Engine performance improvement control method based on aging loss improvement

Abstract

The invention discloses an engine performance improvement control method based on aging loss improvement, and the method comprises the steps: obtaining a minimum EGR rate original value, and obtaining a minimum EGR rate filtering value according to the minimum EGR rate original value; the minimum EGR rate used for EGR enabling condition judgment is determined according to the minimum EGR rate original value and the minimum EGR rate filtering value; determining whether an EGR closed loop enabling minimum EGR rate condition is met or not according to the minimum EGR rate; and when the EGR closed loop enabling minimum EGR rate condition is met, whether the EGR closed loop is enabled or not is judged according to the EGR closed loop enabling condition. According to the method, the minimum EGR rate is optimized, the EGR rate is optimized to enter the area range of the minimum EGR rate, the EGR enabling condition judgment method is optimized, the oscillation probability of a control actuator is reduced, the EGR system is improved, and the stability of the system is improved.

Description

Technical Field

[0001] The invention relates to the field of engine control, and in particular to a control method for improving engine performance based on improving aging loss. Background Art

[0002] The invention relates to the field of engine control, and more particularly to a method for improving engine performance control based on improving aging loss.

[0003] 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 control of the mixing valve in the low-pressure EGR system is particularly important as it improves the effect of the EGR rate.

[0004] Due to system hysteresis, when the EGR rate enters its minimum EGR rate region, it may cause control actuator oscillation, or even EGR system instability. In the prior art, the target EGR rate is calculated and the target EGR rate is corrected twice, or the target opening of the mixing valve is corrected according to various operating parameters, but the method of optimizing the minimum EGR rate and optimizing the judgment of EGR enabling conditions is usually not considered. Summary of the invention

[0005] In order to optimize the minimum EGR rate and the method for determining the EGR enabling condition, the present invention proposes a control method for improving engine performance based on improving aging loss.

[0006] To this end, the technical solution adopted in the present invention is:

[0007] A control method for improving engine performance based on improving aging loss, the method comprising:

[0008] Obtaining a minimum EGR rate original value, and obtaining a minimum EGR rate filtered value according to the minimum EGR rate original value;

[0009] Determining a minimum EGR rate for judging an EGR enabling condition according to a minimum EGR rate original value and a minimum EGR rate filtered value;

[0010] Determining whether the minimum EGR rate condition for enabling EGR closed loop is met according to the minimum EGR rate;

[0011] When the minimum EGR rate condition for enabling the EGR closed loop is met, whether the EGR closed loop is enabled is determined according to the EGR closed loop enabling condition.

[0012] According to the above scheme, the minimum EGR rate filtered value is specifically obtained by multiplying the difference between the minimum EGR rate original value and the minimum EGR rate filtered value obtained in the previous sampling period by the sampling period interval, divided by the minimum EGR rate filtering time, and adding the minimum EGR rate filtered value obtained in the previous sampling period.

[0013] According to the above scheme, the minimum EGR rate filtering time is specifically obtained by the following method:

[0014] When the preset conditions are met, the minimum EGR rate filter time is equal to the sum of the minimum EGR rate filter time self-learning correction coefficient and 1, multiplied by the product of the boost pressure fluctuation correction coefficient and the engine torque fluctuation correction coefficient and the preset filter time;

[0015] In other cases, the minimum EGR rate filtering time is equal to the preset filtering time.

[0016] According to the above scheme, the preset conditions are specifically:

[0017] The engine torque fluctuation correction factor or the boost pressure fluctuation correction factor is not equal to 1.

[0018] According to the above scheme, the boost pressure fluctuation correction coefficient is determined based on the boost pressure difference original value and the boost pressure difference filtered value;

[0019] If the absolute value of the difference between the boost pressure difference filtered value and the boost pressure difference divided by the minimum value among the boost pressure difference original value, the boost pressure difference filtered value and the preset value is greater than a certain value for a continuous time exceeding the preset time, the boost pressure fluctuation correction coefficient is obtained by calibration, otherwise the boost pressure fluctuation correction coefficient is equal to 1.

[0020] According to the above scheme, the engine torque fluctuation correction coefficient is determined according to the torque difference and the torque difference filter value; the torque difference is the difference between the engine requested fire circuit torque and the actual fire circuit torque;

[0021] If the absolute value of the difference between the torque difference filter value and the torque difference divided by the minimum value among the torque difference, the torque difference filter value and the preset value is greater than a certain value for a continuous time exceeding the preset time, the engine torque fluctuation correction coefficient is obtained by calibration, otherwise the engine torque fluctuation correction coefficient is equal to 1.

[0022] According to the above scheme, the minimum EGR rate determined for judging the EGR enabling condition is specifically:

[0023] When any special demand condition is met, the minimum EGR rate is equal to the original value of the minimum EGR rate;

[0024] In other cases, the minimum EGR rate is equal to the minimum EGR rate filtered value.

