JP3552475B2 - Control device for internal combustion engine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for an internal combustion engine, and more particularly to a technique for improving torque control accuracy.
[0002]
[Prior art]
2. Description of the Related Art As a conventional torque control device for an internal combustion engine, there is, for example, one disclosed in Japanese Patent Application Laid-Open No. 62-110536.
This torque control device is configured to directly search for a target throttle valve opening from a target engine torque and an engine rotation speed.
[0003]
This is because a predetermined air-fuel ratio (for example, a stoichiometric air-fuel ratio) is set as a premise, and cannot be directly applied to an engine that variably controls the air-fuel ratio according to the operating state.
That is, in order to change the air-fuel ratio while maintaining the same engine operation performance, that is, the same engine speed and engine torque, it is necessary to change both the throttle valve opening and the fuel supply amount. When the fuel ratio is lean, the required intake air amount increases and the required fuel supply amount decreases as compared with the case of the stoichiometric air-fuel ratio, but the conventional device cannot cope with this.
[0004]
The following can be considered as a method for solving such a problem.
In other words, the reference target air amount and the target equivalence ratio at the time of the stoichiometric air-fuel ratio are obtained from the accelerator opening and the engine rotation speed in accordance with the purpose of controlling the target air-fuel ratio and the target torque of the engine while achieving both. The target air amount corresponding to the target air-fuel ratio is obtained, the target throttle valve opening is obtained, and the throttle valve is driven by the throttle valve opening control device, while the basic fuel injection is obtained from the engine speed and the actual intake air amount. The fuel injection valve is driven with the fuel injection pulse width obtained by correcting the pulse width with the target equivalent ratio and the invalid pulse width.
[0005]
[Problems to be solved by the invention]
By the way, when the target air-fuel ratio changes, there is a delay in the change in the intake air amount due to the change in the target throttle valve opening (cylinder intake charging delay). Correspondingly, it is necessary to improve the control accuracy of the engine torque by calculating a second target equivalent ratio in which the phase of the target equivalent ratio is delayed, thereby correcting the basic fuel injection pulse width.
[0006]
However, due to, for example, the response characteristics and calculation timing of the throttle actuator that drives the throttle valve, there is actually a phase delay between the throttle valve opening command value (target throttle valve opening) and the actual throttle valve opening. Exists, and the phase correction of the target equivalence ratio alone due to the delay of the intake air amount does not result in the required phase of the target equivalence ratio, and as a result, the engine torque deviates from the target value.
[0007]
FIG. 10 shows a conventional control in which the target equivalent ratio is corrected in accordance with the cylinder charging delay of the intake air amount in FIG. 10A to calculate the target equivalent ratio tDML (second target equivalent ratio). This indicates that it is impossible to control the target equivalent ratio tDML to correspond to the cylinder intake air amount shown in FIG.
FIG. 11 shows an example of the response characteristics of the above-described throttle actuator. In general, the actual throttle valve opening is expressed by a dead time and a first-order lag with respect to a throttle valve opening signal. You.
[0008]
In this case, the response time constant may change between the opening direction and the closing direction of the throttle valve, or the response time constant itself may change depending on the battery voltage VB as shown in FIG.
In view of the above-described conventional problems, the present invention can control the engine torque to the target value while maintaining the air-fuel ratio at the target value, and can more accurately adjust the engine torque even when the target air-fuel ratio changes. It is an object to provide a control device for an internal combustion engine that can be controlled.
[0009]
[Means for Solving the Problems]
Therefore, the invention according to claim 1 is, as shown in FIG.
