WO2018198567A1

WO2018198567A1 - Ignition control device for internal-combustion engine

Info

Publication number: WO2018198567A1
Application number: PCT/JP2018/010157
Authority: WO
Inventors: 一浩押領司; 赤城　好彦
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2017-04-25
Filing date: 2018-03-15
Publication date: 2018-11-01
Also published as: JP2018184862A; JP6764824B2

Abstract

The objective of the present invention is to provide an ignition control device for an internal-combustion engine capable of predicting the occurrence of knocking resulting from a temperature change in an uncombusted region, and capable of suppressing knocking effectively in a combustion cycle in which knocking has been predicted. To this end, the ignition control device is provided with a knocking occurrence predicting unit 27 which predicts knocking on the basis of a change in a cooling loss of an internal-combustion engine, calculated on the basis of a signal from a cylinder pressure sensor 26 attached to a combustion chamber, and is additionally provided with a knocking control unit 28 which controls an ignition period of the internal-combustion engine on the basis of detected information correlated to the cooling loss detected by the knocking occurrence predicting unit. Knocking resulting from a wall temperature increase accompanying an increase in cooling loss, and a concomitant temperature increase in the uncombusted region is predicted, and retardation control of the ignition period is performed in the combustion cycle in which knocking has been predicted, making it possible for knocking to be effectively suppressed.

Description

Ignition control device for internal combustion engine

The present invention relates to an ignition control device for an internal combustion engine, and more particularly to an ignition control device for a fuel engine that controls ignition timing using an in-cylinder pressure sensor.

In recent years, in vehicles such as automobiles, regulations on fuel consumption (fuel consumption) and exhaust gas harmful components have been strengthened, and such regulations tend to be strengthened in the future. In particular, regulations related to fuel consumption are of great interest due to problems such as recent increases in fuel prices, impacts on global warming, and depletion of energy resources.

Under such circumstances, in the automobile industry, for example, various technological developments are being promoted for the purpose of improving the fuel efficiency performance and exhaust gas purification performance of the vehicle. As one of the development technologies aimed at improving the fuel consumption performance, for example, a high compression ratio technology for increasing the compression ratio of an internal combustion engine is known. In addition, as one of the development technologies aimed at improving the exhaust gas purification performance, for example, fuel is injected in multiple times during the intake stroke, and the fuel injection amount per time is reduced to reduce PN (Particulate Number) A multistage injection technique for reducing the above is known.

In the above-described high compression ratio technology, it is known that when the compression ratio of the internal combustion engine is increased, thermal efficiency is improved and fuel efficiency is improved, but the temperature in the combustion chamber is increased and knocking is likely to occur.
For this reason, in a conventional internal combustion engine, by utilizing the fact that a specific frequency signal level rises when knocking occurs, a vibration type knock sensor is attached to the cylinder block, and a predetermined crank period (knock window) output from the knock sensor. Is detected by FFT (Fast Fourier Transform) analysis, and the ignition timing is retarded after the occurrence of the knock based on the knock detection information, thereby avoiding the subsequent occurrence of the knock. Yes.

By the way, for the occurrence of knock, it is considered effective to predict a combustion cycle in which knock occurs in advance from the combustion state and to retard the ignition timing in this combustion cycle.
In relation to this, the optimum ignition timing that changes according to the operating condition is calculated as a combustion state parameter whose value is determined for each combustion cycle according to the relationship between the in-cylinder pressure and the crank angle. A technique for improving the knock avoidance performance by optimizing the combustion state so as to realize the state parameter is known.

For example, Japanese Unexamined Patent Application Publication No. 2014-136972 (Patent Document 1) discloses a method for suppressing an amount of change in a specific combustion ratio point (crank angle at which combustion progresses to a predetermined combustion state) that changes for each cycle. Techniques for stabilizing the engine output are shown. This technique is effective as a method for controlling the ignition timing in a state where the air-fuel mixture is in excess of air or in a state where combustion is unstable in a state diluted with exhaust gas recirculation (EGR).

JP 2014-136972 A

However, in Patent Document 1, apart from the progress of combustion due to the flame propagation starting from the spark discharge by the spark plug, the abnormality that occurs from the self-ignition that occurs in the region where the flame has not yet reached (unburned region) With respect to the change in the combustion state caused by the occurrence of knock that is combustion, the assumed combustion change factor is different, which may promote the occurrence of knock.

An object of the present invention is to provide an ignition control device for an internal combustion engine that can predict the occurrence of knock due to a temperature change in an unburned region and can effectively suppress the knock in a combustion cycle in which the occurrence of knock is predicted. There is.

A feature of the present invention is that it includes a knock generation prediction unit that predicts the occurrence of knock based on a change in cooling loss (wall temperature change) of the internal combustion engine calculated based on a signal from an in-cylinder pressure sensor attached to the combustion chamber. A knock control unit that controls the ignition timing of the internal combustion engine based on knock prediction information related to the cooling loss detected by the occurrence prediction unit is provided.

According to the present invention, the occurrence of knock due to the increase in wall temperature accompanying the increase in cooling loss and the accompanying increase in temperature in the unburned region is predicted, and the ignition timing is retarded in the combustion cycle in which the occurrence of knock is predicted. Thus, knock can be effectively suppressed.

1 is an overall configuration diagram showing the overall configuration of an internal combustion engine to which the present invention is applied. It is the block diagram which showed the internal structure of the control apparatus shown in FIG. It is a system block diagram of the control apparatus shown in FIG. It is explanatory drawing explaining a combustion period, a combustion time, and a combustion ratio. It is explanatory drawing explaining a knock intensity | strength. It is a flowchart figure which shows the control step implemented in the knock generation | occurrence | production prediction part which becomes the 1st Embodiment of this invention. It is explanatory drawing explaining the average value and mode value based on the statistical process in the case of no knock. It is explanatory drawing explaining the average value and mode value based on the statistical process in case of knocking. It is a flowchart figure which shows the control step which suppresses a knock using the prediction result of the knock generation | occurrence | production prediction part shown in FIG. It is a flowchart figure which shows the control step of the ignition timing delay angle setting by wall temperature shown in FIG. Knock strength, combustion period, and combustion period average value when the first embodiment of the present invention is implemented. It is explanatory drawing which shows the change of ignition timing. It is a flowchart figure which shows the control step implemented in the knock generation | occurrence | production prediction part which becomes the 2nd Embodiment of this invention. It is explanatory drawing explaining the change of a cylinder pressure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and application examples are included in the technical concept of the present invention. Is also included in the range.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the overall configuration of an internal combustion engine to which the present invention is applied. For example, FIG. 1 shows an automotive four-cylinder internal combustion engine that performs spark ignition combustion using gasoline as a fuel.

