CN118167515A - EGR closed-loop control method and device and vehicle - Google Patents

Abstract

The invention provides an EGR closed-loop control method and device and a vehicle, and relates to the technical field of vehicles. The method comprises the following steps: acquiring current operation information; estimating the current mixing point EGR rate by using an EGR rate estimator based on the manifold EGR rate to obtain a current mixing point EGR rate pre-estimate; estimating disturbance of a preset EGR system model by using a first observer based on the current EGR flow control quantity and the current mixing point EGR rate pre-estimation to obtain a first disturbance quantity; and obtaining a target EGR flow control amount according to the first disturbance amount and the target EGR rate, and controlling the opening of the EGR valve based on the target EGR flow control amount. The invention avoids the influence of the mixed transmission delay process on the control precision by eliminating the phase difference of the EGR rate of the manifold. Meanwhile, the system disturbance is estimated based on the first observer, so that the system disturbance is eliminated, the closed-loop control of the EGR rate is realized, and the accuracy of the system on the control of the EGR rate is improved.

Description

EGR closed-loop control method and device and vehicle

Technical Field

The invention relates to the technical field of vehicles, in particular to an EGR closed-loop control method and device and a vehicle.

Background

In order to effectively improve the fuel economy of the engine and reduce the emission of nitrogen oxides, an LP-EGR (Low Pressure-Exhaust Gas Recirculation) system can be adopted to re-introduce the exhaust gas into a Low-Pressure loop for recycling, which is beneficial to remarkably reducing the knocking tendency of a Low-speed large-load working condition, and can reduce pumping loss and heat transfer loss while reducing the fuel enrichment of a high-power working condition. Based on the above advantages, the LP-EGR system is widely applied to hybrid special engines which pursue extremely thermal efficiency.

For cost reasons, the existing LP-EGR system mainly calculates the EGR rate through a model, and the obtained EGR rate is mainly used for performing coordinated control such as VVT (Variable VALVE TIMING ), ignition angle, and control and correction of the supercharger. However, due to poor accuracy of the model used to calculate the EGR rate, closed-loop control of the EGR rate in the system cannot be realized based on the calculated EGR rate, resulting in low control accuracy of the system.

Disclosure of Invention

The problem to be solved by the invention is how to improve the control accuracy of an EGR system.

In order to solve the above problems, the present invention provides an EGR closed-loop control method, including:

Acquiring current operation information, wherein the current operation information comprises a target EGR rate, a manifold EGR rate and a current EGR flow control amount;

Estimating the current mixing point EGR rate by using a preset EGR rate estimator based on the manifold EGR rate to obtain a current mixing point EGR rate estimated value;

Estimating disturbance of a preset EGR system model by using a preset first observer based on the current EGR flow control quantity and the current mixing point EGR rate preset quantity to obtain a first disturbance quantity;

And obtaining a target EGR flow control amount according to the first disturbance amount and the target EGR rate, and controlling the opening of an EGR valve based on the target EGR flow control amount.

Optionally, the current operation information further includes a total air mixture amount; the estimating, based on the manifold EGR rate, the EGR rate at the current mixing point by using a preset EGR rate estimator to obtain a predicted amount of the EGR rate at the current mixing point, including:

inputting the total air mixing amount, the manifold EGR rate and the current EGR flow control amount into the EGR rate predictor to obtain the current mixing point EGR rate pre-estimation;

the EGR rate predictor satisfies:

Wherein y _P represents the current mixing point EGR rate pre-estimate; y ₁ represents the manifold EGR rate; y _m represents a manifold EGR rate estimated value obtained by modeling the total air-fuel mixture, the current EGR flow control amount and the preset EGR system model; t represents the current time; representing the delay time estimate.

Optionally, the estimating, by using a preset first observer, disturbance of a preset EGR system model based on the current EGR flow control amount and the current mixing point EGR rate preset amount to obtain a first disturbance amount includes:

Inputting the total air mixing amount, the current EGR flow control amount and the current mixing point EGR rate pre-estimated amount into the first observer to obtain the first disturbance amount, wherein the first observer is constructed based on the preset EGR system model;

The preset EGR system model satisfies:

Wherein x ₁ represents the current mixing point EGR rate for the state quantity selected by the system; x ₂ is a state quantity selected by the system and represents disturbance of the preset EGR system model; y ₂ is the output quantity selected by the system; f represents disturbance of the preset EGR system model; u is a control quantity selected by a system and represents the current EGR flow control quantity; h represents the derivative of f; a ₀ is a predicted value of a; b ₀ is a predicted value of b; a= -1/τ _mixing; τ _mixing represents a time constant; /(I) Representing the total air mixture amount;

the first observer satisfies:

Wherein z ₁ is an estimate of x ₁; z ₂ is an estimated value of x ₂, and z ₂ represents the first disturbance variable; y ₂ is equal to the current mixing point EGR rate pre-estimate; beta ₁ represents a first tuning parameter; beta ₂ represents a second tuning parameter.

Optionally, the current operating information further includes a manifold pressure measurement; before the controlling the EGR valve opening based on the target EGR flow control amount, further includes:

Based on the manifold pressure measurement value, estimating disturbance of a preset air inlet pressure model by using a preset second observer to obtain a second disturbance quantity;

An EGR flow area error is determined based on the second disturbance variable.

Optionally, based on the manifold pressure measurement, estimating, by using a preset second observer, a disturbance of a preset intake pressure model to obtain a second disturbance variable, including:

Inputting the manifold pressure measurement into the second observer to obtain the second disturbance variable;

The second observer satisfies:

Wherein, Representing the manifold pressure estimate; /(I)Representing a manifold pressure predicted value obtained through modeling of the preset intake pressure model; p _im represents the manifold pressure measurement; /(I)Representing the second disturbance variable; beta _p1 represents a third tuning parameter; beta _p2 represents a fourth tuning parameter.

Optionally, the current operation information further includes EGR valve operation information including EGR valve upstream pressure, EGR valve downstream pressure, EGR valve upstream temperature, and gas temperature; the determining an EGR flow area error based on the second disturbance variable includes:

Determining the EGR flow area error based on the second disturbance quantity, the EGR valve operation information and a preset system disturbance model;

The system disturbance model satisfies the following conditions:

Wherein f _p represents a disturbance of the preset intake pressure model; t _im represents the gas temperature; v _im denotes a preset intake manifold volume; Δa _egr represents the EGR flow area error; p _us represents the EGR valve upstream pressure, and P _ds represents the EGR valve downstream pressure; t _us represents the temperature upstream of the EGR valve; c _d denotes a preset flow coefficient.

Optionally, the obtaining the target EGR flow control amount according to the first disturbance amount and the target EGR rate includes:

inputting the first disturbance quantity, the target EGR rate and the pre-estimated current mixing point EGR rate into a preset controller model to obtain the target EGR flow control quantity;

the preset controller model satisfies:

Wherein u represents the target EGR flow control amount; x ^des represents the target EGR rate; Representing the current mixing point EGR rate pre-estimate; w represents disturbance of the preset EGR system model, which is equal to the first disturbance quantity; k _p represents the proportional gain.

Optionally, the controlling the EGR valve opening based on the target EGR flow control amount includes:

and determining an EGR valve initial opening value based on the target EGR flow control amount, correcting the EGR valve initial opening value according to the EGR flow area error to obtain an EGR valve target opening value, and controlling the EGR valve opening according to the EGR valve target opening value.

The invention is beneficial to providing an effective data base for closed-loop control of the subsequent EGR rate by acquiring the current operation information such as the target EGR rate, the manifold EGR rate, the current EGR flow control quantity and the like. The method has the advantages that the preset EGR rate predictor is utilized to estimate the current mixing point EGR rate, so that the manifold EGR rate phase difference caused by a long loop system from an exhaust manifold to an intake manifold is eliminated, the accuracy and the reliability of the current mixing point EGR rate prediction are ensured, and the combustion stability of the system under the transient working condition is improved. On the basis, inaccuracy of system modeling and internal and external interference of the system are uniformly regarded as disturbance items of the system model, and disturbance of the preset EGR system model is estimated by using a preset first observer, so that dependence of system control precision on model precision is reduced. Meanwhile, disturbance is estimated based on the current mixing point EGR rate pre-estimation and the current EGR flow control quantity of the elimination delay, so that the accuracy of the first disturbance quantity is improved, and the accuracy of a control system is improved. And finally, obtaining a target EGR flow control quantity according to the first disturbance quantity and the target EGR rate, so that the real-time estimation and elimination of the total disturbance caused by the modeling error and the external factors are realized, and the accuracy of the target EGR flow control quantity is improved. When the opening degree of the EGR valve is controlled based on the obtained target EGR flow control quantity, the EGR rate of the system can be enabled to be closer to the target EGR rate, so that closed-loop control of the EGR rate is realized, and the accuracy and reliability of the system for controlling the EGR rate are improved.

The invention also provides an EGR closed-loop control device, which comprises:

an acquisition module for acquiring current operation information including a target EGR rate, a manifold EGR rate, and a current EGR flow control amount;

The EGR rate estimating module is used for estimating the current mixing point EGR rate by using a preset EGR rate estimator based on the manifold EGR rate to obtain a current mixing point EGR rate estimated value;

The first observation module is used for estimating disturbance of a preset EGR system model by using a preset first observer based on the current EGR flow control quantity and the current mixing point EGR rate preset quantity to obtain a first disturbance quantity;

And the control module is used for obtaining a target EGR flow control amount according to the first disturbance amount, the current mixing point EGR rate pre-estimation amount and the target EGR rate and controlling the opening of the EGR valve based on the target EGR flow control amount.

The advantages of the EGR closed-loop control device provided by the present invention and the EGR closed-loop control method compared with the prior art are basically the same, and are not described in detail herein.

The invention also provides a vehicle comprising a memory for storing a computer program and a processor for implementing the EGR closed loop control method as described above when executing the computer program.

The advantages of the vehicle provided by the invention and the EGR closed-loop control method compared with the prior art are basically the same, and are not described in detail herein.

Drawings

FIG. 1 is a flow chart of an EGR closed loop control method in accordance with an embodiment of the present invention;

FIG. 2 is a schematic diagram of a hybrid transmission process of an EGR system in accordance with an embodiment of the present invention;

FIG. 3 is a schematic diagram of a control architecture corresponding to an EGR closed-loop control method according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of an EGR closed-loop control device in accordance with an embodiment of the present invention;

Fig. 5 is a schematic structural view of a vehicle according to an embodiment of the present invention.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. While the invention is susceptible of embodiment in the drawings, it is to be understood that the invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, but rather are provided to provide a more thorough and complete understanding of the invention. It should be understood that the drawings and embodiments of the invention are for illustration purposes only and are not intended to limit the scope of the present invention.

It should be understood that the various steps recited in the method embodiments of the present invention may be performed in a different order and/or performed in parallel. Furthermore, method embodiments may include additional steps and/or omit performing the illustrated steps. The scope of the invention is not limited in this respect.

The term "including" and variations thereof as used herein are intended to be open-ended, i.e., including, but not limited to. The term "based on" is based at least in part on. The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "alternative embodiments". Related definitions of other terms will be given in the description below. It should be noted that the terms "first," "second," and the like herein are merely used for distinguishing between different devices, modules, or units and not for limiting the order or interdependence of the functions performed by such devices, modules, or units.

It should be noted that references to "one", "a plurality" and "a plurality" in this disclosure are intended to be illustrative rather than limiting, and those skilled in the art will appreciate that "one or more" is intended to be construed as "one or more" unless the context clearly indicates otherwise.

As shown in fig. 1, an embodiment of the present invention provides an EGR closed-loop control method, including:

S1: current operation information is acquired, the current operation information including a target EGR rate, a manifold EGR rate, and a current EGR flow control amount.

Specifically, the target EGR rate referred to in this embodiment is typically generated by an ECU (Engine Control Unit ) indicating the EGR rate that the system is expected to achieve. The current EGR flow control amount referred to in this embodiment represents the target EGR flow control amount generated by the controller in the last control period. The manifold EGR rate referred to in this embodiment represents the manifold EGR rate calculated by the virtual EGR sensor constructed based on the EGR model.

In one embodiment, as shown in FIG. 2, the EGR exhaust gas from the EGR system, after meeting with fresh air at a meeting point, is routed through a mixing process and a delivery process to a manifold and finally into the engine cylinder for combustion. In FIG. 2Represents EGR flow,/>Representing mass flow rate measured by an airflow meter, EGR _comp representing junction EGR rate, EGR _t representing EGR rate without pipeline transfer delay after mixing (i.e., current mixing point EGR rate), EGR _im representing manifold EGR rate, 1/τ _mixing s+1 representing mixing process of exhaust gas,/>Representing a delay element. The hybrid transmission process of the EGR system may be modeled based on the above process to obtain a virtual EGR rate sensor:

Wherein, Indicating a total amount of air mixture approximately equal to the sum of the EGR exhaust gas amount and the fresh air amount.

In this embodiment, by acquiring current operation information such as the target EGR rate, the manifold EGR rate, and the current EGR flow control amount, it is advantageous to provide an effective data basis for closed-loop control of the subsequent EGR rate.

S2: based on the manifold EGR rate, estimating the current mixing point EGR rate by using a preset EGR rate estimator to obtain a current mixing point EGR rate pre-estimate.

Specifically, as shown in fig. 2, during the mixing transmission of the EGR system, the change of the operating condition faces a problem of long time delay due to the long-circuit system from the exhaust manifold to the intake manifold, and the manifold EGR rate obtained based on the virtual EGR sensor does not accurately reflect the undelayed EGR rate at the current mixing point. The phase difference of the manifold EGR rate needs to be eliminated through a preset EGR rate predictor, and the estimated value of the current mixing point EGR rate is obtained. The EGR rate estimator in this embodiment may be constructed based on a kalman filter or a smith estimator, and preferably the EGR rate estimator in this embodiment is constructed based on a smith estimator.

In this embodiment, the preset EGR rate predictor is used to estimate the current mixing point EGR rate, which is favorable to eliminating the manifold EGR rate phase difference caused by the long loop system from the exhaust manifold to the intake manifold, ensuring the accuracy and reliability of the current mixing point EGR rate prediction, and improving the combustion stability of the system under transient working conditions.

S3: based on the current EGR flow control quantity and the current mixing point EGR rate pre-estimated quantity, a preset first observer is utilized to estimate disturbance of a preset EGR system model, and a first disturbance quantity is obtained.

Specifically, in this embodiment, the preset EGR system model is obtained based on the modeling of the EGR exhaust gas mixing and transmitting process, and the transmission model of the EGR system may be converted into a time domain model:

Wherein τ _mixing represents a time constant; t represents the current time; τ _d represents the delay time.

Based on this, a state space equation of the preset EGR system can be constructed:

Wherein X is a state quantity selected by the system, Y is an output quantity selected by the system, and U is a control quantity selected by the system. In the EGR rate control problem, EGR _t (i.e., the current mixing point EGR rate) may be selected as the state quantity, EGR _im (i.e., the manifold EGR rate) may be selected as the output quantity, The control quantity (namely, EGR flow) is selected, disturbance (such as internal and external disturbance, unmodeled error and the like) of the system is considered, and the disturbance of the system is marked as W, so that a state space form of a preset EGR system model can be obtained:

wherein a= -1/τ _mixing; w represents a system disturbance.

The first observer referred to in this embodiment may be constructed based on a kalman filter or an ESO-extended state observer, and preferably the ESO-extended state observer is selected to construct the first observer in this embodiment. For example, the first observer may choose EGR _t as the state quantity to be observed,The control quantity is selected, and because the virtual EGR rate is adopted to estimate the current mixing point EGR rate in the embodiment, the estimated current mixing point EGR rate can be used as an actual measurement value of the current mixing point EGR rate, and the parameters of the observer are gradually optimized based on the error between the estimated current mixing point EGR rate and the estimated current mixing point EGR rate, so that the first observer can estimate the disturbance of the system more accurately, and the first disturbance quantity is obtained.

In this embodiment, inaccuracy of system modeling and internal and external interference of the system are regarded as disturbance items of the system model, and disturbance of the preset EGR system model is estimated by using a preset first observer, which is beneficial to reducing dependence of system control accuracy on model accuracy. On the basis, disturbance is estimated based on the current mixing point EGR rate pre-estimation and the current EGR flow control quantity of the elimination delay, so that the accuracy of the first disturbance quantity is improved, and the accuracy of a control system is improved.

S4: and obtaining a target EGR flow control amount according to the first disturbance amount and the target EGR rate, and controlling the opening of the EGR valve based on the target EGR flow control amount.

Specifically, since the preset EGR system model may be rewritten into a state space form, after the system disturbance is obtained, the control amount required by the system may be determined based on the target EGR rate and the first disturbance amount, and the target EGR flow control amount may be obtained. And the control of the EGR valve opening degree can be determined after the target EGR flow control amount is determined. For example, the target EGR flow control amount may be brought into an EGR valve throttle equation describing the EGR valve opening degree and the EGR flow, a desired EGR valve opening degree value may be determined, and the EGR valve opening degree may be controlled to be equal to the desired EGR valve opening degree value.

In this embodiment, by acquiring current operation information such as the target EGR rate, the manifold EGR rate, and the current EGR flow control amount, it is advantageous to provide an effective data basis for closed-loop control of the subsequent EGR rate. The method has the advantages that the preset EGR rate predictor is utilized to estimate the current mixing point EGR rate, so that the manifold EGR rate phase difference caused by a long loop system from an exhaust manifold to an intake manifold is eliminated, the accuracy and the reliability of the current mixing point EGR rate prediction are ensured, and the combustion stability of the system under the transient working condition is improved. On the basis, inaccuracy of system modeling and internal and external interference of the system are uniformly regarded as disturbance items of the system model, and disturbance of the preset EGR system model is estimated by using a preset first observer, so that dependence of system control precision on model precision is reduced. Meanwhile, disturbance is estimated based on the current mixing point EGR rate pre-estimation and the current EGR flow control quantity of the elimination delay, so that the accuracy of the first disturbance quantity is improved, and the accuracy of a control system is improved. And finally, obtaining a target EGR flow control quantity according to the first disturbance quantity and the target EGR rate, so that the real-time estimation and elimination of the total disturbance caused by the modeling error and the external factors are realized, and the accuracy of the target EGR flow control quantity is improved. When the opening degree of the EGR valve is controlled based on the obtained target EGR flow control quantity, the EGR rate of the system can be enabled to be closer to the target EGR rate, so that closed-loop control of the EGR rate is realized, and the accuracy and reliability of the system for controlling the EGR rate are improved.

Optionally, the current operation information further includes a total air mixture amount; estimating the EGR rate at the current mixing point based on the manifold EGR rate using a preset EGR rate estimator to obtain a predicted amount of the current mixing point EGR rate, comprising:

Inputting the total air mixing amount, the manifold EGR rate and the current EGR flow control amount into an EGR rate predictor to obtain a current mixing point EGR rate predicted value;

The EGR rate predictor satisfies:

Wherein y _P represents a current mixing point EGR rate pre-estimate; y ₁ denotes the manifold EGR rate; y _m represents a manifold EGR rate estimated value obtained by modeling the total air-fuel mixture, the current EGR flow control amount and a preset EGR system model; t represents the current time; representing the delay time estimate.

Specifically, the EGR rate estimator in this embodiment adopts a smith estimator, and the basic form of the smith estimator satisfies:

Where x _m is the state quantity of the system, u is the control quantity of the system, and y _m is the output quantity of the system.

From the above discussion, it is clear that the preset EGR system model satisfies:

Then EGR _t is selected as the system state quantity, u (i.e ) Selected as the system control amount, EGR _im is selected as the system output amount. Therefore, the estimated values of the system state quantity and the system output quantity are obtained through modeling of the total air-fuel mixture, the current EGR flow control quantity and the preset EGR system model, and the estimated values of the EGR _t and the EGR _im are obtained.

An EGR rate observer is constructed based on the basic form of the Smith predictor and a preset EGR system model, and the EGR rate predictor meets the following conditions:

Wherein y _P represents a current mixing point EGR rate pre-estimate; y ₁ denotes the manifold EGR rate measured by the virtual EGR sensor; y _m represents an estimate of system output, i.e., manifold EGR rate estimate, obtained by modeling; t represents the current time; The delay time estimated value is represented, and the delay time can be obtained through calibration or model calculation. Therefore, the EGR rate predictor can eliminate the phase difference of the manifold EGR rate based on the total air mixture, the manifold EGR rate and the current EGR flow control amount to obtain the EGR rate which is not delayed by pipeline transmission at the current mixing point, and the state quantity predicted value in the embodiment is compensated by delay on the basis of the actual measurement value of the manifold EGR rate (the virtual manifold EGR rate obtained by the virtual EGR rate sensor is taken as the actual measurement value of the manifold EGR rate in the embodiment), so that the phase is earlier than the actual measurement value, and the responsiveness of signal feedback is improved.

Optionally, based on the current EGR flow control amount and the current mixing point EGR rate pre-estimated amount, estimating disturbance of a preset EGR system model by using a preset first observer to obtain a first disturbance amount, including:

Inputting the total air mixing amount, the current EGR flow control amount and the current mixing point EGR rate pre-estimated amount into a first observer to obtain a first disturbance amount, wherein the first observer is constructed based on a preset EGR system model;

the preset EGR system model satisfies:

Wherein x ₁ represents the current mixing point EGR rate for the state quantity selected by the system; x ₂ is the state quantity of the system demand, and represents the disturbance of a preset EGR system model; y ₂ is the output quantity selected by the system; f represents disturbance of a preset EGR system model; u represents a current EGR flow control amount; h represents the derivative of f; a ₀ is a predicted value of a; b ₀ is a predicted value of b; a= -1/τ _mixing; τ _mixing represents a time constant; /(I) Representing the total air mixing amount;

the first observer satisfies:

wherein z ₁ is an estimate of x ₁; z ₂ is an estimated value of x ₂, and z ₂ represents a first disturbance variable; y ₂ is equal to the current mixing point EGR rate pre-estimate; beta ₁ represents a first tuning parameter; beta ₂ represents a second tuning parameter.

Specifically, assuming that the controlled object in this embodiment is a first-order, linear, time-varying, and perturbed system, the basic form is:

Where ax+bu represents the unknown dynamics inside the system and w represents the unknown disturbance. In this embodiment, based on the transmission model corresponding to the hybrid transmission process of the EGR system, a ₀ and b ₀,a₀≈a;b₀ ≡b can be estimated in advance, so that the model of the system can be rewritten into the following form:

From the foregoing discussion, the state space form of the preset EGR system model is:

wherein a= -1/τ _mixing; w represents a system disturbance.

It can be seen that in the preset EGR system model, w= (a-a ₀)x+(b-b₀) u.

In an embodiment, although the system model and related parameters can be obtained approximately, the model and the real situation always have errors, in this embodiment, the model and the real situation are categorized into system disturbance f, where f is the total disturbance of the system and represents all uncertainties, including inaccuracy of modeling and internal and external disturbances of the system, and then the preset EGR system model can be expressed as:

Wherein x ₁ represents the current mixing point EGR rate for the state quantity selected by the system; x ₂ is the state quantity of the system demand, and represents the disturbance of a preset EGR system model; y ₂ is the output quantity selected by the system; f represents disturbance of a preset EGR system model; u is a control quantity selected by the system and represents the current EGR flow control quantity; h represents the derivative of f; a ₀ is a predicted value of a; b ₀ is a predicted value of b; a= -1/τ _mixing; τ _mixing represents a time constant; /(I) Representing the total air mixing amount;

In an embodiment, since the EGR exhaust gas needs to pass through a long pipeline after being mixed in front of the compressor and entering the air manifold, and the delay processing is performed on the control amount input by the first observer in consideration of the system delay, the ESO extended state observer is selected based on the preset EGR system model to construct the first observer, and the first observer can be designed as follows:

wherein z ₁ is an estimate of x ₁; z ₂ is an estimated value of x ₂, and z ₂ represents a first disturbance variable; y ₂ is equal to the current mixing point EGR rate pre-estimate; beta ₁ represents a first tuning parameter; beta ₂ represents a second tuning parameter.

Because the model cannot reflect the real EGR system, the embodiment selects the current mixing point EGR rate estimated value obtained by the EGR rate estimator as the real output quantity, and the difference value between the real output quantity and the estimated output quantity is calculatedCorrecting the estimated values z ₁ and z ₂, and subtracting the model corresponding to the first observer from a preset EGR system model to obtain:

it can be further consolidated into:

Wherein e ₁ represents the deviation between the true value of the current mixing point EGR rate (i.e., the estimated value of the current mixing point EGR rate obtained by the EGR rate estimator) and the estimated value of the first observer for the current mixing point EGR rate; e ₂ represents the deviation between the true value of the preset EGR system disturbance and the estimated value of the first observer for the preset EGR system disturbance; to converge the first observer, β ₁,β₂ may be configured:

Wherein, According to the convergence principle, |a _e |= |a-lc| <0, i.e. the feature root λ(s) =s ³+(β₁-a)s+β₂ of the feature polynomial all possess a negative real part, here the first observer bandwidth ω _o is introduced to reduce the parameter adjustment effort, i.e. let λ(s) =s ³+(β₁-a)s+β₂＝(s+ω_o)², β ₁＝2ω_o+a,β₂＝ω_o ² is available.

In this embodiment, the first observer is constructed based on a preset EGR system model, and estimates the current mixing point EGR rate of the preset EGR system model and the disturbance of the preset EGR system model based on the total air-fuel mixture, the current EGR flow control amount, and the current mixing point EGR rate pre-estimation. On the basis, in the embodiment, the first observer also considers system delay in design, and delays the control quantity input by the first observer, so that the current mixing point EGR rate pre-estimation and the current mixing point EGR rate estimation are synchronous in time, and the control precision of the system is further improved.

Optionally, the current operating information further includes a manifold pressure measurement; before controlling the EGR valve opening degree based on the target EGR flow control amount, further includes:

Based on the manifold pressure measurement value, estimating disturbance of a preset air inlet pressure model by using a preset second observer to obtain a second disturbance quantity;

An EGR flow area error is determined based on the second disturbance variable.

Specifically, the manifold pressure measurement referred to in this embodiment may be measured by a physical pressure sensor. In this embodiment, the intake manifold is taken as a research object, and is regarded as an isothermal opening system, and according to the law of conservation of energy and an ideal gas state equation, an intake manifold pressure dynamic equation, namely a preset intake pressure model, can be obtained:

Wherein, Representing manifold pressure, T _im represents gas temperature, which is the intake manifold temperature since the intake manifold is isothermal in this embodiment; v _im denotes a preset intake manifold volume; /(I)Represents EGR flow (equal to the current EGR flow control amount); /(I)Representing fresh air mass flow rate, which can be measured by an air flow meter; /(I)Indicating the mass flow rate of gas into the cylinder.

In this embodiment, the second observer may be constructed based on a kalman filter, or may be constructed based on an ESO extended state observer, and preferably, in this embodiment, the construction is performed using the ESO extended state observer, and based on the design principle substantially the same as that of the first observer, the disturbance of the preset intake pressure model related to the second observer may be estimated based on the preset intake pressure model.

On this basis, for LP-EGR engine systems, the EGR flow model is calculated using orifice plate flow equations, the accuracy of which is largely dependent on differential pressure, flow coefficient and gas thermodynamic properties. However, because the front-to-back pressure ratio of the EGR valve is small, the pressure ratio function is sensitive, and the factors can cause a large deviation in the EGR rate obtained by the virtual EGR sensor. Ideally, it is considered that the deviation (i.e., the second disturbance amount) between the estimated manifold pressure value and the measured manifold pressure value (i.e., the measured manifold pressure value) obtained based on the preset intake pressure model is caused by the EGR flow deviation, and the conventional EGR flow equation may be expressed as:

Wherein, Represents EGR flow; p _us represents the EGR valve upstream pressure, and P _ds represents the EGR valve downstream pressure; t _us represents the temperature upstream of the EGR valve; c _d represents a preset flow coefficient; a _egr denotes the EGR flow area. Therefore, in the present embodiment, the manifold pressure deviation may be uniformly attributed to the occurrence of an error in the EGR flow area a _egr, and thus, the EGR flow area error may be determined based on the second disturbance variable.

In this embodiment, the disturbance of the preset intake pressure model may be estimated by using a preset second observer based on the manifold pressure measurement value, to obtain the second disturbance quantity. For the second observer, the second disturbance variable reflects mainly the deviation between the manifold pressure measurement and the manifold pressure estimate, which may be considered to be due to the deviation of the EGR flow in the virtual EGR sensor, which may in turn be considered to be due to the EGR flow area error. Therefore, based on the second disturbance quantity obtained by the second observer and the manifold pressure measurement value, the actual deviation caused by the virtual EGR rate sensor can be accurately quantized, the error of the virtual EGR sensor can be compensated based on the second disturbance quantity, and the control precision of an EGR system based on the virtual EGR sensor is further improved.

Optionally, estimating, based on the manifold pressure measurement, a disturbance of the preset intake pressure model using a preset second observer to obtain a second disturbance variable, including:

Inputting the manifold pressure measurement value into a second observer to obtain a second disturbance variable;

the second observer satisfies:

Wherein, Representing a manifold pressure estimate; /(I)Representing a manifold pressure predicted value obtained through modeling of a preset intake pressure model; p _im represents a manifold pressure measurement; /(I)Representing a second disturbance variable; beta _p1 represents a third tuning parameter; beta _p2 represents a fourth tuning parameter.

Specifically, in this embodiment, the second observer selects the ESO extended state observer, and may rewrite the preset intake air pressure model into a dynamic form:

Wherein f _p represents a disturbance of the preset intake pressure model; h _p represents the derivative of f _p.

Based on this, a second observer can be constructed that estimates the disturbance of the manifold pressure and the preset intake pressure model, the second observer satisfying:

Wherein, Representing a manifold pressure estimate; /(I)Representing a manifold pressure predicted value obtained through modeling of a preset intake pressure model; p _im represents a manifold pressure measurement; /(I)Representing a second disturbance variable; beta _p1 represents a third tuning parameter; beta _p2 represents a fourth tuning parameter.

Subtracting a dynamic form of a preset air inlet pressure model from a model corresponding to the second observer to obtain a manifold pressure estimation error model:

Wherein e _p1 represents the deviation of the manifold pressure estimate from the manifold pressure measurement; e _p2 represents the deviation of the actual disturbance of the preset intake air pressure model from the disturbance estimated value (i.e., the second disturbance quantity) of the preset intake air pressure model; beta _p1 and beta _p2 may be adjusted based on the deviation between the manifold pressure estimate and the manifold pressure measurement:

where ω _pO represents the bandwidth of the second observer.

In this way, the second observer can more accurately estimate the disturbance of the preset air inlet pressure model, and obtain a more accurate second disturbance quantity.

Optionally, the current operating information further includes EGR valve operating information including EGR valve upstream pressure, EGR valve downstream pressure, EGR valve upstream temperature, and gas temperature; determining an EGR flow area error based on the second disturbance variable, comprising:

determining an EGR flow area error based on the second disturbance quantity, the EGR valve operation information and a preset system disturbance model;

The system disturbance model satisfies:

Wherein f _p represents a disturbance of the preset intake pressure model; t _im represents the gas temperature; v _im denotes a preset intake manifold volume; Δa _egr represents EGR flow area error; p _us represents the EGR valve upstream pressure, and P _ds represents the EGR valve downstream pressure; t _us represents the temperature upstream of the EGR valve; c _d denotes a preset flow coefficient.

Specifically, based on the above discussion, the deviation between the manifold pressure measurement and the estimated manifold pressure estimated by the second observer may be considered to be due to the EGR flow area error, and then the conventional EGR flow equation may be modified to obtain the EGR flow modification model:

Wherein, Indicating the corrected EGR flow rate.

In this embodiment, the deviation between the measured manifold pressure (i.e. the measured manifold pressure) and the estimated intake manifold pressure value obtained by modeling is taken as the disturbance f, the EGR flow area required to be corrected for eliminating the disturbance f is taken as the EGR flow area error, and the system disturbance can be organized as:

Wherein f _p represents a disturbance of the preset intake pressure model; t _im represents the gas temperature; v _im denotes a preset intake manifold volume; Δa _egr represents EGR flow area error; p _us represents the EGR valve upstream pressure, and P _ds represents the EGR valve downstream pressure; t _us represents the temperature upstream of the EGR valve; c _d denotes a preset flow coefficient.

Preferably, a deviation tolerance threshold value can be set, and when the deviation between the measured manifold pressure value and the estimated manifold pressure value estimated by the second observer is larger than the deviation tolerance threshold value, the error of the EGR flow area is determined based on the second disturbance quantity, the operation information of the EGR valve and a preset system disturbance model, so that the control efficiency of the system is improved, and the calculation resources are saved.

In this embodiment, a system disturbance model is constructed by associating system disturbance with an EGR flow area error, which is favorable for ensuring accuracy and rationality of determining the EGR flow area error based on the second disturbance amount, the EGR valve operation information and a preset system disturbance model, and facilitating subsequent adjustment of the opening of the EGR valve by the system according to the EGR flow area error to compensate for deviation caused by the virtual EGR sensor.

Optionally, obtaining the target EGR flow control amount according to the first disturbance amount and the target EGR rate includes:

Inputting the first disturbance quantity, the target EGR rate and the pre-estimated EGR rate of the current mixing point into a preset controller model to obtain a target EGR flow control quantity;

The preset controller model satisfies the following conditions:

where u represents a target EGR flow control amount; x ^des represents the target EGR rate; Representing a current mixing point EGR rate pre-estimate; w represents disturbance of a preset EGR system model, which is equal to the first disturbance quantity; k _p represents the proportional gain.

Specifically, in this embodiment, a preset controller model may be constructed based on the ADRC controller, and assuming that the disturbance of the preset EGR system model may be accurately estimated by the first disturbance observer, the disturbance rejection law may be designed as:

where u represents a target EGR flow control amount; Representing a current mixing point EGR rate pre-estimate; w represents disturbance of a preset EGR system model, which is equal to the first disturbance quantity; u ₀ (t) is an imaginary control input.

Since the preset EGR system model can be expressed as:

the above equation can be converted into an integral part based on the disturbance rejection law:

For the integration step, the proportional controller may be designed to achieve the desired transient response of the closed loop system, then u ₀ (t) satisfies:

Where K _p represents a proportional gain, and K _p is equal to the bandwidth frequency ω _c;x^des of the system representing the target EGR rate.

Therefore, the preset controller model can be designed as:

In this way, the preset controller model can obtain the target EGR flow control amount based on the first disturbance amount, the target EGR rate and the current mixing point EGR rate pre-estimated amount, so as to further realize the expected transient response of the closed-loop EGR system.

Optionally, controlling the EGR valve opening based on the target EGR flow control amount includes:

And determining an EGR valve initial opening value based on the target EGR flow control amount, correcting the EGR valve initial opening value according to the EGR flow area error to obtain an EGR valve target opening value, and controlling the EGR valve opening according to the EGR valve target opening value.

Specifically, after the target EGR flow control amount is obtained, the EGR valve initial opening value may be determined based on the target EGR flow control amount in combination with the throttle equation of the EGR valve. On this basis, the EGR valve initial opening value is corrected in combination with the EGR flow area error, and the EGR valve target opening value is obtained. For example, if the EGR valve initial opening value is determined to be 20% based on the target EGR flow control amount and the EGR valve initial opening value is corrected based on the EGR flow area error to obtain the EGR valve target opening value of 25%, the EGR valve opening is controlled to be 25%.

In this embodiment, the manifold EGR rate employed during system control deviates from the true manifold EGR rate due to the accuracy of the virtual EGR rate sensor and system disturbances. The target EGR flow control amount obtained based on the method has deviation when the opening degree of the EGR valve is guided, so that the real manifold EGR rate of the system is inconsistent with the virtual EGR rate sensor, the real condition cannot be reflected by the manifold EGR rate obtained by the virtual EGR rate sensor, and the control accuracy of the system is not facilitated. In this embodiment, the second disturbance affecting the manifold pressure is estimated by the second observer, and then the EGR flow area error is determined based on the correlation between the system disturbance and the EGR flow area error (i.e., the system disturbance model), and the EGR valve initial opening value is corrected based on the EGR flow area error, so as to obtain the EGR valve target opening value, and based on the corrected EGR valve target opening value, the real manifold EGR rate can be closer to the manifold EGR rate obtained by the virtual EGR rate sensor, so that the manifold EGR rate is more real and reliable. The dependence of the control precision of the system on the model precision is reduced, and the control robustness is improved.

