Control method and system for accelerating opening degree request for opening mixing valve

Abstract

The invention discloses a request control method and system for accelerating opening degree of a mixing valve, the mixing valve of a vehicle is in a transition working condition from non-full-opening to full-opening, and according to a first characteristic coefficient determined by a throttle valve full-opening time ratio and a steam admission amount difference rate, and a second characteristic coefficient determined by combining a boost pressure difference rate and an engine rotating speed, the first characteristic coefficient and the second characteristic coefficient are calculated; obtaining a first correction coefficient; a second correction coefficient is obtained according to a third characteristic coefficient determined by the target EGR rate and the air inlet flow transient rate and a fourth characteristic coefficient determined by combining the EGR rate difference rate and the engine rotating speed; obtaining a multiplication correction coefficient according to the first correction coefficient, the second correction coefficient and the learning updating coefficient; and determining the opening change rate of the mixing valve according to the multiplication correction coefficient so as to control the mixing valve. According to the method, the opening change rate of the mixing valve can be 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 in particular to a method and system for controlling a mixing valve opening request to accelerate the opening. 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 EGR rate. In the process of the mixing valve changing from fully open to partially open, it is necessary to balance the dynamics and optimize the mixing valve opening rate from the perspective of improving control stability.

[0003] The Chinese invention patent CN202011247319.6 discloses a method and system for calculating a target EGR rate. The patent calculates the initial target EGR rate from the throttle opening, manifold pressure difference, and minimum ignition angle. It can accurately calculate the target EGR rate and introduce EGR control activation conditions to perform secondary corrections on the final target EGR rate. However, it does not consider the control accuracy of the target opening of the mixing valve.

[0004] The Chinese invention patent CN202110184826.8 discloses a method and system for controlling the target opening of an EGR mixing valve, which can correct the target opening of the mixing valve according to various operating parameters. However, the patent does not consider the dynamic closed-loop control of the target opening of the mixing valve.

[0005] In summary, it is urgent to propose a method for accelerating the opening request of the mixing valve to solve the problems of control stability and dynamics in the process. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method and system for accelerating the opening of a mixing valve opening request control in view of the defects in the prior art.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] The present invention provides a method for controlling a mixing valve opening request to accelerate the opening, wherein the mixing valve of a vehicle is in a transitional operating state from a non-fully open state to a fully open state, comprising:

[0009] If the first correction coefficient update condition is met, the first correction coefficient is obtained according to the first characteristic coefficient determined by the throttle full opening time ratio and the steam intake amount difference rate, combined with the second characteristic coefficient determined by the boost pressure difference rate and the engine speed; otherwise, the first correction coefficient is set to 1;

[0010] If the second correction coefficient update condition is met, the second correction coefficient is obtained according to the third characteristic coefficient determined by the target EGR rate and the transient rate of the intake air flow, combined with the fourth characteristic coefficient determined by the EGR rate difference rate and the engine speed; otherwise, the second correction coefficient is set to 1;

[0011] Obtaining a multiplication correction coefficient according to the first correction coefficient, the second correction coefficient and the learning update coefficient;

[0012] The mixing valve opening change rate is determined according to the multiplication correction coefficient, and then the mixing valve is controlled.

[0013] Furthermore, the first correction coefficient update condition of the present invention includes:

[0014] The throttle full opening time ratio is not less than a certain threshold, and the intake volume difference rate is not less than a certain threshold;

[0015] or the engine speed is not less than a certain threshold, and the boost pressure difference rate is not less than a certain threshold;

[0016] Among them, the throttle full-open time ratio is the ratio of the continuous time that the throttle enters the fully-open state to the maximum time that the throttle is fully open; the intake volume difference rate is the ratio of the difference between the target fresh air intake density entering the cylinder and the actual fresh air intake density entering the cylinder to the target fresh air intake density entering the cylinder; the boost pressure difference rate is the ratio of the boost pressure difference to the target boost pressure.

[0017] Furthermore, the method for obtaining the first correction coefficient of the present invention includes:

[0018] The first characteristic coefficient is obtained through calibration, and the boost pressure response accuracy is stabilized at various engine speeds. The calibration is performed by adjusting different throttle full-open time ratios and intake volume difference rates to ensure that the difference between the engine target torque and the actual torque during the transition from the non-full-open to the full-open mixing valve is controlled within a certain threshold and does not exceed a certain continuous time;

[0019] The second characteristic coefficient is obtained by calibration. Under the premise that the throttle valve is not fully open and the target fresh air intake density entering the cylinder and the actual fresh air intake density entering the cylinder are less than a certain difference, the calibration is performed by adjusting different boost pressure difference rates to ensure that the difference between the target boost pressure and the actual boost pressure exceeds a certain threshold and does not exceed a certain continuous time.

