Dynamic control method for opening degree of mixing valve

Abstract

The invention relates to a dynamic control method for the opening degree of a mixing valve. The method comprises the steps that the opening degree and the change rate of the mixing valve when the mixing valve is in the transition working condition from non-full-opening to full-opening are obtained; determining the speed of accelerating full opening of the mixing valve based on the air inlet responsiveness requirement, and setting the speed as a multiplication correction coefficient I; based on the control stability angle, determining the speed at which the mixing valve slows down and enters the full-open state, and setting the speed as a second multiplication correction coefficient; and according to the first multiplication correction coefficient and the second multiplication correction coefficient, the final mixing valve opening degree change rate in the full-opening process of the mixing valve is determined. Based on the purpose of improving emission and dynamic property, the control precision of an EGR system is balanced, the control precision of an air inlet system is improved, and the opening change rate of the mixing valve is controlled and optimized in the process from non-full opening to full opening of the mixing valve.

Description

Technical Field

[0001] The invention relates to the field of engine control, and more particularly to a method for dynamically controlling the opening of a mixing valve. Background Art

[0002] Exhaust Gas Recirculation (EGR) takes exhaust gas from the exhaust and enters the intake system. Studies have shown that the EGR system has certain advantages in improving emissions, reducing fuel consumption and improving anti-knock capabilities. The control of the mixing valve in the low-pressure EGR system is particularly important as it improves the effect of the EGR rate.

[0003] Chinese patent CN112459910A discloses a method and system for calculating a target EGR rate, which determines a basic target EGR rate according to engine speed and load, but does not consider the control accuracy of the target opening of the mixing valve.

[0004] Chinese patent CN112901361A discloses an EGR mixing valve target opening control method and system, which corrects the mixing valve target opening according to various operating parameters, but does not consider the dynamic closed-loop control of the mixing valve target opening. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for dynamically controlling the opening of a mixing valve, which weighs the dynamics when the mixing valve changes from fully open to partially open, and optimizes the mixing valve opening change rate from the perspectives of control stability and emission improvement.

[0006] The technical solution adopted by the present invention to solve the technical problem is: constructing a mixing valve opening dynamic control method, comprising:

[0007] Obtain the mixing valve opening and change rate when the mixing valve is in a transitional state from non-fully open to fully open;

[0008] Determining the rate at which the mixing valve is accelerated to fully open based on the intake responsiveness requirement, which is set to a multiplication correction factor of one;

[0009] Determining the rate at which the mixing valve is slowed down to full opening based on the control stability angle is set as a multiplication correction factor of two;

[0010] The final mixing valve opening change rate when the mixing valve enters the full opening process is determined according to the multiplication correction coefficient one and the multiplication correction coefficient two.

[0011] According to the above scheme, the multiplication correction coefficient r1=r11×r12, wherein r11 and r12 are both sub-correction coefficients.

[0012] According to the above scheme, the method for determining the sub-correction coefficient r11 is as follows:

[0013] When one of the following conditions is met,

[0014] (1) Throttle full open time ratio Not less than 0.05, and the difference rate of air intake Not less than 0.05;

[0015] (2) The engine speed is not less than 1000 rpm, and the boost pressure difference rate Not less than 0.1;

[0016]

[0017] Otherwise, when the above conditions are not met, r11 = 1;

[0018] In the formula, the throttle full open time ratio t is the continuous time when the throttle enters the fully open state ThrWOT The maximum time of throttle valve fully open is t ThrWOTMax ratio; intake volume difference rate The target fresh air intake density rho entering the cylinder Dsrd The actual fresh air intake density rho Act The difference rho Dsrd -rho Act The fresh air intake density rho of the target cylinder Dsrd ratio; characteristic coefficient The throttle valve fully open time ratio Difference rate with intake volume coefficient of determination is the boost pressure difference rate A coefficient determined by the engine speed n.

[0019] According to the above scheme, the coefficient The calibration method is to adjust the throttle full opening time ratio at different engine speeds and stable boost pressure response accuracy. and intake volume difference rate Perform calibration.

[0020] According to the above scheme, the coefficient The calibration method is to set the target fresh air intake density rho at each fixed engine speed, when the throttle is not fully open, and the target fresh air intake density rho is Dsrd The actual fresh air intake density rho Act Under the premise of small, by adjusting the difference rate of different boost pressure Perform calibration.

[0021] According to the above scheme, the method for determining the sub-correction coefficient r12 is as follows:

[0022] When one of the following conditions is met,

[0023] (1) Target EGR rate r EGRDsrd Not less than 0.15, and the transient rate of intake flow Less than -0.05;

[0024] (2) The engine speed is not less than 1000 rpm, and the EGR rate difference rate Less than ±0.015;

[0025]

[0026] Otherwise, when the above conditions are not met, r12 = 1;

[0027] In the formula, the characteristic coefficient is the target EGR rate r EGRDsrd and the transient rate of intake air flow coefficient of determination EGR rate difference rate Coefficient determined by engine speed n; EGR rate difference r EGRDsrd -r EGRAct is the target EGR rate r EGRDsrd and the actual EGR rate r EGRAct difference.

[0028] According to the above scheme, the multiplication correction coefficient r2=r21×r22×r23×r24, wherein r21, r22, r23 and r24 are all pressure fluctuation correction coefficients.

[0029] According to the above scheme, the method for determining the pressure fluctuation correction coefficient r21 is as follows:

[0030] When one of the following conditions is met,

[0031] (1) Throttle inlet pressure fluctuation rate The time not less than 0.05 exceeds 0.2s;

[0032] (2) Mixing valve outlet pressure fluctuation rate The time not less than 0.05 exceeds 0.5s;

[0033]

[0034] Otherwise, when the above conditions are not met, r21 = 1;

[0035] p preFilter (N) = K pre ×[p pre (N)-p preFilter(N-1)]+p preFilter (N-1)

[0036] In the formula, p pre is the throttle inlet pressure, p pre (N) is the throttle outlet intake pressure at the Nth sampling cycle, p preFilter is the throttle inlet pressure after first-order low-pass filtering, p preFilte ( r N) is the filtered throttle inlet intake pressure in the Nth sampling period, p preFilte ( r N-1) is the filtered throttle inlet intake pressure of the N-1th sampling period, N = 1, 2, 3..., p preFilte ( r 0) is equal to the throttle inlet intake pressure p at the 0th sampling cycle pre (0); Where m is the number of engine cylinders, n is the engine speed, k pre is the throttle inlet intake pressure filter coefficient;

[0037] p aftMixFilter (N) = K aftMix ×[p aftMix (N)-p aftMixFilter (N-1)]+p aftMixFilter (N-1)

[0038] In the formula, p aftMix is the outlet pressure of the mixing valve, p aftMix (N) is the outlet pressure of the mixing valve at the Nth sampling period (the sampling period in this example is 10ms), p aftMixFilter is the outlet pressure of the mixing valve after first-order low-pass filtering, p preFilter (N) is the filtered outlet pressure of the mixing valve in the Nth sampling period, p preFilte ( r N-1) is the outlet pressure of the mixing valve after filtering in the N-1th sampling period, N = 1, 2, 3..., p preFilter (0) is equal to the mixing valve outlet pressure p at the 0th sampling cycle aftMix (0); Where m is the number of engine cylinders, n is the engine speed, k aftMix is the mixing valve outlet pressure filtering coefficient;

[0039] is the throttle inlet pressure fluctuation rate The mixing valve outlet pressure fluctuation rate Determined coefficient.

