JP2004257317A - Intake air amount control device for internal combustion engine - Google Patents

Abstract

To provide an intake air amount control device capable of accurately obtaining a relationship between a throttle opening degree and an intake air amount in a predetermined throttle opening degree region.
An intake air amount control device according to the present invention includes a throttle valve provided on an engine intake passage, and a detecting means for detecting a relationship between a throttle opening degree and an intake air amount in a specific state. . The relationship between the throttle opening and the intake air amount in at least two specific states is detected by the detecting means. Based on these detected relationships, the relationship between the throttle opening and the intake air amount in a predetermined throttle opening region is determined. Desired. Then, the target intake air amount is calculated in accordance with the engine operating state, and the throttle opening is controlled in accordance with the relationship obtained as described above so as to achieve the target intake air amount.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an intake air amount control device.
[0002]
[Prior art]
Generally, in a vehicle-mounted internal combustion engine such as an automobile engine, in order to maintain the engine operating state optimally, a target value (hereinafter, referred to as "the amount of air" drawn into the combustion chamber via the intake pipe based on the engine operating state is referred to as " The target intake air amount is calculated, and the opening of a valve (hereinafter, referred to as a "throttle valve") for adjusting the intake air amount to achieve the target intake air amount (hereinafter, "throttle opening degree") is calculated. "). In this case, due to responsiveness and the like, the throttle opening is not determined so that the intake air amount becomes the target intake air amount based on the intake air amount detected by an air flow meter or the like, but is obtained in advance and electronically. The throttle opening is adjusted so that the intake air amount becomes the target intake air amount based on the relationship between the throttle opening degree and the intake air amount in the entire throttle opening degree stored in the control unit or the like.
[0003]
However, the actual relationship between the throttle opening and the amount of intake air in the entire throttle opening is not always constant, and changes due to, for example, foreign matter adhering and accumulating on the intake pipe or the like. Therefore, the relationship between the throttle opening and the intake air amount in the entire throttle opening stored in the electronic control unit needs to be updated as needed in accordance with the use of the internal combustion engine. Such an intake air amount control device that constantly updates the relationship between the throttle opening degree and the intake air amount over the entire throttle opening degree stored in the electronic control unit includes, for example, an internal combustion engine after warm-up is completed. The throttle opening during idle operation (hereinafter referred to as "engine idle operation") (hereinafter referred to as "idle opening") and the intake air amount during engine idle operation (hereinafter referred to as "idle intake air amount") (Patents), and obtains the relationship between the throttle opening and the intake air amount in the entire throttle opening range based on the detected relationship between the idle opening and the idle intake air amount. Reference 1).
[0004]
[Patent Document 1]
JP 2000-257490 A
[Patent Document 2]
JP-A-9-268935
[0005]
[Problems to be solved by the invention]
However, adhesion and deposition of foreign matter on the intake pipe and the like are performed in various forms. Therefore, even if the relationship between the idle opening and the idle intake air amount is the same, the throttle opening over the entire throttle opening is Since the relationship with the intake air amount is often different, the relationship between the throttle opening and the intake air amount over the entire throttle opening cannot be accurately obtained only from the relationship between the idle opening and the idle intake air amount. . In particular, in the throttle opening range slightly larger than the idle opening, the amount of intake air for a specific throttle opening greatly changes depending on the form of attachment and accumulation of foreign matter around the throttle valve. It is particularly difficult to determine the relationship between the opening and the intake air amount based on the relationship between the idle opening and the idle intake air amount.
[0006]
In view of the above problem, an object of the present invention is to provide an intake air amount control device that can accurately determine a relationship between a throttle opening and an intake air amount in a predetermined throttle opening region.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the first invention comprises a throttle valve provided on an engine intake passage, and a detecting means for detecting a relationship between a throttle opening degree and an intake air amount in a specific state, The detecting means detects the relationship between the throttle opening and the intake air amount in at least two specific states, and based on these detected relationships, the relationship between the throttle opening and the intake air amount in a predetermined throttle opening region. And the throttle opening is controlled in accordance with the obtained relationship so that the target intake air amount is in accordance with the engine operating state.
Conventionally, throttle opening and suction in a predetermined throttle opening region are based on only the relationship between the throttle opening (particularly idle opening) and the amount of intake air (particularly idle intake air) in one specific state. According to the first invention, the relationship between the throttle opening and the intake air amount is determined based on the relationship between the throttle opening and the intake air amount in at least two specific states. Since the relationship between the throttle opening and the intake air amount is determined, the relationship between the throttle opening and the intake air amount can be determined more accurately. In this specification, the “relationship between the throttle opening and the intake air amount in a specific state” refers to the relationship between the throttle opening and the intake air amount at a certain throttle opening, or a certain intake air amount. Means the relationship between the throttle opening and the intake air amount, and "the relationship between the throttle opening and the intake air amount in the predetermined throttle opening region" means that the throttle opening is changed within the predetermined throttle opening region. Means the transition of the relationship between the throttle opening and the intake air amount.
[0008]
In a second aspect based on the first aspect, the predetermined throttle opening range is the entire throttle opening range.
In a third aspect based on the first or second aspect, at least one of the relationship between the throttle opening and the intake air amount in the specific state is such that the throttle opening is equal to or less than a predetermined throttle opening and the engine is warmed up. When the throttle opening is larger than the throttle opening during the subsequent engine idle operation (after warm-up is completed), or when the intake air amount is equal to or less than the predetermined intake air amount and larger than the intake air amount during the engine idle operation after warm-up. Is detected.
As described above, in the throttle opening region slightly larger than the idle opening amount, that is, in the intake air amount region slightly larger than the idle intake air amount, the specific state is determined by the form of attachment and accumulation of foreign matter around the throttle valve. The relationship between the throttle opening and the amount of intake air changes greatly. Therefore, it is most necessary to detect the relationship between the throttle opening and the intake air amount in a specific state. The throttle opening region is slightly larger than the idle opening amount (that is, the intake air amount region is slightly larger than the idle intake air amount). If the relationship between the throttle opening and the intake air amount in a specific state in the throttle opening region (or the intake air amount region) is detected, the throttle opening and the intake air amount in a predetermined throttle opening region are obtained. The relationship with can be determined accurately. Here, according to the third aspect, the relationship between at least one specific throttle opening that is larger than the idle opening and equal to or less than the predetermined throttle opening and the intake air amount, or more than the idle intake air amount and Since the relationship between at least one specific intake air amount equal to or less than the predetermined intake air amount and the throttle opening is detected, in particular, the relationship between the throttle opening and the intake air amount slightly larger than the idle opening amount, or Since the relationship between the intake air amount slightly larger than the idle intake air amount and the throttle opening is detected, the throttle opening region is slightly larger than the idle opening amount, or the intake air is slightly larger than the idle intake air amount. The relationship between the throttle opening and the intake air amount in the amount region can be more accurately obtained. The throttle opening region slightly larger than the idle opening is, for example, a throttle opening region required when the internal combustion engine is idling during warm-up, and is slightly smaller than the idle intake air amount. The large intake air amount region is, for example, an intake air amount region required when the internal combustion engine is idling during warm-up. In the following, only the throttle opening region slightly larger than the idle opening will be described, but the same applies to the intake air amount region slightly larger than the idle intake air amount.
