JP2013160182A - Internal combustion engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine control device capable of improving efficiency of scavenging redidual gas in a cylinder when secondary air is supplied to an exhaust system, and thereby capable of suppressing occurrence of knocking and also capable of improving combustion efficiency, generated output power, and fuel consumptions.SOLUTION: A control device 1 for an internal combustion engine 3 includes a secondary air supply device 30 and an ECU2. The secondary air supply device 30 jets the secondary air to a first exhaust port 9d toward the interior of a cylinder 3a in the direction away from a second exhaust port 9e. In order to scavenge the residual gas in the cylinder 3a, the ECU2 controls the secondary air supply device 30 so as to supply the secondary air to the first exhaust port 9d at the end of an opening-valve period of two exhaust valves 5, 5 (step 10 to 21).

Description

  The present invention relates to a control device for an internal combustion engine that controls a secondary air supply device that supplies secondary air to an exhaust system of the internal combustion engine.

  Conventionally, what was described in patent document 1 is known as a control apparatus of an internal combustion engine. This internal combustion engine is of a four-cylinder type and includes a secondary air supply device that supplies secondary air into an exhaust passage thereof, and an exhaust gas purification catalyst for purifying exhaust gas. The secondary air supply device includes four nozzles. During operation of the secondary air supply device, secondary air is supplied into the four exhaust branch passages of the exhaust passage by the four nozzles, respectively. .

  In this control device, when the internal combustion engine is cold started, the air-fuel ratio of the air-fuel mixture is controlled to be richer than the stoichiometric air-fuel ratio in order to promote warm-up of the internal combustion engine. At the same time, secondary air supply control is performed for each cylinder in order to promote activation of the exhaust gas purification catalyst and exhaust gas purification. That is, by driving the secondary air supply device, the secondary air is injected from the nozzle into the exhaust branch passage of the exhaust passage at a timing that does not flow back into the cylinder. Thereby, the activation of the exhaust gas purification catalyst and the exhaust gas purification are promoted by controlling the air-fuel ratio of the exhaust gas to the lean side.

Japanese Patent No. 4411927

  In general, in an internal combustion engine, combustion gas and unburned gas (hereinafter referred to as “in-cylinder gas”) generated in the cylinder by combustion of the air-fuel mixture are discharged outside the cylinder through an exhaust valve and an exhaust port in the exhaust stroke. However, it does not exhaust sufficiently and tends to remain in the cylinder as residual gas. Therefore, as a method of scavenging the residual gas in the cylinder, a valve overlap period is set in which the intake valve and the exhaust valve are simultaneously opened, the intake port pressure is set higher than the exhaust port pressure, and the air is A method of introducing the cylinder into the cylinder during the overlap period is known.

  However, with such a scavenging technique, it is difficult to efficiently scavenge the residual gas from the cylinder, and as a result, a certain amount of residual gas is generated in the cylinder. In particular, when the exhaust pressure is higher than the intake pressure, for example, when the internal combustion engine is equipped with a turbocharger and is in a transient operating condition state during acceleration, the scavenging method cannot scavenge residual gas. When residual gas is generated in the cylinder as described above, knocking is likely to occur due to an increase in the in-cylinder temperature. Further, when knocking is to be avoided, the combustion efficiency is lowered, and the generated output and fuel consumption of the internal combustion engine are reduced. In the case of the control device disclosed in Patent Document 1, activation of the exhaust gas purification catalyst and exhaust gas purification can be promoted by the above-described secondary air supply control, but residual gas in the cylinder can be scavenged. Therefore, the above-described problem occurs due to the generation of residual gas in the cylinder.

  The present invention has been made to solve the above-described problems, and in the case of supplying secondary air to the exhaust system, it is possible to improve the scavenging efficiency of residual gas in the cylinder, thereby preventing occurrence of knocking. It is an object of the present invention to provide a control device for an internal combustion engine that can suppress the combustion efficiency, the generated output, and the fuel consumption.

