JP2011132935A - Control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine capable of more early starting ignition and fuel injection by synchronous control after an engine is started. <P>SOLUTION: An electronic control unit 1 determines a crank angle according to the detection of a missing tooth of a crank rotor 2 by a crank angle sensor 3, and determines a crank angle according to the detection result of a projection and a recess pattern of a cam rotor 4 by a cam angle sensor 5. The electronic control unit 1 estimates the determination time of the crank angle depending on the former according to the determination of the crank angle depending on the latter. A cylinder which first enters ignition timing after the estimated determination time of the crank angle is set as an ignition start enable cylinder which performs first ignition after the engine is started. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an internal combustion engine control apparatus, and more particularly to an improvement in a control structure related to determination of an ignition startable cylinder at the time of engine start.

  In an on-board internal combustion engine, the crank angle is determined after the engine is started, and after the current crank angle is recognized, control of fuel injection and ignition synchronized with the crank angle is started. The determination of the crank angle, that is, the discrimination of the ignition cylinder, is performed in accordance with 1) detection of the missing teeth of the crank rotor by the crank angle sensor, or 2) according to the detection result of the uneven pattern of the cam rotor by the cam angle sensor. I have to.

  In the worst case, the determination of the crank angle according to the above 1) may not be performed until the crankshaft rotates once. On the other hand, the determination of the crank angle according to 2) can be performed more quickly in many cases. However, the determination result of the crank angle according to 2) above may be accompanied by errors due to camshaft and timing belt / chain assembly tolerances, which is inaccurate compared to the determination result of the crank angle according to 1) above. It has become. Therefore, engine control that requires strict management of the crank angle at the control timing, such as ignition timing control, cannot be performed until the crank angle is determined according to 1) above. In addition, since a certain amount of time is required from the time of fuel injection and the setting of the required ignition timing to the time of actual ignition, such control is immediately started even after the crank angle is completely determined. I can't.

  Therefore, conventionally, as seen in Patent Document 1, immediately after the engine is started, ignition and fuel injection are performed by asynchronous control, and after the crank angle is determined, the control is sequentially switched to synchronous control. ing. That is, until the crank angle is completely determined, fuel injection and ignition are performed without specifying the ignition cylinder. According to the implementation of such asynchronous control, the first explosion can be started without waiting for the crank angle to be determined, so that the engine can be started early.

Japanese Patent Laid-Open No. 06-185387

  However, when asynchronous control is employed for fuel injection or ignition immediately after the engine is started, two types of control of asynchronous control and synchronous control are mixed. For this reason, it is necessary to individually perform adjustments related to ensuring fuel efficiency and exhaust emission performance for both controls, resulting in an increase in the number of man-hours for the adjustment work. In addition, with asynchronous control, the timing of fuel injection and ignition cannot be precisely controlled, making it difficult to ensure sufficient fuel efficiency and exhaust emission performance.

  The present invention has been made in view of such circumstances, and a problem to be solved is an internal combustion engine control apparatus capable of starting ignition and fuel injection by synchronous control after engine start earlier. Is to provide.

  In order to solve the above-mentioned problem, the invention according to claim 1 as a control device for an internal combustion engine includes a first determination means for determining a crank angle in accordance with detection of a missing tooth of a crank rotor by a crank angle sensor, and a cam There are provided two determination means, a second determination means for determining the crank angle according to the detection result of the concave / convex pattern of the cam rotor by the angle sensor. Here, the second determinator can perform the determination earlier than the first determinator, but the accuracy of the determination result is inferior. Therefore, engine control that requires the strict management of the crank angle at the control timing, such as the ignition timing and the fuel injection synchronous control, cannot be started until the determination of the crank angle by the first determining means is completed. .

  However, even if the determination of the crank angle by the first determination means is completed, a certain time margin is required from the request for ignition or fuel injection to the execution. That is, it is necessary to make a request for ignition or fuel injection at a time earlier than its implementation by a certain period. For this reason, the start of synchronous control of ignition and fuel injection cannot be performed immediately after the crank angle is determined.

