JP2002332897A - Control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent operation of unnecessary ignition timing lag control during steady operation. SOLUTION: Required illustrated torque is computed by a required illustrated torque arithmetic means 51 and torque efficiency is computed, corresponding to a target air/fuel ratio by torque efficiency arithmetic means 53, and the required illustrated torque is corrected with the torque efficiency by a corrected torque arithmetic means 54 to find the corrected toque. A target air amount is computed according to the corrected torque by target air amount arithmetic means 55. A lag for the target air amount equivalent to a lag for an intake system is corrected by an intake lag correcting means 61 to find an estimated air amount, and estimated torque is computed according to the estimated air amount by an estimated torque arithmetic means 62, and an ignition timing lag amount is computed in accordance with the estimated torque and the corrected torque, by ignition timing lag amount arithmetic means 63. A final ignition timing is found according to a basic ignition timing which is determined by the operating conditions and the ignition timing lag amount, by an ignition timing arithmetic means 64 and ignition driving means 65 is driven according to the final ignition timing to carry out ignition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine having a function of executing ignition retard control at the time of torque down control or the like.

[0002]

2. Description of the Related Art In recent years, in engine control of an electronically controlled automobile, as disclosed in Japanese Patent Application Laid-Open No. Hei 10-331694, in order to realize drivability with good responsiveness in response to driver's accelerator operation. So-called torque demand control, which determines the acceleration force (requested torque) required by the driver from the accelerator opening and the like operated by the driver and controls the throttle opening, fuel injection amount, ignition timing, and the like accordingly. There's something we did. In such a system, when it is necessary to suddenly reduce the output torque of the engine (for example, when shifting an automatic transmission or operating a traction control system), the required torque is suddenly reduced and the output of the engine is reduced. Torque-down control for rapidly reducing the torque is performed. Generally, torque down control requiring high responsiveness is often performed by ignition retard control that is not affected by a delay (intake delay) until intake air flows into the cylinder.

In the conventional torque demand control system, the actual shaft torque at that time is estimated based on the actual air amount flowing into the cylinder when performing the torque down control, and the deviation between the estimated torque and the required torque is calculated. In some cases, the ignition retard amount is set based on the ignition timing.

[0004]

By the way, if an ideal system is free from error factors such as manufacturing variations and aging, the estimated torque is estimated based on the actual air amount flowing into the cylinder during steady operation. And the required torque coincide with each other, and the steady-state deviation between the two becomes zero. However, in an actual system, due to error factors such as manufacturing variations and aging, the estimated torque and the required torque match even during steady operation. And the steady-state deviation of both does not become zero. For this reason, even during steady operation,
The ignition retard amount is set according to the steady-state error of the estimated torque, and unnecessary ignition retard control is activated, thereby causing problems such as deterioration of fuel efficiency, increase of exhaust emission, and excessive rise of exhaust temperature. there is a possibility.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide an internal combustion engine capable of preventing unnecessary ignition retard control from being operated due to a steady error in estimated torque during steady operation. An object of the present invention is to provide an engine control device.

[0006]

In order to achieve the above object, a control apparatus for an internal combustion engine according to a first aspect of the present invention, based on an accelerator opening or the like operated by a driver as shown in FIG. The required indicated torque to be generated by the combustion of the internal combustion engine is calculated by the required indicated torque calculating means 51, the target air-fuel ratio is set by the target air-fuel ratio setting means 52 according to the operating conditions, and the target efficiency is set by the torque efficiency calculating means 53. The torque efficiency according to the air-fuel ratio is calculated, and the correction torque calculating means 54 corrects the required indicated torque with the torque efficiency to obtain a correction torque. The target air amount is calculated by the target air amount calculating means 55 based on the correction torque, and the target throttle opening degree is calculated by the target throttle opening degree calculating means 56 based on the target air amount. By driving the throttle valve driving means 57, the actual throttle opening is controlled to the target throttle opening.

The intake air delay correcting means 61 corrects the target air amount by a delay corresponding to the delay of the intake system to obtain an estimated air amount, and the estimated torque calculating means 62 calculates an estimated torque based on the estimated air amount. Then, the ignition retard amount calculating means 63 calculates the ignition retard amount based on the estimated torque and the correction torque. Then, the ignition timing calculating means 6
The final ignition timing is obtained based on the basic ignition timing and the ignition retard amount determined from the operation state according to 4 and the ignition driving means 65 is driven according to the final ignition timing to perform ignition.

In this case, the estimated torque is calculated not from the actual air amount but from the air amount (estimated air amount) obtained by correcting the target air amount with the intake delay. Even if the actual air amount varies, the estimated torque can be calculated without being affected by the variation, and the steady-state deviation between the estimated torque and the correction torque (required indicated torque after correction) can be set to 0 in principle. Thus, it is possible to prevent unnecessary ignition retard control from working due to a steady error in the estimated torque during the steady operation.

According to the second aspect of the present invention, as shown in FIG. 9, when calculating the ignition retard amount by the ignition retard amount calculating means 63, the torque efficiency calculated by the torque efficiency calculating means 53 and Using the estimated torque efficiency obtained by delaying the torque efficiency by the intake delay correction means 61 by an amount corresponding to the intake system delay, an ignition retard amount is calculated based on the estimated torque efficiency and the original torque efficiency. . In this case, since the relationship between the estimated torque efficiency and the original torque efficiency corresponds to the relationship between the estimated torque and the correction torque, if the ignition retard amount is calculated based on the estimated torque efficiency and the original torque efficiency, Even if the actual air amount fluctuates due to error factors such as manufacturing variations and changes over time, the steady-state deviation between the estimated torque efficiency and the original torque efficiency can be reduced to zero in principle, without being affected by this. Unnecessary ignition retard control can be prevented from working during operation or deceleration.

According to the third aspect of the present invention, as shown in FIG. 12, when the ignition retard amount is calculated by the ignition delay amount calculating means 63, the target air amount calculated by the target air amount calculating means 55 is calculated. And an estimated air amount obtained by correcting the target air amount by a delay corresponding to the delay of the intake system by the intake delay correction means 61, and determining the ignition retard amount based on the estimated air amount and the target air amount. Calculate. In this case, the relationship between the estimated air amount and the target air amount corresponds to the relationship between the estimated torque and the correction torque. Therefore, if the ignition retard amount is calculated based on the estimated air amount and the target air amount, manufacturing variations Even if the actual air amount fluctuates due to error factors such as time and change over time, the steady-state deviation between the estimated air amount and the target air amount can be reduced to 0 in principle without being affected by the influence. Unnecessary ignition retard control can be prevented from working.

According to the present invention, as shown in FIG. 15, the first target air amount is calculated by the first target air amount calculating means 55a based on the correction torque. And the second target air amount calculating means 66 calculates the second target air amount based on the required indicated torque. And
When calculating the ignition retard amount by the ignition retard amount calculating means 63,
The intake air delay correcting means 61 corrects the first target air amount by a delay corresponding to the delay of the intake system to obtain an estimated air amount. Based on the estimated air amount, the second target air amount, and the torque efficiency, the ignition retard amount is calculated. Is calculated. In this case, when the second target air amount obtained from the required indicated torque and the torque efficiency are combined, information corresponding to the first target air amount obtained from the correction torque is obtained, so that the second target air amount, the torque efficiency and the estimated air amount are obtained. If the ignition retard amount is calculated based on the amount, the estimated air amount and the first target air amount (claim 3)
In this case, the ignition retard amount is calculated based on the target air amount, and the steady-state deviation between the estimated air amount and the first target air amount can be reduced to 0 in principle. Unnecessary ignition retard control can be prevented from working during operation.