  In order to achieve the above-mentioned object, the invention according to claim 1 is a cylinder having two exhaust valves 5 and 5 and an intake valve 4 for opening and closing two exhaust ports (first and second exhaust ports 9d and 9e), respectively. A control device 1 for an internal combustion engine 3 provided for each 3a, and toward one of the two exhaust ports (first exhaust port 9d) where one of the two exhaust valves 5 and 5 opens and closes toward the inside of the cylinder 3a, A secondary air supply device 30 that supplies secondary air in a direction away from the other of the two exhaust ports (second exhaust port 9e), and two exhaust valves 5, 5 for scavenging residual gas in the cylinder 3a. Secondary air control means (ECU2, steps 10 to 21) for controlling the secondary air supply device 30 so as to supply secondary air to one exhaust port (first exhaust port 9d) at the end of the valve opening period And characterized by comprising .

  According to this control device for an internal combustion engine, in order to scavenge residual gas in the cylinder, the secondary air is supplied to one of the two exhaust ports at the end of the opening period of the two exhaust valves. The air supply device is controlled. As a result, the secondary air is supplied to one of the two exhaust ports, in which one of the two exhaust valves is opened and closed, in the direction away from the other exhaust port by the secondary air supply device. Therefore, the secondary air flows into the cylinder from one exhaust port opened by one exhaust valve. At that time, since the piston is located near the top dead center at the end of the exhaust valve opening period, the secondary air flows to the intake valve side along the top surface of the piston and the inner wall of the cylinder. It flows to the other exhaust valve side. And it flows out to the exhaust passage side through the other exhaust port opened by the other exhaust valve.

  As described above, the secondary air flowing into the cylinder circulates in the vicinity of one exhaust valve, the vicinity of the intake valve, and the vicinity of the other exhaust valve, and then enters the exhaust passage from the other exhaust port. Since it flows out, the residual gas in the cylinder can be efficiently scavenged by the secondary air, and the scavenging efficiency of the residual gas can be improved. Thereby, scavenging efficiency of the residual gas can be improved, so that occurrence of knocking can be suppressed. Further, the combustion efficiency can be improved, and the generated output and fuel consumption of the internal combustion engine can be improved. In addition to this, the secondary air flows to the exhaust passage side together with the residual gas, and the air-fuel ratio of the exhaust gas becomes the lean side, so that the air-fuel ratio of the air-fuel mixture in the cylinder can be controlled to the richer side accordingly, Thus, the occurrence of knocking can be further suppressed. As a result, since the compression ratio of the air-fuel mixture can be set higher, the combustion efficiency can be further improved, and the generated output and fuel consumption of the internal combustion engine can be further improved.

  According to a second aspect of the present invention, in the control device 1 for the internal combustion engine 3 according to the first aspect, the opening of one exhaust port (first exhaust port 9d) and the other exhaust port (first exhaust port) of the top wall of the cylinder 3a. 2 is provided with a guide portion (guide wall 3e) for guiding the secondary air to the intake valve 4 side.

  According to this control device for an internal combustion engine, a guide portion for guiding secondary air to the intake valve side is provided at a portion of the top wall of the cylinder between the opening of one exhaust port and the opening of the other exhaust port. Since it is provided, the secondary air flowing into the cylinder from the opening of one exhaust port can be reliably guided to the intake valve side while preventing the secondary air from flowing to the opening side of the other exhaust port, The scavenging efficiency of the residual gas can be further improved. As a result, the occurrence of knocking can be further improved, and the combustion efficiency, generated output, and fuel consumption can be further improved.

It is a figure which shows typically a part of structure of the control apparatus which concerns on one Embodiment of this invention, and the structure of the internal combustion engine to which this is applied. It is a figure which shows typically schematic structure of an internal combustion engine. FIG. 5 is a perspective view of the arrangement of intake ports, exhaust ports, and air control valves in each cylinder when viewed in plan. It is the figure which looked at the opening vicinity of two exhaust ports of each cylinder from the piston side. It is a perspective view for demonstrating the scavenging operation | movement of the residual gas by a secondary air supply apparatus. It is a figure which shows the valve lift curve of an intake valve and an exhaust valve, and the valve opening period of an air control valve. It is a flowchart which shows a secondary supercharging control process. It is a flowchart which shows a secondary air control process.

