JPH01310148A - Controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide always the maximum output by stopping the feed-back of air fuel ratio in a predetermined load region of an engine and correcting fuel supply or ignition timing so that the maximum pressure value, average effective pressure and estimation parameter are directed in the maximum direction. CONSTITUTION:A controller 15 receives signals from an air flow meter 2, an intake pipe pressure sensor 2a, a water temperature sensor 6, a crank angle sensor 7, an exhaust sensor 9, an in-cylinder pressure sensor 13, etc. to obtain the maximum pressure-value and average effective at every combustion cycle from pressure in a combustion chamber and crank angle, an estimation parameter A from intake amount, rotational frequency and average effective pressure and an estimation parameter B from intake pipe pressure and average effective pressure. Fuel supply or ignition timing is corrected to direct the maximum pressure value, average effective pressure, estimation parameter A or B to the maximum so that ignition coils 17 are respectively controlled through a fuel injection valve 10 and power unit 16. Thus, the maximum output and efficiency can be always obtained even if individual engines have dispersion.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a control device for an internal combustion engine that can always obtain maximum output and maximum efficiency even if there are variations in performance among individual engines. It is.

[Conventional technology]

BACKGROUND ART Conventionally, devices have been used that calculate appropriate fuel supply amount and ignition timing based on the relationship between engine intake air amount or intake pipe pressure and engine speed, and control fuel injection valves and ignition devices.

Furthermore, Japanese Patent Application Laid-open No. 85148/1983 discloses a control device that detects the combustion pressure of an engine, adjusts it to a predetermined value, and performs more accurate control.

This device detects the combustion state based on the output of the cylinder pressure (combustion pressure) sensor installed in each cylinder, and adjusts the combustion injection timing and EGR (
This controls the exhaust gas recirculation (exhaust gas recirculation) valve, etc.

[Problem to be solved by the invention]

With the above-mentioned conventional equipment, combustion pressure is controlled to match the combustion pattern predetermined by a standard engine.When producing large quantities of engines, there is considerable variation, and the true requirements of each engine vary. The combustion patterns to be used vary from one engine to another, and even if the combustion pressure is controlled according to a standard pattern, it cannot be said that the control accuracy will be improved, and the performance of the engine may be deteriorated by this control.

In addition, conventional devices control fuel injection timing, EGR rate, etc. as operational parameters to control combustion pressure.
The engine's output performance can be effectively controlled by the combustion injection amount and the optimal ignition timing.

In general, the range in which fuel injection amount can be freely controlled is limited in order to suppress exhaust gas components to a low level.
It is necessary to control fuel injection amount and ignition timing in a complex manner to achieve both exhaust gas components and output performance.

This invention was made to solve the above-mentioned problems, and provides a control device for an internal combustion engine that can always optimally control the combustion state of the engine in accordance with the operating conditions and obtain maximum output and efficiency. The purpose is to

[Means to solve the problem]

The control device for an internal combustion engine according to the present invention provides an intake air amount Q of the engine.
Evaluation parameter A-Pt/(Qa/N) obtained by calculating the average of a, rotation speed N, and Pb, or evaluation parameter B obtained from intake pipe pressure Pb and average effective pressure Pi = P
+/P h or maximum pressure value Pb for each combustion cycle
．． 8 or a control device that corrects the fuel supply amount Qa or the ignition timing θi in a direction in which the average effective pressure Pb becomes maximum, and performs control based on the correction result.

Further, a control device for an internal combustion engine according to a second aspect of the invention is provided with a control device that performs feedback control on the fuel supply amount Qa and corrects the ignition timing by the correction means.

Furthermore, the control device for an internal combustion engine according to the third invention performs feedback control in a predetermined load operating range of the engine, and performs feedback control in other operating ranges. This system is equipped with a control device that stops the fuel supply and corrects the fuel supply amount Qf.

[For production]

The control device in this invention controls the maximum pressure value P @mX for each combustion cycle based on the combustion chamber pressure Pc and the crank angle θc.
Or find the average effective pressure Pb and calculate this pressure maximum value P@MK
Fuel supply IQ in the direction in which % average effective pressure P8 and evaluation parameter A or B become maximum.

