A transient torque control method and related device for a parallel hybrid system

Abstract

The present application discloses a transient torque control method and related device for a parallel hybrid system, which relates to the technical field of hybrid diesel engines. When the vehicle is in the hybrid mode, the torque demand state of the diesel engine is determined; if the torque demand state is an increase in torque, the operating mode of the diesel engine is obtained, and the torque increase step size of the diesel engine is determined according to the operating mode; the diesel engine is controlled to output torque according to the torque increase step size. In the transient condition of torque increase, the present application can determine the torque increase step size of the diesel engine according to its operating mode, so as to control the diesel engine to output torque, which can make the torque increase step size of the diesel engine adapt to its operating mode, enable the aftertreatment to convert NO x original emissions, and reduce NO x tailpipe peak emissions and avoid exceeding the emission standard.

Description

Technical Field

[0001] The present application relates to the technical field of hybrid diesel engines, and particularly to a transient torque control method and related device for a parallel hybrid system. Background Art

[0002] At present, in the transient condition of torque increase for hybrid diesel vehicles, the output torque of the diesel engine is increased in a fixed step size. If the step size is large, the diesel engine will quickly reach the high-load region, resulting in high NO x raw emissions. Once the temperature of the post-treatment of the diesel engine is low and the ammonia storage is small, the post-treatment cannot convert NO x raw emissions in time, and there will be a NO x tailpipe emission peak, thus causing the emissions to exceed the standard. Summary of the Invention

[0003] In view of the above problems, the present application provides a transient torque control method and related device for a parallel hybrid system to achieve the purpose of reducing the NO x tailpipe emission peak under the transient condition of torque increase. The specific solutions are as follows:

[0004] The first aspect of the present application provides a transient torque control method for a parallel hybrid system, and the transient torque control method for the parallel hybrid system includes:

[0005] When the vehicle is in the hybrid mode, determine the torque demand state of the diesel engine;

[0006] If the torque demand state is torque increase, obtain the working mode of the diesel engine, and determine the torque increase step size of the diesel engine according to the working mode;

[0007] Control the torque output of the diesel engine according to the torque increase step size.

[0008] In a possible implementation, the working mode includes a heating mode, and the determining the torque increase step size of the diesel engine according to the working mode includes:

[0009] Obtain the temperature before SCR, the SCR ammonia storage value, and the NO x raw emission value of the diesel engine;

[0010] Determine a first torque increase rate in the heating mode according to the temperature before SCR and the SCR ammonia storage value, and the first torque increase rate is positively correlated with the temperature before SCR and positively correlated with the SCR ammonia storage value;

[0011] Determine a first correction coefficient matching the NO x raw emission value;

[0012] Calculate the first torque increase step in the heating mode by using the first torque increase rate and the first correction factor.

[0013] In a possible implementation, the operating mode includes a regeneration mode. Determining the torque increase step of the diesel engine according to the operating mode includes:

[0014] Obtain the first excess air coefficient;

[0015] Determine the second torque increase rate in the regeneration mode according to the first excess air coefficient, and the second torque increase rate is positively correlated with the first excess air coefficient;

[0016] Use the second torque increase rate as the second torque increase step in the regeneration mode.

[0017] In a possible implementation, the operating mode includes a normal mode. Determining the torque increase step of the diesel engine according to the operating mode includes:

[0018] Obtain the DPF carbon loading and the second excess air coefficient;

[0019] Determine the third torque increase rate in the normal mode according to the DPF carbon loading and the second excess air coefficient, and the third torque increase rate is negatively correlated with the DPF carbon loading and positively correlated with the second excess air coefficient;

[0020] Use the third torque increase rate as the third torque increase step in the normal mode.

[0021] In a possible implementation, the transient torque control method of the parallel hybrid system further includes:

[0022] If the torque demand state is torque reduction, obtain the intake manifold pressure, the actual intake air flow rate, and the pressure before the supercharger;

[0023] Determine the torque reduction rate according to the intake manifold pressure and the actual intake air flow rate;

[0024] Determine the standard intake air flow rate of the surge line according to the intake manifold pressure and the pressure before the supercharger, and calculate the surge margin by using the actual intake air flow rate and the standard intake air flow rate;

[0025] Determine the second correction factor matching the surge margin, and the second correction factor is positively correlated with the surge margin;

[0026] Calculate the torque reduction step by using the torque reduction rate and the second correction factor;

[0027] Control the diesel engine to output torque according to the torque reduction step size.

[0028] The second aspect of this application provides a transient torque control device for a parallel hybrid system. The transient torque control device for the parallel hybrid system includes:

[0029] A state determination module for determining the torque demand state of the diesel engine when the vehicle is in the hybrid mode;

[0030] A first torque control module for, if the torque demand state is torque increase, obtaining the operating mode of the diesel engine and determining the torque increase step size according to the operating mode; controlling the diesel engine to output torque according to the torque increase step size.