  Hereinafter, an internal combustion engine control apparatus according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the control device 1 of the present invention includes an ECU 2, and various control processes in an internal combustion engine (hereinafter referred to as “engine”) 3 are executed by the ECU 2 as will be described later.

  As shown in FIGS. 1 and 2, the engine 3 is an in-line four-cylinder gasoline engine having four sets of cylinders 3a and pistons 3b (only one is shown), and is mounted on a vehicle (not shown). In the following description, the four cylinders 3a are appropriately referred to as “first to fourth cylinders 3a” in order from the upper side to the lower side in FIG. The engine 3 includes two intake valves 4 and 4 (only one is shown) provided for each cylinder 3a, and two exhaust valves 5 and 5 (only one is shown) provided for each cylinder 3a. Yes.

  The intake valve 4 and the exhaust valve 5 are driven by a valve operating mechanism (not shown) as the crankshaft 3d rotates, and thereby open and close with a valve lift curve shown in FIG. As shown in the figure, the engine 3 has a valve overlap period in which the intake valves 4, 4 and the exhaust valves 5, 5 are simultaneously open. This valve overlap period is the intake stroke. A predetermined crank angle position before and after the TDC position at the start is set as a start point and an end point.

  Further, as shown in the figure, during the valve overlap period, when the crank angle CA is a predetermined value CA1 (a constant value), the lift of the intake valve 4 and the lift of the exhaust valve 5 are configured to be the same value. Has been. In this case, in the secondary air control process described later, in order to prevent the residual gas in the cylinder 3a from being blown back to the intake passage 8 side by the secondary air, the valve closing timing of the air control valve 35 described later is It is set when the crank angle CA is at the predetermined value CA1. Therefore, in the following description, the predetermined value CA1 is referred to as “predetermined valve closing angle CA1”.

  The engine 3 is provided with a spark plug 6, a fuel injection valve 7, and a crank angle sensor 20. The spark plug 6 is provided for each cylinder 3a (only one is shown), and is attached to the cylinder head 3c so as to face the combustion chamber at the center of the top wall of the cylinder 3a. The spark plug 6 is electrically connected to the ECU 2, and the discharge timing of the spark plug 6 is controlled by the ECU 2 in accordance with various operating state parameters such as an engine speed NE and an accelerator pedal opening AP, which will be described later. . That is, ignition timing control is executed.

  Further, a fuel injection valve 7 is also provided for each cylinder 3a (only one is shown), and is attached to the cylinder head 3c so as to inject fuel directly into the combustion chamber of each cylinder 3a. That is, the engine 3 is configured as a direct injection engine. The fuel injection valve 7 is electrically connected to the ECU 2, and the ECU 2 controls the fuel injection valve 7 according to various operating state parameters such as an engine speed NE, an intake pressure PB and an accelerator pedal opening AP, which will be described later. The fuel injection amount and injection timing are controlled. That is, fuel injection control is executed.

  On the other hand, the crank angle sensor 20 includes a magnet rotor and an MRE pickup, and outputs a CRK signal and a TDC signal, which are pulse signals, to the ECU 2 as the crankshaft 3d rotates. This CRK signal is output with one pulse for each crank angle of 1 °, and the ECU 2 calculates the engine speed (hereinafter referred to as “engine speed”) NE of the engine 3 based on the CRK signal. The TDC signal is a signal indicating that the piston 3b of each cylinder 3a is at a predetermined crank angle position slightly before the TDC position of the intake stroke, and one pulse is output for each predetermined crank angle.

  The distributor (not shown) of the engine 3 is provided with a cylinder discrimination sensor 21, which outputs a cylinder discrimination signal, which is a pulse signal for discriminating the cylinder, to the ECU 2. The ECU 2 calculates the crank angle CA in each cylinder 3a based on the cylinder discrimination signal, the CRK signal, and the TDC signal. Specifically, the crank angle CA is reset to the value 0 when the TDC signal of the cylinder 3a is generated, and is incremented every time the CRK signal is generated. As a result, the crank angle CA in each cylinder 3a is 0 ° at the TDC position at the start of the intake stroke, 180 ° at the BDC position at the start of the compression stroke, 360 ° at the TDC position at the start of the expansion stroke, and at the start of the exhaust stroke. It is calculated to be 540 ° at the BDC position, and is reset from 720 ° to 0 ° when it reaches the TDC position at the start of the intake stroke.

