JP2000291467A - Control device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To control an engine speed to a target value without further deteriorating a poor combustion state after starting. A post-starting engine speed peak value actual value gnepk in an idling state and within a fixed time after starting is calculated, a post-starting engine speed peak value target value tnepk is read from a map, and a ratio rnepk thereof is obtained (step). 10
01 to 1005). If the ratio rnepk is out of the target range, it is considered that the combustion state is defective, so the flag xnedwn indicating the combustion state defect is turned ON (steps 1006 to 1007).
The next value (command value) of the intake amount is kept at the current value, that is, the change of the intake amount is prohibited (step 1008),
The next value (command value) of the ignition timing is changed to the current value by tnepk / gn
It is determined by multiplying by epk (step 1009).

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, and more particularly to a device after starting (in this specification, after starting, immediately after starting until a complete explosion of the engine reaches an idle steady state).
The present invention relates to a control device for controlling the number of revolutions to a target value.

[0002]

BACKGROUND OF THE INVENTION For a better atmospheric environment, automobiles are also being developed to make exhaust gas cleaner. Accordingly, improvement of exhaust gas after starting has become more and more important.In particular, since the number of revolutions after starting has a large effect on exhaust gas, the target value must be set so that the number of revolutions after starting does not vary. There is a strong demand for precise control to meet the requirements. By the way, the reason why the rotational speed after start-up varies is that a state of poor combustion occurs. Therefore, in order to prevent the rotation speed after the start from fluctuating, it is necessary to detect the combustion state after the start of the engine and control the combustion state to be good if the combustion state is poor. is there. As a device for controlling the combustion state to be good, for example, in the device described in JP-A-62-3139, the throttle opening is controlled to a target value corresponding to the temperature at the time of starting the internal combustion engine. I have.

[0003]

However, if the intake air amount is changed when the combustion state is poor, the combustion state may be further deteriorated. This is caused by poor combustion at start-up due to poor fuel atomization, fuel adhering to the wall of the intake port, etc., and insufficient fuel being introduced into the combustion chamber, resulting in a lean air-fuel ratio. However, when the throttle opening is controlled to be increased, the negative pressure in the intake pipe is reduced, so that the atomization of the fuel is further deteriorated and the air-fuel ratio becomes leaner. The present invention has been made in view of the above problems, and has as its object to provide a control device for an internal combustion engine that controls the engine speed to a target value without further deteriorating a poor combustion state after starting.

[0004]

According to the first aspect of the present invention, there is provided a control device for an internal combustion engine for controlling an engine speed to show a target change characteristic after starting, wherein a combustion state is determined. A combustion state determining means for controlling the engine speed to show a target change characteristic by changing an intake air amount;
Determining that the combustion state is good, comprising: a rotation speed control unit; and a second rotation speed control unit that changes a control value of another control parameter of the intake air amount to control the engine rotation speed so as to exhibit a target change characteristic. In this case, the first engine speed control means controls the engine speed to show the target change characteristic, and if it is determined that the combustion state is poor, the second engine speed control means controls the engine speed to the target change characteristic. A control device for an internal combustion engine adapted to perform control as shown in FIG. According to the control device for an internal combustion engine configured as described above, when it is determined that the combustion state is good, the intake air amount is changed so that the engine speed is controlled so as to show a target change characteristic,
When it is determined that the combustion state is poor, the control value of a control parameter other than the intake air amount is changed so that the engine speed is controlled so as to exhibit a target change characteristic.

According to the second aspect of the present invention, the first aspect is provided.
According to the invention, there is provided a control device for an internal combustion engine, wherein the second rotation speed control means changes at least one of an ignition timing, a fuel injection amount, and a fuel injection timing. According to the control device for an internal combustion engine configured as described above, when it is determined that the combustion state is good, the intake air amount is changed to control the engine speed to show the target change characteristic, and the combustion state is determined to be bad. In this case, at least one of the ignition timing, the fuel injection amount, and the fuel injection timing is changed so that the engine speed is controlled to show the target change characteristic.

