Engine rotation speed control method, device and vehicle

Abstract

The application provides an engine speed control method, device and vehicle, the method comprising: acquiring wheel angular acceleration, and determining wheel end noise of the vehicle based on the wheel angular acceleration; detecting environmental noise in a cabin; determining target noise perceived by a user according to the wheel end noise and the environmental noise; determining maximum noise speed of an engine based on the target noise; and controlling starting of the engine based on the maximum noise speed when starting the engine of the vehicle is required. The application determines target noise perceived by a user by detecting wheel end noise of the vehicle and environmental noise in a cabin, and then determines corresponding maximum noise speed of the engine, so that the speed of the engine can be controlled according to noise perceived by the user during actual driving of the vehicle, the masking effect of noise is fully utilized to improve power generation or power conservation, and thus economic efficiency and power performance are not lost.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and more particularly to engine speed control methods, devices, and vehicles. Background Technology

[0002] Currently, hybrid vehicles primarily control engine speed based on overall vehicle power requirements. The desired engine speed is calculated by real-time monitoring parameters such as vehicle speed, battery charge, and throttle opening. During this process, to ensure good noise, vibration, and harshness (NVH) performance, an NVH speed limit table is pre-set based on the quietest road conditions. This table limits the maximum engine speed at different vehicle speeds and throttle openings. Finally, the desired engine speed, after being limited by NVH speeds, is determined and output.

[0003] However, in actual driving, the noise level inside a vehicle is not fixed. In many cases, the noise inside the vehicle is quite high. Controlling the engine according to the preset NVH tachometer will result in the engine speed being limited when the vehicle is noisy. This will prevent the engine from fully utilizing the noise masking effect to increase power generation or power retention, thus causing a loss of economy and power. Summary of the Invention

[0004] The main objective of this invention is to provide an engine speed control method, device, and vehicle, which aims to solve the technical problem of controlling engine speed with actual noise during actual driving using existing methods.

[0005] To achieve the above objectives, the present invention proposes an engine speed control method, comprising: The wheel angular acceleration is obtained, and the wheel-end noise of the vehicle is determined based on the wheel angular acceleration; Detect ambient noise inside the cockpit; The target noise that the user can perceive is determined based on the wheel end noise and the ambient noise. The maximum noise speed of the engine is determined based on the target noise. When it is necessary to start the vehicle engine, the engine is started based on the maximum noise speed.

[0006] Optionally, determining the target noise that the user can perceive based on the wheel-end noise and the ambient noise includes: The first noise frequency of the engine noise, the second noise frequency of the wheel end noise, and the third noise frequency of the ambient noise are obtained. The weights corresponding to the wheel end noise and the ambient noise are determined based on the first noise frequency, the second noise frequency, and the third noise frequency. The target noise that the user can perceive is determined by weighted summation of the wheel end noise, the ambient noise, the weight corresponding to the wheel end noise, and the weight corresponding to the ambient noise.

[0007] Optionally, the engine speed control method further includes: Detect whether the vehicle is currently in navigation mode; If so, then obtain the navigation information of the navigation mode and the remaining power of the battery pack in the vehicle; Determine the first target battery level corresponding to the current moment in the navigation mode based on the navigation information; If the remaining battery power is less than the first target battery power, the engine start-up route is determined based on the navigation information; Within the engine starting section, the steps of acquiring wheel angular acceleration and determining the vehicle's wheel-end noise based on the wheel angular acceleration are performed.

[0008] Optionally, determining the engine start-up route based on the navigation information when the remaining battery power is less than the first target battery power includes: If the remaining power is less than the first target power, the target power generation required by the engine is determined based on the first target power and the remaining power. Based on the navigation information, the engine generates a first amount of electricity at a preset speed throughout the entire route. The preset speed is a speed at which the user will not perceive engine noise. If the first power generation is not less than the target power generation, the engine start-up route is determined based on the target power generation and the preset speed. If the first power generation is less than the target power generation, the entire route is determined to be an engine start-up route. Accordingly, the step of acquiring wheel angular acceleration and determining the vehicle's wheel-end noise based on the wheel angular acceleration during the engine start-up section includes: The entire route is divided into sections with different vehicle speeds based on the navigation information. Within each segment of the road with different vehicle speeds, the steps of obtaining wheel angular acceleration and determining the wheel-end noise of the vehicle based on the wheel angular acceleration are performed.

[0009] Optionally, determining the first target battery level corresponding to the current moment in the navigation mode based on the navigation information includes: The required battery power for the vehicle to travel to its destination in the navigation mode is determined based on the navigation information. Detects the minimum battery level set by the user when the vehicle reaches its destination; The first target battery level corresponding to the current moment in the navigation mode is determined based on the required battery level and the minimum required battery level.

[0010] Optionally, the engine speed control method further includes: Detect the current operating scenario of the vehicle; Under the condition that the current operating scenario is an extreme scenario, obtain the environmental pressure and environmental temperature; The first maximum power of the engine and the maximum output power that the vehicle can output are determined based on the ambient pressure and the ambient temperature. The second maximum power required by the battery pack is determined based on the maximum output power and the first maximum power. The second target power required for the battery pack is determined based on the second maximum power and the ambient temperature. If the second target charge is less than the remaining charge of the battery pack, the required power output of the engine is determined based on the charge difference between the second target charge and the remaining charge. The output power of the engine is determined based on the power reserve and the engine's base power at the maximum noise speed. The target speed of the engine is determined based on the output power and the maximum noise speed of the engine. The engine is controlled to operate based on the target speed.

[0011] Optionally, determining the target engine speed based on the output power and the maximum noise speed of the engine based on the target noise further includes: Obtain the output speed corresponding to the output power; When the output speed is greater than the maximum noise speed, the speed release coefficient of the engine under extreme conditions is determined based on the difference between the second target charge and the remaining charge. The target speed of the engine is determined based on the maximum noise speed and the speed contact coefficient.

[0012] Optionally, the engine speed control method further includes: The current mode, current operating scenario, and charging power required by the battery pack during pure electric operation of the vehicle are obtained. Obtain the engine's required navigation speed when the current mode is navigation mode, the extreme speed under the current scenario, and the charging speed corresponding to the charging capacity; The current mode of the vehicle, the current operating scenario, and the charging power required by the battery pack during vehicle operation determine the speed percentages corresponding to the maximum noise speed, the navigation speed, the charging speed, and the extreme speed, respectively. The vehicle's final speed is obtained by weighting the maximum noise speed, the navigation speed, the charging speed, and the extreme speed based on the speed ratio.

[0013] Furthermore, to achieve the above objectives, the present invention also provides an engine speed control device, comprising: A noise determination module is used to acquire wheel angular acceleration and determine the wheel-end noise of the vehicle based on the wheel angular acceleration. The noise determination module is also used to detect ambient noise in the cockpit; The noise determination module is also used to determine the target noise that the user can perceive based on the wheel end noise and the ambient noise; A speed determination module is used to determine the maximum noise speed of the engine based on the target noise. The speed determination module is also used to control the engine to start based on the maximum noise speed when the vehicle engine needs to be started.

[0014] In addition, to achieve the above objectives, the present invention also provides a vehicle, the vehicle comprising: a controller, an engine, and a battery pack; The controller is used to execute the engine speed control method described in any of the above descriptions.

