EGR control method based on improved performance, electronic device and vehicle

Abstract

The present application relates to the technical field of vehicle engine control, in particular to an EGR control method based on performance improvement, an electronic device and a vehicle. The EGR control method based on performance improvement is proposed, the basic duration of maintaining the target opening degree of the EGR valve unchanged after the EGR closed loop is exited is determined, and the remaining duration of maintaining the target opening degree of the EGR valve unchanged is optimized based on the catalyst oxygen storage capacity coefficient change and the air-fuel ratio change, so as to obtain the final EGR valve target opening degree maintenance time after the EGR closed loop is exited, so as to optimize the EGR valve target opening degree control after the EGR closed loop is exited, and then improve the stability of the engine emission and supercharging control in the EGR closed loop exit process.

Description

TECHNICAL FIELD

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

[0002] Exhaust gas recirculation (EGR) takes exhaust gas from the exhaust system into the intake system. Studies have shown that the EGR system has certain advantages in improving emissions, reducing fuel consumption and improving anti-knock ability. The actual EGR rate entering the cylinder is an important basis for the engine to estimate fresh air flow and 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 control of the throttle opening, so that the engine can meet the demand for fresh air volume and meet the power and emission requirements of the vehicle. At the same time, based on the actual EGR rate, the ignition timing will be optimized, thereby improving the power and economy. SUMMARY

[0003] The technical problem to be solved by the present application is to provide an EGR control method based on performance improvement to solve the problems of the prior art. By optimizing the control of the EGR valve target opening after the EGR closed loop exits, the stability of engine emissions and supercharging control during the EGR closed loop exit process can be improved.

[0004] To solve the above technical problems, the technical scheme adopted by the present application is:

[0005] An EGR control method based on performance improvement, comprising the following control strategies:

[0006] S1, when the EGR closed loop enabling condition changes from being satisfied to not being satisfied, determining a pressure ratio coefficient according to the ratio of the actual pressure at the outlet of the hybrid valve to the actual pressure at the inlet of the hybrid valve, and the ratio of the actual pressure at the outlet of the throttle valve to the actual pressure at the inlet of the throttle valve, and determining an initial value of the time length during which the EGR valve target opening is maintained unchanged according to the pressure ratio coefficient and the current engine real-time speed;

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

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

[0009] Further, the initial value of the time length during which the EGR valve target opening is maintained unchanged t=f(r PreRatio ,n), wherein n is the current engine real-time speed, r PreRatiois a pressure ratio coefficient; the pressure ratio coefficient wherein, is a mixed valve outlet actual pressure p AfMixAct is a throttle inlet actual pressure p BfMixAct ratio, is a pressure ratio coefficient correction coefficient, which is obtained according to a throttle outlet actual pressure p AfThrAct is a throttle inlet actual pressure p BfThrAct ratio

[0010] Further, the calibration of the initial value t of the time length during which the EGR valve target opening degree remains unchanged is based on the following: from the first sampling period in which the EGR closed-loop enabling condition is not satisfied to N Boost sampling periods after the initial value t of the time length ends, the difference p AftThrErr between the throttle outlet target pressure and the throttle actual outlet pressure satisfies the following formula:

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

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

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

[0014] Further, wherein, the turbocharger response time optimization value τ=τ Boost ×(1+r Boost ), r Boost is the turbocharger response time τ Boost ​The self-learning coefficient of the remaining time value t1, whose default value is 0 and which can be saved after the vehicle is powered off; the response time τ Boost The time required for the mixed gas to flow from the supercharger compressor to the throttle valve outlet.

[0015] Further, the remaining time value t1, which is kept unchanged, is updated and optimized by self-learning, specifically as follows:

[0016]

[0017] The change amount Δr CatalystOxygen of the catalyst oxygen storage capacity coefficient r CatalystOxygen The latest catalyst oxygen storage capacity coefficient r CatalystOxygen maximum value and the catalyst oxygen storage capacity coefficient r CatalystOxygen minimum value,

[0018] τ EGR The time required for the exhaust gas to flow from the EGR valve to the cylinder, r t1 The self-learning coefficient of the remaining time value t1, whose default value is 0 and which can be saved after the vehicle is powered off.

[0019] In the case of Δr CatalystOx ygen If the pressure ratio r PreRatio is smaller, f(r PreRatio , Δr CatalystOxygen ) is smaller; in the case of the same pressure ratio r PreRatio , if Δr CatalystOxygen is larger, f(r PreRatio , Δr CatalystOxygen ) is larger;

[0020] In the case of Δr CatalystOxygen , if the pressure ratio is smaller, f(Δp , Δr CatalystOxygen ) is smaller; in the case of the same pressure ratio , if Δr CatalystOxygen is larger, f(Δp , Δr CatalystOxygen ) is larger;

[0021] In the case of the same supercharging pressure difference change amount Δp BoostErr , if the mixed valve outlet pressure p AfMixAct change amount Δp AfMixAct is smaller, f(Δp AfMixAct , Δp BoostErr ) is smaller; in the case of the same mixed valve outlet pressure p AfMixAct change amount Δp AfMixAct , if the supercharging pressure difference change amount Δp BoostErr is larger, f(ΔpAfMixAct , Δp BoostErr ) is larger.

