CN114580106A - Engine torque model and construction method thereof - Google Patents

Abstract

The invention provides a construction method of an engine torque model and an engine torque model, and relates to the technical field of model construction methods. The construction method of the engine torque model of the present invention builds an initial ignition angle efficiency model according to a preset ignition angle efficiency curve, and inputs the difference between the actual ignition angle and the optimal ignition angle into the initial ignition angle efficiency model, so as to output the ignition angle efficiency. Substitute multiple sets of arrays into the initial ignition angle efficiency model to obtain multiple ignition angle efficiency models corresponding to all the multiple sets of arrays. The process can make the built engine torque model with high accuracy, thereby improving the accuracy of the engine output torque, and making the torque deviation within Within a certain range, the NVH characteristics of the engine are improved.

Description

A construction method of engine torque model and engine torque model

technical field

The present invention relates to the technical field of model building methods, in particular to a method for building an engine torque model and an engine torque model.

Background technique

Ignition angle efficiency is also called ignition loss rate, that is, the relationship between ignition angle output change and torque change when other control parameters remain unchanged; ignition angle efficiency is the core content of engine torque model calibration, and the accuracy of ignition angle efficiency calibration directly determines The accuracy of torque control has a direct impact on the shifting quality and drivability of the entire vehicle, and also has an indirect impact on engine emissions and fuel consumption performance;

The current existing method for confirming the ignition angle efficiency is polynomial fitting:

Through the acquisition of torque data at different ignition angles under different operating conditions such as engine speed and load, and by filtering the collected data, an ignition angle efficiency curve is fitted through multiple sets of data. The ignition angle efficiency confirmation method introduced above has the following shortcomings: 1). The torque model is not accurate enough: 2). The optimal ignition angle (MBT) represents the ignition angle corresponding to the output maximum torque. Normally, the optimal ignition angle should not be smaller than the basic ignition angle. angle, making the optimal ignition angle output unreasonable.

SUMMARY OF THE INVENTION

An object of the first aspect of the present invention is to provide a method for constructing an engine torque model, which solves the problem of insufficient accuracy of the torque model in the prior art.

Another object of the first aspect of the present invention is to solve the problem that the optimal ignition angle output of the existing torque model is unreasonable.

An object of the second aspect of the present invention is to provide a method of constructing an engine torque model.

In particular, the present invention also provides a method for constructing an engine torque model, wherein the engine torque model includes an ignition angle efficiency model for outputting a target ignition angle efficiency curve, and the method for constructing the ignition angle efficiency model includes the following steps:

Build an initial firing angle efficiency model according to a preset firing angle efficiency curve, where the initial firing angle efficiency model is a mathematical function related to a sine function that includes a plurality of unknown coefficients;

Input the difference between the actual ignition angle and the optimal ignition angle into the initial ignition angle efficiency model to output the ignition angle efficiency, and perform multiple input and output cycles to calculate and obtain multiple sets of arrays containing the values of all unknown coefficients , the optimal ignition angle is calculated and obtained according to the rotational speed and load;

Substitute the multiple groups of arrays into the initial ignition angle efficiency model to obtain multiple ignition angle efficiency models corresponding to the multiple groups of arrays.

Optionally, in the step of building an initial ignition angle efficiency model according to a preset ignition angle efficiency curve, the mathematical relationship of the initial ignition angle efficiency model is:

y=asin(bx+c)+dsin(ex+f)

Among them, y is the ignition angle efficiency, x is the difference between the optimal ignition angle and the actual ignition angle, and a, b, c, d, e, and f are all the unknown coefficients.

Optionally, the mathematical relationship of the initial ignition angle efficiency model is:

y=(acos(b)sin(cx+d)-ccos(d)sin(ax+b))/(acos(b)sin(d)-ccos(d)sin(b)).

Optionally, in the step of inputting the difference between the actual ignition angle and the optimal ignition angle into the initial ignition angle efficiency model, the optimal ignition angle is obtained by calculating the optimal ignition angle model, and the optimal ignition angle is obtained by calculating the optimal ignition angle. The construction method of the corner model includes the following steps:

The relational expression of the optimal ignition angle obtained by adding the basic ignition angle to the ignition angle offset value is constructed as an initial optimal ignition angle model, and the basic ignition angle is calculated and obtained according to the rotational speed and the load;

inputting the rotational speed and the load to the initial optimum firing angle model;

Constraining the ignition angle offset value in the initial optimal ignition angle model to a positive value;

When the initial optimal ignition angle model and the initial ignition angle efficiency model are combined, an input-output cycle of the entire engine torque model is performed to obtain a plurality of target optimal ignition angle models corresponding to different rotational speeds and loads.

