Method and device for determining parameters of hybrid vehicle

Abstract

The invention provides a method and device for determining parameters of a hybrid vehicle, the method is applied to the technical field of vehicle control, and the method comprises the steps that an engine optimal performance curve and a required vehicle speed range of the hybrid vehicle are obtained; based on the optimal performance curve, the theoretical total speed ratio of the hybrid vehicle is determined; and based on the required vehicle speed range, the theoretical total speed ratio is corrected, and the target total speed ratio of the hybrid vehicle at the highest gear is obtained. According to the method, the parameters of the transmission in the hybrid vehicle are determined, and the fuel efficiency of the hybrid vehicle is improved.

Description

Technical Field

[0001] This application relates to the automotive field, and more specifically, to a method and apparatus for determining parameters of a hybrid vehicle in the field of vehicle control technology. Background Technology

[0002] With the continuous development of the automotive industry, vehicle energy efficiency has become a core objective of design optimization. In the current technology, the parameter settings for the engines and transmissions of hybrid vehicles do not take into account the vehicle's driving scenarios and user needs, which can easily lead to the power provided by the vehicle's gear speed range being unable to adapt to the vehicle speed, resulting in low fuel efficiency.

[0003] Therefore, determining the parameters of the transmission in a hybrid vehicle while considering fuel efficiency is a problem that needs to be solved. Summary of the Invention

[0004] This application provides a method and apparatus for determining parameters of a hybrid vehicle. The method determines the parameters of the transmission in the hybrid vehicle, thereby improving the fuel efficiency of the hybrid vehicle.

[0005] Firstly, a method for determining parameters of a hybrid vehicle is provided, the method comprising:

[0006] Obtain the optimal engine performance curve and required speed range of the hybrid vehicle; based on the optimal performance curve, determine the theoretical total speed ratio of the hybrid vehicle; based on the required speed range, correct the theoretical total speed ratio to obtain the target total speed ratio of the hybrid vehicle in the highest gear.

[0007] In the embodiments of this application, by obtaining the optimal performance curve of the hybrid vehicle's engine and the required speed range, the theoretical total speed ratio of the hybrid vehicle is determined based on the optimal performance curve, thus determining a speed ratio that matches the engine's efficient operating state. Based on the required speed range, the theoretical total speed ratio is corrected to obtain the target total speed ratio of the hybrid vehicle. Since the optimal performance curve and the required speed range are used to determine the theoretical total speed ratio with the highest energy transfer efficiency for the hybrid vehicle under pure engine drive conditions, and the correction of the theoretical total speed ratio based on the required speed range ensures that the hybrid vehicle travels within the required speed range at the optimal speed ratio with the highest energy transfer efficiency, thereby improving the fuel efficiency of the hybrid vehicle.

[0008] In conjunction with the first aspect, in some possible implementations, the theoretical total gear ratio is corrected based on the required vehicle speed range to obtain the target total gear ratio of the hybrid vehicle in the highest gear, including:

[0009] Based on the theoretical total speed ratio and the engine's economic speed, the target vehicle speed range is determined, where the engine's economic speed includes the first target speed and the second target speed. Based on the target vehicle speed range and the required vehicle speed range, the theoretical total speed ratio is corrected to obtain the target total speed ratio when the gear is in the highest gear.

[0010] In the embodiments of this application, the theoretical total speed ratio and the economic speed of the engine can be determined, and the vehicle speed range corresponding to the economic speed of the engine under the theoretical total speed ratio can be determined. Based on the required vehicle speed range and the vehicle speed range corresponding to the economic speed, the theoretical total speed ratio is corrected to ensure that the engine speed is within the economic speed range when the vehicle is driving within the user's required vehicle speed range, thereby improving fuel efficiency.

[0011] Combining the first aspect and the above implementation methods, in some possible implementation methods, based on the optimal performance curve, the theoretical total speed ratio of the hybrid vehicle is determined, including:

[0012] The economic speed of the engine is determined based on the engine's economic speed range, which includes a first target speed and a second target speed. Based on the optimal performance curve and the first target speed, a first economic vehicle speed is determined. Based on the first economic vehicle speed, a first gear ratio is determined. Based on the optimal performance curve and the second target speed, a second economic vehicle speed is determined. Based on the second economic vehicle speed, a second gear ratio is determined. The gear ratio with the smaller value between the first gear ratio and the second gear ratio is determined as the theoretical total gear ratio.

[0013] In the embodiments of this application, the economic speed of the engine is determined based on the economic speed range of the engine; the first economic speed and the second economic speed are determined based on the economic speed and the optimal performance curve; two speed ratios are determined based on the first economic speed and the second economic speed, and the speed ratio with the smaller value is determined as the theoretical total speed ratio; this can ensure that the engine outputs higher torque at a lower speed, and meets the driving conditions required by the user while saving fuel consumption.

[0014] Combining the first aspect and the above implementation methods, in some possible implementation methods, the theoretical total gear ratio is corrected based on the target vehicle speed range and the required vehicle speed range to obtain the target total gear ratio of the hybrid vehicle in the highest gear, including:

[0015] If the target speed range matches the required speed range, the correction factor is set to 1. The theoretical total speed ratio is then corrected based on this correction factor to obtain the target total speed ratio of the hybrid vehicle in the highest gear. If the target speed range does not match the required speed range, the correction factor is set to the target difference between the second-highest gear and the highest gear. The theoretical total speed ratio is then corrected based on this correction factor to obtain the target total speed ratio of the hybrid vehicle in the highest gear.

[0016] In the embodiments of this application, if the target speed range matches the required speed range, that is, under the theoretical total speed ratio, the speed range corresponding to the engine's economic speed is close to the user's required speed range, and the current value of the theoretical total speed ratio can ensure that the engine speed is within the economic speed range when the vehicle is driving within the user's required speed range, the correction coefficient is determined to be 1. Based on the correction coefficient and the theoretical total speed ratio, the target total speed ratio of the hybrid vehicle in the highest gear is obtained. If the target speed range does not match the required speed range, then under the theoretical total speed ratio, the speed range corresponding to the engine's economic speed differs significantly from the user's required speed range. In this case, the correction coefficient is determined to be the target level difference. Based on the correction coefficient, the theoretical total speed ratio is corrected to obtain the target total speed ratio. By setting the level difference, the theoretical total speed ratio can be corrected so that when the hybrid vehicle is driving within the user's required speed range, the engine will operate in the most fuel-efficient manner.

[0017] Combining the first aspect and the above implementation methods, in some possible implementation methods, the target difference is obtained through the following steps:

[0018] The minimum grade difference is determined based on the maximum value within the required vehicle speed range and the maximum value between the first and second target speeds; the maximum grade difference is determined based on the minimum value within the required vehicle speed range and the minimum value between the first and second target speeds; the grade difference range is determined based on the minimum and maximum grade differences; and the target grade difference is determined based on the grade difference range.

[0019] In the embodiments of this application, if the target vehicle speed range does not match the required vehicle speed range, the grade difference range is determined based on the required vehicle speed range and the economic speed. A suitable grade difference range can be determined. Based on the grade difference range, the target total speed ratio can be further determined, so that the target total speed ratio of the hybrid vehicle in the highest gear can make the engine operate in the most fuel-efficient way when the hybrid vehicle is driving within the speed range required by the user.

[0020] Combining the first aspect and the above implementation methods, in some possible implementation methods, a first economic vehicle speed is determined based on the optimal performance curve and a first target speed, and a second economic vehicle speed is determined based on the optimal performance curve and a second target speed, including:

[0021] The minimum efficiency direct drive line is determined based on the optimal performance curve and the engine's thermal efficiency. This minimum efficiency direct drive line is used to characterize the boundary between the engine's thermal efficiency in direct drive mode and parallel electric drive mode. Based on the minimum efficiency direct drive line and the first target speed, the first target power is determined. Based on the first target power and driving resistance, the first economic speed is determined. Based on the minimum efficiency direct drive line and the second target speed, the second target power is determined. Based on the second target power and driving resistance, the second economic speed is determined.