Illustratively, as shown in fig. 3, a control architecture corresponding to the EGR closed-loop control method will now be described in a specific embodiment:

In fig. 3, R represents a fusion module, and Q represents an intake manifold. At the intake manifold, a manifold EGR rate is output by a virtual EGR rate sensor. The EGR waste gas is mixed with fresh air and then enters an intake manifold, and then is conveyed to an engine for recycling. The execution body of the EGR closed-loop control method of the present embodiment first needs to acquire current operation information including a target EGR rate, a manifold EGR rate, a current EGR flow control amount, a total air mixture amount, and the like (not shown in fig. 3).

On the basis, the total air mixing amount, the manifold EGR rate and the current EGR flow control amount are input into an EGR rate estimator to obtain the current mixing point EGR rate pre-estimation, so that the manifold EGR rate phase difference caused by a long loop system from an exhaust manifold to an intake manifold is eliminated, the accuracy and the reliability of the current mixing point EGR rate pre-estimation are ensured, and the combustion stability of the system under transient working conditions is improved. The pre-estimated EGR rate of the current mixing point is provided for a first observer on one hand, and provided for a control module corresponding to a preset controller model on the other hand.

Firstly, inputting the total air mixing amount, the current EGR flow control amount and the current mixing point EGR rate pre-estimation into a first observer to obtain a first disturbance amount, realizing the estimation of disturbance of a preset EGR system model, being beneficial to reducing the dependence of system control precision on model precision, and on the basis, the first observer estimates the disturbance based on the current mixing point EGR rate pre-estimation and the current EGR flow control amount with elimination delay, being beneficial to further improving the accuracy of the first disturbance amount and further improving the accuracy of a control system.

Secondly, after the first observer outputs the first disturbance quantity, the target EGR rate and the pre-estimated amount of the current mixing point EGR rate are input into a preset controller model corresponding to the control module, so that the target EGR flow control quantity is obtained, the real-time estimation and elimination of the total disturbance caused by modeling errors and external factors are realized, and the accuracy of the target EGR flow control quantity is improved.

Based on the operation information such as the measured manifold pressure value and the total mixer amount, the disturbance of the preset air inlet pressure model is estimated by using a preset second observer, and the second disturbance quantity is obtained. For the second observer, the second disturbance variable reflects mainly the deviation between the manifold pressure measurement and the manifold pressure estimate, which may be considered to be due to the deviation of the EGR flow in the virtual EGR sensor, which may in turn be considered to be due to the EGR flow area error. Therefore, based on the second disturbance quantity obtained by the second observer and the manifold pressure measurement value, the actual deviation caused by the virtual EGR rate sensor can be accurately quantized, the error of the virtual EGR sensor can be compensated based on the second disturbance quantity, and the control precision of an EGR system based on the virtual EGR sensor is further improved.

After the second disturbance quantity is obtained, the second disturbance quantity is input to the threshold area self-learning module, the EGR flow area error is determined based on a system disturbance model corresponding to the threshold area self-learning module, and a reliable basis is provided for the control of the opening degree of a subsequent EGR valve.

And finally, inputting the target EGR flow control quantity and the EGR flow area error into a fusion module, determining an EGR valve initial opening value by the fusion module based on the target EGR flow control quantity, correcting the EGR valve initial opening value according to the EGR flow area error, obtaining an EGR valve target opening value, and controlling the EGR valve opening according to the EGR valve target opening value.

Therefore, the EGR closed-loop control method provided by the embodiment is based on the control framework, on one hand, the closed-loop control of the EGR rate is realized, on the other hand, the deviation of the actual value of the EGR rate caused by the virtual EGR rate sensor is compensated, so that the manifold EGR rate obtained by the actual virtual EGR rate sensor can be more attached to the actual value, the control precision of the system does not need to depend on the model precision, the elimination of disturbance of the system is realized, and the control precision of the system is improved in all directions.

As shown in fig. 4, a further embodiment of the present invention provides an EGR closed-loop control device including:

The system comprises an acquisition module, a control module and a control module, wherein the acquisition module is used for acquiring current operation information, and the current operation information comprises a target EGR rate, a manifold EGR rate and a current EGR flow control quantity;

The EGR rate estimating module is used for estimating the current mixing point EGR rate by utilizing a preset EGR rate estimator based on the manifold EGR rate to obtain a current mixing point EGR rate estimated value;

The first observation module is used for estimating disturbance of a preset EGR system model by using a preset first observer based on the current EGR flow control quantity and the current mixing point EGR rate preset quantity to obtain a first disturbance quantity;

And the control module is used for obtaining a target EGR flow control amount according to the first disturbance amount, the current mixing point EGR rate pre-estimation and the target EGR rate and controlling the opening of the EGR valve based on the target EGR flow control amount.

The technical effects that the EGR closed-loop control device and the EGR closed-loop control method provided in this embodiment can produce are basically the same, and are not described here again.

As shown in fig. 5, a further embodiment of the present invention also provides a vehicle including a memory for storing a computer program and a processor for implementing the EGR closed-loop control method as described above when the computer program is executed.

The technical effects that the vehicle and the EGR closed-loop control method provided in this embodiment can produce are basically the same, and are not described here again.

The vehicle may include an electronic device, which may be a server or a client of the present invention, which will now be described as an example of a hardware device that may be applied to aspects of the present invention. Electronic devices are intended to represent various forms of digital electronic computer devices, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processing, cellular telephones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions, are meant to be exemplary only, and are not meant to limit implementations of the inventions described and/or claimed herein.

The electronic device includes a computing unit that can perform various appropriate actions and processes according to a computer program stored in a Read Only Memory (ROM) or a computer program loaded from a storage unit into a Random Access Memory (RAM). In the RAM, various programs and data required for the operation of the device may also be stored. The computing unit, ROM and RAM are connected to each other by a bus. An input/output (I/O) interface is also connected to the bus.

The computer system may include a client and a server. The client and server are typically remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

Those skilled in the art will appreciate that implementing all or part of the above-described methods in accordance with the embodiments may be accomplished by way of a computer program stored on a computer readable storage medium, which when executed may comprise the steps of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a random-access Memory (Random Access Memory, RAM), or the like. In the present application, the units described as separate units may or may not be physically separate, and units displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiment of the present application. In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

Although the invention is disclosed above, the scope of the invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and these changes and modifications will fall within the scope of the invention.