The internal combustion engine 100 shown in the drawing is an air flow sensor 1 that measures the amount of intake air, an electronic control throttle 2 that adjusts the pressure of the intake pipe 6, and an intake air temperature detector at an appropriate position of the intake pipe 6. An intake air temperature sensor 15 for measuring the intake air temperature and an intake air pressure sensor 21 for measuring the pressure in the intake pipe 6 are provided.

The internal combustion engine 100 also includes a fuel injection device (in-cylinder direct injection injector or simply an injector for direct injection) for each cylinder (# 1 to # 4) communicating with each intake pipe 6 into the combustion chamber 12 of each cylinder. 3), an ignition system 4 that supplies ignition energy, and an in-cylinder pressure sensor 26 that detects in-cylinder pressure.

In addition, the internal combustion engine 100 includes a cooling water temperature sensor 14 that measures the cooling water temperature of the internal combustion engine 100 at an appropriate position of the cylinder head 7, and an intake valve variable device 5a that adjusts the intake gas flowing into the cylinder. And an exhaust valve variable device 5b for adjusting the exhaust gas discharged from the cylinder. Here, the variable valve 5 has a phase angle sensor (not shown) for detecting the phase angle of the intake valve variable device 5a and the exhaust valve variable device 5b. By adjusting the phase angle of the device 5a and the exhaust valve variable device 5b), the intake amount and EGR amount of all cylinders from # 1 to # 4 can be adjusted.

A high pressure fuel pump 17 for supplying high pressure fuel to the fuel injection device 3 is connected to the fuel injection device 3 of the internal combustion engine 100 via a fuel pipe, and the fuel pressure is measured in the fuel pipe. A fuel pressure sensor 18 is provided, a crankshaft (not shown) of the internal combustion engine 100 is provided with a crank angle sensor 13 for calculating its rotation angle, and a cylinder block (not shown) of the internal combustion engine 100 is provided. ) Is provided with a knock sensor 25 for detecting the vibration of the internal combustion engine 100.

Further, the internal combustion engine 100 detects the air-fuel ratio of the exhaust gas at an appropriate position of the exhaust pipe 8 and a three-way catalyst 10 that purifies the exhaust and an aspect of an air-fuel ratio detector that is upstream of the three-way catalyst 10. And an exhaust gas temperature sensor 11 that measures the exhaust gas temperature upstream of the three-way catalyst 10 in one mode of the exhaust gas temperature detector.

The internal combustion engine 100 includes an engine control unit (hereinafter referred to as ECU) 20 that is a control means for controlling the combustion state of the internal combustion engine 100, and the air flow sensor 1, the air-fuel ratio sensor 9, and the cooling water temperature sensor described above. 14, intake temperature sensor 15, exhaust temperature sensor 11, crank angle sensor 13, fuel pressure sensor 18, intake pressure sensor 21, ignition system 4, in-cylinder pressure sensor 26,

variable valve devices

5a and 5b, knock sensor 25, and the like. A signal is transmitted to the ECU 20. The ECU 20 is also transmitted with a signal obtained from an accelerator opening sensor 16 that detects the amount of depression of the accelerator pedal, that is, the accelerator opening.

The ECU 20 calculates a required torque for the internal combustion engine 100 based on a signal obtained from the accelerator opening sensor 16. Further, the ECU 20 calculates the rotational speed of the internal combustion engine 100 based on a signal obtained from the crank angle sensor 13. Further, the ECU 20 calculates the operating state of the internal combustion engine 100 based on signals obtained from the outputs of the various sensors described above, as well as air flow rate, fuel injection amount, ignition timing, throttle opening, variable valve operating amount, fuel A main operation amount related to the internal combustion engine 100 such as pressure is calculated.

The fuel injection amount calculated by the ECU 20 is converted into a valve opening pulse signal and transmitted to the fuel injection device 3. Further, an ignition signal generated so as to be ignited at the ignition timing calculated by the ECU 20 is transmitted from the ECU 20 to the ignition system 4. Further, the throttle opening calculated by the ECU 20 is transmitted to the electronic control throttle 2 as a throttle drive signal, the operation amount of the variable valve is transmitted to the valve

variable devices

5a and 5b as a variable valve drive signal, and the fuel pressure is It is transmitted to the high pressure fuel pump 17 as a high pressure fuel pump drive signal.

Based on the valve opening pulse signal transmitted from the ECU 20 to the fuel injection device 3, a predetermined amount of fuel is supplied from the fuel injection device 3 to the air flowing into the combustion chamber 12 from the intake pipe 6 via the intake valve (not shown). Is injected to form an air-fuel mixture. The air-fuel mixture formed in the combustion chamber 12 is exploded by a spark generated from the spark plug 4a (see FIG. 2) of the ignition system 4 at a predetermined ignition timing based on the ignition signal, and the combustion pressure causes a piston (not The driving force of the internal combustion engine 100 is generated by being pushed down. The exhaust gas after the explosion is sent to the three-way catalyst 10 through the exhaust pipe 8, and the exhaust components of the exhaust gas are purified in the three-way catalyst 10 and discharged to the outside.

FIG. 2 shows the internal configuration of the ECU 20 shown in FIG. The illustrated ECU 20 mainly includes an input circuit 20a, an input / output port 20b made up of an input port and an output port, a ROM 20d in which a control program describing the contents of arithmetic processing is stored, and a CPU 20e for arithmetic processing according to the control program. And a RAM 20c that stores a value indicating the operation amount of each actuator calculated according to the control program, and an ignition output circuit 20f that controls the spark plug based on a value indicating the operation amount of the spark plug.

As shown in the figure, an input circuit 20a of the ECU 20 includes an air flow sensor 1, an ignition system 4, an air-fuel ratio sensor 9, an exhaust gas temperature sensor 11, a crank angle sensor 13, a coolant temperature sensor 14, an intake air temperature sensor 15, an accelerator opening. Output signals from the sensor 16, the fuel pressure sensor 18, the intake pressure sensor 21, the in-cylinder pressure sensor 26, the knock sensor 25, and the like are input. The input signal input to the input circuit 20a is not limited to these. The input signal of each sensor input to the input circuit 20a is transmitted to the input port in the input / output port 20b, stored in the RAM 20c, and then processed by the CPU 20e according to a control program stored in the ROM 20d in advance.

A value indicating the operation amount of each actuator calculated according to the control program by the CPU 20e is stored in the RAM 20c, and then transmitted to the output port in the input / output port 20b, and is transmitted to the ignition system 4 through the ignition output circuit 20f. The In addition, the drive circuit in ECU20 is not limited to this. Moreover, these drive circuits can also be provided outside ECU20.

