Carbon canister desorption method, system, vehicle controller, and vehicle

Abstract

This invention relates to the field of vehicle carbon canister desorption technology. The invention discloses a method, system, vehicle controller, and vehicle for carbon canister desorption in hybrid vehicles. The method includes: after the hybrid vehicle is started, acquiring the State of Charge (SOC) value of the hybrid vehicle's power battery; controlling the engine to obtain a preset speed based on the SOC value, thereby controlling the carbon canister solenoid valve of the hybrid vehicle to obtain the desorption flow rate; controlling the airflow hydrocarbon sensor of the hybrid vehicle to acquire carbon canister load information in real time; and performing carbon canister desorption operation based on the carbon canister load information. This invention can accurately and reliably acquire carbon canister load information, quickly and timely desorb fuel vapor from the carbon canister, and reduce environmental pollution caused by fuel vapor emissions into the atmosphere.

Description

Technical Field

[0001] This invention relates to the field of carbon canister desorption technology for vehicles, specifically to a carbon canister desorption method, system, vehicle controller, and vehicle for hybrid vehicles. Background Technology

[0002] Currently, due to the volatility of gasoline, gasoline-powered vehicles require carbon canisters to adsorb fuel vapors from the fuel tank. After the engine starts, the vacuum in the engine intake manifold draws fuel vapors from the carbon canister into the engine cylinders for combustion, preventing direct release of fuel vapors into the atmosphere and causing environmental pollution. For hybrid vehicles, the driver can charge the battery to allow the vehicle to operate in pure electric mode for extended periods, with the engine only starting when the battery's state of charge (SOC) is low or when the vehicle requires additional driving torque. This results in hybrid vehicles having significantly less engine operation time and opportunities compared to gasoline vehicles during daily use. Consequently, fuel vapors in the carbon canister cannot be desorbed in time and are released into the atmosphere, causing environmental pollution. Existing technologies include schemes that calculate fuel evaporation in the fuel tank using different carbon canister load models. However, the computational mechanism for these carbon canister load models is extremely complex, requiring significant development effort. Furthermore, the accuracy and robustness of currently used carbon canister load models are poor, thus failing to accurately and promptly desorb fuel vapors from the carbon canister. Summary of the Invention

[0003] This invention provides a method, system, vehicle controller, and vehicle for desorbing carbon canisters in hybrid vehicles, which can accurately and timely desorb fuel vapors from the carbon canisters, reducing environmental pollution caused by fuel vapor emissions into the atmosphere.

[0004] A method for carbon canister desorption in a hybrid vehicle, comprising:

[0005] After the hybrid vehicle is started, obtain the SOC value of the hybrid vehicle's power battery;

[0006] The engine speed is controlled according to the SOC value to obtain a preset speed, so as to control the carbon canister solenoid valve of the hybrid vehicle to obtain the desorption flow.

[0007] The hydrocarbon sensor controls the airflow of hybrid vehicles and obtains carbon canister load information in real time.

[0008] Perform carbon canister desorption operation based on carbon canister load information.

[0009] Optionally, the engine is controlled to obtain a preset speed based on the SOC value, including:

[0010] When the SOC value is greater than or equal to the preset SOC threshold, the vehicle speed of the hybrid vehicle is collected in real time.

[0011] When the vehicle speed is greater than or equal to the preset speed, the electric motor of the hybrid vehicle will drive the engine to the first preset speed.

[0012] Optionally, after the engine reaches the first preset speed, it further includes:

[0013] Set the engine to disable fuel injection and ignition, set the duty cycle of the carbon canister solenoid valve to the first duty cycle, and set the engine throttle opening to the preset opening.

[0014] Optionally, the engine is controlled to obtain a preset speed based on the SOC value, including:

[0015] When the SOC value is less than the preset SOC threshold, the engine is detected in real time to see if it starts.

[0016] When engine start is detected, the engine speed is controlled to be adjusted to a second preset speed, which is greater than or equal to the first preset speed.

[0017] Optionally, after the engine reaches the second preset speed, the following steps are also included:

[0018] Control the engine torque output to a preset torque;

[0019] When the engine is warmed up to the first preset temperature, the duty cycle of the carbon canister solenoid valve is set to the second duty cycle.

[0020] Optionally, the desorption flow rate is obtained by controlling the carbon canister solenoid valve of the hybrid vehicle, specifically:

[0021] Control the opening of the carbon canister solenoid valve and ensure that the outlet pressure of the carbon canister solenoid valve is less than the inlet pressure.

[0022] Optionally, carbon canister desorption operations are performed based on the carbon canister load information, including:

[0023] When the carbon canister load is greater than or equal to the first preset load threshold, the current state of the engine is obtained, and the engine enters the carbon canister forced desorption mode to execute the forced desorption strategy corresponding to the current state.

[0024] Optionally, a forced decoupling strategy corresponding to the current state is executed, including:

[0025] When the engine is currently driven by an electric motor, a first forced decoupling strategy is executed. The first forced decoupling strategy includes:

[0026] After controlling the engine's fuel injectors to inject fuel and the spark plugs to ignite, and setting the duty cycle of the carbon canister solenoid valve to 0%, start the engine.

[0027] When the engine is warmed up to the second preset temperature, the duty cycle of the carbon canister solenoid valve is set to the first forced desorption duty cycle to forcibly desorb fuel vapor in the carbon canister; the first forced desorption duty cycle is determined based on the carbon canister load information.

[0028] Optionally, a forced decoupling strategy corresponding to the current state is executed, including:

[0029] When the engine is currently running, a second forced desorption strategy is executed. The second forced desorption strategy includes adjusting the duty cycle of the carbon canister solenoid valve to the second forced desorption duty cycle to forcibly desorb fuel vapor in the carbon canister. The second forced desorption duty cycle is determined based on the actual engine operating information and the carbon canister load information.

[0030] Optionally, after executing the forced decoupling strategy corresponding to the current state, the process further includes:

[0031] When the carbon canister load is less than or equal to the second preset load threshold, exit the carbon canister forced desorption mode; the second preset load threshold is less than the first preset load threshold.

[0032] Optionally, carbon canister desorption operations are performed based on the carbon canister load information, including:

[0033] When the carbon canister load is less than the first preset load threshold, the system enters the normal carbon canister desorption mode and obtains the current status of the engine.

[0034] When the engine is currently being driven by the motor, control the motor to stop driving the engine;

[0035] When the engine is currently running, adjust the duty cycle of the carbon canister solenoid valve to the normal desorption duty cycle to desorb fuel vapor from the carbon canister. The normal desorption duty cycle is determined based on the actual engine operating information and carbon canister load information.

[0036] A vehicle controller for performing the carbon canister desorption method described above for a hybrid vehicle.

[0037] A carbon canister desorption system for a hybrid vehicle includes a carbon canister installed on the hybrid vehicle, a desorption pipeline, a carbon canister solenoid valve, an air flow hydrocarbon sensor, a motor, an engine, a throttle valve installed on the engine intake manifold, and a vehicle controller for performing the carbon canister desorption method of the hybrid vehicle. The carbon canister is connected to the fuel tank of the hybrid vehicle, the motor is connected to the engine, the carbon canister solenoid valve is located on the desorption pipeline, the vehicle controller is connected to the engine, the motor, the carbon canister solenoid valve, and the air flow hydrocarbon sensor, the desorption pipeline is located between the carbon canister and the engine, and the air flow hydrocarbon sensor is located on the carbon canister or on the desorption pipeline.

