Vehicle engine direct drive speed ratio determination method and device, equipment and storage medium

Abstract

The invention provides a vehicle engine direct-drive speed ratio determination method, device and equipment and a storage medium. The method comprises the steps that an initial direct-drive speed ratio range and multiple direct-drive vehicle speeds are obtained, the initial direct-drive speed ratio range is determined based on an engine preset power demand, and the multiple direct-drive vehicle speeds are determined based on a vehicle speed range in an engine direct-drive mode; based on the direct-drive speed ratio range and the multiple direct-drive vehicle speeds, fuel consumption simulation testing is conducted on the vehicle, and a target direct-drive speed ratio is obtained according to a fuel consumption simulation testing result; engine excitation frequencies of the engine at the multiple direct-drive vehicle speeds are calculated according to the target direct-drive speed ratio; comparing the engine excitation frequency with excitation frequencies of a plurality of vehicle parts in a pre-stored whole vehicle modal frequency avoiding table, and if a comparison result meets a preset frequency avoiding condition, taking the target direct-drive speed ratio as a direct-drive speed ratio determination result, by means of the method, the technical problem that in the related technology, fuel economy and comfort are poor in the engine direct drive mode is solved.

Description

Technical Field

[0001] This application relates to the technical field of vehicle engines, and particularly to a method, device, equipment and storage medium for determining the direct drive speed ratio of a vehicle engine. Background Art

[0002] In recent years, the rapid development of the new energy vehicle industry has promoted the emergence of various new power systems. Among them, hybrid electric vehicles (HEVs), as a transitional solution between traditional fuel vehicles and pure electric vehicles, rely on their unique dual power source design - that is, combining internal combustion engines (including diesel engines and gasoline engines) with electric motors, and flexibly switching or working in coordination according to the actual driving state of the vehicle, providing efficient and flexible power output. This characteristic has enabled hybrid electric vehicles to gain wide recognition in the market. In particular, the direct drive mode of the engine, because it can directly utilize the high-efficiency operating range of the internal combustion engine to drive the vehicle, has become one of the key technologies in the hybrid power system.

[0003] However, in the direct drive mode of the engine, the speed ratio matching becomes a key factor affecting the comprehensive performance of the vehicle. The selection of the speed ratio not only determines the efficiency of power transmission, but also deeply affects the power performance, fuel economy and NVH (noise, vibration and harshness) performance of the vehicle. The design of the direct drive speed ratio in the related art mainly focuses on improving the power performance of the vehicle, ensuring that sufficient torque and power can be quickly responded and output when needed, thus ignoring the fuel economy and NVH (noise, vibration and harshness) performance, resulting in poor fuel economy and comfort in the direct drive mode of the related art. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the related art, this application provides a method, device, equipment and storage medium for determining the direct drive speed ratio of a vehicle engine to solve the technical problems of poor fuel economy and comfort in the direct drive mode of the related art.

[0005] This application provides a method for determining the direct drive speed ratio of a vehicle engine, and the method for determining the direct drive speed ratio of the vehicle engine includes:

[0006] In an embodiment of the present application, an initial direct drive speed ratio range and multiple direct drive vehicle speeds are obtained. The initial direct drive speed ratio range is determined based on a preset power demand of the engine, and the multiple direct drive vehicle speeds are determined based on a vehicle speed range in the engine direct drive mode. A fuel consumption simulation test of the vehicle is performed based on the initial direct drive speed ratio range and the multiple direct drive vehicle speeds, and a target direct drive speed ratio is obtained according to the result of the fuel consumption simulation test. The engine excitation frequency of the engine at the multiple direct drive vehicle speeds is calculated according to the target direct drive speed ratio. The engine excitation frequency is compared with the excitation frequencies of multiple vehicle components in a pre-stored vehicle mode frequency avoidance table. If the comparison result meets a preset frequency avoidance condition, the target direct drive speed ratio is used as the direct drive speed ratio determination result.

[0007] In an embodiment of the present application, performing a fuel consumption simulation test of the vehicle based on the initial direct drive speed ratio range and the multiple direct drive vehicle speeds, and obtaining a target direct drive speed ratio according to the result of the fuel consumption simulation test includes: obtaining the vehicle speed statistical frequency of each direct drive vehicle speed, and assigning weights to each direct drive vehicle speed based on the vehicle speed statistical frequency; obtaining multiple initial direct drive speed ratios based on the initial direct drive speed ratio range, performing a fuel consumption simulation test on each initial direct drive speed ratio, and obtaining the fuel consumption per 100 kilometers corresponding to each direct drive vehicle speed at each initial direct drive speed ratio; obtaining the comprehensive fuel consumption corresponding to each initial direct drive speed ratio according to the fuel consumption per 100 kilometers corresponding to each direct drive vehicle speed at each initial direct drive speed ratio and the weight corresponding to each direct drive vehicle speed; and using the initial direct drive speed ratio with the lowest comprehensive fuel consumption as the target direct drive speed ratio.

[0008] In an embodiment of the present application, calculating the engine excitation frequency of the engine at the multiple direct drive vehicle speeds according to the target direct drive speed ratio includes: obtaining the wheel radius of the vehicle, and obtaining the engine speed at each direct drive vehicle speed according to the wheel radius, the target direct drive speed ratio, and the multiple direct drive vehicle speeds; and obtaining the engine excitation frequencies of multiple firing orders at each direct drive vehicle speed based on the engine speed at each direct drive vehicle speed and a preset firing order.

