JPS61106976A - Control device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent a decrease of generated torque, worsening of fuel consumption and an increase of exhaust temperature, by providing a normalcy/ abnormality decision means, which decides detection of a combustion pressure vibration by a combustion pressure vibration detecting means, and an ignition timing correction quantity determining means which determines an ignition timing correction quantity. CONSTITUTION:An normalcy/abormality decision means B determines whether or not detection of a combustion pressure vibration by each combustion pressure vibration detecting means A, A' is normal. An ignition timing correction quantity determining means C, C' determines an ignition timing correction quantity on the basis of a detection result of the detecting means A, A' when a decision result of the decision means B is normal. While the determining means determines the ignition timing correction quantity on the basis of the ignition timing correction quantity of a cylinder or a cylinder group with the decision result normal when a decision result of the decision means B is abnormal. In this way, a decrease of generated torque, worsening of fuel consumption and an increase of exhaust temperature can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for an internal combustion engine, and particularly to an ignition timing control device.

[Prior Art J] Conventionally, an ignition timing control device that controls the ignition timing of an internal combustion engine is equipped with a plurality of cylinder pressure sensors that detect the cylinder pressure (combustion chamber pressure) of the engine, and detects the detection results of the cylinder pressure sensors. There is a system that corrects and controls the ignition timing for each cylinder so that the crank angle position at which the cylinder pressure of the engine is at its maximum reaches a predetermined target value based on (Japanese Patent Laid-Open No. 53-5642
(See Publication No. 9).

In other words, the crank angular position a pmax at which the cylinder pressure is maximum in an engine is a position slightly later than the compression-top dead center (Tr) (C), which differs depending on the engine, but is usually after the second dead center (Tr).
ATDC) is located at a position of 10° to 20°, and this crank angle position θpmax changes by changing the ignition timing.

1.1 Therefore, this crank angular position θpHaX is detected from the cylinder pressure at the m point, and the ignition timing is controlled according to this detection result, and the crank angular position fj pma
x is controlled to be a predetermined target value within ATDClo"° to 20"" to maximize the torque generated by the engine and improve fuel efficiency.

[The problem that the invention attempts to solve]

However, in such an internal combustion engine control device, the correspondence between a specific cylinder and a cylinder pressure sensor is uniquely fixed, and the ignition timing control for that specific cylinder is performed based on the detection of a single cylinder pressure sensor. It is designed to be based only on output.

Therefore, when an abnormality occurs such as destruction of the cylinder pressure sensor, wire breakage, or short circuit, the ignition timing of the cylinder whose ignition timing is controlled based on the output of the cylinder pressure sensor where the abnormality occurred will become inappropriate. .

For example, if the ignition timing is too retarded than the normal ignition timing, situations such as a decrease in generated torque, a decrease in fuel efficiency, or an excessive rise in exhaust temperature may occur, or if the ignition timing is too advanced than the normal ignition timing. As a result, situations such as occurrence of knocking, decrease in generated torque, and decrease in fuel efficiency occur. In particular, heavy knock caused by advancing the ignition timing too much can lead to engine destruction in the worst case scenario.

Means for Solving Problem r] This invention has been made to solve the above problem, and in the control device for an internal combustion engine according to the invention,
As shown in FIG. 1, a plurality of combustion pressure vibration detection means A, A' detect combustion pressure vibration of a plurality of cylinders or cylinder groups.
and each of these combustion pressure vibration detection means A, A'
The normality/abnormality determining means B determines whether the detection of combustion pressure vibration is normal or not.

When the determination result by the normality/abnormality determination means B is normal, the ignition timing correction amount determination means c and c' determine the ignition timing based on the detection results of the corresponding combustion pressure vibration detection means A and A'. Ignition timing correction amount determining means c for the cylinder or cylinder group for which the determination result is normal when the determination result of the normality/abnormality determination means B is abnormal;
', the ignition timing correction position is determined based on the ignition timing correction amount determined by c.

It should be noted that the functional block diagram shown in FIG. 1 merely shows an example when there are two combustion pressure vibration detection means, that is, two cylinders or two cylinder groups.

It is not limited to this.

[Effect]

When an abnormality occurs in the combustion pressure vibration detection means, the ignition timing of the cylinder or group of cylinders whose ignition timing was being controlled is changed according to the detection result of the combustion pressure vibration detection means to another whose combustion pressure vibration detection means is normal. By making the determination based on the ignition timing correction amount of the cylinder or cylinder group, inconveniences caused by abnormalities in the combustion pressure vibration detection means are suppressed.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 is an overall schematic diagram of a control system for a four-cylinder internal combustion engine that performs knock avoidance control according to the present invention.

In this internal combustion engine, air cleaner 1. The internal combustion engine 6 receives a mixture of air taken into the intake manifold 4 via the aphrometer 2 and the throttle valve 3 and fuel supplied by the injector 5.
and is ignited and combusted by the spark plug 7,
Exhaust gas generated by this combustion is discharged from the exhaust pipe via the catalytic converter 8 and the muffler S.

On the other hand, the control units 1 to 11 that are in charge of overall control include an intake air flow rate signal from an air flow meter 2, and a throttle switch 12 that detects the opening degree of the throttle valve B.
Throttle valve position signal from, crank angle sensor 1
3, a neutral signal from a neutral switch 15 that detects the neutral position of the transmission 14, and a vehicle speed signal from a vehicle speed sensor 16.

Also, a fuel temperature signal from the fuel temperature sensor 17 that detects the fuel temperature, an oxygen concentration signal from the 02 sensor 18 that detects the oxygen concentration in exhaust gas, and a water temperature sensor 1 that detects the cooling water temperature.
The water temperature signal from 9 is input.

Furthermore, an accelerator depression angle signal from an accelerator sensor 20 that detects the depression angle of the accelerator pedal is input.

Furthermore, a cylinder pressure signal from a cylinder pressure sensor 21 that detects the cylinder pressure (combustion chamber pressure) of each engine 6 is input.

Note that, hereinafter, each of the cylinder pressure sensors 21 of the first to fourth cylinders will be referred to as "cylinder pressure sensors 21^-21DJ."

The control unit 11 drives and controls the injector 5 to control the fuel supply amount based on these input signals and various data stored therein, and the ignition coil 22 supplies high voltage to the spark plug 7. Ignition is controlled by intermittent control of the primary current.

Note that the high voltage from the ignition coil 22 is distributed to the spark plugs 7 of each cylinder by a distributor (not shown). In addition, in the following explanation, the first
Spark plugs 7 of cylinders to 4th cylinder [spark plugs 7A to 7
It is called "D".

Further, the AAC valve 23 is driven and controlled to control the air flow rate bypassing the throttle valve 3 to control the idle rotation speed, and the VCM valve 24 is controlled to control the EGR valve 2.
5 to control the EGR amount.

In addition, in this figure 2, 26 is a fuel pump.

27 is a canister, 228 is a BC valve, and 29 is a check valve.

FIG. 3 is a block diagram showing the configuration of the control unit 11 in the control device for this internal combustion engine.

First, the cylinder pressure sensor 21A of the first cylinder is a piezoelectric conversion type pressure sensor, and is installed as a washer for the spark plug 7A installed in the cylinder head 6A as shown in FIGS. As described above, the charge signal Sll is outputted in accordance with the in-cylinder pressure (in-cylinder pressure) of the first cylinder.

In addition, the cylinder pressure sensors 21B of the other second to fourth cylinders
2.10 is also installed in the same way as the cylinder pressure sensor 21^, and outputs charge signals SI2 to S14 corresponding to the internal pressure of the second to fourth cylinders.