Throttle valve driving means for driving a throttle valve interposed in an intake system of the engine;
Fuel supply means for supplying fuel to the engine;
Accelerator operation amount detection means for detecting an accelerator operation amount;
Engine speed detection means for detecting the engine speed,
Intake air amount detection means for detecting an intake air amount to the engine;
Target equivalent ratio calculating means for calculating a target equivalent ratio corresponding to the reference air-fuel ratio / the target air-fuel ratio based on the detected accelerator operation amount and the detected engine speed;
First target equivalent ratio correcting means for correcting the target equivalent ratio in accordance with a phase delay between the target throttle valve opening and the actual throttle valve opening;
Second target equivalence ratio correction means for correcting the target equivalence ratio corrected by the first target equivalence ratio correction means in accordance with the cylinder charging delay of the intake air amount;
Target intake air amount calculating means for calculating a target intake air amount corresponding to the target air-fuel ratio,
A target throttle valve opening calculating means for calculating a target throttle valve opening based on the target intake air amount and the engine rotation speed;
A target equivalent obtained by calculating a basic fuel supply amount corresponding to a reference air-fuel ratio based on the detected intake air amount and the engine rotational speed, and correcting the basic fuel supply amount by the second target equivalent ratio correction means. Fuel supply amount calculating means for calculating the fuel supply amount by correcting based on the ratio,
Throttle valve opening control means for controlling the throttle valve driving means so that the throttle valve opening becomes the calculated target throttle valve opening degree;
Fuel supply amount control means for controlling the fuel supply means so that the fuel supply amount becomes the calculated fuel supply amount;
Is characterized by including.
[0010]
The invention according to claim 2 is
The target intake air amount calculating means calculates a target intake air amount corresponding to a target air-fuel ratio based on a target engine torque and an engine rotation speed.
The invention according to claim 3 is:
The target engine torque is calculated based on an accelerator operation amount and an engine rotation speed or by an external command.
[0011]
The invention according to claim 4 is
Reference target intake air amount calculating means for calculating a reference target intake air amount corresponding to the reference air-fuel ratio based on the detected accelerator operation amount and the detected engine speed,
The target intake air amount calculating means calculates a target intake air amount corresponding to a target air-fuel ratio by dividing the reference target intake air amount by a target equivalent ratio calculated by the target equivalent ratio calculating means. .
[0012]
The invention according to claim 5 is
The first target equivalent ratio correction means is configured based on a correction coefficient as a phase delay between the target throttle valve opening and the actual throttle valve opening, which is set based on a response characteristic of the throttle valve driving means. It is characterized in that the target equivalent ratio is corrected.
The invention according to claim 6 is
The correction coefficient is set using at least one of a battery voltage and a state of a throttle valve as a parameter.
[0013]
The invention according to claim 7 is
The state of the throttle valve is a throttle valve opening direction, a closing direction, and an opening degree.
The invention according to claim 8 is
The first target equivalence ratio correction means corrects the target equivalence ratio by at least one of a dead time correction means and a primary delay correction means.
[0014]
The invention according to claim 9 is
The internal combustion engine uses a fuel injection valve to directly inject fuel into a combustion chamber formed between a piston crown surface, an inner peripheral surface of a cylinder bore, and a lower surface of a cylinder head. It is a spark ignition internal combustion engine.
[0015]
The invention according to claim 10 is
Controlling the intake air amount and the fuel supply amount so that a target engine torque and a target air-fuel ratio corresponding to the operating state of the engine are obtained,
The fuel supply amount is a target equivalent ratio corresponding to a reference air-fuel ratio / a target air-fuel ratio,Set based on the response characteristics of the slot valve driving means,Correcting the basic fuel supply amount based on the target equivalence ratio obtained by correcting the phase delay between the target throttle valve opening and the actual throttle valve opening and the cylinder charging delay of the intake air amount, respectively. It is characterized by being calculated by
In this case, the invention according to claim 11 is characterized in that at least one of a battery voltage and a state of a throttle valve is used as a parameter of a response characteristic of the throttle valve driving means.
[0016]
The operation of the present invention will be described.
In the invention according to claim 1, a target throttle valve opening is calculated based on a target intake air amount and an engine rotation speed corresponding to a target air-fuel ratio, and based on the detected intake air amount and the engine rotation speed. The calculated basic fuel supply amount is corrected based on the target equivalence ratio, and the fuel supply amount is calculated.
[0017]
The throttle valve driving means is controlled so that the throttle valve opening becomes the calculated target throttle valve opening, and the fuel supply means is controlled such that the fuel supply amount becomes the calculated fuel supply amount. Is done.