Optionally, the initial optimal ignition angle model and the initial ignition angle efficiency model are combined, and an input and output cycle is performed, and a plurality of sets of values of the unknown coefficients are also obtained.

Optionally, after obtaining multiple sets of values of the unknown coefficients, the method further includes:

Bringing the value of any set of the unknown coefficients into the initial ignition angle efficiency model to obtain a target ignition angle efficiency model corresponding to the rotational speed and the load corresponding to the unknown coefficients.

Optionally, the target optimal ignition angle model and the target ignition angle efficiency model are combined, and an input and output cycle is performed, and multiple sets of basic ignition angle arrays and ignition angle offsets corresponding to different rotational speeds and loads are also obtained. Array of values and firing angle efficiency curve.

In particular, the present invention also provides an engine torque model obtained by the above-mentioned construction method of the engine torque model.

Optionally, include:

The ignition angle efficiency model is obtained from an initial ignition angle efficiency model containing multiple unknowns through various inputs and outputs, and then the values of the multiple unknowns are obtained and then brought into the initial ignition angle efficiency model;

The optimal ignition angle model is obtained from the initial optimal ignition angle model and the initial ignition angle efficiency model after multiple inputs and outputs.

Optionally, the initial firing angle efficiency model is a mathematical function related to a sine function that includes a plurality of unknown coefficients;

The mathematical function is y=asin(bx+c)+dsin(ex+f), x is the difference between the optimal ignition angle and the actual ignition angle, y is the ignition angle efficiency, a, b, c, d, e , f is the unknown parameter;

Among them, it is known that x=0 is used as input, y=1 is output, and x=0 is used as input, and y′=0 is used as output, and the initial ignition angle efficiency model is obtained by solving, and the initial ignition angle efficiency model is y=(acos(b)sin(cx+d)-ccos(d)sin(ax+b))/(acos(b)sin(d)-ccos(d)sin(b)).

In this application, an initial ignition angle efficiency model is built according to a preset ignition angle efficiency curve, and the difference between the actual ignition angle and the optimal ignition angle is input into the initial ignition angle efficiency model to output the ignition angle efficiency, and multiple groups of arrays are substituted into the initial ignition angle efficiency model. The ignition angle efficiency model is used to obtain multiple ignition angle efficiency models corresponding to the multiple groups of arrays. The process can make the built engine torque model with high accuracy, thereby improving the accuracy of the engine output torque, and making the torque deviation within a certain range. the NVH characteristics of the engine.

Further, in this application, the relational expression of the optimal ignition angle obtained by adding the basic ignition angle to the ignition angle offset value is also constructed as the initial optimal ignition angle model. The optimal ignition angle model can be obtained through the process of constraining the ignition angle offset value in the ignition angle model to a positive value, and the real-time optimal ignition angle can be larger than the basic ignition angle, so that the output of the optimal ignition angle is reasonable and the output ignition efficiency curve is improved. .

The above and other objects, advantages and features of the present invention will be more apparent to those skilled in the art from the following detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings.

Description of drawings

Hereinafter, some specific embodiments of the present invention will be described in detail by way of example and not limitation with reference to the accompanying drawings. The same reference numbers in the figures designate the same or similar parts or parts. It will be understood by those skilled in the art that the drawings are not necessarily to scale. In the attached picture:

1 is a schematic flowchart of a method for constructing an engine torque model according to a specific embodiment of the present invention;

2 is a schematic flowchart of a method for constructing an engine torque model according to another specific embodiment of the present invention;

3 is a schematic flowchart of a method for constructing an engine torque model according to another specific embodiment of the present invention;

4 is a schematic structural block diagram of an engine torque model according to a specific embodiment of the present invention;

5 is a graph of ignition angle efficiency output by an engine torque model according to a specific embodiment of the present invention;

FIG. 6 is a schematic diagram of the deviation of the engine torque model according to a specific embodiment of the present invention.