[0015] This invention provides an engine speed control method, device, and vehicle. The method includes acquiring wheel angular acceleration and determining wheel-end noise based on the wheel angular acceleration; detecting ambient noise in the driver's cabin; determining a target noise perceptible to a user based on the wheel-end noise and the ambient noise; determining the maximum noise speed of the engine based on the target noise; and controlling the engine to start based on the maximum noise speed when the vehicle engine needs to be started. This invention determines the target noise perceptible to a user by detecting the wheel-end noise and ambient noise in the driver's cabin, and then determines the corresponding maximum noise speed of the engine. This allows for engine speed control based on the user-perceptible noise during actual vehicle operation, fully utilizing the noise masking effect to improve power generation or power retention, thereby mitigating economic and power losses. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the first embodiment of the engine speed control method of the present invention; Figure 2 This is a flowchart illustrating the second embodiment of the engine speed control method of the present invention; Figure 3 This is a schematic diagram of the first process of the third embodiment of the engine speed control method of the present invention; Figure 4 This is a schematic diagram of the second process of the third embodiment of the engine speed control method of the present invention; Figure 5 This is a schematic diagram of the third process of the third embodiment of the engine speed control method of the present invention; Figure 6 This is a schematic diagram of the first process of the fourth embodiment of the engine speed control method of the present invention; Figure 7 This is a schematic diagram of the second process of the fourth embodiment of the engine speed control method of the present invention; Figure 8 This is a flowchart illustrating the fifth embodiment of the engine speed control method of the present invention; Figure 9 This is a schematic diagram of the engine speed control device proposed in this invention.

[0019] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of the present invention and are not intended to limit the present invention.

[0021] To better understand the technical solution of the present invention, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments.

[0022] Reference Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the engine speed control method of the present invention. Based on Figure 1 The first embodiment of the engine speed control method of the present invention is presented.

[0023] In this embodiment, the engine speed control method includes: Step S10: Obtain the wheel angular acceleration and determine the wheel end noise of the vehicle based on the wheel angular acceleration; It should be understood that in this embodiment and the following embodiments, a controller inside the vehicle can be used as the execution subject. The controller can be connected to information acquisition components such as acceleration sensors and noise sensors to receive information collected by the acquisition components and control the engine speed according to the acquired information.

[0024] Understandably, in hybrid vehicles, engine speed control directly impacts NVH performance, fuel economy, and power. NVH limits on engine speed are typically based on the quietest road conditions, ignoring the masking effect of environmental noise such as road and wind noise on engine noise in actual driving environments. This results in engine speed being limited in noisy scenarios, failing to fully utilize the masking effect of environmental noise to improve power generation or battery capacity, thus causing a loss in fuel economy and power. Specifically, the NVH speed limit can be determined by using vehicle speed and throttle input to establish an NVH speed limit coefficient. The engine speed required to maintain battery charge under current driving conditions is then calculated, and further calculations are performed based on the NVH speed limit coefficient and the required engine speed for maintaining battery charge.

[0025] It should be noted that wheel angular acceleration is the angular acceleration value of a vehicle's wheel during rotation, and can be used to indirectly reflect the vibration intensity caused by road surface roughness. Wheel-end noise is the noise generated by the contact between the wheel and the ground during vehicle operation. Wheel-end noise can be calculated using the vehicle's wheel angular acceleration. For example, the greater the wheel angular acceleration, the faster the vehicle travels, and the greater the noise generated by the wheel vibration on the same wheel surface.

[0026] In practical implementation, the controller of a hybrid vehicle can detect wheel angular acceleration through acceleration sensors installed on the wheels, or it can determine wheel angular acceleration by detecting changes in wheel rotation speed using speed sensors inside the vehicle. Once the wheel angular acceleration is determined, the wheel-end noise can be determined based on a pre-stored mapping relationship between wheel angular acceleration and wheel-end noise. This mapping relationship reflects the correspondence between wheel angular acceleration and wheel-end noise. The greater the wheel-end angular acceleration, the stronger the vibration of the wheels caused by the road surface, and consequently, the greater the wheel-end noise.

[0027] Considering the different types of road surfaces, such as smooth, medium rough, and rough, when measuring the decibel value of wheel-end noise, the relationship between wheel angular acceleration and noise can be fitted using the least squares method or other regression methods based on wheel angular acceleration. Where N is the vehicle-end noise, acc is the vehicle's angular acceleration, and a and b are constants in the linear fitting.

[0028] Furthermore, once wheel-end noise is acquired, its accuracy can be assessed. For example, after fitting the model, confidence levels can be set to ensure that the noise decibel value falls within a preset range under a specific wheel angular acceleration. The confidence interval is:

[0029] Where MSE is the mean squared error; n is the number of samples; and k is the degrees of freedom, for example, the degrees of freedom for fitting a relationship is 2. This represents the average wheel angular acceleration. The mean squared error (MSE) is the average squared error of the regression model's predictions, used to measure the difference between the model's predicted and actual values. The MSE can be determined by calculating the error for each data point corresponding to wheel-end noise, then calculating the sum of the squared errors, and finally determining the MSE based on the sum of the squared errors.

[0030] If the calculated decibel value of the wheel-end noise is within the confidence interval, it is determined that the detected angular acceleration and the calculated wheel-end noise are not abnormal; if the calculated decibel value of the wheel-end noise is not within the confidence interval, it is determined that the measurement of the vehicle angular acceleration is abnormal or the calculation process of the wheel-end noise is abnormal.

[0031] Step S20: Detect ambient noise in the cockpit; It should be noted that ambient noise refers to noise within the cockpit caused by environmental factors. Ambient noise can include wind noise, tire noise, air conditioning noise, etc. Ambient noise can be perceived by users inside the cockpit. In practice, ambient noise can be collected in real time using noise sensors installed within the cockpit.

[0032] In the process of detecting environmental noise, it is also necessary to determine the accuracy of the detected noise. For example, in multiple measurements, should the environmental noise data show a certain degree of consistency, or should there be prominent outliers? The consistency of environmental noise refers to the range of variation between consecutive data points. This range of variation should be within a certain range and not be too large. Let's assume a threshold for the rate of change is set. ,but: ;in, This is the measured value of the ambient noise during the current cycle. This refers to the environmental noise measurement value from the previous period. The maximum environmental noise difference is used to maintain data consistency. For outlier detection, statistical methods can be used, such as analyzing historical data for each environmental noise data point based on parameters like the mean and standard deviation, to determine if it represents abnormal environmental noise.

[0033] Understandably, if the environmental noise meets the data consistency requirements and there are no outliers or outliers are removed, the accurate decibel value of the environmental noise for each period can be determined.

[0034] Step S30: Determine the target noise that the user can perceive based on the wheel end noise and the ambient noise; It should be noted that the target noise is the noise value actually perceived by the user after combining wheel-end noise and ambient noise. For example, if the wheel-end noise is greater than the ambient noise, the wheel-end noise can be used as the target noise; of course, if the ambient noise is greater than the wheel-end noise, the ambient noise can be used as the target noise.

[0035] In practice, the decibel values ​​of the vehicle's wheel-end noise and the ambient noise can be compared, and the noise with the higher decibel value can be selected as the target noise.

[0036] Step S40: Determine the maximum noise speed of the engine based on the target noise; It should be noted that the maximum noise speed is the highest speed at which the engine is allowed to operate while still generating noise. The noise generated at the maximum noise speed should be less than the target noise so that the target noise can mask the noise generated by the engine.

[0037] In practice, the mapping relationship between noise and speed can be preset inside the vehicle. When the target noise is determined, the maximum noise speed that the engine can produce can be determined by looking up the mapping relationship, using the target noise as a benchmark.

[0038] Furthermore, considering that engine speed regulation is real-time, there may be multiple different speeds in a short period of time. If the speed difference between the previous and next speeds is large in a short period of time, it will cause the engine to switch speeds continuously in a short period of time, resulting in unstable engine operation.

[0039] Therefore, in this embodiment, to prevent frequent fluctuations in engine speed, a filter can be set to smooth the noise speed, so as to control the smooth change of engine speed when frequent adjustments to engine speed are required. For example, if the maximum noise speed determined in the previous cycle is 2000 rpm, the maximum noise speed in the current cycle is 3000 rpm, and the maximum noise speed determined in the later cycle is 3000 rpm, then the maximum noise speed in the current cycle can be controlled to increase from 2000 rpm to 2500 rpm, and in the next cycle, the maximum noise speed can be controlled to increase from 2500 rpm to 3000 rpm.

