Model control mode for different carbon loading capacities of GPF for gasoline vehicle exhaust aftertreatment

Abstract

The invention discloses a gasoline car exhaust aftertreatment GPF carbon load different model control mode, which comprises the following specific steps: step 1, establishing a carbon load model including a soot accumulation model and a soot regeneration model; step 2, testing and calibrating a carbon loading capacity model, including rack calibration and whole vehicle verification and calibration; step 3, a regeneration strategy including passive regeneration and active regeneration; the invention relates to the technical field of GPF carbon loading capacity treatment. According to the different model control modes of the GPF carbon loading capacity for gasoline vehicle exhaust aftertreatment, GPF regeneration is controlled through a GPF carbon loading capacity model, the model value of the GPF carbon loading capacity is higher than the current actual carbon loading capacity so that the GPF can enter the regeneration process earlier, GPF blockage can be prevented, in order to accurately estimate and calculate the GPF carbon loading capacity, a new model processing mode is further added, and the GPF carbon loading capacity can be accurately estimated and calculated. And regeneration of the GPF is better realized.

Description

Technical Field

[0001] The present invention relates to the technical field of GPF carbon load processing, and in particular to a control method for different models of GPF carbon load after-treatment of gasoline vehicle exhaust. Background Art

[0002] The technical route of the National VI post-treatment of gasoline vehicles is a gradual and incremental process, requiring automobile manufacturers to make coordinated improvements in combustion control, three-way catalysis and GPF to achieve higher purification effects and more stringent emission standards. The technical route of the National VI post-treatment of gasoline engines In recent years, with the increasing prominence of the world energy crisis, environmental protection concerns have continued to increase. In order to reduce the pollution of automobile exhaust to the environment, my country began to implement the National VI emission standards on July 1, 2019. The technical route of the National VI post-treatment of gasoline vehicles mainly includes three parts: combustion control technology, three-way catalysis and GPF filter. First of all, combustion control technology is one of the key technologies in modern automobile engine control systems, which is crucial to reducing pollution emissions. By controlling the combustion of the engine, the generation of harmful substances in the combustion products can be reduced, thereby reducing the pollution of exhaust gas.

[0003] The existing technology has the following deficiencies: 1. Because GPF increases exhaust resistance, carbon particles will be deposited on GPF over time, and the resistance will increase further. However, GPF is designed to have self-recovery capabilities. When the temperature is higher than 540 degrees, GPF will undergo a chemical reaction to consume the deposited carbon particles. As the National VI models are widely rolled out in the market, the "symptoms" of gasoline engine particulate filters (GPFs) have begun to appear. When cars are driving in urban areas with dense traffic, the engine maintains low speed operation for a long time, which is not conducive to the full combustion of fuel, and GPF cannot meet the working conditions of active regeneration, causing particulate matter to be in a state of complete accumulation, causing the exhaust back pressure to rise, aggravating the blockage of the particle filter, resulting in a series of problems such as vehicle exhaust failure, soaring fuel consumption, reduced power, failure of the vehicle start-stop function, and gear shifting frustration. Even the ceramic structure of the GPF may crack or be completely damaged. Each GPF gasoline engine particulate filter, regardless of the material used in its design, must be cleaned and emptied regularly so that there is room to continue to collect more particulate matter. This process of cleaning and emptying the GPF is called GPF regeneration, which is to secondary burn the carbon particles collected in the GPF gasoline engine particulate filter to ensure that the filter will not be blocked and can continue to capture more carbon particles for recycling. One of the best ways to solve the blockage is to regenerate the GPF, but during the GPF regeneration process, it is usually necessary to increase the temperature in the GPF by increasing the exhaust gas temperature so that the particulate matter burns. This temperature generally reaches more than 600°C. This is difficult to do under urban driving conditions that require low energy consumption (fuel consumption). When driving very short distances or low loads, the accumulated particulate matter will not burn. For low-load driving of the vehicle, the exhaust temperature is low and the GPF carbon particles increase. The vehicle controller needs to add a GPF regeneration control model to achieve GPF regeneration and prevent GPF blockage. Summary of the invention

[0004] 1. Technical issues to be resolved In view of the deficiencies of the prior art, the present invention provides a control method for different models of carbon load of GPF for exhaust aftertreatment of gasoline vehicles, which solves the problems mentioned in the above background technology.