[0020] The first characteristic coefficient is multiplied by the second characteristic coefficient to obtain a first correction coefficient.

[0021] Furthermore, the first characteristic coefficient and the second characteristic coefficient of the present invention are both set with a certain adjustment range.

[0022] Furthermore, when the fluctuation of the intake air amount difference rate of the present invention does not exceed a preset value, the first characteristic coefficient is not updated.

[0023] Furthermore, in the present invention, when the fluctuation of the engine speed does not exceed a preset value, and the fluctuation of the boost pressure difference rate does not exceed a preset value, the second characteristic coefficient is not updated.

[0024] Furthermore, the second correction coefficient update condition of the present invention includes:

[0025] The target EGR rate is not less than a certain threshold, and the transient rate of the intake air flow is less than a certain threshold;

[0026] or the engine speed is not less than a certain threshold, and its EGR rate difference rate is less than a certain threshold;

[0027] Among them, the intake flow transient rate is the ratio of the intake flow difference to the target intake flow, where the intake flow difference is the difference between the target intake flow and the actual intake flow; the EGR rate difference rate is the ratio of the EGR rate difference to the target boost pressure, where the EGR rate difference is the difference between the target EGR rate and the actual EGR rate.

[0028] Furthermore, the method for obtaining the second correction coefficient of the present invention includes:

[0029] The third characteristic coefficient is obtained through calibration. Under the premise that the EGR rate response accuracy meets the requirements at various engine speeds, calibration is performed by adjusting different target EGR rates and intake air flow transient rates to ensure that the difference between the engine target torque and the actual torque is controlled within a certain threshold and does not exceed a certain continuous time during the transition process from the non-fully open to the fully open mixing valve.

[0030] The fourth characteristic coefficient is obtained through calibration. Under the premise of stable target EGR rate and stable intake air flow transient rate at various engine speeds, the EGR valve is adjusted to achieve different EGR rate difference rates for calibration, ensuring that the engine fuel consumption point is at the lowest level;

[0031] The third characteristic coefficient is multiplied by the fourth characteristic coefficient to obtain a second correction coefficient.

[0032] Furthermore, the third characteristic coefficient and the fourth characteristic coefficient of the present invention are both set with a certain adjustment range.

[0033] Furthermore, in the present invention, when the target EGR rate fluctuation does not exceed a preset value, and the intake air flow transient rate fluctuation does not exceed a preset value, the third characteristic coefficient is not updated.

[0034] Furthermore, in the present invention, when the engine speed fluctuation does not exceed a preset value, and the target EGR rate fluctuation does not exceed a preset value, the fourth characteristic coefficient is not updated.

[0035] Furthermore, the method for obtaining the multiplication correction coefficient of the present invention includes:

[0036] r1=r11×r12×(1+r A dapt1)

[0037] Among them, r1 is the multiplication correction coefficient, r11 is the first correction coefficient, r12 is the second correction coefficient, r Adapt1 To learn the update coefficient, its default value is 0 and is saved after the vehicle is powered off.

[0038] Furthermore, the update condition of the learning update coefficient of the present invention is to satisfy the following conditions at the same time:

[0039] The mixing valve is in the transition process from partially open to fully open;

[0040] The supercharger is in the closed-loop control active state;

[0041] The absolute value of the engine target intake pressure change rate exceeds the preset value;

[0042] The absolute value of the engine torque change rate exceeds a preset value;

[0043] The engine mileage corresponding to the learning coefficient not being updated exceeds the preset value.

[0044] Furthermore, the updating method of the learning update coefficient of the present invention includes:

[0045] When the following conditions are met at the same time:

[0046] The difference between the engine target torque and the actual torque exceeds a certain threshold and lasts for a certain continuous time;

[0047] The difference between the target opening of the mixing valve and the actual opening of the mixing valve does not exceed the preset value;

[0048] The difference between the target EGR rate and the actual EGR rate does not exceed the preset value;

[0049] The difference between the target opening change rate of the mixing valve and the actual opening change rate of the mixing valve does not exceed a preset value;

[0050] Then r A dapt1=r A dapt1(z)+0.1, where r A dapt1(z) is the learning update coefficient obtained from the previous learning.