Here, as described above, the output signal of the in-cylinder pressure sensor 26 is input to the input circuit 20a of the ECU 20, and the ECU 20 stores in advance in the ROM 20d by the CPU 20e based on the input signal (becomes a knock signal). According to the control program, the occurrence of knock or the occurrence of knock in the internal combustion engine 100 is detected. When the ECU 20 detects a knock occurrence sign or a knock occurrence in the internal combustion engine 100, the ECU 20 transmits a control signal to the ignition system 4 via the ignition output circuit 20f to control the ignition timing in the retarded direction.

Next, a method of detecting the occurrence of knocking in the internal combustion engine 100 by the ECU 20 and a method of controlling the ignition timing will be described with reference to FIGS. In addition, since it can be said that the knock sign is also a knock prediction, the following explanation may be synonymous with the sign or the prediction.

FIG. 3 is a diagram showing an outline of the control logic of knock occurrence prediction and knock suppression control executed in the ECU 20 of the ignition control device of the internal combustion engine according to the embodiment of the present invention. The control logic correlates with detection information related to a change in cooling loss radiated from the combustion chamber through the combustion chamber wall surface and knock generation based on at least input information from the crank angle sensor 13 and the in-cylinder pressure sensor 26. A knock occurrence prediction unit 27 that predicts the occurrence of a knock from a statistic (statistic average value, statistic mode value, etc.) and calculates a knock predictor flag; a knock occurrence predictor flag set by the knock occurrence predictor 27; It is comprised from the knock control part 28 which performs the ignition control for suppressing a knock based on the above-mentioned sensor output. The knock occurrence prediction unit 27 and the knock control unit 28 are control function units constructed by the control program of the CPU 20e.

FIG. 4 is a diagram for explaining the specific combustion ratio, the arrival time of the specific combustion ratio, and the combustion period based on these, which are related indicators of cooling loss. The combustion ratio is calculated by calculating the calorific value in the cylinder from the in-cylinder pressure and the in-cylinder volume, integrating the calculated calorific value in the cylinder, and further normalizing this. The calorific value in the cylinder is calculated by the following formula.

Here, Q is a calorific value [J], γ is a specific heat ratio [−], P is a pressure [Pa], V is an in-cylinder volume [m ³ ], and θ is a crank angle [deg].

Next, the integrated heat generation amount Q (θ) at an arbitrary crank angle is calculated by integration from the ignition timing by the spark plug 4a to the arbitrary crank angle θ. Specifically, the following formula is used.

Here, θADV is the crank angle [deg] of the ignition timing.

Furthermore, the total calorific value Q (total) is calculated by setting an appropriate integration completion time θEND. Specifically, the following formula is used.

Further, normalization of the heat generation amount is calculated by a ratio (Q (θ) / Q (total)) of the total heat generation amount Q (θ) and the total heat generation amount Q (total) at an arbitrary crank angle. This is expressed as a combustion ratio MFB (θ). Further, the combustion phase, which is one of the indexes indicating the combustion state, is defined as the crank angle at which the combustion ratio MFB (θ) has reached a specific value (specific combustion ratio point). In the following description, the combustion phase and the combustion period are exemplarily defined as values using a crank angle at which the combustion ratio reaches 10% and a crank angle at which the combustion ratio reaches 90%.

Here, as the combustion phase, the crank angle timing at which the combustion rate reaches 10% is referred to as MFB10, and the crank angle timing at which the combustion rate reaches 90% is referred to as MFB90. Furthermore, as the combustion period, a combustion period IG90 that is a crank angle period from the start of ignition to MFB90 and a combustion period MFB1090 that is a crank angle period from MFB10 to MFB90 can be defined.

In this embodiment, since the entire combustion period can be handled by selecting the combustion period IG90, the correlation with the cooling loss is stronger than that in the combustion period MFB1090. It is also possible to select the combustion period MFB1090. In this case, by selecting the MFB1090, the combustion change caused by the ignition can be removed and the examination can be made, so that the conditions with different ignition timings are arranged as the same condition. Can do.

When the combustion period IG90 is short and combustion is completed quickly, the maximum temperature in the cylinder becomes high, and the residence time of the high-temperature combustion gas in the cylinder becomes long, so that the cooling loss (heat loss from the wall of the combustion chamber) ) Increases, and the wall surface temperature of the combustion chamber increases. In order to determine the change tendency of the cooling loss, it is important to grasp how the entire combustion period changes for each combustion cycle. For this purpose, the combustion period IG90, the combustion period MFB1090, and the combustion ratio A change in cooling loss can be estimated using the MFB 90.

However, as the combustion timing and the combustion period, there are a plurality of periods such as MFB50 which have a correlation with the change of the cooling loss, and also vary depending on the internal combustion engine, and can be replaced with these indexes.

FIG. 5 is a diagram for defining the knock strength for determining the presence or absence of knock based on the detection value of the in-cylinder pressure sensor. FIG. 5 shows the result of extracting the high-frequency component of the detected in-cylinder pressure as an absolute value. Here, the maximum value of the absolute value of the pressure high-frequency component is defined as the knock intensity, and the presence / absence of knock occurrence is determined. However, the presence or absence of knocking can be detected using a plurality of detection methods even when the in-cylinder pressure sensor 26 is used, and detection using the knock sensor 25 is also possible. Other than the method shown in FIG. For example, the knock intensity can be defined based on the power spectrum obtained by processing the detected value of the knock sensor by FFT.

Next, calculation processing performed by the knock occurrence prediction unit 27 shown in FIG. 3 will be described with reference to FIG. The control flow shown in FIG. 6 predicts knocking by statistically processing parameters such as the combustion period IG90, the combustion period MFB1090, and the combustion ratio MFB90 shown in FIG.

<< Step S61 >> First, in step S61, the combustion ratio MFB (θ) is calculated. The combustion ratio MFB (θ) can be calculated based on the equations shown in the description of FIGS. When the calculation of the combustion ratio MFB (θ) is completed, the process proceeds to step S62.

<< Step S62 >>
In step S62, the statistic of combustion period IG90 (or combustion period MFB1090) is calculated. What is calculated in the calculation of the statistic is a statistical distribution, an average value, a mode value, and a history of a plurality of (predetermined number) combustion cycles of the target combustion period IG90.

The statistical distribution will be described with reference to FIGS. 7A and 7B. FIG. 7A and FIG. 7B show the statistical distribution of the combustion period in FIG. 7A showing operating conditions with no knocking or low knock frequency, and FIG. 7B showing operating conditions with many knocks. A characteristic curve indicated by a solid line is a curve obtained by approximating a statistical distribution with a normal distribution.

Statistic distribution is obtained by grouping for each combustion period and combustion time and arranging the number of appearances of each group as a percentage. For example, a combustion period group is defined every 5 [deg], each group is numbered from 1 to n, and the appearance ratios of the combustion cycles belonging to each group are R1, R2,..., Rn. To do. Here, R1 to Rn are statistical distributions, the combustion period of the group having the largest appearance ratio is the mode value, and the combustion period obtained by arithmetic average is the average value.

