JP2004285972A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine for preventing deviation of operation performance and exhaust performance. <P>SOLUTION: This control device for an internal combustion engine for estimating concentration of single component of the fuel has an air-fuel ratio computing means for detecting exhaust air-fuel ratio, an air-fuel ratio correction quantity computing means for computing air-fuel ratio correction quantity for correcting the fuel injection quantity on the basis of a detection value of the air-fuel ratio computing means, a first permission determination means for determining permission/inhibition to estimate concentration of the single component of the fuel on the basis of the operation condition, and a second permission determination means for determining permission/ inhibition to estimate concentration of the single component of the fuel on the basis of a result whether the air-fuel ratio correction quantity exists out of the predetermined range or not and for permitting to estimate concentration of the single component of the fuel in the case where the air-fuel ratio correction quantity exists out of the predetermined range. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for an internal combustion engine.
[Prior art]
There is an automobile called a so-called flexible fuel vehicle (FFV) that can run on a mixed fuel of various compositions of alcohol and gasoline in addition to gasoline.
[0003]
Alcohol has a different C (carbon) atom content from normal gasoline (mixed fuel). Therefore, when supplying a mixed fuel of alcohol and gasoline to an internal combustion engine used for a flexible fuel vehicle, the alcohol in the fuel is used. It is necessary to adjust the fuel injection amount according to the concentration.
[0004]
In such a flexible fuel vehicle, the alcohol concentration in the fuel is detected by an alcohol concentration sensor provided in the fuel tank, and when the alcohol concentration sensor fails, the air concentration is calculated based on the exhaust air-fuel ratio. There has been conventionally known a method of estimating an alcohol concentration based on a correlation between an average value of a fuel ratio feedback correction coefficient and an alcohol concentration (see Patent Document 1).
[0005]
[Patent Document 1]
JP-A-5-163992 (pages 1-4, FIG. 5).
[0006]
By the way, when estimating the alcohol concentration in the fuel using the exhaust air-fuel ratio as in the prior art, the exhaust air-fuel ratio is greatly affected by various disturbance factors (for example, blow-by gas or the like). Therefore, when a disturbance factor affecting the exhaust air-fuel ratio occurs, it is conceivable to prohibit the estimation of the alcohol concentration in the fuel using the exhaust air-fuel ratio.
[0007]
[Problems to be solved by the invention]
However, when the alcohol concentration in the fuel changes greatly, such as immediately after refueling with a fuel having a different alcohol concentration, if the alcohol concentration estimation is not performed due to the occurrence of a disturbance factor, the fuel injection is corrected according to the alcohol concentration in the fuel. Since it cannot be performed for the amount, the combustion chamber may fall into an over-lean or over-rich state, and the driving performance and the exhaust performance may be deteriorated.
[Means for Solving the Problems]
The control apparatus for an internal combustion engine according to the present invention includes a first permission determining unit that determines whether to permit or prohibit the estimation of the concentration of a single component in fuel based on an operating state, and whether the air-fuel ratio correction amount is outside a predetermined range. Whether the estimation of the concentration of the single component in the fuel is permitted / prohibited is determined based on whether or not the determination is negative. If the correction amount of the air-fuel ratio for correcting the fuel injection amount is outside a predetermined range, the concentration of the single component in the fuel is estimated. And second permission determining means for permitting
[0009]
【The invention's effect】
According to the present invention, when the air-fuel ratio correction amount is out of the predetermined range, the estimation of the concentration of the single component in the fuel is permitted by the second permission determination means. By using the estimated value, it is possible to prevent the driving performance and the exhaust performance from being deteriorated due to the lack of the air-fuel ratio correction amount.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a schematic configuration of a control device for an internal combustion engine according to one embodiment of the present invention. The internal combustion engine shown in FIG. 1 is an internal combustion engine that uses fuel containing alcohol, and is mounted on a vehicle.