[0022] In the embodiments of this application, the lowest efficiency direct drive line is determined based on the optimal performance curve and the engine's thermal efficiency, which can determine the high efficiency operating conditions of the engine in direct drive mode. Based on the lowest efficiency direct drive line, the first target speed, and the second target speed, the target power range is determined, which can ensure the power range corresponding to the engine under high fuel efficiency conditions. Based on the relationship between the target power range and driving resistance, the target vehicle speed range is further determined, which can accurately calculate the vehicle speed range corresponding to the engine under high fuel efficiency conditions, thus improving the accuracy of the calculation process.

[0023] In combination with the first aspect and the above implementation methods, some possible implementation methods also include:

[0024] The final drive ratio of the hybrid vehicle's transmission is determined based on the target total gear ratio and the preset gear ratio of the highest gear.

[0025] In the embodiments of this application, the final drive ratio of the hybrid vehicle is determined based on the preset highest gear ratio and the target total gear ratio. This allows for the setting of a reasonable final drive ratio, ensuring that the hybrid vehicle can output sufficient power to meet the user's required speed range at the corresponding target gear ratio.

[0026] Combining the first aspect and the above implementation methods, in some possible implementation methods, the minimum efficiency line for direct drive is determined based on the optimal performance curve and the engine's thermal efficiency, including:

[0027] The target speed range of the engine is determined, and multiple target torque ranges are determined based on the target speed range and the optimal performance curve. The target speed range is the speed range from the minimum speed to the maximum speed of the engine. The target torque range is the torque range from the minimum torque to the maximum torque that the engine can output at any speed within the target speed range. The maximum torque of the engine at any speed within the target speed range is obtained based on the torque corresponding to that speed on the optimal performance curve. Based on the engine's thermal efficiency, the target speed range, and the multiple target torque ranges, the efficiency direct drive minimum line is determined.

[0028] In the embodiments of this application, by combining the engine's optimal performance curve and thermal efficiency, and comprehensively considering the range of the target speed range and the target torque range, the engine's working efficiency under different operating conditions can be determined, the lowest efficiency direct drive line can be determined, and the engine's high-efficiency operating range can be divided to guide the reasonable setting of the vehicle's overall speed ratio, so as to save fuel consumption of hybrid vehicles during driving.

[0029] Combining the first aspect and the above implementation methods, in some possible implementation methods, based on the engine's thermal efficiency, target speed range, and multiple target torque ranges, the minimum efficiency direct drive line is determined, including:

[0030] Based on the target speed range and multiple target torque ranges, multiple operating points are determined. Each operating point is obtained based on any speed within the target speed range and any torque within the corresponding target torque range. The first efficiency in a first mode and the second efficiency in a second mode are calculated for each operating point. The first mode includes engine direct drive mode, and the first efficiency is the thermal efficiency of the engine operating in the first mode. The second mode includes parallel electric drive mode, which includes parallel power generation mode and pure electric drive mode, and the second efficiency is the thermal efficiency of the engine operating in the second mode. Based on the first and second efficiencies of each operating point, operating points where the first efficiency is less than or equal to the second efficiency are determined as target operating points. Based on all target operating points, the minimum efficiency line for direct drive is determined.

[0031] In the embodiments of this application, the efficiency of the engine operating points under different modes can be accurately analyzed and compared. Based on the relationship between the first efficiency and the second efficiency, the target operating points can be reasonably screened, and the lowest efficiency direct drive line can be determined for subsequent calculation of the appropriate overall vehicle speed ratio. By scientifically dividing the operating boundaries of the engine direct drive mode and the parallel electric drive mode, it can be ensured that the engine works in the high-efficiency range, thereby achieving the optimal matching of the vehicle power system and achieving the goal of reducing fuel consumption and extending engine life.

[0032] Secondly, a device for determining parameters of a hybrid vehicle is provided, the device comprising:

[0033] The acquisition module is used to obtain the optimal performance curve of the engine and the required vehicle speed range of the hybrid vehicle.

[0034] The processing module is used to determine the theoretical total speed ratio of the hybrid vehicle based on the optimal performance curve; and to correct the theoretical total speed ratio based on the required vehicle speed range to obtain the target total speed ratio of the hybrid vehicle in the highest gear.

[0035] It should be understood that the extensions, limitations, explanations and descriptions of the relevant content in the first aspect above also apply to the same content in the second aspect. Attached Figure Description

[0036] Figure 1 This is a schematic flowchart illustrating a method for determining parameters of a hybrid vehicle provided in an embodiment of this application;

[0037] Figure 2 This is a schematic diagram of the method for determining the lowest efficiency direct drive line provided in the embodiments of this application;

[0038] Figure 3 This is a schematic flowchart illustrating another method for determining hybrid vehicle parameters provided in an embodiment of this application;

[0039] Figure 4This is a schematic diagram of the structure of a device for determining parameters of a hybrid vehicle provided in an embodiment of this application. Detailed Implementation

[0040] The technical solutions in this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0041] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0042] In order to illustrate the technical solutions provided in the embodiments of this application, some terms involved in the embodiments of this application will be introduced first.

[0043] Hybrid vehicles, also known as hybrid electric vehicles (HEVs), combine two power sources: an internal combustion engine and a drive electric motor. They can intelligently switch or work in tandem depending on driving conditions to improve fuel efficiency and reduce emissions. Hybrid vehicles typically have the following modes: pure electric drive mode (EV), parallel generator mode, parallel power assist drive mode, and engine drive mode.

[0044] Pure electric drive mode: The hybrid vehicle is entirely driven by the electric motor, with the engine off. The vehicle's power comes from the battery, suitable for low-speed driving or short-distance commuting.

[0045] Parallel power generation mode: The engine and motor work in parallel. In this mode, the engine serves as the primary driving power source, while simultaneously driving the generator to generate electricity. The generator converts mechanical energy into electrical energy to power the motor, and also charges the battery, either directly or indirectly.

[0046] Parallel-assisted drive mode: The engine and electric motor jointly drive the wheels. The engine provides the main power, while the electric motor provides additional torque support, improving the overall power output.

[0047] Engine direct drive mode: The engine provides the driving force, and the electric motor is in standby or stopped state, which is suitable for high-speed cruising or long-distance driving conditions.

[0048] With advancements in vehicle-related technologies, vehicle powertrain systems are gradually transitioning from traditional gasoline-powered vehicles to hybrid electric vehicles. Hybrid vehicles can intelligently switch or coordinate their operation based on different driving conditions to improve fuel efficiency and reduce emissions. In the power control of hybrid vehicles, gear ratio design is a key factor affecting vehicle performance. A reasonable gear ratio allows the engine to operate within its economical speed range while meeting the user's needs for different vehicle speeds, thereby improving fuel economy and driving comfort. However, current gear ratio designs are often based solely on specific operating conditions or empirical parameters, failing to fully consider the user's actual vehicle speed requirements and the dynamic characteristics of the engine's economical speed range. This results in fuel efficiency and driving experience not being optimal under certain driving conditions.

[0049] In view of this, this solution provides a method and apparatus for determining hybrid vehicle parameters: by acquiring the optimal performance curve of the hybrid vehicle's engine and the required speed range, the target speed range of the hybrid vehicle is determined based on the optimal performance curve, thus determining a target speed range that matches the engine's efficient operating state; based on the target speed range and the required speed range, the theoretical total speed ratio corresponding to the required speed range is determined. Since the target speed range is dynamically determined based on the optimal performance curve, the speed range with high energy transfer efficiency for the hybrid vehicle under pure engine drive conditions can be identified. Determining the theoretical total speed ratio based on the target speed range and the required speed range ensures that the hybrid vehicle operates within the required speed range at the optimal speed ratio with high energy transfer efficiency, thereby improving fuel efficiency.

