JP2016205220A - Idle stop control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new idle stop control device capable of efficiently and rapidly restricting an increasing of engine speed at the time of automatic starting from an idle stop state.SOLUTION: A maximum value of engine speed for every combustion is attained after it is determined that a rotating state of an internal combustion engine is stabled at the time of automatic starting of the internal combustion engine, and further either a delayed amount of angle at the ignition time for decreasing a combustion torque corresponding to a deviation of the maximum value of the engine speed before and after every combustion or a reducing amount of the fuel injection amount is attained, and a combustion torque at each of the cylinders is controlled in reference to the delayed angle amount at the attained ignition time, or the ignition time reflected a reduction amount of the fuel injection amount, or injection amount of fuel. In accordance with this arrangement, it becomes possible to restrict efficiently and rapidly an increasing of the engine speed at the time of automatic starting from the idle stop state.SELECTED DRAWING: Figure 2A

Description

  The present invention relates to an idling stop control device for an internal combustion engine that automatically stops fuel injection and ignition of the internal combustion engine when the vehicle is stopped and automatically restarts fuel injection and ignition of the internal combustion engine by a start operation of the vehicle. is there.

  In recent years, for the purpose of improving fuel consumption and reducing exhaust emissions, an increasing number of automobiles are equipped with so-called idle stop control devices that automatically stop an internal combustion engine when the automobile is stopped at an intersection or the like. This idle stop control device stops the fuel injection and ignition when the driver stops the vehicle to automatically stop the internal combustion engine, and then the driver starts the vehicle to start the vehicle (brake When a release operation, accelerator depression operation, etc.) is performed, the starter motor is automatically energized to crank the internal combustion engine and restart it.

  By the way, when the internal combustion engine is started, the intake air amount and the fuel amount are increased so that the rotational speed is slightly increased. This blow-up injects more fuel than the amount of fuel injected during idling when the internal combustion engine is started in order to obtain sufficient air-fuel mixture to reliably burn the fuel when the internal combustion engine is started and to stabilize the combustion. It is caused by that.

  In an automobile equipped with an idle stop control device, for example, when idling waiting for a signal at an intersection, the internal combustion engine is automatically stopped when the brake pedal is depressed, and then the internal combustion engine is released when the depression of the brake pedal is released. Although the engine is configured to automatically start, in an automobile equipped with an automatic transmission mechanism, the gear of the automatic transmission mechanism is often in the travel range (D range).

  Therefore, when the gear of the automatic transmission mechanism is in the traveling range and the air amount or the fuel amount is set so that the rotational speed is increased as described above during the automatic start from the idle stop state, the start shock of the automobile Phenomenon such as jumping out. For this reason, there is a problem that makes the driver feel uncomfortable, and it is not preferable from the viewpoint of safety. Therefore, for example, as disclosed in Japanese Patent Application Laid-Open No. 2012-87651 (Patent Document 1), the generation of combustion torque is suppressed by a method such as air supply amount reduction processing at start-up and ignition timing retardation processing, and rotation is performed. It has been proposed to take measures against the rising number.

  By the way, since the control for suppressing the increase in the rotational speed of the internal combustion engine is the control for suppressing the combustion torque, it is necessary to avoid the adverse effect of the shortage of the combustion torque at the initial stage of starting. For this reason, it is desirable that the control for suppressing the increase in the rotational speed be performed after the completion of the explosion determination.

  However, in general, the target rotational speed at idling is set lower as the cooling water temperature of the internal combustion engine rises, and the rotational speed has already increased to around the target rotational speed at the time of complete explosion determination at restart after idling stop. Often doing. For this reason, even if the reduction process of the air supply amount or the retarding process of the ignition timing is performed after the completion of the explosion determination, the increase in the rotational speed cannot be suppressed well.

  Therefore, in order to obtain a predetermined blow-up suppressing effect, it is necessary to set a large control amount for air and ignition timing. However, the increase in the rotational speed varies depending on the environmental conditions, fuel properties, machine differences of the internal combustion engine, etc., so if the control amount is set large, the combustion speed deteriorates and the rotational speed decreases. This causes a problem that the rotational speed becomes too high.

  Therefore, in Patent Document 1, the maximum value of the rotation speed is measured a predetermined number of times, the average value of the maximum rotation speed is calculated, and the fluctuation amount is calculated by comparison with a preset reference rotation speed. Further, when the fluctuation amount deviates from a predetermined range, the ignition timing advance / retard amount and intake air supply amount are corrected.

  According to this method, when the maximum value of the average rotational speed deviates from a predetermined range at the time of automatic start, at least one of the ignition timing or intake air amount at the next automatic start is corrected based on the fluctuation amount. The As a result, the maximum value of the rotation speed at the next start approaches the reference rotation speed maximum value, so the maximum value of the rotation speed becomes lower than the target rotation speed and the engine cannot start, or conversely the maximum rotation speed It can be prevented that the value becomes higher than the target rotational speed and the shock increases.

JP 2012-87651 A

  However, since the method according to Patent Document 1 retards the ignition timing from the vicinity of the reference maximum rotational speed or reduces the amount of air, there is a problem that it is not possible to quickly and efficiently suppress the rotational speed.

  An object of the present invention is to provide a novel idle stop control device capable of quickly and efficiently suppressing the rotation speed increase at the time of automatic start from the idle stop state.

  The feature of the present invention is that, when the internal combustion engine is automatically started, the maximum rotational speed value is determined for each combustion after it is determined that the rotational state of the internal combustion engine is stable, and further, the deviation of the maximum rotational speed value for each subsequent combustion is dealt with. A retard amount of the ignition timing or a decrease amount of the fuel injection amount for reducing the combustion torque is calculated, and an ignition timing or fuel injection reflecting the calculated retard amount of the ignition timing or the decrease amount of the fuel injection amount is obtained. The combustion torque of each cylinder is controlled by the amount.