[0011]
An intake passage 4 is connected to the combustion chamber 2 of the engine body 1 via an intake valve 3, and an exhaust passage 6 is connected to the combustion chamber 2 via an exhaust valve 5.
[0012]
In the intake passage 4, an air cleaner 7, an air flow meter 8 for detecting an intake air amount, a throttle valve 9 for controlling the intake air amount, and a fuel injection valve 11 for injecting fuel during intake are arranged.
[0013]
The fuel injection valve 11 injects and supplies fuel during intake so as to attain a predetermined air-fuel ratio in accordance with an operation condition by an injection command signal from an engine control unit 12 (hereinafter, referred to as ECU).
[0014]
The exhaust passage 6 is provided with an oxygen concentration sensor 13 as an air-fuel ratio detecting means that can calculate an air-fuel ratio in the exhaust by detecting the oxygen concentration in the exhaust, and a three-way catalyst 14.
[0015]
The three-way catalyst 14 can simultaneously purify NOx, HC, and CO in the exhaust gas with the maximum conversion efficiency when the air-fuel ratio is in a so-called window centered on the stoichiometric air-fuel ratio. The feedback control of the exhaust air-fuel ratio is performed so that the exhaust air-fuel ratio fluctuates within the range of the above-mentioned window based on the output from the oxygen concentration sensor 13 provided in.
[0016]
The ECU 12 receives a signal from a water temperature sensor 15 that detects the temperature of the cooling water of the engine body 1, and receives a signal from an alcohol concentration input device 16 (which will be described in detail later) as a first fuel property representative value providing unit. Signal can be input.
[0017]
Since fuel containing alcohol has a different C (carbon) atom content from normal gasoline, a large injection amount is required to obtain the same equivalence ratio. When supplying the fuel to the engine, it is necessary to adjust the fuel injection amount according to the alcohol concentration in the fuel.
[0018]
Therefore, in the present embodiment, the concentration of alcohol in the fuel is estimated by the following procedure as the concentration of a single component in the fuel. FIG. 2 shows a flow of control for estimating the alcohol concentration in the fuel.
[0019]
First, in step (hereinafter simply referred to as S) 1, the air-fuel ratio feedback correction coefficient α calculated based on the output signal of the oxygen concentration sensor 13 is calculated.
[0020]
In S2, it is determined whether or not the air-fuel ratio learning condition is satisfied. If the air-fuel ratio learning condition is satisfied, the process proceeds to S3, and the map value of the αm calculation map for each operation region is rewritten. . If the air-fuel ratio learning condition is not satisfied, the process proceeds to S4 without rewriting the map value of each αm calculation map. Here, αm is an air-fuel ratio learning correction coefficient calculated based on α. The air-fuel ratio feedback correction coefficient α and the air-fuel ratio learning correction coefficient αm are the air-fuel ratio correction amounts used for the feedback control of the exhaust air-fuel ratio described above, and the fuel injection amount from the fuel injection valve 11 depends on α and αm. Corrected. In addition, the calculation method of the air-fuel ratio feedback correction coefficient α and the air-fuel ratio learning correction coefficient αm can be any known calculation method, and thus a detailed description of these calculation methods is omitted.
[0021]
In S4, an air-fuel ratio learning correction coefficient αm as an air-fuel ratio correction amount is obtained for each operation region with reference to the current αm map for each operation region.
[0022]
Here, S1 to S4 correspond to the air-fuel ratio correction amount calculating means.
[0023]
In S5 corresponding to the first permission determining means, it is determined whether or not a disturbance affecting the exhaust air-fuel ratio has occurred, that is, whether or not the normal permission condition for performing the alcohol concentration estimation has been satisfied. Specifically, in S5, conditions (operating state) such as the water temperature, the time after engine start, the progress of the air-fuel ratio learning control, the refueling history, and the amount of blow-by gas generated that affects the exhaust air-fuel ratio are equal to or less than a predetermined value. It is determined whether or not the condition is satisfied. If the condition is satisfied, the process proceeds to S6, and if the condition is not satisfied, the process proceeds to S9.