[0050] The following is combined Figure 1 This application provides a detailed description of a method for determining parameters of a hybrid vehicle.

[0051] Figure 1 This is a schematic flowchart illustrating a method for determining parameters of a hybrid vehicle provided in an embodiment of this application. Figure 1 As shown, method 100 includes steps S110 to S130, which are described in detail below.

[0052] S110: Obtain the optimal engine performance curve and required speed range for the hybrid vehicle.

[0053] The Optimal Performance Curve (OPT) is a line connecting the points where an engine achieves the lowest fuel consumption rate under different operating conditions. It describes the engine's fuel economy and power output capability under various conditions. Specifically, the OPT curve typically plots engine speed on the horizontal axis and output torque on the vertical axis. Certain regions within the curve represent operating ranges with high fuel efficiency or high energy output. These regions are called the engine's high-efficiency operating range, indicating that the engine's energy conversion efficiency is highest and fuel consumption is lowest under these conditions.

[0054] For example, the engine OPT line of a hybrid vehicle can be obtained through engine bench testing: the engine is placed on a test bench and run at different speeds and torques. By measuring the fuel consumption and output power per unit time, the region where the engine operates efficiently is determined, and the optimal performance curve is obtained. The required vehicle speed range can be determined by the user's usual vehicle speed. For example, if the user's driving needs are high load and high-speed cruising, and the user's driving needs determine that the usual driving section of the hybrid vehicle is a national highway, the required vehicle speed range can be further determined to be 60km / h to 80km / h.

[0055] Optionally, the required speed range can be obtained based on the user's driving data statistics. For example, by using big data analysis to extract the user's most frequently driven speed range as 50km / h to 60km / h, the required speed range can be determined based on this speed range.

[0056] S120. Based on the optimal performance curve, determine the theoretical total speed ratio of the hybrid vehicle.

[0057] The speed ratio is used to represent the relationship between the engine speed and the wheel speed, that is, the transmission ratio of the vehicle.

[0058] In one implementation, the above method includes:

[0059] The economic speed of the engine is determined based on the engine's economic speed range, which includes a first target speed and a second target speed. Based on the optimal performance curve and the first target speed, a first economic vehicle speed is determined. Based on the first economic vehicle speed, a first gear ratio is determined. Based on the optimal performance curve and the second target speed, a second economic vehicle speed is determined. Based on the second economic vehicle speed, a second gear ratio is determined. The gear ratio with the smaller value between the first gear ratio and the second gear ratio is determined as the theoretical total gear ratio.

[0060] In embodiments of this application, the first speed ratio and the second speed ratio can be determined based on the following formula:

[0061]

[0062] Where 0.377 is the conversion coefficient from angular velocity to linear velocity, R is the wheel radius, and i is the speed ratio.

[0063] For example, the first economical speed can be 70 km / h, the second economical speed can be 80 km / h, the first target speed can be 1000 rpm, and the second target speed can be 1300 rpm, that is, the economical speed range is 1000 rpm to 1300 rpm, the wheel radius can be 0.5 m, the first speed ratio i1 = 0.377 × 1000 × 0.5 / 70 = 2.69, and the second speed ratio i2 = 0.377 × 1300 × 0.5 / 80 = 3.06; since i1 is less than i2, i1 is determined as the theoretical total speed ratio, and the target total speed ratio is determined based on i1.

[0064] It should be understood that the above embodiments are exemplified by a conversion factor of 0.377 and a wheel radius of 0.5m. Professionals can make different settings according to specific circumstances. This is only an example and is not a specific limitation.

[0065] In the above scheme, the economic speed of the engine is determined based on the economic speed range of the engine; the first economic speed and the second economic speed are determined based on the economic speed and the optimal performance curve; two speed ratios are determined based on the first economic speed and the second economic speed, and the speed ratio with the smaller value is determined as the theoretical total speed ratio; this can ensure that the engine outputs higher torque at lower speeds, and meets the driving conditions required by users while saving fuel consumption.

[0066] In one implementation, the above method includes:

[0067] The minimum efficiency direct drive line is determined based on the optimal performance curve and the engine's thermal efficiency. This minimum efficiency direct drive line is used to characterize the boundary between the engine's thermal efficiency in direct drive mode and parallel electric drive mode. Based on the minimum efficiency direct drive line and the first target speed, the first target power is determined. Based on the first target power and driving resistance, the first economic speed is determined. Based on the minimum efficiency direct drive line and the second target speed, the second target power is determined. Based on the second target power and driving resistance, the second economic speed is determined.

[0068] In the embodiments of this application, the power range can be determined based on the minimum efficiency direct drive line and the economic speed range. For example, P = N·T, where P is the power, N is the economic speed, and T is the torque corresponding to the economic speed. Then, the target vehicle speed range can be determined based on P = F·v, where F is the driving resistance and v is the vehicle speed. F can be equal to the sum of rolling resistance and air resistance.

[0069] For example, the first target speed can be 1000 rpm, and the second target speed can be 1300 rpm, that is, the economic speed range is 1000 rpm to 1300 rpm. Based on the first target speed and the lowest efficiency direct drive line, the first target power P1 corresponding to 1000 rpm can be determined; and based on the second target speed and the lowest efficiency direct drive line, the second target power P2 corresponding to 1300 rpm can be determined. P1 to P2 is the target power range. The driving resistance corresponding to P1 and P2 can be calculated respectively to determine the first economic vehicle speed v1 corresponding to 1000 rpm and the second economic vehicle speed v2 corresponding to 1300 rpm. v1 to v2 is the target vehicle speed range.

[0070] In the above scheme, the minimum efficiency line for direct drive is determined based on the optimal performance curve and the engine's thermal efficiency, which can identify the high-efficiency operating conditions of the engine in direct drive mode. Based on the minimum efficiency line for direct drive, the first target speed, and the second target speed, the target power range is determined, which can ensure the power range corresponding to the engine under high fuel efficiency conditions. Based on the relationship between the target power range and driving resistance, the target vehicle speed range is further determined, which can accurately calculate the vehicle speed range corresponding to the engine under high fuel efficiency conditions, thus improving the accuracy of the calculation process.

[0071] In one implementation, the above method further includes:

[0072] Determine the target speed range of the engine, and based on the target speed range and the optimal performance curve, determine multiple target torque ranges; based on the engine's thermal efficiency, the target speed range, and the multiple target torque ranges, determine the minimum efficiency direct drive line.

[0073] The target speed range is the speed range from the minimum speed to the maximum speed of the engine; the target torque range is the torque range from the minimum torque to the maximum torque that the engine can output at any speed within the target speed range. The maximum torque of the engine at any speed within the target speed range is obtained based on the torque corresponding to that speed on the optimal performance curve.

[0074] In the embodiments of this application, the target speed range of the engine can be determined according to the universal characteristic diagram of the engine, which can be from 0 rpm to 1800 rpm; the target torque range that the engine can output can be determined according to the universal characteristic diagram and / or the optimal performance curve of the engine, which can be from 0 Nm to 200 Nm; and the minimum efficiency direct drive line is determined based on the target speed range, target torque range, optimal performance curve and thermal efficiency at the corresponding operating point of the engine of the hybrid vehicle.

[0075] In the above scheme, by combining the engine's optimal performance curve and thermal efficiency, and comprehensively considering the target speed range and target torque range, the minimum efficiency direct drive line is accurately determined, which can divide the engine's high-efficiency operating range, and is used to calculate the appropriate overall vehicle speed ratio to reduce fuel consumption.

[0076] In one implementation, the above method includes:

[0077] Based on the target speed range and multiple target torque ranges, multiple operating points are determined, where each operating point is obtained based on any speed within the target speed range and any torque within the target torque range corresponding to that speed. The first efficiency of each operating point in the first mode and the second efficiency in the second mode are calculated. Based on the first efficiency and the second efficiency of each operating point, the operating point where the first efficiency is less than or equal to the second efficiency is determined as the target operating point. Based on all the target operating points, the minimum efficiency line for direct drive is determined.