[0040] Step S50: When it is necessary to start the vehicle engine, control the engine to start based on the maximum noise speed.

[0041] Understandably, when starting the vehicle engine, the target engine speed can be limited to a range no greater than the maximum noise level, and engine start-up can be controlled based on this limited speed. For example, a hybrid vehicle driving on a rough asphalt road has a wheel angular acceleration of 2.5 rad / s², and the calculated wheel-end noise is 68 decibels. Simultaneously, the in-vehicle noise sensor detects an ambient noise level of 62 decibels. Using the wheel-end noise as a baseline, the mapping between noise and engine speed is looked up, and the maximum noise level corresponding to 68 decibels is 3200 rpm. When the vehicle needs to start the engine for charging, the controller limits the engine's target speed to below 3200 rpm, ensuring that the engine noise does not exceed the ambient noise, thus not affecting the quiet experience for passengers.

[0042] This embodiment provides an engine speed control method. The method includes acquiring wheel angular acceleration and determining wheel-end noise of the vehicle based on the wheel angular acceleration; detecting ambient noise in the cockpit; determining a target noise perceptible to the user based on the wheel-end noise and the ambient noise; determining the maximum noise speed of the engine based on the target noise; and controlling the engine to start based on the maximum noise speed when the vehicle engine needs to be started. This embodiment determines the target noise perceptible to the user by detecting the wheel-end noise and ambient noise in the cockpit, and then determines the corresponding maximum noise speed of the engine. This allows for engine speed control based on the user-perceptible noise during actual vehicle operation, fully utilizing the noise masking effect to improve power generation or power retention, thereby minimizing losses in economy and power performance.

[0043] Based on the first embodiment of the engine speed control method of the present invention, a second embodiment of the engine speed control method of the present invention is proposed. (Refer to...) Figure 2 , Figure 2 This is a flowchart illustrating the second embodiment of the engine speed control method of the present invention.

[0044] In this embodiment, the engine speed control method further includes: Step S31: Obtain the first noise frequency of the engine noise, the second noise frequency of the wheel end noise, and the third noise frequency of the ambient noise.

[0045] It should be understood that in hybrid vehicles, the frequency distribution of ambient noise and wheel-end noise differs, the human ear's sensitivity to different frequencies of noise also varies, and the masking effect of different frequencies of noise on engine noise varies. Directly comparing wheel-end noise with ambient noise cannot accurately reflect the noise level actually perceived by the user. For example, low-frequency road noise has a weaker masking effect on high-frequency engine noise, while high-frequency wind noise may be more easily perceived.

[0046] It should be noted that the first noise frequency can be the main noise frequency range generated by the engine during operation, such as 200Hz to 800Hz, depending on the engine speed and number of cylinders. The second noise frequency can be the main frequency range of wheel-end noise, such as 100Hz to 400Hz, which is related to tire tread pattern and road surface roughness. The third noise frequency is the main frequency range of ambient noise, such as 500Hz to 2000Hz.

[0047] In practice, the engine noise can be acquired first, and then the first noise frequency of the engine noise, the second noise frequency of the wheel end noise, and the third noise frequency of the environmental noise can be extracted based on the waveform changes of the engine noise, wheel end noise, and environmental noise.

[0048] Step S32: Determine the weights corresponding to the wheel end noise and the ambient noise respectively based on the first noise frequency, the second noise frequency and the third noise frequency.

[0049] It should be noted that the weight is a proportional coefficient allocated to wheel-end noise and ambient noise when determining the target noise. Its value is dynamically determined based on the degree of matching between each noise frequency and the loudness curve of the human ear, as well as the mutual masking effect. For example, when the first noise frequency of the engine noise overlaps significantly with the third noise frequency of the ambient noise, the weight of the ambient noise should be set to be larger; when the first noise frequency of the engine noise overlaps significantly with the second noise frequency of the wheel-end noise, the weight of the ambient noise should be set to be larger.

[0050] In practice, the weights of wheel-end noise and environmental noise can be determined based on the relationships between the first noise frequency, the second noise frequency, and the third noise frequency, such as the degree of frequency overlap or the strength of the masking effect.

[0051] Step S33: Perform a weighted summation of the wheel end noise, the ambient noise, the weight corresponding to the wheel end noise, and the weight corresponding to the ambient noise to determine the target noise that the user can perceive.

[0052] Understandably, after determining the weights corresponding to wheel-end noise and ambient noise, a weighted sum can be directly applied to wheel-end noise, ambient noise, the weights corresponding to wheel-end noise, and the weights corresponding to ambient noise to obtain the target noise that the user can perceive. For example, a hybrid vehicle is driving on a highway with an engine speed of 2500 rpm, and the first noise frequency is determined to be 400 Hz. Wheel-end noise, caused by the rough road surface, has a second noise frequency of 300 Hz. The ambient noise detected by the in-vehicle noise sensor is mainly wind noise, with a third noise frequency of 1500 Hz. Analysis shows that the engine noise frequency is relatively close to the wheel-end noise frequency, resulting in a good masking effect, while it is far from the wind noise frequency, resulting in a poor masking effect. Therefore, the weight of wheel-end noise can be set to 0.8, and the weight of ambient noise to 0.2. If the wheel-end noise is 70 dB and the ambient noise is 60 dB, then the target noise is calculated as 70 × 0.8 + 60 × 0.2 = 68 dB.

[0053] In this embodiment, by dynamically adjusting the weights based on the frequency characteristics of engine noise, wheel-end noise, and ambient noise, the target noise that the user can perceive is calculated more accurately, making the determination of the upper limit of engine speed more reasonable.

[0054] Based on the first or second embodiment of the engine speed control method proposed in this invention, a third embodiment of the engine speed control method of this invention is proposed. (Refer to...) Figure 3 , Figure 3 This is a schematic diagram of the first process of the third embodiment of the engine speed control method of the present invention.

[0055] In this embodiment, the engine speed control method further includes: Step S01: Detect whether the vehicle's current mode is in navigation mode, the current mode including navigation mode and non-navigation mode; It should be understood that in hybrid vehicles, navigation may be set during driving. If engine start planning is not considered in conjunction with navigation information, it could lead to forced engine start at low speeds and in low-noise environments, causing a drastic deterioration in NVH (noise, vibration, and harshness); or premature engine start when the battery is fully charged, wasting fuel. Especially during long-distance driving, if the engine start timing is not planned in advance based on the remaining distance and target battery level, the engine may be forced to start in congested traffic after the battery is depleted, resulting in abrupt noise and low charging efficiency.

[0056] It should be noted that the current mode refers to whether the navigation system is used during vehicle operation, specifically including navigation mode and non-navigation mode. Navigation mode refers to the active state of the vehicle's navigation system, where the user can set the destination via the in-vehicle screen. In practice, whether the vehicle is currently in navigation mode can be determined by whether the user has activated navigation.

[0057] Step S02: If yes, then obtain the navigation information of the navigation mode and the remaining power of the battery pack in the vehicle.

[0058] It should be noted that navigation information may include the driving route, the length of each road segment, the speed limit for each road segment, the estimated average speed of traffic flow, and the remaining range to the destination. Remaining battery power is the current displayed battery charge, usually expressed as a percentage of state of charge (SOC). In practice, if the vehicle is confirmed to be in navigation mode, navigation information can be obtained through the navigation system, while the remaining battery power can be obtained through the battery management system.

[0059] Step S03: Determine the first target battery level corresponding to the current moment in the navigation mode based on the navigation information; the first target battery level is the battery pack's required power at the current moment when traveling from the current location to the destination, calculated based on the navigation information.

[0060] It should be noted that the first target battery level can be calculated based on navigation information, representing the battery pack's required charge at the current moment to reach the destination from the current location. For example, in pure electric mode, the battery pack will start charging when it has only 10% charge remaining. If 40% charge is needed to reach the destination from the current location, then the first target battery level at the current moment should be 50% so that the vehicle can travel to the destination without recharging in pure electric mode.