According to the invention described in claim 3, according to claim 1
The invention further comprises a defective combustion state cylinder discriminating means for discriminating a cylinder having a defective combustion state, and when it is determined that the combustion state is defective, the cylinder having the defective combustion state is determined, and the cylinder having the defective combustion state is determined. There is provided a control device for an internal combustion engine in which two-speed control means controls the engine speed to show a target change characteristic. According to the control device configured as described above, when it is determined that the combustion state is poor, the cylinder having the combustion state failure is determined, and the cylinder having the combustion state failure is changed by changing control parameters other than the intake air amount to the engine. The rotation speed is controlled so as to show a target change characteristic.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 11 is a schematic diagram showing a hardware configuration common to each embodiment described later. In FIG.
An electronic control throttle 3 is provided in the intake passage 2 of the internal combustion engine 1 downstream of an air cleaner (not shown). The electronically controlled throttle 3 opens and closes a throttle valve 3a by a throttle motor 3b. When an opening command value is input from an ECU (engine control unit) 10, the throttle motor 3a changes the throttle value to this command value. In response, the throttle valve 3a is made to follow the command opening.

The opening of the throttle valve 3a is controlled from a fully closed state shown by a solid line to a fully opened state shown by a broken line. The opening is detected by the throttle opening sensor 4. The command opening is determined according to an accelerator pedal depression signal (accelerator opening signal) from an accelerator opening sensor 15 that is attached to the accelerator pedal 14 and detects an accelerator depression amount.

[0009] By the above electronic throttle valve 3,
Although it is sufficiently possible to control the intake air amount at the time of idling, as shown in this figure, an idle speed control valve (hereinafter, ISC) that bypasses the throttle valve 3a is used.
V) 5, it is also possible to control the intake air amount at the time of idling by the ISCV 5.

An atmospheric pressure sensor 18 is located upstream of the throttle valve 3 in the intake passage 2, and a surge tank 6 is located downstream. In the surge tank 6, a pressure sensor 7 for detecting the pressure of intake air is provided. Furthermore, surge tank 6
A fuel injection valve 8 for supplying pressurized fuel from a fuel supply system to an intake port is provided for each cylinder. Further, ignition is performed by causing an ignition coil 28 to generate a discharge at an ignition plug 29 based on a signal sent from the ECU 10 to an igniter 27.

A coolant temperature sensor 11 for detecting the temperature of the coolant is provided in the coolant passage 9 of the cylinder block of the internal combustion engine 1. The water temperature sensor 11 generates an analog voltage electric signal according to the temperature of the cooling water. The exhaust passage 12 contains three harmful components HC and C in the exhaust gas.
A three-way catalytic converter (not shown) for purifying O and NOx at the same time is provided. An O ₂ sensor 13 which is a kind of air-fuel ratio sensor is provided in an exhaust passage 12 on the upstream side of the catalytic converter. I have. The O ₂ sensor 13 generates an electric signal according to the concentration of the oxygen component in the exhaust gas. The signal of each sensor is input to the ECU 10.

The ECU 10 further includes a battery 16
Key position signal (accessory position, ON position, starter position) from ignition switch 17 connected to
Timing rotor 24 integrated with crankshaft timing pulley attached to one end of crankshaft
The top dead center signal TDC from the crank position sensor 21 provided in close proximity to the crank angle signal C for each predetermined angle
A, a reference position signal from the cam position sensor 30,
The temperature of the lubricating oil from the oil temperature sensor 22 is input. A ring gear 2 provided at the other end of the crankshaft
3 is rotated by a starter 19 when the engine 1 is started.

When the engine 1 starts operating, the EC 1
When U10 is energized, the program is started, the output from each sensor is taken in, and the throttle motor 3b that opens and closes the throttle valve 3a, the ISCV 5, the fuel injection valve 8, the igniter 27, and other actuators are controlled. To this end, the ECU 10 includes an A / D converter that converts analog signals from various sensors into digital signals, an input / output interface 101 through which input signals from various sensors and output signals for driving each actuator come and goes, and arithmetic processing. A CPU 102, a memory such as a ROM 103 and a RAM 104, a clock 105, and the like are provided, and these are interconnected by a bus 106.

Here, the detection of the rotational speed ne and the cylinder discrimination will be described. The timing rotor 24 is provided with signal teeth 25 at every 10 ° CA, but has two missing tooth portions 26 for detecting the top dead center, and has 34 teeth. The crank position sensor 21 includes an electromagnetic pickup,
A crank rotation signal for every 0 ° is output. The rotation speed Ne is obtained by measuring the interval (time) of the crank angle signal.

