Method for monitoring wear of an engine friction pair and vehicle

Abstract

The application provides a kind of engine friction pair wear monitoring method and vehicle, it is related to vehicle control technical field, the method comprises: when vehicle travels with pure electric drive mode, the vibration acceleration of vehicle is obtained;According to vibration acceleration, the cumulative damage of engine is determined;When cumulative damage is greater than or equal to preset cumulative damage, control oil pump to operate for preset length of time;When oil pump starts, cumulative damage is zeroed.Control oil pump to operate for preset length of time, make a certain amount of oil to be transported to friction pair by oil pump, on the one hand, flush the particles generated at friction pair, on the other hand, reconstruct oil film on the surface of shaft and the inner surface of bearing bush at friction pair, improve lubrication environment, to avoid dry friction between shaft and bearing bush, it is beneficial to prolong the service life of engine.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, and more specifically, to a method for monitoring the wear of engine friction pairs and a vehicle. Background Technology

[0002] In existing hybrid vehicles, the engine does not operate when running in pure electric mode. However, when the car travels over uneven surfaces or speed bumps, the significant vibrations cause impacts to the engine. Prolonged exposure to these impacts without engine operation can damage the crankshaft oil film, deteriorating the lubrication environment of the engine's friction pairs and accelerating engine lifespan decline. Summary of the Invention

[0003] The problem that this invention aims to solve is that hybrid electric vehicles experience wear on the engine friction pairs when operating in pure electric mode.

[0004] To address the aforementioned problems, in a first aspect, the present invention provides a method for monitoring the wear of engine friction pairs, comprising:

[0005] When the vehicle is driving in pure electric mode, the vibration acceleration of the vehicle is acquired;

[0006] Based on the vibration acceleration, the cumulative damage to the engine is determined;

[0007] When the cumulative damage is greater than or equal to the preset cumulative damage, the oil pump is controlled to run for a preset time. When the oil pump starts, the current monitoring cycle ends, the cumulative damage is reset to zero, and the next monitoring cycle begins.

[0008] Optionally, determining the cumulative damage to the engine based on the vibration acceleration includes:

[0009] Based on the vibration acceleration, determine the single-shot damage value of the engine;

[0010] When the single damage value is greater than or equal to the preset single damage value, the oil pump is controlled to run for a preset time.

[0011] When the single damage value is less than the preset single damage value, the cumulative damage of the engine is determined based on all the single damage values ​​within the current monitoring period.

[0012] Optionally, when the single damage value is less than the preset single damage value, determining the cumulative damage of the engine based on all the single damage values ​​within the current monitoring period includes:

[0013] When the single damage value is less than the preset single damage value, all the single damage values ​​in the current monitoring period are added together to obtain the cumulative damage of the current monitoring period.

[0014] Optionally, the method for monitoring the wear of the engine friction pairs further includes:

[0015] Monitor the temperature of the engine oil and the duration of the temperature maintenance.

[0016] Based on the temperature, the duration of the temperature, and the viscosity-temperature curve of the engine oil, determine the cumulative return value of the engine oil within the current monitoring period;

[0017] When the accumulated return oil value is greater than or equal to the preset accumulated return oil value, the oil pump is controlled to run for a preset time. When the oil pump starts, the current monitoring cycle ends, the accumulated return oil value is reset to zero, and the next monitoring cycle begins.

[0018] Optionally, determining the cumulative oil return value of the engine oil within the current monitoring period based on the temperature, the duration of temperature maintenance, and the viscosity-temperature curve of the engine oil includes:

[0019] The oil return rate of the engine oil is determined based on the temperature and the viscosity-temperature curve.

[0020] Based on the oil return rate, determine the complete oil return time corresponding to the temperature;

[0021] The oil return completion rate for each temperature is determined based on the duration of temperature maintenance and the duration of complete oil return corresponding to the temperature.

[0022] The oil return completion rates of all items within the current monitoring period are summed to obtain the cumulative oil return value for the current monitoring period.

[0023] Optionally, the method for monitoring the wear of the engine friction pairs further includes:

[0024] When the vehicle is driving in pure electric drive mode, the continuous driving time of the vehicle is obtained;

[0025] When the continuous driving time is greater than or equal to the preset continuous driving time, the oil pump is controlled to run for a preset duration. When the oil pump starts, the current monitoring cycle ends, the continuous driving time is reset to zero, and the next monitoring cycle begins.

[0026] Optionally, the method for monitoring the wear of the engine friction pairs further includes:

[0027] When the vehicle is driving in pure electric drive mode, the continuous driving range of the vehicle is obtained;

[0028] When the continuous driving mileage is greater than or equal to the preset continuous driving mileage, the oil pump is controlled to run for a preset time. When the oil pump starts, the current monitoring cycle ends, the continuous driving mileage is reset to zero, and the next monitoring cycle begins.

[0029] Optionally, the method for monitoring the wear of the engine friction pairs further includes:

[0030] When the vehicle stops, obtain the duration of the vehicle's stop;

[0031] When the stop duration is greater than or equal to the preset stop duration and the vehicle starts, the oil pump is controlled to run for the preset duration.