[0022] Further, 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:

[0023] 1) If t1'-t1 is greater than a preset value C1, and the number of consecutive occurrences CNT1 exceeds a preset value CNT0, then r t1 is equal to the last learned and stored r t1 learning value plus a preset update value Z1, and r Boost is equal to the last learned and stored r Boost learning value plus a preset update value Z2, and CNT1 is cleared to zero;

[0024] 2) If t1'-t1 is not greater than a preset value -C2, and the number of consecutive occurrences CNT2 exceeds a preset value CNT0, then r t1 is equal to the last learned and stored r t1 learning value minus a preset update value Z1, and r Boost is equal to the last learned and stored r Boost learning value minus a preset update value Z2, and CNT2 is cleared to zero;

[0025] 3) If t1'-t1 is greater than a preset value C1, and the last learning occurred when t1'-t1 was not greater than a preset value -C2, then r t1 is equal to the last learned and stored r t1 learning value plus a preset update value Z1;

[0026] 4) If t1'-t1 is not greater than a preset value -C2, and the last learning occurred when t1'-t1 was greater than a preset value C1, then r t1 is equal to the last learned and stored r t1 learning value minus a preset update value Z1;

[0027] 5) In other cases, r t1 and r Boost remain unchanged.

[0028] Further, if the following conditions are met, then r t1 is updated in the current driving cycle:

[0029] 1) If t1'-t1 is greater than a preset value C1, and the change Δr CatalystOxygen in the catalyst oxygen storage capacity coefficient r CatalystOxygen exceeds a preset value C3, and the catalyst oxygen storage capacity coefficient r CatalystOxygenIf the number of consecutive occurrences exceeds the preset value C4, and the number of occurrences CNT3 exceeds the preset value CNT0, then let r... t1 Equal to the last time we learned how to store r t1 The learned value is added to the preset update value Z3, and CNT3 is cleared to zero.

[0030] 2) If t1'-t1 is not greater than the preset value C2, and the catalytic converter oxygen storage capacity coefficient r CatalystOxygen The change Δr CatalystOxygen Exceeding the preset value C5, the catalytic converter oxygen storage capacity coefficient r CatalystOxygen If the number of consecutive occurrences exceeds the preset value C6, and the number of occurrences CNT4 exceeds the preset value CNT0, then let r... t1 Equal to the last time we learned how to store r t1 The learned value is subtracted from the preset update value Z4, and CNT4 is cleared to zero.

[0031] 3) In other cases, r t1 It remains unchanged.

[0032] Compared with the prior art, the present invention has the following main advantages:

[0033] This invention proposes an EGR control method based on performance improvement. By determining the basic duration for which the target opening of the EGR valve remains unchanged after EGR closed-loop exit, and optimizing the remaining duration for maintaining the target opening of the EGR valve unchanged based on the changes in the catalyst oxygen storage coefficient and the air-fuel ratio, the final target opening duration of the EGR valve after EGR closed-loop exit is obtained. This optimizes the control of the target opening of the EGR valve after EGR closed-loop exit, thereby improving the stability of engine emissions and boost control during EGR closed-loop exit. Attached Figure Description

[0034] Figure 1 This is an overall flowchart of the EGR control method based on performance improvement in Embodiment 1 of the present invention;

[0035] Figure 2 This is a schematic diagram of the EGR system in Embodiment 1 of the present invention;

[0036] Figure 3 This is a schematic diagram of the steps of the EGR control method in Embodiment 2 of the present invention.

[0037] In the diagram: 1. Air filter; 2. Mixing valve; 3. Compressor; 4. Throttle valve; 5. Engine; 6. Turbine; 7. Catalyst; 8. Particulate filter; 9. EGR cooler; 10. EGR valve; 11. Temperature sensor; 12. Differential pressure sensor. Detailed Implementation

[0038] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0039] It should be noted that, according to the needs of implementation, each step / component described in the present application can be split into more steps / components, or two or more steps / components or part of the operation of the steps / components can be combined into a new step / component to achieve the purpose of the present application.

[0040] In the present application, unless otherwise explicitly specified and limited, the terms "first" and "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can include at least one of the features explicitly or implicitly. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0041] Embodiment one, when the EGR system closed loop enabling condition is met, the traditional PID closed loop control algorithm is used to control the action of the mixing valve and the EGR valve to realize the following of the EGR rate; and when the EGR closed loop enabling condition is not met, how to set the target opening of the EGR valve is the main consideration of the present application.