  In this regard, according to the present invention, in accordance with the determination of the crank angle by the second determination means, the prediction means for predicting the determination timing of the crank angle by the first determination means, and the determination of the crank angle predicted by the prediction means Setting means is provided for setting a cylinder that first reaches the ignition timing after the timing as an ignition startable cylinder that performs initial ignition after engine start. Although the crank angle determined by the second determining means may include some errors, it is possible to confirm the approximate crank angle from the result. For this reason, it is possible to determine the approximate timing at which the crank angle is determined by the first determination means from the determination result of the crank angle by the second determination means. As a result, after the crank angle is determined by the first determination means, It becomes possible to specify the cylinder that reaches the ignition timing first. If the cylinder to be ignited is known, it is possible to perform ignition request and fuel injection in advance even if the exact crank angle is not determined. If the ignition request and the fuel injection are performed in this way, it becomes possible to perform ignition for the cylinder that first reaches the ignition timing after the crank angle is determined based on the completely determined crank angle. Therefore, in the control device for an internal combustion engine of the present invention, after the crank angle is determined according to the detection of the missing teeth of the crank rotor, it is possible to start the fuel injection and the synchronous control of the ignition from the cylinder that first reaches the ignition timing. Become. Therefore, according to the present invention, it becomes possible to start ignition and fuel injection by synchronous control after engine startup earlier.

  In the control apparatus for an internal combustion engine according to the present invention, since synchronous control of fuel injection and ignition can be started from an early stage, the setting means is used as the first fuel injection after engine start, according to claim 2. As a result, it is possible to perform synchronous injection for the cylinder set as the ignition startable cylinder. That is, it becomes possible to perform synchronous injection from the beginning without performing asynchronous injection. In this case, since asynchronous injection can be abolished, the fuel injection control method can be limited to only synchronous injection, and the adaptation work can be reduced. In addition, since asynchronous injection in which precise control of fuel injection timing is impossible can be abolished, fuel consumption performance and exhaust emission performance can be improved.

  By the way, depending on the timing at which the synchronous injection is started, the request start time may already have passed when the request injection start time is set. In such a case, fuel injection cannot be performed at an appropriate timing at the time of the first explosion with poor combustion conditions. Therefore, in such a case, it is desirable to delay the start of the first explosion by one cylinder rather than forcibly injecting the fuel to make the first explosion more reliable. On the other hand, after the start of the first explosion, if the fuel injection is stopped because the required injection start timing cannot be satisfied, the combustion becomes discontinuous. It is desirable to force it. Therefore, according to claim 3, when the required start timing has already passed when the required injection start timing is set, if the fuel injection is the first injection after the engine is started, the fuel injection to the cylinder is prohibited. If this is not the case, if the fuel injection into the cylinder is immediately performed, it is possible to avoid the discontinuous combustion while ensuring the initial explosion.

  Depending on the control device of the internal combustion engine, a first counter that is counted up every time a crank signal is output from the crank angle sensor may be used as a counter for measuring the timing of engine control synchronized with the crank angle such as fuel injection or ignition. And a second counter that is counted up every time the crank signal is output a plurality of times. Based on the first counter, it is possible to manage the crank angle more precisely, and it is possible to accurately perform the crank angle synchronization control even at the time of engine start where engine rotation is unstable. However, if the engine speed increases, the frequency of interrupts associated with the count-up of the first counter increases, and if the interrupt process for fuel injection or ignition is performed each time, the computation load of the control device will be excessive. turn into. In this respect, as in claim 4, when the engine speed is low, engine control synchronized with the crank angle is performed based on the first counter, and when the engine speed is high, the crank control is performed based on the second counter. If engine control is performed in synchronization with the angle, the crank angle synchronization control is accurately performed even when the internal combustion engine is unstable and the engine rotation is low, while avoiding an increase in calculation load when the engine speed increases. Can be performed.

By the way, in the control apparatus for an internal combustion engine, a SAC (sensor / actuator controller) that performs lower-level processing closely related to hardware, and a higher-level control setting such as a fuel injection amount, an injection start timing, an ignition timing, and the like. The engine control program module may be divided into APL (application) for processing. According to such a control structure, the versatility of the control program is enhanced. That is, a common APL can be made to correspond to a plurality of types of hardware by absorbing individual differences in hardware with the SAC. For example, fuel injection and ignition crank angle synchronous control
A crank SAC that processes the detection signal of the crank angle sensor.
-Ignition APL that sets the ignition timing according to engine operating conditions.
An ignition SAC that controls the spark plug so that ignition is performed at the ignition timing set by the ignition APL.
An injection APL that sets the fuel injection amount and fuel injection timing according to the engine operating state.
An injection SAC that controls the injector so that the fuel injection of the fuel injection amount set by the injection APL is performed at the fuel injection timing set by the injection APL. It can be performed by each module.

