阅读说明：本技术 一种egr阀控制方法、控制装置及计算机可读存储介质 (EGR valve control method, control device and computer readable storage medium ) 是由 王云鹏 李超 邓柯 詹坤 刘海报 王晓鹏 于 2020-12-08 设计创作，主要内容包括：本发明公开了一种EGR阀控制方法、控制装置及计算机可读存储介质,其中,所述方法包括：获取发动机的总进气量；获取发动机的EGR阀的进口与出口的压力比值,并根据压力比值计算发动机的当前EGR废气流量和当前EGR率；获取目标EGR率,根据总进气量和目标EGR率计算目标新鲜进气量；根据目标新鲜进气量调节EGR阀的开度。本发明通过获取发动机的总进气量,并通过EGR阀前后的压比计算出当前EGR废气流量,再根据发动机总进气量和目标EGR率,实时计算目标新鲜进气量,进而通过调整EGR开度,使实际新鲜进气量达到目标新鲜进气,从而使得当前EGR率达到目标EGR率。(The invention discloses an EGR valve control method, a control device and a computer readable storage medium, wherein the method comprises the following steps: acquiring the total air inflow of the engine; acquiring a pressure ratio of an inlet and an outlet of an EGR valve of the engine, and calculating the current EGR exhaust gas flow and the current EGR rate of the engine according to the pressure ratio; obtaining a target EGR rate, and calculating a target fresh air inflow according to the total air inflow and the target EGR rate; the opening degree of the EGR valve is adjusted according to the target fresh intake air amount. According to the invention, the total air inflow of the engine is obtained, the current EGR waste gas flow is calculated through the pressure ratio of the front and the back of the EGR valve, the target fresh air inflow is calculated in real time according to the total air inflow of the engine and the target EGR rate, and the actual fresh air inflow reaches the target fresh air inflow by adjusting the EGR opening degree, so that the current EGR rate reaches the target EGR rate.)

1. An EGR valve control method, characterized by comprising the steps of:

acquiring the total air inflow of the engine;

acquiring a pressure ratio of an inlet and an outlet of an EGR valve of the engine, and calculating the current EGR exhaust gas flow and the current EGR rate of the engine according to the pressure ratio;

obtaining a target EGR rate, and calculating a target fresh air inflow according to the total air inflow and the target EGR rate;

and adjusting the opening degree of the EGR valve according to the target fresh air intake quantity.

2. The EGR valve control method according to claim 1, wherein the obtaining of the total intake air amount of the engine previously includes:

the target EGR rate is set according to the input EGR rate demand value.

3. The EGR valve control method according to claim 1, wherein the obtaining of the total intake air amount of the engine includes:

acquiring a current intake air temperature value of an intake manifold of the engine through a temperature sensor;

acquiring a current intake pressure value of an intake manifold of the engine through a first pressure sensor;

and calculating the total air inflow of the engine according to the current air inflow temperature value, the current air inflow pressure value and a first preset algorithm.

4. The EGR valve control method of claim 1, wherein said obtaining a pressure ratio of an inlet to an outlet of an EGR valve of the engine, and calculating a current EGR exhaust gas flow rate and a current EGR rate of the engine based on the pressure ratio comprises:

acquiring sound velocity flow under a standard atmospheric environment;

acquiring the pressure ratio of an inlet and an outlet of an EGR valve of the engine through a second pressure sensor and a third pressure sensor;

calculating the current EGR exhaust gas flow of the engine according to the pressure ratio, the sonic flow and a second preset algorithm;

and determining the current EGR rate according to the current EGR exhaust gas flow and the total intake air amount.

5. The EGR valve control method of claim 4, wherein said calculating a current EGR exhaust gas flow rate for the engine based on the pressure ratio, the sonic flow rate, and a second predetermined algorithm comprises:

acquiring a density correction parameter of the exhaust gas at an inlet of an EGR valve of the engine;

correcting the density of the waste gas at the inlet of the EGR valve according to the density correction parameter to obtain the corrected density of the waste gas;

acquiring a correction parameter of the pressure ratio;

correcting the pressure ratio according to the correction parameter of the pressure ratio to obtain a corrected pressure ratio;

and calculating the current EGR exhaust gas flow according to the corrected exhaust gas density, the corrected pressure ratio and the sonic flow.