In the distribution close to the normal distribution, the mode value and the average value are almost the same, but the mode value and the average value are different when deviating from the normal distribution. In an operating condition where knock does not occur or knock frequency is low, as shown in FIG. 7A, the frequency of occurrence of each combustion period is close to a normal distribution, and the average value and the mode value almost coincide. On the other hand, in the operating condition where the frequency of knocking is high, as shown in FIG. 7B, the mode value shifts to the shorter combustion period side than the average value. The reason why the mode shifts to the shorter combustion period compared to this average value is that the rate of heat generation increases with the occurrence of self-ignition combustion that causes knocking, compared to the case where combustion proceeds by flame propagation, This is because the time until the total heat generation is completed (combustion period) is shortened.

It should be noted that it is appropriate to calculate the statistic by dividing it into a plurality of conditions according to the conditions of the rotational speed of the internal combustion engine and the engine torque. However, by using the combustion period, the ignition timing difference of several degrees (about 1 ° to 3 °) in the crank angle can be handled as the same condition. By calculating the statistic executed in step S62, it is possible to organize the situation for determining whether the current driving condition is a condition where the frequency of knocking is high or a condition where the frequency of knocking is low.

In step S62, the history of the combustion periods IG90 of a plurality of combustion cycles including the current combustion cycle and the combustion period IG90 of the current combustion cycle are calculated as statistics.
The change tendency of the cooling loss can be estimated from the history of a plurality of combustion cycles in the combustion period IG90.

As shown in the explanation of FIG. 4, when the combustion period IG90 is short, the cooling loss is relatively large, and when the combustion period IG90 is long, the fact that the cooling loss is relatively small is used to change the combustion period IG90. Based on this, it is possible to capture the changing tendency of the cooling loss for each combustion cycle.

Here, the increase (decrease) in the cooling loss represents the rise (decrease) in the wall temperature accompanying the increase (decrease) in the wall heat transfer amount. Therefore, an increase (decrease) in the wall temperature means an increase (decrease) in the amount of heat received by the unburned area from the wall surface in the next combustion cycle, and further increases (decreases) the temperature in the unburned area. I mean.

That is, it can be determined that the temperature of the unburned region continuously increases for each combustion cycle under the condition that the combustion period IG90 shows a change that continuously decreases for each combustion cycle. In step S62, by using the statistical distribution of the combustion period IG90 and the history of a plurality of combustion cycles, it is possible to capture the change in cooling loss (temperature of the unburned region) and the occurrence of knock using the same index, and the calculation. Increase in load can be suppressed. After executing the above calculation, the process proceeds to step S63.

<< Step S63 >> In step S63, the knock strength is calculated. The calculation of the knock intensity can be defined from the maximum value of the absolute value of the high-frequency component by taking out the high-frequency component from the detection value of the in-cylinder pressure sensor, as shown in the description of FIGS. By doing in this way, the information which determines the strength of the knock generated based on the output of the cylinder pressure sensor can be obtained. Next, the process proceeds to step S64, where the knock predictor flag is set.

<< Step S64 >> In step S64, a knock predictor flag is set. The knock predictive flag is a flag that is set to “1” (YES) when the probability of occurrence of knocking is high in the next combustion cycle and “0” (NO) when low.

Knock is caused by self-ignition that occurs in the unburned area. Self-ignition occurs when a high-temperature state is maintained through the occurrence of a low-temperature oxidation reaction caused by a temperature increase in the unburned region, or a high-temperature oxidation reaction that occurs when the temperature further increases. In order to estimate the sign of knocking, if the low-temperature oxidation reaction that is one step before knocking can be grasped, and if the temperature rises further in the next combustion cycle, then large-scale autoignition will occur in the next combustion cycle. It can be estimated that there is a high possibility of Here, a knock generation prediction method that assumes a cooling loss and a change in wall temperature and a change in unburned region temperature associated therewith is used.

In step S64, it is determined from the combustion timing IG90 calculated in step S62 or the history of a plurality of combustion cycles in the combustion period whether the possibility of knocking is high in the next combustion cycle. If the temperature of the unburned region continues to increase every combustion cycle, that is, when the combustion period IG90 is continuously shortened by a plurality of combustion cycles, it is determined that the possibility of knocking is high, The knock predictor flag is set to “1”.

The tendency for the temperature of the unburned region to increase continuously for each combustion cycle can be explained as follows.
That is, the combustion period IG90 becomes shorter as compared to the previous combustion cycle as the temperature rises due to heat transfer from the wall surface. Then, since the combustion period IG90 in the current combustion cycle is short, the heat transfer amount of the wall surface from the high-temperature combustion gas increases, and the wall surface temperature further increases.

As a result, in the next combustion cycle of the current combustion cycle, the amount of heat that the unburned region receives from the wall surface increases, so the temperature of the unburned region in the next combustion cycle becomes higher than the current combustion cycle. For this reason, the combustion period IG90 in the next combustion cycle is further shortened. By repeating such a phenomenon, the combustion period IG90 is shortened for each combustion cycle, and the temperature of the unburned region increases for each combustion cycle.

Based on this, in step S64, “1” is set to the knock predictor flag on condition that the combustion period IG90 is shortened over a plurality of combustion cycles. By setting the knock predictor flag in this way, it is possible to predict the occurrence of knock in the next combustion cycle without directly detecting the temperature of the unburned region, so control the ignition timing using the knock predictor flag. For example, knocking can be avoided in advance.

Alternatively, when the combustion period IG90 is shortened by a plurality of combustion cycles and the combustion period IG90 of the current combustion cycle exceeds a predetermined determination threshold value, the knock predictor flag may be set to “1”. is there. By setting the knock predictor flag in this way, it is possible to determine that knocking will occur when the wall surface temperature state in the next combustion cycle reaches a specific determination threshold value, so that the occurrence prediction of knocking can be improved. Can do.

Alternatively, the combustion period IG90 is shortened by a plurality of combustion cycles, and further, when the combustion period IG90 of the current combustion cycle exceeds a predetermined determination threshold value and knocking does not occur in step S63, a small amount of fuel The knock predictor flag may be set to “1” when a pressure vibration due to self-ignition of the light or a weak pressure vibration due to a low-temperature oxidation reaction is detected. By setting in this way, it is possible to predict the occurrence of low-temperature oxidation reaction or weak self-ignition, which is a sign of self-ignition leading to knock, and the occurrence of knock due to the temperature rise after that occurrence. Can be improved. When the setting of the knock predictor flag is completed, the process proceeds to step S65.

