JP2009293601A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control deice for an internal combustion engine guaranteeing the maximum torque of the internal combustion engine regardless of the manufacturing dispersion and aging effect of the internal combustion engine. <P>SOLUTION: When demand torque to the internal combustion engine is maximum torque or more, the valve opening of a throttle valve is set to maximum opening. This maximum opening is the valve opening of the throttle valve when the engine intake quantity becomes maximum, and its learning value is stored in the control device. The maximum opening is learned based on information related to a change in an engine intake quantity acquired at the time of operating the throttle valve when the valve opening of the throttle valve is set to the maximum opening. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  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 provided with an intake air amount adjustment valve for adjusting an engine intake air amount.

  The torque output from the internal combustion engine can be controlled by the amount of air taken into the cylinder (hereinafter referred to as intake air amount). In order to adjust the intake air amount, an intake air amount adjusting valve is provided in the intake pipe of the internal combustion engine. A typical intake air amount adjusting valve is a throttle valve, and an intake valve provided with a continuously variable lift amount mechanism also corresponds to an intake air amount adjusting valve.

  Various techniques have been proposed for controlling the intake air amount adjusting valve. For example, Japanese Patent Laid-Open No. 2001-248487 discloses a technique related to so-called torque demand control for controlling a throttle valve based on a required torque (hereinafter referred to as a conventional technique). In torque demand control, a target air amount is calculated from the required torque and the engine speed, and the valve opening of the throttle valve is determined based on the target air amount and the engine speed.

In the above-described prior art, in order to maximize the output performance of the internal combustion engine regardless of manufacturing variations, changes over time, and environmental changes of the internal combustion engine, the required torque is reduced to the current engine speed in the region where the accelerator opening is greater than the predetermined opening. A value larger than the designed maximum torque at the speed is set. More specifically, the value of the required torque in the region above the predetermined opening is set with reference to a map that defines the relationship between the engine speed and the required torque. In the map, the required torque is defined so as to be the upper limit value of the manufacturing variation range of the maximum torque at each engine speed or a value slightly larger than that.
JP 2001-248487 A

  However, as described in the above publication, the output performance of the internal combustion engine changes with time. This also applies to the throttle valve opening-torque characteristics, that is, the relationship between the throttle valve opening and torque. In the torque demand control as in the above prior art, since the valve opening of the throttle valve is set based on the required torque, the required torque cannot be accurately realized when the valve opening-torque characteristic changes. . Therefore, even if the required torque is set to a value larger than the designed maximum torque as in the prior art, the maximum torque may not necessarily be output depending on the degree of change with time of the internal combustion engine.

  The present invention has been made to solve the above-described problems, and provides a control device for an internal combustion engine that can guarantee the maximum torque of the internal combustion engine regardless of manufacturing variations and changes over time of the internal combustion engine. With the goal.

In order to achieve the above object, a first invention provides a control apparatus for an internal combustion engine including an intake air amount adjusting valve for adjusting an engine intake air amount.
Maximum opening degree storage means for storing the valve opening degree of the intake amount adjustment valve when the engine intake amount becomes maximum as the maximum opening degree of the intake amount adjustment valve;
Request torque acquisition means for acquiring a request torque to the internal combustion engine;
Valve opening setting means for setting the valve opening of the intake air amount adjustment valve to the maximum opening when the required torque is equal to or greater than the maximum torque that can be output by the internal combustion engine;
Valve control means for operating the intake air amount adjustment valve so as to change the valve opening from the maximum opening when the valve opening of the intake air amount adjusting valve is set to the maximum opening;
An intake air amount change information acquisition means for acquiring information related to a change in the engine intake air amount when the valve opening of the intake air amount adjustment valve changes from the maximum opening (hereinafter referred to as intake air amount change information);
Maximum opening learning means for learning the maximum opening based on the intake air amount change information;
It is characterized by having.

According to a second invention, in the first invention,
The valve control means changes the valve opening degree of the intake air amount adjustment valve from the maximum opening degree when the internal combustion engine is in a steady state.

According to a third invention, in the first or second invention,
The valve control means is characterized in that the valve opening of the intake air amount adjusting valve is gradually increased with respect to the maximum opening.

A fourth invention is any one of the first to third inventions,
The intake air amount change information acquisition means acquires the intake air amount change information using a sensor disposed in the intake system of the internal combustion engine and a sensor disposed in the exhaust system of the internal combustion engine. .

According to a fifth invention, in any one of the first to third inventions,
The internal combustion engine is an internal combustion engine having an air-fuel ratio sensor in an exhaust system,
The intake air amount change information acquisition means acquires the air-fuel ratio sensor signal as the intake air amount change information.

