A method for judging the vehicle load state based on the energy consumption in the starting condition

Abstract

The present invention relates to a method for judging the vehicle load state based on the energy consumption in the starting condition, including drawing the acceleration time contour curves based on the acceleration cut-off speed and the energy consumption in the starting condition under different load states; under the condition of the same acceleration time, comparing the acceleration cut-off speed and the energy consumption signals in the starting condition of different load states, and fitting the change relationship γ curve group of the energy consumption in the starting condition and the acceleration cut-off speed; according to the γ curve group, establishing an m×n-dimensional matrix for judging the energy consumption in the starting condition under different load states with respect to the acceleration cut-off speed and the acceleration time, comparing the actual energy consumption in the actual starting stage of the vehicle with the statistical energy consumption in the starting condition corresponding to the working condition in the m×n-dimensional matrix, and determining the load state of the vehicle according to the comparison result. The present invention provides accurate input for the vehicle control system and the active safety control system, improves the vehicle control accuracy, and ensures the driving safety of the vehicle.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle control, and particularly relates to a method for judging the vehicle load state based on the energy consumption in the starting condition. Background Art

[0002] Electric vehicles have a series of advantages such as energy conservation, environmental protection, low comprehensive use cost, and good driving quality, and their popularity is increasing. However, the pure electric vehicle has a short cruising range and a slow energy replenishment speed, resulting in range anxiety for users and restricting its popularization. To solve this problem, on the one hand, it is necessary to develop high-energy-density batteries and their corresponding fast charging technologies. On the other hand, providing an accurate cruising range estimation result helps users plan their trips, improves the user experience of electric vehicle users, and alleviates anxiety. Therefore, the research on the accuracy of cruising range estimation has become a key point in the development of electric vehicles. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for judging the vehicle load state based on the energy consumption in the starting condition, which can quickly judge the load state by using the energy conservation principle according to the vehicle power parameters obtained during the vehicle starting and accelerating process, so as to solve the problem of low accuracy of the vehicle control technology caused by load changes.

[0004] Specifically, the present invention provides a method for judging the vehicle load state based on the energy consumption in the starting condition, including:

[0005] Drawing acceleration time contour curves based on the acceleration cut-off speed and the starting condition energy consumption under different load states;

[0006] Comparing the change characteristics of the starting condition energy consumption and the acceleration cut-off speed of the vehicle under different load states and different acceleration times. Under the condition of the same acceleration time, comparing the acceleration cut-off speed and the starting condition energy consumption signals of different load states, fitting the change relationship γ curve group of the starting condition energy consumption and the acceleration cut-off speed, and dividing different vehicle load intervals;

[0007] Setting the acceleration cut-off speed as an m-dimensional vector and the acceleration time as an n-dimensional vector, and establishing an m×n-dimensional matrix for judging the starting condition energy consumption under different load states with respect to the acceleration cut-off speed and the acceleration time according to the γ curve group;

[0008] Comparing the actual starting condition energy consumption in the actual starting stage of the vehicle with the statistical starting condition energy consumption of the corresponding condition in the m×n-dimensional matrix, and determining the load state of the vehicle according to the comparison result.

[0009] As a further description of the present invention, the drawing of the acceleration time contour curves based on the acceleration cut-off speed and the starting condition energy consumption under different load states specifically includes:

[0010] Conduct vehicle tests under different load conditions for a specific vehicle model and record the test data;

[0011] Extract the power battery bus voltage, power battery bus current, starting acceleration time, and vehicle speed signal during the starting acceleration process of the vehicle from a stationary state, and calculate the energy consumption under the starting condition. Among them, the moment when the accelerator pedal opening signal drops to 0 is used as the cut-off moment of the starting condition;

[0012] Record the acceleration time and the energy consumption under the starting condition corresponding to different acceleration cut-off vehicle speeds; compare the data of the three characteristic variables under different load conditions, and draw the acceleration time contour curve based on the acceleration cut-off vehicle speed and the energy consumption under the starting condition under different load conditions.

[0013] As a further description of the present invention, the calculation formula for the energy consumption under the starting condition is as follows:

[0014]

[0015] In formula (1), E is the energy consumption under the starting condition, with the unit of kw.s; U is the power battery bus voltage, with the unit of V; I is the power battery bus current, with the unit of A; t 0 is the starting moment of the starting condition, corresponding to the moment when the accelerator pedal opening is first greater than 0, with the unit of s; t 1 is the ending moment of the starting condition, corresponding to the moment when the accelerator pedal opening becomes 0, with the unit of s.

