阅读说明：本技术 内燃机的控制装置 (Control device for internal combustion engine ) 是由 浦野繁幸 佐多宏太 于 2019-05-27 设计创作，主要内容包括：本发明提供内燃机的控制装置,通过有效利用作用于与燃烧有关系的控制量的多个操作量,能够防止相对于由随机性的偏差引起的控制量的变化的过度控制,并担保相对于由随机性的要因以外引起的控制量的变化的适应性。在构成1次的变更循环的各燃烧循环中,计算到第n(1≤n≤N)次的燃烧循环为止的控制量的平均值μ<Sub>n</Sub>,计算平均值μ<Sub>n</Sub>相对于基准正态总体的平均值μ<Sub>o</Sub>的误差μ<Sub>n</Sub>-μ<Sub>o</Sub>。另外,基于数据数为n个的情况下的基准正态总体的标准误差σ<Sub>o</Sub>/n<Sup>1/2</Sup>设定正及负的阈值±Z<Sub>α/2</Sub>*σ<Sub>o</Sub>/n<Sup>1/2</Sup>。然后,基于误差μ<Sub>n</Sub>-μ<Sub>o</Sub>的系列与正的阈值Z<Sub>α/2</Sub>*σ<Sub>o</Sub>/n<Sup>1/2</Sup>的系列的比较及误差μ<Sub>n</Sub>-μ<Sub>o</Sub>的系列与负的阈值-Z<Sub>α/2</Sub>*σ<Sub>o</Sub>/n<Sup>1/2</Sup>的系列的比较,从多个操作量中选择应该变更的操作量。(The invention provides a control device for an internal combustion engine, which can prevent excessive control of the change of a controlled variable caused by random deviation by effectively utilizing a plurality of operation quantities acting on the controlled variable related to combustion, and guarantee adaptability of the control quantity to the change of the controlled variable caused by factors other than the random factors, in each combustion cycle forming 1 change cycle, calculating the average value mu n of the controlled variable until the combustion cycle of the nth (1 ≦ N ≦ N) time, calculating the error mu n -mu o of the average value mu n relative to the average value o of a reference normal population, and setting positive and negative thresholds +/-Z α/2 -sigma o /N 1/2 based on the standard error sigma o /N 1/2 of the reference normal population when the number of data is N, and then selecting the operation quantity to be changed from a plurality of operation quantities to be selected from the series of operation quantities for changing the error mu n -mu o and the series of positive thresholds Z8-sigma o /N 1/2 and the series of error mu n -sigma o - o and the series of negative 3573742.)

1. A control device for an internal combustion engine, comprising:

At least 1 processor; and

At least 1 memory including at least 1 program,

The at least 1 memory and the at least 1 program, with the at least 1 processor, cause the control apparatus to perform:

A control amount calculation process of calculating a control amount related to combustion of the internal combustion engine for each combustion cycle based on information from a sensor that detects a state of the internal combustion engine; and

An operation amount changing process for changing at least 1 operation amount of a plurality of operation amounts acting on the control amount for each of 1 change cycle of N combustion cycles, where 2 is equal to or less than N,

In the operation amount change process, the control device selects a reference normal population of the control amount under the current operation condition of the internal combustion engine from a plurality of reference normal populations set for each operation condition of the internal combustion engine,

In each of the combustion cycles from the 1 st combustion cycle to the nth combustion cycle constituting the change cycle, the control device executes:

Average value calculation processing of calculating an N-cycle average value, which is an average value of the control amounts until the nth combustion cycle, where N is 1. ltoreq. n.ltoreq.N;

An error calculation process of calculating an n-cycle error which is an error of the n-cycle average value with respect to an average value of the reference normal population; and

A threshold setting process of setting a positive change determination threshold and a negative change determination threshold with respect to the n cycle error, respectively, based on a standard error of the reference normal population when the number of data is n,

the control device selects the operation amount to be changed from the plurality of operation amounts based on a comparison between the series of N cycle errors from the 1 st combustion cycle to the nth combustion cycle and the series of positive change determination thresholds and a comparison between the series of N cycle errors from the 1 st combustion cycle to the nth combustion cycle and the series of negative change determination thresholds.