[0038] A vehicle, including a vehicle controller or a carbon canister desorption system.

[0039] The present invention provides a method, system, vehicle controller, and vehicle for carbon canister desorption in hybrid vehicles. The method includes: after the hybrid vehicle is started, acquiring the SOC value of the hybrid vehicle's power battery; controlling the engine to obtain a preset speed based on the SOC value, thereby controlling the carbon canister solenoid valve of the hybrid vehicle to obtain the desorption flow rate; controlling the airflow hydrocarbon sensor of the hybrid vehicle to acquire carbon canister load information in real time; and performing carbon canister desorption operation based on the carbon canister load information.

[0040] This invention controls the engine to a preset speed based on the State of Charge (SOC) value, thereby controlling the carbon canister solenoid valve of the hybrid vehicle to obtain the desorption flow rate. This allows for real-time acquisition of carbon canister load information via an airflow hydrocarbon sensor, achieving accurate and reliable carbon canister load information regardless of whether the hybrid vehicle is in pure electric or hybrid drive mode. Furthermore, based on the accurate carbon canister load information, different carbon canister desorption operations can be performed to quickly and promptly desorb fuel vapors from the carbon canister, reducing environmental pollution caused by fuel vapor emissions into the atmosphere. Simultaneously, in this invention, the engine is controlled to a preset speed based on the SOC value upon startup, controlling the carbon canister solenoid valve to obtain the desorption flow rate. This enables the collection of carbon canister load information via an airflow hydrocarbon sensor, ensuring high monitoring accuracy while reducing equipment costs compared to using ultrasonic hydrocarbon sensors. Attached Figure Description

[0041] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below 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 effort.

[0042] Figure 1 This is a schematic diagram of the carbon canister desorption system of a hybrid vehicle in one embodiment of the present invention.

[0043] Figure 2 This is a flowchart of a carbon canister desorption method for a hybrid vehicle according to an embodiment of the present invention.

[0044] Figure 3 This is a flowchart of step S200 of the carbon canister desorption method for a hybrid vehicle in one embodiment of the present invention.

[0045] Figure 4 This is a flowchart of step S200 of the carbon canister desorption method for a hybrid vehicle in another embodiment of the present invention.

[0046] Figure 5This is a flowchart of step S400 of the carbon canister desorption method for a hybrid vehicle in another embodiment of the present invention.

[0047] Figure 6 This is a structural block diagram of a vehicle controller in one embodiment of the present invention.

[0048] Figure 7 This is a structural block diagram of a vehicle according to one embodiment of the present invention.

[0049] Figure 8 This is a structural block diagram of a vehicle according to another embodiment of the present invention.

[0050] The reference numerals in the accompanying drawings are as follows:

[0051] 1. Carbon canister; 2. Desorption line; 3. Carbon canister solenoid valve; 4. Air flow hydrocarbon sensor; 5. Motor; 6. Engine; 7. Engine intake manifold; 8. Throttle valve; 9. Vehicle controller; 91. Engine controller; 92. Vehicle controller; 10. Fuel tank; 11. Atmospheric passage; 12. Fuel vapor line; 100. Vehicle; 200. Carbon canister desorption system. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] In one embodiment, such as Figure 1 As shown, the present invention provides a carbon canister desorption system for a hybrid vehicle, including a carbon canister 1 installed on the hybrid vehicle, a desorption pipeline 2, a carbon canister solenoid valve 3, an air flow hydrocarbon sensor 4, a motor 5, an engine 6, a throttle valve 8 installed on the engine intake manifold 7, and a vehicle controller 9 for executing the carbon canister desorption method of the hybrid vehicle in the present invention; the carbon canister 1 is connected to the fuel tank 10 of the hybrid vehicle, the motor 5 is connected to the engine 6, the carbon canister solenoid valve 3 is disposed on the desorption pipeline 2, the vehicle controller 9 is connected to the engine 6, the motor 5, the carbon canister solenoid valve 3, and the air flow hydrocarbon sensor 4, the desorption pipeline 2 is disposed between the carbon canister 1 and the engine 6, and the air flow hydrocarbon sensor 4 is disposed on the carbon canister 1 or the desorption pipeline 2.

[0054] Understandably, the carbon canister desorption system for hybrid vehicles is used in hybrid vehicles (such as plug-in hybrid vehicles), such as... Figure 1 and Figure 6As shown, the vehicle controller 9 may include an engine controller 91 and a vehicle controller 92. The engine controller 91 is electrically connected to the vehicle controller 92. The engine controller 91 is also electrically connected to the carbon canister solenoid valve 3 and the air flow hydrocarbon sensor 4. The motor 5 is connected to the engine 6. The vehicle controller 92 can control the motor 5 to start or control the motor 5 to drive the engine 6.

[0055] Furthermore, the motor 5 can be an integrated starter-generator (ISG) motor 5. The rotor of the motor 5 is connected to the output shaft of the engine 6. When the engine 6 is running, it drives the motor 5 to generate electricity to charge the power battery. The motor 5 can also drive or start the engine 6. When the hybrid vehicle is parked, the power battery can also be charged by an external power source.

[0056] Furthermore, the air flow hydrocarbon sensor 4 can be installed on the carbon canister 1 or on the desorption line 2 between the carbon canister solenoid valve 3 and the carbon canister 1. This allows the carbon canister solenoid valve 3 of the hybrid vehicle to be controlled to obtain the desorption flow after the engine 6 reaches the preset speed (by controlling the carbon canister solenoid valve 3 to open and controlling the outlet pressure of the carbon canister solenoid valve 3 to be less than the inlet pressure). That is, since the engine 6 starts to rotate after reaching the preset speed, and the outlet pressure after the carbon canister solenoid valve opens is less than the inlet pressure, the desorption line 2 opens and the gas flows in the desorption line 2 (the air flow hydrocarbon sensor 4 measures the carbon canister load based on the difference in thermal conductivity between air and fuel vapor. The carbon canister load information can only be measured when there is gas flow. Compared with ultrasonic hydrocarbon sensors, it has lower cost, higher accuracy, and less development work). At this time, the carbon canister load information of the carbon canister 1 can be measured in real time.

[0057] Meanwhile, engine 6 is connected to an intake pipe (i.e., the aforementioned engine intake pipe 7), and throttle valve 8 is installed on the aforementioned engine intake pipe 7. Fuel tank 10 and carbon canister 1 are connected via fuel vapor pipe 12. One end of desorption pipe 2 is connected to carbon canister 1, and the other end of desorption pipe 2 is connected to the engine intake pipe. Carbon canister solenoid valve 3 is installed on desorption pipe 2. Carbon canister 1 is also provided with an atmospheric passage 11 connected to the outside (atmospheric passage 11 is connected to desorption pipe through carbon canister 1). Air flow hydrocarbon sensor 4 is installed on carbon canister 1 or on desorption pipe 2 between carbon canister 1 and carbon canister solenoid valve 3. The fuel tank 10 is used to hold fuel. Fuel vapor generated in fuel tank 10 enters carbon canister 1 through fuel vapor pipe 12 and is adsorbed by activated carbon in carbon canister 1. Preferably, fuel tank 10 is a low-pressure fuel tank 10, but a high-pressure fuel tank 10 can also be used (in which case a fuel tank isolation valve needs to be installed on fuel vapor pipe 12).