[0040] According to the above scheme, the method for determining the pressure fluctuation correction coefficient r22 is as follows:

[0041] To meet the mixing valve pressure ratio Less than 0.2, and the mixing valve outlet pressure change rate dp aftMix When it is greater than the preset value, Otherwise r22=1;

[0042] Characteristic coefficient The calibration basis is to ensure that the EGR rate difference rate is While not exceeding the preset value (±0.015), when the engine speed is stable and the engine target boost pressure is stable, the supercharger inlet pressure fluctuation range exceeds ±2kPa for no more than 0.1s.

[0043] According to the above scheme, the method for determining the pressure fluctuation correction coefficient r23 is as follows:

[0044] When one of the following conditions is met,

[0045] (1) Throttle full-close time ratio Not less than 0.05, and the difference rate of air intake Less than -0.05;

[0046] (2) The engine speed is not less than 1000 rpm, and the boost pressure difference rate Less than -0.1;

[0047]

[0048] Otherwise, when the above conditions are not met, r23 = 1;

[0049] In the formula, the throttle full closing time ratio t is the continuous time that the throttle enters the fully closed state ThrMin The maximum time t of throttle valve fully closed ThrMinMax ratio; intake volume difference rate The target fresh air intake density rho entering the cylinder Dsrd The actual fresh air intake density rho Act The difference rho Dsrd -rho Act The fresh air intake density rho of the target cylinder Dsrd ratio; characteristic coefficient The throttle valve fully closed time ratio Difference rate with intake volume coefficient of determination is the boost pressure difference rate ) is a coefficient determined by the engine speed n.

[0050] According to the above scheme, the method for determining the pressure fluctuation correction coefficient r24 is as follows:

[0051] To meet the gas volume entering the cylinder dm Cyl The fluctuation exceeds 20mgpl / 10ms continuously for a period exceeding the preset value, and the air-fuel ratio difference rate The time that the temperature is continuously less than -0.2 exceeds the preset value, and the cylinder inlet temperature T Port When the temperature is greater than 50°C and the target EGR rate does not exceed the preset value,

[0052]

[0053] Otherwise, r24=1;

[0054] In the formula, the cylinder flow fluctuation rate is is the fresh air intake flow rate dm entering the cylinder during the current sampling period Cyl Compared with the fresh air intake flow rate dm entering the cylinder in the previous sampling cycle Cyl (z)dm Cyl -dm Cyl (z) and the fresh air intake flow rate dm entering the cylinder during the current sampling period Cyl ratio; air-fuel ratio difference rate is the target air-fuel ratio r AFRDsrd The actual air-fuel ratio AFRAct The difference AFRDsrd -r AFRAct and the target air-fuel ratio r AFRDsrd The ratio of is the cylinder flow fluctuation rate Difference rate of air-fuel ratio coefficient of determination Air-fuel ratio difference and cylinder inlet temperature T Port Determined coefficient.

[0055] According to the above scheme, in the method of determining the final mixing valve opening change rate during the mixing valve entering the fully open process according to the multiplication correction coefficient 1 and the multiplication correction coefficient 2,

[0056] If the multiplication correction coefficient is greater than 1, it indicates that the preliminary mixing valve enters the fully open state in advance;

[0057] If the multiplication correction factor 1 is not greater than 1, and the multiplication correction factor 2 is less than 1, it is characterized that the preliminary mixing valve is delayed in entering the fully open state;

[0058] If the above two conditions are not met, it indicates that the preliminary mixing valve enters the normal control state.

[0059] According to the above scheme, in the method of determining the final mixing valve opening change rate during the mixing valve entering the fully open process according to the multiplication correction coefficient 1 and the multiplication correction coefficient 2,

[0060] When the final mixing valve state is the mixing valve fully open state under normal control, dpct MGVNew =dpct MGVRaw ;

[0061] The final mixing valve state is when the mixing valve enters the fully open state in advance, dpct MGVNew =dpct MGVRaw ×r1;

[0062] The final mixing valve state is that the mixing valve is delayed to enter the fully open state, dpct MGVNew =dpct MGVRaw ×r2;

[0063] Where, dpct MGVNew is the final mixing valve opening change rate, dpct MGVRaw is the rate of change of the mixing valve opening when the mixing valve is in a transitional condition from non-fully open to fully open, r1 is the multiplication correction coefficient one, and r2 is the multiplication correction coefficient two.

[0064] The present invention also provides an electronic device, comprising: a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; a computer program is stored in the memory, and when the program is executed by the processor, the processor executes the steps of the mixing valve opening dynamic control method.

[0065] The implementation of the mixing valve opening dynamic control method of the present invention has the following beneficial effects:

[0066] The present invention aims to improve emission and power, balances the control accuracy of the EGR system and improves the control accuracy of the intake system, and optimizes the control of the mixing valve opening rate during the process from the mixing valve being partially open to being fully open. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0068] Figure 1 It is a schematic diagram of the low-pressure EGR system architecture;

[0069] Figure 2 is a flow chart of a method for dynamically controlling the opening degree of a mixing valve according to the present invention;

[0070] Figure 3 It is a logic block diagram of the dynamic control method of the mixing valve opening of the present invention;

[0071] 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

[0072] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0073] Embodiment 1

[0074] like Figure 1 As shown, the low-pressure EGR system includes an air filter, a mixing valve, a supercharger compressor, a throttle, an engine, a supercharger turbine, a catalyst, a particulate matter trap, an EGR cooler, an EGR valve, an EGR temperature sensor, and an EGR differential pressure sensor.

[0075] The supercharger compressor compresses fresh air for supercharging; the supercharger turbine controls the working efficiency of the turbine by controlling the opening of the supercharger's exhaust bypass valve, thereby achieving different supercharging capabilities; the low-pressure EGR system has the following additional components compared to the non-low-pressure EGR system: EGR cooler, EGR temperature sensor, EGR valve, EGR pressure difference sensor, and mixing valve; the mixing valve is used to adjust the pressure at the outlet of the EGR valve, increase the pressure difference at both ends of the EGR valve, and increase the EGR rate; the EGR cooler is used to cool the exhaust gas to increase the exhaust gas flow rate and reduce the exhaust gas temperature; the EGR valve has a throttling effect to control the exhaust gas flow entering the cylinder; the EGR temperature sensor is used to detect the exhaust gas temperature entering the EGR valve; the EGR pressure difference sensor is used to detect the pressure at the EGR inlet and outlet.

[0076] The present invention proposes a method for dynamic control of the mixing valve opening to solve the problems of control stability, power and engine safety protection in the process. Patent CN202110184826.8 "Method for determining the target opening of the mixing valve in the EGR system" and patent CN202110184815.X "Method for determining the activation state of the mixing valve in the low-pressure EGR system" both mention transition control in the process of the mixing valve from non-fully open (activated state) to fully open (activated), and determine the transition change of the target opening of the mixing valve. This patent optimizes the change rate of the target opening of the mixing valve when the mixing valve requests to enter the full opening process, so as to further improve the control stability, power and engine safety protection in the control process.