On the other hand, the cam position sensor 30 is attached to a camshaft that makes one rotation for every two rotations of the crankshaft, and generates a reference signal at the compression top dead center of the first cylinder, for example. The determination of a cylinder having a defective combustion state, which is performed in the first embodiment described later, is performed by measuring the elapsed time from a reference signal generated by the cam position sensor 30. Hereinafter, control of each embodiment of the present invention configured as described above will be described.

In each of the embodiments, the combustion state is determined based on whether or not the manner of change in the rotational speed is as desired.
If the target is not met, it is determined that the combustion state is defective, and control other than the intake air amount is performed so as to achieve the target. Therefore, first, the following three are considered as indices to be controlled as target indices, that is, controlled indices. Peak rotation speed after start Change rate of rotation speed after start Average increase rate of rotation speed after start

On the other hand, the following three control parameters are considered to make the above-mentioned controlled index equal to the target when the combustion state is defective. (a) Ignition timing (b) Fuel injection amount (c) Fuel injection timing

Therefore, the first embodiment: controlled index + control parameter (a) A first modification of the first embodiment: controlled index + control parameter (a) Second Modified Example: Controlled Index + Control Parameter (a) Second Embodiment: Controlled Index + Control Parameter (b) Third Embodiment: Controlled Index + Control Parameter (c) Fourth Embodiment Form: controlled index + control parameter (a) + cylinder determination will be sequentially described below.

<First Embodiment> This first embodiment learns (stores and updates) the peak rotational speed in a predetermined section after the engine starts, and responds to the learned value and the engine temperature. If the ratio of the predetermined target value (stored in the ECU 10) deviates from the target range, it is determined that a poor combustion condition has occurred, and after the next start, the ratio falls within the target range. Next, the current value of the ignition timing (command value) is corrected to be the next value, and the intake air amount (command value) is used as it is for the next value. At that time, the next value of the ignition timing is
The ignition timing of this time is multiplied by the ratio of the target value to the learned value of the peak rotational speed.

FIG. 1 is a flow chart for controlling the first embodiment. In step 1001, it is determined whether or not the engine is in an idle state. This is performed based on a signal from the throttle opening sensor 4 or the accelerator opening sensor 15. In step 1002, it is determined whether or not the time is within a predetermined time after the start, and this is performed by a timer that starts simultaneously with the start. If a negative determination is made in steps 1001 and 1002, nothing is performed and the process jumps to step 1010, and if both of the steps 1001 and 1002 are affirmatively determined, the process proceeds to step 1003, where the present peak rotational speed actual value after starting gnepk , And step 10
In step 04, a post-start peak rotational speed target value tnepk set according to the engine temperature is read from the map. Then, in step 1005, a ratio rnepk between the actual value gnepk after starting and the target value tnepk after starting obtained in step 1003, which is obtained in step 1003, rnepk = gnepk / tnep
Find k.

In step 1006, the actual peak speed after start gnepk and the target peak speed after start tnep
The ratio of k, rnepk = tnepk / gnepk is within the target range (KRNEPK2 to
(KRNEPK1) is determined, and if the determination is affirmative, the combustion state is considered to be good.
Jump to 010 and return. On the other hand, if a negative determination is made in step 1006, the combustion state is considered to be defective, so the routine proceeds to step 1007, where the flag xn indicating the defective combustion state is set.
Turn on edwn. Then, in step 1008, the next value (command value) of the intake air amount is kept at the current value, that is, the change of the intake air amount is prohibited, and in step 1009, the next value (command value) of the ignition timing is changed to the current value. Where rnepk = tnep
After multiplying by k / gnepk, the process proceeds to step 1010 and returns.

FIG. 2 is a diagram for explaining the determination of the combustion state according to the first embodiment. FIG. 2A shows the actual value of the peak rotational speed gnepk after the start due to the poor combustion state. The target value is much lower than the peak rotation speed target value tnepk, and the ratio rnepk =
This shows a case where tnepk / gnepk exceeds the upper limit value KRNEPK2 of the target range. On the other hand, FIG. 2B shows that the combustion state is good and the actual peak speed after start gnepk is substantially equal to the target peak speed after start tnepk, and the ratio rnepk = tnepk / g
nepk is within the target range.

In the first modified example of the first embodiment, as described above, when a combustion failure occurs after the current start, the intake air amount is made the same as the current value at the next start, and The ignition timing is changed to
No further deterioration of the combustion state due to the change of the intake air amount occurred,
Actual value of peak rotational speed after starting due to the effect of changing the ignition timing
Ratio of gnepk and target peak speed after start tnepk rnepk =
tnepk / gnepk falls within the target range.