[0009] In one embodiment of the present application, after comparing the engine excitation frequency with the excitation frequencies of multiple vehicle components in a pre-stored vehicle modal frequency avoidance table, the following steps are further included: If the comparison result shows that the difference between the excitation frequency of one or more vehicle components in the vehicle modal frequency avoidance table and the engine excitation frequency is less than a preset difference threshold, then the one or more vehicle components are regarded as components to be optimized. The preset frequency avoidance condition includes that the comparison result shows that the differences between the excitation frequencies of the multiple vehicle components in the vehicle modal frequency avoidance table and the engine excitation frequency are all greater than or equal to the preset difference threshold. After replacing or adjusting the components to be optimized, the vehicle modal frequency avoidance table is updated, and a re-comparison is performed based on the updated vehicle modal frequency avoidance table and the engine excitation frequency to make the re-comparison result meet the preset frequency avoidance condition.

[0010] In one embodiment of the present application, after regarding the one or more vehicle components as components to be optimized, the following steps are further included: If the components to be optimized cannot be replaced or adjusted, then a secondary direct drive speed ratio is obtained according to the result of the fuel consumption simulation test, and the secondary direct drive speed ratio is used as the new target direct drive speed ratio. The engine excitation frequency at the new target direct drive speed ratio is obtained according to the new target direct drive speed ratio, and the engine excitation frequency at the new target direct drive speed ratio is re-compared with the excitation frequencies of multiple vehicle components in the vehicle modal frequency avoidance table. If the re-comparison result meets the preset frequency avoidance condition, then the new target direct drive speed ratio is used as the direct drive speed ratio determination result.

[0011] In one embodiment of the present application, comparing the engine excitation frequency with the excitation frequencies of multiple vehicle components in a pre-stored vehicle modal frequency avoidance table includes: If the engine is a four-cylinder four-stroke engine, then the second-order engine excitation frequency and the fourth-order engine excitation frequency are compared with the excitation frequencies of vehicle components in the vehicle modal frequency avoidance table. The multiple firing orders at least include the first order, the second order, the third order, and the fourth order.

[0012] In one embodiment of the present application, after obtaining the initial direct drive speed ratio range and multiple direct drive vehicle speeds, the following steps are further included: Obtain the wheel radius of the vehicle, and obtain the highest engine speed and the lowest engine speed according to the wheel radius, the target direct drive speed ratio, and the multiple direct drive vehicle speeds. Perform a bench test on the engine to obtain the universal characteristic curve of the engine, and determine the economic torque range of the engine based on the universal characteristic curve. Obtain the economic highest speed and the economic lowest speed according to the economic torque range of the engine. If the highest engine speed is greater than the economic highest speed or the lowest engine speed is less than the economic lowest speed, then the initial direct drive speed ratio range is adjusted so that the highest engine speed is less than or equal to the economic highest speed and the lowest engine speed is greater than or equal to the economic lowest speed.

[0013] An embodiment of the present application further provides a device for determining the direct drive speed ratio of a vehicle engine. The device for determining the direct drive speed ratio of a vehicle engine includes: an information input module, configured to obtain an initial direct drive speed ratio range and a plurality of direct drive vehicle speeds. The initial direct drive speed ratio range is determined based on the preset power demand of the engine, and the plurality of direct drive vehicle speeds are determined based on the vehicle speed range in the engine direct drive mode; a fuel consumption simulation module, configured to perform a fuel consumption simulation test on the vehicle based on the initial direct drive speed ratio range and the plurality of direct drive vehicle speeds, and obtain a target direct drive speed ratio according to the result of the fuel consumption simulation test; a frequency calculation module, configured to calculate the engine excitation frequency of the engine at the plurality of direct drive vehicle speeds according to the target direct drive speed ratio; a frequency comparison module, configured to compare the engine excitation frequency with the excitation frequencies of a plurality of vehicle components in a pre-stored vehicle modal frequency avoidance table. If the comparison result meets the preset frequency avoidance condition, the target direct drive speed ratio is used as the direct drive speed ratio determination result.

[0014] An embodiment of the present application further provides an electronic device. The electronic device includes: one or more processors; a storage device, configured to store one or more programs. When the one or more programs are executed by the one or more processors, the electronic device implements the method for determining the direct drive speed ratio of a vehicle engine as described in any one of the above embodiments.

[0015] An embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor of a computer, the computer is caused to execute the method for determining the direct drive speed ratio of a vehicle engine as described in any one of the above embodiments.

[0016] Advantages of the present application: An embodiment of the present application provides a method, device, equipment and storage medium for determining the direct drive speed ratio of a vehicle engine. The method obtains an initial direct drive speed ratio range and a plurality of direct drive vehicle speeds. The initial direct drive speed ratio range is determined based on the preset power demand of the engine, and the plurality of direct drive vehicle speeds are determined based on the vehicle speed range in the engine direct drive mode; performs a fuel consumption simulation test on the vehicle based on the direct drive speed ratio range and the plurality of direct drive vehicle speeds, and obtains a target direct drive speed ratio according to the result of the fuel consumption simulation test; calculates the engine excitation frequency of the engine at the plurality of direct drive vehicle speeds according to the target direct drive speed ratio; compares the engine excitation frequency with the excitation frequencies of a plurality of vehicle components in a pre-stored vehicle modal frequency avoidance table. If the comparison result meets the preset frequency avoidance condition, the target direct drive speed ratio is used as the direct drive speed ratio determination result. By performing a fuel consumption simulation test on the engine, the fuel economy in the engine direct drive mode is optimized on the premise of meeting the vehicle power performance. By optimizing the frequency avoidance of vehicle components, the NVH resonance risk in the engine direct drive mode is avoided, thereby improving the fuel economy and comfort in the engine direct drive mode.

