A brake air pipeline control method for pure electric vehicles

Abstract

The present invention relates to the technical field of electric vehicle braking, and discloses a pure electric vehicle brake air pipeline control method, comprising the following steps: Step 1: obtaining the current humidity value H, the current vehicle air pressure value P and the air consumption level information of the road condition ahead in the brake air pipeline of the target vehicle; Step 2: comparing the size relationship between the current humidity value H and the set humidity value h: if H≥h, then control the air compressor to enter the high speed working mode; if H<h, then enter step 3; Step 3: based on the air consumption level information of the road condition ahead, compare the size relationship between the current vehicle air pressure value P and the first air pressure threshold value P1 and the second air pressure threshold value P2, and then control the air compressor to enter different working modes. By controlling the air compressor to be in different working modes under different circumstances, the energy consumption and the noise of the whole vehicle during operation are effectively reduced, the riding comfort is improved, and the moisture in the brake air pipeline can be removed in time to prevent the pipeline and brake components from being damaged.

Description

Technical Field

[0001] The invention relates to the technical field of electric vehicle braking, and in particular to a method for controlling a brake air pipeline of a pure electric vehicle. Background Art

[0002] As an important component of the vehicle, the electric air compressor system (electric air compressor system for short) is used to provide air source for the vehicle's pneumatic brake system and other auxiliary systems that require air source. At present, pure electric vehicles generally use pneumatic brake system and pneumatic door control system. Therefore, the electric air compressor system is one of the indispensable key systems in pure electric vehicles.

[0003] A pure electric vehicle is a vehicle that is completely driven by an electric motor, and the driving power is completely derived from the on-board rechargeable energy storage system (REESS). In recent years, pure electric vehicles have developed rapidly. Among them, the braking system is one of the important components of the vehicle and is closely related to driving safety. The brake air line is an important component of the braking system.

[0004] At present, the air pressure of the brake air pipeline is mainly achieved by controlling and adjusting the air compressor. The existing air compressor control strategy of pure electric vehicles still follows the control method of traditional fuel vehicles. The control strategy adopts a high speed start when the vehicle air pressure value is lower than the starting threshold and shuts down when the stop pressure threshold is reached. This control method has the problem of long working time and high energy consumption of the air compressor. Compared with traditional fuel vehicles, for pure electric vehicles, due to its relatively quiet operation characteristics, the above air compressor control method has the problem of high noise during vehicle operation. Generally, the working noise of a piston air compressor can reach 80~85dB, which has a significant impact on the riding comfort of pure electric vehicles. Summary of the invention

[0005] The technical problem solved by the present invention is: how to prevent the air compressor of a pure electric vehicle from working too long, consuming too much energy, and making too much noise, which seriously affects the riding comfort.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A method for controlling a brake air pipeline of a pure electric vehicle comprises the following specific steps: Step 1: Obtain the current humidity value H in the brake air pipeline of the target vehicle, the air usage level information of the road ahead, and the current vehicle air pressure value P of the target vehicle; the air usage level information of the road ahead is obtained through prediction by the E-control big data platform, and the air usage level information of the road ahead is divided into three levels, of which the first level is the highest level; Step 2: Compare the current humidity value H in the brake air pipeline with the set humidity value h: If H≥h, the air compressor is controlled to enter high speed working mode; If H<h, go to step 3; Step 3: Compare the current vehicle air pressure value P with the first air pressure threshold value P1 and the second air pressure threshold value P2 set for the vehicle in real time according to the air volume level information of the road ahead, wherein the first air pressure threshold value P1 is the minimum air pressure value to maintain the braking performance of the vehicle, and the second air pressure threshold value P2 is the air pressure value when the air compressor is turned on at medium and low speeds, which is greater than the first air pressure threshold value P1; If the gas consumption level is level 1 and P≤P1; or the air compressor is started and the current vehicle air pressure change value is negative; then the air compressor is controlled to enter the high speed working mode; If the gas consumption level is level one and P1<P≤P2; or, the gas consumption level is level two and P≤P1; then the air compressor is controlled to enter the medium speed working mode; If the gas consumption level is level 2 and P1<P≤P2; or, the gas consumption level is level 3 and P≤P1; the air compressor is controlled to enter the low speed working mode; If none of the above conditions are met, the status of the air compressor will not be adjusted.

[0007] In one embodiment of the present invention, the current humidity value H in the brake air pipeline is obtained by a humidity sensor installed in the air pipeline and transmitted to the vehicle controller via a signal.

[0008] In one scheme of the present invention: the specific prediction method of the E-control big data platform is that the E-control big data platform obtains map and road condition information, predicts the gas consumption level required for the driving section, and updates the gas consumption level information according to the driver's driving habits and the historical gas consumption level information of the driving section.

[0009] In one embodiment of the present invention, the current vehicle air pressure value P is the lower value of the air pressure values ​​of the front and rear brake air reservoirs.

[0010] In one embodiment of the present invention, the lower value of the front and rear brake air reservoir pressure values ​​is collected by the instrument air pressure sensor and sent to the CAN bus, and then read and compared by the vehicle controller.

[0011] In one embodiment of the present invention, when the air compressor enters the high speed working mode, the air compressor stops until the vehicle controller receives the stop signal sent by the drying tank. At this time, the air compressor shutdown method should also include: 1. The air compressor will stop after a delay of t1 after starting. 2. After the current vehicle air pressure value P reaches the upper limit threshold of vehicle safe driving, the vehicle will shut down after a delay of t2.

[0012] In one scheme of the present invention: when the air compressor enters the medium and low speed working mode, the air compressor stops until the current vehicle air pressure value P> the third air pressure threshold value P3. At this time, the air compressor shutdown method should also include: the air compressor is shut down after a delay of t3 after starting to work.

[0013] In one embodiment of the present invention, the third air pressure threshold value P3 is the air pressure value at which the air compressor stops operating at medium and low speeds. The air pressure value is greater than the second air pressure threshold value P2 and less than the drying tank cut-off pressure threshold value P4.

[0014] In one embodiment of the present invention, the shutdown signal sent by the drying tank is a hard-wired signal sent to the vehicle controller after the current vehicle air pressure value P reaches the drying tank cut-off pressure threshold value P4. When the hard-wired signal is lost, the air compressor shutdown signal loss fault is reported.

[0015] In one solution of the present invention: the E-control big data platform information is exchanged with the vehicle controller through the vehicle-mounted monitoring terminal.

[0016] Beneficial effects of the present invention: This application performs graded control on the target vehicle's air compressor based on the current humidity value H in the target vehicle's brake air pipeline, the air usage level information of the road ahead, and the target vehicle's current vehicle air pressure value P, so that the air compressor is in different working modes under different conditions, effectively reducing energy consumption and noise during vehicle operation, and keeping the vehicle air pressure value within the optimal air pressure range as much as possible, thereby improving ride comfort. At the same time, the control method of this application can timely remove moisture in the brake air pipeline, protect the pipeline and brake components, and increase the service life of the components.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easy to understand from the description of the embodiments in conjunction with the following drawings. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. Among them: Figure 1 The present invention is a schematic diagram of the control flow of the brake air pipeline control method of a pure electric vehicle. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0021] See also Figure 1 The present invention is a pure electric vehicle brake air pipeline control method, which is applied to pure electric vehicles and is executed after high pressure is applied to the vehicle. Specifically, it includes the following steps: Step 1: Obtain the current humidity value H in the brake air pipeline of the target vehicle, the air volume level information of the road ahead, and the current vehicle air pressure value P of the target vehicle.

[0022] In one of the embodiments of the present invention, the current humidity value H in the brake air pipeline can be obtained by a humidity sensor installed in the air pipeline and transmitted to the vehicle controller through a wired or wireless signal connection.

[0023] In one embodiment of the present invention, the gas usage level information of the road ahead is obtained through prediction by the E-control big data platform. The E-control big data platform information can be exchanged with the vehicle controller through the vehicle monitoring terminal. The gas usage level information of the road ahead can be divided into three levels, of which the first level is the highest level.

[0024] In one of the embodiments of the present invention, the specific method for predicting and obtaining the gas usage level information of the road condition ahead through the E-control big data platform can be: obtaining map and road condition information (including but not limited to road conditions, route length, intersections, number of traffic lights, whether there is slippery weather such as rain or snow, etc.) through the E-control big data platform, predicting the gas usage level required for the driving section, and updating the gas usage level information based on the driver's driving habits and the historical gas usage level information of the driving section. The E-control platform can store the actual gas usage information of each section over a period of time to help judge the gas usage level.

[0025] In one of the embodiments of the present invention, as an example, the specific process of predicting and obtaining the gas usage level information of the road condition ahead through the E-control big data platform can be: first, retrieve the historical gas usage level information of the driving section, and retrieve the road condition information, driver information, traffic flow information, road surface status information, etc. corresponding to the historical gas usage level information. Then, based on the historical gas usage level information, refer to the changes in real-time road condition information, traffic flow information, road surface status information, etc. to increase or decrease the historical gas usage level information as the predicted road condition ahead gas usage level information. If the real-time traffic flow ahead is high, the usage may be improved. Therefore, a certain amount can be added to the historical gas usage level information as the predicted road condition ahead gas usage level information, and vice versa. Furthermore, after obtaining the predicted road condition ahead gas usage level information, a certain margin can be added to ensure that the set predicted road condition ahead gas usage level information can meet the vehicle driving and usage requirements.

[0026] In one embodiment of the present invention, the current vehicle air pressure value P is the lower value of the front and rear brake air reservoir air pressure values. The lower value of the front and rear brake air reservoir air pressure values ​​can be collected by the instrument air pressure sensor and sent to the CAN bus, and then read and compared by the vehicle controller.

[0027] Step 2: Compare the current humidity value H in the brake air pipeline with the set humidity value h: if H≥h, control the air compressor to enter the high-speed working mode; if H<h, proceed to step 3.

[0028] In one embodiment of the present invention, the set humidity value h is the minimum humidity value set based on experience to prevent water accumulation in the air pipeline, that is, the critical value at which water accumulation may occur in the air pipeline, and is set by technical personnel in this field based on experience (for example, the set humidity value h can be 35%).

[0029] Specifically, when the comparison result H≥h is obtained, it means that there is a risk of water accumulation in the brake air pipeline. The air compressor is controlled to enter the high-speed working mode, so that the air pressure of the whole vehicle quickly reaches the dry tank cut-off pressure threshold and then exhausts the air to prevent water accumulation in the brake air pipeline of the whole vehicle.

[0030] At this time, the air compressor will not stop until the vehicle controller receives the stop signal from the drying tank.

[0031] Step 3: Compare the current vehicle air pressure value P with the first air pressure threshold value P1 and the second air pressure threshold value P2 set for the vehicle in real time according to the air consumption level information of the road condition ahead: If the air consumption level is level one and P≤P1, or the air compressor is started and the current vehicle air pressure change value is negative, then control the air compressor to enter the high-speed working mode; if the air consumption level is level one and P1<P≤P2, or the air consumption level is level two and P≤P1, then control the air compressor to enter the medium-speed working mode; if the air consumption level is level two and P1<P≤P2, or the air consumption level is level three and P≤P1, then control the air compressor to enter the low-speed working mode; if none of them are met, the state of the air compressor will not be adjusted.

[0032] The first air pressure threshold value P1 is the minimum air pressure value for maintaining the braking performance of the whole vehicle, and is set by those skilled in the art based on experience (for example, it may be 850 kPa for a public bus).

[0033] The second air pressure threshold value P2 is the air pressure value when the air compressor is turned on at medium and low speeds. This air pressure value is greater than the first air pressure threshold value P1 and is set by those skilled in the art based on empirical values ​​(for example, it can be 920 kPa for buses).

[0034] After real-time comparison, if the gas consumption level is level one and P≤P1, or the air compressor has been started and the current vehicle air pressure change value is negative, the air compressor is controlled to enter the high-speed working mode. At this time, the vehicle is in a situation where the gas demand is large and the vehicle air pressure value P is lower than the vehicle safe driving pressure value, or the gas demand is large and the current working mode of the air compressor is insufficient to meet the gas demand. Using high-speed operation can quickly bring the vehicle air pressure to a safe range to ensure driving safety.

[0035] After real-time comparison, if the gas consumption level is level one and P1<P≤P2, or the gas consumption level is level two and P≤P1, the air compressor is controlled to enter the medium speed working mode; If the gas consumption level is level 2 and P1<P≤P2, or the gas consumption level is level 3 and P≤P1, the air compressor is controlled to enter the low speed working mode; At this time, the noise generated by the air compressor is relatively small, and this method reduces the time that the air compressor works at a high speed, so that the air pressure value of the whole vehicle is kept within the optimal air pressure range as much as possible, which greatly reduces the noise during the operation of the whole vehicle and improves the riding comfort.

[0036] If none of the above conditions are met, the status of the air compressor will not be adjusted. At this time, the vehicle air pressure is within the safe driving pressure range and no adjustment is required.

[0037] In one embodiment of the present invention, when the air compressor enters the high speed working mode, the air compressor stops until the vehicle controller receives the stop signal sent by the drying tank. At this time, the air compressor shutdown method should also include: 1. The air compressor will be shut down after a delay of t1 after it is started to prevent the air compressor from continuing to work without stopping due to air leakage in the vehicle's air pipeline; 2. After the current vehicle air pressure value P reaches the upper limit threshold of vehicle safe driving, the vehicle will be shut down after a delay of t2 to avoid the situation where the vehicle controller has not received the shutdown signal sent by the drying tank when the vehicle air pressure has reached the upper limit threshold of vehicle safe driving and continues to work without shutting down.

[0038] The above t1 and t2 are set by those skilled in the art based on empirical values ​​(for example, time t1 may be 2 minutes, and time t2 may be 12 seconds).

[0039] In one embodiment of the present invention, when the air compressor enters the medium and low speed working mode, the air compressor stops until the current vehicle air pressure value P> the third air pressure threshold value P3. At this time, the air compressor shutdown method should also include: the air compressor is shut down after a delay of t3 after starting to work, to prevent the air compressor from continuing to work without stopping due to air leakage in the vehicle air pipeline. The above t3 is set by technicians in this field based on experience (for example, time t3 can be 3 minutes).

[0040] In one embodiment of the present invention, the third air pressure threshold value P3 is the air pressure value at which the air compressor stops operating at medium and low speeds. The air pressure value is greater than the second air pressure threshold value P2 and less than the drying tank cut-off pressure air pressure threshold value P4, and is set by a person skilled in the art based on experience.

[0041] In one of the embodiments of the present invention, the shutdown signal issued by the above-mentioned dry tank is a hard-line signal sent to the vehicle controller after the current vehicle air pressure value P reaches the dry tank cut-off pressure threshold value P4. When the hard-line signal is lost, the air compressor shutdown signal loss fault is reported, which helps to better judge the system status.

[0042] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of application of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. A pure electric vehicle brake air pipeline control method, characterized in that: The steps include: Step 1: Obtain the current humidity value H in the brake air pipeline of the target vehicle, the air usage level information of the road ahead, and the current vehicle air pressure value P of the target vehicle; the air usage level information of the road ahead is obtained through prediction by the E-control big data platform, and the air usage level information of the road ahead is divided into three levels, of which the first level is the highest level; Step 2: Compare the current humidity value H in the brake air pipeline with the set humidity value h: If H≥h, the air compressor is controlled to enter high speed working mode; If H<h, go to step 3; Step 3: Compare the current vehicle air pressure value P with the first air pressure threshold value P1 and the second air pressure threshold value P2 set for the vehicle in real time according to the air volume level information of the road ahead, wherein the first air pressure threshold value P1 is the minimum air pressure value to maintain the braking performance of the vehicle, and the second air pressure threshold value P2 is the air pressure value when the air compressor is turned on at medium and low speeds, which is greater than the first air pressure threshold value P1; If the gas consumption level is level 1 and P≤P1; or the air compressor is started and the current vehicle air pressure change value is negative; then the air compressor is controlled to enter the high speed working mode; If the gas consumption level is level one and P1<P≤P2; or, the gas consumption level is level two and P≤P1; then the air compressor is controlled to enter the medium speed working mode; If the gas consumption level is level 2 and P1<P≤P2; or, the gas consumption level is level 3 and P≤P1; the air compressor is controlled to enter the low speed working mode; If none of the above conditions are met, the status of the air compressor will not be adjusted.

2. A pure electric vehicle brake air pipeline control method according to claim 1, characterized in that: The current humidity value H in the brake air pipeline is obtained by the humidity sensor installed in the air pipeline and transmitted to the vehicle controller through a signal.

3. A pure electric vehicle brake air pipeline control method according to claim 1, characterized in that: The specific prediction method of the E-control big data platform is that the E-control big data platform obtains map and road condition information, predicts the gas consumption level required for the driving section, and updates the gas consumption level information based on the driver's driving habits and the historical gas consumption level information of the driving section.

4. A pure electric vehicle brake air pipeline control method according to claim 1, characterized in that: The current vehicle air pressure value P is the lower value of the front and rear brake air reservoir pressure values.

5. A pure electric vehicle brake air pipeline control method according to claim 4, characterized in that: The lower value of the front and rear brake air reservoir pressure values ​​is collected by the instrument air pressure sensor and sent to the CAN bus, and then read and compared by the vehicle controller.

6. A pure electric vehicle brake air pipeline control method according to claim 1, characterized in that: When the air compressor enters the high speed working mode, the air compressor will not stop until the vehicle controller receives the stop signal from the drying tank. At this time, the air compressor shutdown method should also include: The air compressor will stop after a delay of t1 after it starts working; After the current vehicle air pressure value P reaches the upper limit threshold of vehicle safe driving, the vehicle will shut down after a delay of t2.

7. A pure electric vehicle brake air pipeline control method according to claim 1, characterized in that: When the air compressor enters the medium and low speed working mode, the air compressor will not stop until the current vehicle air pressure value P> the third air pressure threshold value P3. At this time, the air compressor shutdown method should also include: the air compressor is shut down after a delay of t3 after starting to work.

8. A pure electric vehicle brake air pipeline control method according to claim 7, characterized in that: The third air pressure threshold value P3 is the air pressure value at which the air compressor stops operating at medium and low speeds. This air pressure value is greater than the second air pressure threshold value P2 and less than the drying tank cut-off pressure air pressure threshold value P4.

9. A pure electric vehicle brake air pipeline control method according to claim 8, characterized in that: The shutdown signal issued by the dryer tank is a hard-wired signal sent to the vehicle controller after the current vehicle air pressure value P reaches the dryer tank cut-off pressure threshold P4. When the hard-wired signal is lost, the air compressor shutdown signal loss fault is reported.

10. A pure electric vehicle brake air pipeline control method according to claim 9, characterized in that: The information of the E-control big data platform is exchanged with the vehicle controller through the on-board monitoring terminal.

Images