JP6613612B2 - Engine control device - Google Patents

Description

  The present invention relates to a control device that controls the opening of a throttle valve provided in an engine.

  Conventionally, a technique for controlling the opening of a throttle valve using an upstream pressure and a downstream pressure of a throttle valve provided in an intake system of an engine is known. For example, a technique has been proposed in which the pressure ratio of the downstream pressure to the upstream pressure is calculated for the intake air passing through the throttle valve, and the throttle opening is controlled using the flow velocity estimated from the pressure ratio. In addition, a technique has been proposed in which a pressure difference between the upstream pressure and the downstream pressure of the throttle valve is calculated and the throttle opening is increased or decreased according to the pressure difference. With these controls, the amount of intake air introduced into the cylinder of the engine is estimated, and the throttle opening is controlled so as to obtain an appropriate engine output (see Patent Documents 1 and 2).

By the way, in the control of the throttle opening as described above, the correspondence relationship between the throttle opening and the opening area is grasped, and the opening area through which a desired intake air amount can pass is calculated. There is a method of setting the corresponding throttle opening. The correspondence relationship between the throttle opening and the opening area is acquired in advance by experiment or theoretical calculation, and is stored in the engine electronic control device in the form of a map or a mathematical expression, for example (see Patent Document 3).
On the other hand, this correspondence may change due to the influence of individual variations of throttle valves, deposit adhesion due to low pressure EGR gas, and the like. Therefore, in order to improve the controllability of the intake air amount, it is desired to appropriately correct and learn the correspondence between the throttle opening and the opening area.

Japanese Unexamined Patent Publication No. 2014-034908 JP 2006-152821 JP 2006-022696 JP

  When the controllability of the intake air amount is observed paying attention to the upstream pressure and the downstream pressure of the throttle valve, there is a control region in which the increase / decrease amount of the intake air amount with respect to the change in the throttle opening is remarkably reduced. This control region includes non-critical regions (regions where the ratio between upstream pressure and downstream pressure is close to 1 and the flow velocity has not reached the critical velocity), iso-pressure regions (regions where upstream pressure and downstream pressure are substantially equal), etc. Called. In this control area, the adjustment amount of the throttle opening required to increase / decrease the intake air amount becomes large, and the correction amount of the throttle opening tends to fluctuate greatly. It becomes difficult to correct and learn appropriately. On the other hand, if correction and learning in this control region are uniformly prohibited, the frequency of performing correction and learning decreases, and it becomes difficult to optimize the correspondence between the opening and the opening area.

  One of the purposes of the present invention was devised in view of the above problems, and an engine control device capable of appropriately correcting the correspondence between the opening degree of the throttle valve and the opening area. Is to provide. It should be noted that the present invention is not limited to this purpose, and is an operational effect that is derived from each configuration shown in “Mode for Carrying Out the Invention” to be described later. Can be positioned as a purpose.

(1) The engine control device disclosed herein controls the opening degree of the throttle valve based on the relationship between the opening degree and the opening area of the throttle valve and the target flow rate and actual flow rate of the intake air in the throttle valve. An engine control device. The control device includes a calculation unit that calculates a pressure ratio that is a ratio of the downstream pressure to the upstream pressure of the throttle valve, and a correction unit that corrects the opening based on the target flow rate and the actual flow rate. Wherein the correction unit, when the pressure ratio as compared with the case of less than the predetermined pressure ratio above the predetermined pressure ratio, Ru is aging the opening to reduce the correction amount per unit time of the opening .

Here, the ratio of the upstream pressure to the downstream pressure is defined as a second pressure ratio. The correction unit may correct the opening degree using the second pressure ratio instead of the pressure ratio. In this case, the correction unit decreases the correction amount per unit time of the opening degree when the second pressure ratio is less than the second predetermined pressure ratio as compared with the case where the second pressure ratio is equal to or higher than the second predetermined pressure ratio. It is preferable.
That is, when the upstream pressure and the downstream pressure are close to each other (when the pressure ratio and the second pressure ratio are close to 1), the correction unit performs the other cases (the pressure ratio and the second pressure). It is preferable to correct the opening at a slower speed than when the ratio is away from 1.

