JP2006194096A - Controller for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for an internal combustion engine capable of smoothly switching an operation system from four cycle spark ignition operation to two cycle self-ignition operation. <P>SOLUTION: When this electric controller 70 switches an operation system of an arbitrary cylinder to a two cycle self-ignition operation system from a four cycle spark ignition operation system, it changes a period of scavenging or amount of fuel injection in accordance with a condition of a suction valve and an exhaust valve of the other cylinder. For example, when switching operation of a first cylinder to the two cycle self-ignition operation system, a scavenging process of the first cylinder shown by mark C is overlapped on a suction process by the four cycle spark ignition operation system of a second cylinder shown by mark B. For this reason, new air to be introduced into the first cylinder is taken up by the second cylinder and amount of scavenging of the first cylinder becomes short. Therefore, the electric controller raises supercharging pressure in the period to make amount of scavenging of the first cylinder sufficient. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for a multi-cylinder internal combustion engine including a plurality of cylinders that can be operated by a four-cycle spark ignition operation method and a two-cycle self-ignition operation method.

Conventionally, a four-cycle spark ignition operation system that repeats an exhaust stroke, an intake stroke, a compression stroke, and a combustion stroke by spark ignition every time the crank angle rotates 720 degrees, and an exhaust stroke, scavenging every time the crank angle rotates 360 degrees There is known a multi-cylinder internal combustion engine including a plurality of cylinders that can be operated by a two-cycle self-ignition operation method that repeats a combustion stroke by a stroke, an intake stroke, a compression stroke, and self-ignition (self-ignition) ( For example, see Patent Document 1.)
JP 2003-83118 A (Claim 7)

  By the way, in the two-cycle self-ignition operation, it is necessary to leave a desired amount of combustion gas in the cylinder in order to ensure a desired amount of fresh air or to start self-ignition at a desired time. Therefore, the conventional control device determines the opening and closing timings of the intake valve and the exhaust valve (hereinafter also referred to as “valve timing”) based on parameters (for example, accelerator pedal operation amount and engine speed) representing the required torque. It is supposed to be. In other words, the exhaust stroke, the scavenging stroke, and the intake stroke in the two-cycle self-ignition operation are started or ended when the crank angle reaches a predetermined crank angle for each stroke that is predetermined according to the required torque. The

  Accordingly, when all the cylinders are constantly operated by the two-cycle self-ignition operation method (hereinafter also referred to as “two-cycle steady operation”), if the required torque for the internal combustion engine does not change, The opening / closing timing of the cylinder intake and exhaust valves does not change. Therefore, the intake state (for example, the intake state determined by the state of the intake valve of the other cylinder) and the exhaust state (for example, the exhaust state determined by the state of the exhaust valve of the other cylinder) when the stroke of a certain cylinder becomes the scavenging stroke The state) is substantially constant as long as the required torque for the internal combustion engine does not change.

  However, in a multi-cylinder internal combustion engine, when the operation method is switched from the operation using the four-cycle spark ignition operation method to the operation using the two-cycle spark ignition operation method, the operation method is sequentially switched for each cylinder. In the period until the operation is performed by the two-cycle self-ignition operation method, the cylinders operated by the two-cycle self-ignition operation method and the cylinders operated by the four-cycle spark ignition operation method are mixed.

  In such a period, since the intake state and the exhaust state when a certain cylinder is in the scavenging stroke are different from the intake state and the exhaust state in the two-cycle steady operation, the scavenging period is the scavenging in the two-cycle steady operation. If the same period as the period is set, the scavenging amount may be too small or too large. As a result, there is a problem that the amount of combustion gas remaining in the cylinder (internal EGR amount) fluctuates, the start timing of self-ignition fluctuates, and the generated torque fluctuates.

  Accordingly, one of the objects of the present invention is a control device for an internal combustion engine that can reduce fluctuations in torque generated by the engine when the operation method is switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method. Is to provide.

  In order to achieve this object, a control apparatus for an internal combustion engine according to the present invention includes a four-cycle spark ignition operation system that repeats an exhaust stroke, an intake stroke, a compression stroke, and a combustion stroke by spark ignition every time the crank angle rotates 720 degrees, It has a plurality of cylinders that can be operated by a two-cycle self-ignition operation system that repeats an exhaust stroke, a scavenging stroke, an intake stroke, a compression stroke, and a combustion stroke by self-ignition every time the crank angle rotates 360 degrees. The present invention is applied to a multi-cylinder internal combustion engine and includes an operation method determining means, a valve timing control means, and a scavenging amount control means.

  The operation method determining means determines whether the operation method of each cylinder should be the four-cycle spark ignition operation method or the two-cycle self-ignition operation method based on the operation state of the engine. For example, the operation method determining means may display a map that divides an operation region that should be operated in the four-cycle spark ignition operation method and an operation region that should be operated in the two-cycle self-ignition operation method based on the required torque and the engine speed. An operation method to be executed is determined based on which region of the map the current engine operating state determined by the current required torque and the engine rotational speed is located.

  The valve timing control means controls the opening / closing timing (valve timing) of each intake valve and each exhaust valve of the plurality of cylinders based on the torque required for the engine and the determined operation method. Thus, when the four-cycle spark ignition operation method is to be performed, the exhaust stroke, the intake stroke, the compression stroke, and the combustion stroke by the spark ignition are repeated every time the crank angle rotates 720 degrees. When the two-cycle self-ignition operation method is to be performed, the exhaust stroke, the scavenging stroke, the intake stroke, the compression stroke, and the combustion stroke by self-ignition are repeated every time the crank angle rotates 360 degrees.

  The scavenging amount control means controls a factor that determines the scavenging amount at the time when the operation mode of the cylinder starts to be switched from the 4-cycle spark ignition operation mode to the 2-cycle self-ignition operation mode. The scavenging amount is the amount of gas discharged from the cylinder in the scavenging stroke during the scavenging stroke in the two-cycle self-ignition operation method. Specifically, the scavenging amount control means requires the scavenging amount at the same time when the cylinder operation method starts to be switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method. The factor for determining the scavenging amount is controlled so as to approach the scavenging amount at the time when the operation by the two-cycle self-ignition operation method is constantly performed by the valve timing control means under the same torque as the torque being .

  For example, when the scavenging stroke of the same cylinder is started to start switching the operation method of a cylinder from a 4-cycle spark ignition operation method to a 2-cycle auto-ignition operation method, the other cylinders are operated in a 4-cycle spark ignition operation method. When the engine is in the intake stroke, the intake state is different from that in the two-cycle steady operation, and a large amount of fresh air is sucked into the cylinder in the intake stroke, so the scavenging amount of the cylinder in the scavenging stroke is insufficient. .

  Alternatively, when the scavenging stroke of the cylinder is started in order to start switching the operation method of a cylinder from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, if it is in the 2-cycle steady operation, immediately before the scavenging stroke. While the other cylinders have a scavenging stroke, the other cylinders are operating in the 4-cycle spark ignition operation method, so the compression stroke and the combustion stroke are in the 4-cycle spark ignition operation method. There may be cases. At this time, the exhaust pressure (exhaust pipe pressure) is lower than the exhaust pressure in the two-cycle steady operation, and the exhaust state is different from that in the two-cycle steady operation. Therefore, the scavenging amount of the cylinder in the scavenging stroke is excessive. May be.

  On the other hand, according to the control device according to the present invention provided with the scavenging amount control means, the scavenging amount is controlled by controlling the factor (supercharging pressure or scavenging period to be described later) that determines the scavenging amount in such a case. Is the appropriate amount. As a result, the present control device can reduce fluctuations in torque generated by the engine when the operation method is switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method.

In this case, the control device for the internal combustion engine is
A supercharging pressure control means for controlling the supercharging pressure of the engine based on the torque required for the engine and the determined operation method;
The scavenging amount control means includes
When the operation mode of the cylinder starts to be switched from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, the scavenging stroke of any cylinder that starts operation by the 2-cycle self-ignition operation method is the same as the 4-cycle spark ignition method. In the case where it overlaps with the intake stroke of another cylinder operated by the operation method, the supercharging pressure is the same two-cycle auto-ignition operation method under the same torque as that required for the engine at the same time. By controlling the supercharging pressure control means so as to be larger than the supercharging pressure controlled by the supercharging pressure control means at the time when the operation by is constantly performed, the supercharging pressure is reduced to the scavenging amount. May be configured to control as a factor that determines.

  According to this, when the scavenging stroke of an arbitrary cylinder that starts operation by the two-cycle self-ignition operation method overlaps with the intake stroke of another cylinder that is operated by the four-cycle spark ignition operation method, the supercharging pressure becomes two cycles. It becomes higher than during steady operation. As a result, fresh air is introduced into the cylinders in the scavenging stroke so as to compensate for fresh air taken by the cylinders in the intake stroke operated by the four-cycle spark ignition operation method, and a sufficient scavenging amount is secured.

  On the other hand, as described above, the scavenging amount control means may be configured to change the opening / closing timing of each intake valve and each exhaust valve of the plurality of cylinders as a factor for determining the scavenging amount.

  According to this, when switching the operation from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method, the valve timing is controlled to be different from that in the two-cycle steady operation. As a result, an appropriate scavenging amount can be easily ensured.

The scavenging amount control means includes:
At the time of starting to switch the operation mode of the cylinder from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, during the scavenging stroke of any cylinder that starts operation by the 2-cycle self-ignition operation method and immediately before the scavenging stroke It is preferable that the opening / closing timing of the intake valve and the exhaust valve of the arbitrary cylinder is changed in accordance with the open / close state of the intake valve and the exhaust valve of the other cylinder.

  According to this, the opening and closing states (that is, the intake state and the exhaust state) of the intake valves and the exhaust valves of the other cylinders during the scavenging stroke of any cylinder that starts the operation by the two-cycle self-ignition operation method and immediately before the scavenging stroke Accordingly, the opening / closing timings of the intake valves and exhaust valves of the arbitrary cylinders are changed. As a result, an appropriate scavenging amount can be easily ensured.

Further, in this case, the scavenging amount control means
When the operation mode of the cylinder starts to be switched from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, the scavenging stroke of any cylinder that starts operation by the 2-cycle self-ignition operation method is the same as the 4-cycle spark ignition method. If it overlaps with the intake stroke or exhaust stroke of another cylinder operated by the operation method, the same scavenging stroke period is the same two cycles under the same torque as that required for the engine at the same time. The intake valve opening timing of any cylinder and the scavenging stroke at the time when the operation by the self-ignition operation system is steadily performed by the valve timing control means, and a predetermined extension period is added. It is preferable that at least one of the exhaust valve closing timings of the same cylinder be changed.

  According to this, when the scavenging stroke of an arbitrary cylinder that starts operation by the two-cycle self-ignition operation method overlaps with the intake stroke of another cylinder that is operated by the four-cycle spark ignition operation method, the scavenging period is steady for two cycles. The scavenging period during operation can be extended. As a result, “the amount by which the scavenging amount of the cylinder to be switched to the two-cycle self-ignition operation decreases due to the fresh air taken by the cylinder in the intake stroke operated by the four-cycle spark ignition operation method” is compensated. Since the scavenging stroke of the cylinder is extended, a sufficient scavenging amount can be ensured.

  In addition, when the scavenging stroke of any cylinder that starts operation by the two-cycle self-ignition operation method overlaps with the exhaust stroke of another cylinder that is operated by the four-cycle spark ignition operation method, the scavenging period is the same as that in the two-cycle steady operation. It can be extended beyond the scavenging period. As a result, “the amount by which the scavenging amount of the cylinder to be switched to the two-cycle self-ignition operation is reduced by the combustion gas discharged from the cylinder in the exhaust stroke operated by the four-cycle spark ignition operation method” is compensated. Since the scavenging stroke of the cylinder is extended, a sufficient scavenging amount can be secured.

The scavenging amount control means includes:
Other than occurring at the time of starting to switch the operation mode of the cylinder from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, immediately before the combustion stroke of any cylinder that starts operation by the 2-cycle self-ignition operation method When the combustion in the combustion stroke of the cylinder is combustion by the 4-cycle spark point operation method, the scavenging stroke period is the same under the same torque as that required for the engine at the same time. The intake valve opening of any cylinder is set so as to be a period obtained by subtracting a predetermined shortening period from the scavenging stroke period at the time when the operation by the two-cycle self-ignition operation system is steadily performed by the valve timing control means. It is preferable that at least one of the timing and the exhaust valve closing timing of the arbitrary cylinder be changed.

  In the two-cycle steady operation, the scavenging stroke of any cylinder is continuous with the scavenging stroke of the other cylinder having the combustion stroke immediately before the combustion stroke of the same cylinder, or starts before the scavenging stroke of the other cylinder ends. To do. On the other hand, other cylinders that are generated immediately before combustion of any cylinder that starts operation by the two-cycle self-ignition operation method at the time when the operation method is switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method. When the combustion of this is the combustion by the 4-cycle spark point operation method, the scavenging period of the other cylinder does not exist immediately before the scavenging stroke of the arbitrary cylinder, and the intake valves and exhaust valves of the other cylinders are closed. Is in a state. In this case, at the start of the scavenging stroke of an arbitrary cylinder, at least the exhaust pressure is lower than that during the two-cycle steady operation, so that scavenging is easy. Therefore, if the scavenging period of an arbitrary cylinder is the same scavenging period as in the two-cycle steady operation, the scavenging amount becomes excessive.

  On the other hand, according to the above configuration, the scavenging stroke period is “the torque required for the engine at the time when the operation method is switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method. So that it becomes a period obtained by subtracting a predetermined shortening period from the period of the scavenging stroke at the time when the operation by the same two-cycle self-ignition operation method is constantly performed by the valve timing control means under the same torque. Valve timing is controlled. As a result, the scavenging amount of an arbitrary cylinder that starts operation by the two-cycle self-ignition operation method can be set to an appropriate amount.

Further, the scavenging amount control means includes:
The exhaust valve closing timing of the cylinder in which the exhaust valve opening timing of the cylinder that performs combustion after the two cylinders that continuously perform combustion by the two-cycle self-ignition operation method is the first of the two cylinders that performs combustion It is preferable that the exhaust valve opening timing of a cylinder that performs combustion thereafter is changed so that it comes later than the timing.

Similarly, the scavenging amount control means includes
The exhaust valve closing timing of the cylinder in which the exhaust valve opening timing of the cylinder that performs combustion after the two cylinders that continuously perform combustion by the two-cycle self-ignition operation method is the first of the two cylinders that performs combustion It is preferable that the exhaust valve closing timing of the cylinder that performs combustion earlier is changed so as to arrive later than the timing.

  As described above, when the operation mode is switched from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, the scavenging period of an arbitrary cylinder is extended, and as a result, the extended scavenging period has the same combustion order. May overlap in time with the scavenging period of other cylinders immediately before or immediately after. In this case, the scavenging amount of an arbitrary cylinder is reduced by increasing the exhaust pressure because combustion gas is discharged from the other cylinders.

  On the other hand, according to the above configuration, the scavenging periods of the two cylinders that perform combustion by the two-cycle self-ignition operation method do not overlap in time, so at least the exhaust valve opening timing or the exhaust valve closing timing is The scavenging amount of the cylinder that has not been changed becomes a scavenging amount close to the intended scavenging amount.

Furthermore, the control device for the internal combustion engine includes:
Fuel injection control means for determining a fuel injection amount based on the torque required for the engine and the determined operation method, and injecting the determined fuel injection amount into the cylinder in the combustion stroke When,
When the scavenging amount control means controls the exhaust valve closing timing of an arbitrary cylinder that starts operation by the two-cycle self-ignition operation method, the fuel injection control means according to the controlled exhaust valve closing timing Injection timing control means for changing the injection start timing of the fuel injected from
Is preferably provided.

  According to this, for example, when the exhaust valve closing timing is retarded by the scavenging amount control means and the scavenging period is extended, the fuel injected timing is changed (retarded) so that the injected fuel is exhausted. Occurrence of the phenomenon of being discharged out of the cylinder through the so-called (so-called “fuel blow-through phenomenon”) can be prevented. Further, even if the exhaust valve closing timing is advanced to avoid interference in the scavenging period between a plurality of cylinders, by changing (advancing) the fuel injection timing, It is possible to reliably form an air-fuel mixture that is uniformly mixed with each other.

  The control device for another internal combustion engine according to the present invention is applied to a multi-cylinder internal combustion engine having a plurality of cylinders that can be operated by the above-described 4-cycle spark ignition operation method and the 2-cycle self-ignition operation method. The The control device for the internal combustion engine includes an operation method determining means, a valve timing control means, a fuel injection control means, and a switching fuel injection amount control means.