Alternatively, the ignition timing θi is corrected, and fuel is supplied to the engine based on the corrected fuel supply amount Qa, or ignition control is performed based on the corrected ignition timing θi.

Further, the control device in the second invention detects the air-fuel ratio based on the combustion gas components detected by the exhaust sensor, feedback-controls the fuel supply IIQa so that the air-fuel ratio becomes a predetermined value, and controls the fuel supply IIQa to a maximum pressure. Value P. 8. Correct the ignition timing θc in a direction that maximizes the average effective pressure Pb and the evaluation parameter A or B.

Furthermore, the control device in the third invention detects the air-fuel ratio based on the combustion gas components detected by the exhaust sensor, feedback-controls the fuel supply amount Qa so that the air-fuel ratio becomes a predetermined value, and controls the engine. In the specified load operating range,
This feedback system 9B is stopped, and the fuel supply amount Qf is corrected in the direction in which the maximum pressure value Pb11111, the average effective pressure Pb, and the evaluation parameter A or B become maximum.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. Fig. 1 is a configuration diagram showing the main configuration of one embodiment, where ■ is an air cleaner, 2 is an air flow meter that measures the amount of intake air, 3 is a throttle valve, 4 is an intake manifold, 5 is a cylinder block, 6 is a 7 is a water temperature sensor that detects the engine cooling water temperature, and 7 is a crank angle sensor.

The crank angle sensor 7 outputs a reference position pulse for each crank angle reference position (every 180 degrees for a 4-cylinder engine, every 120 degrees for a 6-cylinder engine), and also for every unit angle (for example, every 1 degree). Outputs an angular pulse.

8 is an exhaust manifold, 9 is an exhaust sensor that detects the concentration of exhaust gas components (for example, oxygen concentration), 10 is a fuel injection valve,
11 is a spark plug, 13 is an in-cylinder pressure sensor (hereinafter referred to as a combustion pressure sensor) that detects the cylinder pressure, and 15 is an iTJ device.

In the control device 15, by calculating the number of unit angle pulses after this reference position pulse is input, the crank angle at that time can be determined.

Furthermore, the rotational speed of the engine can be determined by measuring the frequency or period of the unit angular pulse.

Although the example in FIG. 1 shows a case in which the crank angle sensor is provided within the distributor, the crank angle sensor may be provided directly on the crankshaft.

Reference numeral 2a designates an intake pipe pressure sensor, and either the output of this sensor or the output of the air flow meter 2 is used for feedbank control of the fuel supply amount and ignition timing.

The control device 15 has a configuration as shown in FIG.

In the figure, 151 is an A/D (analog/digital) converter, which includes the output 31 of the air flow meter 2 or the output Sla of the intake pipe pressure sensor 2a, the output S2 of the water temperature sensor 6, the output S4 of the exhaust sensor 9, and the combustion pressure sensor 13. The output S6 of is input.

152 is an input interface, into which the output S3 of the crank angle sensor 7 is input.

153 is a CPU, ROM 154 and RAM
155, the input is processed and controlled according to a predetermined program.

156 is an output interface that receives the output of the CPU 153 and outputs the output S5. Generate S7.

The output S5 is a pulse signal that drives the fuel injection valve 10, and the amount of fuel supplied is controlled by the pulse width j'11.

Further, the output S7 is an ignition timing signal, which is amplified by the power unit 16, and the ignition coil 17 is driven by the output S8 from the power unit 16.

The output S9 of the ignition coil 17 is distributed as an output 510 by the distributor 18 to the spark plugs 11 provided in each cylinder.

Next, the operation will be explained. The basic fuel injection control and ignition timing control methods based on the output of the air flow meter 2 or the intake pipe pressure sensor 2a in the device shown in FIG. 1 are well known, so a detailed explanation will be omitted. Only the operation according to the invention will be described in detail.

First, the relationship between the combustion pressure Pc and the crank angle θ° will be explained with reference to FIG. 3. The output S6 of the combustion pressure sensor 13 has a maximum value near the crank angle top dead center (TDC). Let this oak maximum value be P□yo.

