Method and device for controlling pressure of urea pump of hybrid vehicle and electronic equipment

Abstract

The invention discloses a urea pump pressure control method and device of a hybrid vehicle and electronic equipment, and the method comprises the steps that after an engine stops, the aftertreatment temperature of the engine is obtained; determining whether to control the urea pump to release pressure or not according to the post-treatment temperature; when the urea pump does not release pressure, the charge state of the power battery and the whole vehicle demand power of the hybrid vehicle are obtained; and the pressure of the urea pump is adjusted according to the charge state and the whole vehicle demand power, so that the pressure of the urea pump is lower than the injection pressure of the urea pump in the engine running state. Certain urea pump pressure is maintained in the shutdown process of an engine, the leakage rate of a urea nozzle is reduced, and urea is prevented from being crystallized in a mixer; meanwhile, the urea injection system can reach injection pressure as soon as possible after the engine is started, and tail gas emission is prevented from exceeding the standard.

Description

Technical Field

[0001] The present invention relates to the technical field of hybrid control, and in particular to a urea pump pressure control method, a control device and an electronic device for a hybrid vehicle. Background Art

[0002] The diesel hybrid system is a power system that combines a diesel engine and an electric motor. During vehicle operation, the vehicle controller (HCU) controls the diesel engine to stop and start according to the vehicle status. For example, when the power battery is high and the vehicle power demand is low, the vehicle power demand is small and the diesel engine is controlled to stop.

[0003] Diesel engines are usually equipped with a urea injection system, which is used to inject urea during post-treatment to reduce nitrogen oxide emissions. The urea injection system includes a urea pump, a urea tank, a urea nozzle and connecting pipes. After the engine is running, when the post-treatment temperature is greater than a certain value, the urea pump will draw from the urea tank and maintain a certain pressure (for example, 9 bar), and transport it to the urea nozzle through the pipeline. The urea nozzle performs injection according to the post-treatment temperature and the original nitrogen oxide emission conditions. Since the urea nozzle is installed before the selective catalytic reduction system (Selective Catalytic Reduction, referred to as SCR), there will be partial leakage when urea is not injected.

[0004] In diesel hybrid vehicles, the engine has many start-stop conditions. After the engine is shut down, the urea pump releases pressure; when the engine is restarted, the urea pump needs to successfully build up pressure according to temperature conditions. However, since it usually takes 20 to 30 seconds for the urea pump to build up pressure, the urea injection system cannot inject urea during this time, which can easily lead to excessive nitrogen oxide emissions and affect the exhaust gas treatment effect. Summary of the invention

[0005] The present invention provides a urea pump pressure control method, a control device and an electronic device for a hybrid vehicle, so as to solve the existing problem that under the condition of frequent engine start-stop, the pressure building time after urea spraying and pressure relief is long, urea cannot be sprayed during the pressure building period, and nitrogen oxide emissions exceed the standard. By controlling the urea pump not to release the pressure after the engine stops and lowering the urea pump pressure at the same time, the pressure building time of the urea pump is shortened and the urea leakage is reduced.

[0006] According to one aspect of the present invention, a urea pump pressure control method for a hybrid vehicle is provided, the hybrid vehicle comprising an engine and a power battery, the method comprising: after the engine is stopped, obtaining a post-processing temperature of the engine; determining whether to control the urea pump to release pressure according to the post-processing temperature; when the urea pump does not release pressure, obtaining a state of charge of the power battery and a whole vehicle power requirement of the hybrid vehicle; adjusting the urea pump pressure according to the state of charge and the whole vehicle power requirement; wherein the urea pump pressure is lower than the injection pressure of the urea pump when the engine is running.

[0007] Optionally, adjusting the urea pump pressure according to the state of charge and the vehicle's required power includes: obtaining a urea pump pressure reference value of the urea pump when the engine is running; obtaining a state of charge threshold for starting the engine, and determining a first adjustment coefficient according to the state of charge and the state of charge threshold; obtaining a vehicle's required power threshold for starting the engine, and determining a second adjustment coefficient according to the vehicle's required power and the vehicle's required power threshold; determining a urea pump pressure requirement value according to the first adjustment coefficient, the second adjustment coefficient and the urea pump pressure reference value.

[0008] Optionally, adjusting the urea pump pressure according to the state of charge and the required power of the whole vehicle also includes: obtaining a current measured value of the urea pump pressure, and calculating a pressure deviation between the current measured value and the required value of the urea pump pressure; when the pressure deviation is greater than or equal to a pressure deviation threshold, adjusting the urea pump pressure based on the required value of the urea pump pressure; when the pressure deviation is less than the pressure deviation threshold, maintaining the current urea pump pressure unchanged.

[0009] Optionally, the first adjustment coefficient is positively correlated with the state of charge; and the second adjustment coefficient is negatively correlated with the required power of the entire vehicle.

