JP2007231845A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine controlling an amount of soot discharged from a combustion chamber to a proper value, by using an in-cylinder soot concentration sensor. <P>SOLUTION: In this device, a peak value Y and a final value X are specified from history of in-cylinder soot concentration which is detected by the in-cylinder concentration sensor and is stored. When a value X/Y indicating a characteristic of a change pattern of the in-cylinder soot concentration is smaller than a final value/maximum value (=XTA/YTA) corresponding to a stationary adaptive pattern, it is determined that soot-generating reaction is excessive, so that a pilot interval is elongated to suppress the Soot-generation reaction. On the other hand, the value X/Y is larger than the value XTA/YTA, it is determined that oxidation reaction of the soot is insufficient, so that an EGR rate is reduced to promote the oxidation reaction of the soot. Therefore, even in a transient operation state, the change pattern of the in-cylinder concentration can be immediately adjusted to come close to the steady adaptive pattern. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to an apparatus for controlling the amount of soot (soot, carbon particulates) generated due to a fuel reaction in a combustion chamber.

  One of the main components constituting particulate matter (particulate, particulate matter, PM), which is one of the harmful substances discharged from the combustion chamber of internal combustion engines (particularly diesel engines), is made of carbon or the like. Soot. Therefore, it is very important to control the amount of soot discharged from the combustion chamber to an appropriate value.

Therefore, conventionally, the amount of soot discharged from the combustion chamber based on the amount of soot detected using an optical sensor (so-called smoke meter, opacimeter) provided to face the combustion chamber is appropriately set. A technique for controlling the value is widely known (for example, see Patent Document 1).
JP-A-9-96606

  However, the optical sensor (smoke meter, opacimeter) described above has poor responsiveness. For this reason, in the transient operation state, there is a delay in the change in the detected amount of generated soot, and as a result, there is a problem that the amount of soot discharged from the combustion chamber cannot be controlled to an appropriate value.

  Incidentally, in-cylinder soot concentration sensors that can directly detect the concentration of soot generated in the combustion chamber (hereinafter referred to as “in-cylinder soot concentration”) have been developed. The present inventor has found a technique for controlling the amount of soot discharged from the combustion chamber to an appropriate value using the in-cylinder soot concentration sensor even in a transient operation state.

  That is, an object of the present invention is to provide a control device for an internal combustion engine that can control the amount of soot discharged from a combustion chamber to an appropriate value even in a transient operation state by using an in-cylinder soot concentration sensor. There is to do.

  In the reaction process in which soot is generated in the combustion chamber, first, the soot generation reaction mainly occurs and the in-cylinder soot concentration increases, and then the generated soot oxidation reaction mainly occurs and the in-cylinder soot concentration decreases. It is known to go. That is, within a predetermined period including the combustion stroke, the in-cylinder soot concentration changes with a change pattern that first increases and then decreases.

  On the other hand, the degree of soot generation reaction can be adjusted by controlling the pilot interval (period from pilot injection to main injection), swirl, etc., and the degree of soot oxidation reaction can be adjusted by adjusting the EGR rate etc. can do. In other words, by controlling the control parameters of the internal combustion engine, the change pattern of the in-cylinder soot concentration within a predetermined period including the combustion stroke can be adjusted. As a result, the soot of the soot discharged from the combustion chamber can be adjusted. The amount can be adjusted.

  In addition, by using the in-cylinder soot concentration sensor, a change pattern of the in-cylinder soot concentration corresponding to a case where the amount of soot discharged from the combustion chamber becomes an appropriate value (hereinafter referred to as a “reference pattern”). Can be acquired in advance corresponding to various operating states (for example, fuel injection amount, engine speed, etc.).

  From the above, the control pattern of the internal combustion engine is controlled based on the change pattern of the in-cylinder soot concentration acquired by the in-cylinder soot concentration sensor so that the change pattern of the in-cylinder soot concentration becomes the reference pattern. It is possible to adjust the amount of soot discharged from the combustion chamber to an appropriate value. The present invention is based on such a principle.

  That is, the control device according to the present invention is applied to an internal combustion engine including an in-cylinder soot concentration sensor that directly detects an in-cylinder soot concentration that is a concentration of soot in the combustion chamber of the internal combustion engine, and a predetermined period including a combustion stroke. Storage means for storing a history of the detected in-cylinder soot concentration in the engine, and the internal combustion engine for controlling the amount of soot discharged from the combustion chamber based on the stored history of the in-cylinder soot concentration. Control means for controlling engine control parameters.