[0005] (II) Technical solution To achieve the above objectives, the present invention is implemented through the following technical solutions: a control method for different models of carbon load of GPF for exhaust aftertreatment of gasoline vehicles, including the following specific steps: Step 1: Establishing a carbon load model, including a soot accumulation model and a soot regeneration model; Step 2: Carbon load model test and calibration, including bench calibration, vehicle verification and calibration; Step 3: Regeneration strategy, including passive regeneration and active regeneration.

[0006] Preferably, the method for establishing the carbon soot accumulation model is as follows: input parameters of engine speed and load to obtain the basic pulse spectrum of the carbon soot accumulation model; the air-fuel ratio is used to make air-fuel ratio correction to the basic pulse spectrum, the engine starting water temperature and running time are used for starting correction; the load change rate is used for transient operating condition correction; the current water temperature of the engine is used for water temperature correction.

[0007] Preferably, the method for establishing the soot regeneration model is: inputting parameters of the current GPF carbon load, GPF internal temperature and exhaust oxygen flow, distinguishing between active regeneration and passive regeneration conditions, and establishing an open-loop regeneration model.

[0008] Preferably, in the step 1, the real-time numerical values ​​of the carbon accumulation model and the regeneration model are subtracted and input into the accumulation calculator, so as to obtain the model carbon load accumulated by the GPF at the current moment.

[0009] Preferably, in step three, the regeneration process is carried out under oxygen-rich and high temperature (>600° C.) conditions.

[0010] Preferably, in the active regeneration: when the GPF temperature is less than 600°C and the carbon load of the GPF is greater than the set limit of 50%, the engine control system will trigger an active regeneration request, delay the ignition angle to increase the exhaust temperature to further heat the GPF; when the GPF temperature is between 600°C and 650°C and the carbon load of the GPF is greater than the set limit (50%), the engine control system will trigger an active regeneration request, delay the ignition angle to increase the exhaust temperature to heat the GPF, and adopt a lean air-fuel ratio to form a high-temperature and oxygen-rich environment inside the GPF; when the GPF temperature is greater than 750°C, the engine needs to enter the component protection mode and the active regeneration exits; when the GPF carbon load is greater than 150%, in order to prevent the GPF itself from being damaged during the regeneration process, the regeneration process of the GPF is usually prohibited, and the GPF needs to be processed or replaced at the after-sales service.

[0011] Preferably, the passive regeneration process is: when the car suddenly releases the accelerator pedal to slow down during high-speed driving, the engine throttle will quickly close from a larger opening position to an idle position, and the amount of fresh air entering the cylinder will be reduced. In order to avoid incomplete combustion caused by excessively rich mixers and improve fuel economy and emissions, the engine is usually interrupted from injecting fuel. At this time, the engine will rotate at a high speed under the action of the inertia force of the vehicle, and the vehicle has no power request until the engine speed drops to the set speed or the throttle is reopened (the driver steps on the accelerator pedal again) before resuming the fuel supply, that is, the deceleration and oil-cutting process; during the deceleration and oil-cutting process, the oxygen flow in the exhaust gas increases significantly. If the GPF temperature reaches the regeneration requirement at this time, the particulate matter in the GPF can be quickly burned. In the actual application of the vehicle post-processing GPF, the carbon load in the GPF cannot be directly measured, and can only be calculated and estimated through the model, so a high requirement is placed on the accuracy of the carbon load model. When the GPF carbon load model value is lower than the actual value, the GPF active regeneration cycle will be prolonged, the particulate matter will continue to accumulate and cause the GPF to be blocked, and the engine fuel economy will deteriorate.