  According to the present invention, since the combustion torque of each cylinder is controlled by a correction amount obtained from the deviation of the maximum number of rotations for each combustion, the rotation speed increase at the time of automatic start from the idle stop state is quickly and efficiently suppressed. Will be able to.

It is a block diagram of the control system of the internal combustion engine carrying the idle stop control apparatus with which this invention is applied. It is explanatory drawing which shows the first half of the control flow for demonstrating the ignition timing at the time of the restart from the idle stop state which becomes embodiment of this invention, or control of the fuel injection amount. It is explanatory drawing which shows the second half of the control flow for demonstrating the continuation of the control flow of FIG. 2A. It is explanatory drawing explaining determining combustion stability by the angular velocity in an expansion stroke. It is explanatory drawing explaining determining combustion stability by the angular velocity in the combustion order from starting. It is explanatory drawing explaining determining combustion stability by the rotation speed maximum value for every combustion. It is explanatory drawing explaining determining combustion stability by the rotation speed maximum value in the combustion order from starting. It is explanatory drawing explaining the relationship between the change state of the deviation of a rotation speed maximum value, and the correction amount corresponding to this. It is explanatory drawing explaining the relationship between the deviation of rotation speed maximum value, and a correction amount. It is explanatory drawing explaining the timing which reflects the correction | amendment corresponding to the deviation of rotation speed maximum value. It is explanatory drawing explaining the reflection method of the correction amount at the time of completion | finish of blowing-up of rotation speed. It is explanatory drawing explaining the method of calculating | requiring the correction amount at the time of completion | finish of blowing-up of rotation speed. It is explanatory drawing explaining the relationship between the deviation | deviation of the rotation speed at the time of a peak, and a peak determination rotation speed, and a correction amount.

  Next, 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 included in the range.

  FIG. 1 shows the configuration of a control system for an internal combustion engine equipped with an idle stop control device. The present embodiment is a control system used for an in-cylinder in-line four-cylinder internal combustion engine, and the internal combustion engine control device 10 and the idle stop control device 11 are configured as separate control devices. Without being separated in this way, the internal combustion engine control device 10 and the idle stop control device 11 may be mounted on a common control board to form a single control device.

  As shown in FIG. 1, an air cleaner 14 is provided at the most upstream portion of the intake pipe 13 of the internal combustion engine 12. A throttle valve 16 whose opening degree is adjusted by a DC motor 15 is provided on the downstream side of the air cleaner 14. The DC motor 15 is driven based on a signal (accelerator opening signal) from an accelerator opening sensor that detects a driver's accelerator depression amount (accelerator opening). Specifically, the opening degree (throttle opening degree) of the throttle valve 16 is controlled based on a signal output from the internal combustion engine control device 10 according to the accelerator opening degree.

  The amount of air taken into each cylinder is adjusted according to the throttle opening. A throttle sensor that detects the throttle opening is provided in the vicinity of the throttle valve 16. An air flow meter 17 for detecting the intake air amount is provided between the air cleaner 14 and the throttle valve 16.

  A surge tank 18 is provided on the downstream side of the throttle valve 16, and an intake pressure sensor that detects the pressure in the intake pipe is provided in the surge tank 18. The surge tank 18 is connected to an intake manifold that introduces air into each cylinder of the internal combustion engine 12. An intake port is formed in the intake manifold of each cylinder, and this intake port is connected to an intake valve formed in each cylinder of the internal combustion engine 12.

  Each cylinder of the internal combustion engine 12 is provided with a fuel injection valve 19 that injects fuel directly into the combustion chamber of each cylinder. The fuel is supplied to the fuel injection valve 19 by two pumps, a fuel pump (not shown) and a high pressure pump (not shown). In order to inject fuel directly into the combustion chamber, the injection fuel pressure needs to be higher than the pressure in the combustion chamber.

  For this reason, first, fuel is sucked up by a fuel pump (not shown) disposed in the fuel tank 20 to increase the pressure of the fuel. Further, the pressure is increased by a high pressure pump provided in the fuel pipe, and the pressure is fed to a delivery pipe (not shown). The fuel pressurized by the high-pressure pump becomes a predetermined pressure within a range of 2 to 10 MPa, for example, and is distributed to the fuel injection valves 19 of the respective cylinders by the delivery pipe. This high-pressure fuel is injected from the fuel injection valve 19 into the combustion chamber, and mixed with the intake air supplied from the intake port to form an air-fuel mixture.

  The air-fuel mixture in the combustion chamber is ignited by a spark plug 21 attached to the cylinder head of the internal combustion engine 12. The spark plug 21 is attached to each cylinder, and the air-fuel mixture in the cylinder is ignited by the spark discharge of each spark plug 21.

  The air-fuel mixture explodes and expands by ignition, and the piston 22 moves downward in the drawing, whereby the crankshaft rotates through the connecting rod. A crank angle sensor 23 is provided outside the diameter of the crankshaft. The crank angle sensor 23 detects the rotation angle (crank angle) and rotation speed of the crankshaft and inputs the detected rotation angle to the internal combustion engine control apparatus 10. The internal combustion engine control apparatus 10 calculates the rotational speed, the rotational increase rate, and others of the internal combustion engine 12 based on the crank angle and the rotational speed. Further, a water temperature sensor is provided in the cylinder block of the internal combustion engine 12, and the cooling water temperature of the internal combustion engine 12 is detected and output to the internal combustion engine control device 10.