[0031] In a possible implementation, the transient torque control device for the parallel hybrid system further includes:

[0032] A second torque control module for, if the torque demand state is torque reduction, obtaining the intake manifold pressure, the actual intake air flow rate, and the pressure before the supercharger; determining the torque reduction rate according to the intake manifold pressure and the actual intake air flow rate; determining the standard intake air flow rate of the surge line according to the intake manifold pressure and the pressure before the supercharger, and calculating the surge margin using the actual intake air flow rate and the standard intake air flow rate; determining a second correction coefficient that matches the surge margin, the second correction coefficient being positively correlated with the surge margin; calculating the torque reduction step size using the torque reduction rate and the second correction coefficient; controlling the diesel engine to output torque according to the torque reduction step size.

[0033] The third aspect of this application provides a computer program product, including computer-readable instructions that, when running on an electronic device, enable the electronic device to implement the transient torque control method for the parallel hybrid system in the first aspect or any implementation manner of the first aspect.

[0034] The fourth aspect of this application provides an electronic device, including at least one processor and a memory connected to the processor, where:

[0035] The memory is used to store a computer program;

[0036] The processor is used to execute the computer program so that the electronic device can implement the transient torque control method for the parallel hybrid system in the first aspect or any implementation manner of the first aspect.

[0037] The fifth aspect of the present application provides a computer storage medium, which carries one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can implement the transient torque control method of the parallel hybrid system in the first aspect or any implementation manner of the first aspect.

[0038] By means of the above technical solution, a transient torque control method and related device for a parallel hybrid system provided by the present application determine the torque demand state of a diesel engine when the vehicle is in a hybrid mode; if the torque demand state is an increase in torque, obtain the operating mode of the diesel engine, and determine the torque increase step size of the diesel engine according to the operating mode; control the diesel engine to output torque according to the torque increase step size. In the transient condition of torque increase, the present application can determine the torque increase step size of the diesel engine according to its operating mode, so as to control the diesel engine to output torque, which can make the torque increase step size of the diesel engine adapt to its operating mode, enable the post-treatment to convert NO x original emissions, and reduce the NO x tailpipe emission peak to avoid exceeding the emission standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Combined with the drawings and referring to the following specific embodiments, the above and other features, advantages and aspects of the embodiments of the present disclosure will become more obvious. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the original and elements are not necessarily drawn to scale.

[0040] Figure 1 It is a schematic flow chart of a transient torque control method for a parallel hybrid system provided by an embodiment of the present application;

[0041] Figure 2 It is a partial schematic flow chart of a transient torque control method for a parallel hybrid system provided by an embodiment of the present application;

[0042] Figure 3 It is another partial schematic flow chart of a transient torque control method for a parallel hybrid system provided by an embodiment of the present application;

[0043] Figure 4 It is another partial schematic flow chart of a transient torque control method for a parallel hybrid system provided by an embodiment of the present application;

[0044] Figure 5 It is a schematic structural diagram of a transient torque control device for a parallel hybrid system provided by an embodiment of the present application;

[0045] Figure 6 It is a schematic structural diagram of an electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] The embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application. The terms used in the embodiments of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application.

[0047] The embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art will know that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

[0048] The terms "first", "second", etc. in the specification of the present application and the above-mentioned accompanying drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances, which is only a way of distinguishing when describing objects with the same attributes in the embodiments of the present application. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, so that a process, method, system, product or device including a series of units does not have to be limited to those units, but may include other units not clearly listed or inherent to these processes, methods, products or devices.

[0049] In order to reduce the NO x tailpipe peak value when the torque increases, the embodiments of the present application provide a transient torque control method for a parallel hybrid system. The transient torque control method for the parallel hybrid system in the embodiments of the present application will be introduced in detail below with reference to the accompanying drawings.

[0050] For the convenience of understanding the present application, the following explains the relevant concepts involved in the present application:

[0051] SCR (Selective Catalytic Reduction): It is a part of diesel engine aftertreatment and is a treatment process for NO in diesel vehicle exhaust emissions. Ammonia or urea as a reducing agent is injected into the SCR aftertreatment, and under the action of a catalyst, NO in the diesel engine exhaust is x reduced to nitrogen (N x ) and water (H 2 O). 2

[0052] DPF (Diesel Particulate Filter): It is a part of diesel engine aftertreatment and is located after the DOC. The DPF captures particulate matter in the exhaust gas by physical barrier, and these particulate matters accumulate in the filter to form a carbon load. When the carbon load reaches a certain level, the DPF needs to be regenerated to remove these particulate matters.

[0053] DOC (Diesel Oxidation Catalyst): Its main functions are as follows: ① Remove hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas and convert them into harmless carbon dioxide (CO 2 ) and water (H 2 O); ② When the diesel engine enters the regeneration mode, the diesel in the exhaust gas reacts with oxygen inside the DOC to increase the exhaust gas temperature and remove the carbon particles in the DPF aftertreatment.