2. The control apparatus of an internal combustion engine according to claim 1,

In the control amount calculation process, the control means calculates, as the control amount, a crank angle at which a combustion ratio becomes a predetermined ratio based on information from a combustion pressure sensor,

In the operation amount change process, the control device changes the ignition timing of the internal combustion engine to an advance side when the n-cycle error exceeds the positive change determination threshold in a predetermined number or more of combustion cycles and the n-cycle error does not exceed the negative change determination threshold in any of the combustion cycles.

3. the control apparatus of an internal combustion engine according to claim 1 or 2,

In the control amount calculation process, the control means calculates, as the control amount, a crank angle at which a combustion ratio becomes a predetermined ratio based on information from a combustion pressure sensor,

In the operation amount change process, the control device changes the ignition timing of the internal combustion engine to a retard side when the n-cycle error exceeds the negative change determination threshold in a predetermined number or more of combustion cycles and the n-cycle error does not exceed the positive change determination threshold in any of the combustion cycles.

4. The control device for an internal combustion engine according to any one of claims 1 to 3,

in the control amount calculation process, the control means calculates, as the control amount, a crank angle at which a combustion ratio becomes a predetermined ratio based on information from a combustion pressure sensor,

In the operation amount change process, the control device changes the EGR valve opening degree of the internal combustion engine to the closing side when the n-cycle error exceeds the positive change determination threshold in a predetermined number or more of combustion cycles and the n-cycle error exceeds the negative change determination threshold in a predetermined number or more of combustion cycles.

5. The control device for an internal combustion engine according to any one of claims 1 to 4,

In the operation amount change processing,

In the threshold value setting process, the control device sets a positive abnormality determination threshold value larger than the positive change determination threshold value and a negative abnormality determination threshold value larger than the negative change determination threshold value, respectively, based on a standard error of the reference normal population when the number of data is n,

The control device changes at least 1 of the plurality of operation amounts so that the internal combustion engine is operated in a fail-safe mode when the n-cycle error exceeds the positive abnormality determination threshold value in a predetermined number or more of combustion cycles or when the n-cycle error exceeds the negative abnormality determination threshold value in a predetermined number or more of combustion cycles.

Technical Field

The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine that feeds back a change in a control amount to an operation amount using hypothesis testing and statistical decision.

background

As a control target having a random variation, for example, combustion, which is one of control targets of an internal combustion engine, can be given. When feedback control is applied to a controlled variable related to such a controlled object, it is necessary to perform conservative control in order to prevent excessive control due to a deviation of the controlled object. However, in the conservative control, it is difficult to secure the adaptability to the change of the control amount.

The change in the control amount includes a change due to a deviation in randomness inherent in the system and a change due to factors other than randomness. The change in the control amount to be dealt with by the feedback control is the latter change caused by the change in the state of the control target. Therefore, in order to prevent excessive control and ensure adaptability, it is necessary to determine which of the former and the latter the change in the controlled variable is. However, generally, many data are necessary to statistically determine the cause of the change in the control amount. Although the accuracy of determination improves as the number of data increases, the time required for collecting data increases, and thus the adaptability decreases.

In order to improve the adaptability, it is necessary to make a judgment with as little data as possible. In this regard, non-patent document 1 described below discloses a method of feeding back a change in a control amount to an operation amount using a hypothesis test and a statistical decision. As a specific example, non-patent document 1 discloses an application example of feedback control for controlling a crank angle (hereinafter, LPP) at which a combustion pressure becomes maximum to a reference value.

When the expected value of the LPP is equal to the reference value, a value (hereinafter, referred to as Z) obtained by dividing the deviation of the average value of the LPP from the reference value by the sampling error of the average value follows a standard normal distribution. If LPP data from the 1 st cycle to the n th cycle are obtained, the average value here is an average value of n data from the 1 st cycle to the n th cycle. In addition, the sampling error of the average value is obtained by dividing the standard deviation of LPP by the square root of the number of data.

Whether Z follows a standard normal distribution can be judged by comparison with a threshold calculated from the level of significance. When Z does not enter the reliability interval defined by the negative threshold and the positive threshold, it can be determined that Z does not follow the normal distribution, that is, the expected value of LPP is not equal to the reference value. When Z enters the reliability interval, Z can be determined to follow a normal distribution, that is, the expected value of LPP is equal to the reference value.

The expected value of the LPP being equal to the reference value means that the change in the LPP in the time series is based on the variation in the randomness inherent in the system. In contrast, the expected value of the LPP is not equal to the reference value means that the change in the LPP in the time series is due to a change other than a factor of randomness. Therefore, by calculating Z for each cycle and determining whether the difference Z has entered the reliability section, it is possible to determine whether or not the LPP is changed by the feedback control for each cycle.

