JP2007303307A - Internal combustion engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make difference between estimated intake air quantity and actual intake air quantity small without making an internal combustion engine unstable even under a condition where operation stability during cold idling operation drops. <P>SOLUTION: When the operation condition of the internal combustion engine is in a quasi-stable range (yes in step S130) even in a stable range, quasi-stable time intake air correction quantity (ΔGA) is calculated (S132 to S146) and difference between the target intake air quantity and the actual intake quantity is made small by correcting target throttle opening. Since quasi-stable time intake air correction quantity (ΔGA) is established as an inhibited value having lower accuracy than intake air correction quantity required in stable time, the internal combustion engine is not made unstable and a problem is solved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an internal combustion engine controller that controls an intake air amount during idling of an internal combustion engine.

  2. Description of the Related Art An internal combustion engine idle speed control device that performs catalyst temperature increase control for warming up a catalyst prior to idle speed feedback control by adjusting the intake air amount during idle operation of the internal combustion engine is known (for example, Patent Document 1). reference).

  In such control during catalyst warm-up, the opening degree of the electronically controlled throttle valve and idle speed control valve (ISCV) is set to be the intake air amount required for catalyst warm-up. However, there is actually an error between the valve opening and the estimated intake air amount (target intake air amount). For this reason, it is necessary to compare the target intake air amount that is the basis of the valve opening and the intake air amount actually measured by the intake air sensor, and to correct the valve opening when there is a difference.

In such correction, it is necessary to obtain a highly accurate correction amount from the viewpoint of ensuring the stability of the internal combustion engine. Therefore, the difference is obtained from data measured when the operation of the internal combustion engine is stable.
Japanese Patent Laying-Open No. 2004-100529 (page 8, FIG. 4)

  However, there are cases where stable internal combustion engine operation cannot be obtained early during idle operation. For example, there is a case where the fluctuation of the internal combustion engine speed is large, such as when heavy fuel is used as the fuel or when a load such as an air conditioner or power steering occurs. In such an operating state, the difference between the target intake air amount and the actual intake air amount cannot be obtained with high accuracy due to intake air pulsation. If the valve opening is corrected with such low-precision difference data, the difference cannot be reduced, but may be corrected in the direction of increasing, which may further destabilize the internal combustion engine. . In this way, if there is a large difference between the target intake air amount and the actual intake air amount, this difference may not be eliminated early.

  If the intake air shortage continues, the warm-up performance deteriorates.On the contrary, if the intake air intake continues excessively, the internal combustion engine speed becomes excessive and fuel consumption deteriorates or the engine speed increases. To do. In this way, problems in idle operation stability occur.

  The present invention reduces the difference between the target intake air amount and the actual intake air amount without destabilizing the internal combustion engine even when the operation stability is lowered as described above when the intake air amount is controlled during idle operation. It is for the purpose.

In the following, means for achieving the above object and its effects are described.
The internal combustion engine control apparatus according to claim 1 is an internal combustion engine control apparatus that controls an intake air amount during idle operation of the internal combustion engine, the idle operation stability detecting means for detecting operation stability in the idle operation, and the idle engine Stability determination means for determining whether or not the driving stability detected by the driving stability detection means is within a stable range; and the stability determination means determines that the driving stability is within the stable range. The difference between the actual intake air amount and the target intake air amount is obtained during a certain period, and the stable intake correction amount calculating means for calculating the stable intake correction amount according to the difference is detected by the idle operation stability detecting means. Metastable determination means for determining whether or not the operation stability is within a metastable range set in a range wider than the stability range, and the operation stability is determined by the metastability determination means Determined to be within range The difference between the actual intake air amount and the target intake air amount is calculated during the specified period, and the metastable intake air correction amount corresponding to the difference is calculated to be lower than that in the stable air intake correction amount. An intake air correction amount calculating means; an intake air adjustment amount correcting means for correcting an adjustment amount in the intake air amount adjusting mechanism based on an intake air correction amount that has been calculated out of the stable air intake correction amount and the metastable intake air correction amount; It is provided with.

  If the means for calculating the intake air correction amount at the time of functioning is functioning, it will be highly accurate depending on the difference between the actual intake air amount and the target intake air amount obtained during the period when the operating state of the internal combustion engine is within a sufficiently stable stable range. A stable intake correction amount can be calculated. Therefore, the internal combustion engine is not destabilized by using the stable intake correction amount.

  However, even if the operating state of the internal combustion engine is not within the stable range, if the operating state of the internal combustion engine is within the metastable range, the metastable intake correction amount calculating means calculates the metastable intake correction amount, The intake air adjustment amount correction means uses the stable intake air correction amount to reduce the difference between the target intake air amount and the actual intake air amount. In consideration of the calculation in the metastable state, the metastable intake correction amount is set as a value that is suppressed as compared with the stable intake correction amount obtained for the same difference value. Therefore, the metastable intake correction amount is set as a value that is suppressed even if the accuracy is lower than the stable intake correction amount. Even if the process of reducing the difference between the target intake air amount and the actual intake air amount is used, the internal combustion engine is not destabilized.

  The intake air adjustment amount correction means corrects the adjustment amount in the intake air amount adjustment mechanism with the intake air correction amount that has been calculated within the stable intake air correction amount and the metastable intake air correction amount having such properties. Therefore, if the air pressure is within the stable range, and if it is within the stable range, but within the metastable range, the adjustment of the intake air amount adjustment mechanism can be corrected, and the internal combustion engine is disabled by this adjustment amount correction. Do not stabilize. Therefore, the adjustment amount can be corrected at an early stage, and stabilization of the internal combustion engine can be promoted.

  As described above, even when a deviation occurs between the actual intake air amount and the target intake air amount and the operation stability during the idling operation is lowered, the target intake air amount and the actual intake air amount are not destabilized without destabilizing the internal combustion engine. The difference from the amount can be reduced.

  An internal combustion engine control apparatus according to a second aspect is characterized in that, in the first aspect, the stable range and the metastable range are set as a fluctuation range of the internal combustion engine speed or the target intake air amount.