[0042] The present embodiment provides an EGR control method based on improved performance, as shown in Figure 1 The main strategies include the following:

[0043] S1, when the EGR closed loop enabling condition changes from being met to not being met, the pressure ratio coefficient is determined according to the ratio of the actual pressure at the outlet of the mixing valve to the actual pressure at the inlet of the mixing valve, and the ratio of the actual pressure at the outlet of the throttle valve to the actual pressure at the inlet of the throttle valve, and the initial value of the time length during which the target opening of the EGR valve is maintained unchanged is determined according to the pressure ratio coefficient and the current real-time engine speed;

[0044] S2, based on the change amount of the catalyst oxygen storage capacity coefficient, the change amount of the air-fuel ratio coefficient and the change amount of the mixing valve outlet pressure, and combined with the remaining time self-learning coefficient, the remaining time value during which the target opening of the EGR valve is maintained unchanged is self-learned, updated and optimized;

[0045] S3, the final EGR valve target opening maintenance time after the EGR closed loop is exited is determined according to the initial value of the time length and the updated and optimized remaining time value.

[0046] As shown in Figure 2As shown, the EGR system mainly includes:

[0047] An air filter 1, which is connected with a mixing valve 2;

[0048] The mixing valve 2 is used to adjust the pressure at the outlet of the EGR valve 10, to increase the pressure difference between the two ends of the EGR valve 10, and two air flow paths extend from the mixing valve 2;

[0049] A compressor 3 is installed on one of the air flow paths, and an EGR cooler 9 is installed on the other air flow path;

[0050] The compressor 3 is connected with a throttle valve 4, and the throttle valve 4 is connected with an engine 5, which is used to compress fresh air for pressure boosting;

[0051] The engine 5 is connected with a turbine 6, which is used to control the opening degree of the waste gas bypass valve;

[0052] The turbine 6 is connected with a catalytic converter 7, and the catalytic converter 7 is connected with a particulate filter 8;

[0053] The EGR cooler 9 is used to receive and cool the exhaust gas output by the particulate filter 8, to increase the exhaust gas flow;

[0054] The EGR valve 10 is connected with the EGR cooler 9 at one end and the mixing valve 2 at the other end, which is used to control the exhaust gas flow into the cylinder;

[0055] A temperature sensor 11 is installed between the EGR valve 10 and the EGR cooler 9, which is used to detect the temperature of the exhaust gas entering the EGR valve 10;

[0056] A pressure difference sensor 12 is installed between the inlet and outlet of the EGR valve 10, which is used to detect the pressure at the inlet and outlet of the EGR valve 10.

[0057] In the second embodiment, an EGR control method based on performance improvement is provided, as shown, mainly including: Figure 3

[0058] Assuming that the EGR control requirement is maximum, the EGR valve target opening degree pct EGRDsrd is 100%; when the EGR control requirement is minimum, the EGR valve target opening degree pct EGRDsrd is 0%.

[0059] 1) Once the EGR closed-loop enabling condition is met, the EGR valve target opening degree pct EGRDsrd is executed according to the closed-loop control requirement, which is not within the scope of the patent.

[0060] ​2) Once the EGR closed-loop enable condition changes from satisfied to unsatisfied (i.e., it was satisfied in the previous sampling period and is unsatisfied in the current sampling period; the sampling period in this example is 10ms), the actual outlet pressure p of the mixing valve is then used as the basis for determining the EGR closed-loop enable condition. AfMixAct (The outlet pressure of the EGR valve can be used as a substitute or other methods) and the actual inlet pressure p of the mixing valve. BfMixAct ratio Actual throttle outlet pressure p AfThrAct With the actual pressure p at the throttle inlet BfThrAct ratio Together they determine the outlet pressure ratio coefficient r PreRatio And the current real-time engine speed n determines the target opening of the EGR valve pct EGRDsrd The initial value t is maintained constant for a fixed duration to ensure the stability of the EGR valve and prevent any impact on the boost inlet pressure, thus affecting the boost control responsiveness. That is, pct is determined. EGRDsrd =pct EGRDsrd The duration of (z), where pct EGRDsrd (z) represents the target opening of the EGR valve in the previous sampling period, i.e., the target opening of the EGR valve when the EGR closed-loop condition is met in the last sampling period. The initial duration t starts counting from the first sampling period when the EGR closed-loop condition is not met. This is a correction factor for the pressure ratio coefficient, mainly considering... The larger the throttle body, the worse its control capability, and the greater the risk to the turbocharger's pressure control accuracy. To avoid turbocharger pressure control accuracy issues, improvements are needed. Specifically... The query calibration table is as follows:

[0061]

[0062]

[0063] Furthermore, t = f(r) PreRatio The calibration basis for (n) is from the first sampling period when the EGR closed-loop condition is not satisfied to the end of the N period after the initial duration t. Boost Within each sampling period (N) Boost Pick The difference p between the target throttle outlet pressure and the actual throttle outlet pressure. AftThrErr The fluctuations are within the preset range.

[0064] τ=τ Boost ×(1+r Boost ) represents the booster response time. Boost The turbocharger response time τ Boost The self-learning coefficient has a default value of 0 and can be saved after the vehicle is powered off.