  More specifically, the control means is based on the in-cylinder soot concentration history so that a change pattern of the in-cylinder soot concentration obtained from the stored in-cylinder soot concentration history becomes a reference pattern. And controlling the control parameters of the internal combustion engine. According to this, even in the transient operation state, the change pattern of the in-cylinder soot concentration can be immediately adjusted so as to become the reference pattern, and as a result, the amount of soot discharged from the combustion chamber is set to an appropriate value. Can be adjusted.

  Here, the predetermined period is, for example, from the vicinity of the start time of the reaction related to the soot to the vicinity of the end time, and more specifically, from the fuel injection start timing to the exhaust valve opening timing, etc. It is. Further, as described above, the control parameter is, for example, a pilot interval, a swirl, an EGR rate, and the like, and the reference pattern is an operating state of the internal combustion engine at the present time (for example, a fuel injection amount, an engine rotation speed, etc.) 6 is a change pattern of the in-cylinder soot concentration acquired in advance corresponding to the case where the amount of soot discharged from the combustion chamber becomes an appropriate value.

  In the control device according to the present invention, the control means at a first time point that is a value representing a degree of soot generation reaction in the combustion chamber in the stored history of the in-cylinder soot concentration. The internal combustion engine based on the in-cylinder soot concentration and the in-cylinder soot concentration at a second time point after the first time point, which is a value representing the degree of oxidation reaction of soot generated in the combustion chamber. Preferably, the control parameter is configured to be controlled.

  As described above, the change pattern of the in-cylinder soot concentration is determined largely depending on the degree of soot generation reaction and the degree of oxidation reaction in the combustion chamber. Therefore, among the stored history of the in-cylinder soot concentration, the “in-cylinder soot concentration at the first time point” that is a value representing the degree of soot generation reaction in the combustion chamber, and the soot generated in the combustion chamber The characteristic (characteristic) of the change pattern of the in-cylinder soot concentration can be obtained to some extent accurately from only two values of “in-cylinder soot concentration at the second time point”, which is a value representing the degree of the oxidation reaction of it can.

  The above configuration is based on this viewpoint. According to this, in the stored in-cylinder soot concentration history, the two values of the above-mentioned “in-cylinder soot concentration at the first time point” and the above-mentioned “in-cylinder soot concentration at the second time point” are described. By controlling the control parameter using only the in-cylinder soot density change pattern can be adjusted to be a reference pattern.

  Here, the degree of soot generation reaction in the combustion chamber is considered to largely depend on the maximum value of the stored history of in-cylinder soot concentration, and the degree of soot oxidation reaction generated in the combustion chamber is: It is considered that it largely depends on the convergence value of the in-cylinder soot concentration that decreases after taking the maximum value. Therefore, as the first time point, the time point corresponding to the maximum value in the stored in-cylinder soot concentration history is used, and after the time point when the in-cylinder soot concentration is determined to have converged as the second time point. It is preferred to be configured to use

  Examples of the “time point after the time point when it is determined that the in-cylinder soot concentration has converged to a certain value” include, for example, the opening time of the exhaust valve, the change rate (absolute value) of the in-cylinder soot concentration being a predetermined minute value For example, when the gas temperature in the combustion chamber becomes equal to or lower than a predetermined temperature at which the reaction related to the soot substantially ends.

  More specifically, the control means represents a characteristic of a change pattern of the in-cylinder soot concentration based on the in-cylinder soot concentration at the first time point and the in-cylinder soot concentration at the second time point. It is preferable that a characteristic index value that is a value is acquired and a control parameter of the internal combustion engine is controlled based on the characteristic index value. Examples of the characteristic index value include a ratio of the in-cylinder soot concentration at the second time point to the in-cylinder soot concentration at the first time point.

  As described above, when the ratio of the in-cylinder soot concentration at the second time point to the in-cylinder soot concentration at the first time point is used as the characteristic index value, the control unit is configured to determine that the ratio is It is preferable that the control parameter is configured to be controlled in order to suppress the soot generation reaction when the value is smaller than a predetermined value corresponding to the reference pattern. In this case, specifically, for example, the pilot interval, which is a period from the pilot injection to the main injection, is controlled to be long.

