JP2006022706A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device capable of accurately controlling engine speed at the time of idling to a target value. <P>SOLUTION: This control device for an internal combustion engine is provided with a means 41 for calculating target intake amount to control the engine speed to a target value; a means 42 for calculating target ignition timing to control the engine speed to the target value; a means for detecting current intake amount; a means for detecting current ignition timing; a control parameter determination means for determining which of the target intake amount and target ignition timing should be adopted as a control parameter to control the engine speed to the target value; and a means for controlling the engine speed to the target value using the determined control parameter and calculating correction amount of the control parameter. The control parameter determination means determines that it adopts the target intake amount or target ignition timing which causes smaller torque fluctuation as the control parameter to control the engine speed to the target value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a control device that controls an engine speed to a target speed during idling.

  Patent Document 1 discloses a control device for controlling the engine speed to a target speed during idling of an internal combustion engine. This document describes adaptive control using a model that attempts to control the engine speed during idling to the target speed by controlling the intake air amount (hereinafter referred to as “intake air amount adaptive control”), and engine speed during idling. There is disclosed a control device capable of executing adaptive control (hereinafter referred to as “ignition timing adaptive control”) using a model that attempts to control the number to the target rotational speed by controlling the ignition timing (paragraphs 0035 to 0035). 0039). Then, in the control device described in the same document, when the ignition timing is in a region where the torque change is small (region A in FIG. 14) using the map (relationship) shown in FIG. On the other hand, when the ignition timing is in a region where the torque change is large (region B in FIG. 14), ignition timing adaptive control is performed.

JP-A-6-101609

  By the way, in the internal combustion engine, if the intake air amount changes, the relationship between the ignition timing and the torque also changes. That is, the intake air amount is one of the parameters affecting the torque. However, the map in FIG. 14 of Patent Document 1 considers only the ignition timing without considering the intake air amount. That is, in this document, the intake air amount, which is one of the parameters affecting the torque, is ignored, and the intake air amount adaptive control is performed depending on whether the torque fluctuation is large or small based on the map related to the ignition timing. It is determined whether to perform adaptive control. In this case, there is a high possibility that the engine speed during idling is not accurately controlled to the target speed. This is not limited to the engine speed at the time of idling. In general, when the specific output of the internal combustion engine is controlled to the target value, the technical idea described in Patent Document 1 is applied. .

  Accordingly, an object of the present invention is to provide a control device that can accurately control the engine speed during idling to the target speed, and more generally, a control device that can accurately control a specific output of the internal combustion engine to the target value. There is to do.

  In order to solve the above problems, in a first aspect of the invention, in an internal combustion engine controller that controls the engine speed at idling to a target speed by controlling the intake air amount or ignition timing, the engine speed at idling is controlled. Means for calculating the intake air amount with the target engine speed as the target air intake quantity, means for calculating the ignition timing with the engine speed as the target engine speed during idling, and means for detecting the current intake air amount And means for detecting the current ignition timing, and the target engine speed based on the calculated target intake air amount and target ignition timing and the detected current intake air amount and ignition timing. Control parameter determining means for determining which of the calculated target intake air amount and the target ignition timing should be adopted as the control parameter; And a means for controlling the engine speed to the target speed using the control parameter thus calculated and calculating a correction amount of the control parameter, and the torque when the control parameter determination means adopts the target intake air amount. The fluctuation is compared with the torque fluctuation when the target ignition timing is adopted, and it is determined that the control parameter with the smaller torque fluctuation is adopted as the control parameter for setting the engine speed to the target speed.

  In order to solve the above-mentioned problem, in the second invention, a specific output of the internal combustion engine is set to a target value by controlling any one of the first control parameter and the second control parameter which are different from each other. In the control device for an internal combustion engine that performs control, the first control parameter having the specific output as the target value is calculated as the target value of the first control parameter, and the second control using the specific output as the target value Means for calculating the parameter as a target value of the second control parameter; means for detecting the current value of the first control parameter; means for detecting the current value of the second control parameter; Based on the first control parameter and the second control parameter, and the detected value of the current first control parameter and the value of the current second control parameter. Control parameter determining means for determining which of the calculated target value of the first control parameter and the target value of the second control parameter should be adopted as a control parameter for setting the output of Means for controlling a specific output to a target value using the determined target value of the control parameter and calculating a correction amount of the determined control parameter, wherein the control parameter determining means includes a first output The variation of the output of the internal combustion engine that is different from the specific output in the case where the control parameter is employed and the case where the second control parameter is employed is compared, and the control parameter having the smaller variation in the output is compared with the specific parameter. It is decided to adopt it as a control parameter for setting the output to the target value.