[0025] According to the above scheme, the special demand working conditions are specifically as follows:

[0026] Special demand condition 1:

[0027] The difference between the ignition angle efficiency and the ignition angle efficiency of the previous sampling period is within a preset range or the ignition angle efficiency exceeds a preset value;

[0028] There is no fuel cut-off request from the engine;

[0029] The engine did not experience any knock and pre-ignition;

[0030] The engine fresh air intake density fluctuation does not exceed the preset range;

[0031] When all the above conditions are met simultaneously for a continuous time exceeding the preset time, it indicates that the special demand condition is met;

[0032] Special demand condition 2:

[0033] The difference between the air-fuel ratio and the air-fuel ratio of the previous sampling period exceeds the preset value;

[0034] There is no fuel cut-off request from the engine;

[0035] The engine intake air temperature exceeds the preset value;

[0036] The engine water temperature exceeds the preset value;

[0037] When the continuous time that all the above conditions are met simultaneously exceeds the preset time, it indicates that the special demand condition 2 is met.

[0038] According to the above scheme, whether the minimum EGR rate condition for enabling EGR closed loop is met is determined according to the minimum EGR rate:

[0039] When the difference between the target EGR rate and the minimum EGR rate is greater than a preset value of one, the EGR closed loop enabling minimum EGR rate condition is met;

[0040] When the difference between the target EGR rate and the minimum EGR rate is not greater than the preset value 2, and the absolute value of the difference between the target EGR rate and the actual EGR rate is not greater than the preset value 3, the EGR closed loop enabling minimum EGR rate condition is not met;

[0041] In other cases, the EGR closed loop enabling minimum EGR rate condition maintains the previous state, where the vehicle is powered on and is in the default state, and the default state is that the EGR closed loop enabling minimum EGR rate condition is not met.

[0042] According to the above scheme, judging whether the EGR closed loop is enabled according to the EGR closed loop enabling condition is as follows:

[0043] There were no malfunctions related to the EGR system parts;

[0044] No fuel cut request occurs and the fuel cut recovery time exceeds the preset time;

[0045] The minimum EGR rate condition for EGR closed loop is met;

[0046] The engine speed is within the preset speed range;

[0047] The intake air temperature is within the preset range;

[0048] The engine water temperature is within the preset range;

[0049] The atmospheric temperature is within the preset range;

[0050] Atmospheric pressure exceeds the preset pressure value.

[0051] According to the above scheme, the minimum EGR rate filter time self-learning correction coefficient is obtained specifically in the following way:

[0052] When any of the following conditions is met, the minimum EGR rate filter time self-learning correction coefficient is updated:

[0053] Case 1:

[0054] EGR closed loop is enabled, and the EGR closed loop enabling time does not exceed the preset time;

[0055] The boost pressure fluctuation correction coefficient is greater than a certain value for a continuous period exceeding a preset time;

[0056] The engine torque fluctuation correction coefficient is greater than a certain value for a continuous period exceeding a preset time;

[0057] The difference between the target EGR rate and the current minimum EGR rate does not exceed a preset value;

[0058] The accumulated mileage of the engine whose self-learning coefficient is not updated exceeds the preset value;

[0059] When all the above conditions are met, it means that situation 1 is met;

[0060] Case 2:

[0061] The time from the activated state to the inactivated state of the EGR closed loop enabling state does not exceed the preset time;

[0062] The EGR closed loop enable state activation time exceeds the preset time;

[0063] Request the fire circuit torque fluctuation to be within the preset range;

[0064] The target boost pressure fluctuation is within a preset range;

[0065] The accumulated mileage of the engine whose self-learning coefficient is not updated exceeds the preset value;

[0066] When the EGR closed loop enabling minimum EGR rate condition is not met, the EGR closed loop enabling state enters the inactive state;

[0067] When all the above conditions are met, it means that situation 2 is met.

[0068] According to the above scheme, when the first condition is met, the average value of the absolute value of the ratio of the difference between the target EGR rate and the actual EGR rate within a certain period of time after the EGR closed-loop enable is activated and the target EGR rate is read. If the average value is not greater than the preset value, the updated minimum EGR rate filter time self-learning correction coefficient is equal to the sum of the last updated minimum EGR rate filter time self-learning correction coefficient and the change value;

[0069] If the average value is greater than the preset value, the number of times the average value is greater than the preset value is recorded; if the number of times the average value is greater than the preset value is greater than the preset number, and in the process of increasing the number, the first condition is not satisfied, then the updated minimum EGR rate filter time self-learning correction coefficient is equal to the difference between the last updated minimum EGR rate filter time self-learning correction coefficient and the change value;

[0070] In other cases that satisfy condition 1, the updated minimum EGR rate filter time self-learning correction coefficient is equal to the last updated minimum EGR rate filter time self-learning correction coefficient;