[0009]
In a fourth aspect based on the third aspect, one of the relationship between the throttle opening and the intake air amount in the specific state is detected during engine idle operation after warm-up.
Generally, from the relationship between the idle opening and the idle intake air amount, it is necessary to accurately determine the relationship between the throttle opening and the intake air amount in a throttle opening region other than the throttle opening region slightly larger than the idle opening. it can. Further, as described above, from the relationship between the specific throttle opening slightly larger than the idle opening and the intake air amount, the throttle opening and the intake air amount in the throttle opening region slightly larger than the idle opening are determined. Can be determined accurately. According to the fourth aspect, the detection of the relationship between the idle opening and the idle intake air amount and the detection of the relationship between the throttle opening and the intake air amount at a throttle opening slightly larger than the idle opening are performed. Therefore, the relationship between the throttle opening and the intake air amount can be accurately obtained over the entire throttle opening.
[0010]
In a fifth aspect based on the third or fourth aspect, the throttle opening is controlled such that the engine speed becomes a predetermined speed during the engine idle operation after the warm-up.
According to the fifth aspect of the invention, at the time of the engine idle operation after the engine, control of the throttle opening such that the engine speed becomes a predetermined speed, that is, idle speed control control (hereinafter, referred to as “ISC control”) is performed. . Since the engine speed is maintained at the predetermined speed during the ISC control, the intake air amount is also maintained substantially constant. Therefore, by detecting the throttle opening during the ISC control, the relationship between the idle opening and the idle intake air amount can be detected.
[0011]
In a sixth aspect based on any one of the first to fifth aspects, the detection of the relationship between the throttle opening and the intake air amount in the specific state is performed during fuel cut control.
When detecting the relationship between the throttle opening and the intake air amount at a specific throttle opening, the throttle opening must be adjusted to the specific throttle opening for detection. If such adjustment is performed during normal operation of the internal combustion engine, the engine speed rapidly increases or decreases due to a change in the throttle opening, and the engine operating state becomes unintended by the user. Would. However, even when the engine is operating, if the fuel is not injected into the air taken into the internal combustion engine, the change in the throttle opening has little effect on the engine operating state. According to the sixth aspect, since the detection is performed during the fuel cut control, the influence of the detection on the engine operating state can be minimized.
Note that the fuel cut control means a control in which fuel is not injected from the fuel injection valve over the entire stroke of the internal combustion engine, or a control in which fuel that contributes to driving of the internal combustion engine is not injected from the fuel injection valve.
[0012]
In a seventh aspect based on any one of the first to fifth aspects, a catalyst for purifying exhaust gas of the internal combustion engine is further provided, and a relationship between the throttle opening degree and the intake air amount in the specific state is provided. The detection of the relationship is performed during the catalyst deterioration suppression control in which the fuel cut control is not performed even during deceleration of the vehicle equipped with the internal combustion engine in order to suppress the deterioration of the catalyst.
According to the seventh aspect, similarly to the sixth aspect, the detection is performed during the catalyst deterioration suppression control, so that the influence of the detection on the engine operating state can be minimized. Note that the catalyst deterioration suppression control generally means that while the vehicle equipped with the internal combustion engine is decelerating, fuel cut control is performed to stop the fuel injection, but even during such deceleration, the fuel cut control is performed. This is a control in which the throttle valve is set to an opening slightly larger than the idling opening and the fuel is slightly injected without performing the operation. This catalyst deterioration suppression control is performed, for example, when the catalyst bed temperature is extremely high, and prevents the exhaust gas having a high lean degree from flowing into the catalyst to promote the deterioration of the catalyst.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 shows an in-cylinder injection spark ignition type internal combustion engine. However, the present invention may be applied to another spark ignition type internal combustion engine or a compression ignition type internal combustion engine.
[0014]
As shown in FIG. 1, in a first embodiment of the present invention, an engine body 1 includes a cylinder block 2, a piston 3 reciprocating in the cylinder block 2, and a cylinder head 4 fixed on the cylinder block 2. Is provided. A combustion chamber 5 is formed between the piston 3 and the cylinder head 4. In the cylinder head 4, an intake valve 6, an intake port 7, an exhaust valve 8, and an exhaust port 9 are arranged for each cylinder. Further, as shown in FIG. 1, a spark plug 10 is arranged at the center of the inner wall surface of the cylinder head 4, and a fuel injection valve 11 is arranged around the inner wall surface of the cylinder head 4. A cavity 12 is formed on the top surface of the piston 3 from below the fuel injection valve 11 to below the spark plug 10.
[0015]
The intake port 7 of each cylinder is connected to a surge tank 14 via a corresponding intake branch 13, and the surge tank 14 is connected to an air cleaner (not shown) via an intake duct 15 and an air flow meter 16. The intake port 7, the intake branch pipe 13, the surge tank 14, the intake duct 15, and the like are collectively referred to as intake pipes that form an intake passage for sucking air into the combustion chamber. A throttle valve 18 driven by a step motor 17 is arranged in the intake duct 15, and a throttle position sensor 19 is attached to the throttle valve 18. An intake pressure sensor 20 is attached to the surge tank 14. On the other hand, the exhaust port 9 of each cylinder is connected to an exhaust manifold 21, and the exhaust manifold 21 is connected to a casing 23 containing an exhaust purification catalyst 22. The exhaust manifold 21 and the surge tank 14 are connected to each other via a recirculated exhaust gas (hereinafter, referred to as EGR gas) conduit 24, and an EGR gas control valve 25 is disposed in the EGR gas conduit 24.
[0016]
An electronic control unit (ECU) 31 is composed of a digital computer, and is connected to a ROM (Read Only Memory) 33, a RAM (Random Access Memory) 34, a CPU (Microprocessor) 35, A port 36 and an output port 37 are provided. The air flow meter 16 generates an output voltage proportional to the amount of intake air, and the throttle position sensor generates an output voltage proportional to the opening of the throttle valve (hereinafter referred to as "throttle opening"). Is input to the input port 36 via the corresponding AD converter 38. Further, the intake pressure sensor 20 generates an output voltage proportional to the pressure in the surge tank 14, and this output voltage is input to the input port 36 via the corresponding AD converter 38.
[0017]
A load sensor 41 that generates an output voltage proportional to the amount of depression of the accelerator pedal 40 is connected to the accelerator pedal 40, and the output voltage of the load sensor 41 is input to the input port 36 via the corresponding AD converter 38. You. The crank angle sensor 42 generates an output pulse every time the crankshaft rotates 30 degrees, for example, and this output pulse is input to the input port 36. The vehicle speed sensor 43 generates an output voltage corresponding to the speed of the vehicle equipped with the internal combustion engine, and this output voltage is also input to the input port 36 via the AD converter 38. The CPU 35 calculates the engine speed from the output pulse of the crank angle sensor 42. On the other hand, the output port 37 is connected to the ignition plug 10, the fuel injection valve 11, the step motor 17, and the EGR gas control valve 25 via the corresponding drive circuit 39.