[0058] The engine 6 can be either a naturally aspirated engine or a turbocharged engine. If the engine 6 is a naturally aspirated engine, the pressure in its intake manifold 7 will not exceed atmospheric pressure. Since there is no compressor, the pressure throughout the intake manifold 7 is relatively constant. Therefore, as long as one desorption line is connected to the intake manifold, the engine reaches a preset speed, controls the opening of the carbon canister solenoid valve 3, and controls the outlet pressure of the carbon canister solenoid valve 3 to be less than the inlet pressure. This allows gas flow in the desorption line and achieves desorption flow rate. At this time, fuel vapor from the carbon canister 1 flows into the engine intake manifold 7. Therefore, for a naturally aspirated engine, the desorption line 2 only needs to pass through the carbon canister solenoid valve 3 and then connect after the throttle valve 8 of the engine intake manifold 7. That is, the connection point between the desorption line 2 and the engine intake manifold 7 is located between the throttle valve 8 and the engine 6 (e.g., Figure 1 (As shown). However, if the engine 6 is a turbocharged engine, and the turbocharger intervenes under high load, the pressure after the throttle valve 8 in the intake manifold will be higher than the ambient pressure. Therefore, if only one desorption line is connected to the line after the throttle valve 8, as in a naturally aspirated engine, the desorbed gas in the desorption line will not be able to smoothly enter the intake manifold due to pressure limitations. Therefore, the desorption line 2 is split into two paths after the carbon canister solenoid valve 3. The first path connects to the engine intake manifold 7 after the throttle valve 8, and the second path connects to the upstream of the compressor in the engine intake manifold 7 via a venturi tube (not shown). Since the pressure upstream of the compressor is still slightly lower than the ambient pressure, after amplifying this pressure difference via the venturi tube, the airflow in the desorption line 2 can enter the engine intake manifold 7 through the second path (entering the upstream of the compressor in the engine intake manifold 7 via the carbon canister solenoid valve 3). Thus, even under high load conditions, the carbon canister desorption system of the hybrid vehicle can still maintain a certain desorption capacity.

[0059] That is, for both the naturally aspirated engine and the turbocharged engine 6, the carbon canister desorption system of the hybrid vehicle only has one carbon canister solenoid valve 3 on the desorption line 2. However, the naturally aspirated engine's desorption line after the carbon canister solenoid valve 3 is connected to the engine intake manifold 7 only through the connection point after the throttle valve 8 in the engine intake manifold 7. The turbocharged engine's desorption line branches into two paths after the carbon canister solenoid valve 3. The first path, like the naturally aspirated engine, connects to the throttle valve 8 of the engine intake manifold 7, while the second path connects to the upstream of the compressor in the engine intake manifold 7 via a venturi tube.

[0060] Understandably, this hybrid vehicle operates in both pure electric drive mode and hybrid drive mode. When the battery has sufficient charge, such as when the battery's SOC value is greater than or equal to a preset SOC threshold (e.g., 40%), the hybrid vehicle will prioritize operating in pure electric drive mode (where the engine 6 is less likely to start). When the battery's SOC value is less than the preset SOC threshold, the hybrid vehicle will prioritize operating in hybrid drive mode, in which case the engine 6 will start as needed and drive the electric motor 5 to generate electricity.

[0061] In one embodiment, such as Figure 2 As shown, the carbon canister desorption method for the hybrid vehicle includes the following steps S100-S400:

[0062] S100. After the hybrid vehicle is started, the SOC value of the power battery of the hybrid vehicle is obtained. After the hybrid vehicle is started, the SOC value of the power battery can be directly measured and obtained by the vehicle controller 9.

[0063] S200: Control the engine 6 to obtain a preset speed according to the SOC value, so as to control the carbon canister solenoid valve 3 of the hybrid vehicle to obtain the desorption flow rate. Further, controlling the carbon canister solenoid valve 3 of the hybrid vehicle to obtain the desorption flow rate specifically involves: controlling the carbon canister solenoid valve 3 to open, and controlling the outlet pressure of the carbon canister solenoid valve 3 to be less than the inlet pressure. That is, as long as the carbon canister solenoid valve 3 is open, and the outlet pressure of the carbon canister solenoid valve 3 is less than the inlet pressure, the desorption airflow can pass through the carbon canister solenoid valve 3. Therefore, controlling the carbon canister solenoid valve 3 of the hybrid vehicle to obtain the desorption flow rate can be achieved by controlling the carbon canister solenoid valve 3 to open and controlling the outlet pressure of the carbon canister solenoid valve 3 to be less than the inlet pressure. Understandably, if the engine 6 reaches a preset speed, the carbon canister solenoid valve 3 opens and the outlet pressure of the carbon canister solenoid valve is less than the inlet pressure. At this time, the desorption pipeline 2 connecting the engine intake pipe 7 and the carbon canister 1 opens and the gas in the desorption pipeline 2 flows. At this time, the carbon canister load information can be obtained in real time by the air flow hydrocarbon sensor 4 installed on the desorption pipeline 2 or the carbon canister 1. As can be seen from the above, after the engine 6 reaches a preset speed and controls the carbon canister solenoid valve 3 of the hybrid vehicle to obtain the desorption flow, the gas in the desorption pipeline set between the carbon canister 1 and the engine intake pipe 7 will start to flow and enter the engine intake pipe 7. At this time, the air flow hydrocarbon sensor 4 installed on the desorption pipeline 2 or the carbon canister 1 will measure the carbon canister load information in real time based on the difference in thermal conductivity between air and fuel vapor when there is gas flow.

[0064] In one embodiment, such as Figure 3 As shown, in step S200, controlling the engine 6 to obtain a preset speed based on the SOC value includes:

[0065] S201, when the SOC value is greater than or equal to a preset SOC threshold, the vehicle speed of the hybrid vehicle is collected in real time; wherein, the preset SOC threshold can be set according to needs, for example, set to 40%. After the hybrid vehicle starts, its speed can be directly measured and obtained by the vehicle controller 9. Where the vehicle speed is greater than or equal to the preset speed, it is considered that the hybrid vehicle has started and is driving normally; while the vehicle speed is less than the preset speed, it is considered that the hybrid vehicle may not be starting and driving normally at present. For example, if the vehicle is still stationary and the engine 6 is started but not moving, if subsequent operations (such as dragging the engine 6 to rotate) are performed immediately after determining that the SOC value is greater than or equal to the preset SOC threshold, on the one hand, it will cause energy loss, and on the other hand, when the vehicle is starting from a stationary position, suddenly dragging the engine 6 to rotate will cause a poor user experience due to vibration or noise. Therefore, in this embodiment, the vehicle speed of the hybrid vehicle is collected in real time first, and then the vehicle speed is used to determine whether the vehicle is currently driving normally.

[0066] S202, when the vehicle speed is greater than or equal to a preset vehicle speed, the motor 5 of the hybrid vehicle is controlled to drag the engine 6 to a first preset speed. That is, when the SOC value of the power battery is greater than or equal to a preset SOC threshold and the vehicle speed is greater than or equal to a preset vehicle speed (e.g., 35 km / h), the vehicle controller 9 will control the motor 5 to drag the engine 6 to rotate at a first preset speed (e.g., 800 r / min) so that the outlet pressure of the carbon canister solenoid valve is less than the inlet pressure.