  On the other hand, the intake passage 8 of the engine 3 has one main passage portion 8a, an intake chamber 8b provided on the downstream side of the main passage portion 8a, and four branches extending from the intake chamber 8b to the four cylinders 3a. A passage portion 8c and first and second intake ports 8d, 8e branched from each of the four branch passage portions 8c and connected to each cylinder 3a are provided.

  In the main passage portion 8a of the intake passage 8, a turbocharger 10, an intercooler 11, a throttle valve mechanism 12, and the like are provided in order from the upstream side. The turbocharger 10 includes a compressor blade 10a provided upstream of the intercooler 11 in the intake passage 8, a turbine blade 10b provided in the middle of the exhaust passage 9 and rotating integrally with the compressor blade 10a, and a plurality of variable. A vane 10c (only two are shown) and a vane actuator 10d for driving the variable vane 10c are provided. In the turbocharger 10, when the turbine blade 10 b is rotationally driven by the exhaust gas in the exhaust passage 9, the compressor blade 10 a integrated therewith is also rotated at the same time, so that the air in the intake passage 8 is pressurized. That is, the supercharging operation is executed.

  The variable vane 10c is for changing the supercharging pressure generated by the turbocharger 10, and is rotatably attached to the wall of the portion of the housing that houses the turbine blade 10b. The variable vane 10c is mechanically coupled to a vane actuator 10d connected to the ECU 2. The ECU 2 changes the opening speed of the variable vane 10c (hereinafter referred to as “vane opening degree”) via the vane actuator 10d and changes the amount of exhaust gas blown to the turbine blade 10b. The rotational speed of the blade 10a is changed. More specifically, the ECU 2 controls the vane opening according to the various operating state parameters described above. Thereby, the supercharging pressure is controlled.

  Further, the intercooler 11 is an air-cooled type that performs a cooling operation by exchanging heat with the outside air when the traveling wind flows on the surface during traveling of the vehicle, and when the air passes through the interior, The air whose temperature has been raised by the supercharging operation in the turbocharger 10 is cooled.

  On the other hand, the throttle valve mechanism 12 includes a throttle valve 12a and a TH actuator 12b that opens and closes the throttle valve 12a. The throttle valve 12a is rotatably provided in the middle of the intake passage, and changes the flow rate of air passing through the throttle valve 12a by the change in the opening degree accompanying the rotation. The TH actuator 12b is a combination of a motor connected to the ECU 2 and a gear mechanism (both not shown), and is controlled by the ECU 2 to change the opening of the throttle valve 12a. More specifically, the ECU 2 controls the opening degree of the throttle valve 12a according to the various operating state parameters described above. Thereby, the amount of intake air is controlled.

  The intake chamber 8b is provided with an intake pressure sensor 22. The intake pressure sensor 22 detects an intake pressure PB, which is the pressure in the intake chamber 8b, and outputs a detection signal representing the detected pressure to the ECU 2. To do. The intake pressure PB is detected as an absolute pressure.

  On the other hand, the exhaust passage 9 of the engine 3 includes one main passage portion 9a, two branch passage portions 9b and 9b branched in two from the main passage portion 9a toward the upstream side, and these branch passage portions 9b, A total of four branch passage portions 9c that branch from the portion 9b to the upstream side and that extend to the upstream side are divided into two from the four branch passage portions 9c toward the upstream side, and are connected to the cylinders 3a. And second exhaust ports 9d and 9e.

  The first and second exhaust ports 9d and 9e are opposed to the first and second intake ports 8d and 8e, respectively, with a line connecting the centers of the four cylinders 3a in between when viewed in plan. Is arranged. In the present embodiment, the first exhaust port 9d corresponds to one exhaust port, and the second exhaust port 9e corresponds to the other exhaust port. Further, the aforementioned turbine blade 10 b is provided in the middle of the main passage portion 9 a of the exhaust passage 9.

