JP4438537B2 - Ignition timing control device for spark ignition internal combustion engine - Google Patents

Description

  The present invention relates to an ignition timing control device for a spark ignition type internal combustion engine.

  During engine low-load operation, some cylinders are operated with some cylinders stopped and the remaining cylinders are operated with reduced cylinder operation, and during engine high-load operations, all cylinders are operated with all cylinders. Conventionally known internal combustion engines are known. In this way, fuel consumption can be reduced.

  However, when the reduced-cylinder operation is switched to the all-cylinder operation, the generated torque increases significantly, that is, a torque shock may occur, and thus drivability may deteriorate.

  Therefore, when switching from reduced-cylinder operation to full-cylinder operation, the ignition timing of the cylinder that has been restarted is temporarily set to the retard side of the ignition timing of the cylinder that has been continuously operated. A spark ignition type internal combustion engine is known (see Patent Documents 1 and 3). When the ignition timing is retarded, the generated torque in the cylinder is suppressed, and thus the increase in the generated torque in the entire engine is suppressed.

JP-A-8-105337 Japanese Patent Laid-Open No. 5-180135 JP 63-1759 A

  However, for example, when switching from reduced-cylinder operation to all-cylinder operation due to engine rapid acceleration operation, the generated torque must be significantly increased. Nevertheless, the above-described internal combustion engine has a problem in that the generated torque is suppressed in the cylinder in which the operation has been resumed, thus causing a so-called torque shortage.

  Accordingly, an object of the present invention is to provide an ignition timing control device for an internal combustion engine that can obtain good acceleration performance.

In order to solve the above-described problems, according to the present invention, a reduced-cylinder operation in which operation is stopped in a part of a plurality of cylinders and operation is performed in the remaining cylinders, and an all-cylinder operation in which operation is performed in all cylinders. In a spark ignition type internal combustion engine capable of switching the engine, when the reduced-cylinder operation is switched to the all-cylinder operation, the operation is continued at the ignition timing of the some cylinders at which the operation is resumed at this time. An ignition timing control device that is temporarily set to an advance side with respect to the ignition timing of the remaining cylinders, and when the engine slow acceleration operation is performed and the reduced cylinder operation is switched to the all cylinder operation, The ignition timing of some of the cylinders that are restarted is temporarily set to the retard side of the ignition timing of the remaining cylinders that are continuously operated, and engine rapid acceleration operation is performed. When switching from reduced-cylinder operation to full-cylinder operation, Wherein the ignition timing of some of the cylinders which come operation is resumed, is set to temporarily advance side of the ignition timing of the remaining cylinders operation is continuously performed.

  Good acceleration performance can be obtained.

  Referring to FIG. 1, the engine body 1 includes two banks 1a and 1b. Each bank 1a and 1b has, for example, three cylinders 2a and 2b, respectively. These cylinders 2 a and 2 b are connected to a surge tank 4 through corresponding intake branch pipes 3, and the surge tank 4 is connected to an air cleaner 6 through an intake duct 5. A throttle valve 8 driven by a step motor 7 is disposed in the intake duct 5. On the other hand, the cylinder 2a of the bank 1a is connected to the catalytic converter 10a via the exhaust manifold 9a, and the cylinder 2b of the bank 1b is connected to the catalytic converter 10b via the exhaust manifold 9b. The catalytic converters 10a and 10b are connected to the catalytic converter 12 through a common exhaust pipe 11. For example, a three-way catalyst is accommodated in the catalytic converters 10a, 10b, and 12. The cylinders 2a and 2b are provided with a fuel injection valve 13 and a spark plug 14, respectively.

  The electronic control unit 30 is composed of a digital computer, and is connected to each other by a bidirectional bus 31. 35, an input port 36 and an output port 37. Water temperature sensors 40a and 40b for detecting the cooling water temperatures THWa and THWb of the banks 1a and 1b are respectively attached to the banks 1a and 1b, and an air flow meter 41 for detecting the intake air mass flow rate Ga is attached to the intake duct 5. It is attached. Further, a depression amount sensor 43 for detecting a depression amount DEP of the accelerator pedal 42 is connected to the accelerator pedal 42. The output voltages of these sensors 40a, 40b, 41, and 43 are input to the input ports 36 via the corresponding AD converters 38, respectively. Further, a crank angle sensor 44 that generates an output pulse every time the crankshaft rotates, for example, 10 ° is connected to the input port 36. The CPU 34 calculates the engine speed NE based on this output pulse. On the other hand, the output port 37 is connected to the step motor 7, the fuel injection valve 13, and the spark plug 14 via the corresponding drive circuit 39.