[0065] turbocharger response time τ Boost This refers to the time it takes for the air-fuel mixture to flow from the turbocharger compressor to the throttle outlet; this part can be adjusted for different engine speeds (n). eng And different actual intake air densities rho entering the cylinder Act The value of τ is obtained by averaging multiple samples under different EGR rates. Boost It is determined by the engine speed n eng and the actual intake air density rho entering the cylinder Act This can be determined (or obtained directly through bench calibration).

[0066] The basis for this judgment is that, under the condition that the target boost pressure remains constant,

[0067] p BoostErrFilter (N)=K BoostErr ×[p BoostErr (N)-p BoostErrFilter [(N-1)]+p BoostErrFilter (N-1)

[0068] Where, p BoostErr p is the original value of the difference between the target boost pressure and the actual boost pressure. BoostErr (N) represents the pressure difference p during the Nth sampling period. BoostErr Original value, p BoostErrFilter The pressure difference after first-order low-pass filtering, p BoostErrFilter (N) represents the filtered pressure difference after the Nth sampling period, p BoostErrFilter (N-1) represents the filtered pressure difference in the (N-1)th sampling period, where N = 1, 2, 3, ..., p BoostErrFilter (0) equals the pressure difference p during the 0th sampling period. AftThrErr (0), specifically, the 0th sampling period occurs at the EGR system closed-loop enable time; the sampling period interval Δt is 10ms in this example. K BoostErr For coefficients: k BoostErr The pressure difference filter coefficient is 0.2 in this example.

[0069] In |p BoostFilter (N)-p BoostErr (N)|<min[p BoostErr (N), p BoostErrFilter (N)]×r BoostErrLim The condition is defined as follows: from the first sampling period where the EGR closed-loop condition is not satisfied until the end of the Nth period after the initial duration t. Boost If the condition is met within each sampling period, it indicates that the difference p between the target boost pressure and the actual boost pressure is... BoostErrThe fluctuation is within the preset range, where r BoostErrLim In this example, we use 0.1.

[0070] Based on the above calibration criteria, t = f(r) is determined. PreRatio Given the same rotational speed n, if the pressure ratio r PreRatio The smaller the value, the smaller the initial duration t, in order to satisfy the difference p between the target boost pressure and the actual boost pressure. BoostErr The fluctuation is within the preset range; at the pressure ratio r PreRatio Under the same conditions, if the rotational speed n is smaller, the initial duration t will be larger, in order to satisfy the difference p between the target boost pressure and the actual boost pressure. BoostErr The fluctuations are within the preset range;

[0071] The above determines the target opening degree (pct) of the EGR valve. EGRDsrd The initial value t, which remains constant, is mainly obtained through calibration on the engine test bench.

[0072] However, during real-vehicle calibration testing, the remaining time for maintaining the target opening of the EGR valve to remain unchanged needs to be optimized when the following situations occur:

[0073] After the EGR closed-loop enable condition is removed, the target opening degree (pct) of the EGR valve is reached. EGRDsrd Under the condition of keeping constant (i.e., EGR is off but control is in a steady state), based on the catalyst oxygen storage capacity coefficient r CatalystOxygen Change Δr CatalystOxygen air-fuel ratio 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 time to the target opening degree pct of the EGR valve. EGRDsrd The time when the EGR closed-loop enabling condition is maintained at a constant level (t1 is not necessarily equal to t, because changes in boost pressure differential may occur some time after the EGR closed-loop enabling condition has been removed). Air-fuel ratio coefficient. Chinese r ActFuelAir Ratio r is the actual air-fuel ratio. StadFuelAirRatio For the ideal fuel-air ratio, we take 1 / 14.3 in this example.

[0074] Wherein, the oxygen storage capacity coefficient r of the catalyst CatalystOxygen The current oxygen storage capacity coefficient r of the catalyst can be obtained by dividing the current oxygen storage capacity of the catalyst by the maximum oxygen storage capacity. CatalystOxygen The value ranges from 0 to 1. A smaller oxygen storage coefficient indicates a smaller oxygen storage capacity in the catalyst. In this case, the EGR rate can be appropriately reduced, resulting in less NOx production. (Refer to existing patents)

[0075] CN110259553A, "A method, apparatus, and electronic device for calculating the oxygen storage capacity of a three-way catalytic converter," allows for real-time reading of the catalytic converter's oxygen storage capacity; CN104594986A, "A method for diagnosing engine catalytic converter deterioration," allows for real-time reading of the catalytic converter's maximum oxygen storage capacity.

[0076] The mixing valve outlet pressure p AfMixAct Change Δp AfMixAct Take the nearest The mixing valve outlet pressure p before the next sampling period (each sampling period is 10ms) AfMixAct Maximum value and mixing valve outlet pressure p AfMixAct The minimum difference (if the mixing valve outlet pressure p) AfMixAct The time when the maximum value occurs is before the mixing valve outlet pressure p AfMixAct If the minimum value occurs later, the mixing valve outlet pressure p AfMixAct Change Δp AfMixAct It is a positive value; if the mixing valve outlet pressure p AfMixAct The time when the maximum value occurs is before the mixing valve outlet pressure p AfMixAct If the minimum value occurs earlier, the mixing valve outlet pressure p AfMixAct Change Δp AfMixAct It is a negative value; if the mixing valve outlet pressure p AfMixAct The timing of the maximum value occurrence is related to the mixing valve outlet pressure p. AfMixAct If the minimum values ​​occur at the same time, then the mixing valve outlet pressure p AfMixAct Change Δp AfMixAct (0).