[0012] (III) Beneficial effects The present invention provides a control method for different models of carbon load of GPF for aftertreatment of gasoline vehicle exhaust. Compared with the prior art, it has the following beneficial effects: the control method for different models of carbon load of GPF for aftertreatment of gasoline vehicle exhaust controls GPF regeneration through the model of GPF carbon load, and the model value of GPF carbon load is higher than the current actual carbon load, so as to enter the regeneration process earlier and prevent GPF from being blocked. In order to accurately estimate and calculate the carbon load of GPF, the present invention also adds a new model processing method to better realize the regeneration of GPF. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The present invention provides a soot accumulation model and a soot regeneration model for different model control modes of the GPF carbon load of gasoline vehicle exhaust aftertreatment; Figure 2 The present invention provides a regeneration process condition for different model control methods of the GPF carbon load of gasoline vehicle exhaust aftertreatment; Figure 3 The Soot original exhaust model provided by the present invention for different model control modes of the GPF carbon load of gasoline vehicle exhaust aftertreatment; Figure 4 The NO2 model operating cycle information provided by the present invention for different model control modes of the GPF carbon load of the exhaust aftertreatment of gasoline vehicles; Figure 5 The test results of the pressure difference protection provided by the present invention for different model control modes of the GPF carbon load of the exhaust aftertreatment of gasoline vehicles; Figure 6 The Soot combustion model provided by the present invention for different model control modes of the GPF carbon load of the exhaust aftertreatment of gasoline vehicles; Figure 7 The present invention provides a Soot burning model for different model control methods of the GPF carbon load of gasoline vehicle exhaust aftertreatment. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Example 1 A control method for different models of carbon load of GPF for exhaust aftertreatment of gasoline vehicles includes the following specific steps: Step 1: Establish a carbon load model, including a soot accumulation model and a soot regeneration model. Subtract the real-time values ​​of the soot accumulation model and the regeneration model and input them into the accumulation calculator to obtain the model carbon load accumulated by the GPF at the current moment. The method for establishing the soot accumulation model is as follows: the input parameters of engine speed and load are used to obtain the basic pulse spectrum of the soot accumulation model; the air-fuel ratio is used to make air-fuel ratio corrections to the basic pulse spectrum, the engine starting water temperature and running time are used for starting corrections; the load change rate is used for transient operating condition corrections; the current engine water temperature is used for water temperature corrections; The method for establishing the soot regeneration model is as follows: input parameters of the current GPF carbon load, GPF internal temperature and exhaust oxygen flow, distinguish between active regeneration and passive regeneration conditions, and establish an open-loop regeneration model; Step 2: Carbon load model test and calibration, including bench calibration, vehicle verification and calibration; Among them, the bench calibration includes Soot original exhaust model, H02 model, pressure difference model and Soot combustion model; Step 3: Regeneration strategy, including passive regeneration and active regeneration. The regeneration process is carried out under oxygen-rich and high temperature (>600°C) conditions; Table 1 Soot original row model cycle results Table 2 NO2 model test results Table 3 Soot combustion model Table 4 Verification results of Soot original row model In summary, the maximum T4 exhaust temperature is 221°C, and it is believed that there is no CRT reaction; this part is used to verify the soot original exhaust model.

[0016] Table 5 CRT model verification In summary, the vehicle cycle of the CRT model traverses the exhaust temperature range of 30~403degC and the carbon loading range of 4.3-17.4g.

[0017] During active regeneration: When the GPF temperature is less than 600°C and the GPF carbon load is greater than the set limit of 50%, the engine control system will trigger an active regeneration request, delay the ignition angle to increase the exhaust temperature and further heat the GPF; when the GPF temperature is between 600°C and 650°C and the GPF carbon load is greater than the set limit (50%), the engine control system will trigger an active regeneration request, delay the ignition angle to increase the exhaust temperature to heat the GPF, and use a lean air-fuel ratio to form a high-temperature, oxygen-rich environment inside the GPF; when the GPF temperature is greater than 750°C, the engine needs to enter the component protection mode and active regeneration will exit; when the GPF carbon load is greater than 150%, the GPF regeneration process is usually prohibited to prevent the GPF itself from being damaged during the regeneration process, and the GPF needs to be processed or replaced by after-sales service; The passive regeneration process is as follows: when the car suddenly releases the accelerator pedal to slow down while driving at high speed, the engine throttle will quickly close from a larger opening position to the idle position, and the amount of fresh air entering the cylinder will be reduced. In order to avoid incomplete combustion caused by excessive mixture, and to improve fuel economy and emissions, the engine is usually interrupted from fuel injection. At this time, the engine will rotate at high speed under the action of the vehicle's inertia force, and the vehicle has no power request until the engine speed drops to the set speed or the throttle is reopened (the driver steps on the accelerator pedal again) before resuming fuel supply, which is the deceleration and fuel cut-off process. During the deceleration and fuel cut-off process, the oxygen flow in the exhaust gas increases significantly. If the GPF temperature reaches the regeneration requirements at this time, the particulate matter in the GPF can be quickly burned off.