[0017] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and do not limit this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of a simplified hybrid assembly model of a vehicle engine direct drive ratio determination method shown in an exemplary embodiment of this application;

[0019] Figure 2 is a flowchart of a vehicle engine direct drive ratio determination method shown in an exemplary embodiment of this application;

[0020] Figure 3 is a schematic diagram of a direct drive ratio optimization process shown in an exemplary embodiment of this application;

[0021] Figure 4 is a block diagram of a vehicle engine direct drive ratio determination device shown in an exemplary embodiment of this application;

[0022] Figure 5 is a schematic diagram of a structure of an electronic device shown in an exemplary embodiment of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following uses specific specific examples to illustrate the embodiments of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0024] It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of this application in a schematic manner. Therefore, only the components related to this application are shown in the drawings, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0025] It should be noted that in this application, "first", "second", etc. are only used to distinguish similar objects, and are not used to limit the order or sequence of similar objects. The described "including", "having", etc. are deformed, indicating that the scope covered by the subject of this word is not exclusive except for the examples shown by this word.

[0026] It is understood that the various numerical numbers, step numbers, etc. recorded in this application are for the convenience of description and do not limit the scope of this application. The size of the labels in this application does not imply the order of execution. The execution order of each process should be determined by its function and internal logic.

[0027] In the following description, a large number of details are explored to provide a more thorough explanation of the embodiments of this application. However, it is obvious to those skilled in the art that the embodiments of this application can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of this application difficult to understand.

[0028] Embodiments of this application respectively propose a method for determining the direct drive speed ratio of a vehicle engine, a device for determining the direct drive speed ratio of a vehicle engine, an electronic device, a computer-readable storage medium, and a computer program product. These embodiments will be described in detail below.

[0029] Please refer to Figure 1 , Figure 1 which is a schematic diagram of a simplified hybrid powertrain model of a method for determining the direct drive speed ratio of a vehicle engine shown in an exemplary embodiment of this application.

[0030] The power system structure of a hybrid vehicle mainly consists of components such as an engine, a clutch, a generator, a drive motor, a power battery, and a main reduction differential. It can achieve various modes such as pure electric drive mode, engine direct drive mode, series mode, parallel mode, and energy recovery according to needs and controller commands. Among them, in the engine direct drive mode, the engine torque is directly transmitted to the main reducer and differential through the engine gear set and the intermediate shaft, and then transmitted to the wheels. It is mainly applied to the medium and high-speed constant-speed cruising conditions of the vehicle and is widely used in vehicle usage scenarios such as urban expressways and highways. The simplified hybrid powertrain model is as Figure 1 shown, which is mainly used to calculate the engine direct drive speed ratio i. In Figure 1 , Z1 is the number of teeth of the engine direct drive gear, Z2 is the number of teeth of the intermediate shaft input gear, Z3 is the number of teeth of the intermediate shaft output gear, Z4 is the number of teeth of the main reducer gear, Z5 is the number of teeth of the drive motor gear, and Z6 is the number of teeth of the generator gear. The calculation formula for the engine direct drive speed ratio i is as follows:

[0031]

[0032] In Equation (1), Z3 is the number of teeth of the intermediate shaft output gear, Z1 is the number of teeth of the engine direct drive gear, Z3 is the number of teeth of the intermediate shaft output gear, and Z4 is the number of teeth of the main reducer gear. According to Equation (1), if the target direct drive speed ratio is 3.2, then Z1 is 96, Z2 is 83, Z3 is 23, and Z4 is 85.

[0033] Please refer to Figure 2 , Figure 2 which is a flowchart of a method for determining the direct drive speed ratio of a vehicle engine shown in an exemplary embodiment of the present application. As Figure 2 shown, in an exemplary embodiment, the method for determining the direct drive speed ratio of a vehicle engine at least includes steps S210 to S240, which are introduced in detail as follows:

[0034] Step S210: Obtain the initial direct drive speed ratio range and multiple direct drive vehicle speeds. The initial direct drive speed ratio range is determined based on the preset power requirement of the engine, and the multiple direct drive vehicle speeds are determined based on the vehicle speed range in the engine direct drive mode.

[0035] In an embodiment of the present application, after obtaining the initial direct drive speed ratio range and multiple direct drive vehicle speeds, it further includes: obtaining the wheel radius of the vehicle, and obtaining the maximum engine speed and the minimum engine speed according to the wheel radius, the target direct drive speed ratio and the multiple direct drive vehicle speeds; conducting a bench test on the engine to obtain the universal characteristic curve of the engine, and determining the economic torque range of the engine based on the universal characteristic curve; obtaining the economic maximum speed and the economic minimum speed according to the economic torque range of the engine; if the maximum engine speed is greater than the economic maximum speed or the minimum engine speed is less than the economic minimum speed, then adjust the initial direct drive speed ratio range so that the maximum engine speed is less than or equal to the economic maximum speed and the minimum engine speed is greater than or equal to the economic minimum speed.

