JPH0633722B2 - Knotting control device for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a device for controlling knocking by controlling an intake air amount or an ignition timing of an internal combustion engine such as an automobile.

(Prior Art) Internal Combustion Engine (hereinafter sometimes simply referred to as "engine")
It is necessary to optimally determine the ignition timing of the engine according to the operating state of the engine. Generally, considering the efficiency and fuel efficiency of the engine, the minimum advancing angle at the time of maximum torque, so-called MBT (Minimum adva
It is known that it is best to ignite in the vicinity of nce for Best Torque), and so-called MBT control is performed in which the ignition timing is changed to MBT according to the operating state of the engine.

However, under certain operating conditions, knocking may occur as the ignition timing is advanced, and stable engine operation may not be possible. For example, at low load and low speed rotation, the knocking limit is reached before MBT. Also,
The knock limit is easily affected by atmospheric conditions such as temperature and humidity.

Therefore, a system has been developed in which so-called knocking control, which controls ignition timing depending on the presence or absence of knocking, is used in combination with the above MBT control. For example, such a system is disclosed in JP-A-58-82074. There is a described device.

In this device, the pressure in the combustion chamber (hereinafter referred to as cylinder pressure)
Is detected, and the ignition timing is MBT-controlled so that the crank angle (hereinafter referred to as the combustion peak position) θ _pmax at which the pressure becomes maximum reaches a predetermined position at which the engine generated torque becomes maximum. At the same time, knocking is detected by passing a signal for detecting in-cylinder pressure through a signal processing circuit, and when the knocking level exceeds a predetermined value, the ignition timing is retarded to avoid knocking with priority over MBT control. Control.

This intends to improve the driving performance by controlling the knocking and increasing the torque generated by the engine as much as possible.

Thus, it is considered that controlling the ignition timing to suppress knocking is widely adopted because it is easy to control the ignition timing.

(Problems to be solved by the invention) However, in the above device, in order to suppress knocking, the ignition timing that is originally set to the timing at which the combustion state is maximized that maximizes the torque generated by the engine is suppressed. Since the ignition timing is retarded, the combustion state deteriorates due to the ignition timing retard, and the best combustion state cannot be obtained under each operating condition. Therefore, fuel consumption is significantly deteriorated by such deterioration of the combustion state. In addition, the exhaust temperature may rise due to the deterioration of the combustion state, and the durability of exhaust system members such as an exhaust purification catalyst and an exhaust pipe may decrease.

(Object of the invention) Therefore, the present invention is to control the intake air amount, MBT of the ignition timing.
By appropriately selecting the control and the retard control of the ignition timing, the torque /
The purpose of the present invention is to improve the fuel economy and the durability of the engine by keeping the ignition timing at the fuel economy best point (MBT) so that the output torque is maximized while minimizing the deterioration of the acceleration feeling.

(Means for Solving the Problem) For the above purpose, the knocking control device for an internal combustion engine according to the present invention has a pressure detecting means a for detecting the combustion pressure of the engine, as shown in the basic conceptual diagram of FIG. Knock detecting means b for detecting the knocking level of the engine, operating state detecting means c for detecting the operating state of the engine, determining means d for determining the occurrence of knocking when the knocking level exceeds a predetermined level, and knocking for the predetermined knocking level. A first calculation means e for calculating a control value for controlling the intake air amount so as to suppress the level to a level, and a second calculation means f for calculating a control value for controlling the ignition timing so as to suppress the knocking at a predetermined level. The combustion peak position at which the combustion pressure becomes maximum is detected based on the output of the pressure detection means a, and this combustion peak position maximizes the torque generated by the engine. Third computing means g for computing a control value for controlling the ignition timing so as to obtain a target peak position, and the first computing means when the engine is operating in a steady state and knocking occurs. When the output of e is selected, the output of the third computing means g is selected when the engine is in the steady operation and no knocking occurs, the output of the third computing means g is selected, and when the engine is in the acceleration operation and the knocking occurs, A selection means h for selecting the output of the second calculation means f, and an intake air amount that changes the intake air quantity based on the output of the first calculation means e when the selection means h selects the first calculation means e. Operation means i and the selection means h
When the second calculating means f is selected by, the mixture is ignited based on the output of the second calculating means f, and when the third calculating means g is selected by the selecting means h, the third calculating means is selected. Ignition means j for igniting the air-fuel mixture based on the output of g
And are equipped with.