  In each embodiment according to the present invention, all-cylinder operation and reduced-cylinder operation are selectively performed according to the engine operation state. That is, for example, when the engine operating state determined by the engine load L (= Ga / NE) and the engine speed NE is within the all-cylinder operation region AALL shown in FIG. 2, all cylinders that operate in all cylinders 2a and 2b. Driving is performed. On the other hand, when the engine operation state is in the reduced cylinder operation region APRT, the reduced cylinder operation is performed in which the operation is stopped in some cylinders and the operation is performed in the remaining cylinders.

  In this way, when the engine load L is relatively low, the reduced cylinder operation is performed to reduce the amount of combustion consumption, and when the engine load L is increased, the entire cylinder operation is performed so that torque shortage does not occur. The map of FIG. 2 is stored in the ROM 32 in advance.

  There are various ways to perform reduced-cylinder operation. In each embodiment according to the present invention, when the reduced cylinder operation is to be performed, the operation is stopped in the cylinder 2b of the bank 1b and the operation is performed in the cylinder 2a of the bank 1a. However, it is also possible to sequentially change the cylinders whose operation is stopped when the reduced cylinder operation is performed.

  When the reduced-cylinder operation is performed, the ignition timing θa of the cylinder 2a of the bank 1a that is operated at this time is set to the reduced-cylinder operation ignition timing θPRT (θa = θPRT). This reduced-cylinder operation ignition timing θPRT is obtained in advance as a function of the engine operation state, for example, the engine load L and the engine speed NE, and is stored in advance in the ROM 32 in the form of a map shown in FIG. Yes.

  On the other hand, when the all-cylinder operation is performed, the ignition timing θa of the cylinder 2a of the bank 1a and the ignition timing θb of the cylinder 2b of the bank 1b are both set to the all-cylinder operation ignition timing θALL (θa, θb = θALL). ). This all-cylinder operation ignition timing θALL is obtained in advance as a function of the engine operation state, for example, the engine load L and the engine speed NE, and is stored in advance in the ROM 32 in the form of a map shown in FIG. Yes.

  However, the ignition timings θa and θb are set to be different from each other for a while after the reduced-cylinder operation is switched to the all-cylinder operation. An ignition timing setting method according to an embodiment of the present invention in this case will be described with reference to FIGS.

  During the reduced-cylinder operation, as described above, the operation is performed in the cylinder 2a of the bank 1a, and the operation of the cylinder 2b of the bank 1b is stopped. Next, when the engine acceleration operation is performed and the engine operation state shifts from the P point to the Q point shown in FIG. 4, for example, the reduced cylinder operation is switched to the all cylinder operation, and the operation of the cylinder 2a of the bank 1a is continued. The operation of the cylinder 2b of the bank 1b is resumed.

  FIG. 5 shows a case where the engine slow acceleration operation is performed and the reduced cylinder operation is switched to the all cylinder operation. The all-cylinder operation flag XALL shown in FIG. 5 is set when all-cylinder operation is to be performed (XALL = 1), and is reset when the reduced-cylinder operation is to be performed (XALL = 0).

  Referring to FIG. 5, when the all-cylinder operation flag XALL is set as indicated by the arrow X (XALL = 1), the ignition timing θa of the cylinder 2a is reduced to the ignition timing θPRT for the reduced cylinder operation as indicated by the dotted line. To the ignition timing θALL for all cylinder operation. Next, after a slight delay time for torque shock reduction, the operation of the cylinder 2b is resumed. At this time, the ignition timing θb of the cylinder 2b is set to the slow acceleration switching ignition timing θSWTm as shown by the solid line. .

  This slow acceleration switching ignition timing θSWTm is set to be retarded from the all-cylinder operation ignition timing θALL in order to reduce the torque shock accompanying the resumption of operation of the cylinder 2b. Although the slow acceleration switching ignition timing θSWTm may be kept constant, for example, in the embodiment according to the present invention, the slow acceleration switching ignition timing θSWTm is advanced with the passage of time. Specifically, for example, θSWTmi is set as an initial value, and is advanced by, for example, a constant update value Δθm toward the all-cylinder operation ignition timing θALL (θSWTm = θSWTm−Δθm). As a result, torque is gradually increased while torque shock is suppressed.