  Exhaust gas discharged from the exhaust valve of the internal combustion engine 12 merges into one exhaust pipe 24 via the exhaust manifold. The exhaust pipe 24 is connected to a three-way catalyst 25 that purifies exhaust gas near the stoichiometric air-fuel ratio. In addition, air-fuel ratio sensors 26 and 27 for detecting the air-fuel ratio of the exhaust gas are provided upstream and downstream of the three-way catalyst 25.

  Output signals from the various sensors described above are input to the internal combustion engine control apparatus 10. The internal combustion engine control device 10 is mainly composed of a microcomputer, and includes a CPU (Central Processing Unit), a ROM (storage medium), a RAM (temporary storage medium), and the like. The internal combustion engine control device 10 stores a control program and a control map. For example, a target air-fuel ratio map for calculating the target air-fuel ratio in accordance with the operation status of the internal combustion engine (internal combustion engine speed and intake air amount) is stored. The DC motor 15, the fuel injection valve 19, and the spark plug 21 are controlled based on various sensor outputs by such a control program and control map.

  On the other hand, signals from the brake switch 28, the accelerator depression amount sensor 29, the vehicle speed sensor 30, the transmission oil temperature sensor 31, and the like are input to the idle stop control device 11, and the idle stop condition and the automatic start condition are determined based on these input conditions. Judgment.

  Further, it communicates with the internal combustion engine control device 10, and when the idle stop condition is satisfied, the fuel injection from the fuel injection valve 19 and the ignition of the ignition plug 21 are stopped, and the internal combustion engine 12 is automatically stopped. When the automatic start condition is satisfied, the automatic start is performed. Specifically, when the driver depresses the brake pedal while idling (the vehicle speed is zero), the automatic stop condition is satisfied and the internal combustion engine 12 is stopped, and the driver applies the brake during the automatic stop. When the accelerator is depressed during release or automatic stop, the automatic start condition is satisfied and the internal combustion engine 12 is automatically started. At this time, the idle stop control device 11 is configured to automatically start by rotating the starter motor 32 by energizing the relay 33 for the starter motor 32.

  Incidentally, at the time of starting the internal combustion engine by operating the ignition switch and at the time of automatic starting after the idling stop, the engine speed is controlled so as to return to the idle engine speed after being blown up once. The increase in the rotational speed is caused by injecting more fuel than the amount of fuel injected at idling at the time of starting in order to obtain a sufficient mixture to stabilize the combustion at the time of starting. ing.

  In the following embodiment, an object of the present invention is to efficiently and promptly suppress the increase in the rotational speed at the time of automatic start from the idle stop state. For this reason, in the following description, control at the time of automatic start from the idle stop state will be described.

  2A to 2B are control flows for explaining a control operation when automatic start is performed from the idle stop state. This control flow is not used in an actual control program, but is a control flow for explaining a control method.

  First, when the brake pedal is released or the accelerator pedal is depressed and automatic start is started from the idle stop state, the angular velocity between the predetermined crank angles of the first combustion cylinder is measured in step S10. In this case, the angular velocity between the predetermined crank angles is preferably measured during a predetermined angular range during the expansion stroke. When the measurement of the angular velocity is completed, the process proceeds to step S11, and the measured angular velocity is compared with a predetermined angular velocity threshold A. Thus, it is determined whether a predetermined angular velocity is obtained from the combustion torque generated by the combustion. When the determination condition in step S11 is satisfied, the process proceeds to step S12. When the determination condition is not satisfied, the process returns to step S10, and the angular velocity between the predetermined crank angles of the next combustion cylinder is measured. In this embodiment, the combustion order of each cylinder is in the order of 1 cylinder → 3 cylinder → 4 cylinder → 2 cylinder. Steps S10 and S11 function as stable state determination means for determining that the rotational state of the internal combustion engine is stable when the angular velocity of the expansion stroke of each cylinder exceeds a predetermined angular velocity threshold.

  Next, a method for determining the combustion state at the time of restart by measuring the angular velocity between the predetermined crank angles of the expansion stroke executed in steps S10 and S11 described above will be described based on FIGS. 3A and 3B.

  The rotational speed of the internal combustion engine shown in FIG. 3A shows the behavior of the rotational speed change when the engine is restarted from the idle stop state. The rotational speed of the internal combustion engine is, for example, a rotation calculated from a periodic change every crank angle of 10 degrees. Is a number. FIG. 3A shows a case where the first combustion cylinder is the first cylinder, and the combustion is performed in the order of the third cylinder, the fourth cylinder, the second cylinder, etc., and the rotation speed corresponds to this combustion order. As a result, the rotational speeds N1, N3, N4, N2,.

  Further, the angular velocity ω of the internal combustion engine is an angular velocity calculated by a predetermined crank angle θ / elapsed time Δt in the expansion stroke of each cylinder, and this also changes as angular velocities ω1, ω3, ω4, ω2,. It is. For example, the rotational speed Nn indicated by a solid line shows an example in which the combustion state at the time of restart is good and sufficient combustion torque is obtained. Therefore, if the angular velocity during the expansion stroke is large, the rotational speed is relatively short. Is up.

  On the other hand, the rotational speed Nm shown by the broken line shows an example in which the combustion state at the time of restart is not good, and the combustion torque is not sufficiently obtained, so the angular velocity in the expansion stroke does not increase so much, and the rotational speed Nn Compared to this, the rise in the rotational speed is slightly slower.