Claims (10)

1. An EGR closed-loop control method, characterized by comprising:

Acquiring current operation information, wherein the current operation information comprises a target EGR rate, a manifold EGR rate and a current EGR flow control amount;

Estimating the current mixing point EGR rate by using a preset EGR rate estimator based on the manifold EGR rate to obtain a current mixing point EGR rate estimated value;

Estimating disturbance of a preset EGR system model by using a preset first observer based on the current EGR flow control quantity and the current mixing point EGR rate preset quantity to obtain a first disturbance quantity;

And obtaining a target EGR flow control amount according to the first disturbance amount and the target EGR rate, and controlling the opening of an EGR valve based on the target EGR flow control amount.

2. The EGR closed-loop control method according to claim 1, characterized in that the current operation information further includes a total air-fuel mixture amount; the estimating, based on the manifold EGR rate, the EGR rate at the current mixing point by using a preset EGR rate estimator to obtain a predicted amount of the EGR rate at the current mixing point, including:

inputting the total air mixing amount, the manifold EGR rate and the current EGR flow control amount into the EGR rate predictor to obtain the current mixing point EGR rate pre-estimation;

the EGR rate predictor satisfies:

Wherein y _P represents the current mixing point EGR rate pre-estimate; y ₁ represents the manifold EGR rate; y _m represents a manifold EGR rate estimated value obtained by modeling the total air-fuel mixture, the current EGR flow control amount and the preset EGR system model; t represents the current time; representing the delay time estimate.

3. The EGR closed-loop control method according to claim 2, wherein the estimating, based on the current EGR flow control amount and the current mixing point EGR rate pre-estimate, a disturbance of a preset EGR system model using a preset first observer, to obtain a first disturbance amount includes:

Inputting the total air mixing amount, the current EGR flow control amount and the current mixing point EGR rate pre-estimated amount into the first observer to obtain the first disturbance amount, wherein the first observer is constructed based on the preset EGR system model;

The preset EGR system model satisfies:

Wherein x ₁ is a state quantity selected by the system and represents the current mixing point EGR rate; x ₂ is a state quantity selected by the system and represents disturbance of the preset EGR system model; y ₂ is the output quantity selected by the system; f represents disturbance of the preset EGR system model; u is a control quantity selected by a system and represents the current EGR flow control quantity; h represents the derivative of f; a ₀ is a predicted value of a; b ₀ is a predicted value of b; a= -1/τ _mixing; τ _mixing represents a time constant; /(I) Representing the total air mixture amount;

the first observer satisfies:

Wherein z ₁ is an estimate of x ₁; z ₂ is an estimated value of x ₂, and z ₂ represents the first disturbance variable; y ₂ is equal to the current mixing point EGR rate pre-estimate; beta ₁ represents a first tuning parameter; beta ₂ represents a second tuning parameter.

4. The EGR closed-loop control method of claim 2, wherein the current operating information further includes a manifold pressure measurement; before the controlling the EGR valve opening based on the target EGR flow control amount, further includes:

Based on the manifold pressure measurement value, estimating disturbance of a preset air inlet pressure model by using a preset second observer to obtain a second disturbance quantity;

An EGR flow area error is determined based on the second disturbance variable.

5. The EGR closed-loop control method according to claim 4, wherein estimating disturbance of a preset intake pressure model with a preset second observer based on the manifold pressure measurement value, to obtain a second disturbance quantity, includes:

Inputting the manifold pressure measurement into the second observer to obtain the second disturbance variable;

The second observer satisfies:

Wherein, Representing the manifold pressure estimate; /(I)Representing a manifold pressure predicted value obtained through modeling of the preset intake pressure model; p _im represents the manifold pressure measurement; /(I)Representing the second disturbance variable; beta _p1 represents a third tuning parameter; beta _p2 represents a fourth tuning parameter.

6. The EGR closed-loop control method of claim 4, wherein the current operation information further includes EGR valve operation information including EGR valve upstream pressure, EGR valve downstream pressure, EGR valve upstream temperature, and gas temperature; the determining an EGR flow area error based on the second disturbance variable includes:

Determining the EGR flow area error based on the second disturbance quantity, the EGR valve operation information and a preset system disturbance model;

The system disturbance model satisfies the following conditions:

Wherein f _p represents a disturbance of the preset intake pressure model; t _im represents the gas temperature; v _im denotes a preset intake manifold volume; Δa _egr represents the EGR flow area error; p _us represents the EGR valve upstream pressure, and P _ds represents the EGR valve downstream pressure; t _us represents the temperature upstream of the EGR valve; c _d denotes a preset flow coefficient.

7. The EGR closed-loop control method according to claim 6, wherein the obtaining a target EGR flow control amount from the first disturbance amount and the target EGR rate includes:

inputting the first disturbance quantity, the target EGR rate and the pre-estimated current mixing point EGR rate into a preset controller model to obtain the target EGR flow control quantity;

the preset controller model satisfies:

Wherein u represents the target EGR flow control amount; x ^des represents the target EGR rate; Representing the current mixing point EGR rate pre-estimate; w represents disturbance of the preset EGR system model, which is equal to the first disturbance quantity; k _R represents the proportional gain.

8. The EGR closed-loop control method according to claim 6, characterized in that the controlling the EGR valve opening based on the target EGR flow control amount includes:

and determining an EGR valve initial opening value based on the target EGR flow control amount, correcting the EGR valve initial opening value according to the EGR flow area error to obtain an EGR valve target opening value, and controlling the EGR valve opening according to the EGR valve target opening value.

9. An EGR closed-loop control apparatus, characterized by comprising:

an acquisition module for acquiring current operation information including a target EGR rate, a manifold EGR rate, and a current EGR flow control amount;

The EGR rate estimating module is used for estimating the current mixing point EGR rate by using a preset EGR rate estimator based on the manifold EGR rate to obtain a current mixing point EGR rate estimated value;

The first observation module is used for estimating disturbance of a preset EGR system model by using a preset first observer based on the current EGR flow control quantity and the current mixing point EGR rate preset quantity to obtain a first disturbance quantity;

And the control module is used for obtaining a target EGR flow control amount according to the first disturbance amount, the current mixing point EGR rate pre-estimation amount and the target EGR rate and controlling the opening of the EGR valve based on the target EGR flow control amount.

10. A vehicle comprising a memory for storing a computer program and a processor for implementing the EGR closed-loop control method according to any one of claims 1 to 8 when the computer program is executed.