A sixth invention is any one of the first to third inventions,
The internal combustion engine is an internal combustion engine having an air-fuel ratio sensor in an exhaust system,
Feedback control means for performing feedback control of the fuel supply amount so that the air-fuel ratio of the exhaust gas becomes a predetermined air-fuel ratio based on the signal of the air-fuel ratio sensor,
The intake air amount change information acquisition unit acquires a feedback correction amount related to the feedback control as the intake air amount change information.

  Whether the valve opening degree of the intake air amount adjustment valve is the valve opening degree that maximizes the engine intake air amount can be verified by the change state of the engine intake air amount when the intake air amount adjustment valve is operated. For example, if the intake air amount adjustment valve is operated from a certain valve opening to the open side, if the valve opening at that time is a valve opening that maximizes the engine intake air amount, the change in the engine intake air amount will be Does not occur. However, when the valve opening at that time is smaller than the valve opening that maximizes the engine intake amount, the engine intake amount increases when the intake amount adjustment valve is operated to the open side. On the other hand, when the valve opening at that time is larger than the valve opening that maximizes the engine intake air amount, when the intake air amount adjustment valve is operated to the closed side, the valve opening that maximizes the engine intake air amount is opened. The engine intake amount does not change until it becomes smaller than the degree.

  According to the first aspect of the invention, the valve opening that maximizes the engine intake air amount is stored as the maximum opening, and the maximum opening is learned on the basis of information relating to changes in the engine intake air amount. Therefore, according to the first aspect of the invention, it is possible to accurately realize the valve opening degree that maximizes the engine intake air amount regardless of manufacturing variations and changes over time of the internal combustion engine, and as a result, the output of the maximum torque is ensured. be able to.

  According to the second invention, by learning the maximum opening when the internal combustion engine is in a steady state, it is possible to eliminate the influence of the transient fluctuation of the engine intake air amount on the learned value of the maximum opening. . Therefore, according to the second aspect of the invention, it is possible to more accurately realize the valve opening degree that maximizes the engine intake air amount.

  According to the third aspect of the invention, by learning while gradually increasing the valve opening, the influence of the transient fluctuation of the engine intake amount accompanying the change in the valve opening on the learning value of the maximum opening is eliminated. can do.

  According to the fourth aspect of the invention, by using the sensor provided in the intake system and the sensor provided in the exhaust system in combination, the robustness at the time of failure of the sensor can be improved.

  According to the fifth aspect of the invention, the intake air amount change information can be acquired using the air-fuel ratio sensor provided in the exhaust system.

  According to the sixth aspect, the feedback correction amount related to the feedback control for setting the air-fuel ratio to the predetermined air-fuel ratio can be used for learning the maximum opening.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 4.

  The control device of the present embodiment is configured as a torque demand type control device that acquires the required torque and controls the operation of the intake air amount adjusting valve so as to realize the required torque. FIG. 1 is a block diagram showing the configuration of the control device of the present embodiment. The internal combustion engine according to the present embodiment includes a throttle valve 2 as an intake air amount adjustment valve. As an element for controlling the operation of the throttle valve 2, the control device of the present embodiment includes a required torque acquisition unit 20, a throttle valve opening setting unit 22, and a throttle valve control unit 24. The functions of these elements will be described below.

  The required torque for the internal combustion engine is acquired by the required torque acquisition unit 20. The requested torque acquisition unit 20 receives an accelerator opening signal from the accelerator opening sensor 10. The accelerator opening signal is a signal reflecting the driver's accelerator operation, and the driver's torque request is included in the accelerator opening signal. The requested torque acquisition unit 20 converts the input accelerator opening signal into a torque value and acquires it as a driver requested torque.

  The requested torque acquisition unit 20 also receives a signal from another control system such as a vehicle stability control system (VSC) or a traction control system (TRC). When the torque request is included in the signals from these control systems, the required torque acquisition unit 20 calculates a torque necessary for each control and acquires it as other control request torque. Then, a value obtained by adding the other control request torque to the aforementioned driver request torque is calculated as the final request torque.

  The throttle valve opening setting unit 22 converts the required torque acquired by the required torque acquisition unit 20 into the required opening of the throttle valve 2. The throttle valve control unit 24 generates a control signal for operating the throttle valve 2 based on the required opening set by the throttle valve opening setting unit 22. Through such a series of processes, the operation of the throttle valve 2 is controlled to achieve the required torque.