[0067] In the above embodiment, when the SOC value is greater than or equal to the preset SOC threshold, it indicates a high SOC value. In this case, the hybrid vehicle will prioritize using the pure electric drive mode. The reason the motor 5 actively drives the engine 6 is that the vehicle controller 9 is less likely to start the engine 6 in pure electric drive mode. However, to prevent fuel vapor in the carbon canister 1 from leaking into the atmosphere due to excessive carbon canister load, continuous monitoring of the carbon canister load is necessary. Therefore, the motor 6 is actively driven to obtain a first preset speed to open the desorption pipeline 2, enabling real-time measurement by the air flow hydrocarbon sensor 4. This embodiment addresses the limitation that the air flow hydrocarbon sensor 4 can only measure the carbon canister load when there is gas flow. When the power battery is in a high SOC state, after the hybrid vehicle starts (a speed greater than the preset speed is considered normal vehicle start-up and driving), the motor 5 drives the engine 6 to obtain the first preset speed to generate a stable and appropriate desorption flow. This allows the air flow hydrocarbon sensor 4 to quickly and accurately manage the carbon canister load, while also avoiding starting the engine 6, which helps save fuel and improves the user experience.

[0068] Further, in step S202, after the engine obtains the first preset speed, the method further includes: setting the engine 6 to disable fuel injection and ignition, simultaneously setting the duty cycle of the carbon canister solenoid valve 3 to the first duty cycle, and setting the throttle valve 8 opening of the engine 6 to a preset opening. That is, after the vehicle controller 9 controls the motor 5 to drive the engine 6 to rotate at the first preset speed (e.g., 800 r / min), and controls the carbon canister solenoid valve 3 of the hybrid vehicle to obtain desorption flow so that the outlet pressure of the carbon canister solenoid valve is less than the inlet pressure, the engine controller 91 will control the engine 6 to disable fuel injection and ignition, and will also set the duty cycle of the carbon canister solenoid valve 3 to the first duty cycle and the throttle valve 8 opening to the preset opening, using the vacuum in the engine intake manifold 7 to provide a stable and appropriate desorption flow, so that the airflow hydrocarbon sensor 4 can quickly and accurately measure the carbon canister load.

[0069] In this embodiment, only after the control motor 5 pulls the engine 6 to a first preset speed can a suitable negative pressure be generated in the engine intake manifold 7 (one working cycle of the engine 6 consists of four strokes: intake, compression, power, and exhaust. Except for the intake stroke, when the intake valve of the engine 6 is open, the intake valve is closed in the other three strokes. During the intake stroke, the intake valve is open, and the cylinder and intake manifold are connected. At this time, the piston in the cylinder moves downward, drawing air from the intake manifold into the cylinder. Therefore, a negative pressure is generated in the intake manifold relative to atmospheric pressure; negative pressure refers to the difference between the pressure in the engine intake manifold 7 and the ambient pressure), thereby enabling a large... Air entering the carbon canister 1 through air passage 11 carries fuel vapor in the carbon canister 1 and then enters the engine intake manifold 7 via desorption line 2. At this time, the vehicle controller 9 (e.g., the engine controller 91 included in the vehicle controller 9) controls the engine 6 to prevent fuel injection and spark plug ignition (the engine 6 is driven by the motor 5 and fuel injection and ignition are simultaneously prohibited; the engine 6 is rotating but not started). Simultaneously, the duty cycle of the carbon canister solenoid valve 3 is set to the first duty cycle (e.g., 10%). The purpose of setting the duty cycle of the carbon canister solenoid valve 3 to the first duty cycle is to obtain a suitable desorption flow rate. Due to the combined effect of the appropriate negative pressure in the engine intake manifold 7 and the duty cycle of the carbon canister solenoid valve 3, a suitable desorption flow rate is obtained. If the desorption flow rate is too large, the desorbed airflow will be directly discharged into the environment in large quantities from the intake manifold to the cylinder and then to the exhaust manifold in the engine 6, resulting in excessive hydrocarbon emissions from the engine 6. If the desorption flow rate is too small, it can be considered that the desorption line 2 is not open, that is, the gas in the desorption line 2 is not flowing smoothly. Therefore, the air flow hydrocarbon sensor 4 cannot accurately measure the carbon canister load. Understandably, while setting the duty cycle of the carbon canister solenoid valve 3 installed on the desorption line 2 to the first duty cycle, it is also necessary to set the throttle valve 8 of the engine 6 to a preset opening (such as 3%). The purpose of setting the throttle valve 8 of the engine 6 to a preset opening is that the opening of the throttle valve 8 and the engine speed of the engine 6 together determine the negative pressure of the intake manifold. The purpose of setting the throttle valve 8 to a preset opening is also to control the negative pressure of the engine intake manifold 7 within a suitable range. In this embodiment, after the above operations are completed, the engine intake manifold 7 is under negative pressure. At this time, air enters the carbon canister 1 through the atmospheric passage 11, desorbing the fuel vapor adsorbed by the activated carbon in the carbon canister 1. The vapor is then drawn into the desorption pipe 2, enters the engine intake manifold 7 through the carbon canister solenoid valve 3, enters the engine cylinder 6 through the engine intake valve, and then enters the exhaust manifold through the engine exhaust valve. In this embodiment, the engine 6 is only driven by the motor 5 to rotate at a first preset speed without ignition or fuel injection. Therefore, this embodiment can ensure a stable and appropriate amount of desorbed airflow through the airflow hydrocarbon sensor 4 without starting the engine 6. This allows the carbon canister load to be measured quickly and accurately by the airflow hydrocarbon sensor 4, which is beneficial for saving fuel and improving the user experience.

[0070] In one embodiment, such as Figure 4 As shown, in step S200, controlling the engine 6 to obtain a preset speed based on the SOC value includes:

[0071] S203, when the SOC value is less than the preset SOC threshold, the system detects in real time whether the engine 6 is started; that is, after the hybrid vehicle starts driving, when the SOC value is less than the preset SOC threshold, the hybrid vehicle will prioritize using the hybrid drive mode. At this time, the vehicle controller 92 will control the engine 6 to start if necessary. Therefore, in this embodiment, the vehicle controller 9 will no longer actively control the motor 5 to drive the engine 6, but will first detect whether the engine 6 is started, so as to control the desorption pipe 2 to open when the engine 6 starts. This can save the hybrid vehicle's power (driving the engine 6 requires power) and does not affect the user's driving experience.

[0072] S204, when the engine 6 is detected to be starting, the engine speed is controlled to be adjusted to a second preset speed (e.g., 1200 r / min), where the second preset speed is greater than or equal to the first preset speed. Understandably, since in the above embodiment, the first preset speed is driven by the motor 5 to rotate the engine 6, it only needs to be sufficient to allow gas flow in the desorption pipe 2; it does not need to be too high, otherwise it would increase power consumption. The second preset speed is the operating speed of the engine 6 after it has started normally. Based on considerations of NVH (noise, vibration, and harshness) and engine 6 efficiency, the second preset speed in this embodiment is greater than the first preset speed.

[0073] Furthermore, in step S204, after the engine obtains the second preset speed, the method further includes:

[0074] Control the torque output of engine 6 to a preset torque (e.g., 15 Nm); in this step, the purpose of setting the preset torque is to ensure that engine 6 runs smoothly and outputs a certain amount of power to improve the efficiency of engine 6 (understandably, when the SOC value of the power battery is greater than or equal to the preset SOC threshold, motor 5 drives engine 6 to rotate. At this time, engine 6 does not output torque, but instead absorbs the torque of ISG, that is, engine 6 does negative work, so there is no need to set the output torque of engine 6).