  Next, as indicated by an arrow Y in FIG. 5, when the ignition timing θb of the cylinder 2b substantially coincides with the all-cylinder operation ignition timing θALL, thereafter, the ignition timing θa of the cylinder 2a and the ignition timing θb of the cylinder 2b are both. The all-cylinder operation ignition timing θALL is set.

  On the other hand, FIG. 6 shows a case where the engine rapid acceleration operation is performed and the reduced cylinder operation is switched to the all cylinder operation. The all-cylinder operation flag XALL shown in FIG. 5 is set when all-cylinder operation is to be performed (XALL = 1), and is reset when the reduced-cylinder operation is to be performed (XALL = 0).

  Referring to FIG. 6, when the all-cylinder operation flag XALL is set as indicated by the arrow X (XALL = 1), the ignition timing θa of the cylinder 2a is reduced to the ignition timing θPRT for the reduced cylinder operation as indicated by the dotted line. To the ignition timing θALL for all cylinder operation. Next, after a slight delay time has elapsed, the operation of the cylinder 2b is resumed. At this time, the ignition timing θb of the cylinder 2b is set to the ignition timing θSWTr for rapid acceleration switching as shown by the solid line.

  This sudden acceleration switching ignition timing θSWTr is set to be more advanced than the all-cylinder operation ignition timing θALL in order to generate torque corresponding to sudden acceleration. In the embodiment according to the present invention, the ignition timing θSWTr for sudden acceleration switching is obtained in advance as a function of the engine operating state, for example, the engine load L and the engine speed NE, like the ignition timing θALL for all cylinder operation. 7 is stored in advance in the ROM 32 in the form of a map shown in FIG. This slow acceleration switching ignition timing θSWTm is set to an advance side with respect to the all cylinder operating ignition timing θALL in the same engine operating state.

  That is, since the cylinder wall temperature of the cylinder 2b in which the operation has been resumed is lower than the cylinder wall temperature of the cylinder 2a in which the operation has been continued, the ignition timing θb of the cylinder 2b when the operation is resumed is advanced, particularly in the vicinity of the MBT. Even if set, knocking does not occur, and a large torque can be obtained. As a result, as shown in FIG. 6, the torque is greatly increased during the engine rapid acceleration operation.

  Next, for example, when a predetermined set time t1 has elapsed since switching to the all-cylinder operation as indicated by an arrow Z in FIG. 6, the ignition timing θb of the cylinder 2b is switched to the ignition timing θALL for all-cylinder operation. .

  Therefore, in general terms, when the reduced-cylinder operation is switched to the all-cylinder operation, the ignition timing θb of the cylinder 2b at which the operation is restarted at this time is changed to the ignition timing θa of the cylinder 2a that is continuously operated. This means that the advance side is temporarily set.

  However, the cylinder inner wall temperature of the cylinder 2b when the reduced cylinder operation is switched to the all cylinder operation may vary depending on the time of the reduced cylinder operation performed immediately before, that is, the time during which the operation is stopped. If the ignition timing θb is set to the advance side when the cylinder inner wall temperature of the cylinder 2b is high, knocking may occur.

  Therefore, in the embodiment according to the present invention, the cylinder inner wall temperature TWb of the cylinder 2b is predicted when the reduced cylinder operation is switched to the all cylinder operation, and the cylinder inner wall temperature TWb of the cylinder 2b is lower than the predetermined set temperature T1. Sometimes the ignition timing θb of the cylinder 2b is set to the slow acceleration switching ignition timing θSWTm, and when the cylinder inner wall temperature TWb of the cylinder 2b is higher than the set temperature T1, the ignition timing θb of the cylinder 2b is set to the ignition timing θALL for all cylinder operation. It is set to. In other words, when the cylinder inner wall temperature TWb of the cylinder 2b is lower than the set temperature T1, the ignition timing θb of the cylinder 2b is set to an advance side with respect to the ignition timing θa of the cylinder 2a, and the cylinder inner wall temperature TWb of the cylinder 2b is set to the set temperature. When it is higher than T1, the ignition timing θb of the cylinder 2b coincides with the ignition timing θa of the cylinder 2a.