[0010] Optionally, the aftertreatment system of the engine includes an SCR system and a particulate trap; determining whether to control the urea pump to release pressure according to the aftertreatment temperature includes: obtaining a first temperature threshold and a second temperature threshold, wherein the first temperature threshold is less than the second temperature threshold, and the second temperature threshold is less than the urea injection temperature of the aftertreatment system; obtaining a pre-SCR temperature upstream of the SCR system; when the pre-SCR temperature is less than or equal to the first temperature threshold, controlling the urea pump to release pressure; when the pre-SCR temperature is greater than or equal to the second temperature threshold, controlling the urea pump not to release pressure.

[0011] Optionally, the urea pump pressure control method of the hybrid vehicle further includes: when the pre-SCR temperature is greater than the first temperature threshold and less than the second temperature threshold, obtaining the pre-DPF temperature upstream of the particulate trap, and controlling the urea pump not to release pressure when the pre-DPF temperature is greater than or equal to a third temperature threshold; wherein the third temperature threshold is greater than the urea injection temperature.

[0012] Optionally, the urea pump pressure control method of the hybrid vehicle further includes: acquiring an actual ammonia storage value in a post-treatment system of the engine; determining a correction coefficient according to the actual ammonia storage value and an ammonia storage set value; and correcting the urea pump pressure according to the correction coefficient.

[0013] Optionally, when the engine is stopped and the urea pump does not release pressure, the method further includes: acquiring a leakage amount of a urea nozzle of the engine, and controlling the urea pump to release pressure when the leakage amount of the urea nozzle is greater than a leakage amount threshold.

[0014] According to another aspect of the present invention, a urea pump pressure control device for a hybrid vehicle is provided, the hybrid vehicle comprising an engine and a power battery, the device comprising: a first acquisition module, for acquiring a post-processing temperature of the engine after the engine is stopped; a pressure relief evaluation module, for determining whether to control the urea pump to relieve pressure according to the post-processing temperature; a second acquisition module, for acquiring a state of charge of the power battery and a whole vehicle required power of the hybrid vehicle when the urea pump does not relieve pressure; a control module, for adjusting the urea pump pressure according to the state of charge and the whole vehicle required power; wherein the urea pump pressure is lower than the injection pressure of the urea pump when the engine is running.

[0015] According to another aspect of the present invention, an electronic device is provided, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the above-mentioned urea pump pressure control method for a hybrid vehicle.

[0016] The technical solution of the embodiment of the present invention is to obtain the post-treatment temperature of the engine after the engine is shut down; determine whether to control the urea pump pressure relief according to the post-treatment temperature; obtain the state of charge of the power battery and the required power of the hybrid vehicle when the urea pump does not relieve pressure; adjust the urea pump pressure according to the state of charge and the required power of the vehicle, so that the urea pump pressure is lower than the injection pressure of the urea pump when the engine is running. By controlling the urea pump pressure to maintain a certain level during the engine shutdown process, the leakage of the urea nozzle is reduced, and urea crystallization in the mixer is avoided; at the same time, the urea injection system can reach the injection pressure as soon as possible after the engine is started, avoiding excessive exhaust emissions, solving the existing problem of long pressure buildup time after urea spray pressure relief under frequent engine start-stop conditions, and the inability to inject urea during the pressure buildup period, resulting in excessive nitrogen oxide emissions, and improving the exhaust emission treatment effect of the hybrid system.

[0017] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A flow chart of a urea pump pressure control method for a hybrid vehicle provided by an embodiment of the present invention;

[0020] Figure 2 A flow chart of a urea pump pressure control method based on the state of charge and the required power of the whole vehicle provided in an embodiment of the present invention;

[0021] Figure 3 A flow chart of another urea pump pressure control method based on the state of charge and the required power of the whole vehicle provided in an embodiment of the present invention;

[0022] Figure 4 A flow chart of a urea pump pressure relief control method provided by an embodiment of the present invention;

[0023] Figure 5 A flow chart of another urea pump pressure relief control method provided by an embodiment of the present invention;

[0024] Figure 6 A flow chart of another urea pump pressure control method for a hybrid vehicle provided by an embodiment of the present invention;

[0025] Figure 7 A flow chart of another urea pump pressure control method for a hybrid vehicle provided by an embodiment of the present invention;

[0026] Figure 8 A schematic structural diagram of a urea pump pressure control device for a hybrid vehicle provided by an embodiment of the present invention;

[0027] Fig. 9 It is a structural schematic diagram of an electronic device for implementing the urea pump pressure control method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] Figure 1 A flow chart of a urea pump pressure control method for a hybrid vehicle provided in an embodiment of the present invention. This embodiment can be applicable to the start-stop condition of a hybrid system diesel engine. The method can be executed by a urea pump pressure control device. The urea pump pressure control device can be implemented in the form of hardware and / or software. The urea pump pressure control device can be configured in an engine controller or an independent electronic device.