[0024]
In S6, the air-fuel ratio sensitivity correction total amount αt represented by the following equation (1) is calculated.
[0025]
(Equation 1)
αt = α × αm ′ × ETAHOS (1)
Here, ETAHOS is a previous first alcohol concentration estimated value ALC1 (to be described later), that is, a fuel property correction amount calculated from the currently stored first alcohol concentration estimated value ALC1, and will be described later with reference to FIG. , The previous value of αt calculated by reverse lookup from the previous first alcohol concentration estimated value ALC1.
[0026]
Αm ′ in S6 is an average value of αm in a typical rotational load region among αm for each operation region obtained in S4, in other words, αm of approximately four regions frequently used as an engine. Average value.
[0027]
In S7, using the map shown in FIG. 3, the first alcohol concentration estimated value ALC1 as the first single component concentration estimated value is calculated from the air-fuel ratio sensitivity correction total amount αt calculated in S6, and updated.
[0028]
In FIG. 3, the first alcohol concentration estimated value ALC1 has a continuous characteristic with respect to the air-fuel ratio sensitivity correction total amount αt, but this is because the fuel injection is performed in order to maintain the stoichiometric air-fuel ratio. This is a characteristic deposited for realizing a correction in accordance with the air-fuel ratio deviation, that is, the deviation of the air-fuel ratio calculated based on the value detected by the oxygen concentration sensor 13 from the target air-fuel ratio. Further, referring to FIG. 3 in detail, in a state where the air-fuel ratio is leaner than the stoichiometric air-fuel ratio (a region where αt is 100% or more), the air-fuel ratio sensitivity correction total amount αt is equal to the first alcohol concentration estimated value ALC1. When the air-fuel ratio is on the rich side with respect to the stoichiometric air-fuel ratio (a region where αt is 100% or less), the alcohol concentration in the fuel is determined to be 0%. More specifically, when the air-fuel ratio sensitivity correction total amount αt = 100%, the alcohol concentration in the fuel is estimated to be 0%, and when the air-fuel ratio sensitivity correction total amount αt = 140%, the fuel concentration Is estimated to be 85%.
[0029]
In S8, a second alcohol concentration estimated value ALC2 as a second single component concentration estimated value is calculated from the first alcohol concentration estimated value ALC1 calculated in S7 using the ALC2 calculation map shown in FIG. Update.
[0030]
The ALC2 calculation map has a characteristic that the second alcohol concentration estimated value ALC2 has a dead zone with respect to the first alcohol concentration estimated value ALC1. In other words, the ALC2 calculation map indicates that the air-fuel ratio sensitivity correction total amount increases or decreases, that is, the first alcohol concentration estimated value ALC1 There is a dead zone where the second alcohol concentration estimated value ALC2 is substantially constant regardless of the increase or decrease. In the present embodiment, the second alcohol concentration estimated value ALC1 is in the range of 0% to 30%. The estimated value ALC2 is set so as to be uniformly 0%, and in the region where the first alcohol concentration estimated value ALC1 is 65% to 85%, the second alcohol concentration estimated value ALC2 is uniformly set to be 85%.
[0031]
This is because gasoline (that is, E0 fuel with ethanol concentration of 0%) is charged, or a standard blend fuel (gasoline-alcohol fuel), for example, so-called E85 fuel with ethanol concentration of 85% in fuel is always used. If it is entered, it is a characteristic set to use a stable control value (control constant). Here, the control value includes ignition timing-related, fuel wall flow correction-related, cooling increase-related, so-called three-point adjustment constant of λ control, in other words, target air-fuel ratio in air-fuel ratio control, and the like. If these values fluctuate, the reproducibility of the emission deteriorates.