The operation method determining means determines whether the operation method of each cylinder should be the four-cycle spark ignition operation method or the two-cycle self-ignition operation method based on the operation state of the engine.
The valve timing control means controls the opening / closing timings of the intake valves and the exhaust valves of the plurality of cylinders based on the torque required for the engine and the determined operation method.

  The fuel injection control means determines a fuel injection amount based on the torque required for the engine and the determined operation method, and supplies the determined fuel injection amount of fuel to the cylinder that reaches the combustion stroke. Spray.

  The fuel injection amount control means at the time of switching is such that the fuel injection amount for the cylinder at the time of starting to switch the cylinder operation method from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method From the fuel injection amount at the time when the valve timing control means and the fuel injection control means are steadily operated by the two-cycle self-ignition operation method under the same torque as that required for Also, the fuel injection amount for the cylinder is changed so that the fuel injection amount is reduced by a predetermined amount.

  When an operation system of a cylinder is to be switched from the 4-cycle spark ignition operation system to the 2-cycle auto-ignition operation system, the combustion gas remaining in the cylinder is combustion gas by the 4-cycle spark ignition operation system. Since this combustion gas is hotter than the combustion gas in the two-cycle steady operation, when the same amount of fuel is injected as in the two-cycle steady operation, the combustion generated by the combustion in the first two-cycle operation mode of the cylinder The gas temperature is also higher than the combustion gas temperature during the two-cycle steady operation. Therefore, the combustion gas temperature in the next cycle is also higher than the combustion gas temperature in the two-cycle steady operation. As a result, it may take several cycles for the combustion gas temperature to converge to the combustion gas temperature during the two-cycle steady operation after switching the operation method to the two-cycle self-ignition operation method. There is a problem that the torque fluctuates due to, for example, being advanced more than the proper ignition timing.

  On the other hand, according to the above configuration, the fuel injection amount for the cylinder at the time of starting the switching of the operation system from the 4-cycle spark ignition operation system to the 2-cycle self-ignition operation system is required for the engine at the same time. Fuel injection amount (basic fuel injection amount) at the time when the valve timing control means and the fuel injection control means are steadily operated under the same torque as the torque being operated by the two-cycle self-ignition operation method The fuel injection amount is smaller by a predetermined amount. As a result, the increase in the combustion gas temperature by the first two-cycle operation method after switching the operation method is suppressed, and the two-cycle self-ignition operation method using the combustion gas at the same temperature as the two-cycle steady operation from the next cycle. Driving is performed. Accordingly, since self-ignition can be generated at an ideal time immediately after switching the driving method, torque fluctuations can be suppressed.

In this case, the switching fuel injection amount control means is
At the time of starting to switch the operation mode of the cylinder from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, during the scavenging stroke of any cylinder that starts operation by the 2-cycle self-ignition operation method and immediately before the scavenging stroke It is preferable that the predetermined amount is changed in accordance with the open / close states of the intake valves and exhaust valves of the other cylinders. In this case, the predetermined amount includes not only a positive amount but also a negative amount. That the predetermined amount is a negative amount means that the basic fuel injection amount is increased.

  According to this, the opening and closing states (that is, the intake state and the exhaust state) of the intake valves and the exhaust valves of the other cylinders during the scavenging stroke of any cylinder that starts the operation by the two-cycle self-ignition operation method and immediately before the scavenging stroke Accordingly, the fuel injection amount for the arbitrary cylinder is controlled. As a result, even if the cylinder operated by the two-cycle self-ignition operation method and the cylinder operated by the four-cycle spark ignition operation method coexist and the scavenging amount is different from that in the two-cycle steady operation, The temperature of the combustion gas generated by the ignition combustion can be set to a temperature equivalent to the combustion gas temperature during the two-cycle steady operation.

Further, another control device for an internal combustion engine according to the present invention is applied to the multi-cylinder internal combustion engine, and includes the operation method determining means, the valve timing control means, and the fuel injection control means.
At the time when the operation mode of the cylinder starts to be switched from the 4-cycle spark ignition operation mode to the 2-cycle self-ignition operation mode, during the scavenging stroke or immediately before the scavenging stroke of any cylinder that starts operation by the 2-cycle self-ignition operation mode In the case where there is no scavenging stroke of other cylinders, the scavenging amount which is the amount of gas discharged from the cylinder in the scavenging stroke during the scavenging stroke in the two-cycle self-ignition operation method When the scavenging amount is the same as the torque required for the engine at the same time, the operation by the two-cycle self-ignition operation system is steadily performed by the valve timing control means and the fuel injection control means. A scavenging amount control means for controlling a factor that determines the scavenging amount so as to approach the scavenging amount at the time of being performed;
When the operation mode of the cylinder starts to be switched from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, the scavenging stroke of any cylinder that starts operation by the 2-cycle self-ignition operation method is the same as the 4-cycle spark ignition method. When it overlaps with the intake stroke or exhaust stroke of another cylinder operated by the operation method, the fuel injection amount for the arbitrary cylinder is under the same torque as the torque required for the engine at the same time. The fuel injection amount is set so that the fuel injection amount is different from the fuel injection amount at the time when the operation by the two-cycle self-ignition operation method is regularly performed by the valve timing control means and the fuel injection control means. A switching fuel injection amount control means to be changed;
It has.

  According to this, when there is no scavenging stroke of another cylinder during or immediately before the scavenging stroke of any cylinder to be switched to the two-cycle self-ignition operation method, a factor for determining the scavenging amount (for example, , Supercharging pressure and / or scavenging period). In such a case, the scavenging amount can be easily adjusted by changing the factor that changes the scavenging amount, so that the torque fluctuation at the time of switching the operation method is suppressed while obtaining the required torque without changing the fuel injection amount. can do.

  On the other hand, when the scavenging stroke of an arbitrary cylinder to be switched to the two-cycle self-ignition operation method overlaps with the intake stroke or the exhaust stroke of another cylinder operated by the four-cycle spark ignition operation method, the fuel injection amount is adjusted. The In such a case, even if the factor for changing the scavenging amount is changed, the scavenging amount is unlikely to change due to the fact that fresh air is taken away by other cylinders or combustion gas is discharged from other cylinders. It is advantageous to bring the combustion gas temperature closer to the combustion gas temperature during two-cycle steady operation by adjusting the amount. Accordingly, the combustion gas temperature at the start of the two-cycle self-ignition operation becomes an appropriate temperature, so that the next self-ignition combustion is also stably performed. As a result, the cycle-to-cycle variation in torque generated by the engine can be suppressed.

  Hereinafter, embodiments of a control device for an internal combustion engine according to the present invention will be described with reference to the drawings. The control device of each embodiment is applied to a multi-cylinder internal combustion engine including a plurality of cylinders that can be operated by a four-cycle spark ignition operation method and a two-cycle self-ignition operation method.

  The 4-cycle spark ignition operation method is an operation method in which an exhaust stroke, an intake stroke, a compression stroke, and a combustion stroke by spark ignition using a spark plug are repeated every time the crank angle rotates 720 degrees. The two-cycle self-ignition operation method is an operation method in which an exhaust stroke, a scavenging stroke, an intake stroke, a compression stroke, and a combustion stroke by self-ignition (self-ignition) are repeated every time the crank angle rotates 360 degrees.

  FIG. 1 schematically shows a system in which an internal combustion engine control apparatus according to an embodiment of the present invention is applied to the internal combustion engine 10 described above. The internal combustion engine 10 has three cylinders. Combustion in the four-cycle spark ignition operation method is performed in the order of the first cylinder, the third cylinder, and the second cylinder. Combustion in the two-cycle self-ignition operation method is performed in the order of the first cylinder, the second cylinder, and the third cylinder. FIG. 1 shows only a cross section of a specific cylinder, but the other cylinders have the same configuration.

  The internal combustion engine 10 includes a cylinder block unit 20 including a cylinder block, a cylinder block lower case, an oil pan, and the like, a cylinder head unit 30 fixed on the cylinder block unit 20, and the cylinder block unit 20 and the cylinder head unit 30. An intake system 40 for supplying air (fresh air) and an exhaust system 50 for releasing exhaust gas from the cylinder block 20 and the cylinder head 30 to the outside are included.

  The cylinder block unit 20 includes a cylinder 21, a piston 22, a connecting rod 23, and a crankshaft 24. The piston 22 reciprocates in the cylinder 21, and the reciprocating motion of the piston 22 is transmitted to the crankshaft 24 through the connecting rod 23, whereby the crankshaft 24 rotates. The heads of the cylinder 21 and the piston 22 form a combustion chamber 25 together with the cylinder head portion 30.

  The cylinder head portion 30 includes an intake port 31 that communicates with the combustion chamber 25, an intake valve (supply valve) 32 that opens and closes the intake port 31, an intake valve drive mechanism 32 a that drives the intake valve 32, and an exhaust that communicates with the combustion chamber 25. Port 33, exhaust valve 34 for opening and closing exhaust port 33, exhaust valve drive mechanism 34a for driving exhaust valve 34, ignition plug 35, igniter 36 including an ignition coil for generating a high voltage applied to ignition plug 35, and fuel (gasoline fuel) ) Is injected into the combustion chamber 25. The injector (fuel injection valve) 37 is provided. The intake valve drive mechanism 32a and the exhaust valve drive mechanism 34a are connected to a drive circuit 38, and in response to a signal from the drive circuit 38, a variable valve mechanism (open / close drive) for driving the intake valve 32 and the exhaust valve 34, respectively. For example, an electromagnetically driven valve system).

  The injector 37 is connected in order to a pressure accumulation chamber 37a, a fuel pump 37b, and a fuel tank (not shown). In response to the drive signal, the fuel pump 37b raises the fuel in the fuel tank to a high pressure and supplies it to the pressure accumulating chamber 37a. The pressure accumulating chamber 37a stores high-pressure fuel. Thereby, the injector 37 injects high-pressure fuel into the combustion chamber 25 when the valve 37 is opened in response to the drive signal. These constitute fuel injection means.

  The intake system 40 includes an intake manifold 41 that communicates with the intake port 31, a surge tank 42 that communicates with the intake manifold 41 and forms an intake pipe (air supply pipe), an intake duct 43 that has one end connected to the surge tank 42, an intake duct 43, an air filter 44, an air bypass valve 45 (hereinafter referred to as ABV 45), a supercharger (mechanical supercharger) disposed in the intake duct 43 in order from the other end portion toward the downstream (surge tank 42). ) 46, an intercooler 47 and a throttle valve 48.

  The supercharger 46 includes a supercharger clutch 46a. In response to the drive signal, the supercharger clutch 46a is in a state where the supercharger 46 is mechanically driven by the internal combustion engine 10 (operating state, that is, a supercharging state), and the supercharger 46 is not driven by the internal combustion engine 10. The state is switched to a non-operating state (that is, a non-supercharging state). The intercooler 47 is water-cooled and cools the air passing through the intake duct 43.

  The intake system 40 further includes a bypass passage 49. One end of the bypass passage 49 is connected to the ABV 45, and the other end is connected to the intake duct 43 at a position between the supercharger 46 and the intercooler 47. The ABV 45 can adjust the amount of air flowing into the supercharger 46 and the amount of air bypassing the supercharger 46 by changing a valve opening (not shown) in response to the drive signal.

  The throttle valve 48 is rotatably supported by the intake duct 43 in the intake duct 43. The throttle valve 48 is connected to a throttle valve actuator 48a that constitutes a throttle valve driving means. The throttle valve 48 is rotationally driven by a throttle valve actuator 48a to change the opening sectional area of the intake duct 43 (that is, the intake passage sectional area).

  The exhaust system 50 includes an exhaust pipe 51 including an exhaust manifold that communicates with the exhaust port 33 and forms an exhaust passage together with the exhaust port 33, and a three-way catalyst device 52 disposed in the exhaust pipe 51.

  On the other hand, this system includes an air flow meter 61, an outside air temperature sensor 62, a crank position sensor 63, a throttle valve opening sensor 64, an intake pipe pressure sensor 65, an intake air temperature sensor 66, and an accelerator opening sensor 67.

  The air flow meter 61 outputs a signal indicating the flow rate Ga of the sucked air. The outside air temperature sensor 62 outputs a signal representing the temperature (outside air temperature) Tatm of the air flowing into the engine (intake passage). The crank position sensor 63 outputs a narrow pulse every time the crankshaft 24 rotates by a certain minute angle (here, the crank angle is 1 degree = 1 CA). Based on this signal, the engine speed NE is determined. In addition, a reference position sensor (not shown) that outputs a pulse output from the crank position sensor 63 and one pulse each time the first cylinder reaches the compression top dead center when the first cylinder is operated by the four-cycle spark ignition operation method. The absolute crank angle is obtained by the pulse from. In other words, the absolute crank angle is reset to 0 degree (720 degrees) when the first cylinder is operating in the four-cycle spark ignition operation mode and becomes the compression top dead center. Each time the rotation angle increases by 1 degree, it increases by 1 degree.

  The throttle valve opening sensor 64 detects the opening of the throttle valve 48 and outputs a signal representing the throttle valve opening TA. The intake pipe pressure sensor 65 outputs a signal representing the pressure (intake pipe pressure) PM of the air in the intake pipe downstream of the throttle valve 48. The intake air temperature sensor 66 outputs a signal indicating the temperature (intake air temperature) THA of the air in the intake pipe. The accelerator opening sensor 67 outputs a signal representing the operation amount Accp of the accelerator pedal 68 operated by the driver.

  The electric control device 70 is a CPU 71 connected to each other by a bus, a ROM 72 pre-stored with programs executed by the CPU 71, tables (look-up tables, maps), constants, and the like, and the CPU 71 temporarily stores data as necessary. The microcomputer includes a RAM 73, a backup RAM 74 that stores data while the power is turned on, and retains the stored data while the power is shut off, an interface 75 including an AD converter, and the like.

  The interface 75 is connected to the sensors 61 to 67 and supplies signals from the sensors 61 to 67 to the CPU 71. The interface 75 is connected to the igniter 36, the injector 37, the fuel pump 37b, the drive circuit 38, the ABV 45, the supercharger clutch 46a, and the throttle valve actuator 48a, and sends a drive signal to them according to an instruction from the CPU 71. It has become.

  Next, the operation of the control device according to each embodiment configured as described above will be described. In the following description, a table labeled MapX (a, b) means a table that defines the relationship between the variable a, the variable b, and the value X. Further, obtaining the value X based on the table MapX (a, b) means obtaining (determining) the value X based on the current variable a, the current variable b, and the table MapX (a, b). Means.

(First embodiment)
The control device according to the first embodiment performs supercharging when the operation method is switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method (hereinafter also referred to as “4 cycle-2 cycle switching”). By increasing the pressure, the fluctuation amount of the torque generated by the internal combustion engine is reduced.

<During 4-cycle spark ignition operation>
First, the description starts when the operating state of the internal combustion engine 10 is constantly in the four-cycle spark ignition operation region. Note that the values of a flag X and a flag X2, which will be described later, are set to “0” in an initial routine (not shown) that is executed when the ignition key is changed from OFF to ON. The value of the flag X4 is set to “1” in the initial routine.

  The operation method determination routine shown by the flowchart in FIG. 2 is an operation that determines whether the operation method of each cylinder should be the 4-cycle spark ignition operation method or the 2-cycle self-ignition operation method based on the operation state of the engine 10. The system determination means is comprised. The CPU 71 is configured to repeatedly execute the driving method determination routine shown in FIG. 2 every elapse of a predetermined time. Accordingly, when the predetermined timing is reached, the CPU 71 starts processing from step 200, proceeds to step 205, and obtains the required torque Tqtgt based on the table MapTqtgt (Accp, NE). Next, the CPU 71 proceeds to step 210 to determine whether the current operation state (operation state determined by the required torque Tqtgt and the engine speed NE) is in the 4-cycle spark ignition operation region or the 2-cycle self-ignition operation region. The determination is made based on the map shown in step 210.

  Next, the CPU 71 proceeds to step 215 to determine whether or not the current operation state is within the two-cycle self-ignition operation region. According to the above assumptions, the current operating condition is in the four-cycle spark ignition operating region. Therefore, the CPU 71 makes a “No” determination at step 215 to proceed to step 220 to determine whether or not the engine operating state (previous operating state) when the routine was executed last time was within the two-cycle self-ignition operation region. Determine. If the above-mentioned assumption is followed, the last driving | running state will be in a 4-cycle spark ignition driving | running | working area | region. Accordingly, the CPU 71 makes a “No” determination at step 220 to proceed to step 295 to end the present routine tentatively.