[0032] When the vehicle starts moving, the stopping time is reset to zero.

[0033] Optionally, the method for monitoring the wear of the engine friction pairs further includes:

[0034] After the oil pump has been controlled to run for a preset time, monitor whether the vehicle has switched to fuel drive mode or hybrid drive mode.

[0035] When the vehicle switches to the fuel drive mode or the hybrid drive mode, the oil pump is controlled to continue operating.

[0036] When the vehicle is not switched to the fuel drive mode or the hybrid drive mode, the oil pump is controlled to stop.

[0037] Secondly, the present invention also provides a vehicle including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the above-mentioned method for monitoring the wear of engine friction pairs is implemented.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] This invention provides a method and vehicle for monitoring wear of engine friction pairs. When the vehicle is driving in pure electric drive mode, the engine is usually in a stopped state. Since the engine does not have a need to output power temporarily, the oil pump in the engine will not run actively. At this time, the lubricating oil at the friction pairs in the engine cannot be continuously replenished. By acquiring the vibration acceleration of the vehicle, the cumulative damage of the engine can be determined and continuously monitored. When the cumulative damage is greater than or equal to the preset cumulative damage, it indicates that the vibration generated by the vehicle operation has reached the limit value for the damage to the crankshaft or camshaft at the friction pairs in the engine. For example, the oil film on the crankshaft at the friction pairs may have been destroyed. Continued movement will cause wear to the crankshaft, and the fine particles that may be generated by the wear will also accelerate the damage to the crankshaft. At this time, it is necessary to control the oil pump to run for a preset time so that the oil pump delivers a certain amount of oil to the friction pairs. On the one hand, it washes away the particles generated at the friction pairs, and on the other hand, it rebuilds the oil film on the shaft surface and the inner surface of the bearing at the friction pairs, improves the lubrication environment, avoids dry friction between the shaft and the bearing, and helps to extend the service life of the engine. Attached Figure Description

[0040] Figure 1 A schematic flowchart of a method for monitoring the wear of engine friction pairs based on cumulative damage is shown in an embodiment of the present invention.

[0041] Figure 2 A schematic flowchart of a method for monitoring the wear of engine friction pairs based on the cumulative value of oil return is shown in an embodiment of the present invention.

[0042] Figure 3 A schematic diagram of the viscosity-temperature curve of the engine oil in an embodiment of the present invention is shown;

[0043] Figure 4 A schematic flowchart of a method for monitoring the wear of engine friction pairs based on continuous driving time is shown in an embodiment of the present invention.

[0044] Figure 5 A schematic flowchart of a method for monitoring the wear of engine friction pairs based on continuous driving mileage is shown in an embodiment of the present invention.

[0045] Figure 6 A schematic diagram of a monitoring system for monitoring the wear of engine friction pairs according to an embodiment of the present invention is shown;

[0046] Figure 7 A schematic diagram of the structure of a vehicle according to an embodiment of the present invention is shown. Detailed Implementation

[0047] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0048] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0049] In the description of this specification, references to terms such as "embodiment," "one embodiment," and "one implementation" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or implementation is included in at least one embodiment or implementation of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or implementation. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or implementations.

[0050] Figure 1 A schematic flowchart of a method for monitoring the wear of engine friction pairs according to an embodiment of the present invention is shown. The method for monitoring the wear of engine friction pairs includes:

[0051] S1: When the vehicle is driving in pure electric mode, obtain the vibration acceleration of the vehicle.

[0052] Specifically, in existing new energy vehicles, the engine remains stationary during pure electric operation unless additional control is applied. When the engine is not running for an extended period, the mechanical oil pump also stops working, failing to supply lubricating oil to the engine. While the car is traveling on the road in pure electric mode, some of the vibrations transmitted from the road surface are transmitted to the engine through the wheels, suspension, chassis, and engine mounts, causing engine vibration. This vibration is particularly pronounced when the car travels over uneven surfaces (such as speed bumps), where the impact on the engine is greater, increasing the amplitude of engine vibration. When the engine vibrates, the crankshaft and camshaft, due to inertia, will experience wear on their friction pairs. The vibrations of a vehicle's engine are unpredictable, requiring real-time monitoring of every vibration. For some plug-in hybrid electric vehicles (PHEVs) or range-extended hybrid electric vehicles (REEVs), vibration acceleration sensors are installed near the vehicle body or engine. When the sensor is mounted on a vehicle mount (e.g., the front frame), the collected vibration acceleration is the vehicle's vibration acceleration; when mounted on the engine, it is the engine's vibration acceleration. To ensure measurement accuracy, it's preferable to mount the sensor on the engine. However, if mounting the sensor on the engine is inconvenient, it can be mounted on the vehicle mount. Because the engine is fixed to the vehicle mount (e.g., the front frame), its vibration acceleration changes with the vehicle's vibration acceleration. Since the variation patterns of vehicle and engine vibration acceleration are essentially the same, the vehicle's vibration acceleration can be equated to the engine's vibration acceleration. This data is then uploaded to the vehicle's VCU (Vehicle Control Unit), allowing direct access to the vibration acceleration at each data collection point.

[0053] S2: Determine the cumulative damage to the engine based on the vibration acceleration.

