Pressurization control method for improving scavenging control

Abstract

The invention discloses a supercharging control method for improving scavenging control. The supercharging control method comprises the steps that whether the minimum supercharging closed-loop enabling pressure condition is met or not is determined according to the scavenging working condition state of an engine; when the minimum pressure condition of pressurization closed loop enabling is met, whether the pressurization closed loop is enabled or not is determined; and after the pressurization closed loop is enabled, pressurization closed loop control is carried out. According to the method, the minimum pressurization closed-loop enabling pressure condition is determined through the engine scavenging working condition, pressurization closed-loop control is conducted on the pressurization closed-loop enabling condition, when the scavenging working condition is activated, the pressurization closed-loop enabling condition is optimized in cooperation with scavenging work, and therefore the scavenging working performance is further assisted to be achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of engine control, and in particular relates to a boost control method for improving scavenging control. Background Art

[0002] In order to respond to the engine intake boost and engine torque increase requests, the boost system is controlled to achieve more exhaust energy to achieve boost. Boost control determines the engine's power and economy, etc. Boost closed-loop control refers to actively controlling the action of the boost actuator to achieve the tracking of the actual boost pressure and the target boost pressure. When the boost is not in closed-loop control, the opening of the boost actuator is not actively controlled. When there is no intake boost demand, the boost closed-loop control will be exited. In the prior art, the boost control performance of supercharged models when there is a scavenging demand is not perfect. Summary of the invention

[0003] The object of the present invention is to provide a boost control method for improving scavenging control, and when the scavenging condition is activated, the boost closed-loop enabling conditions are optimized in cooperation with the scavenging work, thereby further assisting in achieving the scavenging working performance.

[0004] In order to solve the above technical problems, the technical solution of the present invention is: a boost control method for improving scavenging control, comprising:

[0005] Determine whether the minimum pressure condition for boost closed loop enabling is met according to the engine scavenging working condition;

[0006] When the minimum pressure condition for boost closed loop enabling is met, determine whether the boost closed loop is enabled;

[0007] After the boost closed loop is enabled, boost closed loop control is performed.

[0008] The method for determining whether the minimum pressure condition for boost closed loop enabling is met is:

[0009] 1) When the difference between the target compressor outlet pressure and the minimum boost pressure is greater than the preset value A, the minimum pressure condition for enabling the boost closed loop is met;

[0010] 2) When the difference between the target compressor outlet pressure and the minimum boost pressure is greater than a preset value B; and the difference between the target boost pressure and the actual boost pressure is less than or equal to a preset value C; and the boost closed loop enabling time condition is not met; then the minimum pressure condition for boost closed loop enabling is not met; wherein, numerically, C>A>B;

[0011] 3) In other cases, the minimum pressure condition for enabling the boost closed loop maintains the state of the previous cycle; among them, the default state is when the vehicle is powered on, and the default state is that the minimum pressure condition for enabling the boost closed loop is not met.

[0012] The basis for determining whether the boost closed loop is enabled is:

[0013] 1) The minimum pressure condition for boost closed loop is met;

[0014] 2) The engine speed is greater than the preset engine speed value;

[0015] 3) The electronic pressure relief valve of the supercharger assembly is not opened;

[0016] Only when all the above conditions are met can it be determined that the boost closed loop is enabled, otherwise it is determined that the boost closed loop is not enabled.

[0017] The method for judging whether the boost closed loop enabling time condition is met is:

[0018] determining a scavenging request condition of a turbocharged direct injection engine;

[0019] Determine the scavenging allowable operating condition of the supercharged direct injection engine, judge whether the supercharged direct injection engine satisfies the following conditions: whether the speed is within a preset speed, whether the water temperature is within a first preset temperature, whether the intake air temperature is within a second preset temperature, whether the oil octane number is within a preset octane number, whether the number of pre-ignitions is within a preset number of pre-ignitions, and whether the catalytic temperature is within a third preset temperature; if so, determine that the supercharged direct injection engine satisfies the scavenging allowable operating condition; if not, determine that the supercharged direct injection engine does not satisfy the scavenging allowable operating condition;

[0020] If the supercharged direct injection engine satisfies both the scavenging request condition and the scavenging permission condition, the supercharged direct injection engine is immediately activated to enter the scavenging activation condition. If the supercharged direct injection engine only satisfies one of the scavenging request condition and the scavenging permission condition, it is further determined whether the corresponding process control of the supercharged direct injection engine is all under the control of the scavenging activation condition. If so, the supercharged direct injection engine is activated for at least the first preset time T1 and then exits the scavenging activation condition. If not, the supercharged direct injection engine is immediately exited from the scavenging request condition. When the engine enters the scavenging activation condition, it is determined that the boost closed-loop enabling condition is satisfied.