  On the other hand, the CPU 71 starts the valve control routine for the 4-cycle spark ignition operation shown in FIG. 3 from step 300 every time a minute constant crank angle (here, the crank angle is 1 degree = 1 CA). Accordingly, when the predetermined timing is reached, the CPU 71 starts the process from step 300 and proceeds to step 305 to determine whether or not the current absolute crank angle is any one of 150, 390, and 630 degrees (ie, any cylinder). Is 150 degrees after the 4-cycle compression top dead center).

  In this case, if the condition of step 305 is not satisfied, the CPU 71 makes a “No” determination at step 305 to proceed to step 395 to end the present routine tentatively. On the other hand, if the condition of step 305 is satisfied, the CPU 71 determines “Yes” in step 305 and proceeds to step 310 to determine whether or not the value of the flag X4 is “1”. As described above, the value of the flag X4 is set to “1” by the initial routine. Alternatively, the value of the flag X4 is set to “1” in step 245 in the routine of FIG. 2 described later when the engine operating state shifts from the two-cycle self-ignition operation region to the four-cycle spark ignition operation region. . Therefore, the CPU 71 determines “Yes” at step 310 and proceeds to steps 315 to 330 to execute the processing described below.

Step 315: The exhaust valve opening timing EO4 for the 4-cycle spark ignition operation is calculated from MapEO4 (Accp, NE).
Step 320: The exhaust valve closing timing EC4 for the 4-cycle spark ignition operation is calculated from MapEC4 (Accp, NE).
Step 325: The intake valve opening timing IO4 for the 4-cycle spark ignition operation is calculated from MapIO4 (Accp, NE).
Step 330: The intake valve closing timing IC4 for the 4-cycle spark ignition operation is calculated from MapIC4 (Accp, NE).

  The required torque Tqtgt is determined by the accelerator pedal operation amount Accp and the engine rotational speed NE. Therefore, when a certain amount X is obtained from the table MapX (Accp, NE), the certain amount X is determined by the required torque Tqtgt (and the engine rotational speed). NE). This applies similarly throughout this specification.

  Next, the CPU 71 proceeds to step 335 to open the exhaust valve 34 of the cylinder that is 150 degrees after the compression top dead center at the exhaust valve opening timing EO4 and at the exhaust valve closing timing EC4. The timing for sending the output signal to the drive circuit 38 is set so as to cause the output signal to be driven. Furthermore, the CPU 71 opens the intake valve 32 of the cylinder, which is currently 150 degrees after compression top dead center, at the intake valve opening timing IO4 and closes at the intake valve closing timing IC4. The timing for sending the output signal is set to 38. Thereafter, the CPU 71 proceeds to step 395 to end the present routine tentatively. Thereby, the intake valve 32 and the exhaust valve 34 of each cylinder are opened and closed at the valve timing for four-cycle spark ignition.

  Further, the CPU 71 executes the supercharger control routine of FIG. 4 every elapse of a predetermined time. Therefore, when the predetermined timing is reached, the CPU 71 starts processing from step 400 in FIG. 4 and determines in step 405 whether or not the value of the flag X is “1”. As described above, the value of the flag X is set to “0” by the initial routine. Alternatively, the value of the flag X is set to “0” in step 235 in the routine of FIG. 2 described later when the engine operating state shifts from the 2-cycle self-ignition operation region to the 4-cycle spark ignition operation region. .

  Accordingly, the CPU 71 makes a “No” determination at step 405 and proceeds to step 410 to send a drive signal to the supercharger clutch 46a to turn the clutch 46a off and to make the supercharger 46 inactive. At this stage, since the clutch 46a is in an off state, the operation of step 410 is executed in a confirming manner. Thereafter, the CPU 71 proceeds to step 495 to end the present routine tentatively.

  In addition, the CPU 71 executes a fuel injection control routine and an ignition timing control routine for a four-cycle spark ignition operation (not shown), and the air flow rate Ga measured by the air flow meter 61 (or the required torque Tqtgt or accelerator pedal operation) The fuel injection amount tau is determined on the basis of the amount Accp) and the engine rotational speed NE, and the fuel of the fuel injection amount tau is injected from the injector 37 of the cylinder into the cylinder that is in the intake stroke in the four-cycle spark ignition operation system. In addition, the ignition timing θig is determined based on the measured air flow rate Ga (or required torque Tqtgt or accelerator pedal operation amount Accp) and the engine rotational speed NE, and the compression stroke in the four-cycle spark ignition operation system is reached. A spark is generated from the spark plug 35 when the crank angle of the cylinder in question becomes θig. As described above, the operation by the 4-cycle spark ignition operation method is performed.

<Switching from 4-cycle spark ignition operation to 2-cycle self-ignition operation>
Next, as the operation state of the internal combustion engine 10 changes and the operation state shifts from the four-cycle spark ignition operation region to the two-cycle self-ignition operation region, the operation method is changed from the four-cycle spark ignition operation method to the two-cycle self-ignition operation region. The operation of the present control device when switching to the ignition operation method will be described.

  In this case, when the CPU 71 executes the routine shown in FIG. 2 immediately after the operating state of the engine 10 shifts from the four-cycle spark ignition operation region to the two-cycle self-ignition operation region, the CPU 71 executes steps 200 to 210 in FIG. In the subsequent step 215, “Yes” is determined, and the process proceeds to step 225, in which it is determined whether or not the operating state of the engine was within the four-cycle spark ignition operation region when this routine was executed last time. If the above-mentioned assumption is followed, the last driving | running state will be in a 4-cycle spark ignition driving | running | working area | region. Accordingly, the CPU 71 makes a “Yes” determination at step 225 to proceed to step 230, sets the value of the flag X to “1”, and then temporarily ends this routine at step 295.

  At this stage, the value of the flag X4 remains “1”. Therefore, when the absolute crank angle is any one of 150, 390, and 630 degrees (that is, when any cylinder is 150 degrees after the 4-cycle compression top dead center), the CPU 71 performs the 4-cycle spark shown in FIG. Steps 300 to 335 of the ignition operation valve control routine are executed.

  Further, the CPU 71 starts processing from step 400 in FIG. 4 at a predetermined timing. In this case, since the value of the flag X is set to “1”, it is determined as “Yes” in step 405 and the step is executed. Go to 415. In step 415, the CPU 71 determines whether or not the value of the flag X2 has just changed from “0” to “1”.

  At this time, the value of the flag X2 remains “0”. Therefore, the CPU 71 makes a “No” determination at step 415, and after the time when the absolute crank angle reaches 240 degrees for the first time after the value of the flag X2 is changed from “0” to “1” at step 430. It is determined whether or not. Even in this case, the value of the flag X2 is “0” and does not change to “1”. Therefore, the CPU 71 makes a “No” determination at step 430 to proceed to step 495. As a result, the supercharger 46 is maintained in an inoperative state.

  As described above, as indicated by the signs A and B in the time chart of FIG. 5, even after the value of the flag X is changed from “0” to “1”, the value of the flag X4 is “1”. As long as the cylinder that has reached 150 degrees after compression top dead center in the four-cycle spark ignition operation method is operated by the four-cycle spark ignition operation method, the supercharger 46 is maintained in the non-operating state.

  On the other hand, the CPU 71 starts the flag operation routine shown in FIG. 6 from step 600 every time a minute constant crank angle (here, 1 degree = 1 CA) elapses. Therefore, when the predetermined timing is reached, the CPU 71 starts processing from step 600 and proceeds to step 605. The current time point reaches the absolute crank angle of 600 degrees only after the value of the flag X changes from “0” to “1”. It is determined whether or not the timing is correct.

  If the current timing is not the timing when the absolute crank angle reaches 600 degrees for the first time after the value of the flag X changes from “0” to “1”, the CPU 71 determines “No” in step 605 and proceeds to step 610. It is determined whether or not the present time is the timing when the absolute crank angle reaches 0 degrees (= 720 degrees) for the first time after the value of the flag X2 changes from “0” to “1”. In this case, the value of the flag X2 remains “0”. Therefore, the CPU 71 makes a “No” determination at step 610 to proceed directly to step 695 to end the present routine tentatively.

  After that, when a predetermined time elapses, the absolute crank angle reaches the absolute crank angle of 600 degrees only after the value of the flag X changes from “0” to “1”. Accordingly, when the CPU 71 executes the process of step 605 at this time, the CPU 71 determines “Yes” in step 605 and proceeds to step 615 to set the value of the flag X2 to “1”. Then, the CPU 71 makes a “No” determination at step 610 to proceed directly to step 695 to end the present routine tentatively.

  Further, when a predetermined time elapses, it is the timing when the absolute crank angle reaches 0 degree (= 720 degrees) for the first time after the value of the flag X2 changes from “0” to “1”. Accordingly, when the CPU 71 executes the process of step 610 at this time, the CPU 71 determines “Yes” in step 610 and proceeds to step 620 to set the value of the flag X4 to “0”. Then, the CPU 71 proceeds to step 695 to end the present routine tentatively.

  As the value of the flag X4 is changed to “0”, the CPU 71 determines “No” in step 310 of FIG. As a result, the valve timing control according to the 4-cycle spark ignition operation system is stopped.

  On the other hand, the CPU 71 starts the two-cycle self-ignition operation valve control routine shown in FIG. 7 from step 700 every time a minute constant crank angle (here, 1 degree = 1 CA) elapses. Therefore, when the predetermined timing is reached, the CPU 71 starts processing from step 700 and proceeds to step 705 to determine whether or not the current time is 90 ° (90 CA) after the top dead center of any cylinder.

  If the current timing is not 90 degrees after the top dead center of any cylinder, the CPU 71 makes a “No” determination at step 705 to proceed to step 795 to end the present routine tentatively. On the other hand, if the current timing is 90 degrees after the compression top dead center of the first cylinder (absolute crank angle 90 degrees), the CPU 71 determines “Yes” in step 705 and proceeds to step 710 to flag It is determined whether or not the value of X2 is “1”. At this time, if the value of the flag X2 is “0”, the CPU 71 makes a “No” determination at step 710 to proceed to step 795 to end the present routine tentatively.

  On the other hand, if it is assumed that the current value of the flag X2 is the straightness set to “1” in step 615 of FIG. 6 described above, the CPU 71 determines “Yes” in step 710 and performs step Proceeding to 715, it is determined whether or not both the intake valve 32 and the exhaust valve 34 of the cylinder (here, the first cylinder) reaching 90 degrees after compression top dead center are closed.

  At this time, as indicated by the symbol t1 in FIG. 5, both the intake valve 32 and the exhaust valve 34 of the first cylinder are closed. Accordingly, the CPU 71 determines “Yes” at step 715 and proceeds to steps 720 to 740 to execute the processing described below.

Step 720: The exhaust valve opening timing EO for 2-cycle self-ignition operation is calculated from MapEO (Accp, NE).
Step 725: A basic scavenging period θbse for two-cycle self-ignition operation is calculated from Map θbse (Accp, NE).
Step 730: The intake valve opening timing IO for 2-cycle self-ignition operation is calculated from MapIO (Accp, NE).
Step 735: The intake valve closing timing IC for the 2-cycle self-ignition operation is calculated from MapIC (Accp, NE).
Step 740: The exhaust valve closing timing EC for the two-cycle self-ignition operation is set to a timing obtained by adding the basic scavenging period θbse to the intake valve opening timing IO.

  Next, the CPU 71 proceeds to step 745 to open the exhaust valve 34 of the cylinder (in this case, the first cylinder) which is 90 degrees after the top dead center at the exhaust valve opening timing EO and close the exhaust valve. The timing for sending the output signal to the drive circuit 38 is set so that the valve is closed at the valve timing EC. Further, the CPU 71 opens the intake valve 32 of the cylinder, which is 90 degrees after the top dead center, at the intake valve opening timing IO and closes at the intake valve closing timing IC. Set the time to send the output signal to. Thereafter, the CPU 71 proceeds to step 795 to end the present routine tentatively.

  As a result, as indicated by the symbol C in FIG. 5, the timing at which the absolute crank angle reaches 600 degrees for the first time after the value of the flag X changes from “0” to “1” (the value of the flag X2 becomes “1”). After the changed timing), the intake valve 32 and the exhaust valve 34 of the first cylinder that have reached 90 degrees after top dead center are opened and closed at the valve timing for two-cycle self-ignition. As a result, the valve timing of the intake valve 32 and the exhaust valve 34 of the first cylinder is switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method.

  Thereafter, when a predetermined time elapses, the crank angle of the second cylinder becomes 90 degrees after the top dead center (the absolute crank angle is 210 degrees) (see the time point indicated by the symbol t2 in FIG. 5). At this time, when the CPU 71 starts the processing of the routine shown in FIG. 7 from step 700, the CPU 71 determines “Yes” in steps 705 and 710 and proceeds to step 715.

  In this case, as indicated by the symbol B in FIG. 5, the second cylinder is operated by the four-cycle spark ignition operation method, and either the intake valve 32 or the exhaust valve 34 (in this case, the intake valve 32) is opened. I speak. Accordingly, the CPU 71 makes a “No” determination at step 715 to proceed to step 795 to end the present routine tentatively. As a result, the valve timing of the intake valve 32 and the exhaust valve 34 of the second cylinder is maintained at the valve timing of the 4-cycle spark ignition operation system until the timing of 90 degrees comes after the next top dead center. The valve timing is switched to the two-cycle self-ignition method operation timing at a timing of 90 degrees after the dead point.

  Further, after a predetermined time has elapsed, the crank angle of the third cylinder becomes 90 degrees after the top dead center (the absolute crank angle is 330 degrees) (see the time indicated by the symbol t3 in FIG. 5). At this time, when the CPU 71 starts the processing of the routine shown in FIG. 7 from step 700, the CPU 71 determines “Yes” in both step 705 and step 710 and proceeds to step 715.

  In this case, both the intake valve 32 and the exhaust valve 34 of the second cylinder are closed. Therefore, the CPU 71 makes a “Yes” determination at step 715 to execute the above-described processing of step 720 to step 745, proceeds to step 795, and once ends this routine. As a result, the valve timing of the intake valve 32 and the exhaust valve 34 of the third cylinder is switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method.

  Thus, after the timing when the absolute crank angle reaches 600 degrees for the first time after the value of the flag X changes from “0” to “1” (the timing when the value of the flag X2 is changed to “1”), A cylinder that has reached 90 degrees after dead center, and both the intake valve 32 and the exhaust valve 34 are closed, the valve timing of the intake valve 32 and the exhaust valve 34 of the cylinder is a four-cycle spark ignition operation system. Is sequentially switched to the valve timing to the 2-cycle self-ignition method operation method.

  Further, the CPU executes a fuel injection control routine for two-cycle self-ignition operation (not shown), determines the fuel injection amount tau based on the required torque Tqtgt and the engine speed NE, and in the two-cycle self-ignition operation method. The fuel of the fuel injection amount tau is injected from the injector 37 of the cylinder to the cylinder that has reached the scavenging stroke. As described above, as shown by reference characters C, D, and F in FIG. 5, the operation mode of each cylinder is sequentially switched from the 4-cycle spark ignition operation mode to the 2-cycle self-ignition mode operation mode.

  On the other hand, since the crank angle has reached the absolute crank angle of 600 degrees for the first time after the value of the flag X has changed from “0” to “1”, the value of the flag X2 has changed from “0” to “0” in step 615 of FIG. When the CPU 71 starts the supercharger control routine shown in FIG. 4 immediately after the change to “1”, the CPU 71 determines “Yes” in step 405 and step 415 and proceeds to step 420.

  In step 420, the CPU 71 operates the supercharger 46 when the crank angle has passed 220 degrees from the current time, that is, when the crank angle actually becomes 100 degrees (= 600 + 220-720). The setting for sending a drive signal to the supercharger clutch 46a is performed. Next, in step 425, the CPU 71 controls the ABV 45 so that the opening degree SABV of the ABV 45 becomes the ABV opening degree SH. Thereafter, the CPU 71 proceeds to step 495 to end the present routine tentatively.

  As a result, as indicated by the symbol L in FIG. 5, the supercharging pressure starts to increase when the crank angle reaches the absolute crank angle of 100 degrees, and the scavenging stroke of the first cylinder indicated by the symbol C in FIG. By the start time (by the time when the crank angle reaches approximately 120 degrees as an absolute crank angle), a predetermined high supercharging pressure is reached.