[0036] In an embodiment of the present application, the wheel radius is calculated according to the vehicle tire model. In this embodiment, the tire model is 255 / 50R20, and the wheel radius is calculated to be 0.3815 m according to the following formula.

[0037]

[0038] In formula (2), r represents the wheel radius, A represents the tire width, B represents the flat rate, and C represents the wheel hub diameter, where the tire width, flat rate and wheel hub diameter can all be obtained according to the tire model.

[0039] In an embodiment of the present application, a single-cylinder bench test is conducted on the engine to obtain the corresponding universal characteristic curve of the engine. The abscissa of the universal characteristic curve is the engine speed, and the ordinate is the engine torque. The economic torque range of the engine and the economic maximum speed and economic minimum speed corresponding to the economic torque range can be determined from the universal characteristic curve. In order to make the direct drive speed ratios in the initial direct drive speed ratio range satisfy torque economy, it is necessary to ensure that the maximum engine speed at each direct drive speed under the initial direct drive speed ratio range is less than or equal to the economic maximum speed and the minimum engine speed is greater than or equal to the economic minimum speed.

[0040] In one embodiment of the present application, the initial direct drive speed ratio range is determined based on the preset power demand of the engine, which includes the maximum vehicle speed, acceleration performance, climbing performance, etc. The demand power of the engine is obtained according to the preset power demand of the engine, and the initial direct drive speed ratio range is calculated based on the demand power. The initial direct drive speed ratio range is used to ensure that the finally determined target direct drive speed ratio can meet the power performance requirements of the whole vehicle. In this embodiment, the initial direct drive speed ratio range can be 2.25 - 4.32.

[0041] In one embodiment of the present application, according to the engine characteristics, the vehicle control strategy and the working mode, the constant speed cruise vehicle speed range (vehicle speed range) in the engine direct drive mode is determined, and multiple direct drive vehicle speeds are obtained based on the constant speed cruise vehicle speed range. In this embodiment, the constant speed cruise vehicle speed range is 60 - 140 km / h, and the multiple direct drive vehicle speeds are 60 km / h, 70 km / h, 80 km / h, 90 km / h, 100 km / h, 110 km / h, 120 km / h, 130 km / h and 140 km / h.

[0042] Step S220: Conduct a fuel consumption simulation test on the vehicle based on the initial direct drive speed ratio range and the multiple direct drive vehicle speeds, and obtain the target direct drive speed ratio according to the results of the fuel consumption simulation test.

[0043] In one embodiment of the present application, conducting a fuel consumption simulation test on the vehicle based on the initial direct drive speed ratio range and the multiple direct drive vehicle speeds, and obtaining the target direct drive speed ratio according to the results of the fuel consumption simulation test includes: obtaining the vehicle speed statistical frequency of each direct drive vehicle speed, and assigning weights to each direct drive vehicle speed based on the vehicle speed statistical frequency; obtaining multiple initial direct drive speed ratios based on the initial direct drive speed ratio range, conducting a fuel consumption simulation test on each initial direct drive speed ratio, and obtaining the fuel consumption per 100 kilometers corresponding to each direct drive vehicle speed under each initial direct drive speed ratio; obtaining the comprehensive fuel consumption corresponding to each initial direct drive speed ratio according to the fuel consumption per 100 kilometers corresponding to each direct drive vehicle speed under each initial direct drive speed ratio and the weights corresponding to each direct drive vehicle speed; and taking the initial direct drive speed ratio with the lowest comprehensive fuel consumption as the target direct drive speed ratio.

[0044] In one embodiment of the present application, the vehicle speed statistical frequency of each direct drive vehicle speed is obtained based on the actual working conditions of the whole vehicle, and weight assignment is carried out on each direct drive vehicle speed according to the vehicle speed statistical frequency, so as to obtain the comprehensive fuel consumption under each initial direct drive speed ratio based on weighted summation, and thus select the target direct drive speed ratio based on the comprehensive fuel consumption to obtain the engine direct drive speed ratio that meets the fuel consumption economy.

[0045] As shown in Table 1, Table 1 is the result of the fuel consumption simulation test at a certain initial direct drive speed ratio:

[0046] Table 1

[0047]

[0048] In Table 1, the first column lists multiple direct drive vehicle speeds, the second column lists the weight assignments corresponding to each direct drive vehicle speed, the third column lists the fuel consumption per 100 kilometers obtained from the fuel consumption simulation tests for each direct drive vehicle speed, and the fourth column lists the comprehensive fuel consumption at the initial direct drive ratio obtained through weighted calculation based on the first three columns. By calculating the comprehensive fuel consumption corresponding to multiple initial direct drive ratios within the initial direct drive ratio range, the initial direct drive ratio with the lowest comprehensive fuel consumption is used as the target direct drive ratio.

[0049] In an embodiment of the present application, obtaining multiple initial direct drive ratios based on the initial direct drive ratio range includes: if the initial direct drive ratio range is 2.25 - 4.32, a direct drive ratio can be selected from the initial direct drive ratio range every 0.01 as the initial direct drive ratio. For example, the multiple initial direct drive ratios obtained from the initial direct drive ratio range of 2.25 - 4.3 are 2.25, 2.26, 2.27... 4.28, 4.29, and 4.3. The fuel consumption simulation tests are performed on each initial direct drive ratio in this embodiment to obtain the corresponding comprehensive fuel consumption, and the initial direct drive ratio with the lowest comprehensive fuel consumption is used as the target direct drive ratio.