[0032]
The first alcohol concentration estimated value ALC1 calculated in S7 is a combustion parameter that guarantees performance according to the alcohol concentration in the fuel, out of the combustion parameters that require correction based on the alcohol concentration in the fuel, specifically, Is used to correct the basic fuel injection amount (calculated from the engine speed and the intake air amount) calculated according to the operating conditions.
[0033]
Further, the second alcohol concentration estimated value ALC2 calculated in S8 is used for ensuring stable performance with respect to fuels on the market, among the combustion parameters that need to be corrected based on the alcohol concentration in the fuel, and for estimating the actual concentration with respect to the actual concentration. Is used to correct parameters such as the wall flow correction amount, the amount of increase in cooling, the target air-fuel ratio, the ignition timing, and the like, which need to guarantee the deviation of.
[0034]
On the other hand, if it is determined in S5 that the condition is not satisfied, the process proceeds to S9 corresponding to the second permission determination means, and it is determined whether the air-fuel ratio feedback correction coefficient α calculated in S1 is within a predetermined range. . That is, it is determined whether the air-fuel ratio feedback correction coefficient α is in the range of 85% (0.85) or more and 125% (1.25) or less. Proceeds to S10, and if the air-fuel ratio feedback correction coefficient α is within this range, the process ends without performing the alcohol concentration estimation.
[0035]
Here, when the air-fuel ratio feedback correction coefficient α is out of the range of 85% (0.85) or more and 125% (1.25) or less, the normal permission condition is not satisfied in S5 described above.
[0036]
If it is determined in step S9 that the alcohol concentration estimation is not performed (the process does not proceed to step S10), the first alcohol concentration estimation value ALC1 currently stored in the ECU 12 is used without being updated. In addition to correcting the combustion parameter for guaranteeing performance according to the alcohol concentration in the fuel, the correction based on the alcohol concentration in the fuel is performed without using the second alcohol concentration estimation value ALC2 currently stored in the ECU 12 without updating. Among the required combustion parameters, the combustion parameters that require stable performance assurance for marketed fuel and guarantee of the deviation of the estimated concentration from the actual concentration are corrected.
[0037]
In S10, the air-fuel ratio sensitivity correction total amount αt is calculated in the same manner as in S6 described above, and the process proceeds to S11.
[0038]
Then, in S11, the first alcohol concentration estimation value ALC1 is calculated and updated from the air-fuel ratio sensitivity correction total amount αt calculated in S10 using the map shown in FIG. That is, the second alcohol concentration estimated value ALC2 is not updated, and the second alcohol concentration estimated value ALC2 currently stored in the ECU 12 is continuously used.
[0039]
Note that the first alcohol concentration estimated value ALC1 calculated in S11 is, as described above, a combustion parameter that guarantees performance in accordance with the alcohol concentration in the fuel among the combustion parameters requiring correction based on the alcohol concentration in the fuel. It is used when correcting a parameter, specifically, a basic fuel injection amount (calculated from the engine speed and the intake air amount) calculated according to operating conditions.
[0040]
Here, the first alcohol concentration estimated value ALC1 calculated in S7 is used until the first alcohol concentration estimated value ALC1 is calculated in the next S7 or the first alcohol concentration estimated value ALC1 is calculated in S11. It is stored in the ECU 12. Further, the second alcohol concentration estimated value ALC2 calculated in S8 is stored in the ECU 12 until the second alcohol concentration estimated value ALC2 is calculated in next S8.
[0041]
In such a control device for an internal combustion engine, when the estimation of the alcohol concentration in the fuel is permitted in S5, the first alcohol concentration estimation value ALC1 and the second alcohol concentration estimation value ALC2 are calculated and updated, and the first alcohol concentration estimation value ALC2 is updated. The basic fuel injection amount calculated in accordance with the operating condition is corrected using the concentration estimation value ALC1, and the wall flow correction amount, the amount of increase in cooling, and the target, which are the combustion parameters of the internal combustion engine, are corrected using the second alcohol concentration estimation value ALC2. When the air-fuel ratio and the ignition timing are corrected and the estimation of the alcohol concentration in the fuel is permitted in S9, only the first alcohol concentration estimation value ALC1 is calculated and updated, and the calculation and updating of the second alcohol concentration estimation value ALC2 are performed. Not performed.