  Further, an exhaust pressure sensor 23 is provided in the middle of the branch passage portion 9c of the first cylinder 3a. The exhaust pressure sensor 23 detects the exhaust pressure PEX that is the pressure in the branch passage portion 9c, and A detection signal representing it is output to the ECU 2. The exhaust pressure PEX is detected as an absolute pressure.

  On the other hand, the engine 3 is provided with a secondary air supply device 30. The secondary air supply device 30 supplies air in the intake chamber 8b as secondary air to the first exhaust port 9d in order to scavenge residual gas (combustion gas and unburned gas) in the cylinder 3a. And includes an air supply path 31, an electric supercharger 32, an intercooler 33, a secondary air chamber 34, four air control valves 35, and the like. The air supply path 31 has one end connected to the intake chamber 8 b and the other end connected to the secondary air chamber 34.

  The electric supercharger 32 pressurizes the secondary air in the air supply path 31, and is provided in the middle of the air supply path 31, and is a supercharger motor electrically connected to the ECU 2. 32a (see FIG. 1) and a compressor (not shown) driven by the supercharger motor 32a. In the electric supercharger 32, during the execution of the secondary supercharging control process described later, the supercharger motor 32a is controlled by the ECU 2, whereby the compressor is driven and the secondary air supercharging operation is executed. . As a result, the pressure of secondary air (hereinafter referred to as “secondary air pressure”) P2A injected from a nozzle 35a, which will be described later, of the air control valve 35 is controlled to a value that can reliably scavenge residual gas in the cylinder 3a. The

  Furthermore, the intercooler 33 is disposed downstream of the electric supercharger 32 in the air supply path 31. The intercooler 33 is an air-cooling type similar to the intercooler 11 described above, and cools the secondary air whose temperature has been increased by the supercharging operation of the electric supercharger 32.

  On the other hand, four air control valves 35 are connected to the secondary air chamber 34 at equal intervals. Each of these four air control valves 35 is electrically connected to the ECU 2 (only one is shown in FIG. 1), and the valve opening time and valve opening timing are controlled by the ECU 2.

  As shown in FIG. 3, each air control valve 35 includes a cylindrical nozzle 35a. The nozzle 35 is provided so that its tip end faces the first exhaust port 9d, and when the air control valve 35 is opened, the secondary air is directed from the tip portion toward the cylinder 3a. The fuel is injected into the exhaust port 9d (see FIG. 5). The axis A1 of the nozzle 35a extends outside the center of the opening of the first exhaust port 9d (that is, the axis of the exhaust valve 5) C1 in a plan view and away from the second exhaust port 9d. Yes. In FIGS. 3 to 5, the intake valve 4 and the exhaust valve 5 are omitted for easy understanding.

  Further, as shown in FIGS. 3 and 4, a guide wall 3e as a guide portion is provided on the top wall of the cylinder 3a (that is, the inner wall of the cylinder head 3c). FIG. 4 shows the top wall side of the cylinder 3a as viewed from the piston 3a side. The guide wall 3e is disposed in a portion of the top wall between the openings of the first and second exhaust ports 9d, 9e, extends along the edge of the opening of the first exhaust port 9d, and It protrudes from the top wall at a predetermined height.

  With the above configuration, in the secondary air supply device 30, when the air control valve 35 is opened, the secondary air flows from the nozzle 35a toward the opening of the first exhaust port 9d as shown in FIG. It is injected in a direction away from the second exhaust port 9d. In that case, as will be described later, the ECU 2 controls the air control valve 35 to open at the end of the valve opening period of the exhaust valve 5 (see FIG. 6), and the secondary injected from the nozzle 35a. Since the air pressure P2A is controlled to a value that can surely scavenge the residual gas in the cylinder 3a, the secondary air injected from the nozzle 35a flows into the cylinder 3a from the opening of the first exhaust port 9d.