[0071] When the second condition is met, the average value 1 of the boost pressure fluctuation correction coefficient and the average value 1 of the engine torque fluctuation correction coefficient during the activation state time before the EGR closed-loop enabling state enters the inactive state are read, and the average value 2 of the boost pressure fluctuation correction coefficient and the average value 2 of the engine torque fluctuation correction coefficient during the inactive state time after the EGR closed-loop enabling state enters the inactive state are read. If the preset value 1 is greater than the average value 2 of the boost pressure fluctuation correction coefficient and less than the average value 1 of the boost pressure fluctuation correction coefficient, and the preset value 2 is greater than the average value 2 of the engine torque fluctuation correction coefficient and less than the average value 1 of the engine torque fluctuation correction coefficient, then the updated minimum EGR rate filter time self-learning correction coefficient is equal to the last updated minimum EGR rate filter time self-learning correction coefficient minus 0.1;

[0072] If the preset value one is less than the average value two of the boost pressure fluctuation correction coefficient and greater than the average value one of the boost pressure fluctuation correction coefficient, and the preset value two is less than the average value two of the engine torque fluctuation correction coefficient and greater than the average value one of the engine torque fluctuation correction coefficient, then the updated minimum EGR rate filter time self-learning correction coefficient is equal to the last updated minimum EGR rate filter time self-learning correction coefficient plus 0.12;

[0073] In other cases where condition 2 is satisfied, the updated minimum EGR rate filter time self-learning correction coefficient is equal to the last updated minimum EGR rate filter time self-learning correction coefficient.

[0074] A computer-readable storage medium stores a computer program, wherein the computer program includes executable instructions. When the executable instructions are executed by a processor, the engine performance improvement control method based on improving aging loss as described above is implemented.

[0075] The beneficial effects produced by the present invention are:

[0076] The present invention optimizes the minimum EGR rate, optimizes the region where the EGR rate enters the minimum EGR rate, optimizes the method for determining the EGR enabling condition, reduces the oscillation probability of the control actuator, improves the EGR system, and improves the stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 A method flow chart of an embodiment of the present invention;

[0078] Figure 2 This is a schematic diagram of the structure of a system with EGR according to another embodiment of the present invention.

[0079] In the figure, 1-air filter; 2-mixing valve; 3-compressor; 4-throttle; 5-engine; 6-turbine; 7-catalyst; 8-particulate matter collector; 9-EGR cooler; 10-EGR valve; 11-temperature sensor; 12-differential pressure sensor. DETAILED DESCRIPTION

[0080] In order to make the purpose, technical solution 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 used to limit the present invention.

[0081] The present invention proposes a control method for improving engine performance based on improving aging loss, such as Figure 1 As shown, the method specifically includes:

[0082] S1. Obtaining an original value of the minimum EGR rate, and obtaining a filtered value of the minimum EGR rate according to the original value of the minimum EGR rate.

[0083] Minimum EGR rate original value r EGRRateMinRaw Specifically, the minimum EGR rate finally obtained in patent CN202211212260.6 "Minimum EGR rate adjustment method, device, equipment and storage medium" can be used as the original value of the minimum EGR rate.

[0084] Minimum EGR rate filter value rEGRRateMinFilt The calculation method is:

[0085]

[0086] Among them, r EGRRateMinFilt (z) is the minimum EGR rate filtered value obtained in the previous sampling period, and its default value is equal to the minimum EGR rate original value r at the same time. EGRRateMinRaw ; T EGRRateMinFilter is the minimum EGR rate filtering time; Δt is the sampling cycle interval.

[0087] Among them, the minimum EGR rate filtering time T EGRRateMinFilter The calculation method is:

[0088] When the following preconditions are met: TrqErr or BoostErr When it is not equal to 1, T EGRRateMinFilter =T0×r Tr q E rr×r B oost E rr×(1+r A dapt)

[0089] In other cases, T EGRRateMinFilter =T0

[0090] Among them, T0 is the preset period, which is 0.04s in this example; r BoostErr is the boost pressure fluctuation correction coefficient; r TrqErr is the engine torque fluctuation correction coefficient, r Adapt It is the self-learning correction coefficient of the minimum EGR rate filter time. Its default value is 0 and it can be saved after the vehicle is powered off.

[0091] The boost pressure fluctuation correction coefficient is determined according to the boost pressure difference and the boost pressure difference filter value difference:

[0092] p BoostErrFilter (N) = K BoostErr ×[p BoostErr (N)-p BoostErrFilter (N-1)]+p BoostErrFilter (N-1)

[0093] Among them, p BoostErr is the boost pressure difference (i.e., the difference between the target boost pressure and the actual boost pressure, which is 0 by default when the boost closed-loop control is not enabled), p BoostErr (N) is the boost pressure difference of the Nth sampling period, p BoostErrFilter is the boost pressure difference after first-order low-pass filtering, p B oost E rrF ilter(N) is the filtered boost pressure difference of the Nth sampling period, p BoostErrFilter (N-1) is the boost pressure difference of the N-1th sampling period, N = 1, 2, 3..., where p BoostErrFilter (0) is equal to the boost pressure difference p at the 0th sampling cycle BoostErr (0), which occurs when the vehicle is powered on; the sampling period interval in this example is 10ms; K BoostErr is the coefficient, Where m is the number of engine cylinders, n is the engine speed, k BoostErr is the boost pressure difference filter coefficient. In this example, the boost pressure difference filter coefficient is 0.03, the number of engine cylinders is 4, and k BoostErr The calibrated speed is 1000rpm. The purpose of setting is normalization. Under different cylinder numbers and speeds, no special calibration is required. Only the k of the 4-cylinder engine and the speed of 1000rpm needs to be calibrated. BoostErr , thereby reducing calibration testing work.

