A method for calculating energy consumption of urban electric bus line nodes based on OBD

Abstract

The present invention discloses a method for calculating energy consumption of nodes in urban electric bus lines based on an on-board automatic diagnostic system (OBD). First, the spatial coordinate information of each node is extracted, and the trajectory points in the actual operation of the electric vehicle are matched using acceleration and distance. Then, the energy consumption of the three states of approaching, stopping, and leaving within the node range and the total energy consumption at all nodes are calculated by voltage and current, providing data support for reducing the energy consumption and cost of electric buses and establishing a green and low-carbon public transportation system. The present invention can more accurately calculate the energy consumption of bus stops and intersection nodes in electric bus lines by combining the speed, acceleration, voltage, current and other data collected by OBD with the latitude and longitude of the trajectory points.

Description

Technical Field

[0001] The invention relates to a method for calculating energy consumption of nodes on a city electric bus line, and in particular to an OBD-based method for calculating energy consumption of nodes on a city electric bus line. Background Art

[0002] The transportation industry is one of the main energy-consuming industries in my country. In the face of energy and environmental issues, the development of new energy vehicles with low energy consumption and low emissions has become a social consensus. The country has introduced a series of policies to advocate the priority development of public transportation. New energy buses, especially electric buses, are also rapidly replacing fuel buses. In the future, my country will achieve full electrification of public vehicles.

[0003] Although electric buses account for a small proportion of the total number of motor vehicles, only 1.25% in 2020, their operating environment is special and quite different from that of ordinary electric vehicles. They have many stops and long operating time, especially at bus line nodes (including bus stops and intersections), where frequent acceleration and deceleration are required. The time within the node range accounts for about 50% of the total operating time of the line, which may make them contribute more to the energy consumption of the entire line. At present, on the one hand, the existing research on energy consumption or emissions at bus line nodes is concentrated in the field of fuel vehicles, while there are certain differences between the operation process of electric buses and fuel buses, such as faster acceleration, no need to shift gears, no idling state, etc.; on the other hand, the energy consumption calculation of electric buses at line nodes is relatively rough, and the precision needs to be further improved. Therefore, how to provide a more accurate method for calculating energy consumption at electric bus line nodes based on OBD (On-Board Diagnostic) data is a problem that technicians in this field need to solve urgently. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide an OBD-based method for calculating the energy consumption of urban electric bus line nodes, which can reasonably and accurately evaluate the energy consumption level of urban electric buses.

[0005] Technical solution: The method for calculating energy consumption at a node of an urban electric bus line of the present invention comprises the following steps:

[0006] S1, install an on-board diagnostic system on the electric bus, obtain various data of the electric bus operation through the data interface, and filter, clean and organize the acquired data to obtain the running time, speed, acceleration, longitude and latitude of the trajectory points, current and voltage of the electric bus;

[0007] S2, based on the constructed spatial point data, preliminary screening of trajectory points within the range of the electric bus line nodes, where the trajectory points are coordinate point information collected during the actual operation of the electric bus;

[0008] S3, identifying the trajectory point based on the acceleration and distance obtained in step S1;

[0009] S4, calculate the energy consumption at each node of the line.

[0010] The specific implementation steps of step S2 are as follows:

[0011] S21, abstract the bus stops and intersections into point data, extract the spatial longitude and latitude information of the nodes based on the network coordinate picking platform, complete the construction of spatial point data, and ensure that the coordinate system of the spatial longitude and latitude must match the coordinate system of the longitude and latitude of the trajectory point;

[0012] S22, based on the spatial location of bus stops and intersections, bus stops and intersections are divided into upstream, intermediate and downstream types:

[0013] If the bus stop is within the entrance road of the intersection, it is an upstream bus stop, and the corresponding intersection is an upstream intersection;

[0014] If the bus stop is within the exit lane of the intersection, it is a downstream bus stop, and the corresponding intersection is a downstream intersection;

[0015] The remaining bus stops and intersections are intermediate bus stops and intermediate intersections;

[0016] S23, determine the node setting distance according to the actual operation of the electric bus and the actual node spatial layout, and select the trajectory points within the node setting distance according to the spatial data; find the trajectory point with a speed of 0 within the node setting distance, and mark it as the stop point S.