<< Step S65 >> In step S65, a knock generation flag is set based on the knock intensity detected in step S63. The knock generation flag is a flag that is set to “1” when a knock occurs and “0” when no knock occurs. When the knock intensity detected in step S63 exceeds a predetermined intensity that differs for each operating condition, the knock occurrence flag is set to “1”.

As described above, the knock predictor flag and the knock generation flag obtained in the control flow shown in FIG. 6 are sent to the knock controller 28 shown in FIG. 3 to control the ignition timing.

Next, calculation processing executed by the knock control unit 28 shown in FIG. 3 will be described with reference to FIG. The control flow shown in FIG. 8 shows a control flow for controlling the ignition timing with reference to the knock predictor flag and the knock occurrence flag obtained in the control flow shown in FIG.

<< Step S81 >> In step S81, it is determined whether or not knocking has occurred in the current combustion cycle. This determination can be made based on the knock occurrence flag set in step S65.
If the knock determination flag is “0”, the process proceeds to step S82, and if the knock determination flag is “1”, the process proceeds to step S85.

<< Step S82 >> In step S82, it is determined whether or not there is a sign of occurrence of knock in the current combustion cycle. This determination can be made based on the knock predictor flag set in step S64. If the knock predictor flag is “1”, it is predicted that a knock will occur, and the process proceeds to step S83. If the knock predictor flag is “0”, it is predicted that no knock will occur, and the process proceeds to step S84.

<< Step S83 >> In step S83, since the occurrence of knocking is predicted in the next combustion cycle, the target value for retarding the ignition timing is set. Here, the target value of the ignition timing is set by setting the target value of the ignition timing for the purpose of suppressing the rise in the wall temperature, which is a cause of occurrence of knocking, by subtracting the retardation target value from the reference ignition timing determined by the operating conditions. Exit. The retard target value is set to a value smaller than the knock retard target value of the retard control that is performed when the knock is generated. This setting method will be described with reference to FIG.

<< Step S84 >> Since it is determined that there is no sign of occurrence of knocking in Step S82, in Step S84, the current ignition timing map is set from the target ignition timing map set on the rotation / load map stored in the ROM 20d of the ECU 20. The ignition timing under the condition corresponding to the operating condition is calculated and the process goes to the end.

<< Step S85 >> Since it is determined in step S81 that knocking has occurred, in step S85, it is determined whether the frequency of knocking is high. The knock occurrence frequency can be determined from the relationship between the arithmetic mean value and the mode value of the combustion period IG90 in a plurality (predetermined number) of combustion cycles before the occurrence of knock under the current operating conditions. Here, if the difference between the arithmetic average value and the mode value is within a predetermined range, it is determined that the knock occurrence frequency is low, the mode value is larger, and the difference from the arithmetic average value is “predetermined value”. If it is larger, it is determined that the knock occurrence frequency is high.

For example, in consideration of the magnitude of “variation”, it is good to set “predetermined value” to about 3 ° to 5 ° in crank angle. If it is determined that the knock occurrence frequency is low, the process proceeds to step S84 to set the reference ignition timing described above. On the other hand, if it is determined that the knock occurrence frequency is high, the process proceeds to step S86.

<< Step S86 >> When it is determined in step S85 that the knock occurrence frequency is high, ignition timing retard processing based on knock detection is executed. In this case, the ignition timing of the next combustion cycle is retarded by a predetermined knock retardation target value at which knock does not occur, and exits to the end. The knock retardation target value is set to a value larger than the retardation target value when knocking is predicted as described above. In the subsequent combustion cycle, the ignition timing is sequentially advanced by a predetermined amount for each combustion cycle and returned to the reference ignition timing.

Next, the arithmetic processing executed in step S83 shown in FIG. 8 will be described with reference to FIG.

<< Step S91 >> In step S91, a wall temperature target value setting process is executed. Here, based on the average wall surface temperature map for each operation condition stored in the ROM 20d of the ECU 20, the target wall surface temperature Ttar [K] under the current operation condition is calculated. The average target wall surface temperature map can be determined by a prior experiment or a simulation under a predetermined operating condition.

If the target temperature of the average wall surface temperature is defined by the limit to the occurrence of knock, the target temperature tends to increase qualitatively in the increasing direction of the rotation speed, and the target temperature tends to decrease in the increasing direction of the load. Set to This is because the in-cylinder pressure is high under heavy load conditions, and the in-cylinder temperature in the unburned region due to the combustion phenomenon and piston compression increases, so it is necessary to lower the wall temperature, and the rotation speed is large. This is because the remaining time in the unburned region is shortened under the condition, and thus the in-cylinder temperature in the unburned region is allowed to be higher than when the rotational speed is low. When the target wall temperature Ttar is set, the process proceeds to step S92 to estimate the current wall temperature.

<< Step S92 >> In step S92, the current wall temperature is estimated. The wall temperature is estimated based on the coolant temperature Tw [K], the lubricating oil temperature To [K], the combustion period IG90 [deg] of the current combustion cycle, the knock intensity Pk [MPa] of the current combustion cycle, and the ignition timing ADV [ degATDC] or the like. That is, the wall temperature Twall [K] can be estimated as the following function using these estimation parameters as variables.
Twall = f1 (Tw, To, IG90, Pk, ADV)
Here, (1) the wall surface temperature increases as the water temperature and oil temperature increase, (2) the wall surface temperature increases as the combustion period becomes shorter, and (3) the wall surface temperature increases as the ignition timing advances. (4) Using the relationship that the wall surface temperature decreases as the knock intensity of the current combustion cycle increases, the above function can be expressed as follows.
Twall = (K _w × Tw) + (K _o × To) −K _IG90 × (IG90−IG90ref) + K _ADV × (ADV−ADVref) −K _Pk (Pk−Pkref)
Here, K _w , K _o , K _IG90 , K _ADV , and K _Pk are positive values, and are coefficients that vary depending on operating conditions and the internal combustion engine. “IG90ref” is a reference combustion period [deg], “ADVref” is a reference ignition timing [degATDC], and “Pkref” is a reference knock intensity [MPa], and these are arranged as a map for each operating condition. Stored in the ROM 20d. Thereby, the current wall surface temperature Twall can be estimated.

Thus, by estimating the wall surface temperature Twall for each variable, it is possible to estimate the wall temperature appropriately according to the operating conditions. Next, the process proceeds to step S93, and the ignition timing is controlled so that the estimated wall surface temperature Twall approaches the target wall surface temperature Ttar.

<< Step S93 >> In step S93, the ignition timing retardation target value set in step S83 of FIG. 8 is set so that the wall surface temperature Twall estimated in step S92 approaches the target wall surface temperature Ttar obtained in step S91. Perform the desired operation.