[0094] Get boost pressure difference filter value p BoostErrFilter After that, judge Whether the continuous satisfaction time exceeds the preset value t1, if the continuous satisfaction time does not exceed t1, then r BoostErr is 1; if the continuous satisfaction time exceeds t1, then In this embodiment, k1 is 0.02, t1 is 0.08s, Obtained by calibration, as shown in the following table:

[0095]

[0096] That is, when the boost pressure difference does not change much, the filtering time is not adjusted. The filtering time is increased to avoid further aggravation of boost pressure fluctuations caused by fluctuations in the minimum EGR rate.

[0097] Engine torque fluctuation correction factor r TrqErr Determine based on the difference between the torque difference and the torque difference filter value:

[0098]

[0099] Among them, M TrqErr M is the difference between the engine's requested torque and the actual torque (torque difference for short), TrqErr (N) is the torque difference of the Nth sampling period, M TrqErrFilter is the torque difference after first-order low-pass filtering, M TrqErrFilter (N) is the torque difference after filtering in the Nth sampling period, M TrqErrFilter(N-1) is the filtered torque difference of the N-1th sampling period, N = 1, 2, 3..., where M TrqErrFilter (0) is equal to the torque difference M at the 0th sampling period TrqErr (0), which occurs when the vehicle is powered on, and the default value is 0; the sampling period interval is 10ms in this example; K TrqErr is the coefficient, Where m is the number of engine cylinders, n is the engine speed, in this example the number of engine cylinders is 4, k TrqErr The calibration speed is 1000rpm, k TrqErr is the torque difference filter coefficient, which is 0.08 in this example.

[0100] Get the torque difference filter value M TrqErrFilter After that, judge Whether the continuous satisfaction time exceeds the preset value t2, if the continuous satisfaction time does not exceed t2, then r TrqErr is 1; if the continuous satisfaction time exceeds t1, then In this embodiment, k2 is 0.03, t2 is 0.05s, Obtained by calibration, as shown in the following table:

[0101]

[0102] Finally, the minimum EGR rate filtering value r EGRRateMinFilt Force the setting to be between 0.03s and 0.3s to avoid excessive regulation.

[0103] Minimum EGR rate filter time self-learning correction coefficient r Adapt Updates are performed when the following preset conditions are met:

[0104] Default situation 1:

[0105] When the following conditions are met:

[0106] The EGR closed loop is enabled, and the EGR closed loop enabling time does not exceed the preset time, which is 0.1s in this example;

[0107] r BoostErr >k1 continuously meets the time limit exceeding the preset value t1;

[0108] r TrqErr >k2 continuously meets the time limit exceeding the preset value t2;

[0109] The difference between the target EGR rate and the current minimum EGR rate does not exceed a preset value, and in this embodiment, the preset value is 0.01;

[0110] The accumulated mileage of the engine whose self-learning coefficient is not updated exceeds a preset value, which is 20,000 kilometers in this example.

[0111] When the above conditions are met at the same time, read the average absolute value of the ratio of the target EGR rate to the actual EGR rate within a certain period of time after the EGR closed loop is activated. EGRRatioErrAvg , if it appears:

[0112] (1)r EGRRatioErrAvg Not greater than the preset value, in this example it is 0.015, then f1(r BoostErr ) is r BoostErr Correction factor 1, f1(r TrqErr ) is r TrqErr Correction factor 1, f1(r EGRRatioErrAvg ) is r EGRRatioErrAvg Correction coefficient, where f1(r BoostErr )、f1(r TrqErr ) and f2(r BoostErrAvg ) is obtained by calibration:

[0113] <![CDATA[r BoostErr ]]> 0.02 0.05 0.08 0.12 0.15 0.23 <![CDATA[f1(r BoostErr )]]> 1 1.02 1.05 1.06 1.08 1.1

[0114] <![CDATA[r TrqErr ]]> 0.03 0.05 0.08 0.12 0.14 0.16 <![CDATA[f1(r TrqErr )]]> 0.01 0.01 0.015 0.018 0.02 0.025

[0115] <![CDATA[r EGRRatioErrAvg ]]> 0 0.01 0.015 <![CDATA[f1(r EGRRatioErrAvg )]]> 0.02 0.01 0

[0116] The purpose of the above adjustment is that if the EGR rate does not fluctuate much when it is near the minimum EGR rate, but the boost pressure fluctuates too much or the torque difference is too large, it is necessary to further slow down the fluctuation of the EGR rate, that is, the filtering time of the EGR rate needs to be lengthened.