[0031] In the present application, a hybrid vehicle includes an engine and a power battery, and the post-treatment system of the engine includes a urea injection system, an SCR system (Selective Catalytic Reduction) and a particulate filter. Among them, the urea injection system includes a urea pump, a urea tank, a urea nozzle and a connecting pipeline. After the engine is running, when the post-treatment temperature is greater than a certain value, the urea pump will draw from the urea tank and maintain the injection pressure (for example, 9 bar), and transport it to the urea nozzle through a pipeline. The urea nozzle performs injection according to the post-treatment temperature and the injection conditions of the nitrogen oxide original lamp. The SCR system is part of the diesel engine post-treatment, including a mixer and a carrier catalyst. Urea is injected in the mixer and mixed with the exhaust gas. Urea is hydrolyzed to generate ammonia to react with nitrogen oxides in the diesel engine exhaust to reduce nitrogen oxide emissions. A particulate filter (DPF) is a device installed in the automobile emission system for capturing and treating particulate emissions in the exhaust gas generated by the engine.

[0032] See also Figure 1 As shown, the urea pump pressure control method of the hybrid vehicle of the present application includes:

[0033] S1: After the engine is stopped, the aftertreatment temperature of the engine is obtained.

[0034] The post-treatment temperature can be understood as the temperature of the equipment or pipeline in the diesel engine post-treatment system that has a greater impact on the leakage of the urea nozzle. The post-treatment temperature includes but is not limited to at least one of the following: the temperature upstream of the SCR system, downstream of the SCR system and in the SCR mixer, and the temperature upstream of the DPF, downstream of the DPF and in the DPF carrier.

[0035] In this embodiment, the post-treatment temperature can be acquired based on the temperature detection elements arranged around the SCR system and the DPF. Specifically, whether the engine is shut down can be identified by the engine shutdown requirement and the shutdown detection flag. After the engine shutdown is identified, the corresponding post-treatment temperature can be obtained by reading the temperature sensor arranged on the post-treatment system.

[0036] S2: Determine whether to control the urea pump pressure relief according to the post-treatment temperature.

[0037] The urea pump pressure relief can be understood as the process of releasing the urea pump pressure to 0; the urea pump non-pressure relief can be understood as controlling the urea pump pressure to be greater than 0, that is, controlling the urea pump to maintain a specific pressure.

[0038] In this embodiment, the post-treatment temperature may be compared with the temperature satisfying the urea injection condition (i.e., the urea injection temperature), and whether to control the urea pump to release pressure may be determined according to the deviation between the post-treatment temperature and the temperature satisfying the urea injection condition. Specifically, the urea pump may be controlled to release pressure when the post-treatment temperature is relatively low (e.g., lower than the urea injection temperature, and the temperature difference with the urea injection temperature exceeds 10°C), and the urea pump may be controlled not to release pressure when the post-treatment temperature is relatively high (e.g., lower than the urea injection temperature, and the temperature difference with the urea injection temperature is less than 10°C).

[0039] S3: When the urea pump is not releasing pressure, the state of charge of the power battery and the required power of the hybrid vehicle are obtained.

[0040] Among them, the state of charge can be understood as a parameter that characterizes the remaining power of the power battery, which is recorded as SOC. SOC is any value greater than or equal to 0% and less than or equal to 100%. The SOC when the power battery is fully charged is 100%, and the SOC when the power battery is completely exhausted is 0%. In this embodiment, the state of charge of the power battery can be obtained in real time through the vehicle communication network.

[0041] The vehicle power requirement can be understood as the total power required by the power system during the driving or operation of the hybrid vehicle. In this embodiment, the vehicle power requirement provided by the vehicle controller can be obtained in real time through the vehicle communication network, or the vehicle power requirement can be calculated by the throttle opening.

[0042] S4: Adjust the urea pump pressure according to the state of charge and the power required by the vehicle.

[0043] The urea pump pressure is lower than the injection pressure of the urea pump when the engine is running.

[0044] In this embodiment, the state of charge and the required power of the vehicle can reflect the demand for starting the vehicle engine. The higher the demand for starting the vehicle engine, the higher the urea pump pressure; the lower the demand for starting the vehicle engine, the lower the urea pump pressure.

[0045] Specifically, after the engine is shut down, the urea pump does not release pressure when the after-treatment temperature is high to ensure that urea can be injected normally after the engine is started. At the same time, the urea pump pressure is controlled according to the charge state and the power demand of the whole vehicle. When the charge state of the power battery decreases or the power demand of the whole vehicle increases, the demand for starting the engine of the vehicle increases, and it is necessary to maintain a higher urea pump pressure while making the urea pump pressure lower than the urea pump injection pressure.