The charge amplifier 31A, for example, as shown in FIG.
Operator OP, resistor R, R2, capacitor C1,
After converting the charge signal S11 from the cylinder pressure sensor 21A into a voltage signal by a charge-voltage conversion circuit consisting of diodes D, D2, this voltage signal is sent to the operational amplifier OP I.
y 1a It is amplified by an amplifier circuit consisting of anti-Rz to R8 and a diode D3, and outputted as a detection signal S2+.

Note that the other charge amplifiers 31Tl to 310 are also configured in an interlude with the charge amplifier 31A, and receive charge signals S12 to S1 from the cylinder pressure sensors 21B to 210, respectively.
4 is converted into a voltage signal and then amplified to produce a detection signal S2゜~
Output as S24.

In other words, these cylinder pressure sensors 21A to 210 and charge amplifiers 31A to 31r) constitute a combustion pressure vibration detection sensor that constitutes the plurality of combustion pressure vibration detection means A in FIG.

In addition, the crank angle sensor 13 outputs a reference signal S2 at 70 degrees of compression - 1 - before dead center (T'(TI)C) of each cylinder, and the crank angle sensor 13 is positioned at every 1 degree (or 2 degrees) of the crank angle. Outputs signal S3.

Note that, of the reference signal S2, the reference signal corresponding to the first cylinder has a wider pulse width than the reference signals corresponding to the other cylinders.

Further, the position signal S3 may be output at other angles such as 0.1 degree, and the smaller the position signal is, the more the control accuracy is improved.

On the other hand, the control unit 11 is a circuit that also serves as the normality/abnormality determining means B and the ignition timing correction amount determining means C in FIG. 1, and includes multiplexers (MPX) 32. It consists of a signal processing circuit 33 and a main control circuit 34.

The multiplexer 32 includes charge amplifiers 31A to 31 that are input in response to a selection signal from the main control circuit 34.
n to (7) S, -s 24 is selected and output as the detection signal S2n.

The signal processing circuit 33, as shown in FIG.
a pass filter 33A, an amplifier circuit 331,
It consists of a rectifier circuit 33C and an integrator 33n, and performs a predetermined borrowing process on the detection signal S2n from the multiplexer 32 and outputs it as an integral signal S5.

In other words, the bandpass filter 33A receives the detection signals 821-82.1 from the charge amplifiers 31A-31r).
From the detection signal S2n from the multiplexer 32, which is any one of the Output as .

The amplifier circuit 3311 includes an operational amplifier o as shown in FIG.
p3. It consists of resistors R, o-R, 4, and a capacitor C2, and amplifies the detection signal S4 from the band pass filter 33A and outputs it as a detection signal S5.

The rectifier circuit 33G has an operational amplifier OP as shown in FIG.
4. It consists of resistors R15 to R18, a capacitor C3, and a diode D4rD6, and half-wave rectifies the detection signal S5 from the amplifier circuit 3311 and outputs it as a detection signal S6.

The integrator 33n has an operational amplifier as shown in FIG.
□Cth]9. Resistor R1, ~R22, capacitor C4
+ Integrating circuit consisting of Zener diode ZD and resistor R2
3 and a reset circuit consisting of a transistor Q1.

Then, timing is taken by a set/reset signal SSR from the main control circuit 34, which will be described later, which is input to the transistor Q1 of the reset circuit, and the detection signal S6 from the rectifier circuit 33C is integrated by the integrating circuit to produce an integral signal S7. Output as .

Note that this integrator 33D operates when the set/reset signal SSR from the main control circuit 34 is at a high level "H".
Transistor Q1 turns off and becomes integrable, and its set/reset signal SSR becomes 1. When ゛', transistor Ql turns on and capacitor c
Both ends of 4 are short-circuited and the integration is stopped.

Returning to FIG. 3, the main control circuit 34 includes CPU 35, R
T with built-in OM3G, RAM37, A/D converter, etc.
It consists of a microcomputer consisting of 1038 and a non-volatile memory (NVM) 39.

This main control circuit 34 receives a reference signal S2 and a position signal S3 from the crank angle sensor 13, and an integral signal S? from the signal processing circuit 33. etc.

Based on the reference signal S2 and position signal S3 from the crank angle sensor 13, the integrator 33 of the signal processing circuit 33
A set/reset signal SSR is output to D to control its integration operation.

Here, the main control circuit 34 starts the integration operation of the integrator 33D (7) at 40 degrees before compression top dead center (BTDC 40 degrees), and stops (-) the integration operation at compression second dead center (TDC). , compression" The integral operation is started again at 5° after the second dead center (ATDC), and is stopped at 45° ATDC.

Further, the main control circuit 34 makes a determination regarding knocking based on each of the input signals described above, and makes a determination regarding knocking,
Normal/abnormal determination of cylinder pressure detection by 1D and charge amplifiers 31A to 31n 1 Determination of correction amount of black spark timing 1 Processing related to ignition timing control such as determination of ignition timing, and based on the processing results, ignition device 40 power transistor 4
1 is turned on and off to control the ignition timing.

In addition, this ignition timing control (on/off control of the power transistor 41) is performed by setting a value (advanced angle value) corresponding to the determined ignition timing in an advance angle value (ADV) register (not shown) provided inside the T1038. Then, the values of these registers are compared with the value of the counter that counts the position signal s3, and when they match, the power transistor 41 is turned on or off.

In addition, in the ignition device 40, the power transistor 41 is controlled on and off, so that the primary current of the ignition coil 22, which is supplied with power from the battery 42, is interrupted and a high voltage is generated on its secondary side. High voltage is selectively distributed and applied to the spark plaques 7A to 7D of the first to fourth cylinders by the distributor 43 to generate spark discharge and ignite.

Note that this main control circuit 34 also performs control other than control related to one ignition timing, but a detailed explanation thereof will be omitted here.

Next, the operation of this embodiment configured as described above will be explained with reference to FIG. 8 and subsequent figures.

First, the knocking detection principle in this embodiment will be explained.

Generally, after the crank angle θpmax, the cylinder pressure vibration due to knocking appears and the cylinder pressure reaches its maximum.
” After two dead center (ATDC).

Therefore, when rectifying and integrating the detection results of in-cylinder pressure vibrations (combustion chamber pressure vibrations), the rectifying integral value after the dead center will be a value corresponding to the degree of knocking1, and the greater the degree of knocking, the larger the value. become. In other words, the rectified integral value after 1-dead center becomes a value related to the vibration energy at the time of knocking.

On the other hand, the rectified integral value before the - dead center is not affected by knocking, and if the engine speed and load are constant, it is not affected much by the ignition timing and becomes a substantially constant value. In other words,
The rectified integral value before the top dead center is a value related to the vibration energy during non-knocking.

In general, it is believed that the human auditory sense of knocking level is determined based on the relative strength difference between the sound pressure level due to constantly occurring background noise and the sound pressure level due to knocking vibration. It will be done.

Therefore, by taking the ratio or difference between the rectified integral value after top dead center and the rectified integral value before top dead center, and normalize the rectified integral value after top dead center with the rectified integral value before top dead center. , it is possible to detect knocking levels that match human sensory evaluation.

Next, the control of the integration operation of the integrator 33D of the signal processing circuit 33 by the main control circuit 34 for detecting knocking will be explained with reference to FIG. 8 (hereinafter referred to as "the figure"). do.

First, in a four-cylinder engine, the ignition of the first cylinder #l to the fourth cylinder #4 is controlled in the order of #1-#3-#4-$2-11.

At this time, the crank angle sensor 13 outputs the reference signal S2 at 70 degrees before the top dead center <rDc> of each cylinder as shown in FIG. The pulse width of S2 is wider than the reference signals for other cylinders.

Further, the crank angle sensor 13 outputs a position signal S3 at every crank angle of 1' (or 2 degrees), as shown in FIG.