In the invention of claim 5, as shown in FIG. 18, the first target air-fuel ratio setting means 52a for setting the first target air-fuel ratio according to the operating condition, and the first target air-fuel ratio setting means 52a according to the operating condition. First ignition retard amount setting means 67 for setting an ignition retard amount
The total torque efficiency is calculated by the total torque efficiency calculating means 69 from the calculation results of the torque efficiency calculating means 53 and 68 for the first target air-fuel ratio and the first ignition retard amount. When calculating the second ignition retard amount by the second ignition delay amount calculating means 71, the total torque efficiency calculated by the total torque efficiency calculating means 69 and the total torque efficiency are calculated by the intake delay correcting means 70. A second ignition retard amount is calculated based on the estimated total torque efficiency and the original total torque efficiency using the estimated total torque efficiency obtained by correcting the delay by an amount equivalent to the delay of the system,
The final ignition timing is obtained based on the basic ignition timing and the second ignition retard amount determined from the operation state. Further, a second target air-fuel ratio is calculated based on the estimated total torque efficiency and the original total torque efficiency, and the fuel injection amount is calculated based on the second target air-fuel ratio and the amount of air flowing into the cylinder. The calculation is performed by the calculation means 59, and a signal corresponding to the calculation result is output to the fuel injection valve driving means 50 to execute the fuel injection.

In this case, the first ignition retard amount is set, for example, when performing early catalyst warm-up control or NOx reduction control.
The final ignition retard amount (second ignition retard amount) is calculated in the same manner as in the above-described second method using the first target air-fuel ratio and the total torque efficiency with respect to the first ignition retard amount. Even if the actual air amount fluctuates due to error factors such as time and change with time, the steady-state deviation between the estimated total torque efficiency and the original total torque efficiency can be reduced to 0 in principle, without being affected by this. Unnecessary ignition retard control can be prevented from working during operation.

Further, in the invention of claim 6, as shown in FIG. 22, the ignition retard amount limiting means 73 limits the second ignition retard amount to a predetermined limit value or less, and the second target air-fuel ratio. The setting means 72 sets the second target air-fuel ratio in consideration of the limit amount of the second ignition retard amount. With this configuration, the second ignition retard amount is set to a value as large as possible within a range where the combustion stability can be ensured, and a torque reduction amount that is insufficient for the ignition retard is secured by the second target air-fuel ratio. This makes it possible to follow the torque-down control with an extremely high response even to a sudden torque-down request.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment (1)] An embodiment (1) of the present invention will be described below with reference to FIGS.

First, a schematic configuration of the entire engine control system will be described with reference to FIG. An air cleaner 13 is provided at the most upstream portion of an intake pipe 12 of an engine 11 which is an internal combustion engine, and an air flow meter 14 for detecting an intake air amount is provided downstream of the air cleaner 13. The motor 1 is located downstream of the air flow meter 14.
A throttle valve 15 driven by an actuator such as 0 and a throttle opening sensor 16 for detecting a throttle opening are provided.

Further, a surge tank 17 is provided downstream of the throttle valve 15.
7, an intake pressure sensor 18 for detecting the intake pressure is provided. The surge tank 17 has an engine 11
An intake manifold 19 for introducing intake air into each cylinder is provided, and a fuel injection valve 20 for injecting fuel is attached near each intake port of the intake manifold 19 of each cylinder.

On the other hand, a catalyst 22 such as a three-way catalyst for purifying CO, HC, NOx and the like in the exhaust gas is provided in the exhaust pipe 21 of the engine 11. An air-fuel ratio sensor 23 (or oxygen sensor) for detecting the air-fuel ratio (or rich / lean) of the exhaust gas is provided upstream of the catalyst 22. The cylinder block of the engine 11 includes:
A cooling water temperature sensor 24 for detecting a cooling water temperature and a crank angle sensor 25 for detecting an engine rotation speed are attached. Further, an accelerator sensor 26 for detecting the opening of the accelerator pedal (accelerator opening) is provided.

The outputs of these various sensors are input to an engine control circuit (hereinafter referred to as "ECU") 27.
The ECU 27 mainly includes a microcomputer, and realizes the functions of the respective units illustrated in FIG. 2 by executing the programs illustrated in FIGS. 3 and 4 stored in a built-in ROM (storage medium). . Here, the function of each means will be described.

The required indicated torque calculating means 51 calculates the required indicated torque based on the output of the accelerator sensor 26 for detecting the opening of the accelerator pedal (accelerator opening).
Here, the required indicated torque is a required value (target value) of the indicated torque, and the indicated torque is a torque generated by combustion of the engine 11, that is, an internal loss torque or an external loss torque of the engine 11 (the load of the auxiliary equipment). ). Therefore, the torque obtained by subtracting the internal loss torque and the external loss torque from the indicated torque becomes the shaft torque (net torque) taken out from the crankshaft of the engine 11, and
The vehicle drive system is driven by this shaft torque.

The required indicated torque calculating means 51 calculates the required shaft torque Tdrv requested by the driver by a map or a mathematical formula based on the output (accelerator opening) of the accelerator sensor 41, the engine speed Ne, and the like, and other required torque. The required shaft torque from the system (for example, the required shaft torque Tcc from the cruise control system, the required shaft torque TTRC from the traction control system, etc.) is calculated to obtain the final required shaft torque Treq.

For example, when torque is required from both the cruise control system and the traction control system, the required shaft torque Tcc from the cruise control system is larger than the required shaft torque Tdrv requested by the driver. The final required shaft torque Treq is determined by comparing the selected required shaft torque with the required shaft torque TTRC from the traction control system and selecting the smaller one.
The required shaft torque Treq is added to the internal loss torque Til.
oss and the external loss torque Tploss are added to obtain the required indicated torque Tindreq (Tindreq = Tiloss + Tploss
).

Here, the internal loss torque is a mechanical friction loss and a pumping loss. The mechanical friction loss is calculated by a map or a mathematical formula based on the engine rotation speed Ne and the cooling water temperature. N
It is calculated by a map or a mathematical expression based on e and the intake pressure. The external loss torque is a load torque of accessories (such as a compressor of an air conditioner, an alternator, and a pump of a power steering) driven by the power of the engine 11, and is calculated according to an air conditioner signal, a load current of the alternator, and the like. You.

The target air-fuel ratio setting means 52 sets an optimum target air-fuel ratio A / Ftgt according to the engine operating conditions.
For example, the engine rotation speed Ne and the required indicated torque Tindr
Based on eq, the optimal target air-fuel ratio A in terms of fuel efficiency, exhaust emissions, and exhaust temperature in the current engine operating state
/ Ftgt is calculated using a map or the like.

The torque efficiency calculating means 53 calculates the torque efficiency λA / F, which is an index indicating the effect of the air-fuel ratio on the torque, using the map shown in FIG. For example, when the air-fuel ratio is stoichiometric (stoichiometric air-fuel ratio), the torque efficiency λA / F is 1.0.

The correction torque calculating means 54 obtains a correction torque Tind by dividing the required indicated torque Tindreq by the torque efficiency λA / F. Tind = Tindreq / λA / F This correction torque Tind corresponds to the required indicated torque obtained by correcting the required indicated torque Tindreq according to the target air-fuel ratio A / Ftgt.