6. The EGR valve control method according to claim 1, wherein said obtaining a target EGR rate, and calculating a target fresh intake air amount from the total intake air amount and the target EGR rate, includes:

acquiring the target EGR rate;

determining a corresponding target EGR exhaust gas flow according to the target EGR rate and the total air intake quantity;

and calculating the target fresh air inflow according to the total air inflow and the target EGR exhaust gas flow.

7. The EGR valve control method according to claim 1, wherein said adjusting the opening degree of the EGR valve in accordance with the target fresh intake air amount includes:

determining a target opening degree of the EGR valve according to the target fresh air inflow amount;

and controlling the EGR valve to adjust from the current opening degree to the target opening degree so that the current EGR rate reaches the target EGR rate.

8. The EGR valve control method of claim 1, further comprising:

monitoring the air inflow of an air intake manifold of the engine in real time, and comparing the air inflow of the air intake manifold with the target fresh air inflow to obtain a deviation value;

and correcting the opening degree of the EGR valve according to the deviation value.

9. An EGR valve control apparatus comprising a processor and a memory connected to the processor, the memory storing an EGR valve control program, the EGR valve control program being executed by the processor to implement the EGR valve control method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that the memory stores an EGR valve control program which is executed by the processor for implementing an EGR valve control method according to any one of claims 1 to 8.

Technical Field

The invention relates to the application field of an EGR valve control device, in particular to an EGR valve control method, an EGR valve control device and a computer readable storage medium.

Background

EGR is an abbreviation for Exhaust Gas Re-circulation, i.e., Exhaust Gas recirculation. Exhaust gas recirculation refers to the recirculation of a portion of the exhaust gases from the engine back into the intake manifold and back into the cylinders along with fresh mixture. Since exhaust gas contains a large amount of polyatomic gas such as CO2, while gas such as CO2 cannot be combusted, it absorbs a large amount of heat due to its high specific heat capacity, and lowers the maximum combustion temperature of the air-fuel mixture in the cylinder, thereby reducing the amount of NOx generated. At present, the technology is generally used by diesel vehicles to achieve the aim of reducing NOx emission.

At present, in an implementation mode of the EGR rate, a closed-loop control mode based on an air flow meter is more adopted, and the closed-loop control mode needs to set an air quantity required value according to the rotating speed and the load of an engine and then controls the opening degree of an EGR valve to enable an actual measured value of the air quantity to be consistent with the required value; however, such closed-loop control fails to accurately control the EGR rate, resulting in poor consistency of gas emissions.

Accordingly, the prior art is yet to be improved and developed.

Disclosure of Invention

The present invention provides an EGR valve control method, a control device and a computer readable storage medium to solve the problem of poor consistency of gas emission in the conventional EGR valve control method.

The technical scheme adopted by the invention for solving the technical problem is as follows:

in a first aspect, the present invention provides an EGR valve control method, wherein the EGR valve control method comprises the steps of:

acquiring the total air inflow of the engine;

acquiring a pressure ratio of an inlet and an outlet of an EGR valve of the engine, and calculating the current EGR exhaust gas flow and the current EGR rate of the engine according to the pressure ratio;

obtaining a target EGR rate, and calculating a target fresh air inflow according to the total air inflow and the target EGR rate;

and adjusting the opening degree of the EGR valve according to the target fresh air intake quantity.

In one embodiment, the obtaining of the total intake air amount of the engine previously includes:

the target EGR rate is set according to the input EGR rate demand value.

In one embodiment, the obtaining of the total intake air amount of the engine specifically includes:

acquiring a current intake air temperature value of an intake manifold of the engine through a temperature sensor;

acquiring a current intake pressure value of an intake manifold of the engine through a first pressure sensor;

and calculating the total air inflow of the engine according to the current air inflow temperature value, the current air inflow pressure value and a first preset algorithm.