[0078] The first mode includes the engine direct drive mode, and the first efficiency is the thermal efficiency of the engine operating in the first mode; the second mode includes the parallel electric drive mode, which includes the parallel power generation mode and the pure electric drive mode, and the second efficiency is the thermal efficiency of the engine operating in the second mode.

[0079] In embodiments of this application, the efficiency boundary between engine direct drive mode and parallel electric drive mode can be determined according to a proportional operation algorithm, such as... Figure 2 As shown, Figure 2 This is a schematic diagram of the method for determining the minimum efficiency line of direct drive provided in this application embodiment. Assuming point A is an operating point of the engine in direct drive mode, the engine thermal efficiency η can be determined by querying the engine's universal characteristic diagram based on the engine speed and torque at point A. A Assume point B is an operating point in the parallel electric drive mode. The parallel electric drive mode includes a parallel generator mode and a pure electric drive mode. In the parallel generator mode, the engine drives the generator to produce electricity while simultaneously driving the vehicle directly. In the pure electric drive mode, the engine drives the generator to produce electricity, which is stored in the battery, and the electric motor draws energy from the battery to drive the vehicle. If point B is only an operating point in the parallel generator mode, the engine speed is the same as at point A, but the torque is the same as the torque at the current speed indicated by the OPT curve. The thermal efficiency η at point B can be determined by consulting the engine's universal characteristic curve. B热 If point B is only the operating point in pure electric drive mode, then in pure electric drive mode, we need to consider the engine's thermal efficiency, the mechanical transmission efficiency of the engine converting mechanical energy into electrical energy through the generator, the power generation efficiency of the generator transferring electrical energy to the battery, the battery's discharge efficiency, and the motor drive efficiency of the battery-driven motor. Therefore, the thermal efficiency at point B is determined to be η. B并 =η B热 @η机械传动 @η 发电 ·η 放电 ·η 发电 ·η 电机驱动 However, during actual vehicle operation, the vehicle switches between parallel power generation mode and pure electric drive mode. Therefore, the parallel electric drive mode at point B includes both parallel power generation mode and pure electric drive mode. Assuming that the proportion of parallel power generation mode in the parallel electric drive mode is 1 and the proportion of pure electric drive mode is K, then the overall efficiency at point B is:

[0080]

[0081] In practice, the torque of the engine in parallel power generation mode is generally greater than that at point A. Therefore, this application takes point A as the operating point with the minimum torque in parallel power generation mode and point B as the operating point with the maximum torque in pure electric drive mode. Thus, the ratio is determined accordingly. Among them, T A With T B These are the torque values ​​corresponding to points A and B, respectively.

[0082] Calculate the efficiency η of the engine in direct drive mode at different speeds and torques. A And the efficiency η of the parallel electric drive mode B总 For example, using 100 revolutions per minute (rpm) as a fixed value, we iterate through the efficiency η corresponding to different torques at 100 rpm. A With η B总 This process iterates through the entire engine speed range in this manner, covering all η values. A ≤η B总 The operating point is retained as the target operating point. Connecting all the target operating points into a line can determine the dividing line of engine thermal efficiency between engine direct drive mode and parallel electric drive mode on the universal characteristic diagram, that is, the lowest efficiency line of direct drive.

[0083] Optionally, in one implementation, all operating points are traversed, and all η values ​​are... A ≤η B总 The operating point is retained as the target operating point. Connecting all the target operating points with a line can determine the dividing line of engine thermal efficiency between engine direct drive mode and parallel electric drive mode on the universal characteristic diagram, that is, the minimum efficiency direct drive line. Based on the minimum efficiency direct drive line, combined with the economic speed range obtained based on the universal characteristic diagram of the engine, the target vehicle speed range can be determined. Based on the target vehicle speed range, the required vehicle speed range, and the economic speed range, the theoretical total speed ratio of the hybrid vehicle can be determined.

[0084] For example, the minimum engine speed can be 100 rpm, the maximum engine speed can be 1500 rpm, and the preset speed interval can be 10 rpm; starting from 100 rpm, the search first looks for η when the engine speed is 100 rpm and the torque is 10 Nm. A With η B总 If η A ≤η B总 Then retain this operating point (operating point with a speed of 100 rpm and a torque of 10 Nm) as the target operating point. If η A >η B总 Then, this operating point is not retained; next, η is calculated when the speed is 100 rpm and the torque is 20 Nm. A With η B总 If η A ≤η B总 Then retain this operating point (operating point with a speed of 100 rpm and a torque of 10 Nm), if η A >η B总 Then, this operating point is not retained; assuming the torque on the corresponding OPT line at engine speed of 100 rpm is 30 Nm, then the calculation is performed up to 100 rpm with a torque of 30 Nm; next, the calculation is performed when the engine speed is 110 rpm and the torque is 10 Nm. A With η B总 Similarly, the torque value is calculated from 10 Nm to the corresponding OPT line at an engine speed of 110 rpm; until the torque value at 1500 rpm and 1500 Nm on the corresponding OPT line. Based on all the retained operating points, a line can be drawn on the engine's universal characteristic diagram, which is the lowest efficiency direct drive line.

[0085] Optionally, in one implementation, at the same rotational speed, there exist multiple values ​​that satisfy η. A ≤η B总 If the operating point is such that the torque is at the maximum at that speed, then the target operating point is selected; or, η is selected. A With η B总 The operating point with the smallest difference is taken as the target operating point.

[0086] The above solution can accurately analyze and compare the efficiency of the engine operating points under different modes. Based on the relationship between the first efficiency and the second efficiency, the target operating points are reasonably selected, and the lowest efficiency direct drive line is determined for subsequent calculation of the appropriate overall vehicle speed ratio to reduce fuel consumption.

[0087] S130. Based on the required vehicle speed range, the theoretical total speed ratio is corrected to obtain the target total speed ratio of the hybrid vehicle in the highest gear.

[0088] In one implementation, the above method further includes:

[0089] Based on the theoretical total speed ratio and the engine's economic speed, the target vehicle speed range is determined, where the engine's economic speed includes the first target speed and the second target speed. Based on the target vehicle speed range and the required vehicle speed range, the theoretical total speed ratio is corrected to obtain the target total speed ratio when the gear is in the highest gear.

[0090] In the above scheme, the theoretical overall speed ratio and the engine's economic speed can be determined, thus defining the vehicle speed range corresponding to the engine's economic speed under that theoretical overall speed ratio. Based on the required vehicle speed range and the vehicle speed range corresponding to the economic speed, the theoretical overall speed ratio is corrected to ensure that the engine speed is within the economic speed range when the vehicle is traveling within the user's required speed range, thereby improving fuel efficiency. In one implementation, the above method includes:

[0091] If the target speed range matches the required speed range, the correction factor is set to 1. The theoretical total speed ratio is then corrected based on this correction factor to obtain the target total speed ratio of the hybrid vehicle in the highest gear. If the target speed range does not match the required speed range, the correction factor is set to the target difference between the second-highest gear and the highest gear. The theoretical total speed ratio is then corrected based on this correction factor to obtain the target total speed ratio of the hybrid vehicle in the highest gear.

[0092] In one embodiment, the target speed range matching the required speed range can mean that the target speed range includes the required speed range, that is, the required speed range is a subset of the target speed range.

[0093] For example, if the target speed range is 70km / h to 91km / h and the required speed range is 70km / h to 80km / h, then the target speed range matches the required speed range. In this case, the correction factor is set to 1. Assuming that the theoretical total speed ratio is 2.69, the theoretical total speed ratio is corrected based on the correction factor, and the target total speed ratio of the hybrid vehicle is determined to be 2.69.