  FIG. 3B shows the relationship between the angular velocity and the combustion order in these two examples. An example in which combustion is good is indicated by a solid line, and an example in which combustion is not good is indicated by a broken line. The rotational speed increases in accordance with the combustion order of each cylinder. As can be seen from FIG. 3B, in the example of good combustion, the angular velocity is already the angular velocity in the third cylinder after the first combustion cylinder (first cylinder). Since the threshold value A is exceeded, it can be determined that combustion is being performed satisfactorily.

  On the other hand, in the example where the combustion is not good, the angular velocity exceeds the angular velocity threshold A in the second cylinder after the fourth cylinder, so that it can be seen that the combustion is not performed well. In this way, by comparing the angular velocity of each combustion cylinder with the predetermined angular velocity threshold A, it can be determined whether or not the combustion state is good.

  Returning to FIG. 2A, the angular velocity measured in step S11 is compared with a predetermined angular velocity threshold A, and if it is determined that the angular velocity exceeds the angular velocity threshold A, the process proceeds to step S12. In step S12, the maximum value of the rotational speed between predetermined crank angles is measured. In this case, the maximum value of the rotational speed between predetermined crank angles is preferably measured for each combustion of each cylinder.

  When the measurement of the maximum rotational speed is completed, the process proceeds to step S13, and the measured maximum rotational speed is compared with a predetermined rotational speed threshold B. The rotation speed threshold B is set to 300 rpm to 400 rpm. Thus, it is determined whether the rotational speed has increased to a predetermined rotational speed. When the determination condition in step S13 is satisfied, the process proceeds to step S14. However, when the determination condition is not satisfied, the process returns to step S12 again, and the maximum rotation speed value of the next cylinder is measured. Steps S12 and S13 function as stable state determination means for determining that the rotational state of the internal combustion engine is stable when the maximum rotational speed value for each combustion of each cylinder exceeds a predetermined rotational speed threshold value.

  Next, a method for determining the combustion state at the time of restart by measuring the maximum value of the rotational speed executed in steps S12 and S13 described above will be described based on FIGS. 4A and 4B.

  The rotational speed of the internal combustion engine shown in FIG. 4A shows the behavior of the rotational speed change when restarting from the idle stop state, and the rotational speed of the internal combustion engine is, for example, a rotation calculated from a periodic change every crank angle of 10 degrees. Is a number. FIG. 4A shows a case where the first combustion cylinder is the first cylinder, and the combustion is performed in the order of the third cylinder, the fourth cylinder, the second cylinder, etc., and the rotation speed corresponds to this. Rotational speeds N1, N3, N4, N2,.

  The maximum value of the rotational speed is the maximum value of the rotational speed for each combustion of each cylinder. In order to capture the rotational speed change due to combustion, the maximum values N1max, N3max, N4max between predetermined crank angles including the expansion stroke. , N2max... In this order. Here, if the maximum value of the rotation speed is measured or estimated, it may be a partial angle range of the expansion stroke. Similar to that shown in FIG. 3A, the rotational speed Nn indicated by the solid line shows an example in which the combustion state at the time of restart is good and sufficient combustion torque is obtained, so the rotational speed can be achieved in a relatively short time. Standing up.

  On the other hand, the rotational speed Nm indicated by the broken line shows an example in which the combustion state at the time of restart is not good, and since the combustion torque is not sufficiently obtained, the rise of the rotational speed is slightly slower than the rotational speed Nn. Yes.

  FIG. 4B shows the relationship between the rotation speed maximum value and the combustion order in these two examples. An example in which combustion is good is indicated by a solid line, and an example in which combustion is not good is indicated by a broken line. The rotational speed increases in accordance with the combustion order of each cylinder. As can be seen from FIG. 4B, in the example where combustion is good, the rotational speed is already maximum in the third cylinder after the first combustion cylinder (first cylinder). Since the value exceeds the rotation speed threshold value B, it can be determined that combustion is being performed satisfactorily.

  On the other hand, in an example in which combustion is not good, it can be seen that combustion is not being performed well because the maximum rotation speed value exceeds the rotation speed threshold B in the second cylinder after the fourth cylinder. In this way, it is possible to determine whether or not the combustion state is good by comparing the maximum rotational speed value for each combustion cylinder with the predetermined rotational speed threshold value B.

  As described above, in steps S10 and S11, it is determined whether or not a good combustion state has been obtained by detecting the combustion state at the time of restart of each cylinder from the angular velocity between the predetermined crank angles of the expansion stroke. In S12 and S13, it is determined whether or not the rotational speed has increased to a predetermined rotational speed by detecting the maximum rotational speed value for each combustion of each cylinder. In some cases, the combustion state may be determined using only one of them. However, in this embodiment, since the combustion torque is controlled using the maximum rotation speed value, at least the maximum rotation speed value is measured.

  Returning to FIG. 2A, if it is determined in step S13 that the maximum rotational speed value exceeds the predetermined rotational speed threshold B, the process proceeds to step S14. In step S14 and subsequent steps, a process for reducing the combustion torque is executed to control the increase in the rotational speed. In step S14, it is determined whether or not the rotation of the internal combustion engine is sufficiently stable.

  In step S14, it is determined whether the angular velocity exceeds the angular velocity threshold A and the maximum rotational speed value exceeds the rotational speed threshold B. If this determination condition is not satisfied, the process returns to step S10 again and the control steps described above are repeated.

  On the other hand, when the determination condition is satisfied in step S14, it is determined that good combustion is obtained, and control for suppressing the blow-up is executed. In order to suppress the blow-up, it is only necessary to reduce the combustion torque. Therefore, the process proceeds to the step of performing the retarding process of the ignition timing or the reducing process of the fuel injection amount in order to reduce the combustion torque.