  By setting the stable range and the metastable range in this manner, it is possible to easily detect the operation stability during idling operation based on the internal combustion engine speed or the target intake air amount and determine whether it is within the stable range or the metastable range. Can be determined.

  According to a third aspect of the present invention, in the internal combustion engine control apparatus according to the first or second aspect, the intake air adjustment amount correction means corrects the adjustment amount of the intake air amount adjustment mechanism with the intake air correction amount. Is divided into a plurality of times, and the adjustment amount of the intake air amount adjustment mechanism is corrected stepwise at intervals.

  Even if the intake adjustment amount correction means corrects the adjustment amount of the intake amount adjustment mechanism by either the stable intake correction amount or the metastable intake correction amount, these intake correction amounts may be large. For this reason, the intake air adjustment amount correction means does not immediately correct the adjustment amount of the intake air amount adjustment mechanism by the intake air correction amount itself, but is divided into a plurality of times at intervals and stepwise. It is preferable to correct the adjustment amount.

  As a result, the intake air amount is prevented from changing abruptly, and the instability of the internal combustion engine speed, such as overshoot, can be prevented, whereby the operational stability of the internal combustion engine can be more reliably maintained. .

  The internal combustion engine control apparatus according to claim 4, wherein the metastable intake correction amount calculation means suppresses the metastable intake correction amount as the operation stability is lower. It is characterized by strengthening.

  Even within the metastable range, there is a difference in operational stability. For this reason, by increasing the suppression of the metastable intake correction amount as the operation stability is lower, it becomes easier to maintain the operation stability of the internal combustion engine even if the obtained metastable intake correction amount is used.

  The internal combustion engine control device according to claim 5 is characterized in that in any one of claims 1 to 4, the internal combustion engine speed is controlled to a target rotational speed by adjusting an ignition timing of the internal combustion engine. .

During such intake air amount control, the internal combustion engine speed is controlled to the target speed by adjusting the ignition timing, whereby a more stable internal combustion engine operation can be realized.
The internal combustion engine control apparatus according to claim 6, wherein the metastable intake correction amount calculation unit according to claim 5 is configured to increase the absolute value of the difference between the actual internal combustion engine speed and the target speed. It is characterized by weakening suppression of the metastable intake correction amount.

  In a state where the absolute value of the difference between the actual internal combustion engine speed and the target speed is large, it is considered that the degree of intake / excess amount greatly affects the speed. At this time, if the metastable intake correction amount is used for adjustment of the intake amount adjustment mechanism, the intake amount will be optimized earlier if the suppression is weakened, and the engine speed will be the target speed. Therefore, it is easier to ensure the operational stability of the internal combustion engine.

  According to a seventh aspect of the present invention, in the internal combustion engine control device according to the fifth or sixth aspect, the metastable intake correction amount calculation means suppresses the metastable intake correction amount as the ignition timing adjustment amount increases. It is characterized by weakening.

  In a situation where the rotational speed of the internal combustion engine is adjusted by adjusting the ignition timing, the intake air amount increases or decreases separately from the adjustment amount by the intake air amount adjustment mechanism. Accordingly, in consideration of the case where there is an influence on the intake air amount by adjusting the ignition timing, the more appropriate the intake air correction, the more the adjustment amount of the ignition timing is larger, the more the suppression of the metastable intake air correction amount is weakened. This further facilitates ensuring the operational stability of the internal combustion engine.

  The internal combustion engine control apparatus according to claim 8, wherein, in any one of claims 1 to 7, the plurality of metastability determining means and the metastable intake correction amount calculating means having different metastable ranges. The combination is provided.

  That is, not only one metastable range but also a plurality of metastable ranges having different widths are provided, and a metastability determination means and a metastable intake correction amount calculation means are provided corresponding to each metastable range. It may be provided. This makes it possible to correct the adjustment amount at an early stage and increase the possibility of promoting the stabilization of the internal combustion engine.

[Embodiment 1]
FIG. 1 shows a schematic configuration diagram of an internal combustion engine (a gasoline engine in the present embodiment) 2 mounted on a vehicle and an electronic control unit (hereinafter referred to as “ECU”) 4 as an internal combustion engine control device. . The internal combustion engine 2 is a four-cylinder internal combustion engine here, but only one cylinder is shown in a longitudinal sectional view in FIG. The number of cylinders may be another number of cylinders, for example, 3 cylinders, 6 cylinders, or 8 cylinders. In the figure, one intake valve 2a and one exhaust valve 2b are shown for each cylinder, but a 4-valve internal combustion engine or a 5-valve internal combustion engine may be used.

  The output of the internal combustion engine 2 is finally transmitted as traveling driving force to the wheels via the transmission. The internal combustion engine 2 is provided with a spark plug 14 that ignites the air-fuel mixture in the combustion chamber 10. The combustion chamber 10 is provided with an intake port 16 that is opened and closed by an intake valve 2 a, and a fuel injection valve 12 that injects fuel toward the intake port 16 in the middle of each intake passage 20 connected to the intake port 16. Is provided for each cylinder. The intake passage 20 is connected to a surge tank 22, and a throttle valve 26 (corresponding to an intake air amount adjusting mechanism) whose opening degree is adjusted by a motor 24 is provided on the upstream side of the surge tank 22. The intake air amount GA is adjusted by the opening of the throttle valve 26 (throttle opening TA). The throttle opening degree TA is detected by the throttle opening degree sensor 28 and read into the ECU 4. The intake air amount GA is detected by an intake air amount sensor 30 provided on the upstream side of the throttle valve 26 and read into the ECU 4. The fuel injection valve 12 may be an in-cylinder injection type gasoline engine that directly injects fuel into the combustion chamber 10.

  Further, the combustion chamber 10 is provided with an exhaust port 32 that is opened and closed by the exhaust valve 2 b, and a catalytic converter 38 is disposed in the middle of the exhaust passage 36 connected to the exhaust port 32. A three-way catalyst as an exhaust purification catalyst is disposed in the catalytic converter 38. An air-fuel ratio sensor 40 that outputs a signal corresponding to the exhaust air-fuel ratio AF is disposed in the exhaust passage 36 upstream of the catalytic converter 38.