[0050] Step S230, calculate the engine excitation frequencies at multiple direct drive vehicle speeds according to the target direct drive ratio.

[0051] In an embodiment of the present application, calculating the engine excitation frequencies at multiple direct drive vehicle speeds according to the target direct drive ratio includes: obtaining the wheel radius of the vehicle, and obtaining the engine speed at each direct drive vehicle speed based on the wheel radius, the target direct drive ratio, and multiple direct drive vehicle speeds; obtaining the engine excitation frequencies of multiple firing orders at each direct drive vehicle speed based on the engine speed and the preset firing order at each direct drive vehicle speed.

[0052] In an embodiment of the present application, the relationship between the engine speed and the vehicle speed is as follows:

[0053]

[0054] In Equation (3), u a is the vehicle driving speed (km / h); n is the engine speed (r / min); r is the wheel radius (m); i is the engine direct drive ratio. According to Equation (3), the engine speed at each direct drive vehicle speed can be calculated. Table 2 shows the engine speeds at each direct drive vehicle speed obtained when the target direct drive ratio is 3.2:

[0055] Table 2

[0056] Vehicle speed (km / h) Tire radius (m) Direct drive ratio Engine speed (rpm) 140 0.3815 3.2 3114.9 130 0.3815 3.2 2892.4 120 0.3815 3.2 2669.9 110 0.3815 3.2 2447.4 100 0.3815 3.2 2224.9 90 0.3815 3.2 2002.4 80 0.3815 3.2 1779.9 70 0.3815 3.2 1557.4 60 0.3815 3.2 1335.0

[0057] As can be seen from Table 2, when the target direct drive speed ratio is 3.2, the engine speeds corresponding to various direct drive vehicle speeds are obtained. After obtaining the engine speeds, the engine excitation frequencies corresponding to various firing orders can be obtained according to the engine speeds and the preset firing orders:

[0058]

[0059] In Equation (4), f is the engine excitation frequency, n is the engine speed, and k is the preset firing order. The preset firing order includes at least 0.5, 1, 1.5, 2, 2.5, 3, 3.5, and 4.

[0060] The excitation frequencies of multiple firing orders corresponding to various direct drive vehicle speeds at the calculated target direct drive speed ratio are shown in Table 3:

[0061] Table 3

[0062]

[0063] As can be seen from Table 3, when the target direct drive speed ratio is 3.2, the excitation frequencies of multiple firing orders corresponding to multiple direct drive vehicle speeds. In this embodiment, the engine is a four-cylinder four-stroke engine, so its main firing orders are the 2nd order and the 4th order. The excitation frequencies corresponding to various direct drive vehicle speeds of the 2nd order and the 4th order in Table 3 are used as the engine excitation frequencies for subsequent comparison with the vehicle modal frequency avoidance table of the whole vehicle.

[0064] Step S240, compare the engine excitation frequency with the excitation frequencies of multiple vehicle components in the pre-stored vehicle modal frequency avoidance table of the whole vehicle. If the comparison result meets the preset frequency avoidance condition, then use the target direct drive speed ratio as the direct drive speed ratio determination result.

[0065] In an embodiment of the present application, after comparing the engine excitation frequency with the excitation frequencies of multiple vehicle components in the pre-stored vehicle modal frequency avoidance table of the whole vehicle, it further includes: if the comparison result shows that the difference between the excitation frequency of one or more vehicle components in the vehicle modal frequency avoidance table and the engine excitation frequency is less than the preset difference threshold, then use one or more vehicle components as the components to be optimized; after replacing or adjusting the components to be optimized, update the vehicle modal frequency avoidance table of the whole vehicle, and re-compare based on the updated vehicle modal frequency avoidance table and the engine excitation frequency to make the re-comparison result meet the preset frequency avoidance condition.

[0066] In one embodiment of the present application, after one or more vehicle components are taken as components to be optimized, the following steps are further included: If the components to be optimized cannot be replaced or adjusted, a secondary direct drive speed ratio is obtained according to the results of fuel consumption simulation tests, and the secondary direct drive speed ratio is used as the new target direct drive speed ratio; the engine excitation frequency at the new target direct drive speed ratio is obtained according to the new target direct drive speed ratio, and the engine excitation frequency at the new target direct drive speed ratio is compared again with the excitation frequencies of multiple vehicle components in the vehicle modal frequency avoidance table. If the result of the re-comparison meets the preset frequency avoidance condition, the new target direct drive speed ratio is used as the determined result of the direct drive speed ratio.

[0067] In one embodiment of the present application, comparing the engine excitation frequency with the excitation frequencies of multiple vehicle components in the pre-stored vehicle modal frequency avoidance table includes: If the engine is a four-cylinder four-stroke engine, the second-order engine excitation frequency and the fourth-order engine excitation frequency are compared with the excitation frequencies of vehicle components in the vehicle modal frequency avoidance table; the multiple firing orders at least include the first order, the second order, the third order, and the fourth order.