[0046] Therefore, the technical solution of the present application can reduce the leakage of the urea nozzle and avoid urea crystallization in the mixer by controlling the urea pump pressure to maintain a certain level during the engine shutdown process. At the same time, the urea injection system can reach the injection pressure as soon as possible after the engine is started to avoid excessive exhaust emissions. This solves the existing problem that under the condition of frequent engine start-stop, the pressure building time after urea injection is long and urea cannot be injected during the pressure building period, resulting in excessive nitrogen oxide emissions. This improves the exhaust emission treatment effect of the hybrid system.

[0047] Figure 2 This is a flow chart of a urea pump pressure control method based on the state of charge and the vehicle power requirement provided by an embodiment of the present invention. Figure 2 As shown, in the above step S4, the urea pump pressure is adjusted according to the state of charge and the required power of the vehicle, including the following steps:

[0048] S401: Acquire a urea pump pressure reference value when the engine is running.

[0049] The urea pump pressure reference value can be understood as the initial setting value of the urea pump injection pressure when the engine is running. In this embodiment, the urea pump pressure reference value is a calibrated value or a preset value, and its specific value is not limited. For example, the urea pump pressure reference value can be set to 9 bar.

[0050] S402: Obtaining a state of charge threshold for starting the engine, and determining a first adjustment coefficient according to the state of charge and the state of charge threshold.

[0051] The state of charge threshold may be the minimum remaining power of the power battery that requires the engine to be started when the vehicle is unloaded. For example, the state of charge threshold may be set to 20%.

[0052] In this embodiment, the first adjustment coefficient may be calculated based on a deviation between the state of charge and the state of charge threshold.

[0053] For example, if the state of charge of the power battery is defined as S, the state of charge threshold is S min , then the first adjustment coefficient can be expressed as .

[0054] S403: Obtaining a vehicle power requirement threshold for starting the engine, and determining a second adjustment coefficient according to the vehicle power requirement and the vehicle power requirement threshold.

[0055] The vehicle power threshold may be the maximum vehicle power required to start the engine when the power battery is fully charged (ie, SOC is 100%). For example, the vehicle power threshold may be set to 180 kW.

[0056] In this embodiment, the second adjustment coefficient can be calculated based on the deviation between the vehicle required power and the vehicle required power threshold.

[0057] For example, if the vehicle power requirement is defined as P, the state of charge threshold is P max , then the second adjustment coefficient can be expressed as .

[0058] S404: Determine a urea pump pressure requirement value according to the first adjustment coefficient, the second adjustment coefficient, and a urea pump pressure reference value.

[0059] In this embodiment, the urea pump pressure adjustment value can be calculated according to the product or weighted product of the first adjustment coefficient, the second adjustment coefficient and the urea pump pressure reference value, and the final urea pump pressure demand value is calculated by subtracting the urea pump pressure adjustment value from the urea pump pressure reference value.

[0060] Optionally, the first adjustment coefficient is positively correlated with the state of charge; and the second adjustment coefficient is negatively correlated with the required power of the entire vehicle.

[0061] Specifically, when maintaining the urea pump pressure, the pressure is adjusted based on the state of charge and the required power of the vehicle. When the state of charge is low, the torque of the power motor is limited, and the probability of the engine starting is high. Therefore, the first adjustment coefficient is set to be positively correlated with the state of charge, so that when the state of charge is low, the adjustment value is reduced, and the urea pump is maintained at a higher pressure to ensure that urea can be injected as soon as possible after the engine is started. When the vehicle requires a high power, the vehicle will require the engine to start at any time. Therefore, the second adjustment coefficient is set to be negatively correlated with the vehicle's required power, so that when the vehicle requires a high power, the adjustment value is reduced, and the urea pump is maintained at a higher pressure to ensure that urea can be injected as soon as possible after the engine is started.

[0062] For example, the urea pump pressure requirement value can be calculated using the following formula 1:

[0063] (Formula 1)

[0064] in, Indicates the pressure requirement value of the urea pump; Indicates the urea pump pressure reference value when the engine is running.

[0065] Therefore, the technical solution of the present application adaptively adjusts the urea pump pressure by obtaining the state of charge of the power battery and the required power of the whole vehicle. The adjustment strategy of the urea pump pressure satisfies: as the state of charge increases, the required pressure of the urea pump decreases; as the required power of the whole vehicle decreases, the required pressure of the urea pump decreases, which can improve the control effect of the urea pump under different working conditions and reduce the leakage of the urea nozzle.

[0066] Figure 3This is a flow chart of another urea pump pressure control method based on the state of charge and the vehicle power requirement provided by an embodiment of the present invention. Figure 3 As shown, in the above step S4, the urea pump pressure is adjusted according to the state of charge and the required power of the vehicle, including:

[0067] S401: Acquire a urea pump pressure reference value when the urea pump is in the engine running state.