  According to the configuration shown in FIG. 1, the operating characteristic of the throttle valve 2 with respect to the required torque is determined by the processing in the throttle valve opening setting unit 22. Next, the internal configuration of the throttle valve opening setting unit 22 will be described. FIG. 2 is a block diagram showing the configuration of the throttle valve opening setting unit 22.

  The throttle valve opening setting unit 22 includes a plurality of calculation elements for converting the required torque into the valve opening (requested opening) of the throttle valve 2. If it demonstrates from the upstream of the signal in FIG. 2, the TQ-KL conversion part 50 which converts the request torque TQ into the request | requirement filling efficiency KL is arrange | positioned in the most upstream. The required torque is input to the TQ-KL converter 50. The TQ-KL conversion unit 50 converts the required torque TQ into the required intake air amount KL using a map or a polynomial approximation formula. In the map or the polynomial approximation, the valve timing of the intake valve and the exhaust valve, the operating state of ACIS (Acoustic Control Induction System), the air-fuel ratio, and the like are used as parameters.

  Next to the TQ-KL conversion unit 50, a KL-PM conversion unit 52 is arranged. The required intake air amount KL obtained by the TQ-KL converter 50 is converted into the required intake pipe pressure PM by the KL-PM converter 52. The KL-PM conversion unit 52 converts the required intake air amount KL into the required intake pipe pressure PM by a map or a polynomial approximate expression. In the map or polynomial approximate expression, the valve timing of the intake valve and the exhaust valve, the ACIS operating state, the air-fuel ratio, etc. are used as parameters.

  Next to the KL-PM conversion unit 52, a PMWOT guard unit 54 is arranged. The PMWOT guard unit 54 limits the value of the required intake pipe pressure PM obtained by the KL-PM conversion unit 52 by PMWOT which is an upper limit guard value. When the intake pipe pressure reaches the saturation point, the engine intake amount does not change even if the throttle valve opening is changed. The processing by the PMWOT guard unit 54 is provided to limit useless operation of the throttle valve 2 in such a saturation region. When the required intake pipe pressure PM obtained by the KL-PM conversion unit 52 is larger than PMWOT, the value of the required intake pipe pressure PM output from the PMWOT guard unit 54 is limited to PMWOT.

  A ΔPM calculation unit 58 is disposed downstream of the PMWOT guard unit 54 with the filter 56 interposed therebetween. The required intake pipe pressure PM subjected to the guard process by the PMWOT guard unit 54 is input to the ΔPM calculation unit 58 after the noise component is removed by the filter 56. The ΔPM calculator 58 calculates a difference ΔPM between the required intake pipe pressure PM and the current intake pipe pressure. This difference ΔPM is the required change amount of the intake pipe pressure.

  Downstream of the ΔPM calculation unit 58, calculation elements 60, 62, and 64 for converting the required intake pipe pressure change amount ΔPM into an air amount are arranged. The linear gain setting unit 62 determines the value of the linear gain from the value of the fixed gain processing unit 60, the linear gain processing unit 64, and the required intake pipe pressure change amount ΔPM. The required air amount change amount ΔKL is calculated by multiplying the required intake pipe pressure change amount ΔPM by a fixed gain and further multiplying by a linear gain.

  The required air amount change amount ΔKL converted from the required intake pipe pressure change amount ΔPM is input to the KL calculation unit 66. The KL calculation unit 66 calculates the required intake air amount KL for TA calculation by adding the required air amount change amount ΔKL to the current intake air amount.

  A KL-TA conversion unit 70 is disposed downstream of the KL calculation unit 66 with a filter 68 interposed therebetween. The required intake air amount KL for TA calculation is converted into the required opening degree TA by the KL-TA conversion unit 70. The KL-TA conversion unit 70 converts the required intake air amount KL into the required opening degree TA using a map or a polynomial approximation formula. In the map or polynomial approximate expression, the valve timing of the intake valve and the exhaust valve, the ACIS operating state, the air-fuel ratio, etc. are used as parameters.

  According to the configuration shown in FIG. 2, the maximum value of the required opening degree TA is determined by the value of PMWOT used in the PMWOT guard unit 54. The engine intake amount when the throttle valve opening is controlled to the maximum required opening is the maximum intake amount for control. The value of PMWOT is set so that the maximum intake amount in this control coincides with the true maximum intake amount determined from the structure of the internal combustion engine. In order to determine the value of PMWOT, a test internal combustion engine fit is used.

  Returning to FIG. 1 again, the description of the configuration of the control device of the present embodiment will be continued. The control device of the present embodiment includes a PMWOT value storage unit 26 that stores the value of PMWOT. The value of PMWOT stored in the PMWOT value storage unit 26 is used by the throttle valve opening setting unit 22. The PMWOT value storage unit 26 can not only read the value of PMWOT but also update it.