Therefore, the intake air amount and the fuel supply amount by controlling the throttle valve opening are controlled to respective target values, and the required target engine torque is obtained while maintaining the target air-fuel ratio and satisfying the exhaust purification performance and the like. As a result, good driving performance can be ensured.
[0018]
Then, when the target air-fuel ratio changes, the target equivalent ratio is corrected according to the phase difference between the target throttle valve opening and the actual throttle valve opening, and the corrected target equivalent ratio is further corrected. The intake air amount is corrected in accordance with the cylinder filling delay, and fuel is supplied in accordance with the corrected target equivalence ratio. The torque is accurately controlled.
[0019]
In the invention according to claim 2, the target intake air amount corresponding to the target air-fuel ratio is calculated based on the target engine torque and the engine rotation speed.
In this case, in the invention according to claim 3, the target engine torque is calculated based on the accelerator operation amount and the engine rotation speed or by an external command.
In the invention according to claim 4, a reference target intake air amount corresponding to a reference air-fuel ratio is calculated based on the detected accelerator operation amount and the detected engine speed, and the reference target intake air amount is calculated as a target equivalent ratio. And a target intake air amount corresponding to the target air-fuel ratio is calculated.
[0020]
In the invention according to claim 5, the phase delay between the target throttle valve opening and the actual throttle valve opening depends on the response characteristic of the throttle valve driving means.
Therefore, the target equivalent ratio can be corrected based on a correction coefficient as a phase delay set based on the response characteristic of the throttle valve driving means.
In the invention according to claims 6 and 7, the correction coefficient is set using at least one of the battery voltage and the state of the throttle valve (throttle valve opening direction, closing direction, opening degree) as parameters.
[0021]
In the invention according to claim 8, the target equivalent ratio is corrected by at least one of the dead time correction unit and the first-order delay correction unit.
According to the ninth aspect of the present invention, the fuel is directly injected into the combustion chamber formed between the piston crown surface, the cylinder bore inner peripheral surface, and the cylinder head lower surface by the fuel injection valve, and the fuel is spark-ignited by the spark plug. .
[0022]
In the invention according to claim 10, the intake air amount and the fuel supply amount by controlling the throttle valve opening are controlled to respective target values, and the target air-fuel ratio is maintained while satisfying the exhaust purification performance and the like. A good target engine torque can be obtained, and good driving performance can be secured.
The fuel supply amount is a target equivalent ratio obtained by correcting the target equivalent ratio according to the phase delay between the target throttle valve opening and the actual throttle valve opening and the cylinder charging delay of the intake air amount. The calculation is performed by correcting the basic fuel supply amount based on the ratio, the occurrence of disturbance of the actual engine torque during the change of the air-fuel ratio is prevented, and the engine torque is controlled with high accuracy.
[0023]
【The invention's effect】
According to the first and tenth aspects of the present invention, the intake air amount and the fuel supply amount by controlling the throttle valve opening can be controlled to respective target values, and the exhaust air purification performance and the like can be maintained while maintaining the target air-fuel ratio. It is possible to obtain a required target engine torque while satisfying the conditions, to ensure good driving performance, and to accurately control the engine torque even when the target air-fuel ratio changes.
[0024]
According to the second aspect, the target intake air amount corresponding to the target air-fuel ratio can be easily calculated based on the target engine torque and the engine rotation speed.
In particular, according to the third aspect of the invention, the target engine torque can be easily calculated based on the accelerator operation amount and the engine rotation speed or by an external command.
According to the invention according to claim 4, the target intake air amount corresponding to the target air-fuel ratio can be easily calculated from the reference target intake air amount and the target equivalence ratio.
[0025]
According to the fifth aspect of the present invention, the target equivalence ratio can be easily corrected based on the correction coefficient as a phase delay set based on the response characteristic of the throttle valve driving means.
According to the invention according to claims 6 and 7, the correction coefficient can be variably set using at least one of the battery voltage and the state of the throttle valve (throttle valve opening direction, closing direction, opening degree) as parameters.
