Urea Pump Pressure Control Method, Control Device and Electronic Equipment for Hybrid Vehicle

Abstract

The present invention discloses a urea pump pressure control method, a control device and an electronic device for a hybrid vehicle. The method includes: after the engine stops, obtaining the post-treatment temperature of the engine; determining whether to control the urea pump to relieve pressure according to the post-treatment temperature; when the urea pump does not relieve pressure, obtaining the state of charge of the power battery and the vehicle's overall demand power of the hybrid vehicle; adjusting the urea pump pressure according to the state of charge and the vehicle's overall demand power, so that the urea pump pressure is lower than the injection pressure of the urea pump in the engine running state. By controlling a certain urea pump pressure during the engine shutdown process, the present invention reduces the leakage amount of the urea nozzle, avoids urea crystallization in the mixer; at the same time, the urea injection system can reach the injection pressure as soon as possible after the engine starts, avoiding excessive exhaust emissions.

Description

Technical Field

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

[0002] A diesel hybrid system is a power system that combines a diesel engine and an electric motor. During the operation of the whole vehicle, the vehicle controller (Hybrid Control Unit, abbreviated as HCU) controls the shutdown and startup of the diesel engine according to the vehicle state. For example, in the working condition where the power battery has a high power level and the vehicle demand power is low, the vehicle power demand is small, and the diesel engine is controlled to shut down.

[0003] A diesel engine is usually equipped with a urea injection system for injecting 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 pipelines. After the engine runs and the post-treatment temperature is greater than a certain value, the urea pump sucks from the urea tank and maintains a certain pressure (for example, 9 bar), and transports it to the urea nozzle through the pipeline. The urea nozzle performs injection according to the post-treatment temperature and the nitrogen oxide original emission lamp injection conditions. Since the urea nozzle is installed before the Selective Catalytic Reduction (SCR) system, there will be some leakage when the urea is not injected.

[0004] In a diesel hybrid vehicle, the engine has many start-stop working conditions. After the engine shuts down, the urea pump relieves pressure; when the engine starts again, the urea pump needs to successfully establish a new pressure according to the temperature conditions. However, since it usually takes 20 to 30 seconds for the urea pump to establish pressure, the urea injection system cannot inject urea during this time, which easily leads to the problem of excessive nitrogen oxide emissions and affects 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 problem that in the existing frequent start-stop working conditions of the engine, the urea pump takes a long time to build pressure after relieving pressure, and urea cannot be injected during the pressure building period, resulting in excessive nitrogen oxide emissions. By controlling the urea pump not to relieve pressure and simultaneously reducing the urea pump pressure after the engine shuts down, the pressure building time of the urea pump is shortened and the urea leakage amount is reduced.

[0006] According to an aspect of the present invention, there is provided a method for controlling the pressure of a urea pump in a hybrid vehicle, the hybrid vehicle including an engine and a power battery, the method including: after the engine stops, obtaining the post-treatment temperature of the engine; determining whether to control the urea pump to relieve pressure according to the post-treatment temperature; when the urea pump does not relieve pressure, obtaining the state of charge of the power battery and the vehicle-wide demand power of the hybrid vehicle; adjusting the urea pump pressure according to the state of charge and the vehicle-wide demand power; wherein, the urea pump pressure is lower than the injection pressure of the urea pump in the engine operating state.

[0007] Optionally, the adjusting the urea pump pressure according to the state of charge and the vehicle-wide demand power includes: obtaining a reference value of the urea pump pressure in the engine operating state; 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-wide demand power threshold for starting the engine, and determining a second adjustment coefficient according to the vehicle-wide demand power and the vehicle-wide demand power threshold; determining a urea pump pressure demand value according to the first adjustment coefficient, the second adjustment coefficient and the reference value of the urea pump pressure.

[0008] Optionally, the adjusting the urea pump pressure according to the state of charge and the vehicle-wide demand power further includes: obtaining a current measured value of the urea pump pressure, and calculating a pressure deviation between the current measured value and the urea pump pressure demand value; 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, maintaining the current urea pump pressure unchanged.