According to the first invention, the engine speed during idling is accurately controlled to the target speed.
According to the second aspect of the invention, the specific output of the internal combustion engine is accurately controlled to the target value.

  Embodiments of the present invention will be described below with reference to the drawings. In general, a configuration shown in FIG. 1 is known as a configuration for controlling a certain system using a model (hereinafter referred to as “system control configuration”). In FIG. 1, 1 is a system to be controlled, 2 is a controller, 3 is a model of the system to be controlled (hereinafter referred to as “system model”), and is an inverse model of 4 system model 3 (Hereinafter referred to as “system inverse model”).

  According to the system control configuration shown in FIG. 1, first, an output value (hereinafter referred to as “target output”) Yt to be output from the system 1 is input to the system inverse model 4. An input value (hereinafter referred to as “target input”) Ut to be input to the system 1 for outputting the target output is output.

  The target input Ut is corrected by the correction value ΔU output from the controller 2 and then input to the system 1 and also input to the system model 3. An output value actually output from the system 1 (this is a value obtained by detecting an actual output from the system 1 to be controlled) and an output value output from the system model 3 (this is a system model) 3 is input to the controller 2, and based on this difference (error), the controller 2 corrects the correction value ΔU for correcting the target input Ut described above. Is output.

  According to this system control configuration, if the system inverse model 4 is accurate, the output from the system 1 is accurately controlled to the target output. Therefore, when this system control configuration is applied to control of the internal combustion engine (for example, control for controlling the engine speed at idling to the target speed), it is necessary to accurately obtain a system inverse model of the internal combustion engine. However, because the system model of the internal combustion engine is complicated, it is difficult to accurately obtain the system inverse model of the internal combustion engine. Even if the system inverse model of the internal combustion engine is obtained, it is not accurate. It may not be. For this reason, even if the system control configuration described above is applied to the control of the internal combustion engine, it cannot be expected that the output of the internal combustion engine is accurately controlled to the target value.

  Therefore, in the present embodiment, the configuration shown in FIG. 2 is adopted as the system inverse model. That is, in FIG. 2, as in FIG. 1, 1 is a system to be controlled, 2 is a controller, 3 is a system model, and 4 is a system inverse model. 2, the system model 3, and the system inverse model 4 are the same as those in the system control configuration shown in FIG. 1.

  However, in the present embodiment, the system inverse model 4 includes a system inverse model controller 5 and a system model 6 (this is the same as the system model 3). Specifically, according to the present embodiment, the target output Yt input to the system inverse model 4 is first subtracted by the output value from the system model 6 and then input to the system inverse model controller 5. . And the target input Ut output from the controller 5 is input into the system 1 and the system model 3 similarly to the system control structure shown in FIG. The subsequent processing is the same as that of the system control configuration shown in FIG.

  Further, the target input Ut output from the system inverse model controller 5 is also input to the system model 6, and the value to be subtracted from the target output Yt input to the system inverse model. It is used as

  In the system control configuration of the present embodiment, the system inverse model is constructed using the system model itself, instead of deforming the system model to obtain the system inverse model as in the prior art. Has the advantage that it is very simple.

  Further, as the last of the description of the system control configuration shown in FIG. 2, it will be described that the system inverse model of the system control configuration is a so-called conventional system inverse model.

  Assuming that the transfer function of the system model 6 is P (s) and the transfer function of the system inverse model controller 5 is C (s), the system inverse model 4 shown in FIG. 2 is expressed by the equation (1) in FIG. be able to. Here, when the denominator and the numerator are divided by C, Equation (1) in FIG. 3 becomes Equation (2) in FIG. Further, if C is increased as much as possible, the 1 / C term becomes substantially zero, and therefore equation (2) in FIG. 3 becomes equation (3) in FIG. According to the equation (3) in FIG. 3, the system inverse model 4 of the system control configuration shown in FIG. 2 shows exactly the inverse function (ie, 1 / P) of the transfer function of the system model 3. I understand. (For this concept, see also the explanation regarding FIG. 25 of Japanese Patent Application No. 2003-191439.)

  Next, as an example of a control device using the system control configuration shown in FIG. 2, a control device that controls the engine speed at idling to a target speed will be described. The configuration of the control device of this embodiment is shown in FIGS.