[0077] like Figure 2-3 As shown, the mixing valve opening dynamic control method of the present invention comprises the following steps:

[0078] S1. Based on the current public technology, the current mixing valve is in a transitional state from non-fully open to fully open, and the current mixing valve opening is pct MGVRaw , and the rate of change is dpct MGVRaw .

[0079] S2. Based on the intake responsiveness requirement, determine the speed at which the mixing valve accelerates to full opening, and set it as a multiplication correction coefficient - r1, where the coefficient - r1 is not less than 1. The multiplication correction coefficient - r1 consists of two parts, namely r1 = r11 × r12. The intake responsiveness requirement directly affects the dynamic responsiveness.

[0080] S201, the method for determining the sub-correction coefficient r11 is as follows:

[0081] When one of the following conditions is met,

[0082] (A) Throttle full open time ratio Not less than 0.05, and the difference rate of air intake Not less than 0.05;

[0083] (B) The engine speed is not less than 1000 rpm, and the boost pressure difference rate Not less than 0.1;

[0084]

[0085] Otherwise, when the above conditions are not met, r11=1.

[0086] If the above conditions are met, the next step describes the detailed method of obtaining r11:

[0087] i) Throttle full open time ratio t is the continuous time when the throttle enters the fully open state ThrWOT The maximum time of throttle valve fully open is t ThrWOTMax (calibrated as 0.8s in this example), that is, when the throttle valve enters the fully open state for a continuous time exceeding the maximum fully open time, the mixing valve opening change rate is adjusted to remain unchanged; the intake volume difference rate The target fresh air intake density rho entering the cylinder Dsrd The actual fresh air intake density rho Act The difference rho Dsrd -rho Act The fresh air intake density rho of the target cylinder Dsrd Ratio.

[0088] Characteristic coefficient The throttle valve fully open time ratio Difference rate with intake volume Determine the coefficient. The larger the value is, the longer the throttle valve needs to be fully open, indicating that the power torque demand is large, and the characteristic coefficient The larger the value, the faster the mixing valve will be fully opened, the throttling loss of the mixing valve will be improved, and the power torque demand will be responded to; When the larger the gas volume response, the lower the dynamic response, the greater the characteristic coefficient. The larger the value, the faster the mixing valve enters full opening, improves the mixing valve throttling loss, and responds to power torque requirements.

[0089] That The calibration method is to adjust the throttle full opening time ratio at different engine speeds n under the premise of stable boost pressure response accuracy (the difference between the target boost pressure and the actual boost pressure is within ±2kPa). and intake volume difference rate Calibration is performed based on ensuring that the difference between the engine target torque and the actual torque is controlled within ±5Nm for no more than 0.5s during the transition from the mixing valve being partially open to being fully open.

[0090] The minimum adjustment coefficient is 1 and the maximum is 1.3. Avoid excessive adjustment that causes the difference between the target EGR rate and the actual EGR rate to exceed the preset value (±0.12 in this example).

[0091] In order to avoid the difference in intake volume Too frequent fluctuations lead to If the adjustment change is too large and the correction coefficient r11 changes too much, resulting in excessive fluctuations in the mixing valve opening control and poor mixing valve control stability, the following treatment should be performed:

[0092] Intake volume difference Fluctuation (difference rate of intake volume during this sampling period) Compared with the last sampling period When the sampling period (10ms in this example) does not exceed the preset value (±0.1 in this example), the correction coefficient Not updated.

[0093] ii) Characteristic coefficient is the boost pressure difference rate (Boost pressure difference p BoostDsrd -p BoostAct and target boost pressure p BoostDsrd The ratio of the boost pressure difference is the target boost pressure p BoostDsrd and the actual boost pressure p BoostAct The difference between the boost pressure and the engine speed n determines the coefficient. The larger the value, the worse the boost pressure response. In order to improve the boost pressure response capability, the characteristic coefficient The larger the speed, the faster the mixing valve opens, the better the mixing valve throttling loss, the higher the boost inlet pressure, and the faster the response to the boost pressure response demand; at a lower speed n, the same boost pressure difference rate The boost response capability is poor at low speeds. Based on this, the characteristic coefficient Also bigger.

[0094] That The calibration method is to set the target fresh air intake density rho at each fixed engine speed n, with the throttle valve not fully open, and the target fresh air intake density rho Dsrd The actual fresh air intake density rho Act Under the premise of small (difference between target gas volume and actual gas volume within ±20mgpl), by adjusting the difference rate of different boost pressures Calibration is carried out, and the basis for calibration is to ensure that the difference between the target boost pressure and the actual boost pressure exceeds ±2kPa for no more than 0.3s continuously.

[0095] The minimum adjustment coefficient is 1, and the maximum value is greater than the characteristic coefficient The maximum value of is small, and in this example it is 1.15. The purpose is to make the intake air volume responsiveness control priority higher than the boost pressure control priority. The poor boost pressure responsiveness can be adjusted by the boost actuator, and the boost pressure does not directly affect the intake air volume entering the cylinder like the intake air volume, so it will not directly affect the power. And if If the control is too large, it will affect the EGR rate response accuracy, so the setting is made based on this.

[0096] In order to avoid the engine speed n and Too frequent fluctuations lead to If the adjustment change is too large and the correction coefficient r11 changes too much, the mixing valve opening control fluctuates too much, resulting in poor mixing valve control stability, thus affecting the response accuracy of the EGR rate, the following treatment is performed:

[0097] The engine speed fluctuation n (the difference between the engine speed in this sampling period and the engine speed in the previous sampling period, the sampling period in this example is 10ms) does not exceed the preset value (in this example, ±40rpm) and Fluctuation (under this sampling period Compared with the last sampling period When the sampling period (10ms in this example) does not exceed the preset value (±0.12 in this example), the correction coefficient Not updated.

[0098] S202, the method for determining the sub-correction coefficient r12 is as follows:

[0099] When one of the following conditions is met,

[0100] (A) Target EGR rate r EGRDsrd Not less than 0.15, and the transient rate of intake flow Less than -0.05;

[0101] (B) The engine speed is not less than 1000 rpm, and the EGR rate difference rate Less than ±0.015;

[0102]

[0103] Otherwise, when the above conditions are not met, r12=1.

[0104] If the above conditions are met, the next step describes the detailed method of obtaining r12:

[0105] i) Characteristic coefficient is the target EGR rate r EGRDsrd and the transient rate of intake air flow Determine the coefficient. At the target EGR rate r EGRDsrd The smaller the mixing valve is, the faster it opens. The larger the value, the faster the mixing valve opens, and the throttling loss of the mixing valve is improved; in the transient rate of intake flow The smaller the value, the greater the transient response of the gas flow. In order to respond to the power acceleration demand in time, the characteristic coefficient The larger the value, the faster the mixing valve enters full opening, improves the throttling loss of the mixing valve, and responds to the power torque demand;

[0106] That The calibration method is to adjust the target EGR rate r at different engine speeds n under the premise that the EGR rate response accuracy is good (the difference between the target EGR rate and the actual EGR rate is within ±0.1). EGRDsrd and the intake air flow transient rate Calibration is performed based on ensuring that the difference between the engine target torque and the actual torque is controlled within ±5Nm for no more than 0.5s during the transition from the mixing valve being partially open to being fully open.