[0061] In practice, the minimum battery charge level of the battery pack can be determined based on the vehicle starting the engine to charge, and the battery charge required to travel from the current location to the destination can be determined based on navigation information. This allows us to determine the initial target battery charge level of the battery pack at the current moment.

[0062] Step S04: If the remaining battery power is less than the first target battery power, determine the engine start-up route based on the navigation information.

[0063] It should be understood that if the remaining battery power is less than the first target battery power, it means that in pure electric mode, the current remaining battery power is insufficient to support the vehicle to its destination, and the engine needs to be started to charge the battery pack.

[0064] It should be noted that the engine starting section can be a suitable section of the navigation route selected based on the average speed of traffic flow for starting the engine and charging, such as a section where the average speed of traffic flow is higher than the comfortable charging speed.

[0065] In practice, the remaining battery power is compared with the first target battery power. If the remaining battery power is greater than or equal to the first target battery power, there is no need to start the engine, and the controller maintains pure electric driving. If the remaining battery power is less than the first target battery power, the controller uses the average vehicle speed of each road segment in the navigation information to filter out road segments with an average vehicle speed greater than the comfort charging speed, and determines these road segments as engine starting road segments.

[0066] Step S05: Within the engine starting section, perform the step of acquiring wheel angular acceleration and determining the wheel-end noise of the vehicle based on the wheel angular acceleration.

[0067] It should be understood that during the engine start-up phase, the controller performs the steps of acquiring wheel angular acceleration and determining the vehicle's wheel-end noise based on this acceleration. This allows for subsequent dynamic adjustment of the engine speed limit based on ambient noise, ensuring NVH (Noise, Vibration, and Harshness) while charging. For example, a hybrid vehicle user sets navigation to a destination 100 kilometers away. Navigation information reveals the route includes three segments: city roads (average speed 30 km / h), highways (average speed 100 km / h), and rural roads (average speed 40 km / h). Upon reaching the destination, the battery level will drop by 40%, with a target of 50%. The current remaining battery level is 40%, requiring charging. Therefore, the highway segment is selected as the engine start-up phase. When the vehicle enters the highway segment, the controller acquires wheel angular acceleration and determines wheel-end noise, then dynamically sets the engine speed limit based on ambient noise, starting the engine for charging while maintaining quiet operation.

[0068] During this process, suitable high-speed road sections for starting the engine can be identified in advance when the battery is low, and a noise-based speed control strategy can be activated in such road sections to efficiently maintain battery power while ensuring NVH (noise, vibration, and harshness).

[0069] Reference Figure 4 , Figure 4 This is a schematic diagram of the second process of the third embodiment of the engine speed control method of the present invention. In this embodiment, step S04 specifically includes: Step S041: If the remaining power is less than the first target power, determine the target power generation required by the engine based on the first target power and the remaining power.

[0070] It should be understood that when hybrid vehicles plan engine startup based on navigation information, simply starting the engine on all highway sections based on a lower-than-target battery level could lead to unnecessary power generation waste or insufficient charging. For example, if the total power generation potential of the entire route far exceeds the required charge, then it is unnecessary to start the engine on all sections; power generation can be achieved on only some sections. Conversely, if the total power generation potential is insufficient, then all possible sections, including low-speed sections, need to be utilized. In this case, noise perception strategies are needed to finely control the engine speed to balance NVH (noise, vibration, and harshness) and power generation efficiency.

[0071] It should be noted that the target power generation is calculated based on the difference between the first target power and the remaining power, representing the amount of electricity that needs to be supplemented by the engine.

[0072] Step S042: Determine the first power generation of the engine at a preset speed along the entire route based on the navigation information. The preset speed is the speed at which the user will not perceive engine noise. It should be noted that the preset engine speed is a pre-calibrated, relatively low engine speed at which the engine noise is lower than the target noise level, and the user will not perceive any engine noise. For example, at 1200 rpm, the user will hardly feel the engine starting. The entire route can refer to all road segments along the navigation route from the current location to the destination. The first power generation is the total amount of electricity that the engine can charge while running at the preset engine speed throughout the entire route.

[0073] Step S043: If the first power generation is not less than the target power generation, determine the engine start-up section based on the target power generation and the preset speed; Step S044: If the first power generation is less than the target power generation, determine the entire route as the engine start-up route; Accordingly, step 05 includes: Step 051: Divide the entire route into sections with different vehicle speeds based on the navigation information; It should be noted that different speed road segments can refer to several sub-segments of the entire road segment, which are divided according to the speed limit or average traffic speed in the navigation information, such as high-speed segment, medium-speed segment, and low-speed segment, each segment having a different average speed.

[0074] Step 052: Within each divided road segment based on vehicle speed, perform the step of obtaining wheel angular acceleration and determining the wheel-end noise of the vehicle based on the wheel angular acceleration.

[0075] In practice, the target power generation required by the engine is calculated based on the difference between the initial target power level and the remaining power level. Then, the length of each sub-segment and the average vehicle speed are obtained from the navigation information. Assuming the engine operates at a preset speed, the charging power obtainable on each sub-segment is calculated. Combined with the travel time of each sub-segment, the initial power generation for the entire route is accumulated. Next, the initial power generation is compared with the target power generation. If the initial power generation is not less than the target power generation, it means that the preset speed alone is sufficient to meet the charging needs, without needing to increase the speed or utilize more road segments. In this case, based on the target power generation and the preset speed, some road segments are selected from the entire route as engine start-up segments, for example, prioritizing segments with higher vehicle speeds, so that operating at the preset speed on these segments allows for the attainment of the target power generation. If the initial power generation is less than the target power generation, it means that the preset speed alone cannot meet the charging needs, requiring the utilization of all possible road segments, and possibly requiring an increase in speed to increase power generation. In this case, the entire route is determined as the engine start-up segment. Subsequently, based on navigation information, the entire route is divided into segments with different speeds, such as high-speed, medium-speed, and low-speed segments based on average traffic speed. For example, a hybrid vehicle navigates 100 kilometers with 30% battery remaining. The initial target battery level is 50%, and the target power generation is calculated to be 20% of the battery pack's total capacity. The navigation information shows the entire route consists of three segments: a 50km high-speed segment, a 30km medium-speed segment, and a 20km low-speed segment. The preset engine speed is 1200 rpm, corresponding to a charging power of 5 kW. The calculated travel time for each segment is: 0.5 hours for the high-speed segment, 0.5 hours for the medium-speed segment, and 0.667 hours for the low-speed segment. The initial power generation is 8.335 kWh, which is less than the target power generation of 10 kWh. Therefore, the entire route is determined to be an engine-starting segment, and the entire route is divided into three speed segments. When the vehicle enters the high-speed section, the controller begins to acquire the wheel angular acceleration and determine the wheel end noise. Then, based on the ambient noise, it dynamically calculates the maximum noise speed to increase the charging power to 10 kilowatts, thereby replenishing the remaining power in the high-speed section.

[0076] In this embodiment, within each segmented vehicle speed, the maximum noise speed is dynamically calculated by combining wheel-end noise with ambient noise, thereby maximizing engine speed to increase power generation while ensuring NVH (Noise, Vibration, and Harshness).

[0077] Reference Figure 5 , Figure 5 This is a schematic diagram of the third process of the third embodiment of the engine speed control method of the present invention. In this embodiment, step S03 specifically includes: Step S031: Determine the required battery power for the vehicle to travel to its destination in the navigation mode based on the navigation information; It should be understood that when hybrid vehicles combine navigation information for battery planning, simply comparing the remaining battery level with a fixed target battery level is insufficient to accommodate the personalized needs of different users and the destination requirements of different trips. For example, users may want to retain some battery power for subsequent pure electric driving in the city upon arrival, or they may be worried about running out of battery power due to traffic congestion. If the system does not distinguish between the user-set minimum battery level for the destination, it may result in the battery being too low upon arrival, or the engine starting too early when the battery is fully charged, causing unnecessary fuel consumption.