[0094] For example, if the target speed range is 60km / h to 69km / h and the required speed range is 70km / h to 80km / h, then the target speed range does not match the required speed range. Assuming that the theoretical total speed ratio is 2.69, 2.69 is determined as the total speed ratio of the hybrid vehicle in the second highest gear. The correction factor is determined as the target gear difference. The theoretical total speed ratio is corrected according to the correction factor to obtain the target total speed ratio of the hybrid vehicle in the highest gear.

[0095] In one embodiment, the target speed range matching the required speed range can mean that the required speed range includes the target speed range, that is, the target speed range is a subset of the required speed range.

[0096] In one embodiment, the target speed range matching the required speed range can mean that the required speed range and the target speed range overlap.

[0097] In one embodiment, the target speed range and the required speed range can be matched if the error between the median speed of the required speed range and the median speed of the target speed range does not exceed a preset speed threshold. The preset speed threshold can be set differently by professional technicians according to specific circumstances. Preferably, in the embodiments of this application, the preset speed threshold can be 5 km / h.

[0098] For example, if the target speed range is 70km / h to 90km / h, the median speed of the target speed range is 80km / h, the required speed range is 70km / h to 80km / h, the median speed of the required speed range is 75km / h, and the error between the median speed of the target speed range and the median speed of the required speed range does not exceed 5km / h, then the target speed range and the required speed range are consistent. In this case, the correction factor is set to 1. Assuming that the theoretical total speed ratio is 2.69, the theoretical total speed ratio is corrected based on the correction factor, and the target total speed ratio of the hybrid vehicle is determined to be 2.69.

[0099] For example, if the target speed range is 80km / h to 90km / h, the median speed of the target speed range is 85km / h, the required speed range is 70km / h to 80km / h, and the median speed of the required speed range is 75km / h, and the error between the median speed of the target speed range and the median speed of the required speed range exceeds 5km / h, then the target speed range does not match the required speed range. Assuming that the theoretical total speed ratio is 2.69 at this time, 2.69 is determined as the total speed ratio of the hybrid vehicle in the second highest gear, and the correction coefficient is determined as the target grade difference. The theoretical total speed ratio is corrected according to the correction coefficient to obtain the target total speed ratio of the hybrid vehicle in the highest gear.

[0100] In the above scheme, if the target speed range matches the required speed range, that is, under the theoretical total speed ratio, the speed range corresponding to the engine's economic speed is close to the user's required speed range, and the current value of the theoretical total speed ratio can ensure that the engine speed is within the economic speed range when the vehicle is driving within the user's required speed range, the correction coefficient is set to 1. Based on the correction coefficient and the theoretical total speed ratio, the target total speed ratio of the hybrid vehicle in the highest gear is obtained. If the target speed range does not match the required speed range, then under the theoretical total speed ratio, the speed range corresponding to the engine's economic speed differs significantly from the user's required speed range. In this case, the correction coefficient is set to the target level difference. Based on the correction coefficient, the theoretical total speed ratio is corrected to obtain the target total speed ratio. By setting the level difference, the theoretical total speed ratio can be corrected so that when the hybrid vehicle is driving within the user's required speed range, the engine will operate in the most fuel-efficient mode.

[0101] In one implementation, the above method includes:

[0102] The minimum grade difference is determined based on the maximum value within the required vehicle speed range and the maximum value between the first and second target speeds; the maximum grade difference is determined based on the minimum value within the required vehicle speed range and the minimum value between the first and second target speeds; the grade difference range is determined based on the minimum and maximum grade differences; and the target grade difference is determined based on the grade difference range.

[0103] For example, if the target speed range does not match the required speed range, assuming the required speed range is 85km / h to 95km / h and the economic speed range is 1000rpm to 1300rpm, the theoretical total gear ratio of 2.96 is determined as the total gear ratio of the hybrid vehicle in the second-highest gear. Since the gear difference = total gear ratio in the second-highest gear / total gear ratio in the highest gear, the first gear difference can be determined based on the minimum value of the required speed range and the minimum value of the economic speed range: 2.69 × 85 / (0.377 × 100). 0×0.5)=1.21, the second level difference can be determined based on the maximum value of the required vehicle speed range and the maximum value of the economic speed range = 2.69×95 / (0.377×1300×0.5)=1.04. Based on these two level difference values, the level difference range is determined to be 1.04 to 1.21. The level difference value can be selected within the level difference range. For example, 1.20 can be selected as the level difference value. The total speed ratio of the hybrid vehicle in the highest gear = the total speed ratio in the second highest gear / level difference = 2.96 / 1.20=2.47.

[0104] It should be noted that in the calculation of the hybrid vehicle parameters provided in the above embodiments, the specific values ​​are expressed with two decimal places and rounding is used in the calculation. Professional technicians can make different settings according to specific circumstances. This is only an example and is not a specific limitation.

[0105] Optionally, in one implementation, the target total speed ratio can be determined directly based on the required vehicle speed range and the economic speed range, without needing to determine the target vehicle speed range based on the economic speed range. The speed ratio is determined based on whether the target vehicle speed range includes the required vehicle speed range. For example, the speed ratio can be determined based on the minimum value of the required vehicle speed range and the minimum value of the economic speed range = 0.377 × 1000 × 0.5 / 85 = 2.22. The second-level difference can be determined based on the maximum value of the required vehicle speed range and the maximum value of the economic speed range = 0.377 × 1300 × 0.5 / 95 = 2.58. Based on these two speed ratios, the target total speed ratio range is determined to be 2.22 to 2.58. The speed ratio value can be selected within the target total speed ratio range, for example, 2.50 can be selected as the target total speed ratio.

[0106] In the above scheme, if the target speed range does not match the required speed range, the appropriate range can be determined by determining the gear ratio based on the required speed range and the economic speed. Based on the gear ratio, the target total gear ratio can be further determined, so that when the hybrid vehicle is driving within the user's required speed range, the engine will operate in the most fuel-efficient way.

[0107] In one implementation, the above method further includes:

[0108] The final drive ratio of the hybrid vehicle's transmission is determined based on the target total gear ratio and the preset gear ratio of the highest gear.

[0109] Among them, the gear ratio is the speed ratio between the input shaft and the output shaft of the gear in the transmission; the final reduction ratio is the final reduction ratio from the transmission to the wheels, which represents the relationship between the speed output by the transmission and the speed of the wheels.

[0110] For example, the gear ratio of the highest gear can be 1.0, and the target total gear ratio of the vehicle in the highest gear is 2.50. There is a relationship between the final drive ratio, the gear ratio of the highest gear, and the target total gear ratio in the highest gear: target total gear ratio = final drive ratio × gear ratio of the highest gear. Based on the above relationship, the final drive ratio can be determined to be 2.50 / 1.0 = 2.50.

[0111] Optionally, in the above embodiments, the speed ratio of all gears can be determined based on a fixed gear difference and the highest gear ratio. Professional technicians can set different gear differences according to specific circumstances. This is only an example and is not a specific limitation.

[0112] In the above scheme, the final drive ratio of the hybrid vehicle is determined based on the preset highest gear ratio and the target total speed ratio. This allows for the setting of a reasonable final drive ratio, ensuring that the hybrid vehicle can output sufficient power to meet the user's required speed range under the corresponding target total speed ratio.

[0113] In the above embodiments, by obtaining the optimal performance curve of the hybrid vehicle's engine and the required speed range, the theoretical total speed ratio of the hybrid vehicle is determined based on the optimal performance curve, thus identifying a speed ratio that matches the engine's efficient operating state. Based on the required speed range, the theoretical total speed ratio is corrected to obtain the target total speed ratio of the hybrid vehicle. Since the optimal performance curve and the required speed range are used to determine the theoretical total speed ratio with the highest energy transfer efficiency for the hybrid vehicle under pure engine drive conditions, and the correction of the theoretical total speed ratio based on the required speed range ensures that the hybrid vehicle operates within the required speed range at the optimal speed ratio with the highest energy transfer efficiency, thereby improving the fuel efficiency of the hybrid vehicle.