  If it is determined in step S14 that the condition is satisfied, the process proceeds to step S15, and a deviation between the maximum rotational speed value generated by the previous combustion at this time and the maximum rotational speed value generated by the current combustion is calculated. . If the deviation is large, the rotational speed increases rapidly, so it is considered that the degree of blow-up will increase. If the deviation is small, the increase in rotational speed is approaching the end time, so it is assumed that the degree of blow-up is small. Is done. Therefore, as will be described later, it is possible to determine the correction amount for reducing the combustion torque by predicting the subsequent increase in the rotational speed. This step S15 functions as a rotation speed maximum value measuring means for measuring the rotation speed maximum value for each combustion of each cylinder.

  When the deviation between the maximum rotational speed value generated in the previous combustion and the maximum rotational speed value generated in the current combustion is obtained in step S15, the process proceeds to step S16. In step S16, based on the magnitude of the deviation calculated in step S15, the ignition timing retard amount for suppressing the combustion torque or the correction amount calculation of the fuel injection amount decrease amount is executed. The retard amount and the fuel decrease amount are determined by a function of the deviation, and may be obtained by a function expression, or the table is stored with the deviation, the retard amount and the fuel decrease amount stored in a table. You may ask for it. This step S16 functions as a correction amount calculation means for calculating a retard amount of the ignition timing or a decrease amount of the fuel injection amount for reducing the combustion torque in accordance with the deviation.

  FIG. 5 shows the calculation method of the retard amount of the fire timing or the decrease amount of the fuel injection amount described above. The correction amount, such as the retard amount of the ignition timing or the decrease amount of the fuel injection amount, is measured by measuring the maximum number of revolutions between the predetermined crank angles including the expansion stroke of each cylinder, and the maximum number of revolutions generated by the previous combustion and this time Is obtained based on the deviation of the maximum value of the rotational speed caused by the combustion of.

  Specifically, the deviations A to D of the maximum value of the rotational speed for each combustion become smaller as the rotational speed increases, as shown in the lower side of FIG. As the correction amounts a to d for the retard amount and the fuel decrease amount calculated in this way, a larger correction amount is set as the deviation of the maximum rotational speed value is larger, and a smaller correction amount is set as the deviation is smaller. “Uppercase letters A to D” representing the deviation correspond to “lowercase letters a to d” representing the correction amount. Therefore, a small correction value is gradually calculated as the rotational speed increases.

  The reason for this is that, as described above, if the deviation is large, the rotational speed increases rapidly, so it is considered that the degree of blow-up increases, and if the deviation is small, the rotational speed rise approaches the end time. This is because it is considered that the degree of blow-up is small. Therefore, the greater the deviation, the greater the combustion torque suppression effect.

  The retard amount of the ignition timing and the decrease amount of the fuel injection amount are corrected for the final ignition timing and the final fuel injection amount calculated for each combustion. Further, regarding the amount of decrease in the fuel injection amount, when the fuel injection amount is greater than the fuel injection amount calculated for each combustion, a fuel cut can be performed.

  FIG. 6 shows the relationship between the deviation of the maximum rotational speed value and the correction amount. The correction amount is divided into three areas with respect to the deviation of the maximum rotational speed value. In “Region O” where the deviation of the maximum value of the rotational speed is small, the state where the rotational speed has almost reached a peak state and the rotational speed has settled down, or the rotational speed has stopped rising due to deterioration of combustion during the start-up. Since there is a state of occurrence, the retard amount of the ignition timing or the decrease of the fuel injection amount is unnecessary, so the correction amount is set to almost “0”.

  Further, in the “region Q” where the deviation of the maximum value of the rotational speed is large, the correction amount is set to be a large correction amount that can rapidly suppress the rotational speed after starting. However, if the correction amount is increased unnecessarily corresponding to the deviation, the occurrence of engine stall or the like is expected, so the correction amount is set to a certain limited value. That is, the maximum limit value of the correction amount is used. Further, between “region P” between “region O” and “region Q”, the correction amount is set to gradually change in accordance with the magnitude of the deviation. The correction amount corresponding to this deviation may be obtained by a functional equation as described above, or may be obtained by a table lookup method.

  Returning to FIG. 2A, when the correction calculation of the retard amount of the ignition timing and the decrease amount of the fuel injection amount is completed in step S16, the process proceeds to step S17, where the ignition timing is finally corrected and calculated or the fuel injection amount is finalized. Correction calculation. Then, fuel is actually injected to form an air-fuel mixture, and this air-fuel mixture is ignited by a spark plug, and then an explosion and an expansion process are started. Note that the ignition timing and fuel injection amount before the correction calculation may be those calculated by an ignition control program or fuel control program that is started at another start timing, or the control steps in the previous stage of this program It may be calculated by. This step S17 controls the combustion torque of each cylinder of the internal combustion engine by calculating the ignition timing retarded amount calculated by the correction amount calculating means or the ignition timing reflecting the decrease amount of the fuel injection amount or the fuel injection amount. Functions as fuel injection means and ignition control means.

  The injection process and the ignition process based on the correction calculation executed in step S17 are performed according to the correction amount calculated in step S16 after the predetermined number of cylinders have been burned after the condition in step S14 is satisfied. Thus, the logic may be set so as to implement the retard of the ignition timing or the reduction of the fuel injection amount (including the fuel cut).

  FIG. 7 shows the timing at which the ignition timing is retarded or the fuel injection amount is reduced, and is based on the time when the determination in step S14 of FIG. 2A is established. When step S14 is established, the ignition process and the fuel injection process are performed reflecting the correction amount after a predetermined delay period DLY has elapsed.