[0068] In one embodiment of the present application, according to the CAE analysis of the whole vehicle, a vehicle modal frequency avoidance table is obtained, and frequency avoidance optimization is performed on the vehicle based on the engine frequency and the vehicle modal frequency avoidance table. If there are vehicle components with engine frequency coupling, the vehicle components are optimized first. If the vehicle components cannot be optimized, the target direct drive speed ratio is re-selected based on the results of fuel consumption simulation tests, and the above steps of analysis are repeated until the target direct drive speed ratio simultaneously meets the requirements of fuel economy and NVH. Table 4 is an exemplary vehicle modal frequency avoidance table of a certain vehicle model:

[0069] Table 4

[0070]

[0071] Compare the excitation frequencies corresponding to each vehicle component in Table 4 with the engine excitation frequency obtained in step S230. If there are vehicle components with similar frequencies (it is considered that the frequencies are similar if the difference between the excitation frequency of the vehicle component and the engine excitation frequency is less than the preset difference threshold), the vehicle component is taken as the component to be optimized. When there are components to be optimized, first select to replace or adjust the components to be optimized so that the difference between the excitation frequency of the components to be optimized and the engine excitation frequency is greater than or equal to the preset difference threshold (meeting the preset frequency avoidance condition). If the components to be optimized cannot be replaced or adjusted, it is necessary to re-select the target direct drive speed ratio from the results of fuel consumption simulation tests based on step S220. In this embodiment, the initial direct drive speed ratio with the second lowest comprehensive fuel consumption can be used as the new target direct drive speed ratio.

[0072] Please refer to Figure 3 , Figure 3It is a schematic diagram of the direct drive speed ratio optimization process shown in an exemplary embodiment of the present application. In an embodiment of the present application, Matlab / Simulink and AVL Cruise are used for co-simulation to find the direct drive speed ratio that minimizes the comprehensive fuel consumption rate under the condition of 60 - 140 KPH as the target direct drive speed ratio. The optimization process is as follows Figure 3 shown: Establish a powertrain and vehicle model in AVL cruise, input the power demand in Simulink to determine the direct drive speed ratio range, obtain the initial speed ratio from the direct drive speed ratio range, and transmit the initial speed ratio to the vehicle model in AVL cruise for simulation operation. The simulation operation includes cruising at a constant speed of 60 - 140 KPH, running once every 10 KPH, calculating the weighted value of each direct drive vehicle speed based on the actual usage conditions, and thus obtaining the comprehensive fuel consumption at the initial speed ratio. If the comprehensive fuel consumption at the initial speed ratio is the smallest, replace the initial speed ratio of the previous iteration. If the comprehensive fuel consumption is not the smallest, discard the speed ratio of this iteration. If the optimization has not ended, continue to obtain the next iteration's initial speed ratio from the direct drive speed ratio range and repeat the above simulation steps until the optimization ends, and output the best engine direct drive speed ratio with the smallest comprehensive fuel consumption as the target direct drive speed ratio. In this embodiment, AVL cruise is a software for simulating fuel economy and emission performance, mainly used for the development of vehicle powertrains and engines. Simulink is a visualization simulation tool in MATLAB. Simulink is a block diagram environment for multi-domain simulation and model-based design, supporting system design, simulation, automatic code generation, and continuous testing and verification of embedded systems.

[0073] In the embodiment of the present application, the vehicle speed statistical frequency is obtained by counting the usage frequencies of each direct drive vehicle speed condition, and weights are assigned to the direct drive vehicle speeds based on the vehicle speed statistical frequency, thus realizing the definition and optimization process of the cruise condition fuel economy index based on the actual usage frequency of the whole vehicle. On the premise of meeting the vehicle power performance, the fuel economy in the engine direct drive mode is optimized.

[0074] In the embodiment of the present application, the engine excitation frequencies of multiple firing orders at each direct drive vehicle speed are calculated, which can be applied to various vehicle models and various engines, increasing the versatility of this method.

[0075] In the embodiment of the present application, when optimizing the frequency avoidance of the vehicle, the influence of the modal frequencies of the key components of the whole vehicle on NVH is considered, and the NVH resonance risk in the engine direct drive mode is avoided in advance, improving the NVH performance and ride comfort.

[0076] In an embodiment of the present application, if the vehicle components cannot be optimized, the target direct drive ratio is optimized, comprehensively considering the power performance, fuel economy, and vehicle NVH performance of the engine.

[0077] In an embodiment of the present application, the engine direct drive ratio matching is combined with the vehicle NVH matching, considering the influence of the engine excitation frequency on the modes of key vehicle components, avoiding the frequency coupling between the vehicle components and the engine, and improving the comfort of the vehicle.

[0078] In an embodiment of the present application, when selecting the initial direct drive ratio range, it is determined not only based on the power demand but also considering the engine economic torque range, so as to determine the engine direct drive ratio of the hybrid vehicle model that takes into account both fuel economy and NVH performance.

[0079] Please refer to Figure 4 , Figure 4 which is a block diagram of a vehicle engine direct drive ratio determination device shown in an exemplary embodiment of the present application. As Figure 4 shown, the exemplary vehicle engine direct drive ratio determination device includes an information input module 401, a fuel consumption simulation module 402, a frequency calculation module 403, and a frequency comparison module 404.

[0080] The information input module 401 is configured to obtain the initial direct drive ratio range and multiple direct drive vehicle speeds. The initial direct drive ratio range is determined based on the preset power demand of the engine, and the multiple direct drive vehicle speeds are determined based on the vehicle speed range in the engine direct drive mode.