The target air amount calculating means 55 calculates the correction torque T
correction torque T based on ind and engine speed Ne.
The target air amount Gatgt required to realize ind is calculated from a map or the like.

The target throttle opening calculating means 56 calculates the target throttle opening Thrtgt required to realize the target air amount Gatgt based on information such as the target air amount Gatgt, the engine speed Ne, the atmospheric pressure, the intake air temperature and the like. Is calculated by an inverse model of the intake system model or the like, and the target throttle opening T
The actual throttle opening is controlled to the target throttle opening by driving the throttle valve driving means 57 (motor 10) according to hrtgt.

The in-cylinder air amount calculating means 58 flows into the cylinder based on the output of the air flow meter 14 (the amount of air passing through the throttle) and / or the output of the intake pressure sensor 18 (intake pressure) based on an intake system model or the like. Calculated air amount (in-cylinder air amount) Gn is calculated.

The target fuel amount calculating means 59 calculates the target air-fuel ratio A
/ Ftgt is calculated based on the in-cylinder air amount Gn and the target air-fuel ratio A / Ftgt, and the fuel injector driving means 50 is driven in accordance with the target fuel amount Gftgt. Then, the fuel injection is executed. The basic ignition timing calculation means 60 calculates the engine speed Ne and the in-cylinder air amount Gn.
Based on this, the basic ignition timing Sabase is calculated from a map or the like.

On the other hand, the intake air delay correcting means 61 calculates the estimated air amount Gafilt by correcting the target air amount Gatgt calculated by the target air amount calculating means 55 by a delay corresponding to the intake system delay. That is, with respect to the target air amount Gatgt, the air amount actually flowing into the cylinder includes a delay in the intake system (a delay in the electronic throttle system or a delay until the intake air flows into the cylinder).
Therefore, a filter that takes into account the delay of the intake system is applied to the target air amount Gatgt to estimate the amount of air actually flowing into the cylinder (actual in-cylinder air amount).

The estimated torque correction means 62 calculates the estimated air amount G
Based on afilt and the engine speed Ne, the estimated torque Test is calculated by a map or a mathematical expression. Here, since the estimated air amount Gafilt is an estimated value of the actual in-cylinder air amount,
The estimated torque Test obtained from the estimated air amount Gafilt
Corresponds to the estimated value of the actual shaft torque.

The ignition retard amount calculating means 63 calculates the estimated torque T
est and the correction torque Tind based on the ignition retard amount Retar.
Operate on d. At this time, first, the torque efficiency λtgt to be reduced by the ignition retard amount Retard is calculated by the following equation. λtgt = Tindreq / Test / λA / F

Since Tind = Tindreq / λA / F, the torque efficiency λtgt may be calculated by the following equation. λtgt = Tind / Test Then, using the inverse characteristic map of the ignition retard amount-torque efficiency characteristic (see FIG. 6), the ignition retard amount Retard corresponding to the torque efficiency λtgt at that time is calculated.

The ignition timing calculating means 64 obtains the final ignition timing Satgt by subtracting the ignition retard amount Retard from the basic ignition timing Sabase calculated by the basic ignition timing calculating means 60.
The ignition driving means 65 is driven according to the final ignition timing Satgt to execute ignition. The function of each means described above is
3 and 4 executed by the ECU 27. Hereinafter, the processing contents of each program will be described.

The required torque calculation program shown in FIG.
This is a subroutine executed in step 111 of the engine control program of FIG.
Functions as 1. When the program is started, first, in step 101, a required shaft torque Tdrv requested by the driver is calculated by a map or a mathematical formula based on the output of the accelerator sensor 41 (accelerator opening), the engine speed Ne, and the like. In step 102, a required shaft torque Tc from another system is calculated. Thereafter, the routine proceeds to step 103, where the two required shaft torques are added to obtain a final required shaft torque Treq (= Tdrv + Tc).

Thereafter, the routine proceeds to step 104, where the internal loss torque Tiloss is calculated, and in the next step 105, the external loss torque Tploss is calculated. After this, step 10
6, the required shaft torque Treq is added to the internal loss torque Tilos.
The required indicated torque Tindreq is obtained by adding s and the external loss torque Tploss. Tindreq = Tiloss + Tploss

The engine control program shown in FIG. 4 is executed every predetermined time or every predetermined crank angle, and executes throttle control, ignition control and fuel injection control as follows. In the throttle control, first, at step 111, FIG.
The required indicated torque calculation program is executed to calculate the required indicated torque Tindreq. Thereafter, the routine proceeds to step 112, where the optimum target air-fuel ratio A / F is determined based on the engine rotation speed Ne and the required indicated torque Tindreq in terms of fuel efficiency, exhaust emission, and exhaust temperature in the engine operating state at that time.
tgt is calculated using a map or the like.

Thereafter, the routine proceeds to step 113, where the torque efficiency λA / F is used as an index indicating the effect of the air-fuel ratio on the torque.
Is calculated from the map of FIG. 5 according to the target air-fuel ratio A / Ftgt, and in the next step 114, the required indicated torque Tindr
eq is divided by the torque efficiency λA / F to obtain a corrected torque Tind. Tind = Tindreq / λA / F

Thereafter, the routine proceeds to step 115, where the target air amount Gatgt necessary for realizing the correction torque Tind is calculated from a map or the like based on the correction torque Tind and the engine speed Ne. Then, in the next step 116,
Based on information such as the target air amount Gatgt, the engine speed Ne, the atmospheric pressure, and the intake air temperature, the target throttle opening degree Thrtgt required to realize the target air amount Gatgt is calculated by an inverse model of the intake system model or the like. After this, step 1
In step 17, the motor 10 (throttle valve driving means 57) is driven according to the target throttle opening degree Thrtgt to control the actual throttle opening degree to the target throttle opening degree.

On the other hand, in the ignition control, at step 118,
Based on the output of the air flow meter 14 (the amount of air passing through the throttle) and / or the output of the intake pressure sensor 18 (the intake pressure), the amount of air flowing into the cylinder (in-cylinder air amount) Gn is calculated by an intake system model or the like. I do. Thereafter, the process proceeds to a step 119, wherein the basic ignition timing Sabase is obtained from a map or the like based on the engine speed Ne and the in-cylinder air amount Gn.
After the calculation of
The estimated air amount Gafilt (estimated value of the actual in-cylinder air amount) is obtained by delay-correcting the target air amount Gatgt calculated in step 15 by an amount corresponding to the delay of the intake system.

Thereafter, the routine proceeds to step 121, where an estimated torque Test (estimated value of the actual shaft torque) is calculated by a map or a mathematical expression based on the estimated air amount Gafilt and the engine rotation speed Ne. Thereafter, the routine proceeds to step 122, where the ratio between the correction torque Tind and the estimated torque Test (torque efficiency λ
Based on tgt = Tind / Test), an ignition retard amount Retard is calculated using an inverse characteristic map of the ignition retard amount-torque efficiency characteristic (see FIG. 6).

In the next step 123, the final ignition timing Satgt is obtained by subtracting the ignition retard amount Retard from the basic ignition timing Sabase calculated in step 119. Satgt = Sabase-Retard After this, step 12
4 and the ignition driving means 6 according to the final ignition timing Satgt.
5 is driven to perform ignition.