[0054] Specifically, multiple vibration accelerations of the engine can be continuously collected using accelerometers or other measuring devices. The vibration acceleration data is then subjected to Fourier transform to obtain a frequency domain representation, and the power spectral density (PSD) is calculated. The PSD represents the energy distribution at different frequencies and can be used to describe the spectral characteristics of the vibration signal. Depending on the specific application requirements, appropriate fatigue damage indices are selected, such as the Rainflow counting method or the Miner linear cumulative damage method. Based on the fatigue damage indices and the PSD, corresponding calculations can be performed to obtain the fatigue damage value of the engine crankshaft or camshaft at each vibration occurrence, and thus the cumulative damage over a period of time can be obtained.

[0055] S3: When the accumulated damage is greater than or equal to the preset accumulated damage, control the oil pump to run for a preset time. When the oil pump starts, the current monitoring cycle ends, the accumulated damage is reset to zero, and the next monitoring cycle begins. Therefore, the start of the oil pump is an important indicator for dividing the two monitoring cycles.

[0056] Specifically, cumulative damage is monitored. When the cumulative damage reaches a preset level, it indicates that the combined number and force of collisions between the crankshaft and bearings have reached a certain level. After such frequent collisions, the oil film on the crankshaft may have been damaged. Continued operation will cause wear on the crankshaft. The fine particles that may be generated by wear also need to be cleaned away from between the crankshaft and bearings in a timely manner. At this time, the movement of the oil pump needs to be controlled. When the oil pump moves, it will pump lubricating oil to the friction pairs on the engine crankshaft or camshaft. The lubricating oil will fill the space between the crankshaft and bearings, flush away the fine particles that may be generated by wear, lubricate the crankshaft and bearings where the friction pairs are located, improve the lubrication environment, reduce friction, and re-establish an oil film on the crankshaft surface, thereby extending the lubrication effect, enhancing the protection of the crankshaft, and helping to extend the service life of the engine. In addition, when controlling the operation of the oil pump, if the oil pump is a mechanical oil pump, then it is necessary to control the engine to run idle without ignition to drive the oil pump; if the oil pump is an electric oil pump, then it is not necessary to control the engine, but only to power the electric oil pump to control the electric oil pump to run independently.

[0057] When the oil pump starts, the current monitoring cycle ends, indicating that the lubricating oil at the friction pair has been replenished in time, the lubrication environment of the friction pair has stopped deteriorating, and the oil film on the surface of the crankshaft and camshaft has been rebuilt. Therefore, it is necessary to reset the cumulative damage of the engine to zero and enter the next monitoring cycle to continuously monitor the cumulative damage of the engine in order to achieve the circulation control of the oil pump.

[0058] In this embodiment, when the vehicle is driving in pure electric drive mode, the engine does not have a need to output power temporarily, and the oil pump in the engine will not operate actively. At this time, the lubricating oil at the friction pairs in the engine cannot be continuously replenished. By acquiring the vibration acceleration of the vehicle, the cumulative damage of the engine is determined and continuously monitored. When the cumulative damage is greater than or equal to the preset cumulative damage, it indicates that the vibration generated by the vehicle operation has reached the limit of damage to the crankshaft or camshaft at the friction pairs in the engine. For example, the oil film on the crankshaft at the friction pairs may have been destroyed. Continued movement will cause wear to the crankshaft, and the fine particles that may be generated by the wear will also accelerate the damage to the crankshaft. At this time, it is necessary to control the oil pump to run for a preset time so that the oil pump delivers a certain amount of oil to the friction pairs. On the one hand, it washes away the particles generated at the friction pairs, and on the other hand, it rebuilds the oil film on the shaft surface and the inner surface of the bearing at the friction pairs, improves the lubrication environment, avoids dry friction between the shaft and the bearing, and helps to extend the service life of the engine.

[0059] In one embodiment of the present invention, determining the cumulative damage of the engine based on the vibration acceleration includes:

[0060] The single-shot damage value of the engine is determined based on the vibration acceleration.

[0061] Specifically, during the pure electric driving process of a car, in addition to monitoring cumulative damage, it is also necessary to analyze each vibration acceleration collected separately and monitor the single damage value of the engine under each vibration acceleration. When the vibration impact is large, although the cumulative damage does not exceed the standard, a single vibration may destroy the oil film built between the crankshaft and the bearing. Therefore, it is necessary to monitor the moment when the single damage value is large.

[0062] When the single damage value is greater than or equal to the preset single damage value, the oil pump is controlled to run for a preset time.

[0063] Specifically, when the single-damage value exceeds the preset single-damage value (i.e., the single-damage value exceeds the standard), it indicates that the car may be passing through a section of road with poor road conditions. The vibration amplitude caused by the car on this section of road is large, resulting in severe engine bumps and a large impact force between the crankshaft and bearing. This increases the probability of generating wear particles and the possibility of instantaneous damage to the oil film. In order to ensure a good lubrication environment at the engine friction pairs, it is necessary to control the oil pump to run for a period of time to replenish the friction pairs with oil in a timely manner and improve the lubrication environment.

[0064] When the single damage value is less than the preset single damage value, the cumulative damage of the engine is determined based on all the single damage values ​​within the current monitoring period.

[0065] Specifically, the cumulative damage for the current monitoring period is obtained by summing all the single damage values ​​within the current monitoring period. This indicates that since the last oil pump start-up, all single damage values ​​analyzed within the current monitoring period are less than a preset single damage value. These values ​​are then summed. When the single damage value remains below the preset single damage value, it indicates that the car is traveling on a smooth road with minimal bumps and the engine is not experiencing strong impacts. In this case, the oil film will gradually wear down until the cumulative damage reaches a certain level and the oil film is destroyed. Only then is the oil pump controlled to avoid frequent start-stop or continuous operation of the oil pump, reducing the number of oil pump operations and the total operating time, thus ensuring the service life of the oil pump.

[0066] In one embodiment of the present invention, such as Figure 2 As shown, the method for monitoring the wear of the engine friction pairs further includes:

[0067] S50: Monitor the temperature of the engine oil and the duration of the temperature maintenance.

[0068] Specifically, sometimes vehicles travel on flat roads for extended periods, ensuring that even when driven in pure electric mode for long periods, the cumulative damage remains less than the preset cumulative damage. However, the fluid in the vehicle continuously flows from higher to lower levels due to gravity. When a significant amount of oil accumulates at the lower levels, it flows back to the oil pan or recovery box. Meanwhile, the oil at the friction surfaces gradually decreases over time. When all the oil has returned to the recovery box, the friction surfaces are unlubricated. If vibration occurs, the friction surfaces will be in a state of dry friction, accelerating the wear of engine shaft parts. Therefore, it is necessary to monitor the time it takes for the oil to completely return. However, the oil return speed is greatly affected by the oil temperature. Figure 3 As shown, as the oil temperature increases, its kinematic viscosity decreases and the oil return speed increases. Since the ambient temperature of the engine may change at any time, the engine temperature is not a constant value, which leads to the oil temperature being inconsistent. Therefore, it is necessary to obtain the oil temperature and the duration of this temperature.

[0069] S51: Determine the cumulative oil return value of the engine oil within the current monitoring cycle based on the temperature, the duration of the temperature maintenance, and the viscosity-temperature curve of the engine oil.

[0070] Specifically, the oil return rate can be determined by analyzing the temperature and the viscosity-temperature curve of the engine oil. By analyzing the oil return rate and the duration of temperature maintenance, the oil return flow rate at that temperature can be calculated. Then, by calculating the oil return volume corresponding to the temperature over multiple time periods within the current monitoring cycle, the total oil return volume can be calculated. The accumulated oil return value is the ratio of the total oil return volume to the maximum amount of engine oil temporarily stored at the friction pair.

[0071] S52: When the accumulated oil return value is greater than or equal to a preset accumulated oil return value, the oil pump is controlled to run for a preset time. When the oil pump starts, the current monitoring cycle ends, the accumulated oil return value is reset to zero, and the next monitoring cycle begins. The oil return status is then re-accumulated and monitored, enabling cyclical monitoring of the oil return status at the friction pair.

[0072] Specifically, when the total oil return exceeds the amount of oil that can be temporarily stored between the shaft and bearing, it indicates that the oil at the friction pair has completely returned. The preset oil return accumulation value can be set to 1, indicating complete oil return; alternatively, it can be set to 0.9, where the oil pump briefly runs to replenish oil when there is very little remaining, effectively preventing dry friction between the shaft and bearing. Furthermore, when the vehicle is running, vibrations cause the lubricating oil previously stored between the friction pairs (crankshaft and bearing, camshaft and camshaft bearing housing, etc.) to flow back to the oil pan at an accelerated rate, further reducing oil availability and accelerating fretting wear. In this case, the oil return accumulation value can be set even lower, for example, to 0.6, to improve the control sensitivity of the oil pump and reduce the probability of dry friction at the friction pairs.

[0073] In this embodiment, the friction pair wear monitoring method based on accumulated return oil value and the friction pair wear monitoring method based on accumulated damage in the above embodiments can be carried out in parallel. That is, within a monitoring cycle, both accumulated damage and accumulated return oil value can be monitored simultaneously. When the car is driving on a flat road, the accumulated return oil value may reach the preset accumulated return oil value first. At this time, it indicates that there is not much oil left at the friction pair. The oil pump can be controlled to increase the amount of oil in the friction pair and ensure the lubrication environment. However, when the car is driving on a bumpy road, the accumulated damage may reach the preset accumulated damage first. This indicates that on a bumpy road, due to the strong impact between the shaft and the bearing shell or bearing housing, the oil film at the friction pair is damaged and cannot protect the shaft. In addition, due to the strong impact, some small particles may also accumulate at the friction pair due to impact wear. At this time, it is necessary to control the oil pump to deliver oil to the friction pair. On the one hand, it washes away the small particles from the friction pair. On the other hand, it is also to rebuild a good oil film on the shaft surface to improve the lubrication environment at the friction pair. By simultaneously monitoring cumulative damage and return oil accumulation, the friction pairs inside the engine can be protected in a timely and effective manner regardless of the vehicle's driving conditions. This enhances the vehicle's monitoring method's adaptability to the environment and improves control accuracy and sensitivity.