  By the way, as described above, the value of PMWOT is determined by adaptation using a test internal combustion engine, but there is a manufacturing variation in each internal combustion engine. In addition, the correspondence between the throttle valve opening and the intake air amount may change with time. For this reason, in an actual internal combustion engine, the maximum intake amount on control determined from the value of PMWOT does not always match the maximum intake amount that can be realized by the internal combustion engine. The maximum torque that can be output by the internal combustion engine is realized when the engine intake amount is the maximum intake amount that can be realized by the internal combustion engine. Therefore, when the maximum intake amount for control is less than the maximum intake amount that can be achieved by the internal combustion engine, even if the maximum torque that can be output by the internal combustion engine is required as the required torque, the torque that is actually output is The torque is lower than the maximum torque of the internal combustion engine.

  The control device according to the present embodiment eliminates the deviation between the maximum intake air amount determined from the structure of the internal combustion engine and the maximum intake air amount on the control by learning PMWOT. The learning of PMWOT is performed based on a change in the engine intake air amount when the throttle valve 2 is operated exceeding the regulation by PMWOT. If the PMWOT corresponds to the maximum intake amount that can be realized by the internal combustion engine, the engine intake amount does not change even if the throttle valve 2 is operated beyond the regulation by the PMWOT. However, when the engine intake air amount corresponding to PMWOT is less than the maximum intake air amount that can be realized by the internal combustion engine, the engine intake air amount is increased by operating the throttle valve 2 exceeding the regulation by PMWOT. In this case, the true maximum intake air amount is when the engine intake air amount does not change even if the throttle valve 2 is opened further, and the valve opening at that time is the true maximum opening amount for realizing the maximum torque. It becomes. The control device of the present embodiment learns the value of PMWOT corresponding to the true maximum opening, and stores the learned value in the PMWOT value storage unit 26.

  In order to perform learning of PMWOT, the control device of the present embodiment has acquired a learning start determination unit 30 that determines the start of learning, an intake air amount change information acquisition unit 32 that acquires information regarding changes in the engine intake air amount, and A PMWOT value learning unit 28 for learning PMWOT based on the intake air amount change information is provided. Further, a valve opening change amount setting unit 34 is provided as a function for operating the throttle valve 2 beyond the regulation by PMWOT. Hereinafter, the function of each element related to PMWOT learning will be described.

  The learning start determination unit 30 compares the required torque acquired by the required torque acquisition unit 20 with the maximum torque that can be output by the internal combustion engine. When the required torque is equal to or greater than the maximum torque, the PMWOT learning start is declared when a learning condition described below is satisfied.

The learning start determination unit 30 determines that the learning condition is satisfied when both of the following conditions 1A and 1B are satisfied.
Condition 1A: The amount of change in engine speed per unit time is smaller than a predetermined threshold value.
Condition 1B: The amount of change in required torque per unit time is smaller than a predetermined threshold value.
These conditions 1A and 1B are conditions for confirming that the internal combustion engine is in a steady state. The reason that the learning condition is that the internal combustion engine is in a steady state is to eliminate the influence of the transient fluctuation of the intake air amount on the learning result.

Further, the learning start determination unit 30 determines that the learning condition is satisfied when the following condition 2 is satisfied in addition to when the above conditions 1A and 1B are satisfied.
Condition 2: The service terminal is turned on This case corresponds to the case where the internal combustion engine is maintained at a maintenance factory or the like. When the diagnosis device is connected to the control device and the service terminal is turned on via the diagnosis device, the learning start determination unit 30 determines that learning of PMWOT is possible.

  The determination result by the learning start determination unit 30 is that the valve opening change amount setting unit 34 supplied to the valve opening change amount setting unit 34 is the required opening when the learning start determination unit 30 declares learning start. Is input to the throttle valve control unit 24. When the valve opening change amount is input, the throttle valve control unit 24 operates the throttle valve 2 by exceeding the maximum required opening by the valve opening change amount. Details of the method for setting the valve opening change amount will be described later.

  The determination result by the learning start determination unit 30 is also supplied to the PMWOT value learning unit 28. The PMWOT value learning unit 28 starts learning of PMWOT when the learning start determination unit 30 declares learning start. The intake air amount change information acquired by the intake air amount change information acquisition unit 32 is used for PMWOT learning. The intake air amount change information acquisition unit 32 receives a signal from the air flow sensor 12 disposed in the intake passage, and obtains intake air amount change information from the signal. In addition, the amount of change in valve opening when the throttle valve 2 operates exceeding the maximum required opening in the learning mode is also used for learning PMWOT. The PMWOT value learning unit 28 calculates the learning update amount of the PMWOT, and updates the value of the PMWOT stored in the PMWOT value storage unit 26 with the learning update amount. Details of the PMWOT learning update amount calculation method will be described later.