<First Modification of First Embodiment> A first modification of the first embodiment is a modification of the rotation speed of each minute section in a predetermined section after starting. If this detection value is out of the predetermined target range, it is determined that a combustion failure state has occurred, and the rotation speed change of each minute section within the predetermined section after the next start is detected. The current value of the ignition timing (command value) is corrected to be the next value so that the rate falls within the target range, and the intake air amount (command value) is used as it is for the next value. However, the next value of the ignition timing is determined by adding a predetermined correction amount to the current ignition timing.

FIG. 3 is a flowchart for controlling the second modification of the first embodiment. Step 11
01 and 1102 correspond to step 100 in the first embodiment.
1 and 1002, and the description is omitted. In step 1103, the rotation speed change rate gdlne of each minute section is calculated. In step 1104, the rotation speed change rate gdlne of the minute section calculated in step 1103 is within the target range (KDLNE2 to KD).
LNE1), and if the determination is affirmative, the combustion state is considered to be good.
Jump to 11 and return. On the other hand, if a negative determination is made in step 1104, the combustion state is considered to be defective, so the routine proceeds to step 1105, where a flag xned indicating a defective combustion state is set.
Turn wn ON. Then, in step 1106, the next value (command value) of the intake air amount is kept at the current value, that is, the change of the intake air amount is prohibited.

In step 1107, the rotational speed change rate gdln
It is determined whether or not e exceeds the upper limit value.If the determination is affirmative, that is, if the upper limit value is exceeded, the rotational speed change rate gdlne after the current start is set to the target range upper limit value KD.
Step 1 because it is a jump above LNE2
At 108, the correction amount ΔIA is subtracted from the current ignition timing IAST to retard the rotation so that the rotation speed decreases, and then the process proceeds to step 1111 and returns.

On the other hand, if a negative determination is made in step 1107, the process proceeds to step 1109, where it is determined whether or not the rotational speed change rate gdlne is lower than the lower limit value KDLNE1 of the target range. What is affirmedly determined in step 1109 is that
The rotational speed change rate gdlne after this start is the lower limit of the target range.
Since it is below KDLNE1 and the number of revolutions drops sharply,
In step 1110, the correction amount ΔIA is added to the current ignition timing IAST to advance the rotation so that the rotation speed increases, and then the process proceeds to step 1111 and returns. It should be noted that since a negative determination in step 1109 cannot be realized, the process directly proceeds to step 1111 and returns.

FIG. 4 is a diagram for explaining the determination of the combustion state in the first modification of the first embodiment. FIG. 4A shows a drop in the number of revolutions after the start due to a poor combustion state. Occurs, and the rotational speed change rate gdlne falls to the lower limit value KDLN of the target range.
It shows the case where it falls below E1. On the other hand, FIG. 4B shows a case where the combustion state is good and the rotational speed change rate gdlne is within the target range.

In the first modified example of the first embodiment, as described above, when a combustion failure occurs after the current start, the intake air amount is made the same as the current value at the next start, and The ignition timing is changed to
No further deterioration of the combustion state due to the change of the intake air amount occurred,
Due to the effect of changing the ignition timing, the rotation speed change rate gd in a minute section
lne is within the target range. Note that, as in the first modification, the correction amount ΔIA is added to or subtracted from the current ignition timing IAST as in the first modification, even when the peak rotation speed is used as the controlled index as in the first embodiment. It is also possible to set the next ignition timing IAST.

<Second Modification of First Embodiment> A second modification of the first embodiment is a modification of the rotation speed of each minute section within a predetermined section after starting. Is learned (stored and updated), and if the ratio between the learned value and a predetermined target value (stored in the ECU 10) according to the engine temperature deviates from a predetermined target range, the combustion is started. It is determined that a defective state has occurred, and after the next start, the current value of the ignition timing (command value) is corrected to the next value so that this ratio falls within the target range, and the intake air amount (command value) is Is used as it is for the next value.