[0068] S402: Obtaining a state of charge threshold for starting the engine, and determining a first adjustment coefficient according to the state of charge and the state of charge threshold.

[0069] S403: Obtaining a vehicle power requirement threshold for starting the engine, and determining a second adjustment coefficient according to the vehicle power requirement and the vehicle power requirement threshold.

[0070] S404: Determine a urea pump pressure requirement value according to the first adjustment coefficient, the second adjustment coefficient, and a urea pump pressure reference value.

[0071] S405: Obtaining a current measured value of the urea pump pressure, and calculating a pressure deviation between the current measured value and a required value of the urea pump pressure.

[0072] S406: Determine whether the pressure deviation is greater than or equal to a pressure deviation threshold.

[0073] The pressure deviation threshold may be adaptively adjusted based on the pressure value required for the urea pump to maintain normal operation when the engine is stopped. For example, the pressure deviation threshold may be set to 1 bar.

[0074] If the pressure deviation is greater than or equal to the pressure deviation threshold, step S407 is executed; if the pressure deviation is less than the pressure deviation threshold, step S408 is executed.

[0075] S407: Adjusting the urea pump pressure based on the urea pump pressure demand value.

[0076] S408: Maintain the current urea pump pressure unchanged.

[0077] Specifically, when the pressure deviation between the current measured value of the urea pump pressure and the required value of the urea pump pressure is greater than or equal to the pressure deviation threshold, the urea pump pressure adjustment strategy is executed, and the urea pump pressure is adaptively adjusted according to the calculated urea pump pressure requirement value; when the pressure deviation between the current measured value of the urea pump pressure and the required value of the urea pump pressure is less than the pressure deviation threshold, the urea pump pressure adjustment strategy is not executed, and the current urea pump pressure is maintained unchanged. By monitoring the pressure deviation and adjusting the urea pump pressure, frequent changes in the urea pump pressure can be avoided, thereby improving system stability.

[0078] Figure 4This is a flow chart of a urea pump pressure relief control method provided by an embodiment of the present invention. Figure 4 As shown, in the above step S2, determining whether to control the urea pump pressure relief according to the post-processing temperature includes:

[0079] S201: Acquire a first temperature threshold and a second temperature threshold.

[0080] The first temperature threshold is less than the second temperature threshold, and the second temperature threshold is less than the urea injection temperature of the post-treatment system. For example, taking the urea injection temperature as 180°C as an example, the first temperature threshold can be set to 170°C and the second temperature threshold can be set to 175°C.

[0081] S202: Obtain the pre-SCR temperature upstream of the SCR.

[0082] S203: Determine whether the pre-SCR temperature is less than or equal to a first temperature threshold.

[0083] If the pre-SCR temperature is less than or equal to the first temperature threshold, step S204 is executed; if the pre-SCR temperature is greater than the first temperature threshold, step S205 is executed.

[0084] S204: Control the urea pump to release pressure.

[0085] S205: Determine whether the pre-SCR temperature is greater than or equal to a second temperature threshold.

[0086] If the pre-SCR temperature is greater than or equal to the second temperature threshold, step S206 is executed; if the pre-SCR temperature is less than the second temperature threshold, the process returns to step S202 and continues to execute.

[0087] S206: Control the urea pump to prevent pressure relief.

[0088] Specifically, after the engine is shut down, the temperature value measured by the temperature sensor arranged upstream of the SCR system is first collected and recorded as the pre-SCR temperature. If the pre-SCR temperature is less than or equal to the first temperature threshold t1 (lower than the urea injection temperature, for example, 170°C), the urea pump is controlled to release pressure to reduce the urea pump pressure to 0; if the pre-SCR temperature is greater than or equal to the second temperature threshold t2 (higher than t1 and lower than the urea injection temperature, for example, 175°C), the urea pump is controlled not to release pressure and maintain a certain pressure.

[0089] Figure 5 This is a flow chart of another urea pump pressure relief control method provided by an embodiment of the present invention. Figure 5 As shown, in the above step S2, determining whether to control the urea pump pressure relief according to the post-processing temperature includes:

[0090] S201: Acquire a first temperature threshold and a second temperature threshold.

[0091] S202: Obtain the pre-SCR temperature upstream of the SCR.

[0092] S203: Determine whether the pre-SCR temperature is less than or equal to a first temperature threshold.

[0093] If the pre-SCR temperature is less than or equal to the first temperature threshold, step S204 is executed; if the pre-SCR temperature is greater than the first temperature threshold, step S205 is executed.

[0094] S204: Control the urea pump to release pressure.

[0095] S205: Determine whether the pre-SCR temperature is greater than or equal to a second temperature threshold.