  The secondary air flowing into the cylinder 3a from the first exhaust port 9d is guided by the guide wall 3e so as to flow toward the first intake port 8d without flowing toward the second exhaust port 9e. At that time, since the piston 3b is relatively raised to the vicinity of the top dead center because of the end of the valve opening period of the exhaust valve 5, the secondary air is indicated by arrows Y1 to Y3 in FIG. Then, along the top surface (not shown) of the piston 3b and the inner wall of the cylinder 3a, the gas flows in the vicinity of the opening of the first intake port 8d, the vicinity of the opening of the second intake port 8e, and the vicinity of the opening of the second exhaust port 9d. After that, it flows into the second exhaust port 9d. Thereby, the residual gas in the cylinder 3a is scavenged.

  An accelerator opening sensor 24 is connected to the ECU 2. The accelerator opening sensor 24 detects a depression amount (hereinafter referred to as “accelerator opening”) AP of an accelerator pedal (not shown) of the vehicle, and outputs a detection signal indicating it to the ECU 2.

  On the other hand, the ECU 2 is composed of a microcomputer including a CPU, a RAM, a ROM, an I / O interface (all not shown), and various kinds of signals according to the detection signals of the various sensors 20 to 24 described above. The control process is executed. Specifically, the secondary supercharging control process and the secondary air control process are executed as described below. In the present embodiment, the ECU 2 corresponds to secondary air control means.

  Next, the secondary supercharging control process described above will be described with reference to FIG. This control process controls the supercharging operation of the secondary air by the electric supercharger 32, and is executed by the ECU 2 at a predetermined control cycle (for example, 5 msec).

  As shown in the figure, first, in step 1 (abbreviated as “S1” in the figure, the same applies hereinafter), it is determined whether or not the secondary supercharging flag F_CHARGE is “1”. The secondary supercharging flag F_CHARGE is set to “1” when the execution condition of the secondary supercharging control process is satisfied in the determination process (not shown), and is set to “0” otherwise. .

  When the determination result of step 1 is NO, this process is finished as it is. On the other hand, when the determination result in step 1 is YES, it is determined that the secondary supercharging control process should be executed, the process proceeds to step 2, and the target secondary air pressure PA2_CMD is calculated. This target secondary air pressure PA2_CMD is a target value of the secondary air pressure PA2, and specifically, a map (not shown) is shown in accordance with operating state parameters such as the intake pressure PB, the engine speed NE, and the exhaust pressure PEX. Calculated by searching.

  Next, in step 3, a control input signal corresponding to the target secondary air pressure PA2_CMD is supplied to the supercharger motor 32a, and after this is driven, this process is terminated. Thus, the secondary air pressure PA2 is controlled to become the target secondary air pressure PA2_CMD.

  Next, the secondary air control process described above will be described with reference to FIG. This control process controls the valve opening period of the air control valve 35, that is, the period during which the secondary air is supplied into the cylinder 3a. The

  As shown in the figure, first, in step 10, it is determined whether or not the valve opening flag F_VOOPEN is “1”. The valve opening flag F_VOOPEN indicates whether or not the air control valve 35 is in an open state, and its value is set as described later.

  If the determination result in step 10 is NO and the air control valve 35 is in the closed state, the process proceeds to step 11 to determine whether or not the control condition flag F_SCAVE is “1”. This control condition flag F_SCAVE indicates whether or not the execution condition of the secondary air control process is established. In the determination process (not shown), the engine 3 is not stopped and the fuel cut operation is not performed. It is set to “1” when the execution condition of the secondary air control process is satisfied, and is set to “0” otherwise.

  When the determination result of step 11 is NO, this process is ended as it is. On the other hand, if the determination result in step 11 is YES and the execution condition of the secondary air control process is satisfied, the process proceeds to step 12 to determine whether or not the valve opening angle calculated flag F_CAxCAL is “1”. .

  When the determination result is NO, it is determined that the valve opening angle CAx of the air control valve 35 should be calculated, the process proceeds to step 13, and the valve opening angle CAx of the air control valve 35 is calculated. The valve opening angle CAx represents the timing at which the air control valve 35 is to be opened by the crank angle CA, and is calculated by the method described below.