On the other hand, when the cylinder pressure sensor 21A and charge amplifier 31A are normal, the charge amplifier 31A outputs the
A detection signal S21 as shown in c) is output, and the other charge amplifiers 31B-! Similar detection signal 82 from tld
Since the signals S2 to S24 are outputted, the multiplexer 32 outputs a detection signal S2n as shown in FIG.

As a result, the bandpass filter 33 of the signal processing circuit 33 receives the detection signal S2n from the multiplexer 32.
A extracts only the signal of a predetermined frequency and sends it to the amplifier circuit 33B.
When amplified in the same figure (
Detection as shown in (e) (n- No. S5 is output, and by half-wave rectifying it in the rectifier circuit 33C)
A detection signal S6 as shown in is input to the integrator 33D.

Therefore, the main control circuit 34 activates an internal counter to start counting the position signal S2 from the time when the reference signal S2 from the crank angle sensor 13 is detected.

Then, as shown in FIG.
Then, set/reset signal ssR is set to H” and integrator 3
The 3D integration operation is started, and at time t2 when TDC is reached, the set/reset signal SSR is set to "r-" to stop the integration operation.

Thereafter, the integrator 33T) similarly starts the integration operation at time t3 when ATDC reaches 5 degrees, and stops the integration operation at time t4 when ATDC reaches 45 degrees.

Thereby, the integral signal S? output from the integrator 33r)? For example, between time points tI and t4, the integral value is as shown in FIG. An integral value correlated to the vibration energy during knocking can be obtained by one operation of the integrator).

Note that the main control circuit 34 controls the integration operation of the integrator 33D at the same timing for the second to fourth cylinders, so the integral signal S7 output from the integrator 33rl as a whole is as shown in the figure (l. ).

Therefore, in a process not shown, the main control circuit 34 performs
The integrated signal s7 at each 1" DC is A/D converted, and this A/D converted value is stored at a predetermined address in the RAM 37 as a quantity B correlated to the vibration energy during non-knocking,
Further, the integrated signal S7 at each ATDC of 45° is A/D converted, and this A/D converted value is stored in a predetermined address of the M37 as an amount correlated to the vibration energy at the time of knocking.

Then, as will be described later, the ratio between this amount B and the amount (K/
Calculate B, l or the difference (KB) and reduce the quantity K to 11:
, incinerate.

Next, the principle of determining normality/abnormality of detection by the combustion pressure vibration detection means consisting of the cylinder pressure sensor 21 and the charge amplifier 31 will be explained.

Generally, the cylinder pressure Pa at the beginning of the compression stroke (for example, BTDC
When comparing the cylinder pressure (in-cylinder pressure at 60°) with the cylinder pressure Pb of the explosion stroke (for example, the cylinder pressure at 0° in ATDCl), the relationship P a < P b is always established.

Therefore, as shown in FIG. 8(d), the detection signal S2n from the multiplexer 32 that correlates with the cylinder pressure is A/D converted at a predetermined crank angle, for example, BTDC 60° and ATDCl 0° as described above. Cylinder pressure Pa, Pb
Correlation values (hereinafter referred to as [in-cylinder pressure correlation values Pa, PbJ
By comparing the in-cylinder pressure correlation values Pa and Pb, when Pa≧pb, it can be determined that an abnormality has occurred in the detection for the cylinder at that time.

Note that this determination method is for the case where the knocking level is detected by detecting the cylinder pressure. For example, when the knocking level is detected by detecting the vibration of the engine block,
This depends on another method, an example of which will be described later.

Furthermore, when the signal processing circuit is shared by each cylinder as in this embodiment, a separate determination means is required to determine whether the signal processing circuit itself is normal or abnormal. When provided for each cylinder, the signal processing circuit is also individually included in the combustion pressure vibration detection sensor, and a determination result including whether it is normal or abnormal can be obtained.

Next, the normality/abnormality determination and ignition timing correction amount determination processing executed by the main control circuit 34 will be described with reference to FIG. 9 and subsequent figures.

Referring to FIG. 9, cylinder discrimination processing is performed at 5TEP]. This is done by starting an internal counter to count the position signal S3 from the crank angle sensor 13 when the reference signal S2 from the crank angle sensor 13 is input (when it rises), and when the reference signal S2 falls. It is determined whether or not it is the first cylinder based on the count value when the cylinder is turned on, and other cylinders are determined based on the result of this determination.

In other words, as mentioned above, the first cylinder's "-70"' before dead center
The pulse width of the reference signal S2 output at 70° before the top dead center of the other cylinders is wider than that of the reference signal S2 output at 70° before the top dead center of the other cylinders. For example, the reference signal S for the first cylinder,! The pulse width of the reference signal S2 for the second to fourth cylinders is about 4° to 5°.

Therefore, by measuring the pulse width of the input reference signal S2, for example, the count value can be set to a predetermined value (for example, 10
If it is less than 'equivalent value)', it can be determined that the cylinder is the first cylinder, and since the reference signal S2 inputted thereafter is in the order of the third cylinder, the fourth cylinder, and the second cylinder, each cylinder is determined. be able to.

Then, in 5TIEP 2, a predetermined value is written in a predetermined register of T/(':+38, and the multiplexer 32 is switched and driven, and the charge amplifier 318 to 31r) is selected and outputted as a detection signal S2n.

After that, the signal processing circuit 3 as described above in 5TEP 3
Set the integration timing of the integrator 33I] of B
An integral operation of 133D is performed between TDC40° and TDC and between ATDC5'' and 45°.

Then, in accordance with the cylinder discrimination result in 5TIEP 1 in 5TEP 4 to 10, the knocking level detection is determined to be normal/abnormal and the ignition timing correction amount is determined. Perform quantity determination processing.

FIGS. 10 to 13 respectively show the first part in this FIG. 9.
FIG. 3 is a flowchart showing details of cylinder correction amount determination processing to fourth cylinder correction amount determination processing.

First, the meanings of abbreviations common to each figure (excluding those already explained) will be explained.

Fr, G: A 4-bit abnormal cylinder flag stored in the RAM 37 in advance, and the pin "b O" is the first cylinder.

Bit I-1) I is the second cylinder, bit b2 is the third cylinder.

Pill-b: 1, dC, which indicates whether the 4th cylinder is normal or abnormal.
: Ignition timing correction amount (1C1 is the first cylinder, dC
2 is the second cylinder, and dC3 is the third cylinder.

dc4 means each ignition timing correction amount for the fourth cylinder.

Note that if dc is positive, it represents an advance angle correction amount, and if it is negative, it represents a retard angle correction amount. Namely.

It is assumed that the larger the amount of correction, the more advanced the ignition timing is.

Min (dci): The most retarded ignition timing correction amount among the ignition timing correction amounts for other cylinders other than the relevant cylinder (for example, if it is the 1st cylinder, the other 2nd to 4th cylinders) means.

Next, the first cylinder correction amount determination process will be explained with reference to FIG. 10.

In this case, the multiplexer 32 selects the detection signal S2+ from the charge amplifier 31A through the process of 5TEP 2 described above, and inputs it as the detection signal 5211 to the signal processing circuit 33.

Therefore, in 5TEP11, the detection signal 82 n (S2
+) to BTDC60", ATT') CIOo to A/r)
Convert to cylinder pressure correlation value Pa, cylinder pressure correlation value 1) l)
Then, the rectified and integrated output S7 of the detection signal S2n in a predetermined angle range is converted by TDC (A/I) to obtain IR.

Then, in 5TEP12, the in-cylinder pressure correlation value Pa and the in-cylinder pressure correlation value Pb are compared, and it is checked whether Pb>Pa or not, and it is determined whether or not it is normal.

At this time, if P b > P a, that is, the first
If the combustion pressure vibration sensor of the cylinder is normal, the flag FL
The lowest bit 1-hO indicating whether the first cylinder of G is normal/abnormal is set to "0".