[0117] (2)r EGRRatioErrAvg is greater than the preset value, in this example it is 0.05, and the r EGRRatioErrAvg The number of times CNT is greater than the preset value (CNT will be saved after the vehicle is powered off, and its default value is 0). If CNT is greater than the preset value, which is 10 in this example, and the first situation is not met during the increase of CNT, then Among them, f2(r BoostErr )、f2(r TrqErr ) and f2(r EGRRatioErrAvg ) is obtained by calibration:

[0118] <![CDATA[r BoostErr ]]> 0.02 0.05 0.08 0.12 0.15 0.23 <![CDATA[f2(r BoostErr )]]> 1 1.02 1.05 1.06 1.08 1.1

[0119] <![CDATA[r TrqErr ]]> 0.03 0.05 0.08 0.12 0.14 0.16 <![CDATA[f2(r TrqErr )]]> 0.01 0.015 0.02 0.022 0.025 0.03

[0120]

[0121]

[0122] The purpose of the above adjustment is that if the EGR rate fluctuates greatly when it is near the minimum EGR rate, and at the same time the boost fluctuation is too large or the torque deviation is too large, the fluctuation of the EGR rate can be appropriately slowed down to avoid excessive fluctuations in the EGR rate that may affect the engine combustion stability.

[0123] (3) In other cases, r Adapt =r Adapt (z).

[0124] Default situation 2:

[0125] When the following conditions are met:

[0126] The time for the EGR closed-loop enabling state to change from the activated state to the inactivated state does not exceed the preset time. In this embodiment, the preset time is 0.05s, wherein the condition for the EGR closed-loop enabling condition to change to the inactivated state is that the EGR closed-loop enabling minimum EGR rate condition is not satisfied;

[0127] The EGR closed loop enabled state activation time exceeds the preset time, and the preset time in this embodiment is 0.5s;

[0128] The fire circuit torque fluctuation is requested to be within a preset range, which in this embodiment is ±2Nm;

[0129] The target boost pressure fluctuation is within a preset range, which in this embodiment is ±2 kPa;

[0130] The accumulated mileage of the engine whose self-learning coefficient is not updated exceeds a preset value, and in this embodiment, the preset value is 20,000 kilometers.

[0131] After the above conditions are met, read the r value of the EGR closed-loop enable state before it enters the inactive state (0.2s in this example) BoostErr Average value r BoostErrAvg1 and r TrqErr Average value r TrqErrAvg1 , and the time r after the EGR closed-loop enabling state enters the inactive state (0.2s in this example) Boost E rr Average value r BoostErrAvg2 and r Trq E rr Average value r TrqErrAvg2 If it appears:

[0132] (1)r BoostErrAvg1 >k1>r BoostErrAvg2 , and r TrqErrAvg1 >k2>r TrqErrAvg2 , then r A d apt =r Adapt (z)-0.1

[0133] (2)r BoostErrAvg1 <k1<r BoostErrAvg2 , and r TrqErrAvg1 <k2<r TrqErrAvg2 ,but

[0134] r Adapt =r Adapt (z)+0.12

[0135] (3) In other cases, r Adapt =r Adapt (z)

[0136] Among them, r Adapt (z) is the minimum EGR rate filter time self-learning correction coefficient r obtained from the last self-learning update Adapt .

[0137] The self-learning correction coefficient r is used during the current minimum EGR rate filtering time. Adapt After the update, the new coefficient is used to update the minimum EGR rate filter time in the next driving cycle of the vehicle.

[0138] S2. Determine the minimum EGR rate for judging the EGR enabling condition according to the minimum EGR rate original value and the minimum EGR rate filtered value.

[0139] When any special demand condition is met, the EGR rate request needs to be realized as soon as possible, then the minimum EGR rate is equal to the original value of the minimum EGR rate;

[0140] In other cases, in order to better ensure the stability of EGR control, the minimum EGR rate is equal to the minimum EGR rate filter value.

[0141] The special demand conditions are specifically:

[0142] Special demand condition 1:

[0143] The difference between the ignition angle efficiency and the ignition angle efficiency of the previous sampling period is within a preset range or the ignition angle efficiency exceeds a preset value. In this embodiment, the preset range is greater than 0.2 but less than 0.3, and the preset value is 0.95;

[0144] There is no fuel cut-off request from the engine;

[0145] The engine did not experience any knock and pre-ignition;

[0146] The engine fresh air intake density fluctuation does not exceed a preset range, which in this embodiment is ±35 mgpl;

[0147] When the continuous time during which all the above conditions are met simultaneously exceeds the preset time, it indicates that the special demand working condition is met. In this embodiment, the preset time is 0.03s.

[0148] Special demand condition 2:

[0149] The difference between the air-fuel ratio and the air-fuel ratio of the previous sampling period exceeds a preset value, and in this embodiment, the preset value is 1;

[0150] There is no fuel cut-off request from the engine;

[0151] The engine intake temperature exceeds a preset value, which in this embodiment is 50°C;

[0152] The engine water temperature exceeds a preset value, which in this embodiment is 110°C;

[0153] When the continuous time that all the above conditions are met simultaneously exceeds the preset time, it indicates that the special demand working condition 2 is met. In this embodiment, the preset time is 0.1s.