[0114] The following is combined Figure 3 An example is provided to illustrate another method for determining hybrid vehicle parameters provided in the embodiments of this application.

[0115] Figure 3 This is a schematic flowchart illustrating another method for determining hybrid vehicle parameters provided in this application embodiment; as follows: Figure 3 As shown, method 300 includes S301 to S311, which are described in detail below.

[0116] S301. Based on the engine's OPT line, determine the minimum efficiency direct drive line; based on the engine's universal characteristic diagram, determine the economic speed range.

[0117] For example, such as Figure 2 As shown, assuming point A is an operating point in the engine's direct drive mode, the engine speed and torque at point A can be used to determine the engine's thermal efficiency η by consulting the engine's universal characteristic diagram. A Assume point B is an operating point in the parallel electric drive mode. The parallel electric drive mode includes a parallel generator mode and a pure electric drive mode. In the parallel generator mode, the engine drives the generator to produce electricity while simultaneously driving the vehicle directly. In the pure electric drive mode, the engine drives the generator to produce electricity, which is stored in the battery, and the electric motor draws energy from the battery to drive the vehicle. If point B is only an operating point in the parallel generator mode, the engine speed is the same as at point A, but the torque is the same as the torque at the current speed indicated by the OPT curve. The thermal efficiency η at point B can be determined by consulting the engine's universal characteristic curve. B热 If point B is only the operating point in pure electric drive mode, then in pure electric drive mode, we need to consider the engine's thermal efficiency, the mechanical transmission efficiency of the engine converting mechanical energy into electrical energy through the generator, the power generation efficiency of the generator transferring electrical energy to the battery, the battery's discharge efficiency, and the motor drive efficiency of the battery-driven motor. Therefore, the thermal efficiency at point B is determined to be η. B并 =η B热 ·η 机械传动 @η 发电 @η 放电 @η 发电 ·η 电机驱动 However, during actual vehicle operation, the vehicle switches between parallel power generation mode and pure electric drive mode. Therefore, the parallel electric drive mode at point B includes both parallel power generation mode and pure electric drive mode. Assuming that the proportion of parallel power generation mode in the parallel electric drive mode is 1 and the proportion of pure electric drive mode is K, then the overall efficiency at point B is:

[0118]

[0119] In practice, the torque of the engine in parallel power generation mode is generally greater than that at point A. Therefore, this application takes point A as the operating point with the minimum torque in parallel power generation mode and point B as the operating point with the maximum torque in pure electric drive mode. Thus, the ratio is determined accordingly. Among them, T A With T B Let A and B be the torque values ​​corresponding to points A and B, respectively. Calculate the efficiency η of the engine in direct drive mode at different speeds and torques. A And the efficiency η of the parallel electric drive mode B总 For example, using 100 revolutions per minute (rpm) as a fixed value, we iterate through the efficiency η corresponding to different torques at 100 rpm. A With η B总 This process iterates through the entire engine speed range in this manner, covering all η values. A ≤η B总 The operating point is retained as the target operating point. Connecting all the target operating points into a line can determine the dividing line of engine thermal efficiency between engine direct drive mode and parallel electric drive mode on the universal characteristic diagram, that is, the lowest efficiency line of direct drive.

[0120] Optionally, in one implementation, all operating points are traversed, and all η values ​​are... A ≤η B总 The operating point is retained as the target operating point. Connecting all the target operating points into a line can determine the dividing line of engine thermal efficiency between engine direct drive mode and parallel electric drive mode on the universal characteristic diagram, that is, the minimum efficiency direct drive line. Based on the minimum efficiency direct drive line, combined with the economic speed range obtained based on the universal characteristic diagram of the engine, the theoretical total speed ratio of the hybrid vehicle can be determined.

[0121] For example, the minimum engine speed can be 100 rpm, the maximum engine speed can be 1500 rpm, and the preset speed interval can be 10 rpm; starting from 100 rpm, the search first looks for η when the engine speed is 100 rpm and the torque is 10 Nm. A With η B总 If η A ≤η B总 Then retain this operating point (operating point with a speed of 100 rpm and a torque of 10 Nm) as the target operating point. If η A >η B总 Then, this operating point is not retained; next, η is calculated when the speed is 100 rpm and the torque is 20 Nm. A With η B总 If η A ≤η B总Then retain this operating point (operating point with a speed of 100 rpm and a torque of 10 Nm), if η A >η B总 Then, this operating point is not retained; assuming the torque on the corresponding OPT line at engine speed of 100 rpm is 30 Nm, then the calculation is performed up to 100 rpm with a torque of 30 Nm; next, the calculation is performed when the engine speed is 110 rpm and the torque is 10 Nm. A With η B总 Similarly, the torque value is calculated from 10 Nm to the corresponding OPT line at an engine speed of 110 rpm; until the torque value at 1500 rpm and 1500 Nm on the corresponding OPT line. Based on all the retained operating points, a line can be drawn on the engine's universal characteristic diagram, which is the lowest efficiency direct drive line.

[0122] Optionally, in one implementation, at the same rotational speed, there exist multiple values ​​that satisfy η. A ≤η B总 If the operating point is such that the torque is at the maximum at that speed, then the target operating point is selected; or, η is selected. A With η B总 The operating point with the smallest difference is taken as the target operating point.

[0123] In the embodiments of this application, the thermal efficiency boundary line between the engine direct drive mode and the parallel electric drive mode can be determined according to the above method, that is, the lowest efficiency line of direct drive; the economic speed range of the engine can be determined based on the universal characteristic diagram of the engine, which can be from 1000 rpm to 1300 rpm.

[0124] Optionally, the implementation of S301 can be found in [reference needed]. Figure 1 The implementation details in S120 are not repeated here.

[0125] S302. Based on the lowest efficiency direct drive line, determine the power P1 and P2 corresponding to the lowest and highest speeds in the economic speed range.

[0126] For example, the economic speed range can be from 1000 rpm to 1300 rpm. The speeds at the two ends of the economic speed range can be determined as the first target speed and the second target speed. For example, the minimum speed in the economic speed range can be determined as the first target speed, which is 1000 rpm. The maximum speed in the economic speed range can be determined as the second target speed, which is 1300 rpm. The power range can be determined based on the minimum efficiency direct drive line and the economic speed range. Based on the economic speed range and the minimum efficiency direct drive line, the first target power P1 corresponding to the first target speed and the second target power P2 corresponding to the second target speed can be determined. P1 to P2 is the target power range.

[0127] Optionally, the implementation of S302 can be found in [reference needed]. Figure 1 The implementation details in S120 are not repeated here.

[0128] S303. Based on P1, P2 and driving resistance, determine the vehicle speeds v1 and v2 corresponding to the lowest and highest speeds in the economic speed range.

[0129] For example, based on the target power range and driving resistance, the minimum vehicle speed v1 corresponding to 1000 rpm and the minimum vehicle speed v2 corresponding to 1300 rpm can be determined, where v1 to v2 is the target vehicle speed range.

[0130] Optionally, the implementation of S303 can be found in [reference needed]. Figure 1 The implementation details in S120 are not repeated here.

[0131] S304. Based on the vehicle speed formula, determine the speed ratios i1 and i2, and determine the smaller value of i1 and i2 as the theoretical total speed ratio.

[0132] Optionally, the implementation of S304 can be found in [reference needed]. Figure 1 The implementation details in S120 are not repeated here.

[0133] S305. Determine the corresponding target vehicle speed range based on the theoretical total speed ratio and the economic speed range.

[0134] Optionally, the implementation of S305 can be found in [reference needed]. Figure 1 The relevant description of the implementation method in S130 will not be repeated here.

[0135] S306. Determine whether the target speed range matches the required speed range; if yes, proceed to S307; if no, proceed to S308.