[0078] It should be noted that the required electricity is calculated based on the driving distance, average vehicle power consumption, and fuel-electric conversion coefficient from the current location to the destination.

[0079] Step S032: Detect the minimum battery level set by the user for when the vehicle reaches its destination; It should be noted that the minimum charge level is the lowest charge level that the battery pack should retain when the vehicle reaches its destination, set by the user through the vehicle's interface. This is such as 20% SOC, and is used to ensure that there is still enough charge for pure electric driving after the vehicle arrives at its destination.

[0080] Step S033: Determine the first target battery level corresponding to the current moment in the navigation mode based on the required battery level and the minimum battery level.

[0081] In practical implementation, the system first obtains parameters such as the distance from the current location to the destination, the vehicle's average power consumption, and average fuel consumption based on navigation information. Combined with the fuel-to-electricity conversion factor, the required power consumption to reach the destination is calculated. Simultaneously, the system detects the minimum power consumption threshold entered by the user in the navigation settings interface or vehicle settings menu. Finally, the required power consumption and the minimum power consumption threshold are added together or a comprehensive calculation is performed to determine the first target power consumption at the current moment in navigation mode. For example, the first target power consumption can be the sum of the minimum power consumption threshold and the required power consumption, converted to a State of Charge (SOC) percentage. This ensures that the vehicle can meet its driving needs while retaining the user's required remaining power upon reaching the destination. For instance, a hybrid vehicle navigates to a destination 100 kilometers away. The controller calculates a required power consumption of 60% based on navigation information. The user sets a minimum power consumption threshold of 20% upon reaching the destination through the vehicle's infotainment system. Adding the required power consumption of 60% to the minimum power consumption threshold of 20% determines the first target power consumption at the current moment to be 80%. This means that during driving, the controller needs to maintain the power consumption at no less than 80% to ensure that the power consumption drops to exactly 20% upon reaching the destination, meeting the user's minimum power consumption threshold.

[0082] In this embodiment, the amount of electricity required to reach the destination can be calculated based on navigation information, and combined with the minimum guaranteed electricity level set by the user, the first target electricity level at the current moment can be determined, thereby achieving precise on-demand power supply.

[0083] Based on any one of the first to third embodiments of the engine speed control method proposed in this invention, a fourth embodiment of the engine speed control method of this invention is proposed. (Refer to...) Figure 6 , Figure 6 This is a schematic diagram of the first process of the fourth embodiment of the engine speed control method of the present invention.

[0084] In this embodiment, the engine speed control method further includes: Step S100: Detect the current operating scenario of the vehicle.

[0085] It should be understood that in hybrid vehicles, the performance of both the engine and battery will significantly degrade when the vehicle is driven in extreme environments such as high altitudes and extremely low temperatures. The engine's power decreases due to lean air intake, and the battery's discharge power is limited due to low temperatures. Both factors combined result in insufficient usable power for the entire vehicle. If a conventional NVH-priority strategy is used, the engine speed will be excessively limited, failing to provide sufficient power generation to compensate for the battery's power shortfall. This leads to a continuous decrease in battery charge, a sharp deterioration in power performance, and even safety issues such as inability to climb hills or failure to maintain battery charge.

[0086] It should be noted that the current operating scenario can be the type of external environment in which the vehicle is located, including normal scenarios and extreme scenarios. Extreme scenarios are defined by air pressure thresholds and temperature thresholds, such as high-altitude scenarios with an altitude of more than 3,000 meters or low-temperature scenarios with an ambient temperature of less than -10°C. These low-temperature scenarios will cause the battery performance to degrade, and the temperature in low-temperature scenarios can even reach -35°C.

[0087] Step S200: When the current operating scenario is an extreme scenario, obtain the environmental pressure and environmental temperature; the extreme scenarios include: high altitude scenarios and low temperature scenarios; It should be noted that ambient pressure is the real-time air pressure value of the environment in which the vehicle is located under extreme conditions, which can be collected by an atmospheric pressure sensor. Ambient temperature is the real-time air temperature value of the environment in which the vehicle is located under extreme conditions.

[0088] In practical implementation, the current operating scenario of the vehicle can be detected. For example, if the atmospheric pressure is detected by a barometric pressure sensor to be lower than a preset threshold, or the ambient temperature is detected by a temperature sensor to be lower than a preset threshold, then the current operating scenario is determined to be an extreme scenario. If the current operating scenario is detected to be an extreme scenario, the ambient pressure and ambient temperature are detected by the barometric pressure sensor and the temperature sensor.

[0089] Step S300: Determine the first maximum power of the engine and the maximum output power that the vehicle can output based on the ambient pressure and the ambient temperature; It should be noted that the first maximum power can be the engine's maximum output power under the current extreme environment. The first maximum power is calculated from the environmental pressure and temperature by fitting a polynomial model. The maximum output power is the maximum total available power that the entire vehicle system needs to ensure power performance. It is set by the vehicle model, and the maximum output power may be different for different hybrid vehicle types.

[0090] In practice, the engine's maximum power output under the current environmental conditions can be calculated using a pre-stored polynomial regression model based on environmental pressure and temperature. Simultaneously, the maximum output power required for the entire vehicle can be determined according to the vehicle model specifications.

[0091] Step S400: Determine the second maximum power required by the battery pack based on the maximum output power and the first maximum power.

[0092] It should be noted that the second maximum power is the maximum discharge power that the battery pack can provide under the current extreme environment. Since the temperature of different environments and the battery packs of different vehicle models vary, it is difficult to determine the second maximum power directly from the ambient temperature and battery pack specifications. Therefore, in this embodiment, the second maximum power can be obtained by subtracting the engine's first maximum power from the maximum output power.

[0093] Step S500: Determine the second target power required for the battery pack based on the second maximum power and the ambient temperature.

[0094] It should be noted that the second target capacity is the minimum capacity required for the battery pack to provide its second maximum power. The power output of the battery pack will vary depending on its remaining capacity; for example, the power output at a low capacity is typically lower than at a high capacity. Given the battery pack's second maximum power and the current ambient temperature, the second target capacity can be determined by consulting the battery's power-capacity table at different temperatures. In practice, based on the second maximum power and the current ambient temperature, the battery's capacity table at different temperatures and power levels can be consulted to determine the required second target capacity for the battery pack.

[0095] Step S600: If the second target power is less than the remaining power of the battery pack, determine the power supply required by the engine based on the power difference between the second target power and the remaining power. It should be noted that the power reserve is the power required by the engine to charge the battery pack to maintain the second target charge corresponding to the second maximum power output of the battery pack. In other words, it is the additional power generated by the engine that needs to be added based on the difference between the second target charge and the remaining charge.

[0096] In practice, the second target charge level can be compared with the remaining charge level of the battery pack. If the second target charge level is less than the remaining charge level, the required power output to maintain the battery's charge level is calculated based on the charge difference between the two levels, combined with a preset pull-up time.

[0097] Step S700: Determine the output power of the engine based on the power supply and the engine's base power at the maximum noise speed; It's important to note that in extreme scenarios, the engine not only needs to charge the battery pack but also provide power for vehicle operation. Base power is the power output at a base RPM calculated by the energy management module based on the vehicle's power requirements. Engine output power is the total power required by the engine in extreme scenarios, i.e., the base power plus the power reserve.

[0098] In practice, the base power of the engine at its maximum noise speed can be obtained, and the base power can be added to the power reserve to obtain the engine's output power.

[0099] Step S800: Determine the target speed of the engine based on the output power and the maximum noise speed of the engine determined based on the target noise.

[0100] It should be noted that when considering the impact of NVH, not only the engine's output power but also NVH limitations need to be taken into account. Therefore, the target speed is the speed based on the engine's output power by finding the economic line and correcting for NVH limitations under extreme scenarios.

