EGR control method based on performance improvement, electronic equipment and vehicle

Abstract

The invention relates to the technical field of vehicle engine control, in particular to an EGR control method based on performance improvement, electronic equipment and a vehicle. According to the EGR control method based on performance improvement, the basic duration for keeping the target opening degree of the EGR valve unchanged after an EGR closed loop exits is determined, and the remaining duration for keeping the target opening degree of the EGR valve unchanged is optimized based on the variation of the oxygen storage capacity coefficient of the catalytic converter and the variation of the air-fuel ratio; and the final EGR valve target opening degree maintaining time after the EGR closed loop quits is obtained, so that optimization treatment is conducted on EGR valve target opening degree control after the EGR closed loop quits, and then the stability of engine emission and pressurization control in the EGR closed loop quitting process is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle engine control, and in particular to an EGR control method based on improving performance, an electronic device and a vehicle. Background Art

[0002] Exhaust gas recirculation (EGR) takes exhaust gas from the exhaust and enters the intake system. Studies have shown that the EGR system has certain advantages in improving emissions, reducing fuel consumption and improving anti-knock capabilities. The actual EGR rate entering the cylinder is an important basis for the engine to estimate the fresh air flow rate, and is also an important parameter for controlling the throttle opening. The higher the EGR rate accuracy, the more accurate the fresh air estimation, and the more reasonable the throttle opening control, so that the engine's demand for fresh air volume can be met, meeting the vehicle's power and emission requirements; at the same time, based on the actual EGR rate, the ignition timing will be optimized to improve power and economy. Summary of the invention

[0003] The technical problem to be solved by the present invention is: in view of the shortcomings of the prior art, an EGR control method based on improving performance is provided, which can improve the stability of engine emissions and boost control during the EGR closed-loop exit process by optimizing the control of the EGR valve target opening after the EGR closed-loop exit.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] An EGR control method based on improving performance includes the following control strategies:

[0006] S1, when it is read that the EGR closed-loop enabling condition changes from being satisfied to being unsatisfied, the pressure ratio coefficient is determined according to the ratio of the actual pressure at the mixing valve outlet to the actual pressure at the mixing valve inlet, and the ratio of the actual pressure at the throttle outlet to the actual pressure at the throttle inlet, and the initial value of the time length during which the EGR valve target opening is maintained unchanged is determined according to the pressure ratio coefficient and the current real-time engine speed;

[0007] S2, based on the change of the catalyst oxygen storage capacity coefficient, the change of the air-fuel ratio coefficient and the change of the mixing valve outlet pressure, and combined with the remaining time self-learning coefficient, the remaining time value for maintaining the target opening of the EGR valve is self-learned and updated for optimization;

[0008] S3, determining the final EGR valve target opening maintenance time after the EGR closed loop exits according to the initial time value and the updated optimized remaining time value.

[0009] Furthermore, the initial value of the time duration during which the EGR valve target opening remains unchanged is t=f(r PreRatio ,n), where n is the current real-time engine speed, r PreRatiois the pressure ratio coefficient; the pressure ratio coefficient in, is the actual pressure p at the outlet of the mixing valve AfMixAct The actual pressure p of the mixing valve inlet BfMixAct The ratio, is the pressure ratio correction factor, which is based on the actual throttle outlet pressure p AfThrAct The actual throttle inlet pressure p BfThrAct Ratio Query the calibration table to obtain it.

[0010] Furthermore, the calibration basis of the initial value t of the time duration during which the EGR valve target opening is maintained unchanged is: N from the first sampling period when the EGR closed-loop enabling condition is not met to the end of the initial value t of the time duration Boost In a sampling cycle, the difference between the throttle outlet target pressure and the throttle outlet actual pressure p AftThrErr Satisfy the following formula:

[0011] |p BoostFilter (N)-p BoostErr (N)<min[p BoostErr (N), p BoostErrFilter (N)]×r BoostErrLim

[0012] Among them, p BoostErrFilter (N) = K BoostErr ×[p BoostErr (N)-p BoostErrFilter (N-1)]+p BoostErrFilter (N-1)

[0013] In the formula, p BoostErr is the original value of the difference between the target boost pressure and the actual boost pressure, p BoostErr (N) is the pressure difference p of the Nth sampling period BoostErr Original value, p BoostErrFilter is the pressure difference after first-order low-pass filtering, p BoostErrFilter (N) is the pressure difference after filtering in the Nth sampling period, p BoostErrFilter (N-1) is the pressure difference after filtering in the N-1th sampling period, N = 1, 2, 3..., K BoostErr is the coefficient: k BoostErr is the pressure difference filter coefficient.

[0014] Furthermore, Among them, the optimized value of supercharger response time τ = τ Boost ×(1+r Boost ), r Boost is the supercharger response time τ BoostThe self-learning coefficient has a default value of 0 and can be saved after the vehicle is powered off; the supercharger response time τ Boost It is the time required for the mixture to flow from the supercharger compressor to the throttle valve outlet.