The ignition timing retardation target value ADVret [deg] can be obtained as a function of the wall surface temperature Twall and the target wall surface temperature Ttar shown below.
ADVret = f2 (Twall, Ttar) and the above function is expressed as follows because the ignition delay amount needs to be increased as the wall surface temperature Twall is higher and the difference from the target wall surface temperature Ttar is larger. Can do.
ADVret = F1 (Twall-Ttar)
Here, F1 is a positive coefficient, and the retard target value ADVret is set to be larger as the difference between the wall surface temperature Twall of the current combustion cycle and the target wall surface temperature Ttar is larger. For this reason, since the wall surface temperature Twall can be greatly reduced, the wall surface temperature Twall can be efficiently converged to the target wall surface temperature Ttar quickly.

When the combustion chamber wall temperature Twall is increased, the ignition timing is advanced, and when the combustion chamber wall temperature Twall is decreased, the ignition timing is retarded so that the actual combustion chamber wall temperature Twall is set to the target wall temperature. It is possible to converge to the temperature Ttar.

FIG. 10 shows a control result of the ignition timing according to the progress of the combustion cycle when the control of the ignition timing is executed using the first embodiment. In FIG. 10, (a) knock intensity, (b) combustion period, (c) average value (solid line) of burning period, mode value of combustion period (dashed line), (d) change in ignition timing for each combustion cycle Is shown. As for the ignition timing, the movement of the present embodiment is indicated by a solid line, and the movement of normal knock retard control is indicated by a broken line.

First, the combustion period tends to be shortened in the plurality of combustion cycles C1 and C2 before the combustion cycle C3, and the combustion period is further shortened in the current combustion cycle C3. It is determined that there is a high possibility that knocking will occur due to an increase in the temperature of the unburned area accompanying the rise in the wall temperature. Further, since the knock intensity is slightly increased, it can be determined that a low-temperature oxidation reaction has occurred, or that the combustion period is shorter than a predetermined value in the combustion cycle C3.

Based on this result, in the combustion cycle C4 following the combustion cycle C3, the ignition timing can be retarded to prevent knocking in the combustion cycle C4. In the case of conventional knock retardation control not using this embodiment, knock occurs in the combustion cycle C4 next to the combustion cycle C3, and this is detected and detected after two combustion cycles of the combustion cycle C3 (one combustion from the occurrence of knock). After the cycle), the ignition timing is retarded. Thus, in this embodiment, the occurrence of knock is predicted by estimating the wall temperature of the combustion chamber, and based on this, the ignition timing is retarded to converge to the normal wall temperature.

Further, in the combustion cycle C9, a state in which knocking occurs while no sign of occurrence of prior knocking is observed is shown. In normal knock retard control, ignition timing retard control is executed from the combustion cycle subsequent to the combustion cycle C9.

On the other hand, in the present embodiment, knock does not occur in the combustion cycles C4 to C8. Therefore, it is possible to continuously generate knock after the knock cycle based on the knock occurrence frequency in step S85 of FIG. It is determined whether or not the ignition performance is high. If it is determined that the ignition timing is low, the ignition timing retarding control is not executed.

As described above, in the present embodiment, the ignition timing of the combustion cycle in which the possibility of knocking is high is retarded, or the ignition delay control is not executed when knocking occurs under a condition where the frequency of knocking is low. As a result, unnecessary retard control of the ignition timing can be avoided, and fuel consumption deterioration can be suppressed. In addition, in the combustion cycle in which the occurrence of knocking is predicted, the ignition timing is retarded to control the wall surface temperature so that knocking occurs in the combustion cycle next to the combustion cycle in which knocking is predicted. Can be suppressed.

In this embodiment, the combustion period (crank angle) is used as an index representing the change in cooling loss, but this can also be used as the combustion phase. By using the combustion phase, the relationship between the piston position and the combustion is clarified, so that the estimation and correlation of the wall temperature become stronger and the estimation accuracy of the occurrence of knocking and the estimation accuracy of the wall temperature can be expected.

Next, a second embodiment of the present invention will be described with reference to FIG. 3, FIG. 8, FIG. 9, and FIG. FIG. 11 is a control flow for the arithmetic processing performed by the knock occurrence prediction unit 27 shown in FIG. 3, and is substantially the same as the processing content of the control flow shown in FIG. However, the second embodiment is different in that the in-cylinder pressure is used instead of the specific combustion ratio and the combustion period.

<< Step S111 >> In step S111, the maximum position (crank angle) of the in-cylinder pressure is detected. FIG. 12 explains the maximum position of the in-cylinder pressure. As shown in FIG. 12, the maximum position of the in-cylinder pressure indicates the crank angle at which the maximum value of the in-cylinder pressure in the current combustion cycle is located. Is.

If the operating conditions and the ignition timing are the same, the maximum position of the in-cylinder pressure is correlated with the combustion period, and if the combustion period is short, the maximum position of the in-cylinder pressure moves to the advance side. Thus, since the maximum position of the in-cylinder pressure is an amount having a correlation with the combustion period, the change in the cooling loss can be extracted from the change in the maximum position of the in-cylinder pressure. When the maximum position of the in-cylinder pressure is detected in step S111, the process proceeds to step S112, and the statistic of the maximum position of the in-cylinder pressure is calculated.

<< Step S112 >> In step S112, the statistic of the maximum position of the in-cylinder pressure is calculated. What is calculated in the calculation of the statistic is the statistical distribution and the average value, the mode value, and the history of a plurality of combustion cycles at the maximum position of the target in-cylinder pressure. Even at the maximum position of the in-cylinder pressure, in the operating condition where knock does not occur or the knock occurrence frequency is low, the occurrence frequency of the maximum position of each in-cylinder pressure is close to a normal distribution and is an average value as in FIG. 7A. And the mode value almost coincide. On the other hand, in the driving condition where the frequency of knocking is high, the mode value is shifted to the advance side as compared with the average value as in FIG. 7B. When the calculation of the statistics is completed, the process proceeds to step S113.

<< Step S113 >> In step S113, knock strength is calculated. Since step S113 is the same as step S63, the description thereof is omitted. When the knock strength is obtained, the process proceeds to step S114.

<< Step S114 >> In step S114, a knock predictor flag is set. The knock predictor flag is a flag that is set to “1” when the probability of knock occurrence is high in the next combustion cycle, and “0” when low.

[If the cooling loss continuously increases up to the current combustion cycle, the maximum position of the in-cylinder pressure continues to advance in multiple combustion cycles. Accordingly, the knock predictor flag can be set to “1” on condition that the maximum position of the in-cylinder pressure is advanced over a plurality of combustion cycles. This step S114 is substantially the same idea as step S64.