According to the specific feedback control disclosed in non-patent document 1, a value obtained by adding a product of a threshold value and a standard error to a reference value of LPP is set as an upper limit value of LPP, and when an average value of LPP exceeds the upper limit value, the ignition timing is advanced. Further, a value obtained by subtracting the product of the threshold value and the standard error from the reference value of the LPP is set as a lower limit value of the LPP, and when the average value of the LPP exceeds the lower limit value, the ignition timing is retarded. According to the determination method disclosed in non-patent document 1, since statistical determination can be performed without requiring much data, by performing feedback control based on this determination, it is possible to prevent excessive control with respect to a change in the controlled variable due to a deviation in randomness, and guarantee adaptability to a change in the controlled variable due to factors other than randomness.

Patent documents 1, 2, and 3 listed below are examples of documents showing technical levels in technical fields related to the present invention.

Disclosure of Invention

Problems to be solved by the invention

A plurality of operation amounts act on control amounts related to combustion of the internal combustion engine, such as CA50 (the combustion ratio is 50% of the crank angle) and LPP. In the case of the LPP exemplified in non-patent document 1, not only the ignition timing but also the opening degree of the EGR valve acts on the LPP. However, non-patent document 1 discloses only correction of the ignition timing as feedback control of the LPP. That is, in non-patent document 1, no consideration is given to handling in the case where there are a plurality of operation amounts acting on the control amount.

The present invention has been made to solve the above-described problems, and an object of the present invention is to prevent excessive control with respect to a change in a controlled variable due to a random deviation and ensure adaptability to a change in a controlled variable due to factors other than randomness by effectively using a plurality of manipulated variables when the manipulated variables act on the controlled variable related to combustion in an internal combustion engine.

means for solving the problems

The invention provides a control device for an internal combustion engine. The control device for an internal combustion engine of the present invention includes at least 1 processor and at least 1 memory including at least 1 program. The at least 1 memory and the at least 1 program, together with the at least 1 processor, cause the control device to execute the control amount calculation process and the operation amount change process. The control amount calculation process is a process of calculating a control amount related to combustion of the internal combustion engine for each combustion cycle based on information from a sensor that detects a state of the internal combustion engine. The operation amount changing process is a process of changing at least 1 operation amount of a plurality of operation amounts acting on a control amount related to combustion of the internal combustion engine for each change cycle, with N (2 ≦ N) combustion cycles as 1 change cycle.

In the operation amount change process, the control device selects a reference normal population of the control amount under the current operation condition of the internal combustion engine from a plurality of reference normal populations set for each operation condition of the internal combustion engine. Further, in each of the combustion cycles from the 1 st combustion cycle to the nth combustion cycle constituting the change cycle, an average value calculation process, an error calculation process, and a threshold value setting process are executed. The average value calculation process is a process of calculating an N-cycle average value, which is an average value of the control amounts until the nth (1. ltoreq. N. ltoreq.N) combustion cycle. The error calculation process is a process of calculating an n-cycle error, which is an error of the n-cycle average value with respect to the average value of the reference normal population. The threshold setting process is a process of setting a positive change determination threshold and a negative change determination threshold for the n cycle error, respectively, based on the standard error of the reference normal population when the number of data is n. The control device selects an operation amount to be changed from the plurality of operation amounts based on a comparison between a series of N cycle errors from the 1 st combustion cycle to the Nth combustion cycle and a series of positive change determination thresholds and a comparison between a series of N cycle errors from the 1 st combustion cycle to the Nth combustion cycle and a series of negative change determination thresholds. The number of operations to be selected may be 1 or more.

As 1 mode of the control amount calculation process, the control device may calculate, as the control amount, a crank angle at which the combustion ratio becomes a predetermined ratio based on information from the combustion pressure sensor. In this case, the control device may execute the operation amount change processing as in the following example.

in an example of the operation amount changing process, the control device may change the ignition timing of the internal combustion engine to the advance side when the n-cycle error exceeds a positive change determination threshold in a predetermined number or more of combustion cycles and when none of the n-cycle errors exceeds a negative change determination threshold in any of the combustion cycles.