[0077] The change in outlet pressure of the mixing valve is considered because if the change is too large, it will have a deteriorating effect on the stability trend of boost control, thereby affecting the stability of subsequent boost pressure control.

[0078] The oxygen storage capacity coefficient r of the catalyst CatalystOxygen The change Δr CatalystOxygen Take the nearest The catalyst oxygen storage capacity coefficient r within each sampling period (each sampling period is 10ms). CatalystOxygen Maximum value and catalyst oxygen storage capacity coefficient r CatalystOxygen The difference in minimum values ​​(if the oxygen storage capacity coefficient of the catalyst is r) CatalystOxygen The time when the maximum value occurs is before the catalytic oxygen storage capacity coefficient r. CatalystOxygen If the minimum value occurs later, the oxygen storage capacity coefficient r of the mixed catalytic converter will be higher. CatalystOxygen Change Δr CatalystOxygen It is a positive value; if the oxygen storage capacity coefficient r of the catalyst is positive. CatalystOxygen The time when the maximum value occurs is before the catalytic oxygen storage capacity coefficient r.CatalystOxygen The time when the minimum value occurs is early, and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change amount Δr CatalystOxygen is negative; if the catalyst oxygen storage capacity coefficient r CatalystOxygen The time when the maximum value occurs is the same as the catalyst oxygen storage capacity coefficient r CatalystOxygen The time when the minimum value occurs is the same, and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change amount Δr CatalystOxygen is 0.

[0079] The catalyst oxygen storage capacity coefficient r CatalystOxygen The change amount and the air-fuel ratio change amount are because if the change amount is too large, it will cause the deterioration of the supercharging control stability trend, thereby affecting the subsequent supercharging pressure control stability.

[0080] τ EGR is the time of exhaust gas flowing from the EGR valve to the cylinder, and this part can be different for different engine speeds n eng and different actual intake densities rho Act into the cylinder, and the average value of multiple sampling data obtained by setting different EGR rates is obtained, so that τ EGR is determined by the engine speed n eng and the actual intake density rho Act into the cylinder (also can be obtained by bench calibration).

[0081] The calibration basis is to ensure that the difference p BoostErr between the target supercharging pressure and the actual supercharging pressure fluctuates within a preset range within a preset time after t1' ends, and the catalyst oxygen storage capacity coefficient r CatalystOxygen does not exceed a preset value, which is 0.9 in this example, and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change amount does not exceed a preset value, which is 0.2 in this example.

[0082] In the case of the same Δr CatalystOxygen , if the pressure ratio r PreRatio is smaller, f(r PreRatio , Δr CatalystOxygen ) is smaller; in the case of the same pressure ratio r PreRatio , if Δr CatalystOxygen is larger, f(r PreRatio , Δr CatalystOxygen ) is larger.

[0083] In the case of the same Δr CatalystOxygen , if the pressure ratio is smaller, f(r , Δr the same case, if Δr CatalystOxygen is larger, then is larger.

[0084] In the boost pressure difference variation Δp BoostErr , the same case, if the mixed valve outlet pressure p AfMixAct variation Δp AfMixAct is smaller, then f(Δp AfMixAct , Δp BoostErr ) is smaller; in the mixed valve outlet pressure p AfMixAct variation Δp AfMixAct , the same case, if the boost pressure difference variation Δp BoostErr is larger, then f(Δp AfMixAct , Δp BoostErr ) is larger.

[0085] Where t1 time limit is between the maximum value tmax (this example takes 0.2s) and the minimum value tmin (this example takes 0s), to avoid the adjustment too large and the intake system control robustness is poor; Where r t1 is the self-learning coefficient of time t1, the default value is 0, and can be saved after the vehicle is powered off.

[0086] Further, the learning value r t1 of time t1 and the self-learning coefficient r Boost of the turbocharger response time τ Boost are learned as follows:

[0087] 1. If t1'-t1 is greater than the preset value C1 (this example takes 0.1s, then it is explained that the adjustment is too large caused by the excessive fluctuation of the boost pressure difference), and Δp AfMixAct exceeds the preset value (this example takes ±20kPa), and the continuous occurrence number CNT1 (the initial value is 0, and can be saved after the vehicle is powered off) exceeds the preset value (this example takes 5), it is explained that the boost pressure difference causes the time t1 to increase all the time, in order to avoid the influence of the fluctuation of the boost pressure difference, the time t1 self-learning state is learned to the upward learning state, that is, r t1 needs to be increased. r t1 =r t1 (z)+0.02, r Boost =r Boost (z)+0.1, where r t1 (z) is the time t1 learning value stored in the last learning, r Boost (z) is the r Boost learning value stored in the last learning. At the same time, CNT1 is cleared. The new learning value stored in the learning is used next time when this kind of situation is judged. CNT1 is updated at most once in each driving cycle.