In such a case, as in claim 5,
The function of performing the processing of the first and second determining means and the function of performing the processing of the predicting means are arranged in the crank SAC.
A function for performing the processing of the setting means is arranged in the ignition SAC.
A function for performing the process of setting the ignition startable cylinder set by the setting means as a cylinder for performing the first injection after the engine start is arranged in the injection SAC. As a result, the related functions can be aggregated to increase the independence of each module, and the versatility of the control program can be further enhanced. For example, when each module is configured as described above, a difference in the initial ignition timing between an eco-run vehicle and a vehicle that is not so can be handled only by changing the ignition SAC. Further, when each module is configured as described above, the difference in the number of cylinders can be handled only by changing the crank SAC.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows typically the whole structure of the control apparatus of the internal combustion engine about one Embodiment of this invention. FIG. 4A is a plan view showing a planar structure of a crank rotor, and FIG. The time chart which shows the output mode of the crank signal and cam signal in the embodiment. The time chart which shows the control aspect at the time of engine starting in the embodiment. The time chart which shows the control aspect when the request | requirement injection start timing of the ignition start possible cylinder has already passed when the 10CA crank counter is determined in the same embodiment. The flowchart which shows the process sequence of the ignition start possible cylinder determination routine employ | adopted as the same embodiment. The flowchart which shows the process sequence of the fuel-injection control routine employ | adopted as the same embodiment. The block diagram which shows typically the control structure of the control apparatus of the conventional internal combustion engine. The block diagram which shows typically the control structure of the control apparatus of the internal combustion engine of the said embodiment.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a control device for an internal combustion engine according to the present invention will be described in detail with reference to FIGS.
FIG. 1 shows the overall structure of a control device for an internal combustion engine according to this embodiment. As shown in FIG. 1, the control device for an internal combustion engine of the present embodiment is configured around an electronic control unit 1.

  The electronic control unit 1 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output port (I / O). The CPU performs various arithmetic processes related to engine control. The ROM stores a program and data for engine control. The RAM temporarily stores CPU calculation results, sensor detection results, and the like. I / O mediates transmission and reception of signals with the outside.

  In the input port of the electronic control unit 1, there are a crank angle sensor 3 that outputs an edge signal according to the passage of teeth provided on the outer periphery of the crank rotor 2, and an uneven passage provided on the outer periphery of the cam rotor 4. Accordingly, a cam angle sensor 5 that outputs an edge signal is connected. In addition, detection signals of various sensors that detect engine operating conditions such as an accelerator sensor and an air flow meter are input to the input port of the electronic control unit 1.

  On the other hand, the output port of the electronic control unit 1 is connected to drive circuits for various actuators installed in the internal combustion engine, including an injector drive circuit 6 and a spark plug drive circuit 7. The injector drive circuit 6 causes the injectors 8 of each cylinder to perform fuel injection in accordance with the fuel injection amount output from the electronic control unit 1 and the fuel injection timing command signal. The spark plug drive circuit 7 causes the spark plug 9 of each cylinder to perform ignition in accordance with an ignition timing command signal output from the electronic control unit 1.

  FIG. 2A shows the structure of the crank rotor 2 employed in the present embodiment. As shown in the figure, teeth are provided on the outer periphery of the crank rotor 2 every 10 ° CA. Further, a chipped tooth of 30 ° CA is provided on the outer periphery of the crank rotor 2.

  FIG. 2B shows the structure of the cam rotor 4 employed in the present embodiment. As shown in the figure, a plurality of irregularities are formed on the outer periphery of the cam rotor 4 at unequal pitches. On the outer periphery of the cam rotor 4 in the figure, a convex portion for 60 ° CA, a concave portion for 120 ° CA, a convex portion for 180 ° CA, a concave portion for 60 ° CA, a convex portion for 160 ° CA, 140 The concave portions for CA are formed in the clockwise order.