  The ECU 4 is an internal combustion engine control circuit configured mainly with a digital computer. The ECU 4 inputs signals from sensors that detect the operating state of the internal combustion engine 2 in addition to the throttle opening sensor 28, the intake air amount sensor 30, and the air-fuel ratio sensor 40 described above. That is, an accelerator opening sensor 48 that detects the amount of depression of the accelerator pedal 46 (accelerator opening ACCP), an internal combustion engine speed sensor 50 that detects the internal combustion engine speed NE from the rotation of the crankshaft, and the rotational phase of the intake camshaft. A signal is input from a reference crank angle sensor 52 that determines a reference crank angle. Further, a signal is also input from the coolant temperature sensor 54 for detecting the coolant temperature THW of the internal combustion engine. Further, a signal representing the intake air temperature THA is input from the intake air temperature sensor 56 disposed in the air cleaner at the tip of the intake passage 20, and the outside air temperature THZ is represented from the outside air temperature sensor 58 provided at the indoor air intake port of the air conditioner AC. A signal is input, and a signal representing the exhaust temperature THEx is input from the exhaust temperature sensor 60 downstream of the catalytic converter 38. In addition to such sensors, various sensors are provided as necessary.

  The ECU 4 controls the fuel injection timing, the fuel injection amount, the ignition timing, and the intake air of the internal combustion engine 2 by a control signal for the fuel injection valve 12, the ignition plug 14, or the throttle valve motor 24 based on the detection contents from each sensor described above. Adjust the amount. The fuel injection amount is feedback-controlled by the output of the air-fuel ratio sensor 40 so as to achieve the target air-fuel ratio, here the stoichiometric air-fuel ratio. Further, at the time of idling, the ECU 4 determines the throttle opening of the throttle valve 26 so that the idling target rotational speed NT is set in accordance with the state of the internal combustion engine 2 (cooling water temperature THW, air conditioner load, etc.) especially after the warm-up is completed. Idle speed feedback control is executed by adjusting TA. Note that when the throttle valve 26 is not an electronically controlled throttle, idle speed feedback control may be executed by intake air amount control by ISCV bypassing the throttle valve 26.

  Next, the idle operation control executed by the ECU 4 will be described focusing on the processing executed particularly in the cold state. FIGS. 2 and 3 are flowcharts of the corresponding cold idle operation control process. This process is repeated at a constant crank angle (here, 180 ° CA: CA represents the crank angle) cycle when the internal combustion engine 2 is determined to be idle when it is separately determined by the ECU 4. It is a process to be executed. The steps in the flowchart corresponding to the individual processing contents are represented by “S˜”.

  When this process is started, it is first determined whether or not it is cold (S100). If it is not cold (NO in S100), the first actually measured intake air amount integrated value ΣGAS1 (g / s), the first target intake air amount integrated value ΣGAT1 (g / s), and the first integrated counter CGAS1 are cleared. (S122). Further, the second actually measured intake air amount integrated value ΣGAS2 (g / s), the second target intake air amount integrated value ΣGAT2 (g / s), and the second integrated counter CGAS2 are cleared (S124). Then, the internal combustion engine speed NE detected by the internal combustion engine speed sensor 50 at the current execution cycle is set as the previous internal combustion engine speed value NEold (S126), and the target intake air previous value GISCold is set at the current execution period. The calculated target intake air amount GISC is set (S128). And this control cycle is complete | finished. Here, the target intake air amount GISC is separately set by the ECU 4 by taking into account the intake air amount for warming up the catalyst, the intake air amount for air conditioners, headlamps, and other loads, and further correcting with an intake air correction amount ΔGA as described later. The target intake air amount.

In the cold state, the ECU 4 separately executes a process of controlling the internal combustion engine speed NE to the target speed NT by ignition timing control.
On the other hand, if it is cold (yes in S100), it is determined whether or not the intake air correction amount ΔGA = 0 (S101). This is to determine whether the throttle opening degree TA (actually the target throttle opening degree TAt) has not been corrected by the intake air correction amount ΔGA or that the correction has been completed. Since the intake correction amount ΔGA = 0 at first (yes in S101), it is obtained at the previous execution cycle from the internal combustion engine speed NE obtained at the current execution cycle as shown in Equation 1 below. An internal combustion engine speed fluctuation value ΔNE is obtained by subtracting the internal combustion engine speed previous value NEold (S102).

[Formula 1] ΔNE ← NE − NEold
Next, as shown in Expression 2, the target intake air amount fluctuation value is obtained by subtracting the target intake air amount previous value GISCold obtained during the previous execution cycle from the target intake air amount GISC obtained as described above during the current execution cycle. ΔGISC is obtained (S104).

[Formula 2] ΔGISC ← GISC − GISCold
Next, the absolute value | ΔNE | of the internal combustion engine speed fluctuation value ΔNE is within the stable range (in this case, the range below the stable range upper limit value X1 (rpm)) and the absolute value of the target intake air quantity fluctuation value ΔGISC | ΔGISC It is determined whether or not | is within the stable range (here, a range equal to or lower than the stable range upper limit value Y1 (g / s)) (S106). The state where both of these stable ranges are satisfied is usually when the idling operation state of the internal combustion engine 2 is in a stable state.

  If the logical product condition of | ΔNE | ≦ X1 and | ΔGISC | ≦ Y1 is not satisfied (No in S106), then the logical product condition of | ΔNE | ≦ X2 and | ΔGISC | ≦ Y2 is satisfied. It is determined whether or not it is satisfied (S130). That is, the absolute value | ΔNE | of the internal combustion engine speed fluctuation value ΔNE is within the metastable range (here, the range below the metastable range upper limit value X2 (rpm)) and the absolute value of the target intake air amount fluctuation value ΔGISC | It is determined whether or not ΔGISC | is within a metastable range (here, a range equal to or lower than the metastable range upper limit Y2 (g / s)) (S106). The state in which both metastable ranges are satisfied (yes in S130) is a slightly unstable state as the idling operation state of the internal combustion engine 2 than the state in which both of the two stable ranges are satisfied (yes in S106). It is.