[0096] If the pre-SCR temperature is greater than or equal to the second temperature threshold, step S206 is executed; if the pre-SCR temperature is greater than the first temperature threshold and less than the second temperature threshold, the process returns to step S207.

[0097] S206: Control the urea pump to prevent pressure relief.

[0098] S207: Obtaining a pre-DPF temperature upstream of the particulate trap, and controlling the urea pump not to release pressure when the pre-DPF temperature is greater than or equal to a third temperature threshold.

[0099] The third temperature threshold is greater than the urea injection temperature.

[0100] Specifically, after the engine is shut down, if the temperature before the SCR is higher than the first temperature threshold t1 and lower than the second temperature threshold t2, the temperature before the DPF upstream of the particulate trap is further collected. When the temperature before the DPF is lower than the third temperature threshold t3 (higher than the urea injection temperature, such as 190°C), it indicates that the SCR temperature will not rise immediately after the engine is restarted. At this time, the urea pump is controlled to release pressure; when the temperature before the DPF is greater than or equal to the third temperature threshold t3, the urea pump is controlled not to release pressure. By monitoring the SCR temperature and the DPF temperature to control the urea pump pressure relief, the urea pump can be quickly built up under different working conditions to avoid the failure to inject urea during the re-pressure build-up after the pressure relief, resulting in excessive nitrogen oxide emissions.

[0101] Figure 6 A flowchart of another urea pump pressure control method for a hybrid vehicle provided by an embodiment of the present invention is shown in FIG. Figure 6 As shown, the urea pump pressure control method of the hybrid vehicle of the present application includes the following steps:

[0102] S601: After the engine is stopped, obtain the aftertreatment temperature of the engine.

[0103] S602: Determine whether to control the urea pump pressure relief according to the post-processing temperature.

[0104] S603: When the urea pump is not releasing pressure, the state of charge of the power battery and the required power of the hybrid vehicle are obtained.

[0105] S604: Regulate the urea pump pressure according to the state of charge and the power required by the vehicle.

[0106] S605: Obtaining the actual measured value of ammonia storage in the after-treatment system of the engine.

[0107] Among them, ammonia storage can be understood as the ammonia after urea hydrolysis reacts with nitrogen oxides, and the remaining ammonia will be stored in the SCR carrier. When urea injection is insufficient, the ammonia stored in the SCR carrier will be released to react with nitrogen oxides. Ammonia storage changes dynamically, and the diesel engine controller will control the reduction or increase of urea injection based on the state of ammonia storage.

[0108] S606: Determine a correction coefficient according to the actual ammonia storage value and the ammonia storage set value.

[0109] The ammonia storage setting value may be understood as a calibrated value of the ammonia storage amount in the SCR carrier when the engine is running.

[0110] In this embodiment, the correction coefficient can be determined by looking up a table based on the relative relationship between the actual ammonia storage value and the ammonia storage set value.

[0111] S607: Correct the urea pump pressure according to the correction coefficient.

[0112] Specifically, if the measured ammonia storage value is defined as N a , ammonia storage set value N d , then the ratio of the measured ammonia storage value to the set ammonia storage value can be expressed as k (k = N a / N d ), a preset MAP is established based on the corresponding relationship between the ratio k and the correction coefficient of ammonia storage, and the preset MAP is queried based on the ratio k to obtain the correction coefficient. If the correction coefficient is defined as a, the urea pump pressure demand value calculated based on the state of charge and the vehicle required power is , then the corrected urea pump pressure can be expressed as , where the corrected urea pump pressure is Satisfies: greater than 0, and less than or equal to the urea pump pressure reference value when the engine is running Therefore, by detecting the ammonia storage state in the post-treatment system, the urea pump pressure is corrected. When the ammonia storage is high, the urea pump pressure is further reduced to reduce the risk of urea nozzle leakage.

[0113] Figure 7A flowchart of another urea pump pressure control method for a hybrid vehicle provided in an embodiment of the present invention is shown in FIG. Figure 7 As shown, the urea pump pressure control method of the hybrid vehicle of the present application includes the following steps:

[0114] S701: After the engine is stopped, obtain the aftertreatment temperature of the engine.

[0115] S702: Determine whether to control the urea pump pressure relief according to the post-processing temperature.

[0116] S703: When the urea pump is not releasing pressure, the state of charge of the power battery and the required power of the hybrid vehicle are obtained.

[0117] S704: Regulate the urea pump pressure according to the state of charge and the power required by the vehicle.

[0118] S705: Obtain the leakage amount of the urea nozzle of the engine, and control the urea pump to release pressure when the leakage amount of the urea nozzle is greater than a leakage amount threshold.

[0119] The leakage threshold is the maximum leakage that meets the urea nozzle leakage requirement.