[0015] Furthermore, the remaining time value for maintaining the target opening of the EGR valve unchanged is optimized by self-learning update, specifically as follows:

[0016]

[0017] Wherein, the catalyst oxygen storage capacity coefficient r CatalystOxygen The change of Δr CatalystOxygen Take the nearest The oxygen storage capacity coefficient of the catalyst within the sampling period r CatalystOxygen Maximum value and catalyst oxygen storage capacity coefficient r CatalystOxygen Minimum difference, τ EGR is the time required for exhaust gas to flow from the EGR valve to the cylinder, r t1 It is the self-learning coefficient of the remaining time value t1, its default value is 0, and it can be saved after the vehicle is powered off.

[0018] In Δr CatalystOxygen Under the same conditions, if the pressure ratio r PreRatio The smaller the value, the smaller f(r PreRatio , Δr CatalystOxygen ) is smaller; in the pressure ratio r PreRatio Under the same circumstances, if Δr CatalystOxygen The larger the value, the greater f(r PreRatio , Δr CatalystOxygen ) is larger;

[0019] In Δr CatalystOxygen Under the same circumstances, if the pressure ratio The smaller the The smaller the pressure ratio Under the same circumstances, if Δr CatalystOxygen The larger the The bigger;

[0020] The boost pressure difference change Δp BoostErr Under the same conditions, if the mixing valve outlet pressure p AfMixAct Change Δp AfMixAct The smaller the value, the smaller f(Δp AfMixAct , Δp BoostErr ) is smaller; at the outlet pressure p of the mixing valve AfMixAct Change Δp AfMixAct Under the same conditions, if the boost pressure difference change Δp BoostErr The larger the value, the greater f(Δp AfMixAct , Δp BoostErr ) is larger.

[0021] Furthermore, the supercharger response time self-learning coefficient r Boost and the remaining time self-learning coefficient r t1 The self-learning update process is as follows:

[0022] 1) If t1'-t1 is greater than the preset value C1, and the number of consecutive occurrences CNT1 exceeds the preset value CNT0, then set r t1 Equal to the r stored in the last learning t1 The learning value plus the preset update value Z1, let r Boost Equal to the r stored in the last learning Boost The learning value is added to the preset update value Z2, and CNT1 is cleared at the same time;

[0023] 2) If t1'-t1 is not greater than the preset value -C2, and the number of consecutive occurrences CNT2 exceeds the preset value CNT0, then set r t1 Equal to the r stored in the last learning t1 The learning value minus the preset update value Z1, let r Boost Equal to the r stored in the last learning Boost The learning value is subtracted from the preset update value Z2, and CNT2 is cleared to zero;

[0024] 3) If t1'-t1 is greater than the preset value C1, and t1'-t1 is not greater than the preset value -C2 during the last learning, then let r t1 Equal to the r stored in the last learning t1 The learning value plus the preset update value Z1;

[0025] 4) If t1'-t1 is not greater than the preset value -C2, and t1'-t1 was greater than the preset value C1 during the last learning, then set r t1 Equal to the r stored in the last learning t1 The learning value minus the preset update value Z1;

[0026] 5) In other cases, r t1 and r Boost Remain unchanged.

[0027] Furthermore, if the following conditions are met, r is continued to be driven in the current driving cycle. t1 To update:

[0028] 1) If t1'-t1 is greater than the preset value C1, and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change of Δr CatalystOxygen Exceeds the preset value C3, catalyst oxygen storage capacity coefficient r CatalystOxygen exceeds the preset value C4, and the number of consecutive occurrences CNT3 exceeds the preset value CNT0, then r t1Equal to the r stored in the last learning t1 The learning value is added to the preset update value Z3, and CNT3 is cleared at the same time;

[0029] 2) If t1'-t1 is not greater than the preset value C2, and the catalyst oxygen storage capacity coefficient r CatalystO x ygen The change of Δr CatalystOxygen Exceeds the preset value C5, catalyst oxygen storage capacity coefficient r CatalystOxygen exceeds the preset value C6, and the number of consecutive occurrences CNT4 exceeds the preset value CNT0, then r t1 Equal to the r stored in the last learning t1 The learning value is subtracted from the preset update value Z4, and CNT4 is cleared to zero;

[0030] 3) In other cases, r t1 Remain unchanged.

[0031] Compared with the prior art, the present invention has the following main advantages:

[0032] The present invention proposes an EGR control method based on improving performance, by determining the basic time for which the target opening of the EGR valve remains unchanged after the EGR closed-loop exits, and optimizing the remaining time for which the target opening of the EGR valve remains unchanged based on the change in the catalyst oxygen storage coefficient and the change in the air-fuel ratio, the final EGR valve target opening maintenance time after the EGR closed-loop exits is obtained, so as to optimize the control of the target opening of the EGR valve after the EGR closed-loop exits, thereby improving the stability of engine emissions and boost control during the EGR closed-loop exit process. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is an overall flow chart of the EGR control method based on improving performance in the first embodiment of the present invention;

[0034] Figure 2 Schematic diagram of the EGR system in Embodiment 1 of the present invention;

[0035] Figure 3 Schematic diagram of the steps of the EGR control method in the second embodiment of the present invention.