[0075] When the engine 6 is warmed up to the first preset temperature, the duty cycle of the canister purge solenoid valve 3 is set to the second duty cycle. The first preset temperature can be set as needed, for example, to 40°C. Understandably, engine warm-up is a prerequisite for the canister purge solenoid valve 3 to open. If the canister purge solenoid valve 3 is suddenly opened before the engine 6 is warmed up, the sudden influx of airflow may cause the engine 6 to suddenly shut down. Therefore, it is necessary to wait for the engine 6 to warm up to the first preset temperature before setting the duty cycle of the canister purge solenoid valve 3 to the second duty cycle (e.g., 15%) via the engine controller 91. This ensures that, while maintaining normal engine operation, a stable and appropriate amount of desorbed airflow passes through the airflow hydrocarbon sensor 4, thereby quickly and accurately measuring the canister purge load information.

[0076] S300: Control the air flow hydrocarbon sensor of the hybrid vehicle to obtain carbon canister load information in real time; that is, after controlling the engine 6 to obtain a preset speed, so that the outlet pressure of the carbon canister solenoid valve is less than the inlet pressure, thereby opening the desorption pipeline 2 to obtain a stable and appropriate desorption flow (that is, the flow rate of gas in the desorption pipeline 2), the carbon canister load information can be quickly and accurately measured by the air flow hydrocarbon sensor 4. In this embodiment, the measurement accuracy of carbon canister desorption information is high and the cost is low. Moreover, the air flow hydrocarbon sensor 4 is installed on the desorption pipeline 2 or the carbon canister 1, which is convenient to arrange.

[0077] S400. Perform carbon canister desorption operation based on the carbon canister load information. Specifically, after receiving the carbon canister load information (i.e., the voltage signal measured in real time by the air flow hydrocarbon sensor 4) from the air flow hydrocarbon sensor 4, the engine controller 91 calculates the carbon canister load based on the carbon canister load information, and then performs carbon canister desorption operation based on the calculated carbon canister load.

[0078] In this embodiment of the invention, the engine 6 can be controlled to obtain a preset speed by controlling the SOC value, thereby controlling the carbon canister solenoid valve 3 of the hybrid vehicle to obtain the desorption flow rate. This allows the carbon canister load information to be acquired in real time via the air flow hydrocarbon sensor 4, achieving the goal of accurately and reliably acquiring carbon canister load information regardless of whether the hybrid vehicle is in pure electric drive mode or hybrid drive mode. Furthermore, based on the accurate carbon canister load information measured above, different carbon canister desorption operations can be performed to quickly and timely desorb fuel vapor from the carbon canister 1, reducing environmental pollution caused by fuel vapor emissions into the atmosphere. Simultaneously, in this invention, after the hybrid vehicle starts, the engine 6 is controlled to obtain a preset speed based on the SOC value, thereby controlling the carbon canister solenoid valve 3 of the hybrid vehicle to obtain the desorption flow rate. This allows the carbon canister load information to be collected via the air flow hydrocarbon sensor 4. While ensuring high monitoring accuracy, this also reduces equipment costs compared to ultrasonic hydrocarbon sensors (ultrasonic hydrocarbon sensors measure carbon canister load information based on the different propagation speeds of sound waves in air and fuel vapor, and can measure carbon canister load information regardless of the presence or absence of gas flow, but are expensive).

[0079] In one embodiment, step S400, namely the carbon canister desorption operation based on the carbon canister load information, includes:

[0080] S401, when it is determined that the carbon canister load is greater than or equal to a first preset load threshold, the current state of engine 6 is obtained, and the carbon canister 1 forced desorption mode is entered to execute the forced desorption strategy corresponding to the current state. The first preset load threshold can be set according to requirements, for example, it can be set to 90%. When the carbon canister load is determined to be greater than or equal to the first preset load threshold based on the carbon canister load information, it indicates that the carbon canister load is currently too high. At this time, there is a high possibility that excessive fuel vapor in the carbon canister 1 will be released into the atmosphere and cause environmental pollution due to its inability to desorb in time. Therefore, it is necessary to enter the carbon canister 1 forced desorption mode to execute the forced desorption strategy corresponding to the current state. Specifically, the engine controller 91 will notify the vehicle controller 92 to activate the carbon canister 1 forced desorption mode. At this time, the vehicle controller 92 sets the engine speed and torque of engine 6 to an appropriate level. Understandably, the specific range of the engine speed and torque settings depends on the vehicle's power demand on engine 6 and the intake manifold pressure. The purpose of these settings is to ensure that the pressure in the engine intake manifold 7 is less than or equal to 0.8 times the atmospheric pressure, while simultaneously meeting the vehicle's power demand on engine 6 as much as possible. For example, the engine speed can be set to 1200–4000 r / min and the torque to 15–100 Nm. This ensures that the engine 6 meets the power requirements while optimizing its operating conditions for desorption of fuel vapor from the carbon canister 1 using a forced desorption strategy. In this embodiment, different forced desorption strategies can be formulated based on the current state of the engine 6 to quickly desorb fuel vapor from the carbon canister 1, preventing fuel vapor from escaping into the atmosphere and causing environmental pollution.

[0081] In one specific embodiment, step S400, executing the forced de-attachment strategy corresponding to the current state, includes:

[0082] When the current state of the engine 6 is that it is driven by the motor 5, a first forced decoupling strategy is executed, the first forced decoupling strategy including:

[0083] After controlling the fuel injector injection and spark plug ignition of engine 6, and setting the duty cycle of the carbon canister solenoid valve 3 to 0%, engine 6 is started. That is, when the carbon canister load is greater than or equal to the first preset load threshold, it is considered that the carbon canister load is too high, and there is a risk that the fuel vapor in the carbon canister 1 will leak into the atmosphere. Therefore, forced desorption is required. At this time, the vehicle controller 92 will activate the carbon canister 1 forced desorption mode, and set the engine speed and torque of engine 6 to an appropriate level so that the operating conditions of engine 6 are most conducive to carbon canister desorption, and finally achieve rapid desorption of carbon canister 1. At this time, if The engine 6 is driven by the motor 5 (that is, the SOC value of the power battery is greater than or equal to the preset SOC threshold, and the carbon canister load information is monitored in real time by opening the desorption line 2 when the engine 6 is driven by the motor 5). At this time, the motor 5 has already driven the engine 6 to a higher speed, so it is only necessary to control the fuel injector of the engine 6 and the spark plug ignition (at the same time, the duty cycle of the carbon canister solenoid valve 3 needs to be set to 0%, and the carbon canister solenoid valve 3 does not open before the engine is warmed up to the second preset temperature) to start the engine 6.

[0084] When the engine 6 is warmed up to the second preset temperature, the duty cycle of the carbon canister solenoid valve 3 is set to the first forced desorption duty cycle to forcibly desorb fuel vapor from the carbon canister 1. The first forced desorption duty cycle is determined based on the carbon canister load information. When the engine 6 is first started, the coolant temperature is low. If the carbon canister solenoid valve 3 is opened at this time to forcibly desorb the carbon canister 1, it will affect the stable operation of the engine 6. Moreover, the three-way catalytic converter in the exhaust pipe is not sufficiently heated and cannot oxidize hydrocarbons into harmless gases. Therefore, warm-up is required. After the engine 6 coolant temperature rises to the second preset temperature (wherein, the second preset temperature can be set according to needs, for example, 40°C, and the second preset temperature can be the same as or different from the first preset temperature), the carbon canister solenoid valve 3 can be opened to desorb the carbon canister, introducing the fuel vapor from the carbon canister 1 into the cylinder for combustion and then into the exhaust pipe.