In other words, the read flag FLG (pit h b 3-1)
o) and rllllOJ (FT,,G・11
10), the bit l-bo is set to "0", and this result is stored in the RAM 37 as a flag FLG.

Then, at S1'EP 14, the rectified and integrated output S7 of the detection signal 82n (S2+) from the multiplexer 32 in a predetermined angular range is A/D-converted at 45° (ATI) to 1
Find tK.

Thereafter, in step 5TIEP] 5, a process is performed to calculate the correction lit d c of the ignition timing of the first cylinder.

Then, it is determined whether the learning condition is satisfied by 5TIEI) + 6, and if the learning condition is satisfied, 5
After learning the ignition timing correction amount dcI in TEP I 7, set the ignition timing correction amount dcl to dc1=o in STT Mi P18.
Make it.

The state in which the learning conditions for 5TrjP16 are satisfied refers to a steady operating state, that is, a state in which the operating state S during and immediately after acceleration/deceleration (transient operating state) or when the engine is not cold.

Specifically, the transient driving state is determined by A/D converting the accelerator depression angle detection signal of the accelerator sensor 20 (see Fig. 2), for example. i#: This can be done by checking whether the change M2 per hour of accelerator data +J is larger than a predetermined value.

Note that the determination can also be made based on the detection result of the intake air amount or the detection result of the engine load state such as the throttle valve opening or the negative pressure in the intake pipe.

Further, it can be determined whether the two engines are cold by comparing the detected water temperature value obtained based on the detection signal from the water temperature sensor 9 (see FIG. 2) with a predetermined set value.

Furthermore, in the learning process of the ignition timing correction amount dcI of 5TEP 17, the ignition timing correction 84 ．． ,
The quantity del is updated and recorded as a learning value.

Note that in this case, the actual engine speed and engine load determine the grid points of the learning table (engine speed, engine load, and -.
If the ignition timing correction amount is not found, the value obtained by weighting (interpolation) according to the slippage of the ignition timing is updated and recorded at the approximate grid point.
h) If Pa is not present, that is, when an abnormality occurs in the combustion pressure vibration sensor of the first cylinder, 5TIEP
]9, set b6 to ``1'' on the flag FL G's side 1.

In other words, the read flag FLG (pips 1 to b3 to +r
By taking the logical sum (FLG 100013) of the flags FI-, G and R,
Store in AM37.

After that, at 5TEP20, the flag FLG is set to N I I I
J is checked to determine whether the combustion pressure vibration sensors for all cylinders are abnormal.

At this time, if the flags FT and G are not rl l l IJ, that is, if the combustion pressure vibration sensor of one or more cylinders is normal, the most retarded ignition timing among the normal cylinders is corrected in ST'EP21. The amount Min(dci) is determined as the ignition timing correction amount dc+ for the first cylinder (dcl
←Min (dc i)).

In other words, when an abnormality occurs in the combustion pressure vibration sensor, the ignition timing for that cylinder is changed to the cylinder in which knocking is least likely to occur among the other cylinders with normal combustion pressure vibration sensors, that is, the cylinder whose ignition is delayed the most. Adjust to the amount of time correction.

Then, if the learning conditions are satisfied by proceeding to 5TEPI6 mentioned above, the learning value D will be added to the learning table in 5TEP17.
1, and set the ignition timing correction amount dc1 to "0" in 5TEP18.

On the other hand, in 5TFP20, the flag FI-G is [1
111J, that is, if the combustion pressure vibration sensors of all cylinders are abnormal, the ignition timing correction amount d of the first cylinder
Set c1 to "0" (dcI←0).

That is, at this time, control is performed to the basic ignition timing, which is set with sufficient margin for the knock limit.

Note that the second cylinder correction amount determination process to the fourth cylinder correction amount determination process are basically the same as this first cylinder correction amount determination process, and the flag FLG when the combustion pressure vibration sensor is iE normal/abnormal. Since the only difference is the rOJ or "]" bit, each 5TE of the first cylinder correction amount determination process
5 TIEP numbers in the 30s to 40s, 50s to 60s, and 70s to 80s are assigned to PII to 19, and their explanations will be omitted.

Furthermore, the sum of the ignition timing correction amount obtained in this manner and the learned value of the ignition timing correction amount is referred to as one ignition timing correction amount.

Next, the ignition timing correction amount calculation process during normal conditions in FIGS. 10 to 13 (STEPI 5.35.55°75)
The details will be explained with reference to FIG.

First, the meaning of each abbreviation in the figure (excluding those already explained) will be explained.

s r-: A reference value for determining the presence or absence of knocking.

KFl, , G: Flags used to determine the presence or absence of knocking.

BCNT': Value indicating the number of ignitions since the flag KFLG was reset (hereinafter referred to as [count value BCNTJ
) KCNT : Value indicating the number of ignitions since the flag KFI-G was set (hereinafter referred to as [count value KCNT
Note that KFLG, KCNT, and BCNT' are individually provided for each cylinder for each correction amount determination process.

First, calculate the ratio (K/B value) between the amount B that is the vibration energy correlation value during non-knocking and the amount that is the vibration energy correlation value during knocking described in 5TEP91, and then calculate the amount based on the amount B. /B calculation processing is performed to normalize I(.

Note that instead of calculating the ratio between the amount B and the amount, the difference (KB) between the amount B and the amount can be calculated and normalized.

Then, the 5THP92 compares the K/B value calculated by the above-described process with the reference value SL to determine whether the K/B value>SL, thereby determining whether knocking has occurred.

Here, the reference value SL will be explained.

First, the frequency distribution of /B values for various knocking phenomena in a 6-cylinder engine is shown, for example, in Figure 15, with a solid line for non-knocking and a two-dot chain line for trace knocking. Time is indicated by a dashed line, and medium knock is indicated by a dashed line.

Note that this distribution of the frequency of the /B value is the result of an experiment by the applicant, but it is considered to be common to most engines.

Therefore, basically the standard value SL is set to 5L=1.1, for example.
to determine whether there is knocking.

By the way, when the engine speed is in a high rotation range, human sensory evaluation is lowered due to the influence of mechanical vibrations of the engine itself, so the permissible knocking range becomes wider.

Therefore, for example, by changing the reference value sr- according to the engine speed, highly efficient operation can be realized. It should be noted that the reference value SL may be a fixed value (not limited to the negative value).

Returning to FIG. 14, if the /B value > SL in 5TEP92, that is, if knock has occurred, the 5T
Moving on to EP 103.

On the other hand, if the K/B value is not > SL, that is, /B value ≦ Sl-, and knocking has not occurred, 5TEI" 104, which will be described later in 5TEP93, is set when knocking occurs ( [set to 1] flag K
Determine whether FLG is [0].

At this time, if the flag KFLG is "0", that is, if knocking has not occurred, 5TEP94~9
When the state of /B value≦SL continues for 20 cycles or more after knocking occurs in step 7, the ignition timing is advanced by one degree.

That is, after the count value BCNT is incremented (+I) in 5TEP94, it is determined in 5TEP95 whether or not the count value BCNT exceeds [20J (BCNT>20).

At this time, if BCNT>20, the process ends; if BCNT>20, S 1' E P-
32 = 96 to increment the ignition timing correction amount dc from 1 to f+]
) After advancing the ignition timing by 1 degree, 5TEI”97
Clears BCNT (BCNT=0) for the first through first lines and ends the process.

On the other hand, if knock KFLG is not [0], that is, if knocking has occurred in the past, 5T
When the state of K/B value≦ST continues for 20 cycles or more after the /B value becomes >sr- in EP98 to EP102, a process is performed to make it non-knock.

In other words, after the count value KCNT was incremented to 1 (+1) at 5TEP98, the count value KCNT exceeded "20" at 5TEI'99 (KCNT>20).
Determine whether or not.