  First, a valve opening period of the air control valve 35 is calculated as a crank angle section by searching a map (not shown) according to operating state parameters such as the intake pressure PB, the engine speed NE, and the exhaust pressure PEX. Then, the valve opening angle CAx of the air control valve 35 is calculated based on the calculated valve opening period and the aforementioned predetermined valve closing angle CA1.

  In step 14 subsequent to step 13, in order to indicate that the valve opening angle CAx of the air control valve 35 has been calculated, the valve opening angle calculated flag F_CAxCAL is set to “1”, and then the process proceeds to step 15. As described above, when the valve opening angle calculated flag F_CAxCAL is set to “1” in step 14, the determination result in step 12 described above becomes YES at the next and subsequent control timings. In this case, the process proceeds to step 15. .

  In step 15 following the above step 12 or 14, it is determined whether or not the crank angle CA has become the valve opening angle CAx. When this determination result is NO, this process is terminated as it is.

  On the other hand, when the determination result in step 15 is YES and CA = CAx, it is determined that the air control valve 35 should be opened, and the process proceeds to step 16 to drive the air control valve 35 to the open state. To do. Next, the routine proceeds to step 17 where the valve opening flag F_VOPEEN is set to “1” in order to indicate that the air control valve 35 is in an open state, and then this processing is terminated.

  As described above, when the valve opening flag F_VOOPEN is set to “1” in step 17, the determination result in step 10 described above becomes YES at the next and subsequent control timings. In this case, the process proceeds to step 18, and the crank angle is increased. It is determined whether or not CA has reached the aforementioned predetermined valve closing angle CA1. When this determination result is NO, this process is terminated as it is.

  On the other hand, if the determination result in step 18 is YES and CA = CA1, it is determined that the air control valve 35 should be closed, and the process proceeds to step 19 where the air control valve 35 is driven to the closed state. To do. Thereby, the valve opening period of the air control valve 35 is a section of the crank angle CA indicated by hatching in FIG.

  Next, in step 20, in order to indicate that the air control valve 35 is in a closed state, a valve opening flag F_VOOPEN is set to “0”. Next, the process proceeds to step 21 where the valve opening angle calculated flag F_CAxCAL described above is set to “0”, and then the present process is terminated.

  As described above, according to the control device 1 of the present embodiment, in the secondary supercharging control process, the secondary air pressure PA2 is controlled to a value that can reliably scavenge the residual gas in the cylinder 3a. In the secondary air control process, the valve opening period of the air control valve 35 is set to a predetermined value with the valve opening angle CAx shown in FIG. It is set between the valve closing angle CA1. During the valve opening period, the air control valve 35 is opened, so that secondary air is injected from the nozzle 35a of the air control valve 35 into the first exhaust port 9d.

  In this case, the secondary air is injected from the nozzle 35a in the direction away from the second exhaust port 9e toward the inside of the cylinder 3a with the secondary air pressure PA2 as described above, so that it is opened by the exhaust valve 5. After flowing into the cylinder 3a from the first exhaust port 9d, it is guided to the first intake port 8d side by the guide wall 3e. The guide wall 3e is disposed at a portion between the opening of the first exhaust port 9d and the opening of the second exhaust port 9e, and protrudes from the top wall of the cylinder 3a toward the piston 3b, so that the first exhaust port 9d The secondary air that has flowed into the cylinder 3a is reliably guided to the first intake port 8d side while being prevented from flowing to the opening side of the second exhaust port 9e.

  As a result, as indicated by arrows Y1 to Y3 in FIG. 5, the secondary air flows in the order of the vicinity of the opening of the first intake port 8d, the vicinity of the opening of the second intake port 8e, and the vicinity of the opening of the second exhaust port 9e. After circulating inside, it flows out from the second exhaust port 9e to the exhaust passage 9. As described above, the residual gas in the cylinder 3a can be efficiently scavenged by the secondary air, and the scavenging efficiency of the residual gas can be improved. Thereby, combustion efficiency can be improved and the generation output and fuel consumption of the engine 3 can be improved. Moreover, the occurrence of knocking can be suppressed by improving the scavenging efficiency of the residual gas. In addition to this, the secondary air flows to the exhaust passage 9 side together with the residual gas, and the air-fuel ratio of the exhaust gas becomes the lean side, so that the air-fuel ratio of the air-fuel mixture can be controlled to the rich side, and thereby The occurrence of knocking can be further suppressed. As a result, since the compression ratio of the air-fuel mixture can be set higher, the combustion efficiency can be further improved, and the generated output and fuel consumption of the engine 3 can be further improved.