FIG. 5 is a flowchart for controlling the second embodiment. Steps 1201 to 120
3 is step 110 of the first modification of the first embodiment.
1 to 1103, and a description thereof will be omitted. In step 1204, the average value of the rotational speed change rate actual value gdlnes after the start
Calculate m. Here, the actual rotational speed change rate average value gdlnesm after starting is an average of the rotational speed change rates of each minute section in a predetermined section, but the average is not only a simple average, but is suitable for judgment. And various weighted averages. Next, in step 1205, the target value tdlnesm of the average rotational speed change rate after starting is read from the map, and in step 1206, the actual rotational speed change rate average value gd after start is read.
Calculate the ratio rdlnesm = tdlnesm / gdlnesm between lnesm and the target rotational speed change rate average value target value tdlnesm.

In step 1207, it is determined whether or not the ratio rdlnesm determined in step 1206 is within a predetermined target range (KRDLNESM2 to KRDLNESM1). Returning, if a positive determination is made, it means that the actual rotational speed change rate average value gdlnesm after start is significantly different from the target rotational speed change rate average target value tdlnesm, and combustion failure has occurred. Then, in step 1208, the flag xnedwn indicating the occurrence of combustion failure is turned ON, the next value (command value) of the intake air amount is kept at the current value in step 1209, and the next value of the ignition timing (step 1210) is maintained. Command value) to the current value, the ratio rdlnesm = tdlnesm
After multiplying by / gdlnesm, the process proceeds to step 1211 and returns. Note that the rotation speed change rate gdlne is calculated in the same minute section as in the first modification of the first embodiment, but it can be made coarse enough to prevent discrimination.

FIG. 6 is a diagram for explaining the determination of the combustion state in the second modification of the first embodiment. FIG. 6A shows a drop in the number of revolutions after the start due to a poor combustion state. As a result, as a result, the actual value gdlnesm of the rotational speed change rate average value after the next start and the target rotational speed change rate average value tdln
This shows a case where the ratio of esm rdlnesm = tdlnesm / gdlnesm exceeds the upper limit value KRDLNESM2 of the target range. on the other hand,
FIG. 6 (B) shows the ratio rdlnesm = td when the combustion condition is good.
This shows a case where lnesm / gdlnesm is within the target range.

In the second modified example of the first embodiment, as described above, when a combustion failure occurs after the current start, the intake air amount is made the same as the current value at the next start, and The ignition timing is changed to
No further deterioration of the combustion state due to the change of the intake air amount occurred,
Due to the effect of the change in the ignition timing, the actual value of the rotational speed change rate after start actual value gdlnesm and the target value of the rotational speed change rate average value after start tdln
The ratio of esm rdlnesm = tdlnesm / gdlnesm falls within the target range. It should be noted that, also in the second modification, as in the first modification, it is also possible to add or subtract the correction amount ΔIA from the current ignition timing IAST to obtain the next ignition timing IAST.

<Second Embodiment> This second embodiment learns (stores and updates) the peak rotation speed in a predetermined section after starting, and responds to the learned value and the engine temperature. If the ratio of the predetermined target value (stored in the ECU 10) deviates from the predetermined target range, it is determined that a poor combustion condition has occurred, and the ratio falls within the target range after the next start. Thus, the current value of the fuel injection amount (command value) is corrected to be the next value, and the intake amount (command value) is used as it is for the next value.

FIG. 7 is a flowchart for controlling the second embodiment. Steps 2001 to 2008 and 2010 of the flowchart are the same as steps 1001 to 1008 and 1010 of the first embodiment. Only in step 2009, the fuel injection amount is changed instead of the ignition timing. In step 2009,
The next value (command value) TAUST of the fuel injection amount is changed to the current value TAUS
It is determined by multiplying T by the ratio rnepk = tnepk / gnepk of the actual peak speed after start gnepk and the target peak speed after start tnepk.

In the second embodiment, as described above, when combustion failure occurs after the current start, the intake air amount is made the same as the current value at the next start, and the fuel injection amount is changed instead. As a result, after the next start, the deterioration of the combustion state does not occur due to the change in the intake air amount, and the actual value of the peak rotational speed after starting gnepk and the target value of the peak rotational speed after starting due to the effect of the change in the fuel injection amount. Ratio of tnepk rnepk = gnepk /
tnepk falls within the target range. In the second embodiment, the next value (command value) TAUST of the fuel injection amount is determined by multiplying the current value TAUST by the ratio rnepk = tnepk / gnepk. However, in the first embodiment, Tn as in the first modification of
The correction amount ΔTAU is added to or subtracted from the current fuel injection amount TAUST according to the value of epk / gnepk, and the next fuel injection amount TAUST is calculated.
It can be UST. In addition, as the controlled index, instead of the peak rotation speed, the post-start rotation speed change rate as in the first modification of the first embodiment, or the startup as in the second modification of the first embodiment. It is also possible to use the post-rotation speed change rate average value.