[0051] Furthermore, the updating method of the learning update coefficient of the present invention includes:

[0052] When the following conditions are met at the same time:

[0053] The difference between the target engine torque and the actual engine torque exceeds a certain threshold and does not exceed a certain continuous time;

[0054] The difference between the target boost pressure and the actual boost pressure exceeds a certain threshold and does not exceed a certain continuous time;

[0055] The difference between the target EGR rate and the actual EGR rate exceeds the preset value;

[0056] The difference between the target opening of the mixing valve and the actual opening of the mixing valve exceeds the preset value;

[0057] The difference between the target opening change rate of the mixing valve and the actual opening change rate of the mixing valve exceeds a preset value;

[0058] Then r A dapt1=r A dapt1(z)-0.06, where r A dapt1(z) is the learning update coefficient obtained from the previous learning.

[0059] The present invention provides a control system for accelerating the opening of a mixing valve opening request, comprising:

[0060] a memory for storing executable computer programs;

[0061] The processor is used to implement the above-mentioned method for accelerating the opening of the mixing valve opening request control when executing the executable computer program stored in the memory.

[0062] The beneficial effects produced by the present invention are:

[0063] 1. The present invention optimizes the target opening rate of the mixing valve when the mixing valve is requested to enter the full opening process, and further improves the control stability, dynamics and other problems in the control process.

[0064] 2. The present invention proposes a method for determining a first correction coefficient based on relevant parameters such as throttle characteristics, gas volume characteristics, and boost characteristics. The first correction coefficient can be used to effectively control relevant characteristics.

[0065] 3. Based on relevant parameters such as intake flow characteristics and EGR characteristics, the present invention proposes a method for determining the second correction coefficient, and the relevant characteristics can be effectively controlled through the second correction coefficient.

[0066] 4. Based on the first correction coefficient, the second correction coefficient and the learning update coefficient, the present invention proposes a method for determining the final multiplication correction coefficient. Through the final multiplication correction coefficient, the rate of change of the mixing valve opening can be accurately controlled.

[0067] 5. The present invention also proposes conditions and methods for updating the learning update coefficient. By updating and learning the learning update coefficient in each driving cycle, the control accuracy can be further improved.

[0068] In summary, the present invention is based on improving power, balancing the control accuracy of the EGR system and improving the control accuracy of the intake system, and optimizes the control of the mixing valve opening rate when the mixing valve changes from non-fully open to fully open. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0070] Figure 1 is a low-pressure EGR system architecture diagram of an embodiment of the present invention;

[0071] Figure 2 is a method flow chart of an embodiment of the present invention;

[0072] Figure 3 is a multiplication correction coefficient update flow chart of an embodiment of the present invention;

[0073] Figure 4 It is a system block diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0074] 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.

[0075] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0076] Example 1

[0077] like Figure 1 The following is a low-pressure EGR system architecture according to an embodiment of the present invention.

[0078] The low-pressure EGR system includes, air filter, mixing valve, supercharger compressor, throttle, engine, supercharger turbine, catalyst, particulate matter trap, EGR cooler, EGR valve, EGR temperature sensor, EGR differential pressure sensor, flow meter and linear oxygen sensor.

[0079] 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, mixing valve, flow meter and oxygen sensor; the flow meter is installed between the air filter and the mixing valve to detect the fresh air flow entering the engine; 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 oxygen sensor is installed between the compressor and the throttle, close to the throttle, and is used to detect the mixed gas flow entering the cylinder; the EGR cooler is used to cool the exhaust gas to facilitate increasing the exhaust gas flow and reducing 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.

[0080] In patent CN202110184826.8 "Method for determining the target opening of the mixing valve of the EGR system" and patent CN202110184815.X "Method for determining the activation state of the mixing valve of the low-pressure EGR system", transition control is mentioned in the process of the mixing valve changing from non-fully open (activated state) to fully open (activated), and the transition change of the target opening of the mixing valve is determined.

[0081] like Figure 2 As shown, in the embodiment of the present invention, it is assumed that the current mixing valve is in a transitional state from non-fully open to fully open based on the current public technology, and the current mixing valve opening is pct MGVRaw , and the rate of change is dpct MGVRaw .