[0085] In another specific embodiment, step S400, executing the forced de-attachment strategy corresponding to the current state, includes:

[0086] When the current state of the engine 6 is started, a second forced desorption strategy is executed. The second forced desorption strategy includes: adjusting the duty cycle of the carbon canister solenoid valve 3 to a second forced desorption duty cycle to forcibly desorb fuel vapor in the carbon canister 1; the second forced desorption duty cycle is determined based on the actual operating information of the engine 6 and the carbon canister load information. That is, when the carbon canister load is greater than or equal to the first preset load threshold, forced desorption is required. If the engine 6 has started (that is, the power battery SOC value is less than the preset SOC threshold, and the carbon canister load information is obtained by opening the desorption pipeline 2 when the engine 6 is started, and the duty cycle of the carbon canister solenoid valve 3 is set to the second duty cycle as described in step S200 and is monitored in real time by the air flow hydrocarbon sensor 4), since the duty cycle of the carbon canister solenoid valve 3 is the second duty cycle, but this second duty cycle (e.g., 15%) is a relatively small value, in order to desorb the carbon canister 1 as soon as possible and ensure the smooth operation of the engine 6, it is necessary to adjust the duty cycle of the carbon canister solenoid valve 3 according to the actual situation. Specifically, based on the engine speed, intake air volume, etc. of the engine 6, and forming a closed-loop control with the front oxygen sensor in the exhaust pipe, the carbon canister desorption flow rate is increased as much as possible without affecting the smooth operation of the engine 6, that is, the duty cycle of the carbon canister solenoid valve 3 is increased as much as possible while ensuring the power requirements of the engine 6.

[0087] In one embodiment, after step S400, that is, after executing the forced desorption strategy corresponding to the current state, the method further includes: exiting the forced desorption mode of carbon canister 1 when the carbon canister load is less than or equal to a second preset load threshold; the second preset load threshold is less than the first preset load threshold. That is, after performing carbon canister desorption on carbon canister 1 using the forced desorption strategy, carbon canister 1 can be quickly desorbed until the carbon canister load is less than or equal to the second preset load threshold (e.g., 70%), at which point the vehicle controller 92 will exit the forced desorption mode of carbon canister 1 and return to the normal desorption mode of carbon canister 1. Specifically, as fuel vapor in the carbon canister 1 is continuously desorbed, the carbon canister load calculated by the engine controller 91 through the air flow hydrocarbon sensor 4 also decreases continuously until the carbon canister load is less than or equal to the second preset load threshold. This indicates that the carbon canister 1 has sufficient capacity to adsorb fuel vapor from the fuel tank 10, which can largely ensure that fuel vapor will not leak into the atmosphere during the period from the current use to the next use of the vehicle. Since the higher the carbon canister load, the easier it is to desorb the carbon canister, after the carbon canister load is greater than or equal to the first preset load threshold, the carbon canister load can be reduced from the first preset load threshold to the second preset load threshold in a short time through the carbon canister 1 forced desorption mode. After that, the carbon canister 1 forced desorption mode is exited. This can avoid fuel vapor being emitted into the atmosphere and also shorten the duration of the carbon canister 1 forced desorption mode, reducing the impact of the carbon canister 1 forced desorption mode on the vehicle driving experience (in the carbon canister 1 forced desorption mode, setting the speed, torque range, etc. will impose some restrictions on the operation of the engine 6, which may affect the driving experience in some special cases, such as when the vehicle has a high power or high load demand on the engine 6). Understandably, after the vehicle controller 92 exits the forced desorption mode of the carbon canister 1 and returns to the previous normal desorption mode, the normal driving of the vehicle is given priority. At this time, the engine controller 91 keeps the engine 6 running or shut down according to the command of the vehicle controller 92.

[0088] In one embodiment, such as Figure 5 As shown, step S400, namely the carbon canister desorption operation based on the carbon canister load information, includes:

[0089] S402, when the carbon canister load is less than a first preset load threshold, the system enters the normal desorption mode for carbon canister 1 and acquires the current status of engine 6. The first preset load threshold can be set as needed, for example, to 90%. When the carbon canister load is determined to be less than the first preset load threshold based on the carbon canister load information, it indicates that the current carbon canister load is not too high, and an accident causing environmental pollution due to fuel vapor not being desorbed in time is unlikely. Therefore, it is not necessary to enter the forced desorption mode for carbon canister 1 at this time; instead, the system enters the normal desorption mode for carbon canister 1. The normal desorption mode for carbon canister 1 is any other driving mode of the vehicle besides the normal desorption mode for carbon canister 1.

[0090] S403, when the current state of the engine 6 is driven by the motor 5, the motor 5 is controlled to stop driving the engine 6; that is, when the carbon canister load is determined to be less than the first preset load threshold based on the carbon canister load information, if the current state of the engine 6 is driven by the motor 5 (that is, at this time the power battery SOC value is greater than or equal to the preset SOC threshold, and the carbon canister load information is obtained by opening the desorption pipeline 2 while the engine 6 is being driven by the motor 5, and then monitoring it in real time by the air flow hydrocarbon sensor 4), the vehicle controller 92 will instruct the motor 5 to stop driving the engine 6, the engine controller 91 will return to the standby state, and the duty cycle of the carbon canister solenoid valve 3 and the opening of the throttle valve 8 will be set to the default values ​​(for example, the default values ​​of the duty cycle of the carbon canister solenoid valve 3 and the opening of the throttle valve 8 are both 0). That is, in the normal desorption mode of the carbon canister 1, when the current state of the engine 6 is driven by the motor 5, there is no need to perform carbon canister desorption.

[0091] S404, when the current state of the engine 6 is started, the duty cycle of the carbon canister solenoid valve 3 is adjusted to the normal desorption duty cycle to normally desorb fuel vapor in the carbon canister 1; the normal desorption duty cycle is determined according to the actual operating information of the engine 6 and the carbon canister load information. That is, when the carbon canister load is determined to be less than the first preset load threshold according to the carbon canister load information, if the current state of the engine 6 is started (that is, at this time the power battery SOC value is less than the preset SOC threshold, the carbon canister load information is that the desorption pipeline 2 is opened when the engine 6 is started, at this time the duty cycle of the carbon canister solenoid valve 3 will be set to the second duty cycle as described in step S200 and monitored in real time by the air flow hydrocarbon sensor 4), then the vehicle controller 92 returns to the normal mode to control the vehicle according to the power demand of the vehicle driving, and sets the target speed and torque of the engine 6 according to the actual demand. That is, in the normal desorption mode of the carbon canister 1, the speed and torque range are not limited because carbon canister desorption is required. Instead, the speed and torque of the engine 6 are adjusted according to the power demand of the vehicle on the engine 6. At this time, the control of the carbon canister solenoid valve 3 by the engine controller 91 also returns to the normal mode. The duty cycle of the carbon canister solenoid valve 3 can be adjusted according to the actual situation. Here, the duty cycle is adjusted according to the actual situation, which is relative to the carbon canister solenoid valve 3 being set to the second duty cycle in step S200. When returning to the normal carbon canister desorption mode, the duty cycle of the carbon canister solenoid valve 3 is no longer fixed at the second duty cycle. Instead, the carbon canister desorption strategy of the engine controller 91 takes over. That is, based on the comprehensive consideration of the engine speed, intake air volume, power demand, etc., and forming a closed-loop control with the front oxygen sensor in the exhaust pipe, the carbon canister desorption flow is increased as much as possible without affecting the stable operation of the engine 6. That is, the normal desorption duty cycle of the carbon canister solenoid valve 3 is increased as much as possible.