[0081] The fuel consumption simulation module 402 is configured to perform a fuel consumption simulation test on the vehicle based on the initial direct drive ratio range and multiple direct drive vehicle speeds, and obtain the target direct drive ratio according to the results of the fuel consumption simulation test.

[0082] The frequency calculation module 403 is configured to calculate the engine excitation frequency at multiple direct drive vehicle speeds according to the target direct drive ratio.

[0083] The frequency comparison module 404 is configured to compare the engine excitation frequency with the excitation frequencies of multiple vehicle components in the pre-stored vehicle modal anti-resonance table. If the comparison result meets the preset anti-resonance condition, the target direct drive ratio is used as the direct drive ratio determination result.

[0084] Figure 5 shows a schematic structural diagram of a computer system of an electronic device suitable for implementing the embodiments of the present application. It should be noted that Figure 5 the computer system 500 of the electronic device shown is only an example and should not impose any limitation on the functions and usage scope of the embodiments of the present application.

[0085] As Figure 5As shown, the computer system 500 includes a Central Processing Unit (CPU) 501, which can perform various appropriate actions and processes according to the program stored in the Read-Only Memory (ROM) 502 or the program loaded from the storage section 508 into the Random Access Memory (RAM) 503, such as executing the methods described in the above embodiments. In the RAM 503, various programs and data required for system operation are also stored. The CPU 501, ROM 502, and RAM 503 are connected to each other via a bus 504. An Input / Output (I / O) interface 505 is also connected to the bus 504.

[0086] The following components are connected to the I / O interface 505: an input section 506 including a keyboard, a mouse, etc.; an output section 507 including, for example, a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD), etc., and a speaker, etc.; a storage section 508 including a hard disk, etc.; and a communication section 509 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section 509 performs communication processing via a network such as the Internet. A drive 510 is also connected to the I / O interface 505 as needed. A removable medium 511, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 510 as needed so that a computer program read from it can be installed into the storage section 508 as needed.

[0087] Specifically, according to the embodiments of the present application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, the embodiments of the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a computer program for executing the methods shown in the flowcharts. In such an embodiment, the computer program can be downloaded and installed from the network via the communication section 509, and / or installed from the removable medium 511. When the computer program is executed by the Central Processing Unit (CPU) 501, various functions defined in the system of the present application are executed.

[0088] It should be noted that the computer-readable medium shown in the embodiments of the present application can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable computer program. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. The computer program contained on the computer-readable medium can be transmitted by any appropriate medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0089] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present application. Among them, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the above module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, and the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0090] The units involved in the embodiments described in this application can be implemented in software or in hardware, and the described units can also be provided in a processor. Among them, the names of these units do not, in some cases, constitute a limitation on the units themselves.

[0091] Another aspect of this application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor of a computer, the computer is caused to execute the vehicle engine direct drive ratio determination method as described above. The computer-readable storage medium can be included in the electronic device described in the above embodiments, or can exist alone without being assembled into the electronic device.

[0092] Another aspect of this application also provides a computer program product or a computer program. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the vehicle engine direct drive ratio determination method provided in each of the above embodiments.

[0093] The above embodiments are only used to exemplarily illustrate the principles and effects of this application, rather than to limit this application. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed in this application should still be covered by the claims of this application.

Claims

1. A method for determining a direct drive speed ratio of a vehicle engine, characterized in that: The method for determining the direct drive speed ratio of the engine comprises: Acquire an initial direct-drive speed ratio range and a plurality of direct-drive vehicle speeds, wherein the initial direct-drive speed ratio range is determined based on a preset power requirement of the engine, and the plurality of direct-drive vehicle speeds are determined based on a vehicle speed range in a direct-drive mode of the engine; performing a fuel consumption simulation test of the vehicle based on the initial direct drive speed ratio range and the plurality of direct drive vehicle speeds, and obtaining a target direct drive speed ratio according to a result of the fuel consumption simulation test; calculating an engine excitation frequency of the engine at the plurality of direct drive vehicle speeds according to the target direct drive speed ratio; The engine excitation frequency is compared with the excitation frequencies of multiple vehicle components in a pre-stored vehicle modal frequency avoidance table. If the comparison result meets the preset frequency avoidance condition, the target direct drive speed ratio is used as the direct drive speed ratio determination result.

2. The method for determining the direct drive speed ratio of a vehicle engine according to claim 1, characterized in that: Performing a fuel consumption simulation test on the vehicle based on the initial direct drive speed ratio range and the multiple direct drive vehicle speeds, and obtaining a target direct drive speed ratio according to the result of the fuel consumption simulation test includes: Obtaining the vehicle speed statistical frequency of each direct-drive vehicle speed, and assigning a weight to each direct-drive vehicle speed based on the vehicle speed statistical frequency; Based on the initial direct drive speed ratio range, a plurality of initial direct drive speed ratios are obtained, and a fuel consumption simulation test is performed on each initial direct drive speed ratio to obtain the fuel consumption per 100 kilometers corresponding to each direct drive vehicle speed under each initial direct drive speed ratio; According to the fuel consumption per 100 kilometers corresponding to each direct-drive vehicle speed under each initial direct-drive speed ratio and the weight corresponding to each direct-drive vehicle speed, the comprehensive fuel consumption corresponding to each initial direct-drive speed ratio is obtained; The initial direct drive speed ratio with the lowest comprehensive fuel consumption is used as the target direct drive speed ratio.