  Thereafter, when the CPU 71 starts processing from step 400 in FIG. 4, the CPU 71 determines “Yes” in step 405 and is not immediately after the value of the flag X2 is changed from “0” to “1”. Therefore, “No” is determined in step 415 and the process proceeds to step 430. In step 430, the CPU 71 determines whether or not the current time is after the time when the absolute crank angle reaches 240 degrees for the first time after the value of the flag X2 is changed from “0” to “1”. At this time, if the condition of step 430 is not satisfied, the CPU 71 makes a “No” determination at step 430 to proceed to step 495 to end the present routine tentatively.

  Thereafter, when the time further elapses and the crank angle becomes the absolute crank angle 240 degrees for the first time after the value of the flag X2 is changed from “0” to “1”, the CPU 71 starts processing from step 400 in FIG. Then, the CPU 71 determines “Yes” at step 405, “No” at step 415, and “Yes” at step 430, and proceeds to step 435 to set the ABV opening degree SL to the table MapSL (Tqtgt, NE). Ask for. The ABV opening SL is an opening larger than the ABV opening SH (an opening that increases the amount of bypass air of the supercharger 46). Next, in step 440, the CPU 71 controls the ABV 45 so that the opening degree SABV of the ABV 45 becomes the ABV opening degree SL determined as described above, and proceeds to step 495 to end this routine once.

  Thereafter, unless the value of the flag X is changed from “1” to “0” in step 235 of FIG. 2, which will be described later (that is, unless the engine operating condition returns to the 4-cycle operation region), the CPU 71 Repeats the processing of step 405, step 415, and steps 430-440.

  As a result, the supercharging pressure is determined by the table MapSL (Tqtgt, NE) after the time when the crank angle becomes the absolute crank angle 240 degrees for the first time after the value of the flag X2 is changed from “0” to “1”. Control is performed so that the ABV opening degree SL is obtained.

<Switching from 2-cycle self-ignition operation to 4-cycle spark ignition operation>
Next, as the operation state of the internal combustion engine 10 changes and the operation state shifts from the two-cycle self-ignition operation region to the four-cycle spark ignition operation region, the operation method is changed from the two-cycle self-ignition operation method to the four-cycle spark operation method. The operation of the present control device when switching to the ignition operation system will be described.

  In this case, when the CPU 71 executes the routine shown in FIG. 2 immediately after the operating state of the engine 10 shifts from the two-cycle self-ignition operation region to the four-cycle spark ignition operation region, the CPU 71 proceeds to step 200 to step 210 in FIG. In step 215, “No” is determined, and the process proceeds to step 220. In step 220, “Yes” is determined, and the following processes in steps 235 to 245 are performed.

Step 235: The value of the flag X is set to “0”.
Step 240: The value of the flag X2 is set to “0”.
Step 245: The value of the flag X4 is set to “1”.

  As a result, “Yes” is determined in step 310 in the routine of FIG. 3, so that the intake valve 32 and the exhaust valve 34 are opened and closed at the valve timing for the 4-cycle spark ignition operation. Further, since it is determined as “No” in step 710 in the routine of FIG. 7, the intake valve 32 and the exhaust valve 34 are not opened and closed at the valve timing for the two-cycle self-ignition operation. As described above, the routines shown in FIGS. 3 and 7 control the opening / closing timings of the intake valves and the exhaust valves of the plurality of cylinders based on the torque required for the engine and the determined operation method. It constitutes a valve timing control means.

  In addition, since “No” is determined in Step 405 of FIG. 4, the supercharger 46 is controlled to be inactivated in Step 410.

  As described above, according to the control apparatus for an internal combustion engine according to the first embodiment, the two-cycle self-ignition operation method is started when the cylinder operation method is sequentially switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method. The scavenging stroke (the scavenging stroke of the first cylinder indicated by the symbol C in FIG. 5) of any cylinder that starts the operation by the ignition operation method is another cylinder (FIG. 5) that is operated by the four-cycle spark ignition operation method. In the case of overlapping with the intake stroke of the second cylinder), the supercharging pressure (supercharging pressure corresponding to the ABV opening SABV) is the same as the torque Tqtgt required for the engine at the same time. A pressure (ABV opening) larger than the supercharging pressure (supercharging pressure corresponding to the ABV opening SL in step 435) at the time when the operation by the two-cycle self-ignition operation method is regularly performed. Is controlled to boost pressure) corresponding to the SH.

  As a result, at the time of starting to sequentially switch the cylinder operation method from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method, the cylinder operated by the four-cycle spark ignition operation method and the two-cycle self-ignition operation method are operated. Since a cylinder that is mixed and operated by the four-cycle spark ignition system is in the intake stroke (the intake stroke of the second cylinder indicated by reference B in FIG. 5), the cylinder (second cylinder) The amount of fresh air (and hence the amount of scavenging) in the cylinder (first cylinder) in the scavenging stroke of the two-cycle self-ignition operation system in which fresh air is taken is increased by increasing the supercharging pressure. Therefore, the scavenging amount of the cylinder (first cylinder) in the scavenging stroke at the time of switching between the four cycles and the two cycles is not short (the amount is the same as the scavenging amount in the two-cycle steady operation), and thus the internal combustion engine 10 is generated. Torque fluctuations can be suppressed.

  In other words, since the supercharging pressure is a factor that determines the scavenging amount, the control device according to the first embodiment discharges gas from the cylinder in the scavenging stroke during the scavenging stroke in the two-cycle self-ignition operation method. The amount of scavenging is the amount of the scavenging, and the amount of scavenging at the start of switching the cylinder operation method from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method is requested to the engine at the same time. A factor for determining the scavenging amount so as to approach the scavenging amount at the time when the operation by the two-cycle self-ignition operation method is regularly performed by the valve timing control means under the same torque as the torque being It can also be said that a scavenging amount control means for controlling (a supercharger control routine shown in FIG. 4 and a routine for performing flag operations such as flags X and X2) is provided.

(Second Embodiment)
Next, a control device for an internal combustion engine according to a second embodiment will be described. This control device controls the opening / closing timing (valve timing) of the intake valve 32 and the exhaust valve 34 at the time of switching between 4 cycles and 2 cycles to ensure the scavenging amount equivalent to that at the time of steady operation of 2 cycles (or start of the compression stroke). The combustion gas temperature at the time is set to a gas temperature equivalent to that in the two-cycle steady operation), thereby suppressing fluctuations in torque generated by the internal combustion engine 10. Since the scavenging amount changes when the opening / closing timing of the intake valve 32 and the exhaust valve 34 changes, these (valve timing) are factors that determine the scavenging amount.

<During 4-cycle spark ignition operation>
The CPU 71 of the second embodiment executes the fuel injection control routine and the ignition timing control routine for the four-cycle spark ignition operation (not shown) shown in FIGS. Accordingly, the control device of the second embodiment performs the same control as the control device of the first embodiment with respect to the opening / closing control of the intake valve 32 and the exhaust valve 34, fuel injection control, and ignition timing control, and performs the four-cycle spark ignition operation. Operate according to the method. Further, the CPU 71 maintains the supercharger 46 in the non-operating state during the four-cycle spark ignition operation (flag X = 1) (see step 805 and step 830 in FIG. 8 described later).

<Switching from 4-cycle spark ignition operation to 2-cycle self-ignition operation>
The CPU 71 activates the supercharger 46 when any of the cylinders starts to be operated by the two-cycle self-ignition operation method at the time of switching between four cycles and two cycles. The supercharger 46 is maintained in the operating state while the two-cycle self-ignition operation method is being performed. The supercharging pressure when the supercharger 46 is in the operating state is controlled to a supercharging pressure determined by the required torque Tqtgt and the engine speed NE. Note that the CPU 71 does not increase the supercharging pressure when any of the cylinders starts to be operated by the two-cycle self-ignition operation method as compared with the two-cycle steady operation as in the first embodiment. The same supercharging pressure is used.

  More specifically, the CPU 71 starts processing from step 800 in FIG. 8 instead of FIG. 4 every elapse of a predetermined time. Then, by executing Step 805, Step 815 and Step 820 which are the same as Step 405, Step 415 and Step 420 of FIG. 4, respectively, the value of the flag X is “1” and the value of the flag X2 is “0”. The supercharger 46 is put into an operating state when the crank angle has passed 220 degrees from the time when it has changed from 1 to “1”. Next, in step 825, the CPU 71 determines the ABV opening SABV by MapSABV (Tqtgt, NE).

  Further, as long as the value of the flag X is “1”, step 825 is executed even if the condition of step 815 is not satisfied. Accordingly, the supercharging pressure when operating in the two-cycle self-ignition operation system is a supercharging pressure determined by the required torque Tqtgt and the engine speed NE. When the operating state of the engine 10 is in the 4-cycle spark ignition operation region and the value of the flag X is set to “0”, the CPU 71 determines “No” in step 805 and proceeds to step 830. Proceeding, the supercharger 46 is deactivated.

  Next, opening / closing control of the intake valve 32 and the exhaust valve 34 will be described. The CPU 71 starts the two-cycle self-ignition operation valve control routine shown in the flowchart of FIG. 9 instead of FIG. 7 from step 900 every time a minute constant crank angle (here, the crank angle is 1 degree = 1 CA). ing. Therefore, when the predetermined timing is reached, the CPU 71 starts processing from step 900 and proceeds to step 902 to determine whether or not the current time is 90 ° (90 CA) after the top dead center of any cylinder. If the current timing is not 90 degrees after the top dead center of any cylinder, the CPU 71 makes a “No” determination at step 902 to proceed to step 995 to end the present routine tentatively.

  If the current timing is 90 degrees after the top dead center of any cylinder, the CPU 71 makes a “Yes” determination at step 902 to proceed to step 904, and whether the value of the flag X2 is “1”. Determine whether or not. At this time, if the value of the flag X2 is not “1”, the CPU 71 proceeds to step 995 to end the present routine tentatively.

  Now, for the sake of explanation, the current time is “the value of the flag X is changed from“ 0 ”to“ 0 ”in step 230 of FIG. 2 in accordance with the operation state of the engine 10 shifting from the 4-cycle operation region to the 2-cycle operation region. Immediately after the value of the flag X2 is changed from “0” to “1” in step 615 of FIG. 6 with the change of the crank angle to the absolute crank angle of 600 degrees. In addition, the crank angle of the first cylinder is 90 degrees after the top dead center. The explanation will continue.

  In this case, the CPU 71 determines “Yes” in step 902 following step 900 and proceeds to step 904 to determine whether or not the value of the flag X2 is “1”. According to the above assumption, the value of the flag X2 is “1”. Accordingly, the CPU 71 makes a “Yes” determination at step 904 to proceed to step 906, where both the intake valve 32 and the exhaust valve 34 of the cylinder (in this case, the first cylinder) reaching 90 degrees after the compression top dead center. It is determined whether or not the valve is closed.

  At this time, as indicated by the symbol t1 in FIG. 5, both the intake valve 32 and the exhaust valve 34 of the first cylinder are closed. Accordingly, the CPU 71 determines “Yes” in step 906, proceeds to step 908, step 910, and step 911, and executes the processing described below.

Step 908: The exhaust valve opening timing EO for 2-cycle self-ignition operation is calculated from MapEO (Accp, NE).
Step 910: The basic scavenging period θbse for the 2-cycle self-ignition operation is calculated from Map θbse (Accp, NE).
Step 911: The intake valve opening timing IO for two-cycle self-ignition operation is calculated from MapIO (Accp, NE).

  Next, the CPU 71 proceeds to step 912, and determines whether or not the previous combustion of the cylinder (in this case, the first cylinder) that has reached 90 degrees after top dead center was four-cycle spark ignition combustion. In this case, since the previous combustion of the first cylinder was four-cycle spark ignition combustion, the CPU 71 determines “Yes” in step 912 and sets the combustion gas temperature compensation scavenging extension period θexbse to Mapθexbse (NE , PM). Thereby, as will be described later, the scavenging period is extended by θexbse.

  As described above, if the scavenging period is extended by the combustion gas temperature compensation scavenging extension period θexbse, if the previous combustion is the combustion by the four-cycle spark ignition operation, the combustion gas temperature is the same as that in the two-cycle steady operation by the self-ignition. This is because the temperature is higher than the combustion gas temperature, so that the pre-ignition is prevented from occurring by extending the scavenging period and reducing the amount of remaining combustion gas.

  Next, the CPU 71 proceeds to step 916 to determine whether at least one of the intake valve 32 and the exhaust valve 34 of another cylinder currently operated by the four-cycle spark ignition operation method is open. In this case, the second cylinder is operated by a four-cycle spark ignition operation method, and at least one of the intake valve 32 and the exhaust valve 34 (in this case, the intake valve 32) of the second cylinder is open. . Accordingly, the CPU 71 determines “Yes” in step 916 and proceeds to step 918 to step 924 to perform the following processing. Step 916 is a step of determining whether or not the current state is an intake state or an exhaust state that is different from that in the two-cycle steady operation.

Step 918: The temporary exhaust valve closing timing ECZ for two-cycle self-ignition operation is set to a timing when the basic scavenging period θbse has elapsed from the intake valve opening timing IO.
Step 920: Intake valve opening timing IO, provisional exhaust valve closing timing ECZ, intake valve opening timing IO4 and intake valve closing timing IC4 calculated at that time by the 4-cycle spark ignition valve control routine of FIG. (In this case, IO4 and IC4 correspond to the opening timing and the closing timing of the intake valve 32 of the second cylinder, respectively.) Based on the provisional scavenging period of the first cylinder (the period of the scavenging stroke, that is, , IO to ECZ) and the second cylinder's intake period (the period of the intake stroke, that is, the period of IO4 to IC4) is obtained.

  Step 922: The interference compensation scavenging extension period θexkan is determined by Mapθexkan (θkan, PM). As will be described later, the basic scavenging period is extended by the interference compensation scavenging extension period θexkan. When the cylinder that starts the two-cycle self-ignition operation enters the scavenging stroke, if the other cylinder enters the intake stroke of the four-cycle spark ignition operation, the cylinder that starts the two-cycle self-ignition operation enters the intake stroke. The new cylinder is deprived of freshness. As a result, the amount of fresh air drawn into the cylinder that starts the two-cycle self-ignition operation decreases, and the scavenging amount of the cylinder becomes insufficient. The interference compensation scavenging extension period θexkan is a period for extending the basic scavenging period θbse in order to compensate for the shortage of the scavenging amount due to such a reason.

When only the exhaust valve 34 of the cylinder that starts the 2-cycle self-ignition operation is open (when the cylinder is in the exhaust stroke), the other cylinders are in the exhaust stroke of the 4-cycle spark ignition operation. In addition, since the exhaust pressure is high, the scavenging amount of the cylinder that starts the two-cycle self-ignition operation may be insufficient. Accordingly, the interference compensation scavenging extension period θexkan is obtained from the exhaust valve opening timing EO, the intake valve opening timing IO, the temporary exhaust valve closing timing ECZ, MapIC (Accp, NE), and the like. Based on the intake valve closing timing IC, the intake valve opening timing IO4, the intake valve closing timing IC4, the exhaust valve opening timing EO4, and the exhaust valve closing timing EC4, the two-cycle self-ignition operation is started. It may be determined by considering the scavenging amount or fresh air amount of the cylinder.
Step 924: A scavenging shortening period θshort described later is set to “0”.

Next, the CPU 71 proceeds to step 926 to step 930 and performs the following processing.
Step 926: The basic scavenging period θbse is extended by a period obtained by adding the combustion gas temperature compensation scavenging extension period θexbse and the interference compensation scavenging extension period θexkan, and the extended period is shortened by the scavenging reduction period θshort. Set as the final scavenging period θsoki. However, in this case, since the scavenging shortening period θshort is set to “0”, the scavenging period is not shortened.

Step 928: The final exhaust valve closing timing EC is set to a timing when the scavenging period θsoki has elapsed from the intake valve opening timing IO.
Step 930: The final intake valve closing timing IC is set to a timing after a certain period θconst has elapsed from the exhaust valve closing timing EC.

  Thereafter, in step 932, the CPU 71 opens the exhaust valve 34 of the cylinder (in this case, the first cylinder) which is 90 degrees after the top dead center at the exhaust valve opening timing EO and closes the exhaust valve. The timing for sending the output signal to the drive circuit 38 is set so that the valve is closed at the valve timing EC. At the same time, the CPU 71 opens the intake valve 32 of the cylinder, which is 90 degrees after the top dead center, at the intake valve opening timing IO and closes at the intake valve closing timing IC. The timing for sending the output signal is set to 38. Next, the CPU 71 proceeds to step 995 to end the present routine tentatively.

