JP4899772B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine that performs valve overlap control that overlaps a part of an open period of an intake valve and a part of an open period of an exhaust valve.

  Exhaust gas recirculation (hereinafter referred to as EGR), in which a part of exhaust gas is recirculated into a cylinder and mixed with newly sucked air, is used in various vehicles. As a result, the oxygen concentration of the air in the combustion chamber can be lowered, the combustion in the cylinder can be made moderate to lower the combustion temperature, and the generation of NOx (nitrogen oxide) can be reduced. The EGR includes a so-called external EGR that supplies exhaust gas in the exhaust passage to the intake passage, and a so-called internal EGR that returns the exhaust gas in the exhaust passage directly into the combustion chamber. Among these, the internal EGR opens the intake valve disposed between the combustion chamber and the intake passage when the exhaust valve disposed between the combustion chamber and the exhaust passage of the internal combustion engine is open, This is caused by overlapping a part of the valve opening period and a part of the intake valve opening period.

  In this internal EGR, the exhaust gas recirculation amount that is taken into the combustion chamber, that is, the remaining exhaust gas recirculation, varies due to the differential pressure between the intake side and the exhaust side. Therefore, when the fluctuation of the differential pressure becomes large during transient operation, the internal EGR cannot leave an appropriate amount of exhaust gas in the combustion chamber. In order to solve this problem, for example, Patent Document 1 proposes an exhaust gas purification device for an internal combustion engine. When the differential pressure on the exhaust side and the intake side fluctuates, this device appropriately adjusts the opening of the exhaust throttle valve provided in the exhaust passage downstream of the exhaust valve, thereby Thus, the magnitude of the exhaust pressure is set to a desired value, and a desired amount of exhaust gas is recirculated into the combustion chamber.

JP 2003-97252 A

  However, in the device described in Patent Document 1, an exhaust throttle valve must be provided for adjusting the opening degree of the exhaust passage, and there is a problem that the structure becomes complicated when considering application to various vehicles.

  Therefore, the present invention does not complicate the structure, and even during transient operation, an appropriate amount of exhaust gas is burned by overlapping a part of the intake valve open period and a part of the exhaust valve open period. It is an object of the present invention to provide a control device for an internal combustion engine that can be left in a chamber.

  In order to achieve the above object, an internal combustion engine control apparatus according to the present invention controls an internal combustion engine that performs valve overlap control to overlap a part of an open period of an intake valve and a part of an open period of an exhaust valve. An apparatus for determining whether or not the valve overlap occurs, ignition means for igniting an air-fuel mixture in the combustion chamber at a predetermined ignition timing, and air intake into the combustion chamber A throttle valve for adjusting the amount, a required throttle opening deriving means for deriving a required throttle opening which is a target value of the opening of the throttle valve, and whether or not the required throttle opening has changed transiently It is determined that the valve overlap occurs by the requested throttle opening degree determination means and the valve overlap determination means, and the Correction means for correcting the first ignition timing after the determination based on the required throttle opening when it is determined by the required throttle opening determining means that the required throttle opening has changed transiently. It is characterized by that.

  According to such a configuration, when it is determined that the valve overlap is generated by the valve overlap determining means, and the required throttle opening is determined to be transiently changed by the required throttle opening determining means, the correcting means is Since the first ignition timing after the determination is corrected based on the required throttle opening, it becomes possible to adjust the exhaust pressure to an appropriate pressure with respect to the intake pressure due to the fluctuation of the throttle valve opening. . Therefore, even during transient operation, the remaining amount of exhaust gas in the combustion chamber can be set to an appropriate amount by overlapping a part of the open period of the intake valve and a part of the open period of the exhaust valve. It becomes possible. In this way, an appropriate amount of exhaust gas can remain in the combustion chamber, so that the present invention can be applied to various vehicles without complicating the structure.

  The correction means may correct the initial ignition timing to be retarded when the required throttle opening increases transiently. On the other hand, the correction means may correct the advance of the first ignition timing when the required throttle opening is transiently decreased.