  If the ratio is smaller than a predetermined value corresponding to the reference pattern, it may mean that the soot generation reaction is excessive as compared with the reference pattern. Therefore, according to the above configuration, when the soot generation reaction is excessive, the soot generation reaction can be suppressed, and as a result, the change pattern of the in-cylinder soot concentration can be adjusted to be the reference pattern.

  On the other hand, it is preferable that the control means is configured to control the control parameter in order to promote the oxidation reaction of Soot when the ratio is not less than a predetermined value corresponding to the reference pattern. In this case, specifically, for example, the EGR rate is controlled to be small.

  That the ratio is equal to or greater than a predetermined value corresponding to the reference pattern may mean that the oxidation reaction of the generated Soot is insufficient compared to the reference pattern. Therefore, according to the above configuration, when the soot oxidation reaction is insufficient, the soot oxidation reaction can be promoted, and as a result, the change pattern of the in-cylinder soot concentration can be adjusted to be a reference pattern. .

  Since the reference pattern changes depending on the operating state (fuel injection amount, engine speed, etc.), the predetermined value corresponding to the reference pattern is also changed according to the operating state (fuel injection amount, engine speed, etc.). It is preferable to be configured as described above.

  In the control device according to the present invention, the control means is configured so that the in-cylinder soot concentration at a time point after the time point when the in-cylinder soot concentration is determined to have converged (for example, the second time point) is the same point. It is preferable that the control parameter is not controlled when the value is equal to or less than the value corresponding to the reference pattern.

  When the in-cylinder soot concentration after the time when it is determined that the in-cylinder soot concentration has converged is equal to or less than the value corresponding to the reference pattern at the same time, the amount of soot discharged from the combustion chamber is the reference pattern. Or less than the appropriate value corresponding to. Therefore, in this case, it can be considered that it is not necessary to control the control parameter to adjust the change pattern of the in-cylinder soot density. The above configuration is based on such knowledge. According to this, it is possible to suppress unnecessary control parameter control.

  Alternatively, the control means increases the EGR rate when the in-cylinder soot concentration after the time when it is determined that the in-cylinder soot concentration has converged is equal to or less than a value corresponding to the reference pattern at the same point. It may be configured to.

  The generation amount of Soot (accordingly, PM) and the generation amount of NOx are in a relationship in which one increases and the other decreases. Therefore, when the amount of soot discharged from the combustion chamber is equal to or less than the appropriate value corresponding to the reference pattern, it can be considered that there is room for increasing the amount of soot to reduce the amount of NOx.

  The above configuration is based on this viewpoint. According to this, by increasing the EGR rate, the amount of soot can be increased and the amount of NOx can be decreased. As a result, the amount of soot discharged from the combustion chamber is less than or equal to the appropriate value (or It is possible to reduce the amount of NOx discharged from the combustion chamber while keeping it close to the vicinity.

  Hereinafter, an embodiment of a control device (a soot discharge amount control device) for an internal combustion engine (diesel engine) according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration of an entire system in which a control device for an internal combustion engine according to an embodiment of the present invention is applied to a four-cylinder internal combustion engine (diesel engine) 10. This system includes an engine main body 20 including a fuel supply system, an intake system 30 for introducing gas into a combustion chamber (in a cylinder) of each cylinder of the engine main body 20, and an exhaust system for discharging exhaust gas from the engine main body 20. 40, an EGR device 50 for performing exhaust gas recirculation, and an electric control device 60.

  A fuel injection valve (injection valve, injector) 21 is disposed above each cylinder of the engine body 20. Each fuel injection valve 21 is connected to a fuel injection pump 22 connected to a fuel tank (not shown) via a fuel pipe 23. The fuel injection pump 22 is electrically connected to the electric control device 60, and an actual fuel injection pressure (discharge) according to a drive signal (command signal corresponding to a fuel injection pressure Pcr described later) from the electric control device 60. The pressure of the fuel is increased so that the pressure) becomes the fuel injection pressure Pcr.

  As a result, the fuel injection valve 21 is supplied with fuel whose pressure has been increased from the fuel injection pump 22 to the fuel injection pressure Pcr. Further, the fuel injection valve 21 is electrically connected to the electric control device 60, and the drive signals from the electric control device 60 (command pilot fuel injection amount (mass) Qp, command main fuel injection amount (mass) Qm). The valve is opened by a command signal corresponding to Thus, the fuel whose pressure has been increased to the fuel injection pressure Pcr is directly injected into the combustion chamber first by the command pilot fuel injection amount Qp, and then main injection by the command main fuel injection amount Qm. It has become.