(Operation) Knocking during steady operation is suppressed by controlling the intake air amount regardless of ignition timing, and after this suppression, ignition timing is MBT controlled. On the other hand, knocking during acceleration is suppressed by ignition timing control (retard control) regardless of the intake air amount.

Therefore, the ignition timing is maintained at the fuel efficiency best point (MBT), and further reduction of torque / acceleration feeling is suppressed to the minimum, so that the fuel consumption and the driving performance are improved, and the durability of the engine is improved. To be

(Example) Hereinafter, the present invention will be described with reference to the drawings.

First Embodiment FIGS. 2 to 9 are views showing a first embodiment of a knocking control system for an internal combustion engine according to the present invention.

First, the configuration will be described. In FIG. 2, reference numeral 1 denotes an engine, the intake air amount is supplied from an air cleaner 2 to each cylinder through an intake pipe 3, and fuel is injected by an injector 4 based on an injection signal Si.

A spark plug 5 is attached to each cylinder, and a high voltage pulse Pi from a high voltage generation unit 6 is supplied to the spark plug 5. The ignition plug 5 and the high-pressure generation unit 6 constitute an ignition means 7 for igniting the air-fuel mixture, and the ignition means 7 generates a high-voltage pulse Pi based on the ignition signal Sp and discharges it. Then, the air-fuel mixture in the cylinder is ignited, exploded, and exhausted by the discharge of the high-pressure pulse Pi.

The flow rate Qa of the intake air is detected by the air flow meter 8 and controlled by the throttle valve 9 in the intake pipe 3. The throttle valve 9 is opened and closed by a throttle valve drive unit (intake air amount operating means) 10, and the throttle valve drive unit 10 is, for example, a step motor,
The throttle valve 9 is opened and closed based on the drive signal Sc, which is composed of an angle sensor or the like.

Further, the accelerator opening θa is detected by the accelerator sensor 11, and the crank angle of the engine 1 is determined by the crank angle sensor 12.
Detected by. The crank angle sensor 12 has an explosion interval (6
(120 ° for cylinder engines, 180 ° for 4-cylinder engines)
The reference signal Ca which becomes a pulse of [H] level at a predetermined position before the compression top dead center (TDC) of the angular cylinder, for example, BTDC 70 ° is output every time, and [ [H] level pulse unit signal C ₁
Is output. The engine speed Ne can be known by counting the pulses of the signal Ca. The air flow meter 8 and the crank angle sensor 12 form an operating state detecting means 13.

Further, the load of the engine 1 is detected by the load sensor 14, and the cylinder discrimination is detected by the cylinder discrimination sensor 15.
The load sensor 14 is composed of, for example, a throttle valve opening sensor or an intake pipe negative pressure sensor, and outputs a load signal S _L according to the load state. The cylinder discrimination sensor 15 detects a cylinder discrimination signal S at a predetermined crank angle position (for example, BTDC80 ° of the first cylinder) before compression top dead center of a specific cylinder (for example, the first cylinder).
Output _K. Therefore, the cylinder discrimination signal S _K is output once every two rotations of the crankshaft.

Further, the combustion pressure Pa of the engine 1 is detected by a pressure sensor (pressure detection means) 16, and the pressure sensor 16 is screwed to a cylinder head 17 as shown in FIGS. 3 (A) and 3 (B). Is formed as a washer of the ignition plug 5, and is pressed and fixed in the outer recess of the cylinder head 17 by the tightening portion 5a of the ignition plug 5. Then, a pressure signal Pa corresponding to the pressure in the combustion chamber of the engine (cylinder pressure) is output via a charge amplifier (not shown).