In addition, when the maximum position of the in-cylinder pressure is advanced in a plurality of combustion cycles and the maximum position of the in-cylinder pressure in the current combustion cycle is advanced from a predetermined determination threshold, the knock predictor flag is set. “1} may be set. By setting the knock predictor flag in this way, knocking occurs when the wall surface temperature state in the next combustion cycle reaches a specific determination threshold value. Since the determination can be made, the knock generation prediction accuracy can be improved.

Further, when the maximum position of the in-cylinder pressure is advanced in a plurality of combustion cycles, and the maximum position of the in-cylinder pressure of the current combustion cycle is advanced from a predetermined determination threshold value, and in step S113. Although knocking does not occur, the knocking predictor flag may be set to “1” when pressure vibration due to slight fuel self-ignition or weak pressure vibration caused by low-temperature oxidation reaction is detected. Is. " By setting in this way, it is possible to predict the occurrence of low-temperature oxidation reaction or weak self-ignition, which is a sign of self-ignition leading to knock, and the occurrence of knock due to the temperature rise after that occurrence. Can be improved. When the setting of the knock predictor flag is completed, the process proceeds to step S115.

<< Step S115 >> In step S115, a knock generation flag is set based on the knock intensity detected in step S113. Since step S113 is the same process as step S63, description thereof is omitted.

When the setting of the knock predictor flag and the knock occurrence flag is completed, the knock control unit 28 executes a control flow for controlling the ignition timing with reference to the knock predictor flag and the knock occurrence flag shown in FIG.

However, the processing of the control step executed in step S83 is different from that of the first embodiment. The processing executed in step S83 is shown in FIG. 9, and the point that the wall temperature estimation in step S92 is calculated using the maximum value position of the in-cylinder pressure in this embodiment is different.

The wall temperature is estimated based on the coolant temperature Tw [K], the lubricating oil temperature To [K], the in-cylinder pressure maximum position θpmax of the current combustion cycle, the knock intensity Pk [MPa] of the current combustion cycle, and the ignition timing ADV [ degATDC] or the like. That is, the wall temperature Twall [K] can be estimated as the following function using these estimation parameters as variables.
Twall = g1 (Tw, To, θpmax, Pk, ADV)
Here, (1) the wall surface temperature increases as the water temperature or oil temperature increases, (2) the wall surface temperature increases as the maximum position of the in-cylinder pressure advances, and (3) the wall surface temperature depends on the ignition timing (degATDC). ) Increases with advance, and (4) the wall temperature decreases as the knock strength of the current combustion cycle increases, the above function can be expressed as follows:
Twall = (K _w × Tw) + (K _o × To) −K _θp × (θpmax−θpmaxref) + K _ADV × (ADV−ADVref) −K _Pk (Pk−Pkref)
Here, K _w , K _o , K _θp , K _ADV , and K _Pk are positive values, and are coefficients that vary depending on operating conditions and the internal combustion engine. “Θpmaxref” is the maximum position of the reference in-cylinder pressure, and these are arranged as a map for each operating condition and stored in the ROM 20d. Thereby, the current wall surface temperature Twall can be estimated.

In step S93, an operation for obtaining a target value for retarding the ignition timing is executed so that the wall surface temperature Twall estimated in step S92 approaches the target wall surface temperature Ttar obtained in step S91.

The ignition timing retardation target value ADVret [deg] can be obtained as a function of the wall surface temperature Twall and the target wall surface temperature Ttar shown below.
ADVret = f2 (Twall, Ttar) and the above function is expressed as follows because the ignition delay amount needs to be increased as the wall surface temperature Twall is higher and the difference from the target wall surface temperature Ttar is larger. Can do. ADVret = F1 (Twall-Ttar)
Here, F1 is a positive coefficient, and the retard target value ADVret is set to increase as the difference between the wall temperature Twall of the current combustion cycle and the target wall temperature Ttar increases. Therefore, the wall temperature Twall can be greatly reduced. it can. For this reason, the wall surface temperature Twall can be quickly converged to the target wall surface temperature Ttar efficiently. Note that by changing the coefficient F1, it is possible to change the speed of approaching the target wall surface temperature in accordance with the wall surface temperature in the current combustion cycle.

As described above, the present invention includes a knock generation prediction unit that predicts the occurrence of knock based on a change in cooling loss (wall temperature change) of the internal combustion engine calculated based on a signal from an in-cylinder pressure sensor attached to the combustion chamber. The knock control unit is configured to control the ignition timing of the internal combustion engine based on knock prediction information related to the cooling loss detected by the knock generation prediction unit.

According to this, it is possible to predict the occurrence of knock due to the rise in wall temperature accompanying the increase in cooling loss and the accompanying rise in temperature in the unburned region, and to retard the ignition timing with the combustion cycle in which the occurrence of knock is predicted. Thus, knock can be effectively suppressed.

In addition, this invention is not limited to the above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Air flow sensor, 2 ... Electronic control throttle, 3 ... Fuel injection apparatus, 4 ... Ignition system, 5 ... Variable valve, 5a ... Intake valve variable device, 5b ... Exhaust valve variable device, 6 ... Intake pipe, 7 ... Cylinder head , 8 ... Exhaust pipe, 9 ... Air-fuel ratio sensor, 10 ... Three-way catalyst, 11 ... Exhaust temperature sensor, 12 ... Combustion chamber, 13 ... Crank angle sensor, 14 ... Coolant temperature sensor, 15 ... Intake temperature sensor, 16 ... Accelerator opening sensor, 17 ... high pressure fuel pump, 18 ... fuel pressure sensor, 20 ... internal combustion engine control unit, 20a ... input circuit, 20b ... input / output port, 20c ... RAM, 20d ... ROM, 20e ... CPU, 20f ... electronic Control throttle drive circuit, 20g ... injector drive circuit, 20h ... ignition output circuit, 20j ... variable valve drive circuit, 20k ... high pressure fuel port 20m ... knock detection unit, 20n ... knock avoidance control unit, 21 ... intake pressure sensor, 25 ... knock sensor, 26 ... in-cylinder pressure sensor, 27 ... knock generation prediction unit, 28 ... knock control unit, 100 ... internal combustion organ.