[0136] In the embodiments of this application, it is determined whether the target vehicle speed range matches the required vehicle speed range. If they match, it means that the theoretical total speed ratio can enable the engine to reach all the vehicle speed ranges required by the user at economic speed. In this case, the theoretical total speed ratio is determined as the target total speed ratio of the vehicle in the highest gear. The specific implementation method is shown in S307. If the target vehicle speed range does not match the required vehicle speed range, it means that the theoretical total speed ratio cannot enable the engine to reach all the vehicle speed ranges required by the user at economic speed. In this case, the theoretical total speed ratio is determined as the total speed ratio of the vehicle in the second highest gear. The specific implementation method is shown in S308.

[0137] Optionally, the implementation of S306 can be found in [reference needed]. Figure 1 The relevant description of the implementation method in S130 will not be repeated here.

[0138] S307. The theoretical total speed ratio is determined as the target total speed ratio of the vehicle when it is in the highest gear.

[0139] Optionally, the implementation of S307 can be found in [reference needed]. Figure 1 The relevant description of the implementation method in S130 will not be repeated here.

[0140] S308. The theoretical total speed ratio is determined as the total speed ratio of the vehicle in the second-highest gear.

[0141] Optionally, the implementation of S308 can be found in [reference needed]. Figure 1 The relevant description of the implementation method in S130 will not be repeated here.

[0142] S309. The grade difference range is determined based on the theoretical total speed ratio, the required vehicle speed range, and the economic speed range.

[0143] For example, the target speed range is 70km / h to 91km / h, the required speed range is 85km / h to 95km / h, and the economic speed range is 1000rpm to 1300rpm. The target speed range does not match the required speed range. The theoretical total gear ratio of 2.96 is determined as the total gear ratio of the vehicle in the second-highest gear. Since the gear difference = total gear ratio in the second-highest gear / total gear ratio in the highest gear, the first gear difference can be determined based on the minimum value of the required speed range and the minimum value of the economic speed range = 2.69×85 / (0.377×1000×0.5) = 1.21. The second gear difference can be determined based on the maximum value of the required speed range and the maximum value of the economic speed range = 2.69×95 / (0.377×1300×0.5) = 1.04. Based on these two gear difference values, the gear difference range is determined to be 1.04 to 1.21.

[0144] Optionally, the implementation of S309 can be found in [reference needed]. Figure 1 The relevant description of the implementation method in S130 will not be repeated here.

[0145] S310. Determine the grade difference within the grade difference range, and determine the target total speed ratio based on the grade difference.

[0146] For example, the increment range is 1.04 to 1.21. The increment value can be selected within the increment range. For example, 1.20 can be selected as the target increment. The target total speed ratio of the hybrid vehicle in the highest gear = the total speed ratio in the second highest gear / increment = 2.96 / 1.20 = 2.47.

[0147] Optionally, the implementation of S310 can be found in [reference needed]. Figure 1 The relevant description of the implementation method in S130 will not be repeated here.

[0148] S311. Determine the main reduction ratio based on the preset highest gear ratio and the target total speed ratio.

[0149] For example, the gear ratio of the highest gear can be 1.0, and the target total gear ratio of the vehicle in the highest gear is 2.50. There is a relationship between the final drive ratio, the gear ratio of the highest gear, and the target total gear ratio in the highest gear: target total gear ratio = final drive ratio × gear ratio of the highest gear. Based on the above relationship, the final drive ratio can be determined to be 2.50 / 1.0 = 2.50.

[0150] Optionally, the implementation of S311 can be found in [reference needed]. Figure 1 The relevant description of the implementation method in S130 will not be repeated here.

[0151] In the above embodiments, by obtaining the optimal performance curve of the hybrid vehicle's engine and the required speed range, the theoretical total speed ratio of the hybrid vehicle is determined based on the optimal performance curve, thus identifying a speed ratio that matches the engine's efficient operating state. Based on the required speed range, the theoretical total speed ratio is corrected to obtain the target total speed ratio of the hybrid vehicle. Since the optimal performance curve and the required speed range are used to determine the theoretical total speed ratio with the highest energy transfer efficiency for the hybrid vehicle under pure engine drive conditions, and the correction of the theoretical total speed ratio based on the required speed range ensures that the hybrid vehicle operates within the required speed range at the optimal speed ratio with the highest energy transfer efficiency, thereby improving the fuel efficiency of the hybrid vehicle.

[0152] The above text combined Figures 1 to 3 This application provides a detailed description of a method for determining parameters of a hybrid vehicle, as illustrated in its embodiments. The following will combine... Figure 4 The apparatus embodiments of this application are described in detail below. It should be understood that the apparatus in the embodiments of this application can perform the various methods described in the foregoing embodiments of this application, that is, the specific working processes of the various products described below can be referred to the corresponding processes in the foregoing method embodiments.

[0153] Figure 4This is a schematic diagram of a device for determining parameters of a hybrid vehicle provided in an embodiment of this application. The device 400 includes an acquisition module 410 and a processing module 420.

[0154] The acquisition module is used to acquire the optimal performance curve of the engine and the required vehicle speed range of the hybrid vehicle.

[0155] The processing module is used to determine the theoretical total speed ratio of the hybrid vehicle based on the optimal performance curve; and to correct the theoretical total speed ratio based on the required vehicle speed range to obtain the target total speed ratio of the hybrid vehicle in the highest gear.

[0156] Optionally, as one embodiment, the processing module 420 is specifically used for:

[0157] Based on the theoretical total speed ratio and the engine's economic speed, a target vehicle speed range is determined, wherein the engine's economic speed includes a first target speed and a second target speed; based on the target vehicle speed range and the required vehicle speed range, the theoretical total speed ratio is corrected to obtain the target total speed ratio of the hybrid vehicle in its highest gear.

[0158] Optionally, as one embodiment, the processing module 420 is specifically used for:

[0159] The economic speed of the engine is determined based on the engine's economic speed range, which includes a first target speed and a second target speed. Based on the optimal performance curve and the first target speed, a first economic vehicle speed is determined. Based on the first economic vehicle speed, a first gear ratio is determined. Based on the optimal performance curve and the second target speed, a second economic vehicle speed is determined. Based on the second economic vehicle speed, a second gear ratio is determined. The gear ratio with the smaller value between the first gear ratio and the second gear ratio is determined as the theoretical total gear ratio.

[0160] Optionally, as one embodiment, the processing module 420 is specifically used for:

[0161] If the target speed range matches the required speed range, the correction factor is set to 1. The theoretical total speed ratio is then corrected based on this correction factor to obtain the target total speed ratio of the hybrid vehicle in the highest gear. If the target speed range does not match the required speed range, the correction factor is set to the target difference between the second-highest gear and the highest gear. The theoretical total speed ratio is then corrected based on this correction factor to obtain the target total speed ratio of the hybrid vehicle in the highest gear.

[0162] Optionally, as one embodiment, the processing module 420 is specifically used for:

[0163] The minimum grade difference is determined based on the maximum value within the required vehicle speed range and the maximum value between the first and second target speeds; the maximum grade difference is determined based on the minimum value within the required vehicle speed range and the minimum value between the first and second target speeds; the grade difference range is determined based on the minimum and maximum grade differences; and the target grade difference is determined based on the grade difference range.

[0164] Optionally, as one embodiment, the processing module 420 is specifically used for:

[0165] The minimum efficiency direct drive line is determined based on the optimal performance curve and the engine's thermal efficiency. This minimum efficiency direct drive line is used to characterize the boundary between the engine's thermal efficiency in direct drive mode and parallel electric drive mode. Based on the minimum efficiency direct drive line and the first target speed, the first target power is determined. Based on the first target power and driving resistance, the first economic speed is determined. Based on the minimum efficiency direct drive line and the second target speed, the second target power is determined. Based on the second target power and driving resistance, the second economic speed is determined.