[0018]
By the way, in general, in a vehicle-mounted internal combustion engine such as an automobile engine, a target value of an amount of air to be sucked into the combustion chamber 5 through an intake pipe (hereinafter, referred to as “target suction”) in order to maintain the engine operating state optimally. An air amount) is calculated based on the engine operating state, and the opening of a throttle valve (valve for adjusting the amount of intake air) 18 (hereinafter, “throttle opening”) is adjusted to the target intake air amount. ). In this case, if the throttle opening is adjusted so as to reach the target intake air amount based on the intake air amount detected by the air flow meter 16 or the like by the feedback control, the intake air is reduced due to the responsiveness of the air flow meter 16 and the throttle valve 18. It is difficult to quickly adjust the amount to the target air amount, and, for example, during a cold start of the internal combustion engine, the intake air amount and the like fluctuate irrespective of the throttle opening degree. The throttle opening is not stable when the throttle opening is adjusted at the same time. Therefore, conventionally, the relationship between the throttle opening degree and the intake air amount in the entire throttle opening degree is calculated in advance and stored in the ROM of the ECU, and the throttle opening degree in the entire throttle opening degree stored in the ROM during engine operation. The throttle valve is controlled to a throttle opening such that the intake air amount becomes the target intake air amount based on the relationship between the intake air amount and the intake air amount.
[0019]
However, the actual relationship between the throttle opening and the amount of intake air in the entire throttle opening is not always constant. For example, devices such as an intake pipe and a throttle valve disposed in the intake pipe (hereinafter referred to as “intake pipe and the like”). ) Changes due to the attachment and deposition of foreign matter. Therefore, it is necessary to update the relationship between the throttle opening and the intake air amount in the entire throttle opening stored in the ROM of the ECU in accordance with the attachment and accumulation of foreign matter on the intake pipe and the like. Therefore, conventionally, the throttle opening is adjusted to a specific intake air amount and the throttle opening at this time is detected, whereby the relationship between the specific intake air amount and the throttle opening is detected and detected. From this relationship, the relationship between the throttle opening and the intake air amount in the entire throttle opening is obtained.
[0020]
More specifically, in the related art (for example, Japanese Patent Application Laid-Open No. 2000-257490), when the internal combustion engine is idling after completion of warm-up (hereinafter referred to as “engine idling operation”), the engine speed is constant. The idle speed control control (hereinafter, referred to as "ISC control") for adjusting the throttle opening degree is performed so that When the ISC control is being performed, the engine speed is always maintained at a constant speed (hereinafter, referred to as “idle speed”), so that the intake air amount is basically substantially constant. (Hereinafter referred to as “idle intake air amount”). Therefore, when the throttle opening (hereinafter, referred to as “idle opening”) during the engine idling operation after the completion of warm-up is detected, the relationship between the idle opening and the idle intake air amount is detected. Then, the relationship between the throttle opening and the intake air amount over the entire throttle opening is determined based on the relationship between the idle opening and the intake air amount detected in this manner, and the ROM of the ECU is determined based on the determined relationship. Be updated. FIG. 2 shows the relationship between the throttle opening and the intake air amount in the entire throttle opening obtained in this manner. In FIG. 2, the horizontal axis indicates the throttle opening, and the vertical axis indicates the intake air amount.
[0021]
In FIG. 2, the one-dot chain line α indicates the entire throttle opening degree when there is almost no adhesion or accumulation of foreign matter on the intake pipe or the like (that is, when the internal combustion engine is used in a new state; hereinafter, referred to as “initial state”). Shows the relationship between the throttle opening and the amount of intake air in FIG. On the other hand, the broken line β in FIG. 2 shows the relationship between the throttle opening and the intake air amount in the entire throttle opening obtained as described above. The dashed line β basically represents a predetermined amount θ obtained by subtracting the throttle opening x corresponding to the idle intake air amount gai in the initial state from the idle opening y corresponding to the idle intake air amount gai detected as described above. However, the dash-dot line α is shifted in the direction in which the throttle opening increases. However, in general, the influence of the attachment and deposition of foreign matter on the intake pipe or the like is greater as the amount of intake air is smaller, so that the shift amount is set to be gradually smaller than the predetermined amount θ as the amount of intake air increases.
[0022]
As described above, by obtaining the relationship between the throttle opening and the intake air amount in the entire throttle opening based on the relationship between the throttle opening and the intake air amount in one specific state, foreign matter to the intake pipe or the like can be obtained. The relationship between the throttle opening and the intake air amount in the entire throttle opening in which the effects of adhesion and deposition are suppressed is required. Therefore, if the throttle valve is changed to a throttle opening degree such that the intake air amount becomes the target intake air amount based on the relationship obtained in this way, even if foreign matter adheres and accumulates on the intake pipe or the like, the actual It is possible to prevent the intake air amount from largely deviating from the target intake air amount.
[0023]
However, the attachment and accumulation of foreign matter on the intake pipe and the like are performed in various forms, and even if the relationship between the detected idle opening and the idle intake air amount is the same, the throttle opening over the entire throttle opening is limited. In many cases, the relationship between the throttle opening and the intake air amount is different, so the relationship between the throttle opening and the intake air amount over the entire throttle opening range can be accurately determined only from the relationship between the detected idle opening and the idle intake air amount. Can not ask. In particular, in the throttle opening range slightly larger than the idle opening, the specific amount is determined according to the form of attachment and accumulation of foreign matter to the throttle valve and the intake pipe around the throttle valve (hereinafter referred to as “throttle valve etc.”). In this throttle opening region, the relationship between the detected throttle opening and the idle intake air amount indicates the relationship between the throttle opening and the intake air amount in the entire throttle opening range. Is particularly difficult to seek. The reason will be described below with reference to the example of FIG.
[0024]
FIGS. 3A and 3B are enlarged views of the vicinity of the throttle valve 18 when foreign matter adheres and accumulates on the intake pipe 15 around the throttle valve 18 in different forms. In particular, the average height (the length in the direction from the inner surface of the intake pipe 15 to the central axis of the intake pipe 15) of the foreign matter adhered and deposited in the form shown in FIG. ) Is higher than the average height of the foreign matter adhering / depositing in the form shown in FIG. In the drawing, the throttle valve 18 having a different throttle opening degree is shown. The throttle valve 18 having a throttle opening degree a is indicated by a broken line, the throttle valve 18 having a throttle opening degree b is indicated by a solid line, and the throttle opening degree is indicated by a solid line. The throttle valve 18 having the degree c is indicated by a chain line. These throttle openings increase in the order of a, b, and c (a <b <c).