  As described above, the scavenging period θsoki of the first cylinder in which the operation method is switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method prior to the other cylinders is the basic scavenging that is the scavenging period in the two-cycle steady operation. This is a period extended by at least the interference compensation scavenging extension period θexkan from the period θbse. As a result, a scavenging amount of the cylinder (first cylinder) that overlaps the intake stroke of the other cylinder (second cylinder) that is operated by the four-cycle spark ignition operation method during the operation switching is sufficiently ensured. Further, the scavenging period θsoki of the first cylinder is extended by an amount corresponding to the combustion gas temperature being higher than the combustion gas temperature during the two-cycle steady operation. As a result, the scavenging amount of the first cylinder becomes appropriate (that is, the combustion gas of an appropriate amount and at an appropriate temperature remains in the first cylinder), so that the self-ignition combustion of the first cylinder is in a two-cycle steady operation. Done like time. Thereby, the fluctuation | variation of the torque which generate | occur | produces at the time of 4 cycle-2 cycle switching is suppressed.

  Thereafter, when a predetermined time elapses, the crank angle of the second cylinder becomes 90 degrees after the top dead center (the absolute crank angle is 210 degrees) (see the time point indicated by the symbol t2 in FIG. 5). At this time, when the CPU 71 starts the processing of the routine shown in FIG. 9 from step 900, the CPU 71 determines “Yes” in both steps 902 and 904, and proceeds to step 906.

  In this case, the second cylinder is operated by a four-cycle spark ignition operation method, and either the intake valve 32 or the exhaust valve 34 (in this case, the intake valve 32) is opened. Therefore, the CPU 71 makes a “No” determination at step 906 to proceed to step 995 to end the present routine tentatively. As a result, the valve timing of the intake valve 32 and the exhaust valve 34 of the second cylinder is maintained at the valve timing of the 4-cycle spark ignition operation system until the timing of 90 degrees comes after the next top dead center. The valve timing is switched to the two-cycle self-ignition method operation timing at a timing of 90 degrees after the dead point.

  Further, after a predetermined time has elapsed, the crank angle of the third cylinder becomes 90 degrees after the top dead center (the absolute crank angle is 330 degrees) (see the time indicated by the symbol t3 in FIG. 5). At this time, when the CPU 71 starts the processing of the routine shown in FIG. 9 from step 900, the CPU 71 determines “Yes” in both steps 902 and 904, and proceeds to step 906.

  In this case, both the intake valve 32 and the exhaust valve 34 of the third cylinder are closed. Accordingly, the CPU 71 determines “Yes” in step 906 and performs the processing of steps 908 to 911 described above. Next, the CPU 71 proceeds to step 912 to determine whether or not the previous combustion of the cylinder (in this case, the third cylinder) that has reached 90 degrees after top dead center was four-cycle spark ignition combustion. Since the previous combustion of the third cylinder was four-cycle spark ignition combustion, the CPU 71 determines “Yes” in step 912, and sets the combustion gas temperature compensation scavenging extension period θexbse to Mapθexbse (NE, PM) in step 914. Determine based on. Thereby, as will be described later, the scavenging period is extended by θexbse.

  Next, the CPU 71 proceeds to step 916. At this time, the second cylinder is operated by the four-cycle spark ignition operation method. However, both the intake valve 32 and the exhaust valve 34 of the second cylinder are closed. Accordingly, the CPU 71 makes a “No” determination at step 916 to proceed to step 934, where the current time or immediately before (or at the same time as or immediately before the exhaust valve opening timing EO or the intake valve opening timing IO, in other words, top dead. It is determined whether or not there is a scavenging stroke of another cylinder during the scavenging stroke of the cylinder that reaches 90 degrees after the point and immediately before the scavenging stroke.

  As understood from FIG. 5, during the two-cycle steady operation, the time interval between the scavenging stroke of one cylinder and the scavenging stroke of another cylinder is extremely short. On the other hand, as indicated by reference symbols D and B in FIG. 5, the scavenging strokes of the other cylinders exist immediately before the third cylinder is about to start the operation by the two-cycle self-ignition operation method. No (in this case, after the intake stroke in the 4-cycle spark ignition operation mode). Accordingly, since the exhaust gas discharged from the engine 10 has already flowed downstream, the exhaust pressure is smaller than that during the two-cycle steady operation. That is, the step 934 is a step of determining whether or not the exhaust pressure is different from that during the two-cycle steady operation (exhaust state).

  At this time, the determination condition of step 934 is satisfied. Therefore, the CPU 71 determines “Yes” in step 934 and proceeds to step 936 to step 940 to perform the following processing.

Step 936: Exhaust valve opening timing EO and the exhaust valve closing timing EC4 calculated at that time by the 4-cycle spark ignition valve control routine of FIG. 3 (in this case, EC4 is the closing of the exhaust valve 34 of the second cylinder) Based on the valve timing, the valve opening non-period θnashi (that is, the length of the period from EC4 to EO), which is a period in which none of the exhaust valves is opened, is obtained. The no-open period θnashi is a period from the exhaust valve closing timing EC4 to the intake valve opening timing IO, a period from the intake valve closing timing IC4 to the exhaust valve opening timing EO, or the intake valve closing timing. It is good also as a period from IC4 to intake valve opening timing IO.
Step 938: The scavenging shortening period θshort is calculated from Mapθshort (θnashi, PM).
Step 940: The interference compensation scavenging extension period θexkan is set to “0”.

  Thereafter, the CPU 71 executes processes of steps 926 to 932. Accordingly, the final scavenging period θsoki is a period in which the basic scavenging period θbse is extended by the combustion gas temperature compensation scavenging extension period θexbse and the extended period is shortened by the scavenging reduction period θshort.

  As described above, the operation mode of the third cylinder is switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method following the first cylinder and earlier than the second cylinder. At this time, the scavenging period θsoki is set at the time of two-cycle steady operation so that the scavenging amount of the third cylinder does not become excessive due to the exhaust pressure immediately before the scavenging stroke being smaller than that at the time of two-cycle steady operation. The basic scavenging period θbse, which is the scavenging period, is shortened by at least the scavenging shortening period θshort. In addition, the basic scavenging period θbse is extended by the combustion gas temperature compensation scavenging extension period θexbse because the combustion gas temperature remaining in the cylinder is higher than that in the two-cycle steady operation, thereby making the combustion gas amount appropriate. Is achieved. As a result, the scavenging amount of the third cylinder becomes appropriate (that is, the combustion gas of an appropriate amount and at an appropriate temperature remains in the third cylinder), so that the auto-ignition combustion of the third cylinder performs the two-cycle steady operation. Done like time. Thereby, the fluctuation | variation of the torque which generate | occur | produces at the time of 4 cycle-2 cycle switching is suppressed.

  Further, when a predetermined time elapses, the crank angle of the first cylinder becomes 90 degrees after the top dead center (the absolute crank angle is 450 degrees) (see the time point indicated by the symbol t4 in FIG. 5). At this time, when the CPU 71 starts the processing of the routine shown in FIG. 9 from step 900, the CPU 71 determines “Yes” in both steps 902 and 904, and proceeds to step 906.

  In this case, both the intake valve 32 and the exhaust valve 34 of the first cylinder are closed. Accordingly, the CPU 71 determines “Yes” in step 906 and performs the processing of steps 908 to 911 described above. In this case, since the previous combustion of the first cylinder was two-cycle self-ignition combustion, the CPU 71 determines “No” in step 912, and sets the combustion gas temperature compensation scavenging extension period θexbse to “ Set to “0”.

  Next, the CPU 71 proceeds to step 916. In this case, there is no cylinder that is operated by the four-cycle spark ignition operation method and in which at least one of the intake valve 32 and the exhaust valve 34 is open. Accordingly, the CPU 71 makes a “No” determination at step 916 to proceed to step 934.

  Further, in this case, since the scavenging stroke of the third cylinder exists at the same time as or immediately before the current time, the CPU 71 determines “No” in step 934 and proceeds to step 942, where the scavenging extension period θexkan for interference compensation and The scavenging shortening period θshort is set to “0”. Thereafter, the CPU 71 executes processes of steps 926 to 932. As a result, the final scavenging period θsoki becomes the basic scavenging period θbse, which is the scavenging period during the two-cycle steady operation.

  Further, when the predetermined time has elapsed, the crank angle of the second cylinder becomes 90 degrees after the top dead center (the absolute crank angle is 570 degrees) (see the time indicated by the symbol t5 in FIG. 5). In this case, as can be understood from FIG. 5, the intake valve 32 and the exhaust valve 34 of the second cylinder are both closed, and the cylinder is at 90 degrees after top dead center (in this case, the second cylinder). The previous combustion is a 4-cycle spark ignition combustion. In addition, the condition that at least one of the intake valve 32 and the exhaust valve 34 of the other cylinders operated by the four-cycle spark ignition operation method is currently open is not satisfied.

  Accordingly, the CPU 71 performs the processing of step 902 to step 916, step 934, and step 942, and then executes the processing of step 926 to step 932. As a result, since the interference compensation scavenging extension period θexkan and scavenging shortening period θshort are both set to “0” in step 942, the final scavenging period θsoki uses the basic scavenging period θbse as the combustion gas temperature compensation. This is a period extended by the scavenging extension period θexbse.

  Thus, the operation mode of the second cylinder is switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method following the first and third cylinders. At this time, the final scavenging period θsoki of the third cylinder is a period obtained by extending the basic scavenging period θbse by the combustion gas temperature compensation scavenging extension period θexbse, considering that the combustion gas temperature is higher than that in the two-cycle steady operation. It becomes. As a result, the scavenging amount of the second cylinder becomes appropriate (that is, the combustion gas having the appropriate amount and the appropriate temperature remains in the second cylinder), so that the self-ignition combustion of the second cylinder is in a two-cycle steady operation. Done like time. Thereby, the fluctuation | variation of the torque which generate | occur | produces at the time of 4 cycle-2 cycle switching is suppressed.

  Thereafter, all the cylinders are operated by the two-cycle self-ignition operation method until the value of the flag X2 is set to “0”.

  Thus, the control device for an internal combustion engine according to the second embodiment includes scavenging amount control means for changing the opening / closing timings of the intake valves and the exhaust valves of the plurality of cylinders as a factor for determining the scavenging amount. Actually, the two-cycle valve control routine shown in FIG. 9 constitutes a valve timing control means and a scavenging amount control means.

  Further, in the control device for the internal combustion engine, the scavenging amount control means corresponds to the steps executed in accordance with step 916, step 934 of FIG. 9 and the affirmative determination in these steps, and the operation method is the four-cycle spark ignition. The intake valves and / or exhausts of other cylinders during and immediately before the scavenging stroke of an arbitrary cylinder that starts operation by the two-cycle self-igniting operation method at the time when switching from the operation method to the two-cycle self-ignition operation method is started. The opening / closing timing of the intake valve and the exhaust valve of the same cylinder is changed according to the open / close state of the valve (that is, the intake state and / or the exhaust state).

  Further, the scavenging amount control means corresponds to step 916 to step 920 and step 926 to step 932 in FIG. 9, and the cylinder operation method is changed from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method. When the scavenging stroke of an arbitrary cylinder that starts operation by the same two-cycle self-ignition operation method at the start of switching overlaps with the intake stroke or exhaust stroke of another cylinder that is operated by the same four-cycle spark ignition operation method, the scavenging At the time when the operation of the two-cycle self-ignition operation method is regularly performed by the valve timing control means under the same torque as that required for the engine at the same time during the stroke period Valve timing is controlled to be a period obtained by adding a predetermined extension period (θexkan) to the scavenging stroke period (θbse) That.

  Further, the scavenging amount control means corresponds to step 912, step 914, and step 926 to step 932 in FIG. 9, and the cylinder operation system is changed from the 4-cycle spark ignition operation system to the 2-cycle self-ignition operation system. When the combustion of another cylinder that occurs immediately before the combustion of an arbitrary cylinder that starts operation by the two-cycle self-ignition operation method at the start of switching is combustion by the four-cycle spark point operation method, the period of the scavenging stroke However, at the same time, the scavenging stroke at the time when the valve timing control means is constantly operating by the valve timing control means under the same torque as the torque required for the engine. The valve timing is controlled so as to be a period obtained by subtracting a predetermined shortening period (θshort) from the period (θbse).

  In the above embodiment, the scavenging period is extended by delaying the exhaust valve closing timing EC. However, the scavenging period may be extended by advancing the exhaust valve opening timing EO. Further, the scavenging amount may be changed by changing the exhaust valve closing timing EC, the exhaust valve opening timing EO, and the intake valve opening timing IO (intake and exhaust valve opening / closing timing).

(Third embodiment)
Next, a control device for an internal combustion engine according to a third embodiment will be described. As in the second embodiment, this control device controls the opening / closing timing (valve timing) of the intake valve 32 and the exhaust valve 34 when switching between four cycles and two cycles, thereby obtaining a scavenging amount equivalent to that during two-cycle steady operation. Secure. Further, the control device of the third embodiment prevents the interference between the valve opening period of the exhaust valve 34 of a certain cylinder and the valve opening period of the exhaust valve 34 of another cylinder by controlling valve timing (interference). This is to control the opening and closing timing of the exhaust valve 34.

  When the exhaust valve opening periods overlap in this way, it becomes difficult to exhaust the combustion gas from each cylinder, which causes problems such as a lack of scavenging amount. In the present embodiment, the scavenging amount of the remaining cylinders is secured by changing the opening / closing timing of the exhaust valve 34 of one cylinder so that such a situation does not occur.

  More specifically, the CPU 71 of the third embodiment executes the routine shown in FIG. 10 in addition to the routine executed by the CPU 71 of the second embodiment. The routine shown in FIG. 10 is executed following step 932 of the routine shown in FIG.

  That is, the CPU 71 proceeds to step 1005 after determining the opening / closing timing of the intake valve 32 and the exhaust valve 34 so that the scavenging amount equivalent to that in the 2-cycle steady operation is secured at the time of switching between the 4-cycle and the 2-cycle. A cylinder that performs two-cycle self-ignition combustion immediately before two-cycle self-ignition combustion of a cylinder that is 90 degrees after dead center (hereinafter referred to as “main cylinder”) (hereinafter referred to as “immediate cylinder”). .)) Is determined whether the exhaust valve closing timing ECprior is before the exhaust valve opening timing EO90 of the main cylinder. Here, the exhaust valve closing timing ECprior and the exhaust valve opening timing EO90 are timings in which the exhaust valve closing timing EC of the immediately preceding cylinder and the exhaust valve opening timing EO of the main cylinder are respectively expressed by absolute crank angles.

  Then, when the condition of Step 1005 is established, the CPU 71 determines “Yes” in Step 1005 and proceeds to Step 1015. On the other hand, when the condition of step 1005 is not satisfied, the CPU 71 makes a “No” determination at step 1005 to proceed to step 1010, where the exhaust valve opening timing EO of this cylinder is the exhaust valve closing timing of the immediately preceding cylinder. The setting is made to be ECprior, and the process proceeds to step 1015.

  Next, in step 1015, the CPU 71 calls the cylinder in which the exhaust valve closing timing EC90 of the main cylinder performs the two-cycle self-ignition combustion immediately after the two-cycle self-ignition combustion of the main cylinder (hereinafter referred to as “immediate cylinder”). .)) Is determined whether or not the exhaust valve opening timing EOnext. Here, the exhaust valve closing timing EC90 and the exhaust valve opening timing EOnext are the absolute values of the exhaust valve closing timing EC of this cylinder and the exhaust valve opening timing EO (= MapEO (Accp, NE)) of the immediately following cylinder, respectively. This is the time represented by the crank angle.

  Then, when the condition of step 1015 is established, the CPU 71 determines “Yes” in step 1015 and proceeds to step 1025. On the other hand, when the condition of step 1015 is not satisfied, the CPU 71 makes a “No” determination at step 1015 to proceed to step 1020, where the exhaust valve closing timing EC of the cylinder immediately after the exhaust valve closing timing EC of the main cylinder is determined. The setting is made to be EOnext, and the process proceeds to Step 1025.

  Next, the CPU 71 recalculates the intake valve closing timing IC in step 1025 as in step 930, and the intake valve 32 of this cylinder is closed at the intake valve closing timing IC recalculated in step 1030. Then, the routine shown in FIGS. 9 and 10 is temporarily terminated via step 995 in FIG.

  Thus, as shown in FIG. 11, the post-extended exhaust valve opening period corresponding to the post-extended scavenging period of the cylinder extended by the routine shown in FIG. 9 is the post-corrected exhaust valve corresponding to the post-corrected scavenging period. The valve closing period. Therefore, the exhaust valve opening period of this cylinder does not overlap with the exhaust valve opening periods of the immediately preceding cylinder and the immediately following cylinder, so that at least the scavenging amount of the immediately preceding cylinder and the immediately following cylinder is ensured. If such a process is not performed, three consecutive autoignition combustions may become unstable. On the other hand, in the third embodiment, the combustion in at least the immediately preceding cylinder and the immediately following cylinder is extremely stable, so that torque fluctuation at the time of switching between 4 cycles and 2 cycles can be reduced.