The output of the pressure sensor 16 is input to the knocking detection circuit 18, and the knocking detection circuit 18 detects the occurrence of knocking from the pressure signal Pa (see FIG. 5A) from the pressure sensor 16 as shown in FIG. 4, for example. Especially included a lot 6
A band-pass filter (BPF) 18a that passes only the high frequency component Pa '(see FIG. 5B) of -15 kHz, and half-wave rectifies the high frequency component Pa' and forms an envelope signal from the half-wave rectified signal. (Envelope detection)
The waveform shaping circuit 18b outputs a knocking signal _SN corresponding to the knocking level as shown in FIG. 5C.

In this knocking detection circuit 18, the pressure signal P
Alternatively, a may be smoothed to form a background level corresponding to the normal noise level of the engine, and the difference between the formed level and the maximum level of the envelope signal may be output as the knocking signal S _N.

The pressure sensor 16 and the knocking detection circuit 18 constitute knock detection means 19, and signals from the knock detection means 19 and the sensors 8, 11, 12, 14, 15 are input to the control unit 20.

The control unit 20 has functions as a judging means, first to third calculating means and a selecting means, and as shown in detail in FIG. 6, a CPU 21, a ROM 22, a RAM 23, an NVM (nonvolatile memory) 24 and an input / output interface. , A register, a counter, an A / D converter, a high-frequency cut filter, and the like. CPU
Reference numeral 21 denotes knock suppression, throttle valve opening degree control, and the like while fetching external data required by the input / output control circuit 25 in accordance with a program written in the ROM 22 and exchanging data with the RAM 23 and the NVM 24. The processing value necessary for ignition timing control is arithmetically processed, and the processed data is output to the input / output control circuit 25 as needed. The input / output control circuit 25 receives signals from the sensor groups 8, 11, 12, 14, 15, the operating state detection means 13 and the knocking detection circuit 18, and the input / output control circuit 25 outputs the drive signal Sc and The ignition signal Sp is output. ROM22 is CP
Stores the calculation program in U21, RAM23, NV
M24 stores data used for calculation in the form of a map or the like.

The ignition signal Sp is inputted to the ignition means 7, and the high voltage generation unit 6 of the ignition means 7 is composed of an ignition coil 26, a battery 27 and a transistor Q1 as shown in detail in FIG. Turn on Q1
/ OFF control is performed to generate a high voltage Pi on the secondary side of the ignition coil 26, and the high voltage Pi is supplied to the spark plugs 29a to 29f via the distributor 28 to ignite the air-fuel mixture.

Next, the operation will be described.

FIG. 7 is a flow chart showing a program for knock suppression control and MBT control written in the ROM 22, and this program is processed by interruption every time the reference signal Ca is input.

First, at P ₁ , the accelerator opening θa is read from the A / D converted value of the accelerator sensor 11, and at P ₂ , the target throttle valve opening based on the engine speed N and the accelerator opening θa, which are parameters representing the operating state of the engine. Θt = fu
The calculation is performed based on the function form of nc (θa, N). This θt is stored in advance in a table map as a value that provides a smooth acceleration feeling over a wide range of rotations from low speed to high speed rotation, and is obtained by looking up the optimum value in P _2. .

Then, to detect the knocking level KN from knocking signal S _N in P _3, it is determined whether the vehicle from the detection output of the operating condition detecting means ₁₃ at P ₆₁ is accelerating. If it is determined that the vehicle is not accelerating (that is, if the operating state of the engine is in steady operation), the routine proceeds to P ₄ , where knock determination levels KN ₀ and KN are compared. When KN> KN ₀ , it is determined that knocking has occurred, the feedback correction amount Δθt of θt (Δθt is a negative value) is reduced by α at P ₅ , and Δθt−α is set as a new feedback correction amount Δθt. Record. The correction amount α is the minimum change in throttle valve opening required to prevent knocking, and α = func
(Q, N) (where Q = load (amount of intake air or value of θt itself)). Then P
_{In step 6} , θt + Δθt is set as a new throttle valve opening operation value at this time, and the drive signal Sc corresponding to this is output. That is, when the engine operating condition is steady operation (NO command of P ₆₁ ) and knocking occurs (YES command of P ₄ ), the manipulated variable of the throttle opening (in other words,
Correct the intake air amount control value) in the decreasing direction.