[0101] In practice, an initial engine speed is obtained by querying the engine's economic curve based on the output power. The maximum noise speed of the engine is then determined based on the target noise level. Finally, the initial speed is compared with the maximum noise speed, and NVH limiting factors for extreme scenarios are applied to determine the engine's target speed.

[0102] Step S900: Control the engine operation based on the target speed.

[0103] It should be understood that, given a target engine speed, the engine can be controlled to operate at the target speed in extreme scenarios to prevent the vehicle from failing to function properly in extreme conditions. For example, a hybrid vehicle is traveling at an altitude of 4000 meters in a high-altitude region with an ambient temperature of -25°C. Given an extreme scenario, an ambient pressure of 60 kPa, and an ambient temperature of -25°C, a polynomial model calculates the engine's first maximum power to be 80 kW. With the vehicle's maximum output power set at 120 kW, the battery needs to provide a second maximum power of 40 kW. Consulting the battery power-temperature table, it is found that at -25°C, a 40 kW output requires 65% battery charge. With the current remaining charge at 50%, less than 65%, the charge difference is 15%. Assuming a battery capacity of 20 kWh and a recovery time of 600 seconds, the remaining charge power is 0.15. 20 3600 / 600 = 18kW. The current base power is 30kW, so the output power is 48kW. Checking the economic curve, the initial engine speed is 2800 rpm. Based on the current ambient noise, the maximum noise speed is calculated to be 2200 rpm. Therefore, the engine will be controlled at 2800 rpm to prevent the vehicle from malfunctioning. This requires sacrificing some NVH performance.

[0104] Therefore, a set of speed control logic needs to be designed specifically for extreme scenarios. By monitoring environmental pressure and temperature in real time, assessing the degree of degradation of the engine and battery, dynamically adjusting the target power and forcibly increasing the engine speed, the power retention performance and power performance are prioritized while sacrificing some NVH.

[0105] Reference Figure 7 , Figure 7 This is a schematic diagram of the second process of the fourth embodiment of the engine speed control method of the present invention. In this embodiment, step S800 further includes: Step S801: Obtain the output speed corresponding to the output power; It should be understood that in extreme scenarios, the engine needs to output higher power to maintain battery charge, and the corresponding output speed may exceed the maximum permissible speed determined by ambient noise, i.e., the maximum noise speed. If the engine is directly limited by the maximum noise speed, it will be unable to output the required power to maintain battery charge, resulting in the inability to replenish the battery and causing a continuous deterioration in power performance.

[0106] It should be noted that the output speed can be the speed value corresponding to the engine's output power under extreme conditions. The output speed corresponding to the output power can be obtained directly by looking up the engine's universal characteristic curve using the output power.

[0107] Step S802: When the output speed is greater than the maximum noise speed, determine the engine speed release coefficient under extreme conditions based on the difference between the second target charge and the remaining charge; It should be understood that when the output speed is not greater than the maximum noise speed, the engine can be controlled directly according to the output speed to ensure NVH performance and allow the vehicle to run normally. However, when the output speed is greater than the maximum noise speed, some NVH performance must be sacrificed to consider vehicle operation.

[0108] It should be noted that the speed release coefficient is a multiplier factor used to relax NVH limits. Its value is greater than or equal to 1 and is positively correlated with the difference in charge between the second target charge and the remaining charge. The larger the charge difference, the larger the coefficient.

[0109] In practice, the output speed can be compared with the maximum noise speed. If the output speed is not greater than the maximum noise speed, the output speed is directly used as the target speed. If the output speed is greater than the maximum noise speed, it indicates that the current noise limit is too strict and cannot meet the vehicle's driving requirements. In this case, the corresponding speed release coefficient can be determined by consulting a preset extreme scenario speed release coefficient table based on the difference between the second target battery level and the remaining battery level. This coefficient increases as the battery level difference increases, thus releasing NVH restrictions with greater force.

[0110] Step S803: Determine the target speed of the engine based on the maximum noise speed and the speed contact coefficient.

[0111] It should be noted that the target speed can be the final engine speed after correction by the speed removal coefficient. In practice, given the speed removal coefficient, the maximum noise speed can be directly multiplied by the speed removal coefficient to obtain the corrected target speed. The corrected target speed lies between the maximum noise speed and the output speed, thus ensuring NVH to a certain extent while also meeting the power reserve requirements. For example, in the aforementioned high-altitude and low-temperature scenario, the calculated engine output power is 48kW, and the output speed obtained from the economic curve is 2800 rpm. Meanwhile, the maximum noise speed calculated based on ambient noise and wheel-end noise is 2200 rpm. Since the output speed (2800) is greater than the maximum noise speed (2200), the corresponding speed removal coefficient of 1.27 needs to be determined by querying the difference between the second target power and the remaining power. The target speed is then approximately 2794 rpm, close to the output speed, ensuring the output of the power reserve. If the power difference is larger, for example, if the power difference between the second target power and the remaining power is 25%, the corresponding speed reduction coefficient may be 1.5, and the target speed may reach 3300 rpm, further sacrificing NVH in exchange for power retention capability.

[0112] Based on any one of the first to fourth embodiments of the engine speed control method proposed in this invention, a fifth embodiment of the engine speed control method of this invention is proposed. (Refer to...) Figure 8 , Figure 8 This is a flowchart illustrating the fifth embodiment of the engine speed control method of the present invention.

[0113] In this embodiment, the engine speed control method further includes: Step S001: Obtain the current mode, current operating scenario, and charging power required by the battery pack during pure electric operation of the vehicle; It should be understood that in hybrid vehicles, engine speed needs to meet the requirements of multiple scenarios simultaneously: NVH quietness during daily driving, power reserve requirements under navigation planning, power guarantee in extreme environments, and basic charging requirements for battery pack energy management. If the engine speed is calculated based on only a single scenario, such as limiting the engine speed only by wheel-end noise and ambient noise, the engine speed may be insufficient when power reserve is needed; if the engine speed is limited only by navigation mode, it may cause NVH deterioration on some road sections.

[0114] It should be noted that "current mode" refers to whether the vehicle's navigation is currently activated, including both non-navigation and navigation modes. "Current operating scenario" refers to the operating scenario corresponding to the vehicle's current external environment, including normal and extreme scenarios. "Charging capacity" is the calculated amount of electricity the battery pack needs to replenish during pure electric operation.

[0115] In practice, the vehicle's current mode can be determined by detecting whether the vehicle navigation system is turned on and whether the vehicle is in navigation mode; the current operating scenario can be determined based on the ambient temperature and pressure outside the vehicle, as well as the charging power required by the battery pack during pure electric operation.

[0116] Step S002: Obtain the required navigation speed of the engine when the current mode is navigation mode, the extreme speed when the current scenario is an extreme scenario, and the charging speed corresponding to the charging capacity; It should be noted that the navigation RPM is the engine speed used for battery charging, calculated based on navigation information and the battery level difference in navigation mode. The extreme RPM is the engine speed used for battery charging under extreme conditions, calculated based on ambient pressure and temperature. The charging RPM can be a base RPM calculated based on whether the battery pack needs charging.

[0117] In practice, the maximum noise speed can be determined first based on the target noise; the required navigation speed in navigation mode can be calculated using navigation information in navigation mode and the remaining power of the battery pack; the extreme speed of the engine in extreme mode can be determined based on parameters such as environmental pressure, ambient temperature, maximum output power of the vehicle, and the first target power required by the battery pack in extreme scenarios; and the charging speed at which the engine needs to charge the battery pack can be determined based on the charging power required by the battery pack in pure electric mode.

[0118] In pure electric operation, the charging speed corresponding to the charging capacity can be determined by considering the minimum baseline charging capacity required for the battery pack and its current remaining capacity. This, along with the required output power and the current output power of the battery pack, determines the necessary charging speed. If the user has set a minimum charge level, the battery pack's continuous discharge capacity can be determined based on this minimum charge level and its current remaining capacity. Then, the required charging capacity for the battery pack is determined based on the energy needed for vehicle operation, and finally, the required charging speed for the engine is determined based on this charging capacity.

[0119] Step S003: The current mode of the vehicle, the current operating scenario, and the charging power required by the battery pack during vehicle operation determine the speed ratios corresponding to the maximum noise speed, the navigation speed, the charging speed, and the extreme speed, respectively. It should be noted that the speed ratio is a weighting coefficient of the speed under different conditions in the final arbitration, and the sum of these coefficients is 1. The ratio is dynamically allocated based on wheel-end noise and ambient noise, current mode, scenario, and whether the battery pack needs to be charged. For example, the extreme speed ratio is the largest in extreme scenarios, and the navigation speed ratio increases in navigation mode.

[0120] In practice, based on the vehicle's current mode, current operating scenario, and charging capacity, the percentage of speed corresponding to the maximum noise speed, navigation speed, charging speed, and extreme speed is determined by querying a preset dynamic weight allocation table. For example, if the current scenario is extreme, the extreme speed percentage is the largest, say 'a', and the charging speed percentage required for the battery pack in pure electric mode is (1-a), while the percentages of speed corresponding to the maximum noise speed and navigation speed are both zero. If it is not an extreme scenario and navigation mode is triggered, the speed percentage 'b' of navigation speed is determined based on the battery level difference and distance completion, the speed percentage 'c' is determined based on the throttle and vehicle speed during pure electric operation, and the speed percentage corresponding to the maximum noise speed for environmental noise and wheel-end noise is (1-bc). If no special scenario is triggered, the speed percentage 'c' is determined based on the throttle and vehicle speed during pure electric operation, and the speed percentage corresponding to the maximum noise speed for environmental noise and wheel-end noise is (1-c).

[0121] Step S004: Based on the speed ratio, the maximum noise speed, the navigation speed, the charging speed, and the extreme speed are weighted to obtain the vehicle's final speed.

[0122] It should be noted that the final RPM is determined by comprehensively considering various influencing factors such as target noise perceived by the user, whether the vehicle is in navigation mode, whether the battery pack needs charging, and whether the vehicle is in extreme scenarios.

[0123] In practical implementation, given the specific speed values ​​and corresponding percentages of each speed, a weighted sum can be performed on each speed and its percentage to determine the vehicle's final speed. The engine operation is then controlled based on this final speed. For example, a hybrid vehicle is currently in a non-extreme scenario, with navigation off, a speed of 60 km / h, and a throttle opening of 30%. In pure electric mode, the percentage of the speed corresponding to the charging speed is 0.6, and the percentage of the speed corresponding to the maximum noise speed is 0.4. Calculating the charging speed to be 1800 rpm and the maximum noise speed to be 2200 rpm, the final speed = 0.6. 1800 0.4 2200 = 1960 RPM. For example, if the vehicle is currently in navigation mode and the difference between the target battery level and the remaining battery level is large, the navigation RPM percentage can be set to 0.5, the charging RPM percentage to 0.3, and the maximum noise RPM percentage to 0.2. With a navigation RPM of 2500 RPM, a charging RPM of 1800 RPM, and a maximum noise RPM of 2100 RPM, the final RPM = 0.3. 1800+0.2 2100 + 0.5 2500 = 2210 revolutions per minute.

[0124] In this embodiment, by detecting factors in multiple modes, the percentage of each speed is dynamically allocated based on factors such as whether the vehicle is in navigation mode, whether it is in an extreme scenario, and the degree of battery depletion. The final speed is obtained by weighted averaging, thereby achieving the comprehensive optimization of NVH, economy, and power.

[0125] It should be noted that the above examples are only for understanding the present invention and do not constitute a limitation on the engine speed control method of the present invention. Any simple modifications based on this technical concept are within the protection scope of the present invention.

[0126] In addition, refer to Figure 9 , Figure 9This is a schematic diagram of the engine speed control device proposed in this invention. To achieve the above objectives, this invention also provides an engine speed control device, comprising: The noise determination module 10 is used to acquire the wheel angular acceleration and determine the wheel end noise of the vehicle based on the wheel angular acceleration. The noise determination module 10 is also used to detect ambient noise in the cockpit; The noise determination module 10 is also used to determine the target noise that the user can perceive based on the wheel end noise and the ambient noise; The speed determination module 20 is used to determine the maximum noise speed of the engine based on the target noise. The speed determination module 20 is also used to control the engine to start based on the maximum noise speed when the vehicle engine needs to be started.

[0127] In this embodiment, the engine speed control device includes a noise determination module 10, used to acquire wheel angular acceleration and determine the wheel-end noise of the vehicle based on the wheel angular acceleration; the noise determination module 10 is also used to detect ambient noise in the cockpit; the noise determination module 10 is also used to determine the target noise that the user can perceive based on the wheel-end noise and the ambient noise; the speed determination module 20 is used to determine the maximum noise speed of the engine based on the target noise; the speed determination module 20 is also used to control the engine to start based on the maximum noise speed when the vehicle engine needs to be started. This device determines the target noise that the user can perceive by detecting the wheel-end noise and the ambient noise in the cockpit, and then determines the corresponding maximum noise speed of the engine. During actual vehicle operation, the engine speed can be controlled based on the noise that the user can perceive, making full use of the noise masking effect to improve power generation or power retention, thereby avoiding losses in economy and power.

[0128] Furthermore, in this embodiment, the noise determination module 10 is also used to acquire a first noise frequency of the engine noise, a second noise frequency of the wheel end noise, and a third noise frequency of the ambient noise; determine the weights corresponding to the wheel end noise and the ambient noise respectively based on the first noise frequency, the second noise frequency, and the third noise frequency; and perform a weighted summation of the wheel end noise, the ambient noise, the weights corresponding to the wheel end noise, and the weights corresponding to the ambient noise to determine the target noise that the user can perceive.

[0129] Furthermore, in this embodiment, the engine speed control device further includes: a mode detection module, used to detect whether the current mode of the vehicle is in navigation mode; a power calculation module, used to obtain navigation information of the navigation mode and the remaining power of the battery pack in the vehicle if so; the power calculation module is also used to determine a first target power corresponding to the current time in the navigation mode based on the navigation information; the power calculation module is also used to determine the engine start-up section based on the navigation information when the remaining power is less than the first target power; the noise determination module 10 is also used to perform the step of obtaining wheel angular acceleration and determining the wheel end noise of the vehicle based on the wheel angular acceleration within the engine start-up section.

[0130] Furthermore, in this embodiment, the power calculation module is also used to determine the target power generation required by the engine based on the first target power generation and the remaining power generation when the remaining power generation is less than the first target power generation; determine the first power generation of the engine at a preset speed on the entire road segment according to the navigation information, the preset speed being a speed at which the user will not perceive engine noise; determine the engine starting segment based on the target power generation and the preset speed when the first power generation is not less than the target power generation; determine the entire road segment as the engine starting segment when the first power generation is less than the target power generation; the noise determination module 10 is also used to divide the entire road segment into different speed segments according to the navigation information; and perform the step of obtaining wheel angular acceleration and determining the wheel end noise of the vehicle based on the wheel angular acceleration within each divided speed segment.

[0131] Furthermore, in this embodiment, the power calculation module is also used to determine the power required for the vehicle to travel to its destination in the navigation mode based on the navigation information; detect the minimum power requirement set by the user for the vehicle to reach its destination; and determine the first target power requirement corresponding to the current moment in the navigation mode based on the power requirement and the minimum power requirement.

[0132] Furthermore, in this embodiment, the mode detection module is used to detect the current operating scenario of the vehicle; the power determination module is used to acquire the ambient pressure and ambient temperature when the current operating scenario is an extreme scenario; the power determination module is also used to determine the first maximum power corresponding to the engine and the maximum output power that the vehicle can output based on the ambient pressure and the ambient temperature; the power determination module is also used to determine the second maximum power required by the battery pack based on the maximum output power and the first maximum power; the power calculation module is also used to determine the second target power required by the battery pack based on the second maximum power and the ambient temperature; the power determination module is also used to determine the power reserve power required by the engine based on the power difference between the second target power and the remaining power when the second target power is less than the remaining power of the battery pack; the output power of the engine is determined based on the power reserve power and the base power of the engine at the maximum noise speed; the speed determination module 20 is also used to determine the target speed of the engine based on the output power and the maximum noise speed of the engine based on the target noise; and control the engine operation based on the target speed.