  Thus, the control device of the present embodiment includes scavenging amount control means corresponding to the routine shown in FIG. In this scavenging amount control means, the exhaust valve opening timing of the cylinder that performs combustion after the two cylinders that continuously perform combustion by the two-cycle self-ignition operation method is the first of the two cylinders that performs combustion. It can also be said that the exhaust valve opening timing of the cylinder that performs combustion later is changed so as to arrive later than the exhaust valve closing timing of the cylinder to be performed.

  Further, the scavenging amount control means is configured so that the exhaust valve opening timing of the cylinder that performs combustion after the two cylinders that continuously perform combustion by the two-cycle self-ignition operation method is the first of the two cylinders. It can also be said that the exhaust valve closing timing of the cylinder that performs combustion earlier is changed so that it comes later than the exhaust valve closing timing of the cylinder that performs combustion.

  In the above embodiment, the intake valve opening timing IO of this cylinder is not corrected, but the time after a predetermined angle from the corrected exhaust valve opening timing EC is reset as the intake valve opening timing IO. You may comprise.

(Fourth embodiment)
Next, an internal combustion engine control apparatus according to a fourth embodiment will be described. As in the second embodiment, this control device secures a scavenging amount equivalent to that in the two-cycle steady operation by controlling the opening and closing timings of the intake valve 32 and the exhaust valve 34 when switching between four cycles and two cycles. Furthermore, as shown in FIG. 12A and FIG. 12B, the control device of the fourth embodiment is used when the scavenging period is extended (when the exhaust valve closing timing EC is retarded). ) To control (retard) the fuel injection timing to prevent the injected fuel from being discharged out of the cylinder through the exhaust valve 34 (the fuel is blown through).

  More specifically, the CPU 71 replaces the fuel injection control routine (not shown) executed by the CPU 71 of the second embodiment with a minute constant crank angle (here, 1 degree = 1CA) starts from step 1300 every time.

  Therefore, when the predetermined timing is reached, the CPU 71 starts processing from step 1300 and proceeds to step 1305 to determine whether or not the current time is 100 degrees (100 CA) after the top dead center of any cylinder. If the current timing is not 100 degrees after the top dead center of any cylinder, the CPU 71 makes a “No” determination at step 1305 to proceed to step 1395 to end the present routine tentatively.

  On the other hand, assuming that the current time is 100 degrees after the top dead center of any cylinder, the CPU 71 determines “Yes” in step 1305, and the cylinder that has reached 100 degrees after top dead center in step 1307. It is determined whether or not the cylinder is operated by the two-cycle self-ignition operation method. Step 1307 is a step for determining whether or not the conditions of steps 904 and 906 in FIG. If the condition of step 1307 is not satisfied, the CPU 71 makes a “No” determination at step 1307 to proceed to step 1395 to end the present routine tentatively.

  On the other hand, if the cylinder that has reached 100 degrees after the top dead center is a cylinder that is operated in the two-cycle self-ignition operation system, the CPU 71 determines “Yes” in step 1307 and proceeds to steps 1310 to 1335, Perform the process.

Step 1310: The basic fuel injection timing θinjbse is obtained from the table Mapθinjbse (Accp, NE).
Step 1315: The fuel injection amount tau is obtained from the table Maptau (Accp, NE).
Step 1320: The scavenging extension period Δθsoki is obtained by subtracting the basic scavenging period θbse from the scavenging period θsoki. That is, Δθsoki = θsoki−θbse = θexbse + θexkan−θshort.

  Step 1325: The fuel injection timing correction amount Δθinj is obtained from the table MapΔθinj (Δθsoki, PM). This table Map Δθinj (Δθsoki, PM) indicates that a positive fuel injection timing correction amount Δθinj is obtained when the scavenging extension period Δθsoki is a positive value, and a negative fuel injection when the scavenging extension period Δθsoki is a negative value. The timing correction amount Δθinj is defined to be obtained. Further, the absolute value of the fuel injection timing correction amount Δθinj is determined so as to increase as the absolute value of the scavenging extension period Δθsoki increases, according to the table Map Δθinj (Δθsoki, PM). If the fuel injection timing correction amount Δθinj is a positive value, the fuel injection start timing is retarded, and if the fuel injection timing correction amount Δθinj is a negative value, the fuel injection start timing is advanced.

  The table MapΔθinj (Δθsoki, PM) uses the intake pipe pressure PM as a variable. The larger the intake pipe pressure PM, the faster the scavenging flow, so the fuel is injected faster by the time corresponding to the scavenging flow speed. Otherwise, the fuel may blow through. In other words, the map Δθinj (Δθsoki, PM) determines the fuel injection timing correction amount Δθinj to increase as the intake pipe pressure PM increases.

Step 1330: The final fuel injection timing θinj is set to a timing delayed by the fuel injection timing correction amount Δθinj from the basic fuel injection timing θinjbse.
Step 1335: The injector 37 is opened only during the period of the fuel injection amount tau from the time when the crank angle of the cylinder which is 100 degrees after the top dead center reaches the final fuel injection timing θinj, and the fuel with the fuel injection amount tau Set to inject. This step constitutes basic fuel injection timing determining means for determining the basic fuel injection start timing based on the required torque of the engine and the engine speed.
Thereafter, the CPU 71 proceeds to step 1395 to end the present routine tentatively.

  As described above, in the control device of the fourth embodiment, at the time of switching between 4 cycles and 2 cycles, when the opening timing of the exhaust valve is retarded in order to extend the scavenging period (see step 928 in FIG. 9). .), The fuel injection timing is retarded by an amount Δθinj corresponding to the degree of retardation Δθsoki. Thereby, the amount of fuel (fuel blow-through amount) in which the fuel injected from the injector 37 flows out to the exhaust port 33 as it is can be reduced.

The control device according to the present embodiment is
A fuel injection amount is determined based on the torque required for the engine and the determined operation method, and the determined fuel injection amount of fuel is determined as a required torque of the engine for a cylinder that reaches the combustion stroke. Fuel injection control means for injecting from the basic fuel injection start timing determined based on the engine rotational speed (the fuel injection means including the injector 37, and steps 1310, 1315 and 1335 in FIG. 13);
When the opening / closing timing of the exhaust valve of an arbitrary cylinder that starts operation by the two-cycle self-ignition operation method is controlled by the scavenging amount control means, the fuel injection control means according to the controlled opening / closing timing of the exhaust valve It can also be said that there is provided an injection timing control means (step 1320 to step 1330 in FIG. 13) for changing the injection start timing of the fuel injected from.

(Fifth embodiment)
Next, a control device for an internal combustion engine according to a fifth embodiment will be described. This control device controls the fuel injection amount at the time of switching between 4 cycles and 2 cycles, thereby quickly bringing the combustion gas temperature close to (substantially coincides with) the combustion gas temperature during the 2-cycle steady operation, thereby suppressing torque fluctuations. To do.

  Hereinafter, the operation of the fifth embodiment will be specifically described with reference to FIG. 14 which is a time chart. In FIG. 14, time t100 indicates a point in time immediately before a certain cylinder is switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method. 14A and 14B show changes in the combustion gas temperature, the in-cylinder gas temperature, and the fuel injection amount when no measures are taken with respect to the fuel injection amount. ) And (D) show changes in the combustion gas temperature, the in-cylinder gas temperature and the fuel injection amount in the fifth embodiment. In the example shown in FIG. 14, the required torque Tqtgt = Map (Accp, NE) and the engine speed NE are constant.

  Now, as shown in FIG. 14B, a case where the fuel injection amount after time t100 is the same as the fuel injection amount in the two-cycle steady operation will be considered. In this case, the combustion at time t100 is the combustion by the spark ignition operation. Accordingly, since the combustion gas temperature at time t100 is higher than the combustion gas temperature during the two-cycle steady operation, the in-cylinder gas temperature before compression of the first two-cycle self-ignition combustion immediately after switching between four cycles and two cycles becomes relatively high. . As a result, the combustion gas temperature obtained by the self-ignition combustion also becomes higher than the combustion gas temperature during the two-cycle steady operation. For this reason, the combustion gas temperature obtained by the next self-ignition combustion is also higher than the combustion gas temperature during the two-cycle steady operation. Such a state in which the combustion gas temperature is higher than the combustion gas temperature during the two-cycle steady operation extends to several cycles immediately after switching from 4 cycles to 2 cycles. Accordingly, during this time, the self-ignition combustion becomes unstable, or the self-ignition start timing becomes too early, so that torque fluctuations generated by the engine occur.

  On the other hand, as shown in FIG. 14D, the control device of the present embodiment is configured so that the amount of fuel used for the first two-cycle self-ignition combustion immediately after the 4-cycle-2 cycle switching (fuel injection amount). ) Is reduced compared to the two-cycle steady operation. As a result, as shown in FIG. 14C, the calorific value in the self-ignition combustion is reduced, so that the combustion gas temperature obtained by the self-ignition combustion substantially matches the combustion gas temperature in the two-cycle steady operation. . Therefore, since the in-cylinder gas temperature in the next cycle becomes equal to the in-cylinder gas temperature in the two-cycle steady operation, self-ignition combustion equivalent to that in the two-cycle steady operation is performed from that cycle. As a result, torque fluctuations generated by the engine are suppressed.

  Next, a specific operation of the control device of the fifth embodiment will be described. The CPU 71 of this control device executes a routine (except for the routine shown in FIG. 9) executed by the CPU 71 of the second embodiment, and performs the two-cycle control routine shown in FIG. The process starts from step 1500 every time an angle (here, crank angle 1 degree = 1 CA) has elapsed. Accordingly, when the predetermined timing is reached, the CPU 71 starts processing from step 1500 and proceeds to step 1505 to determine whether or not the current time is 90 ° (90 CA) after the top dead center of any cylinder. If the current timing is not 90 degrees after the top dead center of any cylinder, the CPU 71 makes a “No” determination at step 1505 to proceed to step 1595 to end the present routine tentatively.

  On the other hand, if any cylinder is 90 degrees after top dead center, the CPU 71 determines “Yes” in step 1505 and proceeds to step 1510 to reach 90 degrees after top dead center. It is determined whether or not the cylinder is a cylinder operated by a two-cycle self-ignition operation method. Step 1510 is a step of determining whether or not the conditions of steps 904 and 906 in FIG. When the condition of step 1510 is not satisfied, the CPU 71 makes a “No” determination at step 1510 to proceed to step 1595 to end the present routine tentatively.

  On the other hand, when the condition of step 1510 is established, the CPU 71 determines “Yes” in step 1510 and performs the following processes of steps 1515 to 1540.

Step 1515: The exhaust valve opening timing EO is obtained from the table MapEO (Accp, NE).
Step 1520: The exhaust valve closing timing EC is obtained from the table MapEC (Accp, NE).
Step 1525: The intake valve opening timing IO is obtained from the table MapIO (Accp, NE).
Step 1530: The intake valve closing timing IC is obtained from the table MapIC (Accp, NE).
Step 1535: The fuel injection timing (fuel injection start timing) θinj is obtained from the table Mapθinj (Accp, NE).
Step 1540: The basic fuel injection amount taubse is obtained from the table Maptaubse (Accp, NE).

  Next, the CPU 71 proceeds to step 1545 to determine whether or not the previous combustion of the cylinder at 90 degrees after the top dead center was four-cycle spark ignition combustion. In this case, if the previous combustion is four-cycle spark ignition combustion, the CPU 71 determines “Yes” in step 1545 and proceeds to step 1550 to obtain the fuel injection reduction amount tausub from the table Maptausub (NE, PM). . The reason why the engine speed NE and the intake pipe pressure PM are variables is that they have a great influence on the combustion gas temperature (the combustion gas temperature changes as they change).

Next, the CPU 71 performs the following processing from step 1560 to step 1570, proceeds to step 1595, and once ends this routine.
Step 1560: The final fuel injection amount tau is obtained by subtracting the fuel injection reduction amount tausub from the basic fuel injection amount taubse.
Step 1565: The injector 37 is opened for the period of the fuel injection amount tau from the time when the crank angle of the cylinder which is 90 degrees after the top dead center becomes the fuel injection timing θinj, and the fuel of the fuel injection amount tau is injected. Set as follows.

  Step 1570: The drive circuit 38 is made to open the exhaust valve 34 of the cylinder which is 90 degrees after the top dead center at the exhaust valve opening timing EO and at the exhaust valve closing timing EC. Set the timing to send the output signal. At the same time, an output to the drive circuit 38 is made so that the intake valve 32 of the cylinder which is 90 degrees after the top dead center is opened at the intake valve opening timing IO and closed at the intake valve closing timing IC. Set when to send the signal.

  As described above, the amount of fuel used for the first self-ignition combustion switched from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method does not change the required torque Tqtgt and the rotational speed NE at the time of the operation method switching. Assuming that, the fuel injection amount (basic fuel injection amount) taubse during the two-cycle steady operation is smaller by a predetermined fuel injection reduction amount tausub. Therefore, since the temperature of the combustion gas generated by the self-ignition combustion substantially matches the combustion gas temperature during the two-cycle steady operation, the torque fluctuation of the engine does not occur.

  When the CPU 71 proceeds to step 1545 by executing this routine, the previous combustion of the cylinder that has reached 90 degrees after the top dead center is not four-cycle spark ignition combustion (if it is two-cycle self-ignition combustion). The CPU 71 makes a “No” determination at step 1545 to proceed to step 1555 to set the value of the fuel injection reduction amount tausub to “0”. As a result, the fuel is injected without being reduced after the second cycle after switching to the two-cycle self-ignition operation method.

  In the above embodiment, the amount of fuel used for the first self-ignition combustion switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method is reduced, but the first fuel injection is stopped. (It may be a fuel cut).

  As described above, in the control device of the present embodiment, the fuel injection amount for the cylinder at the time when the operation mode of the cylinder starts to be switched from the 4-cycle spark ignition operation mode to the 2-cycle self-ignition operation mode is the same point. The amount of fuel injection at the time when the valve timing control means and the fuel injection control means are steadily operated by the two-cycle self-ignition operation method under the same torque required for the engine. There is provided a switching fuel injection amount control means (step 1545, step 1550, step 1560 in FIG. 15) for changing the fuel injection amount for the cylinder so that the fuel injection amount is smaller by a predetermined amount (tausub) than (taubse). I can say that.

(Sixth embodiment)
Next, a control device for an internal combustion engine according to a sixth embodiment will be described. The control device of the second embodiment described above changes the scavenging period by changing the opening and closing timings of the intake valve 32 and the exhaust valve 34 at the time of switching between 4 cycles and 2 cycles. The amount was secured, and the fluctuation of the torque generated by the internal combustion engine 10 was suppressed. On the other hand, the control device of the sixth embodiment controls the fuel injection amount instead of controlling the scavenging period, thereby quickly bringing the combustion gas temperature close to the combustion gas temperature during the two-cycle steady operation. It suppresses fluctuations.

  Specifically, the CPU 71 of the control device according to the sixth embodiment performs routines executed by the CPU 71 of the second embodiment (excluding the routine shown in FIG. 9 and the fuel injection control routine for two-cycle self-ignition operation not shown). ), And the two-cycle control routine shown in FIG. 16 instead of FIG. 9 is started from step 1600 every time a minute constant crank angle (here, the crank angle is 1 degree = 1 CA). . Note that. In FIG. 16, the same steps as those shown in FIG. 9 are denoted by the same reference numerals, and the steps different from the steps of FIG. 9 will be described below.

  Step 1605: The processing of Step 1605 is performed after any cylinder is 90 degrees after top dead center (see Step 902) and the value of the flag X changes from “0” to “1”. After the timing when the absolute crank angle reaches 600 degrees for the first time (the timing when the value of the flag X2 is changed to “1” in step 615 in FIG. 6) (see step 904), 90 degrees after top dead center is reached. It is executed when the previous combustion of the cylinder in question is four-cycle spark ignition combustion. In step 1605, the CPU 71 obtains the combustion gas temperature compensation fuel injection reduction amount tausbbse from the table Maptausbbse (NE, PM). Thereby, as will be described later, the fuel injection amount is reduced by the combustion gas temperature compensation fuel injection reduction amount tausbbse. According to the table Maptausbbse (NE, PM), the combustion gas temperature compensation fuel injection reduction amount tausbbse becomes, for example, a larger value as the engine rotational speed NE is larger, and a smaller value as the intake pipe pressure PM is larger. To be determined.