When KN ≦ KN ₀ , it is determined that knocking has not occurred, and the feedback correction value Δθt of θt is set to β at P _7.
(However, β <α) is large (absolute value is small)
Then, it is determined whether or not the value of Δθt is positive at P ₈ . θ
When the t ≧ 0 proceeds to P ₆ by the process of rule the upper limit of Derutashitati as Δθt = 0 in P ₉ to zero. Also, θt <0
If so, proceed directly to P ₆ . This is because the throttle valve circuit becomes larger than the basic value of θt when Δθt> 0.

Next, at P ₁₀ , the MBT control value of the ignition timing is calculated (details will be described later in a subroutine), and at P ₁₁ , the ignition signal Sp is output at the ignition timing corresponding to this control value. That is, the engine operating condition is steady operation (NO command of P ₆₁ )
And knocking does not occur (N in P ₄
When the O command is issued, the operation amount of the throttle valve opening (in other words, the control value of the intake air amount) is corrected in the increasing direction, and then the MBT control is performed. Meanwhile, when the vehicle has a determination accelerating (i.e. determines that the engine is in acceleration operation) in P ₆₁ compares the knock determination level KN ₀ knocking level KN at P _62. When KN ≦ KN ₀ , it is determined that knocking has not occurred, and the process directly proceeds to P ₁₀ to execute the above MBT control, but when KN> KN ₀ , it is determined that knocking has occurred, and P _{At 63} , the feedback correction amount FB of the ignition timing is reduced by the retard correction amount c. However, c is the retard correction amount a of the MBT control described above.
Value greater than (c> a). Then, the process proceeds to the final ignition timing A in P ₆₄ to P ₁₁ calculates according to the following equation.

A = B ₀ + FB, where B ₀ : basic ignition timing, that is, the engine operating state is accelerated (YES in P ₆₁ )
Command) and knocking has not occurred (P
₆₂ NO instruction) when, the process proceeds to MBT control, when knocking is occurring (YES instruction P _62), the process moves to retard control of the ignition timing. Therefore, according to the present embodiment, when knocking occurs during steady operation, the throttle valve opening is moved slightly in the closing direction even if the accelerator depression amount is constant, and if knocking does not occur, the basic value θt is returned and the MBT Take control. That is, the knock suppression process during steady operation is performed only by the operation of the intake air amount, and the ignition timing is not used for the knock suppression process during steady operation, but can be changed by the MBT control. Therefore, knock can be suppressed while maintaining the ignition timing at MBT, and unlike the conventional case, the combustion state during steady operation can be optimally maintained.

As a result, it is possible to improve fuel efficiency, suppress an excessive rise in exhaust temperature, and prevent deterioration of durability of exhaust members such as an exhaust catalyst and an exhaust pipe. Regarding the fuel consumption, the fuel consumption at high speed is greatly improved compared with only the method of avoiding knocking by retarding the ignition timing.

Furthermore, in the present embodiment, the operating state (whether or not the acceleration condition, etc.)
Is selected and the knock suppression mode is selected from throttle valve opening control (intake air amount control) or ignition timing control, whichever is the most advantageous. Therefore, the decrease in acceleration feeling during acceleration is minimized. The effect that it can be suppressed to the limit is also obtained.

That is, in the steady state, the throttle valve opening control is adopted as described above, but during the acceleration, the ignition timing control is adopted to retard the ignition timing when knocking occurs to suppress knocking and knocking must occur. If the knocking is suppressed, the ignition timing is set to MBT.
To maintain fuel economy and improve fuel efficiency.

As described above, in this embodiment, since the knock suppression mode is selected depending on the operating state, the fuel consumption can be improved by suppressing the knock by controlling the throttle opening, and the retard control of the ignition timing can be used to charge the fuel particularly during rapid acceleration. There is no reduction in efficiency and the acceleration feeling is greatly improved.

Here, the MBT control of the ignition timing corresponding to the steps P ₁₀ and P ₁₁ will be described in detail.