  Also in this case, as shown in FIG. 5, the deviation between the maximum rotational speed value generated in the previous combustion reflecting the correction amount and the maximum rotational speed value generated in the current combustion is calculated. Similarly, in the following, the deviation between the maximum rotational speed value generated in the previous combustion and the maximum rotational speed value generated in the current combustion is obtained, and the corresponding correction amount, that is, the decrease amount of the fuel injection amount or the ignition timing delay is obtained. The angular amount is calculated.

  Here, the delay period may be a crank angle such as an elapsed time, a predetermined number of combustion times, or the number of ignition times. Further, for example, the correction amount can be reflected when the combustion order of the combustion cylinder comes again with reference to the combustion cylinder when step S14 is established. In any case, by performing the fuel injection amount reduction process and the ignition timing retarding process for each cylinder before the engine speed increases, the combustion torque is suppressed and the engine speed increases rapidly. Can be efficiently suppressed.

  It should be noted that both the fuel injection amount reduction amount and the ignition timing retardation amount may be reflected, but either one may be reflected. For example, when the rotational speed deviation is large, the fuel injection amount reducing process and the ignition timing retarding process or the ignition timing retarding process are executed, and when the rotational speed deviation is small, the fuel injection amount reducing process is performed. The process may be executed. This is because the effect of suppressing the combustion torque by the process of reducing the fuel injection amount is smaller than that at the ignition timing, and it is advantageous to reflect it when the deviation of the rotational speed is small.

  Returning to FIG. 2A, when the fuel injection amount decreasing process or the ignition timing retarding process is executed in step S17, the deviation of the maximum rotational speed calculated in step S15 is within a predetermined value ΔN in step S18. Judging whether it has become. In step S18, it is determined whether or not the end of the speed increase after the start has been reached, or whether or not the rotation speed has increased and stopped during the start. This step S18 functions as a deviation amount determining means for determining whether or not the deviation calculated by the rotation speed maximum value deviation calculating means is smaller than a predetermined value.

  Therefore, when the condition that the deviation of the maximum rotational speed value is greater than or equal to the predetermined value is not satisfied in step S18, the process returns to step S15 and the control of steps S15 to S17 is repeated again to reduce the fuel injection amount. Ignition timing retarding processing is executed.

  On the other hand, when the condition is satisfied, it is determined that the speed increase after the start has reached the end time, or that the speed increase has been stagnant during the start. In these cases, it is not necessary to perform the fuel injection amount reduction process or the ignition timing retard process, and therefore the process proceeds to step S19 to maintain (hold) the values of the ignition timing retard quantity and the fuel injection quantity decrease. And the subsequent ignition timing retarding process and the fuel injection amount reducing process are not executed. This step S19 stops the calculation of the correction amount when it is determined that the deviation is smaller than the predetermined value, and holds the combustion torque of each cylinder of the internal combustion engine according to the ignition timing or the fuel injection amount previously calculated for correction. Functions as a means.

  FIG. 8 illustrates the processing of steps 18 and 19. As described above, the rotational speed Nn increases with each combustion, and the maximum rotational speed for each combustion is measured. Deviations A to G between the maximum rotational speed value measured in the previous combustion cylinder and the maximum rotational speed value measured in the current combustion cylinder are sequentially calculated according to the progress of combustion. This deviation becomes smaller as the rotational speed increases, and the deviation becomes equal to or less than a predetermined value ΔN when the rotational speed reaches the end of the blow-up. For example, in FIG. 8, ΔN> deviation G. In this case, the current state is maintained because the fuel injection amount reduction control and the ignition timing retardation control are not required.

  In addition to this, even when a combustion failure occurs during the start-up and the increase in the rotational speed Nm is temporarily stagnated, the deviation is equal to or less than the predetermined value ΔN. Therefore, by detecting such behavior in steps S18 and S19, it is possible to prevent deterioration of combustion due to overcorrection by maintaining the ignition timing retard amount or the fuel injection amount decrease amount without changing it. It becomes.

  The process after step S19 is the process after the state where the rotational speed has finished being blown up, and at step S20, the peak rotational speed of the rotational speed is measured. As shown in FIG. 8, when the deviation of the maximum rotational speed value for each combustion hardly changes, or the sign of the deviation changes, or the average rotational speed of a plurality of maximum rotational speed values, as shown in FIG. When the change direction of the maximum value is changed, it can be determined that the peak value of the blow-up has been reached. It should be noted that other methods for measuring the peak rotational speed of the blow-up can be adopted. Step S functions as a peak rotational speed measuring means for measuring the peak rotational speed of the rotational speed.

  When the blow-up peak rotational speed is measured in step S20, the process proceeds to step S21. In step S21, a target blow-up peak determination rotational speed (hereinafter referred to as a peak determination threshold) and the measured blow-up peak rotational speed are determined. Calculate the deviation. Step S21 functions as a peak time deviation calculating means for calculating the peak time deviation by comparing the blow-up peak rotational speed with a predetermined blow-up peak determination rotational speed.

  The reason for obtaining this deviation is as follows. When restart is performed with the blow-up suppressed by the processing from step S15 to step S19 described above, the blow-up suppression degree may be different. For example, when the influence of the correction amount that suppresses the blow-up is large, the blow-up peak rotational speed is lower than the target rotational speed. Conversely, when the influence of the correction amount that suppresses the blow-up is small, the blow-up peak rotational speed is It becomes higher than the target speed. Therefore, a countermeasure for this is required.