[0026]
According to the invention according to claim 8, the correction of the target equivalent ratio can be simplified by at least one of the dead time correction means and the first-order delay correction means.
According to the ninth aspect, the torque controllability of the direct injection type spark ignition internal combustion engine can be improved.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 2 is a system diagram of a direct injection type spark ignition internal combustion engine as an embodiment of the internal combustion engine according to the present invention.
In this figure, a combustion chamber 1 of each cylinder is formed between a cylinder head 2 and a piston 3. On the cylinder head 2 side, an ignition plug 4 is disposed at the center, and an intake port 6 communicating with an intake passage 5 and an exhaust port 8 communicating with an exhaust passage 7 are formed so as to surround the ignition plug 4. 9 and an exhaust valve 10 are provided.
[0028]
A fuel injection valve (injector) 11 as a fuel supply means is provided for each cylinder so as to inject fuel directly into the combustion chamber 1, and fuel is supplied from a fuel gallery common to all cylinders.
The fuel injection valve 11 is an electromagnetic fuel injection valve that is energized and opened by an injection pulse signal from the control unit 12 and is de-energized and closed. The fuel injection amount (fuel Supply amount) is controlled.
[0029]
The control unit 12 includes an engine rotation speed signal from a crank angle sensor 13, an accelerator opening signal from an accelerator sensor 14, and an air flow meter 15 provided in the intake passage 5 for controlling a fuel injection amount and the like. , A cooling water temperature signal from a water temperature sensor 17 mounted on the cylinder block 16, and an oxygen sensor (O₂The sensor 18 receives an oxygen concentration signal and the like.
[0030]
Here, the accelerator sensor 14 as an accelerator operation amount detecting means detects the depression amount of the accelerator pedal depressed by the driver as an engine load (engine torque) desired by the driver.
The crank angle sensor 13 as an engine rotation speed detecting means generates a position signal for each unit crank angle and a reference signal for each cylinder stroke phase difference, and measures the number of position signals generated per unit time, or By measuring the reference signal generation cycle, the engine speed can be detected.
[0031]
The air flow meter 15 as an intake air amount detecting means detects an intake air amount to the engine (an intake air amount per unit time).
A throttle valve 19 is interposed in the intake passage 5, and a throttle actuator 20 is provided as a throttle valve opening driving means capable of electronically controlling the opening of the throttle valve 19.
[0032]
The control unit 12 controls the opening of the throttle valve 19 via the throttle actuator 20 in accordance with the operating state detected based on the signals from the sensors, and drives the fuel injection valve 11 as described above. Thus, the fuel injection amount is controlled, the ignition timing is set, and the ignition plug 4 is ignited at the ignition timing.
[0033]
FIG. 3 shows a functional configuration of an embodiment of the present invention.
An accelerator operation amount APS and an engine rotation speed Ne are input to a reference target intake air amount calculation unit A constituting reference target intake air amount calculation means, and a target engine torque corresponding to an operation state determined by the input values is obtained. The reference target intake air amount tTP is calculated as a value corresponding to the intake air amount obtained at the stoichiometric air-fuel ratio as the reference air-fuel ratio.
[0034]
Specifically, data of the reference target intake air amount tTP obtained experimentally in advance is stored in a map using the accelerator operation amount APS and the engine speed Ne as parameters, and the map is searched for. I do.
The reference target intake air amount tTP includes a basic fuel injection amount (pulse width) corresponding to the intake air amount for each intake stroke, the intake air amount itself for each intake stroke, and a unit detected by the air flow meter. Any amount of intake air per hour may be used.
[0035]
An accelerator operation amount APS and an engine rotation speed Ne are input to a target equivalent ratio calculation unit B which constitutes a target equivalent ratio calculation means, and a target equivalent ratio tDML (to be described later) according to a target air-fuel ratio corresponding to an operating state. 1 target equivalent ratio) is calculated. The target equivalent ratio tDML is basically calculated as reference air-fuel ratio (stoichiometric air-fuel ratio) / target air-fuel ratio, but this value may be corrected by the cooling water temperature Tw.