[0107] The minimum adjustment coefficient is 1 and the maximum is 1.35. Avoid excessive adjustment, which may cause the difference between the target opening of the mixing valve and the actual opening of the mixing valve to exceed the preset value (±1% in this example).

[0108] In order to avoid the target EGR rate r EGRDsrd Fluctuation or transient rate of intake air flow Too frequent fluctuations lead to If the adjustment change is too large and the correction coefficient r12 changes too much, resulting in excessive fluctuations in the mixing valve opening control and poor mixing valve control stability, the following treatment should be performed:

[0109] At the target EGR rate r EGRDsrd Fluctuation (target EGR rate r in this sampling period) EGRDsrd The target EGR rate r in the previous sampling cycle EGRDsrd The sampling period is 10ms in this example) does not exceed the preset value (±0.1 in this example), and the intake flow transient rate Fluctuation (intake flow transient rate during this sampling period Compared with the transient rate of intake flow in the previous sampling period When the sampling period (10ms in this example) does not exceed the preset value (±0.1 in this example), Not updated.

[0110] ii) Characteristic coefficient EGR rate difference rate (EGR rate difference r EGRDsrd -r EGRAct and target boost pressure r EGRDsrd The ratio of EGR rate difference r EGRDsrd -r EGRAct is the target EGR rate r EGRDsrd and the actual EGR rate r EGRAct The difference between the EGR rate and the engine speed n determines the coefficient. The smaller it is, the better the EGR rate responsiveness is. The larger the value, the faster the mixing valve will be fully opened, the throttling loss of the mixing valve will be improved, the engine charging capacity will be improved, and the engine charging efficiency will be improved; according to different engine speeds n, the same EGR rate difference rate is set From the perspective of improving the throttling loss of the mixing valve and the engine charging efficiency, the characteristic coefficient is determined to achieve the best charging efficiency.

[0111] That The calibration method is to fix the target EGR rate r at each engine speed n. EGRDsrd Stable (target EGR rate fluctuation within ±0.05) and intake air flow transient rate Under the premise of stability (its fluctuation range is ±0.03), different EGR rate differences can be achieved by adjusting the EGR valve. Calibration is performed based on ensuring that the engine fuel consumption point is at the lowest level.

[0112] In order to avoid the difference between engine speed n and EGR rate Too frequent fluctuations lead to If the adjustment change is too large and the correction coefficient r11 changes too much, the mixing valve opening control fluctuates too much, resulting in poor mixing valve control stability, thus affecting the response accuracy of the EGR rate, the following treatment is performed:

[0113] The engine speed fluctuation n (the difference between the engine speed in this sampling period and the engine speed in the previous sampling period, the sampling period in this example is 10ms) does not exceed the preset value (in this example, ±40rpm) and the EGR rate difference rate Fluctuation (under this sampling period Compared with the last sampling period When the sampling period (in this example, 10ms) does not exceed the preset value (in this example, ±0.015), the correction coefficient Not updated.

[0114] S3. Determine the rate at which the mixing valve slows down to full opening based on the control stability angle, and set it as the multiplication correction coefficient r2, where the coefficient r2 is not greater than 1. r2 = r21 × r22 × r23 × r24, where r21, r22, r23 and r24 are all pressure fluctuation correction coefficients.

[0115] S301. The method for determining the pressure fluctuation correction coefficient r21 is as follows:

[0116] When one of the following conditions is met,

[0117] (A) Throttle inlet pressure fluctuation rate The time not less than 0.05 exceeds 0.2s;

[0118] (B) Mixing valve outlet pressure fluctuation rate The time not less than 0.05 exceeds 0.5s;

[0119]

[0120] It should be noted that

[0121] p preFilter (N) = K pre ×[p pre (N)-p preFilter (N-1)]+p preFilter (N-1)

[0122] Among them, p pre is the throttle inlet pressure, p pre (N) is the throttle outlet intake pressure at the Nth sampling period (the sampling period in this example is 10ms), p preFilteris the throttle inlet pressure after first-order low-pass filtering, p preFilte ( r N) is the filtered throttle inlet intake pressure in the Nth sampling period, p preFilte ( r N-1) is the filtered throttle inlet intake pressure of the N-1th sampling period, N = 1, 2, 3..., p preFilte ( r 0) is equal to the throttle inlet intake pressure p at the 0th sampling cycle pre (0); The sampling period interval Δt in this example is 10ms. pre is the coefficient: The number of engine cylinders in this example is 4, k pre The calibrated speed is 1000rpm. The purpose of this setting is to normalize the process. Under different cylinder numbers and speeds, no special calibration is required. Only the 4-cylinder engine and the speed of 1000rpm k pre , thereby reducing the calibration test work. Where m is the number of engine cylinders, n is the engine speed, k pre is the throttle inlet intake pressure filter coefficient, which is 0.1 in this example.

[0123] p aftMixFilter (N) = K aftMix ×[p aftMix (N)-p aftMixFilter (N-1)]+p aftMixFilter (N-1)

[0124] Among them, p aftMix is the outlet pressure of the mixing valve, p aftMix (N) is the outlet pressure of the mixing valve at the Nth sampling period (the sampling period in this example is 10ms), p aftMixFilter is the outlet pressure of the mixing valve after first-order low-pass filtering, p preFilter (N) is the filtered outlet pressure of the mixing valve in the Nth sampling period, p preFilter (N-1) is the outlet pressure of the mixing valve after filtering in the N-1th sampling period, N = 1, 2, 3..., p preFilter (0) is equal to the mixing valve outlet pressure p at the 0th sampling cycle aftMix (0); The sampling period interval Δt in this example is 10ms. K aftMix is the coefficient: (The number of engine cylinders in this example is 4, k aftMix The calibrated speed is 1000rpm. The purpose of this setting is to normalize the process. Under different cylinder numbers and speeds, no special calibration is required. Only the 4-cylinder engine and the speed of 1000rpm k aftMix, thereby reducing the calibration test work), where m is the number of engine cylinders, n is the engine speed, k aftMix is the mixing valve outlet pressure filter coefficient, which is 0.1 in this example.

[0125] Otherwise, when the above conditions are not met, r21=1.

[0126] If the above conditions are met, the next step describes the detailed method of obtaining r21:

[0127] is the throttle inlet pressure fluctuation rate The mixing valve outlet pressure fluctuation rate Determine the coefficient of pressure fluctuation rate at the throttle inlet The larger the characteristic coefficient is, the The smaller the pressure, the slower the mixing valve will open, avoiding excessive fluctuations in the mixing valve opening and further deterioration of the throttle inlet pressure fluctuations. The larger the characteristic coefficient is, the The smaller it is, the slower the pressure will enter the mixing valve and fully open, avoiding excessive fluctuations in the mixing valve opening and further deterioration of the mixing valve outlet pressure fluctuations;

[0128] That The calibration basis is to ensure that the EGR rate difference rate during the transition from the mixing valve being partially open to being fully open is The throttle inlet pressure fluctuation rate does not exceed the preset value (±0.015) The time is not less than 0.08 and exceeds 0.2s and the mixing valve outlet pressure fluctuation rate The time not less than 0.08 exceeds 0.5s;

[0129] In order to avoid throttle inlet pressure fluctuation rate and mixing valve outlet pressure fluctuation rate Too frequent fluctuations lead to If the adjustment change is too large and the correction coefficient r21 changes too much, resulting in excessive fluctuations in the mixing valve opening control and poor mixing valve control stability, the following treatment should be performed:

[0130] Throttle inlet pressure fluctuation rate Fluctuation (the difference between the throttle inlet pressure fluctuation rate in this sampling period and the throttle inlet pressure fluctuation rate in the previous sampling period, the sampling period in this example is 10ms) does not exceed the preset value (in this example, ±0.02), and the mixing valve outlet pressure fluctuation rate When the fluctuation (the difference between the mixing valve outlet pressure fluctuation rate in this sampling period and the mixing valve outlet pressure fluctuation rate in the previous sampling period, the sampling period in this example is 10ms) does not exceed the preset value (in this example, ±0.02), the correction coefficient Not updated.