The MBT control is performed by the crank angle θ of the maximum value P _max of the cylinder pressure.
Minimum Ad when _pmax (see FIG. 5 (a)) is at a predetermined value (eg 15 ° to 20 ° ATDC) after compression top dead center.
The ignition timing of vance for Best Torque (MBT) is given, and feedback control is performed so that θ _pmax becomes the above predetermined value. That is, the eighth in the subroutine shown in FIG., First predetermined crank angle a cylinder pressure signal Pa at P _21, for example, the maximum value A / D conversion for each 2 ° P
_max is calculated, and then the crank angle at the time of calculating P _max in P ₂₂ is calculated as θ _pmax , and this is stored.

FIG. 9 shows an MBT control subroutine.

First, the basic ignition timing from the engine load Q and the engine speed N in P ₃₁ (omitted correction amount of the engine coolant temperature)
B ₀ is obtained according to the functional form of B ₀ = func (Q, N), and θ of this time obtained by the subroutine of FIG. 7 at P ₃
Determine the position of _pmax .

When θ _pmax is within the predetermined range given to MBT, the final ignition timing A is calculated according to the following equation at P ₃₃ .

A = B ₀ + FB, where FB: feedback correction amount of ignition timing On the other hand, when θ _pmax is on the lag side with respect to the predetermined range giving MBT, the previous feedback correction amount F at P ₃₄
The advance correction amount a is added to B, and FB + a is added to the new correction amount FB.
And proceed to P ₃₃ . When θ _pmax is on the advance side, the retard correction amount b is subtracted from the feedback correction amount FB at P ₃₅ , and FB-b is set as a new correction amount FB, and the process proceeds to P ₃₃ .

Second Embodiment FIG. 10 is a diagram showing a second embodiment of the present invention. The same steps as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the present embodiment, the first embodiment is performed in that steps P ₁₀ and P ₁₁ (MBT control processing) are performed during steady operation regardless of whether knocking is present or during acceleration operation without knocking. Different from the example. Therefore, in the second embodiment, since the intake air amount control and the MBT control are used together even in the steady operation with knocking, there is an advantage that the control stability is improved.

Third Embodiment FIGS. 11 to 13 are views showing a third embodiment of the present invention.

In this embodiment, the supercharging pressure is controlled by the opening degree of the swing valve as a method for controlling the intake air amount. That is, the supercharging pressure control for knocking control is added to the original control of the VN turbo.

In FIG. 11, 41 is an intake pipe, and the intake pipe 41 is provided with a compressor 42a of an exhaust turbocharger 42,
The compressor 42a is a turbine 42b arranged in the exhaust pipe 43.
Connected to. The exhaust turbo supercharger 42 drives the turbine 42b by the exhaust gas, and supercharges the intake air by the compressor 42a which is interlocked with the turbine 42b. The flow rate of the exhaust gas passing through the turbine 42b is controlled by a variable nozzle 44 and a swing valve 45 composed of a wastegate valve, and the variable nozzle 44 and the swing valve 45 each have a control signal S having a duty value.
_The supercharging pressure is controlled by adjusting the pressure applied to the turbine 42b based on _K1 and S _K2 . In addition, the variable nozzle 44 is PCM (Pr
essure Control Modulator) driven by valve 46,
The swing valve 45 is driven by the PCM valve 47.
The PCM valves 46, 47 together constitute an intake air amount operating means 48 for operating the supply of intake air.

In the above-mentioned configuration, FIG. 12 is a flowchart showing a program for knock suppression control and boost pressure control in this embodiment.

First, the variable nozzle 44 is controlled at P ₄₁ , and P at this time is controlled.
The duty of the CM valve 46 is D ₁ . Here, the variable nozzle control is to provide a flap on the turbine nozzle portion of the exhaust turbocharger 42 to control the nozzle area according to the operating state, and particularly torque and response are improved in the low speed range.