[0036]
In a target intake air amount calculation unit C as target intake air amount calculation means, the reference target intake air amount tTP is divided by the target equivalent ratio tDML to calculate a target intake air amount tTP 'corresponding to the target air-fuel ratio. I do. The target intake air amount tTP 'corresponding to the target air-fuel ratio is an intake air amount determined so as to obtain the target engine torque at the target air-fuel ratio.
[0037]
The target intake air amount tTP 'and the engine speed Ne are input to a target throttle valve opening calculating section D as a target throttle valve opening calculating means, and a target throttle valve opening tTPS is calculated. The target throttle valve opening tTPS is such that the target intake air amount tTP 'can be obtained.
The signal of the target throttle valve opening tTPS is input to the throttle actuator 20 via the throttle valve opening control unit H, whereby the throttle actuator 20 drives the throttle valve 19 to reach the target throttle valve opening tTPS. I do.
[0038]
Next, the fuel supply amount will be described. The fuel supply amount is calculated by the basic fuel supply amount calculation unit E1 and the correction calculation unit E2 which constitute the fuel supply amount calculation means.
The basic fuel supply amount calculation unit E1 receives the intake air amount Q per unit time detected by the air flow meter 3 and the engine rotation speed Ne, and these are used to calculate one intake air at a stoichiometric air-fuel ratio (reference air-fuel ratio). The basic fuel injection pulse width TP corresponding to the intake air amount per stroke is calculated.
[0039]
The correction calculating unit E2 calculates an effective fuel injection pulse width TE by multiplying the basic fuel injection pulse width TP by a target equivalent ratio tDML ″ (third target equivalent ratio described later). The final fuel injection pulse width TI is calculated by adding the invalid pulse width TS corresponding to the battery voltage to TE.
Then, an injection pulse signal having a fuel injection pulse width TI is output to the fuel injection valve 11 via the fuel supply control unit I, and the fuel injection valve 11 is driven to supply a fuel amount corresponding to the target air-fuel ratio to the engine. It is injected and supplied.
[0040]
On the other hand, the target equivalence ratio tDML (first target equivalence ratio) calculated by the target equivalence ratio calculator B is corrected according to the phase difference between the target throttle valve opening and the actual throttle valve opening. And a first target equivalent ratio corrector G1 as a first target equivalent ratio corrector for obtaining a target equivalent ratio tDML '(second target equivalent ratio), and correction by the first target equivalent ratio corrector G1. A second target equivalent ratio tDML ″ (third target equivalent ratio) is obtained by correcting the target equivalent ratio tDML ′ (second target equivalent ratio) according to the cylinder charging delay of the intake air amount. And a second target equivalence ratio correction unit G2 as target equivalence ratio correction means.
[0041]
In the first target equivalence ratio correction unit G1, the phase difference between the target throttle valve opening and the actual throttle valve opening, which is set based on, for example, the response characteristics of the throttle valve driving means (throttle actuator 20). The target equivalence ratio is corrected based on the correction coefficient.
In this case, the target equivalent ratio is corrected by at least one of the dead time correction unit and the primary delay correction unit such as a weighted average.
[0042]
The correction coefficients in the dead time correction means and the first-order lag correction means are set using the battery voltage and the state of the throttle valve 19 (throttle valve opening direction, closing direction, opening degree) as parameters.
FIG. 4 shows a functional configuration when the target equivalent ratio is corrected by the dead time correction unit G1A as the dead time correction unit and the primary delay correction unit G1B as the primary delay correction unit.
[0043]
The dead time correction unit G1A corrects the target equivalent ratio tDML based on the dead time T (correction coefficient) (tDML0 '[n] = tDML [n-T]), and obtains the corrected target equivalent ratio tDML0'. [N] is output to the first-order lag correction unit G1B.
The primary delay correction unit G1B corrects the target equivalent ratio tDML0 '[n] obtained by the correction in the dead time correction unit G1A based on the weighted average coefficient K (correction coefficient) (tDML' [n] = K · tDML0 ′ [n] + (K−1) · tDML ′ [n−1]) and the corrected target equivalent ratio tDML ′ [n] (second target equivalent ratio) To the target equivalent ratio correction unit G1B.