[0154] S3. Determine whether the minimum EGR rate condition for enabling EGR closed loop is met according to the minimum EGR rate.

[0155] The EGR closed loop enabling minimum EGR condition is specifically:

[0156] (1) When the difference between the target EGR rate and the minimum EGR rate is greater than a preset value A, the EGR closed loop enabling minimum EGR rate condition is met. In this example, the preset value A is 0.02.

[0157] (2) When the difference between the target EGR rate and the minimum EGR rate is not greater than the preset value B, and the absolute value of the difference between the target EGR rate and the actual EGR rate is not greater than the preset value C, the EGR closed-loop enabling minimum EGR rate condition is not met. In this example, the preset value B is 0.01 and the preset value C is 0.1.

[0158] (3) In other cases, the EGR closed loop enabling minimum EGR rate condition maintains the previous state. The default state is when the vehicle is powered on, and the default state is that the EGR closed loop enabling minimum EGR rate condition is not met.

[0159] S4. When the EGR closed-loop enabling minimum EGR rate condition is met, whether the EGR closed-loop is enabled is determined according to the EGR closed-loop enabling condition.

[0160] The specific EGR closed loop enabling conditions are:

[0161] There were no malfunctions related to the EGR system parts;

[0162] No fuel cut-off request occurs and the fuel cut-off recovery time exceeds the preset time. In this embodiment, the preset time is 0.3s;

[0163] The minimum EGR rate condition for EGR closed loop is met;

[0164] The engine speed is within a preset speed range, and in this embodiment, the preset speed range is 750 rpm to 5500 rpm;

[0165] The intake air temperature is within the preset range. If the current state is EGR closed loop disabled, the EGR closed loop state is entered, and the minimum intake air temperature must be no less than 10°C. If the current state is EGR closed loop enabled, the EGR system closed loop enabled state must be exited, and the minimum intake air temperature must be 7°C lower. If the current state is EGR closed loop disabled, the EGR closed loop state is entered, and the maximum intake air temperature must be no more than 60°C. If the current state is EGR closed loop enabled, the EGR system closed loop enabled state must be exited, and the maximum intake air temperature must be exceeded by 65°C.

[0166] The engine water temperature is within the preset range. If the current state is EGR closed loop disabled, the engine enters the EGR closed loop state, and the minimum water temperature must be no less than 60°C. If the current state is EGR closed loop enabled, the engine exits the EGR system closed loop enabled state and the minimum water temperature must be 55°C. If the current state is EGR closed loop disabled, the engine enters the EGR closed loop state, and the maximum water temperature must be no more than 115°C. If the current state is EGR closed loop enabled, the engine exits the EGR system closed loop enabled state and the maximum water temperature must be no more than 120°C.

[0167] The atmospheric temperature is within the preset range. If the current state is EGR closed loop disabled, the EGR closed loop state is entered, and the minimum atmospheric temperature must be no less than 5°C. If the current state is EGR closed loop enabled, the EGR system closed loop enabled state must be exited, and the minimum atmospheric temperature must be 3°C lower. If the current state is EGR closed loop disabled, the EGR closed loop state is entered, and the maximum atmospheric temperature must be no more than 55°C. If the current state is EGR closed loop enabled, the EGR system closed loop enabled state must be exited, and the maximum atmospheric temperature must be no more than 60°C.

[0168] The atmospheric pressure exceeds a preset pressure value. In this embodiment, the preset pressure value is 66 kPa. In addition, when the atmospheric pressure is lower than 64 kPa, the EGR closed-loop enabling condition becomes unsatisfied.

[0169] The EGR closed loop is enabled only when the above conditions are met at the same time, otherwise the EGR closed loop is not enabled.

[0170] like Figure 2As shown, the present invention also provides a system structure with EGR, including an air filter 1, a mixing valve 2, a compressor 3, a throttle 4, an engine 5, a turbine 6, a catalyst 7, a particulate matter trap 8, and an EGR cooler 9, an EGR valve 10, a temperature sensor 11 installed between the EGR valve 10 and the EGR cooler 9, and a branch composed of a pressure difference sensor 12 connected to the EGR valve 10; the two ends of the branch are respectively connected to the outlet of the particulate matter trap 8 and the outlet of the mixing valve 2; wherein the mixing valve 2 is used to adjust the pressure at the outlet of the EGR valve 10 and increase the pressure difference at both ends of the EGR valve 10, the engine 5 is used to compress fresh air for supercharging, the turbine 6 is used to control the opening of the exhaust bypass valve, the EGR cooler 9 is used to receive the exhaust gas output by the particulate matter trap 8 and cool it to increase the exhaust gas flow rate, the EGR valve 10 is used to control the exhaust gas flow entering the cylinder, the temperature sensor 11 is used to detect the exhaust gas temperature entering the EGR valve 10, and the pressure difference sensor 12 is used to detect the pressure at the inlet and outlet of the EGR valve 10. The system structure is used to execute an EGR closed-loop exit control method based on boost control responsiveness described in this embodiment.