  Preferably, the internal combustion engine is a multi-cylinder internal combustion engine, and the control device of the internal combustion engine controls the opening degree of the throttle valve to the required throttle opening degree derived by the required throttle opening degree derivation means. The throttle opening control means for determining that the valve overlap is generated by the valve overlap determination means, and the required throttle opening determination means by the required throttle opening determination means. Is determined to have changed transiently, the first intake stroke after the first ignition timing in one target cylinder subject to control in which the first ignition timing first appears after the determination time. At the start of the throttle, so that the intake pressure of the intake port of the target cylinder reaches the intake pressure corresponding to the required throttle opening. To start delayed the opening change of Rubarubu. As a result, a part of the exhaust stroke that can cause fluctuations in the exhaust pressure by correcting the ignition timing, and an intake stroke that is affected by the intake pressure change due to a change in the opening of the throttle valve. It becomes possible to overlap a part more reliably. However, it is preferable that the intake pressure of the intake port of the target cylinder is the pressure at the most downstream point of the intake port.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, a first embodiment of the present invention will be described. FIG. 1 is a conceptual diagram of a vehicle engine system to which the control device for an internal combustion engine of the first embodiment is applied. The engine (internal combustion engine) 10 of the first embodiment is a port injection type spark ignition internal combustion engine.

  In the engine 10, air (intake air) drawn from the intake port is introduced into the intake passage 14 via the air cleaner 12. The intake passage 14 is mainly formed by an intake pipe 16, a surge tank 18, an intake manifold 20, and an intake port 22. The air flows into the surge tank 18 while the flow rate thereof is adjusted by the opening degree of the throttle valve 24 provided in the middle of the intake pipe 16, and the intake manifold 20 formed in a branched manner corresponding to each cylinder (cylinder) 26. Divide into The opening degree of the throttle valve 24 is adjusted by the throttle actuator 30 so as to correspond to the depression amount of the accelerator pedal 28 operated by the driver. Thus, the throttle valve 24 is an intake throttle valve that can electronically control its opening and closing operation.

  A fuel injection valve 32 is disposed in the intake manifold 20. The fuel injected by the fuel injection valve 32 is mixed with the diverted air, and an ignition plug 38 that is operated by the control of the ignition coil 36 via the intake valve 34 is provided in the combustion chamber 40 provided in the upper center. Inhaled.

  In the combustion chamber 40 of each cylinder 26, the air-fuel mixture is ignited by a spark plug 38. A flame generated by the ignition gradually propagates to the entire air-fuel mixture, and the air-fuel mixture burns. Exhaust gas generated by the combustion is discharged to the exhaust passage 44 via the exhaust valve 42. Exhaust gas is purified and discharged into the atmosphere by passing through a catalytic converter 52 disposed in the middle of an exhaust pipe 50 that defines the exhaust passage 44 together with the exhaust port 46 and the exhaust manifold 48.

  In the first embodiment, the valve operating mechanism (not shown) that opens and closes the intake valve 34 and the exhaust valve 42 can freely set the phase and lift amount of the operating angle (operating angle) of the intake valve 34 and the exhaust valve 42. The variable valve mechanism is variable, that is, the valve timing is freely variable, and the lift amount is freely variable. More specifically, in the first embodiment, this valve operating mechanism moves the intake valve 34 and the exhaust valve 42 by the electromagnetic force of the electromagnetic coil, and these intake / exhaust valves 34 and 42 are electromagnetically driven valves. Yes. Therefore, the phase of the working angle and the lift amount can be freely changed by the electromagnetic force generated by the energization drive controlled by the electromagnetic coils of the intake valve 34 and the exhaust valve 42.

In order to perform fuel injection control, ignition timing control, and the like, an electronic control unit (ECU: Electronic Control Unit) 54 is provided. The ECU 54 is constituted by a microcomputer including a CPU, a ROM and a RAM for recording various programs and data, an input interface circuit, and an output interface circuit. The input interface circuit includes a knock sensor 58 for detecting high-frequency vibration caused by knocking transmitted to the cylinder block 56, an intake pressure sensor 60 for detecting intake pressure downstream of the throttle valve 24, and the opening of the throttle valve 24. That is, the throttle position sensor 62 for detecting the throttle opening (actual throttle opening) TA, the accelerator position sensor 64 for detecting the depression amount of the accelerator pedal 28, that is, the accelerator opening, and the cylinder block 56 are provided. The crank position sensor 70 for detecting the crank rotation signal of the crankshaft 68 to which the piston 66 is connected via the connecting rod, and the cylinder block 56 are provided with the temperature of the cooling water (cooling water temperature) of the engine 10. For detecting Temperature sensor 72, such as O ₂ sensor 74 for detecting the oxygen concentration in the exhaust gas flowing through upstream of the catalytic converter 52 is connected via the electrical wiring. In the first embodiment, the crank position sensor 70 is used as a rotational speed sensor for detecting the rotational speed (rotational speed) of the engine 10. The output interface circuit of the ECU 54 is connected to the fuel injection valve 32, the ignition coil 36 with a built-in igniter, the valve operating mechanism, the throttle actuator 30, and the like, and is obtained based on output signals from the various sensors. Based on the obtained data, the ECU 54 controls them.