[0133] Furthermore, in this embodiment, the speed determination module 20 is also used to obtain the output speed corresponding to the output power; when the output speed is greater than the maximum noise speed, determine the speed release coefficient of the engine under extreme conditions based on the difference between the second target charge and the remaining charge; and obtain the current mode of the vehicle, the current operating scenario, and the charging charge required by the battery pack during the pure electric operation of the vehicle. Furthermore, in this embodiment, the speed determination module 20 is also used to obtain the navigation speed required by the engine when the current mode is navigation mode, the extreme speed when the current scenario is extreme scenario, and the charging speed corresponding to the charging power. The current mode of the vehicle, the current operating scenario, and the charging power required by the battery pack during vehicle operation determine the speed ratios corresponding to the maximum noise speed, the navigation speed, the charging speed, and the extreme speed, respectively. Based on the speed ratios, the maximum noise speed, the navigation speed, the charging speed, and the extreme speed are weighted to obtain the final speed of the vehicle. The target speed of the engine is determined based on the maximum noise speed and the speed contact coefficient.

[0134] The engine speed control device can execute the engine speed control method described in any of the above embodiments. The control logic between the controller and various devices can be referred to the embodiments of the above engine speed control method, which will not be elaborated here.

[0135] In addition, to achieve the above objectives, the present invention also provides a vehicle, the vehicle including a controller, an engine and a battery pack; the controller is used to execute the engine speed control method described in any of the above embodiments.

[0136] The controller is used to execute the engine speed control method described in any of the above embodiments. The control logic between the controller and the various devices can be referred to the embodiments of the engine speed control method described above, and will not be repeated here.

[0137] The above description is only a part of the embodiments of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the technical concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An engine speed control method, characterized in that, The engine speed control method, applied to hybrid vehicles, includes: The wheel angular acceleration is obtained, and the wheel-end noise of the vehicle is determined based on the wheel angular acceleration; Detect ambient noise inside the cockpit; The target noise that the user can perceive is determined based on the wheel end noise and the ambient noise. The maximum noise speed of the engine is determined based on the target noise. When it is necessary to start the vehicle engine, the engine is started based on the maximum noise speed.

2. The engine speed control method as described in claim 1, characterized in that, The step of determining the target noise that the user can perceive based on the wheel end noise and the ambient noise includes: The first noise frequency of the engine noise, the second noise frequency of the wheel end noise, and the third noise frequency of the ambient noise are obtained. The weights corresponding to the wheel end noise and the ambient noise are determined based on the first noise frequency, the second noise frequency, and the third noise frequency. The target noise that the user can perceive is determined by weighted summation of the wheel end noise, the ambient noise, the weight corresponding to the wheel end noise, and the weight corresponding to the ambient noise.

3. The engine speed control method as described in claim 1, characterized in that, The engine speed control method further includes: Detect whether the vehicle's current mode is navigation mode, the current mode including navigation mode and non-navigation mode; If so, then obtain the navigation information of the navigation mode and the remaining power of the battery pack in the vehicle; The first target battery level corresponding to the current moment in the navigation mode is determined based on the navigation information; the first target battery level is the battery pack's required power at the current moment when traveling from the current location to the destination, calculated based on the navigation information. If the remaining battery power is less than the first target battery power, the engine start-up route is determined based on the navigation information; Within the engine starting section, the steps of acquiring wheel angular acceleration and determining the vehicle's wheel-end noise based on the wheel angular acceleration are performed.

4. The engine speed control method as described in claim 3, characterized in that, The step of determining the engine start-up route based on the navigation information when the remaining battery power is less than the first target battery power includes: If the remaining power is less than the first target power, the target power generation required by the engine is determined based on the first target power and the remaining power. Based on the navigation information, the engine generates a first amount of electricity at a preset speed throughout the entire route. The preset speed is a speed at which the user will not perceive engine noise. If the first power generation is not less than the target power generation, the engine start-up route is determined based on the target power generation and the preset speed. If the first power generation is less than the target power generation, the entire route is determined to be an engine start-up route. Accordingly, the step of acquiring wheel angular acceleration and determining the vehicle's wheel-end noise based on the wheel angular acceleration during the engine start-up section includes: The entire route is divided into sections with different vehicle speeds based on the navigation information. Within each segment of the road with different vehicle speeds, the steps of obtaining wheel angular acceleration and determining the wheel-end noise of the vehicle based on the wheel angular acceleration are performed.

5. The engine speed control method as described in claim 3, characterized in that, Determining the first target battery level corresponding to the current moment in the navigation mode based on the navigation information includes: The required battery power for the vehicle to travel to its destination in the navigation mode is determined based on the navigation information. Detects the minimum battery level set by the user when the vehicle reaches its destination; The first target battery level corresponding to the current moment in the navigation mode is determined based on the required battery level and the minimum required battery level.

6. The engine speed control method as described in claim 1, characterized in that, The engine speed control method further includes: Detect the current operating scenario of the vehicle; Under the condition that the current operating scenario is an extreme scenario, the environmental pressure and environmental temperature are obtained; the extreme scenarios include: high-altitude scenarios and low-temperature scenarios. The first maximum power of the engine and the maximum output power that the vehicle can output are determined based on the ambient pressure and the ambient temperature. The second maximum power required by the battery pack is determined based on the maximum output power and the first maximum power. The second target power required for the battery pack is determined based on the second maximum power and the ambient temperature. If the second target charge is less than the remaining charge of the battery pack, the required power output of the engine is determined based on the charge difference between the second target charge and the remaining charge. The output power of the engine is determined based on the power reserve and the engine's base power at the maximum noise speed. The target speed of the engine is determined based on the output power and the maximum noise speed of the engine. The engine is controlled to operate based on the target speed.

7. The engine speed control method as described in claim 6, characterized in that, The method of determining the target engine speed based on the output power and the maximum noise speed of the engine based on the target noise further includes: Obtain the output speed corresponding to the output power; When the output speed is greater than the maximum noise speed, the speed release coefficient of the engine under extreme conditions is determined based on the difference between the second target charge and the remaining charge. The target speed of the engine is determined based on the maximum noise speed and the speed contact coefficient.

8. The engine speed control method according to any one of claims 1 to 7, characterized in that, The engine speed control method further includes: The current mode, current operating scenario, and charging power required by the battery pack during pure electric operation of the vehicle are obtained. Obtain the engine's required navigation speed when the current mode is navigation mode, the extreme speed under the current scenario, and the charging speed corresponding to the charging capacity; The current mode of the vehicle, the current operating scenario, and the charging power required by the battery pack during vehicle operation determine the speed percentages corresponding to the maximum noise speed, the navigation speed, the charging speed, and the extreme speed, respectively. The vehicle's final speed is obtained by weighting the maximum noise speed, the navigation speed, the charging speed, and the extreme speed based on the speed ratio.

9. An engine speed control device, characterized in that, include: A noise determination module is used to acquire wheel angular acceleration and determine the wheel-end noise of the vehicle based on the wheel angular acceleration. The noise determination module is also used to detect ambient noise in the cockpit; The noise determination module is also used to determine the target noise that the user can perceive based on the wheel end noise and the ambient noise; A speed determination module is used to determine the maximum noise speed of the engine based on the target noise. The speed determination module is also used to control the engine to start based on the maximum noise speed when the vehicle engine needs to be started.

10. A vehicle, characterized in that, The vehicle includes: a controller, an engine, and a battery pack; The controller is used to execute the engine speed control method according to any one of claims 1 to 8.

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