[0036] 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. Pressure difference sensor. DETAILED DESCRIPTION

[0037] 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.

[0038] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0039] In the present invention, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically limited.

[0040] In the first embodiment, when the EGR system closed-loop enabling conditions are met, the traditional PID closed-loop control algorithm is used to control the mixing valve and the EGR valve to achieve the following of the EGR rate; when the EGR closed-loop enabling conditions are not met, how to set the EGR valve target opening is the main consideration of this application.

[0041] This embodiment provides an EGR control method based on improving performance, such as Figure 1 As shown, the main strategies include the following:

[0042] S1, when it is read that the EGR closed-loop enabling condition changes from being satisfied to being unsatisfied, the pressure ratio coefficient is determined according to the ratio of the actual pressure at the mixing valve outlet to the actual pressure at the mixing valve inlet, and the ratio of the actual pressure at the throttle outlet to the actual pressure at the throttle inlet, and the initial value of the time length during which the EGR valve target opening is maintained unchanged is determined according to the pressure ratio coefficient and the current real-time engine speed;

[0043] S2, based on the change of the catalyst oxygen storage capacity coefficient, the change of the air-fuel ratio coefficient and the change of the mixing valve outlet pressure, and combined with the remaining time self-learning coefficient, the remaining time value for maintaining the target opening of the EGR valve is self-learned and updated for optimization;

[0044] S3, determining the final EGR valve target opening maintenance time after the EGR closed loop exits according to the initial time value and the updated optimized remaining time value.

[0045] like Figure 2As shown, the EGR system mainly includes:

[0046] An air filter 1, wherein a mixing valve 2 is connected to the rear of the air filter 1;

[0047] 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 extend two air flow paths from the mixing valve 2;

[0048] A compressor 3 is installed on one of the air flow passages, and an EGR cooler 9 is installed on the other air flow passage;

[0049] The compressor 3 is connected to a throttle valve 4, and the throttle valve 4 is connected to an engine 5 for compressing fresh air for supercharging;

[0050] The engine 5 is connected to a turbine 6 to control the opening of the wastegate valve;

[0051] The turbine 6 is connected to a catalyst 7, and the catalyst 7 is connected to a particle collector 8;

[0052] The EGR cooler 9 is used to receive the exhaust gas output by the particulate matter collector 8 and cool it to increase the exhaust gas flow rate;

[0053] The EGR valve 10 is connected to the EGR cooler 9 at one end and the mixing valve 2 at the other end, and is used to control the exhaust gas flow entering the cylinder;

[0054] A temperature sensor 11 is installed between the EGR valve 10 and the EGR cooler 9 to detect the temperature of the exhaust gas entering the EGR valve 10;

[0055] A differential pressure sensor 12 is installed between the inlet and the outlet of the EGR valve 10 to detect the pressures at the inlet and the outlet of the EGR valve 10 .

[0056] Embodiment 2: This embodiment provides an EGR control method based on improving performance, such as Figure 3 As shown, it mainly includes:

[0057] Assuming that the EGR control demand is the largest, the EGR valve target opening pct EGRDsrd The opening is 100%; when the EGR control demand is minimum, the EGR valve target opening pct EGRDsrd The opening is 0%.

[0058] 1) Once the EGR closed loop enabling conditions are met, the EGR valve target opening pct EGRDsrd It is executed according to the closed-loop control requirements and is not within the scope of this patent.

[0059] 2) Once the EGR closed-loop enabling condition is read from satisfied to not satisfied (i.e., the previous sampling cycle detected that it was satisfied, and the current sampling cycle is not satisfied. The sampling cycle in this example is 10ms), then according to the actual pressure p AfMixAct (It can be replaced by EGR valve outlet pressure or other methods) and the actual mixing valve inlet pressure p BfMixAct Ratio Actual throttle outlet pressure p AfThrAct The actual throttle inlet pressure p BfThrAct Ratio Determine the pressure ratio coefficient together And the current engine real-time speed n determines the EGR valve target opening pct EGRDsrd The initial value t of the duration is maintained unchanged, and the purpose of maintaining the EGR valve is to stabilize the boost inlet pressure and avoid affecting the boost control responsiveness. That is, determine pct EGRDsrd =pct EGRDsrd (z) duration, where pct EGRDsrd (z) is the EGR valve target opening in the previous sampling cycle, that is, the EGR valve target opening when the EGR closed-loop condition is met in the last sampling cycle. The initial value of the duration t starts from the first sampling cycle when the EGR closed-loop condition is not met. is the pressure ratio correction factor, mainly considering When the value is larger, the throttle control ability is poor, and the pressure control accuracy of the supercharger is at risk. In order to avoid the problem of supercharger pressure control accuracy, improvements should be made. The query calibration table is as follows:

[0060]

[0061] Furthermore, t = f(r PreRatio ,n) is calibrated based on the N from the first sampling period when the EGR closed-loop condition is not met to the end of the initial value t of the duration. Boost Within a sampling period (N Boost Pick ), the difference between the throttle outlet target pressure and the throttle outlet actual pressure p AftThrErr The fluctuation of is within the preset range. τ=τ Boost ×(1+r Boost ) is the supercharger response time. Boost is the supercharger response time τ Boost The self-learning coefficient has a default value of 0 and can be saved after the vehicle is powered off.

