Carbon tank desorption system and method
By designing a venturi-structured carbon canister desorption system in a range-extended electric vehicle, and utilizing the exhaust pipe bypass branch and engine control unit adjustment, the problem of low carbon canister desorption efficiency in high-altitude areas was solved, achieving efficient fuel vapor combustion and engine performance protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-21
- Publication Date
- 2026-03-10
AI Technical Summary
In high-altitude areas, the low atmospheric pressure and insufficient vacuum in the engine intake manifold of range-extended electric vehicles result in low carbon canister desorption efficiency, affecting engine power performance. Current technologies require sacrificing power performance to maintain desorption.
Design a carbon canister desorption system, which includes a venturi-structured negative pressure pipeline and an exhaust pipeline bypass branch. The system utilizes the high temperature of engine exhaust to burn fuel vapors in the carbon canister, and adjusts the desorption route and the opening of the exhaust control valve through the engine control unit to ensure that the fuel vapors are fully burned in the exhaust pipeline.
It improves the desorption efficiency of the carbon canister, prevents fuel vapor from being released into the atmosphere, protects engine performance, prevents catalytic converter overheating, and resolves the contradiction between engine performance and carbon canister desorption, making it suitable for high-altitude environments.
Smart Images
Figure CN121630610A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of automobile carbon canister desorption, in particular to a carbon canister desorption system and method. BACKGROUND
[0002] The carbon canister desorption mode of the extended-range electric vehicle follows the control method of the traditional fuel vehicle, mainly through the negative pressure of the intake system under the engine running state to suck the fuel vapor stored in the carbon canister into the intake pipe and into the engine for combustion to avoid polluting the environment by being discharged into the atmosphere. In order to pursue economy and NVH performance, the extended-range electric vehicle generally controls the engine to operate at medium-low speed and high load, and the vacuum degree that can be generated in the intake manifold is small, resulting in low desorption efficiency. Especially in the plateau area, the atmospheric pressure is low, and the performance of the engine will also be greatly reduced. Therefore, the contradiction between carbon canister desorption and engine power performance is highlighted. In order to maintain normal carbon canister desorption, the power performance is often sacrificed, and the naturally aspirated engine is particularly obvious. SUMMARY
[0003] The present application provides a carbon canister desorption system and method to solve the technical problems in the prior art.
[0004] The technical solution of the present application to solve the above technical problems is as follows: The present application protects a carbon canister desorption system in the first aspect, comprising a carbon canister, an engine and a negative pressure pipeline; The negative pressure pipeline is a Venturi structure pipeline that is first contracted and then gradually expanded along the engine exhaust direction, and the second intake port B, the first intake port A and the gas outlet C of the negative pressure pipeline are sequentially arranged in the pipeline along the engine exhaust direction. The negative pressure pipeline is communicated with the exhaust pipeline of the engine through the second intake port B and the gas outlet C, forming a bypass branch of the exhaust pipeline; The carbon canister has a first exhaust pipeline and a second exhaust pipeline, and the first exhaust pipeline is communicated with the intake manifold of the engine to constitute an intake desorption route of the engine; The second exhaust pipeline of the carbon canister is communicated with the first intake port A of the negative pressure pipeline, so that the negative pressure is generated in the negative pressure pipeline to suck the gas stored in the carbon canister into the exhaust pipeline of the engine for combustion, thereby constituting an exhaust desorption route of the engine.
[0005] As a further technical solution, the negative pressure pipeline comprises a contraction section, a throat section and a diffusion section connected in sequence; The inner diameter of the contraction section is gradually reduced, and the second intake port B is located at the inlet of the contraction section; The throat section is a smooth section, and the first intake port A is located at the throat section; The diffuser section has a gradually increasing inner diameter, and the outlet C is located at the outlet of the diffuser section.
[0006] As a further technical solution, an exhaust control valve is provided on the second exhaust pipe of the carbon canister to control the opening and closing of the exhaust desorption route.
[0007] As a further technical solution, a heat dissipation component is provided on the pipe section between the exhaust control valve and the negative pressure pipeline.