[0082] The speed at which the mixing valve accelerates to full opening is determined based on the intake responsiveness requirement (which directly affects the dynamic responsiveness) and is set as the 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 × (1 + r A dapt1). Among them:

[0083] If the first correction coefficient update condition is met, the first correction coefficient is obtained according to the first characteristic coefficient determined by the throttle full opening time ratio and the steam intake amount difference rate, combined with the second characteristic coefficient determined by the boost pressure difference rate and the engine speed; otherwise, the first correction coefficient is set to 1;

[0084] If the second correction coefficient update condition is met, the second correction coefficient is obtained according to the third characteristic coefficient determined by the target EGR rate and the transient rate of the intake air flow, combined with the fourth characteristic coefficient determined by the EGR rate difference rate and the engine speed; otherwise, the second correction coefficient is set to 1;

[0085] Obtaining a multiplication correction coefficient according to the first correction coefficient, the second correction coefficient and the learning update coefficient;

[0086] The mixing valve opening change rate is determined according to the multiplication correction coefficient, and then the mixing valve is controlled.

[0087] By using the method of the embodiment of the present invention, the target opening rate of the mixing valve during the mixing valve request entering the full opening process can be optimized to further improve the control stability, dynamics and other issues in the control process.

[0088] Example 2

[0089] Based on Example 1, this embodiment of the present invention provides a method for determining a first correction coefficient, which specifically includes:

[0090] First, the embodiment of the present invention needs to determine the first correction coefficient update condition, including:

[0091] The throttle full opening time ratio is not less than a certain threshold, and the intake volume difference rate is not less than a certain threshold;

[0092] or the engine speed is not less than a certain threshold, and the boost pressure difference rate is not less than a certain threshold;

[0093] Among them, the throttle full-open time ratio is the ratio of the continuous time that the throttle enters the fully-open state to the maximum time that the throttle is fully open; the intake volume difference rate is the ratio of the difference between the target fresh air intake density entering the cylinder and the actual fresh air intake density entering the cylinder to the target fresh air intake density entering the cylinder; the boost pressure difference rate is the ratio of the boost pressure difference to the target boost pressure.

[0094] In a preferred embodiment of the present invention, the method for determining the first correction coefficient r11 is as follows:

[0095] When one of the following conditions is met,

[0096] Full Throttle Open Time Ratio Not less than 0.05, and the difference rate of air intake Not less than 0.05;

[0097] Or the engine speed is not less than 1000rpm, and the boost pressure difference rate Not less than 0.1.

[0098]

[0099] Otherwise, when the above conditions are not met, r11=1.

[0100] If the above conditions are met, the next step describes the detailed method of obtaining r11:

[0101] 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.

[0102] 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 throttling loss of the mixing valve, and responds to the power torque demand;

[0103] The first characteristic coefficient is obtained through calibration, and the boost pressure response accuracy is stabilized at various engine speeds. The calibration is performed by adjusting different throttle full-open time ratios and intake volume difference rates to ensure that the difference between the engine target torque and the actual torque during the transition from the non-full-open to the full-open mixing valve is controlled within a certain threshold and does not exceed a certain continuous time;

[0104] In a preferred embodiment of the present invention, 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.

[0105] 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)

[0106] 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:

[0107] 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.

[0108] 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.

[0109] The second characteristic coefficient is obtained by calibration. Under the premise that the throttle valve is not fully open and the target fresh air intake density entering the cylinder and the actual fresh air intake density entering the cylinder are less than a certain difference, the calibration is performed by adjusting different boost pressure difference rates to ensure that the difference between the target boost pressure and the actual boost pressure exceeds a certain threshold and does not exceed a certain continuous time.

[0110] In a preferred embodiment of the present invention, 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.

[0111] 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.

[0112] 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:

[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 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.

[0114] Example 3

[0115] Based on Example 2, this embodiment of the present invention provides a method for determining a second correction coefficient, which specifically includes:

[0116] First, the embodiment of the present invention requires a second correction coefficient update condition, including:

[0117] The target EGR rate is not less than a certain threshold, and the transient rate of the intake air flow is less than a certain threshold;

[0118] or the engine speed is not less than a certain threshold, and its EGR rate difference rate is less than a certain threshold;

[0119] Among them, the intake flow transient rate is the ratio of the intake flow difference to the target intake flow, where the intake flow difference is the difference between the target intake flow and the actual intake flow; the EGR rate difference rate is the ratio of the EGR rate difference to the target boost pressure, where the EGR rate difference is the difference between the target EGR rate and the actual EGR rate.