  In the engine 10, intake pressure based on the output signal from the intake pressure sensor 60, accelerator opening based on the output signal from the accelerator position sensor 64, engine speed based on the output signal from the crank position sensor 70, that is, engine load and A basic fuel injection amount, a basic fuel injection timing, a basic ignition timing, and the like are set by searching data stored in the ROM in advance based on the operating state represented by the engine speed. Then, these basic values are corrected by the coolant temperature of the engine 10, etc., and the fuel injection amount, fuel injection timing, ignition timing, etc. targeted for control are derived, and the operation of the fuel injection valve 32, spark plug 38, etc. Is controlled.

  Specifically, the ECU 54 of the engine 10 normally knocks the basic ignition timing obtained by comprehensively determining the state of the engine 10 based on the operating state and searching for data stored in advance in the ROM. An optimal ignition timing SA is determined by performing advance angle correction or delay angle correction by correction or the like. Then, by sending an ignition signal to the igniter, ignition of the air-fuel mixture at the determined ignition timing SA is executed.

  Further, in the engine 10, the operations of the intake valve 34 and the exhaust valve 42 are controlled by the valve timing and the lift amount derived by searching the data stored in the ROM in advance based on the operation state. The ECU 54 controls the valve mechanism. In the first embodiment, when starting the engine 10 or during light load operation, or during operation at a high load range and high rotation, the valve timing is set so as to eliminate valve overlap. The mechanism is controlled. On the other hand, the valve operating mechanism is controlled so that a valve timing at which a predetermined amount of valve overlap occurs during an intermediate load operation or an operation in a high load range and a low / medium load rotation. In this way, the ECU 54 performs valve overlap control.

Normally, ECU 54 includes a target value for control of the throttle opening degree, the required throttle opening TA _t, as the current throttle opening TA is matched is performed throttle opening control. The required throttle opening TA _t, the amount of depression of the accelerator pedal 28 by the driver, that is, a value corresponding to the accelerator opening.

  Then, in order to adjust the internal EGR amount to a desired amount, during transient operation, in other words, the accelerator opening greatly changes at a rapid speed, and the throttle opening greatly changes at a rapid speed. For example, the ECU 54 corrects the ignition timing SA. This control will be described based on the flowchart of FIG. However, the flowchart of FIG. 2 is repeated every predetermined time, for example, approximately every 20 ms. As described above, the ECU 54 performs the ignition timing correction control according to the flowchart of FIG. 2 separately from the normal control while the normal ignition timing control and the throttle opening degree control are being performed. .

  First, in step S201, the ECU 54 determines whether or not there is an operation state in which a part of the opening period of the intake valve 34 overlaps a part of the opening period of the exhaust valve 42 and valve overlap occurs. This is performed by searching for mapped data (not shown) based on the driving state. If the result is negative, the routine is terminated. On the other hand, if affirmed, the process proceeds to step S203. Note that the determination in step S201 corresponds to determining whether or not valve overlap occurs.

  In step S203, the current throttle opening (actual throttle opening) TA is detected. This is derived based on the output signal from the throttle position sensor 62.

Then, in step S205, required throttle opening TA _t is derived. This is a value corresponding to the accelerator opening obtained based on the output signal from the accelerator position sensor 64. Request More specifically, stored in advance in ROM, and wherein searching a map of data that defines the relationship between the accelerator position and the required throttle opening degree TA _t, corresponding to the current accelerator opening throttle opening TA _t is determined.