At this time, if KCNT>20, the process ends, and if KCNT>20, 5TEP 10
After resetting the flag KFLG with 0.

5TOP Clear count value KCNT with 101 (KC
NT=0) 5TIEPI 02 and count value B
Clear CNT and end the process.

On the other hand, when 5TEP92 becomes /[3 value>S14, that is, when a knock occurs, 5TE
At P103, it is checked whether the knock K F t-G is rQl to determine whether or not knocking has occurred for the first time.

At this time, if the flag KFLG is "0", that is, if it is the first knocking, then 5TEP I 04
After setting the flag KFLG (KFLG=1), 5
At TEP 1.05, the count value KCNT is cleared and the process ends.

On the other hand, if knock KFLG is not "0", that is, if knocking occurs for the second time or later,
5TEP 106 and the number of past ignitions is within 10 (KC
NT≦10), i.e. within 10 cycles/
It is determined whether the B value>SL.

At this time, if KCNT≦10, the above-mentioned 5TE
Execute P105 to end the process, and then execute KC! , lI
If N T≦lO, 5TEP l 0
Decrement (-1) L of the ignition timing correction amount dC at 7.
After retarding the ignition timing by 1 degree, the above-mentioned S'l'rE
Execute P I 05 and end the process.

Note that when /B value>SI is reached within 10 cycles, that is, when a knock occurs within 10 cycles after the knock occurs.

The reason why the ignition timing is retarded is that when the cumulative frequency is calculated from the above-mentioned Fig. 15, when SI is 1.1, the /B value changes at a rate of 10/+00 at the time of trace knock.
[, so the probability is 100/10 = IO1, that is, once in 10 times this condition (K / B value > S
It is based on the fact that L) will occur.

Similarly, in the case of a light knock, this value is Io
O/33=3 (times), I for medium knock
By setting 00/67=1.5 (times), the engine can be controlled to a desired knock level. This was confirmed through experiments conducted by the applicant.

In this manner, when knocking occurs, the frequency of occurrence of knocking is determined, and the amount of correction of the ignition timing is determined based on the result of this frequency determination.

In addition, the amount of correction d in each of the above 5 TIEPs 96 and 107
Regarding c, the ignition timing is advanced or retarded by more than a predetermined value by determining whether the correction amount dc after correction does not exceed a predetermined value and limiting the value of the correction amount dc. You can also choose not to.

Furthermore, the amount of retardation to be decremented in 07 is not limited to 1 degree, such as 1/2 degree or 1/4 degree, but also depends on the magnitude of the /B value, that is, the intensity or degree of knock. It can also be converted into a value.

Next, one ignition timing determination process will be explained with reference to FIG. 16.

This ignition timing determination process may be performed using, for example, the crank angle sensor 1!
When the reference signal S2 from 1 is input, it is entered and starts execution.

Then, at 5TEPI 11, the basic ignition timing is determined according to the intake air amount, engine speed, etc. Note that this is performed by looking up the characteristic values stored in the RoM 36, for example, in a table as shown in FIG.

Then, it is determined by 5TEPI 12 whether or not the cylinder for which the ignition timing is set is the first cylinder.

At this time, if it is the first cylinder, it is checked at 5TEP 11.3 whether or not the flag FLG is rFLG=11111 to determine whether or not the detection of the knocking level is abnormal for the gold cylinder.

And rFLG=1. l l If it is not IJ, that is, if the knocking level detection for at least one cylinder is normal, the learning table for the abnormal cylinder is corrected to the value for the normal cylinder (see 5 in Figures 10 to 13).
TFP21.41.61.81), so 5TEP114
The learning value D1 of the first cylinder learning table is read out by table lookup using the engine speed and engine load as parameters.

After that, -(70(D+DI+dc1)) is calculated based on the basic ignition timing, the learned value, and the correction amount del (ignition timing correction amount) at 5TIEP]15,
BTDC (D+DI + d el ) is converted into an angle from the input timing of the reference signal S2.

On the other hand, 5TEPI ] 3 and rFLG=II]
1", that is, if there is an abnormal knocking level detection for the gold cylinder, set the learning value D1 of the first cylinder learning table to rD, = OJ in 5TIEP116, and then set the 5TIEPI l 5 described in -. Execute.

In this case, the ignition timing correction amount dc1 for the first cylinder is
Since rdcl=OJ is set in 5TEP18 in the figure, the ignition timing correction amount (DI + del) becomes "0",
The basic ignition timing is the ignition timing.

Note that the reason why the learning value DI=0 is not written in the learning table is to make use of the learning table before the failure when the detected abnormal knocking level is restored to a normal state by repair or the like.

Also, if it is not the first cylinder at 5THpH2, 5TIE
Determine whether it is the 2nd cylinder at P117, and if it is the 2nd cylinder, 5TEPI 118~+21 is 5TEPI 13~116
Perform the same process as above, and if it is not the 2nd cylinder, STI'1
P122 determines whether it is the 3rd cylinder or not, and if it is the 3rd cylinder, 5TEP 123-126 5TrEI'l13-1
16, and if it is not the 3rd cylinder (4th cylinder
If it is a cylinder) 5TEPI 27-130 is 5TEP
Processing similar to II3 to II116 is performed to determine the ignition timing of each cylinder.

When the determination of the ignition timing for the cylinder is completed in this way, the determined ignition timing is set in the ADV register at 5TEr'+31.

As a result, ignition is performed at the determined ignition timing as described above.

In this way, in this internal combustion engine control device, when an abnormality occurs in the combustion pressure vibration detection sensor, the ignition timing correction amount of the cylinder corresponding to the combustion pressure vibration detection sensor where the abnormality has occurred is determined by the combustion pressure vibration detection sensor. is determined based on the ignition timing correction amount of other cylinders that are normal.

As a result, even if an abnormality occurs in the detection of the hook level for some cylinders, it is possible to suppress disadvantages such as a decrease in generated torque, a decrease in fuel efficiency, an increase in the exhaust temperature, and the occurrence of knocking.

In this case, knocking can be prevented by matching the ignition timing correction amount of the abnormal cylinder to the ignition timing correction amount of the cylinder whose ignition timing correction amount is the most retarded among the other normal cylinders, as in the above embodiment. It is possible to minimize the reduction in generated torque, decrease in fuel efficiency, increase in exhaust temperature, etc. while suppressing the occurrence of such problems.

In addition, when an abnormality occurs in all cylinders as in the above embodiment, by controlling the basic ignition timing, which is set to the retarded side with a margin to the knock limit, the occurrence of knocking can be suppressed and the occurrence of knocking can be suppressed. It is possible to suppress a decrease in torque, a decrease in fuel efficiency, a rise in exhaust temperature, etc.

Furthermore, by storing the learning table in a non-volatile memory as in the above embodiment, it becomes possible to set the appropriate ignition timing before the failure when normality is restored by repair or the like.

In the above embodiment, the ignition timing correction amount of the abnormal cylinder is calculated by combining the ignition timing correction amount of the ignition timing correction amount of the normal cylinder with the self (
However, the ignition timing correction amount for the normal cylinder (the learned value for the ignition timing correction amount) may be used as it is as the ignition timing correction amount for the abnormal cylinder.

Furthermore, in the above embodiment, the ignition timing correction -1 is learned, and the sum of the learned value and the ignition timing correction amount is used as the ignition timing correction amount, but the ignition timing correction -1 may not be learned. In this case, the ignition timing correction amount becomes the ignition timing correction amount as is.

However, by learning the amount of ignition timing correction, past history is utilized in the current control, making it possible to prevent knocking, or in other words, to reduce the frequency of knocking occurrences.

