阅读说明：本技术 发动机的空气系统控制方法及装置、空气系统 (Air system control method and device of engine and air system ) 是由 卫阳飞 徐帅卿 赵进超 赵晓 于 2020-12-08 设计创作，主要内容包括：本发明公开了一种发动机的空气系统控制方法,空气系统中的控制变量有节气门开度、增压器开度和EGR阀开度,被控变量有空气流量、增压压力和EGR流量,包括：获取每个控制变量对各个被控变量影响的传递函数；根据传递函数获得节气门、增压器、EGR阀之间的解耦传递函数；根据解耦传递函数产生用于控制节气门的信号、用于控制增压器的信号以及用于控制EGR阀的信号。通过获取空气系统中每个控制变量对各个被控变量影响的传递函数,以计算节气门、增压器、EGR阀之间的解耦传递函数,然后将解耦传递函数作用于节气门、增压器以及EGR阀的控制,使得各控制变量能够单独的作用在各自的被控变量之上,避免由于耦合导致的性能限制。(The invention discloses a method for controlling an air system of an engine, wherein control variables in the air system comprise a throttle opening, a supercharger opening and an EGR valve opening, and the controlled variables comprise air flow, supercharging pressure and EGR flow, and the method comprises the following steps: obtaining a transfer function of each control variable influencing each controlled variable; obtaining a decoupling transfer function among a throttle valve, a supercharger and an EGR valve according to the transfer function; a signal for controlling a throttle, a signal for controlling a supercharger, and a signal for controlling an EGR valve are generated based on the decoupled transfer function. The decoupling transfer function among the throttle valve, the supercharger and the EGR valve is calculated by obtaining the transfer function of each control variable in the air system on the influence of each controlled variable, and then the decoupling transfer function is acted on the control of the throttle valve, the supercharger and the EGR valve, so that each control variable can act on each controlled variable independently, and the performance limit caused by coupling is avoided.)

1. An air system control method of an engine, characterized in that control variables in the air system are a throttle opening, a supercharger opening, and an exhaust gas recirculation EGR valve opening, the controlled variables being an air flow rate, a supercharging pressure, and an EGR flow rate, the method comprising:

obtaining a transfer function of each control variable influencing each controlled variable;

obtaining a decoupling transfer function among a throttle valve, a supercharger and an EGR valve according to the transfer function;

generating a control signal for controlling the throttle, a control signal for controlling the supercharger, and a control signal for controlling the EGR valve according to the decoupled transfer function.

2. The method of claim 1, wherein obtaining the transfer function of the effect of each control variable on each controlled variable comprises:

and acquiring parameters of the control variables and parameters of each controlled variable under different working conditions of the engine aiming at each control variable, and acquiring a transfer function of the control variables influencing each controlled variable under different working conditions according to the acquired parameters of the control variables and the parameters of each controlled variable.

3. The method of claim 1, wherein said deriving a decoupled transfer function between a throttle valve, a supercharger, and an EGR valve from said transfer function when said throttle valve is in an open loop control condition comprises:

obtaining a decoupling transfer function from the throttle valve to the supercharger according to the transfer function of the influence of the throttle valve opening degree on the supercharging pressure and the transfer function of the influence of the supercharger opening degree on the supercharging pressure;

and obtaining a decoupling transfer function from the throttle valve to the EGR valve according to the transfer function of the influence of the throttle valve opening degree on the EGR flow and the transfer function of the influence of the EGR valve opening degree on the EGR flow.

4. The method of claim 1, wherein said deriving a decoupled transfer function between a throttle valve, a supercharger, and an EGR valve from said transfer function while said throttle valve is in a closed-loop control condition comprises:

obtaining a decoupling transfer function from the throttle valve to the supercharger according to the transfer function of the influence of the throttle valve opening degree on the supercharging pressure and the transfer function of the influence of the supercharger opening degree on the supercharging pressure;

according to a transfer function of the influence of the opening degree of the throttle valve on the EGR flow and a transfer function of the influence of the opening degree of the EGR valve on the EGR flow, a decoupling transfer function from the throttle valve to the EGR valve is obtained;

obtaining a decoupling transfer function from the supercharger to the throttle according to the transfer function of the influence of the supercharger opening degree on the air flow and the transfer function of the influence of the throttle opening degree on the air flow;

and obtaining a decoupling transfer function from the EGR valve to the throttle valve according to the transfer function of the influence of the opening of the EGR valve on the air flow and the transfer function of the influence of the opening of the throttle valve on the air flow.