[0017] In step S3, the identification of trajectory points includes the following types:

[0018] (3-1) Approach point recognition

[0019] For any stop point S, if it is located in the upstream or intermediate bus stop, intermediate or downstream intersection, the trajectory point from the stop point S forward is marked as the approach point A, which is the trajectory point of the entrance to the station or intersection. If the trajectory point acceleration a>-0.1m / s 2 , stop marking;

[0020] If the stop point S is located in the range of a downstream bus stop or an upstream intersection, the trajectory point is marked as approaching point A from the stop point S. If the distance L between a certain trajectory point and a spatial node is greater than or equal to half of the distance between the corresponding bus stop and the intersection, the marking is stopped;

[0021] (3-2) Departure point identification

[0022] For any stop point S, if it is located in the range of an intermediate or downstream bus stop, an intermediate or upstream intersection, the trajectory point from the stop point S is marked as the departure point D, which is the trajectory point of the exit road of the station or intersection. If the trajectory point acceleration a<0.1m / s 2 , stop marking;

[0023] If the stop point S is located in the upstream bus stop or downstream intersection, the trajectory point is marked as the entry point D from the stop point S. If the distance L between a trajectory point and the spatial node is greater than or equal to half of the distance between the corresponding bus stop and the intersection, the mark is stopped.

[0024] (3-3) Remaining trajectory point identification

[0025] If there is no stopping point S near the node, the front part of the trajectory point within the node setting distance is in a deceleration state, and the rear part is in an acceleration state, with a clear dividing point, then the approach point A and the departure point D are further determined based on the node setting distance according to the acceleration; otherwise, find the trajectory point N closest to the longitude and latitude of the spatial node, and take the trajectory point before point N within 1 / 2 of the node setting distance as the approach point A, and the trajectory point after point N within 1 / 2 of the node setting distance as the departure point D.

[0026] In step S4, the energy consumption calculation at each node of the line is implemented as follows:

[0027] S41, using the collected current and voltage to calculate the instantaneous energy consumption of each trajectory point during the actual operation of the electric vehicle, the formula is as follows:

[0028] E t =U t I t / 3600000

[0029] Where:

[0030] E t Indicates the instantaneous energy consumption at a certain trajectory point, in kWh;

[0031] U t Represents the instantaneous voltage at a certain trajectory point, in V;

[0032] I t Represents the instantaneous current at a certain trajectory point, in A;

[0033] S42, based on step S3 and step S41, count the energy consumption of each approach point, stop point and departure point within the route node range, and calculate the total energy consumption at each node, the formula is as follows:

[0034]

[0035] Where:

[0036] E represents the total energy consumption of a certain node range, in kWh;

[0037] n, m, and p are the numbers of approach points, stop points, and departure points within the route node range, respectively;

[0038] E ai , E sj , E dk Respectively represent the energy consumption of approach point, stop point and departure point within the line node range, in kWh.

[0039] Compared with the prior art, the present invention has the following significant effects: 1. The present invention can more accurately calculate the energy consumption at bus stops and intersections in electric bus lines by combining the speed, acceleration, voltage, current and other data collected by OBD with the longitude and latitude of the trajectory points; 2. The present invention provides an OBD-based method for calculating energy consumption at nodes of urban electric bus lines, which is mainly used for calculating and predicting energy consumption of urban electric buses, and provides data support for energy consumption control of urban electric buses. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a flow chart of the present invention;

[0041] Figure 2 (a) is a schematic diagram of an upstream bus station.

[0042] (b) is a schematic diagram of a downstream bus station.