[0074] In one embodiment of the present invention, determining the cumulative oil return value of the engine oil within the current monitoring period based on the temperature, the duration of temperature maintenance, and the viscosity-temperature curve of the engine oil includes:

[0075] The oil return rate of the engine oil is determined based on the temperature and the viscosity-temperature curve.

[0076] Specifically, from Figure 3 As can be seen, at the same temperature, the kinematic viscosity of mineral oil is lower than that of synthetic oil. Therefore, after determining the type of engine oil, the corresponding viscosity-temperature curve is determined. Based on the temperature, the kinematic viscosity value can be determined from the viscosity-temperature curve, and thus the oil return speed can be obtained. Different kinematic viscosities correspond to different oil return speeds, which can be determined by looking up a pre-stored correspondence table. Figure 3 It can be seen that as the temperature increases, the kinematic viscosity decreases, and the corresponding oil return speed increases.

[0077] Based on the oil return rate, determine the complete oil return time corresponding to the temperature.

[0078] Specifically, based on the oil return speed and the maximum amount of oil that can be stored at the friction pair, the time required for all the oil to return at the current oil return speed can be determined and recorded as the complete oil return time corresponding to the current temperature.

[0079] The oil return completion rate for each temperature is determined based on the duration of temperature maintenance and the duration of complete oil return corresponding to the temperature.

[0080] For example, such as Figure 3 At each temperature T, there is a corresponding kinematic viscosity v. Each kinematic viscosity v corresponds to a return oil rate and a complete return oil time t. For example, at temperature T1, it takes t1 minutes for complete return oil. If the oil only stays at that temperature for t1' minutes, then the degree of return oil completion is:

[0081] r = t1' / t1.

[0082] The oil return completion rates of all items within the current monitoring period are summed to obtain the cumulative oil return value for the current monitoring period.

[0083] Specifically, such as Figure 3 Calculate the return oil completion rate for T1, T2, and T3 respectively, and then sum the return oil completion rates to obtain the cumulative return oil value:

[0084]

[0085] Where R is the cumulative return oil value, t i Oil temperature T i The corresponding complete oil return time, t i 'T represents the engine oil temperature T' i The duration of maintenance, where i is the i-th data collected in the current monitoring cycle. When the cumulative return oil value is zero, i can also be zero.

[0086] In one embodiment of the present invention, such as Figure 4 The method for monitoring wear of engine friction pairs further includes:

[0087] S60: When the vehicle is driving in pure electric drive mode, obtain the continuous driving time of the vehicle.

[0088] S61: When the continuous driving time is greater than or equal to a preset continuous driving time, the oil pump is controlled to run for a preset duration. When the oil pump starts, the current monitoring cycle ends, the continuous driving time is reset to zero, and the next monitoring cycle begins, thus realizing cyclical monitoring of the continuous driving time.

[0089] Specifically, when a vehicle travels on pure electric power for an extended period, even on a smooth road, the engine oil at the friction surfaces will continuously flow back. Vibration can further accelerate this backflow. Furthermore, engine vibrations exacerbate the breakdown of the oil film due to collisions between the shaft and bearing bush or bearing housing. Therefore, a preset continuous driving time can be set. If the vehicle continues to drive in pure electric mode for longer than this preset time, the oil pump will briefly activate. This control method is simple and has a fast response, but its accuracy, compatibility, and flexibility are limited, making it unsuitable for varying driving conditions. Additionally, the aforementioned continuous driving time does not refer to continuous driving without stopping, but rather the duration of multiple consecutive pure electric driving sessions. As long as hybrid mode is not interrupted during pure electric driving, it can be counted as continuous driving time.

[0090] In this embodiment, the friction pair wear monitoring method based on continuous driving time and the friction pair wear monitoring method based on cumulative damage in the above embodiments can be performed simultaneously. Within a monitoring cycle, both cumulative damage and continuous driving time are monitored at the same time. When the car is driving on a flat road, it takes a long time for cumulative damage to accumulate to reach the preset cumulative damage. However, before the cumulative damage reaches the preset cumulative damage, the oil at the friction pair has already completely flowed back to the recovery box, and the friction pair is in a dry friction state. At this time, the preset continuous driving time can make the oil pump run at intervals to prevent the friction pair in the engine from being in a dry friction state for a long time. The preset continuous driving time is an estimated time for complete oil return based on experience or experiments, and can be adaptively adjusted according to the daily driving conditions of the vehicle. The friction pair wear monitoring method based on continuous driving time is a regular trigger control, and the friction pair wear monitoring method based on continuous driving time is a special case trigger control superimposed on the regular trigger control. When the regular trigger occurs before the special case trigger occurs, the special case will not be triggered. Only when the special case trigger occurs before the regular trigger will the special case trigger be executed. Combining the two methods simplifies control and saves analysis resources, while also taking into account the special circumstances of strong impacts on bumpy road sections, thus improving control accuracy.