In one embodiment, the obtaining a pressure ratio of an inlet to an outlet of an EGR valve of the engine and calculating a current EGR exhaust gas flow and a current EGR rate of the engine according to the pressure ratio specifically includes:

acquiring sound velocity flow under a standard atmospheric environment;

acquiring the pressure ratio of an inlet and an outlet of an EGR valve of the engine through a second pressure sensor and a third pressure sensor;

calculating the current EGR exhaust gas flow of the engine according to the pressure ratio, the sonic flow and a second preset algorithm;

and determining the current EGR rate according to the current EGR exhaust gas flow and the total intake air amount.

In one embodiment, the calculating the current EGR exhaust gas flow rate of the engine according to the pressure ratio, the sonic flow rate and a second preset algorithm specifically comprises:

acquiring a density correction parameter of the exhaust gas at an inlet of an EGR valve of the engine;

correcting the density of the waste gas at the inlet of the EGR valve according to the density correction parameter to obtain the corrected density of the waste gas;

acquiring a correction parameter of the pressure ratio;

correcting the pressure ratio according to the correction parameter of the pressure ratio to obtain a corrected pressure ratio;

and calculating the current EGR exhaust gas flow according to the corrected exhaust gas density, the corrected pressure ratio and the sonic flow.

In one embodiment, the obtaining the target EGR rate and calculating the target fresh intake air amount according to the total intake air amount and the target EGR rate specifically include:

acquiring the target EGR rate;

determining a corresponding target EGR exhaust gas flow according to the target EGR rate and the total air intake quantity;

and calculating the target fresh air inflow according to the total air inflow and the target EGR exhaust gas flow.

In one embodiment, the adjusting the opening degree of the EGR valve according to the target fresh intake air amount specifically includes:

determining a target opening degree of the EGR valve according to the target fresh air inflow amount;

and controlling the EGR valve to adjust from the current opening degree to the target opening degree so that the current EGR rate reaches the target EGR rate.

In one embodiment, the EGR valve control method further comprises:

monitoring the air inflow of an air intake manifold of the engine in real time, and comparing the air inflow of the air intake manifold with the target fresh air inflow to obtain a deviation value;

and correcting the opening degree of the EGR valve according to the deviation value.

In a second aspect, the present invention further provides an EGR valve control apparatus, comprising a processor and a memory connected to the processor, wherein the memory stores an EGR valve control program, and the EGR valve control program is executed by the processor to implement the EGR valve control method according to the first aspect.

In a third aspect, the present invention also provides a computer-readable storage medium, characterized in that the memory stores an EGR valve control program, which is executed by the processor to implement the EGR valve control method according to the first aspect.

The invention adopts the technical scheme and has the following effects:

according to the invention, the total air inflow of the engine is obtained, the current EGR waste gas flow is calculated through the pressure ratio of the front and the back of the EGR valve, the target fresh air inflow is calculated in real time according to the total air inflow of the engine and the target EGR rate, and the actual fresh air inflow reaches the target fresh air inflow by adjusting the EGR opening degree, so that the current EGR rate reaches the target EGR rate.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a flow chart of an EGR valve control method in one implementation of the present invention.

FIG. 2 is a schematic diagram of an EGR valve control circuit and control thereof in one implementation of the present invention.

Fig. 3 is a functional schematic diagram of an EGR valve control apparatus in an implementation of the present invention.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the existing EGR control mode, a closed-loop control mode based on an air flow meter is adopted, the closed-loop control mode needs to set an air quantity required value according to the rotating speed and the load of an engine, and then the opening degree of an EGR valve is controlled to enable an actually measured value of the air quantity to be consistent with the required value; however, such closed-loop control fails to accurately control the EGR rate, resulting in poor consistency of gas emissions.

The inventor proposes an EGR valve control method applied to an EGR valve control device, which may be an ECU control device of an automobile, in view of the above problems, and the main control principle thereof is as follows: the total air inflow of the engine is calculated according to the current air inlet temperature and pressure, the current EGR exhaust gas flow is calculated according to the pressure ratio and the sonic flow before and after the EGR valve, the demand of the fresh air inflow is calculated in real time according to the total air inflow of the engine and the demand of the EGR rate, and the actual fresh air inflow is consistent with the demand by adjusting the EGR opening degree, so that the accuracy of the EGR rate is ensured.

