that is, the first difference and the second difference in the economy mode can be smaller than those in other modes. For example, assuming that the first difference and the second difference are 10 kPa and 30 kPa respectively in other modes, the first difference and the second difference in the economy mode can be 5 kPa and 10 kPa respectively.

[0051] In this way, different first differences and second differences can be set for different working conditions to better meet the engine working condition requirements, improve the lubrication efficiency and energy utilization rate, and enhance the engine efficiency.

[0052] In some embodiments, factors such as particle deposition on the oil filter will affect the oil pressure in the engine main oil gallery. Additionally, if the oil pressure in the engine main oil gallery needs to be adjusted, the adjustment angle of the drive motor rotation angle will be calculated based on the current actual oil pressure and the target oil pressure estimated according to the mapping relationship. By continuously adjusting the drive motor rotation angle, the oil pressure in the engine main oil gallery can be made to adapt to the operating conditions. However, during the actual operation process, due to mechanical and angle counting principle factors, there may be a discrepancy between the calculated adjustment rotation angle and the actual rotation angle, which is also known as "out-of-step". "Out-of-step" does not affect the actual oil pressure in the engine main oil gallery because the actual oil pressure in the engine main oil gallery is monitored by the oil pressure detector and adjusted in real time according to the working conditions. However, the long-term accumulation of "out-of-step" will cause the "zero point" position of the drive motor rotation angle to drift, making the adjustment process of the oil pressure in the engine main oil gallery more complex.

[0053] For the above reasons, it is necessary to regularly calibrate the "zero" position of the drive motor's rotation angle. Therefore, the method according to the embodiments of the present disclosure may further include: performing a drive motor rotation angle zeroing operation (i.e., zero position calibration operation) under an engine condition where a drive motor rotation angle zeroing operation needs to be performed. The engine condition where a drive motor rotation angle zeroing operation needs to be performed is that the engine is in stable idle, zero load, the water temperature is greater than a preset water temperature (e.g., 70 °C), and the interval mileage between the current total vehicle mileage and the total vehicle mileage at the time of the last drive motor rotation angle zeroing operation is greater than a preset interval mileage.

[0054] In some embodiments, the drive motor rotation angle zeroing operation may include: controlling the rotation angle of the drive motor to rotate to the zero rotation angle determined at the time of the last drive motor rotation angle zeroing operation; measuring the average actual oil pressure in the engine main oil passage within a certain time at the zero rotation angle; calculating the difference between the average actual oil pressure and the target oil pressure of the engine main oil passage under the engine condition where a drive motor rotation angle zeroing operation needs to be performed; if the difference is greater than a third difference, controlling the drive motor to rotate to adjust the displacement output by the displacement adjustment mechanism so that the difference between the actual oil pressure in the engine main oil passage and the target oil pressure of the engine main oil passage under the engine condition where a drive motor rotation angle zeroing operation needs to be performed does not exceed the third difference, and determining the current drive motor rotation angle as the new zero rotation angle. In this way, the zero calibration of the drive motor rotation angle can be achieved.

[0055] The third difference is smaller than the first difference described above, so as to be able to perform zero calibration more accurately. For example, the third difference can be set to 2 kPa or a smaller value.

[0056] In addition, before the next drive motor rotation angle zeroing operation is completed, the rotation angle position of this time will be used as the zero point, and the drive motor rotation angles used in non-zeroing operations will all start from the zero position obtained by the zero calibration operation as zero degrees. After the engine stops, the rotation angle of the drive motor returns to the zero point and waits for the next start.

[0057] In some embodiments, the actual total rotatable angle A of the drive motor 有效 is less than the total rotatable angle A of the drive motor restricted by the structure of the displacement adjustment mechanism 总 . The total rotatable angle A of the drive motor restricted by the structure of the displacement adjustment mechanism 总 is also called the hard limit, and the actual total rotatable angle A of the drive motor 有效 is also called the soft limit implemented at the software level. Since the "zero" position of the drive motor is set inside the interval of the actual total rotatable angle A of the drive motor 有效 , therefore, based on the zero point, the rotatable control angle interval of the drive motor is [-A 下限 , A 上限, and satisfy the condition |A 下限 | + |A 上限 | = A 有效 (A 下限 、A 上限 are both greater than 0), that is, the drive motor is only allowed to rotate within this range. By such configuration, irreversible damage to the drive motor caused by hard limit operation can be avoided.