  FIG. 3 shows how the crank angle sensor 3 and the cam angle sensor 5 output signals. Note that the crank signal and cam signal shown in the figure are obtained by shaping the output signals of the crank angle sensor 3 and the cam angle sensor 5.

  After the engine is started, the electronic control unit 1 determines the crank angle based on these crank signal and cam signal. The determination of the crank angle can be performed based on both 1) the detection of missing teeth of the crank rotor 2 and 2) the uneven pattern of the cam rotor 4. The determination of the crank angle according to the above 1) is performed depending on whether the cam angle sensor 5 outputs a convex signal or a concave signal when a missing tooth of the crank rotor 2 is detected. In addition, the determination of the crank angle according to 2) is performed based on the detected length (crank angle) of the unevenness detection period of the cam rotor 4.

  The electronic control unit 1 generates the following two counters as counters used for checking the control timing based on signals from the crank angle sensor 3 and the cam angle sensor 5. That is, the electronic control unit 1 generates a 10CA crank counter that is counted up every 10 ° CA and a 30CA crank counter that is counted up every 30 ° CA. Here, the 10CA crank counter is generated based on the crank angle determined in the above 2). On the other hand, the 30CA crank counter is generated based on the crank angle determined in the above 1).

  By the way, in the worst case, the determination of the crank angle based on the detection of the missing teeth of the crank rotor 2 in 1) may not be performed until the crankshaft rotates once. On the other hand, the determination of the crank angle based on the uneven pattern of the cam rotor 4 in 2) can be performed at the time when the crankshaft rotates 180 ° CA at the maximum. Therefore, in general, the determination of the crank angle according to 2) can be performed earlier than the determination of the crank angle according to 1).

  However, the crank angle determined based on the uneven pattern of the cam rotor 4 has an error of about 10 ° CA due to the assembly tolerance of the camshaft and timing belt / chain. Therefore, although the 10CA crank counter can be determined earlier than the 30CA crank counter, its accuracy is inferior. Therefore, it is necessary to perform engine control, such as the synchronous control of ignition, that needs to strictly manage the crank angle of the control timing based on a more accurate 30CA crank counter. Therefore, it is necessary to wait for the start of the ignition synchronous control until the complete crank angle is determined by detecting the missing teeth of the crank rotor 2.

  On the other hand, for the ignition by the synchronous control, it is necessary to perform the fuel injection and set the timer to the spark plug drive circuit 7 prior to that. Therefore, even if preparation for synchronous control of ignition is started after the complete crank angle is determined by detecting the missing teeth of the crank rotor 2, the ignition by the synchronous control can actually be started after a while. It becomes from.

  Here, according to the 10CA crank counter, although there is certainly an error, the approximate crank angle can be known from the value. Therefore, from the 10CA crank counter, it is possible to predict the approximate time when the 30CA crank counter is determined. Therefore, in this embodiment, when the 10CA crank counter is determined, the determination timing of the 30CA crank counter is predicted, and the synchronous control of ignition is started from the cylinder that first reaches the ignition timing after the predicted determination time. I'm trying to start preparation. In other words, in the present embodiment, the cylinder that reaches the ignition timing first after the 30 CA crank counter is predicted, which is predicted when the 10 CA crank counter is determined, is set as an ignition startable cylinder that performs the first ignition after the engine is started. Yes. The fuel injection and ignition timer for the cylinder are set before the 30CA crank counter is determined. The fuel injection at this time is performed only for the target cylinder. That is, in this embodiment, synchronous injection is performed from the beginning without performing asynchronous injection.

  FIG. 4 shows a control mode at the time of engine start of the control apparatus for an internal combustion engine of the present embodiment. As described above, when the 10CA crank counter is fixed, the fixed time of the 30CA crank counter is predicted. After that predicted timing, the cylinder that first reaches the ignition timing of BTDC 30 ° CA is set as the ignition start cylinder that performs the first ignition after the engine is started. In the figure, the third cylinder is set as a cylinder capable of starting ignition. When the ignition startable cylinder is set in this manner, the electronic control unit 1 performs fuel injection for the cylinder and sets the ignition timer of the spark plug drive circuit 7 in time for the ignition timing. As a result, in the third cylinder set as the ignition startable cylinder, the first explosion is performed immediately after the 30CA crank counter is determined. Thereafter, synchronous injection and synchronous ignition are carried out in order of the ignition timing.