Exemplary method

As shown in fig. 1, an embodiment of the present invention provides an EGR valve control method applied to a vehicle control apparatus, that is, a vehicle ECU apparatus, the EGR valve control method including the steps of:

in step S100, the total intake air amount of the engine is acquired.

In the present embodiment, in the process of controlling the EGR rate, it is necessary to obtain the total intake air amount of the engine, which is the flow rate of gas flowing into the cylinder from the engine intake manifold, and which is equal to the sum of the EGR exhaust gas flow rate plus the fresh intake air amount; therefore, when the EGR rate is controlled, the total air intake demand of the engine can be determined by acquiring the total air intake quantity of the engine, then the EGR exhaust gas demand is determined according to the EGR rate, and finally the fresh air demand of the engine is determined according to the total air intake demand and the EGR exhaust gas demand; further, by controlling the amount of fresh air required by the engine, the EGR valve can be controlled within the target range.

Specifically, before controlling the EGR rate, i.e., before the engine is started, it is also necessary to set a target EGR rate according to the input EGR rate demand value; wherein the target EGR rate is the exhaust gas recovery rate needing to be controlled; when the target EGR rate is set, the EGR rate demand value can be flushed into the ECU through a software program; wherein different rotation speeds correspond to different EGR rate demand values, and the target EGR rate is changed along with the change of the rotation speed of the engine; during the engine rotation, the ECU may control an EGR valve of the engine according to the target EGR rate so that the current EGR rate reaches the target EGR rate.

That is, in an implementation manner of the present embodiment, the step 100 includes the following steps before:

step 001, setting the target EGR rate according to the input EGR rate demand value.

In the embodiment, when the engine is started, the ECU acquires data collected by each sensor, and then calculates and analyzes the data to obtain the total air inflow of the engine; when data required by an ECU (electronic control Unit) is acquired, a current intake temperature value of an intake manifold of the engine can be acquired through a temperature sensor, and a current intake pressure value of the intake manifold of the engine is acquired through a first pressure sensor; then, substituting the obtained current intake temperature value and the current intake pressure value into a first preset algorithm, and calculating the total intake air quantity of the engine; the first preset algorithm is a speed density algorithm, and the specific calculation mode is as follows:

wherein:

m_totalthe total air intake (kg/s) of the engine;

η_volcharging efficiency for the engine;

P_intakeis the engine intake manifold absolute pressure (hpa);

V_cylto send outSingle cylinder volume (m) of engine₃)；

N_engEngine speed (rpm);

num_cylthe number of cylinders;

T_intakeengine intake manifold absolute temperature (K);

R_airgas constant (287.05J/kg. K);

i number of cycles for single cylinder work (2 cycles for four stroke machine).

In the speed density algorithm, under the condition that the engine model is determined, the engine inflation efficiency, the engine single-cylinder volume, the number of cylinders and the number of single-cylinder work-doing cycles can all obtain corresponding data according to the engine model, and the engine rotating speed can be obtained according to a rotating speed meter.

That is, in an implementation manner of this embodiment, the step 100 specifically includes the following steps:

step 101, acquiring a current intake air temperature value of an intake manifold of the engine through a temperature sensor;

102, acquiring a current intake pressure value of an intake manifold of the engine through a first pressure sensor;

and 103, calculating the total air inflow of the engine according to the current air inflow temperature value, the current air inflow pressure value and a first preset algorithm.

The method comprises the steps of determining the total air inflow of the engine by acquiring the air inlet temperature and the air inlet pressure of an air inlet manifold of the engine, and calculating the fresh air flow required by the engine according to the total air inflow of the engine and the EGR waste gas demand.

In one implementation of the embodiment of the invention, as shown in fig. 1, the EGR valve control method further comprises the steps of:

and step S200, acquiring a pressure ratio of an inlet and an outlet of an EGR valve of the engine, and calculating the current EGR exhaust gas flow and the current EGR rate of the engine according to the pressure ratio.

In this embodiment, after the total intake air amount of the engine is obtained through calculation, the current EGR exhaust gas flow rate of the engine needs to be obtained, so as to determine the current EGR rate according to the current EGR exhaust gas flow rate; when the current EGR exhaust gas flow is obtained, the sonic flow of an EGR valve needs to be obtained; the sound velocity flow is the sound velocity flow under the standard atmospheric pressure environment, and the atmospheric pressure value under the standard atmospheric pressure environment is 101 Kpa; meanwhile, the ECU acquires the inlet pressure value of the EGR valve of the engine through the second pressure sensor, acquires the outlet pressure value of the EGR valve of the engine through the third pressure sensor, and calculates the pressure ratio of the inlet and the outlet of the EGR valve of the engine according to the inlet pressure value and the outlet pressure value.

After the sound velocity flow and the pressure ratio are determined, substituting the sound velocity flow and the pressure ratio into a second preset algorithm to obtain the current EGR exhaust gas flow of the engine, and further determining the current EGR rate according to the current EGR exhaust gas flow and the total air inflow; the second preset algorithm is a density-pressure ratio algorithm, and the density-pressure ratio algorithm is used for multiplying the sonic flow, the corrected inlet air density and the corrected pressure ratio to obtain the actual flow of the current EGR waste gas.

That is, in an implementation manner of this embodiment, the step S200 specifically includes the following steps:

step S201, obtaining sound velocity flow under a standard atmospheric environment;

step S202, acquiring a pressure ratio of an inlet and an outlet of an EGR valve of the engine through a second pressure sensor and a third pressure sensor;

step S203, calculating the current EGR waste gas flow of the engine according to the pressure ratio, the sonic flow and a second preset algorithm;

and step S204, determining the current EGR rate according to the current EGR exhaust gas flow and the total intake air amount.

In this embodiment, the EGR valve can be regarded as a standard throttle valve, and the air flow model at the front end and the rear end of the EGR valve can adopt a one-dimensional isentropic stable flow model and is calculated by using the model; the gas can be regarded as ideal gas, the constant value ratio is adopted for hot melting, the flow is reversible, and the gas flow is regarded as an adiabatic process; and substituting corresponding data into a second preset algorithm for calculation according to the adopted model to obtain the current EGR exhaust gas flow, wherein the specific calculation mode is as follows:

wherein m is_{sonic_std}The flow rate is the sound velocity flow rate (kg/s) under the standard environment;

P_inis EGR valve inlet pressure;

P_stdthe standard atmospheric pressure is 101.325 kpa;

T_inis EGR valve inlet temperature;

T_stdat a standard temperature of 20 ℃;

Pr_egrthe pressure ratio of two ends of the EGR valve;

Pr_sonicis the critical pressure ratio;

k is the adiabatic index and the two atom molecule is 1.41.

It is understood that, in the above density-pressure ratio algorithm, the actual EGR exhaust gas flow rate is (sonic flow rate) x (inlet density correction) x (pressure ratio correction with physical properties); therefore, during actual calculation, a density correction parameter of the exhaust gas at the inlet of the EGR valve of the engine can be obtained, and the density of the exhaust gas at the inlet of the EGR valve is corrected by the density correction parameter, so that the corrected exhaust gas density is obtained; then, acquiring a correction parameter of the pressure ratio, and correcting the pressure ratio by using the correction parameter to obtain a corrected pressure ratio; and finally, multiplying the corrected exhaust gas density, the corrected pressure ratio and the sonic flow to obtain the current EGR exhaust gas flow of the engine.

In practical application, when the EGR exhaust gas flow is calculated, only the sonic flow needs to be calibrated, the sonic flow is only related to the opening area, and the opening area and the position of the EGR valve are in one-to-one correspondence, so that the EGR valve position-sonic flow parameter needs to be calibrated finally.

That is, in an implementation manner of this embodiment, the step S203 specifically includes the following steps:

step S2031, obtaining density correction parameters of EGR valve inlet exhaust gas of the engine;

step S2032, correcting the density of the EGR valve inlet exhaust gas according to the density correction parameter to obtain the corrected exhaust gas density;

step S2033, obtaining a correction parameter of the pressure ratio;

step S2034, correcting the pressure ratio according to the correction parameter of the pressure ratio to obtain a corrected pressure ratio;

step S2035, calculating the current EGR exhaust gas flow rate from the corrected exhaust gas density, the corrected pressure ratio, and the sonic flow rate.

According to the method, the current EGR rate and the opening degree of the EGR valve can be determined by obtaining the current EGR exhaust gas flow of the engine, so that the EGR valve is controlled to rotate from the current opening degree to the target opening degree according to the target EGR valve, and the adjusted EGR rate is consistent with the target EGR rate.

In one implementation of the embodiment of the invention, as shown in fig. 1, the EGR valve control method further comprises the steps of:

and step S300, acquiring a target EGR rate, and calculating a target fresh air inflow according to the total air inflow and the target EGR rate.

In the embodiment, after the current EGR exhaust gas flow of the engine is determined, the ECU acquires a target EGR rate, and then calculates a target fresh air inflow according to the total air inflow and the target EGR rate; because the total air inflow of the engine is fixed, the corresponding target EGR exhaust gas flow can be determined according to the target EGR rate and the total air inflow; and the fresh air intake amount is equal to the total air intake amount-EGR exhaust gas flow, so the target fresh air intake amount can be calculated according to the total air intake amount and the target EGR exhaust gas flow.

That is, in an implementation manner of this embodiment, the step S300 specifically includes the following steps:

step S301, acquiring the target EGR rate;

step S302, determining a corresponding target EGR exhaust gas flow according to the target EGR rate and the total intake air amount;

and step S303, calculating the target fresh air inflow according to the total air inflow and the target EGR exhaust gas flow.

According to the method, the target EGR rate is obtained, the EGR waste gas demand (namely the target EGR waste gas flow) when the target EGR rate is reached can be determined, under the condition that the total air intake amount is not changed, the demand of the fresh air intake amount (the target fresh air intake amount) can be determined according to the EGR waste gas demand, and the control of the EGR rate can be realized by adjusting the fresh air intake amount.

In one implementation of the embodiment of the invention, as shown in fig. 1, the EGR valve control method further comprises the steps of:

and step S400, adjusting the opening degree of the EGR valve according to the target fresh air intake quantity.

In this embodiment, after the target fresh air intake amount is determined, the opening degree of the EGR valve may be adjusted according to the target fresh air intake amount, so that the current EGR rate reaches the target EGR rate; in actual control, determining a target opening degree of an EGR valve corresponding to the target fresh air inflow amount by taking the target fresh air inflow amount as a reference; then, the EGR valve is controlled by the PID controller to adjust the EGR valve from the current opening degree to the target opening degree, so that the current EGR rate reaches the target EGR rate.

The specific control logic is shown in fig. 2:

the EGR control system directly takes the target EGR rate as the target parameter when in control and comprises two closed-loop control loops. The internal circuit is a closed-loop circuit for controlling and feeding back the position of the EGR valve, and the EGR actuator (i.e., the PID controller shown in fig. 2) performs closed-loop control of the EGR valve according to a desired target position (i.e., a target opening degree).

And the external circuit comprises: pre-control and closed-loop control. The pre-control is to calculate the total air quantity according to a speed density method, and multiply the total air quantity with the EGR rate demand quantity to obtain an EGR flow demand (namely the target EGR exhaust gas flow); then, correcting to obtain sonic flow according to the intake air density and the pressure ratio of the front end and the rear end of the EGR valve; and finally, obtaining the required position of the EGR valve (namely the target opening degree of the EGR valve) by back checking the corresponding relation of the position-flow curve, and enabling the control system to respond more quickly by pre-controlling the position of the EGR valve.

The closed-loop control of the external loop is the closed-loop control of the flow of the EGR valve, and an EGR rate demand (namely a target EGR rate) is obtained according to the engine speed and IMEP (namely the average effective pressure); then, calculating according to the total intake air amount and the EGR rate demand to obtain a fresh air amount demand (namely a target fresh intake air amount), and comparing the fresh air amount demand with a measured value of an air flow sensor to obtain a fresh intake air amount deviation; finally, adjustments are made to the EGR controller to correct the EGR valve position for the deviation. The control mode considers the influence of the inlet air temperature and pressure on the air inlet quantity of the engine, can calibrate the required fresh air inlet quantity in real time, ensures the control precision of the EGR valve and ensures the discharge stability.

That is, in an implementation manner of this embodiment, the step S400 specifically includes the following steps:

step S401, determining a target opening degree of the EGR valve according to the target fresh air intake quantity;

and S402, controlling the EGR valve to adjust from the current opening degree to the target opening degree so that the current EGR rate reaches the target EGR rate.

Step S403, monitoring the air intake manifold air inflow of the engine in real time, and comparing the air intake manifold air inflow with the target fresh air inflow to obtain a deviation value;

and S404, correcting the opening degree of the EGR valve according to the deviation value.

Therefore, the invention calculates the total air inflow of the engine according to the current air inlet temperature and pressure, calculates the current EGR waste gas flow through the pressure ratio and sonic flow before and after the EGR valve, calculates the demand quantity of the fresh air inflow in real time according to the total air inflow of the engine and the demand value of the EGR rate, and further ensures the accuracy of the EGR rate by adjusting the EGR opening degree to ensure that the actual fresh air inflow is consistent with the demand quantity.

Exemplary device

Based on the above embodiment, the present invention also provides an EGR valve control apparatus, a schematic block diagram of which may be shown in fig. 3.

The EGR valve control device comprises a processor (ECU), a memory, a network interface and a display screen which are connected through a system bus; wherein the processor of the EGR valve control means is adapted to provide calculation and control capabilities; the memory of the EGR valve control device comprises a nonvolatile storage medium and an internal memory; the non-volatile storage medium stores an operating system and a computer program; the internal memory provides an environment for the operation of an operating system and a computer program in the nonvolatile storage medium; the network interface of the EGR valve control device is used for communicating with an external EGR valve control device through network connection.

The computer program when executed by a processor to implement an EGR valve control method; the display screen of the EGR valve control device can be a liquid crystal display screen or an electronic ink display screen.

It will be understood by those skilled in the art that the schematic block diagram shown in fig. 3 is only a block diagram of a partial structure related to the inventive concept and does not constitute a limitation of the EGR valve control apparatus to which the inventive concept is applied, and a specific EGR valve control apparatus may include more or less components than those shown in the drawings, or combine some components, or have a different arrangement of components.

In one embodiment, an EGR valve control apparatus is provided, comprising a processor and a memory connected to the processor, the memory storing an EGR valve control program, the EGR valve control program being executable by the processor for implementing the EGR valve control method as described above.

In one embodiment, a computer readable storage medium is provided, wherein the memory stores an EGR valve control program that when executed by the processor is for implementing an EGR valve control method as described above.

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, databases, or other media used in embodiments provided herein may include non-volatile and/or volatile memory.

In summary, the present invention discloses an EGR valve control method, an EGR valve control device, and a computer readable storage medium, wherein the method comprises: acquiring the total air inflow of the engine; acquiring a pressure ratio of an inlet and an outlet of an EGR valve of the engine, and calculating the current EGR exhaust gas flow and the current EGR rate of the engine according to the pressure ratio; obtaining a target EGR rate, and calculating a target fresh air inflow according to the total air inflow and the target EGR rate; and adjusting the opening degree of the EGR valve according to the target fresh air intake quantity. According to the invention, the total air inflow of the engine is obtained, the current EGR waste gas flow is calculated through the pressure ratio of the front and the back of the EGR valve, the target fresh air inflow is calculated in real time according to the total air inflow of the engine and the target EGR rate, and the actual fresh air inflow reaches the target fresh air inflow by adjusting the EGR opening degree, so that the current EGR rate reaches the target EGR rate.

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.