[0120] In a preferred embodiment of the present invention, the method for determining the second correction coefficient r12 is as follows:

[0121] When one of the following conditions is met,

[0122] Target EGR rate r EGRDsrd Not less than 0.15, and the transient rate of intake flow Less than -0.05;

[0123] Or the engine speed is not less than 1000rpm, and the EGR rate difference rate Less than ±0.015.

[0124]

[0125] Otherwise, when the above conditions are not met, r12=1.

[0126] If the above conditions are met, the next step describes the detailed method of obtaining r12:

[0127] 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;

[0128] The third characteristic coefficient is obtained through calibration. Under the premise that the EGR rate response accuracy meets the requirements at various engine speeds, calibration is performed by adjusting different target EGR rates and intake air flow transient rates to ensure that the difference between the engine target torque and the actual torque is controlled within a certain threshold and does not exceed a certain continuous time during the transition process from the non-fully open to the fully open mixing valve.

[0129] In a preferred embodiment of the present invention, 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.

[0130] 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).

[0131] 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:

[0132] 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.

[0133] 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.

[0134]

[0135] The fourth characteristic coefficient is obtained through calibration. Under the premise of stable target EGR rate and stable intake air flow transient rate at various engine speeds, the EGR valve is adjusted to achieve different EGR rate difference rates for calibration, ensuring that the engine fuel consumption point is at the lowest level;

[0136] In a preferred embodiment of the present invention, 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.

[0137] 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:

[0138] 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.

[0139] The above completes the description of the multiplication correction factor r1 for accelerating full opening.

[0140] Example 4

[0141] Based on the embodiments 1-3, the embodiment of the present invention provides a method for determining the learning update coefficient and the update conditions. In the transition process from the mixing valve being partially open to being fully open, the final mixing valve opening change rate dpct MGVNew Determined according to r1, such as Figure 3 As shown. Intake air flow transient rate The difference between the throttle gas mass flow rate and the cylinder gas mass flow rate divided by the throttle gas mass flow rate. MGVNew Equal to dpct MGVRaw Multiply by r1.

[0142] r1=r11×r12×(1+r A dapt1), where r A Dapt1 is the learning update coefficient, and its default value is 0. It can be saved after the vehicle is powered off. Its update method can only be activated when the following conditions (engine is in a large transient state) are met at the same time:

[0143] 1. The mixing valve is in the transition process from non-fully open to fully open;

[0144] 2. The supercharger is in the closed-loop control activation state;

[0145] 3. The absolute value of the engine target intake pressure change rate exceeds the preset value, which is 25kPa / 10ms in this example;

[0146] 4. The absolute value of the engine requested torque change rate exceeds a preset value, which in this example is 30 Nm / 10 ms.

[0147] 5. The engine mileage corresponding to the learning coefficient not being updated exceeds the preset value, which is 20,000 kilometers in this example.

[0148] When the above conditions are met at the same time, then:

[0149] In the first case, the torque responsiveness is poor, but the EGR rate responsiveness is good:

[0150] 1) The difference between the engine target torque and the actual torque exceeds ±5Nm for more than 0.7s;

[0151] 2) The difference between the target opening of the mixing valve and the actual opening of the mixing valve does not exceed the preset value (±1% in this example)

[0152] 3) The difference between the target EGR rate and the actual EGR rate does not exceed the preset value ±0.1;

[0153] 4)dpct MGVNew -dpct MGVRaw The difference does not exceed the preset value, in this example -15% / 10ms

[0154] It is necessary to further improve the torque response accuracy.

[0155] r A dapt1=r A dapt1(z)+0.1, where r A dapt1(z) is the learning update coefficient obtained from the previous learning.

[0156] In the second case, the torque responsiveness is good, but the EGR rate responsiveness is poor:

[0157] 1) The difference between the target engine torque and the actual engine torque exceeds ±5Nm for no more than 0.5s;

[0158] 2) The difference between the target boost pressure and the actual boost pressure exceeds ±2kPa for no more than 0.3s

[0159] 3) The difference between the target EGR rate and the actual EGR rate exceeds the preset value, which is ±0.15 in this example;

[0160] 4) The difference between the target opening of the mixing valve and the actual opening of the mixing valve exceeds the preset value, which is ±1.5% in this example;

[0161] 5)dpct MGVNew -dpct MGVRaw The difference exceeds the preset value, which in this example is -15% / 10ms.