  First, in FIG. 4, reference numeral 41 denotes an intake air amount (that is, a target intake air amount) GAt for calculating (outputting) the engine rotational speed NEt based on the target rotational speed NEt during idling. This is a system inverse model of the internal combustion engine (in the sense that this model is a system inverse model of the internal combustion engine for outputting a target intake air amount, hereinafter this is referred to as an “intake air engine inverse model”). On the other hand, reference numeral 42 denotes an internal combustion engine system for calculating (outputting) an ignition timing (that is, a target ignition timing) STt having the engine speed NEt as the target engine speed NEt based on the target engine speed NEt at the time of idling. This is an inverse model (in the sense that this model is a system inverse model of an internal combustion engine for outputting a target ignition timing, hereinafter this is referred to as an “ignition timing engine inverse model”).

  In the intake air engine inverse model 41, a system model of the internal combustion engine denoted by reference numeral 61 (this is a model of the relationship between the intake air amount and the engine speed, which is hereinafter referred to as "intake air engine model"). ) Corresponds to the system model 6 of FIG. Further, the controller 51 of the intake air engine inverse model 41 corresponds to the controller 5 of the system inverse model 4 of FIG. On the other hand, in the ignition timing engine inverse model 42, a system model of an internal combustion engine denoted by reference numeral 62 (this is a model of the relationship between the ignition timing and the engine speed, hereinafter referred to as the "ignition timing engine model"). ") Corresponds to the system model 6 of FIG. Further, the controller 52 of the ignition timing engine inverse model 41 corresponds to the controller 5 of the system inverse model 4 of FIG.

  In the system control configuration shown in FIG. 4, the target rotational speed NEt is input to each engine inverse model 41, 42. The intake air engine inverse model 41 outputs an intake air amount (target intake air amount) GAt having the engine speed as the target engine speed during idling based on the same principle as the system inverse model 4 in FIG. On the other hand, the ignition timing engine inverse model 42 also outputs an ignition timing (target ignition timing) STt with the engine speed as the target speed during idling, based on the same principle as the system inverse model 4 in FIG.

  The target intake air amount GAt and the target ignition timing STt thus output are input to the system control configuration shown in FIG. That is, in FIG. 5, 33a to 33c are system models of the internal combustion engine (this is a model of the relationship between the ignition timing and the intake air amount and the torque, which is hereinafter referred to as "intake air amount / ignition timing engine model". It is also called).

  The target ignition timing STt is input to the intake air amount / ignition timing engine model 33a. The actual actual intake air amount GA is also input to the engine model 33a. As a result, the engine model 33a outputs the torque Te1 output from the internal combustion engine when the current ignition timing is changed to the target ignition timing STt while maintaining the current intake air amount.

  The target intake air amount GAt is input to the intake air amount / ignition timing engine model 33c. The current actual ignition timing ST is also input to the engine model 33c. As a result, the engine model 33c outputs the torque Te2 output from the internal combustion engine when the current intake amount is changed to the target intake amount GAt while maintaining the current ignition timing.

  Further, the current actual intake air amount GA and the current actual ignition timing STt are input to the intake air amount / ignition timing engine model 33b. As a result, torque Te output from the internal combustion engine is output from the engine model 33b while maintaining the current intake air amount and ignition timing.

  Next, the output Te1 from the intake air amount / ignition timing engine model 33a is subtracted by the output Te from the intake air amount / ignition timing engine model 33b as indicated by reference numeral 71. An absolute value | u | of ΔTe1 obtained by this subtraction (this corresponds to a torque fluctuation amount when the current ignition timing is changed to the target ignition timing) is indicated by reference numeral 81. The absolute value | u | is input to the comparator 90.

  On the other hand, the output Te2 from the intake air amount / ignition timing engine model 33c is subtracted by the output Te from the intake air amount / ignition timing engine model 33b as indicated by reference numeral 71. An absolute value | u | of ΔTe2 obtained by this subtraction (this corresponds to a torque fluctuation amount when the current intake air amount is changed to the target intake air amount) is indicated by reference numeral 82. The absolute value | u | is input to the comparator 90.

  Finally, the comparator 90 determines which of the absolute value of the torque fluctuation amount ΔTe1 and the absolute value of the torque fluctuation amount ΔTe2 is smaller. If the absolute value of the torque fluctuation amount ΔTe1 is smaller, the engine speed A control parameter to be changed in order to control the engine speed to the target rotational speed is an ignition timing. That is, in this case, the engine speed is controlled to the target speed by setting the ignition timing as the target ignition timing while maintaining the intake air amount at the current intake air amount. Specifically, the engine speed is controlled to the target speed by the system control configuration shown in FIG.