  FIG. 3 is a flowchart showing a routine of throttle valve opening control executed by the control device of the present embodiment. This routine includes processing related to the above-described PMWOT learning. Hereinafter, the PMWOT learning method will be described in detail with reference to the flowchart of FIG.

In the first step S <b> 2 of the routine shown in FIG. 3, the required torque is acquired by the required torque acquisition unit 20. The demand opening TA _O is calculated in the throttle valve degree of opening setting unit 22 based on the required torque.

In the next step S4, the learning start determination unit 30 first determines whether or not the required torque is equal to or greater than the maximum torque. Further, the learning start determination unit 30 determines whether or not a learning condition is satisfied. If the required torque is smaller than the maximum torque or if the learning condition is not satisfied, the process proceeds to step S14. In step S14, the control of the throttle valve 2 based on the demand opening TA _O by the throttle valve control unit 24 is performed.

If all the conditions for starting learning are satisfied in step S4, PMWOT learning is started. In this case, demand opening TA _O calculated in step S2 is adapted to the maximum demand opening corresponding to the value of Pmwot.

First, in step S6, it is set in the valve opening change amount setting unit 34 valve opening degree change amount ΔTA is added to the maximum demand opening TA _O. The value obtained by adding the valve opening degree change amount ΔTA the maximum demand opening TA _O is the learning opening TA _N for learning Pmwot. In the next step S8, the control of the throttle valve 2 based on the learning degree TA _N by the throttle valve control unit 24 is performed.

In step S10, the intake air amount change information acquisition unit 32 determines whether there is a change in the intake air amount. If the intake air amount is increased when operating the throttle valve 2 exceeds the maximum demand opening TA _O, true maximum opening intake air amount is maximum is greater valve opening than the maximum demand opening TA _O It is understood that it is degree. Continue to greatly gradually opening degree variation ΔTA to the maximum demand opening TA _O to change the intake air amount is eliminated by obtaining the valve opening degree of when a change has gone intake air amount, the maximum intake quantity The true maximum opening can be found.

  Therefore, if the result of determination in step S10 is that there is a change in the intake air amount, processing returns to step S6 again and steps S6 and S8 are performed. Then, the processes in steps S6 to S10 are repeatedly executed until it is determined in step S10 that there is no change in the intake air amount. The valve opening change amount ΔTA set in step S6 is calculated from a map using the number of repetitions and the engine speed as parameters. The valve opening change amount ΔTA is set to a larger value according to the number of repetitions of step S6.

If it is determined in step S10 that there is no change in the intake air amount, the process proceeds to step S12. In step S12, the PMWOT learning unit 28 calculates the PMWOT learning update amount. The PMWOT value learning unit 28 calculates the torque change amount ΔTQ from the change amount of the intake air amount acquired by the intake air amount change information acquisition unit 32. Then, the ratio (ΔTQ / ΔTA) of the torque change amount ΔTQ and the valve opening change amount ΔTA is calculated, and the learning update amount of PMWOT is calculated from a map using the engine speed and ΔTQ / ΔTA as parameters. By this learning update amount is added to the value of PMWOT stored in PMWOT value storage unit 26, the value of PMWOT as the throttle valve opening corresponding to the maximum torque becomes the current throttle valve opening TA _N Will be changed.

  FIG. 4 is a diagram for explaining the effect when the routine of throttle valve opening control shown in FIG. 3 is executed. The broken line in FIG. 4 shows the torque output characteristic with respect to the throttle valve opening obtained by the adaptation using the test internal combustion engine. According to this output characteristic, the throttle valve opening for outputting the maximum torque to the internal combustion engine is TA1. The value of PMWOT at the time of line off is set to a value corresponding to the maximum opening degree TA1. However, due to manufacturing variations and changes over time of the internal combustion engine, the torque output characteristic with respect to the actual throttle valve opening may be an output characteristic as shown by a solid line in FIG. In this case, even if the throttle valve opening is set to the maximum opening TA1, the maximum torque cannot be output to the internal combustion engine.

  According to the control apparatus of the present embodiment, the true maximum opening degree TA2 for outputting the maximum torque is found by executing the throttle valve opening degree control routine shown in FIG. 3, and the value of PMWOT is set to the maximum opening degree. Updated to a value corresponding to degree TA2. As a result, it is possible to accurately realize the valve opening degree that maximizes the engine intake air amount regardless of manufacturing variations and changes with time of the internal combustion engine. That is, according to the control device of the present embodiment, it is possible to ensure the output of the maximum torque regardless of the manufacturing variation of the internal combustion engine and the change with time.