Then, in step S207, required throttle opening degree TA _t the magnitude of the difference between the current throttle opening TA _(| TA t -TA |) whether exceeds a predetermined amount ε or not. Note that the determination in step S207 corresponds to determination of whether or not the required throttle opening has changed transiently. Current and throttle opening TA determined in step S203, the absolute value of the difference between the required throttle opening TA _t obtained in step S205, i.e. required throttle opening TA relative to the current throttle opening TA the value of deviation of the _{t (|} TA _t -TA |) is compared with a predetermined amount of epsilon. However, the predetermined amount epsilon, desired for it is difficult size to obtain the internal EGR amount is the difference between the required throttle opening degree TA _t and the current throttle opening TA, stored in ROM sought by experiment Has been. When it is determined that the predetermined amount ε is not exceeded and the result is negative, the routine is terminated. On the other hand, if the determination in step S207 is affirmative, the process proceeds to step S209. Note that affirmative determination in step S207 means that an appropriate EGR amount cannot be ensured by valve overlap unless the ignition timing SA is corrected according to the present invention.

Proceeding to step S209, whether the required throttle opening TA _t determined in step S205, the difference between the current throttle opening TA detected in step S203 _(TA t -TA) is greater than "0" It is determined whether or not it is positive. This determination is required throttle opening TA _t is one in which the current throttle opening TA, to determine whether or not to request that changes the direction of the opening increases. Further in other words, this determination is to corresponds to determining whether when the required throttle opening TA _t is increased.

The determination of the step S207 and the step S209 are both in the difference between the required throttle opening degree TA _t and the current throttle opening TA corresponds to determining whether exceeds a predetermined amount. More specifically, the required throttle opening degree TA _t and makes a determination difference (TA t _-TA) is positive or negative and the current throttle opening TA, in addition, it is a predetermined amount when the positive "ε Corresponds to determining whether or not the predetermined amount “−ε” is exceeded on the negative side. That is, these determinations are either required throttle opening TA _t that is when transiently increased, it whether it is time decreased transiently, or whether it is unchanged transiently, are either This corresponds to the determination for determining whether or not.

Reaches the difference between the required throttle opening degree TA _t and the current throttle opening TA at step S209 is affirmative as exceeds "0", the flow proceeds to step S211, the ignition timing SA is derived based on the operating state The In the next step S213, the ignition timing SA obtained in step S211 is corrected by a predetermined retardation amount ΔSA. As a result, the first ignition timing SA immediately after the determination in step S207 and step S209 is retarded, and ignition is performed at the retarded ignition timing SA. Note that the predetermined retardation amount ΔSA is obtained in advance by experiments and stored in the ROM. Preferably, by this correction, the ignition timing SA is retarded until a predetermined timing of several degrees after the compression top dead center. However, the retardation correction of the ignition timing SA in step S213 is applied only to the first ignition timing after affirmation in step S209. Therefore, the next ignition timing SA is the ignition timing SA that is normally obtained as described above based on the operating state, in which the retardation correction in step S213 is not performed.

  On the other hand, when the result in step S209 is negative, the process proceeds to step S215, and the ignition timing SA is derived in the same manner as in step S211. In the next step S217, the ignition timing SA is corrected in a direction opposite to that in step S215, that is, on the advance side, by a predetermined retardation amount ΔSA. As a result, the first ignition timing SA immediately after the determination in step S207 and step S209 is advanced, and ignition is performed at the advanced ignition timing SA. However, the advance angle correction of the ignition timing SA in step S217 is applied only to the first ignition timing after being denied in step S209. Therefore, the next ignition timing SA is the ignition timing SA that is normally obtained as described above based on the operating state, in which the advance angle correction in step S217 is not performed.

  Next, effects and the like by such control will be described in detail. First, the case where the control of the first embodiment is not performed will be described based on the conceptual diagram of FIG. Next, the case where the control of the first embodiment is performed will be described based on the conceptual diagram of FIG.