3. The method for determining the direct drive speed ratio of a vehicle engine according to claim 1, characterized in that: Calculating the engine excitation frequency of the engine at the plurality of direct drive vehicle speeds according to the target direct drive speed ratio comprises: Acquire a wheel radius of the vehicle, and obtain an engine speed at each direct drive vehicle speed according to the wheel radius, the target direct drive speed ratio, and the plurality of direct drive vehicle speeds; The engine excitation frequencies of the multiple ignition orders at each direct-drive vehicle speed are obtained based on the engine speed at each direct-drive vehicle speed and the preset ignition order.

4. The method for determining the direct drive speed ratio of a vehicle engine according to any one of claims 1 to 3, characterized in that: After comparing the engine excitation frequency with the excitation frequencies of multiple vehicle components in a pre-stored vehicle modal frequency avoidance table, the method further includes: If the comparison result is that the difference between the excitation frequency of one or more vehicle components in the whole vehicle modal frequency avoidance table and the engine excitation frequency is less than a preset difference threshold, the one or more vehicle components are used as components to be optimized, and the preset frequency avoidance condition includes that the comparison result is that the difference between the excitation frequency of the multiple vehicle components in the whole vehicle modal frequency avoidance table and the engine excitation frequency is greater than or equal to the preset difference threshold; After the component to be optimized is replaced or adjusted, the whole vehicle modal frequency avoidance table is updated, and the updated whole vehicle modal frequency avoidance table is re-compared with the engine excitation frequency so that the re-comparison result meets the preset frequency avoidance condition.

5. The method for determining the direct drive speed ratio of a vehicle engine according to claim 4, characterized in that: After selecting the one or more vehicle components as components to be optimized, the following step further includes: If the component to be optimized cannot be replaced or adjusted, a second-selected direct drive speed ratio is obtained according to the result of the fuel consumption simulation test, and the second-selected direct drive speed ratio is used as a new target direct drive speed ratio; The engine excitation frequency at the new target direct drive speed ratio is obtained according to the new target direct drive speed ratio, and the engine excitation frequency at the new target direct drive speed ratio is compared again with the excitation frequencies of multiple vehicle components in the whole vehicle modal frequency avoidance table. If the re-comparison result meets the preset frequency avoidance condition, the new target direct drive speed ratio is used as the direct drive speed ratio determination result.

6. The method for determining the direct drive speed ratio of a vehicle engine according to claim 3, characterized in that: Comparing the engine excitation frequency with the excitation frequencies of multiple vehicle components in a pre-stored vehicle modal frequency avoidance table includes: If the engine is a four-cylinder four-stroke, the second-order engine excitation frequency and the fourth-order engine excitation frequency are compared with the excitation frequency of the vehicle components in the whole vehicle modal frequency avoidance table; The multiple ignition orders include at least first order, second order, third order and fourth order.

7. The method for determining the direct drive speed ratio of a vehicle engine according to any one of claims 1 to 3, characterized in that: After obtaining the initial direct drive speed ratio range and multiple direct drive vehicle speeds, the following steps are also included: Acquire a wheel radius of the vehicle, and obtain a maximum engine speed and a minimum engine speed according to the wheel radius, the target direct drive speed ratio, and the plurality of direct drive vehicle speeds; Performing a bench test on the engine to obtain a universal characteristic curve of the engine, and determining an economic torque range of the engine based on the universal characteristic curve; Obtaining an economic maximum speed and an economic minimum speed according to the engine economic torque range; If the maximum engine speed is greater than the economic maximum speed or the minimum engine speed is less than the economic minimum speed, the initial direct drive speed ratio range is adjusted so that the maximum engine speed is less than or equal to the economic maximum speed and the minimum engine speed is greater than or equal to the economic minimum speed.

8. A vehicle engine direct drive speed ratio determination device, characterized in that: The vehicle engine direct drive speed ratio determining device comprises: An information input module, used to obtain an initial direct drive speed ratio range and a plurality of direct drive vehicle speeds, wherein the initial direct drive speed ratio range is determined based on a preset power requirement of the engine, and the plurality of direct drive vehicle speeds are determined based on a vehicle speed range in a direct drive mode of the engine; a fuel consumption simulation module, configured to perform a fuel consumption simulation test of the vehicle based on the initial direct drive speed ratio range and the plurality of direct drive vehicle speeds, and obtain a target direct drive speed ratio according to a result of the fuel consumption simulation test; a frequency calculation module, configured to calculate an engine excitation frequency of the engine at the plurality of direct drive vehicle speeds according to the target direct drive speed ratio; The frequency comparison module is used to compare the engine excitation frequency with the excitation frequencies of multiple vehicle components in a pre-stored vehicle modal frequency avoidance table. If the comparison result meets the preset frequency avoidance condition, the target direct drive speed ratio is used as the direct drive speed ratio determination result.

9. An electronic device, characterized in that: The electronic device comprises: one or more processors; A storage device for storing one or more programs, which, when executed by the one or more processors, enables the electronic device to implement the vehicle engine direct drive speed ratio determination method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed by a processor of a computer, the computer is caused to execute a method for determining a direct drive speed ratio of a vehicle engine as claimed in any one of claims 1 to 7.

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