[0025]
As can be seen from the figure, the height of the portion where the height of the foreign matter attached and deposited in the form shown in FIG. 3A is the highest (hereinafter, referred to as the “maximum height”) is as shown in FIG. 3) is almost the same as the maximum height of the foreign matter adhering / depositing in the form shown in FIG. 3). For example, when the throttle valve 18 is fully opened (not shown), the foreign matter is shown in FIG. The amount of intake air when foreign matter adheres and deposits in the form shown in FIG. 3B and the amount of intake air when foreign matter adheres and deposits in the form shown in FIG.
[0026]
Further, when the throttle opening is a, the size of the gap between the throttle valve 18 and the foreign matter is large regardless of whether the foreign matter is attached or deposited in any of FIGS. 3 (a) and 3 (b). It doesn't change. Therefore, when the throttle opening is a, the intake air amount hardly changes regardless of the foreign matter adhesion / accumulation form shown in FIGS. 3 (a) and 3 (b).
[0027]
On the other hand, when the throttle opening is b and the foreign matter adheres and accumulates in the form shown in FIG. 3A, the gap between the throttle valve 18 and the foreign matter is small. Therefore, in this case, the intake air amount is slightly larger or hardly changed than when the throttle opening is a. On the other hand, when the foreign matter is attached and deposited in the form shown in FIG. 3B, when the throttle opening is b, the gap between the throttle valve 18 and the foreign matter is the throttle opening. Is greater than a. Further, when the throttle opening is b, the size of the gap when the foreign matter adheres and accumulates in the form shown in FIG. It is smaller than the size of the gap when it is deposited, and its difference (hereinafter, referred to as “gap difference”) or its ratio (hereinafter, referred to as “gap ratio”) is also large. Therefore, when the throttle opening is b, the amount of intake air when foreign matter adheres and accumulates in the form shown in FIG. 3B is determined by the amount of foreign matter adhering and accumulating in the form shown in FIG. It is larger than the amount of intake air in the case of accumulation, and the difference or the ratio is large.
[0028]
Similarly, when the throttle opening is c, the foreign matter adheres and accumulates in the form shown in FIG. 3A and the foreign matter adheres and accumulates in the form shown in FIG. In this case, the gap between the throttle valve 18 and the foreign matter is different, and the intake air amount is also different. However, when the throttle opening is c, the gap ratio is smaller than the gap difference when the throttle opening is b, so that the foreign matter adheres and accumulates in the form shown in FIG. The difference or ratio between the amount of intake air and the amount of intake air when foreign matter adheres and accumulates in the form shown in FIG. 3A is smaller than when the throttle opening is b.
[0029]
From the above, when foreign matter adheres and accumulates in the form shown in FIG. 3A, the relationship between the throttle opening and the intake air amount over the entire throttle opening is represented by the solid line γ in FIG. Become like This solid line γ is not the same as the dashed line β calculated by shifting the dashed-dotted line α which is the relationship between the throttle opening and the intake air amount in the initial state as described above. The broken line β and the solid line γ hardly overlap each other in a slightly larger intake air amount region (that is, a throttle opening region slightly larger than the idle opening amount). Therefore, according to the conventional method of obtaining the relationship between the throttle opening and the intake air amount in the entire throttle opening, this relationship cannot be accurately obtained, particularly in a throttle opening region slightly larger than the idle opening.
[0030]
Therefore, in the intake air amount control device according to the first embodiment of the present invention, the relationship between the throttle opening degree and the intake air amount in the entire throttle opening degree is determined in consideration of the form of adhesion and accumulation of foreign matter, and based on the determined relationship. The throttle opening is controlled in accordance with the target intake air amount. Hereinafter, the intake air amount control device according to the first embodiment of the present invention will be described with reference to FIGS.
[0031]
In the intake air amount control device according to the first embodiment, first, as in the conventional case, the throttle opening with respect to the intake air amount in the initial state is previously calculated as a throttle reference opening taref (ga) by experiment or calculation. To save. Then, when the internal combustion engine is used, the opening degree of the throttle valve 18 is feedback controlled so that the engine speed ne becomes a predetermined constant speed (idle speed) during the engine idling operation after the completion of warm-up. (ISC control). When the ISC control is being performed, the intake air amount is maintained at the idle intake air amount gai. Then, the throttle position ta (gai) with respect to the idle intake air amount gai is detected by the throttle position sensor 19 as the idle opening.
[0032]
In the case where foreign matter has adhered or accumulated on the intake pipe or the like, the idle opening ta (gai) detected as described above is larger than the throttle reference opening taref (gai) corresponding to the idle intake air amount gai. And an amount obtained by subtracting the throttle reference opening degree taref (gai) corresponding to the idling intake air amount gai from the idle opening degree (that is, ta (gai) -taref (gai)) is calculated as the reference correction amount tac1. This reference correction amount tac1 indicates the predetermined amount θ in FIG. Therefore, during the execution of the ISC control, the throttle opening is increased by a predetermined amount θ, so that the idle intake air amount gai can be maintained even if foreign matter adheres or accumulates on the intake pipe or the like. .
[0033]
Then, a value obtained by adding the reference correction amount tac1 to the throttle reference opening degree taref (ga) in the entire intake air amount range is defined as a provisional throttle opening degree of the intake air amount tatem (ga) as shown in FIG. In other words, the provisional throttle opening (tem) (ga) with respect to the intake air amount indicates the broken line β shown in FIG.
[0034]
Further, in the intake / intake air amount control device of the present invention, the intake air amount is detected by the air flow meter 16 at at least one specific throttle opening different from the idle opening. In the present embodiment, the intake air amount is detected at four throttle openings ta1, ta2, ta3, and ta4 greater than the idle opening, and the intake air amounts detected at these four throttle openings are represented by ga1, ga2, and ga, respectively. ga3 and ga4. In the present specification, the above four throttle openings are collectively referred to as tan, and the intake air amount detected at these four throttle openings is collectively referred to as gan.
[0035]
As described above, the intake air amount gan with respect to the specific throttle opening degree tan is, as described above, on the curve of the above-mentioned temporary provisional opening degree item (ga) as shown in FIG. There is no. In this case, the throttle provisional opening degree (tem) corresponding to the specific intake air amount gan is calculated, and the throttle provisional opening degree for the specific intake air amount gan is calculated from the detected throttle opening degree tan for the intake air amount gan. The value obtained by subtracting (gan) is obtained as an error tan '. For example, the error ta1 ′ = ta1−item (ga1). Therefore, when the throttle opening that becomes a specific intake air amount gan is obtained from the provisional throttle opening, it indicates that the obtained throttle opening is shifted by the error tan 'in the specific intake air amount gan.
[0036]
Then, from the relationship between the intake air amount gan and the error tan 'thus obtained, a map of the addition correction amount tac2 (ga) with respect to the intake air amount is created as shown by the solid line in FIG. Such a map is created, for example, by changing the coefficients of the approximate expression based on the calculated error tan '. The solid line in FIG. 6 is a curve of the addition correction amount tac2 (ga) for the intake air amount calculated by changing the coefficient of the fourth-order approximation formula based on the relationship between each intake air amount gan and the error tan '. . The approximation formula may be other than a quartic equation, and any conventional approximation method may be used. Further, instead of the approximate curve, the calculated error tan 'may be calculated in a polygonal line shape as shown by a broken line in FIG.