On the other hand, in the fuel injection control, step 125
Then, the target fuel amount Gftgt required to realize the target air-fuel ratio A / Ftgt is determined by the in-cylinder air amount Gn and the target air-fuel ratio A / Ftgt.
Is calculated based on Thereafter, the routine proceeds to step 126, where the fuel injection valve 20 is driven in accordance with the target fuel amount Gftgt to execute fuel injection.

The control behavior of the embodiment (1) described above will be described with reference to FIGS. FIG. 7 is a time chart showing the control behavior when the required indicated torque suddenly decreases due to torque down control or the like. When the target indicated air-fuel ratio is constant and the required indicated torque sharply decreases in a step-like manner, immediately thereafter, the target air amount and the correction torque both sharply decrease in a step-like manner. Increase in shape. As a result, the actual shaft torque sharply decreases following the rapid decrease of the required indicated torque with good response.

In response to the stepwise change in the target air amount, the air amount actually flowing into the cylinder includes a delay in the intake system (a delay in the electronic throttle system or a delay until the intake air flows into the cylinder). ), If the target air amount suddenly drops in a step-like manner, the estimated air amount (estimated value of the actual in-cylinder air amount) decreases with the delay of the intake system, and the estimated torque (real axis) The estimated value of the torque) also decreases with a delay corresponding to the delay of the intake system, and the ignition retard amount also decreases following the decrease in the estimated torque. As a result, the amount of torque reduction due to the ignition retard amount also decreases following the decrease in the shaft torque (estimated torque) due to the decrease in the actual in-cylinder air amount (estimated air amount), and the shaft torque is kept constant.

FIG. 8 is a time chart showing the control behavior when the target air-fuel ratio changes suddenly. When the required indicated torque is constant and the target air-fuel ratio suddenly changes from lean to rich in a step-like manner, immediately thereafter, both the target air amount and the correction torque sharply decrease in a step-like manner. The volume increases stepwise. That is, when the target air-fuel ratio suddenly changes from lean to rich in a step-like manner, the shaft torque tends to increase sharply. Therefore, the increase in the shaft torque is suppressed by increasing the ignition retard amount in a step-like manner.

Also in this case, when the target air amount sharply drops in a step-like manner, the estimated air amount (estimated value of the actual in-cylinder air amount) calculated from the target air amount decreases with a delay of the intake system. Along with that, the estimated torque (estimated value of the actual shaft torque) also decreases with the delay of the intake system,
Following the decrease in the estimated torque, the ignition retard amount also decreases. As a result, the amount of torque reduction due to the ignition retard amount also decreases following the decrease in the shaft torque (estimated torque) due to the decrease in the actual in-cylinder air amount (estimated air amount), and the shaft torque is kept constant.

In the embodiment (1) described above, the estimated torque (estimated value of the actual shaft torque) is not calculated from the actual air amount, but the air amount (estimated air amount) obtained by correcting the target air amount with the intake delay. ), It is possible to calculate the estimated torque without being influenced by the actual air amount, even if the actual air amount varies due to error factors such as manufacturing variations and changes over time. In principle, the steady-state deviation from the indicated torque) can be set to 0, and it is possible to prevent unnecessary ignition retard control from being operated due to the steady-state error of the estimated torque during the steady operation. As a result, it is possible to solve problems such as deterioration of fuel efficiency, increase in exhaust emission, and excessive rise in exhaust temperature due to a steady error in the estimated torque.

[Embodiment (2)] Next, an embodiment (2) of the present invention will be described with reference to FIGS. This embodiment (2) is a modification of the method of calculating the ignition retard amount, and the other points are the same as those of the embodiment (1).

In this embodiment (2), when the ignition retard amount calculating means 63 calculates the ignition retard amount Retard, the torque efficiency λA / F calculated by the torque efficiency calculating means 53 and the torque efficiency λA / F The estimated torque efficiency λA / Ffil obtained by correcting F by a delay corresponding to the delay of the intake system by the intake delay correcting means 61.
Using t, an ignition retard amount Retard is calculated based on the estimated torque efficiency λA / Ffilt and the original torque efficiency λA / F.

Specifically, in step 119 of FIG.
After calculating the basic ignition timing Sabase based on the engine speed Ne and the in-cylinder air amount Gn, the routine proceeds to step 120a, in which the torque efficiency λA / F calculated in step 113 is corrected by a delay corresponding to the delay of the intake system. Estimated torque efficiency λA /
Find Ffilt. Thereafter, the routine proceeds to step 122a, where the ignition retard amount Retard is calculated by a map or the like based on the ratio (λA / Ffilt / λA / F) between the estimated torque efficiency λA / Ffilt and the original torque efficiency λA / F.

Then, in the next step 123, the final ignition timing Satgt is obtained by subtracting the ignition retard amount Retard from the basic ignition timing Sabase calculated in step 119, and the ignition driving means 65 according to this final ignition timing Satgt. Is driven to execute ignition (step 124). Other processes are the same as those in the embodiment (1).

The control behavior of the embodiment (2) described above will be described with reference to FIG. FIG. 11 is a time chart showing the behavior of the control when the target air-fuel ratio changes suddenly. When the required indicated torque is constant and the target air-fuel ratio suddenly changes from lean to rich in a step-like manner, immediately thereafter, the target air amount sharply decreases in a step-like manner, and the ignition retard amount becomes step-like in accordance with the degree of the decrease. To increase. That is, when the target air-fuel ratio suddenly changes from lean to rich in a step-like manner, the shaft torque tends to increase sharply. Therefore, the increase in the shaft torque is suppressed by increasing the ignition retard amount in a step-like manner.

At this time, when the target air-fuel ratio suddenly changes from lean to rich stepwise, immediately thereafter, the torque efficiency obtained from the target air-fuel ratio increases stepwise. As a result, the estimated torque efficiency increases with a delay of the intake system delay, and the ignition retard amount decreases as the ratio between the estimated torque efficiency and the original torque efficiency increases. As a result, the amount of torque reduction due to the ignition retard amount also decreases following the decrease in shaft torque due to the decrease in the actual in-cylinder air amount, and the shaft torque is kept constant.

In the embodiment (2) described above, the ignition retard amount is calculated based on the torque efficiency obtained from the target air-fuel ratio and the estimated torque efficiency obtained by correcting the torque efficiency with delay. Therefore, even if the actual air amount fluctuates due to error factors such as manufacturing variations and changes over time, the steady-state deviation between the estimated torque efficiency and the original torque efficiency can be reduced to 0 in principle without being affected by the fluctuation. In addition, it is possible to prevent unnecessary ignition retard control from working during steady operation or deceleration.

[Embodiment (3)] Next, an embodiment (3) of the present invention will be described with reference to FIGS. This embodiment (3) is a modification of the method of calculating the ignition retard amount, and the other items are the same as those of the embodiment (1).

In the embodiment (3), when the ignition retard amount calculating means 63 calculates the ignition retard amount Retard, the target air amount Gatgt calculated by the target air amount calculating means 55 and the target air amount Gatgt. Is corrected by the intake delay correction means 61 by an amount equivalent to the delay of the intake system, and the ignition delay angle Retard is calculated based on the estimated air amount Gafilt and the target air amount Gatgt. .

Specifically, in step 120 of FIG.
After calculating the estimated air amount Gafilt (estimated value of the actual in-cylinder air amount) by correcting the target air amount Gatgt calculated in step 115 by a delay corresponding to the delay of the intake system, the routine proceeds to step 122b, where the target air amount Gatgt is calculated. Ratio to estimated air amount Gafilt (G
Atgt / Gafilt) is used to calculate the ignition retard amount Retard using a map or the like.