  The intake system 30 includes an intake manifold 31 connected to a combustion chamber of each cylinder of the engine body 20, an intake pipe 32 connected to an upstream side assembly of the intake manifold 31 and constituting an intake passage together with the intake manifold 31, an intake pipe A throttle valve 33 rotatably held in the throttle 32, a throttle valve actuator 33a for rotating the throttle valve 33 in response to a drive signal from the electric control device 60, and an intake pipe 32 upstream of the throttle valve 33. The mounted intercooler 34, the compressor 35a of the supercharger 35, and the air cleaner 36 disposed at the tip of the intake pipe 32 are included.

  The exhaust system 40 includes an exhaust manifold 41 connected to each cylinder of the engine body 20, an exhaust pipe 42 connected to a downstream gathering portion of the exhaust manifold 41, and a turbine of the supercharger 35 disposed in the exhaust pipe 42. And a diesel particulate filter (hereinafter referred to as “DPNR”) 43 interposed in the exhaust pipe 42. The exhaust manifold 41 and the exhaust pipe 42 constitute an exhaust passage.

  The EGR device 50 includes an exhaust recirculation pipe 51 that constitutes a passage for recirculating exhaust gas (EGR passage), an EGR control valve 52 interposed in the exhaust recirculation pipe 51, and an EGR cooler 53. The exhaust gas recirculation pipe 51 communicates the upstream exhaust passage (exhaust manifold 41) of the turbine 35b and the downstream intake passage (intake manifold 31) of the throttle valve 33. The EGR control valve 52 can change the amount of exhaust gas to be recirculated (exhaust gas recirculation amount, EGR gas flow rate) in response to a drive signal from the electric control device 60.

  The electrical control device 60 is connected to each other via a bus 61, a ROM 62 that stores programs executed by the CPU 61, tables (look-up tables, maps), constants, and the like, and the CPU 61 temporarily stores data as necessary. The microcomputer includes a RAM 63, a backup RAM 64 that stores data while the power is on, and holds the stored data while the power is shut off, an interface 65 including an AD converter, and the like.

  The interface 65 includes a hot-wire air flow meter 71 disposed in the intake pipe 32, an intake air temperature sensor 72 provided in an intake passage downstream of the throttle valve 33 and downstream of a portion to which the exhaust gas recirculation pipe 51 is connected. An intake pipe pressure sensor 73, a crank position sensor 74, an accelerator opening sensor 75, and a side wall surface of each cylinder disposed in the intake passage downstream of the valve 33 and downstream of the portion where the exhaust gas recirculation pipe 51 is connected. Are connected to the in-cylinder soot concentration sensor 76 (see FIG. 2), and signals from these sensors are supplied to the CPU 61.

  The interface 65 is connected to the fuel injection valve 21, the fuel injection pump 22, the throttle valve actuator 33a, and the EGR control valve 52, and sends drive signals to these in accordance with instructions from the CPU 61. Yes.

  The hot-wire air flow meter 71 measures the mass flow rate of intake air (intake air amount per unit time, fresh air amount per unit time) passing through the intake passage and represents the same mass flow rate Ga (air flow rate Ga). A signal is generated. The intake air temperature sensor 72 detects the temperature of the gas drawn into the cylinder (ie, the combustion chamber, the cylinder) of the engine 10 (ie, the intake air temperature), and generates a signal representing the intake air temperature Tb. Yes. The intake pipe pressure sensor 73 detects the pressure of gas taken into the cylinder of the engine 10 (that is, the intake pipe pressure) and generates a signal representing the intake pipe pressure Pb.

  The crank position sensor 74 detects the absolute crank angle of each cylinder, and generates a signal that represents the actual crank angle CAact and also represents the engine rotational speed NE that is the rotational speed of the engine 10. The accelerator opening sensor 75 detects an operation amount of the accelerator pedal AP and generates a signal representing the accelerator operation amount Accp. The in-cylinder soot concentration sensor 76 detects the soot concentration in the combustion chamber and generates a signal representing the actual in-cylinder soot concentration CSootact.