[0044]
FIG. 5 shows a functional configuration when the dead time T in the dead time correction unit G1A and the weighted average coefficient K in the first-order delay correction unit G1B are set using the battery voltage as a parameter.
That is, there are provided a dead time setting unit K and a weighted average coefficient setting unit L to which the voltage VB signal from the battery J is input, respectively, and a dead time T and a weighted average coefficient output from these setting units K and L, respectively. K is input to the dead time correction unit G1A and the first-order delay correction unit G1B, respectively.
[0045]
In the dead time setting unit K, the dead time T is set based on VB [T = f (VB)], and in the weighted average coefficient setting unit L, the weighted average coefficient K is set based on VB [ K = f (VB)].
FIG. 6 shows the dead time T in the dead time correction unit G1A and the weighted average coefficient K in the first-order delay correction unit G1B, using the state of the throttle valve 19 (for example, the operation direction of the throttle valve (opening direction, closing direction)) as parameters. The functional configuration for setting is shown.
[0046]
That is, there are provided a dead time setting section N and a weighted average coefficient setting section O to which judgment flag signals from a judgment section M as judgment means for judging the operation direction of the throttle valve 19 are respectively inputted. , O, respectively, the dead time T and the weighted average coefficient K are input to the dead time correction unit G1A and the first order delay correction unit G1B, respectively.
In the dead time setting unit N, a dead time T is set based on the operation direction of the throttle valve 19 [opening direction: T = T1, opening direction: T = T2]. The weighted average coefficient K is set based on the operation direction of the valve [opening direction: K = K1, opening direction: K = K2].
[0047]
FIG. 7 shows the dead time T in the dead time correction unit G1A and the weighted average coefficient K in the first order delay correction unit G1B based on the battery voltage and the state of the throttle valve 19 (for example, the operation direction of the throttle valve (opening direction, closing direction)). 2 shows a functional configuration in a case where is set as a parameter.
In this case, the dead time setting unit N provides a map in which the dead time T is allocated in accordance with the battery voltage VB and the operation direction (opening direction, closing direction) of the throttle valve 19, and searches for the dead time T from the map. .
[0048]
Further, the weighted average coefficient setting unit O provides a map in which the weighted average coefficient K is allocated in accordance with the battery voltage VB and the operation direction (opening direction, closing direction) of the throttle valve, and searches the weighted average coefficient K from the map. I do.
FIG. 8 is a flowchart showing the details of the target equivalent ratio correction based on the functional configuration shown in FIG.
[0049]
That is, in step 1 (abbreviated as S1 in the figure; the same applies hereinafter), it is determined whether the target throttle valve opening is larger or smaller than the current throttle valve opening. Since the operation in the opening direction is 19, the operation proceeds to step 2. If the operation is small, the operation in the closing direction is performed on the throttle valve 19, and the operation proceeds to step 3.
In step 2, the open direction side of the dead time setting map and the weighted average coefficient setting map is searched to set the dead time T and the weighted average coefficient K. In step 3, the dead time setting map and the weighted average coefficient setting map are set. , And a dead time T and a weighted average coefficient K are set.
[0050]
In step 4, the target equivalent ratio is corrected based on the dead time T. In step 5, the target equivalent ratio is corrected based on the weighted average coefficient K.
On the other hand, in the second target equivalence ratio correction unit G2, the target equivalence ratio tDML delayed in phase with respect to the target equivalence ratio tDML '(second target equivalence ratio) corrected by the first target equivalence ratio correction unit G1. ″ (Third target equivalent ratio) is calculated.
[0051]
According to the embodiment of the present invention described above, the intake air amount by controlling the throttle valve opening and the fuel supply amount are controlled to respective target values, thereby maintaining the target air-fuel ratio and maintaining the exhaust gas purification performance. It is possible to obtain a required target engine torque while satisfying the conditions and the like, thereby ensuring good driving performance.