[0009] Optionally, the first adjustment coefficient is positively correlated with the state of charge; the second adjustment coefficient is negatively correlated with the vehicle-wide demand power.

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

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

[0012] Optionally, the urea pump pressure control method for the hybrid vehicle further includes: obtaining the measured value of ammonia storage in the aftertreatment system of the engine; determining a correction coefficient according to the measured value of ammonia storage and the set value of ammonia storage; and correcting the urea pump pressure according to the correction coefficient.

[0013] Optionally, when the engine is shut down and the urea pump does not relieve pressure, the method further includes: obtaining the leakage amount of the urea nozzle of the engine, and controlling the urea pump to relieve pressure when the leakage amount of the urea nozzle is greater than the leakage amount threshold.

[0014] According to another aspect of the present invention, there is provided a urea pump pressure control device for a hybrid vehicle, the hybrid vehicle including an engine and a power battery, the device including: a first acquisition module, configured to acquire the aftertreatment temperature of the engine after the engine is shut down; a pressure relief evaluation module, configured to determine whether to control the urea pump to relieve pressure according to the aftertreatment temperature; a second acquisition module, configured to acquire the state of charge of the power battery and the vehicle-wide demand power of the hybrid vehicle when the urea pump does not relieve pressure; a control module, configured to adjust the urea pump pressure according to the state of charge and the vehicle-wide demand power; wherein, the urea pump pressure is lower than the injection pressure of the urea pump in the engine operating state.

[0015] According to another aspect of the present invention, there is provided an electronic device, the electronic device including: 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.

[0016] In the technical solution of the embodiment of the present invention, after the engine stops, the post-treatment temperature of the engine is obtained; it is determined whether to control the urea pump to relieve pressure according to the post-treatment temperature; when the urea pump does not relieve pressure, the state of charge of the power battery and the vehicle demand power of the hybrid vehicle are obtained; the urea pump pressure is adjusted according to the state of charge and the vehicle demand power, so that the urea pump pressure is lower than the injection pressure of the urea pump during the engine operation state. By controlling a certain urea pump pressure during the engine shutdown process, the leakage amount of the urea nozzle is reduced, and the crystallization of urea 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 starts, avoiding excessive exhaust emissions, solving the problem that in the existing frequent start-stop working conditions of the engine, the pressure building time is long after the urea injection pressure is relieved, and urea cannot be injected during the pressure building 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 content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used 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 drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings without creative efforts based on these drawings.

[0019] Figure 1 It is a flowchart of a method for controlling the urea pump pressure of a hybrid vehicle provided by an embodiment of the present invention;

[0020] Figure 2 It is a flowchart of a method for controlling the urea pump pressure based on the state of charge and vehicle demand power provided by an embodiment of the present invention;

[0021] Figure 3 It is a flowchart of another method for controlling the urea pump pressure based on the state of charge and vehicle demand power provided by an embodiment of the present invention;

[0022] Figure 4 It is a flowchart of a method for controlling the urea pump to relieve pressure provided by an embodiment of the present invention;

[0023] Figure 5 It is a flowchart of another method for controlling the urea pump to relieve pressure provided by an embodiment of the present invention;

[0024] Figure 6 It is a flowchart of another method for controlling the urea pump pressure of a hybrid vehicle provided by an embodiment of the present invention;

[0025] Figure 7 It is a flowchart of another urea pump pressure control method provided by an embodiment of the present invention;

[0026] Figure 8 It is a schematic structural diagram of a urea pump pressure control device provided by an embodiment of the present invention;

[0027] Figure 9 It is a schematic structural diagram of an electronic device for implementing the urea pump pressure control method of an embodiment of the present invention. Detailed implementation manners

[0028] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope 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 do not necessarily need to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order different from those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