  6A, the controller 21 corresponds to the controller 2 in FIG. 2, the internal combustion engine 11 corresponds to the system 1 in FIG. 2, and the engine model 31 corresponds to the system model 3 in FIG. The principle that the engine speed NE of the internal combustion engine 11 is controlled to the target speed is the same as the system control configuration shown in FIG. The engine model 31 is the same as the intake air engine model 61.

  On the other hand, when the absolute value of the torque fluctuation amount ΔTe2 is smaller, the control parameter that should be changed to control the engine speed to the target speed is the intake air amount. That is, in this case, the engine speed is controlled to the target speed by setting the intake air amount as the target intake air amount while maintaining the ignition timing at the current ignition timing. Specifically, the engine speed is controlled to the target engine speed by the system control configuration shown in FIG.

  6B, the controller 22 corresponds to the controller 2 in FIG. 2, the internal combustion engine 11 corresponds to the system 1 in FIG. 2, and the engine model 32 corresponds to the system model 3 in FIG. The principle that the engine speed NE of the internal combustion engine 11 is controlled to the target speed is the same as the system control configuration shown in FIG. The engine model 32 is the same as the ignition timing engine model 62.

  Thus, according to the present embodiment, at the time of idling, the engine speed can be controlled to the target speed while suppressing torque fluctuation as small as possible.

  The concept of the system control configuration of the present embodiment is generally the case where any one of a plurality of specific control parameters is controlled in order to set a specific output of the internal combustion engine as a target value. Is also applicable. In this case, it is determined which one of the certain specific control parameters is controlled so that the fluctuation of the output of the internal combustion engine different from the specific output is reduced.

It is a figure which shows the general system control structure using a model. It is a figure which shows the system control structure of this embodiment. It is the figure which showed the type | formula for demonstrating the system inverse model of the system control structure shown in FIG. It is a figure which shows a part of control apparatus of this embodiment. It is a figure which shows a part of control apparatus of this embodiment. It is a figure which shows a part of control apparatus of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 System 2,5,21,22,51,52 Controller 3,6 System model 4 System reverse model 11 Internal combustion engine 31,61 Intake amount engine model 32,61 Ignition timing engine model 33a-33c Intake amount / ignition timing engine model 41 Intake engine reverse model 42 Ignition timing engine reverse model 90 Comparator

Claims (2)

  In an internal combustion engine control system that controls the engine speed at idling to the target speed by controlling the intake air quantity or ignition timing, the intake air quantity with the engine speed as the target speed at idling is calculated as the target air intake quantity. Means for calculating the ignition timing with the engine speed as the target engine speed at idling, the means for detecting the current intake air amount, the means for detecting the current ignition timing, and the above calculation The target intake air amount and the target ignition timing calculated as control parameters for setting the engine speed to the target speed based on the detected target intake air amount and target ignition timing and the detected current intake air amount and ignition timing. Control parameter determining means for determining which of these should be adopted, and the engine speed using the determined control parameter. Means for controlling the rotational speed and calculating the correction amount of the control parameter, and the control parameter determining means adopts a torque fluctuation when the target intake air amount is adopted and a torque when the target ignition timing is adopted. A control apparatus for an internal combustion engine, wherein the control parameter is determined to be adopted as a control parameter for setting the engine speed to a target speed, by comparing the fluctuation with the torque.   In a control apparatus for an internal combustion engine that controls a specific output of an internal combustion engine to a target value by controlling any one of a first control parameter and a second control parameter that are different from each other, the specific output is Means for calculating the first control parameter as the target value as the target value of the first control parameter, and means for calculating the second control parameter with the specific output as the target value as the target value of the second control parameter Means for detecting the current value of the first control parameter, means for detecting the current value of the second control parameter, the calculated first control parameter and second control parameter, and the detection A control parameter for setting a specific output as a target value based on the current first control parameter value and the current second control parameter value, Control parameter determining means for determining which of the calculated target value of the first control parameter and the target value of the second control parameter should be adopted, and using the determined target value of the control parameter Means for controlling a specific output to a target value and calculating a correction amount of the determined control parameter, wherein the control parameter determination means adopts the first control parameter and the second control. Compare the output fluctuation of the internal combustion engine different from the specific output when the parameter is adopted, and use the control parameter with the smaller output fluctuation as the control parameter for setting the specific output to the target value. A control device for an internal combustion engine, wherein the control device is determined to be adopted.

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