[0062] Supercharger response time τ BoostIt is the time for the mixture to flow from the supercharger compressor to the throttle outlet. This part can be different for different engine speeds n eng and the actual intake air density rho of different cylinders Act Under this condition, the average value of multiple sampling data under different EGR rates is obtained, so τ Boost is the engine speed n eng and the actual intake air density rho entering the cylinder Act Determined (can also be obtained directly through bench calibration).

[0063] The judgment is based on the following: when the target boost pressure remains unchanged,

[0064] p BoostErrFilter (N) = K BoostErr ×[p BoostErr (N)-p BoostErrFilter (N-1)]+p BoostErrFilter (N-1)

[0065] Among them, p BoostErr is the original value of the difference between the target boost pressure and the actual boost pressure, p BoostErr (N) is the pressure difference p of the Nth sampling period BoostErr Original value, p BoostErrFilter is the pressure difference after first-order low-pass filtering, p BoostErrFilter (N) is the pressure difference after filtering in the Nth sampling period, p BoostErrFilter (N-1) is the pressure difference after filtering in the N-1th sampling period, N = 1, 2, 3..., p BoostErrFilter (0) is equal to the pressure difference p at the 0th sampling period AftThrErr (0), in particular, the 0th sampling period occurs at the moment when the EGR system closed loop is enabled; the sampling period interval Δt in this example is 10ms. BoostErr is the coefficient: k BoostErr is the pressure difference filter coefficient, which is 0.2 in this example.

[0066] In|p BoostFilter (N)-p BoostErr (N)|<min[p BoostErr (N), p BoostErrFilter (N)]×r BoostErrLim Condition, N from the first sampling period when the EGR closed loop condition is not met to the end of the initial value t of the duration Boost If the value is satisfied within the sampling period, it means the difference between the target boost pressure and the actual boost pressure is p BoostErr The fluctuation of is within the preset range, where r BoostErrLim In this example, the value is 0.1.

[0067] Based on the above calibration basis, it is determined that t = f (r PreRatio ,n), under the same speed n, if the pressure ratio r PreRatio The smaller the initial value t of the time is, the smaller the difference between the target boost pressure and the actual boost pressure p BoostErr The fluctuation of the pressure ratio is within the preset range; PreRatio Under the same conditions, if the speed n is smaller, the initial value t of the duration is larger to meet the difference p between the target boost pressure and the actual boost pressure. BoostErr The fluctuation of is within the preset range;

[0068] The above determines the EGR valve target opening pct EGRDsrd The initial value t of the time duration that remains unchanged is mainly obtained by calibration on the engine test bench.

[0069] However, during the actual vehicle calibration test, when the following situations occur, it is also necessary to optimize the remaining time for the EGR valve target opening to remain unchanged:

[0070] After the EGR closed loop enabling condition is exited, the EGR valve target opening pct EGRDsrd Under the condition of maintaining the same state (i.e. EGR is exited but the control is stable), based on the catalyst oxygen storage capacity coefficient r CatalystOxygen Change Δr CatalystOxygen , air-fuel ratio coefficient Change and mixing valve outlet pressure p AfMixAct Change Δp AfMixAct The original remaining time t1 is updated and optimized to obtain t1'. The remaining time t1 refers to the time from the current moment to the EGR valve target opening pct EGRDsrd The time when the EGR closed loop enabling condition is exited (t1 is not necessarily equal to t, because the change in boost pressure difference may occur after a period of time when the EGR closed loop enabling condition is exited). Medium ActFuelAir Ratio is the actual fuel-air ratio, r StadFuelAirRatio For the ideal fuel-air ratio, in this example it is taken as 1 / 14.3.

[0071] Wherein, the catalyst oxygen storage capacity coefficient r CatalystOxygen :According to the oxygen storage capacity of the catalyst divided by the maximum oxygen storage capacity, the current catalyst oxygen storage coefficient r can be obtained CatalystOxygen, the value range is between 0 and 1. The smaller the oxygen storage coefficient, the smaller the oxygen storage capacity of the catalyst. At this time, the EGR rate can be appropriately reduced to reduce the production of NOx. (Refer to the existing patent CN110259553A "A method, device and electronic device for calculating the oxygen storage capacity of a three-way catalytic converter" to read the oxygen storage capacity of the catalyst in real time; CN104594986A "A method for diagnosing engine catalyst degradation" to read the maximum oxygen storage capacity of the catalyst in real time;)