  There are various methods for predicting the cylinder inner wall temperature TWb of the cylinder 2b. In the embodiment according to the present invention, for example, the time of the reduced cylinder operation performed immediately before, that is, the time when the operation of the cylinder 2b is stopped, the time after the operation of the cylinder 2b is restarted, the engine load L and the engine rotation. The cylinder inner wall temperature TWb is predicted based on the engine operating state such as a number NE and the coolant temperature THWa of the bank a.

  FIG. 8 shows an operation control routine of the embodiment according to the present invention. This routine is executed by interruption every predetermined time.

  Referring to FIG. 8, first, at step 100, it is judged using the map of FIG. 2 whether or not the current engine operating state is in the all cylinder operating region AALL. When the current engine operation state is within the all-cylinder operation region AALL, the routine proceeds to step 101 where the all-cylinder operation flag XALL is set (XALL = 1). In subsequent step 102, all-cylinder operation is performed. On the other hand, when the current engine operation state is in the reduced-cylinder operation region APRT, the routine proceeds to step 103 where the all-cylinder operation flag XALL is reset (XALL = 0). In the subsequent step 104, reduced cylinder operation is performed.

  FIG. 9 shows an ignition timing control routine of the embodiment according to the present invention. This routine is executed by interruption every predetermined crank angle.

  Referring to FIG. 9, first, at step 110, it is judged if the all cylinder operation flag XALL is set. When the all-cylinder operation flag XALL is reset (XALL = 0), that is, when the reduced-cylinder operation is to be performed, the routine proceeds to step 111, and the reduced-cylinder operation ignition timing θPRT is calculated from the map of FIG. The In the subsequent step 112, the ignition timing θa of the cylinder 2a is set to the ignition timing θPRT for reduced cylinder operation. Next, the routine proceeds to step 113, where the all cylinder operation flag XALL in the current processing cycle is stored as XALLp.

  In contrast, when the all-cylinder operation flag XALL is set in step 110 (XALL = 1), that is, when all-cylinder operation is to be performed, the routine proceeds to step 114 where the all-cylinder operation ignition timing θALL is shown in FIG. B) is calculated from the map. In the following step 115, the ignition timing θa of the cylinder 2a is set to the ignition timing θALL for all cylinder operation (θa = θALL). In the following step 116, a routine for calculating the ignition timing θb of the cylinder 2b is executed. This routine is illustrated in FIG.

  Referring to FIG. 10, first, in step 120, it is determined whether or not the all cylinder operation flag XALL in the current process cycle is set and the all cylinder operation flag XALLp in the previous process cycle is reset. When XALL = 1 and XALLp = 0, that is, when the process proceeds to step 120 for the first time after switching from the reduced cylinder operation to the all cylinder operation, the process then proceeds to step 121, where a counter C representing the time since the start of all cylinder operation is started. Is set to 1 (C = 1). In the following step 122, it is determined whether or not the change rate dDEP of the depression amount DEP of the accelerator pedal 42 is larger than a predetermined set value d1. When dDEP ≦ d1, that is, when the engine is accelerating slowly, the routine proceeds to step 123 where the slow acceleration switching ignition timing θSWTm is progressively advanced from the initial value θSWTmi toward the all cylinder operation ignition timing θALL. Is done. In the following step 124, the ignition timing θb of the cylinder 2b is set to the slow acceleration switching ignition timing θSWTm. Next, the routine proceeds to step 113.

  On the other hand, when dDEP> d1, that is, when the engine rapid acceleration operation is being performed, the routine proceeds from step 122 to step 125, where the cylinder inner wall temperature TWb of the cylinder 2b is calculated. In the following step 126, it is determined whether or not the cylinder inner wall temperature TWb of the cylinder 2b is lower than the set temperature T1. When TWb <T1, the routine proceeds to step 127, where the ignition timing θSWTr for sudden acceleration switching is calculated from the map of FIG. In the following step 128, the ignition timing θb of the cylinder 2b is set to the rapid acceleration switching ignition timing θSWTr. Next, the routine proceeds to step 113. On the other hand, when TWb ≧ T1 in step 126, the routine proceeds to step 129, where the ignition timing θb of the cylinder 2b is set to the ignition timing θALL for all cylinder operation. Next, the routine proceeds to step 113.