  When a deviation from the peak determination threshold value is obtained in step S21, a correction amount that eliminates this deviation is calculated in step S22. This correction amount is an increase / decrease amount of the fuel injection amount, an advance / retard amount of the ignition timing. In steps S15 to S19, the fuel injection amount is decreased and the ignition timing is retarded to suppress the blow-up, but in step S22, it is necessary to increase the fuel injection amount and advance the ignition timing. It is. Step S22 functions as a peak correction amount calculating means for calculating the peak correction amount of the ignition timing advance, retard amount, or fuel injection amount increase / decrease amount corresponding to the peak time deviation.

  FIG. 9 illustrates the processing of steps 21 and 22. As described above, the rising peak rotational speed of the rotational speed varies depending on the degree of influence of the correction amount. For example, in the case of (1) the rotational speed NA where the rotational peak rotational speed is lower than the peak determination threshold, (2) the peak In the case of the rotational speed NB having a high peak rotational speed with respect to the determination threshold, (3) there may be a rotational speed NC in which the upward peak rotational speed substantially matches the peak determination threshold. In the case of the rotational speed NA, the deviation from the peak determination threshold is “ΔA”, in the case of the rotational speed NB, the deviation from the peak determination threshold is “ΔB”, and in the case of the rotational speed NC, the deviation from the peak determination threshold value. The deviation is “about 0”. These deviations are calculated in step S21.

  Then, a correction amount corresponding to this deviation is calculated in step S22. In the case of the rotational speed NA, it is necessary to increase the combustion torque because the peak rotational speed is lower than the peak determination threshold. For this reason, the peak correction amount “Δ” a for increasing the combustion torque is obtained from the current correction amount. On the other hand, in the case of the rotational speed NB, it is necessary to reduce the combustion torque because the peak rotational speed is higher than the peak determination threshold. For this reason, the peak correction amount “Δb” for reducing the combustion torque from the current correction amount is obtained.

  In order to increase the combustion torque, it is only necessary to increase the fuel injection amount or advance the ignition timing. Further, as described above, in order to reduce the combustion torque, it is sufficient to reduce the fuel injection amount and retard the ignition timing. In the case of the rotational speed NC, since the peak determination threshold value and the rising peak rotational speed are substantially the same, it is not necessary to increase or decrease the combustion torque, and the peak correction amount is “0”.

  FIG. 10 shows the relationship between the deviation and the correction amount. In FIG. 10, the horizontal axis represents the deviation from the peak determination threshold, and the vertical axis represents the peak correction amount. In the range X in a predetermined range in which the deviation of the blow-up peak rotational speed is positive and negative from “0”, the correction amount “0” is set because the peak correction amount is not necessary.

  In the region Y in the negative deviation direction where the blow-up peak rotational speed is smaller than the peak determination threshold, a negative peak correction amount is calculated. This negative peak correction amount is a correction amount for increasing the combustion torque, and corresponds to the correction amount “Δa” in FIG. On the contrary, in the region Z in the positive deviation direction where the blow-up peak rotational speed is larger than the peak determination threshold value, the positive peak correction amount is calculated. This positive peak correction amount is a correction amount for reducing the combustion torque, and corresponds to the correction amount “Δb” in FIG.

  The correction amounts for the positive peak correction amount and the negative peak correction amount are determined based on the same idea as the regions P and Q in FIG. That is, in the “region Y2” and “region Z2” with large deviations, a large correction amount that can control the rotational speed greatly is set. In addition, the “region Y1” and “region Z1” between “region X” and “region Y2” and between “region X” and “region Z2” are gradually corrected in accordance with the magnitude of the deviation. It is set to change. The correction amount corresponding to this deviation may be obtained by a functional equation or may be obtained by a table lookup method.

  When the peak correction amount is calculated in step S22, the process proceeds to step S3. In this step S23, the ignition timing is finally corrected and calculated based on the peak correction amount obtained in step S22, or the fuel injection amount is finally determined. Perform correction calculation. Then, fuel is actually injected to form an air-fuel mixture, and this air-fuel mixture is ignited by a spark plug, and then an explosion and an expansion process are started.

  When the step 23 is executed, if the blow-up peak rotational speed is larger than the peak determination threshold by a predetermined value or more, the ignition timing and the fuel injection amount are corrected so that the rotational speed decreases, and the blow-up peak rotational speed is more than the peak determination threshold. When the value is smaller than the predetermined value, the ignition timing and the fuel injection amount are set to be corrected so as to increase the rotational speed. In this manner, the blow-up rotation speed is controlled so as to approach the predetermined peak determination threshold value.

  When the process in step S23 ends, the process proceeds to step S4, and in this step S24, the peak correction amount calculated in step S22 is stored. Here, the deviation between the peak determination threshold value and the rising peak rotation speed appears as a machine difference variation of the internal combustion engine. In order to compensate for this machine difference variation, the peak correction amount is reflected at the next restart. The stored peak correction amount is used for the ignition timing in step S17 or the fuel injection amount correction calculation at the next restart from the idle stop state, and is used to retard the ignition timing and reduce the fuel injection amount. Reflect in quantity.

  That is, the final correction amount is obtained by adding or subtracting the stored peak correction amount to the correction amount calculated in step S15, and the final correction amount is used as the ignition timing or fuel injection amount in step S17. It is used when the correction calculation is performed, and is reflected in the retard of the ignition timing and the decrease in the fuel injection amount.

  As described above, according to the present invention, when the internal combustion engine is automatically started, the maximum rotational speed for each combustion is determined after it is determined that the rotational state of the internal combustion engine is stable, and the maximum rotational speed for each subsequent combustion is determined. The ignition timing retardation amount or the fuel injection amount decrease amount for reducing the combustion torque corresponding to the deviation of the ignition timing is calculated, and the ignition timing reflecting the calculated ignition timing retardation amount or the fuel injection amount decrease amount is calculated. Alternatively, the combustion torque of each cylinder is controlled by the fuel injection amount. According to this, it is possible to efficiently and quickly suppress the rotation speed increase at the time of automatic start from the idle stop state.