Next, the original swing valve 45 determined by the intake air amount is controlled at P ₄₂ , and the duty of the PCM valve 47 at this time is set to D ₂ . Knocking level KN on P ₄₃
Detects, determines whether the vehicle in P ₇₃ meets the accelerated conditions. Then, the process proceeds to P ₇₄ if accelerated conditions,
If not accelerated conditions, i.e. proceeds directly to P ₄₄ If the time of steady state operation. In P ₄₄ the knocking level KN
Is compared with a predetermined knock determination reference level KN _0, and KN>
When KN ₀ , it is judged that knocking has occurred, and P
_In order to correct the duty D ₂ in the opening direction of the swing valve 45 at ₄₅ , the correction amount ΔD ₂ for correcting this D ₂ is reduced by d ₁ . ΔD ₂ is a negative value, and the absolute value | ΔD ₂
| Tends to increase. Then, at P ₄₆ , D ₂ + ΔD
₂ as a control duty _{D 2} new PCM valve M47 in the current, and outputs a control signal S _K2 having the duty _{D 2} at P _47, the step P ₄₁ in P ₄₈
The control signal S _K1 having the duty D ₁ in is output. Here, steps P _{41 to} P ₄₈ collectively constitute the first computing means.

Then, after P ₄₈ , the MBT control value of the ignition timing is calculated at P ₇₁ , and the ignition signal Sp is calculated at P ₇₂ at the ignition timing corresponding to the final ignition timing A during steady operation (see P _{33 in} FIG. 9).
Is output. The final ignition timing A during acceleration operation
Is given at P ₇₉ , as described below.

When acceleration operation (YES instruction P ₇₃₎ detects the boost pressure at P _74, the supercharging equal to or greater than a predetermined value is determined to be sufficiently P
Proceeds to _44, when the boost pressure is less than a predetermined value, the process proceeds to P ₇₅ to priority to increase the intake charging efficiency. That is,
Ignition timing retard control (corresponding to the second computing means) is adopted for knock control. In P ₇₅ compares the knocking level KN knock determination level KN _0. When KN> KN ₀ , it is determined that knocking has occurred, and the feedback correction amount FB of the ignition timing is reduced by the retardation correction amount c at P ₇₆ . Next, at P ₇₇ , it is determined whether or not the feedback correction amount FB is smaller than the predetermined correction amount FB ₁ , and FB ≦ FB
When it is ₁ , P ₇₈ sets FB = FB ₁ and then proceeds to P _79.
When B ≦ FB ₁ is not satisfied, the program proceeds to P ₇₉ as it is, the final ignition timing A is calculated according to the following equation, and the program proceeds to P ₇₂ .

A = B ₀ + FB, where B ₀ : basic ignition timing Further, when KN ≦ KN _{0 in} P ₇₅ above, it is determined that knocking has not occurred, and in P ₈₀ the feedback correction amount F
B is increased by the advance correction amount a (however, a <c). Next, at P ₈₁ , it is determined whether or not the feedback correction amount FB is larger than a predetermined correction amount FB ₂ (however, FB ≦ FB ₂ ), and when FB ≧ FB ₂ , FB = FB ₂ at P ₈₂ and P
Proceed to ₇₉ . In the steps of P ₇₇ , P ₇₈ , P ₈₁ and P ₈₂ , the range of the feedback correction amount FB is FB ₁ ≦ FB ≦
Limit processing for setting FB ₂ (here, FB is a value with plus and minus signs) is performed.

On the other hand, it is determined that knocking when the KN ≦ KN ₀ in step P ₄₄ has not occurred, the swing valve at P ₄₉
Since the duty D ₂ is corrected in the closing direction of 45, the correction amount D
₂ is increased by d ₂ (however, d ₂ <d ₁ ). Then, it is determined whether or not the value of the correction amount [Delta] D ₂ at P ₅₀ is positive, when the [Delta] D ₂ ≧ 0 proceeds to P ₂₉ as [Delta] D ₂ = 0 at P _51, it is when the [Delta] D ₂ <0 proceed to the P _29. Thereby, the limit process of ΔD ₂ is performed.

By the above steps of P ₄₁ to P _51, region by knock control as indicated by the shaded portion of FIG. 13 in the control area of the PCM valve 47 is applied. The upper limit of this region is the maximum torque characteristic determined by the original control of the PCM valves 46 and 47, but the lower limit changes depending on how knocking occurs (for example, environmental conditions of the engine, dependence of fuel used, etc.).

Therefore, in the present embodiment, the intake air amount can be controlled by the opening of the swing valve to suppress the occurrence of knocking, and the fuel consumption can be significantly improved as compared with the method of avoiding knocking only by controlling the ignition timing.