[0131] S302, the method for determining the pressure difference correction coefficient r22 is as follows:

[0132] When the following conditions are met, the mixing valve pressure ratio (mixing valve outlet pressure p aftMix and mixing valve inlet pressure p bfMix The ratio of the mixing valve outlet pressure is less than 0.2, and the mixing valve outlet pressure change rate dp aftMix Greater than the preset value, in this example, 15kPa / 10ms;

[0133]

[0134] Otherwise, when the above conditions are not met, r22=1.

[0135] If the above conditions are met, the next step describes the detailed method of obtaining r21:

[0136] Pressure ratio at mixing valve The smaller the pressure is (indicating that the difference between the inlet and outlet pressures of the mixing valve is too large), and the mixing valve outlet pressure change rate dp aftMix The larger the characteristic coefficient is, the The smaller it is, the slower the mixing valve is fully opened. The closed-loop mixing valve opening changes too much, resulting in a large change in the mixing valve outlet pressure, which causes a sudden increase in the mixing valve pressure and a sudden increase in the boost pressure inlet, resulting in poor boost control stability and robustness.

[0137] That The calibration basis is to ensure that the EGR rate difference rate during the transition from the mixing valve being partially open to being fully open is While not exceeding the preset value (±0.015), when the engine speed is stable and the engine target boost pressure is stable, the time for the supercharger inlet pressure fluctuation range to exceed ±2kPa shall not exceed 0.1s;

[0138] To avoid mixing valve pressure ratio and the mixing valve outlet pressure change rate dp aftMix Too frequent fluctuations lead to If the adjustment change is too large and the correction coefficient r22 changes too much, resulting in excessive fluctuations in the mixing valve opening control and poor mixing valve control stability, the following treatment should be performed:

[0139] Pressure ratio at mixing valve Fluctuation (mixing valve pressure ratio during this sampling period Mixing valve pressure ratio compared to the previous sampling cycle The difference between the sampling period and the sampling period in this example is 10ms) does not exceed the preset value (in this example, ±0.05), and the mixing valve outlet pressure change rate dpaftMix Fluctuation (mixing valve outlet pressure change rate dp in this sampling period) aftMix The mixing valve outlet pressure change rate dp compared with the previous sampling cycle aftMix When the difference between the sampling period and the sampling period in this example is 10ms) does not exceed the preset value (in this example, ±3kPa / 10ms), the correction coefficient Not updated.

[0140] S303, the method for determining the power reduction sub-correction coefficient r23 is as follows:

[0141] When one of the following conditions is met,

[0142] (A) Throttle fully closed (i.e., the throttle opening is minimum here to quickly reduce the gas volume) time ratio Not less than 0.05, and the difference rate of air intake Less than -0.05;

[0143] (B) The engine speed is not less than 1000 rpm, and the boost pressure difference rate Less than -0.1.

[0144]

[0145] Otherwise, when the above conditions are not met, r23=1.

[0146] If the above conditions are met, the next step describes the detailed method of obtaining r23:

[0147] i) Throttle full closing time ratio t is the continuous time that the throttle enters the fully closed state ThrMin The maximum time t of throttle valve fully closed ThrMinMax The ratio (calibrated as 0.8s in this example) means that when the throttle valve enters the fully closed state for a continuous time exceeding the maximum fully closed time, the mixing valve opening change rate is adjusted to remain unchanged; the intake volume difference rate The target fresh air intake density rho entering the cylinder Dsrd The actual fresh air intake density rho Act The difference rho Dsrd -rho Act The fresh air intake density rho of the target cylinder Dsrd Ratio.

[0148] Characteristic coefficient The throttle valve fully closed time ratio Difference rate with intake volume Determine the coefficient. The larger the value is, the longer the time required for the throttle to be fully closed is, indicating that the power torque demand is small, and the characteristic coefficient The smaller the air intake, the slower the mixing valve opens, so as to avoid excessive opening of the mixing valve, which increases the air intake capacity and makes it impossible to reduce the air volume quickly. The smaller the value, the greater the overshoot capability of the gas volume response. The smaller it is, the slower the mixing valve will be fully opened, so as to avoid the mixing valve opening being too large, which will increase the air intake and charging capacity and fail to reduce the air volume quickly;

[0149] That The calibration method is to adjust the throttle full closing time ratio at different engine speeds n under the premise of stable boost pressure response accuracy (the difference between the target boost pressure and the actual boost pressure is within ±2kPa). and intake volume difference rate Calibration is performed based on ensuring that the difference between the engine target torque and the actual torque is controlled within ±5Nm for no more than 0.5s during the transition from the mixing valve being partially open to being fully open.

[0150] The maximum value of the adjustment coefficient is 1, and the minimum value is 0.85. Avoid excessive adjustment that causes the difference between the target EGR rate and the actual EGR rate to exceed the preset value (±0.12 in this example).

[0151] In order to avoid the difference in intake volume Too frequent fluctuations lead to If the adjustment change is too large and the correction coefficient r23 changes too much, resulting in excessive fluctuations in the mixing valve opening control and poor mixing valve control stability, the following treatment should be performed:

[0152] Intake volume difference Fluctuation (difference rate of intake volume during this sampling period) Compared with the last sampling period When the sampling period (10ms in this example) does not exceed the preset value (±0.1 in this example), the correction coefficient Not updated.

[0153] ii) Characteristic coefficient is the boost pressure difference rate (Boost pressure difference p BoostDsrd -p BoostAct and target boost pressure p BoostDsrd The ratio of the boost pressure difference is the target boost pressure p BoostDsrd and the actual boost pressure p BoostAct The difference between the boost pressure and the engine speed n determines the coefficient. The smaller the boost pressure response is, the greater the overshoot is. In order to reduce the overshoot of boost pressure, the characteristic coefficient The smaller the speed, the slower the mixing valve is fully opened, so as to avoid the mixing valve opening being too large and thus increasing the supercharger inlet pressure and failing to improve the supercharger pressure overshoot phenomenon; the larger the speed n, the same boost pressure difference rate The higher the boost response capability at high speed, the higher the characteristic coefficient Also smaller.

[0154] That The calibration method is to set the target fresh air intake density rho at each fixed engine speed n, with the throttle valve not fully open, and the target fresh air intake density rho Dsrd The actual fresh air intake density rho Act Under the premise of small (difference between target gas volume and actual gas volume within ±20mgpl), by adjusting the difference rate of different boost pressures Calibration is carried out based on ensuring that the difference between the target boost pressure and the actual boost pressure exceeds ±2kPa for no more than 0.3s continuously.