  The control device as the first embodiment of the present invention has been described above. The correspondence relationship between the first embodiment and the present invention is as follows.

  In the configuration shown in FIG. 1, the PMWOT value storage unit 26 corresponds to the “maximum opening degree storage means” of the first invention. The required torque acquisition unit 20 corresponds to the “required torque acquisition means” of the first invention. The throttle valve opening setting unit 22 corresponds to the “valve opening setting means” of the first invention. The throttle valve control unit 24, the learning start determination unit 30, and the valve opening change amount setting unit 34 constitute “valve control means” of the first, second, and third inventions. The intake air amount change information acquisition unit 32 corresponds to the “intake air amount change information acquisition means” of the first invention. The PMWOT value learning unit 28 corresponds to the “maximum opening degree learning means” of the first invention.

Embodiment 2. FIG.
Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 5 is a block diagram showing the configuration of the control device for the internal combustion engine as the second embodiment of the present invention. The control device according to the present embodiment has a configuration in which elements for air-fuel ratio control are added to the configuration of the control device according to the first embodiment. As elements for air-fuel ratio control, the control device of the present embodiment includes an air-fuel ratio information acquisition unit 40, an estimated intake air amount calculation unit 42, and an air-fuel ratio F / B control unit 44. The functions of these elements will be described below. In the configuration shown in FIG. 5, elements that are the same as those in the first embodiment are given the same reference numerals.

  Air-fuel ratio information for air-fuel ratio control is acquired by the air-fuel ratio information acquisition unit 40. A signal from the A / F sensor 16 is input to the air-fuel ratio information acquisition unit 40. The A / F sensor 16 is a sensor disposed in the exhaust passage of the internal combustion engine, and its signal linearly corresponds to a change in the air-fuel ratio of the exhaust gas. The air-fuel ratio information acquisition unit 4 converts the input signal of the A / F sensor 16 into an air-fuel ratio and acquires it as air-fuel ratio information.

  The air-fuel ratio F / B control unit 44 performs feedback correction of the fuel injection amount necessary for realizing the target air-fuel ratio based on the air-fuel ratio information acquired by the air-fuel ratio information acquisition unit 40 and the estimated intake amount of the internal combustion engine. Calculate the amount. Then, the driving time of the fuel injection valve 4 is calculated based on the fuel injection amount reflecting the feedback correction amount.

  The estimated intake air amount of the internal combustion engine is calculated by the estimated intake air amount calculation unit 42. In the process of calculating the estimated intake air amount by the estimated intake air amount calculating unit 42, the value of PMWOT stored in the PMWOT value storage unit 26 is referred to. Hereinafter, the internal configuration of the estimated intake air amount calculation unit 42 will be described. FIG. 6 is a block diagram showing a configuration of the estimated intake air amount calculation unit 42.

  Explaining from the upstream side of the signal in FIG. 6, a ΔTA calculation unit 80 for calculating a deviation ΔTA between the target value (TA target) of the throttle valve opening and the current value (current TA) is arranged at the most upstream side. Yes. The TA target can use a calculated value inside the controller. The current TA can be measured by a throttle opening sensor (not shown).

  Next to the ΔTA calculation unit 80, a ΔTA-ΔPM conversion unit 82 is arranged. The valve opening deviation ΔTA obtained by the ΔTA calculation unit 80 is converted into an intake pipe pressure change amount ΔPM by the ΔTA-ΔPM conversion unit 82. The ΔTA-ΔPM conversion unit 82 converts the valve opening degree deviation ΔTA into the intake pipe pressure change amount ΔPM using a map or a polynomial approximate expression. In the map or polynomial approximate expression, the valve timing of the intake valve and the exhaust valve, the ACIS operating state, the air-fuel ratio, etc. are used as parameters.

  Next to the ΔTA-ΔPM converter 82, a PM calculator 84 is arranged. In the PM calculator 84, the valve opening deviation ΔTA obtained by the ΔTA-ΔPM converter 82 is integrated, and the integrated value is output as the estimated intake pipe pressure PM.

  Next to the PM calculating unit 84, a PMWOT guard unit 86 is arranged. The PMWOT guard unit 86 limits the value of the estimated intake pipe pressure PM obtained by the PM calculation unit 84 by PMWOT, which is an upper limit guard value. In this PMWOT guard unit 86, the value of PMWOT stored in the PMWOT value storage unit 26 (see FIG. 5) is used. When the value of PMWOT is updated by the above learning, the value of PMWOT used by the PMWOT guard unit 86 is also updated.