[0166] Optionally, as an embodiment, the processing module 420 is further configured to:

[0167] The final drive ratio of the hybrid vehicle's transmission is determined based on the target total gear ratio and the preset gear ratio of the highest gear.

[0168] Optionally, as an embodiment, the processing module 420 is further configured to:

[0169] The target speed range of the engine is determined, and multiple target torque ranges are determined based on the target speed range and the optimal performance curve. The target speed range is the speed range from the minimum speed to the maximum speed of the engine. The target torque range is the torque range from the minimum torque to the maximum torque that the engine can output at any speed within the target speed range. The maximum torque of the engine at any speed within the target speed range is obtained based on the torque corresponding to that speed on the optimal performance curve. Based on the engine's thermal efficiency, the target speed range, and the multiple target torque ranges, the efficiency direct drive minimum line is determined.

[0170] Optionally, as one embodiment, the processing module 420 is specifically used for:

[0171] Based on the target speed range and multiple target torque ranges, multiple operating points are determined. Each operating point is obtained based on any speed within the target speed range and any torque within the corresponding target torque range. The first efficiency in a first mode and the second efficiency in a second mode are calculated for each operating point. The first mode includes engine direct drive mode, and the first efficiency is the thermal efficiency of the engine operating in the first mode. The second mode includes parallel electric drive mode, which includes parallel power generation mode and pure electric drive mode, and the second efficiency is the thermal efficiency of the engine operating in the second mode. Based on the first and second efficiencies of each operating point, operating points where the first efficiency is less than or equal to the second efficiency are determined as target operating points. Based on all target operating points, the minimum efficiency line for direct drive is determined.

[0172] It should be noted that the aforementioned hybrid vehicle parameter determining device 400 is embodied in the form of a functional unit. The term "module" here can be implemented in software and / or hardware, without specific limitations.

[0173] For example, a "module" can be a software program, hardware circuitry, or a combination of both that implements the above-described functions. Hardware circuitry may include application-specific integrated circuits (ASICs), electronic circuitry, a processor (e.g., a shared processor, a proprietary processor, or a group processor) and memory for executing one or more software or firmware programs, integrated logic circuitry, and / or other suitable components that support the described functions.

[0174] Therefore, the units of the various examples described in the embodiments of this application can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0175] Through the above description of the embodiments, those skilled in the art will understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0176] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0177] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for determining parameters of a hybrid vehicle, characterized in that, The method includes: Obtain the optimal engine performance curve and required speed range for hybrid vehicles; Based on the optimal performance curve, the theoretical total speed ratio of the hybrid vehicle is determined; Based on the required vehicle speed range, the theoretical total speed ratio is corrected to obtain the target total speed ratio of the hybrid vehicle in the highest gear.

2. The method according to claim 1, characterized in that, The step of correcting the theoretical total gear ratio based on the required vehicle speed range to obtain the target total gear ratio of the hybrid vehicle in the highest gear includes: Based on the theoretical total speed ratio and the engine's economic speed, a target vehicle speed range is determined, wherein the engine's economic speed includes a first target speed and a second target speed; Based on the target vehicle speed range and the required vehicle speed range, the theoretical total speed ratio is corrected to obtain the target total speed ratio of the hybrid vehicle in the highest gear.

3. The method according to claim 1, characterized in that, Determining the theoretical total speed ratio of the hybrid vehicle based on the optimal performance curve includes: The economic speed of the engine is determined based on the economic speed range of the engine, wherein the economic speed of the engine includes a first target speed and a second target speed; Based on the optimal performance curve and the first target speed, determine the first economical vehicle speed. Based on the first economic speed, determine the first speed ratio; Based on the optimal performance curve and the second target speed, the second economic speed is determined; The second speed ratio is determined based on the second economic speed; The speed ratio that is smaller between the first speed ratio and the second speed ratio is determined as the theoretical total speed ratio.

4. The method according to claim 2, characterized in that, The step of correcting the theoretical total speed ratio based on the target vehicle speed range and the required vehicle speed range to obtain the target total speed ratio of the hybrid vehicle in the highest gear includes: If the target vehicle speed range matches the required vehicle speed range, the correction coefficient is set to 1, and the theoretical total speed ratio is corrected based on the correction coefficient to obtain the target total speed ratio of the hybrid vehicle in the highest gear. If the target speed range does not match the required speed range, the correction coefficient is determined as the target difference between the second-highest gear and the highest gear. Based on the correction coefficient, the theoretical total speed ratio is corrected to obtain the target total speed ratio of the hybrid vehicle in the highest gear.

5. The method according to claim 4, characterized in that, The target grade difference is obtained through the following steps: The minimum difference value is determined based on the maximum value in the required vehicle speed range and the maximum value between the first target speed and the second target speed; The maximum value of the grade difference is determined based on the minimum value in the required vehicle speed range and the minimum value between the first target speed and the second target speed; The range of grade differences is determined based on the minimum and maximum values ​​of the grade differences. The target grade difference is determined based on the grade difference range.

6. The method according to claim 3, characterized in that, The process of determining a first economical vehicle speed based on the optimal performance curve and the first target speed, and determining a second economical vehicle speed based on the optimal performance curve and the second target speed, includes: The lowest efficiency direct drive line is determined based on the optimal performance curve and the thermal efficiency of the engine. The lowest efficiency direct drive line is used to characterize the boundary line of engine thermal efficiency between engine direct drive mode and parallel electric drive mode. Based on the minimum efficiency direct drive line and the first target speed, determine the first target power; Based on the first target power and driving resistance, the first economic speed is determined; The second target power is determined based on the efficiency direct drive minimum line and the second target speed; The second economic speed is determined based on the second target power and driving resistance.

7. The method according to any one of claims 1 to 6, characterized in that, The method further includes: Based on the target total gear ratio and the preset gear ratio of the highest gear, the final drive ratio of the hybrid vehicle's transmission is determined.

8. The method according to claim 6, characterized in that, The determination of the minimum efficiency direct drive line based on the optimal performance curve and the engine's thermal efficiency includes: A target speed range for the engine is determined, and multiple target torque ranges are determined based on the target speed range and the optimal performance curve; wherein, the target speed range is the speed range from the minimum speed to the maximum speed of the engine; the target torque range is the torque range from the minimum torque to the maximum torque that the engine can output at any speed within the target speed range, and the maximum torque of the engine at any speed within the target speed range is obtained based on the torque corresponding to that speed on the optimal performance curve; Based on the engine's thermal efficiency, the target speed range, and multiple target torque ranges, the minimum efficiency direct drive line is determined.

9. The method according to claim 8, characterized in that, Determining the minimum efficiency direct drive line based on the engine's thermal efficiency, the target speed range, and multiple target torque ranges includes: Based on the target speed range and the multiple target torque ranges, the multiple operating points are determined, wherein the operating points are obtained based on any speed within the target speed range and any torque within the target torque range corresponding to that speed; Calculate the first efficiency in the first mode and the second efficiency in the second mode for each operating point; wherein, the first mode includes the engine direct drive mode, and the first efficiency is the thermal efficiency of the engine operating in the first mode; the second mode includes the parallel electric drive mode, which includes the parallel power generation mode and the pure electric drive mode, and the second efficiency is the thermal efficiency of the engine operating in the second mode. Based on the first efficiency and the second efficiency at each operating point, the operating point where the first efficiency is less than or equal to the second efficiency is determined as the target operating point. Based on all the target operating points, the minimum efficiency direct drive line is determined.

10. A device for determining parameters of a hybrid vehicle, characterized in that, The device includes: The acquisition module is used to obtain the optimal performance curve of the engine and the required vehicle speed range of the hybrid vehicle. The processing module is used to determine the target speed range of the hybrid vehicle based on the optimal performance curve; and to determine the target total speed ratio corresponding to the required speed range based on the target speed range and the required speed range.

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