[0043] (c) is a schematic diagram of an intermediate bus station;

[0044] Figure 3 This is a schematic diagram of the bus line node range. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0046] like Figure 1 As shown, the energy consumption calculation method at the node of the urban electric bus line of the present invention comprises the following steps:

[0047] Step 1: Electric bus data acquisition

[0048] An on-board diagnostic system is installed on the electric bus to obtain various types of data on the operation of the city's electric buses through the data interface. After acquisition, the data is screened, cleaned and sorted, invalid data such as data in the parking lot and outside the line are eliminated, and some missing data are filled in. After integration, the main data of the electric bus, such as running time, speed, acceleration, longitude and latitude of trajectory points, current, voltage, etc., are obtained.

[0049] Step 2: Preliminary screening of trajectory points within the line node range

[0050] Track points refer to the coordinate point information collected during the actual operation of electric buses. This process requires the use of external coordinate picking platforms and map platforms, such as Baidu coordinate picking system and Baidu map, etc. It mainly includes data organization and function realization. The realization process is as follows:

[0051] Step 21: Build spatial data

[0052] Bus line nodes include bus stops and intersections. Bus stops and intersections are abstracted as point data. The spatial longitude and latitude information of the nodes are extracted based on the network coordinate picking platform to ensure that the spatial longitude and latitude coordinate system of the nodes is consistent with the longitude and latitude coordinate system of the actual running trajectory of the electric bus.

[0053] Step 22: Determine the bus stop and intersection type

[0054] In some areas on bus routes, bus stops and intersections are intertwined and affect each other. It is necessary to distinguish the types of bus stops and intersections so as to provide a clear definition for each node range (such as Figure 3 As shown in the figure, the node range refers to the distance from when the bus decelerates to approach the node to when it accelerates to leave the node, i.e., the node setting distance). According to the spatial location of the bus stop and the intersection, the bus stop and the intersection are divided into upstream type, middle type and downstream type.

[0055] In the present invention, if Figure 2 As shown in (a), if the bus stop is within the entrance road (100m before the intersection), it is an upstream bus stop, and the corresponding intersection is an upstream intersection; Figure 2 As shown in (b), if the bus stop is in the exit lane (100m after the intersection), it is a downstream bus stop, and the corresponding intersection is a downstream intersection; Figure 2 As shown in (c), the remaining bus stops or intersections are intermediate bus stops and intermediate intersections. The types of bus stops and intersections on the up and down routes of electric buses are determined based on the network map platform.

[0056] Step 23: Preliminary identification and screening of trajectory points

[0057] According to the "Design Specifications for Urban Road Public Transport Stations, Yards and Plants" and the actual line operation, the node distance between the bus station and the intersection is set to 100m (i.e., including 50 meters before and after the node). First, the trajectory points within 50m before and after the node are selected based on the spatial data; secondly, it is determined whether there is a trajectory point with a speed of 0 within the set distance of each node. If the speed v=0, it is marked as the stop point S.

[0058] Step 3: Accurately identify trajectory points based on acceleration and distance

[0059] The trajectory points within the range of each line node include approach points and departure points, and the stop point is determined according to the actual situation (not every node has a "stop point". For example, at a bus stop, the driver first slows down and finds that no one is waiting for the bus or getting off. Then, before the speed drops to 0, he accelerates and leaves. Or at an intersection, he may pass directly when the green light is on. In this case, there is no stop point at this line node). According to the actual operation of the electric bus, the acceleration and deceleration state standards are determined. If the acceleration is greater than 0.1m / s 2 , then the vehicle is in acceleration state. If the acceleration is less than -0.1m / s 2 , it is in deceleration state. Figure 3 As shown, the identification types are as follows:

[0060] (3-1) Approach point recognition

[0061] For any stop point S, match the specific type of the node where it is located. If the range of S is an upstream or intermediate bus stop, an intermediate or downstream intersection, mark the trajectory point from the stop point S forward as the approach point A. If the trajectory point acceleration a>-0.1m / s 2 , stop mark; if the stop point S is located in the range of a downstream bus stop or an upstream intersection, mark the trajectory point from the stop point S forward as a close point A. If the distance L between a trajectory point and a node is greater than or equal to half of the distance between the corresponding bus stop and the intersection, stop mark.