When the target air-fuel ratio changes, the target equivalent ratio is corrected in accordance with the phase difference between the target throttle valve opening and the actual throttle valve opening, and the target equivalent ratio tDML '(second target This target equivalent ratio tDML '(second target equivalent ratio) is corrected according to the cylinder charging delay of the intake air amount, and the target equivalent ratio tDML' '(third target equivalent ratio) is corrected. ), And the fuel is supplied in accordance with the target equivalence ratio tDML ″ (third target equivalence ratio). Therefore, it is possible to prevent the occurrence of disturbance in the actual engine torque during the change of the air-fuel ratio, and The torque can be controlled accurately.
[0052]
That is, not only the phase correction of the target equivalence ratio due to the delay of the intake air amount, but also the phase delay between the throttle valve opening command value (target throttle valve opening) and the actual throttle valve opening corresponding to the phase delay. By correcting the equivalence ratio, the phase of the required target equivalence ratio is obtained, and as a result, the engine torque can be controlled without deviating from the target value.
[0053]
FIG. 9 shows a case where the target equivalence ratio tDML is corrected according to the phase difference between the target throttle valve opening and the actual throttle valve opening and the cylinder charging delay of the intake air amount in FIG. FIG. 9B shows the control of the present invention in which a target equivalent ratio tDML ″ (second target equivalent ratio) and a target equivalent ratio tDML ″ (third target equivalent ratio) are calculated. ) Indicates that control corresponding to the cylinder intake air amount can be performed.
[0054]
Also, since the phase difference between the target throttle valve opening and the actual throttle valve opening is not included in the cylinder charging delay of the intake air amount, the two are separated and the target equivalent ratio is corrected. Phase correction of a more appropriate target equivalent ratio can be executed.
Note that a target intake air amount corresponding to the target air-fuel ratio may be calculated based on the target engine torque and the engine speed. In this case, the target engine torque is calculated based on the accelerator operation amount and the engine speed. Alternatively, the calculation may be performed according to an external command.
[Brief description of the drawings]
FIG. 1 is a diagram corresponding to claims of a control device for an internal combustion engine of the present invention.
FIG. 2 is a system diagram of an embodiment of the control device for the internal combustion engine according to the embodiment;
FIG. 3 is a functional configuration diagram of an embodiment of the present invention.
FIG. 4 is a functional configuration diagram for correcting a target equivalent ratio in the embodiment.
FIG. 5 is a functional configuration diagram in a case where a dead time and a weighted average coefficient are set using a battery voltage as a parameter in correcting the target equivalent ratio according to the first embodiment.
FIG. 6 is a functional configuration diagram in a case where a dead time and a weighted average coefficient are set as parameters of a throttle valve in the correction of the target equivalent ratio according to the first embodiment.
FIG. 7 is a functional configuration diagram in a case where a dead time and a weighted average coefficient are set as parameters of a battery voltage and a state of a throttle valve in correcting the target equivalent ratio according to the first embodiment.
FIG. 8 is a flowchart showing correction contents of a target equivalent ratio based on the functional configuration diagram of the above.
FIG. 9 is a time chart for explaining the control of the present invention and its result.
FIG. 10 is a time chart for explaining conventional control and its result.
FIG. 11 is a diagram showing an example of a response characteristic of a throttle actuator.
FIG. 12 is a diagram showing a response time constant depending on a battery voltage.