[0058] In some embodiments, when the engine power supply is initially turned on, a self-check is performed to check whether the system functions are normal; during operation, the operating parameters of the system are also monitored. If an abnormality is detected, a fault code is reported and the fault mode is entered.

[0059] Based on this, the oil pump displacement control method according to an embodiment of the present disclosure may further include: performing a fault detection on the mechanism (such as an oil pressure detector) for detecting the current oil pressure of the engine main oil passage; in the case of detecting a fault, determining the target oil pressure of the engine main oil passage under the current operating condition of the engine according to the mapping relationship between the engine operating condition and the oil pressure of the engine main oil passage, for example, determining the target oil pressure of the engine main oil passage under the current operating condition of the engine based on the mapping relationship between the engine speed, the engine load and the oil pressure of the engine main oil passage; then, determining the target rotation angle of the drive motor at the current engine speed and the target oil pressure based on the mapping relationship between the engine speed, the oil pressure of the engine main oil passage and the rotation angle of the drive motor; and controlling the drive motor to rotate to the target rotation angle of the drive motor.

[0060] That is, if a fault is detected in the mechanism for detecting the current oil pressure of the engine main oil passage, the oil pump displacement will be controlled in an open loop manner, that is, directly controlling the drive motor to rotate to the target rotation angle of the drive motor, and no longer performing micro-adjustment based on the difference between the target oil pressure and the actual oil pressure.

[0061] By adopting the above technical solution, it is possible to effectively adjust the oil pump displacement even when a fault occurs in the mechanism for detecting the current oil pressure of the engine main oil passage, ensuring the lubrication and efficiency of the engine.

[0062] In addition to detecting faults in the oil pressure detector, faults in the drive motor and its transmission are also detected. Therefore, the method according to an embodiment of the present disclosure may further include: detecting faults in the drive motor and its transmission; in the case of detecting a fault, determining the current engine speed at the current engine main oil passage pressure and the current drive motor rotation angle according to the mapping relationship between the engine speed, the engine main oil passage pressure, and the drive motor rotation angle; determining the target engine load at the current engine speed and the current engine main oil passage pressure based on the mapping relationship between the engine speed, the engine load, and the engine main oil passage pressure; and determining a preset percentage of the target engine load as the maximum allowable engine load in the case of an oil pump fault state.

[0063] That is, in the case of detecting a fault in the drive motor or its transmission (which also means that the oil pump has a fault), open-loop control is performed on the oil pump displacement. Moreover, since the oil pump regulating device is stuck in this case and its current function is similar to that of a fixed-displacement pump, the system will only allow the engine to operate at a preset percentage (e.g., 80%) of the maximum load allowed by the oil pump performance at the stuck position. That is to say, due to the fault of the oil pump, the faulty oil pump will limit the maximum allowable engine load. Through the above technical solution, the maximum allowable engine load in the case of an oil pump fault state (such as the above-mentioned target engine load) can be determined, and the actual operating load of the engine is restricted based on the maximum allowable engine load in the case of an oil pump fault state, ensuring the safe operation of the engine.

[0064] Figure 5 It is a schematic block diagram of an oil pump displacement control system according to an embodiment of the present disclosure. As Figure 5 shown, the oil pump displacement control system includes an oil pressure detector 10, a controller 20, and an oil pump 30.

[0065] The oil pump 30 includes a drive motor and a displacement regulating mechanism. The output shaft of the drive motor continuously rotates from one extreme position to the other extreme position to steplessly adjust the rotation angle of the drive motor. The rotational movement of the drive motor drives the displacement regulating mechanism to move to adjust the displacement output by the displacement regulating mechanism. Moreover, the drive motor can rotate forward and backward, and the rotation of the drive motor can be transmitted to the displacement regulating mechanism with a large reduction ratio, thereby realizing fine adjustment of the oil pump displacement. When the engine speed remains unchanged, when the output shaft of the drive motor rotates from one extreme position to the other extreme position through continuous rotation, it respectively corresponds to the minimum performance and the maximum performance of the oil pump at this engine speed.