[0062] (3-2) Departure point identification

[0063] For any stop point S, match the specific type of the node where it is located. If the range is an intermediate or downstream bus stop, an intermediate or upstream intersection, mark the trajectory point from the stop point S as the departure point D. If the trajectory point acceleration a is less than 0.1m / s 2 , stop mark; if the stop point S is located in the upstream bus stop or downstream intersection, mark the trajectory point from the stop point S as the entry point D. If the distance L between a trajectory point and the node is greater than or equal to half of the distance between the corresponding bus stop and the intersection, stop mark.

[0064] (3-3) Remaining trajectory point identification

[0065] For the trajectory points within the remaining node range, for example, an electric bus slows down when encountering a green light at a certain intersection or slows down to 13 km / h at a certain bus stop before accelerating to leave, if there is no stop point S near the node, and if there is a clear distinction between deceleration and acceleration (that is, the front part of the trajectory points within the node range is in a deceleration state, and the rear part is in an acceleration state, with a clear dividing point), then on the basis of the node set distance range of 100m, the approach point A and the departure point D are further marked according to the acceleration. At this time, the approach distance may be more than or less than 50m; otherwise, find the trajectory point N closest to the node spatial longitude and latitude. Within the range of 100m, the trajectory point before point N is taken as the approach point A, and the trajectory point after point N is taken as the departure point D.

[0066] Step 4: Calculation of energy consumption at nodes of electric bus lines

[0067] (4-1) Calculate instantaneous energy consumption

[0068] The collected current and voltage are used to calculate the second-by-second energy consumption of the electric bus at the actual running trajectory point within the node range. The calculation formula is as follows:

[0069] E t =U t I t / 3600000 (1)

[0070] In formula (1):

[0071] E t Indicates the instantaneous energy consumption at a certain trajectory point, in kWh;

[0072] U t Represents the instantaneous voltage at a certain trajectory point, in V;

[0073] I t It represents the instantaneous current at a certain trajectory point, in A.

[0074] (4-2) Calculate the total energy consumption of the node

[0075] The energy consumption of approach points, stop points and departure points within the node range is counted, and the energy consumption at the line node is estimated using the following formula:

[0076]

[0077] Where:

[0078] E represents the total energy consumption of a certain node range, in kWh;

[0079] n, m, and p are the numbers of approach points, stop points, and departure points within the route node range, respectively;

[0080] E ai , Esj , E dk It indicates the energy consumption of approach point, stop point and departure point within each line node, in kWh.

[0081] In order to facilitate the understanding and application of the present invention, the above method is used in combination with the embodiment to illustrate as follows:

[0082] In this embodiment, the operation data of the electric bus is provided by a bus company in Nanjing. This example extracts the data of a certain up route of bus No. 121 on April 22, 2021. The number of nodes of each type is shown in Table 1.

[0083] Table 1 Number of nodes of various types on the line

[0084]

[0085] Through calculation, the total energy consumption of bus stations is 2.91kWh, the total energy consumption of intersections is 3.36kWh, and the energy consumption at all line nodes is 6.27kWh, accounting for 51.5% of the total energy consumption of the line. The total energy consumption of approaching state within the node range is -2.70kWh, and negative values ​​indicate energy recovery. The total energy consumption of stopping state is 0.39kWh, and the total energy consumption of leaving state is 8.59kWh.

[0086] It can be seen from the above embodiments that the present invention can accurately calculate the energy consumption at the nodes of the electric bus line.

[0087] The embodiments in this specification focus on the differences from other embodiments, and the similar or identical parts between the embodiments can be referred to each other. For the operation of the embodiments in the present invention, since they correspond to the methods disclosed in the embodiments, the description is simpler, and the relevant parts can be referred to the method part description.