  If the logical product condition of | ΔNE | ≦ X2 and | ΔGISC | ≦ Y2 is not satisfied (No in S130), steps S122 to S128 are executed as described above, and the current control cycle is terminated.

  Therefore, an unstable state in which the internal combustion engine 2 does not enter the metastable range, for example, a state in which the internal combustion engine rotational speed NE or the target intake air amount GISC is greatly changed immediately after the start is completed or immediately after the air conditioner is turned on / off. Then (no in S106, no in S130), the following process for correcting the excess or deficiency of the intake air amount is not performed.

  When the values of the internal combustion engine speed NE and the target intake air amount GISC settle down to some extent after the start is completed, and the logical product condition of | ΔNE | ≦ X2 and | ΔGISC | ≦ Y2 is satisfied (yes in S130), the following expression 3 As shown, the intake air amount GA detected during the current execution cycle is integrated into the second actually measured intake air amount integrated value ΣGAS2 (S132).

[Formula 3] ΣGAS2 ← ΣGAS2 + GA
Next, as shown in Expression 4, the target intake air amount GISC calculated during the current execution cycle is integrated into the second target intake air amount integrated value ΣGAT2 (S134).

[Formula 4] ΣGAT2 ← ΣGAT2 + GISC
Next, the second integration counter CGAS2 is incremented (S136).
Then, it is determined whether or not the second integration counter CGAS2 is less than the specified integration number value n2 (S138). Here, the specified cumulative number value n2 = 3. The value of the specified cumulative number of times n2 may be “1” or “2”, or may be “4” or more.

  If CGAS2 <n2 (yes in S138), then the above steps S126 and S128 are executed, and the current control cycle is terminated. Therefore, as long as it is determined as yes in step S130, integration processing (S132, S134) of the second actually measured intake air amount integrated value ΣGAS2 and the second target intake air amount integrated value ΣGAT2 is executed.

  By repeating such integration processing and incrementing the second integration counter CGAS2 (S136), the second integration counter CGAS2 finally reaches the specified integration count value n2 (no in S138). As a result, as shown in Equation 5, the second actually measured intake air amount integrated value ΣGAS2 is divided by the specified cumulative number of times n2, and the average value of the intake air amount GA within the metastable range (intake air amount average value GAS) is calculated. (S140).

[Formula 5] GAS ← ΣGAS2 / n2
Next, as shown in Expression 6, the second target intake air amount integrated value ΣGAT2 is divided by the specified cumulative number of times n2, and the average value of the target intake air amount GISC within the metastable range (target intake air amount average value GAT) is calculated. (S142).

[Formula 6] GAT ← ΣGAT2 / n2
Next, based on the difference between the intake air amount average value GAS and the target intake air amount average value GAT, an intake air correction amount ΔGA corresponding to the metastable intake air correction amount is calculated as shown in Equation 7 (S144). As will be described later, the intake correction amount ΔGA may be calculated as a stable intake correction amount.

[Formula 7] ΔGA ← Dec (GAS-GAT)
Here, the suppression operator Dec () is an operator that decreases the absolute value of the value in ().
In the present embodiment, a function of Dec (X) = X ± α using the suppression value α is applied. Here, Dec (X) = X−α when X> 0, Dec (X) = X + α when X <0, and Dec (X) = X when X = 0, that is, α = 0. When the suppression value α exceeds the value X, Dec (X) = 0. The suppression value α is set as shown in the map of FIG. 4, and a larger value is set as the absolute value | ΔNE | of the internal combustion engine speed fluctuation value is larger. In place of the absolute value | ΔNE | of the internal combustion engine speed fluctuation value, the absolute value | ΔGISC | of the target intake air quantity fluctuation value may be used as a parameter.

As described above, the value of “GAS-GAT” is not set as it is in the intake correction amount ΔGA at the time of metastable, but is set to be suppressed by the suppression value α.
Then, as shown in Expression 8, a target intake air amount correction amount dGISC calculated in a throttle opening degree control process (FIG. 5) described later is subtracted from the intake air correction amount ΔGA to set a new intake air correction amount ΔGA (S146). ). This target intake air amount correction amount dGISC represents an amount actually used for correction in the intake air correction amount ΔGA obtained by the equation (7).

[Formula 8] ΔGA ← ΔGA − dGISC
When the intake air correction amount ΔGA is calculated in this way, the processes of steps S122 to S128 described above are executed, and the current control cycle is terminated.

  When the intake correction amount ΔGA is newly calculated in this way, it is used for correcting the target intake air amount GISC in the throttle opening control process shown in the flowchart of FIG. The throttle opening control process (FIG. 5) is a process executed at a constant time period or a constant crank angle period.

  When the intake correction amount ΔGA is set in step S146, the intake correction amount ΔGA is reflected in the throttle opening TA in the throttle opening control process (FIG. 5) until the intake correction amount ΔGA = 0. Is determined to be no in step S101 in the cold idle operation control process (FIGS. 2 and 3). This only repeats steps S122 to S128 described above. If ΔGA = 0 is set on the throttle opening control process (FIG. 5) side, the answer is yes in step S101, and the processes in and after step S102 are executed again.

  At this time, when the values of the internal combustion engine speed NE and the target intake air amount GISC are sufficiently settled and the logical product condition of | ΔNE | ≦ X1 and | ΔGISC | ≦ Y1 is satisfied (yes in S106), It is determined that the operating state of the internal combustion engine 2 is within the stable range. As a result, the intake air amount GA detected during the current execution cycle is integrated into the first actually measured intake air amount integrated value ΣGAS1 as shown in Equation 9 (S108).

[Formula 9] ΣGAS1 ← ΣGAS1 + GA
Next, as shown in Expression 10, the target intake air amount GISC calculated during the current execution cycle is integrated into the first target intake air amount integrated value ΣGAT1 (S110).