[0054] NO x : One of the pollutants emitted by diesel engines. More NO is generated when the diesel engine is under high load and needs to be removed through SCR aftertreatment. SCR aftertreatment can convert NO only when the temperature is above 200°C x , and the conversion efficiency is relatively high when the temperature is between 250°C and 350°C. In the SCR, NO x is reduced to N x and O 2 by injecting urea and the ammonia stored inside the SCR (ammonia generated by urea hydrolysis). 2 .

[0055] Surge: A vibration phenomenon under abnormal working conditions that occurs when the intake air flow rate decreases to a certain extent. This vibration phenomenon will cause strong mechanical vibration of the compressor and overheating of the hot end, and cause serious damage to components in a short time. According to the supercharger surge map, the surge risk can be calculated based on the intake air pressure and intake air volume.

[0056] See Figure 1 , Figure 1 is a schematic flowchart of a transient torque control method for a parallel hybrid system provided by an embodiment of the present application. As Figure 1 shown, a transient torque control method for a parallel hybrid system provided by an embodiment of the present application may include steps S10 to S30. These steps will be described in detail below.

[0057] S10. When the vehicle is in the hybrid mode, determine the torque demand state of the diesel engine.

[0058] In the embodiment of the present application, when the vehicle is in the hybrid mode, the vehicle controller determines the vehicle demand torque according to the depth of the accelerator pedal, and then considers the vehicle operating state to allocate the respective demand torques to the motor and the diesel engine, that is, the vehicle demand torque is equal to the motor demand torque and the diesel engine demand torque.

[0059] In this regard, for a diesel engine, its torque demand state can be determined based on its diesel engine demand torque under continuous steps. For example, if the driver suddenly steps on the accelerator, the vehicle's demand torque will increase transiently, which will cause the diesel engine's demand torque to increase transiently. At this time, the diesel engine's torque demand state is torque increase. To continue the example, if the driver releases the accelerator, the vehicle's demand torque will decrease transiently, which will cause the diesel engine's demand torque to decrease transiently. At this time, the diesel engine's torque demand state is torque decrease.

[0060] Of course, when the vehicle is accelerating or climbing, the power demand of the vehicle will be very large. If the accelerator pedal depth is greater than a certain value (such as 80%), the motor demand torque reaches the maximum value of the motor output torque and cannot meet the vehicle demand torque. At this time, in order to give priority to the power output of the vehicle, the diesel engine no longer increases its output torque according to the step length, but outputs according to the diesel engine demand torque.

[0061] S20, if the torque demand state is torque increase, obtain the working mode of the diesel engine, and determine the torque increase step of the diesel engine according to the working mode.

[0062] In the embodiment of the present application, if the torque demand state is torque increase, the working mode of the diesel engine can be determined according to the pre-SCR temperature and the DPF carbon load. Specifically, if the DPF carbon load is high, the working mode is the regeneration mode; if the DPF carbon load is within the normal range and the pre-SCR temperature is low, the working mode is the heating mode, and if the pre-SCR temperature is within the normal range, the working mode is the normal mode.

[0063] Based on this, considering the control objectives of different working modes, the torque increase step of the diesel engine in different working modes can be determined.

[0064] In a possible implementation, when the working mode is heating mode, the temperature before SCR is low, generally below 230°C, and the post-treatment conversion efficiency is low, with emission control as the primary goal. See Figure 2 , Figure 2 is a partial flow chart of a transient torque control method for a parallel hybrid system provided in an embodiment of the present application. Figure 2 As shown, an embodiment of the present application provides a method for controlling transient torque of a parallel hybrid system, wherein the step S20 of "determining the torque increase step of the diesel engine according to the working mode" may include steps S2011 to S2014. These steps are described in detail below.

[0065] S2011, obtain the temperature before SCR, SCR ammonia storage value, and NO of the diesel engine x Original row value.

[0066] ​In the embodiments of the present application, the temperature before SCR and the NO original emission value at the current moment are collected through relevant sensors. In addition, the ammonia storage value of SCR is obtained through the ammonia storage model. x In step S2012, a first torque increase rate in the heating mode is determined according to the temperature before SCR and the ammonia storage value of SCR. The first torque increase rate is positively correlated with the temperature before SCR and positively correlated with the ammonia storage value of SCR.

[0067] The higher the temperature before SCR, the higher the NO conversion efficiency. Therefore, even if the NO original emission is relatively high, it can be converted inside the SCR, so that the NO tail emission is maintained at a relatively low level. The ammonia storage in SCR refers to the amount of ammonia gas present in the form of gas in the gaps inside the SCR. When NO passes through the SCR, ammonia gas will be released inside the SCR to react with NO. The higher the ammonia storage in SCR, the higher the NO conversion efficiency. Therefore, when the temperature before SCR is high and the ammonia storage value of SCR is high, a relatively high NO original emission can be tolerated, and the output torque of the diesel engine can increase at a relatively large rate.