  On the other hand, in step 120, when XALL = 1 and XALLp = 0 are not satisfied, that is, when all cylinders are continuously operated, the routine proceeds to step 130 where the counter C is incremented by 1 (C = C + 1). In the following step 131, it is determined whether or not the counter C is larger than C1 representing the set time t1 (FIG. 6) described above. When C ≦ C1, that is, when the set time t1 has not yet elapsed since switching to the all-cylinder operation, the routine proceeds to step 122 where the ignition timing θb of the cylinder 2b is the slow acceleration switching ignition timing θSWTm, the rapid acceleration switching. The hour ignition timing θSWTr or the all-cylinder operation timing ignition timing θALL is set, and then the routine proceeds to step 113. On the other hand, when C> C1, that is, when the set time t1 has elapsed since switching to the all cylinder operation, the routine proceeds from step 131 to step 129, where the ignition timing θb of the cylinder 2b becomes the ignition timing θALL for all cylinder operation. Then, the process proceeds to step 113.

  Next, another embodiment of the ignition timing control during engine rapid acceleration operation will be described with reference to FIGS. 11 and 12.

  As described above, knocking does not occur even if the ignition timing θb of the cylinder 2b that is restarted when the reduced-cylinder operation is switched to the all-cylinder operation is advanced, because the cylinder wall temperature TWb of the cylinder 2b This is because the lower the cylinder inner wall temperature TWb, the larger the advance amount of the ignition timing θb.

  However, the cylinder wall temperature TWb gradually increases with the elapse of time after the operation of the cylinder 2b is resumed, and therefore the advance amount of the ignition timing θb needs to be reduced with the elapse of time.

  Therefore, in the embodiment shown in FIG. 11, the ignition timing θSWTr for sudden acceleration switching is first set to an advance side with respect to the ignition timing θALL for all cylinder operation, and then retarded with the passage of time. Specifically, for example, θSWTri, which is more advanced than the ignition timing θALL for all cylinder operation, is set as an initial value, and is retarded, for example, by a constant update value Δθr toward the ignition timing θALL for all cylinder operation (θSWTr = ΘSWTr + Δθr).

  In this way, knocking can be reliably prevented while securing a large torque in the early stage of acceleration. Next, in the example shown in FIG. 11, as indicated by the arrow Z, when the ignition timing θb of the cylinder 2b substantially coincides with the ignition timing θALL for all cylinder operation, thereafter, the ignition timing θa of the cylinder 2a and the ignition of the cylinder 2b Both the timings θb are set to the all-cylinder operation ignition timing θALL.

  FIG. 12 shows a routine for calculating the ignition timing θb of the cylinder 2b in the embodiment shown in FIG. This routine is executed in step 116 of FIG.

  Referring to FIG. 12, first, at step 140, it is judged if XALL = 1 and XALLp = 0. If XALL = 1 and XALLp = 0, then the routine proceeds to step 141 where it is judged if the engine is in rapid acceleration operation (dDEP> d1). When the engine is accelerating slowly (dDEP ≦ d1), the routine proceeds to step 142, where the slow acceleration switching ignition timing θSWTm is gradually advanced from the initial value θSWTmi toward the all cylinder operation ignition timing θALL. Is done. In the following step 143, the ignition timing θb of the cylinder 2b is set to the slow acceleration switching ignition timing θSWTm. Next, the process proceeds to step 113 in FIG.

  On the other hand, when the engine rapid acceleration operation is being performed (dDEP> d1), the process proceeds from step 141 to step 144, and the cylinder inner wall temperature TWb of the cylinder 2b is calculated. In the following step 145, it is determined whether or not the cylinder inner wall temperature TWb of the cylinder 2b is lower than the set temperature T1. When TWb <T1, the routine proceeds to step 146, where the rapid acceleration switching ignition timing θSWTr is sequentially retarded from the initial value θSWTri toward the all-cylinder operation ignition timing θALL. In the subsequent step 147, the ignition timing θb of the cylinder 2b is set to the ignition timing θSWTr for sudden acceleration switching. Next, the process proceeds to step 113 in FIG. On the other hand, when TWb ≧ T1 at step 145, the routine proceeds to step 148, where the ignition timing θb of the cylinder 2b is set to the ignition timing θALL for all cylinder operation. Next, the process proceeds to step 113 in FIG.