[0016] As a further description of the present invention, the determination of the load condition of the vehicle according to the comparison result includes:

[0017] If the energy consumption under the starting condition corresponding to the m×n-dimensional matrix > the actual energy consumption under the starting condition, then the vehicle belongs to the state with a smaller load distinguished by the γ curve group;

[0018] If the energy consumption under the starting condition corresponding to the m×n-dimensional matrix < the actual energy consumption under the starting condition, then the vehicle belongs to the state with a larger load distinguished by the γ curve group.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] By combining the analysis conclusion of the vehicle starting state data and based on the variation laws of the three characteristic parameters of the starting acceleration time T, the vehicle speed V_end, and the energy consumption E under the starting condition, the present invention can obtain the current vehicle load state, provide accurate input for the vehicle control system and the active safety control system, improve the vehicle control accuracy, and ensure the driving safety of the vehicle. Description of the Drawings

[0021] Figure 1 This is the implementation flowchart of the vehicle load state judgment method based on the energy consumption in the starting condition provided by the embodiment of the present invention;

[0022] Figure 2 It is the acceleration time contour curve based on the acceleration cut-off speed V_end and the starting condition energy consumption E under different load states. Detailed implementation manners

[0023] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] The technical solutions of the present invention will be explained below with reference to specific embodiments.

[0026] As Figure 1 shown, it is the implementation process of the vehicle load state judgment method based on the starting condition energy consumption provided in an embodiment of the present invention. The method includes:

[0027] Step 101: Draw the acceleration time contour curve based on the acceleration cut-off speed and the starting condition energy consumption under different load states.

[0028] The above step 101 is the process of statistical analysis of the vehicle starting condition data, that is, the drawing of the acceleration time contour curve based on the acceleration cut-off speed and the starting condition energy consumption under different load states, which specifically includes:

[0029] Carry out a vehicle test with different load states for a specific vehicle model and record the test data. Extract the power battery bus voltage U, the power battery bus current I, the starting acceleration time T and the vehicle speed V_end signal during the starting acceleration process of the vehicle from the stationary state. Calculate the starting condition energy consumption E according to formula (1), and the moment when the acceleration pedal opening signal drops to 0 is used as the starting condition cut-off moment.

[0030]

[0031] In formula (1), E is the energy consumption at the starting condition, with the unit of kw.s; U is the bus voltage of the power battery, with the unit of V; I is the bus current of the power battery, with the unit of A; t 0 is the starting moment of the starting condition, corresponding to the moment when the accelerator pedal opening is greater than 0 for the first time, with the unit of s; t 1 is the ending moment of the starting condition, corresponding to the moment when the accelerator pedal opening becomes 0, with the unit of s.

[0032] Record the acceleration time T and the starting condition energy consumption E corresponding to different acceleration cut-off speeds V_end. Compare the data of the three characteristic variables under different load states, and draw the acceleration time contour curves based on the acceleration cut-off speed and the starting condition energy consumption E under different load states, as Figure 2 shown.

[0033] Step 102: Compare the change characteristics of the starting condition energy consumption and the acceleration cut-off speed of the vehicle under different load states and different acceleration times. Under the condition of the same acceleration time, compare the acceleration cut-off speed and the starting condition energy consumption signals of different load states, fit the change relationship γ curve group of the starting condition energy consumption and the acceleration cut-off speed, and divide different vehicle load intervals.

[0034] The above step 102 is the fitting of the relationship characteristic γ curve group of the starting condition energy consumption E and the acceleration cut-off speed V_end: that is, compare the change characteristics of the starting condition energy consumption and the acceleration cut-off speed of the vehicle under different load states and different acceleration times. Under the condition of the same acceleration time T, compare the acceleration cut-off speed V_end and the starting condition energy consumption E signals of different load states, fit the change relationship γ curve group of the starting condition energy consumption and the acceleration cut-off speed, and divide different vehicle load intervals.

[0035] Step 103: Set the acceleration cut-off speed as an m-dimensional vector and the acceleration time as an n-dimensional vector. According to the γ curve group, establish an m×n-dimensional matrix for judging the starting condition energy consumption under different load states with respect to the acceleration cut-off speed and the acceleration time.

[0036] The above step 103 is the definition of the characteristic variable m×n-dimensional matrix: Set the acceleration cut-off speed V_end and the acceleration time T as m-dimensional and n-dimensional vectors at a certain step length. The change range and change interval need to be determined according to the data quality. Establish an m×n-dimensional matrix for judging the starting condition energy consumption E under different load states with respect to the acceleration cut-off speed V_end and the acceleration time T according to the γ curve group obtained in step 102.

[0037] Step 104: Compare the actual starting condition energy consumption in the actual starting stage of the vehicle with the statistical starting condition energy consumption of the corresponding condition in the m×n-dimensional matrix, and determine the load state of the vehicle according to the comparison result.

[0038] The above-mentioned step 104 is a vehicle load state judgment process: that is, the actual starting condition energy consumption E_act is calculated based on the actual power battery bus voltage and current signals during the vehicle starting stage, and is compared with the statistical starting condition energy consumption E of the corresponding condition in the m×n-dimensional matrix of characteristic variables. The load state of the vehicle is determined according to the comparison result.