[0068] The higher the temperature before SCR, x the higher the NO conversion efficiency. Therefore, even if the NO x original emission is relatively high, it can be converted inside the SCR, so that the NO x tail emission is maintained at a relatively low level. The ammonia storage in SCR refers to the amount of ammonia gas present in the form of gas in the gaps inside the SCR. When NO x passes through the SCR, ammonia gas will be released inside the SCR to react with NO x The higher the ammonia storage in SCR, x the higher the NO conversion efficiency. Therefore, when the temperature before SCR is high and the ammonia storage value of SCR is high, a relatively high NO x original emission can be tolerated, and the output torque of the diesel engine can increase at a relatively large rate.

[0069] In this regard, in the embodiments of the present application, the torque increase rate corresponding to the temperature before SCR and the ammonia storage value of SCR is determined by means of a look-up table method. This torque increase rate is the first torque increase rate in the heating mode. Specifically, the first torque increase rate is positively correlated with the temperature before SCR, and the first torque increase rate is positively correlated with the ammonia storage value of SCR, that is, the higher the temperature before SCR and the higher the ammonia storage value of SCR, the greater the first torque increase rate. Refer to Table 1, which exemplifies the first torque increase rate corresponding to different temperatures before SCR and ammonia storage values of SCR.

[0070] Table 1

[0071]

[0072] In step S2013, a first correction coefficient matching the NO original emission value is determined. x

[0073] In the embodiments of the present application, when the NO original emission value exceeds a certain value, the first correction coefficient used to correct the first torque increase rate is negatively correlated with the NO original emission value, that is, the higher the NO original emission value, the smaller the first correction coefficient, so as to avoid too high NO tail emission by reducing the NO original emission. The reasons are as follows: x x x x x

[0074] 1) When the NO x conversion efficiency is constant, the higher the original NO x emission, the higher the tailpipe NO x emission. Therefore, when the original NO x emission exceeds a certain value, it is necessary to reduce the torque increase rate of the diesel engine to reduce the high-load operation time of the diesel engine; 2) The higher the original NO x emission, the more urea the SCR needs to inject. Continuous injection of a large amount of urea easily causes incomplete hydrolysis of urea, resulting in urea crystallization at the front end of the SCR, which will cause the SCR conversion efficiency to continuously decrease. See Table 2, which shows the first correction coefficients corresponding to different original NO x emission values.

[0075] Table 2

[0076]

[0077] S2014, calculate the first torque increase step in the heating mode using the first torque increase rate and the first correction coefficient.

[0078] In the embodiments of the present application, the product of the first torque increase rate and the first correction coefficient can be used as the torque increase step in the heating mode, that is, the first torque increase step.

[0079] In a possible implementation, when the working mode is the regeneration mode, since sufficient oxygen is required, the problem of slow regeneration rate caused by too low oxygen concentration during regeneration can be avoided by controlling the torque increase step. See Figure 3 , Figure 3 which is another part of the flowchart of the transient torque control method for a parallel hybrid system provided by the embodiments of the present application. As Figure 3 shown, for the transient torque control method for a parallel hybrid system provided by the embodiments of the present application, in step S20, "determine the torque increase step of the diesel engine according to the working mode", which may include steps S2021 to S2023. These steps will be described in detail below.

[0080] S2021, obtain the first excess air coefficient.

[0081] In the regeneration mode, the diesel engine injects fuel into the cylinder during the exhaust stroke and needs to burn with the oxygen in the exhaust gas in the aftertreatment. If the excess air coefficient in the intake air is too small, it will cause a decrease in the oxygen content in the exhaust gas, and the diesel in the exhaust gas cannot obtain sufficient oxygen for combustion, and the aftertreatment cannot obtain sufficient temperature, resulting in slow DPF aftertreatment regeneration. In this regard, when the excess air coefficient is low, the increase amplitude of the fuel injection amount can be reduced by restricting the torque increase step to maintain sufficient oxygen in the exhaust gas.

[0082] In the embodiments of the present application, the excess air coefficient at the current moment, i.e., the first excess air coefficient, can be calculated based on the intake air flow rate and the fuel injection amount. Specifically, the excess air coefficient = intake air flow rate / fuel injection amount / 14.3 (1 kg of diesel requires 14.3 kg of air for complete combustion). When the excess air coefficient is 1, the diesel and air ejected at this time can react completely. However, due to the poor atomization of diesel in the diesel engine cylinder, there is a situation of local air shortage. Therefore, the excess air coefficient of the diesel engine is generally greater than 1.

[0083] S2022. Determine the second torque increase rate in the regeneration mode according to the first excess air coefficient. The second torque increase rate is positively correlated with the first excess air coefficient.