[0155] The maximum value of the adjustment coefficient is 1, and the minimum value is smaller than the characteristic coefficient The minimum value is large, and in this example it is 0.92. The purpose is to make the intake air volume responsiveness control priority higher than the boost pressure control priority. The poor boost pressure responsiveness can be adjusted by the boost actuator, and the boost pressure does not directly affect the intake air volume entering the cylinder like the intake air volume, so it will not directly affect the power. And if If the control is too large, it will affect the EGR rate response accuracy, so the setting is made based on this.

[0156] In order to avoid the engine speed n and Too frequent fluctuations lead to If the adjustment change is too large and the correction coefficient r23 changes too much, the mixing valve opening control fluctuates too much, resulting in poor mixing valve control stability, thus affecting the response accuracy of the EGR rate, the following treatment is performed:

[0157] The engine speed fluctuation n (the difference between the engine speed in this sampling period and the engine speed in the previous sampling period, the sampling period in this example is 10ms) does not exceed the preset value (in this example, ±40rpm) and Fluctuation (under this sampling period Compared with the last sampling period When the sampling period (10ms in this example) does not exceed the preset value (±0.12 in this example), the correction coefficient Not updated.

[0158] S304, the method for determining the emission sub-correction coefficient r24 is as follows:

[0159] When the following conditions are met,

[0160] Gas volume entering the cylinder dm Cyl Fluctuation (the amount of gas entering the cylinder during this sampling period, dm Cyl Compared with the gas volume entering the cylinder in the previous sampling cycle dm Cyl The difference between the sampling period and the air-fuel ratio difference rate is 10 ms in this example. The time that the difference exceeds 20 mgpl / 10 ms continuously exceeds the preset value (0.5 s in this example). The time that the continuous value is less than -0.2 exceeds the preset value (0.5s in this example), and the cylinder inlet temperature T Port Greater than 50°C, and the target EGR rate does not exceed the preset value (0.1 in this example);

[0161]

[0162] Otherwise, when the above conditions are not met, r24=1.

[0163] If the above conditions are met, the next step describes the detailed method of obtaining r24:

[0164] i) Cylinder flow rate fluctuation rate is the fresh air intake flow rate dm entering the cylinder during the current sampling period Cyl Compared with the fresh air intake flow rate dm entering the cylinder in the previous sampling cycle Cyl (z)dm Cyl -dm Cyl (z) and the fresh air intake flow rate dm entering the cylinder during the current sampling period Cyl Air-fuel ratio difference is the target air-fuel ratio r AFRDsrd The actual air-fuel ratio AFRAct The difference AFRDsrd -r AFRAct and the target air-fuel ratio r AFRDsrd ratio.

[0165] Characteristic coefficient is the cylinder flow fluctuation rate Difference rate of air-fuel ratio Determine the coefficient of fluctuation of the flow rate in the cylinder The larger the air-fuel ratio difference The smaller it is, the greater the increase in intake air flow and the leaner the air-fuel ratio, the smaller the characteristic coefficient The smaller it is, the slower the mixing valve is fully opened, which prevents the EGR exhaust gas flow from entering the cylinder, which can easily cause an increase in NOx emissions;

[0166] That The calibration method is to use the cylinder inlet temperature T PortUnder the premise of not exceeding the preset value (55℃ in this example), the flow fluctuation rate of different cylinders is adjusted. Difference rate of air-fuel ratio Calibration is performed based on ensuring the lowest NOx emissions during the transition from the mixing valve being partially open to being fully open.

[0167] The maximum value of the adjustment coefficient is 1, and the minimum value is 0.92. Avoid excessive adjustment that causes the difference between the target EGR rate and the actual EGR rate to exceed the preset value (±0.12 in this example).

[0168] To avoid cylinder flow fluctuations and air-fuel ratio difference Too frequent fluctuations lead to If the adjustment change is too large and the correction coefficient r24 changes too much, resulting in excessive fluctuations in the mixing valve opening control and poor mixing valve control stability, the following treatment should be performed:

[0169] Fluctuation rate of flow in cylinder Fluctuation (difference rate of intake volume in this sampling period, fluctuation rate of cylinder flow rate Cylinder flow fluctuation rate compared with the previous sampling period The difference between the sampling period and the air-fuel ratio difference rate is 10ms in this example. Fluctuation (difference rate of air-fuel ratio in this sampling period) The difference between the air-fuel ratio and the last sampling period When the difference (the sampling period in this example is 10ms) does not exceed the preset value (in this example ±0.1), the correction coefficient Not updated.

[0170] ii) Characteristic coefficient Air-fuel ratio difference and cylinder inlet temperature T Port Determine the coefficient. The smaller the cylinder inlet temperature T Port The higher the value, the leaner the air-fuel ratio and the higher the intake temperature. The smaller it is, the slower the mixing valve opens, avoiding the EGR exhaust gas flow into the cylinder, which easily causes an increase in NOx emissions.

[0171] That The calibration method is to take the gas volume dm entering the cylinder Cyl Fluctuation (the amount of gas entering the cylinder during this sampling period, dm Cyl Compared with the gas volume entering the cylinder in the previous sampling cycle dm CylThe difference between the two (the sampling period in this example is 10ms) does not exceed 20mgpl / 10ms, and the air-fuel ratio difference rate is fixed. Under this premise, by adjusting the cylinder inlet temperature T Port Calibration is performed based on ensuring the lowest NOx emissions during the transition from partially open to fully open mixing valve.

[0172] The maximum value of the adjustment coefficient is 1, and the minimum value is 0.5. Avoid excessive adjustment that causes the difference between the target EGR rate and the actual EGR rate to exceed the preset value (±0.12 in this example).

[0173] In order to avoid the cylinder intake temperature T Port and air-fuel ratio difference Too frequent fluctuations lead to If the adjustment change is too large and the correction coefficient r24 changes too much, resulting in excessive fluctuations in the mixing valve opening control and poor mixing valve control stability, the following treatment should be performed:

[0174] At the cylinder inlet temperature T Port Fluctuation (the cylinder inlet temperature T in this sampling period) Port Compared with the cylinder inlet temperature T in the previous sampling cycle Port The difference between the sampling period and the air-fuel ratio difference rate is 10ms in this example. Fluctuation (difference rate of air-fuel ratio in this sampling period) The difference between the air-fuel ratio and the last sampling period When the difference (the sampling period in this example is 10ms) does not exceed the preset value (in this example ±0.1), the correction coefficient Not updated.

[0175] S4. Determine the final mixing valve opening change rate when the mixing valve enters the full opening process according to the multiplication correction coefficient 1 and the multiplication correction coefficient 2.

[0176] First, judge.

[0177] 1) If r1 is greater than 1, it indicates that the preliminary mixing valve enters the fully open state in advance;

[0178] 2) If the first condition is not satisfied, if r2 is less than 1, it is characterized by a delay in the preliminary mixing valve entering the fully open state;

[0179] 3) If the above two conditions are not met, it indicates that the preliminary mixing valve enters the normal control state.

[0180] The checking period for each state is 10ms in this example.