A case where the control of the first embodiment is not performed will be described. In an operating state in which the ECU 54 controls the valve mechanism so that a part of the opening period of the intake valve 34 and a part of the opening period of the exhaust valve 42 overlap, at time tc1, the accelerator pedal 28 is suddenly changed. When the pedal is depressed, the opening degree of the throttle valve 24 is controlled so that the throttle opening degree TA increases rapidly (see FIG. 3A). Then, the intake pressure _PIM increases as the throttle opening suddenly increases (see FIG. 3B). An amount of air corresponding to the intake pressure _PIM is sucked into the combustion chamber 40 during the intake stroke, and an air-fuel mixture is formed using the sucked air. The exhaust gas generated by the combustion of the air-fuel mixture is discharged in the exhaust stroke, and the exhaust pressure _PEM starts to increase (see FIG. 3C). Therefore, a time Δt for one cycle is required from when the intake pressure P _IM starts to rise until the exhaust pressure P _EM starts to rise. That is, even begins to rise intake pressure P _IM, immediately without starting to rise exhaust pressure P _EM, after time Δt has elapsed for one cycle, so that the exhaust pressure P _EM starts to rise. Therefore, after the intake pressure P _IM starts to rise, in the first valve overlap, the fluctuation of the differential pressure between the intake pressure P _IM and the exhaust pressure P _{EM at} that time becomes large, as shown in FIG. for example the pressure difference is temporarily rapidly decreases the intake air pressure P _IM and exhaust pressure P _EM to (undershoot). As a result, the internal EGR amount r _e obtained by valve overlap at that time, (see FIG. 3 (e)) that will undershoot correspondingly. Therefore, it is not possible to continue to give the desired internal EGR amount r _e corresponding to the operation state, so that the exhaust emission is temporarily deteriorated.

In contrast, by performing the control of the first embodiment, it is possible such to obtain proper internal EGR quantity r _e of the desired amount even when. This case will be described. Note that the curve represented by the dotted line in FIG. 4 relates to the case where the present invention is not applied. In an operating state where the ECU 54 controls the valve mechanism so that part of the open periods of the intake and exhaust valves 34 and 42 overlap, if the accelerator pedal 28 is suddenly depressed at time tc2, the throttle opening TA The degree of opening of the throttle valve 24 is controlled so as to increase rapidly (see FIG. 4A). Then, the intake pressure _PIM increases as the throttle opening suddenly increases (see FIG. 4B). On the other hand, when the throttle opening TA is rapidly increased, the time tc2 first ignition timing immediately after the SA, i.e., the amount of air based on the throttle opening TA which roughly coincides with the required throttle opening TA _t of abrupt acceleration demand In the intake stroke before the air is sucked into the combustion chamber 40, the ignition timing SA of the air-fuel mixture containing the air sucked into the combustion chamber 40 is retarded. In other words, since this time is affirmative in steps S207 and S209, the ignition timing SA is retarded by a predetermined retardation amount ΔSA in step S213, which is adopted as the next first ignition timing SA. (See FIG. 4C). Accordingly, after-burning of the air-fuel mixture is promoted, for example, such that a portion combustion in the exhaust passage 44 occurs, the exhaust pressure P _EM starts to rise immediately after time tc2 (see FIG. 4 (d)). Therefore, as described above, when the intake pressure _PIM increases due to the change in the throttle opening TA, the exhaust pressure _PEM exhausted from the combustion chamber 40 also increases, and a high exhaust pressure _PEM is obtained. The exhaust stroke to be performed and the intake stroke in which intake is performed based on the high intake pressure _PIM are overlapped by one valve overlap. That is, the differential pressure between the exhaust pressure P _EM and the intake pressure P _IM of across the combustion chamber 40 as shown in FIG. 4 (e), without undershoot smoothly in response to changes in the accelerator opening Will change. As a result, it becomes possible to prevent the undershoot occurs in the internal EGR amount r _e (see FIG. 4 (f)). That is, it is possible by the valve overlap at that time to obtain a desired internal EGR quantity r _e.

In the above, with reference to FIGS. 3 and 4, for example rapid acceleration, such as required throttle opening TA _t is conceptually described as being transiently increased, for example, rapid deceleration, etc. required throttle opening TA _t is The same is true for a transient decrease. However, in this case, since the intake air pressure P _IM in response to the throttle opening TA becomes smaller based on the required throttle opening TA _t is decreased, the ignition thereto to lower the exhaust pressure P _EM compatible The timing SA is corrected in advance. As a result, it is possible to prevent the overshoot occurs in the internal EGR amount r _e, it is possible to obtain a desired internal EGR amount.