Furthermore, the average effective pressure Pm (M internal pressure) can be determined by integrating the combustion pressure Pc over one cycle as shown below.

Here, ■ is the stroke volume of the piston, and ■1-1×
(bore diameter) 8×r, and ■ is cylinder internal volume, connecting rod length l, piston stroke r1, crank angle θc
Therefore, it can be expressed as ...(2), so it becomes ...(3).

Therefore, the average effective pressure Pi can be calculated by substituting equation (3) into equation (1).

The average effective pressure Pi determined as described above is a well-known parameter that directly detects the output generated by the engine.

Next, it can be calculated from the above average effective pressure Pi and the engine intake air IQa obtained from the output S1 of the air flow meter 2, or the intake pipe pressure Pb obtained from the output Sla of the intake pipe pressure sensor 2a, and the rotation speed N obtained from the crank angle. Below A,
The parameter B is also useful as a parameter for evaluating the combustion energy extracted from the amount of air per stroke (Qa/N or Pb) taken into the engine, that is, the efficiency.

A=Pt/(Q-/N)...(4
)B=Pi/Pb...(5
) These evaluation parameters (Pb, , Pi, A, B)
Typical relationships among the air-fuel ratio, the ignition timing, and the air-fuel ratio are shown in FIGS. 4 and 5.

In FIG. 4, P IIIM and Pi have maximum values, and it is shown that if the air-fuel ratio is controlled so that these parameters become maximum, the maximum output can be obtained.

Furthermore, evaluation parameters A and B are parameters that indicate the combustion energy that can be extracted from the amount of intake air per stroke, and it is known that efficiency is optimized when the air-fuel ratio is controlled to maximize this.

In FIG. 5, it is shown that as P□ advances the ignition timing θ, P as increases, but the average effective pressure Pb and evaluation parameters A and B have maximum values.

In an engine with such characteristics, the mean effective pressure Pb
By controlling the ignition timing so that the engine speed and evaluation parameters A and B are maximized, maximum output and optimum efficiency can be obtained.

The above control is specifically shown in the flowcharts of FIGS. 6(a) and 6(b). FIG. 6(a) is a flowchart for detecting combustion pressure, and in step 101, the output θC of the crank angle sensor is read. This value may be determined by a crank angle sensor that counts pulses generated every 1° of crank angle, or may output a code corresponding to the angle.

Next, in step 102, the output Pc of the combustion pressure sensor 13 is read. This reading is performed every 1 degree of the crank angle, for example.

Then, in step 103, Pc is P′ a m
Read whether it is greater than II. Since this P'aax is cleared at the beginning of one combustion cycle, the first reading Pc is P'1. bigger. Therefore, in step 104, Pc is held at P'mar.

Next, in step 105, the mean effective pressure p1 is calculated using the above formula.
At step 6, the value of the crank angle signal θc is determined, and it is determined whether one cycle of combustion has been completed, and if it has not been completed, the process returns to step 101 again.

In this way, while Pc increases, P'l1mK is updated to larger values one after another in step 104,
When Pc starts to decrease, the process in step 104 is omitted, so that the maximum value of Pc during one cycle is held at P'*mm.

At the end of the l cycle, the process moves from step 106 to step 107, where P',1, is stored in Pb1, then in step 108, P', is stored in Pb, and in step 109
After clearing P' +++ a m and P'8 at
The processing from step 101 onward is performed again in response to a new cycle.

The above P aAX and Pi are used for the following fuel control and ignition timing.

Fig. 6(a) is a flowchart for controlling the fuel injection amount so that the average effective pressure Pb obtained in Fig. 6(a) becomes the pilot flame. Although not shown in the figure, the initial value Pi of the average effective pressure P4
(.+Pi(1) is set to 0.

In this FIG. 6(b), step 201 is the n of combustion.
- Mean effective pressure Pi maintained in the first cycle.

That is, Pb. -1, and step 202 similarly reads the average effective pressure P held at the nth cycle.
Eing, that is, Pb. , is to be read.