<Third Embodiment> This third embodiment learns (stores and updates) the peak number of revolutions in a predetermined section after the start, and responds according to the learned value and the engine temperature. If the ratio of the predetermined target value (stored in the ECU 10) deviates from the predetermined target range, it is determined that a poor combustion condition has occurred, and the ratio falls within the target range after the next start. Thus, the current value of the fuel injection timing (command value) is corrected to be the next value, and the intake air amount (command value) is used as it is for the next value.

FIG. 8 is a flowchart for controlling the third embodiment. Steps 3001 to 3008 and 3010 of the flowchart are the same as steps 1001 to 1008 and 1010 of the first embodiment. In step 3009, the fuel injection timing is changed instead of the ignition timing. In step 3009, the next value (command value) INJST of the fuel injection timing is set to the current value INJST and the actual engine speed peak value after the engine is started. gnepk
And the target engine speed peak value tnepk after start
Determined from the map based on the value of k.

FIG. 9 shows the above-mentioned map, in which the horizontal axis represents the ratio rnepk = tnepk / gnep of the actual engine speed peak value gnepk after start and the target engine speed peak value target value tnepk after start.
k, and the vertical axis is INJST, which specifically indicates the injection end timing. Asynchronous injection and synchronous injection are classified according to the value of rnepk = tnepk / gnepk. Asynchronous injection is injection before the intake valve is opened, synchronous injection is injection during the opening of the intake valve, Therefore, if asynchronous injection is performed during a cold start, fuel droplets accumulate on the back surface of the intake valve and cause combustion failure.On the other hand, if synchronous injection is performed during normal operation, the atomization time is shortened and combustion deteriorates. Become.

In the third embodiment, as described above, when a combustion failure occurs after the current start, the intake air amount is made the same as the current value at the next start, and the fuel injection timing is changed instead. As a result, after the next start, further deterioration of the combustion state due to the change of the intake air amount does not occur, and the actual peak rotational speed gnep
The ratio rnepk to the peak speed target value tnepk after the start of k
= tnepk / gnepk falls within the target range. Note that, as the controlled index, instead of the peak rotation speed, the rotation speed change rate after the start as in the first modification of the first embodiment or the start as in the second modification of the first embodiment is used. It is also possible to use the post-rotation speed change rate average value.

<Fourth Embodiment> In the fourth embodiment, the rate of change in the number of revolutions in each minute section within a predetermined section after starting is detected, and the detected value is determined in advance. If it is out of the target range, it is determined that a poor combustion state has occurred,
At the same time, the cylinder in which combustion failure has occurred is determined. The current value of the ignition timing (command value) of the cylinder in which the poor combustion state has occurred is set so that the rate of change in the rotational speed of each minute section within the predetermined section after the next start does not exceed (exceed) the determination value. The value is corrected and used as the next value, and the intake air amount (command value) is used as it is as the next value. Here, the reason for using each rate of change in each minute section as the controlled index is that the detection interval is shorter than the other peak speeds and the average value of the rate of change in speed, which is suitable for cylinder discrimination. Because.

FIG. 10 is a flowchart for controlling the fourth embodiment. In this flowchart, a cylinder discriminating step is inserted after step 1106 in the first modified example of the first embodiment. Steps 4009 and 4109 corresponding to steps 1108 and 1010 of the flowchart of the first modified example of the first embodiment.
At 011, the ignition timing is corrected only for the defective cylinder.

This cylinder discrimination is performed by measuring the time (angle) from the reference signal generated by the cam position sensor 30 based on the signal of the crank position sensor 21 as described above. In the fourth embodiment, as described above, when a combustion failure occurs after the current start, at the next start, the intake air amount is set to the same value as the current value, and the ignition timing is changed instead. As a result, after the next start,
No further deterioration of the combustion state due to the change of the intake air amount occurred,
Due to the effect of changing the ignition timing, the rotation speed change rate gd in a minute section
lne is set within the target range.At that time, the cylinder in which combustion failure occurred is identified, the ignition timing is changed only for that cylinder, and the ignition timing is changed for cylinders that do not need to change ignition timing. However, it is possible to prevent deterioration of exhaust gas and deterioration of drivability due to extra measures. Note that, instead of the ignition timing, the fuel injection amount as in the second embodiment and the fuel injection timing as in the third embodiment can be used as the control index. As in the first embodiment, it is also possible to multiply the current value by the ratio to obtain the next value.