[0042]
That is, when there is a large deviation between the estimated alcohol concentration value stored in the ECU 12 and the actual alcohol concentration in the fuel in the fuel tank, such as immediately after refueling, a disturbance factor of the alcohol concentration estimation is used. Even when the alcohol concentration estimation is not permitted due to the occurrence of (the case where the normal permission condition of S5 is not satisfied), the first alcohol concentration estimation value ALC1 is calculated and updated, and the updated first alcohol concentration estimation value ALC1 is used. The basic fuel injection amount can be corrected by adjusting the amount of air-fuel ratio correction in the exhaust air-fuel ratio feedback control, and the combustion chamber falls into an over-lean or over-rich state. Can be prevented from becoming worse.
[0043]
In addition, the second alcohol concentration estimated value ALC2 is not updated when the process proceeds to S9 and thereafter (that is, updated only under more certain conditions where the normal permission condition of S5 is satisfied), and thus the second alcohol concentration estimated value ALC2 is described above. 2 The alcohol concentration estimation value ALC2 is appropriate for the intended use.
[0044]
The technical ideas of the present invention that can be grasped from the above embodiments will be listed together with their effects.
[0045]
(1) A control device for an internal combustion engine is for estimating the concentration of a single component in fuel, and is for calculating an air-fuel ratio for detecting an exhaust air-fuel ratio, and an air-fuel ratio correction amount for correcting a fuel injection amount. , An air-fuel ratio correction amount calculating means for calculating the correction amount based on the detection value of the air-fuel ratio calculating means, a first permission determining means for determining permission / prohibition of estimating the concentration of a single component in the fuel based on the operating state, Whether or not the estimation of the concentration of a single component in the fuel is permitted / prohibited is determined based on whether or not the correction amount of the fuel ratio is outside a predetermined range. If the correction amount of the air-fuel ratio is outside the predetermined range, the single composition in the fuel is determined. And second permission determining means for permitting partial concentration estimation. As a result, it is possible to prevent the driving performance and the exhaust performance from being deteriorated due to the insufficient air-fuel ratio correction amount.
[0046]
(2) In the control device for an internal combustion engine according to the above (1), more specifically, the concentration of a single component in the fuel is estimated based on the air-fuel ratio correction amount, and the first permission determination means determines the exhaust gas. It is determined that the estimation of the concentration of a single component is prohibited when a disturbance affecting the air-fuel ratio occurs.
[0047]
(3) More specifically, the control device for an internal combustion engine according to the above (2) is configured such that when the amount of generated blow-by gas is equal to or more than a predetermined value, a disturbance affecting the exhaust air-fuel ratio occurs. judge.
[0048]
(4) In the control device for an internal combustion engine according to any one of the above (1) to (3), more specifically, the second permission determination means calculates the value based on the detection value of the air-fuel ratio detection means. When the value of the air-fuel ratio feedback correction coefficient deviates from 1.0 by a predetermined value or more, estimation of the concentration of a single component in the fuel is permitted.
[0049]
(5) More specifically, the control device for an internal combustion engine according to any one of the above (1) to (4) estimates / updates the concentration of a single component in the fuel, and updates the updated single component. A control device for an internal combustion engine which stores a partial concentration, a fuel property correction amount calculating means for calculating a fuel property correction amount based on a currently stored single component concentration, an air-fuel ratio correction amount and a fuel property. The air-fuel ratio sensitivity correction total amount calculating means for calculating the air-fuel ratio sensitivity correction total amount from the minute correction amount, and the air-fuel ratio sensitivity correction when the exhaust air-fuel ratio detected by the air-fuel ratio detecting means is leaner than the stoichiometric air-fuel ratio. A first single component concentration estimating means for calculating a first single component concentration in which the total amount and the single component concentration estimated value are substantially proportional to each other; Estimation of the concentration of a single component is prohibited, and the second permission determination means When the single component concentration estimation is permitted, the first single component concentration estimation value is calculated by the first single component concentration estimation means, and the operation is performed using the first single component concentration estimation value. The basic fuel injection amount calculated according to the condition is corrected.