Then, in step 203, P t + , ) and Pi+1-1 . In the initial stage of determining the magnitude relationship of P
Since r (+1 ” P i (al), the process moves to step 204.

T7 is the pulse width that drove the fuel injection valve last time, and is initially set to the pulse width T.

This pulse width T6 is the reference air-fuel ratio (A/
F) is the pulse width corresponding to 0. The pulse width is frozen by ΔT from this pulse width T, and is set to T, which is used as the next pulse width.

Next, in step 206, the fuel injector is pulsed with TI.
Only drive. Since the pulse width T is smaller than To by ΔT, and therefore the air-fuel ratio shifts toward the lean direction in FIG. 4, the average generated by this injection can be expressed as the dynamic pressure P.
i, z, are Pi. Become bigger.

This average effective pressure (Pill) is read in step 207. In step 20B, the average dynamic pressure P r +Ill is replaced with Pi (1), and in step 209, the average effective pressure P
Change b, 1 to Prtz, 2W, and then (Z f, 2
After replacing the pulse width T6 with T1 in step 10, step 20
Return to 1.

In this way, each time ΔT is reduced in step 204, the pulse width T□ becomes smaller, and the optimum air-fuel ratio (
A/F). , 7 approaches the pulse width T0, which corresponds to 7.

When T□ becomes smaller by exceeding the pulse width T OFFT, the average effective pressure PL reversely decreases.

Therefore, in step 203, Pill)<P
i 1m-1, the process moves to step 205 and conversely the pulse width T7. ．． is set to a value larger than the previous value T7 by ΔT.

By repeating this operation, the pulse width T B + 1
is focused in the vicinity of T, , and therefore the average effective pressure Pb
is adjusted near the local maximum value. At this time, it is better that the value of the pulse width ΔT that is adjusted at one time is as small as possible.The reason is that when the pulse width ΔT is large, the pulse width Taft becomes T
This is because the value increases and decreases before and after OFT, and stable driving cannot be achieved with a value sufficiently close to TOP.

Furthermore, since FIG. 6) is a simplified diagram for easily explaining the operating principle, the following malfunction may occur.

That is, the current pulse width T is To and T. When it is between P7, the pulse width T can be focused on Ta□ by performing the subtraction in step 204.
When adding 5, the average effective pressure Pi decreases, so
In the next cycle, addition is performed in step 205 from the determination in step 203, and the pulse width gradually becomes pulse width T0.
It diverges in the direction. This kind of inconvenience is explained in Figure 6 (C
) can be improved using logic such as

FIG. 6(C) shows only the improved points, and the other parts are the same as FIG. 6(b). In this FIG. 6(C), when step 303 is subtracted in step 204,
Step 304 sets flip-flop I to 1 when the addition is made in step 205. After processing step 304 or step 303, step 20
Move on to 6.

In the next cycle, after the determination in step 203, step 3
The value of flip-flop I is determined at 01,302. When moving from step 203 to step 301, the previous 1
When it is set to -0, the average effective pressure Pb increases as a result of subtracting the pulse width, so step 2 is performed again.
Subtraction is performed in 04 to bring the pulse width T, l□ closer to the Topt direction.

If it is Fri-Ambi-Fromb I-1, the average effective pressure Pb has increased as a result of adding the previous pulse width, so the pulse width is T. To the right of P7 (i.e. T , , +
+ < T 6pt ), and step 2
05, the pulse width T1°1 is brought closer to TIIFT. The operation in step 302 is also the same as above.

As is clear from the above explanation, the flip-flop ■ in this figure is used to determine whether the pulse width T,... is to the right or left of T,... This can prevent accidental divergence in the opposite direction.

It goes without saying that when the pulse width is set to T in the initial state, the flip-flop (2) is also initially set to 0.

The average effective pressure P is determined by the zero ignition timing θi described above regarding the method of controlling the average effective pressure P8 by controlling the fuel supply amount using FIGS. 6(a) to 6(C).

The method for controlling the ignition timing can be easily understood by replacing the pulse width T in the figure with 0 ignition timings, so a detailed explanation will be omitted.