Detailed ways

FIG. 1 is a schematic flowchart of a method for constructing an engine torque model according to a specific embodiment of the present invention. As a specific embodiment of the present invention, this embodiment provides a method for constructing an engine torque model. The engine torque model may include an ignition angle efficiency model for outputting a target ignition angle efficiency curve, and the construction method of the ignition angle efficiency model may include the following steps:

Step S100, building an initial firing angle efficiency model according to a preset firing angle efficiency curve, where the initial firing angle efficiency model is a mathematical function related to a sine function and including a plurality of unknown coefficients;

Step S200, input the difference between the actual ignition angle and the optimal ignition angle into the initial ignition angle efficiency model to output the ignition angle efficiency, and perform multiple input and output cycles to calculate and obtain multiple sets of values including all unknown coefficients. Array, the optimal ignition angle is calculated according to the speed and load;

Step S300, substituting multiple groups of arrays into the initial ignition angle efficiency model to obtain multiple ignition angle efficiency models corresponding to all the multiple groups of arrays.

Specifically, before building the initial ignition angle efficiency model, the inventors obtained a large number of ignition angle efficiency curves, the shape of which is generally similar to a sine function. Therefore, when constructing the initial ignition angle efficiency model, the initial ignition angle efficiency model is constructed as a sine function model. Specifically, the initial ignition angle efficiency model y=asin(bx+c)+dsin(ex+f), where y is the ignition angle efficiency, x is the difference between the optimal ignition angle and the actual ignition angle, a, b, c, d, e, and f are all unknown coefficients.

In the actual use of the engine, it is known that when x=0, y=1, and when x=0, y'=0. Bringing it into the above relationship and transforming it, the initial ignition angle efficiency model can be obtained as y=(acos(b)sin(cx+d)-ccos(d)sin(ax+b))/(acos(b) )sin(d)-ccos(d)sin(b)).

In step S200, the difference between the actual ignition angle and the optimal ignition angle is input into the model to output the ignition angle efficiency. After many times of input and output, multiple sets of ignition angle efficiency models can be obtained.

Through the model built in the above manner, a high-precision ignition angle efficiency model can be obtained, thereby improving the accuracy of the output torque of the engine, and making the deviation of the torque accuracy within a certain range, improving the torque characteristics of the engine.

2 is a schematic flowchart of a method for constructing an engine torque model according to another specific embodiment of the present invention; as a specific embodiment of the present invention, the present embodiment inputs the actual ignition angle and the maximum ignition angle into the initial ignition angle efficiency model. In the step of calculating the difference of the advantage fire angle, the optimal ignition angle is obtained by calculating the optimal ignition angle model, and the construction method of the optimal ignition angle model includes the following steps:

Step S400, constructing the relational expression of the optimal ignition angle obtained by adding the basic ignition angle to the ignition angle offset value as an initial optimal ignition angle model, and the basic ignition angle is calculated and obtained according to the rotational speed and the load;

Step S500, input the rotational speed and load to the initial optimal ignition angle model;

Step S600, constrain the ignition angle offset value in the initial optimal ignition angle model to be a positive value;

Step S700, when the initial optimal ignition angle model and the initial ignition angle efficiency model are combined, the input and output cycle of the entire engine torque model is performed to obtain multiple target optimal ignition angle models corresponding to different rotational speeds and loads.

In this embodiment, in the initial ignition angle module, the basic ignition angle can be obtained by inputting the rotational speed and load, and the optimal ignition angle is obtained by adding the basic ignition angle and the ignition angle offset value. To be larger than the base firing angle, it is necessary to constrain the firing angle offset to a positive value.

In this embodiment, since the ignition angle offset value is constrained to be a positive value, the real-time optimal ignition angle can be larger than the basic ignition angle, thereby making the output of the optimal ignition angle reasonable and improving the output of the ignition efficiency curve.

FIG. 3 is a schematic flowchart of a method for constructing an engine torque model according to another specific embodiment of the present invention. As a specific embodiment of the present invention, the method for constructing an engine torque model in this embodiment further includes step S800, merging the initial optimal ignition angle model and the initial ignition angle efficiency model, and performing an input and output cycle, and obtaining multiple sets of unknown the value of the coefficient.