[0120] Specifically, when the engine is stopped and the urea pump does not release pressure, the urea nozzle leakage is monitored in real time, and the urea pump is controlled to release pressure when the urea nozzle leakage is greater than the leakage threshold, thereby avoiding an increase in urea leakage caused by the urea pump not releasing pressure and improving system reliability.

[0121] Based on the same inventive concept as the above embodiments, an embodiment of the present invention further provides a urea pump pressure control device for a hybrid vehicle. The urea pump pressure control device for a hybrid vehicle can execute the urea pump pressure control method for a hybrid vehicle provided by any embodiment of the present invention, and has functional modules and beneficial effects corresponding to the execution method.

[0122] Figure 8 The present invention provides a schematic diagram of the structure of a urea pump pressure control device for a hybrid vehicle. Figure 8 As shown, the urea pump pressure control device of the hybrid vehicle includes: a first acquisition module 101 , a pressure relief evaluation module 102 , a second acquisition module 103 and a control module 104 .

[0123] Among them, the first acquisition module 101 is used to obtain the post-processing temperature of the engine after the engine is stopped; the pressure relief evaluation module 102 is used to determine whether to control the urea pump to release pressure according to the post-processing temperature; the second acquisition module 103 is used to obtain the charge state of the power battery and the vehicle power demand of the hybrid vehicle when the urea pump does not release pressure; the control module 104 is used to adjust the urea pump pressure according to the charge state and the vehicle power demand; wherein the urea pump pressure is lower than the injection pressure of the urea pump when the engine is running.

[0124] Optionally, the control module 104 is configured to: obtain a urea pump pressure reference value when the urea pump is in the engine running state; obtain a state of charge threshold value for starting the engine, and determine a first adjustment coefficient based on the state of charge and the state of charge threshold value; obtain a vehicle power requirement threshold for starting the engine, and determine a second adjustment coefficient based on the vehicle power requirement and the vehicle power requirement threshold value; determine a urea pump pressure requirement value based on the first adjustment coefficient, the second adjustment coefficient and the urea pump pressure reference value.

[0125] Optionally, the control module 104 is further configured to: obtain a current measured value of the urea pump pressure, and calculate a pressure deviation between the current measured value and a urea pump pressure demand value; when the pressure deviation is greater than or equal to a pressure deviation threshold, adjust the urea pump pressure based on the urea pump pressure demand value; when the pressure deviation is less than the pressure deviation threshold, maintain the current urea pump pressure unchanged.

[0126] Optionally, the first adjustment coefficient is positively correlated with the state of charge; and the second adjustment coefficient is negatively correlated with the required power of the entire vehicle.

[0127] Optionally, the post-treatment system of the engine includes an SCR system and a particle trap. The pressure relief assessment module 102 of the present application is configured to: obtain a first temperature threshold and a second temperature threshold, wherein the first temperature threshold is less than the second temperature threshold, and the second temperature threshold is less than the urea injection temperature of the post-treatment system; obtain the pre-SCR temperature upstream of the SCR system; when the pre-SCR temperature is less than or equal to the first temperature threshold, control the urea pump to release pressure; when the pre-SCR temperature is greater than or equal to the second temperature threshold, control the urea pump not to release pressure.

[0128] Optionally, the pressure relief assessment module 102 of the present application is also configured to: obtain the pre-DPF temperature upstream of the particulate trap when the pre-SCR temperature is greater than the first temperature threshold and less than the second temperature threshold, and control the urea pump not to relieve pressure when the pre-DPF temperature is greater than or equal to a third temperature threshold; wherein the third temperature threshold is greater than the urea injection temperature.

[0129] Optionally, the urea pump pressure control device of the hybrid vehicle of the present application is further configured to: obtain an actual ammonia storage value in the aftertreatment system of the engine; determine a correction coefficient based on the actual ammonia storage value and an ammonia storage set value; and correct the urea pump pressure based on the correction coefficient.

[0130] Optionally, the urea pump pressure control device of the hybrid vehicle of the present application is further configured to: when the engine is stopped and the urea pump is not releasing pressure, obtain the urea nozzle leakage of the engine, and control the urea pump to release pressure when the urea nozzle leakage is greater than a leakage threshold.

[0131] Based on the above-mentioned inventive concept, an embodiment of the present invention provides an electronic device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the above-mentioned urea pump pressure control method for the hybrid vehicle.

[0132] Fig. 9 A schematic diagram of the structure of an electronic device 10 that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0133] like Fig. 9 As shown, the electronic device 10 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. The input / output (I / O) interface 15 is also connected to the bus 14.

[0134] A number of components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0135] The processor 11 may be a variety of general and / or dedicated processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as the above-mentioned urea pump pressure control method for a hybrid vehicle.

[0136] In some embodiments, the urea pump pressure control method for the hybrid vehicle described above may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the urea pump pressure control method for the hybrid vehicle described above may be executed. Alternatively, in other embodiments, the processor 11 may be configured to execute the urea pump pressure control method for the hybrid vehicle described above in any other appropriate manner (e.g., by means of firmware).