In addition, maximum combustion pressure value P□ and evaluation parameter A=P
Control z/(Q-/N) or B=Pb/Pb to maximum m
Regarding the method of calculating the mean effective pressure P in the same figure.

Since it can be easily understood by replacing these parameters, detailed explanation will be omitted.

Next, another embodiment of the present invention in which the above control method is actually applied will be described. FIG. 7 illustrates an example of maximum value control according to the present invention in a device that feedback-controls the air-fuel ratio to a predetermined value using an exhaust sensor.

In the figure, step 401 is for determining whether or not to perform air-fuel ratio measurement using the exhaust sensor, based on the operating conditions of the engine and whether or not there is a failure in the exhaust sensor.

When executing this control, the process moves to step 402 to read the output of the exhaust sensor 9, and then, in step 403, the fuel supply amount is feedback-controlled so that the output of the exhaust sensor becomes a predetermined value.

Since the content of this control is conventionally known, a detailed explanation will be omitted.

Next, in step 404, the ignition timing θ is adjusted.

is controlled so that the evaluation parameters Pb, . . . Pb, A or B are maximized. The content of this control is the maximum value control explained in FIGS. 6(a) to 6(C).

Next, in step 401, the air-fuel ratio feedback control i
When it is determined that B is not executed, the process moves to step 405.
The fuel supply amount Qf is controlled so that the evaluation parameter P□, , Pb, A or B becomes maximum. This control is also shown in Figure 6 (
This is explained using FIGS. 6(a) to 6(c).

Next, the ignition timing θi is controlled by the process of step 404. The configuration shown in this diagram is to avoid performing maximum value control based on the fuel supply amount Qf when performing air-fuel ratio feedback control, and the air-fuel ratio is given priority in order to keep exhaust gas components below a predetermined level. This is because it is controlled by

FIG. 8 shows a method of averaging the evaluation parameters used for the above-mentioned control. In the figure, step 50
1 is the parameter Xi (Pb, , Pi.

The value A or B indicates the value of the i-th cycle of combustion, and specifically corresponds to the output of steps +07 and 108 in FIG. 6(a)], and is successively integrated in step 502.

Step 503 determines whether the cumulative number has reached n cycles. If not, the process returns to step 501; if it has, the process moves to step 504, where the cumulative value is divided by n and averaged. (Determine I
, even if the engine is operated at the same ignition timing of 01°, the combustion pressure Pb
Furthermore, since the evaluation parameters Pb□, Pb, A, or B may fluctuate slightly, this is done in consideration of the possibility that this may interfere with the local maximum value control.

Considering that averaging slows down learning, it is necessary to set n within an allowable range for control purposes. After averaging, the integrated value is cleared in step 505.

Although Figure 8 shows a simple method of arithmetic averaging,
Other well-known weighted average or moving average methods can also be used.

In the maximum value control described above, it is desirable to set a limit on the control n range of ignition timing control and fuel supply amount control, because if the ignition timing is too late, misfire may occur.
This is because damage occurs due to an excessive rise in exhaust gas temperature, and conversely, if the exhaust gas temperature progresses too much, a decrease in output and damage occur due to abnormal combustion, and the same problem occurs when the amount of fuel supplied is too high or too low.

This restriction can be achieved by comparing the control parameters ignition timing θi9 and fuel injection pulse width with predetermined upper and lower limits, and if they exceed the upper and lower limits, control is performed using the upper and lower limits. Since the logic is simple, explanation using drawings will be omitted.

Next, in the explanation of FIG. 6(c), it was stated that the pulse width ΔT (Δθi in the case of ignition timing), which is adjusted every cycle, should be kept small.

However, the fact that this addition/subtraction value is small means that the pulse width (
This means that the speed at which the ignition timing (ignition timing) converges to the optimum value becomes slower, which is undesirable for controlling engines whose operating conditions are constantly changing.

In order to solve such problems, the operating state of the engine is divided into zones according to operating parameters, and for each zone, maximum value control is performed using the injection pulse width T7 or ignition timing θif(,,1'), and the two control results are T7 and θig (*1
can be held in a memory provided corresponding to each zone, and this memory can be held even if the power is turned off.