[0084] In the embodiments of the present application, the torque increase rate corresponding to the first excess air coefficient is determined by the look-up table method, and this torque increase rate is the second torque increase rate in the regeneration mode. Specifically, the second torque increase rate is positively correlated with the first excess air coefficient, that is, the higher the first excess air coefficient, the greater the second torque increase rate. Refer to Table 3, which shows the second torque increase rates corresponding to different first excess air coefficients.

[0085] Table 3

[0086]

[0087] S2023. Use the second torque increase rate as the second torque increase step in the regeneration mode.

[0088] In the embodiments of the present application, the second torque increase rate is used as the torque increase step in the regeneration mode, that is, the second torque increase step.

[0089] In a possible implementation, when the working mode is the normal mode, the temperature before the SCR is relatively high, and the NO x conversion efficiency is high. The transient working condition aims to control the smoke density. Refer to Figure 4 , Figure 4 which is another part of the flow schematic diagram of the transient torque control method for a parallel hybrid system provided by the embodiments of the present application. As Figure 4 shown, for the transient torque control method for a parallel hybrid system provided by the embodiments of the present application, in step S20, "determine the torque increase step of the diesel engine according to the working mode", it may include steps S2031 to S2033. These steps will be described in detail below.

[0090] S2031. Obtain the DPF carbon loading and the second excess air coefficient.

[0091] During the combustion process of a diesel engine, the smaller the excess air coefficient, the worse the combustion, and it is easy to generate more soot. Therefore, when the excess air coefficient is small, the torque increase in the transient condition is slow, so that the fuel injection amount can be increased slowly to minimize the generation of soot. On the contrary, when the excess air coefficient is large, it means that the intake air is sufficient and the torque can be increased in larger steps, and there will be no excessive soot at this time. In addition, the DPF soot loading reflects the degree of soot accumulation in the DPF aftertreatment. When the DPF soot loading is high, the torque increase amplitude needs to be slowed down to prevent the rapid increase in torque from resulting in a high soot value and causing the DPF soot loading to increase too quickly, triggering the regeneration mode. During the regeneration mode, additional diesel needs to be injected into the cylinder of the diesel engine and enter the aftertreatment with the exhaust gas, where it burns with the oxygen in the exhaust gas in the DOC aftertreatment to generate high temperature (about 600 °C), burning the soot trapped in the DPF aftertreatment. This process will lead to an increase in the vehicle fuel consumption. To address this, the present application reduces the transient soot during the torque increase process to prevent the DPF aftertreatment soot loading from increasing too quickly, and delays the time to enter the regeneration mode as much as possible to reduce the vehicle fuel consumption.

[0092] In the embodiments of the present application, the DPF soot loading can be obtained through an internal soot loading model. In addition, the excess air coefficient at the current moment, i.e., the second excess air coefficient, is calculated based on the intake air flow rate and the fuel injection amount.

[0093] S2032. Determine the third torque increase rate in the normal mode according to the DPF soot loading and the second excess air coefficient. The third torque increase rate is negatively correlated with the DPF soot loading and positively correlated with the second excess air coefficient.

[0094] In the embodiments of the present application, the torque increase rate corresponding to the DPF soot loading and the second excess air coefficient is determined by a look-up table method, and this torque increase rate is the third torque increase rate in the normal mode. Specifically, the third torque increase rate is negatively correlated with the DPF soot loading and positively correlated with the second excess air coefficient, that is, the higher the DPF soot loading, the smaller the third torque increase rate, and the higher the second excess air coefficient, the larger the third torque increase rate. Refer to Table 4, which shows the third torque increase rates corresponding to different DPF soot loadings and second excess air coefficients as an example.

[0095] Table 4

[0096]

[0097] S2033. Use the third torque increase rate as the third torque increase step in the normal mode.

[0098] In the embodiments of the present application, the third torque increase rate is used as the torque increase step in the normal mode, that is, the third torque increase step.

[0099] S30, control the diesel engine to output torque according to the torque increase step size.

[0100] In the embodiment of the present application, after obtaining the torque increase step size, the output torque of the diesel engine at the current step size can be calculated. Specifically, assume that the torque increase step size is △T1 and the output torque of the diesel engine at the previous step size is T1 -1 , then the output torque T1 of the diesel engine at the current step size is T1 -1 + △T1. Of course, in actual applications, when controlling the diesel engine to output torque, the smaller value between the output torque T1 at the current step size and the required torque of the diesel engine can be taken for output.