Furthermore, the knocking level can also be detected by detecting the vibration of the engine block as described above, instead of directly detecting the cylinder pressure vibration as in the embodiment described above.

The normality/abnormality determination process for knocking level detection in this case will be explained with reference to FIG. 18.

First, the level of knocking has a characteristic that it increases as the ignition timing advances, so as shown in Figure 19, the upper limit value KI + lower limit value KO of the knock level variation corresponding to the ignition timing is calculated as normal/abnormal knock level detection. The reference values for determination are determined in Table 2 and stored in the ROM in advance.

After detecting the knock level K, the knock level reference value table is looked up and the reference value K corresponding to the current ignition timing is determined. .

Read K1 and set it as the knock level and reference value K. .

A comparative judgment with K1 is made.

At this time, if the determination result is KO3≦1, the knock level detection is determined to be normal, and K<KO or K
) If K1, the knock level detection is determined to be abnormal.

Note that the judgment result K > K + occurs when the abnormality is caused by noise other than knocking.
FIG. 0 is a block diagram of main parts showing another embodiment of the present invention.

In this embodiment, θpmax is determined based on the crank angle θpmax when the cylinder pressure reaches the maximum.
! l The so-called M control corrects the ignition timing so that it matches the predetermined crank angle OH that maximizes the raw torque.
This is an embodiment in which B"I' control is performed.

Therefore, in this embodiment, the knocking level detection signal processing circuit 'N433 in FIG.
Instead, a signal processing circuit 45 for detecting the crank angle opmax is provided. Other points are Procra 11
Since the only difference is the processing, the same reference numerals as in FIG. 3 are given and the explanation thereof will be omitted.

The signal processing circuit 45 resets the main control unit 34]
・Signal SR, reference signal Ref (reference signal S 2 ) *
The timing is controlled by 'l' - position angle signal (pi signal) I'''O3<position signal S3
Detecting the crank angle θpmax when the cylinder pressure reaches the maximum value based on the detection signal S2n selected in step 2,
This circuit outputs the crank angle detection signal Sp to the main control section 34, and is configured as shown in FIG. 21, for example.

In this signal processing circuit '45, a low pass filter 4
5A is the detection signal S2 selected by the multiplexer 32
Vibration and noise caused by knocking are removed from n, frequency components of 1 to 2 K II z are extracted, and the extracted signal is output as a detection signal S8.

The peak hold circuit 45B is connected to 1103 of the main control unit 34.
8, the peak value of the detection signal S8 output from the low-pass filter 45A, that is, the time when the cylinder pressure reaches the maximum, is detected, and at that time, the peak value detection signal Spp is output. do.

The angle detection counter 45C is set to T1038 of the main control unit 34.
The same <
Counting of the lit punctuation signal PO8 from T1038 is started.

The angle detection counter 45C then stops counting in response to the peak value detection signal SPP from the peak hold circuit 45B.

Therefore, the crank angle θpiax is obtained by the main control unit 34 reading the count value (crank angle signal Sp) of the angle detection counter 45C at this time.

Next, the normality/abnormality determination and ignition timing correction amount determination processing in this embodiment will be explained with reference to FIGS. 22 to 26.

First, the 5TEP] 5 ] to 160 processing shown in FIG. 22 is performed to the ST[EP 1 to 10
Similarly to the process described above, the cylinder for which the ignition timing correction amount is to be determined is determined, and the ignition timing correction amount determination process is performed.

However, 5TEP l corresponding to 5TEP 3 in Figure 9
The process at step 53 does not set the integration timing, but instead sets the timing for detecting the crank angle θpmax as described in 1-1.

Next, 5TEPI 55. in this Figure 22. 15
7. First cylinder correction amount determination process at 159 and 160 ~
The fourth cylinder correction amount determination process will be explained with reference to FIGS. 23 to 26. These processes are shown in Figures 10 to 1.
Since this process is basically the same as each process shown in FIG. 3, it will be explained in detail.

First, among the abbreviations in each figure, fb is ignition timing correction acid, fb is the first cylinder, fb2 is the second cylinder, fb,
3rd cylinder 1fb4 means each ignition timing correction amount of the 4th cylinder.

Further, Σ(fbi): means the average value of each ignition timing correction amount (ignition timing correction planner learned value) of other normal cylinders other than the cylinder concerned.

Note that this Σ(f b i) is calculated by (average value of each ignition timing of normal cylinders) and (basic ignition timing + learned value D of the relevant cylinder)
+) may be used as the difference. In other words, it may be determined based on the ignition timing of other normal cylinders.

Next, the first cylinder correction amount determination process will be explained with reference to FIG. 23.

In this case, the MBT control is carried out in the same way as the above-mentioned knock avoidance control.

Since the crank angle θpmax is detected by detecting the cylinder pressure, the difference 1:() of the combustion pressure vibration sensor can be determined in the same manner as in the above embodiment.

Therefore, in 5TEPI 61, the cylinder pressure correlation value Pa and cylinder pressure correlation value pb are calculated, and in 5TEPI 62, the cylinder pressure correlation value Pa is compared with the cylinder pressure correlation value Pb, etc., and P b
> Check whether P a or not to determine whether it is normal or abnormal.

At this time, if P b > P a, that is, the first
If the cylinder combustion pressure vibration sensor is normal, 5TEP1
At step 63, the lowest bits 1 to bo of the flag FLG indicating whether the cylinder is normal or abnormal are set to 0.

Then, at STl'jI'' 164, the signal processing circuit 45
Read the crank angle detection signal Sp from , take in the crank angle 0pIlax, and take in the crank angle 0pIlax, 5THI) ] 6 E, set the ignition timing correction amount [b, of the first cylinder] to the detected crank angle Op Ill a X and the predetermined target crank angle. Calculation processing is performed according to the deviation from OM.

Then, it is determined whether the learning condition is satisfied at 5TrEP + 66, and if the learning condition is satisfied.

After learning the ignition timing correction if b in 5TPPI G 7, change the ignition timing correction amount fbt in S1'EP I 68.
fb.

: Set to 0.

For two, P b > P with 5TFP I 62
When an abnormality occurs in the combustion pressure vibration sensor of the J port f, that is, the first cylinder, the flag F1 and the G pitch l-ho are set to rtJ in 5TEP]69.

After that, at 5TEPI 70, the flag Fr-G becomes "11".
11" to determine whether the combustion pressure vibration sensors for all cylinders are abnormal.

At this time, if the flag FLG is not rl1]IJ and the combustion pressure vibration sensor of one or more cylinders is normal, the average value Σ(f b i) is determined as the ignition timing correction amount fbl of the first cylinder, and if the learning condition is satisfied by proceeding to the above-mentioned 5TEI' 1.66, S, TEP I
At 67, the learned value DI is updated and recorded in the learning table, and at 5TEP 168, the ignition timing correction amount fb is set to "0".

On the other hand, at 5TIEP I 70, the flag F[, G
is Ni1N and the combustion pressure vibration detection sensors of all cylinders are abnormal, the ignition timing correction amount fbl of the first cylinder is set to "0" (fb,←0).

The second cylinder correction amount determination process to the fourth cylinder correction amount determination process are basically the same as the first cylinder correction amount determination process, and the flag F L is set when the combustion pressure vibration sensor is normal/abnormal. Since the only difference is the bit to set G to "0" or rlJ, each 5T in the first cylinder correction amount determination process
EP 161-172 = 48 corresponds to 180-190 series, 200-210 series, 2
Each of the 5 TEP numbers in the 20-230 range will be assigned and their explanation will be omitted.

Note that the ignition timing determination process in this embodiment is performed in the first
Similar to the processing of the above embodiment shown in Fig. 6 (dcl to de
l is changed to f b, - f b4), so the explanation thereof will be omitted.