[0018] like Figure 5 As shown, a carbon loading of 23.9 g corresponds to a flow resistance of 0.14.

[0019] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0020] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0021] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A control method for different models of carbon load of GPF after-treatment of gasoline vehicle exhaust, characterized in that: The specific steps include: Step 1: Establishing a carbon load model, including a soot accumulation model and a soot regeneration model; Step 2: Carbon load model test and calibration, including bench calibration, vehicle verification and calibration; Step 3: Regeneration strategy, including passive regeneration and active regeneration.

2. The control method for different models of carbon load of GPF for exhaust aftertreatment of gasoline vehicles according to claim 1 is characterized by: The method for establishing the soot accumulation model is as follows: inputting parameters of engine speed and load to obtain a basic spectrum of the soot accumulation model; The air-fuel ratio is used to make air-fuel ratio corrections to the basic map, and the engine starting water temperature and running time are used for starting corrections; Load change rate, used for transient condition correction; The current engine water temperature is used for water temperature correction.

3. The control method for different models of carbon load of GPF for exhaust aftertreatment of gasoline vehicles according to claim 1 is characterized by: The method for establishing the soot regeneration model is as follows: inputting parameters of the current GPF carbon load, the GPF internal temperature and the exhaust oxygen flow, distinguishing between active regeneration and passive regeneration conditions, and establishing an open-loop regeneration model.

4. The control method for different models of carbon load of GPF for exhaust aftertreatment of gasoline vehicles according to claim 1 is characterized by: In the step 1, the real-time values ​​of the carbon accumulation model and the regeneration model are subtracted and input into the accumulation calculator, so as to obtain the model carbon load accumulated by the GPF at the current moment.

5. The control method for different models of carbon load of GPF for exhaust aftertreatment of gasoline vehicles according to claim 1 is characterized by: In the step three, the regeneration process is carried out under oxygen-rich and high temperature (>600° C.) conditions.

6. The control method for different models of carbon load of GPF for exhaust aftertreatment of gasoline vehicles according to claim 1 is characterized by: During the active regeneration: when the GPF temperature is less than 600°C and the GPF carbon load is greater than the set limit of 50%, the engine control system will trigger an active regeneration request, delay the ignition angle to increase the exhaust temperature to further heat the GPF; when the GPF temperature is between 600°C and 650°C and the GPF carbon load is greater than the set limit (50%), the engine control system will trigger an active regeneration request, delay the ignition angle to increase the exhaust temperature to heat the GPF, and use a lean air-fuel ratio to form a high-temperature and oxygen-rich environment inside the GPF; when the GPF temperature is greater than 750°C, the engine needs to enter the component protection mode and the active regeneration exits; when the GPF carbon load is greater than 150%, in order to prevent the GPF itself from being damaged during the regeneration process, the GPF regeneration process is usually prohibited, and the GPF needs to be processed or replaced at the after-sales service.

7. The control method for different models of carbon load of GPF for exhaust aftertreatment of gasoline vehicles according to claim 1 is characterized by: The passive regeneration process is as follows: when the accelerator pedal is suddenly released to slow down the car while driving at high speed, the engine throttle will quickly close from a larger opening position to an idle position, and the amount of fresh air entering the cylinder will be reduced. In order to avoid incomplete combustion caused by an over-rich mixer and to improve fuel economy and emissions, the engine is usually interrupted from injecting fuel. At this time, the engine will rotate at high speed under the action of the vehicle's inertia force, and the vehicle has no power request until the engine speed drops to the set speed or the throttle is reopened (the driver steps on the accelerator pedal again), and the fuel supply is resumed, that is, the deceleration and fuel cut-off process. During the deceleration and fuel cut-off process, the oxygen flow in the exhaust gas increases significantly. If the GPF temperature reaches the regeneration requirements at this time, the particulate matter in the GPF can be quickly burned off.

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