  In addition, this invention is not limited to an above-described 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 10 ... Internal combustion engine control apparatus, 11 ... Idle stop control apparatus, 12 ... Internal combustion engine, 13 ... Intake pipe, 14 ... Air cleaner, 15 ... DC motor, 16 ... Throttle valve, 17 ... Air flow meter, 18 ... Surge tank, 19 ... Fuel injection valve, 20 ... Fuel tank, 21 ... Spark plug, 22 ... Piston, 23 ... Crank angle sensor, 24 ... Exhaust pipe, 25 ... Three-way catalyst, 26 ... Air-fuel ratio sensor, 27 ... Air-fuel ratio sensor, 28 ... Brake Switch 29 Accelerator depression amount sensor 30 Vehicle speed sensor 31 Transmission oil temperature sensor 32 Starter motor 33 Relay

Claims (8)

The fuel injection process for injecting fuel from the fuel injection valve when the predetermined automatic stop condition is satisfied and the ignition process for burning the injected fuel are stopped, and the fuel injection process is performed when the predetermined automatic start condition is satisfied And an idling stop control device for an internal combustion engine comprising control means for automatically starting the internal combustion engine by restarting the ignition process,
The control means obtains the maximum number of revolutions for each combustion after it is determined that the rotational state of the internal combustion engine is stable during the automatic start of the internal combustion engine, and further determines the maximum number of revolutions for each successive combustion. An ignition timing retard amount that reduces the combustion torque corresponding to the deviation or a decrease amount of the fuel injection amount is obtained, and an ignition timing that reflects the obtained retard amount of the ignition timing or the decrease amount of the fuel injection amount, Alternatively, an idling stop control device for an internal combustion engine, wherein the combustion torque of each cylinder of the internal combustion engine is controlled by a fuel injection amount. In the internal combustion engine idle stop control device according to claim 1,
The control means is a first stable state judging means for judging that the rotational state of the internal combustion engine is stable when at least a maximum rotational speed value for each combustion of each cylinder exceeds a predetermined rotational speed threshold value, An idle stop control device for an internal combustion engine, comprising: a second stable state determination means for determining that the rotational state of the internal combustion engine is stable when an angular velocity of an expansion stroke of a cylinder exceeds a predetermined angular velocity threshold value. . In the internal combustion engine idle stop control device according to claim 1,
The control means includes a rotation speed maximum value measuring means for measuring a rotation speed maximum value for each combustion of the cylinders, and a rotation speed maximum value deviation calculating means for calculating a deviation of the rotation speed maximum value for each preceding and following combustion. Correction amount calculating means for calculating a retard amount of the ignition timing or a decrease amount of the fuel injection amount for reducing the combustion torque corresponding to the deviation, and the ignition obtained by the correction amount calculating means A fuel injection means and an ignition control means for controlling a combustion torque of each cylinder of the internal combustion engine by calculating an ignition timing reflecting a retard amount of the timing or a decrease amount of the fuel injection quantity or a fuel injection quantity; An idling stop control device for an internal combustion engine. In the internal combustion engine idle stop control device according to claim 3,
The correction amount calculating means calculates the larger retard amount or the decrease amount of the fuel injection amount as the deviation of the maximum rotational speed value is larger, and decreases the retard amount or the fuel injection amount as the deviation is smaller. An idling stop control device for an internal combustion engine characterized by calculating an amount. In the internal combustion engine idle stop control device according to claim 1,
The control means obtains the maximum value of the number of revolutions for each combustion of each of the cylinders after the predetermined delay period has elapsed after it is determined that the rotational state of the internal combustion engine has become stable, and further the combustion of each of the cylinders preceding and following The ignition timing retardation amount or the fuel injection amount decrease amount corresponding to the deviation of the maximum value of each revolution is obtained, and the obtained ignition timing retardation amount or fuel injection amount decrease amount is reflected. An idle stop control device for an internal combustion engine that controls combustion torque of each cylinder of the internal combustion engine according to an ignition timing or a fuel injection amount. In the internal combustion engine idle stop control device according to claim 3,
The control means determines whether the deviation calculated by the rotation speed maximum value deviation calculating means is smaller than a predetermined value, and determines that the deviation is smaller than the predetermined value by the deviation amount determining means. And a holding means for controlling the combustion torque of each cylinder of the internal combustion engine according to the ignition timing or the fuel injection amount that has been previously calculated for correction without calculating the correction amount by the correction amount calculation means. An idling stop control device for an internal combustion engine. In the internal combustion engine idle stop control device according to claim 1,
The control means includes a peak rotational speed measuring means for measuring the rotational speed peak rotational speed, and a peak time deviation for calculating the peak time deviation by comparing the rotational speed peak rotational speed with a predetermined rotational peak judgment rotational speed. Calculated by the calculation means, the peak correction amount calculation means for calculating the advance / retard amount of the ignition timing or the increase / decrease amount of the fuel injection amount corresponding to the peak time deviation, and the peak correction amount calculation means An internal combustion engine that controls the combustion torque by correcting the ignition timing calculated by the ignition means or the fuel injection means or the fuel injection quantity based on the amount of increase or decrease in the advance, retardation amount, or fuel injection quantity. Stop control device. The internal combustion engine idle stop control device according to claim 7,
The peak correction amount is stored in a storage unit provided in the control means, and the ignition timing retardation amount or the fuel injection amount decrease amount obtained by the correction amount calculation means at the next automatic start is calculated. An idle stop control device for an internal combustion engine, which is used for correction.

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