[0088] 2. If t1'-t1 is not greater than the preset value -C2 (0.1s in this example), it indicates that the adjustment is too large due to excessive fluctuation in the boost pressure difference, and Δp AfMixAct If the value exceeds the preset value (±10 kPa in this example) and the number of consecutive occurrences CNT2 (initially 0, but can be saved after the vehicle is powered off) exceeds the preset value (5 in this example), it indicates that the influence of the boost pressure difference is causing the duration t1 to continuously decrease. To avoid reducing the impact on the fluctuation of the boost pressure difference, the time t1 is set to the downward learning state one, i.e., r t1 It needs to be reduced. t1 =r t1 (z)-0.02, r Boost =r Boost (z)-0.1. Simultaneously, CNT2 is cleared to zero. The newly learned value is used the next time this condition is considered. CNT2 is updated at most once per driving cycle.

[0089] 3. If t1'-t1 is greater than the preset value C1, and the previous occurrence of t1-t1 was not greater than the preset value -C2, then the adjustment fluctuation is too large, which has a significant impact on pressure fluctuation. In this case, the self-learning state of time t1 is changed to the upward learning state two, i.e., r t1 It needs to be increased.

[0090] r t1 =r t1 (z)+0.02. The newly learned value is used when this condition is considered again.

[0091] 4. If t1'-t1 is not greater than the preset value -C2, and the previous occurrence of t1-t1 was greater than the preset value C1, then the adjustment fluctuation is too large, which has a significant impact on pressure fluctuation. In this case, the self-learning state of time t1 is changed to the downward learning state two, i.e., r t1 It needs to be reduced.

[0092] r t1 =r t1 (z)-0.02. The newly learned value is used when judging this situation the next time it is entered.

[0093] 7. In other cases, r t1 and r Boost Remain unchanged;

[0094] The priority of the above 7 conditions decreases from one to the next. And at most one condition can be updated per driving cycle.

[0095] Furthermore, updates will still be performed in the current driving cycle if the following conditions are met:

[0096] 1, if t1'-t1 is greater than preset value C1 (0.1s in this example), and catalyst oxygen storage capacity coefficient r CatalystOxygen changes by more than a preset value (0.4 in this example), and catalyst oxygen storage capacity coefficient r CatalystOxygen exceeds a preset value (0.9 in this example), and the number of consecutive occurrences CNT3 (initial value 0, which can be saved after the vehicle is powered off) exceeds a preset value (5 in this example), it is indicated that the knock protection effect causes the time t1 to always increase, and in order to avoid the catalyst oxygen storage amount being too high to cause the generation of NOx, the time t1 self-learning state is set to the upward learning state, i.e. r t1 needs to be increased. r t1 =r t1 (z)+0.05, and CNT3 is cleared. The newly learned storage learning value is used next time the condition is entered. CNT3 is updated at most once during each driving cycle.

[0097] 2, if t1'-t1 is greater than preset value C1 (0.1s in this example), and catalyst oxygen storage capacity coefficient r CatalystOxygen changes by more than a preset value (0.3 in this example), and catalyst oxygen storage capacity coefficient r CatalystOxygen exceeds a preset value (0.9 in this example), and the number of consecutive occurrences CNT4 (initial value 0, which can be saved after the vehicle is powered off) exceeds a preset value (5 in this example), it is indicated that the knock protection effect causes the time t1 to always increase, and in order to avoid the catalyst oxygen storage amount being too high to cause the generation of NOx, the time t1 self-learning state is set to the upward learning state, i.e. r t1 needs to be increased. r t1 =r t1 (z)+0.025. CNT4 is cleared at the same time. The newly learned storage learning value is used next time the condition is entered. CNT4 is updated at most once during each driving cycle.

[0098] 3, if t1'-t1 is greater than preset value C1 (0.1s in this example), and catalyst oxygen storage capacity coefficient r CatalystOxygen changes by more than a preset value (0.2 in this example), and catalyst oxygen storage capacity coefficient r CatalystOxygen exceeds a preset value (0.9 in this example), and the number of consecutive occurrences CNT5 (initial value 0, which can be saved after the vehicle is powered off) exceeds a preset value (5 in this example), the time t1 self-learning state is set to the upward learning state, i.e. r t1 needs to be increased. r t1 =r t1 (z)+0.01. CNT5 is cleared at the same time. The newly learned storage learning value is used next time the condition is entered. CNT5 is updated at most once during each driving cycle.

[0099] 4. If t1'-t1 is greater than preset value C1 (0.1 s in this example), and the number of consecutive occurrences CNT6 (initial value 0, which can be saved after the vehicle is powered off) exceeds a preset value (5 in this example), the time t1 self-learning state is set to the upward learning state, i.e., r t1 needs to be increased. r t1 = r t1 (z) + 0.005. At the same time, CNT6 is cleared. The newly learned stored learning value is used next time when this kind of condition is judged. CNT6 is updated at most once during each driving cycle.