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

[0031] In this application, a hybrid vehicle includes an engine and a power battery. The aftertreatment system of the engine includes a urea injection system, an SCR system (Selective Catalytic Reduction), and a particulate trap. Among them, the urea injection system includes a urea pump, a urea tank, a urea nozzle, and connecting pipelines. After the engine runs and the aftertreatment temperature is greater than a certain value, the urea pump sucks from the urea tank and maintains the injection pressure (for example, 9 bar), and transports it to the urea nozzle through the pipeline. The urea nozzle performs injection according to the aftertreatment temperature and the injection conditions of the nitrogen oxide raw emission lamp. The SCR system is a part of the diesel engine aftertreatment, including a mixer and a carrier catalyst. Urea is injected into the mixer and mixed with the exhaust gas, and ammonia is generated through urea hydrolysis to react with the nitrogen oxides in the diesel engine exhaust gas to reduce the nitrogen oxide emissions. A particulate trap (Diesel Particulate Filter, abbreviated as DPF) is a device installed in the vehicle emission system for capturing and treating particulate emission substances in the exhaust gas generated by the engine.

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

[0033] S1: After the engine stops, obtain the aftertreatment temperature of the engine.

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

[0035] In this embodiment, the aftertreatment temperature can be collected based on the temperature detection elements arranged around the SCR system and the DPF. Specifically, the engine stop can be identified through the engine stop requirement and the stop detection flag bit. After identifying that the engine stops, the corresponding aftertreatment temperature can be obtained by reading the temperature sensor arranged on the aftertreatment system.

[0036] S2: Determine whether to control the urea pump to relieve pressure according to the aftertreatment temperature.

[0037] Among them, the urea pump relieving pressure can be understood as the process of releasing the urea pump pressure to 0; the urea pump not relieving pressure 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 can be compared with the temperature that meets the urea injection condition (i.e., the urea injection temperature), and it is determined whether to control the urea pump to relieve pressure according to the deviation between the post-treatment temperature and the temperature that meets the urea injection condition. Specifically, the urea pump can be controlled to relieve pressure when the post-treatment temperature is low (for example, lower than the urea injection temperature and the temperature difference from the urea injection temperature exceeds 10°C), and the urea pump is controlled not to relieve pressure when the post-treatment temperature is high (for example, lower than the urea injection temperature and the temperature difference from the urea injection temperature is less than 10°C).

[0039] S3: When the urea pump does not relieve pressure, obtain the state of charge of the power battery and the total vehicle demand power of the hybrid vehicle.

[0040] Among them, the state of charge can be understood as a parameter representing the remaining power of the power battery, denoted as SOC. SOC is any value greater than or equal to 0% and less than or equal to 100%. The SOC in the fully charged state of the power battery is 100%, and the SOC when the power battery is completely depleted 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 total vehicle demand power can be understood as the total power that the power system needs to output during the driving or operation of the hybrid vehicle. In this embodiment, the total vehicle demand power provided by the vehicle controller can be obtained in real time through the vehicle communication network, or the total vehicle demand power can be calculated through the throttle opening.

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

[0043] Among them, the urea pump pressure is lower than the injection pressure of the urea pump in the engine operating state.

[0044] In this embodiment, the state of charge and the total vehicle demand power can reflect the demand degree of the vehicle to start the engine. The higher the demand degree of the vehicle to start the engine, the higher the urea pump pressure; the lower the demand degree of the vehicle to start the engine, the lower the urea pump pressure.

[0045] Specifically, after the engine stops, the urea pump does not relieve pressure when the post-treatment temperature is high to ensure that urea can be normally injected after the engine starts. At the same time, the urea pump pressure is controlled according to the state of charge and the total vehicle demand power. When the state of charge of the power battery decreases, or the total vehicle demand power increases, the demand degree of the vehicle to start the engine 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 amount of the urea nozzle and avoid the crystallization of urea in the mixer by controlling a certain urea pump pressure 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 starts, avoiding excessive exhaust emissions. This solves the problem that in the existing frequent start-stop conditions of the engine, the pressure building time is long after the urea injection pressure is relieved, and urea cannot be injected during the pressure building period, resulting in excessive nitrogen oxide emissions, and improves the exhaust gas treatment effect of the hybrid system.

[0047] Figure 2 The figure is a flowchart of a urea pump pressure control method based on the state of charge and the vehicle demand power provided by an embodiment of the present invention. Refer to Figure 2 As shown, in step S4 above, adjusting the urea pump pressure according to the state of charge and the vehicle demand power includes the following steps:

[0048] S401: Obtain the urea pump pressure reference value when the engine is in operation.

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

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

[0051] Among them, the state of charge threshold can be the minimum remaining power of the power battery required to start the engine in the vehicle unloaded state. Exemplarily, the state of charge threshold can be set to 20%.

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

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

[0054] S403: Obtain the vehicle demand power threshold for starting the engine, and determine the second adjustment coefficient according to the vehicle demand power and the vehicle demand power threshold.

[0055] Among them, the vehicle demand power threshold can be the maximum vehicle demand power required to start the engine when the power battery is fully charged (i.e., the state of charge is equal to 100%). Exemplarily, the vehicle demand power threshold can be set to 180 kW.

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

[0057] Exemplarily, if the vehicle's required power is defined as P and the state of charge threshold is P max , then the second adjustment coefficient can be expressed as .

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

[0059] In this embodiment, the urea pump pressure adjustment value can be calculated based on 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 can be 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; the second adjustment coefficient is negatively correlated with the vehicle's required power.

[0061] Specifically, when maintaining the urea pump pressure, adjustments are made based on the state of charge and the vehicle's required power. When the state of charge is low, the torque of the power motor is limited, and the probability of engine startup is relatively 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 decreases, maintaining the urea pump at a relatively high pressure to ensure that urea can be injected as soon as the engine starts. When the vehicle's required power is high, the vehicle may demand engine startup 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's required power is high, the adjustment value decreases, maintaining the urea pump at a relatively high pressure to ensure that urea can be injected as soon as the engine starts.

[0062] Exemplarily, the urea pump pressure demand value can be calculated using the following formula (1):

[0063] (Formula 1)

[0064] Where represents the urea pump pressure demand value; represents the urea pump pressure reference value when the engine is running.

[0065] Thus, the technical solution of this application adapts the adjustment of the urea pump pressure by obtaining the state of charge of the power battery and the vehicle's required power. The adjustment strategy of the urea pump pressure meets the requirements that as the state of charge increases, the required pressure of the urea pump decreases, and as the vehicle's required power 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 amount of the urea nozzle.

[0066] Figure 3It is a flowchart of another urea pump pressure control method provided by an embodiment of the present invention based on the state of charge and the vehicle's required power. Refer to Figure 3 As shown, in the above step S4, adjusting the urea pump pressure according to the state of charge and the vehicle's required power includes:

[0067] S401: Obtain the urea pump pressure reference value when the engine is running.

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

[0069] S403: Obtain the vehicle's required power threshold for starting the engine, and determine the second adjustment coefficient according to the vehicle's required power and the vehicle's required power threshold.

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

[0071] S405: Obtain the current measured value of the urea pump pressure, and calculate the pressure deviation between the current measured value and the urea pump pressure demand value.

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

[0073] Among them, the pressure deviation threshold can be adaptively adjusted based on the pressure value required for the urea pump to maintain normal operation in the engine shutdown state. Exemplarily, the pressure deviation threshold can be set to 1 bar.

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

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

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

[0077] Specifically, when the pressure deviation between the current measured value of the urea pump pressure and the urea pump pressure demand value is greater than or equal to the pressure deviation threshold, execute the urea pump pressure adjustment strategy, and adaptively adjust the urea pump pressure according to the calculated urea pump pressure demand value; when the pressure deviation between the current measured value of the urea pump pressure and the urea pump pressure demand value is less than the pressure deviation threshold, do not execute the urea pump pressure adjustment strategy, and keep the current urea pump pressure unchanged. By monitoring the pressure deviation to adjust the urea pump pressure, it is possible to avoid frequent changes in the urea pump pressure and improve the system stability.

[0078] Figure 4The flowchart of a urea pump pressure relief control method provided by an embodiment of the present invention. Refer to Figure 4 As shown, in the above step S2, determining whether to control the urea pump to relieve pressure according to the post-treatment temperature includes:

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

[0080] Among them, 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. Exemplarily, taking the urea injection temperature of 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 temperature before the SCR upstream of the SCR.

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

[0083] If the temperature before the SCR is less than or equal to the first temperature threshold, then execute step S204; if the temperature before the SCR is greater than the first temperature threshold, then execute step S205.

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

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

[0086] If the temperature before the SCR is greater than or equal to the second temperature threshold, then execute step S206; if the temperature before the SCR is less than the second temperature threshold, then return to continue executing step S202.

[0087] S206: Control the urea pump not to relieve pressure.

[0088] Specifically, after the engine stops, first collect the temperature value measured by the temperature sensor set upstream of the SCR system, denoted as the temperature before the SCR. If the temperature before the SCR is less than or equal to the first temperature threshold t1 (lower than the urea injection temperature, for example, 170 °C), then control the urea pump to relieve pressure so that the urea pump pressure is reduced to 0; if the temperature before the SCR 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), then control the urea pump not to relieve pressure and maintain a certain pressure.

[0089] Figure 5 The flowchart of another urea pump pressure relief control method provided by an embodiment of the present invention. Refer to Figure 5 As shown, in the above step S2, determining whether to control the urea pump to relieve pressure according to the post-treatment temperature includes:

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

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

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

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

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

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

[0096] If the temperature before the SCR is greater than or equal to the second temperature threshold, execute step S206; if the temperature before the SCR is greater than the first temperature threshold and less than the second temperature threshold, return to step S207 and continue to execute.

[0097] S206: Control the urea pump not to relieve pressure.

[0098] S207: Obtain the temperature before the DPF upstream of the particulate filter, and control the urea pump not to relieve pressure when the temperature before the DPF is greater than or equal to the third temperature threshold.

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

[0100] Specifically, after the engine stops, 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 filter is further collected. When the temperature before the DPF is less than the third temperature threshold t3 (higher than the urea injection temperature, such as 190 °C), it indicates that the SCR temperature will not immediately increase after the engine is restarted. At this time, control the urea pump to relieve pressure; when the temperature before the DPF is greater than or equal to the third temperature threshold t3, control the urea pump not to relieve pressure. By monitoring the SCR temperature and the DPF temperature to control the urea pump to relieve pressure, it is possible to quickly build pressure for the urea pump under different working conditions, and avoid excessive nitrogen oxide emissions caused by the inability to inject urea during the period of rebuilding pressure after pressure relief.

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

[0102] S601: After the engine stops, obtain the after-treatment temperature of the engine.

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

[0104] S603: When the urea pump does not release pressure, obtain the state of charge of the power battery and the vehicle demand power of the hybrid vehicle.

[0105] S604: Adjust the urea pump pressure according to the state of charge and the vehicle demand power.

[0106] S605: Obtain the measured value of ammonia storage in the post-treatment system of the engine.

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

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

[0109] Among them, the set value of ammonia storage can be understood as the calibrated value of the ammonia gas storage amount in the SCR carrier under the engine operating state.

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

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

[0112] Specifically, if the measured value of ammonia storage is defined as N a , and the set value of ammonia storage is N d , then the ratio of the measured value of ammonia storage to the set value of ammonia storage 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. The correction coefficient is obtained by querying the preset MAP based on the ratio k. If the correction coefficient is defined as a, and the urea pump pressure demand value calculated based on the state of charge and the vehicle demand power is , then the corrected urea pump pressure can be expressed as . Among them, the corrected urea pump pressure satisfies: greater than 0 and less than or equal to the urea pump pressure reference value of the urea pump under the engine operating state . Thus, 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 7The flowchart of another urea pump pressure control method for a hybrid vehicle provided by an embodiment of the present invention is shown in Figure 7 As shown, the urea pump pressure control method for the hybrid vehicle of the present application includes the following steps:

[0114] S701: After the engine stops, obtain the post-treatment temperature of the engine.

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

[0116] S703: When the urea pump does not relieve pressure, obtain the state of charge of the power battery and the vehicle's total demand power of the hybrid vehicle.

[0117] S704: Adjust the urea pump pressure according to the state of charge and the vehicle's total demand power.

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

[0119] Wherein, the leakage amount threshold is the maximum leakage amount that meets the requirements of the urea nozzle leakage amount.

[0120] Specifically, when the engine stops and the urea pump does not relieve pressure, the urea nozzle leakage amount is monitored in real time, and the urea pump is controlled to relieve pressure when the urea nozzle leakage amount is greater than the leakage amount threshold, so as to avoid the increase of the urea leakage amount caused by the non-relieving of the urea pump and improve the 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 the hybrid vehicle can execute the urea pump pressure control method for the hybrid vehicle provided by any embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing the method.

[0122] Figure 8 The structural schematic diagram of a urea pump pressure control device for a hybrid vehicle provided by an embodiment of the present invention is shown in Figure 8 As shown, the urea pump pressure control device for 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-treatment temperature of the engine after the engine stops; the pressure relief evaluation module 102 is used to determine whether to control the urea pump to relieve pressure according to the post-treatment temperature; the second acquisition module 103 is used to obtain the state of charge of the power battery and the vehicle's total demand power of the hybrid vehicle when the urea pump does not relieve pressure; the control module 104 is used to adjust the urea pump pressure according to the state of charge and the vehicle's total demand power; wherein, the urea pump pressure is lower than the injection pressure of the urea pump in the engine running state.

[0124] Optionally, the control module 104 is configured to: obtain the urea pump pressure reference value when the engine is in operation; obtain the state of charge threshold value for starting the engine, and determine a first adjustment coefficient according to the state of charge and the state of charge threshold value; obtain the vehicle demand power threshold value for starting the engine, and determine a second adjustment coefficient according to the vehicle demand power and the vehicle demand power threshold value; and determine the urea pump pressure demand value according to 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 the current measured value of the urea pump pressure, and calculate the pressure deviation between the current measured value and the urea pump pressure demand value; when the pressure deviation is greater than or equal to the pressure deviation threshold value, adjust the urea pump pressure based on the urea pump pressure demand value; and when the pressure deviation is less than the pressure deviation threshold value, keep the current urea pump pressure unchanged.

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

[0127] Optionally, the after-treatment system of the engine includes an SCR system and a particulate trap. The pressure relief evaluation module 102 of the present application is configured to: obtain a first temperature threshold value and a second temperature threshold value, where the first temperature threshold value is less than the second temperature threshold value, and the second temperature threshold value is less than the urea injection temperature of the after-treatment system; obtain the temperature before SCR upstream of the SCR system; when the temperature before SCR is less than or equal to the first temperature threshold value, control the urea pump to relieve pressure; and when the temperature before SCR is greater than or equal to the second temperature threshold value, control the urea pump not to relieve pressure.

[0128] Optionally, the pressure relief evaluation module 102 of the present application is further configured to: when the temperature before SCR is greater than the first temperature threshold value and less than the second temperature threshold value, obtain the temperature before DPF upstream of the particulate trap, and control the urea pump not to relieve pressure when the temperature before DPF is greater than or equal to a third temperature threshold value; where the third temperature threshold value 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 the measured value of ammonia storage in the after-treatment system of the engine; determine a correction coefficient according to the measured value of ammonia storage and the set value of ammonia storage; and correct the urea pump pressure according to 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 shut down and the urea pump does not relieve pressure, obtain the leakage amount of the urea nozzle of the engine, and control the urea pump to relieve pressure when the leakage amount of the urea nozzle is greater than the leakage amount threshold value.

[0131] Based on the above 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 urea pump pressure control method for the hybrid vehicle as described above.

[0132] Figure 9 FIG. shows a schematic structural diagram of an electronic device 10 that can be used to implement an embodiment of the present invention. 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 processors, 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 claimed herein.

[0133] As Figure 9 shown, the electronic device 10 includes at least one processor 11, and a memory communicatively connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc. Among them, the memory stores a computer program executable by the at least one processor. The processor 11 can execute 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 into 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 plurality 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 magnetic 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 can be various general-purpose and / or special-purpose 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 suitable processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as the urea pump pressure control method for the hybrid vehicle described above.

[0136] In some embodiments, the urea pump pressure control method for the hybrid vehicle described above can be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as the storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed onto 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 can be executed. Alternatively, in other embodiments, the processor 11 can be configured to execute the urea pump pressure control method for the hybrid vehicle described above in any other suitable manner (e.g., by means of firmware).

[0137] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGA), application-specific integrated circuits (ASIC), application-specific standard products (ASSP), system-on-chip systems (SOC), complex programmable logic devices (CPLD), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include: implemented in one or more computer programs, the one or more computer programs can be executed and / or interpreted on a programmable system including at least one programmable processor, the programmable processor can be a dedicated or general-purpose programmable processor, can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit the data and instructions to the storage system, the at least one input device, and the at least one output device.

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

[0139] In the context of the present invention, a computer-readable storage medium can be a tangible medium that can contain or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable storage medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, the computer-readable storage medium can be a machine-readable signal medium. More specific examples of the machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, 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 disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0140] To provide for interaction with a user, the systems and techniques described herein can 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 a trackball) by which the user can provide input to the electronic device. Other kinds of devices can also be used to provide for interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, speech input, or tactile input).

[0141] The systems and techniques described herein can 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 having a graphical user interface or a web browser through which the user can interact with an implementation 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 can 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 far from each other and usually interact via a communication network. The client-server relationship is created by computer programs running on respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or a cloud host, which is a host product in the cloud computing service system, and solves the defects of difficult management and weak business scalability existing in traditional physical hosts and VPS services.

[0143] It should be understood that various forms of processes shown above can be used, steps can be reordered, added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0144] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within 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; Wherein, the urea pump pressure is lower than the injection pressure of the urea pump when the engine is running; The adjusting the urea pump pressure according to the state of charge and the required power of the whole vehicle includes: when the state of charge of the power battery decreases or the required power of the whole vehicle increases, the demand for starting the engine of the vehicle increases, and the higher the demand for starting the engine of the vehicle, the higher the urea pump pressure; the lower the demand for starting the engine of the vehicle, the lower the urea pump pressure, and at the same time, the urea pump pressure is made lower than the urea pump injection pressure; 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.

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: 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.

6. The urea pump pressure control method for a hybrid vehicle according to any one of claims 1 to 5, 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.

7. The urea pump pressure control method for a hybrid vehicle according to any one of claims 1 to 5, 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.

8. 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; Wherein, the urea pump pressure is lower than the injection pressure of the urea pump when the engine is running; The adjusting the urea pump pressure according to the state of charge and the required power of the whole vehicle includes: when the state of charge of the power battery decreases or the required power of the whole vehicle increases, the demand for starting the engine of the vehicle increases, and the higher the demand for starting the engine of the vehicle, the higher the urea pump pressure; the lower the demand for starting the engine of the vehicle, the lower the urea pump pressure, and at the same time, the urea pump pressure is made lower than the urea pump injection pressure; The after-treatment system of the engine includes an SCR system and a particle trap; The determining whether to control the urea pump to release pressure according to the post-treatment temperature includes: acquiring 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; acquiring a pre-SCR temperature upstream of the SCR system; controlling the urea pump to release pressure when the pre-SCR temperature is less than or equal to the first temperature threshold; and controlling the urea pump not to release pressure when the pre-SCR temperature is greater than or equal to the second temperature threshold.

9. 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 7.

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