  By the way, depending on the interval from the determination of the 10CA crank counter to the determination of the 30CA crank counter, the start timing of fuel injection for that cylinder may have already passed when the ignition startable cylinder is set. In this case, since fuel injection cannot be performed at an appropriate time, it is desirable to delay the start of the first explosion by one cylinder rather than forcibly injecting the fuel to make the initial explosion more reliable. On the other hand, after the start of the first explosion, if the fuel injection is stopped because the required injection start timing cannot be satisfied, the combustion becomes discontinuous. It is desirable to force it. Therefore, in the present embodiment, when the required start timing has already passed when the required injection start timing is set, if the fuel injection is the first injection after the engine is started, the fuel injection to the cylinder is prohibited, Otherwise, the fuel injection into the cylinder is performed immediately. As a result, discontinuous combustion is avoided while ensuring the first explosion.

  For example, in the case of FIG. 5, when the 10CA crank counter is determined, the third cylinder is set as a cylinder capable of starting ignition. However, at that time, the required injection start timing for the cylinder has already passed, and it is certain that the required injection start timing cannot be observed. Therefore, in this case, the fuel injection to the third cylinder is stopped, and then the fuel injection is started from the fourth cylinder that reaches the ignition timing.

  In the present embodiment, as described above, the electronic control unit 1 generates two counters, a 10 CA crank counter and a 30 CA crank counter, as counters used for checking the control timing. Here, based on the 10CA crank counter, it is possible to perform more precise control of the crank angle, and it is possible to accurately perform the crank angle synchronization control even when the engine starts with unstable engine rotation. . However, if the engine speed increases, the frequency of interrupts associated with the 10CA crank counter count-up increases, and if the interrupt process for fuel injection or ignition is performed each time, the computation load on the control device becomes excessive. End up.

  Therefore, in the present embodiment, when the engine speed is low, engine control synchronized with the crank angle is performed based on the 10CA crank counter, and when the engine speed is high, the engine synchronized with the crank angle based on the 30CA crank counter. Control is implemented. As a result, while avoiding an increase in calculation load when the engine rotational speed increases, it is possible to precisely perform crank angle synchronization control even when the internal combustion engine with unstable engine rotation is low. Specifically, a 10CA crank counter is used as a counter used for determining control timing until the engine speed exceeds a predetermined switching determination value, and a 30CA crank counter is used after the switching determination value is exceeded. I have to. However, even after switching to the 30CA crank counter, if the engine speed is below the switching determination value, the counter to be used is immediately returned to the 10CA crank counter.

  FIG. 6 shows a flowchart of an ignition startable cylinder determination routine employed in the present embodiment. This routine is executed by the electronic control unit 1 every time the 10CA crank counter is counted up after the engine is started.

  When this routine is started, the electronic control unit 1 first checks in step S100 whether or not it is the moment when the 10CA crank counter is determined. Here, if it is not a fixed moment (S100: NO), the electronic control unit 1 ends the processing of this routine as it is.

  On the other hand, if it is the moment of determination (S100: YES), the electronic control unit 1 predicts the determination timing of the 30CA crank counter from the determined value of the 10CA crank counter in step S101. Then, in the subsequent step S102, the electronic control unit 1 sets the cylinder that first reaches the ignition timing after the predicted timing of the 30CA crank counter as the cylinder capable of starting ignition, and ends the processing of this routine.

  FIG. 7 shows a flowchart of a fuel injection control routine employed in the present embodiment. This routine is also executed by the electronic control unit 1 every time the 10CA crank counter is counted up after the engine is started.

  When this routine is started, the electronic control unit 1 first checks in step S200 whether or not the engine speed exceeds a prescribed switching determination value. Here, if the engine speed exceeds the switching determination value (S200: YES), the electronic control unit 1 uses the 30CA crank counter as a counter used for determining the control timing (S201), otherwise (S201). (S200: NO) A 10CA crank counter is used (S202).

  Subsequently, the electronic control unit 1 acquires the required injection timing in step S203, and checks in step S204 whether or not the next cylinder that reaches the ignition timing is an ignitable cylinder. The electronic control unit 1 proceeds to step S205 if the cylinder that will reach the next ignition timing is an ignitable cylinder, and otherwise ends the processing of this routine as it is (S204: NO).