[0072] The mixing valve outlet pressure p AfMixAct Change Δp AfMixAct Take the nearest The mixing valve outlet pressure p before the sampling cycle (a single sampling cycle is 10ms) AfMixAct Maximum and mixing valve outlet pressure p AfMixAct The difference between the minimum values ​​(if the mixing valve outlet pressure p AfMixAct The maximum value occurs at a time when the mixing valve outlet pressure p AfMixAct The minimum value occurs later, so the mixing valve outlet pressure p AfMixAct Change Δp AfMixAct is a positive value; if the mixing valve outlet pressure p AfMixAct The maximum value occurs at a time when the mixing valve outlet pressure p AfMixAct The minimum value occurs earlier, the mixing valve outlet pressure p AfMixAct Change Δp AfMixAct is a negative value; if the mixing valve outlet pressure p AfMixAct The time when the maximum value occurs is related to the mixing valve outlet pressure p AfMixAct The minimum value occurs at the same time, then the mixing valve outlet pressure p AfMixAct Change Δp AfMixAct is 0).

[0073] The change in the outlet pressure of the mixing valve is considered because if the change is too large, it will deteriorate the trend of the boost pressure control stability, thereby affecting the subsequent boost pressure control stability.

[0074] The catalyst oxygen storage capacity coefficient r CatalystOxygen The change of Δr CatalystOxygen Take the nearest The catalyst oxygen storage capacity coefficient r within the sampling period (a single sampling period is 10ms) CatalystOxygen Maximum value and catalyst oxygen storage capacity coefficient r CatalystOxygen The difference between the minimum values ​​(if the catalyst oxygen storage capacity coefficient r CatalystOxygen The maximum value occurs at a time ratio of the catalyst oxygen storage capacity coefficient r CatalystOxygen The minimum value occurs later, so the oxygen storage capacity coefficient of the mixed catalyst is r CatalystOxygen Change Δr CatalystOxygenis a positive value; if the catalyst oxygen storage capacity coefficient r CatalystOxygen The maximum value occurs at a time ratio of the catalyst oxygen storage capacity coefficient r CatalystOxygen The minimum value occurs earlier, so the catalyst oxygen storage capacity coefficient r CatalystOxygen Change Δr CatalystOxygen is a negative value; if the catalyst oxygen storage capacity coefficient r CatalystOxygen The time when the maximum value occurs is related to the catalyst oxygen storage capacity coefficient r CatalystOxygen The minimum value occurs at the same time, so the catalyst oxygen storage capacity coefficient r CatalystOxygen Change Δr CatalystOxygen is 0).

[0075] Considering the catalyst oxygen storage capacity coefficient r CatalystOxygen The change amount and air-fuel ratio change amount are because if the change amount is too large, it will have a deteriorating effect on the trend of boost control stability, thereby affecting the subsequent boost pressure control stability.

[0076] τ EGR is the time for exhaust gas to flow from the EGR valve to the cylinder. This part can be different for different engine speeds n eng and the actual intake air density rho of different cylinders Act Under this condition, the average value of multiple sampling data under different EGR rates is obtained, so τ EGR is the engine speed n eng and the actual intake air density rho entering the cylinder Act Determined (can also be obtained through bench calibration).

[0077]

[0078] The calibration is based on the fact that the time delay is set after t1' ends. The difference between the target boost pressure and the actual boost pressure is ensured BoostErr The fluctuation of is within the preset range, and the catalyst oxygen storage capacity coefficient r CatalystOxygen does not exceed the preset value, which is 0.9 in this example, and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change does not exceed the preset value, which is 0.2 in this example.

[0079] In Δr CatalystOxygen Under the same conditions, if the pressure ratio r PreRatio The smaller the value, the smaller f(r PreRatio , Δr CatalystOxygen ) is smaller; in the pressure ratio r PreRatio Under the same circumstances, if Δr CatalystOxygen The larger the value, the greater f(r PreRatio , Δr CatalystOxygen ) is larger.

[0080] In ΔrCatalystOxygen Under the same circumstances, if the pressure ratio The smaller the The smaller the pressure ratio Under the same circumstances, if Δr CatalystOxygen The larger the The bigger.

[0081] The change in boost pressure difference Δp BoostErr Under the same conditions, if the mixing valve outlet pressure p AfMixAct Change Δp AfMixAct The smaller the value, the smaller f(Δp AfMixAct , Δp BoostErr ) is smaller; at the outlet pressure p of the mixing valve AfMixAct Change Δp AfMixAct Under the same conditions, if the boost pressure difference change Δp BoostErr The larger the value, the greater f(Δp AfMixAct , Δp BoostErr ) is larger.

[0082] The time limit of t1 is between the maximum value tmax (0.2s in this example) and the minimum value tmin (0s in this example) to avoid excessive adjustment and poor robustness of intake system control; t1 It is the self-learning coefficient of time t1, its default value is 0, and it can be saved after the vehicle is powered off.