[0021] Determine the scavenging request condition of the turbocharged direct injection engine, including:

[0022] Determine whether the turbocharger's boost capacity meets the standard;

[0023] Determine whether the high torque request flag of the throttle is activated;

[0024] If the turbocharger's boost capability does not meet the standard and the throttle's high torque request flag is activated, it is determined that the turbocharged direct injection engine meets the scavenging request operating condition; if the turbocharger's boost capability meets the standard and / or the throttle's high torque request flag is not activated, it is determined that the turbocharged direct injection engine does not meet the scavenging request operating condition;

[0025] Determine whether the high torque request flag of the throttle is activated, including:

[0026] Determining the size of the throttle opening percentage and the first preset opening percentage and the second preset opening percentage;

[0027] If the throttle opening percentage is greater than or equal to a first preset opening percentage, it is determined that the throttle high torque request flag is activated; if the throttle opening percentage is less than a second preset opening percentage, it is determined that the throttle high torque request flag is not activated; if the throttle opening percentage is less than the first preset opening percentage and greater than or equal to the second preset opening percentage, it is determined that the activation state of the throttle high torque request flag remains unchanged;

[0028] Determine whether the turbocharger's boost capacity meets the standard, including:

[0029] Calculate the target boost pressure ratio rDesirdRatio and the actual boost pressure ratio rActRatio of the supercharged direct injection engine respectively;

[0030] Determine whether rDesirdRatio exceeds the scavenging activation pressure ratio limit rDesirdRatiolimit. If so, activate the scavenging flag corresponding to rDesirdRatio. If not, deactivate it.

[0031] Determine whether the difference between rDesirdRatio and rActRatio exceeds the pressure ratio limit rActRatiolimit. If so, activate the scavenging flag corresponding to rActRatio. If not, deactivate it.

[0032] If at least one of the scavenging flags corresponding to rDesirdRatio and rActRatio is activated, it is determined that the boost capacity of the turbine does not meet the standard;

[0033] Calculate the target boost pressure ratio rDesirdRatio and the actual boost pressure ratio rActRatio, specifically including:

[0034] The target intake pressure, actual intake pressure and actual gas pressure at the intake end of the compressor of the supercharged direct injection engine are recorded respectively, and the target boost pressure ratio rDesirdRatio is calculated according to the target intake pressure and the actual gas pressure at the intake end of the compressor, and the actual boost pressure ratio rActRatio is calculated according to the actual intake pressure and the actual gas pressure at the intake end of the compressor.

[0035] After the duration of the engine scavenging activation operating condition from a satisfied state to an unsatisfied state is greater than the second preset time T2, and the throttle target opening is lower than K1 times its maximum opening for the first time after the duration from the satisfied state to the unsatisfied state exceeds the second preset time T2, it is determined that the boost closed-loop enabling time condition is not met; wherein the preset coefficient K1 is related to the engine speed and the ratio of the actual throttle outlet pressure to the actual inlet pressure.

[0036] When the duration of the engine scavenging activation working condition from the satisfied state to the unsatisfied state is less than the second preset time T2, the difference between the second preset time T2 and the duration is set as the remaining time T0, and the remaining time T0 is optimized to obtain the optimized time T0'. The optimization method is expressed as:

[0037] T0′=max{T0×[1-f(Cnt LowKnock )-f(Cnt MediumKnock )-f(Cnt HighKnock )]×(1+r T1 ), 0}

[0038] That is, if the engine knocks during the process of satisfying the boost closed loop enabling time condition, the accumulated times Cnt corresponding to different knock intensities and different knock intensities are calculated respectively. LowKnock , Cnt MediumKnock , Cnt HighKnock Correction; the knock intensity includes at least low-intensity knock, medium-intensity knock and high-intensity knock, that is, Cnt LowKnock The accumulated number and Cnt for low intensity knock MediumKnock The accumulated number and Cnt for medium intensity knock HighKnock The cumulative number of high-intensity knocks; the time correction coefficient f (Cnt LowKnock ), time correction coefficient f(Cnt MediumKnock ), time correction coefficient f(Cnt HighKnock ) is determined based on reducing the risk of knocking and avoiding damage to the engine; T0 It is the self-learning coefficient of the remaining time T0, with a default value of 0, and can be saved after the vehicle is powered off.