Next, still another embodiment of the present invention, that is, an embodiment in which MBT control is added to the above-mentioned knock avoidance control, will be described with reference to FIGS. 27 and subsequent figures.

First, the control unit in this embodiment can be constructed by adding the signal processing circuit 45 in FIG. 20 to the control unit in FIG. 3, except for program processing.

The control unit also controls the crank angle θpia
If x is determined by program processing, the detection signal S2n from the multiplexer 32 may be inputted to I10!18 in FIG. 3 after removing high frequency components. This example will be explained below.

Therefore, in this program processing, the crank angle θprna
The process for determining x will be explained with reference to FIG. 27.

This program uses the position signal from the crank angle sensor (
This is an interrupt processing program that is executed every 2"cA in synchronization with S2 (unit angle signal).

First, at 5TEP24 +, it is determined whether or not it is the A/D conversion start timing to cause the A/D converter of Ilo to A/D convert the detection signal S2n after the high frequency signal S2n.

This is A to detect the crank angle 17pmax.
/D conversion is necessary, and it is determined whether or not there is a rank angle area.
A/D from the position after a predetermined crank angle from the field
When conversion is started, a flag that is set when the crank angle θpmax is detected is checked, and A/D conversion is performed only while this flag is set.

And if it is the A/D conversion start timing.

bj 5TEP 242 uses a crank angle counter (
Soft counter) is counted up by +1.

After that, the A/D converter is activated in the 5TIEP 243, and the value of the detection signal S2n at that time is AID converted.
Perform conversion processing.

Then, in 5TER” 4, the A/D conversion value ΔDO read last time (initially 0) and the A/D conversion value A read this time.
D + (71 difference ΔP=Ar1]−ADO is calculated, and the difference ΔP and detection signal S2n are calculated in S1'1E11245.
A comparison is made with a predetermined reference value Δl''11 at which it can be determined that the signal level of the signal has reached the maximum (ΔP≧ΔPo).

At this time, if AP≧ΔF)o, in order to continue the A/r) conversion, the current A, /
Store the D conversion value ΔD I as A I') O (A
DO←A1”)1) On the other hand, if ΔP<ΔPo, the detection signal 8211
It can be determined that the signal level of OPM has reached the maximum.
From the count value of the crank angle counter at dx 247 and the crank angle at which A/D conversion was started, calculate the crank angle f) praax based on the one point of 1 death 51 when the pressure in the combustion chamber reaches the maximum. This calculated crank angle θpmax has some variation, so in order to smooth it, 5T
Moving average flpmax of the past n times (n = 4th to 8th place is appropriate) in EP248 = (n - 1) / n (previous Qpm
Find axJ+1/n (current θp+nax).

Thereafter, in 5TEP 249, the A/D conversion value ADO is cleared to zero for the next A/r1 conversion.

The crank angle B pmax at which the combustion chamber pressure reaches its maximum, in fact, the average value θpmax, is obtained by performing the above-described processing one after another.

Next, ignition timing control in this embodiment will be explained, but prior to that explanation, the principle of MBT control in this embodiment will be explained with reference to FIG. 28.

First, Fig. 28 is a diagram showing the change in engine shaft torque with θpmax as a parameter when the ignition timing is varied under a constant engine operating state (Ia speed and engine load). .

As the ignition timing is advanced, a point appears where the torque is maximum, and as shown in the figure, there is a flat region where the torque does not change much.

The most retarded ignition timing in this flat region, in other words, the minimum advance value that provides the maximum torque is MBT (Minj, m
un advance for Be5t Torqu
e) Yes.

The crank angle θpmax when the combustion chamber pressure reaches the maximum during this MBT is the target crank angle OM.

Then, this crank angle (in the flat area including IM, for example, 0.5
One of the two crank angles that provides 1 herk reduced by about 1% is the first 1.1 standard crank angle OM1 that is on the retarded side of the crank angle OVi, and the other is the second crank angle that is more advanced than the crank angle θM. Take the target crank angle OM2,
Therefore, if 1) new correction control of the ignition timing is stopped (held) when pnlax exists between OF/f and OM2, stable control can be achieved.

However, since the torque curve shown in FIG. 28 changes depending on the operating condition of the engine, the first. second target crank angle OM,
, (3M2 needs to be set according to the operating state of the engine.

Therefore, the first setting that was set in this way. Crank angle θpma for second target crank angle OM, OM2
The magnitude of x is determined, and when 0ρmax is between θMl and BM2 (referred to as the hold range as shown in FIG. 28), new correction control of the ignition timing is stopped.

On the other hand, when the crank angle θpmax is on the retarded side of the above hold range, that is, the first target crank angle BM, and on the more retarded side of the advance control range, the ignition timing is advanced and corrected, and Advance angle side, i.e. 2nd
When the crank angle 0 pIIlaX is in the retard control range on the advance side than the target crank angle θM2, the ignition timing is retarded and corrected, but in this case, as can be seen from Fig. 28, the unit change in the ignition timing is The amount of change in torque for (
Since the slope of the torque curve differs between the advance angle control range and the retardation control range, this is dealt with by changing the correction speed for each.

Next, ignition timing control will be explained. The normality/abnormality determination/ignition timing correction amount determination process shown in FIGS. 9 to 13 in the above-mentioned knock avoidance control example and the ignition timing correction amount determination process shown in FIG. Only the points different from the determination process will be explained, and the other explanations will be the same as those described above.

First, 5TEP 16 , 36 , 56 in the ignition timing correction amount determination process shown in FIGS. 10 to 13.

In determining whether the learning conditions in step 76 are satisfied, in addition to the learning conditions described above as the learning conditions, OH
, ≦Op+uax<OM 2 is also satisfied.

Next, 5TEPI 5.35° 55.7 in the ignition timing correction amount determination process also shown in FIGS. 10 to 13.
The ignition timing correction amount calculation process in step 5 is changed to the process shown in FIG.

Therefore, the ignition timing correction mouse calculation process shown in FIG. 29 will be explained. First, 5TEP25] to 2
Each process of 67 is the same as the process of 5TEP91 to 10-7 in FIG.

In this process, /B>SI in 5TFP252
-, that is, when /B≦SL and the knocking level is below the reference level, proceed to 5TEP268 and calculate the crank angle F) for the ignition timing correction amount dc.
The only difference from the process shown in FIG. 14 is that MBT correction processing is executed to perform correction according to the detection result of max.

That is, when the knocking level exceeds the reference level, knocking avoidance control is preferentially executed, and MBT control is additionally executed only when the knocking level is below the reference level.

Therefore, this MBT correction processing will be explained with reference to FIG. 30.

First, in the 5TEPs 271 and 272, the above-mentioned first target crank angle 8M1 and second target crank angle (1M2) when performing feedback control of the ignition timing based on the average value 675 of the detected crank angles θpmax are stored in the ROM. This is obtained by looking up a data table stored in advance in the table using engine rotational speed data and engine load data, respectively.

Thereafter, the 5THP 273 performs a table lookup on a data table previously stored in the ROM using the engine speed data and the engine load data to determine the basic feedback correction amount ΔFBO for the ignition timing.

This data table is provided as a basic quantity when determining the amount of correction of ignition timing, since the amount of change in ignition timing per unit herk change in the advance or retard range varies depending on the engine operating conditions. .

Then, the crank angle θp detected by 5TIEP274
max average value Qpmax and first target crank angle n
1) If luaX < OM %, compare the average value flpm with the second target crank angle BM2 at 5TEP 275. It is determined whether 61 stones≧θM2.

Then, the results of these determinations are flM,≦ilowi〈
If it is 0M2, that is, if it is in the above-mentioned hold region, the process returns without correcting the ignition timing correction amount dc (5TEPI 6.36 in Figs. 10 to 13,
56. Proceed to 76).