[0101] In a possible implementation, when the torque decreases, the diesel engine instantly stops fuel injection, the intake air volume instantly decreases, and the turbocharger turbine shaft cannot respond immediately due to inertia, causing the turbocharger speed and boost ratio to remain unchanged for a certain period of time. Reflected on the turbocharger surge map, it runs from right to left, approaching a horizontal line, and will quickly approach the surge line. If the diesel engine torque drops too fast, it will exceed the surge line, resulting in turbocharger surge. To avoid turbocharger surge when the diesel engine torque drops and improve the transient performance of the diesel engine, the embodiment of the present application sets the torque reduction rate according to the turbocharger surge map. For this, a transient torque control method for a parallel hybrid system provided by the embodiment of the present application further includes the following steps:

[0102] If the torque demand state is torque reduction, obtain the intake manifold pressure, actual intake air flow, and pressure before the turbocharger; determine the torque reduction rate according to the intake manifold pressure and actual intake air flow; determine the standard intake air flow of the surge line based on the intake manifold pressure and pressure before the turbocharger, and calculate the surge margin using the actual intake air flow and the standard intake air flow; determine the second correction coefficient matching the surge margin, and the second correction coefficient is positively correlated with the surge margin; calculate the torque reduction step size using the torque reduction rate and the second correction coefficient; control the diesel engine to output torque according to the torque reduction step size.

[0103] In the embodiment of the present application, if the torque demand state is torque reduction, the intake manifold pressure, the actual intake air flow rate, and the pressure before the supercharger are obtained through relevant sensors. On the one hand, the torque reduction rate corresponding to the intake manifold pressure and the actual intake air flow rate is determined by the look-up table method. On the other hand, the ratio of the intake manifold pressure to the pressure before the supercharger is used as the boost ratio, and the intake air flow rate of the surge line is determined by querying the supercharger surge map with this boost ratio, that is, the standard intake air flow rate. Furthermore, the surge margin is calculated using the actual intake air flow rate and the standard intake air flow rate. The surge margin = (actual intake air flow rate - standard intake air flow rate) / standard intake air flow rate. Further, the second correction coefficient corresponding to the surge margin for correcting the torque reduction rate is determined by the look-up table method. This second correction coefficient is positively correlated with the surge margin, that is, the larger the surge margin, the larger the second correction coefficient. Refer to Table 5, which shows the second correction coefficients corresponding to different surge margins as an example.

[0104] Table 5

[0105]

[0106] Furthermore, the product of the torque reduction rate and the second correction coefficient is used as the torque reduction step, and the output torque of the diesel engine at the current step is calculated with this torque reduction step.

[0107] Specifically, assume that the torque reduction step is △T2 and the output torque of the diesel engine at the previous step is T2 -1 , then the output torque T2 of the diesel engine at the current step is T2 -1 + △T2.

[0108] Through the above description, a transient torque control method for a parallel hybrid system provided by an embodiment of the present application can, on the one hand, reduce the NO x tailpipe emission peak under transient conditions and avoid exceeding the emission standard; on the other hand, it can reduce the smoke emission peak under transient conditions and prevent excessive carbon deposition; on the other hand, it can avoid regeneration interruption; and on the other hand, it can avoid supercharger surge.

[0109] The above introduced a transient torque control method for a parallel hybrid system provided by an embodiment of the present application. Next, the device for implementing the above transient torque control method of the parallel hybrid system will be introduced.

[0110] Refer to Figure 5 , Figure 5 which is a schematic structural diagram of a transient torque control device for a parallel hybrid system provided by an embodiment of the present application. As Figure 5 shown, a transient torque control device for a parallel hybrid system provided by an embodiment of the present application includes:

[0111] A state determination module 10, configured to determine the torque demand state of the diesel engine when the vehicle is in the hybrid mode;

[0112] The first torque control module 20 is configured to, if the torque demand state is torque increase, obtain the operating mode of the diesel engine and determine the torque increase step of the diesel engine according to the operating mode; control the diesel engine to output torque according to the torque increase step.

[0113] In a possible implementation, the operating mode includes a heating mode. The first torque control module 20 for determining the torque increase step of the diesel engine according to the operating mode is specifically configured to:

[0114] Obtain the temperature before SCR, the ammonia storage value of SCR, and the NO x original emission value of the diesel engine; determine the first torque increase rate in the heating mode according to the temperature before SCR and the ammonia storage value of SCR, and the first torque increase rate is positively correlated with the temperature before SCR and positively correlated with the ammonia storage value of SCR; determine the first correction coefficient matching the NO x original emission value; calculate the first torque increase step in the heating mode by using the first torque increase rate and the first correction coefficient.

[0115] In a possible implementation, the operating mode includes a regeneration mode. The first torque control module 20 for determining the torque increase step of the diesel engine according to the operating mode is specifically configured to:

[0116] Obtain the first excess air coefficient; determine the second torque increase rate in the regeneration mode according to the first excess air coefficient, and the second torque increase rate is positively correlated with the first excess air coefficient; use the second torque increase rate as the second torque increase step in the regeneration mode.

[0117] In a possible implementation, the operating mode includes a normal mode. The first torque control module 20 for determining the torque increase step of the diesel engine according to the operating mode is specifically configured to:

[0118] Obtain the DPF carbon loading and the second excess air coefficient; determine the third torque increase rate in the normal mode according to the DPF carbon loading and the second excess air coefficient, and the third torque increase rate is negatively correlated with the DPF carbon loading and positively correlated with the second excess air coefficient; use the third torque increase rate as the third torque increase step in the normal mode.