In this way, when the engine restarts or shifts from one operating state to another, the control parameters T7 and θi*Zal of the local maximum control described above
Since the correction is started from near the optimum value, the focusing becomes faster and a preferable control jn is possible.

In order to enable this control B, the RAM 15 in FIG.
The contents may be retained by making RAM 155 a non-volatile memory or by backing up the power supply of RAM 155 with a battery.

FIG. 9 is a diagram showing an example of zone classification of operating states and memory allocation. The horizontal axis is the rotation speed N, N.

It is divided into Nz and Ns. The vertical axis Y is a parameter indicating the engine load, and is similarly divided into Yl, Yl, Ys, and Ya using intake air amount Qa, Q/N obtained by dividing this by rotational speed N, or intake pipe pressure Pb. has been done.

Zone division is performed based on these divisions, and memory Mr1. - and Mf)! , , is the memory that holds the control parameters T, , M
θ is a memory that holds the control parameter θi@lnl, and 29m indicates the division number on the horizontal and vertical axes, respectively.

When within these zones, perform the maximum value control,
The control parameters are sequentially written and held in the memories My and Mθ. In the example shown in FIG. 9, zones are divided using two parameters: the rotation speed N and a parameter Y indicating the engine load, but it goes without saying that zones may be divided using N or Y alone.

Note that since the control logic in FIG. 9 is simple, explanation of the logic with reference to the drawings will be omitted.

The control parameters held in the memories M and Mθ can be focused on appropriate values when the vehicle is stably operated within the corresponding zone.

However, in an engine in which acceleration and deceleration are frequently repeated, maximum 4Ii control is performed in response to transient combustion conditions, and there is a risk that a value that significantly deviates from the normal value may be maintained.

In order to solve this kind of inconvenience, it is recommended to use a filter as shown in FIG. 10. In FIG.
l1 (the value in step 210 in FIG. 6(b)), and in step 602, the value To(old) previously held in the memory M7 is read out, and this T7 and To(o
In step 603 according to ld), To(new) = (1-K)・To(old) 10K
T11, where 0<K≦1, is calculated.

What this operation means is that the result T7 obtained this time is reflected in the memory and the new held value T-(new) is created.
is to occur. The value of is determined by balancing the need to moderate the convergence speed of the retained value and to suppress deviated correction values during transient times.

Next, in step 604, the pulse width T is stored in the memory M.
o (new) is written and the process returns to step 601.

The value T0 held in the memory M is used as the initial value of the pulse width T7 when starting the maximum value control shown in FIG. 6(b).

In FIG. 1θ, the circulation of steps 601 to 604 can be synchronized with the maximum value control in FIG.
A slower period can also be selected.

In addition, in this FIG. 10, the controlling parameter is set to pulse width T7.
It goes without saying that the ignition timing θigC++1 can also be held in the memory Mθ with the same configuration.

It is appropriate to stop executing the above maximum value control when the operation of the combustion pressure sensor 13 is abnormal. Therefore, the range of values that are output when the combustion pressure sensor 13 is normal is determined in advance, and when a value exceeding this range is output, a flag is set to prohibit the maximum value side jI, and as shown in FIG. (a)
When starting local maximum value control, it is recommended to read this flag and prohibit control when it is in the set state.This logic is simple, so explanation with drawings will be omitted.

Note that whether or not the output of the combustion pressure sensor 13 is normal is determined not only by the combustion pressure Pc directly output from the combustion pressure sensor 13 but also by the maximum value P of this combustion pressure Pc. .

It is preferable to use at least one value of the average effective pressure P6 or the average effective pressure P6.

〔Effect of the invention〕

As described above, according to the first invention, the maximum pressure per combustion cycle is 41LPb, the average effective pressure P8, and the evaluation parameter A or B is maximized based on the fuel supply amount Qf or the ignition timing θ. Further, according to the second invention, the fuel supply amount Qt is subjected to feedbank control so that the air-fuel ratio becomes a predetermined value, and the pressure maximum value Pb□ and the average effective pressure are P i , evaluation parameter A
Alternatively, according to the third invention, the fuel supply amount Qa is feedback-controlled so that the air-fuel ratio becomes a predetermined value, and the engine In a predetermined load range, the feedback control is stopped and the maximum pressure value P
Since the fuel supply amount Qa or the ignition timing θc is corrected in the direction in which the evaluation parameter A or B is maximized, maximum output and maximum efficiency can always be obtained even if there are variations among individual engines.