[0066] The oil pressure detector 10 is used to detect the current oil pressure of the engine main oil passage. The oil pressure detector 10 may be a pressure sensor.

[0067] The controller 20 is configured to obtain the current operating condition of the engine, determine the target oil pressure of the engine main oil passage under the current operating condition of the engine based on the mapping relationship among the engine speed, the engine load, and the engine main oil passage oil pressure, calculate the difference between the current oil pressure and the target oil pressure, and based on the difference, adjust the rotation angle of the drive motor to adjust the displacement output by the displacement adjustment mechanism.

[0068] By adopting the above technical solution, since the output shaft of the drive motor can continuously rotate from one extreme position to the other extreme position to steplessly adjust the rotation angle of the drive motor, it is possible to steplessly adjust the displacement output by the displacement adjustment mechanism based on the difference between the current oil pressure and the target oil pressure of the engine main oil passage, that is, it is possible to achieve fine adjustment of the oil pump displacement, make the engine main oil passage oil pressure adapt to the engine operating condition, improve the lubrication efficiency and energy utilization rate, and improve the engine efficiency.

[0069] Optionally, the power transmission mechanism of the displacement adjustment mechanism adopts a worm structure and has a self-locking characteristic so that the movement of the displacement adjustment mechanism will not be transmitted to the drive motor. That is, the rotational movement of the drive motor can be transmitted to the displacement adjustment mechanism, and the movement of the displacement adjustment mechanism cannot be transmitted to the drive motor due to self-locking.

[0070] Optionally, the adjusting the rotation angle of the drive motor based on the difference includes: if the difference does not exceed the first difference, keeping the rotation angle of the drive motor unchanged; if the difference is between the first difference and the second difference, controlling the rotation angle of the drive motor for fine adjustment so that the difference is adjusted to not exceed the first difference; if the difference exceeds the second difference, determining the target rotation angle of the drive motor at the current engine speed and the target oil pressure based on the mapping relationship among the engine speed, the engine main oil passage oil pressure, and the drive motor rotation angle, controlling the drive motor to quickly rotate to the target rotation angle of the drive motor, and controlling the drive motor to perform fine adjustment near the target rotation angle of the drive motor so that the difference is adjusted to not exceed the first difference.

[0071] Optionally, the first difference when the vehicle is in the sports mode is greater than the first difference when the vehicle is in the economy mode, and the second difference when the vehicle is in the sports mode is greater than the second difference when the vehicle is in the economy mode.

[0072] Optionally, compared with the situation where the total driving mileage of the vehicle is greater than the preset mileage and the vehicle is in a normal operating state without cold start, when the total driving mileage of the vehicle is less than the preset mileage or the vehicle is in a cold start situation, at the same engine speed and the same engine load, the corresponding engine main oil passage oil pressure is higher.

[0073] Optionally, the controller is further configured to: in an engine operating condition where the zeroing operation of the drive motor angle needs to be performed, control the execution of the zeroing operation of the drive motor angle, where the engine operating condition where the zeroing operation of the drive motor angle needs to be performed is that the engine is in stable idle speed, zero load, the water temperature is greater than a preset water temperature, and the interval mileage between the current total vehicle mileage and the total vehicle mileage at the time of the last zeroing operation of the drive motor angle is greater than a preset interval mileage;

[0074] Wherein, the zeroing operation of the drive motor angle includes: controlling the rotation angle of the drive motor to rotate to the zero rotation angle determined at the time of the last zeroing operation of the drive motor angle; measuring the average actual oil pressure in the engine main oil passage within a certain time at the zero rotation angle; calculating the difference between the average actual oil pressure and the target oil pressure of the engine main oil passage in the engine operating condition where the zeroing operation of the drive motor angle needs to be performed; if the difference is greater than a third difference, controlling the drive motor to rotate to adjust the displacement output by the displacement adjusting mechanism so that the difference between the actual oil pressure in the engine main oil passage and the target oil pressure of the engine main oil passage in the engine operating condition where the zeroing operation of the drive motor angle needs to be performed does not exceed the third difference, and determining the current drive motor rotation angle as the new zero rotation angle.

[0075] Optionally, the actual total rotatable angle of the drive motor is less than the total rotatable angle of the drive motor restricted by the structure of the displacement adjusting mechanism.