[0171] The present invention optimizes the minimum EGR rate, optimizes the region where the EGR rate enters the minimum EGR rate, optimizes the EGR enabling condition judgment method, reduces the oscillation probability of the control actuator, improves the EGR system, and improves the stability of the system.

[0172] In addition, the present invention also provides a computer-readable storage medium having a computer program stored thereon. The computer program includes executable instructions. When the executable instructions are executed by a processor, the engine performance improvement control method based on improving aging loss as described above is implemented.

[0173] 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.

[0174] The order of execution of each step in the above embodiment does not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0175] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A control method for improving engine performance based on improving aging loss, characterized in that: The method comprises: Obtaining a minimum EGR rate original value, and obtaining a minimum EGR rate filtered value according to the minimum EGR rate original value; Determining a minimum EGR rate for judging an EGR enabling condition according to a minimum EGR rate original value and a minimum EGR rate filtered value; Determining whether the minimum EGR rate condition for enabling EGR closed loop is met according to the minimum EGR rate; When the minimum EGR rate condition for enabling the EGR closed loop is met, whether the EGR closed loop is enabled is determined according to the EGR closed loop enabling condition.

2. The engine performance improvement control method based on improving aging loss according to claim 1, characterized in that: The minimum EGR rate filtered value is specifically obtained by multiplying the difference between the minimum EGR rate original value and the minimum EGR rate filtered value obtained in the previous sampling period by the sampling period interval, divided by the minimum EGR rate filtering time, and adding the minimum EGR rate filtered value obtained in the previous sampling period.

3. The engine performance improvement control method based on improving aging loss according to claim 2, characterized in that: The minimum EGR rate filtering time is specifically obtained by the following method: When the preset conditions are met, the minimum EGR rate filter time is equal to the sum of the minimum EGR rate filter time self-learning correction coefficient and 1, multiplied by the product of the boost pressure fluctuation correction coefficient and the engine torque fluctuation correction coefficient and the preset filter time; In other cases, the minimum EGR rate filtering time is equal to the preset filtering time.

4. The engine performance improvement control method based on improving aging loss according to claim 3 is characterized in that: The preset conditions are specifically: The engine torque fluctuation correction factor or the boost pressure fluctuation correction factor is not equal to 1.

5. The engine performance improvement control method based on improving aging loss according to claim 3, characterized in that: The boost pressure fluctuation correction coefficient is determined according to the boost pressure difference original value and the boost pressure difference filtered value; If the absolute value of the difference between the boost pressure difference filtered value and the boost pressure difference divided by the minimum value among the boost pressure difference original value, the boost pressure difference filtered value and the preset value is greater than a certain value for a continuous time exceeding the preset time, the boost pressure fluctuation correction coefficient is obtained by calibration, otherwise the boost pressure fluctuation correction coefficient is equal to 1.

6. The engine performance improvement control method based on improving aging loss according to claim 1, characterized in that: The engine torque fluctuation correction coefficient is determined according to the torque difference and the torque difference filter value; the torque difference is the difference between the engine requested fire circuit torque and the actual fire circuit torque; If the absolute value of the difference between the torque difference filter value and the torque difference divided by the minimum value among the torque difference, the torque difference filter value and the preset value is greater than a certain value for a continuous time exceeding the preset time, the engine torque fluctuation correction coefficient is obtained by calibration, otherwise the engine torque fluctuation correction coefficient is equal to 1.

7. The engine performance improvement control method based on improving aging loss according to claim 1, characterized in that: The minimum EGR rate determined for judging the EGR enabling condition is specifically: When any special demand condition is met, the minimum EGR rate is equal to the original value of the minimum EGR rate; In other cases, the minimum EGR rate is equal to the minimum EGR rate filtered value.

8. The engine performance improvement control method based on improving aging loss according to claim 7, characterized in that: The special demand working conditions are specifically: Special demand condition 1: The difference between the ignition angle efficiency and the ignition angle efficiency of the previous sampling period is within a preset range or the ignition angle efficiency exceeds a preset value; There is no fuel cut-off request from the engine; The engine did not experience any knock and pre-ignition; The engine fresh air intake density fluctuation does not exceed the preset range; When all the above conditions are met simultaneously for a continuous time exceeding the preset time, it indicates that the special demand condition is met; Special demand condition 2: The difference between the air-fuel ratio and the air-fuel ratio of the previous sampling period exceeds the preset value; There is no fuel cut-off request from the engine; The engine intake air temperature exceeds the preset value; The engine water temperature exceeds the preset value; When the continuous time that all the above conditions are met simultaneously exceeds the preset time, it indicates that the special demand condition 2 is met.