[0008] As a further technical solution, a front oxygen sensor is also included, which is located on the exhaust pipe of the engine, such that the negative pressure pipe is located between the engine and the front oxygen sensor; And / or, It also includes a catalytic converter, which is connected to the end of the engine's exhaust pipe.
[0009] As a further technical solution, an engine control unit is also included, which is signal-connected to the engine, the exhaust control valve, and the front oxygen sensor.
[0010] As a further technical solution, a carbon canister control valve is provided on the first exhaust pipe, and the engine control unit is signal-connected to the carbon canister control valve.
[0011] A second aspect of this invention protects a carbon canister desorption method, the method being used to control a carbon canister desorption system as described in the first aspect, the desorption method comprising: When the desorption capacity of the intake manifold in the engine is insufficient, the exhaust desorption route of the engine is activated.
[0012] As a further technical solution, it includes: when the exhaust desorption route of the engine is activated, the gas in the carbon canister enters the exhaust pipe of the engine in sequence through the second exhaust pipe, the first intake port A, and the exhaust port C, and the exhaust gas in the exhaust pipe combusts the gas from the carbon canister.
[0013] As a further technical solution, when the exhaust desorption circuit is working, the exhaust temperature of the engine is greater than or equal to 450°C.
[0014] The beneficial effects of this invention are: 1. The outlet of the carbon canister is provided with two branches. One branch is connected to the intake manifold of the engine to form an intake desorption route, and the other branch is connected to the exhaust pipe of the engine. Through the Venturi structure characteristics of the negative pressure pipe, a negative pressure is formed in the negative pressure pipe to draw in the gas in the carbon canister and transmit it to the exhaust pipe for combustion, thereby improving the desorption efficiency of the carbon canister and effectively preventing fuel vapor from being discharged into the atmosphere. 2. A heat dissipation component is installed between the exhaust control valve and the negative pressure pipeline to ensure that the temperature at the connection between the negative pressure pipeline and the engine's exhaust pipeline does not become too high and will not damage the engine's exhaust pipeline. In addition, the engine control unit is connected to the engine, exhaust control valve, front oxygen sensor, etc., and can select whether to open the exhaust desorption route and the opening degree of the exhaust control valve according to the desorption capacity of the intake desorption route, so as to ensure that the fuel vapor can be fully burned in the engine exhaust pipe and will not cause the catalyst to overheat and be damaged. 3. In the carbon canister desorption method, when the desorption capacity of the intake desorption route is insufficient, the exhaust desorption route is opened, and the high temperature of the engine exhaust gas is used to burn the gas from the carbon canister; in addition, the engine control unit receives the signal from the front oxygen sensor and controls the opening of the exhaust control valve to adjust the air-fuel ratio during desorption and avoid the problem of catalyst overheating. Furthermore, this method solves the problem of engine performance sacrifice caused by intake negative pressure desorption. Attached Figure Description
[0015] Figure 1 This is a structural connection diagram of a carbon canister desorption system according to the present invention, with the arrows indicating the direction of gas movement; Figure 2 This is a partially enlarged structural diagram of a carbon canister desorption system according to the present invention, with the arrow indicating the direction of gas movement.
[0016] The attached diagram lists the components represented by each number as follows: Carbon canister 1, first outlet pipe 11, carbon canister control valve 11a, second outlet pipe 12; Engine 2; Negative pressure pipeline 3, contraction section 31, throat section 32, diffuser section 33; Exhaust control valve 4, heat sink 41; 5. Exhaust pipe; 6. Fuel tank; 7. Catalyst; 8. Front oxygen sensor; 9. Engine control unit. Detailed Implementation
[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0018] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0019] In the description of this application, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.