[0092] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0093] The present invention also provides a vehicle controller 9, which is used to execute the carbon canister desorption method for the hybrid vehicle described above. The specific configuration of the vehicle controller 9 of the present invention corresponds one-to-one with the carbon canister desorption method for the hybrid vehicle described above, and will not be repeated here. Figure 6 As shown, the vehicle controller 9 may include an engine controller 91 and a vehicle controller 92; in a specific embodiment, as Figure 1As shown, the engine controller 91 is electrically connected to the vehicle controller 92, and is also electrically connected to the carbon canister solenoid valve 3 and the air flow hydrocarbon sensor 4. The motor 5 is connected to the engine 6. The vehicle controller 92 can control the motor 5 to start or control the motor 5 to drive the engine 6. Each module in the vehicle controller 9 can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the vehicle controller 9 in hardware form or independently of the computer device, or stored in the memory of the computer device in software form, so that the vehicle controller 9 can call and execute the corresponding operations of each module.

[0094] like Figure 1 As shown, the present invention also provides a carbon canister desorption system for a hybrid vehicle, including a carbon canister 1 installed on the hybrid vehicle, a desorption pipeline 2, a carbon canister solenoid valve 3, an air flow hydrocarbon sensor 4, a motor 5, an engine 6, a throttle valve 8 installed on the engine intake manifold 7, and a vehicle controller 9 for executing the carbon canister desorption method of the hybrid vehicle in the present invention; the carbon canister 1 is connected to the fuel tank 10 of the hybrid vehicle, the motor 5 is connected to the engine 6, the carbon canister solenoid valve 3 is disposed on the desorption pipeline 2, the vehicle controller 9 is connected to the engine 6, the motor 5, the carbon canister solenoid valve 3, and the air flow hydrocarbon sensor 4, the desorption pipeline 2 is disposed between the carbon canister 1 and the engine 6, and the air flow hydrocarbon sensor 4 is disposed on the carbon canister 1 or the desorption pipeline 2.

[0095] Understandably, the carbon canister desorption system for hybrid vehicles is used in hybrid vehicles (such as plug-in hybrid vehicles), such as... Figure 1 and Figure 6 As shown, the vehicle controller 9 may include an engine controller 91 and a vehicle controller 92. The engine controller 91 is electrically connected to the vehicle controller 92. The engine controller 91 is also electrically connected to the carbon canister solenoid valve 3 and the air flow hydrocarbon sensor 4. The motor 5 is connected to the engine 6. The vehicle controller 92 can control the motor 5 to start or control the motor 5 to drive the engine 6.

[0096] Furthermore, the motor 5 can be an integrated starter-generator (ISG) motor 5. The rotor of the motor 5 is connected to the output shaft of the engine 6. When the engine 6 is running, it drives the motor 5 to generate electricity to charge the power battery. The motor 5 can also drive or start the engine 6. When the hybrid vehicle is parked, the power battery can also be charged by an external power source.

[0097] Furthermore, the air flow hydrocarbon sensor 4 can be installed on the carbon canister 1 or on the desorption line 2 between the carbon canister solenoid valve 3 and the carbon canister 1. This allows the carbon canister solenoid valve 3 of the hybrid vehicle to be controlled to obtain the desorption flow after the engine 6 reaches the preset speed (by controlling the carbon canister solenoid valve 3 to open and controlling the outlet pressure of the carbon canister solenoid valve 3 to be less than the inlet pressure). That is, since the engine 6 starts to rotate after reaching the preset speed, and the outlet pressure after the carbon canister solenoid valve opens is less than the inlet pressure, the desorption line 2 opens and the gas flows in the desorption line 2 (the air flow hydrocarbon sensor 4 measures the carbon canister load based on the difference in thermal conductivity between air and fuel vapor. The carbon canister load information can only be measured when there is gas flow. Compared with ultrasonic hydrocarbon sensors, it has lower cost, higher accuracy, and less development work). At this time, the carbon canister load information of the carbon canister 1 can be measured in real time.

[0098] Meanwhile, engine 6 is connected to an intake pipe (i.e., the aforementioned engine intake pipe 7), and throttle valve 8 is installed on the aforementioned engine intake pipe 7. Fuel tank 10 and carbon canister 1 are connected via fuel vapor pipe 12. One end of desorption pipe 2 is connected to carbon canister 1, and the other end of desorption pipe 2 is connected to the engine intake pipe. Carbon canister solenoid valve 3 is installed on desorption pipe 2. Carbon canister 1 is also provided with an atmospheric passage 11 connected to the outside (atmospheric passage 11 is connected to desorption pipe through carbon canister 1). Air flow hydrocarbon sensor 4 is installed on carbon canister 1 or on desorption pipe 2 between carbon canister 1 and carbon canister solenoid valve 3. The fuel tank 10 is used to hold fuel. Fuel vapor generated in fuel tank 10 enters carbon canister 1 through fuel vapor pipe 12 and is adsorbed by activated carbon in carbon canister 1. Preferably, fuel tank 10 is a low-pressure fuel tank 10, but a high-pressure fuel tank 10 can also be used (in which case a fuel tank isolation valve needs to be installed on fuel vapor pipe 12).

[0099] The engine 6 can be either a naturally aspirated engine or a turbocharged engine. If the engine 6 is a naturally aspirated engine, the pressure in its intake manifold 7 will not exceed atmospheric pressure. Since there is no compressor, the pressure throughout the intake manifold 7 is relatively constant. Therefore, as long as one desorption line is connected to the intake manifold, the engine reaches a preset speed, controls the opening of the carbon canister solenoid valve 3, and controls the outlet pressure of the carbon canister solenoid valve 3 to be less than the inlet pressure. This allows gas flow in the desorption line and achieves desorption flow rate. At this time, fuel vapor from the carbon canister 1 flows into the engine intake manifold 7. Therefore, for a naturally aspirated engine, the desorption line 2 only needs to pass through the carbon canister solenoid valve 3 and then connect after the throttle valve 8 of the engine intake manifold 7. That is, the connection point between the desorption line 2 and the engine intake manifold 7 is located between the throttle valve 8 and the engine 6 (e.g., Figure 1(As shown). However, if the engine 6 is a turbocharged engine, and the turbocharger intervenes under high load, the pressure after the throttle valve 8 in the intake manifold will be higher than the ambient pressure. Therefore, if only one desorption line is connected to the line after the throttle valve 8, as in a naturally aspirated engine, the desorbed gas in the desorption line will not be able to smoothly enter the intake manifold due to pressure limitations. Therefore, the desorption line 2 is split into two paths after the carbon canister solenoid valve 3. The first path connects to the engine intake manifold 7 after the throttle valve 8, and the second path connects to the upstream of the compressor in the engine intake manifold 7 via a venturi tube (not shown). Since the pressure upstream of the compressor is still slightly lower than the ambient pressure, after amplifying this pressure difference via the venturi tube, the airflow in the desorption line 2 can enter the engine intake manifold 7 through the second path (entering the upstream of the compressor in the engine intake manifold 7 via the carbon canister solenoid valve 3). Thus, even under high load conditions, the carbon canister desorption system of the hybrid vehicle can still maintain a certain desorption capacity.