Then, in the next step 123, the final ignition timing Satgt is obtained by subtracting the ignition retard amount Retard from the basic ignition timing Sabase calculated in step 119, and the ignition driving means 65 according to this final ignition timing Satgt. Is driven to execute ignition (step 124). Other processes are the same as those in the embodiment (1).

The behavior of the control of the embodiment (3) described above will be described with reference to FIG. FIG. 14 is a time chart showing the behavior of control when the target air-fuel ratio changes suddenly. When the required indicated torque is constant and the target air-fuel ratio suddenly changes from lean to rich in a step-like manner, immediately thereafter, the target air amount sharply decreases in a step-like manner, and the ignition retard amount becomes step-like in accordance with the degree of the decrease. To increase. That is, when the target air-fuel ratio suddenly changes from lean to rich in a step-like manner, the shaft torque tends to increase sharply. Therefore, the increase in the shaft torque is suppressed by increasing the ignition retard amount in a step-like manner.

At this time, if the target air amount drops abruptly in steps, the estimated air amount (estimated value of the actual in-cylinder air amount) decreases with a delay of the intake system, and the target air amount and the estimated air amount As the ratio increases, the ignition retard amount decreases. As a result, the amount of torque reduction due to the ignition retard amount also decreases following the decrease in shaft torque due to the decrease in the actual in-cylinder air amount, and the shaft torque is kept constant.

According to the embodiment (3) described above,
Since the ignition retard amount is calculated based on the target air amount and the estimated air amount estimated from the target air amount, even if the actual air amount fluctuates due to error factors such as manufacturing variations and aging. Without being affected by the influence, the steady-state deviation between the estimated air amount and the target air amount can be reduced to 0 in principle, and unnecessary ignition retard control can be prevented from working during steady operation or deceleration. .

[Embodiment (4)] Next, an embodiment (4) of the present invention will be described with reference to FIGS. This embodiment (4) is a modification of the method of calculating the ignition retard amount, and the other items are the same as those of the above-described embodiment (1).

In this embodiment (4), the first target air amount calculating means 55a calculates the first target air amount Gatgt based on the correction torque Tind, and the target throttle opening based on the first target air amount Gatgt. Calculate the degree Thrtgt,
The requested indicated torque T is calculated by the second target air amount calculating means 66.
A second target air amount Garef is calculated based on indreq. When calculating the ignition retard amount Retard by the ignition retard amount calculating means 63, the intake air delay correcting means 61 corrects the first target air amount Gatgt by a delay corresponding to the delay of the intake system to reduce the estimated air amount Gafilt. Then, the ignition retard amount Retard is calculated based on the estimated air amount Gafilt, the second target air amount Garef, and the torque efficiency λA / F.

Specifically, in step 114 of FIG.
After calculating the correction torque Tind by dividing the required indicated torque Tindreq by the torque efficiency λA / F, the routine proceeds to step 115a, where the necessary torque for realizing the correction torque Tind is determined based on the correction torque Tind and the engine speed Ne. 1) Calculate the target air amount Gatgt using a map or the like, and
At 16, a target throttle opening degree Thrtgt is calculated based on the target air amount Gatgt, the engine speed Ne, and the like.

On the other hand, in step 120,
An estimated air amount Gafilt (estimated value of the actual in-cylinder air amount) is obtained by delay-correcting the first target air amount Gatgt calculated in 15a by an amount corresponding to the delay of the intake system.

Thereafter, the routine proceeds to step 121a, where the second target air amount Garef is calculated by a map or a mathematical expression based on the required indicated torque Tindreq and the engine speed Ne. Thereafter, the routine proceeds to step 122c, in which the ignition retard amount Retard is calculated by a map or the like based on the ratio (Garef / Gafilt / λA / F) of the second target air amount Garef, the estimated air amount Gafilt, and the torque efficiency λA / F. I do. Then, in the next step 123, the final ignition timing Satgt is obtained by subtracting the ignition retard amount Retard from the basic ignition timing Sabase calculated in step 119, and the ignition driving means 65 is driven according to this final ignition timing Satgt. To perform ignition (step 12
4). Other processes are the same as those in the embodiment (1).

The control behavior of the embodiment (4) described above will be described with reference to FIG. FIG. 17 is a time chart showing a control behavior when the target air-fuel ratio changes suddenly. When the required indicated torque is constant and the target air-fuel ratio suddenly changes from lean to rich in a step-like manner, the first target air amount sharply drops in a step-like manner, and the estimated air amount calculated from the first target air amount (actual cylinder amount) (The estimated value of the internal air amount) decreases with the delay of the intake system, but since the second target air amount is calculated based on the required indicated torque, the target air-fuel ratio suddenly changes stepwise from lean to rich. Even if the required indicated torque is constant, the second target air amount does not change.
At this time, when the target air-fuel ratio suddenly changes from lean to rich in a step-like manner, immediately thereafter, the torque efficiency obtained from the target air-fuel ratio increases in a step-like manner.

For this reason, when the target air-fuel ratio suddenly changes stepwise from lean to rich, the ratio of the second target air amount, the estimated air amount, and the torque efficiency (second target air amount / estimated air amount /
(Torque efficiency) sharply decreases, and the ignition retard amount increases stepwise according to the degree of the decrease. That is, when the target air-fuel ratio suddenly changes from lean to rich in a step-like manner, the shaft torque tends to increase sharply. Therefore, the increase in the shaft torque is suppressed by increasing the ignition retard amount in a step-like manner. Then, the ratio between the second target air amount, the estimated air amount, and the torque efficiency also decreases with the delay of the intake system following the decrease of the estimated air amount with the delay of the intake system. , The amount of torque reduction due to the ignition retard amount also decreases,
The shaft torque is kept constant.

In the embodiment (4) described above, the ignition retard amount is calculated based on the estimated air amount, the second target air amount, and the torque efficiency. When the torque efficiency is combined with the information, the information corresponding to the first target air amount obtained from the correction torque is obtained. Therefore, if the ignition retard amount is calculated based on the second target air amount, the torque efficiency, and the estimated air amount, Similar to the embodiment (3), the calculation of the ignition retard amount based on the estimated air amount and the first target air amount is substantially the same, and a steady-state deviation between the estimated air amount and the first target air amount. Can be set to 0 in principle, and unnecessary ignition retard control can be prevented from working during steady operation or deceleration.

[Embodiment (5)] Next, an embodiment (5) of the present invention will be described with reference to FIGS. The fifth embodiment is different from the first embodiment in that the method of calculating the ignition retard amount and the target fuel amount is changed.

In this embodiment (5), the first target air-fuel ratio setting means 52a for setting the first target air-fuel ratio A / Ftgt (1) according to the operating conditions, and the first ignition retard according to the operating conditions Quantity R
a first ignition retard amount setting means 67 for setting etard (1), and a torque efficiency calculating means 53 for the first target air-fuel ratio A / Ftgt (1) and the first ignition retard amount Retard (1). From the calculation result of 68, the total torque efficiency λtotal is calculated by the total torque efficiency calculation means 69. When the second ignition retard amount calculating means 71 calculates the second ignition retard amount Retard (2), the total torque efficiency λtotal calculated by the total torque efficiency calculating means 69 and the total torque efficiency λtotal are taken into the intake air. Based on the estimated total torque efficiency λfilt and the original total torque efficiency λtotal, the estimated total torque efficiency λfilt obtained by delay correction by the delay correction means 70 by the delay corresponding to the intake system delay is used.
The ignition retard amount Retard (2) is calculated, and the second ignition retard amount Retard (2) is subtracted from the basic ignition timing Sabase determined from the operating state to obtain the final ignition timing Satgt.
The ignition driving means 65 is driven according to atgt to execute ignition.