[0020] Example 1 See Figure 1 , Figure 2 This embodiment provides a carbon canister desorption system, including a carbon canister 1, an engine 2, and a negative pressure pipeline 3. The negative pressure pipeline 3 has a Venturi structure pipe that first contracts and then gradually expands along the engine exhaust direction. The second air inlet B, the first air inlet A, and the air outlet C of the negative pressure pipeline 3 are sequentially arranged along the engine exhaust direction. The negative pressure pipeline 3 is connected to the exhaust pipe 5 of the engine 2 through the second air inlet B and the air outlet C, forming a bypass branch of the exhaust pipe 5. The carbon canister 1 has a first air outlet pipe 11 and a second air outlet pipe 12. The first air outlet pipe 11 is connected to the intake manifold of the engine 2 to form the intake desorption route of the engine 2. The second air outlet pipe 12 of the carbon canister 1 is connected to the first air inlet A of the negative pressure pipeline 3, so that a negative pressure is generated in the negative pressure pipeline 3 to draw the gas stored in the carbon canister 1 into the exhaust pipe 5 of the engine 2 for combustion, thereby forming the exhaust desorption route of the engine 2.
[0021] It should be noted that the air inlet of the carbon canister 1 is connected to the fuel tank 6 and is used to collect, store and purify fuel vapor in order to reduce emissions and improve fuel economy.
[0022] It should be noted that the negative pressure pipeline 3 has a venturi effect, that is, it generates negative pressure to draw the fuel vapor stored in the carbon canister 1 into the exhaust pipeline 5 of the engine 2 through the first air intake port A, so as to use the high temperature exhaust gas in the exhaust pipeline 5 to burn the fuel vapor.
[0023] Furthermore, the negative pressure pipeline 3 includes a contraction section 31, a throat section 32, and a diffuser section 33 connected in sequence; the inner diameter of the contraction section 31 gradually decreases, and the second air inlet B is located at the inlet of the contraction section 31; the throat section 32 is a smooth section, and the first air inlet A is located at the throat section 32; the inner diameter of the diffuser section 33 gradually increases, and the air outlet C is located at the outlet of the diffuser section 33.
[0024] For example, the contraction section 31, the throat section 32, and the diffuser section 33 can be integrally formed to improve stability; for example, the negative pressure pipeline 3 can be the internally connected contraction section 31, throat section 32, and diffuser section 33 to form a Venturi effect.
[0025] It should be noted that the specific dimensions of the contraction section 31, the throat section 32, and the diffusion section 33 are determined according to the negative pressure requirements.
[0026] It should be noted that a dust filter is connected to the atmospheric outlet pipe of the carbon canister 1 to ensure normal gas exchange between the carbon canister 1 and the atmosphere, indirectly helping to balance the air pressure in the fuel tank 6 and avoiding problems such as negative pressure deformation of the fuel tank 6 and damage to the fuel pump due to pipe blockage.
[0027] See Figure 1 Furthermore, it also includes a catalytic converter 7, the end of the exhaust pipe 5 of the engine 2 is connected to the catalytic converter 7 to purify the gas from the exhaust pipe 5. During use, a muffler (not labeled in the figure) is connected to the tail of the catalytic converter 7 to ensure the exhaust system is quiet and improve comfort.
[0028] See Figure 1 In the specific implementation process, the exhaust control valve 4 is provided on the second exhaust pipe 12 of the carbon canister 1 to control the opening and closing of the exhaust desorption route; a heat sink 41 is provided on the pipe section between the exhaust control valve 4 and the negative pressure pipe 3, so that the temperature of the gas (e.g., fuel vapor) entering the exhaust pipe 5 has been cooled by the heat sink 41, which can avoid damage to the subsequent structure and improve the stability and lifespan of the overall system. That is, the heat sink 41 is provided on the second exhaust pipe 12.
[0029] For example, the heat sink 41 is a spiral cooling pipe to cool the gas from the carbon canister 1 before it enters the negative pressure pipe.
[0030] SeeFigure 1 In the specific implementation process, the system of this embodiment also includes a front oxygen sensor 8, which is located on the exhaust pipe 5 of the engine 2, so that the negative pressure pipe 3 is located between the engine 2 and the front oxygen sensor 8.