[0119] In a possible implementation, the transient torque control device of the above parallel hybrid system further includes:

[0120] A second torque control module, configured to, if the torque demand state is torque reduction, obtain the intake manifold pressure, the actual intake air flow rate, and the pressure before the supercharger; determine the torque reduction rate according to the intake manifold pressure and the actual intake air flow rate; determine the standard intake air flow rate of the surge line based on the intake manifold pressure and the pressure before the supercharger, and calculate the surge margin using the actual intake air flow rate and the standard intake air flow rate; determine a second correction coefficient that matches the surge margin, where the second correction coefficient is positively correlated with the surge margin; calculate the torque reduction step using the torque reduction rate and the second correction coefficient; and control the diesel engine to output torque according to the torque reduction step.

[0121] It should be noted that for the detailed functions of each module in the embodiments of the present application, reference may be made to the corresponding publicly disclosed parts in the embodiments of the transient torque control method for the parallel hybrid system described above, which will not be elaborated herein.

[0122] An electronic device is also provided in the embodiments of the present application. Refer to Figure 6 , Figure 6 which is a schematic structural diagram of an electronic device provided in the embodiments of the present application. The electronic device in the embodiments of the present application may include, but is not limited to, fixed terminals such as mobile phones, laptop computers, PDAs (Personal Digital Assistants), PADs (Tablet Computers), desktop computers, and the like. Figure 6 The electronic device shown is merely an example and should not impose any limitation on the functions and usage scope of the embodiments of the present application.

[0123] As Figure 6 shown, the electronic device may include a processing device (such as a central processing unit, a graphics processing unit, etc.) 601, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 602 or the program loaded from the storage device 608 into the random access memory (RAM) 603. When the electronic device is powered on, various programs and data required for the operation of the electronic device are also stored in the RAM 603. The processing device 601, the ROM 602, and the RAM 603 are connected to each other through a bus 604. The input / output (I / O) interface 605 is also connected to the bus 604.

[0124] Generally, the following devices may be connected to the I / O interface 605: an input device 606 including, for example, a touch screen, a touchpad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; an output device 607 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 608 including, for example, a memory card, a hard disk, etc.; and a communication device 609. The communication device 609 can allow the electronic device to communicate with other devices wirelessly or wiredly to exchange data. Although Figure 6An electronic device having various devices is shown, but it should be understood that it is not required to implement or have all the shown devices. Instead, more or fewer devices may be implemented or had.

[0125] An embodiment of the present application also provides a computer program product including computer-readable instructions, which, when running on an electronic device, enable the electronic device to implement any transient torque control method of the parallel hybrid system provided by the embodiments of the present application.

[0126] An embodiment of the present application also provides a computer-readable storage medium carrying one or more computer programs, which, when executed by an electronic device, can enable the electronic device to implement any transient torque control method of the parallel hybrid system provided by the embodiments of the present application.

[0127] In addition, it should be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the drawings of the device embodiments provided by the present application, the connection relationships between the modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines.

[0128] Through the description of the above embodiments, those skilled in the art can clearly understand that the present application can be implemented by means of software plus necessary general hardware, and of course, it can also be implemented by dedicated hardware including application-specific integrated circuits, dedicated CPUs, dedicated memories, dedicated components, etc. Generally, functions completed by computer programs can be easily implemented by corresponding hardware, and the specific hardware structures for implementing the same function can also be various, such as analog circuits, digital circuits or dedicated circuits. However, for the present application, in more cases, software program implementation is a better implementation method. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a readable storage medium, such as a floppy disk, USB flash drive, mobile hard disk, ROM, RAM, magnetic disk or optical disc of a computer, including several instructions for enabling a computer device (which can be a personal computer, training device, or network device, etc.) to execute the methods described in the various embodiments of the present application.

[0129] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product.

[0130] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, training device, or data center to another website, computer, training device, or data center by wire (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can store or a data storage device such as a training device or data center that includes one or more integrated available media. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium (for example, a solid state disk (SSD)), etc.

Claims

1. A method for transient torque control of a parallel hybrid system, characterized in that: The transient torque control method of the parallel hybrid system includes: When the vehicle is in hybrid mode, determine the torque demand state of the diesel engine; If the torque demand state is torque increase, obtaining the working mode of the diesel engine, and determining the torque increase step length of the diesel engine according to the working mode; controlling the diesel engine to output torque according to the torque increase step; Wherein, the working mode includes a heating mode, and determining the torque increase step of the diesel engine according to the working mode includes: Obtain the temperature before SCR, the SCR ammonia storage value, and the NO x Original row value; determining a first torque increase rate in the heating mode according to the pre-SCR temperature and the SCR ammonia storage value, wherein the first torque increase rate is positively correlated with the pre-SCR temperature and the SCR ammonia storage value; Determine the NO x The first correction factor that matches the original row value; calculating a first torque increase step length in the heating mode by using the first torque increase rate and the first correction coefficient; Wherein, the working mode includes a regeneration mode, and determining the torque increase step of the diesel engine according to the working mode includes: Obtaining a first excess air coefficient; determining a second torque increase rate in the regeneration mode according to the first excess air coefficient, wherein the second torque increase rate is positively correlated with the first excess air coefficient; using the second torque increase rate as a second torque increase step length in the regeneration mode; Wherein, the working mode includes a normal mode, and determining the torque increase step of the diesel engine according to the working mode includes: Obtaining DPF carbon load and second excess air coefficient; determining a third torque increase rate in the normal mode according to the DPF carbon load and the second excess air coefficient, wherein the third torque increase rate is negatively correlated with the DPF carbon load and positively correlated with the second excess air coefficient; The third torque increase rate is used as a third torque increase step size in the normal mode.