[0050]
(6) More specifically, the control device for an internal combustion engine according to any one of (1) to (4) above estimates / updates the concentration of a single component in the fuel and updates the updated single component. A fuel property correction amount calculating means for calculating a fuel property correction amount based on a currently stored single component concentration; an air-fuel ratio correction amount and a fuel property correction; An air-fuel ratio sensitivity correction total amount calculating means for calculating an air-fuel ratio sensitivity correction total amount from the amount, and a first single component concentration for correcting a basic fuel injection amount calculated according to operating conditions, In a state where the exhaust air-fuel ratio detected by the air-fuel ratio detecting means is on the lean side with respect to the stoichiometric air-fuel ratio, the air-fuel ratio sensitivity correction total amount and the first single component concentration estimated value have a substantially proportional relationship. Composition concentration estimating means and a wall which is a combustion parameter of an internal combustion engine The second single component concentration for correcting the flow correction amount, the cooling-time increase amount, the target air-fuel ratio, and the ignition timing is calculated, and the air-fuel ratio calculated based on the detection value of the air-fuel ratio detection means is calculated based on the stoichiometric air-fuel ratio. The second unit having a dead zone in which a second single component concentration estimated value calculated irrespective of an increase or a decrease in the air-fuel ratio sensitivity correction amount is substantially constant in a specific region of the air-fuel ratio sensitivity correction total amount on the lean side with respect to the fuel ratio. Means for estimating the concentration of a single component in the fuel by the first permission determining means. Calculating and updating the component concentration estimation value, calculating and updating the second single component concentration estimation value from the second single component concentration estimation device, and updating the single composition component in the fuel by the first permission determining device. The concentration estimation is prohibited, and the second permission determining means determines the concentration of a single component in the fuel. If the estimation is permitted, the first single composition component concentration estimating means calculates a first single composition component concentration estimates update, updating the second single composition component concentration estimates is not performed.
[0051]
(7) In the control device for an internal combustion engine according to any one of (1) to (6), the single component concentration is an alcohol concentration in the fuel.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel property estimation device for an internal combustion engine according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a flow of control for calculating an estimated alcohol concentration in fuel.
FIG. 3 is an explanatory diagram showing a characteristic example of an ALC1 calculation map.
FIG. 4 is an explanatory diagram showing a characteristic example of an ALC2 calculation map.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine body 2 ... Combustion chamber 3 ... Intake valve 4 ... Intake passage 5 ... Exhaust valve 6 ... Exhaust passage 7 ... Air cleaner 8 ... Air flow meter 9 ... Throttle valve 11 ... Fuel injection valve 12 ... Engine control unit 13 ... Oxygen concentration sensor 14: three-way catalyst 15: water temperature sensor

Claims (7)

In the control device of the internal combustion engine for estimating the concentration of a single component in the fuel,
Air-fuel ratio calculating means for detecting an exhaust air-fuel ratio,
Air-fuel ratio correction amount calculating means for calculating an air-fuel ratio correction amount for correcting the fuel injection amount based on the detection value of the air-fuel ratio calculating means,
First permission determining means for determining permission / prohibition of estimating the concentration of a single component in fuel based on the operating state;
Whether the estimation of the concentration of a single component in the fuel is permitted or prohibited is determined based on whether the air-fuel ratio correction amount is outside the predetermined range. A control device for an internal combustion engine, comprising: second permission determination means for permitting composition concentration estimation. The concentration of the single component in the fuel is estimated based on the air-fuel ratio correction amount, and the first permission determining means prohibits the single component concentration estimation when a disturbance affecting the exhaust air-fuel ratio occurs. The control device for an internal combustion engine according to claim 1, wherein the determination is performed. 3. The control device for an internal combustion engine according to claim 2, wherein when the amount of blow-by gas generated is equal to or greater than a predetermined value, it is determined that a disturbance affecting the exhaust air-fuel ratio has occurred. When the value of the air-fuel ratio feedback correction coefficient calculated based on the detection value of the air-fuel ratio detection unit deviates from 1.0 by a predetermined value or more, the second permission determination unit determines that the single fuel in the fuel The control device for an internal combustion engine according to any one of claims 1 to 3, wherein composition component concentration estimation is permitted. A control device for an internal combustion engine for estimating / updating a single component concentration in a fuel and storing the updated single component concentration,