[0039] Self-learning coefficient r for the remaining time T0 T0 The update conditions are:

[0040] ① If T0-T0′ is greater than the first preset time difference D1, and the first consecutive occurrence number CNT1 exceeds the preset number, then the T0 learning value r T0 The self-learning state is the first downward learning state, that is, r T0 Need to be reduced, expressed as rT0 =r T0 (z)-0.02, where r T0 (z) is the learning value of the last learning and storage time T0, and CNT1 is cleared at the same time. The newly learned and stored learning value is used when entering this situation judgment next time;

[0041] ② If T0-T0′ is less than or equal to the second preset time difference D2, and the second consecutive occurrence number CNT2 exceeds the preset number, the time T0 self-learning state is changed to the first upward learning state, that is, r T0 Need to be increased, expressed as r T0 =r T0 (z) + 0.01, the newly learned and stored learning value is used the next time the situation is judged;

[0042] ③In other cases, r T0 remain unchanged;

[0043] The priorities of the above update conditions ①-③ decrease step by step, that is, the priority of update condition ① is the highest, and the priority of update condition ③ is the lowest.

[0044] The initial value of the second preset time T2 and the calibration condition of the preset coefficient K1 are: within the third preset time T3 after the activation and exit of the boost closed loop enable, the throttle inlet intake pressure is stable, and then the calibration is performed; the judgment basis for the stability of the throttle inlet intake pressure is:

[0045]

[0046] Among them, p pre is the intake pressure at the throttle inlet, p pre (N) is the throttle inlet intake pressure at the Nth sampling cycle, p preFilter is the throttle inlet pressure after first-order low-pass filtering, p preFilte ( r N) is the filtered throttle inlet pressure in the Nth sampling period, p preFilte ( r N-1) is the filtered throttle inlet pressure of the N-1th sampling period, N = 1, 2, 3..., p preFilter (0) is equal to the throttle inlet pressure p at the 0th sampling cycle pre (0); Δt is the sampling period interval; KMan is the coefficient, expressed as: Where m is the number of engine cylinders, n is the engine speed, k pre is the throttle inlet pressure filter coefficient;

[0047] In|p pre (N)-p preFilter(N)|<min[p pre (N), p preFilter (N)]×r preLim When the conditions are met, it means that the throttle inlet pressure is in a relatively stable state.

[0048] A computer device is also provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the above methods when executing the computer program.

[0049] A computer-readable storage medium is also provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of any of the above methods are implemented.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The present invention determines the minimum pressure condition for boost closed-loop enabling and the boost closed-loop enabling condition through the engine scavenging working state, and performs boost closed-loop control. When the scavenging working state is activated, the boost closed-loop enabling condition is optimized in cooperation with the scavenging work, thereby further assisting in achieving the scavenging working performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of a flow chart of an embodiment of the present invention;

[0053] Figure 2 A schematic diagram of the architecture of a low-pressure EGR system in an embodiment of the present invention;

[0054] In the figure, 1-air filter, 2-mixing valve, 3-compressor, 4-throttle, 5-engine, 6-turbine, 7-catalyst, 8-particulate matter collector, 9-EGR cooler, 10-EGR valve, 11-temperature sensor, 12-differential pressure sensor. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0056] A boost control method for improving scavenging control is applied to a system with a low-pressure EGR system and an exhaust gas turbocharger system. The system structure includes an air filter 1, a mixing valve 2, a compressor 3, a throttle 4, an engine 5, a turbine 6, a catalyst 7, a particulate matter collector 8, an EGR cooler 9, an EGR valve 10, a temperature sensor 11, and a pressure difference sensor 12.

[0057] The supercharger compressor compresses fresh air for supercharging; the supercharger turbine controls the working efficiency of the turbine 6 by controlling the opening of the supercharger's exhaust bypass valve, thereby achieving different supercharging capabilities; compared with the non-low-pressure EGR system, the low-pressure EGR system has the following additional components: EGR cooler 9, EGR temperature sensor, EGR valve 10, EGR pressure difference sensor, mixing valve 2; the mixing valve 2 is used to adjust the pressure at the outlet of the EGR valve 10, increase the pressure difference at both ends of the EGR valve 10, and increase the EGR rate; the EGR cooler 9 is used to cool the exhaust gas to increase the exhaust gas flow rate and reduce the exhaust gas temperature; the EGR valve 10 has a throttling effect to control the exhaust gas flow entering the cylinder; the EGR temperature sensor is used to detect the exhaust gas temperature entering the EGR valve 10; the EGR pressure difference sensor is used to detect the pressure at the EGR inlet and outlet. The architecture of the low-pressure EGR system is as follows: Figure 2 shown.

[0058] The technical solution of the present invention is:

[0059] Embodiment 1:

[0060] A boost control method for improving scavenging control, such as Figure 1 As shown, including:

[0061] S1. Determine whether the minimum pressure condition for boost closed loop enabling is met according to the engine scavenging working condition;

[0062] S2. When the minimum pressure condition for enabling the boost closed loop is met, determining whether the boost closed loop is enabled;

[0063] S3. Perform boost closed-loop control after the boost closed-loop is enabled.

[0064] The method for determining whether the minimum pressure condition for boost closed loop enabling is met is:

[0065] 1) When the difference between the target compressor outlet pressure and the minimum boost pressure is greater than the preset value A, A=C1, C1 in this embodiment is 2kPa. Then the minimum pressure condition for enabling the boost closed loop is met;

[0066] 2) When the difference between the target compressor outlet pressure and the minimum boost pressure is greater than a preset value B, B=C2, C2 in this embodiment is -1 kPa; and the difference between the target boost pressure and the actual boost pressure is less than or equal to a preset value C, C in this embodiment is 3.5 kPa; and the boost closed loop enabling time condition is not met; then the minimum pressure condition for boost closed loop enabling is not met; wherein, numerically, C>A>B;

[0067] 3) In other cases, the minimum pressure condition for enabling the boost closed loop maintains the state of the previous cycle; among them, the default state is when the vehicle is powered on, and the default state is that the minimum pressure condition for enabling the boost closed loop is not met.

[0068] The basis for determining whether the boost closed loop is enabled is:

[0069] 1) The minimum pressure condition for boost closed loop is met;

[0070] 2) The engine speed is greater than a preset engine speed value, which is 600 rpm in this embodiment;

[0071] 3) The electronic pressure relief valve of the supercharger assembly is not opened;

[0072] Only when all the above conditions are met can it be determined that the boost closed loop is enabled, otherwise it is determined that the boost closed loop is not enabled.

[0073] The method for judging whether the boost closed loop enabling time condition is met is:

[0074] determining a scavenging request condition of a turbocharged direct injection engine;

[0075] Determine the scavenging allowable operating condition of the supercharged direct injection engine, judge whether the supercharged direct injection engine satisfies the following conditions: whether the speed is within a preset speed, whether the water temperature is within a first preset temperature, whether the intake air temperature is within a second preset temperature, whether the oil octane number is within a preset octane number, whether the number of pre-ignitions is within a preset number of pre-ignitions, and whether the catalytic temperature is within a third preset temperature; if so, determine that the supercharged direct injection engine satisfies the scavenging allowable operating condition; if not, determine that the supercharged direct injection engine does not satisfy the scavenging allowable operating condition;

[0076] If the supercharged direct injection engine satisfies both the scavenging request condition and the scavenging permission condition, the supercharged direct injection engine is immediately activated to enter the scavenging activation condition. If the supercharged direct injection engine only satisfies one of the scavenging request condition and the scavenging permission condition, it is further determined whether the corresponding process control of the supercharged direct injection engine is all under the control of the scavenging activation condition. If so, the supercharged direct injection engine is activated for at least the first preset time T1 and then exits the scavenging activation condition. If not, the supercharged direct injection engine is immediately exited from the scavenging request condition. When the engine enters the scavenging activation condition, it is determined that the boost closed-loop enabling condition is satisfied.

[0077] Determine the scavenging request condition of the turbocharged direct injection engine, including:

[0078] Determine whether the turbocharger's boost capacity meets the standard;

[0079] Determine whether the high torque request flag of the throttle is activated;

[0080] If the turbocharger's boost capability does not meet the standard and the throttle's high torque request flag is activated, it is determined that the turbocharged direct injection engine meets the scavenging request operating condition; if the turbocharger's boost capability meets the standard and / or the throttle's high torque request flag is not activated, it is determined that the turbocharged direct injection engine does not meet the scavenging request operating condition;

[0081] Determine whether the high torque request flag of the throttle is activated, including:

[0082] Determining the size of the throttle opening percentage and the first preset opening percentage and the second preset opening percentage;

[0083] If the throttle opening percentage is greater than or equal to a first preset opening percentage, it is determined that the throttle high torque request flag is activated; if the throttle opening percentage is less than a second preset opening percentage, it is determined that the throttle high torque request flag is not activated; if the throttle opening percentage is less than the first preset opening percentage and greater than or equal to the second preset opening percentage, it is determined that the activation state of the throttle high torque request flag remains unchanged;

[0084] Determine whether the turbocharger's boost capacity meets the standard, including:

[0085] Calculate the target boost pressure ratio rDesirdRatio and the actual boost pressure ratio rActRatio of the supercharged direct injection engine respectively;

[0086] Determine whether rDesirdRatio exceeds the scavenging activation pressure ratio limit rDesirdRatiolimit. If so, activate the scavenging flag corresponding to rDesirdRatio. If not, deactivate it.

[0087] Determine whether the difference between rDesirdRatio and rActRatio exceeds the pressure ratio limit rActRatiolimit. If so, activate the scavenging flag corresponding to rActRatio. If not, deactivate it.

[0088] If at least one of the scavenging flags corresponding to rDesirdRatio and rActRatio is activated, it is determined that the boost capacity of the turbine does not meet the standard;

[0089] Calculate the target boost pressure ratio rDesirdRatio and the actual boost pressure ratio rActRatio, specifically including:

[0090] The target intake pressure, actual intake pressure and actual gas pressure at the intake end of the compressor of the supercharged direct injection engine are recorded respectively, and the target boost pressure ratio rDesirdRatio is calculated according to the target intake pressure and the actual gas pressure at the intake end of the compressor, and the actual boost pressure ratio rActRatio is calculated according to the actual intake pressure and the actual gas pressure at the intake end of the compressor.

[0091] After the duration of the engine scavenging activation working condition from the satisfied state to the unsatisfied state is greater than the second preset time T2, and the throttle target opening is lower than K1 times its maximum opening for the first time after the duration from the satisfied state to the unsatisfied state exceeds the second preset time T2, it is determined that the boost closed-loop enabling time condition is not met; wherein, the preset coefficient K1 is related to the engine speed and the ratio of the actual throttle outlet pressure to the actual inlet pressure (referred to as the throttle pressure ratio) (in this embodiment, its value is shown in Table 1). At a certain engine speed, the smaller the throttle pressure ratio, the better the throttle can adjust the intake pressure. Therefore, the smaller the throttle pressure ratio, the smaller the preset coefficient K1, so as to quickly respond to the increase in torque.

[0092] Table 1

[0093]

[0094] When the duration of the engine scavenging activation working condition from the satisfied state to the unsatisfied state is less than the second preset time T2, the difference between the second preset time T2 and the duration is set as the remaining time T0, T0 must be less than or equal to T2, and the remaining time T0 is optimized to obtain the optimized time T0'. The optimization method is expressed as:

[0095] T0′=max{T0×[1-f(Cnt LowKnock )-f(Cnt MediumKnock )-f(Cnt HighKnock )]×(1+r T1 ), 0}

[0096] That is, if the engine knocks during the process of satisfying the boost closed loop enabling time condition, the accumulated times Cnt corresponding to different knock intensities and different knock intensities are calculated respectively. LowKnock , Cnt MediumKnock , Cnt HighKnock Correction; the knock intensity includes at least low-intensity knock, medium-intensity knock and high-intensity knock, that is, Cnt LowKnock The accumulated number and Cnt for low intensity knock MediumKnock The accumulated number and Cnt for medium intensity knock HighKnock The cumulative number of high-intensity knocks; the time correction coefficient f (Cnt LowKnock), time correction coefficient f(Cnt MediumKnock ), time correction coefficient f(Cnt HighKnock ) is determined based on reducing the risk of knocking and avoiding damage to the engine. Based on this, the specific calibration values ​​of this embodiment are shown in Table 2, Table 3 and Table 4:

[0097] Table 2

[0098] <![CDATA[Cnt LowKnock ]]> 0 3 5 7 12 15 <![CDATA[f(Cnt LowKnock )]]> 0 0 0.01 0.02 0.04 0.05

[0099] Table 3

[0100] <![CDATA[Cnt MediumKnock ]]> 0 3 5 7 12 15 <![CDATA[f(Cnt MediumKnock )]]> 0 0.02 0.05 0.06 0.08 0.1

[0101] Table 4

[0102] <![CDATA[Cnt HighKnock ]]> 0 1 3 7 10 12 <![CDATA[f(Cnt HighKnock )]]> 0 0.02 0.05 0.08 0.1 0.12

[0103] r T0 It is the self-learning coefficient of the remaining time T0, with a default value of 0, and can be saved after the vehicle is powered off.