  In step S205, the electronic control unit 1 checks whether or not the required injection start timing of the cylinder that will reach the next ignition timing is already in the past. Here, if the required injection start time is not in the past (S205: NO), the electronic control unit 1 checks in step S209 whether or not the current control cycle is the timing immediately before the injection start time. If so, the fuel injection is performed by calculating the injection amount (S210) and setting the timer (S211).

  On the other hand, if the required injection start time is already in the past (S205: YES), the electronic control unit 1 checks in step S206 whether or not the current injection is the first injection at the time of engine start. If this is the first injection (S206: YES), the electronic control unit 1 stops the injection this time and ends the processing of this routine as it is. On the other hand, if it is not the first injection (S207: NO), the electronic control unit 1 calculates the injection amount in step S207, immediately starts injection in step S208, and ends the processing of this routine. To do.

  The engine control program stored in the electronic control unit 1 that performs such processing is constituted by a number of modules. Such modules include an APL (application) that performs higher-level processing such as setting the engine control amount, and a SAC (sensor / actuator controller) that performs lower-level processing such as hardware drive control such as sensors and actuators. ing. For example, a module that performs processing related to fuel injection includes an injection APL that sets an injection amount and an injection timing, and an injection SAC that drives and controls the injector 8 according to the injection amount and injection timing set by the injection APL. It has been. As a module for performing processing related to ignition, there are provided an ignition APL for setting the ignition timing and an ignition SAC for driving and controlling the spark plug 9 so that ignition is performed at the timing set by the ignition APL. ing. Furthermore, the control device for the internal combustion engine of the present embodiment is provided with a crank SAC for processing signals of the crank angle sensor 3 and the cam angle sensor 5.

  FIG. 8 shows a control structure of a conventional control device for an internal combustion engine. As shown in the figure, the control device includes an injection APL, an injection SAC, an ignition APL, an ignition SAC, and a crank SAC as modules relating to fuel injection and ignition. Here, in the conventional control device, generation of the 10CA crank counter and the 30CA crank counter is performed by the crank SAC. The injection APL is responsible for determining the cylinder that can be injected for the first time, confirming the determined position of the 30CA crank counter, and setting the energization start timing for the first ignition.

  In such a case, if there is a difference in the initial ignition timing between the eco-run car that performs automatic idle stop and the car that does not, it is necessary to change the setting mode of the initial ignition energization start time, in addition to the ignition system module, The injection APL also needs to be different. If there is a difference in the number of cylinders of the applied internal combustion engine, it is necessary to change the confirmation mode of the fixed position of the 30CA crank counter and the determination mode of the cylinders that can be injected for the first time. Therefore, in addition to the crank SAC, the injection APL is also different. It is necessary to.

  As described above, in the control device for the conventional internal combustion engine, the control component needs to be significantly modified according to the hardware change, and the versatility is poor. Therefore, in this embodiment, the control structure is highly versatile by reviewing the arrangement of functions in each module.

  FIG. 9 shows a control structure of the control device for the internal combustion engine of the present embodiment. As shown in the figure, the present embodiment also includes an injection APL, an injection SAC, an ignition APL, an ignition SAC, and a crank SAC as modules relating to fuel injection and ignition. However, in the present embodiment, a function related to the prediction of the determination timing of the 30CA crank counter is arranged in the crank SAC, and a function related to determination of the ignitable cylinder is arranged in the ignition SAC. In addition, a function related to the determination of the first-injectable cylinder is arranged in the injection SAC.

  In this embodiment, the difference in the setting mode of the initial ignition energization start timing due to the difference in initial ignition timing can be absorbed only by changing the ignition SAC. Further, the difference in the relationship between the fixed timing of the 10CA crank counter and the missing tooth position due to the difference in the number of cylinders can be absorbed only by changing the crank SAC. As described above, in the control structure adopted by the present embodiment, the independence of each module is improved by improving the functional arrangement, so that it is possible to cope with hardware changes with relatively few control component modifications. It can be done.

  In the above-described embodiment, the electronic control unit 1 is configured to perform the processes of the first and second determination means, the prediction means, and the setting means. In this embodiment, the 30CA crank counter corresponds to the first counter, and the 10CA crank counter corresponds to the second counter.