Fuel property component correction amount calculating means for calculating the fuel property component correction amount based on the single composition component concentration currently stored,
Air-fuel ratio sensitivity correction total amount calculating means for calculating an air-fuel ratio sensitivity correction total amount from the air-fuel ratio correction amount and the fuel property correction amount,
When the exhaust air-fuel ratio detected by the air-fuel ratio detection means is on the lean side with respect to the stoichiometric air-fuel ratio, the air-fuel ratio sensitivity correction total amount and the single-component concentration estimated value have a substantially proportional relationship. And a first single component concentration estimating means for calculating the component concentration.
When the estimation of the concentration of a single component in the fuel is prohibited by the first permission determining means, and the estimation of the concentration of the single component in the fuel is permitted by the second permission determining means, the first concentration estimation of the single component is performed. 2. The method according to claim 1, wherein the first single component concentration estimated value is calculated by the means, and the basic fuel injection amount calculated according to the operating condition is corrected using the first single component concentration estimated value. The control device for an internal combustion engine according to any one of claims 1 to 4. A controller for an internal combustion engine that estimates / updates a single component concentration in a fuel and stores the updated single component concentration,
Fuel property component correction amount calculating means for calculating the fuel property component correction amount based on the single composition component concentration currently stored,
Air-fuel ratio sensitivity correction total amount calculating means for calculating an air-fuel ratio sensitivity correction total amount from the air-fuel ratio correction amount and the fuel property correction amount,
Calculating a first single component concentration for correcting a basic fuel injection amount calculated according to an operating condition, wherein the exhaust air-fuel ratio detected by the air-fuel ratio detecting means is on the lean side with respect to the stoichiometric air-fuel ratio; A first single component concentration estimating means in which the air-fuel ratio sensitivity correction total amount and the first single component concentration estimation value have a substantially proportional relationship in the state of
A second single component concentration for correcting a wall flow correction amount, a cooling time increase amount, a target air-fuel ratio, and an ignition timing, which are combustion parameters of the internal combustion engine, is calculated based on a detection value of an air-fuel ratio detection unit. In the specific region of the air-fuel ratio sensitivity correction total amount where the calculated air-fuel ratio is leaner than the stoichiometric air-fuel ratio, the second single component concentration estimated value calculated regardless of increase or decrease of the air-fuel ratio sensitivity correction total amount is substantially constant. A second single component concentration estimating means having a dead zone to be,
When the first permission determination means permits the estimation of the concentration of the single component in the fuel, the first single composition concentration estimating means calculates and updates the first single component concentration estimation value, Calculating and updating the second single component concentration estimation value from the second single component concentration estimation means;
When the estimation of the concentration of a single component in the fuel is prohibited by the first permission determining means, and the estimation of the concentration of the single component in the fuel is permitted by the second permission determining means, the first concentration estimation of the single component is performed. The internal combustion engine according to any one of claims 1 to 4, wherein the first single component concentration estimated value is calculated and updated by the means, and the second single component concentration estimated value is not updated. Control device. The control device for an internal combustion engine according to any one of claims 1 to 6, wherein the single component concentration is an alcohol concentration in the fuel.

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