[0100] 5. If t1'-t1 is not greater than preset value -C2 (0.1 s in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen changes by more than a preset value (0.4 in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen exceeds a preset value (0.9 in this example), and the number of consecutive occurrences CNT7 (initial value 0, which can be saved after the vehicle is powered off) exceeds a preset value (5 in this example), the time t1 self-learning state is set to the downward learning state, i.e., r t1 needs to be decreased. r t1 = r t1 (z) - 0.02. At the same time, CNT7 is cleared. The newly learned stored learning value is used next time when this kind of condition is judged. CNT6 is updated at most once during each driving cycle.

[0101] 6. If t1'-t1 is not greater than preset value -C2 (0.1 s in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen changes by more than a preset value (0.3 in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen exceeds a preset value (0.9 in this example) and the number of consecutive occurrences CNT8 (initial value 0, which can be saved after the vehicle is powered off) exceeds a preset value (5 in this example), the time t1 self-learning state is set to the downward learning state, i.e., r t1 needs to be decreased. r t1 = r t1 (z) - 0.03. At the same time, CNT8 is cleared. The newly learned stored learning value is used next time when this kind of condition is judged. CNT7 is updated at most once during each driving cycle.

[0102] 7. If t1'-t1 is not greater than preset value -C2 (0.1 s in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygen changes by more than a preset value (0.2 in this example), and the catalyst oxygen storage capacity coefficient r CatalystOxygenIf the number of consecutive occurrences exceeds a preset value (0.9 in this example) CNT9 (initial value is 0, which can be saved after the vehicle is powered off) and exceeds a preset value (5 in this example), then the self-learning state of time t1 will be changed to the downward learning state one, i.e., r t1 It needs to be reduced. t1 =r t1 (z)-0.04. Simultaneously, CNT9 is cleared. The newly learned value is used the next time this condition is considered. CNT7 is updated at most once per driving cycle.

[0103] 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 exceeds a preset value (0.9 in this example) CNT10 (initially 0, can be saved after the vehicle is powered off) and exceeds a preset value (5 in this example), then the self-learning state of time t1 will be changed to downward learning state one, i.e., r t1 It needs to be reduced. t1 =r t1 (z)-0.07. Simultaneously, CNT10 is cleared. The newly learned value is used the next time this condition is considered. CNT8 is updated at most once per driving cycle.

[0104] 9. In other cases, r t1 It remains unchanged.

[0105] The priority of the above 9 conditions decreases progressively; and at most one condition can be updated in each driving cycle.

[0106] Example 3: Based on the same inventive concept, this example also provides a vehicle electronic device, including a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, it implements the EGR control method based on improved performance as described above.

[0107] Example 4: Based on the same inventive concept, this example also provides a manual / automatic vehicle, which is equipped with the vehicle electronic equipment described above.

[0108] Furthermore, all parts of this application that are not described in detail are the same as or implemented using existing technology.

[0109] In summary:

[0110] The application provides an EGR control method based on improved performance, which comprises the following steps: determining a basic time length during which the target opening degree of the EGR valve is maintained unchanged after the EGR closed loop is exited, and optimizing the remaining time length during which the target opening degree of the EGR valve is maintained unchanged based on the oxygen storage capacity coefficient change amount and the air-fuel ratio change amount of the catalyst, so as to obtain the final EGR valve target opening degree maintenance time after the EGR closed loop is exited, so that the EGR valve target opening degree control after the EGR closed loop is exited is optimized, and the stability of engine emission and supercharging control during the EGR closed loop exit process is improved.

[0111] Those skilled in the art will understand that embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code.

[0112] The present application is described with reference to flowcharts and / or block diagrams according to the methods, devices (systems), and computer program products of the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the computer or other programmable data processing apparatus generate a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0113] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including instruction devices that implement the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0114] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable data processing apparatus to produce a computer-implemented process, so that the instructions executed on the computer or other programmable data processing apparatus provide a device for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1steps of the functions specified in the block or blocks.

[0115] It is readily understood by those skilled in the art that the above description is only preferred embodiments of the application, and is not intended to limit the application. Any modification, equivalent replacement and improvement made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. An EGR control method based on performance improvement, characterized in that, include: When the EGR closed-loop enabling condition changes from satisfied to unsatisfied, the pressure ratio coefficient is determined based on the ratio of the actual pressure at the outlet of the mixing valve to the actual pressure at the inlet of the mixing valve, and the ratio of the actual pressure at the outlet of the throttle valve to the actual pressure at the inlet of the throttle valve. Based on the pressure ratio coefficient and the current real-time engine speed, the initial value of the duration for which the target opening of the EGR valve remains unchanged is determined. 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, updated, and optimized. Based on the initial duration value and the updated and optimized remaining time value, the final EGR valve target opening maintenance time after EGR closed-loop exit is determined.