[0091] Similarly, friction pair wear monitoring methods based on continuous driving time can be used in parallel with those based on accumulated oil return values. While the control precision of the continuous driving time-based method is lower, its control program is simpler, requires less computation, and has a faster response time. The accumulated oil return value-based method can precisely monitor the time point when the oil completely returns to the friction pair, offering higher control precision. However, if the vehicle is driven in winter or in low-temperature environments, the oil return rate is slower, and the interval between triggering the oil pump operation by the accumulated oil return value-based method is longer. During prolonged operation, a large amount of fine particles accumulate at the friction pair. Since flushing cannot wait until the oil has completely returned, the continuous driving time-based method will generate a control signal to activate the oil pump, pumping oil to the friction pair to flush away the fine particles and ensure a proper lubrication environment.

[0092] In one embodiment of the present invention, such as Figure 5 The method for monitoring wear of engine friction pairs further includes:

[0093] S70: When the vehicle is driving in pure electric drive mode, obtain the continuous driving range of the vehicle.

[0094] S71: When the continuous driving mileage is greater than or equal to the preset continuous driving mileage, the oil pump is controlled to run for a preset time. When the oil pump starts, the current monitoring cycle ends, the continuous driving mileage is reset to zero, and the next monitoring cycle begins, thus realizing cyclic monitoring of the continuous driving mileage.

[0095] Specifically, similar to the above embodiments, the aforementioned continuous driving mileage refers to the mileage of multiple consecutive pure electric driving trips. As long as hybrid mode driving is not interrupted during pure electric driving, it can be counted as continuous driving time. When the vehicle is driven in pure electric mode for a long time, the oil at the friction pairs will continuously flow back. When the engine vibrates, the friction pairs will collide, causing the oil film to be crushed. A preset continuous driving mileage is set. When the vehicle's continuous driving mileage in pure electric mode exceeds this preset value, the oil pump is controlled to work briefly. The control method is simple, the response speed is fast, and the calculation is minimal.

[0096] The friction pair wear monitoring method based on continuous driving mileage in this embodiment is similar to the friction pair wear monitoring method based on continuous driving time. Both can regularly generate control signals to control the cyclical operation of the oil pump. This can overcome the limitations of road conditions in the friction pair wear monitoring method based on cumulative damage in the above embodiments, and also overcome the limitations of ambient temperature in the friction pair wear monitoring method based on accumulated return oil value in the above embodiments. At the same time, the control methods for continuous driving mileage and continuous driving time have simple internal logic, which is easy for users to understand. During vehicle use, users can adjust the preset continuous driving mileage and preset continuous driving time according to their own vehicle conditions to ensure the lubrication environment of the engine friction pairs.

[0097] In one embodiment of the present invention, the method for monitoring the wear of the engine friction pair further includes:

[0098] When the vehicle stops, obtain the duration of the vehicle's stop.

[0099] When the stop duration is greater than or equal to a preset stop duration and the vehicle starts moving, the oil pump is controlled to run for the preset duration. Specifically, when the vehicle starts moving, the stop duration is reset to zero to facilitate the start of the next monitoring cycle, thus achieving cyclical monitoring of the stop duration.

[0100] Specifically, when a car is parked for an extended period (e.g., more than 10 hours in a parking space), the engine is not running. During this time, the engine oil (lubricating oil) undergoes continuous backflow, resulting in thorough backflow at the friction surfaces. There may be no oil left at these surfaces, or only a small amount, insufficient to form a complete oil film between the shaft and bearings. If the vehicle is started and driven directly, the vibrations will cause engine vibration, leading to wear on the shaft and bearings. Therefore, after starting or during starting, the engine should be driven by an electric motor to idle, activating the mechanical oil pump to pump oil; or the electric oil pump can be directly controlled to pump oil. The timing during this period differs from that during vehicle operation and requires separate timing.

[0101] The monitoring methods described in the above embodiments can be used in combination, and multiple monitoring methods can be equipped on the same vehicle, enabling indirect monitoring of the friction pair status under various conditions. For example, the vehicle's continuous pure electric driving time and continuous pure electric driving mileage can be collected by the vehicle's VCU. When both the continuous pure electric driving time and / or continuous pure electric driving mileage reach preset values, and the vehicle still needs to continue driving, engine start control is initiated, thereby driving the oil pump to pump oil. When neither the continuous pure electric driving time nor the continuous pure electric driving mileage reaches the preset values ​​and no other engine start conditions are triggered (i.e., the vehicle does not need to switch from pure electric driving mode to other driving modes), engine start control is not initiated, thereby keeping the oil pump stationary.

[0102] This invention addresses the issue of fretting wear on the friction pairs of engines in plug-in hybrid electric vehicles (PHEVs) and range-extended hybrid electric vehicles (REEVs) caused by random vibrations and impacts during prolonged pure electric driving. This invention does not require any changes to the original engine structure; it only adjusts the control method to reduce or even eliminate the wear problem of the internal friction pairs in PHEV and REEV engines. Existing vehicles can be upgraded by updating the control method, improving engine reliability without significantly increasing costs.

[0103] In one embodiment of the present invention, the method for monitoring the wear of the engine friction pair further includes:

[0104] After the oil pump has been running for a preset time, monitor whether the vehicle has switched to fuel drive mode or hybrid drive mode.

[0105] When the vehicle switches to the fuel drive mode or the hybrid drive mode, the oil pump is controlled to continue operating.

[0106] When the vehicle is not switched to the fuel drive mode or the hybrid drive mode, the oil pump is controlled to stop.

[0107] In this embodiment, for example, when the vehicle is running in pure electric mode, if the driver suddenly accelerates, but pure electric operation cannot meet the short-term acceleration needs, the engine needs to assist in acceleration. At this time, the vehicle enters hybrid drive mode, and the vehicle actively controls the engine to run. When the engine is running, it drives the oil pump to pump oil. Therefore, the control signal for the oil pump to run briefly for a preset duration is overridden by the control signal sent by the vehicle's hybrid driving needs. The engine continues to run until the driver completes the acceleration or decelerates, and the hybrid drive mode is no longer needed, switching back to pure electric mode. At this time, the engine stops, and the oil pump stops. Similarly, when the vehicle switches to fuel drive mode, the engine still needs to run, and the oil pump also needs to keep running continuously. Therefore, after controlling the oil pump to run for a preset duration, it is necessary to monitor whether the vehicle switches driving modes. When switching from pure electric driving mode to the other two driving modes, the engine and oil pump will be actively driven. Only when the vehicle does not need to switch driving modes will the oil pump be controlled to stop after running for the preset duration.

[0108] In one embodiment of the present invention, the method for monitoring the wear of the engine friction pair further includes:

[0109] The performance parameters of the oil in the oil pump are obtained, wherein the performance parameters include oil temperature, oil type, oil dilution degree and oil quality.

[0110] The preset values ​​used during monitoring are adjusted according to the performance parameters of the engine oil.

[0111] In this embodiment, for example, the oil return speed is also affected by the characteristics of the engine oil itself. Engine oil with better high-temperature fluidity results in a faster oil return speed. Therefore, preset values ​​such as preset cumulative damage, preset cumulative oil return value, preset continuous driving time, and preset continuous driving mileage can be adjusted according to the type of engine oil. The better the fluidity of the engine oil, the smaller the preset value. For example, the oil return speed is also affected by the degree of engine oil dilution (some engines have an oil quality sensor that can measure this data); the greater the oil dilution, the faster the oil return speed. Therefore, preset values ​​such as preset cumulative damage, preset cumulative oil return value, preset continuous driving time, and preset continuous driving mileage can be adjusted according to the degree of engine oil dilution. The greater the oil dilution, the smaller the preset value. For example, the oil return speed is also affected by the quality of the engine oil (some engines have an oil quality sensor that can measure this data). Theoretically, the longer the engine oil has been used, the more impurities it contains, and the lower its quality. Therefore, preset values ​​such as preset cumulative damage, preset cumulative oil return value, preset continuous driving time, and preset continuous driving mileage can be adjusted according to the engine oil quality. The lower the oil quality, the smaller the preset value.

[0112] Figure 6 This diagram illustrates a structural schematic of an engine friction pair wear monitoring system according to an embodiment of the present invention. The engine friction pair wear monitoring system includes:

[0113] The acquisition module 10 is used to acquire the vibration acceleration of the vehicle when the vehicle is driving in pure electric drive mode.

[0114] The analysis module 20 is used to determine the single damage value of the engine based on the vibration acceleration; and is also used to determine the cumulative damage of the engine based on all the single damage values ​​within the current monitoring period.

[0115] Control module 30 is used to control the oil pump to run for a preset time when the cumulative damage is greater than or equal to the preset cumulative damage.

[0116] The analysis module 20 is also used to reset the accumulated damage to zero and enter the next monitoring cycle when the oil pump starts, at the end of the current monitoring cycle.

[0117] In this embodiment, when the vehicle is driving in pure electric drive mode, the engine does not have a need to output power temporarily, and the oil pump in the engine will not run actively. At this time, the lubricating oil at the friction pair in the engine cannot be continuously replenished. The vibration acceleration of the vehicle is acquired by the acquisition module 10, and the analysis module 20 analyzes and determines the cumulative damage of the engine and continuously monitors the cumulative damage. When the cumulative damage is greater than or equal to the preset cumulative damage, it means that the vibration generated by the vehicle operation has reached the limit value for the damage to the crankshaft or camshaft at the friction pair in the engine. For example, the oil film on the crankshaft at the friction pair may have been destroyed. Continued movement will cause wear to the crankshaft, and the fine particles that may be generated by the wear will also accelerate the damage to the crankshaft. At this time, the control module 30 controls the oil pump to run for a preset time so that the oil pump delivers a certain amount of oil to the friction pair. On the one hand, it washes away the particles generated at the friction pair, and on the other hand, it rebuilds the oil film on the shaft surface and the inner surface of the bearing at the friction pair, improves the lubrication environment, avoids dry friction between the shaft and the bearing, and helps to extend the service life of the engine. In addition, when the oil pump is started, the analysis module 20 resets the accumulated damage to zero, thereby realizing cyclic monitoring of the accumulated damage.