[0104] Self-learning coefficient r for the remaining time T0 T0 The update conditions are:

[0105] ① If T0-T0′ is greater than the first preset time difference D1 (0.08s in this embodiment, indicating that the time adjustment caused by knock or pre-ignition is too large), and the first consecutive occurrence number CNT1 initial value is 0, which can be saved after the vehicle is powered off) exceeds the preset number (5 in this embodiment), then the T0 learning value r T0 The self-learning state is the first downward learning state, that is, r T0 Need to be reduced, expressed as r T0 =r T0 (z)-0.02, where r T0 (z) is the learning value of the last learning and storage time T0, and CNT1 is cleared at the same time. The newly learned and stored learning value is used when entering this situation judgment next time;

[0106] ② If T0-T0′ is less than or equal to the second preset time difference D2 (0.03s in this embodiment, indicating that knock or pre-ignition is not likely to occur), and the second consecutive occurrence number CNT2 (initial value is 0, which can be saved after the vehicle is powered off) exceeds the preset number, the time T0 self-learning state is changed to the first upward learning state, that is, r T0 Need to be increased, expressed as r T0 =r T0 (z) + 0.01, the newly learned and stored learning value is used the next time the situation is judged;

[0107] ③In other cases, rT0 remain unchanged;

[0108] The priorities of the above update conditions ①-③ decrease step by step, that is, the priority of update condition ① is the highest, and the priority of update condition ③ is the lowest.

[0109] The initial value of the second preset time T2 and the calibration condition of the preset coefficient K1 are: within the third preset time T3 (0.5s in this embodiment) after the activation and exit of the boost closed-loop enable, the throttle inlet intake pressure is stable, and then the calibration is performed; the judgment basis for the stability of the throttle inlet intake pressure is:

[0110]

[0111] Among them, p pre is the intake pressure at the throttle inlet, p pre (N) is the throttle inlet intake pressure at the Nth sampling cycle, p preFilter is the throttle inlet pressure after first-order low-pass filtering, p preFilte ( r N) is the filtered throttle inlet pressure in the Nth sampling period, p preFilter (N-1) is the filtered throttle inlet pressure of the N-1th sampling period, N = 1, 2, 3..., p preFilter (0) is equal to the throttle inlet pressure p at the 0th sampling cycle pre (0); Δt is the sampling period interval, which is 10ms in this embodiment; KMan is the coefficient, expressed as: (The number of engine cylinders in this embodiment is 4, k pre The calibrated speed is 1000rpm. The purpose of this setting is to normalize the process. Under different cylinder numbers and speeds, no special calibration is required. Only the 4-cylinder engine and the speed of 1000rpm k pre , thereby reducing the calibration test work), where m is the number of engine cylinders, n is the engine speed, k pre is the throttle inlet pressure filter coefficient, which is 0.1 in this embodiment.

[0112] In|p pre (N)-p preFilter (N)|<min[p pre (N), p preFilter (N)]×r preLim When the condition is met, it means that the throttle inlet pressure is in a relatively stable state (the throttle inlet pressure fluctuation is small). preLim In this embodiment, 0.1 is used.

[0113] When the vehicle is initially powered on, the boost closed-loop enabling time condition is not met.

[0114] Embodiment 2:

[0115] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the above methods when executing the computer program.

[0116] Embodiment 3:

[0117] A computer-readable storage medium stores a computer program, wherein the computer program, when executed by a processor, implements the steps of any of the methods described above.

[0118] It will be easily understood by those skilled in the art that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A boost control method for improving scavenging control, characterized in that: include: Determine whether the minimum pressure condition for boost closed loop enabling is met according to the engine scavenging working condition; When the minimum pressure condition for boost closed loop enabling is met, determine whether the boost closed loop is enabled; After the boost closed loop is enabled, boost closed loop control is performed.