[Formula 10] ΣGAT1 ← ΣGAT1 + GISC
Next, the first integration counter CGAS1 is incremented (S112).
Then, it is determined whether or not the first integration counter CGAS1 is less than the specified integration number value n1 (S114). Here, the specified cumulative number value n1 = 3. The value of the specified cumulative number of times n1 may be “1” or “2”, or may be “4” or more. Further, it does not have to be the same value as the above-mentioned specified cumulative number value n2.

  If CGAS1 <n1 (yes in S114), then the above steps S126 and S128 are executed to end the current control cycle. Therefore, as long as it is determined as yes in step S106, the integration process of the first actually measured intake air amount integrated value ΣGAS1 and the first target intake air amount integrated value ΣGAT1 is executed in steps S108 and S110.

  By repeating such integration processing and incrementing the first integration counter CGAS1 (S112), the first integration counter CGAS1 reaches the specified integration number value n1 (no in S114). As a result, as shown in equation 11, the first actually measured intake air amount integrated value ΣGAS1 is divided by the specified cumulative number of times n1 to calculate the intake air amount average value GAS that is the average value of the intake air amount GA within the stable range. (S116).

[Formula 11] GAS ← ΣGAS1 / n1
Next, as shown in Expression 12, the first target intake air amount integrated value ΣGAT1 is divided by the specified cumulative number of times n1 to calculate a target intake air amount average value GAT that is an average value of the target intake air amount GISC within the stable range ( S118).

[Formula 12] GAT ← ΣGAT1 / n1
Next, as shown in Expression 13, the difference between the intake air amount average value GAS and the target intake air amount average value GAT itself is calculated as a stable intake air correction amount and set to the intake air correction amount ΔGA (S120).

[Formula 13] ΔGA ← GAS − GAT
Here, Dec () used in step S144 executed in the metastable range is not used. In this way, the value of “GAS-GAT” is set as it is for the intake correction amount ΔGA at the time of stability, and is not suppressed as in the case of metastable.

  Then, as shown in Expression 14, a target intake air amount correction amount dGISC calculated by a throttle opening degree control process (FIG. 5) described later is subtracted from the intake air correction amount ΔGA to newly set as an intake air correction amount ΔGA. (S121). The reason for the subtraction of the target intake air amount correction amount dGISC is the same as that in the case of Equation 8 above.

[Formula 14] ΔGA ← ΔGA−dGISC
When the intake air correction amount ΔGA is calculated in this way, the processes of steps S122 to S128 described above are executed, and the current control cycle is terminated. This intake air correction amount ΔGA is used for correcting the target intake air amount GISC in the throttle opening control process (FIG. 5).

Next, throttle opening control processing (FIG. 5) will be described. As described above, this process is executed at a constant time period or a constant crank angle period.
When this process is started, first, the target intake air amount GISC is calculated based on the internal combustion engine operating load state (S200). In the cold idle operation control process (FIGS. 2 and 3), the variation (S104) of the target intake air amount GISC is determined (S106, S130).

  Next, it is determined whether or not the absolute value | ΔGA | of the intake air correction amount ΔGA obtained in the cold idle operation control process (FIGS. 2 and 3) is larger than the correction unit amount Uga (g / s). (S202). The correction unit amount Uga (> 0) represents the upper limit per time when the target intake air amount GISC is corrected. When correction exceeding the correction unit amount Uga is required, the correction amount is divided into correction unit amounts Uga and used for correction step by step at intervals.

  For example, if the target intake air amount correction amount dGISC and the intake air correction amount ΔGA are both “0” in step S121 or step S146 of the cold idle operation control process (FIGS. 2 and 3), ΔGA = 0 ( g / s). Therefore, | ΔGA | <Uga (no in S202), and it is next determined whether ΔGA ≠ 0 (S210). Here, since the intake correction amount ΔGA = 0 (no in S210), the target throttle opening degree TAt (corresponding to the adjustment amount in the intake air amount adjustment mechanism) is set to the target intake air amount GISC as shown in Expression 15. The value corrected by the intake air amount correction amount dGISC is used to calculate the map or the function fta (S218).

[Formula 15] TAt ← fta (GISC-dGISC)
Then, the throttle valve motor 24 is driven to reach the target throttle opening degree TAt, and the opening degree of the throttle valve 26 is adjusted (S220).

  Consider a case where a value other than “0” is set in the intake air correction amount ΔGA in the cold idling operation control process (FIGS. 2 and 3). In this case, if | ΔGA | ≦ Uga (no in S202) and then ΔGA ≠ 0 (yes in S210), the value of the intake air correction amount ΔGA is set as it is in the correction execution amount dx (S212). ). Then, as shown in Expression 16, the correction execution amount dx is integrated into the target intake air amount correction amount dGISC (S214).

[Formula 16] dGISC ← dGISC + dx
Next, as shown in Expression 17, the correction execution amount dx is subtracted from the intake air correction amount ΔGA (S216).
[Formula 17] ΔGA ← ΔGA − dx
In this case, since the value of the intake air correction amount ΔGA is set as the correction execution amount dx in the immediately preceding step S212, ΔGA = 0 according to the equation 17.

  Then, the target throttle opening degree TAt is obtained in a state where the target intake air amount GISC is corrected by the above equation 15 using the target intake air amount correction amount dGISC integrated by the correction execution amount dx by the above equation 16 (S218). Based on the target throttle opening degree TAt, the opening degree of the throttle valve 26 is adjusted (S220).

  If | ΔGA |> Uga (yes in S202), it is next determined whether or not ΔGA> 0 (S204). If ΔGA> 0 (yes in S204), the correction execution amount dx is set to the correction unit amount Uga (S206). If ΔGA <0 (no in S204), −Uga is set to the correction execution amount dx. It is set (S208).