For Goku, the judgment result for 5TOP274 is θpm
If ax<0M1, advance correction of the ignition timing correction amount dc is performed in 5TEP276 to 279.

In other words, at 5TEP276, the first target crank angle O
Deviation between M and the average value opΩlaX Δθ=θJ −θ
Calculate pHlaX.

Then, in 5TEP 277, the correction coefficient kl for the basic feedback correction amount 8FBO is looked up in a data table previously stored in the ROM, for example, as shown in FIG.

A value of 1 for this correction coefficient means that the deviation Δθ is greater than or equal to a certain value...
1 Above, we have given a magnitude proportional to the deviation Δ0, and when the deviation Δ0 is large, the ignition timing correction amount becomes large. The speed characteristics are determined.

After that, in 31 King P278, the modification 18 FB is multiplied by the basic feedback modification amount 8 FIFO by the modification coefficient kl (ΔFB
=, XΔFBO).

Then, at 5TEP 279, the correction amount ΔF +3 is added to the ignition timing correction amount dc (correction to the advance side) to obtain a new ignition timing correction amount dc, and then the process returns.

Also, the judgment result is 67-≧θM2 at sTt+p 275
If so, the ignition timing correction amount i with 5TEP280-283
Perform retardation (ReLard) correction of Jc.

In other words, the deviation of the second target crank angle θM2 from the average value 0pIIlax at 5TEI"280 Δo=oVI
Calculate 2-θpmax.

Then, in S1'l''jP2 R1, 2 is stored in advance as a correction coefficient for the basic feedback correction amount ΔFBO in the ROM, and a data table as shown in FIG. 31, for example, is looked up as a deviation.

A value of 2 for this correction factor is equivalent to a value of 1 for the correction factor.
1, the relationship 2≧1 is set, and a second correction speed on the retarded angle correction side is determined which is relatively faster than the first correction speed characteristic on the advance angle correction side.

After that, in 5TEP282, the correction amount ΔFB is multiplied by the basic feedback correction amount ΔFBO and the correction coefficient by 2 (ΔFB
= 2 x ΔFBO).

Then, in 5TEr' 283, the correction amount ΔFB is subtracted from the ignition timing correction amount dc (correction to the retard side) to obtain a new ignition timing correction amount dc, and then the process returns.

By adding MBT control to knock avoidance control in this way, fuel efficiency, output, and drivability can be further improved.

In each of the above embodiments, an example was described in which a combustion pressure vibration detection means was provided for each cylinder, but it is also possible to control the ignition timing of a plurality of cylinders (a group of cylinders) with one combustion pressure vibration detection means. The same can be implemented in the control device.

〔Effect of the invention〕

As explained above, according to the present invention, there is provided a normality/abnormality determining means for determining whether the detection of combustion pressure vibration by the combustion pressure vibration detecting means is normal or not, and a determination result of the normality/abnormality determining means is normal. In some cases, the ignition timing correction amount is determined based on the detection result of the combustion pressure vibration detection means, and when the judgment result of the normality/abnormality judgment means is abnormal, the ignition timing correction is performed for other cylinders or cylinder groups whose judgment results are normal. Since the ignition timing correction amount determining means is provided to determine the ignition timing correction amount based on the amount of ignition timing correction, a malfunction of the combustion pressure vibration detection means will cause the ignition timing control to become abnormal, resulting in a decrease in generated torque, a decrease in fuel efficiency, and a decrease in exhaust temperature. ” This will not cause any inconvenience such as increase in weight.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention, and FIG.
3 is a schematic configuration diagram of a control device for an internal combustion engine embodying the present invention, and FIG. 3 is a block diagram showing an example of the control unit of FIG. 2. 4 is a sectional view and a plan view showing an example of the cylinder pressure sensor, FIG. 5 is a circuit diagram showing an example of the charge amplifier, and FIG. 6 is a block diagram showing an example of the signal processing circuit. FIG. 7 is a circuit diagram showing a specific example of a part of the signal processing circuit. FIG. 8 is a timing chart diagram for explaining the integrator integral assistance control process executed by the main control circuit, and FIG. Flowcharts showing an example, FIGS. 10 to 13 respectively show the first cylinder in FIG. 9. A flowchart showing an example of the correction amount determination process for the second, third, and fourth cylinders. FIG. 14 is a flowchart showing an example of the ignition timing correction amount determination process during normal conditions in FIGS. 10 to 13. , FIG. 15 is an explanatory diagram showing an example of the frequency of occurrence of the /B value in each knock phenomenon to provide an explanation of FIG. 14, and FIG. 16 shows an example of the ignition timing determination process executed by the main control circuit. Flow diagram. FIG. 17 is a diagram showing the interlayer rotation speed/intake air flow rate-advanced angle value characteristics for explaining the basic ignition timing calculation process in FIG. 16. FIG. 18 and FIG. FIG. 20 is a flowchart and a diagram for explaining another example of the determination process. Similarly, FIG. 22 is a block diagram showing an example of the signal processing circuit, FIG. 22 is a flow chart showing an example of normality/abnormality determination and ignition timing correction amount determination processing executed by the main control circuit, and FIGS. 23 to 26 are: A flowchart showing an example of the correction amount determination process for the first, second, third, and fourth cylinders shown in FIG. 12, respectively, and FIG. Flowchart showing the detection process, FIG. 28 is a diagram for explaining the basic principle of the <MINT control, FIG. 29 is a flowchart showing the ignition timing correction amount determination process, FIGS. 30 and 31 1 is a flowchart showing the MBT correction processing and a diagram for explaining the same. 11... Control units 1-13... Crank angle sensors 21A-210... Cylinder pressure sensors 31A-3111 ...Charge amplifier 33.45...
・Signal processing circuit 33r)...Integrator 34...
Main control circuit 40...Ignition device JP-A-6
1-10697G (25) Fig. 18a Fig. 19 Ignition timing 'f8fmOHG1-10G97G (34) Fig. 31 Δe

Claims (1)

[Scope of Claims] 1. A plurality of combustion pressure vibration detection means for detecting combustion pressure vibration of each cylinder are provided, and an ignition timing correction amount is determined based on the detection result of the combustion pressure vibration detection means, and the ignition timing correction amount is determined for each cylinder or each cylinder. A control device for an internal combustion engine that controls ignition timing for each cylinder group includes a normality/abnormality determination means for determining whether detection of combustion pressure vibration by the combustion pressure vibration detection means is normal; When the determination result is normal, an ignition timing correction amount is determined based on the detection result of the combustion pressure vibration detection means, and when the determination result of the normality/abnormality determination means is abnormal, other cylinders whose determination result is normal are determined. or ignition timing correction amount determining means for determining the ignition timing correction amount based on the ignition timing correction amount of the cylinder group. 2. The control device for an internal combustion engine according to claim 1, wherein the combustion pressure vibration detection means includes means for detecting a knocking level of the engine. 3. The ignition timing correction amount determining means selects the most retarded ignition timing correction amount among the ignition timing correction amounts for other cylinders or cylinder groups for which the determination result is normal, and the ignition timing correction amount for the cylinder or cylinder group for which the determination result is abnormal. A control device for an internal combustion engine according to claim 1 or 2, further comprising means for setting a timing correction amount. 4. The combustion pressure vibration detection means according to any one of claims 1 to 3, wherein the combustion pressure vibration detection means includes means for detecting a crank angle (θpmax) when the combustion chamber pressure of the engine reaches a maximum. Ignition timing control device for internal combustion engines. 5. The ignition timing correction amount determining means includes means for setting the average value of the ignition timing correction amounts of other cylinders or cylinder groups for which the determination result is normal as the ignition timing correction amount for the cylinder or cylinder group for which the determination result is abnormal. A control device for an internal combustion engine according to any one of claims 1 to 4.