[Explanation of symbols]
1 combustion chamber
11 Fuel injection valve (injector)
12 Control unit
13 Crank angle sensor
14 Accelerator sensor
15 Air flow meter
19 Throttle valve
20 Throttle actuator
A Reference target intake air amount calculation unit
B Target equivalent ratio calculation unit
C Target intake air amount calculation unit
D Target throttle valve opening calculator
E1 Basic fuel supply calculation unit
E2 Correction calculation unit
G1 First target equivalent ratio correction unit
G2 Second target equivalent ratio correction unit

Claims (11)

Throttle valve driving means for driving a throttle valve interposed in an intake system of the engine;
Fuel supply means for supplying fuel to the engine;
Accelerator operation amount detection means for detecting an accelerator operation amount;
Engine speed detection means for detecting the engine speed,
Intake air amount detection means for detecting an intake air amount to the engine;
Target equivalent ratio calculating means for calculating a target equivalent ratio corresponding to the reference air-fuel ratio / the target air-fuel ratio based on the detected accelerator operation amount and the detected engine speed;
First target equivalent ratio correcting means for correcting the target equivalent ratio in accordance with a phase delay between the target throttle valve opening and the actual throttle valve opening;
Second target equivalence ratio correction means for correcting the target equivalence ratio corrected by the first target equivalence ratio correction means in accordance with the cylinder charging delay of the intake air amount;
Target intake air amount calculating means for calculating a target intake air amount corresponding to the target air-fuel ratio,
Target throttle valve opening calculating means for calculating a target throttle valve opening based on the target intake air amount and the engine rotation speed,
A target equivalent obtained by calculating a basic fuel supply amount corresponding to a reference air-fuel ratio based on the detected intake air amount and the engine rotational speed, and correcting the basic fuel supply amount by the second target equivalent ratio correction means. Fuel supply amount calculating means for calculating the fuel supply amount by correcting based on the ratio,
Throttle valve opening control means for controlling the throttle valve driving means so that the throttle valve opening becomes the calculated target throttle valve opening degree;
Fuel supply amount control means for controlling the fuel supply means so that the fuel supply amount becomes the calculated fuel supply amount;
A control device for an internal combustion engine, comprising: 2. The control device for an internal combustion engine according to claim 1, wherein said target intake air amount calculating means calculates a target intake air amount corresponding to a target air-fuel ratio based on a target engine torque and an engine rotation speed. The control device for an internal combustion engine according to claim 2, wherein the target engine torque is calculated based on an accelerator operation amount and an engine rotation speed or by an external command. Reference target intake air amount calculating means for calculating a reference target intake air amount corresponding to the reference air-fuel ratio based on the detected accelerator operation amount and the detected engine speed,
The target intake air amount calculating means calculates the target intake air amount corresponding to the target air-fuel ratio by dividing the reference target intake air amount by the target equivalent ratio calculated by the target equivalent ratio calculating means. The control device for an internal combustion engine according to claim 1. The first target equivalence ratio correction means is configured based on a correction coefficient as a phase delay between the target throttle valve opening and the actual throttle valve opening, which is set based on a response characteristic of the throttle valve driving means. The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the target equivalent ratio is corrected. 6. The control device for an internal combustion engine according to claim 5, wherein the correction coefficient is set using at least one of a battery voltage and a state of a throttle valve as a parameter. 7. The control device for an internal combustion engine according to claim 6, wherein the states of the throttle valve are a throttle valve opening direction, a closing direction, and an opening degree. The first target equivalence ratio correction means corrects the target equivalence ratio by at least one of a dead time correction means and a first-order delay correction means. Internal combustion engine control device. The internal combustion engine uses a fuel injection valve to directly inject fuel into a combustion chamber formed between a piston crown surface, a cylinder bore inner peripheral surface, and a cylinder head lower surface, and performs in-cylinder direct injection in which spark ignition is performed by a spark plug. The control device for an internal combustion engine according to any one of claims 1 to 8, wherein the control device is a spark ignition internal combustion engine. Controlling the intake air amount and the fuel supply amount such that a target engine torque and a target air-fuel ratio corresponding to the operating state of the engine are obtained,
The fuel supply amount is obtained by setting a target equivalent ratio corresponding to a reference air-fuel ratio / a target air-fuel ratio to a phase between a target throttle valve opening and an actual throttle valve opening , which is set based on a response characteristic of a slot valve driving unit. A control device for an internal combustion engine, wherein the control is performed by correcting a basic fuel supply amount based on a target equivalence ratio obtained by correcting each of the delay amount and the intake air amount according to a cylinder charging delay amount. The control device for an internal combustion engine according to claim 10, wherein at least one of a battery voltage and a state of a throttle valve is used as a parameter of a response characteristic of the throttle valve driving unit.

Images