  The fuel injection amount is reduced by the combustion gas temperature compensating fuel injection reduction amount tausbbse in this way, assuming that the previous combustion is combustion by four-cycle spark ignition operation, the combustion gas temperature is two-cycle steady operation by self-ignition. Because it is higher than the combustion gas temperature at the time, the self-ignition timing is prevented from becoming premature by reducing the fuel injection amount (preventing premature ignition) and the combustion gas obtained by the self-ignition combustion This is because the temperature of the gas is equal to the combustion gas temperature during the two-cycle steady operation.

  At the present time, any cylinder is 90 degrees after top dead center, and after the timing when the absolute crank angle reaches 600 degrees for the first time after the value of the flag X changes from “0” to “1”. Furthermore, if the previous combustion of the cylinder that has reached 90 degrees after the top dead center is not a four-cycle spark ignition combustion, the processing of step 1610 is performed, whereby the combustion gas temperature compensation fuel injection reduction amount tausbbse is “ 0 "is set. That is, the fuel injection amount is not reduced.

  Step 1615: The processing of Step 1615 is further executed when at least one of the intake valve 32 and the exhaust valve 34 of another cylinder currently operated in the 4-cycle spark ignition operation system is open. (See step 916.) In step 1615, the CPU 71 obtains the interference compensation fuel injection reduction amount tausbkan from the table Maptausbkan (θkan, PM). In this case, the interference compensation fuel injection reduction amount tausbkan is determined by the table Maptausbkan (θkan, PM) so as to increase as the interference period θkan increases and to decrease as the intake pipe pressure PM increases. Thereby, as will be described later, the fuel injection amount is reduced by the interference compensation fuel injection reduction amount tausbkan.

  This step 1615 is actually executed when the first cylinder starts to operate for the first time by the two-cycle self-ignition operation method (see the timing indicated by reference numeral t1 in FIG. 5). At this time, since the second cylinder is in the four-cycle spark ignition operation and at least one of the valves is open, the amount of fresh air to be introduced into the first cylinder decreases, and thus the scavenging amount of the first cylinder. The combustion gas temperature before compression becomes too high. Accordingly, in step 1615, the heat generation amount is reduced by reducing the fuel injection amount. As a result, the temperature of the combustion gas obtained through self-ignition combustion becomes equivalent to the combustion gas temperature during two-cycle steady operation.

  Step 1620: Step 1620 is executed when the processing of Step 1615 is executed. The fuel injection increase amount tauext for non-opening compensation is set to “0” in this step 1620.

  Step 1625: The processing in step 1625 is performed at the current time when any cylinder is 90 degrees after top dead center and the absolute crank angle is 600 degrees only after the value of the flag X changes from “0” to “1”. There is no open valve among the intake valves 32 and the exhaust valves 34 of other cylinders that are operating in the four-cycle spark ignition operation method at the present time after the arrival timing, and immediately before or immediately before This is executed when there is no scavenging stroke of other cylinders.

  Through the processing in step 1625, the fuel injection increase amount tauext without valve opening compensation is obtained based on the table Maptauext (θnashi, PM). In this case, the no-opening compensation fuel injection increase amount tauext is determined by the table Maptauext (θnashi, PM) so as to increase as the non-opening period θnashi increases and the intake pipe pressure PM increases.

  This step 1625 is actually executed when the third cylinder starts to be operated for the first time by the two-cycle self-ignition operation method (see the timing indicated by the symbol t3 in FIG. 5). In this case, since the scavenging strokes of the other cylinders do not exist immediately before, most of the exhaust gas discharged from the engine 10 has already flowed downstream. Accordingly, since the exhaust pressure is smaller than that in the two-cycle steady operation, the scavenging amount increases. No-opening compensation fuel injection increase amount tauext is generated by increasing the fuel injection amount so that the temperature of the combustion gas generated by the combustion of the third cylinder does not become too low due to the increase of the scavenging amount This is an increase in the amount of heat generated. Due to this increase, the combustion gas temperature can be made equal to the combustion gas temperature during the two-cycle steady operation, so that torque fluctuations generated by the engine are reduced.

  Step 1630: Step 1630 is executed when the processing of Step 1625 is executed. The interference compensation fuel injection reduction amount tausbkan is set to “0” in step 1630.

  Step 1635: Step 1635 is when the two-cycle self-ignition operation is being performed regularly (during the two-cycle steady operation) or when the intake and exhaust states are the same as those during the two-cycle steady operation. To be executed. By the processing of step 1635, the interference compensation fuel injection decrease amount tausbkan and the non-valve opening compensation fuel injection increase amount tauext are both set to “0”.

  Step 1640: Fuel injection temperature decrease fuel injection decrease amount tausbbse and interference compensation fuel injection decrease amount tausbkan are subtracted from basic fuel injection amount taubse, and non-valve compensation fuel injection increase amount tauext is added to the decreased amount The amount is set as the final fuel injection amount tau.

Step 1645: The final exhaust valve closing timing EC is set to a timing when the basic scavenging period θbse has elapsed from the intake valve opening timing IO.
Step 1650: The final intake valve closing timing IC is set to a timing after elapse of a certain period θconst from the exhaust valve closing timing EC.

Step 1655: Similar to Step 932 in FIG. 9, the exhaust valve 34 of the cylinder which is 90 degrees after the top dead center is opened at the exhaust valve opening timing EO and at the exhaust valve closing timing EC. The timing for sending the output signal to the drive circuit 38 is set so that the intake valve 32 of the cylinder is opened at the intake valve opening timing IO and closed at the intake valve closing timing IC. To do.
Step 1660: The injector 37 is opened for the period of the fuel injection amount tau from the time when the crank angle of the cylinder which is 90 degrees after the top dead center becomes the fuel injection timing θinj, and the fuel of the fuel injection amount tau is injected. Set as follows.

  As described above, the control device according to this embodiment is configured so that the fuel injection amount for the cylinder at the time of starting switching the cylinder operation method from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method is the same at the same point. The fuel injection amount at the time when the valve timing control means and the fuel injection control means are steadily operated by the two-cycle self-ignition operation method under the same torque as that required for There is provided a switching-time fuel injection amount control means for changing the fuel injection amount for the cylinder so that the fuel injection amount is smaller by a predetermined amount (= tausbbse + tausbkan-tauext) than taubse).

  As a result, the increase in the combustion gas temperature in the first two-cycle operation method after switching the operation method is suppressed, and the two-cycle self-ignition operation method using the combustion gas at the same temperature as in the two-cycle steady operation from the next cycle. Driving is performed. Therefore, since self-ignition can be generated at an ideal time after the switching of the driving method, torque fluctuation can be suppressed.

  Further, the switching fuel injection amount control means of the present embodiment operates at the time when the operation mode of the cylinder starts to be switched from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method. The predetermined amount is changed according to the open / close states of the intake valves and exhaust valves of the other cylinders during and immediately before the scavenging stroke of any cylinder that starts the operation (see FIG. 9 in FIG. 16). (See step 916, step 934 of the routine shown and the steps performed according to the positive determination at these steps). As a result, even if the scavenging amount at the time of switching between the 4-cycle and 2-cycle operation is different from that at the 2-cycle steady operation, the combustion gas temperature can be made equal to the combustion gas temperature at the 2-cycle steady operation. Torque fluctuations during cycle-2 cycle switching can be suppressed.

  Note that the basic fuel injection amount taubse is necessarily reduced depending on the magnitude relationship between the fuel injection reduction amount tausbbse for combustion gas temperature compensation, the fuel injection reduction amount tausbkan for interference compensation, and the fuel injection increase amount tauext for no valve opening compensation. Is not limited. That is, the predetermined amount may be a negative amount. That the predetermined amount is a negative amount means that the basic fuel injection amount taubse is increased.

(Seventh embodiment)
Next, a control device for an internal combustion engine according to a seventh embodiment will be described. The control device of the second embodiment described above changes the scavenging period by changing the opening and closing timings of the intake valve 32 and the exhaust valve 34 at the time of switching between 4 cycles and 2 cycles. The amount of torque was secured to suppress fluctuations in torque generated by the internal combustion engine 10. The control device of the sixth embodiment described above controls the fuel injection amount to quickly bring the combustion gas temperature close to the combustion gas temperature during the two-cycle steady operation, thereby suppressing fluctuations in torque generated by the internal combustion engine 10. . On the other hand, in the seventh embodiment, for a cylinder whose scavenging amount is likely to change due to a change in the scavenging amount such as the scavenging period and supercharging pressure, the scavenging period is changed and the scavenging amount is determined by changing the factor. For the cylinder in which the scavenging amount is difficult to change, the variation of the torque generated by the internal combustion engine 10 is suppressed by changing the fuel injection amount.

  Specifically, the CPU 71 of the control device according to the seventh embodiment performs routines executed by the CPU 71 of the second embodiment (excluding the routine shown in FIG. 9 and the fuel injection control routine for two-cycle self-ignition operation not shown). ) And the control routine for two cycles shown in FIGS. 17 and 18 instead of FIG. 9 is started from step 1700 every time a minute constant crank angle (here, crank angle 1 degree = 1 CA) elapses. It has become. In the following, the steps in FIGS. 17 and 18 that are the same as the steps shown in FIG. 9 or FIG. 16 are given the same reference numerals, and detailed descriptions thereof are omitted.

  When the conditions of Step 902, Step 904, and Step 906 following Step 1700 are satisfied (when the conditions for driving in the two-cycle self-ignition operation method are satisfied), the CPU 71 executes Steps 908 to 911. Execute the process. Next, the CPU 71 proceeds to step 1705, starts the processing of the subroutine shown in FIG. 18 from step 1800 and proceeds to step 916. At this time, if at least one of the intake valve 32 and the exhaust valve 34 of the other cylinders currently operated in the 4-cycle spark ignition operation system is open, the CPU 71 interferes with the processing of step 918 and step 920. The period θkan is calculated.

  Next, the CPU 71 proceeds to step 1805 to obtain the fuel injection reduction amount tausub from the table Maptausub (θkan, PM). In step 1810, the CPU 71 sets the scavenging extension period θext to “0”, and in step 1815, sets the scavenging shortening period θshort to “0”. Thereafter, the CPU 71 performs the processing from step 1710 to step 1730 in FIG. 17 through step 1895 as follows, and once this routine is finished in step 1795.

Step 1710: The exhaust valve closing timing EC is set to a timing that has elapsed from the intake valve opening timing IO by a period obtained by subtracting the scavenging shortening period θshort from the period obtained by adding the basic scavenging period θbse and the scavenging extension period θext. . In this case, since the scavenging extension period θext and the scavenging shortening period θshort are set to “0” in the previous step 1810 and step 1815, the scavenging period is a period that coincides with the basic scavenging period θbse.
Step 1715: The final intake valve closing timing IC is set to a timing after elapse of a certain period θconst from the exhaust valve closing timing EC.
Step 1720: An amount obtained by subtracting the fuel injection reduction amount tausub from the basic fuel injection amount taubse is set as the final fuel injection amount tau.

Step 1725: Similar to Step 932 in FIG. 9, the exhaust valve 34 of the cylinder which is 90 degrees after the top dead center is opened at the exhaust valve opening timing EO and at the exhaust valve closing timing EC. The timing for sending the output signal to the drive circuit 38 is set so that the intake valve 32 of the cylinder is opened at the intake valve opening timing IO and closed at the intake valve closing timing IC. To do.
Step 1730: The injector 37 is opened for the period of the fuel injection amount tau from the time when the crank angle of the cylinder which is 90 degrees after the top dead center becomes the fuel injection timing θinj, and the fuel of the fuel injection amount tau is injected. Set as follows.

  The series of processing described above is actually executed when the first cylinder starts to be operated for the first time by the two-cycle self-ignition operation method (see the timing indicated by reference numeral t1 in FIG. 5). At this time, since the second cylinder is in the four-cycle spark ignition operation and the intake valve 32 is open, the amount of fresh air to be introduced into the first cylinder is reduced, so that the scavenging of the first cylinder is performed. The amount is insufficient and the combustion gas temperature becomes too high.

  In order to cope with this, the first embodiment increases the supercharging pressure, and the second embodiment extends the scavenging period. However, even if the boost pressure is increased or the scavenging period is extended, the second cylinder that performs the four-cycle spark ignition operation is eventually deprived of fresh air, so that sufficient fresh air cannot be introduced into the first cylinder. The scavenging amount of one cylinder may be insufficient. In contrast, in this embodiment, the fuel injection amount is set to a value obtained by reducing the fuel injection amount by the fuel injection reduction amount tausub from the basic fuel injection amount taubse. Therefore, the temperature of the combustion gas by the first self-ignition combustion after switching the operation of the first cylinder is set. It is possible to make the temperature close to the combustion gas temperature during the two-cycle steady operation. As a result, stable self-ignition combustion is performed from the next cycle. The fuel injection reduction amount tausub includes the above-described combustion gas temperature compensation fuel injection reduction amount tausbbse.

  On the other hand, when the CPU 71 proceeds to step 916 in FIG. 18, if the condition of step 916 is not satisfied, the CPU 71 determines “No” in step 916 and proceeds to step 934. At this time, if the scavenging stroke of another cylinder does not exist at the present time or immediately before, the CPU 71 determines “Yes” in step 934, and calculates the valve-opening-free period θnashi in step 936.

  Next, the CPU 71 proceeds to step 938 to calculate the scavenging shortening period θshort from Mapθshort (θnashi, PM), and proceeds to step 1820 to obtain the scavenging extension period θext from the table Mapθext (PM, NE). The scavenging extension period θext is the same kind of period as the combustion gas temperature compensation scavenging extension period θexbse described above. Then, after setting the fuel injection reduction amount tausub to “0” in step 1825, the CPU 71 performs the processing of step 1710 to step 1730 in FIG. 17 via step 1895, and once this routine is executed in step 1795. finish. Thus, the scavenging period θsoki is a period obtained by adding the scavenging extension period θext to the scavenging period θbse in the two-cycle steady operation and reducing the scavenging shortening period θshort from the same period. Further, the fuel injection amount is the same as the fuel injection amount taubse during the two-cycle steady operation.

  The series of processes following the affirmative determination in step 934 of FIG. 18 described above is actually executed when the third cylinder starts to operate for the first time by the two-cycle self-ignition operation method (at symbol t3 in FIG. 5). (See timing shown.) In this case, since the scavenging strokes of the other cylinders do not exist immediately before, most of the exhaust gas discharged from the engine 10 has already flowed downstream. Accordingly, since the exhaust pressure is smaller than that in the two-cycle steady operation, the scavenging amount increases.

  On the other hand, since the control device of the present embodiment reduces the scavenging period by the scavenging shortening period θshort, the scavenging amount is appropriate. In addition, since the previous combustion was a 4-cycle spark ignition combustion, the combustion gas temperature is high. Therefore, by extending the scavenging period by the scavenging extension period θext, the combustion gas temperature is equivalent to the combustion gas temperature during two-cycle steady operation. Become. As a result, fluctuations in torque generated by the engine 10 can be suppressed.

  Further, when the CPU 71 proceeds to step 934 in FIG. 18, if the condition of step 934 is not satisfied, the CPU 71 determines “No” in step 934 and proceeds to step 912. At this time, if the previous combustion of the cylinder that has reached 90 degrees after the top dead center is four-cycle spark ignition combustion, the CPU 71 determines “Yes” in step 912 and proceeds to step 1830 to advance the scavenging shortening period θshort. Is set to “0”.

  Next, in step 1835, the CPU 71 obtains the scavenging extension period θext in the same manner as in step 1820, and in subsequent step 1840, sets the value of the fuel injection reduction amount tausub to “0”. Thereafter, the CPU 71 performs the processing from step 1710 to step 1730 in FIG. 17 via step 1895, and once ends this routine in step 1795.

  Accordingly, the scavenging period θsoki is a period obtained by adding the scavenging extension period θext to the scavenging period θbse in the two-cycle steady operation. Further, the fuel injection amount is the same as the basic fuel injection amount taubse during the two-cycle steady operation.

  The series of processes following the affirmative determination in step 912 of FIG. 18 described above is actually executed when the second cylinder starts to operate by the two-cycle self-ignition operation method for the first time (at symbol t5 in FIG. 5). (See timing shown.) At this time, since the previous combustion was four-cycle spark ignition combustion, the combustion gas temperature is high. Therefore, by extending the scavenging period by the scavenging extension period θext, the combustion gas temperature is equivalent to the combustion gas temperature during two-cycle steady operation. It becomes. As a result, fluctuations in torque generated by the engine 10 can be suppressed.

  When the conditions of step 916, step 934, and step 912 are not satisfied (that is, during the two-cycle steady operation), the CPU 71 performs the processing of step 1845 to step 1855, thereby reducing the scavenging shortening period θshort and scavenging. Each value of the extension period θext and the fuel injection reduction amount tausub is set to “0”. As a result, the scavenging period and the fuel injection amount necessary for the two-cycle steady operation can be obtained.

  Thus, the control apparatus for an internal combustion engine according to the seventh embodiment is the same as the two-cycle self-ignition operation method when the operation method of the cylinder starts to be switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method. If no scavenging stroke of another cylinder exists immediately before or after the scavenging stroke of any cylinder that starts the operation according to the above, the cylinders in the scavenging stroke during the scavenging stroke in the two-cycle self-ignition operation method The scavenging amount that is the amount of exhausted gas, and the scavenging amount of the same cylinder is the same as the torque required for the same engine at the same time, according to the two-cycle auto-ignition operation method A factor that determines the scavenging amount is controlled so as to approach the scavenging amount at the time when the valve timing control means and the fuel injection control means are steadily operated. And a scavenging amount control means (step 934 to step 938 of FIG. 17 and FIG. 18) for.

  In this case, the amount of scavenging can be easily adjusted by changing the factor that changes the amount of scavenging, so that torque fluctuation during operation system switching can be suppressed while obtaining the required torque without changing the fuel injection amount. can do.

  Further, the present control device scavenges any cylinder that starts operation by the two-cycle self-ignition operation method at the time when the operation method of the cylinder starts to be switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method. When the stroke overlaps the intake stroke or exhaust stroke of another cylinder operated by the same 4-cycle spark ignition operation method, the fuel injection amount for the arbitrary cylinder is required for the engine at the same time. Under the same torque as the torque, the fuel injection amount is different from the fuel injection amount at the time when the valve timing control means and the fuel injection control means are regularly operated by the two-cycle self-ignition operation method. Switching fuel injection amount control means (steps 916 to 920 in FIGS. 17 and 18; and And it includes a step 1805).

  In this case, even if the factor for changing the scavenging amount is changed, the scavenging amount is unlikely to change due to fresh air being taken away by other cylinders or combustion gas being discharged from other cylinders. It is advantageous to bring the combustion gas temperature closer to the combustion gas temperature during two-cycle steady operation by adjusting the amount. Accordingly, the combustion gas temperature at the start of the two-cycle self-ignition operation becomes an appropriate temperature, so that the next self-ignition combustion is also stably performed. As a result, the cycle-to-cycle variation in torque generated by the engine can be suppressed.

  In the embodiment of the present invention, Steps 1820 and 1835 are changed in the same manner as Step 1605 of FIG. 16 to obtain the combustion gas temperature compensation fuel injection reduction amount tausbbse. Further, Step 1720 of FIG. = Taubse−tausub−tausubbse ”may be calculated.

  As described above, according to each embodiment of the control apparatus for an internal combustion engine according to the present invention, when the operation method is switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method, the torque generated by the engine 10 Can be reduced.

  In addition, this invention is not limited to said each embodiment, A various modification can be employ | adopted within the scope of the present invention. For example, the internal combustion engine 10 may be provided with a turbocharger, and supercharging by the turbocharger may be performed in place of or in addition to supercharging by the supercharger 46. In this case, a supercharging pressure adjustment valve that adjusts the amount of exhaust gas flowing into the turbine of the turbocharger may be provided, thereby controlling the intake pipe pressure (supercharging pressure). Moreover, although the said control apparatus was applied to the internal combustion engine of 3 cylinders, the number of cylinders of the internal combustion engine applied is not limited to this. Furthermore, when the operation is performed by the two-cycle self-ignition operation method, a spark may be generated supplementarily from the spark plug 35.

1 is a schematic diagram of an internal combustion engine to which a configuration common to each embodiment of a control device for an internal combustion engine according to the present invention and the control device are applied. It is a flowchart showing the driving | operation system determination routine which CPU shown in FIG. 1 performs. 4 is a flowchart showing a 4-cycle valve control routine executed by a CPU shown in FIG. 1. It is a flowchart showing the supercharger control routine which CPU shown in FIG. 1 performs. 4 is a time chart showing in-cylinder pressures of each cylinder, opening / closing timings of intake valves and exhaust valves, and supercharging pressure when the operation method is switched from the four-cycle spark ignition operation method to the two-cycle self-ignition operation method. It is a flowchart showing the flag operation routine which CPU shown in FIG. 1 performs. It is a flowchart showing the valve control routine for 2 cycles which CPU shown in FIG. 1 performs. It is a flowchart showing the supercharger control routine which CPU which concerns on 2nd Embodiment of this invention performs. It is a flowchart showing the valve control routine for 2 cycles which CPU which concerns on 2nd Embodiment of this invention performs. It is a flowchart showing a part of 2-cycle valve | bulb control routine which CPU which concerns on 3rd Embodiment of this invention performs. It is a time chart for demonstrating the action | operation of the control apparatus which concerns on 3rd Embodiment of this invention. It is a time chart for demonstrating the action | operation of the control apparatus which concerns on 4th Embodiment of this invention. It is a flowchart showing the fuel injection control routine for 2 cycles which CPU which concerns on 4th Embodiment of this invention performs. It is a time chart for demonstrating the action | operation of the control apparatus which concerns on 5th Embodiment of this invention. It is a flowchart showing the control routine for 2 cycles which CPU which concerns on 5th Embodiment of this invention performs. It is a flowchart showing the control routine for 2 cycles which CPU which concerns on 6th Embodiment of this invention performs. It is a flowchart showing the control routine for 2 cycles which CPU which concerns on 7th Embodiment of this invention performs. It is a flowchart showing the control routine for 2 cycles which CPU which concerns on 7th Embodiment of this invention performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Multi-cylinder gasoline injection internal combustion engine, 21 ... Cylinder, 22 ... Piston, 23 ... Connecting rod, 24 ... Crankshaft, 25 ... Combustion chamber, 31 ... Intake port, 32 ... Intake valve, 32a ... Intake valve drive mechanism, 33 Exhaust port 34 ... Exhaust valve 34a Exhaust valve drive mechanism 35 ... Spark plug 36 ... Igniter 37 ... Injector 38 ... Drive circuit 45 ... Air bypass valve (ABV) 46 ... Supercharger 46a ... Supercharger clutch, 47 ... intercooler, 48 ... throttle valve, 48a ... throttle valve actuator, 49 ... bypass passage, 63 ... crank position sensor, 67 ... accelerator opening sensor, 70 ... electric control device, 71 ... CPU.

Claims (12)

A 4-cycle spark ignition operation system that repeats an exhaust stroke, an intake stroke, a compression stroke, and a combustion stroke by spark ignition every time the crank angle rotates 720 degrees, and an exhaust stroke, a scavenging stroke, and an intake air each time the crank angle rotates 360 degrees A control apparatus for a multi-cylinder internal combustion engine comprising a plurality of cylinders that can be operated by a two-cycle self-ignition operation system that repeats a combustion stroke by a stroke, a compression stroke, and self-ignition,
An operation method determining means for determining which of the four-cycle spark ignition operation method and the two-cycle self-ignition operation method is to be performed based on the operation state of the engine;
Valve timing control means for controlling the opening and closing timing of each intake valve and each exhaust valve of the plurality of cylinders based on the torque required for the engine and the determined operation method;
The scavenging amount that is the amount of gas discharged from the cylinder in the scavenging stroke during the scavenging stroke in the two-cycle self-ignition operation method, and the operation method of the cylinder is changed from the four-cycle spark ignition operation method to the two-cycle self-ignition method. When the scavenging amount at the start of switching to the ignition operation method is the same as the torque required for the same engine at the same time, the operation by the two-cycle self-ignition operation method is made steady by the valve timing control means. Scavenging amount control means for controlling a factor that determines the scavenging amount so as to approach the scavenging amount at the time of being performed automatically,
The control apparatus of the internal combustion engine provided with. A control device for an internal combustion engine according to claim 1,
A supercharging pressure control means for controlling the supercharging pressure of the engine based on the torque required for the engine and the determined operation method;
The scavenging amount control means includes
When the operation mode of the cylinder starts to be switched from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, the scavenging stroke of any cylinder that starts operation by the 2-cycle self-ignition operation method is the same as the 4-cycle spark ignition method. In the case where it overlaps with the intake stroke of another cylinder operated by the operation method, the supercharging pressure is the same two-cycle auto-ignition operation method under the same torque as that required for the engine at the same time. By controlling the supercharging pressure control means so as to be larger than the supercharging pressure controlled by the supercharging pressure control means at the time when the operation by is constantly performed, the supercharging pressure is reduced to the scavenging amount. A control apparatus for an internal combustion engine that controls the engine as a factor for determining the engine. The control apparatus for an internal combustion engine according to claim 1,
The scavenging amount control means includes
A control apparatus for an internal combustion engine configured to change opening / closing timings of the intake valves and the exhaust valves of the plurality of cylinders as a factor for determining the scavenging amount. The control apparatus for an internal combustion engine according to claim 3,
The scavenging amount control means includes
At the time of starting to switch the operation mode of the cylinder from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, during the scavenging stroke of any cylinder that starts operation by the 2-cycle self-ignition operation method and immediately before the scavenging stroke The control device for an internal combustion engine configured to change the opening / closing timings of the intake valves and exhaust valves of the arbitrary cylinders according to the open / close states of the intake valves and exhaust valves of the other cylinders. The control apparatus for an internal combustion engine according to claim 4,
The scavenging amount control means includes
When the operation mode of the cylinder starts to be switched from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, the scavenging stroke of any cylinder that starts operation by the 2-cycle self-ignition operation method is the same as the 4-cycle spark ignition method. If it overlaps with the intake stroke or exhaust stroke of another cylinder operated by the operation method, the same scavenging stroke period is the same two cycles under the same torque as that required for the engine at the same time. The intake valve opening timing of any cylinder and the scavenging stroke at the time when the operation by the self-ignition operation system is steadily performed by the valve timing control means, and a predetermined extension period is added. A control device for an internal combustion engine configured to change at least one of the exhaust valve closing timings of the arbitrary cylinder. The control apparatus for an internal combustion engine according to claim 4,
The scavenging amount control means includes
Other than occurring at the time of starting to switch the operation mode of the cylinder from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, immediately before the combustion stroke of any cylinder that starts operation by the 2-cycle self-ignition operation method When the combustion in the combustion stroke of the cylinder is combustion by the 4-cycle spark point operation method, the scavenging stroke period is the same under the same torque as that required for the engine at the same time. The intake valve opening of any cylinder is set so as to be a period obtained by subtracting a predetermined shortening period from the scavenging stroke period at the time when the operation by the two-cycle self-ignition operation system is steadily performed by the valve timing control means. A control device for an internal combustion engine configured to change at least one of a timing and an exhaust valve closing timing of the arbitrary cylinder. The control apparatus for an internal combustion engine according to any one of claims 3 to 6, wherein the scavenging amount control means includes:
The exhaust valve closing timing of the cylinder in which the exhaust valve opening timing of the cylinder that performs combustion after the two cylinders that continuously perform combustion by the two-cycle self-ignition operation method is the first of the two cylinders that performs combustion A control device for an internal combustion engine configured to change an exhaust valve opening timing of a cylinder that performs combustion thereafter so as to arrive later than the timing. The control apparatus for an internal combustion engine according to any one of claims 3 to 6, wherein the scavenging amount control means includes:
The exhaust valve closing timing of the cylinder in which the exhaust valve opening timing of the cylinder that performs combustion after the two cylinders that continuously perform combustion by the two-cycle self-ignition operation method is the first of the two cylinders that performs combustion A control device for an internal combustion engine configured to change an exhaust valve closing timing of a cylinder performing combustion earlier so as to arrive later than the timing. A control device for an internal combustion engine according to any one of claims 3 to 8,
Fuel injection control means for determining a fuel injection amount based on the torque required for the engine and the determined operation method, and injecting the determined fuel injection amount into the cylinder in the combustion stroke When,
When the scavenging amount control means controls the exhaust valve closing timing of an arbitrary cylinder that starts operation by the two-cycle self-ignition operation method, the fuel injection control means according to the controlled exhaust valve closing timing Injection timing control means for changing the injection start timing of the fuel injected from
The control apparatus of the internal combustion engine provided with. A 4-cycle spark ignition operation system that repeats an exhaust stroke, an intake stroke, a compression stroke, and a combustion stroke by spark ignition every time the crank angle rotates 720 degrees, and an exhaust stroke, a scavenging stroke, and an intake air each time the crank angle rotates 360 degrees A control apparatus for a multi-cylinder internal combustion engine comprising a plurality of cylinders that can be operated by a two-cycle self-ignition operation system that repeats a combustion stroke by a stroke, a compression stroke, and self-ignition,
An operation method determining means for determining which of the four-cycle spark ignition operation method and the two-cycle self-ignition operation method is to be performed based on the operation state of the engine;
Valve timing control means for controlling the opening / closing timing of each intake valve and each exhaust valve of the plurality of cylinders based on the torque required for the engine and the determined operation method;
Fuel injection control means for determining a fuel injection amount based on the torque required for the engine and the determined operation method, and injecting the determined fuel injection amount into the cylinder in the combustion stroke When,
The fuel injection amount for the cylinder at the time of starting to switch the operation method of the cylinder from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method is the torque required for the engine at the same time. A fuel injection amount that is smaller by a predetermined amount than a fuel injection amount at the time when the valve timing control means and the fuel injection control means are regularly operated under the same torque under the two-cycle self-ignition operation method; A switching-time fuel injection amount control means for changing the fuel injection amount for the same cylinder,
The control apparatus of the internal combustion engine provided with. The control apparatus for an internal combustion engine according to claim 10,
The switching fuel injection amount control means is
At the time of starting to switch the operation mode of the cylinder from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, during the scavenging stroke of any cylinder that starts operation by the 2-cycle self-ignition operation method and immediately before the scavenging stroke The control apparatus for an internal combustion engine configured to change the predetermined amount according to the open / close states of the intake valves and exhaust valves of the other cylinders in FIG. A 4-cycle spark ignition operation system that repeats an exhaust stroke, an intake stroke, a compression stroke, and a combustion stroke by spark ignition every time the crank angle rotates 720 degrees, and an exhaust stroke, a scavenging stroke, and an intake air each time the crank angle rotates 360 degrees A control apparatus for a multi-cylinder internal combustion engine comprising a plurality of cylinders that can be operated by a two-cycle self-ignition operation system that repeats a combustion stroke by a stroke, a compression stroke, and self-ignition,
An operation method determining means for determining which of the four-cycle spark ignition operation method and the two-cycle self-ignition operation method is to be performed based on the operation state of the engine;
Valve timing control means for controlling the opening / closing timing of each intake valve and each exhaust valve of the plurality of cylinders based on the torque required for the engine and the determined operation method;
Fuel injection control means for determining a fuel injection amount based on the torque required for the engine and the determined operation method, and injecting the determined fuel injection amount into the cylinder in the combustion stroke When,
At the time when the operation mode of the cylinder starts to be switched from the 4-cycle spark ignition operation mode to the 2-cycle self-ignition operation mode, during the scavenging stroke or immediately before the scavenging stroke of any cylinder that starts operation by the 2-cycle self-ignition operation mode In the case where there is no scavenging stroke of other cylinders, the scavenging amount which is the amount of gas discharged from the cylinder in the scavenging stroke during the scavenging stroke in the two-cycle self-ignition operation method When the scavenging amount is the same as the torque required for the engine at the same time, the operation by the two-cycle self-ignition operation system is steadily performed by the valve timing control means and the fuel injection control means. A scavenging amount control means for controlling a factor that determines the scavenging amount so as to approach the scavenging amount at the time of being performed;
When the operation mode of the cylinder starts to be switched from the 4-cycle spark ignition operation method to the 2-cycle self-ignition operation method, the scavenging stroke of any cylinder that starts operation by the 2-cycle self-ignition operation method is the same as the 4-cycle spark ignition method. When it overlaps with the intake stroke or exhaust stroke of another cylinder operated by the operation method, the fuel injection amount for the arbitrary cylinder is under the same torque as the torque required for the engine at the same time. The fuel injection amount is set so that the fuel injection amount is different from the fuel injection amount at the time when the operation by the two-cycle self-ignition operation method is regularly performed by the valve timing control means and the fuel injection control means. A switching fuel injection amount control means to be changed;
The control apparatus of the internal combustion engine provided with.

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