Next, a second embodiment of the present invention will be described. Tokoro In the second embodiment, as in the first embodiment, when there is a transient operation request, the ignition timing SA determined based on the operating state at that time, based on the required throttle opening degree TA _t not only performs correction control for retarding or advancing only quantitative [Delta] SA, also controls the timing of operation to correspond to the opening degree of the throttle valve 24 provided in the intake passage 14 to the required throttle opening degree TA _t . This will be described in detail below.

  However, since the vehicle engine system to which the second embodiment is applied is substantially the same as that of the first embodiment, the same components are denoted by the same reference numerals, and redundant description thereof is omitted here. . The engine 10 of the second embodiment is a port injection type spark ignition type internal combustion engine and an in-line four-cylinder internal combustion engine.

  The control in 2nd Embodiment is demonstrated based on the flowchart of FIG. 2 and FIG. However, the flowcharts of FIGS. 2 and 5 are repeated every predetermined time, for example, approximately every 20 ms.

ECU54 that the normal ignition timing control and the throttle opening control and the like performed as described above, when the difference between the required throttle opening degree TA _t and the throttle opening TA exceeds the positive or negative predetermined amount ± epsilon, the The initial ignition timing SA of each of all the cylinders immediately after is retarded or advanced. Since this description is the same as that described with reference to FIG. 2 in the first embodiment, a duplicate description is omitted here.

To work with correction control of such ignition timing SA, ECU 54 controls the timing changing to change it as the current throttle opening TA is equal to the required throttle opening TA _t. In step S501, the ECU 54 determines whether or not the operation state in which valve overlap occurs is the same as in step S201. If the result is NO here, the routine ends. On the other hand, if an affirmative the process proceeds to step S503, similarly current throttle opening TA and the step S203 is detected, similarly to the step S205 required throttle opening TA _t is derived in step S505 behind. Then, similarly to the S207, the magnitude of the difference between the required throttle opening degree TA _t and the current throttle opening TA at step S507 _(| TA t -TA |) it is determined whether more than a predetermined amount ε The If it is determined that the predetermined amount is not exceeded and the result is negative, the routine is terminated. On the other hand, if the determination in step S507 is affirmative, the process proceeds to step S509.

Incidentally, in controlling the timing changing the throttle opening degree, the determination difference of whether or not more than a predetermined amount ε of the required throttle opening degree TA _t and the current throttle opening TA, the required throttle opening degree TA _t When the difference from the current throttle opening TA is positive, it is determined whether or not the predetermined amount “ε” exceeds the positive side, and when it is negative, whether or not the predetermined amount “−ε” exceeds the negative side Judgment is sufficient. Therefore, the step such as step S209 is not provided in the flowchart of FIG.

In step S509, the control timing for changing the opening of the throttle valve 24 is changed. As a result, the first intake timing after the first ignition timing SA in one cylinder to be controlled (hereinafter referred to as “target cylinder”) in which the first ignition timing SA first appears after the determination in step S507. at the beginning of the stroke, the intake pressure of the intake port 22 of the target cylinder is required to reach the intake pressure corresponding to the throttle opening TA _t, opening degree variation of the throttle valve 24 is started is delayed. However, the pressure at the intake port 22 of the target cylinder referred to here may be the pressure at the most downstream point of the intake port 22. In this way, at the beginning of the first intake stroke of the first ignition timing after SA, the amount of air corresponding to the intake pressure corresponding to the required throttle opening TA _t is to begin is sucked into the combustion chamber 40. However, the opening degree change of the throttle valve 24 here is performed at the fastest and appropriate speed by the throttle actuator 30 as in the normal operation which is not the transient operation. Incidentally, during normal operation, the throttle opening degree TA is immediately controlled in response to changes in the accelerator opening degree so as to follow the required throttle opening TA _t.