2. The method for controlling the transient torque of a parallel hybrid system according to claim 1, characterized in that: The transient torque control method of the parallel hybrid system further includes: If the torque demand state is torque reduction, obtaining intake manifold pressure, actual intake air flow rate and pressure before the supercharger; determining a torque reduction rate according to the intake manifold pressure and the actual intake air flow rate; Determining a standard intake flow rate of a surge line according to the intake manifold pressure and the pressure before the supercharger, and calculating a surge margin using the actual intake flow rate and the standard intake flow rate; determining a second correction coefficient matching the surge margin, wherein the second correction coefficient is positively correlated with the surge margin; calculating a torque reduction step length using the torque reduction rate and the second correction coefficient; The diesel engine is controlled to output torque according to the torque reduction step.

3. A transient torque control device for a parallel hybrid system, characterized in that: The transient torque control device of the parallel hybrid system comprises: A state determination module, used to determine the torque demand state of the diesel engine when the vehicle is in a hybrid mode; a first torque control module, configured to obtain a working mode of the diesel engine if the torque demand state is torque increase, and determine a torque increase step length of the diesel engine according to the working mode; and control the diesel engine to output torque according to the torque increase step length; Wherein, the working mode includes a heating mode, and the first torque control module for determining the torque increase step length of the diesel engine according to the working mode is specifically used for: Obtain the temperature before SCR, the SCR ammonia storage value, and the NO x original exhaust value; determining the first torque increase rate in the heating mode according to the pre-SCR temperature and the SCR ammonia storage value, the first torque increase rate being positively correlated with the pre-SCR temperature and the SCR ammonia storage value; determining the NO x a first correction coefficient that matches the original displacement value; and calculating a first torque increase step length in the heating mode using the first torque increase rate and the first correction coefficient; Wherein, the working mode includes a regeneration mode, and the first torque control module for determining the torque increase step length of the diesel engine according to the working mode is specifically used for: Acquire a first excess air coefficient; determine a second torque increase rate in the regeneration mode according to the first excess air coefficient, wherein the second torque increase rate is positively correlated with the first excess air coefficient; and use the second torque increase rate as a second torque increase step in the regeneration mode; The working mode includes a normal mode, and the first torque control module for determining the torque increase step length of the diesel engine according to the working mode is specifically used for: Acquire the DPF carbon load and the second excess air coefficient; determine a third torque increase rate in the normal mode according to the DPF carbon load and the second excess air coefficient, wherein the third torque increase rate is negatively correlated with the DPF carbon load and positively correlated with the second excess air coefficient; and use the third torque increase rate as the third torque increase step in the normal mode.

4. The transient torque control device of the parallel hybrid system according to claim 3, characterized in that: The transient torque control device of the parallel hybrid system further includes: The second torque control module is used to obtain the intake manifold pressure, the actual intake flow rate and the pressure before the supercharger if the torque demand state is torque reduction; determine the torque reduction rate according to the intake manifold pressure and the actual intake flow rate; determine the standard intake flow rate of the surge line according to the intake manifold pressure and the pressure before the supercharger, and calculate the surge margin using the actual intake flow rate and the standard intake flow rate; determine a second correction coefficient that matches the surge margin, the second correction coefficient is positively correlated with the surge margin; calculate the torque reduction step length using the torque reduction rate and the second correction coefficient; and control the diesel engine to output torque according to the torque reduction step length.

5. A computer program product, characterized in that The method comprises computer-readable instructions, and when the computer-readable instructions are executed on an electronic device, the electronic device implements the transient torque control method of a parallel hybrid system as claimed in any one of claims 1 to 2.

6. An electronic device, characterized in that: The method comprises at least one processor and a memory connected to the processor, wherein: The memory is used to store computer programs; The processor is used to execute the computer program so that the electronic device can implement the transient torque control method of the parallel hybrid system as described in any one of claims 1 to 2.

7. A computer storage medium, characterized in that: The storage medium carries one or more computer programs, and when the one or more computer programs are executed by an electronic device, the electronic device can implement the transient torque control method of the parallel hybrid system as described in any one of claims 1 to 2.

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