According to the control apparatus for an internal combustion engine of the present embodiment as described above, the following effects can be obtained.
(1) In the present embodiment, the electronic control unit 1 predicts the determination timing of the 30CA crank counter according to the determination of the 10CA crank counter, and the cylinder that first reaches the ignition timing after the predicted determination timing is selected. The cylinder is set as an ignition startable cylinder that performs the first ignition after the engine is started. The 10CA crank counter may contain some errors, but it is possible to confirm the approximate crank angle from the result. Therefore, from the value of the 10CA crank counter, it is possible to determine the approximate timing when the 30CA crank counter is determined, and thus it is possible to identify the cylinder that first reaches the ignition timing after the 30CA crank counter is determined. If the cylinder to be ignited is known, it is possible to perform ignition request and fuel injection in advance even if the exact crank angle is not determined. If the ignition request and the fuel injection are performed in this way, it becomes possible to perform ignition for the cylinder that first reaches the ignition timing after the crank angle is determined based on the completely determined crank angle. Therefore, in the control apparatus for the internal combustion engine of the present embodiment, after the crank angle is determined according to the detection of the missing teeth of the crank rotor 2, the fuel injection and the ignition synchronous control are started from the cylinder that first reaches the ignition timing. Is possible. Therefore, according to the present embodiment, it becomes possible to start ignition and fuel injection by synchronous control after engine startup earlier.

  (2) In the present embodiment, as the first fuel injection after the engine is started, the synchronous injection is performed on the cylinder set as the ignition startable cylinder. That is, in this embodiment, synchronous injection is performed from the beginning without performing asynchronous injection. If the asynchronous injection is abolished in this way, the fuel injection control method can be limited to only synchronous injection, and the adaptation work can be reduced. In addition, since asynchronous injection, which cannot precisely control the fuel injection timing, has been abolished, fuel efficiency and exhaust emission performance can be improved.

  (3) In the present embodiment, when the required start timing has already passed when the required injection start timing is set, if the fuel injection is the first injection after engine start, fuel injection into that cylinder is prohibited. If not, the fuel injection to the cylinder is immediately performed. Depending on the timing at which the synchronous injection is started, the required start timing may already have passed when the required injection start timing is set. In such a case, fuel injection cannot be performed at an appropriate timing at the time of the first explosion with poor combustion conditions. Therefore, in such a case, it is desirable to delay the start of the first explosion by one cylinder rather than forcibly injecting the fuel to make the first explosion more reliable. On the other hand, after the start of the first explosion, if the fuel injection is stopped because the required injection start timing cannot be satisfied, the combustion becomes discontinuous. It is desirable to force it. Therefore, according to the present embodiment, it is possible to avoid discontinuous combustion while ensuring the initial explosion.

  (4) In the present embodiment, two counters having different count-up cycles, ie, a 10CA crank counter and a 30CA crank counter, are generated as counters used for determining the control timing. Based on the 10CA crank counter with a finer count-up cycle, it is possible to manage the crank angle more precisely. In particular, even when the engine starts unstable, the crank angle synchronization control is accurately performed. It becomes possible. On the other hand, when the engine speed increases, the frequency of interruptions associated with the count-up of the 10CA crank counter increases, and each time an interruption process for fuel injection or ignition is performed, the computation load on the control device becomes excessive. End up. In this regard, in the present embodiment, when the engine speed is low, engine control synchronized with the crank angle is performed based on the 10CA crank counter, and when the engine speed is high, synchronized with the crank angle based on the 30CA crank counter. The engine control is carried out. Therefore, it is possible to accurately perform the crank angle synchronization control even at the time of low rotation of the internal combustion engine where the engine rotation is unstable while avoiding an increase in calculation load when the engine rotation speed increases.

  (5) In the present embodiment, functions related to the generation of both the 10CA and 30CA crank counters and the prediction of the determined timing of the 30CA crank counter are arranged in the crank SAC. Further, in the present embodiment, the ignition SAC has a function of setting the cylinder that first reaches the ignition timing after the predicted timing of the 30CA crank counter as the ignition startable cylinder that performs the first ignition after the engine start. Each of the injection SACs has a function of performing a process of setting the set ignition startable cylinder as a cylinder for performing the first injection after the engine is started. Therefore, related functions can be aggregated to increase the independence of each module, and the versatility of the control program can be further enhanced.