Claims

Based on detection information from an in-cylinder pressure sensor that detects the combustion pressure in the combustion chamber of the internal combustion engine, an ignition timing control means that determines the occurrence of knocking and controls the ignition timing, and an ignition control signal from the ignition timing control means In an ignition control device for an internal combustion engine comprising ignition output means for sending a drive output signal to an ignition plug provided in the combustion chamber,
The ignition timing control means includes
A knock occurrence prediction unit for predicting knock occurrence based on a factor correlated with a change in cooling loss calculated based on the detection information of the in-cylinder pressure sensor to obtain knock precursor information;
An ignition control device for an internal combustion engine, comprising: a knock control unit that corrects an ignition timing based on knock prediction information obtained by the knock occurrence prediction unit.
The ignition control device for an internal combustion engine according to claim 1,
Ignition control for an internal combustion engine characterized in that the knock generation prediction unit predicts knock based on a change in wall temperature of the combustion chamber as a factor having a correlation with a change in cooling loss and obtains the knock predictive information apparatus.
The ignition control device for an internal combustion engine according to claim 1,
The knock occurrence predicting unit obtains the knock predictive information by predicting a knock based on a change in the timing of reaching a specific combustion state as a factor correlated with a change in cooling loss. Ignition control device.
The ignition control device for an internal combustion engine according to claim 3,
The ignition control device for an internal combustion engine, characterized in that the time when the specific combustion state obtained by the knock generation prediction unit is reached is obtained based on the arrival time of the specific combustion ratio point detected by the in-cylinder pressure sensor.
The ignition control device for an internal combustion engine according to claim 3,
The internal combustion engine ignition control device characterized in that the time when the specific combustion state determined by the knock generation prediction unit is reached is determined based on the time when the in-cylinder pressure detected by the in-cylinder pressure sensor reaches a maximum value. .
The ignition control device for an internal combustion engine according to claim 1,
The knock generation prediction unit is configured to obtain knock prediction information by predicting knock based on a change in a combustion period until reaching a specific combustion state as a factor having a correlation with a change in cooling loss. An ignition control device for an internal combustion engine.
The ignition control device for an internal combustion engine according to claim 6,
The ignition control device for an internal combustion engine, wherein the combustion period obtained by the knock generation prediction unit is a period of arrival time from an ignition start timing by the spark plug to a specific combustion ratio point.
The ignition control device for an internal combustion engine according to claim 6,
The combustion period obtained by the knock generation prediction unit is a period from a first arrival time at which the first specific combustion ratio point is reached to a second arrival time at which the second specific combustion ratio point is reached. An internal combustion engine ignition control device.
In the ignition control device for an internal combustion engine according to claim 4 or 5,
The knock occurrence prediction unit
When the time to reach a specific combustion state changes continuously to the advance side over a plurality of combustion cycles, the knock predictor information is generated,
The internal combustion engine ignition control device, wherein the knock control unit generates a control signal obtained by retarding an ignition timing in a next combustion cycle based on the knock predictor information.
In the ignition control device for an internal combustion engine according to claim 4 or 5,
The knock occurrence prediction unit
The specific combustion state is changed from a predetermined time determined by the ignition start timing of the current combustion cycle when the time to reach the specific combustion state changes continuously to the advance side over a plurality of combustion cycles. When the combustion period until the arrival time is below the set value, the knock precursor information is generated,
The internal combustion engine ignition control device, wherein the knock control unit generates a control signal obtained by retarding an ignition timing in a next combustion cycle based on the knock predictor information.
In the ignition control device for an internal combustion engine according to claim 4 or 5,
The knock occurrence prediction unit
When the time to reach a specific combustion state changes continuously to the advance side over multiple combustion cycles, and the time to reach a specific combustion state in the current combustion cycle falls below the set value In addition, when the pressure vibration due to a slight fuel self-ignition or the weak pressure vibration due to the low temperature oxidation reaction is detected, the knock precursor information is generated,
The internal combustion engine ignition control device, wherein the knock control unit generates a control signal obtained by retarding an ignition timing in a next combustion cycle based on the knock predictor information.
9. The ignition control device for an internal combustion engine according to claim 7, wherein the knock occurrence predicting unit includes the knock predictor information when the combustion period continuously shifts in a shortening direction over a plurality of combustion cycles. Occur and
The internal combustion engine ignition control device, wherein the knock control unit generates a control signal obtained by retarding an ignition timing in a next combustion cycle based on the knock predictor information.
9. The ignition control device for an internal combustion engine according to claim 7, wherein the knock generation prediction unit is configured such that the combustion period continuously shifts in a shortening direction over a plurality of combustion cycles, and the current combustion cycle. When the combustion period falls below a set value, the knock precursor information is generated,
The internal combustion engine ignition control device, wherein the knock control unit generates a control signal obtained by retarding an ignition timing in a next combustion cycle based on the knock predictor information.
9. The ignition control device for an internal combustion engine according to claim 7, wherein the knock generation prediction unit is configured such that the combustion period continuously shifts in a shortening direction over a plurality of combustion cycles, and the current combustion cycle. In the case where the combustion period is less than or equal to the set value, the knock precursor information is generated when a pressure vibration caused by a slight amount of fuel self-ignition or a weak pressure vibration caused by a low temperature oxidation reaction is detected.
The internal combustion engine ignition control device, wherein the knock control unit generates a control signal obtained by retarding an ignition timing in a next combustion cycle based on the knock predictor information.
The ignition control device for an internal combustion engine according to claim 1,
The knock generation prediction unit includes a knock detection unit that detects the occurrence of knock by the in-cylinder pressure sensor, and a specific combustion from a predetermined timing determined by the arrival timing of the specific combustion break point detected by the in-cylinder pressure sensor or the ignition start timing. A combustion state calculation unit that calculates the combustion period until the time to reach the state,
The knock control unit
When knock generation is detected by the knock detection unit, the mode and average value of the combustion period detected by the combustion state calculation unit in the predetermined number of combustion cycles before the knock generation or the arrival time of the specific combustion ratio point If the difference is smaller than the predetermined value, the ignition timing in the next combustion cycle is maintained at the reference ignition timing,
An ignition control device for an internal combustion engine, wherein when the difference between the mode value and the average value is larger than a predetermined value, the ignition timing is retarded in the next combustion cycle in which knocking occurs.
The internal combustion engine ignition control device according to claim 9 or 12,
The knock control unit
Target wall surface temperature estimating means for determining a target wall surface temperature of the combustion chamber determined by the operating state of the internal combustion engine;
Wall surface temperature estimating means for estimating an actual wall surface temperature of the combustion chamber;
An ignition control device for an internal combustion engine, comprising: wall surface temperature control means for controlling the actual wall surface temperature to the target wall surface temperature.
The ignition control device for an internal combustion engine according to claim 16,
The internal combustion engine ignition control device characterized in that the wall surface temperature estimating means estimates the wall surface temperature based on at least one of information on cooling water temperature, oil temperature, ignition timing, and presence / absence of knock.
The ignition control device for an internal combustion engine according to claim 16,
The ignition control device for an internal combustion engine, wherein the wall surface temperature control means adjusts the wall surface temperature by controlling an ignition timing.
The ignition control device for an internal combustion engine according to claim 16,
The wall surface temperature control means advances the ignition timing when increasing the wall surface temperature of the combustion chamber, and retards the ignition timing when decreasing the wall surface temperature of the combustion chamber. Ignition control device.