[0045]

According to the invention described in each of the claims, after the start, the rotation of not only the single section but also the rotation of the predetermined section covering substantially the entire section up to the rising peak of the rotation speed before reaching the idling steady state. Since the combustion state is determined by comparing the number change characteristic with a predetermined determination value, it is possible to detect the rotation speed change due to poor combustion anywhere in the section.
In addition, it is possible to detect a defective combustion state early after the start of the engine, and to execute a countermeasure (correction) for eliminating the defective combustion state from an early stage based on the defective combustion state. It can contribute to the improvement of the atmospheric environment in a short period of time. In particular, according to the third aspect of the present invention, it is possible to identify a cylinder in which combustion failure has occurred, so that it is possible to take the minimum necessary countermeasure, and to reduce exhaust gas and drivability due to unnecessary countermeasures. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a flowchart of control according to a first embodiment.

FIGS. 2A and 2B are diagrams for explaining a combustion state determination in the control of the first embodiment. FIG.
(B) shows the case where the combustion state is good.

FIG. 3 is a flowchart of control according to a first modification of the first embodiment.

FIGS. 4A and 4B are diagrams illustrating determination of a combustion state in control according to a first modification of the first embodiment. FIG. 4A illustrates a case where the combustion state is poor, FIG. Is shown.

FIG. 5 is a flowchart of control according to a second modification of the first embodiment.

FIGS. 6A and 6B are diagrams illustrating determination of a combustion state in control according to a first modification of the first embodiment; FIG. 6A illustrates a case where the combustion state is poor; FIG. Is shown.

FIG. 7 is a flowchart of control according to the second embodiment.

FIG. 8 is a flowchart of control according to the third embodiment.

FIG. 9 is a diagram illustrating a change in injection timing in the control according to the third embodiment.

FIG. 10 is a flowchart of control according to a fourth embodiment.

FIG. 11 is a diagram schematically showing a hardware configuration common to the embodiments.

[Explanation of symbols]

 3: Electronic throttle 5: ISCV 10: ECU 21: Crank position sensor 30: Cam position sensor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 45/00 362 F02D 45/00 362E F02P 5/15 F02P 5/15 L (72) Inventor Hidemi Ohnaka Aichi No. 1 Toyota-cho, Toyota-shi, Toyota F-term in Toyota Motor Co., Ltd. (reference) KA36 3G084 AA03 BA03 BA05 BA06 BA13 BA15 CA01 CA02 CA03 DA04 DA23 DA28 EA11 EB11 EC02 EC03 FA33 FA34 FA36 FA38 FA39 3G301 HA01 HA06 JA03 JA04 JA21 KA01 KA05 KA07 LA00 LA03 LA04 LB02 LC03 MA01 MA11 MA18 NB01 NB02 NA06 NE01 NE06 NE16 NE17 NE23 PA07Z PA09Z PA11Z PD02A PD02Z PE01A PE01Z PE02Z PE03Z PE05Z PE08Z PF03Z PF16Z

Claims (3)

[Claims] 1. A control device for an internal combustion engine for controlling an engine speed to show a target change characteristic after starting, comprising: combustion state determining means for determining a combustion state; A first speed control means for controlling the engine speed to show a target change characteristic; and a second speed control for changing the control value of another control parameter of the intake air amount so as to control the engine speed to show the target change characteristic. Means for controlling the engine speed so as to show a target change characteristic by the first engine speed control means if it is determined that the combustion state is good, and the second means if it is determined that the combustion state is bad. A control device for an internal combustion engine, wherein the control device controls the engine speed to show a target change characteristic by a speed control means. 2. The control device for an internal combustion engine according to claim 1, wherein the second rotation speed control means changes at least one control value among an ignition timing, a fuel injection amount, and a fuel injection timing. . 3. A combustion state defective cylinder discriminating means for discriminating a cylinder having a defective combustion state, wherein when the combustion state is determined to be defective, the cylinder having the defective combustion state is determined, and the cylinder having the defective combustion state is determined. The control device for an internal combustion engine according to claim 1, wherein the second engine speed control means controls the engine speed so as to show a target change characteristic.