9. The engine performance improvement control method based on improving aging loss according to claim 1, characterized in that: The specific conditions for determining whether the minimum EGR rate for enabling the EGR closed loop is met according to the minimum EGR rate are: When the difference between the target EGR rate and the minimum EGR rate is greater than a preset value of one, the EGR closed loop enabling minimum EGR rate condition is met; When the difference between the target EGR rate and the minimum EGR rate is not greater than the preset value 2, and the absolute value of the difference between the target EGR rate and the actual EGR rate is not greater than the preset value 3, the EGR closed loop enabling minimum EGR rate condition is not met; In other cases, the EGR closed loop enabling minimum EGR rate condition maintains the previous state, where the vehicle is powered on and is in the default state, in which the EGR closed loop enabling minimum EGR rate condition is not met.

10. The engine performance improvement control method based on improving aging loss according to claim 1, characterized in that: The specific judgment of whether the EGR closed loop is enabled is as follows: There were no malfunctions related to the EGR system parts; No fuel cut request occurs and the fuel cut recovery time exceeds the preset time; The minimum EGR rate condition for EGR closed loop is met; The engine speed is within the preset speed range; The intake air temperature is within the preset range; The engine water temperature is within the preset range; The atmospheric temperature is within the preset range; Atmospheric pressure exceeds the preset pressure value.

11. The engine performance improvement control method based on improving aging loss according to claim 3, characterized in that: The minimum EGR rate filter time self-learning correction coefficient is specifically obtained by the following method: When any of the following conditions is met, the minimum EGR rate filter time self-learning correction coefficient is updated: Case 1: EGR closed loop is enabled, and the EGR closed loop enabling time does not exceed the preset time; The boost pressure fluctuation correction coefficient is greater than a certain value for a continuous period exceeding a preset time; The engine torque fluctuation correction coefficient is greater than a certain value for a continuous period exceeding a preset time; The difference between the target EGR rate and the current minimum EGR rate does not exceed a preset value; The accumulated mileage of the engine whose self-learning coefficient is not updated exceeds the preset value; When all the above conditions are met, it means that situation 1 is met; Case 2: The time from the activated state to the inactivated state of the EGR closed loop enabling state does not exceed the preset time; The EGR closed loop enable state activation time exceeds the preset time; Request the fire circuit torque fluctuation to be within the preset range; The target boost pressure fluctuation is within a preset range; The accumulated mileage of the engine whose self-learning coefficient is not updated exceeds the preset value; When the EGR closed loop enabling minimum EGR rate condition is not met, the EGR closed loop enabling state enters the inactive state; When all the above conditions are met, it means that situation 2 is met.

12. The engine performance improvement control method based on improving aging loss according to claim 11, characterized in that: When the first condition is met, the average value of the absolute value of the ratio of the difference between the target EGR rate and the actual EGR rate within a certain period of time after the EGR closed-loop enable is activated and the target EGR rate is read. If the average value is not greater than the preset value, the updated minimum EGR rate filter time self-learning correction coefficient is equal to the sum of the last updated minimum EGR rate filter time self-learning correction coefficient and the change value; If the average value is greater than the preset value, the number of times the average value is greater than the preset value is recorded; if the number of times the average value is greater than the preset value is greater than the preset number, and in the process of increasing the number, the first condition is not satisfied, then the updated minimum EGR rate filter time self-learning correction coefficient is equal to the difference between the last updated minimum EGR rate filter time self-learning correction coefficient and the change value; In other cases that satisfy condition 1, the updated minimum EGR rate filter time self-learning correction coefficient is equal to the last updated minimum EGR rate filter time self-learning correction coefficient; When the second condition is met, the average value 1 of the boost pressure fluctuation correction coefficient and the average value 1 of the engine torque fluctuation correction coefficient during the activation state time before the EGR closed-loop enabling state enters the inactive state are read, and the average value 2 of the boost pressure fluctuation correction coefficient and the average value 2 of the engine torque fluctuation correction coefficient during the inactive state time after the EGR closed-loop enabling state enters the inactive state are read. If the preset value 1 is greater than the average value 2 of the boost pressure fluctuation correction coefficient and less than the average value 1 of the boost pressure fluctuation correction coefficient, and the preset value 2 is greater than the average value 2 of the engine torque fluctuation correction coefficient and less than the average value 1 of the engine torque fluctuation correction coefficient, then the updated minimum EGR rate filter time self-learning correction coefficient is equal to the last updated minimum EGR rate filter time self-learning correction coefficient minus 0.1; If the preset value one is less than the average value two of the boost pressure fluctuation correction coefficient and greater than the average value one of the boost pressure fluctuation correction coefficient, and the preset value two is less than the average value two of the engine torque fluctuation correction coefficient and greater than the average value one of the engine torque fluctuation correction coefficient, then the updated minimum EGR rate filter time self-learning correction coefficient is equal to the last updated minimum EGR rate filter time self-learning correction coefficient plus 0.12; In other cases where condition 2 is satisfied, the updated minimum EGR rate filter time self-learning correction coefficient is equal to the last updated minimum EGR rate filter time self-learning correction coefficient.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer program includes executable instructions, and when the executable instructions are executed by a processor, the engine performance improvement control method based on improving aging loss described in claims 1-12 is implemented.

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