[0100] That is, for both the naturally aspirated engine and the turbocharged engine 6, the carbon canister desorption system of the hybrid vehicle only has one carbon canister solenoid valve 3 on the desorption line 2. However, the naturally aspirated engine's desorption line after the carbon canister solenoid valve 3 is connected to the engine intake manifold 7 only through the connection point after the throttle valve 8 in the engine intake manifold 7. The turbocharged engine's desorption line branches into two paths after the carbon canister solenoid valve 3. The first path, like the naturally aspirated engine, connects to the throttle valve 8 of the engine intake manifold 7, while the second path connects to the upstream of the compressor in the engine intake manifold 7 via a venturi tube.

[0101] The carbon canister desorption system of the hybrid vehicle of the present invention can control the engine 6 to obtain a preset speed through the SOC value, thereby controlling the carbon canister solenoid valve 3 of the hybrid vehicle to obtain the desorption flow rate. In this way, the carbon canister load information is obtained in real time through the air flow hydrocarbon sensor 4, so as to achieve the purpose of accurately and reliably obtaining carbon canister load information regardless of whether the hybrid vehicle is driving in pure electric drive mode or hybrid drive mode. Furthermore, based on the accurate carbon canister load information obtained above, different carbon canister desorption operations can be performed to quickly and timely desorb fuel vapor in the carbon canister 1, reducing environmental pollution caused by fuel vapor emission into the atmosphere. Meanwhile, in this invention, after the hybrid vehicle starts, it controls the engine 6 to obtain a preset speed based on the SOC value, so as to control the carbon canister solenoid valve 3 of the hybrid vehicle to obtain the desorption flow. In this way, the carbon canister load information can be collected through the air flow hydrocarbon sensor 4. While ensuring high monitoring accuracy, it also reduces equipment costs compared to ultrasonic hydrocarbon sensors (ultrasonic hydrocarbon sensors measure carbon canister load information based on the different propagation speeds of sound waves in air and fuel vapor. They can measure carbon canister load information regardless of whether there is gas flow, but they are expensive).

[0102] In one embodiment, such as Figure 7 As shown, the present invention also provides a vehicle including the vehicle controller 9 described above.

[0103] In another embodiment, such as Figure 8 As shown, the present invention provides a vehicle including the above-described carbon canister desorption system.

[0104] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for desorbing carbon canisters in a hybrid vehicle, characterized in that, include: After the hybrid vehicle is started, the SOC value of the power battery of the hybrid vehicle is obtained; The engine is controlled to obtain a preset speed based on the SOC value, so as to control the carbon canister solenoid valve of the hybrid vehicle to obtain the desorption flow rate. The airflow of the hybrid vehicle is controlled by a hydrocarbon sensor that acquires carbon canister load information in real time. Perform carbon canister desorption operation based on the carbon canister load information; The step of controlling the engine to obtain a preset speed based on the SOC value includes: when the SOC value is greater than or equal to a preset SOC threshold, collecting the vehicle speed of the hybrid vehicle in real time; when the vehicle speed is greater than or equal to a preset vehicle speed, controlling the electric motor of the hybrid vehicle to drag the engine to a first preset speed; when the SOC value is less than the preset SOC threshold, detecting whether the engine is starting in real time; and when the engine is detected to be starting, controlling the engine speed to adjust to a second preset speed, wherein the second preset speed is greater than or equal to the first preset speed. The carbon canister desorption operation based on the carbon canister load information includes: when the carbon canister load is greater than or equal to a first preset load threshold, obtaining the current state of the engine and entering the carbon canister forced desorption mode to execute the forced desorption strategy corresponding to the current state; when the current state of the engine is motor driven, executing the first forced desorption strategy; and when the current state of the engine is started, executing the second forced desorption strategy.

2. The carbon canister desorption method according to claim 1, characterized in that, After the engine obtains the first preset speed, it further includes: The engine is set to disable fuel injection and ignition, the duty cycle of the carbon canister solenoid valve is set to the first duty cycle, and the throttle opening of the engine is set to a preset opening.

3. The carbon canister desorption method according to claim 1, characterized in that, After the engine obtains the second preset speed, it further includes: Control the engine torque output to a preset torque; When the engine is warmed up to the first preset temperature, the duty cycle of the carbon canister solenoid valve is set to the second duty cycle.

4. The carbon canister desorption method according to claim 1, characterized in that, The solenoid valve controlling the carbon canister of the hybrid vehicle obtains the desorption flow specifically as follows: The solenoid valve of the carbon canister is controlled to open, and the outlet pressure of the solenoid valve is controlled to be less than the inlet pressure.

5. The carbon canister desorption method as described in claim 1, characterized in that, The first forced desorption strategy includes: After controlling the engine's fuel injectors to inject fuel and the spark plugs to ignite, and setting the duty cycle of the carbon canister solenoid valve to 0%, the engine is started. When the engine is warmed up to the second preset temperature, the duty cycle of the carbon canister solenoid valve is set to the first forced desorption duty cycle to forcibly desorb fuel vapor from the carbon canister; the first forced desorption duty cycle is determined based on the carbon canister load information.

6. The carbon canister desorption method as described in claim 1, characterized in that, The second forced desorption strategy includes: adjusting the duty cycle of the carbon canister solenoid valve to a second forced desorption duty cycle to forcibly desorb fuel vapor from the carbon canister; the second forced desorption duty cycle is determined based on the actual engine operating information and the carbon canister load information.

7. The carbon canister desorption method as described in claim 1, characterized in that, After executing the forced decoupling strategy corresponding to the current state, the method further includes: When the carbon canister load is less than or equal to the second preset load threshold, the carbon canister forced desorption mode is exited; the second preset load threshold is less than the first preset load threshold.

8. The carbon canister desorption method as described in claim 1, characterized in that, The carbon canister desorption operation based on the carbon canister load information includes: When the carbon canister load is less than the first preset load threshold, the system enters the normal carbon canister desorption mode and obtains the current status of the engine. When the current state of the engine is that it is driven by a motor, control the motor to stop driving the engine; When the engine is currently running, the duty cycle of the carbon canister solenoid valve is adjusted to the normal desorption duty cycle to desorb fuel vapor from the carbon canister. The normal desorption duty cycle is determined based on the actual engine operating information and the carbon canister load information.

9. A vehicle controller, characterized in that, The vehicle controller is used to execute the carbon canister desorption method for the hybrid vehicle according to any one of claims 1 to 8.

10. A carbon canister desorption system, characterized in that, The device includes a carbon canister, a desorption line, a carbon canister solenoid valve, an air flow hydrocarbon sensor, a motor, an engine, a throttle valve mounted on the engine intake manifold, and a vehicle controller for performing the carbon canister desorption method of the hybrid vehicle according to any one of claims 1 to 8; the carbon canister is connected to the fuel tank of the hybrid vehicle, the motor is connected to the engine, the carbon canister solenoid valve is disposed on the desorption line, the vehicle controller is connected to the engine, the motor, the carbon canister solenoid valve, and the air flow hydrocarbon sensor, the desorption line is disposed between the carbon canister and the engine, and the air flow hydrocarbon sensor is disposed on the carbon canister or on the desorption line.

11. A vehicle, characterized in that, Includes the vehicle controller as described in claim 9, or includes the carbon canister desorption system as described in claim 10.

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