[0076] Optionally, the oil pump displacement control system further includes a fault detection module for performing fault detection on the mechanism for detecting the current oil pressure in the engine main oil passage;

[0077] The controller is further configured to, in the case of detecting a fault, determine the target oil pressure of the engine main oil passage in the current engine operating condition according to the mapping relationship between the engine operating condition and the engine main oil passage oil pressure; determine the target drive motor rotation angle at the current engine speed and the target oil pressure based on the mapping relationship between the engine speed, the engine main oil passage oil pressure and the drive motor rotation angle; and control the drive motor to rotate to the target drive motor rotation angle.

[0078] Optionally, the oil pump displacement control system further includes a fault detection module for performing fault detection on the drive motor and its transmission device;

[0079] The controller is further configured to, when a fault is detected, determine the current engine speed at the current engine main oil gallery oil pressure and the current drive motor rotation angle according to the mapping relationship between the engine speed, the engine main oil gallery oil pressure and the drive motor rotation angle; determine the target engine load at the current engine speed and the current engine main oil gallery oil pressure based on the mapping relationship between the engine speed, the engine load and the engine main oil gallery oil pressure; and determine a preset percentage of the target engine load as the maximum allowable engine load in the case of an oil pump fault.

[0080] The specific implementation manners of the various modules in the oil pump displacement control system according to the embodiments of the present disclosure have been described in detail in the relevant methods and will not be elaborated herein.

[0081] The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0082] In addition, it should be noted that, in the case of no conflict, the various specific technical features described in the above specific implementation manners can be combined in any appropriate manner. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination manners.

[0083] In addition, any combination can be made between the various different embodiments of the present disclosure as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. An oil pump displacement control method, characterized in that, The oil pump includes a drive motor and a displacement adjustment mechanism. The output shaft of the drive motor adjusts the rotation angle of the drive motor steplessly by continuously rotating from one extreme position to the other extreme position. The rotational movement of the drive motor drives the displacement adjustment mechanism to move so as to adjust the displacement output by the displacement adjustment mechanism. The method includes: Detect the current oil pressure in the engine main oil passage; Obtain the current operating condition of the engine; Based on the mapping relationship among the engine speed, the engine load, and the oil pressure in the engine main oil passage, determine the target oil pressure in the engine main oil passage under the current operating condition of the engine; Calculate the difference between the current oil pressure and the target oil pressure; Based on the difference, adjust the rotation angle of the drive motor to adjust the displacement output by the displacement adjustment mechanism; The adjusting the rotation angle of the drive motor based on the difference includes: If the difference does not exceed a first difference, keep the rotation angle of the drive motor unchanged; If the difference is between the first difference and a second difference, control the rotation angle of the drive motor to perform a fine adjustment so that the difference is adjusted to not exceed the first difference; If the difference exceeds the second difference, then based on the mapping relationship among the engine speed, the oil pressure in the engine main oil passage, and the rotation angle of the drive motor, determine the target rotation angle of the drive motor at the current engine speed and the target oil pressure, control the drive motor to quickly rotate to the target rotation angle of the drive motor, and control the drive motor to perform a fine adjustment near the target rotation angle of the drive motor so that the difference is adjusted to not exceed the first difference.

2. The method according to claim 1, wherein The first difference when the vehicle is in the sport mode is greater than the first difference when the vehicle is in the economy mode, and the second difference when the vehicle is in the sport mode is greater than the second difference when the vehicle is in the economy mode.

3. The method according to claim 1, wherein Compared with the situation where the total driving mileage of the vehicle is less than a preset mileage or the vehicle is in a cold start situation, and the situation where the total driving mileage is greater than the preset mileage and the vehicle is in a normal operating state of non-cold start, under the same engine speed and the same engine load, the corresponding oil pressure in the engine main oil passage is higher.