  On the other hand, when XALL = 1 and XALLp = 0 are not satisfied at step 140, the routine proceeds to step 149, where whether the ignition timing θb of the cylinder 2b is equal to the ignition timing θALL for all cylinder operation or is set to the retard side. Is determined. When θb <θALL, the routine proceeds to step 141 where the ignition timing θb of the cylinder 2b is set to the slow acceleration switching ignition timing θSWTm, the rapid acceleration switching ignition timing θSWTr, or the all cylinder operation ignition timing θALL, and then Proceed to step 113 in FIG. On the other hand, when θb ≧ θALL, the routine proceeds from step 149 to step 148, where the ignition timing θb of the cylinder 2b is set to the ignition timing θALL for all cylinder operation, and then the routine proceeds to step 113 in FIG.

  Other configurations and operations of the embodiment according to the present invention described with reference to FIGS. 11 and 12 are the same as those of the embodiment described with reference to FIGS.

  Still another embodiment of the ignition timing control during the engine rapid acceleration operation will be described with reference to FIGS. 13 to 15.

  As described above, the ignition timing θb of the cylinder 2b that is restarted when the reduced-cylinder operation is switched to the all-cylinder operation is set to an advance side with respect to the ignition timing θa of the cylinder 2a that is continuously operated. The In this case, the extent to which the ignition timing θb can be advanced with respect to the ignition timing θa ultimately depends on the difference ΔTW between the cylinder inner wall temperature TWa of the cylinder 2a and the cylinder inner wall temperature TWb of the cylinder 2b.

  Therefore, in the embodiment shown in FIG. 13, the temperature difference ΔTW between the cylinder inner wall temperature TWa and the cylinder inner wall temperature TWb is predicted, the advance angle correction amount Δadv is calculated based on this temperature difference ΔTW, and the ignition timing θa, that is, all cylinders are calculated. The ignition timing θALL for the rapid acceleration switching is set to the ignition timing θSWTr for the rapid acceleration switching (θSWTr = θALL−Δθadv), and the ignition timing θb for the rapid acceleration switching is set. θSWTr is set. In this way, knocking can be reliably prevented.

  As shown in FIG. 14, the advance correction amount Δθadv is obtained in advance so as to decrease as the temperature difference ΔTW decreases, and is stored in the ROM 32 in advance in the form of a map shown in FIG. On the other hand, for example, the time of the reduced cylinder operation performed immediately before, that is, the time when the operation of the cylinder 2b is stopped, the time after the operation of the cylinder 2a is restarted, the engine load L and the engine speed NE, etc. A temperature difference ΔTW is predicted based on the engine operating state and the coolant temperatures THWa and THWb of the banks 1a and 1b.

  Next, in the example shown in FIG. 13, as indicated by the arrow Z, when the ignition timing θb of the cylinder 2b substantially coincides with the ignition timing θALL for all cylinder operation, thereafter, the ignition timing θa of the cylinder 2a and the ignition of the cylinder 2b Both the timings θb are set to the all-cylinder operation ignition timing θALL.

  FIG. 15 shows a routine for calculating the ignition timing θb of the cylinder 2b in the embodiment shown in FIG. This routine is executed in step 116 of FIG.

  Referring to FIG. 15, first, at step 160, it is judged if XALL = 1 and XALLp = 0. If XALL = 1 and XALLp = 0, then the routine proceeds to step 161, where it is judged if the engine is in rapid acceleration operation (dDEP> d1). When the engine slow acceleration operation is being performed (dDEP ≦ d1), the routine proceeds to step 162 where the slow acceleration switching ignition timing θSWTm is gradually advanced from the initial value θSWTmi toward the all cylinder operation ignition timing θALL. Is done. In the following step 163, the ignition timing θb of the cylinder 2b is set to the slow acceleration switching ignition timing θSWTm. Next, the process proceeds to step 113 in FIG.

  On the other hand, when the engine rapid acceleration operation is being performed (dDEP> d1), the process proceeds from step 161 to step 164, and a temperature difference ΔTW between the cylinder inner wall temperature TWa and the cylinder inner wall temperature TWb is calculated. In the following step 165, the advance angle correction amount Δadv is calculated from the map of FIG. In subsequent step 166, ignition timing θSWTr for sudden acceleration switching is calculated (θSWTr = θALL−Δθadv). In the following step 167, the ignition timing θb of the cylinder 2b is set to the rapid acceleration switching ignition timing θSWTr. Next, the process proceeds to step 113 in FIG.