  The ignition timing correction control and the throttle opening change timing change control in the second embodiment will be further described based on the conceptual diagram of FIG. In FIG. 6, only the opening period of the intake valve 34, that is, the intake stroke IN, the opening period of the exhaust valve 42, that is, the exhaust stroke EX, and the ignition timing SA are shown according to the flow of time for each cylinder, and are shown side by side. However, as described above, the engine 10 is an in-line four-cylinder internal combustion engine, the cylinder 26 at one end thereof is designated by # 1, and the cylinders up to the cylinder 26 at the other end are designated by # 2, # 3, and # 4 in order. Pointing. In FIG. 6, a part of each of the opening period of the intake valve 34 and the opening period of the exhaust valve 42 is depicted as overlapping, and in the following description based on FIG. It is assumed that the mechanism is in a controlled operating state. In FIG. 6, the ignition timing SA corrected by the above control is represented by a black circle, and the intake pressure or the exhaust pressure affected by changing the throttle opening or correcting the ignition timing SA. The intake strokes IN-7,8,9,10,11,12,13 or the exhaust strokes EX-7,8,9,10,11,12,13,14 that are related to the above are hatched.

At time t1 shown in FIG. 6, required throttle opening TA _t is derived (step S205 and step S505), the difference between its actual throttle opening TA is determined to be greater than a predetermined amount epsilon (step (Yes in S207 and Step S209, and Yes in Step S507), one target cylinder to be controlled is determined. As is apparent from FIG. 6, the target cylinder in which the first ignition timing SA first appears after the determination is the # 4 cylinder 26, and this cylinder is the target cylinder. And as already demonstrated based on FIG. 2, the first ignition timing SA-3 immediately after that is first correct | amended. In this case, since the required throttle opening TA _t is larger than the actual throttle opening degree TA, the first ignition timing SA-3 is retard correction (step S213). Then, the (first) ignition timings SA-4, 5, and 6 of the other cylinders that come after that are similarly retarded. Therefore, the exhaust pressure _PEM due to the exhaust gas exhausted in the exhaust strokes EX-7, 8, 9, 10 increases. However, the ignition timing SA-7, 8, 9, 10,... Of each cylinder after that is not retarded.

On the other hand, from the determination at time t1, at the start t2 of the first intake stroke IN-7 of the target cylinder after the initial ignition timing SA-3, the intake port 22 of the target cylinder (# 4 cylinder) is inhaled. as pressure reaches the intake pressure corresponding to the required throttle opening TA _t, opening degree variation of the throttle valve 24 is started. Changes in the throttle opening TA at this time, as described above, since takes place in and optimum speed fastest allowed the throttle actuator 30, since the derived requested throttle opening degree TA _t, throttle opening change Until it is started, the movement of the throttle valve 24 is generally interrupted. As the intake pressure of the intake port 22 of the target cylinder at time t2 reaches the intake pressure corresponding to the required throttle opening TA _t, results opening degree variation of the throttle valve 24 is performed, the intake stroke IN-7, 8, air amount of the intake air pressure commensurate with the 9, 10 in required throttle opening TA _t is obtained.

In this way, exhaust pressures EX-7, 8, 9, 10 that can cause an increase in exhaust pressure by correcting the retard of the ignition timing SA, and an increase in intake pressure by changing the throttle opening TA are controlled. Part of the intake strokes IN-7, 8, 9, and 10 in which a corresponding amount of air is obtained overlap and overlap each other. Therefore, the required throttle opening degree TA _t is transiently changed, even during transient operation of the opening degree of the throttle valve 24 is suddenly changed, more accurately, it is possible to obtain a proper internal EGR quantity. The increase in the exhaust pressure during the exhaust strokes EX-11, 12, 13, 14, etc. is due to the increase in the intake air amount corresponding to the intake pressure increased by changing the throttle opening TA. .

Incidentally, according to the above description of the second embodiment, the throttle opening increases, for example rapid acceleration, such as required throttle opening TA _t is conceptually described as being transiently increased, for example, rapid deceleration required throttle opening TA _t is the same even when reduced transiently. However, in this case, since the intake pressure _PIM decreases in response to the throttle opening TA becoming smaller, the ignition timing SA is advanced to correct the exhaust pressure _PEM correspondingly. . As a result, it is possible to prevent the overshoot occurs in the internal EGR amount r _e. Note that changing the timing of the change control of the throttle opening, even if the required throttle opening TA _t decreased transiently, even when the required throttle opening TA _t is transiently increased, the same (Fig. 5).