  Then, the calculation of Expression 16 (S214) and Expression 17 (S216) is executed, the target throttle opening degree TAt is calculated (S218), and the opening degree of the throttle valve 26 is adjusted based on the target throttle opening degree TAt. (S220). That is, the integration for the correction unit amount Uga is made to the target intake air amount correction amount dGISC, so that the correction for the correction unit amount Uga is made to the target intake air amount GISC, and the target throttle opening degree TAt is obtained.

  If | ΔGA |> Uga even in the execution cycle after the subtraction of the correction unit amount Uga is performed on the intake air correction amount ΔGA in step S216 (yes in S202), the processing described above ( Through S204 to S208 and S214 to S220), the integration corresponding to the correction unit amount Uga is performed to the target intake air amount correction amount dGISC. As a result, the correction by the correction unit amount Uga is further strengthened stepwise with an interval (execution cycle) with respect to the target intake air amount GISC, and the target throttle opening degree TAt is calculated by the equation 15. .

  By repeating such processing, if the absolute value | ΔGA | of the intake correction amount ΔGA decreases and becomes | ΔGA | ≦ Uga (no in S202), all the remaining corrections of the intake correction amount ΔGA are corrected as described above. The control is executed for the target intake air amount GISC, and the target throttle opening degree TAt is calculated by the equation 15 (S210 to 220). As a result, the intake air correction amount ΔGA = 0.

  Therefore, in the next execution cycle, no is determined in step S202 and no is determined in step S210, and step S218 is immediately executed. The target intake air amount correction amount dGISC at this time reflects all of the intake air correction amount ΔGA calculated in step S121 or step S146 of the cold idle operation control process (FIGS. 2 and 3).

  Further, since the intake air correction amount ΔGA = 0, it is determined as yes in step S101 of the cold idling operation control process (FIGS. 2 and 3). Therefore, if the stable range (yes in S106) or the metastable range (yes in S130) is reached, the integration of the intake air amount GA to the actually measured intake air amount integrated values ΣGAS1, ΣGAS2 (S108, S132) and the target intake air amount integration again Integration of the target intake air amount GISC to the values ΣGAT1 and ΣGAT2 (S110, S134) is started.

  FIG. 6 is a timing chart showing an example of processing in the present embodiment. Here, immediately after the completion of the start, and in a state where | ΔNE |> X2 (before t1: no in S106, no in S130), the intake air correction amount ΔGA = 0 (initial setting state). Therefore, in the throttle opening control process (FIG. 5), the target intake air amount correction amount dGISC does not increase and remains “0”. Therefore, the target intake air amount GISC is not corrected in the equation (15).

  Thereafter, the metastable range (| ΔGISC | ≦ Y2 and | ΔNE | ≦ X2) is satisfied (t1: yes in S130). As a result, the integration of the second actually measured intake air amount integrated value ΣGAS2 and the second target intake air amount integrated value ΣGAT2 is started (t1 to t3: S132, S134). When the integration is completed (no in S138), average values GAS, GAT of the second actually measured intake air amount integrated value ΣGAS2 and the second target intake air amount integrated value ΣGAT2 are calculated (S140, S142). Then, the difference value between the average values GAS and GAT is set to the intake air correction amount ΔGA by the calculation according to the equation 7 and the subtraction by the current target intake air amount correction amount dGISC (t4: S144, S146). Then, in the throttle opening control process (FIG. 5), the intake correction amount ΔGA is divided into correction unit amounts Uga and sequentially reflected in the target throttle opening TAt by correcting the target intake air amount GISC (t5 to t9). .

  Then, the intake correction amount ΔGA returns to “0”, and it is determined yes in step S101 of the cold idle operation control process (FIGS. 2 and 3). In the example of FIG. 6, at this time, the internal combustion engine 2 is stabilized and is in a stable range (| ΔGISC | ≦ Y1 and | ΔNE | ≦ X1) (immediately after t9: yes in S130). As a result, integration of the first actually measured intake air amount integrated value ΣGAS1 and the first target intake air amount integrated value ΣGAT1 is started (t10 to t12: S108, S110). When the integration is completed (no in S114), average values GAS and GAT of the first actually measured intake air amount integrated value ΣGAS1 and the first target intake air amount integrated value ΣGAT1 are calculated (S116, S118). The value of this difference is not suppressed as in the metastable range, but is subtracted by the current target intake air amount correction amount dGISC and set to the intake air correction amount ΔGA (t13: S120, S121). Then, in the throttle opening control process (FIG. 5), the intake correction amount ΔGA is divided into correction unit amounts Uga, and the target intake air amount GISC is corrected in order and reflected in the target throttle opening TAt. Since the intake correction amount ΔGA <Uga from the beginning, the process is completed once (t14). In the example of FIG. 6, the intake air correction amount ΔGA obtained in step S121 is negative, and the target intake air amount correction amount dGISC is decreased.

  Thereafter, the state returns to the state where the intake correction amount ΔGA = 0, and the integration of the first actually measured intake amount integrated value ΣGAS1 and the first target intake amount integrated value ΣGAT1 is repeated (from t15). However, since the intake correction amount ΔGA calculated in step S121 of the cold idle operation control process (FIGS. 2 and 3) is “0”, the value of the target intake air amount correction amount dGISC does not change. Is maintained.

  In the above-described configuration, the relationship with the claims is that steps S102 and S104 in the cold idle operation control process (FIGS. 2 and 3) are processes as idle operation stability detection means, and step S106 is stability determination means. Steps S108 to S121 correspond to a process as a stable intake correction amount calculation unit. Further, step S130 is a process as a metastability determination means, steps S132 to S146 are a process as a metastable intake correction amount calculation means, and a throttle opening control process (FIG. 5) is a process as an intake adjustment amount correction means. It corresponds to.

According to the first embodiment described above, the following effects can be obtained.
(I). Even if the operation state of the internal combustion engine 2 is not within the stable range (the range determined as yes in step S106), the operation state of the internal combustion engine 2 is within the metastable range (the range determined as yes in step S130). For example, the intake correction amount ΔGA is calculated as the metastable intake correction amount. Then, the difference between the target intake air amount and the actual intake air amount is reduced by correcting the target throttle opening degree TAt using the intake air correction amount ΔGA.