  Next to the PMWOT guard unit 86, a PM-KL conversion unit 88 is arranged. The estimated intake pipe pressure PM subjected to the guard process by the PMWOT guard unit 86 is converted into the estimated intake air amount KL by the PM-KL conversion unit 88. The PM-KL conversion unit 88 converts the estimated intake pipe pressure PM into the estimated intake air amount KL using a map or a polynomial approximate expression. In the map or polynomial approximate expression, the valve timing of the intake valve and the exhaust valve, the ACIS operating state, the air-fuel ratio, etc. are used as parameters.

  As described above, according to the control device of the present embodiment, the learned value of PMWOT is also reflected in the calculation of the estimated intake air amount. As a result, the accuracy of the estimated intake air amount in a high load region where the throttle valve opening is close to the maximum opening can be increased, and consequently the accuracy of realizing the target air-fuel ratio can be increased.

  Returning to FIG. 5 again, the description of the configuration of the control device of the present embodiment will be continued. The control device of the present embodiment is also characterized by the function of the intake air amount change information acquisition unit 36. In addition to the signal from the airflow sensor 12, a signal from the A / F sensor 16 is input to the intake air amount change information acquisition unit 36. The feedback correction amount calculated inside the air-fuel ratio F / B control unit 44 is also input to the intake air amount change information acquisition unit 36. In the present embodiment, a change amount of the intake air amount is calculated based on the input information.

  FIG. 7 is a flowchart showing a routine executed in the intake air amount change information acquisition unit 36. In the first step S20, it is determined whether air-fuel ratio feedback control is being performed by the air-fuel ratio F / B control unit 44. If air-fuel ratio feedback control is being performed, the process of step S22 is performed. If air-fuel ratio feedback control is not being performed, the process of step S24 is performed.

  In step S22, the intake air amount change amount is calculated from the feedback correction amount calculated inside the air-fuel ratio F / B control unit 44. In this calculation of the intake air amount change amount, a map using the target air-fuel ratio and the feedback correction amount as parameters is used. Map the calculated value obtained by applying the target air-fuel ratio and feedback correction amount to the map when the throttle valve opening is the maximum required opening, and the target air-fuel ratio and feedback correction amount after changing the throttle valve opening on the map The difference from the calculated value obtained by fitting is calculated as the intake air amount change amount. However, there is a time delay before the change in the intake air amount appears in the change in the feedback correction amount. For this reason, the calculation is performed after a certain time has elapsed since the throttle valve 2 was operated. The fixed time is set according to the engine speed.

  In step S24, the intake air amount change amount is calculated from the signal of the A / F sensor 16. A map using the target air-fuel ratio and the signal of the A / F sensor 16 as parameters is used for calculating the intake air amount change here. A calculated value obtained by applying the target air-fuel ratio and A / F sensor signal when the throttle valve opening is the maximum required opening to the map, and the target air-fuel ratio and A / F sensor after changing the throttle valve opening The difference from the calculated value obtained by applying the signal to the map is calculated as the intake air amount change amount. However, since there is a time delay until the change in the intake air amount appears in the signal of the A / F sensor 16, the above calculation is performed after a certain time has elapsed since the throttle valve 2 was operated. Also in this case, the fixed time is set according to the engine speed.

  Following step S22 or S24, step S26 is performed. In step S26, the intake air amount change amount is calculated from the signal of the air flow sensor 12. The change amount of the signal of the air flow sensor 12 directly corresponds to the change amount of the intake air amount.

  In the next step S28, an average value of the intake air amount change amount calculated in step S22 or S24 and the intake air amount change amount calculated in step S26 is calculated. The average value is output to the PMWOT value learning unit 28 as a learning intake air amount change amount.

  As described above, in the control device of the present embodiment, the learning intake air amount change amount is calculated using not only the airflow sensor 12 disposed in the intake system but also the A / F sensor 16 disposed in the exhaust system. Is done. According to this, PMWOT can be learned even if an abnormality occurs in any one of the sensors. That is, robustness against sensor failure can be improved.

  The control apparatus as the second embodiment of the present invention has been described above. In the configuration shown in FIG. 7, the air-fuel ratio F / B control unit 44 corresponds to the “feedback control means” of the sixth invention. The intake air amount change information acquisition unit 36 corresponds to the “intake air amount change information acquisition means” of the fourth, fifth and sixth inventions. The other correspondence relationship between the second embodiment and the present invention is common to the correspondence relationship between the first embodiment and the present invention.