2. The EGR control method based on performance improvement according to claim 1, characterized in that, The initial value t for maintaining the target opening of the EGR valve unchanged is determined by the current real-time engine speed n and the pressure ratio coefficient r. PreRatio The pressure ratio coefficient is obtained through calculation, and is derived from the actual outlet pressure p of the mixing valve. AfMixAct The actual pressure p at the inlet of the mixing valve BfMixAct The ratio is calculated by multiplying the pressure ratio coefficient by the correction factor.

3. The EGR control method based on performance improvement according to claim 1, characterized in that, The initial value t for maintaining the target opening of the EGR valve unchanged is calibrated based on: N from the first sampling period when the EGR closed-loop enable condition is not met to the end of the initial value t. Boost Within each sampling period, the difference p between the target throttle outlet pressure and the actual throttle outlet pressure. AftThrErr The fluctuations are within the preset range.

4. The EGR control method based on performance improvement according to claim 3, characterized in that, Sampling period N Boost The optimized turbocharger response time τ is equal to the turbocharger response time value τ divided by the preset time value, and the optimized turbocharger response time τ is equal to the turbocharger response time τ. Boost The booster response time τ is obtained through self-learning updates. Boost The self-learning coefficient is r Boost The booster response time τ Boost This is the time required for the air-fuel mixture to flow from the turbocharger compressor to the throttle outlet.

5. The EGR control method based on performance improvement according to claim 4, characterized in that, The calibration basis for self-learning and updating the remaining time value t1 for maintaining the target opening of the EGR valve unchanged is: within a preset time period after the end of the updated and optimized remaining time value t1', the difference p between the target boost pressure and the actual boost pressure. BoostErr The fluctuations are within the preset range.

6. The EGR control method based on performance improvement according to claim 5, characterized in that, The oxygen storage capacity coefficient r of the catalyst CatalystOxygen The change Δr CatalystOxygen Take the nearest Catalyst oxygen storage capacity coefficient r during the next sampling period CatalystOxygen Maximum value and catalyst oxygen storage capacity coefficient r CatalystOxygen The difference between the minimum values, τ EGR r is the time required for exhaust gas to flow from the EGR valve to the cylinder. t1 The self-learning coefficient is the remaining time value t1.

7. The EGR control method based on performance improvement according to claim 6, characterized in that, The booster response time τ Boost Self-learning coefficient r Boost 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 let r t1 Equal to the last time we learned about storage r t1 The learning value is added to the preset update value Z1, so that r Boost Equal to the last time we learned about storage r Boost The learned value is added to the preset update value Z2, and CNT1 is cleared to zero. If t1'-t1 is not greater than the preset value -C2, and the number of consecutive occurrences CNT2 exceeds the preset value CNT0, then let r t1 Equal to the last time we learned about storage r t1 The learning value is subtracted from the preset update value Z1, and r is set to... Boost Equal to the last time we learned about storage r Boost The learned value is subtracted from the preset update value Z2, and CNT2 is cleared to zero.

8. The EGR control method based on performance improvement according to claim 7, characterized in that: The self-learning update process also includes: If t1'-t1 is greater than the preset value C1, and the last time t1'-t1 occurred, it was not greater than the preset value -C2, then let r t1 Equal to the last time we learned about storage r t1 The learning value is added to 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 process, then let r t1 Equal to the last time we learned about storage r t1 The learning value is subtracted from the preset update value Z1.

9. The EGR control method based on performance improvement according to claim 8, characterized in that, When the preset condition is met, the self-learning coefficient r of the remaining time value t1 continues in the current driving cycle. t1 Update: If t1'-t1 is greater than the preset value C1, and the catalyst oxygen storage capacity coefficient r CatalystOxygen The change Δr CatalystOxygen Exceeding the preset value C3, the catalytic converter oxygen storage capacity coefficient r CatalystOxygen If the number of consecutive occurrences of the above condition exceeds the preset value C4, and the number of times CNT3 exceeds the preset value CNT0, then let r t1 Equal to the last time we learned about storage r 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 performance improvement according to claim 8, characterized in that, When the second preset condition is met, the self-learning coefficient r of the remaining time value t1 continues in the current driving cycle. t1 Update: If t1'-t1 is not greater than the preset value C2, and the catalytic converter oxygen storage capacity coefficient r CatalystOxygen The change Δr CatalystOxygen Exceeding the preset value C5, the catalytic converter oxygen storage capacity coefficient r CatalystOxygen If the number of consecutive occurrences of the above condition exceeds the preset value C6, and the number of times CNT4 exceeds the preset value CNT0, then let r t1 Equal to the last time we learned about storage r t1 The learned value is subtracted from the preset update value Z4, 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, it implements the performance-improving EGR control method as described in any one of claims 1 to 10.

12. A non-transitory readable storage medium having a program stored thereon, characterized in that, When executed by the vehicle's electronic equipment, the program implements the performance-enhancing EGR control method as described in any one of claims 1 to 10.

13. A vehicle with both manual and automatic transmissions, characterized in that: Includes the vehicle electronic equipment as described in claim 11.

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