  The intake correction amount ΔGA obtained in this metastable range is calculated by using the above equation for the difference between the intake air amount GA and the target intake air amount GISC (actually, the difference between the average value GAS and the average value GAT). 7 is set as a value that is suppressed from the intake correction amount ΔGA as the stable intake correction amount obtained within the stable range. Therefore, the intake correction amount ΔGA as the metastable intake correction amount is set as a value that is suppressed even if the accuracy is lower than the intake correction amount ΔGA as the stable intake correction amount. Even if correction for reducing the difference between the amount and the actual intake air amount is performed, the internal combustion engine 2 is not destabilized.

  Of the two types of intake correction amounts ΔGA having such properties, the throttle opening degree TA (actually, the target throttle opening amount TAt that is the target value) is corrected by the intake correction amount ΔGA that has been calculated. . Therefore, even if it is not within the stable range, if it falls within the metastable range, the target throttle opening degree TAt can be corrected by the intake correction amount ΔGA as the metastable intake correction amount. Moreover, since the intake correction amount ΔGA is set to a value that is suppressed as compared with the intake correction amount ΔGA obtained within the stable range as described above, the internal combustion engine 2 is not destabilized. For this reason, correction can be made early and the stabilization of the internal combustion engine 2 can be promoted.

  As described above, even when a deviation occurs between the actual intake air amount GA and the target intake air amount GISC and the operation stability in the idling operation of the internal combustion engine 2 is lowered, the target intake air amount is not destabilized without causing the internal combustion engine 2 to become unstable. And the difference between the actual intake air amount can be reduced. As a result, stable operation of the internal combustion engine 2 can be ensured at an early stage during warm-up, and deterioration of fuel consumption, increase in rotational speed, and deterioration of warm-up performance due to excessive or insufficient intake air can be prevented.

  (B). In the throttle opening control process (FIG. 5), if the intake correction amount ΔGA is large, if it is immediately reflected in the target throttle opening TAt, the internal combustion engine 2 will be destabilized, such as overshoot of the rotational speed. There is a fear. For this reason, when the intake correction amount ΔGA is large, here, when it is larger than the correction unit amount Uga, it is reflected in the target throttle opening degree TAt step by step with a plurality of intervals.

As a result, the intake air amount GA is prevented from changing suddenly, the instability of the internal combustion engine speed NE can be prevented, and the operational stability of the internal combustion engine 2 can be more reliably maintained.
(C). As shown in FIG. 4, the suppression value α used in the metastable range increases as the absolute value | ΔNE | of the internal combustion engine speed fluctuation value (or the absolute value | ΔGISC | of the target intake air quantity fluctuation value) increases. The lower the stability, the larger the value, and the stronger the suppression of the intake air correction amount ΔGA. That is, in view of the fact that the lower the operational stability is, the larger the error that appears in the intake air correction amount ΔGA is, so the suppression of the intake air correction amount ΔGA is strengthened. This further facilitates maintaining the operational stability of the internal combustion engine.

(D). When the engine is cold, the internal combustion engine speed NE is controlled to the target speed NT by adjusting the ignition timing, so that a more stable operation of the internal combustion engine 2 can be realized.
[Embodiment 2]
In the present embodiment, the suppression value α used for the suppression operator Dec () is set as shown in FIG. 7 in step S144 of the cold idle operation control process (FIGS. 2 and 3). Here, the fact that the larger the suppression value α is set as the absolute value | ΔNE | of the internal combustion engine speed fluctuation value (or the absolute value | ΔGISC | of the target intake air quantity fluctuation value) is larger is the same as in the case of FIG. The same. However, the smaller the absolute value | NE-NT | of the difference between the internal combustion engine speed NE controlled by the ignition timing and the target speed NT, the larger the increase / decrease in the suppression value α relative to the increase / decrease in | ΔNE | (or | ΔGISC |). However, as | NE−NT | is larger, the increase / decrease in the suppression value α with respect to the increase / decrease in | ΔNE | (or | ΔGISC |) is made smaller. Other configurations are the same as those in the first embodiment.

According to the second embodiment described above, the following effects can be obtained.
(I). In addition to the effects of the first embodiment, the following effects are produced. That is, as shown in FIG. 7, by setting the suppression value α, the intake correction amount ΔGA is not suppressed as the actual internal combustion engine rotational speed NE and the target rotational speed NT are further away.

  In a state where the internal combustion engine rotational speed NE is greatly deviated from the target rotational speed NT, it is considered that the actual intake air amount GA is also largely deviated from the target intake air amount GISC, so that the suppression of the intake air correction amount ΔGA is weakened. This makes it possible to optimize the intake amount at an early stage. As a result, the internal combustion engine rotational speed NE also easily converges to the target rotational speed NT, and it becomes easier to ensure the operational stability of the internal combustion engine.

[Embodiment 3]
In the present embodiment, the suppression value α (calculated from FIGS. 4 and 7) used in step S144 of the cold idle operation control process (FIGS. 2 and 3) in the first embodiment or the second embodiment. ) Is reduced according to the influence of the advance value θ of the ignition timing with respect to the intake air amount as shown in the following (1) to (3).

  (1). When GAS-GAT> 0 and the internal combustion engine rotational speed NE> target rotational speed NT and the advance value θ <0 (ignition timing correction from the steady-time ignition timing to the retarded side), FIG. The return value β (g / s) is obtained from the advance value θ at β (β <0).

  (2). In a state where GAS-GAT <0 and NE <NT and the advance value θ> 0 (ignition timing correction from the steady-state fire timing to the advance side), the advance value θ is determined from FIG. A return value β is determined (β> 0).

(3). Except for the above (1) or (2), the return value β = 0.
The suppression value α is subtracted as shown in Expression 18 by the return value β obtained as described above. However, when the return value β exceeds the suppression value α, the suppression value α = 0.