[0083] Furthermore, the learning value r at time t1 t1 and supercharger response time τ Boost The self-learning coefficient r Boost The learning situation is as follows:

[0084] 1. If t1'-t1 is greater than the preset value C1 (0.1s in this example), it means that the adjustment is too large due to the excessive fluctuation of the boost pressure difference), and Δp AfMixAct If the value exceeds the preset value (±20 kPa in this example), and the number of consecutive occurrences CNT1 (initial value is 0, which can be saved after the vehicle is powered off) exceeds the preset value (5 in this example), it means that the influence of the boost pressure difference causes the time t1 to increase continuously. In order to avoid the influence of the boost pressure difference fluctuation due to the reduction, the self-learning state of time t1 is changed to the upward learning state 1, that is, r t1 Need to increase. t1 =r t1 (z)+0.02, r Boost =r Boost (z)+0.1, where r t1 (z) is the learning value stored at the last learning time t1, r Boost (z) is the r stored in the last learning BoostLearning value. CNT1 is cleared at the same time. The newly learned and stored learning value is used the next time the situation is judged. CNT1 is updated at most once during each driving cycle.

[0085] 2. If t1'-t1 is not greater than the preset value -C2 (0.1s in this example), it means that the adjustment is too large due to excessive fluctuation of the boost pressure difference), and Δp AfMixAct If the time t1 is reduced due to the influence of the boost pressure difference, the self-learning state of time t1 is changed to downward learning state 1, i.e., r t1 Need to be lowered. t1 =r t1 (z)-0.02, r Boost =r Boost (z) -0.1. CNT2 is cleared at the same time. The newly learned and stored learning value is used the next time the situation is judged. CNT2 is updated at most once during each driving cycle.

[0086] 3. If t1'-t1 is greater than the preset value C1, and the last time t1-t1 was not greater than the preset value -C2, the adjustment fluctuation is too large, and the pressure fluctuation has a greater impact at this time. Then the time t1 self-learning state is changed to upward learning state 2, that is, r t1 Needs to be increased.

[0087] r t1 =r t1 (z) + 0.02. The newly learned and stored learning value is used the next time when entering this situation. 4. If t1'-t1 is not greater than the preset value -C2, and the last time t1-t1 was greater than the preset value C1, the adjustment fluctuation is too large, and the pressure fluctuation has a greater impact at this time, then the time t1 self-learning state is set to the downward learning state 2, that is, r t1 Needs to be lowered.

[0088] r t1 =r t1 (z) -0.02. The newly learned and stored learning value is used the next time the judgment is made in this situation.

[0089] 7. In other cases, t1 and r Boost remain unchanged;

[0090] The priorities of the above 7 conditions are getting lower and lower, and at most one is updated in each driving cycle.

[0091] Furthermore, if the following conditions are met, it is still necessary to update in the current driving cycle:

[0092] 1. If t1'-t1 is greater than the preset value C1 (0.1s in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change exceeds the preset value (0.4 in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen If the knock protection exceeds the preset value (0.9 in this example), and the number of consecutive occurrences CNT3 (initial value is 0, which can be saved after the vehicle is powered off) exceeds the preset value (5 in this example), it means that the knock protection has caused the duration t1 to increase. In order to avoid the excessive oxygen storage in the catalyst causing the generation of NOx, the EGR opening maintenance time needs to be further delayed. The self-learning state of time t1 is set to the upward learning state 1, that is, r t1 Need to increase. t1 =r t1 (z)+0.05, and CNT3 is cleared at the same time. The newly learned and stored learning value is used the next time the situation is judged. CNT3 is updated at most once during each driving cycle.

[0093] 2. If t1'-t1 is greater than the preset value C1 (0.1s in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change exceeds the preset value (0.3 in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen If the number of consecutive occurrences CNT4 (initial value is 0, which can be saved after the vehicle is powered off) exceeds the preset value (5 in this example), it means that the impact of knock protection has caused the duration t1 to increase continuously. Then the self-learning state of time t1 is changed to upward learning state 1, i.e., r t1 Need to increase. t1 =r t1 (z) + 0.025. CNT4 is cleared at the same time. The newly learned and stored learning value is used the next time the situation is judged. CNT4 is updated at most once during each driving cycle.

[0094] 3. If t1'-t1 is greater than the preset value C1 (0.1s in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change exceeds the preset value (0.2 in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen If the number of consecutive occurrences CNT5 (initial value is 0, which can be saved after the vehicle is powered off) exceeds the preset value (5 in this example), the self-learning state at time t1 is changed to upward learning state 1, i.e., r t1 Need to increase. t1 =r t1(z) + 0.01. CNT5 is cleared at the same time. The newly learned and stored learning value is used the next time the situation is judged. CNT5 is updated at most once during each driving cycle.

[0095] 4. If t1'-t1 is greater than the preset value C1 (0.1s in this example), and the number of consecutive occurrences CNT6 (initial value is 0, which can be saved after the vehicle is powered off) exceeds the preset value (5 in this example), the self-learning state of time t1 is changed to upward learning state 1, that is, r t1 Need to increase. t1 =r t1 (z) + 0.005. CNT6 is cleared at the same time. The newly learned and stored learning value is used the next time the situation is judged. CNT6 is updated at most once during each driving cycle.