2. A boost control method for improving scavenging control according to claim 1, characterized in that: The method for determining whether the minimum pressure condition for boost closed loop enable is met is: 1) When the difference between the target compressor outlet pressure and the minimum boost pressure is greater than the preset value A, the minimum pressure condition for enabling the boost closed loop is met; 2) When the difference between the target compressor outlet pressure and the minimum boost pressure is greater than a preset value B; and the difference between the target boost pressure and the actual boost pressure is less than or equal to a preset value C; and the boost closed loop enabling time condition is not met; then the minimum pressure condition for boost closed loop enabling is not met; wherein, numerically, C>A>B; 3) In other cases, the minimum pressure condition for enabling the boost closed loop maintains the state of the previous cycle; among them, the default state is when the vehicle is powered on, and the default state is that the minimum pressure condition for enabling the boost closed loop is not met.

3. The boost control method for improving scavenging control according to claim 1, characterized in that: The basis for determining whether the boost closed loop is enabled is: 1) The minimum pressure condition for boost closed loop is met; 2) The engine speed is greater than the preset engine speed value; 3) The electronic pressure relief valve of the supercharger assembly is not opened; Only when all the above conditions are met can it be determined that the boost closed loop is enabled, otherwise it is determined that the boost closed loop is not enabled.

4. A boost control method for improving scavenging control according to claim 2, characterized in that: The method for judging whether the boost closed loop enabling time condition is met is: determining a scavenging request condition of a turbocharged direct injection engine; Determine the scavenging allowable operating condition of the supercharged direct injection engine, judge whether the supercharged direct injection engine satisfies the following conditions: whether the speed is within a preset speed, whether the water temperature is within a first preset temperature, whether the intake air temperature is within a second preset temperature, whether the oil octane number is within a preset octane number, whether the number of pre-ignitions is within a preset number of pre-ignitions, and whether the catalytic temperature is within a third preset temperature; if so, determine that the supercharged direct injection engine satisfies the scavenging allowable operating condition; if not, determine that the supercharged direct injection engine does not satisfy the scavenging allowable operating condition; If the supercharged direct injection engine satisfies both the scavenging request operating condition and the scavenging permission operating condition, the supercharged direct injection engine is immediately activated to enter the scavenging activation operating condition; if the supercharged direct injection engine only satisfies one of the scavenging request operating condition or the scavenging permission operating condition, it is further determined whether the corresponding process control of the supercharged direct injection engine is all under the control of the scavenging activation operating condition; if so, the supercharged direct injection engine is activated for at least the first preset time T1 before exiting the scavenging activation operating condition; if not, the supercharged direct injection engine is immediately exited from the scavenging request operating condition; When the engine enters the scavenging activation condition, it is determined that the boost closed loop enabling condition is met; Determine the scavenging request condition of the turbocharged direct injection engine, including: Determine whether the turbocharger's boost capacity meets the standard; Determine whether the high torque request flag of the throttle is activated; If the turbocharger's boost capability does not meet the standard and the throttle's high torque request flag is activated, it is determined that the turbocharged direct injection engine meets the scavenging request operating condition; if the turbocharger's boost capability meets the standard and / or the throttle's high torque request flag is not activated, it is determined that the turbocharged direct injection engine does not meet the scavenging request operating condition; Determine whether the high torque request flag of the throttle is activated, including: Determining the size of the throttle opening percentage and the first preset opening percentage and the second preset opening percentage; If the throttle opening percentage is greater than or equal to a first preset opening percentage, it is determined that the throttle high torque request flag is activated; if the throttle opening percentage is less than a second preset opening percentage, it is determined that the throttle high torque request flag is not activated; if the throttle opening percentage is less than the first preset opening percentage and greater than or equal to the second preset opening percentage, it is determined that the activation state of the throttle high torque request flag remains unchanged; Determine whether the turbocharger's boost capacity meets the standard, including: Calculate the target boost pressure ratio rDesirdRatio and the actual boost pressure ratio rActRatio of the supercharged direct injection engine respectively; Determine whether rDesirdRatio exceeds the scavenging activation pressure ratio limit rDesirdRatiolimit. If so, activate the scavenging flag corresponding to rDesirdRatio. If not, deactivate it. Determine whether the difference between rDesirdRatio and rActRatio exceeds the pressure ratio limit rActRatiolimit. If so, activate the scavenging flag corresponding to rActRatio. If not, deactivate it. If at least one of the scavenging flags corresponding to rDesirdRatio and rActRatio is activated, it is determined that the boost capacity of the turbine does not meet the standard; Calculate the target boost pressure ratio rDesirdRatio and the actual boost pressure ratio rActRatio, specifically including: The target intake pressure, actual intake pressure and actual gas pressure at the intake end of the compressor of the supercharged direct injection engine are recorded respectively, and the target boost pressure ratio rDesirdRatio is calculated according to the target intake pressure and the actual gas pressure at the intake end of the compressor, and the actual boost pressure ratio rActRatio is calculated according to the actual intake pressure and the actual gas pressure at the intake end of the compressor.