[0181] If the preliminary mixing valve is fully open in advance, and r 11 >1, the preliminary mixing valve enters the fully open state in advance; otherwise, the preliminary mixing valve enters the fully open state in advance;

[0182] If the preliminary mixing valve is currently delayed from entering the fully open state, and r 24 <1, the preliminary mixing valve is delayed to enter the fully open state; otherwise, judge again, if r 23 <1 means the preliminary mixing valve enters the fully open state in advance; otherwise, judge again if r 22 <1 means that the preliminary mixing valve enters the fully open state 2 in advance; otherwise, the preliminary mixing valve enters the fully open state 1 in advance.

[0183] If the previous state is that the preliminary mixing valve enters the normal control state, and the current state is that the preliminary mixing valve enters the fully open state in advance, then the final mixing valve state is that the mixing valve enters the fully open state in advance;

[0184] Similarly, if the previous state is that the preliminary mixing valve enters the normal control state, and the current state is that the preliminary mixing valve delays entering the fully open state, then the final mixing valve state is that the mixing valve delays entering the fully open state;

[0185] If the previous state is that the preliminary mixing valve enters the fully open state in advance, and the current state is that the preliminary mixing valve delays entering the fully open state, then the final mixing valve state first enters the normal control state of the mixing valve and maintains it for a period of time t0, and then it is divided into the following situations:

[0186] A) If the initial mixing valve delay entering the fully open state changes before the end of time t0 (i.e., for example, the initial mixing valve delay entering the fully open state 1 is adjusted to the initial mixing valve delay entering the fully open state 2), the final mixing valve state is immediately changed to the mixing valve delay entering the fully open state.

[0187] B) If the delay in the initial mixing valve entering the fully open state does not change before the end of time t0, or if the initial mixing valve enters the fully open state ahead of schedule again, the final mixing valve state will still be the normal control state of the mixing valve.

[0188] C) If after the t0 time is over, the final mixing valve state is immediately updated to the mixing valve delayed entering the fully open state. As for t0, the main priority is emission, dynamics and control stability are ranked from high to low priority, and the mixing valve outlet pressure fluctuation is guaranteed not to exceed ±20kPa / 10ms. The current state is in the preliminary mixing valve delayed entering the fully open X state (from the above description, X is one, two, three and four), then the corresponding t0 = t0-X. t0-4 < t0-3 < t0-2 < t0-1, and t0-4 = 0.03s, t0-3 = 0.08s, t0-2 = 0.1s, t0-4 = 0.12s.

[0189] If the previous state is that the preliminary mixing valve is delayed to enter the fully open state, and the current state is that the preliminary mixing valve enters the fully open state in advance, the final mixing valve state first enters the normal control state of the mixing valve and maintains for a period of time t1, and is divided into the following situations:

[0190] A) If the preliminary mixing valve enters the fully open state in advance before the end of time t1 (i.e., the preliminary mixing valve enters the fully open state in advance 1 is adjusted to the preliminary mixing valve enters the fully open state in advance 2, for example), the final mixing valve state is immediately changed to the mixing valve enters the fully open state in advance.

[0191] B) If the preliminary mixing valve enters the fully open state ahead of schedule and no change occurs before the end of time t1, or if the preliminary mixing valve enters the fully open state later than scheduled, the final mixing valve state will still be the normal control state of the mixing valve.

[0192] C) If after the t1 time is over, the final mixing valve state is immediately updated to the mixing valve entering the fully open state in advance. As for the main priority dynamics and control stability of t0, they are ranked from high to low priority, and the mixing valve outlet pressure fluctuation is guaranteed not to exceed ±20kPa / 10ms. The initial mixing valve is currently in the delayed entry into the fully open Y state (from the above description, Y is one or two), then the corresponding t1 = t1-Y. t1-1 < t1-2, and t1-1 = 0.03s, t1-2 = 0.05s. It should be noted that t0-4 is the minimum, that is, the improvement of emissions is prioritized.

[0193] In the transition process from the mixing valve being partially open to being fully open, the final mixing valve opening change rate dpct MGVNew :

[0194] (1) When the final mixing valve state is the fully open state under normal control of the mixing valve, dpct MGVNew =dpct MGVRaw ;

[0195] (2) When the final mixing valve state is when the mixing valve enters the fully open state in advance, dpct MGVNew =dpct MGVRaw ×r1;

[0196] (3) When the final mixing valve state is that the mixing valve is delayed to enter the fully open state, dpct MGVNew =dpct MGVRaw ×r2.

[0197] Embodiment 2

[0198] The present invention also provides an electronic device, comprising: a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; a computer program is stored in the memory, and when the program is executed by the processor, the processor executes the steps of the mixing valve opening dynamic control method.

[0199] Embodiment 3

[0200] The present invention also provides a computer-readable storage medium on which executable instructions are stored. When the instructions are executed by a processor, the processor implements the mixing valve opening dynamic control method.

[0201] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0202] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0203] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0204] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0205] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A method for dynamically controlling the opening of a mixing valve, characterized in that: include: Obtain the mixing valve opening and change rate when the mixing valve is in a transitional working condition from non-fully open to fully open; Determining the rate at which the mixing valve is accelerated to fully open based on the intake responsiveness requirement, which is set to a multiplication correction factor of one; Determine the rate at which the mixing valve is slowed down to full opening based on the control stability angle, set as a multiplication correction factor of two; The final mixing valve opening change rate when the mixing valve enters the full opening process is determined according to the multiplication correction coefficient one and the multiplication correction coefficient two.

2. The method for dynamic control of mixing valve opening according to claim 1, characterized in that: The multiplication correction coefficient r1=r11×r12, wherein r11 and r12 are both sub-correction coefficients.

3. The method for dynamic control of mixing valve opening according to claim 2, characterized in that: The method for determining the sub-correction coefficient r11 is as follows: When one of the following conditions is met, (1) Throttle full open time ratio Not less than 0.05, and the difference rate of air intake Not less than 0.05; (2) The engine speed is not less than 1000 rpm, and the boost pressure difference rate Not less than 0.1; Otherwise, when the above conditions are not met, r11 = 1; In the formula, the throttle full open time ratio t is the continuous time when the throttle enters the fully open state ThrWOT The maximum time of throttle valve fully open is t ThrWOTMax ratio; intake volume difference rate The target fresh air intake density rho entering the cylinder Dsrd The actual fresh air intake density rho Act The difference rho Dsrd -rho Act The fresh air intake density rho of the target cylinder Dsrd ratio; Characteristic coefficient The throttle valve fully open time ratio Difference rate with intake volume coefficient of determination is the boost pressure difference rate A coefficient determined by the engine speed n.

4. The method for dynamic control of mixing valve opening according to claim 3, characterized in that: The coefficient The calibration method is to adjust the throttle full opening time ratio at different engine speeds and stable boost pressure response accuracy. and intake volume difference rate Perform calibration.

5. The method for dynamic control of mixing valve opening according to claim 3, characterized in that: The coefficient The calibration method is to set the target fresh air intake density rho at each fixed engine speed, when the throttle is not fully open, and the target fresh air intake density rho is Dsrd The actual fresh air intake density rho Act Under the premise of small, by adjusting the difference rate of different boost pressure Perform calibration.

6. The method for dynamic control of mixing valve opening according to claim 2, characterized in that: The method for determining the sub-correction coefficient r12 is as follows: When one of the following conditions is met, (1) Target EGR rate r EGRDsrd Not less than 0.15, and the transient rate of intake flow Less than -0.05; (2) The engine speed is not less than 1000 rpm, and the EGR rate difference rate Less than ±0.015; Otherwise, when the above conditions are not met, r12 = 1; In the formula, the characteristic coefficient is the target EGR rate r EGRDsrd and the transient rate of intake air flow coefficient of determination EGR rate difference rate Coefficient determined by engine speed n; EGR rate difference r EGRDsrd -r EGRAct is the target EGR rate r EGRDsrd and the actual EGR rate r EGRAct difference.