  On the other hand, when XALL = 1 and XALLp = 0 are not satisfied at step 160, the routine proceeds to step 169 where it is determined whether the ignition timing θb of the cylinder 2b is equal to the ignition timing θALL for all cylinder operation or set to the retard side. Is determined. When θb <θALL, the routine proceeds to step 161 where the ignition timing θb of the cylinder 2b is set to the slow acceleration switching ignition timing θSWTm, the rapid acceleration switching ignition timing θSWTr, or the all cylinder operation ignition timing θALL, and then Proceed to step 113 in FIG. On the other hand, when θb ≧ θALL, the routine proceeds from step 169 to step 168, where the ignition timing θb of the cylinder 2b is set to the ignition timing θALL for all cylinder operation, and then the routine proceeds to step 113 in FIG.

  Other configurations and operations of the embodiment according to the present invention described with reference to FIGS. 13 to 15 are the same as those of the embodiment described with reference to FIGS.

  With reference to FIGS. 16 to 18, another embodiment of the ignition timing control during engine slow acceleration operation according to the present invention will be described.

  When the reduced cylinder operation is performed, the operation of the cylinder 2a of the bank 1a is stopped in the internal combustion engine shown in FIG. At this time, high temperature exhaust gas does not flow into the catalytic converter 10a connected to the bank 1a, or low temperature air that has passed through the cylinder 1a flows. As a result, the temperature of the catalytic converter 10a decreases as the elapsed time of the reduced cylinder operation becomes longer.

  On the other hand, the temperature of the exhaust gas can be raised by retarding the ignition timing of the cylinder. Therefore, in the embodiment shown in FIG. 16, when switching from reduced-cylinder operation to all-cylinder operation, the slow acceleration switching ignition timing θSWTm is temporarily set to the ignition timing θa of the cylinder 2a, that is, the all-cylinder operation ignition timing θALL. The ignition timing θa of the cylinder 2a is set to the slow acceleration switching ignition timing θSWTm. If it does in this way, the temperature of catalytic converter 10a can be raised rapidly.

  In this case, the slow acceleration switching ignition timing θSWTm is obtained in advance as a function of the engine operating state, for example, the engine load L and the engine speed NE, and is stored in advance in the ROM 32 in the form of a map shown in FIG. Yes. Alternatively, the slow acceleration switching ignition timing θSWTm can be set according to the temperature of the catalytic converter 10a.

  Next, as shown by an arrow Y in the example shown in FIG. 16, when a predetermined set time t2 elapses after switching to the all-cylinder operation, the ignition timing θb of the cylinder 2b becomes the ignition for all-cylinder operation. It is switched to time θALL.

  FIG. 18 shows a routine for calculating the ignition timing θb of the cylinder 2b in the embodiment shown in FIG. This routine is executed in step 116 of FIG.

  Referring to FIG. 18, first, at step 180, it is judged if XALL = 1 and XALLp = 0. When XALL = 1 and XALLp = 0, the routine proceeds to step 181 where the counter C representing the time since the start of all cylinder operation is set to 1 (C = 1). In the following step 182, it is determined whether or not the engine is in rapid acceleration operation (dDEP> d1). When the engine slow acceleration operation is being performed (dDEP ≦ d1), the routine proceeds to step 182a, where it is determined whether or not the counter C is equal to or less than C2 representing the set time t2 (FIG. 16). When C ≦ C2, that is, when the set time t2 has not yet elapsed since switching to the all-cylinder operation, the routine proceeds to step 183, where the ignition timing θSWTm for slow acceleration switching is calculated from the map of FIG. In the following step 184, the ignition timing θb of the cylinder 2b is set to the slow acceleration switching ignition timing θSWTm. Next, the process proceeds to step 113 in FIG. On the other hand, when C> C2, when the set time t2 has elapsed since switching to the all-cylinder operation, the routine jumps to step 189, where the ignition timing θb of the cylinder 2b is set to the all-cylinder operation ignition timing θALL. . Next, the process proceeds to step 113 in FIG.