[Formula 18] α ← α − β
The suppression value α obtained by the equation 18 is used as described in the equation 7.
According to the third embodiment described above, the following effects can be obtained.

(I). In addition to the effects of the first or second embodiment, the following effects are produced.
In a situation where the internal combustion engine rotational speed control is performed by adjusting the ignition timing, the intake air amount GA is increased or decreased by adjusting the rotational speed separately from the adjustment by the throttle valve 26. Thus, if there is an influence on the intake air amount GA by adjusting the ignition timing, it is more appropriate to weaken the suppression by the suppression value α for the intake air correction amount ΔGA obtained as the metastable intake correction amount. Intake correction. Therefore, in the relevant internal combustion engine operating state, the suppression value α is decreased by the return value β as described above, so that appropriate suppression can be performed, and the operational stability of the internal combustion engine 2 can be easily ensured.

[Other embodiments]
(A). In each of the above-described embodiments, the suppression process by the suppression operator Dec () may be performed by multiplication of the suppression coefficient ka (0 <ka <1) with respect to the value of (GAS−GAT) instead of addition / subtraction of the suppression value α. Also for the return value β, the suppression value α may be multiplied by the return coefficient kb (0 <kb <1).

  (B). In the cold idle operation control process (FIGS. 2 and 3), the metastable range (the range determined as yes in step S130) is only one, but the second metastable range having a wider range is set. The intake correction amount ΔGA as the metastable intake correction amount may be obtained by setting. In the second metastable range, the suppression of the intake correction amount ΔGA is strengthened according to the width of the range. Further, one or a plurality of metastable ranges wider than the second metastable range may be provided, and similarly, the suppression of the intake correction amount ΔGA is strengthened according to the range.

  (C). The stability range (FIG. 2: S106) and metastable range (FIG. 3: S130) were determined by | ΔNE | and | ΔGISC |, but were determined by either | ΔNE | or | ΔGISC |. May be.

1 is a schematic configuration diagram of a vehicle-mounted internal combustion engine and an ECU according to a first embodiment. 3 is a flowchart of cold idle operation control processing according to the first embodiment. 3 is a flowchart of cold idle operation control processing according to the first embodiment. FIG. 4 is a configuration explanatory diagram of a map for calculating a suppression value α in the first embodiment. 4 is a flowchart of throttle opening control processing according to the first embodiment. 3 is a timing chart showing an example of control in the first embodiment. FIG. 6 is a configuration explanatory diagram of a map for calculating a suppression value α in the second embodiment. FIG. 10 is a configuration explanatory diagram of a map for calculating a return value β of a suppression value α in the third embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Internal combustion engine, 2a ... Intake valve, 2b ... Exhaust valve, 4 ... ECU, 10 ... Combustion chamber, 12 ... Fuel injection valve, 14 ... Spark plug, 16 ... Intake port, 20 ... Intake passage, 22 ... Surge tank, DESCRIPTION OF SYMBOLS 24 ... Motor for throttle valves, 26 ... Throttle valve, 28 ... Throttle opening sensor, 30 ... Intake amount sensor, 32 ... Exhaust port, 36 ... Exhaust passage, 38 ... Catalytic converter, 40 ... Air-fuel ratio sensor, 46 ... Accelerator pedal 48 ... Accelerator opening sensor, 50 ... Internal combustion engine speed sensor, 52 ... Reference crank angle sensor, 54 ... Cooling water temperature sensor, 56 ... Intake air temperature sensor, 58 ... Outside air temperature sensor, 60 ... Exhaust temperature sensor, AC ... Air conditioner .

Claims (8)

An internal combustion engine control device for controlling an intake air amount during idle operation of an internal combustion engine,
Idle driving stability detecting means for detecting driving stability in idle driving;
Stability determination means for determining whether or not the operation stability detected by the idle operation stability detection means is within a stable range;
The difference between the actual intake air amount and the target intake air amount is calculated during the period when the operational stability is determined to be within the stable range by the stability determination means, and the stable intake correction amount is calculated according to the difference. A stable intake correction amount calculating means,
Metastability determination means for determining whether or not the operation stability detected by the idle operation stability detection means is within a metastable range set in a range wider than the stability range;
A difference between an actual intake air amount and a target intake air amount is obtained during a period when the driving stability is determined to be within the metastable range by the metastability determination means, and a metastable intake air according to the difference A metastable intake correction amount calculating means for calculating a correction amount while suppressing the correction amount in comparison with the stable intake correction amount;
Intake adjustment amount correction means for correcting the adjustment amount in the intake amount adjustment mechanism by the intake correction amount that has been calculated within the stable intake correction amount and the metastable intake correction amount;
An internal combustion engine control apparatus comprising: 2. The internal combustion engine control device according to claim 1, wherein the stable range and the metastable range are set as a fluctuation range of the internal combustion engine speed or the target intake air amount. 3. The air intake adjustment amount correction means according to claim 1, wherein the intake air adjustment amount correction means divides the intake air correction amount into a plurality of intervals when correcting the adjustment amount of the intake air amount adjustment mechanism by the intake air correction amount. An internal combustion engine controller that corrects an adjustment amount of the intake air amount adjustment mechanism step by step. 4. The internal combustion engine control device according to claim 1, wherein the metastable intake correction amount calculating unit increases the suppression of the metastable intake correction amount as the operating stability is lower. 5. 5. The internal combustion engine controller according to claim 1, wherein the internal combustion engine speed is controlled to a target speed by adjusting an ignition timing of the internal combustion engine. 6. The metastable intake correction amount calculation means according to claim 5, wherein the greater the absolute value of the difference between the actual internal combustion engine speed and the target speed, the weaker the suppression of the metastable intake correction amount. A control apparatus for an internal combustion engine. 7. The internal combustion engine control device according to claim 5, wherein the metastable intake correction amount calculation means weakens the suppression of the metastable intake correction amount as the ignition timing adjustment amount increases. 8. The method according to claim 1, wherein a combination of a plurality of the metastability determination means and the metastable intake correction amount calculation means having different metastable ranges is provided. Internal combustion engine control device.

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