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: Under the engine condition where the rotation angle of the drive motor needs to be reset to zero, perform the operation of resetting the rotation angle of the drive motor. The engine condition where the rotation angle of the drive motor needs to be reset to zero is that the engine is in stable idle speed, zero load, the water temperature is greater than a preset water temperature, and the interval mileage between the current total driving mileage of the vehicle and the total driving mileage of the vehicle at the time of the last operation of resetting the rotation angle of the drive motor is greater than a preset interval mileage. Among them, the operation of resetting the rotation angle of the drive motor includes: Control the rotation angle of the drive motor to rotate to the zero rotation angle determined at the time of the last operation of resetting the rotation angle of the drive motor; Measure the average actual oil pressure in the engine main oil passage within a certain time at the zero rotation angle; Calculate the difference between the average actual oil pressure and the target oil pressure in the engine main oil passage under the engine condition where the rotation angle of the drive motor needs to be reset to zero; If the difference is greater than the third difference, control the driving motor to rotate to adjust the displacement output by the displacement adjusting mechanism, so that the difference between the actual oil pressure in the engine main oil passage and the target oil pressure in the engine main oil passage under the engine operating condition where the driving motor rotation angle needs to be reset to zero does not exceed the third difference, and determine the current driving motor rotation angle as the new zero rotation angle.

5. The method according to any one of claims 1 to 3, characterized in that The actual total rotatable angle of the driving motor is less than the total rotatable angle of the driving motor restricted by the structure of the displacement adjusting mechanism.

6. The method according to any one of claims 1 to 3, characterized in that The method further includes: Performing a fault detection on the mechanism for detecting the current oil pressure in the engine main oil passage; In the case of detecting a fault, determining the target oil pressure in the engine main oil passage under the current engine operating condition according to the mapping relationship between the engine operating condition and the oil pressure in the engine main oil passage; Based on the mapping relationship between the engine speed, the oil pressure in the engine main oil passage, and the driving motor rotation angle, determining the target rotation angle of the driving motor at the current engine speed and the target oil pressure; and Controlling the driving motor to rotate to the target rotation angle of the driving motor.

7. The method according to any one of claims 1 to 3, characterized in that, The method further includes: Performing a fault detection on the driving motor and its transmission device; In the case of detecting a fault, determining the current engine speed at the current oil pressure in the engine main oil passage and the current rotation angle of the driving motor according to the mapping relationship between the engine speed, the oil pressure in the engine main oil passage, and the driving motor rotation angle; Based on the mapping relationship between the engine speed, the engine load, and the oil pressure in the engine main oil passage, determining the target engine load at the current engine speed and the current oil pressure in the engine main oil passage; Determining a preset percentage of the target engine load as the maximum allowable engine load in the case of an oil pump fault.

8. An oil pump displacement control system, characterized in that, The oil pump displacement control system includes an oil pressure detector, a controller, and an oil pump. The oil pump includes a driving motor and a displacement adjusting mechanism. The output shaft of the driving motor continuously rotates from one extreme position to the other extreme position to steplessly adjust the rotation angle of the driving motor. The rotational movement of the driving motor drives the displacement adjusting mechanism to move to adjust the displacement output by the displacement adjusting mechanism, where: The oil pressure detector is used to detect the current oil pressure in the engine main oil passage; The controller is used to obtain the current engine operating condition, determine the target oil pressure in the engine main oil passage under the current engine operating condition based on the mapping relationship between the engine speed, the engine load, and the oil pressure in the engine main oil passage, calculate the difference between the current oil pressure and the target oil pressure, and based on the difference, adjust the rotation angle of the driving motor to adjust the displacement output by the displacement adjusting mechanism; The controller is used to adjust the rotation angle of the driving motor based on the difference in the following manner: If the difference does not exceed the first difference, keep the rotation angle of the drive motor unchanged; if the difference is between the first difference and the second difference, control the rotation angle of the drive motor for fine adjustment so that the difference is adjusted to not exceed the first difference; if the difference exceeds the second difference, based on the mapping relationship between the engine speed, the engine main oil gallery oil pressure and the drive motor rotation angle, determine the target rotation angle of the drive motor at the current engine speed and the target oil pressure, control the drive motor to quickly rotate to the target rotation angle of the drive motor, and control the drive motor to perform fine adjustment near the target rotation angle of the drive motor so that the difference is adjusted to not exceed the first difference.

9. The system according to claim 8, wherein The power transmission mechanism of the displacement adjustment mechanism adopts a worm structure and has a self-locking characteristic so that the movement of the displacement adjustment mechanism will not be transmitted to the drive motor.

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