Also, based on the estimated total torque efficiency λfilt and the original total torque efficiency λtotal, the second target air-fuel ratio A / Ftg
t (2) is calculated, and the target fuel amount Gftgt is calculated by the fuel injection amount calculating means 59 based on the second target air-fuel ratio A / Ftgt (2) and the amount of air Gn flowing into the cylinder. A signal corresponding to the result is output to the fuel injection valve driving means 50 to execute the fuel injection.

The function of each means described above is performed by the ECU 27
Are executed by the engine control program of FIG. 19 and FIG. When the program is started, first, in step 201, the required indicated torque calculation program of FIG. 3 described above is executed to calculate the required indicated torque Tindreq. Thereafter, the routine proceeds to step 202, where the first target air-fuel ratio A / Ftgt (1) is determined based on the engine rotational speed Ne and the required indicated torque Tindreq in the engine operating state at that time, from the viewpoints of fuel efficiency, exhaust emission, and exhaust temperature. ) Is calculated using a map or the like.

Thereafter, the routine proceeds to step 203, where the air-fuel ratio torque efficiency λA / F, which is an index indicating the effect of the air-fuel ratio on the torque, is calculated according to the first target air-fuel ratio A / Ftgt (1) in the map of FIG. In the next step 204, the first ignition retard amount Retard (1) is calculated according to the operating conditions. The first ignition retard amount Retard (1) is set, for example, when performing early catalyst warm-up control or NOx reduction control.

Then, in the next step 205, the ignition timing torque efficiency λSA is calculated from a map or the like according to the first ignition retard amount Retard (1). Thereafter, the routine proceeds to step 206, where the air-fuel ratio torque efficiency λA / F and the ignition timing torque efficiency λSA
To obtain the total torque efficiency λtotal. λtotal = λA / F × λSA

Thereafter, the routine proceeds to step 207, where the required indicated torque Tindreq is divided by the total torque efficiency λtotal to calculate the correction torque Tind. Tind = Tindreq / λtotal

Thereafter, the routine proceeds to step 208, where the target air amount Gatgt necessary for realizing the correction torque Tind is calculated from a map or the like based on the correction torque Tind and the engine speed Ne. Then, in the next step 209,
Based on information such as the target air amount Gatgt, the engine speed Ne, the atmospheric pressure, and the intake air temperature, the target throttle opening degree Thrtgt required to realize the target air amount Gatgt is calculated by an inverse model of the intake system model or the like. After this, step 2
In step 10, the motor 10 (throttle valve driving means 57) is driven according to the target throttle opening degree Thrtgt to control the actual throttle opening degree to the target throttle opening degree.

On the other hand, in the ignition control, step 2 in FIG.
In step 11, the total torque efficiency λ calculated in step 206
Total is corrected by a delay corresponding to the delay of the intake system to obtain an estimated total torque efficiency λfilt. Thereafter, the routine proceeds to step 212, where the ignition retarding efficiency λSAtgt is calculated as the estimated total torque efficiency λfilt,
Original total torque efficiency λtotal, ignition timing torque efficiency λSA,
It is calculated by the following equation using the distribution coefficient α. λSAtgt = λfilt / λtotal / λSA × α

Here, the distribution coefficient α is the second ignition retard amount R
torque reduction by etard (2) and second target air-fuel ratio A / Ftg
It is a coefficient that determines the distribution ratio with the torque down due to t (2), and is set to a value in the range of λtotal <α <1.

Then, in the next step 213, the second ignition retard amount Retard (2) is calculated by a map or a mathematical expression according to the ignition retarding efficiency λSAtgt. Thereafter, step 214
The basic ignition timing Sabase is calculated by a map or the like based on the engine rotation speed Ne and the in-cylinder air amount Gn calculated in step 217, and in the next step 215, the second ignition retard amount is calculated from the basic ignition timing Sabase. The final ignition timing Satgt is obtained by subtracting Retard (2).

Satgt = Sabase−Retard (2) Thereafter, the routine proceeds to step 216, where the ignition drive means 65 is driven according to the final ignition timing Satgt to perform ignition.

On the other hand, in the fuel injection control, step 217 is executed.
Then, based on the output of the air flow meter 14 (the amount of air passing through the throttle) and / or the output of the intake pressure sensor 18 (the intake pressure), the amount of air (in-cylinder air amount) Gn flowing into the cylinder by an intake system model or the like. Is calculated. Thereafter, the routine proceeds to step 218, where the target air-fuel ratio efficiency λA / Ftgt is obtained by dividing the ignition retarding efficiency λSAtgt by the distribution coefficient α. λA / Ftgt = λSAtgt / α

Thereafter, the routine proceeds to step 219, where the second target air-fuel ratio A / Ftgt (2) is calculated from a map or the like according to the target air-fuel ratio efficiency λA / Ftgt. Then, the next step 220
Then, a target fuel amount Gftgt required to realize the second target air-fuel ratio A / Ftgt (2) is calculated based on the in-cylinder air amount Gn and the second target air-fuel ratio A / Ftgt (2). Thereafter, the process proceeds to step 221, where the fuel injection valve 2 is set in accordance with the target fuel amount Gftgt.
0 is driven to execute fuel injection.

The control behavior of the embodiment (5) described above will be described with reference to FIG. FIG. 21 is a time chart showing a control behavior when the first target air-fuel ratio changes suddenly. The requested indicated torque and the first ignition retard amount are constant, and the first
When the target air-fuel ratio suddenly changes from lean to rich in a step-like manner, the shaft torque is kept constant by the torque reduction by the second ignition retard amount and the torque reduction by the second target air-fuel ratio. At this time, the distribution ratio between the torque reduction due to the second ignition retard amount and the torque reduction due to the second target air-fuel ratio is determined by a preset distribution coefficient α.

That is, when the required indicated torque and the first ignition retard amount are constant and the first target air-fuel ratio suddenly changes from lean to rich in a step-like manner, the target air amount sharply decreases in a step-like manner and the ignition retard The efficiency also sharply decreases in a step-like manner, and the second ignition retard amount increases in a step-like manner in accordance with the decrease width, thereby suppressing an increase in the shaft torque. Then, as the ignition retarding efficiency returns to the original value (1) with a delay corresponding to the delay of the intake system, the amount of torque reduction due to the amount of ignition retardation decreases and the amount of torque reduction due to the second target air-fuel ratio also decreases. As a result, the shaft torque is kept constant.

In the embodiment (5) described above, the first
Since the final ignition retard amount (second ignition retard amount) is calculated using the target air-fuel ratio and the total torque efficiency with respect to the first ignition retard amount in the same manner as in the embodiment (2), manufacturing Even if the actual air amount fluctuates due to error factors such as variations and changes over time, the steady-state deviation between the estimated total torque efficiency and the original total torque efficiency can be set to 0 in principle without being affected by the actual air amount. Unnecessary ignition retard control can be prevented from working during steady operation or deceleration.