(2) It is preferable to include a second calculation unit that calculates a flow rate correlation value having a value corresponding to the difference between the target flow rate and the actual flow rate. In this case, it is preferable that the correction unit corrects the opening when the flow rate correlation value has a value that makes the difference amount equal to or larger than a predetermined amount.
The flow rate correlation value includes a difference (flow rate difference) between the target flow rate and the actual flow rate, and a ratio (flow rate ratio) between the target flow rate and the actual flow rate. That is, the correction unit performs the correction when the difference between the target flow rate and the actual flow rate is greater than or equal to a predetermined difference, or when the ratio of the actual flow rate to the target flow rate is outside a predetermined range including 1. It is preferable to implement.

(3) When the pressure ratio is less than the predetermined pressure ratio, learning is performed to reflect the correction amount in the correction unit in the relationship, and when the pressure ratio is greater than or equal to the predetermined pressure ratio, the learning is performed. It is preferable to provide a learning unit that stops.
For example, the learning is stopped when the pressure ratio (or the second pressure ratio) is close to 1, and the learning is performed when the pressure ratio (or the second pressure ratio) is away from 1. It is preferable.

(4) It is preferable that the learning is performed after the correction amount is stabilized. In other words, it is preferable that the learning unit performs the learning when the correction amount in the correction unit is stable. It is preferable to learn the correction contents when the correction amount becomes substantially constant.
(5) It is preferable that the learning is performed at a speed slower than the correction. That is, it is preferable that the learning unit performs the learning at a learning speed slower than a correction speed by the correction unit. It is preferable that the learning amount per unit time in the learning unit is smaller than the correction amount per unit time in the correction unit.

  According to the disclosed engine control device, the correspondence between the opening degree of the throttle valve and the opening area can be optimized by reducing the correction amount in the correction unit using the pressure ratio.

It is a block diagram which shows the structure of the control apparatus of an engine. (A) is a graph showing the relationship between the pressure ratio and the flow velocity equivalent value in the throttle valve, and (B) is a graph showing the relationship between the pressure ratio and the opening area for each engine speed. (A) is a graph showing the correspondence between the opening area of the throttle valve and the opening, and (B) is a graph showing the correspondence before and after learning. It is a flowchart which shows the control content implemented with the control apparatus of an engine. (A)-(F) are the graphs for demonstrating the correction | amendment and learning content in case a pressure ratio is less than predetermined pressure ratio. (A)-(F) are the graphs for demonstrating the content of correction | amendment when a pressure ratio is more than predetermined pressure ratio.

  An engine control apparatus as an embodiment will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the present embodiment can be implemented with various modifications without departing from the spirit thereof. Further, they can be selected as necessary, or can be appropriately combined.

[1. Constitution]
FIG. 1 is a diagram showing an engine 10 mounted on a vehicle and an engine control device 8 that controls the engine 10. A throttle valve 13 is interposed in the intake passage 11 of the engine 10, and an air flow sensor 14 for detecting the intake flow rate Q is provided upstream thereof. An intake manifold pressure sensor 15 that detects the intake manifold pressure P ₂ (the pressure of the intake manifold 12) is provided on the downstream side of the throttle valve 13. Numerals 16-18 in FIG. 1 is a accelerator opening sensor 16, an atmospheric pressure sensor 17 for detecting the atmospheric pressure P _1, an engine rotational speed sensor 18 for detecting the engine rotational speed Ne for detecting an accelerator opening degree Ac . Information detected by the sensors 14 to 18 is transmitted to the engine control device 8.

  The engine control device 8 is an electronic control device that is connected to an in-vehicle network and controls the operating state of the engine 10 and is an electronic device in which a processor device 6 such as a CPU and MPU and a memory device 7 such as a ROM and RAM are integrated. The engine control device 8 has a function of controlling at least the opening of the throttle valve 13 (throttle opening θ). Here, the throttle opening degree θ is controlled so that the intake amount corresponding to the torque and output required for the vehicle is introduced into the cylinder. A program for controlling the throttle opening θ is recorded in the memory device 7 and executed by the processor device 6. A block diagram for explaining the processing contents of throttle opening control is shown in the engine control device 8 of FIG.

  When the processing contents of the throttle opening control are functionally classified, the engine control device 8 is provided with a calculation unit 1, a control unit 2, a second calculation unit 3, a correction unit 4, and a learning unit 5. In the present embodiment, each of these functions is realized by software recorded in the memory device 7. However, some or all of the functions may be realized by hardware (electronic control circuit), or may be realized by using software and hardware together.

[1-1. Calculation unit]
The calculation unit 1 calculates a target throttle opening degree _θth , which is a control target value of the throttle opening degree θ, according to torque and output required for the vehicle. Here, a target intake air flow rate Q _th that is a target value of the intake air amount that is desired to pass through the throttle valve 13 is calculated, and a pressure correlation value that represents the relationship between the upstream pressure and the downstream pressure of the throttle valve 13 is calculated. A flow velocity equivalent value V corresponding to the flow velocity of the intake air passing through the throttle valve 13 is calculated based on the pressure correlation value. Further, based on the target intake flow rate Q _th and the flow velocity equivalent value V, a target opening area S _th that is a target value of the opening area S in the throttle valve 13 is calculated. Then, the target throttle opening degree θ _th is calculated based on the target opening area S _th . Calculated here information of the target throttle opening theta _th is transmitted to the control unit 2.

The target intake air flow rate Q _th corresponds to the intake air amount (mass flow rate) necessary to generate the output required for the engine 10 (request output). The magnitude of the required output of the engine 10 is calculated according to the external load device (transmission, air conditioner, various auxiliary machines, etc.), the accelerator opening Ac, and the engine rotational speed Ne. The specific calculation method of the target intake flow rate Q _th is arbitrary, and various known calculation methods can be employed.

The pressure correlation value is a parameter representing a relative relationship between the upstream pressure and the downstream pressure of the throttle valve 13, and is, for example, a “pressure ratio” that is a ratio of the downstream pressure to the upstream pressure or a ratio of the upstream pressure to the downstream pressure. This includes a “second pressure ratio”. In the present embodiment, the atmospheric pressure P ₁ is defined as an upstream pressure, the intake manifold pressure P ₂ is defined as a downstream pressure, and the ratio of the intake manifold pressure P _{2 to} the atmospheric pressure P ₁ is defined as a “pressure ratio R” (R = P ₂ / P ₁ ). The pressure ratio R is an example of a pressure correlation value.

The flow velocity equivalent value V is calculated based on the pressure ratio R. The calculation unit 1 is preset with mathematical formulas, maps, graphs, and the like representing the relationship between the flow velocity equivalent value V and the pressure ratio R. The relationship between the flow velocity equivalent value V and the pressure ratio R is illustrated in FIG. The flow velocity equivalent value V has a characteristic that it approaches 0 as the pressure ratio R approaches 1 and gradually approaches a predetermined velocity equivalent value V ₀ (a critical velocity corresponding to sound velocity) as the pressure ratio R approaches ₀ .

The target opening area S _th is calculated based on the target intake flow rate Q _th and the flow velocity equivalent value V. In general, the intake flow rate Q passing through the throttle valve 13 can be expressed by the product of the opening area S of the throttle valve 13, the flow velocity, and the intake density ρ. Therefore, the target opening area S _th corresponds to a value obtained by dividing the target intake flow rate Q _th by the product of the flow velocity and the intake density ρ. The intake air density ρ may be a constant, or may be estimated based on the intake air temperature (outside air temperature) or intake manifold temperature.

The target throttle opening degree _θth is calculated based on the target opening area _Sth . The calculation unit 1 is preset with mathematical formulas, maps, graphs, and the like representing the correspondence between the opening area S of the throttle valve 13 and the throttle opening θ. The relationship between the opening area S and the throttle opening θ is illustrated in FIG. The throttle opening θ has a characteristic that increases as the opening area S increases, but the increase rate of the throttle opening θ decreases as the opening area S increases (the slope decreases as the right side of the graph decreases). Have.

Based on such a correspondence, the calculation unit 1 calculates the throttle opening degree θ corresponding to the target opening area S _th as the target throttle opening degree θ _th . Here, the map that defines the correspondence between the opening area S and the throttle opening θ is referred to as an “opening / opening area map”. An arbitrary point on the graph is referred to as a “state point”, and its position is expressed using coordinates of the opening area S and the throttle opening θ.

[1-2. Control unit]
The control unit 2 outputs a control signal of a target opening voltage corresponding to the target throttle opening θ _th calculated by the calculation unit 1 to the throttle valve 13. The relationship between the target throttle opening _θth and the target opening voltage is preset in the control unit 2 as a mathematical formula, map, or graph according to the characteristics of the throttle valve 13. If the actual throttle opening θ is controlled so as to coincide with the target throttle opening θ _th , the intake flow rate Q passing through the throttle valve 13 theoretically matches the target intake flow rate Q _th . On the other hand, due to individual variations of the throttle valve 13 and the like, the intake flow rate Q and the target intake flow rate Q _th may not match, and the deviation of the intake flow rate Q from the target intake flow rate Q _th may remain. Such a deviation is calculated by the second calculation unit 3.

[1-3. Second calculation unit]
The second calculation unit 3 calculates a flow rate correlation value having a value corresponding to the difference between the target flow rate of the intake air passing through the throttle valve 13 and the actual flow rate. The flow rate correlation value is a parameter indicating how much the target flow rate and the actual flow rate are deviated. For example, the difference between the target flow rate and the actual flow rate (flow rate difference) or the ratio between the target flow rate and the actual flow rate (flow rate ratio). ) Is included in this. In the present embodiment, the target intake flow rate Q _th is set as the target flow rate, the intake flow rate Q detected by the air flow sensor 14 is set as the actual flow rate, and a value obtained by subtracting the intake flow rate Q from the target intake flow rate Q _{th is referred} to as “flow rate difference D”. Define (D = Q _th -Q). The flow rate difference D is an example of a flow rate correlation value. Information on the flow rate difference D calculated here is transmitted to the correction unit 4.

[1-4. Correction part]
The correction unit 4 corrects the throttle opening θ based on the target flow rate and actual flow rate of the intake air passing through the throttle valve 13. Here, for example, the throttle opening θ is corrected based on the flow rate correlation value. In the present embodiment, the throttle opening θ is corrected when the absolute value of the flow rate difference D is equal to or greater than a predetermined value D _th (a predetermined amount or more). At this time, when the flow rate difference D is positive (when the intake flow rate Q is smaller than the target intake flow rate Q _th by a predetermined value D _th or more), the throttle opening θ is corrected to be increased, and when the flow rate difference D is negative ( When the intake air flow rate Q is larger than the target intake flow rate Q _th by a predetermined value D _th or more), the throttle opening θ is corrected to decrease.

The correction amount may be set according to the flow rate difference D, or may be a fixed value set in advance. In the present embodiment, a correction amount having a magnitude obtained by multiplying the flow rate difference D by the gain g is set. With such correction, the correction amount increases as the absolute value of the flow rate difference D increases, and the correction amount decreases as the absolute value of the flow rate difference D decreases. Thereby, the throttle opening θ is corrected so that the flow rate difference D gradually approaches zero. Further, the correction unit 4 calculates the change in the throttle opening θ after correction as the total correction amount X with reference to the pre-correction. This total correction amount X corresponds to the total correction amount after the correction is started. For example, when the target intake flow rate _Qth is constant and the flow rate difference D becomes substantially zero by correction, the correction amount does not increase or decrease any further, and the value of the total correction amount X is also substantially constant.

On the other hand, in an operating state where the upstream pressure and the downstream pressure of the throttle valve 13 are relatively close, the correction amount of the throttle opening θ is likely to change suddenly, and the correction accuracy may be reduced. For example, the flow rate difference D may oscillate around zero and the total correction amount X may also oscillate accordingly. In view of such a problem, the correction unit 4 changes the correction method based on the pressure ratio R. That is, as compared with the case where the pressure ratio R is less than the predetermined pressure ratio _Rth , when the pressure ratio R is equal to or greater than the predetermined pressure ratio _Rth , the correction amount per unit time is decreased and the correction speed is decreased. To do. For example, than the gain g ₁ when the pressure ratio R is less than the predetermined pressure ratio R _th, the pressure ratio R is set to be smaller the gain g ₂ when the predetermined pressure ratio R _th or (g ₂ <g ₁₎ . As a result, the correction amount of the throttle opening θ is less likely to change suddenly, and control stability is improved. The specific value of the predetermined pressure ratio R _th (predetermined amount) can be arbitrarily set. In the present embodiment, the predetermined pressure ratio R _th is set to a value close to 1 (for example, 0.95).

As described above, when the flow rate correlation value has a value that makes the difference amount equal to or larger than the predetermined amount (when the absolute value of the flow rate difference D is equal to or larger than the predetermined value _Dth ), the correction unit 4 sets the throttle opening θ. Has a function to correct. The correction unit 4, as compared to the pressure ratio R is less than the predetermined pressure ratio R _th, when the pressure ratio R is a predetermined pressure ratio R _th or more, reduces the correction amount per unit time functions have.

[1-5. Learning Department]
The learning unit 5 performs learning to reflect the correction amount set by the correction unit 4 in the opening / opening area map as shown in FIG. Here, after the correction of the throttle opening θ by the correction unit 4 is performed, learning of the throttle opening θ is performed on the condition that the correction amount is stable. In this embodiment, the flow rate will be the difference D is approximately zero, the state is a state continues for a predetermined time or longer, if the total correction amount X is a predetermined correction amount X _th or more, the learning is performed.

For example, as shown in FIG. 3B, when the target opening area S _th of the throttle valve 13 is S ₀ , the target throttle opening θ _th calculated based on the opening / opening area map is θ _0. Suppose that If the flow rate difference D between the target intake flow rate Q _th and the intake flow rate Q at the state point (S ₀ , θ ₀ ) is equal to or greater than a predetermined value D _th , the correction unit 4 corrects the throttle opening θ. After the state point moves from (S ₀ , θ ₀ ) to (S ₀ , θ ₁ ) by this correction, when the correction amount is stable (stable with the position of the state point stopped), the learning unit 5 now Conduct learning.

The learning speed is set to be slower than the correction speed by the correction unit 4. That is, instead of changing to immediately theta ₁ the throttle opening theta ₀ corresponding to the opening area S _0, the state point (S _{0, θ 0)} from (S _{0, θ 1)} is moved to the slow While updating. For example, the gain g ₃ having a value smaller than the gain g ₂ is multiplied by the flow rate difference D (g ₃ <g ₂ ), and the value is used as the learning amount of the throttle opening θ ₀ . Further, the graph shape after learning is deformed so as to approach the moved state point. By repeatedly performing learning of such state points, the correspondence relationship between the opening area S and the throttle opening θ is changed from a broken line graph to a solid line graph as shown in FIG. Thirteen individual variations are absorbed.

On the other hand, in an operating state where the upstream pressure and the downstream pressure of the throttle valve 13 are relatively close, not only the correction accuracy but also the learning accuracy can be reduced. In view of such a problem, the learning unit 5 changes the learning method based on the pressure ratio R. That is, as in conditions of learning that the pressure ratio R is less than the predetermined pressure ratio R _th, when the pressure ratio R is a predetermined pressure ratio R _th or more stops learning. Here, the predetermined pressure ratio R _th is the same value as the predetermined pressure ratio R _th at which the correction method in the correction unit 4 is changed. Thereby, learning in an unstable state in which the correction amount of the throttle opening θ is likely to change suddenly is avoided, and a decrease in learning accuracy is suppressed.