[0096] 5. If t1'-t1 is not greater than the preset value -C2 (0.1s in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change exceeds the preset value (0.4 in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen If the value exceeds the preset value (0.9 in this example), and the number of consecutive occurrences CNT7 (initial value is 0, which can be saved after the vehicle is powered off) exceeds the preset value (5 in this example), the time t1 self-learning state is changed to downward learning state 1, that is, r t1 Need to be lowered. t1 =r t1 (z) -0.02. CNT7 is cleared at the same time. The newly learned and stored learning value is used the next time the situation is judged. CNT6 is updated at most once during each driving cycle.

[0097] 6. If t1'-t1 is not greater than the preset value -C2 (0.1s in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change exceeds the preset value (0.3 in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen If the number of consecutive occurrences CNT8 (initial value is 0, which can be saved after the vehicle is powered off) exceeds the preset value (5 in this example), the self-learning state at time t1 is changed to downward learning state 1, i.e., r t1 Need to be lowered. t1 =r t1 (z) -0.03. CNT8 is cleared at the same time. The newly learned and stored learning value is used the next time the situation is judged. CNT7 is updated at most once during each driving cycle.

[0098] 7. If t1'-t1 is not greater than the preset value -C2 (0.1s in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygenThe change exceeds the preset value (0.2 in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen If the number of consecutive occurrences CNT9 (initial value is 0, which can be saved after the vehicle is powered off) exceeds the preset value (5 in this example), the time t1 self-learning state is changed to downward learning state 1, that is, r t1 Need to be lowered. t1 =r t1 (z) -0.04. CNT9 is cleared at the same time. The newly learned and stored learning value is used the next time the situation is judged. CNT7 is updated at most once during each driving cycle.

[0099] 8. If t1'-t1 is not greater than the preset value -C2 (0.1s in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change exceeds the preset value (0.2 in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen If the number of consecutive occurrences CNT10 (initial value is 0, which can be saved after the vehicle is powered off) exceeds the preset value (5 in this example), the time t1 self-learning state is changed to downward learning state 1, that is, r t1 Need to be lowered. t1 =r t1 (z) -0.07. CNT10 is cleared at the same time. The newly learned and stored learning value is used the next time the situation is judged. CNT8 is updated at most once during each driving cycle.

[0100] 9. In other cases, t1 Remain unchanged.

[0101] The priorities of the above 9 conditions are getting lower and lower; and at most one is updated in each driving cycle.

[0102] Embodiment 3: Based on the same inventive concept, this embodiment also provides a vehicle electronic device, including a memory, a processor, and a program stored in the memory and executable on the processor, wherein when the processor executes the program, the EGR control method based on improving performance as described above is implemented.

[0103] Embodiment 4: Based on the same inventive concept, this embodiment further provides a manual-automatic vehicle, wherein the vehicle is provided with the vehicle electronic device as described above.

[0104] Furthermore, all parts of the present application that are not described in detail are the same as the prior art or are implemented using the prior art.

[0105] In summary:

[0106] The present invention proposes an EGR control method based on improving performance, by determining the basic time for which the target opening of the EGR valve remains unchanged after the EGR closed-loop exits, and optimizing the remaining time for which the target opening of the EGR valve remains unchanged based on the change in the catalyst oxygen storage coefficient and the change in the air-fuel ratio, the final EGR valve target opening maintenance time after the EGR closed-loop exits is obtained, so as to optimize the control of the target opening of the EGR valve after the EGR closed-loop exits, thereby improving the stability of engine emissions and boost control during the EGR closed-loop exit process.

[0107] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0108] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0109] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0110] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1The steps for the functions specified in one or more boxes.

[0111] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is 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. An EGR control method based on improving performance, characterized in that: include: When it is read that the EGR closed-loop enabling condition changes from being satisfied to being unsatisfied, the pressure ratio coefficient is determined according to the ratio of the actual pressure at the mixing valve outlet to the actual pressure at the mixing valve inlet, and the ratio of the actual pressure at the throttle outlet to the actual pressure at the throttle inlet, and the initial value of the time length during which the EGR valve target opening is maintained unchanged is determined according to the pressure ratio coefficient and the current real-time engine speed; Based on the changes in the catalyst oxygen storage capacity coefficient, the air-fuel ratio coefficient and the mixing valve outlet pressure, and combined with the remaining time self-learning coefficient, the remaining time value for maintaining the target opening of the EGR valve is self-learned and updated for optimization; The target opening maintenance time of the EGR valve after the final EGR closed-loop exit is determined according to the initial time value and the updated and optimized remaining time value.

2. The EGR control method based on improving performance according to claim 1, characterized in that: The initial value t of the time period during which the EGR valve target opening is maintained unchanged is determined by the current engine real-time speed n and the pressure ratio coefficient r PreRatio The pressure ratio coefficient is calculated by the actual pressure p at the outlet of the mixing valve. AfMixAct The actual pressure p of the mixing valve inlet BfMixAct It is calculated by multiplying the ratio by the pressure ratio correction factor.