  On the other hand, when the engine rapid acceleration operation is being performed (dDEP> d1), the process proceeds from step 182 to step 185, and the cylinder inner wall temperature TWb of the cylinder 2b is calculated. In the following step 186, it is determined whether or not the cylinder inner wall temperature TWb of the cylinder 2b is lower than the set temperature T1. When TWb <T1, the routine proceeds to step 187, where the ignition timing θSWTr for sudden acceleration switching is calculated from the map of FIG. At the subsequent step 188, the ignition timing θb of the cylinder 2b is set to the ignition timing θSWTr for sudden acceleration switching. Next, the process proceeds to step 113 in FIG. On the other hand, when TWb ≧ T1 in step 186, the routine proceeds to step 189, where the ignition timing θb of the cylinder 2b is set to the ignition timing θALL for all cylinder operation. Next, the process proceeds to step 113 in FIG.

  On the other hand, in step 180, when XALL = 1 and XALLp = 0 are not satisfied, the routine proceeds to step 190 where the counter C is incremented by 1 (C = C + 1). In the following step 191, it is determined whether or not the counter C is larger than C1 representing the set time t1 (FIG. 6) described above. When C ≦ C1, the routine proceeds to step 182 where the ignition timing θb of the cylinder 2b is set to the slow acceleration switching ignition timing θSWTm, the rapid acceleration switching ignition timing θSWTr, or the all cylinder operation ignition timing θALL, and then Proceed to step 113 in FIG. On the other hand, when C> C1, the routine proceeds from step 191 to step 189, where the ignition timing θb of the cylinder 2b is set to the ignition timing θALL for all cylinder operation, and then the routine proceeds to step 113 in FIG.

  Other configurations and operations of the embodiment according to the present invention described with reference to FIGS. 16 to 18 are the same as those of the embodiment described with reference to FIGS.

  In each of the embodiments described so far, the ignition timings θPRT (FIG. 3A), θALL (FIG. 3B), θSWTr (FIG. 7), and θSWTm (FIG. 17) represent the engine load L and the engine speed. Calculated based on NE. However, in an internal combustion engine that can adjust the valve overlap amount during which the intake valve and the exhaust valve of each cylinder 2a, 2b are simultaneously open, the engine load L, the engine speed NE, and the valve overlap amount These ignition timings may be obtained based on the above.

1 is an overall view of an internal combustion engine. It is a map which shows the all-cylinder operation area | region AALL and the reduced cylinder operation area | region APRT. FIG. 6 is a map showing a reduced-cylinder operation ignition timing θPRT and an all-cylinder operation ignition timing θALL. It is a figure for demonstrating the Example by this invention. It is a time chart for demonstrating the Example by this invention. It is a time chart for demonstrating the Example by this invention. 7 is a map showing ignition timing θSWTr for sudden acceleration switching. It is a flowchart which shows an operation control routine. It is a flowchart which shows the ignition timing control routine of the Example by this invention. It is a flowchart which shows the ignition timing control routine of the Example by this invention. It is a time chart for demonstrating another Example by this invention. It is a flowchart which shows the ignition timing control routine of another Example by this invention. It is a time chart for demonstrating another Example by this invention. It is a map which shows advance angle correction amount (theta) adv. It is a flowchart which shows the ignition timing control routine of another Example by this invention. It is a time chart for demonstrating another Example by this invention. 4 is a map showing an ignition timing θSWTm for slow acceleration switching. It is a flowchart which shows the ignition timing control routine of another Example by this invention.

Explanation of symbols

1 Engine body 2a, 2b Cylinder 14 Spark plug 43 Depression amount sensor

Claims (1)

In a spark ignition internal combustion engine that can switch between reduced cylinder operation in which operation is stopped in some cylinders and operation in the remaining cylinders and all cylinder operation in which all cylinders are operated. When the operation is switched to the all-cylinder operation, the ignition timings of the some cylinders that are restarted at this time are temporarily advanced from the ignition timings of the remaining cylinders that are continuously operated. An ignition timing control device set on the corner side, and when the engine slow acceleration operation is performed and the reduced-cylinder operation is switched to the all-cylinder operation, the ignition timings of the some cylinders that are restarted at this time are set. When the engine is set to the retard side temporarily from the ignition timing of the remaining cylinders that are continuously operated and the engine sudden acceleration operation is performed and the reduced cylinder operation is switched to the all cylinder operation, Ignition of some of the cylinders that are restarted at this time Period and ignition timing operation has been temporarily set to the advance side than the ignition timing of the remaining cylinders being performed continuously controller.

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