Furthermore, it is possible to prevent interference between the feedback control of the air-fuel ratio by the exhaust sensor and the maximum value control by the combustion parameters, and it is possible to increase the output and efficiency while keeping the exhaust gas components below a predetermined level.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a control device for an internal combustion engine according to an embodiment of the present invention, FIG. 2 is a block diagram showing the internal configuration of the control device in the embodiment of FIG. 1, and FIG. FIGS. 4 and 5 are characteristic diagrams showing an example of the combustion pressure waveform in the embodiment, and FIG. ) to FIG. 6(C), FIG. 7, and FIG. 8 are flowcharts showing the flow of operation for performing local maximum value control of the present invention, respectively, and FIG. 9 is a zone of the operating state for explaining the present invention. FIG. 10 is an explanatory diagram showing an example of partitioning and memory allocation, and is a flowchart showing the flow of operations when dealing with a transient state in the present invention. 2...Air flow meter, 2a...Intake pipe pressure sensor, 6...Water temperature sensor, 7...Crank angle sensor, 9
...Exhaust sensor, 10...Combustion injection valve, 11...
Spark plug, 13... Cylinder pressure sensor (combustion pressure sensor)
, 15...control device. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent Masuo Oiwa Figure 2, Cause 3 Figure 4 People To Tapr - Figure 5 Figure 6 (a) Figure 6 (b) Figure 6 (C) Figure 9 Figure 10

Claims (3)

[Claims] (1) An air flow meter that measures the intake air amount Q_a of the engine, an intake pipe pressure sensor that detects the intake pipe pressure P_b of the engine, a crank angle sensor that detects the rotation angle θ_c of the engine, and a combustion chamber of the engine. at least one in-cylinder pressure sensor that detects the pressure P_c, determines the fuel supply amount Q_f and ignition timing θ_i according to the intake air amount Q_a or the intake pipe pressure P_b and the rotation speed N of the engine, and determines the combustion chamber pressure. The maximum pressure value P_m_a_x or the average effective pressure P for each combustion cycle is determined by P_c and the rotation angle θ_c.
_iFurthermore, the evaluation parameter A=P_i/(Q_a/
N) Or, from the intake pipe pressure P_b and the average effective pressure P_i, calculate at least one of the evaluation parameters B=P_i/P_b and determine if the maximum pressure value P_m_a_x, the average effective pressure P_i, and the evaluation parameter A or B are maximum. A control device for an internal combustion engine, comprising: a control device for correcting at least one of the fuel supply amount Q_f or the ignition timing θ_i in a direction in which the fuel supply amount Q_f or the ignition timing θ_i is controlled so as to control the fuel supply amount or the ignition timing based on the corrected value. (2) The control device determines the air-fuel ratio based on the exhaust gas component concentration, and feedback-controls the fuel supply amount Q_f so that the air-fuel ratio becomes a predetermined value, and also controls the maximum pressure value P_m_a_x, the average effective pressure 2. The control device for an internal combustion engine according to claim 1, wherein the ignition timing θ_i is controlled so that P_i and the evaluation parameter A or B are maximized. (3) The control device determines the air-fuel ratio based on the exhaust gas component concentration, and feedback-controls the fuel supply amount Q_f so that the air-fuel ratio becomes a predetermined value, and in a predetermined load operating range of the engine. , performs feedback control to obtain the maximum value P_m_a_x and the average effective pressure P.
_i, the ignition timing θ_i is controlled so that the evaluation parameter A or B becomes maximum, and the feedback control is stopped in other operating ranges other than the predetermined load operating range of the engine, and the maximum value P_m_a_x, 2. The control device for an internal combustion engine according to claim 1, wherein the fuel supply amount Q_f is controlled so that the average effective pressure P_i and the evaluation parameter A or B are maximized.