Generally speaking, the number of the value of the position coefficient in the initial optimal ignition angle model determines the output and the number of cycles of the output is at least as large as this number before the value of the position coefficient can be obtained. When the number of input and output loops is more, the more subsequent values are obtained, the more accurate.

After obtaining the values of multiple sets of unknown coefficients, it also includes:

Step S900, bringing the value of any group of unknown coefficients into the initial ignition angle efficiency model to obtain a target ignition angle efficiency model corresponding to the rotational speed and load corresponding to the unknown coefficients.

The target optimal ignition angle model and the target ignition angle efficiency model are combined, and the input and output cycle is performed, and multiple sets of basic ignition angle arrays, ignition angle offset value arrays and ignition angle efficiency curves corresponding to different rotational speeds and loads are obtained.

Therefore, if a set of speed and load cannot be outputted, it is necessary to output multiple speeds and loads. After processing the model, the basic ignition angle array, ignition angle offset value array and ignition angle corresponding to multiple sets of speeds and loads can be obtained. efficiency curve.

FIG. 5 is a graph of ignition angle efficiency output by an engine torque model according to a specific embodiment of the present invention. It can be seen from FIG. 5 that the ignition angle efficiency curve finally output by the engine torque model obtained by the method of the present application is consistent with the actual situation.

FIG. 6 is a schematic diagram of the deviation of the engine torque model according to a specific embodiment of the present invention. In this embodiment, the entire process is to optimize the model by means of the MBC toolbox of Matlab. As shown in FIG. 6 , the accuracy of the engine torque model of this embodiment satisfies the deviation of ±5Nm within 200Nm under all operating conditions, and within the range of ±torque multiplied by 2.5% deviation above 200Nm, the above can also be guaranteed within the variable ignition angle range. At the same time, the optimal ignition angle output is reasonable, that is, the optimal ignition angle is greater than or equal to the basic ignition angle.

Specifically, as a specific embodiment of the present invention, the embodiment further provides an engine torque model, and the engine torque model can be obtained by the above construction method of the engine torque model.

The engine torque model of the present embodiment may include an ignition angle efficiency model and an optimal ignition angle model. Among them, the ignition angle efficiency model and the optimal ignition angle model are first combined with the overall torque model of the current vehicle, and the torque can be output after inputting the engine speed and load. After each rotation speed and load detection torque data, input it into the above model, the engine torque model can be obtained according to the above method.

In this embodiment, the ignition angle efficiency model is obtained from an initial ignition angle efficiency model containing multiple unknowns through various inputs and outputs to obtain the values of the multiple unknowns and then brought into the initial ignition angle efficiency model. The optimal ignition angle model is obtained from the initial optimal ignition angle model and the initial ignition angle efficiency model after multiple inputs and outputs. The initial firing angle efficiency model is a mathematical function with a number of unknown coefficients related to a sine function.

The mathematical function is y=asin(bx+c)+dsin(ex+f), x is the difference between the optimal ignition angle and the actual ignition angle, y is the ignition angle efficiency, a, b, c, d, e, f is an unknown parameter;

Among them, it is known that with x=0 as input, y=1 as output, and with x=0 as input, y′=0 as output, the initial ignition angle efficiency model is obtained by solving, and the initial ignition angle efficiency model is y= (acos(b)sin(cx+d)-ccos(d)sin(ax+b))/(acos(b)sin(d)-ccos(d)sin(b)).

In this embodiment, the accuracy of the engine torque model obtained by the above method satisfies the deviation of ±5Nm within 200Nm under all operating conditions, and within the range of ±torque multiplied by 2.5% above 200Nm, and the standard can also be guaranteed within the range of the variable ignition angle. , and at the same time, make the optimal ignition angle output reasonable, that is, the optimal ignition angle is greater than or equal to the basic ignition angle.