5. The method according to any one of claims 1 to 4, wherein the influence of the EGR valve opening degree on the boost pressure and the influence of the supercharger opening degree on the EGR flow rate are ignored.

6. An air system control apparatus of an engine, characterized in that control variables in the air system are a throttle opening, a supercharger opening, and an EGR valve opening, the controlled variables being an air flow amount, a supercharging pressure, and an EGR flow amount, the apparatus comprising:

the transfer function acquisition module is used for acquiring the transfer function of each control variable influencing each controlled variable;

the decoupling calculation module is used for obtaining a decoupling transfer function among the throttle valve, the supercharger and the EGR valve according to the transfer function;

a control module to generate a control signal to control the throttle, a control signal to control the supercharger, and a control signal to control the EGR valve based on the decoupled transfer function.

7. The device according to claim 6, wherein the transfer function obtaining module is specifically configured to collect, for each controlled variable, parameters of the controlled variable and parameters of each controlled variable under different operating conditions of the engine, and obtain, according to the collected parameters of the controlled variable and parameters of each controlled variable, a transfer function that the controlled variable affects each controlled variable under different operating conditions.

8. The device according to claim 6, wherein the decoupling calculation module is configured to obtain a decoupling transfer function from the throttle valve to the supercharger based on a transfer function of an influence of a throttle opening on the boost pressure and a transfer function of an influence of a supercharger opening on the boost pressure when the throttle valve is in an open-loop control condition; and obtaining a decoupling transfer function from the throttle valve to the EGR valve according to the transfer function of the influence of the throttle valve opening degree on the EGR flow and the transfer function of the influence of the EGR valve opening degree on the EGR flow.

9. The device according to claim 6, wherein the decoupling calculation module is configured to obtain a decoupling transfer function from the throttle valve to the supercharger based on a transfer function of an influence of a throttle opening on the boost pressure and a transfer function of an influence of a supercharger opening on the boost pressure when the throttle valve is in a closed-loop control condition; according to a transfer function of the influence of the opening degree of the throttle valve on the EGR flow and a transfer function of the influence of the opening degree of the EGR valve on the EGR flow, a decoupling transfer function from the throttle valve to the EGR valve is obtained; obtaining a decoupling transfer function from the supercharger to the throttle according to the transfer function of the influence of the supercharger opening degree on the air flow and the transfer function of the influence of the throttle opening degree on the air flow; and obtaining a decoupling transfer function from the EGR valve to the throttle valve according to the transfer function of the influence of the opening of the EGR valve on the air flow and the transfer function of the influence of the opening of the throttle valve on the air flow.

10. An air system of an engine, characterized in that control variables in the air system are a throttle opening, a supercharger opening, and an EGR valve opening, the controlled variables being an air flow rate, a supercharging pressure, and an EGR flow rate, the system comprising:

the control device is used for acquiring a transfer function of each control variable influencing each controlled variable, acquiring a decoupling transfer function among a throttle valve, a supercharger and an EGR valve according to the transfer function, and generating a control signal for controlling the throttle valve, a control signal for controlling the supercharger and a control signal for controlling the EGR valve according to the decoupling transfer function;

a throttle valve for opening or closing according to a control signal for controlling the throttle valve;

a supercharger for adjusting a duty ratio according to a control signal for controlling the supercharger;

an EGR valve for opening or closing according to a control signal for controlling the EGR valve.

Technical Field

The invention relates to the technical field of engines, in particular to an air system control method and device of an engine and an air system.

Background

With the continuous development of engine technology, variable parameters needing closed-loop control in an engine air system are more and more, the relevance of each variable parameter in the engine air system is stronger, closed-loop control methods such as PID (Proportional-Integral-Derivative) and the like cannot meet the closed-loop control requirements under all working conditions simply, and when the control of fresh air or boost pressure is unstable, the driving feeling of a whole vehicle is poor, and a driver can feel more obvious shaking. When EGR (Exhaust Gas Recirculation) flow control in an air system is unstable, problems such as misfires and knocking occur, which adversely affect the performance of the engine.

Disclosure of Invention

The present invention is directed to an air system control method and device for an engine and an air system, which are provided to overcome the above-mentioned disadvantages of the prior art, and the object of the present invention is achieved by the following means.

A first aspect of the invention provides an air system control method of an engine in which control variables are a throttle opening, a supercharger opening, and an exhaust gas recirculation EGR valve opening, the controlled variables being an air flow rate, a supercharging pressure, and an EGR flow rate, the method comprising:

obtaining a transfer function of each control variable influencing each controlled variable;

obtaining a decoupling transfer function among a throttle valve, a supercharger and an EGR valve according to the transfer function;

generating a control signal for controlling the throttle, a control signal for controlling the supercharger, and a control signal for controlling the EGR valve according to the decoupled transfer function.

A second aspect of the present invention provides an air system control apparatus of an engine in which control variables are a throttle opening, a supercharger opening, and an exhaust gas recirculation EGR valve opening, the controlled variables having an air flow rate, a supercharging pressure, and an EGR flow rate, the apparatus comprising:

the transfer function acquisition module is used for acquiring the transfer function of each control variable influencing each controlled variable;

the decoupling calculation module is used for obtaining a decoupling transfer function among the throttle valve, the supercharger and the EGR valve according to the transfer function;

a control module to generate a control signal to control the throttle, a control signal to control the supercharger, and a control signal to control the EGR valve based on the decoupled transfer function.

A third aspect of the present invention provides an air system of an engine in which control variables are a throttle opening, a supercharger opening, and an exhaust gas recirculation EGR valve opening, the controlled variables being an air flow rate, a supercharging pressure, and an EGR flow rate, the system comprising:

the control device is used for acquiring a transfer function of each control variable influencing each controlled variable, acquiring a decoupling transfer function among a throttle valve, a supercharger and an EGR valve according to the transfer function, and generating a control signal for controlling the throttle valve, a control signal for controlling the supercharger and a control signal for controlling the EGR valve according to the decoupling transfer function;

a throttle valve for opening or closing according to a control signal for controlling the throttle valve;

a supercharger for adjusting a duty ratio according to a control signal for controlling the supercharger;

an EGR valve for opening or closing according to a control signal for controlling the EGR valve.

Based on the air system control method and device of the engine in the first aspect and the second aspect, the invention has the following beneficial effects:

the decoupling transfer function among the three control variables of the throttle valve, the supercharger and the EGR valve in the air system is obtained through calculation by obtaining the transfer function of the influence of each control variable in the air system on each controlled variable, and then the decoupling transfer function is acted on the control of the three control variables of the throttle valve, the supercharger and the EGR valve, so that each control variable can act on each controlled variable independently, the control loops of each control variable become more independent, and the performance limitation caused by coupling is avoided.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a flowchart illustrating an embodiment of a method of controlling an air system of an engine according to the present disclosure in accordance with an exemplary embodiment;

FIG. 2 is a schematic diagram illustrating the effect of a step change in a control variable on a controlled variable according to the present invention;

FIG. 3 is a schematic structural diagram of a decoupling control system according to the present invention;

FIG. 4 is a schematic structural diagram of another decoupling control system according to the present invention;

fig. 5 is a schematic structural diagram showing an air system control apparatus of an engine according to an exemplary embodiment of the present invention.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, these information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present invention. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.

The control variables in the engine air system are: the opening of a throttle valve, the opening of an EGR valve and the opening of a supercharger, wherein the three control variables respectively correspond to controlled variables: air flow, EGR flow, boost pressure. In addition to the variation of the controlled variable corresponding to any one of the control variables, the remaining controlled variables are also varied by the variation, so that the control loops of the respective control variables in the air system have mutually influencing factors, resulting in the limited performance of the air system.

The invention analyzes the coupling relation existing in the air system and corrects the control loop of the air system in a decoupling mode so as to optimize the control effect of the air system of the engine.

The air system control method proposed by the present invention is explained in detail below with specific embodiments.

Fig. 1 is a flowchart illustrating an embodiment of an air system control method of an engine according to an exemplary embodiment of the present invention, which is applied to a control device, which may be an engine ECU, or a control device dedicated to control of an air system. As shown in fig. 1, the air system control method of the engine includes the steps of:

step 101: and acquiring the transfer function of each control variable influencing each controlled variable.

In the present embodiment, the control variables in the air system are the throttle opening, the supercharger opening, and the EGR valve opening, and the air flow amount, the supercharging pressure, and the EGR flow amount are respectively corresponding controlled variables. The transfer function of the influence of the control variable on the controlled variable refers to a conversion function between the input parameter and the output parameter, which is obtained by taking the control variable as the system input parameter and the controlled variable as the system output parameter.

In some embodiments, parameters of the controlled variable and parameters of each controlled variable under different operating conditions of the engine can be collected for each controlled variable, and a transfer function of the controlled variable on each controlled variable under different operating conditions can be obtained according to the collected parameters of the controlled variable and the parameters of each controlled variable.

For example, taking the influence of the throttle opening control variable on the boost pressure controlled variable as an example, a working condition parameter may be set for the engine, then a throttle opening parameter and a boost pressure parameter which are continuous in time are acquired, then the acquired throttle opening parameter is fitted to obtain an input function x (t), the acquired boost pressure parameter is fitted to obtain an output function y (t), and then the quotient w(s) (y (s)/x (s)) of the lagrange transformation of x (t) and the lagrange transformation of y (t) is used as a transfer function of the influence of the throttle opening on the boost pressure; based on the same principle, a working condition parameter is set for the engine, and a transfer function of the influence of the throttle opening on the boost pressure is obtained.

Since the transfer function is determined by the intrinsic characteristics of the system, the transfer function of the influence of the throttle opening degree on the boost pressure under different working conditions is only different in coefficient, and the other factors are the same.

In one example, the state parameters for engine operating conditions may include engine speed and engine intake charge.

Step 102: and obtaining a decoupling transfer function among the throttle valve, the supercharger and the EGR valve according to the transfer function.

Because any one control variable is adjusted independently, except the corresponding controlled variable changes, other controlled variables also change due to the change, so that the control loops of all the control variables in the air system have factors influencing each other, and an air system model can be established according to the control variables and the controlled variables, wherein the model is as follows:

wherein, MF _ air, PTP and MF _ EGR are three controlled variables of air flow, supercharging pressure and EGR flow respectively; wdkba, ldtvm and agrvp are respectively three control variables of throttle valve opening, supercharger opening and EGR valve opening;as a model matrix, G₁₁Representing a transfer function of the throttle opening on the influence of the air flow, G₁₂Representing the transfer function of the effect of supercharger opening on air flow, G₁₃Representing the transfer function of the EGR valve opening on the air flow, G₂₁A transfer function, G, representing the influence of throttle opening on boost pressure₂₂A transfer function, G, representing the effect of the supercharger opening on the boost pressure₂₃Transfer function, G, representing the effect of EGR valve opening on boost pressure₃₁Transfer function, G, representing the effect of throttle opening on EGR flow₃₂Transfer function, G, representing the effect of supercharger opening on EGR flow₃₃A transfer function representing the effect of EGR valve opening on EGR flow.

By the pair G_(s)The following derivation is made:

the decoupling matrix is defined according to the feedforward compensation as follows:

wherein the content of the first and second substances,is G_p1(s)The inverse matrix of (c).

By matrix inversion property, the following results are obtained:

wherein, | G_p1(s)L is G_p1(s)The determinant (c) of (a),is G_p1(s)The companion matrix of (a).

G is to be_p1(s)And G_p2(s)And substituting and obtaining the following result according to the calculation method of the adjoint matrix:

after arrangement, the following compensation decoupling matrix is obtained:

the influence of the step change of each control variable on each controlled variable is experimentally tested, and is shown in fig. 2, wherein the graph (a), the graph (b) and the graph (c) respectively show the influence of the step change of the throttle opening, the supercharger opening and the EGR valve opening on the air flow, the graph (d), the graph (e) and the graph (f) respectively show the influence of the step change of the throttle opening, the supercharger opening and the EGR valve opening on the boost pressure, and the graph (g), the graph (h) and the graph (i) respectively show the influence of the step change of the throttle opening, the supercharger opening and the EGR valve opening on the EGR flow.

It can be seen from this that the EGR valve opening degree shown in the diagram (f)The influence on the boost pressure and the influence on the EGR flow by the supercharger opening shown in the graph (h) are negligible, i.e. G in the model matrix₂₃And G₃₂Are all 0, so the compensation decoupling matrix can become:

wherein the content of the first and second substances,representing the decoupled transfer function of the supercharger to the throttle,representing the decoupled transfer function of the EGR valve to the throttle,representing the throttle to supercharger decoupled transfer function,representing the decoupled transfer function of the throttle to the EGR valve.

Step 103: a control signal for controlling a throttle, a control signal for controlling a supercharger, and a control signal for controlling an EGR valve are generated based on the decoupled transfer function.

In some embodiments, referring to the decoupled control system shown in FIG. 3, the throttle, supercharger, and EGR valve are all in closed-loop control, and control signal generation for the throttle requires a decoupled transfer function from the supercharger to the throttleDecoupled transfer function of EGR valve to throttleAnd obtaining the throttle opening required by the closed-loop control of the throttle; control signal for superchargerNumber generation, according to the decoupled transfer function of the throttle to the superchargerObtaining the opening degree of the supercharger required by closed-loop control of the supercharger; for the control signal generation of the EGR valve, a decoupling transfer function from the throttle valve to the EGR valve is requiredAnd the EGR valve opening required for EGR valve closed-loop control.

Therefore, when the throttle valve is in a closed-loop control condition, the decoupling transfer functions among the throttle valve, the supercharger and the EGR valve are required to be obtained as follows: decoupled transfer function of throttle to superchargerDecoupled transfer function of throttle to EGR valveDecoupled transfer function of supercharger to throttleDecoupled transfer function of EGR valve to throttle

In other embodiments, referring to the decoupled control system of FIG. 4, the throttle is in an open-loop control condition and the supercharger and EGR valve are in a closed-loop control condition, such that all factors have negligible effect on the throttle, G₁₂And G₁₃Are all 0.

Aiming at the generation of a control signal of the throttle valve, the control signal is obtained only according to the throttle valve opening degree required by the open-loop control of the throttle valve; for the control signal generation of the supercharger, it is necessary to rely on a decoupled transfer function of the throttle to the superchargerObtaining the opening degree of the supercharger required by closed-loop control of the supercharger; for the control signal generation of the EGR valve, a decoupling transfer function from the throttle valve to the EGR valve is requiredAnd the EGR valve opening required for EGR valve closed-loop control.

Therefore, when the throttle valve is in an open-loop control condition, the decoupling transfer functions among the throttle valve, the supercharger and the EGR valve need to be obtained as follows: decoupled transfer function of throttle to superchargerAnd decoupled transfer function of throttle to EGR valve

As shown in fig. 4 again, assume that the transfer function of the influence of the throttle opening on the boost pressure under different operating conditions is as follows:

the transfer function of the influence of the throttle opening on the EGR flow under different working conditions is as follows:

the transfer function of the influence of the opening degree of the supercharger on the supercharging pressure under different working conditions is as follows:

the transfer function of the influence of the opening of the EGR valve on the EGR flow under different working conditions is as follows:

wherein k is₂₁、k₃₁、k₂₂、k₃₃All representing coefficients of the transfer function under different conditions.

From this, the throttle to supercharger decoupled transfer function is as follows:

the decoupled transfer function of the throttle to EGR valve is as follows:

wherein the content of the first and second substances,andthe gain ratios are all gain ratios of decoupling transfer functions, and due to the fact that coefficients of obtained transfer functions are different under different working conditions, gain ratio MAP graphs under different working conditions can be established in advance, namely each working condition corresponds to one gain ratio, and therefore in the process of generating control signals, the MAP graphs can be searched according to the current working condition parameters of the engine to obtain the corresponding gain ratios.

As can be seen from the above description, taking throttle change and boost pressure control as an example, in the prior art, when the throttle is suddenly opened, the boost pressure will suddenly rise, but at this time, the closed-loop control of the supercharger will rise due to the sudden change of the throttle because it is unknown that the boost pressure will rise, so the duty ratio of the final output will be relatively high, and the actual boost pressure will rise excessively. In the embodiment, when the throttle valve is suddenly opened, the control signal of the throttle valve is directly transmitted to the supercharger control through the decoupling transfer function, so that the final output duty ratio of the supercharger is reduced and then increased, the influence of the throttle valve change on the boost pressure control is avoided, and at the moment, the factor of the throttle valve is eliminated, so that the supercharger control can be calibrated faster.

Taking throttle valve change and EGR flow control as examples, in the process of suddenly opening the throttle valve, a control signal of the throttle valve can be directly transmitted to the EGR valve through a decoupling transfer function to control the EGR valve, so that the EGR valve is opened more, the EGR flow can meet the requirement in time, at the moment, if the regulation is too fast, the EGR flow at the moment is easy to fluctuate only by means of PID regulation, and the EGR flow can gradually reach an accurate set value only by a slow control method.