3. The EGR control method based on improving performance according to claim 1, characterized in that: The calibration basis of the initial value t of the time duration during which the EGR valve target opening is maintained unchanged is: N from the first sampling period when the EGR closed-loop enabling condition is not satisfied to the end of the initial value t of the time duration Boost In a sampling cycle, the difference between the throttle outlet target pressure and the throttle outlet actual pressure p AftThrErr The fluctuation is within the preset range.

4. The EGR control method based on improving performance according to claim 3, characterized in that: Sampling period N Boost is equal to the supercharger response time optimization value τ divided by the preset time value, and the supercharger response time optimization value τ is calculated by the supercharger response time τ Boost Perform self-learning to update and obtain the booster response time τ Boost The self-learning coefficient is r Boost , the supercharger response time τ Boost It is the time required for the mixture to flow from the supercharger compressor to the throttle valve outlet.

5. The EGR control method based on improving performance according to claim 4, characterized in that: The calibration basis for the self-learning update optimization of the remaining time value t1 during which the EGR valve target opening remains unchanged is: the difference between the target boost pressure and the actual boost pressure p is within the preset time period after the remaining time value t1' of the update optimization ends. BoostErr The fluctuation is within the preset range.

6. The EGR control method based on improving performance according to claim 5, characterized in that: The catalyst oxygen storage capacity coefficient r CatalystOxygen The change of Δr CatalystOxygen Take the catalyst oxygen storage capacity coefficient r within the most recent preset number of sampling cycles CatalystOxygen Maximum value and catalyst oxygen storage capacity coefficient r CatalystOxygen Minimum difference, τ EGR is the time required for exhaust gas to flow from the EGR valve to the cylinder, r t1 is the self-learning coefficient of the remaining time value t1.

7. The EGR control method based on improving performance according to claim 6, characterized in that: The supercharger response time τ Boost The self-learning coefficient r Boost and the self-learning coefficient r of the remaining time value t1 t1 The self-learning update process includes: If t1'-t1 is greater than the preset value C1, and the number of consecutive occurrences CNT1 exceeds the preset value CNT0, then r t1 Equal to the r stored in the last learning t1 The learning value plus the preset update value Z1, let r Boost Equal to the r stored in the last learning Boost The learning value plus the preset update value Z2, and clear CNT1 at the same time; If t1'-t1 is not greater than the preset value -C2, and the number of consecutive occurrences CNT2 exceeds the preset value CNT0, then r t1 Equal to the r stored in the last learning t1 The learning value minus the preset update value Z1, let r Boost Equal to the r stored in the last learning Boost The preset update value Z2 is subtracted from the learning value, and CNT2 is cleared to zero.

8. The EGR control method based on improving performance according to claim 7, characterized in that: The self-learning update process further includes: If t1'-t1 is greater than the preset value C1, and t1'-t1 is not greater than the preset value -C2 during the last learning, then let r t1 Equal to the r stored in the last learning t1 The learning value plus the preset update value Z1; If t1'-t1 is not greater than the preset value -C2, and t1'-t1 was greater than the preset value C1 during the last learning, then let r t1 Equal to the r stored in the last learning t1 The preset update value Z1 is subtracted from the learned value.

9. The EGR control method based on improving performance according to claim 8, characterized in that: When the preset condition 1 is met, the self-learning coefficient r of the remaining time value t1 is continued in the current driving cycle. t1 To update: If t1'-t1 is greater than the preset value C1, and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change of Δr CatalystOxygen Exceeds the preset value C3, catalyst oxygen storage capacity coefficient r CatalystOxygen exceeds the preset value C4, and the number of consecutive occurrences of the above condition CNT3 exceeds the preset value CNT0, then r t1 Equal to the r stored in the last learning t1 The learning value is added to the preset update value Z3, and CNT3 is cleared to zero.

10. The EGR control method based on improving performance according to claim 8, characterized in that: When the preset condition 2 is met, the self-learning coefficient r of the remaining time value t1 is continued in the current driving cycle. t1 To update: If t1'-t1 is not greater than the preset value C2, and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change of Δr CatalystOxygen Exceeds the preset value C5, catalyst oxygen storage capacity coefficient r CatalystOxygen exceeds the preset value C6, and the number of consecutive occurrences of the above condition CNT4 exceeds the preset value CNT0, then r t1 Equal to the r stored in the last learning t1 The preset update value Z4 is subtracted from the learning value, and CNT4 is cleared to zero.

11. A vehicle electronic device, comprising a memory, a processor, and a program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the EGR control method based on performance improvement as described in any one of claims 1 to 10 is implemented.

12. A non-transitory readable storage medium having a program stored thereon, characterized in that: When the program is executed by a vehicle electronic device, the EGR control method based on performance improvement as claimed in any one of claims 1 to 10 is implemented.

13. A manual-automatic vehicle, characterized in that: The vehicle electronic device comprising the vehicle electronic device according to claim 11.

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