By now, those skilled in the art will recognize that, although various exemplary embodiments of the present invention have been illustrated and described in detail herein, the present invention may still be implemented in accordance with the present disclosure without departing from the spirit and scope of the present invention. The content directly determines or derives many other variations or modifications consistent with the principles of the invention. Accordingly, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims (10)

1. A construction method of an engine torque model, wherein the engine torque model comprises an ignition angle efficiency model for outputting a target ignition angle efficiency curve, and the construction method of the ignition angle efficiency model comprises the steps: Build an initial firing angle efficiency model according to a preset firing angle efficiency curve, where the initial firing angle efficiency model is a mathematical function related to a sine function that includes a plurality of unknown coefficients; Input the difference between the actual ignition angle and the optimal ignition angle into the initial ignition angle efficiency model to output the ignition angle efficiency, and perform multiple input and output cycles to calculate and obtain multiple sets of arrays containing the values of all unknown coefficients , the optimal ignition angle is calculated and obtained according to the rotational speed and load; Substitute the multiple groups of arrays into the initial ignition angle efficiency model to obtain multiple ignition angle efficiency models corresponding to the multiple groups of arrays. 2. the construction method of engine torque model according to claim 1, is characterized in that, in the step of building initial firing angle efficiency model according to preset firing angle efficiency curve, the mathematical relation of described initial firing angle efficiency model is: y=asin(bx+c)+dsin(ex+f) Among them, y is the ignition angle efficiency, x is the difference between the optimal ignition angle and the actual ignition angle, and a, b, c, d, e, and f are all the unknown coefficients. 3. the construction method of engine torque model according to claim 2 is characterized in that, the mathematical relational expression of described initial ignition angle efficiency model is: y=(acos(b)sin(cx+d)-ccos(d)sin(ax+b))/(acos(b)sin(d)-ccos(d)sin(b)). 4. The method for constructing an engine torque model according to any one of claims 1-3, wherein in the step of inputting the difference between the actual ignition angle and the optimal ignition angle into the initial ignition angle efficiency model, The optimal ignition angle is obtained by calculating the optimal ignition angle model, and the construction method of the optimal ignition angle model includes the following steps: The relational expression of the optimal ignition angle obtained by adding the basic ignition angle to the ignition angle offset value is constructed as an initial optimal ignition angle model, and the basic ignition angle is calculated and obtained according to the rotational speed and the load; inputting the rotational speed and the load to the initial optimum firing angle model; Constraining the ignition angle offset value in the initial optimal ignition angle model to a positive value; When the initial optimal ignition angle model and the initial ignition angle efficiency model are combined, an input-output cycle of the entire engine torque model is performed to obtain a plurality of target optimal ignition angle models corresponding to different rotational speeds and loads. 5. The method for constructing an engine torque model according to claim 4, wherein, The initial optimal ignition angle model and the initial ignition angle efficiency model are combined, and an input-output cycle is performed, and a plurality of sets of values of the unknown coefficients are also obtained. 6. The method for constructing an engine torque model according to claim 5, wherein, After obtaining a plurality of sets of values of the unknown coefficients, the method further includes: Bringing any set of values of the unknown coefficients into the initial ignition angle efficiency model to obtain a target ignition angle efficiency model corresponding to the rotational speed and the load corresponding to the unknown coefficients. 7. The method for constructing an engine torque model according to claim 6, wherein the target optimal ignition angle model and the target ignition angle efficiency model are combined, and an input and output cycle is performed to obtain multiple groups of different ignition angles. The corresponding basic ignition angle array, ignition angle offset value array and ignition angle efficiency curve corresponding to the speed and load. 8 . An engine torque model, characterized in that it is obtained by the method for constructing an engine torque model according to any one of claims 1 to 7 . 9. The engine torque model of claim 8, wherein include: an ignition angle efficiency model, obtained from an initial ignition angle efficiency model containing a plurality of unknowns through various inputs and outputs to obtain the values of the plurality of unknowns and then bringing them into the initial ignition angle efficiency model; and The optimal ignition angle model is obtained from the initial optimal ignition angle model and the initial ignition angle efficiency model after multiple inputs and outputs. 10. The engine torque model of claim 9, wherein The initial firing angle efficiency model is a mathematical function related to a sine function that includes a plurality of unknown coefficients; The mathematical function is y=asin(bx+c)+dsin(ex+f), x is the difference between the optimal ignition angle and the actual ignition angle, y is the ignition angle efficiency, a, b, c, d, e , f is the unknown parameter; Among them, it is known that x=0 is used as input, y=1 is output, and x=0 is used as input, and y′=0 is used as output, and the initial ignition angle efficiency model is obtained by solving, and the initial ignition angle efficiency model is y=(acos(b)sin(cx+d)-ccos(d)sin(ax+b))/(acos(b)sin(d)-ccos(d)sin(b)).

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