So far, the flow shown in fig. 1 is completed, a decoupling transfer function among three control variables, namely a throttle valve, a supercharger and an EGR valve, in the air system is obtained through calculation by obtaining a transfer function of each control variable in the air system on the influence of each controlled variable, and then the decoupling transfer function is acted on the control of the three control variables, namely the throttle valve, the supercharger and the EGR valve, so that each control variable can act on each controlled variable independently, further the control loops of each control variable become more independent, and performance limitation caused by coupling is avoided.

The present invention also provides an embodiment of an air system control apparatus of an engine, corresponding to the embodiment of the air system control method of an engine described above.

Fig. 5 is a schematic structural diagram of an air system control device of an engine according to an exemplary embodiment of the present invention, based on the embodiment shown in fig. 1, and as shown in fig. 5, the air system control device of the engine includes:

a transfer function obtaining module 510, configured to obtain a transfer function that each control variable affects each controlled variable;

a decoupling calculation module 520, configured to obtain a decoupling transfer function among the throttle valve, the supercharger, and the EGR valve according to the transfer function;

a control module 530 to generate a control signal to control the throttle, a control signal to control the supercharger, and a control signal to control the EGR valve based on the decoupled transfer function.

In an optional implementation manner, the transfer function obtaining module 510 is specifically configured to collect, for each controlled variable, parameters of the controlled variable and parameters of each controlled variable under different working conditions of the engine, and obtain, according to the collected parameters of the controlled variable and the parameters of each controlled variable, a transfer function that the controlled variable affects each controlled variable under different working conditions.

In an optional implementation manner, when the throttle valve is in an open-loop control condition, the decoupling calculation module 520 is specifically configured to obtain a decoupling transfer function from the throttle valve to the supercharger according to a transfer function of an influence of a throttle opening on a boost pressure and a transfer function of an influence of a supercharger opening on the boost pressure; and obtaining a decoupling transfer function from the throttle valve to the EGR valve according to the transfer function of the influence of the throttle valve opening degree on the EGR flow and the transfer function of the influence of the EGR valve opening degree on the EGR flow.

In an optional implementation manner, when the throttle valve is in a closed-loop control condition, the decoupling calculation module 520 is specifically configured to obtain a decoupling transfer function from the throttle valve to the supercharger according to a transfer function of an influence of a throttle opening on a boost pressure and a transfer function of an influence of a supercharger opening on the boost pressure; according to a transfer function of the influence of the opening degree of the throttle valve on the EGR flow and a transfer function of the influence of the opening degree of the EGR valve on the EGR flow, a decoupling transfer function from the throttle valve to the EGR valve is obtained; obtaining a decoupling transfer function from the supercharger to the throttle according to the transfer function of the influence of the supercharger opening degree on the air flow and the transfer function of the influence of the throttle opening degree on the air flow; and obtaining a decoupling transfer function from the EGR valve to the throttle valve according to the transfer function of the influence of the opening of the EGR valve on the air flow and the transfer function of the influence of the opening of the throttle valve on the air flow.

In an alternative implementation, the effect of EGR valve opening on boost pressure and the effect of supercharger opening on EGR flow are ignored.

The implementation process of the functions and actions of each unit in the above device is specifically described in the implementation process of the corresponding step in the above method, and is not described herein again.

For the device embodiments, since they substantially correspond to the method embodiments, reference may be made to the partial description of the method embodiments for relevant points. The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts 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 modules can be selected according to actual needs to achieve the purpose of the scheme of the invention. One of ordinary skill in the art can understand and implement it without inventive effort.

On the basis of the above-described embodiments, the present invention also provides an air system of an engine in which control variables are a throttle opening, a supercharger opening, and an exhaust gas recirculation EGR valve opening, the controlled variables having an air flow rate, a supercharging pressure, and an EGR flow rate, the system including:

the control device is used for acquiring a transfer function of each control variable influencing each controlled variable, acquiring a decoupling transfer function among a throttle valve, a supercharger and an EGR valve according to the transfer function, and generating a control signal for controlling the throttle valve, a control signal for controlling the supercharger and a control signal for controlling the EGR valve according to the decoupling transfer function;

a throttle valve for opening or closing according to a control signal for controlling the throttle valve;

a supercharger for adjusting a duty ratio according to a control signal for controlling the supercharger;

an EGR valve for opening or closing according to a control signal for controlling the EGR valve.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.