[Embodiment (6)] Next, an embodiment (6) of the present invention will be described with reference to FIGS. In the present embodiment (6), as shown in FIG. 22, the ignition retarding efficiency limiting means 73 limits the ignition retarding efficiency λSAtgt to a predetermined limit value λSAmin, thereby providing a second ignition retarding quantity Retard.
(2) is limited to a range in which the combustion stability can be ensured, and the second target air-fuel ratio A is set by the second target air-fuel ratio setting means 72 in consideration of the limit amount of the second ignition retard amount Retard (2). /
Set Ftgt (2). Other items are the same as those of the embodiment (5).

More specifically, in step 212 of FIG.
The ignition retarding efficiency λSAtgto is calculated using the estimated total torque efficiency λfilt, the original total torque efficiency λtotal, the ignition timing torque efficiency λSA, and the distribution coefficient α. λSAtgto = λfilt / λtotal / λSA × α

Thereafter, the routine proceeds to step 212a, where the ignition retarding efficiency λSAtgto is reduced to a predetermined limit value λ
Guard processing is performed with SAmin (corresponding to a value near the limit of the range in which combustion stability can be ensured). If the ignition retarding efficiency λSAtgto calculated in step 212 is equal to or greater than the limit value λSAmin, the guard process sets the ignition retarding efficiency λSAtgto as it is to the final ignition retarding efficiency λSAtgt (λSAtg
t = λSAtgto), ignition retarding efficiency λSAtgto is the limit value λSAmi
If it is smaller than n, the limit value λSAmin is set to the final ignition retarding efficiency λSAtgt (λSAtgt = λSAmin). Then, in the next step 213, a second ignition retard amount Retard (2) is calculated by a map or a mathematical expression according to the final ignition retard efficiency λSAtgt.

On the other hand, in step 217, the amount of air Gn flowing into the cylinder (in-cylinder air amount) Gn is calculated by an intake system model or the like, and the process proceeds to step 218a, where the total torque efficiency λto
The target air-fuel ratio efficiency λA / Ftgt is obtained by dividing the estimated total torque efficiency λfilt obtained by correcting tal by the delay corresponding to the intake system delay by the ignition retarding efficiency λSAtgt. λA / Ftgt = λfilt / λSAtgt

Then, in the next step 213, the second ignition retard amount Retard (2) is calculated by a map or a mathematical expression in accordance with the ignition retarding efficiency λSAtgt. Other processes are the same as those in the embodiment (5).

The control behavior of the embodiment (6) described above will be described with reference to FIG. FIG. 24 is a time chart showing a control behavior when the first target air-fuel ratio changes suddenly. The requested indicated torque and the first ignition retard amount are constant, and the first
When the target air-fuel ratio suddenly changes from lean to rich in a step-like manner, first, a torque reduction amount is secured by the second ignition retarding amount within the range of the ignition retarding efficiency, and the ignition retarding amount is insufficient. Is secured by the second target air-fuel ratio, and the shaft torque is kept constant.

That is, when the required indicated torque and the first ignition retard amount are constant and the first target air-fuel ratio suddenly changes from lean to rich in a step-like manner, the target air amount sharply drops in a step-like manner, and the ignition retardation is also reduced. The efficiency also drops sharply in steps. Thereby, when the ignition retarding efficiency becomes equal to or less than the limit value as shown by the dotted line, the ignition retarding efficiency is limited by the limit value, and the second ignition retarding amount is limited. An insufficient amount of torque reduction is secured by the second target air-fuel ratio by only the torque reduction by the second ignition retard amount. Then, as the ignition retarding efficiency returns to the original value (1) with a delay corresponding to the delay of the intake system, the amount of torque reduction due to the ignition retarding amount also decreases, and the ignition retarding efficiency decreases according to the second target air-fuel ratio. The amount of torque reduction also decreases, and the shaft torque is kept constant.

In the embodiment (6) described above, the second ignition retard amount is set as large as possible within a range in which the combustion stability can be ensured, and the torque reduction amount that is not sufficient for the ignition retard angle is set. Can be ensured by the second target air-fuel ratio, and the torque-down control can be made to follow the response with extremely high response to a sudden torque-down request.

The present invention is not limited to the intake port injection engine as shown in FIG. 1, but can be variously modified and applied to a direct injection engine.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an entire engine control system showing an embodiment (1) of the present invention.

FIG. 2 is a block diagram showing functions of an engine control system according to the embodiment (1).

FIG. 3 is a flowchart showing a processing flow of a required indicated torque calculation program according to the embodiment (1).

FIG. 4 is a flowchart showing a flow of processing of an engine control program according to the embodiment (1).

FIG. 5 is a diagram conceptually showing a map of air-fuel ratio-torque efficiency characteristics.

FIG. 6 is a diagram conceptually showing a map of an ignition retard amount-torque efficiency characteristic.

FIG. 7 is a time chart showing the behavior of the control in the case of the required indicated torque sudden decrease in the embodiment (1).

FIG. 8 is a time chart showing a control behavior in the case of a sudden change in the target air-fuel ratio according to the embodiment (1).

FIG. 9 is a block diagram showing functions of an engine control system according to the embodiment (2).

FIG. 10 is a flowchart showing the flow of processing of an engine control program according to the embodiment (2).

FIG. 11 is a time chart showing a control behavior in the case of a sudden change in the target air-fuel ratio according to the embodiment (2).

FIG. 12 is a block diagram showing functions of an engine control system according to the embodiment (3).

FIG. 13 is a flowchart showing the flow of processing of an engine control program according to the embodiment (3).

FIG. 14 is a time chart showing a control behavior in the case of a sudden change in the target air-fuel ratio according to the embodiment (3).

FIG. 15 is a block diagram showing functions of an engine control system according to the embodiment (4).

FIG. 16 is a flowchart showing the flow of processing of an engine control program according to the embodiment (4).

FIG. 17 is a time chart showing a control behavior in the case of a sudden change in the target air-fuel ratio according to the embodiment (4).

FIG. 18 is a block diagram showing functions of an engine control system according to the embodiment (5).

FIG. 19 is a flowchart (part 1) illustrating a flow of processing of an engine control program according to the embodiment (5).

FIG. 20 is a flowchart (part 2) showing the flow of processing of the engine control program of the embodiment (5).

FIG. 21 is a time chart showing a control behavior in the case of a sudden change in the target air-fuel ratio according to the embodiment (5).

FIG. 22 is a block diagram showing functions of an engine control system according to the embodiment (6).

FIG. 23 is a flowchart showing a flow of processing of a main part of the engine control program of the embodiment (6).