A relationship between the pressure ratio R and the opening area S of the throttle valve 13 is shown in FIG. The operation region in which learning can be performed is a region where the pressure ratio R is less than the predetermined pressure ratio _Rth . Therefore, when the engine rotational speed Ne is Ne ₁ , the throttle opening degree θ corresponding to the opening area S cannot be learned unless the opening area S is between 0 and S ₁ . On the other hand, as the engine speed Ne increases, the opening area S that gives the same pressure ratio R increases. As a result, when the engine speed Ne is Ne ₂ (Ne ₁ <Ne ₂ ), the learning region is expanded between the opening area S from 0 to S ₂ (S ₁ <S ₂ ). Further, when the engine speed Ne increases and becomes Ne ₃ (Ne ₂ <Ne ₃ ), the learning area further expands, and if the opening area S is between 0 and S ₃ (S ₂ <S ₃ ), learning is performed. Is possible.

Thus, even in the case where the learning condition is that the pressure ratio R is less than the predetermined pressure ratio _Rth , the throttle corresponding to a wide range of the opening area S in the operation region where the engine rotational speed Ne is relatively high. The opening degree θ can be learned.
Further, as described above, the learning unit 5 corresponds the correction amount in the correction unit 4 when the pressure correlation value has a value close to 1 (when the pressure ratio R is less than the predetermined pressure ratio _Rth ). _Has a function of stopping learning when the pressure correlation value has a value far from 1 (when the pressure ratio R is equal to or greater than the predetermined pressure ratio _Rth ).

[2. flowchart]
The procedure of throttle opening control is illustrated in FIG. The control shown in this flowchart is repeatedly executed by the engine control device 8 at a predetermined cycle. The calculation unit 1 calculates the target intake flow rate Q _th based on the required output of the vehicle (step A1), and calculates the ratio of the intake manifold pressure P _{2 to} the atmospheric pressure P ₁ as the pressure ratio R (step A2). Further, the flow velocity equivalent value V is calculated from the pressure ratio R, and the target opening area S _th is calculated based on the flow velocity equivalent value V and the target intake flow rate Q _th (step A3). Thereafter, a target throttle opening degree θ _th corresponding to the target opening area S _th is calculated based on the opening degree / opening area map (step A4), and a control signal of the target opening voltage corresponding thereto is sent from the control unit 2. Output to the throttle valve 13 (step A5).

On the other hand, the second calculation unit 3 calculates a flow rate difference D between the target intake flow rate Q _th and the intake flow rate Q (step A6), and determines whether or not the absolute value of the flow rate difference D is equal to or greater than a predetermined value D _th. (Step A7). Here, | D | in the case of ≧ D _th is set is corrected gradient corresponding to the pressure ratio R (correction speed), the correction of the throttle opening θ is performed (step A8～A10). That is, the pressure ratio R is gain g ₁ is used is less than the predetermined pressure ratio R _th, the correction is carried out at a relatively large correction gradient (fast correction speed) (step A9). On the other hand, the pressure ratio R is small gain g ₂ is used than the gain g ₁ if a predetermined pressure ratio R _th or more, the correction is carried out at a relatively small correction gradient (slow correction rate) (step A10). After these corrections are performed, the process proceeds to step A11. In step A7 | also proceeds to step A11 if the <D _th | D.

In step A11, the correction unit 4 calculates the total correction amount X. Here, when the absolute value of the total correction amount X is a predetermined correction amount X _th or more (step A12), the pressure ratio R is smaller gain g ₃ than the gain g ₂ is less than the predetermined pressure ratio R _th reference Thus, learning is performed more slowly than the correction speed (steps A13 and A14). Thereby, the correction content in the correction unit 4 is gradually reflected in the opening / opening area map, and the correspondence between the throttle opening θ and the opening area S is stably optimized. On the other hand, if the pressure ratio R is greater than or equal to the predetermined pressure ratio _Rth , learning is prohibited (step A15). Note that if | X | <X _th , learning is not performed and the present flow ends.