5. A boost control method for improving scavenging control according to claim 4, characterized in that: After the duration of the engine scavenging activation operating condition from a satisfied state to an unsatisfied state is greater than the second preset time T2, and the throttle target opening is lower than K1 times its maximum opening for the first time after the duration from the satisfied state to the unsatisfied state exceeds the second preset time T2, it is determined that the boost closed-loop enabling time condition is not met; wherein the preset coefficient K1 is related to the engine speed and the ratio of the actual throttle outlet pressure to the actual inlet pressure.

6. A boost control method for improving scavenging control according to claim 5, characterized in that: When the duration of the engine scavenging activation working condition from the satisfied state to the unsatisfied state is less than the second preset time T2, the difference between the second preset time T2 and the duration is set as the remaining time T0, and the remaining time T0 is optimized to obtain the optimized time T0'. The optimization method is expressed as: T0′=max{T0×[1-f(Cnt LowKnock )-f(Cnt MediumKnock )-f(Cnt HighKnock )]×1+r T1 ),0} That is, if the engine knocks during the process of satisfying the boost closed loop enabling time condition, the accumulated times Cnt corresponding to different knock intensities and different knock intensities are calculated respectively. LowKnock , Cnt MediumKnock , Cnt HighKnock Correction; the knock intensity includes at least low-intensity knock, medium-intensity knock and high-intensity knock, that is, Cnt LowKnock The accumulated number and Cnt for low intensity knock MediumKnock The accumulated number and Cnt for medium intensity knock HighKnock The cumulative number of high-intensity knocks; the time correction coefficient f (Cnt LowKnock ), time correction coefficient f(Cnt MediumKnock ), time correction coefficient f(Cnt HighKnock ) is determined based on reducing the risk of knocking and avoiding damage to the engine; T0 It is the self-learning coefficient of the remaining time T0, with a default value of 0, and can be saved after the vehicle is powered off.

7. A boost control method for improving scavenging control according to claim 6, characterized in that: Self-learning coefficient r for the remaining time T0 T0 The update conditions are: ① If T0-T0′ is greater than the first preset time difference D1, and the first consecutive occurrence number CNT1 exceeds the preset number, then the T0 learning value r T0 The self-learning state is the first downward learning state, that is, r T0 Need to be reduced, expressed as r T0 =r T0 (z)-0.02, where r T0 (z) is the learning value of the last learning and storage time T0, and CNT1 is cleared at the same time. The newly learned and stored learning value is used when entering this situation judgment next time; ② If T0-T0′ is less than or equal to the second preset time difference D2, and the second consecutive occurrence number CNT2 exceeds the preset number, the time T0 self-learning state is changed to the first upward learning state, that is, r T0 Need to be increased, expressed as r T0 =r T0 (z) + 0.01, the newly learned and stored learning value is used the next time the situation is judged; ③In other cases, r T0 remain unchanged; The priorities of the above update conditions ①-③ decrease step by step, that is, the priority of update condition ① is the highest, and the priority of update condition ③ is the lowest.

8. The boost control method for improving scavenging control according to claim 5, characterized in that: The initial value of the second preset time T2 and the calibration condition of the preset coefficient K1 are: within the third preset time T3 after the activation and exit of the boost closed loop enable, the throttle inlet intake pressure is stable, and then the calibration is performed; the judgment basis for the stability of the throttle inlet intake pressure is: Among them, p pre is the intake pressure at the throttle inlet, p pre (N) is the throttle inlet intake pressure at the Nth sampling cycle, p preFilter is the throttle inlet pressure after first-order low-pass filtering, p preFilte ( r N) is the filtered throttle inlet pressure in the Nth sampling period, p preFilte ( r N-1) is the filtered throttle inlet pressure of the N-1th sampling period, N = 1, 2, 3..., p preFilter (0) is equal to the throttle inlet pressure p at the 0th sampling cycle pre (0); Δt is the sampling period interval; KMan is the coefficient, expressed as: Where m is the number of engine cylinders, n is the engine speed, k pre is the throttle inlet pressure filter coefficient; In | ppre (N)-p preFilter (N)| <min[ ppre (N), p preFilter (N]×r preLim When the conditions are met, it means that the throttle inlet pressure is in a relatively stable state.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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