[0137] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0138] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0139] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, device, or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0140] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0141] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0142] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0143] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0144] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling urea pump pressure of a hybrid vehicle, wherein the hybrid vehicle comprises an engine and a power battery, characterized in that: The method comprises: After the engine is stopped, obtaining a post-processing temperature of the engine; determining whether to control the urea pump to release pressure according to the post-processing temperature; When the urea pump is not releasing pressure, obtaining the state of charge of the power battery and the whole vehicle required power of the hybrid vehicle; adjusting the urea pump pressure according to the state of charge and the required power of the whole vehicle; The urea pump pressure is lower than the injection pressure of the urea pump when the engine is running.

2. The urea pump pressure control method for a hybrid vehicle according to claim 1, characterized in that: The adjusting the urea pump pressure according to the state of charge and the required power of the whole vehicle includes: Acquiring a urea pump pressure reference value of the urea pump when the engine is running; Acquiring a state of charge threshold value for starting the engine, and determining a first adjustment coefficient according to the state of charge and the state of charge threshold value; Obtaining a vehicle power requirement threshold for starting the engine, and determining a second adjustment coefficient according to the vehicle power requirement and the vehicle power requirement threshold; A urea pump pressure requirement value is determined according to the first adjustment coefficient, the second adjustment coefficient, and the urea pump pressure reference value.

3. The urea pump pressure control method for a hybrid vehicle according to claim 2, characterized in that: The step of adjusting the urea pump pressure according to the state of charge and the required power of the vehicle further includes: Acquiring a current measured value of the urea pump pressure, and calculating a pressure deviation between the current measured value and a required value of the urea pump pressure; When the pressure deviation is greater than or equal to a pressure deviation threshold, adjusting the urea pump pressure based on the urea pump pressure demand value; When the pressure deviation is less than the pressure deviation threshold, the current urea pump pressure is maintained unchanged.

4. The urea pump pressure control method for a hybrid vehicle according to claim 2, characterized in that: The first adjustment coefficient is positively correlated with the state of charge; The second adjustment coefficient is negatively correlated with the required power of the entire vehicle.

5. The urea pump pressure control method for a hybrid vehicle according to claim 1, characterized in that: The after-treatment system of the engine includes an SCR system and a particle trap; The determining whether to control the urea pump pressure relief according to the post-processing temperature includes: Acquire a first temperature threshold and a second temperature threshold, wherein the first temperature threshold is less than the second temperature threshold, and the second temperature threshold is less than a urea injection temperature of the post-treatment system; Obtaining a pre-SCR temperature upstream of the SCR system; When the pre-SCR temperature is less than or equal to the first temperature threshold, controlling the urea pump to release pressure; When the pre-SCR temperature is greater than or equal to the second temperature threshold, the urea pump is controlled not to release pressure.

6. The urea pump pressure control method for a hybrid vehicle according to claim 5, characterized in that: Also includes: When the pre-SCR temperature is greater than the first temperature threshold and less than the second temperature threshold, acquiring a pre-DPF temperature upstream of the particulate trap, and controlling the urea pump not to release pressure when the pre-DPF temperature is greater than or equal to a third temperature threshold; The third temperature threshold is greater than the urea injection temperature.

7. The urea pump pressure control method for a hybrid vehicle according to any one of claims 1 to 6, characterized in that: Also includes: Obtaining a measured value of ammonia storage in a post-treatment system of the engine; Determining a correction coefficient according to the ammonia storage measured value and the ammonia storage set value; The urea pump pressure is corrected according to the correction coefficient.

8. The urea pump pressure control method for a hybrid vehicle according to any one of claims 1 to 6, characterized in that: When the engine is stopped and the urea pump does not release pressure, the method further includes: The leakage amount of the urea nozzle of the engine is obtained, and the urea pump is controlled to release pressure when the leakage amount of the urea nozzle is greater than a leakage amount threshold.

9. A urea pump pressure control device for a hybrid vehicle, the hybrid vehicle comprising an engine and a power battery, characterized in that: The device comprises: A first acquisition module, configured to acquire a post-processing temperature of the engine after the engine is stopped; a pressure relief evaluation module, used for determining whether to control the pressure relief of the urea pump according to the post-processing temperature; a second acquisition module, configured to acquire the state of charge of the power battery and the vehicle required power of the hybrid vehicle when the urea pump is not releasing pressure; A control module, used for adjusting the urea pump pressure according to the state of charge and the required power of the whole vehicle; The urea pump pressure is lower than the injection pressure of the urea pump when the engine is running.

10. An electronic device, characterized in that: The electronic device comprises: at least one processor; and, a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the urea pump pressure control method for a hybrid vehicle according to any one of claims 1 to 8.

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