[0118] Figure 7 A schematic diagram of a vehicle structure according to an embodiment of the present invention is shown. The vehicle includes a memory 100, a processor 200, and a computer program stored in the memory 100 and executable on the processor 200. When the processor 200 executes the computer program, the above-mentioned method for monitoring the wear of engine friction pairs is implemented.

[0119] The technical effects of the vehicle-engine friction pair wear monitoring method or engine friction pair wear monitoring system described in this invention are similar, and will not be repeated here.

[0120] Program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof. These programming languages ​​include object-oriented programming languages—such as Java, Smalltalk, and C++—as well as conventional procedural programming languages—such as the "C" language or similar programming languages. In particular, Python, suitable for neural network computation, and platform frameworks based on TensorFlow, PyTorch, etc., can be used. The program code can execute within the processor of the user's vehicle, partially within the processor of the user's vehicle, as a standalone software package, partially on the user's vehicle, and partially on a remote computer or in the cloud. In cases involving remote computers or the cloud, the remote computer or cloud server can be connected to the user's vehicle via any type of network—including a local area network (LAN) or a wide area network (WAN).

[0121] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for monitoring wear of engine friction pairs, characterized in that, include: When the vehicle is driving in pure electric mode, the vibration acceleration of the vehicle is acquired; The cumulative damage to the engine is determined based on the vibration acceleration, including: determining the single damage value of the engine based on the vibration acceleration; when the single damage value is greater than or equal to a preset single damage value, controlling the oil pump to run for a preset time; when the single damage value is less than the preset single damage value, determining the cumulative damage to the engine based on all the single damage values ​​within the current monitoring period. When the cumulative damage is greater than or equal to the preset cumulative damage, the oil pump is controlled to run for a preset time. When the oil pump starts, the current monitoring cycle ends, the cumulative damage is reset to zero, and the next monitoring cycle begins. It also includes: monitoring the temperature of the engine oil and the duration of each temperature maintenance; Based on the temperature of the engine oil, the duration of the temperature maintenance, and the viscosity-temperature curve of the engine oil, determine the cumulative return value of the engine oil within the current monitoring cycle; When the accumulated return oil value is greater than or equal to the preset accumulated return oil value, the oil pump is controlled to run for a preset time. When the oil pump starts, the current monitoring cycle ends, the accumulated return oil value is reset to zero, and the next monitoring cycle begins.

2. The method for monitoring wear of engine friction pairs according to claim 1, characterized in that, When the single-instance damage value is less than the preset single-instance damage value, the cumulative damage of the engine is determined based on all the single-instance damage values ​​within the current monitoring period, including: When the single damage value is less than the preset single damage value, all the single damage values ​​in the current monitoring period are added together to obtain the cumulative damage of the current monitoring period.

3. The method for monitoring wear of engine friction pairs according to claim 1, characterized in that, The step of determining the cumulative oil return value of the engine oil within the current monitoring period based on the temperature, the duration of temperature maintenance, and the viscosity-temperature curve of the engine oil includes: The oil return rate of the engine oil is determined based on the temperature and the viscosity-temperature curve. Based on the oil return rate, determine the complete oil return time corresponding to the temperature; The oil return completion rate for each temperature is determined based on the duration of temperature maintenance and the duration of complete oil return corresponding to the temperature. The oil return completion rates of all items within the current monitoring period are summed to obtain the cumulative oil return value for the current monitoring period.

4. The method for monitoring wear of engine friction pairs according to claim 1, characterized in that, Also includes: When the vehicle is driving in pure electric drive mode, the continuous driving time of the vehicle is obtained; When the continuous driving time is greater than or equal to the preset continuous driving time, the oil pump is controlled to run for a preset duration. When the oil pump starts, the current monitoring cycle ends, the continuous driving time is reset to zero, and the next monitoring cycle begins.

5. The method for monitoring wear of engine friction pairs according to claim 1, characterized in that, Also includes: When the vehicle is driving in pure electric drive mode, the continuous driving range of the vehicle is obtained; When the continuous driving mileage is greater than or equal to the preset continuous driving mileage, the oil pump is controlled to run for a preset time. When the oil pump starts, the current monitoring cycle ends, the continuous driving mileage is reset to zero, and the next monitoring cycle begins.

6. The method for monitoring wear of engine friction pairs according to claim 1, characterized in that, Also includes: When the vehicle stops, obtain the duration of the vehicle's stop; When the stop duration is greater than or equal to the preset stop duration and the vehicle starts, the oil pump is controlled to run for the preset duration. When the vehicle starts, the current monitoring cycle ends, the stop duration is reset to zero, and the next monitoring cycle begins.

7. The method for monitoring wear of engine friction pairs according to any one of claims 1-6, characterized in that, Also includes: After the oil pump has been controlled to run for a preset time, monitor whether the vehicle has switched to fuel drive mode or hybrid drive mode. When the vehicle switches to the fuel drive mode or the hybrid drive mode, the oil pump is controlled to continue operating. When the vehicle is not switched to the fuel drive mode or the hybrid drive mode, the oil pump is controlled to stop.

8. A vehicle, characterized in that, The method includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements a method for monitoring the wear of engine friction pairs as described in any one of claims 1-7.

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