[0162] Then it is necessary to improve the EGR rate:

[0163] r A dapt1=r A dapt1(z)-0.06;

[0164] In other cases, r A dapt1=r A dapt1(z);

[0165] If the learning coefficient is updated, it will not be updated in this driving cycle.

[0166] Example 5

[0167] like Figure 4 As shown, the embodiment of the present invention provides a control system for accelerating the opening of a mixing valve opening request based on the embodiments 1-4, including:

[0168] A memory 21, used for storing executable computer programs;

[0169] The processor 22 is used to implement the above-mentioned method for accelerating the opening of the mixing valve opening request control when executing the executable computer program stored in the memory.

[0170] In this embodiment, the memory 21 (i.e., readable storage medium) includes flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory, etc.), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM). The memory 21 may also be an external storage device of the terminal device 20, such as a plug-in hard disk, a smart memory card (SmartMedia Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the terminal device 20. Of course, the memory 21 may also include both the internal storage unit of the terminal device 20 and its external storage device.

[0171] In some embodiments, the processor 22 may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chips. The processor 22 is generally used to control the overall operation of the computer device 20.

[0172] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0173] 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 method for accelerating the opening of a mixing valve opening request control, wherein the mixing valve of a vehicle is in a transitional operating state from a non-fully open state to a fully open state, characterized in that: include: If the first correction coefficient update condition is met, the first correction coefficient is obtained according to the first characteristic coefficient determined by the throttle full opening time ratio and the intake air volume difference rate, combined with the second characteristic coefficient determined by the boost pressure difference rate and the engine speed; otherwise, the first correction coefficient is set to 1; If the second correction coefficient update condition is met, the second correction coefficient is obtained by combining the third characteristic coefficient determined by the target EGR rate and the transient rate of the intake air flow rate with the fourth characteristic coefficient determined by the EGR rate difference rate and the engine speed; Otherwise the second correction coefficient is set to 1; Obtaining a multiplication correction coefficient according to the first correction coefficient, the second correction coefficient and the learning update coefficient; The mixing valve opening change rate is determined according to the multiplication correction coefficient, and then the mixing valve is controlled.

2. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 1, characterized in that: The first correction coefficient update condition includes: The throttle full opening time ratio is not less than a certain threshold, and the intake volume difference rate is not less than a certain threshold; or the engine speed is not less than a certain threshold, and the boost pressure difference rate is not less than a certain threshold; Among them, the throttle full-open time ratio is the ratio of the continuous time that the throttle enters the fully-open state to the maximum time that the throttle is fully open; the intake volume difference rate is the ratio of the difference between the target fresh air intake density entering the cylinder and the actual fresh air intake density entering the cylinder to the target fresh air intake density entering the cylinder; the boost pressure difference rate is the ratio of the boost pressure difference to the target boost pressure.

3. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 2, characterized in that: Method for obtaining the first correction coefficient include: The first characteristic coefficient is obtained through calibration, and the boost pressure response accuracy is stabilized at various engine speeds. The calibration is performed by adjusting different throttle full-open time ratios and intake volume difference rates to ensure that the difference between the engine target torque and the actual torque during the transition from the non-full-open to the full-open mixing valve is controlled within a certain threshold and does not exceed a certain continuous time; The second characteristic coefficient is obtained by calibration. Under the premise that the throttle valve is not fully open and the target fresh air intake density entering the cylinder and the actual fresh air intake density entering the cylinder are less than a certain difference, the calibration is performed by adjusting different boost pressure difference rates to ensure that the difference between the target boost pressure and the actual boost pressure exceeds a certain threshold and does not exceed a certain continuous time. The first characteristic coefficient is multiplied by the second characteristic coefficient to obtain a first correction coefficient.

4. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 3, characterized in that: The first characteristic coefficient and the second characteristic coefficient are both set with a certain adjustment range.

5. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 3, characterized in that: When the fluctuation of the intake air amount difference rate does not exceed the preset value, the first characteristic coefficient is not updated.

6. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 3, characterized in that: When the engine speed fluctuation does not exceed the preset value, and the boost pressure difference rate fluctuation does not exceed the preset value, the second characteristic coefficient is not updated.

7. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 1, characterized in that: The second correction coefficient update condition includes: The target EGR rate is not less than a certain threshold, and the transient rate of the intake air flow is less than a certain threshold; or the engine speed is not less than a certain threshold, and its EGR rate difference rate is less than a certain threshold; Among them, the intake flow transient rate is the ratio of the intake flow difference to the target intake flow, where the intake flow difference is the difference between the target intake flow and the actual intake flow; the EGR rate difference rate is the ratio of the EGR rate difference to the target boost pressure, where the EGR rate difference is the difference between the target EGR rate and the actual EGR rate.

8. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 7, characterized in that: Methods for obtaining the second correction coefficient include: The third characteristic coefficient is obtained through calibration. Under the premise that the EGR rate response accuracy meets the requirements at various engine speeds, calibration is performed by adjusting different target EGR rates and intake air flow transient rates to ensure that the difference between the engine target torque and the actual torque is controlled within a certain threshold and does not exceed a certain continuous time during the transition process from the non-fully open to the fully open mixing valve. The fourth characteristic coefficient is obtained through calibration. Under the premise of stable target EGR rate and stable intake air flow transient rate at various engine speeds, the EGR valve is adjusted to achieve different EGR rate difference rates for calibration, ensuring that the engine fuel consumption point is at the lowest level; The third characteristic coefficient is multiplied by the fourth characteristic coefficient to obtain a second correction coefficient.

9. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 8, characterized in that: The third characteristic coefficient and the fourth characteristic coefficient are both set with a certain adjustment range.

10. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 7, characterized in that: When the target EGR rate fluctuation does not exceed the preset value, and the intake air flow rate transient rate fluctuation does not exceed the preset value, the third characteristic coefficient is not updated.

11. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 7, characterized in that: When the engine speed fluctuation does not exceed the preset value, and the target EGR rate fluctuation does not exceed the preset value, the fourth characteristic coefficient is not updated.

12. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 1, characterized in that: Methods for obtaining the multiplication correction factor include: r1=r11×r12×(1+r A dapt1) Among them, r1 is the multiplication correction coefficient, r11 is the first correction coefficient, r12 is the second correction coefficient, r Adapt1 To learn the update coefficient, its default value is 0 and is saved after the vehicle is powered off.

13. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 12, characterized in that: The update conditions for learning update coefficients are as follows: The mixing valve is in the transition process from partially open to fully open; The supercharger is in the closed-loop control active state; The absolute value of the engine target intake pressure change rate exceeds the preset value; The absolute value of the engine torque change rate exceeds a preset value; The engine mileage corresponding to the learning coefficient not being updated exceeds the preset value.

14. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 13, characterized in that: The update methods for learning update coefficients include: When the following conditions are met at the same time: The difference between the engine target torque and the actual torque exceeds a certain threshold and lasts for a certain continuous time; The difference between the target opening of the mixing valve and the actual opening of the mixing valve does not exceed the preset value; The difference between the target EGR rate and the actual EGR rate does not exceed the preset value; The difference between the target opening change rate of the mixing valve and the actual opening change rate of the mixing valve does not exceed a preset value; Then r A dapt1=r A dapt1(z)+0.1, where r A dapt1(z) is the learning update coefficient obtained from the previous learning.

15. The method for controlling the opening request of a mixing valve when opening is accelerated according to claim 13, characterized in that: The update methods for learning update coefficients include: When the following conditions are met at the same time: The difference between the target engine torque and the actual engine torque exceeds a certain threshold and does not exceed a certain continuous time; The difference between the target boost pressure and the actual boost pressure exceeds a certain threshold and does not exceed a certain continuous time; The difference between the target EGR rate and the actual EGR rate exceeds the preset value; The difference between the target opening of the mixing valve and the actual opening of the mixing valve exceeds the preset value; The difference between the target opening change rate of the mixing valve and the actual opening change rate of the mixing valve exceeds a preset value; Then r A dapt1=r A dapt1(z)-0.06, where r A dapt1(z) is the learning update coefficient obtained from the previous learning.

16. A control system for accelerating the opening of a mixing valve opening request, characterized in that: include: a memory for storing executable computer programs; The processor is used to implement the accelerated opening mixing valve opening request control method as described in any one of claims 1 to 9 when executing the executable computer program stored in the memory.

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