7. The method for dynamic control of mixing valve opening according to claim 1, characterized in that: The multiplication correction coefficient r2=r21×r22×r23×r24, wherein r21, r22, r23 and r24 are all pressure fluctuation correction coefficients.

8. The method for dynamic control of mixing valve opening according to claim 7, characterized in that: The method for determining the pressure fluctuation correction coefficient r21 is as follows: When one of the following conditions is met, (1) Throttle inlet pressure fluctuation rate The time not less than 0.05 exceeds 0.2s; (2) Mixing valve outlet pressure fluctuation rate The time not less than 0.05 exceeds 0.5s; Otherwise, when the above conditions are not met, r21 = 1; p preFilter (N)=K pre ×[p pre (N)-p preFilter (N-1)]+p preFilter (N-1) In the formula, p pre is the intake pressure at the throttle inlet, p pre (N) is the throttle outlet intake pressure at the Nth sampling cycle, p preFilter is the throttle inlet pressure after first-order low-pass filtering, p preFilter (N) is the filtered throttle inlet intake pressure of the Nth sampling period, p preFilter (N-1) is the filtered throttle inlet intake pressure of the N-1th sampling period, N = 1, 2, 3..., p preFilter (0) is equal to the throttle inlet intake pressure p at the 0th sampling cycle pre (0); Where m is the number of engine cylinders, n is the engine speed, k pre is the throttle inlet intake pressure filter coefficient; p aftMixFilter (N)=K aftMix ×[p aftMix (N)-p aftMixFilter (N-1)]+p aftMixFilter (N-1) In the formula, p aftMix is the outlet pressure of the mixing valve, p aftMix (N) is the outlet pressure of the mixing valve at the Nth sampling period (the sampling period in this example is 10ms), p aftMixFilter is the outlet pressure of the mixing valve after first-order low-pass filtering, p preFilter (N) is the filtered outlet pressure of the mixing valve in the Nth sampling period, p preFilter (N-1) is the outlet pressure of the mixing valve after filtering in the N-1th sampling period, N = 1, 2, 3..., p preFilter (0) is equal to the mixing valve outlet pressure p at the 0th sampling cycle aftMix (0); Where m is the number of engine cylinders, n is the engine speed, k aftMix is the mixing valve outlet pressure filtering coefficient; is the throttle inlet pressure fluctuation rate Mixing valve outlet pressure fluctuation rate Determined coefficient.

9. The method for dynamic control of mixing valve opening according to claim 7, characterized in that: The method for determining the pressure fluctuation correction coefficient r22 is as follows: To meet the mixing valve pressure ratio Less than 0.2, and the mixing valve outlet pressure change rate dp aftMix When it is greater than the preset value, Otherwise r22=1; Characteristic coefficient The calibration basis is to ensure that the EGR rate difference rate is While not exceeding the preset value (±0.015), when the engine speed is stable and the engine target boost pressure is stable, the supercharger inlet pressure fluctuation range exceeds ±2kPa for no more than 0.1s.

10. The method for dynamic control of mixing valve opening according to claim 7, characterized in that: The method for determining the pressure fluctuation correction coefficient r23 is as follows: When one of the following conditions is met, (1) Throttle full-close time ratio Not less than 0.05, and the difference rate of air intake Less than -0.05; (2) The engine speed is not less than 1000 rpm, and the boost pressure difference rate Less than -0.1; Otherwise, when the above conditions are not met, r23 = 1; In the formula, the throttle full closing time ratio t is the continuous time that the throttle enters the fully closed state ThrMin The maximum time t of throttle valve fully closed ThrMinMax ratio; intake volume difference rate The target fresh air intake density rho entering the cylinder Dsrd The actual fresh air intake density rho Act The difference rho Dsrd -rho Act The fresh air intake density rho of the target cylinder Dsrd ratio; Characteristic coefficient The throttle valve fully closed time ratio Difference rate with intake volume coefficient of determination is the boost pressure difference rate ) is a coefficient determined by the engine speed n.

11. The method for dynamic control of mixing valve opening according to claim 7, characterized in that: The method for determining the pressure fluctuation correction coefficient r24 is as follows: To meet the gas volume entering the cylinder dm Cyl The fluctuation exceeds 20mgpl / 10ms continuously for a period exceeding the preset value, and the air-fuel ratio difference rate The time that the temperature is continuously less than -0.2 exceeds the preset value, and the cylinder inlet temperature T Port When the temperature is greater than 50°C and the target EGR rate does not exceed the preset value, Otherwise, r24=1; In the formula, the cylinder flow fluctuation rate is is the fresh air intake flow rate dm entering the cylinder during the current sampling period Cyl Compared with the fresh air intake flow rate dm entering the cylinder in the previous sampling cycle Cyl (z)dm Cyl -dm Cyl (z) and the fresh air intake flow rate dm entering the cylinder during the current sampling period Cyl ratio; air-fuel ratio difference rate is the target air-fuel ratio r AFRDsrd The actual air-fuel ratio AFRAct The difference AFRDsrd -r AFRAct and the target air-fuel ratio r AFRDsrd The ratio of is the cylinder flow fluctuation rate Difference rate of air-fuel ratio coefficient of determination Air-fuel ratio difference and cylinder inlet temperature T Port Determined coefficient.

12. The method for dynamic control of mixing valve opening according to claim 1, characterized in that: In the method for determining the final mixing valve opening change rate when the mixing valve enters the fully open process according to the multiplication correction coefficient 1 and the multiplication correction coefficient 2, If the multiplication correction coefficient is greater than 1, it indicates that the preliminary mixing valve enters the fully open state in advance; If the multiplication correction factor 1 is not greater than 1, and the multiplication correction factor 2 is less than 1, it is characterized that the preliminary mixing valve is delayed in entering the fully open state; If the above two conditions are not met, it indicates that the preliminary mixing valve enters the normal control state.

13. The method for dynamic control of mixing valve opening according to claim 11, characterized in that: In the method for determining the final mixing valve opening change rate when the mixing valve enters the fully open process according to the multiplication correction coefficient 1 and the multiplication correction coefficient 2, When the final mixing valve state is the mixing valve fully open state under normal control, dpct MGVNew =dpct MGVRaw ; The final mixing valve state is when the mixing valve enters the fully open state in advance, dpct MGVNew =dpct MGVRaw ×r1; The final mixing valve state is that the mixing valve is delayed to enter the fully open state, dpct MGVNew =dpct MGVRaw ×r2; Where, dpct MGVNew is the final mixing valve opening change rate, dpct MGVRaw is the rate of change of the mixing valve opening when the mixing valve is in a transitional condition from non-fully open to fully open, r1 is the multiplication correction coefficient one, and r2 is the multiplication correction coefficient two.

14. An electronic device, comprising: A processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; characterized in that a computer program is stored in the memory, and when the program is executed by the processor, the processor executes the steps of the method for dynamic control of the mixing valve opening according to any one of claims 1 to 13.

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