[0037]
When the throttle opening is controlled so as to actually reach the target intake air amount ga, the target throttle opening tat is set to the provisional throttle opening tatem (gat) corresponding to the target intake air amount ga. It is calculated by adding the addition correction amount tac2 (gat) corresponding to the amount gat (tat = tatem (gat) + tac2 (gat) = taref (gat) + tac1 + tac2 (gat)). By controlling the throttle valve 18 so as to achieve the target throttle opening tat calculated in this way, the actual throttle opening which can obtain the target intake air amount and the provisional throttle opening corresponding to the target intake air amount Is compensated, and the target throttle opening tat can be more accurately controlled by the opening that becomes the target intake air amount. In particular, conventionally, in the throttle opening range slightly larger than the idle opening, the difference between the actual throttle opening at which the target intake air amount is obtained and the provisional throttle opening is large, and the intake air amount is reduced to the target intake air amount. However, by calculating the target throttle opening tat as described above, the throttle opening can be appropriately controlled even in this throttle opening region.
[0038]
Next, a method of detecting the amount of intake air by the air flow meter 16 at four throttle openings larger than the idle opening in the present embodiment will be described. In many internal combustion engines, when the depression amount of the accelerator pedal 40 is zero, control is performed such that fuel is not injected from the fuel injection valve 11 over the entire stroke of the internal combustion engine (hereinafter, referred to as "fuel cut control"). The vehicle equipped with the internal combustion engine is decelerated. While such fuel cut control is executed, the throttle cut 18 is often performed with the throttle valve 18 closed (that is, the throttle opening is zero). However, the throttle valve 18 is slightly opened, or the throttle is opened slightly. Even if the degree is changed, the influence on the operation state of the internal combustion engine is small. Therefore, in the present embodiment, the throttle valve 18 is controlled to a specific throttle opening during execution of the fuel cut control, and the intake air amount corresponding to the throttle opening is detected by the air flow meter 16. By repeating such an operation, the intake air amounts ga1, ga2, ga3, ga4 for the respective throttle openings ta1, ta2, ta3, ta4 are respectively detected. As shown in FIG. 1, in an internal combustion engine capable of performing exhaust gas recirculation (hereinafter, referred to as “EGR”), the intake air amount fluctuates due to the inflow of EGR gas. When detecting the intake air amount, the EGR gas control valve 25 is closed so that the EGR gas does not flow into the intake passage.
[0039]
By the way, during execution of the fuel cut control, the throttle opening is reduced to increase the pumping loss, thereby promoting the deceleration of the vehicle. Therefore, if the throttle opening is increased during execution of the fuel cut control, the vehicle becomes difficult to decelerate. This is remarkable when the engine speed at which the amount of intake air is small is low (that is, when the speed of the vehicle is low). Therefore, if the throttle opening is increased when the engine speed is low, the vehicle becomes very It becomes difficult to decelerate quickly.
[0040]
Thus, in the intake air amount control device of the present embodiment, when the engine speed is relatively low (when the vehicle speed is relatively low), the throttle opening is made relatively small, and this relatively small throttle opening ta1 is used. , Ta2 are detected. On the other hand, when the engine speed is high (when the speed of the vehicle is high), the throttle opening is made relatively large, and the amount of intake air for the relatively large throttle openings ta3 and ta4 is detected. Preferably, the throttle openings ta1 to ta4 are within a throttle opening range slightly larger than the idle opening.
[0041]
Next, a procedure for detecting the idling opening degree ta (gai) in the intake / intake air amount control device of the present embodiment will be described with reference to FIG. FIG. 7 is a flowchart illustrating a control routine of the idle opening detection control. First, in step 101, it is determined whether or not the water temperature wat of the engine cooling water is equal to or higher than a predetermined temperature wat1. This is to determine whether or not the warm-up of the internal combustion engine has been completed. If the water temperature wat is equal to or higher than the predetermined temperature wat1, it means that the warm-up has been completed, and the water temperature wat is lower than the predetermined temperature wat1. In some cases, this means that warm-up has not been completed. It should be noted that the determination of the warm-up completion may not be made based on the water temperature, but may be made based on other criteria such as the bed temperature of the catalyst 22. If it is determined in step 101 that the water temperature wat is lower than the predetermined temperature wat1, the control routine is completed. On the other hand, if it is determined in step 101 that the water temperature wat is equal to or higher than the predetermined temperature wat1, the process proceeds to step 102.
[0042]
In step 102, it is determined whether or not the idling operation condition of the internal combustion engine is satisfied. In the present embodiment, it is determined that the idle operation condition of the internal combustion engine is satisfied because the depression amount of the accelerator pedal 40 detected by the load sensor 41 is zero and the internal combustion engine detected by the vehicle speed sensor. This is a case where the vehicle speed of the vehicle equipped with is zero. If it is determined in step 102 that the idling operation condition of the internal combustion engine is not satisfied, the control routine is terminated. On the other hand, when it is determined in step 102 that the idle operation condition of the internal combustion engine is satisfied, the process proceeds to step 103.
[0043]
In step 103, ISC control is performed. That is, the throttle opening is feedback-controlled so that the engine speed calculated by the crank angle sensor 42 becomes a predetermined speed. As a result, the engine speed is maintained at the predetermined speed, and therefore, the intake air amount is also maintained at the predetermined idle intake air amount gai. Next, at step 104, the throttle position is detected by the throttle position sensor 105. The detected throttle opening is stored in the ROM 33 of the ECU 31 as the idle opening ta (gai), and the control routine is terminated.
[0044]
As described above, according to the idle opening detection control, the relationship between the idle intake air amount gai and the idle opening ta (gai) can be obtained during the engine idle operation after warming up. Although the intake air amount is maintained at the idle intake air amount gai in step 104, the idle intake air amount gai may slightly fluctuate even when the engine speed is the predetermined rotation speed. Therefore, the intake air amount may be detected by the air flow meter 16 in step 103 without setting the idle intake air amount to a predetermined value, and the detected intake air amount may be stored in the ROM 33 of the ECU 31 as the idle intake air amount gai.
[0045]
Next, a procedure for detecting the intake air amount at a predetermined throttle opening will be described with reference to FIG. FIG. 8 is a flowchart showing a control routine of the intake air amount detection control. Step 201 is the same as step 101, and a description thereof will not be repeated. Next, at step 202, it is determined whether or not the fuel cut control is being executed. If it is determined in step 202 that the fuel cut control is not being executed, the control routine is completed. On the other hand, if it is determined in step 202 that the fuel cut control is being executed, the process proceeds to step 203. In step 203, it is determined whether or not the vehicle speed spd of the vehicle equipped with the internal combustion engine is equal to or higher than a predetermined first vehicle speed spd1. The first vehicle speed spd1 is a relatively low vehicle speed. When the vehicle speed spd becomes slower than the first vehicle speed spd1, the engine operation state deteriorates when the throttle opening is changed, or almost decelerates when the throttle valve is opened. The vehicle speed is such that it disappears. If it is determined in step 203 that the vehicle speed spd is lower than the first vehicle speed spd1, the control routine is terminated. On the other hand, if it is determined that the vehicle speed spd is equal to or higher than the first vehicle speed spd1, the process proceeds to step 203. Proceed to 204.