Others.
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the following modifications may be made.

  In the above-described embodiment, the maximum opening of the throttle valve is indirectly learned by learning the value of PMWOT, but the maximum opening of the throttle valve can also be learned directly.

In the case of an internal combustion engine equipped with an intake pipe pressure sensor, the intake air amount change amount may be calculated from the signal of the intake pipe pressure sensor. Further, in the case of an internal combustion engine including a so-called O ₂ sensor instead of the A / F sensor, the intake air amount change amount may be calculated from the signal of the O ₂ sensor.

  In the above-described embodiment, the internal combustion engine provided with the throttle valve is the control target, but the internal combustion engine that can be controlled by the control device of the present invention is not limited to this. The throttle valve is an example of an intake air amount adjusting valve that adjusts the engine intake air amount, and the intake air amount adjusting valve may be an intake valve having a continuous VVL that can continuously change the lift amount. In this case, the maximum opening means the maximum lift amount or the maximum operating angle.

It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 1 of this invention. It is a block diagram which shows the detailed structure of the throttle valve opening degree setting part concerning Embodiment 1 of this invention. It is a flowchart which shows the routine of throttle valve opening degree control performed in Embodiment 1 of this invention. It is a figure for demonstrating the effect when the routine shown in FIG. 3 is performed. It is a block diagram which shows the structure of the control apparatus of the internal combustion engine as Embodiment 2 of this invention. It is a block diagram which shows the detailed structure of the estimated intake air amount calculation part concerning Embodiment 2 of this invention. It is a flowchart which shows the routine for calculation of the intake air amount variation | change_quantity performed in Embodiment 2 of this invention.

Explanation of symbols

2 throttle valve 4 fuel injection valve 10 accelerator opening sensor 12 air flow sensor 14 engine speed sensor 16 A / F sensor 20 required torque acquisition unit 22 throttle valve opening setting unit 24 throttle valve control unit 26 PMWOT value storage unit 28 PMWOT value Learning unit 30 Learning start determination unit 32, 36 Intake amount change information acquisition unit 34 Valve opening change amount setting unit 40 Air-fuel ratio information acquisition unit 42 Estimated intake amount calculation unit 44 Air-fuel ratio F / B control unit

Claims (6)

In a control device for an internal combustion engine provided with an intake air amount adjustment valve for adjusting an engine intake air amount,
Maximum opening degree storage means for storing the valve opening degree of the intake amount adjustment valve when the engine intake amount becomes maximum as the maximum opening degree of the intake amount adjustment valve;
Request torque acquisition means for acquiring a request torque to the internal combustion engine;
Valve opening setting means for setting the valve opening of the intake air amount adjustment valve to the maximum opening when the required torque is equal to or greater than the maximum torque that can be output by the internal combustion engine;
Valve control means for operating the intake air amount adjustment valve so as to change the valve opening from the maximum opening when the valve opening of the intake air amount adjusting valve is set to the maximum opening;
An intake air amount change information acquisition means for acquiring information related to a change in the engine intake air amount when the valve opening of the intake air amount adjustment valve changes from the maximum opening (hereinafter referred to as intake air amount change information);
Maximum opening learning means for learning the maximum opening based on the intake air amount change information;
A control device for an internal combustion engine, comprising:   2. The control device for an internal combustion engine according to claim 1, wherein the valve control means changes the valve opening of the intake air amount adjustment valve from the maximum opening when the internal combustion engine is in a steady state.   The control apparatus for an internal combustion engine according to claim 1 or 2, wherein the valve control means gradually increases the valve opening of the intake air amount adjustment valve with respect to the maximum opening.   The intake air amount change information acquisition means acquires the intake air amount change information using a sensor disposed in an intake system of the internal combustion engine and a sensor disposed in an exhaust system of the internal combustion engine. The control device for an internal combustion engine according to any one of claims 1 to 3. The internal combustion engine is an internal combustion engine having an air-fuel ratio sensor in an exhaust system,
The control apparatus for an internal combustion engine according to any one of claims 1 to 3, wherein the intake air amount change information acquisition means acquires a signal from the air-fuel ratio sensor as the intake air amount change information. The internal combustion engine is an internal combustion engine having an air-fuel ratio sensor in an exhaust system,
Feedback control means for performing feedback control of the fuel supply amount so that the air-fuel ratio of the exhaust gas becomes a predetermined air-fuel ratio based on the signal of the air-fuel ratio sensor,
The control apparatus for an internal combustion engine according to any one of claims 1 to 3, wherein the intake air amount change information acquisition means acquires a feedback correction amount related to the feedback control as the intake air amount change information.

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