In another example of the operation amount changing process, the control device may change the ignition timing of the internal combustion engine to the retard side when the n-cycle error exceeds the negative change determination threshold in a predetermined number or more of the combustion cycles and when none of the n-cycle errors exceeds the positive change determination threshold in any of the combustion cycles.

In another example of the operation amount changing process, the control device may change the EGR valve opening degree of the internal combustion engine to the closing side when the n-cycle error exceeds a positive change determination threshold value in a predetermined number or more of combustion cycles and the n-cycle error exceeds a negative change determination threshold value in the predetermined number or more of combustion cycles.

In the operation amount change process, the controller may set, in the threshold value setting process, a positive abnormality determination threshold value larger than the positive change determination threshold value and a negative abnormality determination threshold value larger than the negative change determination threshold value, respectively, based on a standard error of the reference normal population when the number of data is n. In this case, when the n-cycle error exceeds the positive abnormality determination threshold value for a predetermined number or more of combustion cycles or the n-cycle error exceeds the negative abnormality determination threshold value for a predetermined number or more of combustion cycles, at least 1 of the plurality of operation amounts may be changed so that the internal combustion engine is operated in the fail-safe mode.

Effects of the invention

the control device for an internal combustion engine according to the present invention configured as described above changes at least 1 operation amount of the plurality of operation amounts acting on the control amount for each change cycle, with N combustion cycles as 1 change cycle. Specifically, the control device selects a reference normal population of the control amount under the current operating condition of the internal combustion engine from a plurality of reference normal populations set for each operating condition of the internal combustion engine. Then, in each combustion cycle from the 1 st combustion cycle to the nth combustion cycle constituting the change cycle, an N-cycle average value which is an average value of the control amount until the nth combustion cycle is calculated, an N-cycle error which is an error of the N-cycle average value with respect to an average value of the reference normal population is calculated, and a positive change determination threshold and a negative change determination threshold with respect to the N-cycle error are set based on a standard error of the reference normal population when the number of data is N. Then, the manipulated variable to be changed is selected from the plurality of manipulated variables based on a comparison between a series of N cycle errors from the 1 st combustion cycle to the nth combustion cycle and a series of positive change determination thresholds, and a comparison between a series of N cycle errors from the 1 st combustion cycle to the nth combustion cycle and a series of negative change determination thresholds.

According to the control device for an internal combustion engine of the present invention operating as described above, the operation amount to be changed can be selected in accordance with the variation of the control amount. This prevents excessive control with respect to a change in the controlled variable due to a variation in randomness, and ensures adaptability to a change in the controlled variable due to factors other than randomness.

Drawings

fig. 1 is a block diagram showing a configuration of an engine control system according to embodiment 1 of the present invention.

fig. 2 is a block diagram showing a process executed by the control device according to embodiment 1 of the present invention.

Fig. 3 is a diagram illustrating hypothesis test in embodiment 1 of the present invention.

Fig. 4 is a diagram showing an example of the test result of the hypothesis test in embodiment 1 of the present invention.

Fig. 5 is a diagram showing an example of the test result of the hypothesis test in embodiment 1 of the present invention.

Fig. 6 is a diagram showing an example of the test result of the hypothesis test in embodiment 1 of the present invention.

fig. 7 is a diagram illustrating a change cycle of the change operation amount.

Fig. 8 is a flowchart showing a control flow of engine control according to embodiment 1 of the present invention.

Fig. 9 is a diagram for explaining hypothesis testing in embodiment 2 of the present invention.

Fig. 10 is a diagram showing an example of the test result of the hypothesis test in embodiment 2 of the present invention.

Fig. 11 is a diagram showing an example of the test result of the hypothesis test in embodiment 2 of the present invention.

Fig. 12 is a diagram showing an example of the test result of the hypothesis test in embodiment 2 of the present invention.

Fig. 13 is a diagram showing an example of the test result of the hypothesis test in embodiment 2 of the present invention.

Fig. 14 is a block diagram showing the configuration of an engine control system according to embodiment 2 of the present invention.

Fig. 15 is a flowchart showing a control flow of engine control according to embodiment 2 of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, in the embodiments described below, when the number, the amount, the range, and the like of each element are mentioned, the present invention is not limited to the mentioned number except for the case where the number is specifically indicated or the case where the number is obviously determined in principle. In addition, the structures, steps, and the like described in the embodiments shown below are not necessarily essential to the present invention, except for the case where they are specifically shown or clearly determined to be the same in principle.