[3. Action]
5A to 5F respectively show the intake flow rate Q, the pressure ratio R, the target opening area S _th , the throttle opening θ, and the total correction amount X when the pressure ratio R is less than the predetermined pressure ratio R _th. , It is a graph which shows a time-dependent change of a learning value. When the accelerator pedal is depressed between time t ₁ ~t _3, the accelerator opening Ac, is the target intake air flow rate Q _th is calculated based such as the engine rotation speed Ne, the flow velocity equivalent value V is calculated according to the pressure ratio R Is done. Further, the target opening area Sth is calculated from the target intake flow rate Q _th and the flow velocity equivalent value V, and the target throttle opening θ _th corresponding to this is calculated. Then, the actual throttle opening θ is changed to the target throttle opening θ. _The throttle valve 13 is controlled so as to coincide with _th .

When the flow rate difference D between the actual intake air flow rate Q at time t ₂ the target intake air flow rate Q _th is equal to or greater than a predetermined value D _th, the correction of the throttle opening θ is started. At this time, since the pressure ratio R is less than the predetermined pressure ratio R _th , correction is performed with a relatively large correction gradient as shown in FIG. Then, when at time t ₄ becomes the flow rate difference D is approximately zero, the total correction amount X substantially constant value, the correction amount is stabilized. The height of the hatched area in FIG. 5D corresponds to the total correction amount X. The total correction amount X and the learning condition converges to a substantially constant value by a predetermined correction amount X _th or more is satisfied, the learning of the throttle opening θ is started (time t _5). In this learning, as shown in FIG. 3B, the position of the state point (the coordinate of the throttle opening θ) is corrected, and the graph shape is changed and updated to correspond to the corrected state point. . As a result, as indicated by a one-dot chain line in FIG. 5D, the correction amount of the throttle opening θ is absorbed as a learning value. When all of the total correction amount X at time t ₆ is reflected in the opening-opening area map, the learning is completed.

_{6A to 6F} respectively show the intake flow rate Q, the pressure ratio R, the target opening area S _th , the throttle opening θ, and the total correction amount X when the pressure ratio R is equal to or greater than the predetermined pressure ratio R _th. , It is a graph which shows a time-dependent change of a learning value. Accelerator pedal is depressed at time t _7, when the flow rate difference D is equal to or greater than a predetermined value D _th at time t _8, the correction of the throttle opening θ is started. At this time, if the pressure ratio R is equal to or greater than the predetermined pressure ratio R _th , correction is performed with a relatively small correction gradient as shown in FIG. The broken line in FIG. 6 (E) is a correction gradient when the pressure ratio R is less than the predetermined pressure ratio _Rth . As a result, a sudden change in the correction amount of the throttle opening θ is suppressed. If the pressure ratio R is equal to or greater than the predetermined pressure ratio _Rth , learning stops as shown in FIG. Thereby, learning in an unstable state is avoided.

[4. effect]
(1) In the above-described engine control unit 8, when the pressure ratio R is a predetermined pressure ratio R _th or more, as compared to the pressure ratio R is less than the predetermined pressure ratio R _th, per unit time throttle The correction amount of the opening degree θ decreases, and the correction speed decreases. As a result, it is possible to suppress sudden changes in the correction amount and vibrations (the correction amount greatly fluctuates and fluctuates) in the correction unit 4. Further, even in an operating state where the upstream pressure and the downstream pressure of the throttle valve 13 are relatively close, the actual intake flow rate Q can be converged to the target intake flow rate Q _th , and the opening degree θ of the throttle valve 13 Correspondence with the opening area S can be optimized, and the controllability of the engine 10 can be improved.