[0039] If the starting condition energy consumption E corresponding to the matrix > the actual starting condition energy consumption E_act, the vehicle belongs to the state with a smaller load distinguished by this γ curve; if the starting condition energy consumption E corresponding to the matrix < the actual starting condition energy consumption E_act, the vehicle belongs to the state with a larger load distinguished by this γ curve. As Figure 2 shown, at the acceleration vehicle speed T = 5s, if the acceleration cut-off vehicle speed V_end is 10 km / h, by querying the m×n-dimensional matrix of the acceleration cut-off vehicle speed V_end and the acceleration time T, it can be known that the starting condition energy consumption E of the ordinates of two points A and B corresponding to the cut-off vehicle speed 12 km / h on the γ curve group A and E B . Two γ curves are used to distinguish the load states of the whole vehicle of 2T / 4T / 6T. If the measured pedal change rate E > E A , it is determined that the load state of the vehicle is 6T; if the measured pedal change rate E B < E < E A , it is determined that the load state of the vehicle is 4T; if the measured pedal change rate E < E B , it is determined that the load state of the vehicle is 2T.

[0040] The embodiment of the present invention combines the data analysis conclusion of the vehicle starting state. According to the variation laws of three characteristic parameters: the starting acceleration time T, the vehicle speed V_end, and the starting condition energy consumption E, the current vehicle load state can be obtained, providing accurate input for the vehicle control system and the active safety control system, improving the vehicle control accuracy, and ensuring the driving safety of the vehicle.

[0041] The above-given embodiments are preferred examples for implementing the present invention. The present invention is not limited to the above embodiments. Any non-essential addition or replacement made by those skilled in the art according to the technical features of the technical solution of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for judging the vehicle load state based on the energy consumption in the starting condition, characterized in that, it includes: Drawing the acceleration time contour curves based on the acceleration cut-off speed and the starting condition energy consumption under different load states; Comparing the variation characteristics of the starting condition energy consumption and the acceleration cut-off speed of the vehicle under different load states and different acceleration times. Under the condition of the same acceleration time, comparing the acceleration cut-off speed and the starting condition energy consumption signals of different load states, fitting the variation relationship γ curve group of the starting condition energy consumption and the acceleration cut-off speed, and dividing different vehicle load intervals; Setting the acceleration cut-off speed as an m-dimensional vector and the acceleration time as an n-dimensional vector, and establishing an m×n-dimensional matrix for judging the starting condition energy consumption based on the acceleration cut-off speed and the acceleration time under different load states according to the γ curve group; Comparing the actual starting condition energy consumption in the actual starting stage of the vehicle with the statistical starting condition energy consumption of the corresponding working condition in the m×n-dimensional matrix, and determining the load state of the vehicle according to the comparison result.

2. The method for judging the vehicle load state based on the starting condition energy consumption according to claim 1, characterized in that, The drawing of the acceleration time contour curves based on the acceleration cut-off speed and the starting condition energy consumption under different load states specifically includes: Carrying out a vehicle test with different load states for a specific vehicle model and recording the test data; Extracting the power battery bus voltage, power battery bus current, starting acceleration time and vehicle speed signals during the starting acceleration process of the vehicle from the stationary state, and calculating the starting condition energy consumption, where the moment when the acceleration pedal opening signal drops to 0 is used as the starting condition cut-off moment; Recording the acceleration time and the starting condition energy consumption corresponding to different acceleration cut-off speeds; comparing the data of the three characteristic variables under different load states, and drawing the acceleration time contour curves based on the acceleration cut-off speed and the starting condition energy consumption under different load states.

3. The method for judging the vehicle load state based on the starting condition energy consumption according to claim 2, characterized in that, The calculation formula of the starting condition energy consumption is as follows: In formula (1), E is the starting condition energy consumption, with the unit of kw.s; U is the power battery bus voltage, with the unit of V; I is the power battery bus current, with the unit of A; t 0 is the starting moment of the starting condition, corresponding to the moment when the accelerator pedal opening is greater than 0 for the first time, with the unit of s; t 1 is the end moment of the starting condition, corresponding to the moment when the accelerator pedal opening becomes 0, with the unit of s.

4. The method for judging the vehicle load state based on the starting condition energy consumption according to claim 1, characterized in that, The determination of the vehicle load state according to the comparison result includes: If the starting condition energy consumption corresponding to the m×n-dimensional matrix > the actual starting condition energy consumption, then the vehicle belongs to the state with a smaller load distinguished by the γ curve group; If the starting condition energy consumption corresponding to the m×n-dimensional matrix < the actual starting condition energy consumption, then the vehicle belongs to the state with a larger load distinguished by the γ curve group.

Images