FIG. 24 is a time chart showing a control behavior in the case of a sudden change in the target air-fuel ratio according to the embodiment (6).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Engine (internal combustion engine), 12 ... Intake pipe, 14 ... Air flow meter, 15 ... Throttle valve, 18 ... Intake pressure sensor, 20 ... Fuel injection valve, 21 ... Exhaust pipe, 22 ...
Catalyst, 23: air-fuel ratio sensor, 25: crank angle sensor,
27 ... ECU, 51 ... Requested torque calculation means, 52 ...
Target air-fuel ratio setting means, 52a... Target air-fuel ratio setting means, 5
3 ... torque efficiency calculating means, 54 ... correction torque calculating means,
55 ... target air amount calculating means, 55a ... first target air amount calculating means, 56 ... target throttle opening degree calculating means, 57 ... throttle valve driving means, 58 ... cylinder air amount calculating means,
Reference numeral 59: target fuel amount calculation means, 60: basic ignition timing calculation means, 61: intake delay correction means, 62: estimated torque calculation means, 63: ignition delay amount calculation means, 64: ignition timing calculation means, 66: second Target air amount calculating means, 67: first ignition retard amount setting means, 68: torque efficiency calculating means, 69: total torque efficiency calculating means, 70: intake delay correcting means, 71: second ignition retard amount calculating means, 72: second target air-fuel ratio setting means; 73: ignition retard amount limiting means.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 11/10 F02D 11/10 F 43/00 301 43/00 301B 301H 301K F02P 5/15 F02P 5/15 BF term (reference) 3G022 DA02 EA01 EA06 FA06 GA05 GA06 GA08 GA11 3G065 AA04 CA26 DA05 DA06 DA15 EA07 EA10 FA12 GA00 GA01 GA05 GA09 GA10 GA26 GA27 GA33 GA41 GA46 HA06 HA21 HA22 JA04 JA09 JA11 KA02 3G084 AA03 BA03 BA04 EA11 EB04 EB12 EC01 EC03 FA00 FA01 FA02 FA07 FA10 FA11 FA20 FA29 FA33 FA38 3G301 HA01 HA06 JA08 JA11 KA06 KA23 LA03 LC03 MA11 NA06 NB03 NB13 NC02 ND02 NE01 NE06 NE14 NE21 PA01Z PA07Z PA09Z PA10Z PA11A02Z13 PD02

Claims (6)

[Claims] 1. A required indicated torque calculating means for calculating a required indicated torque to be generated by combustion of an internal combustion engine based on an accelerator opening or the like operated by a driver, and a target for setting a target air-fuel ratio according to operating conditions. Air-fuel ratio setting means; correction torque calculating means for correcting the required indicated torque by an amount corresponding to the influence of the target air-fuel ratio to obtain a correction torque; fuel based on the target air-fuel ratio and the amount of air flowing into the cylinder. Fuel injection amount calculating means for calculating an injection amount; target air amount calculating means for calculating the target air amount based on the correction torque; target throttle opening degree for calculating a target throttle opening based on the target air amount Computing means; intake delay correcting means for delay-correcting the target air amount by an amount equivalent to the delay of the intake system to obtain an estimated air amount; and calculating an estimated torque based on the estimated air amount. Estimated ignition angle calculating means for calculating an ignition retardation amount based on the estimated torque and the correction torque; and A control device for an internal combustion engine, comprising: ignition timing calculating means for obtaining a final ignition timing. 2. A demanded indicated torque calculating means for calculating a required indicated torque to be generated by combustion of an internal combustion engine based on an accelerator opening or the like operated by a driver, and a target for setting a target air-fuel ratio according to operating conditions. Air-fuel ratio setting means; fuel injection amount calculating means for calculating a fuel injection amount based on the target air-fuel ratio and the amount of air flowing into the cylinder; torque efficiency calculation for calculating torque efficiency according to the target air-fuel ratio Means, correction torque calculating means for correcting the required indicated torque with the torque efficiency to obtain a correction torque, target air amount calculation means for calculating a target air amount based on the correction torque, and a target air amount based on the target air amount. A target throttle opening calculating means for calculating a target throttle opening by using an intake delay compensation for obtaining an estimated torque efficiency by correcting the torque efficiency by a delay corresponding to a delay of the intake system. Means, an ignition retard amount calculating means for calculating an ignition retard amount based on the estimated torque efficiency and the torque efficiency, and a final ignition timing based on a basic ignition timing determined from an operation state and the ignition retard amount. A control device for an internal combustion engine, comprising: 3. A required indicated torque calculating means for calculating a required indicated torque to be generated by combustion of the internal combustion engine based on an accelerator opening or the like operated by a driver, and a target for setting a target air-fuel ratio according to operating conditions. Air-fuel ratio setting means; fuel injection amount calculating means for calculating a fuel injection amount based on the target air-fuel ratio and the amount of air flowing into the cylinder; correcting the required indicated torque by an amount corresponding to the influence of the target air-fuel ratio Correction torque calculating means for calculating a correction torque by calculating a target air amount based on the correction torque; and a target throttle opening degree calculating a target throttle opening degree based on the target air amount. Means, intake delay correction means for delay-correcting the target air amount by an amount equivalent to the delay of the intake system to obtain an estimated air amount, and a point based on the estimated air amount and the target air amount. An ignition retard amount calculating means for calculating a retard amount, and an ignition timing calculating means for obtaining a final ignition timing based on the basic ignition timing determined from an operation state and the ignition retard amount. Control device for internal combustion engine. 4. A required indicated torque calculating means for calculating a required indicated torque to be generated by combustion of the internal combustion engine based on an accelerator opening or the like operated by a driver, and a target for setting a target air-fuel ratio according to operating conditions. Air-fuel ratio setting means; fuel injection amount calculating means for calculating a fuel injection amount based on the target air-fuel ratio and the amount of air flowing into the cylinder; torque efficiency calculation for calculating torque efficiency according to the target air-fuel ratio Means; correction torque calculating means for correcting the required indicated torque with the torque efficiency to obtain a correction torque; first target air amount calculation means for calculating a first target air amount based on the correction torque; (1) target throttle opening calculating means for calculating a target throttle opening based on a target air amount; and estimating an estimated air amount by correcting the first target air amount with a delay corresponding to a delay of an intake system. Intake delay correcting means, second target air amount calculating means for calculating a second target air amount based on the required indicated torque, ignition based on the estimated air amount, the second target air amount, and the torque efficiency. An ignition retard amount calculating means for calculating a retard amount, and an ignition timing calculating means for obtaining a final ignition timing based on the basic ignition timing determined from an operation state and the ignition retard amount. Control device for internal combustion engine. 5. A required indicated torque calculating means for calculating a required indicated torque to be generated by combustion of the internal combustion engine based on an accelerator opening or the like operated by a driver, and a first target air-fuel ratio is set according to operating conditions. A first target air-fuel ratio setting unit that sets a first ignition retard amount in accordance with an operating condition; a first ignition retard amount setting unit that sets a first ignition retard amount in accordance with an operating condition; A total torque efficiency calculating means for calculating the total torque efficiency, a correction torque calculating means for correcting the required indicated torque with the total torque efficiency to obtain a correction torque, and calculating a first target air amount based on the correction torque. A first target air amount calculating means for calculating, a target throttle opening degree calculating means for calculating a target throttle opening based on the first target air amount, and a delay correction of the total torque efficiency by an amount corresponding to a delay of the intake system. Push Intake delay correction means for obtaining a total torque efficiency; second ignition delay amount calculation means for calculating a second ignition retard amount based on the estimated total torque efficiency and the total torque efficiency; basic ignition determined from an operation state Ignition timing calculating means for obtaining a final ignition timing based on the timing and the second ignition retard amount, and a second target air-fuel ratio for setting a second target air-fuel ratio based on the estimated total torque efficiency and the total torque efficiency A control device for an internal combustion engine, comprising: a setting unit; and a fuel injection amount calculating unit that calculates a fuel injection amount based on the second target air-fuel ratio and an amount of air flowing into a cylinder. 6. An ignition retard amount restricting means for restricting the second ignition retard amount to a predetermined limit value or less, wherein the second target air-fuel ratio setting means comprises a restriction amount of the second ignition retard amount. The control device for an internal combustion engine according to claim 5, wherein the second target air-fuel ratio is set in consideration of: