JP4682905B2 - Control device for premixed compression self-ignition internal combustion engine - Google Patents

Description

  The present invention forms a mixed gas containing air, fuel, and combustion gas (burned gas or exhaust gas) in the combustion chamber, and compresses the formed mixed gas by the compression operation of the piston, thereby self-igniting. The present invention relates to a control device for a premixed compression self-ignition internal combustion engine operated by a combustion method.

  2. Description of the Related Art Conventionally, as a method for operating an internal combustion engine, a premixed compression self-ignition method is known in which a mixed gas formed in a combustion chamber is compressed to self-ignite and burn within a very short period. In an internal combustion engine operated by this premixed compression self-ignition system, when the temperature of the mixed gas exceeds a predetermined threshold temperature (self-ignition temperature) during the period in which the mixed gas is compressed by the piston, Starts burning.

  This self-ignition temperature is extremely high compared to the atmospheric temperature. Therefore, it is difficult to raise the temperature of the mixed gas composed of air and fuel to the self-ignition temperature only by compression by the piston. Therefore, one of the conventional control devices provides a negative overlap period in which both the exhaust valve and the intake valve are closed when shifting from the exhaust stroke to the intake stroke. The combustion gas generated by the combustion of the mixed gas in the cycle is left in the combustion chamber (see, for example, Patent Document 1).

According to this conventional control device, since the high-temperature combustion gas left in the combustion chamber is included in the newly formed mixed gas, the temperature of the mixed gas at the time when compression of the formed mixed gas starts ( The compression start temperature) is sufficiently increased. As a result, the temperature of the mixed gas can surely reach the self-ignition temperature by the compression of the piston, so that the mixed gas can be surely self-ignited.
JP 11-264319 A

  By the way, the conventional control apparatus determines the negative overlap period according to the operating state of the internal combustion engine. Therefore, at least when the operating state of the internal combustion engine does not change, a constant amount of combustion gas can remain in the combustion chamber, so that the timing at which the mixed gas self-ignites (self-ignition timing) is set to the operating state. Accordingly, it is considered that it can always coincide with the scheduled timing (scheduled self-ignition timing).

  On the other hand, even when the operating condition is constant, the compression start temperature is relatively different from the planned temperature for some reason, so that the self-ignition timing is relatively different from the planned self-ignition timing. There is. Hereinafter, an example of such a case will be described with reference to FIG.

  In the example of FIG. 1, as indicated by the solid line L1, when the operating state is constant, the self-ignition timing S coincides with the scheduled auto-ignition timing Sep until the combustion cycle N1, and the auto-ignition timing S reaches the scheduled auto-ignition timing at the combustion cycle N2. It is assumed that the timing is relatively delayed from the ignition timing Sep.

  In this case, in the combustion cycle N2, after the combustion gas is generated by the combustion of the mixed gas, the combustion gas pushes down the piston, so that the period during which work is performed on the piston becomes shorter than the scheduled period. Accordingly, since the total amount of work that the combustion gas performs on the piston is reduced, the temperature of the combustion gas does not decrease so much even when the expansion stroke is completed. Furthermore, since the period during which the heat of the combustion gas is transmitted to the wall surface constituting the combustion chamber is also shorter than the scheduled period, the total amount of heat transmitted is reduced, and the temperature reduction of the combustion gas is further suppressed. Therefore, as indicated by the one-dot chain line L2, the temperature T of the combustion gas at the time when the combustion cycle ends is higher than the planned temperature (scheduled combustion gas temperature) Tep.

  In the next combustion cycle N3, since the combustion gas having a temperature higher than the planned combustion gas temperature Tep is included in the mixed gas, the compression start temperature becomes higher than the planned temperature. As a result, the timing at which the temperature of the mixed gas reaches the self-ignition temperature is advanced, so that the self-ignition timing is advanced from the scheduled self-ignition timing Sep. As a result, the total amount of work performed on the piston by the combustion gas increases, and the total amount of heat transferred from the combustion gas to the wall surface constituting the combustion chamber increases, so that the combustion gas at the end of the combustion cycle is increased. The temperature becomes lower than the planned combustion gas temperature Tep.

  Thereafter, at the next combustion cycle N4, since the combustion gas having a temperature lower than the planned combustion gas temperature Tep is included in the mixed gas, the compression start temperature becomes lower than the planned temperature. As a result, the timing at which the temperature of the mixed gas reaches the self-ignition temperature is delayed, and the self-ignition timing is delayed from the scheduled self-ignition timing Sep. As a result, the temperature T of the combustion gas at the end of the combustion cycle becomes higher than the scheduled combustion gas temperature Tep.

  As described above, once the self-ignition timing S is different from the scheduled self-ignition timing Sep, the self-ignition timing S is alternately changed to the retarded side and the advanced side with respect to the scheduled self-ignition timing Sep for each combustion cycle. It becomes easy to change. Further, when the self-ignition timing S changes, the output shaft torque changes. Therefore, according to the conventional control device, there is a problem that the state in which the output shaft torque fluctuates relatively with the progress of the combustion cycle tends to continue.

  The present invention has been made in order to address the above-described problems, and one of the purposes thereof is a premixing compression apparatus capable of preventing a state in which the output shaft torque fluctuates relatively greatly from continuing. An object of the present invention is to provide a control device for an ignition type internal combustion engine.

  In order to achieve this object, a control device for a premixed compression self-ignition internal combustion engine according to the present invention forms a mixed gas containing air, fuel, and combustion gas in a combustion chamber and uses the formed mixed gas. The present invention is applied to a premixed compression self-ignition internal combustion engine that is operated by a method in which it is compressed by a compression operation of a piston and burned by self-ignition.

A control device for a premixed compression self-ignition internal combustion engine according to the present invention comprises:
A self-ignition timing acquisition means for acquiring a self-ignition timing that is a timing at which the mixed gas self-ignites,
Generated in the previous combustion cycle so that the earlier the self-ignition timing in the current combustion cycle acquired by the self-ignition timing acquisition means, the greater the amount of combustion gas contained in the mixed gas in the next combustion cycle Combustion gas supply means for supplying the generated combustion gas to the mixed gas in the next combustion cycle ;
Is provided.

  According to this, when the self-ignition timing of the current combustion cycle is advanced by a relatively large angle, that is, when the temperature of the combustion gas at the end of the current combustion cycle is lower than the expected temperature, A large amount of combustion gas is included in the gas mixture of the next combustion cycle. Thereby, since it can prevent that compression start temperature becomes low too much, it can prevent that the self-ignition timing of the next combustion cycle retards too much.

  On the other hand, if the self-ignition timing of the current combustion cycle is retarded by a relatively large amount, that is, if the temperature of the combustion gas at the end of the current combustion cycle is higher than the expected temperature, a relatively small amount Are included in the gas mixture of the next combustion cycle. Thereby, since it can prevent that compression start temperature becomes high too much, it can prevent that the self-ignition timing of the next combustion cycle advances too much.

  Therefore, according to the present invention, the amount of fluctuation of the self-ignition timing with the progress of the combustion cycle is determined so that a constant amount of combustion gas is supplied to the next combustion cycle regardless of the self-ignition timing of the current combustion cycle. It can be made smaller compared to the case. In other words, it is possible to prevent the state where the output shaft torque fluctuates relatively large from continuing.

In this case, if the internal combustion engine is an internal combustion engine (four-cycle premixed compression self-ignition internal combustion engine) that is operated by a four-cycle system, the combustion gas supply means is adjusted by “means for adjusting the negative overlap period”. Can be configured.
Here, in the negative overlap period, from the timing of closing the exhaust valve that has been opened for exhausting (exhaust valve closing timing), the timing for opening the intake valve to perform intake thereafter This is a period up to (intake valve opening timing) (that is, a period in which both the exhaust valve and the intake valve are closed when shifting from the exhaust stroke to the intake stroke). Therefore, the negative overlap period is adjusted by changing the exhaust valve opening timing to start the negative overlap period and / or the intake valve opening timing to end the negative overlap period. The

Further, if the internal combustion engine is an internal combustion engine (two-cycle premixed compression self-ignition internal combustion engine) operated by a two-cycle system, the combustion gas supply means may be constituted by “means for adjusting the scavenging period”. it can.
Here, in the scavenging period, scavenging is terminated after the timing at which the intake valve is opened to perform scavenging in the state where the exhaust valve is opened to perform exhaust (intake valve opening timing). This is a period up to the timing of closing the exhaust valve to perform only intake (exhaust valve closing timing) (that is, the period in which both the exhaust valve and the intake valve are opened after combustion occurs). Accordingly, the scavenging period is adjusted by changing the intake valve opening timing for starting the scavenging period and / or the exhaust valve closing timing for ending the scavenging stroke.

The control device for a premixed compression self-ignition internal combustion engine according to the present invention is applied to the above-described premixed compression self-ignition internal combustion engine,
A self-ignition timing acquisition means for acquiring a self-ignition timing that is a timing at which the mixed gas self-ignites,
Until the self-ignition timing of the acquired current combustion cycle or the acquired current time so that the self-ignition timing of the next combustion cycle coincides with the maximum output auto-ignition timing that maximizes the torque output by the internal combustion engine The combustion gas supply amount is determined based on the average self-ignition timing that is the average value of the self-ignition timings of a plurality of predetermined combustion cycles, and the combustion gas generated in the previous combustion cycle is also determined. Combustion gas supply means for supplying as the combustion gas contained in the mixed gas in the next combustion cycle by the supply amount;
Is provided.

  According to this, the combustion gas supply amount is determined so that the self-ignition timing of the next combustion cycle coincides with the maximum output self-ignition timing, and the combustion gas of the determined combustion gas supply amount is compared with the next combustion cycle. Supplied. As a result, the actual self-ignition timing coincides with the maximum output self-ignition timing, so that the torque output by the internal combustion engine becomes the maximum among all self-ignition timings. As a result, the internal combustion engine can be operated with good fuel efficiency.

The control device for a premixed compression self-ignition internal combustion engine according to the present invention is applied to the above-described premixed compression self-ignition internal combustion engine,
Operating state acquisition means for acquiring the operating state of the internal combustion engine;
A self-ignition timing acquisition means for acquiring a self-ignition timing that is a timing at which the mixed gas self-ignites,
If the acquired operating state is a predetermined operating state, the auto-ignition timing of the next combustion cycle is advanced earlier than the maximum output auto-ignition timing that maximizes the torque output by the internal combustion engine. Combustion gas based on the average self-ignition timing which is the average value of the self-ignition timing of the plurality of predetermined combustion cycles up to the acquired current time or the acquired self-ignition timing of the current combustion cycle so as to coincide with the timing Combustion gas supply that determines the supply amount and supplies the combustion gas generated in the combustion cycle up to this time as the combustion gas contained in the mixed gas in the next combustion cycle by the determined combustion gas supply amount Means,
Is provided.

  According to this, when the acquired operation state is a predetermined operation state, the combustion gas supply amount is determined so that the self-ignition timing of the next combustion cycle matches the early self-ignition timing, and the determined combustion gas A supply of combustion gas is supplied for the next combustion cycle.

  As a result, the actual self-ignition timing matches the early self-ignition timing that is more advanced than the maximum output self-ignition timing, so the temperature of the mixed gas is the case where the actual self-ignition timing matches the maximum output self-ignition timing. The temperature necessary for self-ignition of the mixed gas (auto-ignition temperature) is reached earlier. As a result, for example, even in a predetermined operation state such as a low-load operation state where the mixed gas is difficult to self-ignite, the mixed gas can be self-ignited more reliably.

<First Embodiment>
Hereinafter, embodiments of a control device for a premixed compression self-ignition internal combustion engine according to the present invention will be described with reference to the drawings. The control device according to the first embodiment is applied to a multi-cylinder (in this example, four-cylinder) internal combustion engine that is operated by a four-cycle premixed compression auto-ignition system.

  The four-cycle premixed compression auto-ignition system has an intake stroke from the exhaust top dead center to the intake bottom dead center, a compression stroke from the intake bottom dead center to the compression top dead center, and an expansion from the compression top dead center to the expansion bottom dead center. This is an operation method in which four strokes consisting of a stroke and an exhaust stroke from an expansion bottom dead center to an exhaust top dead center are repeated each time the crank angle rotates 720 degrees.

  FIG. 2 shows a schematic configuration of a system in which the control device according to the first embodiment is applied to the internal combustion engine described above. FIG. 2 shows only a cross section of the specific cylinder, but the other cylinders have the same configuration.

  The internal combustion engine 10 supplies air to a cylinder block portion 20 including a cylinder block, a cylinder block lower case and an oil pan, a cylinder head portion 30 fixed on the cylinder block portion 20, and the cylinder block portion 20. And an exhaust system 50 for releasing the exhaust gas from the cylinder block 20 to the outside.

  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 cylinder 21 and the head of the piston 22 form a combustion chamber 25 together with the cylinder head portion 30.

  The cylinder head portion 30 communicates with an intake port 31 that communicates with the combustion chamber 25, an intake valve 32 that opens and closes the intake port 31, an intake valve drive mechanism 32 a that serves as an intake valve drive unit that drives the intake valve 32, and the combustion chamber 25. An exhaust port 33, an exhaust valve 34 for opening and closing the exhaust port 33, an exhaust valve driving mechanism 34a as an exhaust valve driving means for driving the exhaust valve 34, an ignition plug 35, and an ignition coil for generating a high voltage to be applied to the ignition plug 35 are included. An igniter 36, an injector (fuel injection valve) 37 for injecting fuel into the combustion chamber 25, a pressure accumulation chamber 37a for supplying high-pressure fuel to the injector 37, and a fuel pump 37b for pressure-feeding the fuel to the pressure accumulation chamber 37a are provided. The intake valve drive mechanism 32a and the exhaust valve drive mechanism 34a are connected to a drive circuit 38.

  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, an intake duct 43 that has one end connected to the surge tank 42 and forms an intake passage with the intake manifold 41 and the surge tank 42, An air filter (AF) 44, a mechanical supercharger (SC) 45, and a bypass flow rate adjustment valve (ABV) disposed in the intake duct 43 in order from the other end of the intake duct 43 to the downstream (surge tank 42). 46, an intercooler (IC) 47 and a throttle valve 48.

  The mechanical supercharger 45 includes a mechanical supercharger clutch 45a. The mechanical supercharger clutch 45a is responsive to the drive signal to mechanically drive the mechanical supercharger 45 by the internal combustion engine 10 (operating state, ie, supercharged state), and mechanical supercharger. The machine 45 is switched to a state where it is not driven by the internal combustion engine 10 (non-operating state, ie, non-supercharging state).

  The intercooler 47 is water-cooled and cools the air passing through the intake duct 43. The intercooler 47 is connected to a radiator 47a that releases heat of the cooling water in the intercooler 47 into the atmosphere, and a circulation pump 47b that circulates the cooling water between the intercooler 47 and the radiator 47a.

  The throttle valve 48 is rotatably supported by the intake duct 43, and is driven by a throttle valve actuator 48a so that the opening cross-sectional area of the intake duct 43 is variable.

The intake system 40 further includes a bypass passage 49.
One end of the bypass passage 49 is connected to the bypass flow rate adjustment valve 46, and the other end is connected to the intake duct 43 at a position between the intercooler 47 and the throttle valve 48. The bypass flow rate adjustment valve 46 changes the valve opening degree (not shown) in response to the drive signal, whereby the amount of air flowing into the intercooler 47 and the amount of air bypassing the intercooler 47 (the amount of air flowing into the bypass passage 49). ) And adjust.

  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, a crank position sensor 62, an in-cylinder pressure sensor 63 as an in-cylinder pressure detection means, an accelerator opening sensor 64, and an electric control device 70. The air flow meter 61 outputs a signal indicating the amount of air flowing through the intake duct 43. The crank position sensor 62 outputs a signal having a narrow pulse generated every time the crankshaft 24 rotates 1 ° and a wide pulse generated every time the crankshaft 24 rotates 360 °. . This signal represents the engine speed NE. The in-cylinder pressure sensor 63 outputs a signal representing the pressure (in-cylinder pressure) Pc in the combustion chamber 25. The in-cylinder pressure sensor 63 may be provided in the cylinder head portion 30 above the combustion chamber 25. The accelerator opening sensor 64 outputs a signal representing the operation amount (accelerator pedal operation amount) Accp of the accelerator pedal 65 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 (lookup 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 64, supplies signals from the sensors 61 to 64 to the CPU 71, and in accordance with instructions from the CPU 71, the igniter 36, the injector 37, the fuel pump 37b, the drive circuit 38, and the mechanical type. Drive signals are sent to the turbocharger clutch 45a, the bypass flow rate adjusting valve 46 and the throttle valve actuator 48a.

<Overview of operation>
Next, an outline of the operation of the control device configured as described above will be described. This control device opens the intake valve 32 so that a negative overlap period, which is a period in which both the intake valve 32 and the exhaust valve 34 are closed, is provided when shifting from the exhaust stroke to the intake stroke. Timing (intake valve opening timing) IO and exhaust valve 34 timing (exhaust valve closing timing) EC are determined.

  Further, the control device estimates (acquires) the self-ignition timing, which is the timing at which the mixed gas self-ignites, based on the output of the in-cylinder pressure sensor 63, and the estimated self-ignition timing (estimated self-ignition timing) Est advances. The intake valve opening timing IO and the exhaust valve closing timing EC determined for the next combustion cycle are corrected so that the negative overlap period in the next combustion cycle becomes longer as the angle increases.

  As a result, a larger amount of combustion gas is supplied to the next combustion cycle as the estimated self-ignition timing Sest advances, so even if the actual self-ignition timing varies, the fluctuation in the compression start temperature varies. Can be suppressed, and the magnitude of the fluctuation of the self-ignition timing with the progress of the combustion cycle can be reduced.

<Details of operation>
(Determination of control amount and control time)
More specifically, the CPU 71 determines the timing for controlling the intake valve 32 and the exhaust valve 34, the timing for controlling the injector 37, and the amount of fuel to be injected into the injector 37 shown in the flowchart of FIG. The control amount and control timing determination routine for performing the control is performed after the crank angle of the nth cylinder (n is 1, 2, 3, and 4) 45 ° after the compression top dead center of the nth cylinder (retard side). Each time the control amount determination crank angle (ATDC 45 °) coincides with the control amount determination crank angle (ATDC 45 °), it is executed exclusively for the nth cylinder.

  Therefore, when the crank angle of the nth cylinder matches the control amount determination crank angle, the CPU 71 starts processing from step 300 and proceeds to step 305, where the accelerator pedal operation amount Accp ( Engine load) and the engine speed NE detected by the crank position sensor 62 in step 310 are read.

  Then, the CPU 71 proceeds to step 315, the current accelerator pedal operation amount Accp and the engine rotational speed NE, the accelerator pedal operation amount Accp and the engine rotational speed NE, and the output shaft torque required for the internal combustion engine 10 (requested output shaft). The required output shaft torque TQ (= MapTQ (Accp, NE)) is determined based on the table MapTQ that defines the relationship with the torque (TQ). The required output shaft torque TQ and the engine rotational speed NE represent the operating state of the internal combustion engine 10.

In the following description, a table represented as 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 and the current variable b and the table MapX (a, b). It means that. Note that there may be only one variable or three or more variables.
Further, the execution of the processing of step 305, step 310, and step 315 corresponds to the achievement of the function of the operating state acquisition means.

  Next, the CPU 71 proceeds to step 320 to obtain the exhaust valve opening timing EO based on the table MapEO (TQ, NE). Here, the table MapEO is set in advance such that the required exhaust valve opening timing EO is a predetermined timing before the expansion bottom dead center (advance side). Here, the exhaust valve opening timing EO is represented by ATDC which is a crank angle with the compression top dead center (TDC) as the origin and the rotation direction of the crankshaft 24 as the positive direction. Hereinafter, in this specification, it is assumed that all timings are represented by ATDC.

  Then, the CPU 71 proceeds to step 325 to obtain the exhaust valve closing timing EC based on the table MapEC (TQ, NE). Here, the table MapEC is set in advance so that the required exhaust valve closing timing EC is a predetermined timing before the exhaust top dead center.

  Next, the CPU 71 proceeds to step 330 to obtain the intake valve opening timing IO based on the table MapIO (TQ, NE). Here, the table MapIO has an intake valve opening timing IO determined based on the table MapIO in an arbitrary operating state after the exhaust valve closing timing EC determined based on the table MapEC (retarded side). Is set in advance so as to be the predetermined timing.

  As will be described later, exhaust ends at the exhaust valve closing timing EC, and thereafter, intake starts at the intake valve opening timing IO after a predetermined period has elapsed. That is, the negative overlap period during which both the intake valve 32 and the exhaust valve 34 are closed when the exhaust stroke is shifted to the intake stroke is an exhaust valve closing timing EC as a start timing during the same period. And the intake valve opening timing IO as the end timing during the same period. In the present specification, the negative overlap period determined by the exhaust valve closing timing EC determined in the step 325 and the intake valve opening timing IO determined in the step 330 is expressed as follows. This is called the scheduled overlap period OLep.

  Subsequently, the CPU 71 proceeds to step 335 to obtain the intake valve closing timing IC based on the table MapIC (TQ, NE). Here, the table MapIC is set in advance so that the required intake valve closing timing IC is a predetermined timing immediately after the intake bottom dead center.

  Thereafter, the CPU 71 proceeds to step 340 to obtain the fuel injection amount τ based on the table Mapτ (TQ, NE). Here, the table Mapτ is set in advance so that the required output shaft torque TQ is output by the internal combustion engine 10 when the fuel of the required fuel injection amount τ burns at a predetermined timing.

  Next, the CPU 71 proceeds to step 345 to obtain the fuel injection start timing INJ based on the table MapINJ (TQ, NE). Here, in the table MapINJ, the fuel injection start timing INJ obtained based on the table MapINJ in an arbitrary operation state is a predetermined timing immediately after the intake valve opening timing IO obtained based on the table MapIO. Is set in advance. Accordingly, the required fuel injection start timing INJ is an initial timing within a period during which the intake valve 32 is open (intake valve opening period).

  Then, the CPU 71 proceeds to step 350 and reads from the RAM 73 the latest value of the self-ignition timing (estimated self-ignition timing) Est estimated by a self-ignition timing estimation routine described later.

  Next, the CPU 71 proceeds to step 355 to obtain the correction amount ΔEC of the exhaust valve closing timing EC based on the table MapΔEC (Sest, TQ, NE), and the correction amount ΔIO of the intake valve opening timing IO to the table MapΔIO ( Sest, TQ, NE).

  Here, as shown by the curve CEC in FIG. 4, the table MapΔEC is such that when the estimated self-ignition timing Set matches the planned self-ignition timing Sep, the required correction amount ΔEC is zero and the estimated self-ignition timing Sest is zero. It is set in advance so that the required correction amount ΔEC decreases as the ignition timing Sest advances. Here, the scheduled self-ignition timing Sep is determined by the internal combustion engine 10 to operate according to the control amount and the control timing determined by the processing from step 320 to step 345 based on the current requested output shaft torque TQ and the current engine speed NE. As a result, the timing when the mixed gas self-ignites is scheduled.

  Further, as shown by the curve CIO in FIG. 4, the table MapΔIO is such that when the estimated self-ignition timing Set matches the scheduled self-ignition timing Sep, the required correction amount ΔIO becomes 0 and the estimated self-ignition It is set in advance so that the required correction amount ΔIO increases as the timing Est advances.

  Next, the CPU 71 proceeds to step 360 and corrects the exhaust valve closing timing EC by adding the correction amount ΔEC determined in step 355 to the exhaust valve closing timing EC determined in step 325 ( Update. In step 360, the CPU 71 corrects (updates) the intake valve opening timing IO by adding the correction amount ΔIO determined in step 355 to the intake valve opening timing IO determined in step 330. )

  Thus, the exhaust valve closing timing EC is advanced and the intake valve opening timing IO is retarded as the estimated self-ignition timing Sest advances. Therefore, as shown in FIG. 5, the negative overlap period is set to become longer as the estimated self-ignition timing Sest advances. Furthermore, the negative overlap period is set to coincide with the scheduled overlap period OLep when the estimated self-ignition timing Sest matches the scheduled self-ignition timing Sep. Note that the execution of the processing of step 355 and step 360 corresponds to the achievement of part of the function of the combustion gas supply means.

  Then, the CPU 71 proceeds to step 399 to end the present routine tentatively. As described above, the timing for controlling the intake valve 32, the exhaust valve 34 and the injector 37 of the nth cylinder and the amount of fuel injected into the combustion chamber 25 of the nth cylinder are determined.

(Self-ignition timing estimation)
On the other hand, since the CPU 71 estimates the estimated auto-ignition timing Est used in the routine of FIG. 3, the CPU 71 performs the auto-ignition timing estimation routine shown in the flowchart of FIG. 6 every time the crank angle changes by a predetermined minute crank angle. In addition, the operation is performed exclusively for the nth cylinder. Note that the execution of the process of the self-ignition timing estimation routine corresponds to the achievement of the function of the self-ignition timing acquisition means.

  Therefore, when the predetermined timing comes, the CPU 71 starts processing from step 600 and proceeds to step 605 to read the in-cylinder pressure Pc detected by the in-cylinder pressure sensor 63 of the nth cylinder. Next, the CPU 71 proceeds to step 610, from the current in-cylinder pressure Pc read in step 605 to the past (previous execution) in-cylinder set in step 630, which will be described later, in the previous execution of this routine. A time change amount ΔPc (= Pc−Pc1) of the in-cylinder pressure is calculated by reducing the pressure Pc1.

  Then, the CPU 71 proceeds to step 615 and reads the crank angle θ detected by the crank position sensor 62. Thereafter, the CPU 71 proceeds to step 620 to store the time variation ΔPc of the in-cylinder pressure calculated at step 610 in the RAM 73 in association with the crank angle θ read at step 615.

Next, the CPU 71 proceeds to step 625 to determine whether or not the current crank angle of the nth cylinder matches the control amount determination crank angle.
First, the case where the current crank angle of the nth cylinder is the crank angle immediately after the control amount determination crank angle will be described. In this case, the CPU 71 determines “No” in step 625 and proceeds to step 630 to set the past in-cylinder pressure Pc1 to the current in-cylinder pressure Pc read in step 605. Then, the CPU 71 proceeds to step 699 to end the present routine tentatively.

  The above processing for this routine is repeatedly executed until the crank angle of the nth cylinder matches the control amount determination crank angle. During this time, every time this routine is executed, the time variation ΔPc of the in-cylinder pressure is associated with the crank angle θ and stored in the RAM 73.

  When the crank angle of the nth cylinder coincides with the control amount determination crank angle, when the CPU 71 executes this routine and proceeds to step 625, the CPU 71 determines “Yes” and proceeds to step 635, where the RAM 73 The maximum time variation ΔPc is retrieved from the time variation ΔPc of the in-cylinder pressure stored in.

  Then, the CPU 71 proceeds to step 640 and sets the estimated self-ignition timing Est to the crank angle θ corresponding to (stored in association with) the maximum time variation ΔPc searched in step 635. In other words, the CPU 71 estimates the crank angle θ corresponding to the maximum time variation ΔPc as the estimated self-ignition timing Sest. Further, the CPU 71 causes the RAM 73 to store the estimated self-ignition timing Est estimated in step 640.

  Thereafter, the CPU 71 proceeds to step 645 and clears (deletes or sets “0”) the time variation ΔPc stored in the RAM 73. Next, as described above, the CPU 71 proceeds to step 699 after executing the processing of step 630 and once ends this routine.

  In the present embodiment, the timing at which the time variation ΔPc of the in-cylinder pressure is maximized in one combustion cycle is estimated as the estimated self-ignition timing Sett, but the amount of heat generated by combustion (heat The rate at which the rate of change (the rate of heat generation) (heat generation rate) becomes maximum in one combustion cycle may be estimated as the estimated autoignition timing Sett. Further, a timing at which a ratio of a value obtained by integrating the heat generation amount in one combustion cycle to a total amount of heat generation amount in one combustion cycle becomes a predetermined ratio (for example, half) is estimated as the estimated self-ignition timing Set. It may be configured as follows.

(Drive control)
Further, the CPU 71 executes a drive control routine for controlling the drive of the internal combustion engine 10 shown in the flowchart of FIG. 7 exclusively for the nth cylinder every time the crank angle changes by a predetermined minute crank angle. ing.

  Accordingly, when the predetermined timing is reached, the CPU 71 starts processing of this routine from step 700 and proceeds to step 705, where the current crank angle of the nth cylinder is determined in step 320 of FIG. 3 described above. It is determined whether or not it coincides with the exhaust valve opening timing EO. If the current crank angle of the nth cylinder coincides with the exhaust valve opening timing EO of the nth cylinder, the CPU 71 makes a “Yes” determination at step 705 to proceed to step 710, where the exhaust valve drive mechanism An instruction signal is sent to 34a to open the exhaust valve 34 of the nth cylinder (see (1) in FIG. 8). Thereby, the combustion gas produced | generated by the combustion in the last combustion cycle begins to be discharged | emitted from the combustion chamber 25 (exhaust starts).

  Thereafter, according to the processing from step 715 to step 750, the CPU 71 generates various instruction signals at appropriate timing as in the case of opening the exhaust valve 34, and performs various operations described below.

  Step 715 and Step 720 ... When the current crank angle of the nth cylinder coincides with the exhaust valve closing timing EC of the nth cylinder corrected in step 360 of FIG. 3, an instruction signal is sent to the exhaust valve drive mechanism 34a. Then, the exhaust valve 34 of the nth cylinder is closed (see (2) in FIG. 8). Thereby, exhaust ends. As a result, a part of the combustion gas generated by the combustion of the mixed gas in the current combustion cycle remains in the combustion chamber 25 and is supplied to the next combustion cycle.

  Steps 725 and 730 ... When the current crank angle of the nth cylinder coincides with the intake valve opening timing IO of the nth cylinder corrected in step 360 of FIG. 3, an instruction signal is sent to the intake valve drive mechanism 32a. Then, the intake valve 32 of the nth cylinder is opened (see (3) in FIG. 8). Thereby, air begins to be introduced into the combustion chamber 25 (intake starts).

  By the way, when the start time or end time of the negative overlap period is changed, the next time the combustion gas generated by the combustion of the mixed gas in the current combustion cycle remains in the combustion chamber 25. The amount of combustion gas supplied to the combustion cycle and the amount of air newly supplied to the next combustion cycle change.

  As shown in FIG. 5, when the estimated self-ignition timing Sest is a timing S1 that is more advanced than the planned self-ignition timing Sep, the temperature of the combustion gas (residual combustion gas temperature) is the expected temperature (scheduled temperature). The temperature T1 is lower than Tep. In this case, as described above, the negative overlap period is set to the overlap period OL1 longer than the scheduled overlap period OLep. Therefore, the amount of combustion gas (combustion gas residual amount) that is generated by the combustion of the mixed gas in the current combustion cycle and is supplied to the next combustion cycle by remaining in the combustion chamber 25. ) Is a residual amount A1 which is larger than the planned residual amount of combustion gas (scheduled residual amount) Aep.

  As a result, even when the temperature of the combustion gas included in the mixed gas in the next combustion cycle becomes lower, the temperature of the mixed gas at the time of starting the compression of the mixed gas (the time of starting compression) is excessively higher than the planned temperature. It can prevent becoming low. As a result, it is possible to prevent the actual self-ignition timing in the next combustion cycle from being excessively retarded from the scheduled self-ignition timing Sep.

On the other hand, when the estimated self-ignition timing Sest is the timing S2 that is retarded from the planned self-ignition timing Sep, the residual combustion gas temperature is a temperature T2 that is higher than the planned temperature Tep. In this case, the negative overlap period is an overlap period OL2 shorter than the scheduled overlap period OLep. Therefore, the combustion gas residual amount becomes a residual amount A2 smaller than the planned residual amount Aep. Thereby, even if the temperature of the combustion gas included in the mixed gas in the next combustion cycle increases, it is possible to prevent the temperature of the mixed gas at the start of compression from becoming excessively higher than the planned temperature. As a result, it is possible to prevent the actual self-ignition timing in the next combustion cycle from being advanced excessively than the scheduled self-ignition timing Sep.
Note that the execution of each processing from step 715 to step 730 corresponds to the achievement of part of the function of the combustion gas supply means.

  Step 735 and Step 740: When the current crank angle of the nth cylinder coincides with the fuel injection start timing INJ of the nth cylinder determined in step 345 of FIG. 3, the nth cylinder injector 37 is changed to the step of FIG. The valve is opened for a time corresponding to the fuel injection amount τ determined at 340, and fuel of the fuel injection amount τ is injected into the combustion chamber 25 (see (4) in FIG. 8). The injected fuel is diffused in the combustion chamber 25 by the flow of air subsequently sucked into the combustion chamber 25.

  Step 745 and Step 750: When the current crank angle of the nth cylinder coincides with the intake valve closing timing IC of the nth cylinder determined in step 335 of FIG. 3, an instruction signal is sent to the intake valve drive mechanism 32a. Then, the intake valve 32 of the nth cylinder is closed (see (5) in FIG. 8). As a result, the intake gas is finished and the compression of the mixed gas composed of air, fuel, and combustion gas is started.

Thereafter, when the piston 22 reaches the vicinity of the top dead center position, the temperature of the mixed gas compressed by the piston 22 reaches the self-ignition temperature. Thereby, the mixed gas starts combustion by self-ignition.
Then, the CPU proceeds to step 799 to end this routine once.
In this way, the internal combustion engine 10 is operated by a four-cycle premixed compression self-ignition system.

  As described above, according to the first embodiment of the control device for the premixed compression self-ignition internal combustion engine according to the present invention, the estimated auto-ignition timing Set in the current combustion cycle is advanced (that is, the current auto-ignition timing Set is advanced). A larger amount of combustion gas is supplied to the next combustion cycle (the lower the temperature of the combustion gas at the end of the combustion cycle).

  As a result, when the self-ignition timing of the current combustion cycle is advanced by a relatively large degree, that is, when the temperature of the combustion gas at the end of the current combustion cycle is lower than the expected temperature, there are relatively many cases. An amount of combustion gas is included in the gas mixture for the next combustion cycle. As a result, it is possible to prevent the compression start temperature from becoming excessively low, thereby preventing the autoignition timing of the next combustion cycle from being excessively retarded.

  On the other hand, if the self-ignition timing of the current combustion cycle is retarded by a relatively large amount, that is, if the temperature of the combustion gas at the end of the current combustion cycle is higher than the expected temperature, a relatively small amount Are included in the gas mixture of the next combustion cycle. Thereby, since it can prevent that compression start temperature becomes high too much, it can prevent that the self-ignition timing of the next combustion cycle advances too much.

  Therefore, according to the present invention, the amount of fluctuation of the self-ignition timing with the progress of the combustion cycle is determined so that a constant amount of combustion gas is supplied to the next combustion cycle regardless of the self-ignition timing of the current combustion cycle. It can be made smaller compared to the case. In other words, it is possible to prevent the state where the output shaft torque fluctuates relatively large from continuing.

Second Embodiment
Next, a control device for a premixed compression self-ignition internal combustion engine according to a second embodiment of the present invention will be described. In the control device according to the second embodiment, the learning value GEC ^* is set so that the average self-ignition timing Save ^*, which is the average value of the estimated self-ignition timings Set, coincides with the target self-ignition timing Stgt according to the operating state of the internal combustion engine 10 ^. And GIO ^* are respectively calculated, and the control device according to the first embodiment is different only in that the negative overlap period is corrected based on the calculated learning values GEC ^* and GIO ^* . Hereinafter, this difference will be mainly described.

  This control device executes a routine in place of the routine of FIG. 3 as a routine for determining the control amount and the control timing. This routine is a routine in which the processing from step 905 to step 950 shown by the flowchart in FIG. 9 is added between step 350 and step 399 of the routine shown in FIG. 3 according to the first embodiment. Note that the execution of each processing from step 905 to step 950 corresponds to the achievement of part of the function of the combustion gas supply means.

First, the case where the actual self-ignition timing is substantially constant (the magnitude of fluctuation of the actual self-ignition timing is extremely small) will be described. In this case, when the CPU 71 starts the processing of this routine and executes the processing up to step 350, the CPU 71 proceeds to step 905, and average autoignition calculated in step 910, which will be described later, at the previous execution of this routine. It is determined whether or not the magnitude of the difference between the timing Save ^* and the estimated auto-ignition timing Test read in step 350 is smaller than a predetermined threshold value α. Here, the threshold value α is a positive value, and may vary according to the operating state of the internal combustion engine 10.

According to the above assumption, the estimated self-ignition timing Sest is very close to the average self-ignition timing Save ^* . Therefore, the CPU 71 makes a “Yes” determination at step 905 to proceed to step 910 and read the average autoignition timing Save ^* calculated at step 910 at the time of the previous execution of this routine and the above step 350. The latest average self-ignition timing Save ^* is calculated based on the estimated self-ignition timing Sest and the formula shown in step 910. Here, the variable with the superscript “*” is a variable independent of each other for each predetermined range of the required output shaft torque TQ and the engine speed NE.

Further, the CPU 71 adds “1” to the average basic cycle number N ^* , which is the number of the estimated self-ignition timing Sest that is the basis for calculating the average self-ignition timing Save ^* in Step 910.

  Then, the CPU 71 proceeds to step 915 to obtain the target self-ignition timing Stgt based on the table MapStgt (TQ, NE). Here, as shown in FIG. 10, the table MapStgt is a region in which the required output shaft torque TQ is smaller than a predetermined low torque threshold and the engine speed NE is lower than a predetermined high rotation threshold (internal combustion engine). In the region (A) where the operation state of 10 is a low load operation state on the low load side from the low load threshold) A, the desired target autoignition timing Stgt is the early autoignition timing and higher torque side than the same region A Alternatively, in the high rotation side region (region in which the operation state of the internal combustion engine 10 is in the middle and high load operation state on the higher load side than the low load threshold) B, the required target ignition timing Stgt is the maximum output ignition timing. It is set to be.

  The maximum output self-ignition timing is a timing at which the output shaft torque output from the internal combustion engine 10 is maximized, as shown in FIG. 11 showing the change of the output shaft torque with respect to the self-ignition timing S. Further, the early self-ignition timing is a timing on the advance side with respect to the maximum output self-ignition timing.

  Next, the CPU 71 proceeds to step 920 to obtain the learning value correction coefficient KEC based on the table MapKEC (TQ, NE) and obtain the learning value correction coefficient KIO based on the table MapKIO (TQ, NE). Here, the table MapKEC is set so that the obtained learning value correction coefficient KEC is a negative value. The table MapKIO is set so that the obtained learning value correction coefficient KIO is a positive value.

Thereafter, the CPU 71 proceeds to step 925, and subtracts the target self-ignition timing Stgt determined in step 915 from the latest average auto-ignition timing Save ^* calculated in step 910, in the step 920. A correction value for the learning value GEC ^* is calculated by multiplying the calculated learning value correction coefficient KEC, and the calculated correction value is used as the learning value GEC ^* calculated in step 925 at the previous execution of this routine ^. Is added to the latest learning value GEC ^* .

Thus, when the average self-ignition timing Save ^* is on the advance side of the target self-ignition timing Stgt, the value Save ^* -Stgt is a negative value, and the correction value for the learning value GEC ^* is a positive value. The learning value GEC ^* increases. As a result, the exhaust valve closing timing EC is corrected to the retard side in step 935 described later. That is, the exhaust valve closing timing EC is corrected so that the negative overlap period becomes shorter.

Further, the CPU 71 sets the value obtained by subtracting the target self-ignition timing Stgt determined in step 915 from the latest average self-ignition timing Save ^* calculated in step 910 in step 925 to step 920. The correction value for the learning value GIO ^* is calculated by multiplying the learning value correction coefficient KIO obtained in this way, and the calculated correction value is added to the learning value GIO ^* calculated by the previous execution of the processing of step 925. Thus, the latest learning value GIO ^* is calculated.

As a result, when the average self-ignition timing Save ^* is on the more advanced side than the target self-ignition timing Stgt, the value Save ^* -Stgt is negative and the correction value for the learning value GIO ^* is negative. The learning value GIO ^* decreases. As a result, the intake valve opening timing IO is corrected to the more advanced side in step 935 described later. That is, the intake valve opening timing IO is corrected so that the negative overlap period becomes shorter.

  Then, the CPU 71 proceeds to step 930 and sets the values of the correction amounts ΔEC and ΔIO to “0”.

Next, the CPU 71 proceeds to step 935 and uses the learning value GEC ^* calculated in step 925 and the correction amount ΔEC set in step 930 at the exhaust valve closing timing EC determined in step 325. In addition, the exhaust valve closing timing EC is corrected (updated). Further, the CPU 71 sets the learning value GIO ^* calculated in step 925 to the intake valve opening timing IO determined in step 330 in step 935 and the correction amount ΔIO set in step 930. To correct (update) the intake valve opening timing IO.
Then, the CPU 71 proceeds to step 399 to end the present routine tentatively.

Thus, when the average self-ignition timing Save ^* is on the advance side of the target self-ignition timing Stgt, the learning values GEC ^* and GIO ^* are updated so that the negative overlap period is shorter. As a result, the amount of combustion gas supplied to the next combustion cycle is reduced, so that the compression start temperature in the next combustion cycle is lowered. As a result, in the next combustion cycle, the actual self-ignition timing is retarded and sufficiently close to the target self-ignition timing Stgt.

On the other hand, when the average self-ignition timing Save ^* is on the retard side with respect to the target self-ignition timing Stgt, the learning values GEC ^* and GIO ^* are updated so that the negative overlap period becomes longer. As a result, the amount of combustion gas supplied to the next combustion cycle increases, so that the compression start temperature in the next combustion cycle increases. As a result, in the next combustion cycle, the actual self-ignition timing is advanced and sufficiently close to the target self-ignition timing Stgt.

  As described above, the actual self-ignition timing can be matched with the target self-ignition timing Stgt. As a result, when the operation state of the internal combustion engine 10 is a medium-high load operation state (in the region B of FIG. 10), the target self-ignition timing Stgt is set to the maximum output self-ignition timing and the actual self-ignition timing is The maximum output self-ignition timing can be matched. Further, when the operation state of the internal combustion engine 10 is a low load operation state (in the region A of FIG. 10), the target self-ignition timing Stgt is set to the early self-ignition timing, and the actual self-ignition timing is set to the early self-ignition timing. It is made to coincide with the self-ignition timing.

  Next, the description continues when the actual self-ignition timing fluctuation is relatively large. When the CPU 71 proceeds to step 905, it determines “No” in step 905 and proceeds to step 950. As in step 355, the correction amount ΔEC of the exhaust valve closing timing EC and the correction amount ΔIO of the intake valve opening timing IO are determined, and then the routine proceeds to step 935, where the exhaust valve closing timing EC and the intake valve opening timing are reached. Correct IO.

As described above, when the magnitude of the fluctuation of the actual self-ignition timing is relatively large, the magnitude of the fluctuation of the compression start temperature accompanying the fluctuation of the temperature of the combustion gas is suppressed as in the first embodiment. Negative overlap period is corrected.
As a result, the magnitude of the fluctuation of the self-ignition timing with the progress of the combustion cycle is compared with the case where a certain amount of combustion gas is supplied to the next combustion cycle regardless of the self-ignition timing of the current combustion cycle. Can be made smaller. In other words, it is possible to prevent the state where the output shaft torque fluctuates relatively large from continuing.

As described above, according to the second embodiment of the control device for the premixed compression self-ignition internal combustion engine according to the present invention, when the actual self-ignition timing is substantially constant, the actual self-ignition timing is the target self-ignition timing. The learning values GEC ^* and GIO ^* are calculated so as to coincide with the ignition timing Stgt, and the exhaust valve closing timing EC and the intake valve opening timing IO are corrected based on the calculated learning values GEC ^* and GIO ^* . As a result, the actual self-ignition timing coincides with the target self-ignition timing Stgt.

  By the way, in the second embodiment, when the operation state of the internal combustion engine 10 is a medium / high load operation state (during medium / high load operation), the maximum output timing is adopted as the target self-ignition timing Stgt. When the operation state is the low load operation state (during low load operation), the early self-ignition timing is adopted as the target self-ignition timing Stgt.

  Therefore, the negative overlap period is corrected so that the actual self-ignition timing coincides with the maximum output self-ignition timing during the medium and high load operation. As a result, the actual self-ignition timing coincides with the maximum output self-ignition timing, so that the torque output by the internal combustion engine 10 becomes the maximum among all self-ignition timings. As a result, the internal combustion engine 10 can be operated with good fuel efficiency.

  On the other hand, during low load operation, the negative overlap period is corrected so that the actual self-ignition timing matches the early self-ignition timing. As a result, the actual self-ignition timing matches the early self-ignition timing that is more advanced than the maximum output self-ignition timing, so the temperature of the mixed gas is the case where the actual self-ignition timing matches the maximum output self-ignition timing. The temperature necessary for self-ignition of the mixed gas (auto-ignition temperature) is reached earlier. As a result, the mixed gas can be self-ignited more reliably during low-load operation where the mixed gas is less likely to self-ignite.

  In the operating range where the “change in the temperature of the combustion gas supplied to the next combustion cycle” relative to the “change in autoignition timing in the current combustion cycle” is relatively small, the control amount and the control timing are determined. In this routine, step 950 may be omitted.

In the second embodiment, the average auto-ignition timing Save ^* is the average value of the estimated auto-ignition timings Est of all the combustion cycles up to the present time, but only a predetermined number of cycles (for example, three). The average value of the estimated self-ignition timing Sest from the previous combustion cycle to the current combustion cycle may be used.

Further, the second embodiment calculates an average auto-ignition timing Save ^* that is an average value of the estimated auto-ignition timings Est of the combustion cycle up to the present time, and the difference between the average auto-ignition timing Save ^* and the target auto-ignition timing Stgt. The learning values GEC ^* and GIO ^* are calculated based on the learning values GEC ^* and GIO ^* based on the difference between the estimated self-ignition timing Sest and the target self-ignition timing Stgt of the current combustion cycle ^. May be configured to calculate. In this case, in the routine for determining the control amount and the control timing, the processing of step 910 is omitted, and the average auto-ignition timing Save ^* of the same equation is used as the estimated auto-ignition timing Set instead of the equation shown in step 925. Learning values GEC ^* and GIO ^* are calculated by the replaced formula.

  The present invention is not limited to the above embodiments and modifications, and various modifications can be employed within the scope of the present invention. For example, in each of the above embodiments, the operating system of the internal combustion engine 10 is a 4-cycle system, but it may be a 2-cycle system. In this case, it is preferable to change the amount of combustion gas supplied to the next combustion cycle by correcting the scavenging period by correcting the exhaust valve closing timing EC and the intake valve opening timing IO.

  Further, in each of the above embodiments, the combustion gas is supplied into the combustion chamber 25 by providing a negative overlap period, and the amount of combustion gas remaining in the combustion chamber 25 is controlled by changing the negative overlap period. However, the combustion gas is supplied into the combustion chamber 25 by introducing the combustion gas from the exhaust passage to the intake passage via the circulation passage that connects the exhaust passage and the intake passage, and is disposed in the circulation passage. The amount of combustion gas supplied into the combustion chamber 25 may be controlled by controlling the amount of combustion gas flowing through the same circulation passage by the control valve.

Alternatively, the combustion gas once exhausted to the exhaust port 33 may be re-inhaled into the combustion chamber 25 by reopening the exhaust valve closed at the end of exhaust in the intake stroke. In this case, the amount of combustion gas supplied into the combustion chamber 25 is controlled by changing the opening timing and closing timing of the exhaust valve in the intake stroke.
Further, in each of the above embodiments, a spark may be supplementarily generated by the spark plug 35 in order to reliably prevent misfire.

It is the graph which showed the change of the self-ignition timing with respect to a combustion cycle, and combustion gas temperature. 1 is a schematic configuration diagram of a system in which a control device according to a first embodiment of the present invention is applied to a four-cycle premixed compression self-ignition internal combustion engine. FIG. 3 is a flowchart showing a routine for determining a control amount and a control timing executed by a CPU shown in FIG. 2. FIG. It is the figure which showed the table which prescribed | regulated the relationship between the estimated self-ignition timing which the CPU shown in FIG. 2 refers, and a correction amount. It is the graph which showed the change of the residual combustion gas temperature with respect to presumed self-ignition timing, the negative overlap period, and the combustion gas residual amount. 3 is a flowchart showing a routine for estimating self-ignition timing executed by a CPU shown in FIG. 2. FIG. 3 is a flowchart showing a routine for driving and controlling an internal combustion engine executed by a CPU shown in FIG. 2. FIG. FIG. 3 is an explanatory diagram conceptually showing intake valve opening timing, intake valve closing timing, exhaust valve opening timing, exhaust valve closing timing, fuel injection start timing, and the like. It is a flowchart showing the process performed in addition to the routine shown in FIG. 3 in order for the control apparatus which concerns on 2nd Embodiment of this invention to determine a control amount and control time. It is the figure which showed the table which prescribed | regulated the relationship between the request | requirement output shaft torque and engine rotation speed which are referred by the control apparatus which concerns on 2nd Embodiment of this invention, and target self-ignition timing. It is the graph which showed the change of the output shaft torque to self-ignition timing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 31 ... Intake port, 32 ... Intake valve, 32a ... Intake valve drive mechanism, 33 ... Exhaust port, 34 ... Exhaust valve, 34a ... Exhaust valve drive mechanism, 37 ... Injector, 38 ... Drive circuit, 62 ... Crank position sensor, 63 ... In-cylinder pressure sensor, 64 ... Accelerator opening sensor, 65 ... Accelerator pedal, 70 ... Electric control device, 71 ... CPU, 73 ... RAM.

Claims (3)

A mixed gas containing air, fuel, and combustion gas is formed in the combustion chamber, and the formed mixed gas is compressed by the compression operation of the piston and burned by self-ignition, and then premixed compression A control device for an ignition internal combustion engine,
A self-ignition timing acquisition means for acquiring a self-ignition timing that is a timing at which the mixed gas self-ignites,
Generated in the previous combustion cycle so that the earlier the self-ignition timing in the current combustion cycle acquired by the self-ignition timing acquisition means, the greater the amount of combustion gas contained in the mixed gas in the next combustion cycle Combustion gas supply means for supplying the generated combustion gas to the mixed gas in the next combustion cycle ;
A control device for a premixed compression self-ignition internal combustion engine. A mixed gas containing air, fuel, and combustion gas is formed in the combustion chamber, and the formed mixed gas is compressed by the compression operation of the piston and burned by self-ignition, and then premixed compression A control device for an ignition internal combustion engine,
A self-ignition timing acquisition means for acquiring a self-ignition timing that is a timing at which the mixed gas self-ignites,
Until the self-ignition timing of the acquired current combustion cycle or the acquired current time so that the self-ignition timing of the next combustion cycle coincides with the maximum output auto-ignition timing that maximizes the torque output by the internal combustion engine The combustion gas supply amount is determined based on the average self-ignition timing that is the average value of the self-ignition timings of a plurality of predetermined combustion cycles, and the combustion gas generated in the previous combustion cycle is also determined. Combustion gas supply means for supplying as the combustion gas contained in the mixed gas in the next combustion cycle by the supply amount;
A control device for a premixed compression self-ignition internal combustion engine. A mixed gas containing air, fuel, and combustion gas is formed in the combustion chamber, and the formed mixed gas is compressed by the compression operation of the piston and burned by self-ignition, and then premixed compression A control device for an ignition internal combustion engine,
Operating state acquisition means for acquiring the operating state of the internal combustion engine;
A self-ignition timing acquisition means for acquiring a self-ignition timing that is a timing at which the mixed gas self-ignites,
If the acquired operating state is a predetermined operating state, the auto-ignition timing of the next combustion cycle is advanced earlier than the maximum output auto-ignition timing that maximizes the torque output by the internal combustion engine. Combustion gas based on the average self-ignition timing which is the average value of the self-ignition timing of the plurality of predetermined combustion cycles up to the acquired current time or the acquired self-ignition timing of the current combustion cycle so as to coincide with the timing Combustion gas supply that determines the supply amount and supplies the combustion gas generated in the combustion cycle up to this time as the combustion gas contained in the mixed gas in the next combustion cycle by the determined combustion gas supply amount Means,
A control device for a premixed compression self-ignition internal combustion engine.

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