[0046]
In step 204, it is determined whether or not the vehicle speed spd is equal to or less than a predetermined second vehicle speed spd2. The second vehicle speed spd2 is faster than the first vehicle speed spd1. If it is determined in step 204 that the vehicle speed spd is equal to or less than the second vehicle speed spd2, the process proceeds to step 205. In step 205, the throttle opening is the first opening ta1 (= ta (gai) obtained by adding a predetermined first predetermined amount Δta1 to the idle opening ta (gai) detected by the idle opening detecting means. + Δta1), that is, the opening is controlled to be larger by the first predetermined amount Δta1 than the idling opening ta (gai). Next, at step 206, the first intake air amount ga1 is detected by the air flow meter 16 as the intake air amount when the throttle opening is the first opening degree ta1, and the detected first intake air amount ga1 is stored in the ROM 33 of the ECU 31. Is stored in Next, in step 207, the throttle opening is controlled to a second opening ta2 (= ta (gai) + Δta2) obtained by adding a second predetermined amount Δta2 to the idle opening ta (gai). The second predetermined amount Δta2 is larger than the first predetermined amount Δta1 (Δta2> Δta1). Next, at step 208, the second intake air amount ga2 is detected by the air flow meter 16 as the intake air amount when the throttle opening is the second opening ta2, and the detected second intake air amount ga2 is stored in the ROM 33 of the ECU 31. And the control routine is terminated.
[0047]
On the other hand, if it is determined in step 204 that the vehicle speed spd is higher than the second vehicle speed spd2, the process proceeds to step 209. In step 209, the throttle opening is controlled to a third opening ta3 (= ta (gai) + Δta3) obtained by adding a predetermined third predetermined amount Δta3 to the idle opening ta (gai). The third predetermined amount Δta3 is an amount larger than the second predetermined amount Δta2 (Δta3> Δta2). Next, at step 210, the third intake air amount ga3 is detected as the intake air amount for the third opening degree ta3, the detected third intake air amount ga3 is stored in the ROM 33 of the ECU 31, and the routine proceeds to step 211. In step 211, the throttle opening is controlled to a fourth opening ta4 (= ta (gai) + Δta4) obtained by adding a predetermined fourth predetermined amount Δta4 to the idle opening ta (gai). The fourth predetermined amount Δta2 is larger than the third predetermined amount Δta3 (Δta4> Δta3). Next, at step 212, the fourth intake air amount ga4 is detected as the intake air amount for the fourth opening degree ta4, the detected fourth intake air amount ga4 is stored in the ROM 33 of the ECU 31, and the control routine is ended.
[0048]
As described above, according to the intake air amount detection control, when the vehicle speed spd is high (when spd> spd2), the throttle opening is controlled to a relatively large opening (ta3, ta4) to reduce the intake air amount. If the vehicle speed spd is relatively low (spd1 ≦ spd ≦ spd2), the throttle opening is controlled to a relatively small opening (ta1, ta2) to detect the intake air amount. For this reason, the intake air amounts ga1 to ga4 for each of the four specific throttle openings ta1 to ta4 are obtained while maintaining the deceleration of the vehicle (and without deteriorating the engine operation state). That is, four relations between the specific throttle opening and the intake air amount can be obtained.
[0049]
In the intake air amount detection control, the throttle opening is divided into two vehicle speed regions, that is, a vehicle speed region between the first vehicle speed spd1 and the second vehicle speed spd2 and a vehicle speed region higher than the second vehicle speed. The intake air amount is detected by controlling two specific throttle openings, but the vehicle speed region may not be two if it is one or more, and one or more throttles may be provided in each speed region. If the intake air amount is detected based on the opening, the throttle opening may not be two.
[0050]
Further, the first predetermined amount Δta1 to the fourth predetermined amount Δta4 are all relatively small amounts, and the first opening degree ta1 to the fourth opening degree ta4 obtained by adding these predetermined amounts Δta1 to Δta4 to the idle opening degree ta (gai). Is preferably in a throttle opening range slightly larger than the idle opening.
[0051]
In the present embodiment, the intake air amount is detected at four specific throttle openings. However, the intake air amount is not limited to the four specific throttle openings. The air amount may be detected. That is, it suffices if the relationship between the throttle opening and the intake air amount in at least one throttle opening other than the idle opening can be obtained. Alternatively, when the above-described idle opening detection control is not performed and the relationship between the idle opening and the idle intake air amount is not detected, the throttle opening and the suction at at least two specific throttle openings other than the idle opening are determined. What is necessary is just to obtain the relationship with the air amount. Therefore, in the present invention, the relationship between the throttle opening and the intake air amount in at least two specific states may be detected.
[0052]
Further, the detection of the relationship between the throttle opening and the intake air amount in a specific state may be performed by detecting the intake air amount at a specific throttle opening as in the above-described intake air amount detection control. The control may be performed by detecting the throttle opening at a specific intake air amount as in the above-described throttle opening detection control, or a parameter (for example, engine speed) other than the throttle opening or the intake air amount may be constant. May be performed by detecting the throttle opening and the intake air amount, respectively.
[0053]
Next, the relationship between the idle opening degree ta (gai) calculated in the idle opening degree detection control and the idle intake air amount gai, and the throttle opening degree tan and suction in a specific state calculated in the intake air amount detection control. With reference to FIG. 9, description will be given of an addition correction amount map calculation control for creating a map of the addition correction amount with respect to the intake air amount based on the relationship with the air amount tan.
[0054]
First, in step 301, the reference correction amount tac1 is obtained by subtracting the throttle reference opening degree taref (gai) corresponding to the idle intake air amount from the idle opening degree tai calculated by the above-described idle opening detection control. (Tac1 ← gai-taref (gai)). Next, the number of steps n is set to zero. The number of steps n is an integer and is used to represent the first opening degree ta1 to the fourth opening degree ta4 and the first intake air amount ga1 to the fourth intake air amount ga4. For example, when the number of steps n is 2, tan means the second opening degree ta2, and gan means the second intake air amount ga2. Next, in step 303, n + 1 is set to n. Therefore, when step 303 is executed for the first time after the start of the control routine, n is set to 1. In step 304, the provisional throttle opening corresponding to the n-th intake air amount is calculated by adding the reference correction amount tac1 to the throttle reference opening degree taref (gan) corresponding to the n-th intake air amount (tatem ( gan) ← taref (gan) + tac1). Note that the throttle reference opening degree taref (gan) corresponding to the n-th intake air amount is calculated based on a map stored in the ROM 33 of the ECU 31.
[0055]
Next, in step 305, a value obtained by subtracting the provisional throttle opening (tem) (gan) from the n-th opening (tan) is calculated as the n-th error (tan '← tan-tatem (gan)). In step 306, it is determined whether or not the number of steps n is 4 or more. If the number of steps n is less than 4, the process returns to step 303. On the other hand, when the number of steps n is 4 or more, the process proceeds to step 307. Here, the case where the number of steps n is 4 or more means that all of the first error ta1 ′ to the fourth error ta4 ′ have been calculated. Next, at step 307, a coefficient of an approximate expression is obtained from each of the errors ta1 'to ta4' with respect to each of the intake air amounts ga1 to ga4 calculated at steps 303 to 306, whereby the addition correction amount tac2 (ga Is obtained, and the control routine is terminated. Thus, a map of the addition correction amount tac2 (ga) with respect to the intake air amount is obtained.
[0056]
Next, throttle valve control for controlling the throttle valve 18 to the target throttle opening degree tat such that the intake air amount becomes the target intake air amount ga by using the values calculated by the above-described respective controls will be described with reference to FIG. Will be explained. First, in step 401, it is determined whether or not the water temperature wat of the engine cooling water is lower than a predetermined temperature wat1. When it is determined that the water temperature wat is lower than the predetermined temperature wat1, the control routine ends. On the other hand, if it is determined in step 401 that the water temperature wat is equal to or higher than the predetermined temperature wat1, the process proceeds to step 402. In step 402, a target intake air amount ga is calculated according to the engine operating state. More specifically, the target intake air amount ga is calculated based on the water temperature, the oil temperature, the engine speed, the accelerator pedal depression amount, and the like so that the engine operation state is optimized.
[0057]
Next, in step 403, a throttle reference opening tat corresponding to the target intake air amount ga is calculated based on a map previously stored in the ROM 33 of the ECU 31, and the addition correction amount obtained by the addition correction amount map calculation control. Based on the map of tac2 (ga), the addition correction amount tac2 (gat) corresponding to the target intake air amount gat is calculated. Next, in step 404, a value obtained by adding the throttle reference opening degree tat corresponding to the target intake air amount ga, the reference correction amount tac1 calculated in the addition correction amount map calculation control, and the addition correction amount tac2 (gat) is obtained. Is calculated as the target throttle opening tat. Next, at step 405, the throttle valve 18 is controlled to the target throttle opening degree tat, and the control routine is ended.
[0058]
Since the target throttle opening calculated by the target throttle opening calculation control in this way is calculated in consideration of the foreign matter adhering and accumulating around the slot valve 18, the throttle valve 18 is controlled to the target throttle opening. By doing so, the intake air amount can be very accurately set to the target intake air amount.
[0059]
In the above-described embodiment, the reference correction amount tac1 is calculated as a constant value. However, the reference correction amount tac1 may be changed according to the intake air amount. It is preferable to make the size smaller in accordance with the size. In this case, the reference correction amount tac1 (ga) for the specific intake air amount is obtained by adding a correction coefficient K (ga) as shown in FIG. 11 to the reference correction amount tac1 (gai) in the detected idle intake air amount gai. It is calculated by multiplication (tac1 (ga) = K (ga) × tac1 (gai) = K (ga) × {ta (gai) −taref (gai)}. As shown in FIG. 11, the correction coefficient K (ga) changes according to the intake air amount. More specifically, the correction coefficient K (ga) is 1 in the idle intake air amount gai, Also, it decreases as the intake air amount increases. The reason why the reference correction amount tac1 is reduced as the intake air amount increases in this way is that the influence of the attachment and deposition of foreign matter on the intake pipe or the like generally increases as the intake air amount decreases. By changing the amount, it is possible to more accurately determine the throttle opening such that the intake air amount becomes the target intake air amount.
[0060]
In the above embodiment, the provisional throttle opening is calculated from the relationship between the idle opening and the idle intake air amount, and the provisional throttle opening is corrected based on the relationship between the detected intake air amount and the throttle opening. Although the overall relationship between the throttle opening and the intake air amount is determined by using the equation, the direct relationship is obtained from the relationship between the idle opening and the idle intake air amount and the relationship between the throttle opening and the intake air amount in a specific state detected. Alternatively, the overall relationship between the throttle opening and the intake air amount may be obtained.
[0061]
Next, an intake air amount control device according to a second embodiment will be described. The configuration and control method of the intake air amount control device of the second embodiment is basically the same as the configuration and control method of the intake air amount control device of the first embodiment. Different from form. Hereinafter, the intake air amount control in the intake air amount control device of the second embodiment will be described.
[0062]
By the way, as described in the above embodiment, in many internal combustion engines, when the depression amount of the accelerator pedal 40 is zero, the fuel cut control is performed. However, when the fuel cut control is performed, since the fuel is not injected, the lean degree of the air-fuel ratio of the exhaust gas (the ratio of air and fuel supplied to the exhaust passage, the combustion chamber 5 and the intake passage) becomes extremely high. (That is, the air-fuel ratio of the exhaust gas becomes very large). On the other hand, in many catalysts used in internal combustion engines, the deterioration of the catalyst is accelerated when the degree of lean increases. In particular, when the catalyst has a very high bed temperature and the exhaust gas with a large lean degree flows into the catalyst, the catalyst is greatly deteriorated. Therefore, when the bed temperature of the catalyst is high, even if the depression amount of the accelerator pedal 40 is zero and the fuel cut control should be performed, the control for slightly injecting the fuel (hereinafter referred to as “catalyst deterioration suppression control”) ) To prevent the degree of leanness of the exhaust gas from increasing.
[0063]
Even during the execution of the catalyst degradation suppression control, the influence on the engine operating state is small even if the opening degree of the throttle valve is changed in the same manner as during the execution of the fuel cut control described above. Therefore, in the second embodiment of the present invention, the throttle valve is set to a specific throttle opening during execution of the catalyst deterioration suppression control, and the intake air amount corresponding to the throttle opening is detected by the air flow meter 16. Also, even during execution of the catalyst deterioration suppression control, similarly to during execution of the fuel cut control, if the throttle opening is increased when the engine speed is low, the vehicle becomes extremely difficult to decelerate. When the engine speed is relatively low, the throttle opening is relatively small to detect the intake air amount, and when the engine speed is relatively high, the throttle opening is relatively large to detect the intake air amount. .
[0064]
During execution of the catalyst deterioration suppression control, an intake air amount slightly larger than the idle intake air amount is required, and thus the throttle valve is controlled in an opening range slightly larger than the idle opening. By controlling the throttle valve to the target throttle opening calculated in the embodiment, the catalyst deterioration suppression control can be optimally executed.
[0065]
Next, a procedure for detecting an intake air amount at a predetermined throttle opening in the second embodiment will be described with reference to FIG. FIG. 12 is a flowchart illustrating a control routine of intake air amount detection control according to the second embodiment. Step 501 and steps 505 to 512 are the same as steps 201 and steps 205 to 212 shown in FIG.