Further, in this embodiment, since the knock control mode is selected depending on the operating state (whether or not the acceleration condition is satisfied), knock suppression by intake air amount control and improvement of fuel efficiency can be achieved by MBT control. By performing knock suppression by retarding the timing, it is possible to obtain an effect that the charging efficiency does not decrease even during sudden acceleration and the acceleration feeling is significantly improved.

Note that, in the present invention, if the mode in which knocking is suppressed is performed for each cylinder, it is not necessary to control the intake air amount and retard the ignition timing for cylinders in which knocking has not occurred, and to improve fuel efficiency and output. It is also advantageous in terms of.

(Effect) According to the present invention, the intake air amount control, the ignition timing MBT
Since the control and the retard control of the ignition timing are appropriately selected, it is possible to appropriately prevent the occurrence of knocking and minimize the decrease in the torque / acceleration feeling, and always maintain the best combustion state. As a result, it is possible to significantly improve fuel economy and driving performance and improve durability of the engine.

[Brief description of drawings]

FIG. 1 is a basic conceptual diagram of the present invention. 2 to 9 are diagrams showing a first embodiment of a knocking control device for an internal combustion engine according to the present invention, FIG. 2 is an overall configuration diagram thereof, and FIG. 3 is a sectional view and a plan view of a pressure sensor thereof. FIG. 4 is a block configuration diagram of the knock detection circuit, FIG. 5 is a waveform diagram of the knock detection circuit, FIG. 6 is a configuration diagram of the control unit, and FIG. 7 is the knock control, throttle valve opening control and FIG. 8 is a flow chart showing a program for ignition timing control, FIG. 8 is a flow chart showing a program for obtaining a crank angle when the cylinder pressure is maximum, and FIG. 9 is a flow chart showing a program for MBT control. FIG. 10 is a flowchart showing a program for knock control, throttle valve opening control, and ignition timing control showing a second embodiment of a knocking control device for an internal combustion engine according to the present invention. 11 to 13
FIG. 3 shows a third knocking control device for an internal combustion engine according to the present invention.
FIG. 11 is a diagram showing an embodiment, FIG. 11 is its overall configuration diagram, FIG.
FIG. 13 is a flow chart showing a program for the knock control, supercharging pressure control and ignition timing control, and FIG. 13 is a view showing a swing valve control region by the knock control in a relation between shaft torque and engine speed. 1 ... Engine, 7 ... Ignition means, 10 ... Throttle valve drive unit (intake amount operation means), 13 ... Operating state detection means, 16 ... Pressure sensor (pressure detection means), 19 ... Knock detection means , 20 ... Control unit (determination means, first calculation means, second calculation means, third calculation means, selection means) 48 ... Intake amount operation means.

Claims (1)

[Claims] 1. A) pressure detecting means for detecting combustion pressure of the engine, b) knock detecting means for detecting knocking level of the engine, c) operating state detecting means for detecting operating state of the engine, and d). Determination means for determining occurrence of knocking when the knocking level exceeds a predetermined level; e) first calculation means for calculating a control value for controlling the intake air amount so as to suppress knocking to a predetermined level; f) knocking Second calculation means for calculating a control value for controlling the ignition timing so as to suppress the combustion timing to a predetermined level, and g) a combustion peak position where the combustion pressure becomes maximum based on the output of the pressure detection means, and this combustion is performed. Third calculation of a control value for controlling the ignition timing so that the peak position becomes a target peak position that maximizes the torque generated by the engine
Computing means, and h) when the engine operating state is steady operation and knocking has occurred, the output of the first computing means is selected to be steady operation and knocking has not occurred. When the output of the third calculating means is selected, the selecting means selects the output of the second calculating means when the engine is in acceleration operation and knocking is occurring, and i) by the selecting means. An intake air amount operation means for changing the intake air amount based on the output of the first operation means when one operation means is selected, and j) the second operation when the second operation means is selected by the selection means. Ignition means for igniting the air-fuel mixture based on the output of the third arithmetic means when the third arithmetic means is selected by the selecting means, while igniting the air-fuel mixture based on the output of the means. Characteristic of internal combustion engine Knocking control device.