[0031] It should be noted that the front oxygen sensor 8 is used to monitor the oxygen content of the exhaust gas in the exhaust pipe 5 in real time.
[0032] See Figure 1 Furthermore, the system in this embodiment also includes an engine control unit 9, which is signal-connected to the engine 2, the exhaust control valve 4, and the front oxygen sensor 8. After receiving the monitoring value from the front oxygen sensor 8, the engine control unit 9 regulates the opening and closing of the exhaust control valve 4, and its opening degree. That is, it can control the opening degree according to demand and exhaust temperature to ensure, for example, that fuel vapor can be fully combusted in the exhaust pipe 5 without overheating and damaging the catalytic converter 7, while effectively preventing fuel vapor from being released into the atmosphere.
[0033] See Figure 1 In the specific implementation process, a carbon canister control valve 11a is provided on the first exhaust pipe 11. The engine control unit 9 is signal connected to the carbon canister control valve 11a. The engine control unit 9 can control the opening and closing of the carbon canister control valve 11a and accurately issue control commands after receiving the operating signal of the engine 2 in real time. The engine 2 and the engine control unit 9 work together to realize the core functions of engine 2 such as starting, combustion, and operating condition adjustment.
[0034] In this embodiment, two branches are provided at the outlet of the carbon canister 1. One branch is connected to the intake manifold of the engine 2 to form an intake desorption route, and the other branch is connected to the exhaust pipe 5 of the engine 2. The negative pressure pipe 3 is designed with a Venturi effect structure to create negative pressure and draw fuel vapor into the exhaust pipe 5, thereby improving the desorption efficiency of the carbon canister 1. At the same time, it can be applied to high-altitude environments to reduce the contradiction between the desorption of the carbon canister 1 and the power performance of the engine 2.
[0035] Example 2 This embodiment provides a carbon canister desorption method, which is used to control a carbon canister desorption system as described in Embodiment 1. The desorption method includes: When the desorption capacity of the intake manifold in engine 2 is insufficient, the exhaust desorption route of engine 2 is activated. That is, the engine 2 and the front oxygen sensor 8 can be monitored in real time by the engine control unit 9 to control the opening and closing of the carbon canister control valve 11a and the exhaust control valve 4.
[0036] For example, the engine control unit 9 identifies the altitude environment based on atmospheric pressure. When the altitude is higher than 2km, the gas in the carbon canister 1 enters the exhaust pipe 5 of the engine 2 sequentially through the second exhaust pipe 12, the first intake port A, and the exhaust port C. The exhaust gas in the exhaust pipe 5 combusts the gas from the carbon canister 1, mainly relying on the exhaust desorption route. That is, at this time, the carbon canister control valve 11a is closed, the exhaust control valve 4 is open, and the exhaust gas discharged from the exhaust manifold of the engine 2 is divided into two paths. One path enters the constriction section 31 through the second intake port B, combined with the structural characteristics of the negative pressure pipe 3. This creates a negative pressure in the negative pressure pipeline 3, causing the fuel gas in the carbon canister 1 to first be cooled by the heat sink 41, and then enter the throat section 32 through the first air inlet A of the negative pressure pipeline 3 to mix with the exhaust gas discharged from the exhaust manifold in this section. Part of the fuel gas is burned by the exhaust gas in the throat section 32, and the remaining fuel gas and exhaust gas enter the diffuser section 33 and are discharged to the exhaust pipeline through the air outlet C; another path travels along the original route of the exhaust pipeline 5, burning the fuel gas from the negative pressure pipeline 3, reducing the contradiction between the desorption of the carbon canister 1 and the power performance of the engine 2, and ensuring the performance of the engine 2.
[0037] During the above process, the engine control unit 9 monitors the signal of the front oxygen sensor 8 in real time to control the opening of the exhaust control valve 4, adjust the air-fuel ratio during desorption, and avoid overheating of the catalytic converter 7.
[0038] It should be noted that when the exhaust desorption circuit is working, the exhaust temperature of the engine 2 is greater than or equal to 450°C, so as to have a sufficiently high temperature to burn the fuel vapor from the negative pressure pipeline 3.
[0039] It should be noted that when the desorption capacity of the intake manifold in engine 2 is sufficient, it is not necessary to open the exhaust desorption route.
[0040] This method solves the problem of engine performance loss caused by intake negative pressure desorption.
[0041] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.
[0042] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0043] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A carbon canister desorption system characterized by, The carbon tank (1), the engine (2) and the negative pressure pipeline (3); The negative pressure pipeline (3) is internally provided with a Venturi structure pipeline gradually expanding after being contracted along the exhaust direction of the engine, and the second air inlet B, the first air inlet A and the air outlet C of the negative pressure pipeline (3) are sequentially arranged in the pipeline along the exhaust direction of the engine (2), the negative pressure pipeline (3) is communicated with the exhaust pipeline (5) of the engine (2) through the second air inlet B and the air outlet C, thereby forming a bypass branch of the exhaust pipeline (5); The carbon tank (1) is provided with a first air outlet pipeline (11) and a second air outlet pipeline (12), the first air outlet pipeline (11) is communicated with the air inlet manifold of the engine (2) to form an air desorption route of the engine (2); the second air outlet pipeline (12) of the carbon tank (1) is communicated with the first air inlet A of the negative pressure pipeline (3), so that the gas stored in the carbon tank (1) is sucked into the exhaust pipeline (5) of the engine (2) to be combusted, thereby forming an exhaust desorption route of the engine (2).
2. A carbon canister desorption system according to claim 1, wherein The negative pressure pipeline (3) comprises a contraction section (31), a throat section (32) and a diffusion section (33) connected in sequence; The inner diameter of the contraction section (31) is gradually reduced, and the second air inlet B is located at the inlet of the contraction section (31); The throat section (32) is a smooth section, and the first air inlet A is located at the throat section (32); The inner diameter of the diffusion section (33) is gradually expanded, and the air outlet C is located at the outlet of the diffusion section (33).
3. A carbon canister desorption system according to claim 1, wherein An exhaust control valve (4) is arranged on the second air outlet pipeline (12) of the carbon tank (1) to control the opening and closing of the exhaust desorption route.
4. A carbon canister desorption system according to claim 3, wherein A heat dissipation member (41) is arranged on the pipeline section between the exhaust control valve (4) and the negative pressure pipeline (3).
5. A carbon canister desorption system according to claim 1, wherein Further comprising a front oxygen sensor (8), the front oxygen sensor (8) is arranged on the exhaust pipeline (5) of the engine (2), so that the negative pressure pipeline (3) is located between the engine (2) and the front oxygen sensor (8); And / or, Further comprising a catalyst (7), the end of the exhaust pipeline (5) of the engine (2) is connected with the catalyst (7).
6. A carbon canister desorption system according to claim 5, wherein Further comprising an engine control unit (9), the engine control unit (9) is signal connected with the engine (2), the exhaust control valve (4) and the front oxygen sensor (8).
7. A carbon canister desorption system according to claim 6, wherein A carbon tank control valve (11a) is arranged on the first air outlet pipeline (11), and the engine control unit (9) is signal connected with the carbon tank control valve (11a).
8. A carbon can desorption method characterized by, The method is used for controlling the carbon tank desorption system according to any one of claims 1-7, and the desorption method comprises: When the desorption capacity of the air inlet manifold of the engine (2) is insufficient, the exhaust desorption route of the engine (2) is enabled.
9. The carbon can desorption method according to claim 8, characterized by, When the exhaust desorption route of the engine (2) is enabled, the gas in the carbon tank (1) enters the exhaust pipe (5) of the engine (2) in turn through the second gas outlet pipeline (12), the first gas inlet A, and the gas outlet C, and is burned by the exhaust gas in the exhaust pipe (5).
10. The method of claim 8, wherein the desorption is performed at a temperature of 200- 300°C. When the exhaust desorption route is working, the exhaust temperature of the engine (2) is greater than or equal to 450 DEG C.