(2) In the engine control device 8 described above, correction is performed using the flow rate difference D between the actual intake flow rate Q and the target intake flow rate Q _th in the throttle valve 13, so that the intake flow rate Q is changed to the target intake flow rate Q _th. The controllability of the engine 10 can be improved.
(3) In the engine control device 8 described above, by providing the learning unit 5, the correction content in the correction unit 4 can be reflected in normal control. Therefore, the convergence of the intake flow rate Q with respect to the target intake flow rate Q _th can be improved, and the controllability of the engine 10 can be improved. Further, since the content learned by the learning unit 5 is excluded from the correction content in the subsequent normal control, the intake flow rate Q is accurately set to the target intake flow rate Q _th while reducing the calculation load in the correction unit 4. Can be matched.

(4) In the engine control device 8 described above, when the correction amount is stable, the correction content is learned, so that the learning accuracy can be improved and the controllability of the engine 10 can be improved.
(5) In the engine control device 8 described above, by making the learning speed slower than the correction speed, a more reliable correction amount can be learned, the learning accuracy can be improved, and the controllability of the engine 10 can be improved. Can be improved.
(6) In the engine control device 8 described above, by using the ratio of the downstream pressure to the upstream pressure of the throttle valve 13 (pressure ratio R), the flow velocity of the intake air passing through the throttle valve 13 can be accurately grasped. The controllability of the engine 10 can be improved.

[5. Modified example]
In the above-described embodiment, the pressure ratio R in which the atmospheric pressure P ₁ is the upstream pressure and the intake manifold pressure P ₂ is the downstream pressure is used, but the specific types of the upstream pressure and the downstream pressure are not limited to this. For example, pressure sensors may be provided immediately upstream and downstream of the throttle valve 13, and the pressure ratio R may be calculated using values detected by these sensors. Further, not only the ratio of the downstream pressure to the upstream pressure but also the ratio of the upstream pressure to the downstream pressure can be used. It is also possible to use a difference in downstream pressure with respect to upstream pressure or a difference in upstream pressure with respect to downstream pressure. Further, although an example of correcting and learning the throttle opening θ based on the flow rate difference D between the intake flow rate Q and the target intake flow rate Q _th is illustrated, instead of this flow rate difference D, the target intake flow rate Q _th It is also possible to use the ratio of the intake flow rate Q or the ratio of the target intake flow rate Q _{th to} the intake flow rate Q. In any case, the same effects as those of the above-described embodiment can be obtained.

DESCRIPTION OF SYMBOLS 1 Calculation part 2 Control part 3 2nd calculation part 4 Correction | amendment part 5 Learning part 6 Processor apparatus 7 Memory apparatus 8 Engine control apparatus 10 Engine 13 Throttle valve

Claims (5)

In the engine control apparatus for controlling the opening degree of the throttle valve based on the relationship between the opening degree and the opening area of the throttle valve, and the target flow rate and actual flow rate of the intake air in the throttle valve,
A calculation unit that calculates a pressure ratio that is a ratio of the downstream pressure to the upstream pressure of the throttle valve;
A correction unit that corrects the opening based on the target flow rate and the actual flow rate,
Wherein the correction unit, when the pressure ratio as compared with the case of less than the predetermined pressure ratio above the predetermined pressure ratio, Ru is aging the opening to reduce the correction amount per unit time of the opening An engine control device. A second calculation unit for calculating a flow rate correlation value having a value corresponding to the difference between the target flow rate and the actual flow rate,
2. The engine control device according to claim 1, wherein the correction unit corrects the opening degree when the flow rate correlation value has a value that makes the difference amount equal to or larger than a predetermined amount. Learning to reflect the correction amount in the correction unit in the relationship when the pressure ratio is less than the predetermined pressure ratio, and to stop the learning when the pressure ratio is equal to or higher than the predetermined pressure ratio The engine control device according to claim 1, further comprising a unit. The engine control device according to claim 3, wherein the learning is performed after the correction amount is stabilized. The engine control device according to claim 3 or 4, wherein the learning is performed at a speed slower than the correction.

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