  Further, in an engine with a turbocharger such as the engine 3 of the present embodiment, even when the engine is in a transient operation state during acceleration and the intake pressure PB <exhaust pressure PEX is satisfied, the secondary air supply device 30 causes the residual gas to be discharged. A scavenging operation can be performed. Thereby, the amount of intake air can be increased, and the turbo response can be improved. For the same reason, the ignition timing can be controlled to the more advanced side, and the generated output can be improved. As a result, high merchantability can be ensured.

  In addition, although embodiment is the example which set the supply period of the secondary air by a secondary air supply apparatus to the period shown by hatching in FIG. 6, the supply period of the secondary air by the secondary air supply apparatus of this invention is However, the present invention is not limited to this. For example, when the internal combustion engine is provided with a valve timing changing mechanism that changes the valve timing of the intake valve and / or the exhaust valve, the two exhaust valves can be used regardless of the valve overlap of the intake valve and the exhaust valve. Secondary air may be supplied at the end of the valve opening period. Further, in a situation where the valve overlap is very large, the secondary air may be supplied at the end of the opening period of the two exhaust valves and in a period in which the residual gas does not blow back to the intake valve side. .

  The embodiment is an example in which the air in the intake chamber 8b is supplied to the first exhaust port 9d as the secondary air supply device, but the secondary air supply device of the present invention is not limited to this. Any secondary air may be supplied to one of the two exhaust ports toward the inside of the cylinder in a direction away from the other of the two exhaust ports. For example, a device that supplies air in the atmosphere to one intake port may be used as the secondary air supply device.

  Further, the embodiment is an example in which the guide wall 3e is used as the guide portion, but the guide portion of the present invention is not limited to this, and the opening of one exhaust port and the opening of the other exhaust port of the top wall of the cylinder. It is sufficient if it is provided in a portion between and the secondary air is guided to the intake valve side. For example, you may provide a mask-shaped member as a guide part.

  The embodiment is an example in which two intake valves 4 and 4 are provided for each cylinder 3a as intake valves of an internal combustion engine. However, the number of intake valves of the present invention is not limited to this, and one intake valve or Three or more intake valves may be provided for each cylinder.

  Furthermore, although embodiment is the example which applied the control apparatus 1 of this invention to the internal combustion engine 3 for vehicles, the control apparatus of this invention is not restricted to this, For internal combustion engines for ships, and other industrial equipment Needless to say, the present invention can also be applied to other internal combustion engines.

1 control device 2 ECU (secondary air control means)
3 Internal combustion engine 3a Cylinder 3b Piston 3e Guide wall (guide part)
4 Intake valve 5 Exhaust valve 9d First exhaust port (one exhaust port)
9e Second exhaust port (the other exhaust port)
30 Secondary air supply device

Claims (2)

A control device for an internal combustion engine having two exhaust valves for opening and closing two exhaust ports and an intake valve for each cylinder,
A secondary air supply device that supplies secondary air in a direction away from the other of the two exhaust ports toward the inside of the cylinder with respect to one of the two exhaust ports opened and closed by one of the two exhaust valves; ,
In order to scavenge residual gas in the cylinder, the secondary air supply device is controlled to supply the secondary air to the one exhaust port at the end of the opening period of the two exhaust valves. Secondary air control means;
A control device for an internal combustion engine, comprising:   A guide portion for guiding the secondary air to the intake valve side is provided in a portion of the top wall of the cylinder between the opening of the one exhaust port and the opening of the other exhaust port. The control apparatus for an internal combustion engine according to claim 1.

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