[0066]
In step 502, it is determined whether or not the catalyst deterioration suppression control is being executed. If it is determined in step 502 that the catalyst deterioration suppression control is not being executed, the control routine is completed. On the other hand, if it is determined in step 502 that the catalyst deterioration suppression control is being executed, the process proceeds to step 503. In step 503, it is determined whether or not the engine speed ne is equal to or greater than a predetermined first speed ne1. The first rotation speed ne1 is a relatively low rotation speed. When the rotation speed ne is lower than the first rotation speed ne1, the throttle valve 18 is not substantially decelerated or accelerated when the throttle valve 18 is opened. It is such a rotation speed. If it is determined in step 503 that the engine speed ne is lower than the first speed ne1, the control routine is terminated, while it is determined that the engine speed ne is equal to or higher than the first speed ne1. In this case, the process proceeds to step 504.
[0067]
In step 504, it is determined whether or not the engine speed ne is equal to or less than a predetermined second speed ne2. The second rotation speed ne2 is a rotation speed higher than the first rotation speed. If it is determined in step 504 that the engine speed ne is equal to or less than the second speed ne2, the process proceeds to step 505. On the other hand, when it is determined in step 504 that the engine speed ne is higher than the second rotation ne2, the process proceeds to step 509.
[0068]
In the above-described embodiment, the relationship between the throttle opening and the intake air amount is detected during the execution of the fuel cut control and the catalyst deterioration suppression control. If the influence on the operating state or the like is small, the above relationship may be detected other than during the execution of the fuel cut control and the catalyst deterioration suppression control.
[0069]
Further, the intake air amount detection control of the second embodiment and the intake air amount detection control of the first embodiment may be performed simultaneously. That is, the intake air amount detection control of the first embodiment may be performed during the execution of the fuel cut control, and the intake air amount detection control of the second embodiment may be performed during the execution of the catalyst deterioration suppression control. Further, the intake air amount detection control of the second embodiment may be combined with the intake air amount detection control of the first embodiment. For example, in each of these embodiments, the throttle air amount may be adjusted according to either the vehicle speed region or the engine speed region. The opening may be set.
[0070]
In the present specification, the intake air amount is described as depending only on the throttle opening, but the intake air amount actually varies depending on the engine speed. Therefore, in the above-described embodiment, when the engine speed is affected, correction is performed based on the engine speed. Therefore, for example, when detecting the intake air amount for a specific throttle opening, the detected intake air amount is corrected by the engine speed, and also when the target throttle opening is obtained from the target intake air amount. A target throttle opening is obtained from a corrected target intake air amount obtained by correcting the target intake air amount with the engine speed.
[0071]
Further, in the above embodiment, the intake air amount is detected by the air flow meter 16, but for example, the intake air amount is determined based on the pressure detected by the intake pressure sensor 20 for detecting the pressure in the surge tank 14. It may be calculated.
[0072]
【The invention's effect】
According to the present invention, the relationship between the throttle opening and the intake air amount in the predetermined throttle opening region is obtained based on the relationship between the throttle opening and the intake air amount in at least two specific states. The relationship between the throttle opening and the intake air amount in the throttle opening range can be obtained more accurately.
[0073]
According to the third aspect, conventionally, the relationship between the throttle opening and the intake air amount in a throttle opening range slightly larger than the idle opening can be accurately obtained.
[0074]
According to the sixth and seventh aspects, it is possible to detect the relationship between the throttle opening and the intake air amount in a state other than during the engine idle operation while minimizing the influence on the engine operation state.
[Brief description of the drawings]
FIG. 1 is a diagram showing an entire internal combustion engine including an intake air amount control device of the present invention.
FIG. 2 is a diagram illustrating a relationship between a throttle opening degree and an intake air amount according to a form of attachment and accumulation of foreign matter.
FIG. 3 is an enlarged view of the vicinity of a throttle valve when foreign matter adhesion / deposition forms are different.
FIG. 4 is a diagram similar to FIG. 2, showing a relationship between a throttle opening and an intake air amount.
FIG. 5 is a diagram illustrating a relationship between a detected throttle opening and an intake air amount.
FIG. 6 is a diagram illustrating a relationship between an intake air amount and an addition correction amount.
FIG. 7 is a flowchart showing a control routine of idle opening detection control.
FIG. 8 is a flowchart showing a control routine of intake air amount detection control.
FIG. 9 is a flowchart illustrating a control routine of addition correction amount map calculation control.
FIG. 10 is a flowchart showing a control routine of target throttle opening calculation control.
FIG. 11 is a diagram showing a map of a correction coefficient with respect to an intake air amount.
FIG. 12 is a flowchart illustrating a control routine of intake air amount detection control according to the second embodiment.
[Explanation of symbols]
1. Engine body
11 ... Fuel injection valve
15 ... Intake duct (intake pipe)
16 ... Air flow meter
18 ... Throttle valve
19 ... Throttle position sensor
31 ... ECU (electronic control unit)
40 ... Accelerator pedal

Claims (7)

A throttle valve provided on the engine intake passage; and detecting means for detecting a relationship between the throttle opening degree and the intake air amount in a specific state, wherein the detecting means detects at least two throttle opening degrees in the specific state. The relationship between the throttle opening and the intake air amount in a predetermined throttle opening region is determined based on the detected relationship, and according to the engine operating state according to the determined relationship. An intake air amount control device that controls the throttle opening to achieve the target intake air amount. 2. The intake air amount control device according to claim 1, wherein the predetermined throttle opening range is the entire throttle opening range. At least one of the relationship between the throttle opening and the intake air amount in the specific state is that the throttle opening is equal to or less than a predetermined throttle opening and is larger than the throttle opening during engine idle operation after warm-up. 3. The intake air amount control device for an internal combustion engine according to claim 1, wherein the intake air amount is detected when the intake air amount is equal to or less than a predetermined intake air amount and is larger than the intake air amount during engine idle operation after warm-up. 4. The intake air amount control device for an internal combustion engine according to claim 3, wherein one of the relationship between the throttle opening degree and the intake air amount in the specific state is detected during an idle operation of the engine after warm-up. 5. The intake air amount control device for an internal combustion engine according to claim 3, wherein the throttle opening is controlled so that the engine speed becomes a predetermined speed during the idle operation of the engine after the warm-up. 6. The intake air amount control device for an internal combustion engine according to claim 1, wherein the detection of the relationship between the throttle opening degree and the intake air amount in the specific state is performed during fuel cut control. A vehicle further comprising a catalyst for purifying exhaust gas of the internal combustion engine, wherein the detection of the relationship between the throttle opening and the intake air amount in the specific state is performed by mounting the internal combustion engine to suppress the deterioration of the catalyst. The intake air amount control device for an internal combustion engine according to any one of claims 1 to 5, wherein the control is performed during the catalyst deterioration suppression control in which the fuel cut control is not performed even during the deceleration of the engine.

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