[0088] The above description is only a preferred embodiment of the present invention, and the present invention will not be limited to the embodiments shown herein. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for calculating energy consumption at nodes of urban electric bus lines based on OBD, characterized in that: The steps include: S1, install an on-board diagnostic system on the electric bus, obtain various data of the electric bus operation through the data interface, and filter, clean and organize the acquired data to obtain the running time, speed, acceleration, longitude and latitude of the trajectory points, current and voltage of the electric bus; S2, based on the constructed spatial point data, preliminary screening of trajectory points within the range of the electric bus line nodes, where the trajectory points are coordinate point information collected during the actual operation of the electric bus; S3, identifying the trajectory point based on the acceleration and distance obtained in step S1; S4, calculates the energy consumption at each node of the line, and the implementation process is as follows: S41, using the collected current and voltage to calculate the instantaneous energy consumption of each trajectory point during the actual operation of the electric vehicle, the formula is as follows: E t =U t I t / 3600000 Where: E t Indicates the instantaneous energy consumption at a certain trajectory point, in kWh; U t Represents the instantaneous voltage at a certain trajectory point, in V; I t Represents the instantaneous current at a certain trajectory point, in A; S42, based on step S3 and step S41, count the energy consumption of each approach point, stop point and departure point within the route node range, and calculate the total energy consumption at each node, the formula is as follows: Where: E represents the total energy consumption of a certain node range, in kWh; n, m, and p are the numbers of approach points, stop points, and departure points within the route node range, respectively; E ai , E sj , E dk Respectively represent the energy consumption of approach point, stop point and departure point within the line node range, in kWh.

2. The method for calculating energy consumption at nodes of urban electric bus lines based on OBD according to claim 1 is characterized in that: The specific implementation steps of step S2 are as follows: S21, abstract the bus stops and intersections into point data, extract the spatial longitude and latitude information of the nodes based on the network coordinate picking platform, complete the construction of spatial point data, and ensure that the coordinate system of the spatial longitude and latitude must match the coordinate system of the longitude and latitude of the trajectory point; S22, based on the spatial location of bus stops and intersections, bus stops and intersections are divided into upstream, intermediate and downstream types: If the bus stop is within the entrance road of the intersection, it is an upstream bus stop, and the corresponding intersection is an upstream intersection; If the bus stop is within the exit lane of the intersection, it is a downstream bus stop, and the corresponding intersection is a downstream intersection; The remaining bus stops and intersections are intermediate bus stops and intermediate intersections; S23, determine the node setting distance according to the actual operation of the electric bus and the actual node spatial layout, and select the trajectory points within the node setting distance according to the spatial data; find the trajectory point with a speed of 0 within the node setting distance, and mark it as the stop point S.

3. The method for calculating energy consumption at nodes of urban electric bus lines based on OBD according to claim 1 is characterized in that: In step S3, the identification of trajectory points includes the following types: (3-1) Approach point recognition For any stop point S, if it is located in the upstream or intermediate bus stop, intermediate or downstream intersection, the trajectory point from the stop point S forward is marked as the approach point A, which is the trajectory point of the entrance to the station or intersection. If the trajectory point acceleration a>-0.1m / s 2 , stop marking; If the stop point S is located in the range of a downstream bus stop or an upstream intersection, the trajectory point is marked as approaching point A from the stop point S. If the distance L between a certain trajectory point and a spatial node is greater than or equal to half of the distance between the corresponding bus stop and the intersection, the marking is stopped; (3-2) Departure point identification For any stop point S, if it is located in the range of an intermediate or downstream bus stop, an intermediate or upstream intersection, the trajectory point from the stop point S is marked as the departure point D, which is the trajectory point of the exit road of the station or intersection. If the trajectory point acceleration a<0.1m / s 2 , stop marking; If the stop point S is located in the upstream bus stop or downstream intersection, the trajectory points are marked as the entry point D from the stop point S. If the distance L between a certain trajectory point and the spatial node is greater than or equal to half of the distance between the corresponding bus stop and the intersection, the mark is stopped; (3-3) Remaining trajectory point identification If there is no stopping point S near the node, the front part of the trajectory point within the node setting distance is in a deceleration state, and the rear part is in an acceleration state, with a clear dividing point, then the approach point A and the departure point D are further determined based on the node setting distance according to the acceleration; otherwise, find the trajectory point N closest to the longitude and latitude of the spatial node, and take the trajectory point before point N within 1 / 2 of the node setting distance as the approach point A, and the trajectory point after point N within 1 / 2 of the node setting distance as the departure point D.

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