In addition, the said embodiment can also be changed and implemented as follows.
In the above embodiment, two counters are used as a counter used for determining the control timing: a 10CA crank counter that is counted up every 10 ° CA and a 30CA crank counter that is counted up every 30 ° CA. I was trying to do it. The count-up cycle of these counters is not limited to this, and may be changed as appropriate.

  In the above embodiment, the control structure as shown in FIG. 9 is adopted, but it is not necessary to consider the diversion of control components, such as when the applied hardware configuration is narrowed down However, other control structures may be adopted.

  -In the above embodiment, the counter used for engine control synchronized with the crank angle is properly used according to the engine rotation speed. However, only one of the counters is sufficient without excessive computation load. If the control can be performed with high accuracy, it is possible not to use such a counter properly.

  In the above embodiment, when the required injection start time has already elapsed, if the required fuel injection is the first injection after engine startup, fuel injection into that cylinder is prohibited. Otherwise, the fuel injection into the cylinder was immediately performed. Of course, if the initial explosion can be reliably performed even if the injection timing is slightly shifted, the postponement of the initial injection due to the passage of the request start timing may not be adopted. In addition, even after the first explosion, if misfire occurs when the injection timing is deviated, the injection after the initial injection may be postponed due to the passage of the request start timing.

  In the above embodiment, asynchronous injection is abolished by performing synchronous injection for a cylinder set as an ignition startable cylinder as the first fuel injection after engine startup. However, if necessary, asynchronous injection may be performed before the start of synchronous injection.

  DESCRIPTION OF SYMBOLS 1 ... Electronic control unit, 2 ... Crank rotor, 3 ... Crank angle sensor, 4 ... Cam rotor, 5 ... Cam angle sensor, 6 ... Injector drive circuit, 7 ... Spark plug drive circuit, 8 ... Injector, 9 ... Spark plug

Claims (5)

First determining means for determining a crank angle in response to detection of a missing tooth of the crank rotor by a crank angle sensor;
A second determining means for determining a crank angle in accordance with a detection result of the uneven pattern of the cam rotor by the cam angle sensor;
Predicting means for predicting the determination timing of the crank angle by the first determining means in response to the determination of the crank angle by the second determining means;
A setting means for setting a cylinder that first reaches the ignition timing after the determined timing of the crank angle predicted by the prediction means as an ignition startable cylinder that performs the first ignition after the engine start;
A control device for an internal combustion engine. The control apparatus for an internal combustion engine according to claim 1, wherein the first fuel injection after the engine is started performs synchronous injection for a cylinder set by the setting means as an ignition startable cylinder. When setting the required injection start time for a specific cylinder and the required start time has already passed, if the fuel injection is the first injection after engine start, fuel injection into that cylinder is prohibited. If not, the control device for the internal combustion engine according to claim 1 or 2, wherein the fuel injection to the cylinder is immediately performed. A first counter that counts up each time the crank signal is output from the crank angle sensor that outputs a crank signal at every fixed crank angle, and a second counter that counts up every time the crank signal is output a plurality of times. A counter, and
When the engine speed is low, engine control synchronized with the crank angle is performed based on the first counter, and when the engine speed is high, engine control synchronized with the crank angle is performed based on the second counter. The control device for an internal combustion engine according to any one of claims 1 to 3. The control device ignites the crank SAC for processing the detection signal of the crank angle sensor, the ignition APL for setting the ignition timing according to the engine operating state, and the ignition timing set by the ignition APL. The ignition SAC for controlling the spark plug, the injection APL for setting the fuel injection amount and the injection timing according to the engine operating state, and the fuel injection of the same injection amount set at the injection timing set by the injection APL And an injection SAC that controls the injector so that the engine control program is performed.
A function of performing the processing of the first and second determining means and a function of performing the processing of the prediction means are arranged in the crank SAC;
A function for performing the processing of the setting means is disposed in the ignition SAC,
The internal combustion engine according to any one of claims 1 to 4, wherein a function of performing a process of setting the ignition startable cylinder set by the setting means as a cylinder for performing initial injection after engine startup is arranged in the injection SAC. Control device.

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