  As mentioned above, although this invention was demonstrated based on the said 1st and 2nd embodiment, this invention is not limited to this. In the first and second embodiments, the magnitude of the ignition retard amount or the ignition advance amount is simply set to be the same, but may be a variable. For example, based on the requested throttle opening, more specifically, based on the magnitude of the difference between the current throttle opening and the requested throttle opening, the greater the difference, the greater the correction amount. You may make it become. Note that when the corrected ignition timing is returned to the ignition timing that is not corrected, in the above description, the ignition timing is reset at once, but it may be returned in stages. In the second embodiment, the internal combustion engine to which the present invention is applied is an in-line four-cylinder internal combustion engine, but the number of cylinders of the internal combustion engine to which the present invention is applied, such as the first and second embodiments, The cylinder arrangement may be other than this. In the above description, the internal combustion engine is a port injection type internal combustion engine, but the present invention can be applied to various types of spark ignition type internal combustion engines such as an in-cylinder injection type.

  In the first and second embodiments, the intake / exhaust valves 34 and 42 are electromagnetically driven valves. For example, either or both of the intake and exhaust valves 34 and 42 are driven to open and close by a valve mechanism (VVT) including a camshaft that is driven to rotate by a timing belt in synchronization with the rotation of the crankshaft. Also good.

  In the first and second embodiments described above, the ignition timing is advanced or retarded to match the rise timing of the intake pressure and the exhaust pressure during transient operation, or the rise start timing, and more preferably. The throttle opening change timing is adjusted and controlled, but other operations may be performed. For example, the valve overlap period may be adjusted for this purpose.

  In the above embodiment, the present invention has been described with a certain degree of concreteness, but various modifications and changes can be made to the present invention without departing from the spirit and scope of the invention described in the claims. It must be understood that. That is, the present invention includes modifications and changes that fall within the scope and spirit of the appended claims and their equivalents.

1 is a conceptual diagram of a vehicle engine system to which a control device for an internal combustion engine according to a first embodiment is applied. It is an example of the control flowchart for ignition timing correction of 1st Embodiment. It is explanatory drawing for demonstrating the case where control of 1st Embodiment is not performed. It is explanatory drawing for demonstrating the case where control of 1st Embodiment is performed. It is an example of the control flowchart for throttle opening change timing control of 2nd Embodiment. It is a figure for demonstrating the correction control of the ignition timing of 2nd Embodiment, and the change control of the change timing of a throttle opening.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 14 Intake passage 24 Throttle valve 28 Accelerator pedal 30 Throttle actuator 32 Fuel injection valve 34 Intake valve 38 Spark plug 42 Exhaust valve 44 Exhaust passage

Claims (4)

A control device for an internal combustion engine that performs valve overlap control for overlapping a part of an open period of an intake valve and a part of an open period of an exhaust valve,
Valve overlap determining means for determining whether or not the valve overlap occurs;
Ignition means for igniting the mixture in the combustion chamber at a predetermined ignition timing;
A throttle valve for adjusting the amount of air sucked into the combustion chamber;
Required throttle opening degree derivation means for deriving a required throttle opening degree that is a target value of the throttle valve opening;
Requested throttle opening degree judging means for judging whether or not the requested throttle opening degree has changed transiently;
When it is determined by the valve overlap determining means that the valve overlap occurs, and when the required throttle opening determining means determines that the required throttle opening has changed transiently, the first after the determination time Correction means for correcting the ignition timing of the engine based on the required throttle opening,
Throttle opening control means for controlling the opening of the throttle valve to the required throttle opening derived by the required throttle opening deriving means ;
The internal combustion engine is a multi-cylinder internal combustion engine;
The throttle opening control means is determined by the valve overlap determining means that the valve overlap occurs, and the required throttle opening determining means is determined to have changed transiently. At the start of the first intake stroke after the first ignition timing, the intake port of the target cylinder in the one target cylinder to be controlled, in which the first ignition timing first appears after the determination time The throttle valve opening change is delayed and started so that the intake pressure reaches the intake pressure corresponding to the required throttle opening.
A control device for an internal combustion engine.   2. The control device for an internal combustion engine according to claim 1, wherein the correction unit corrects a delay of the initial ignition timing when the required throttle opening increases transiently. 3.   3. The control device for an internal combustion engine according to claim 1, wherein the correction means corrects the advance of the first ignition timing when the required throttle opening is transiently decreased. The control apparatus for an internal combustion engine according to any one of claims 1 to 3 , wherein an intake pressure of the intake port of the target cylinder is a pressure at a most downstream point of the intake port.

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