(Outline of gas flow around the combustion chamber)
FIG. 2 schematically shows a state in which gas is sucked from the intake manifold 31 into a cylinder (cylinder, combustion chamber) of a certain cylinder, and the gas sucked into the combustion chamber is discharged to the exhaust manifold 41. It is a figure. As shown in FIG. 2, the gas sucked into the combustion chamber (accordingly, in-cylinder gas) includes fresh air sucked from the tip of the intake pipe 32 through the throttle valve 33, and exhaust gas recirculation pipe 51. EGR gas sucked through the EGR control valve 52 is included.

  The ratio of the amount of EGR gas to the sum of the amount of fresh air (mass) to be sucked and the amount of mass of EGR (mass) to be sucked (that is, the EGR rate) is appropriately controlled by the electric control device 60 (CPU 61) according to the operating state. It changes according to the opening of the throttle valve 33 and the opening of the EGR control valve 52.

  The fresh air and EGR gas are sucked into the combustion chamber as the piston descends via the intake valve Vin opened in the intake stroke, and become in-cylinder gas. The in-cylinder gas is sealed in the combustion chamber when the intake valve Vin closes near the time when the piston reaches compression bottom dead center, and is compressed as the piston rises in the subsequent compression stroke.

  When the predetermined timing (pilot fuel injection start timing CAinjp) comes, pilot injection is first performed as described above. Pilot-injected (liquid) fuel immediately becomes fuel vapor due to heat received from the in-cylinder gas that has become hot due to compression. As the time elapses, the gas in the cylinder is taken in and becomes an air-fuel mixture that diffuses in a conical shape in the combustion chamber and diffuses and burns due to self-ignition at a predetermined timing.

  Thereafter, when a predetermined time (main fuel injection start time CAinjm) arrives, main injection is performed. As with the pilot-injected fuel, the main-injected fuel also becomes an air-fuel mixture and diffuses conically in the combustion chamber, and diffuses and burns due to self-ignition at a predetermined timing. The exhaust gas generated by the combustion is discharged into the exhaust passage as the piston moves up and down through the exhaust valve Vout that opens in the exhaust stroke.

(Outline of control method of soot discharge)
Next, a method of controlling the amount of soot discharged from the combustion chamber by the internal combustion engine control apparatus (hereinafter referred to as “the present apparatus”) according to the embodiment of the present invention configured as described above. The outline of will be described.

  FIG. 3 is a graph showing an example of a change in the in-cylinder soot concentration CSoot in the combustion chamber with respect to the crank angle CA. CAinjp is the pilot fuel injection start timing described above, and CAevo is the exhaust valve opening timing. The period from the pilot fuel injection start timing CAinjp to the exhaust valve opening timing CAevo corresponds to the “predetermined period including the combustion stroke”.

  As shown in FIG. 3, the in-cylinder soot concentration CSoot first increases after the pilot fuel injection start timing CAinjp, reaches a maximum value (hereinafter referred to as “peak value Y”) at a certain point, and thereafter. It changes with a change pattern of decreasing and converging to a certain value (hereinafter referred to as “final value X”) before the exhaust valve opening timing CAevo. This final value X is a value representing the amount of soot discharged from the combustion chamber.

  The in-cylinder soot concentration CSoot first increases because the soot generation reaction mainly occurs due to the reaction (combustion) of the pilot injected fuel (and subsequent main injected fuel), and the soot amount in the combustion chamber increases. Based on what to do. On the other hand, the decrease in the in-cylinder soot concentration CSoot after taking the peak value Y is based on the fact that the generated soot oxidation mainly occurs and the amount of soot in the combustion chamber decreases. After that, the in-cylinder soot concentration CSoot converges to the final value X because the soot oxidation reaction that causes a decrease in the soot amount due to a decrease in the gas temperature in the combustion chamber is substantially completed and the combustion This is based on the fact that the indoor soot amount is kept constant.

  That is, the peak value Y (corresponding to the in-cylinder soot concentration at the first time point) greatly depends on the degree of soot generation reaction in the combustion chamber and is a value representing the degree of soot generation reaction. The final value X (corresponding to the in-cylinder soot concentration at the second time point) (or the value “Y−X”) greatly depends on the degree of oxidation reaction of the soot generated in the combustion chamber, and the oxidation of the soot The value represents the degree of reaction.

  The degree of soot generation reaction in the combustion chamber depends on, for example, the pilot interval (the period from the pilot fuel injection start timing CAinjp to the main fuel injection start timing CAinjm), and is suppressed as the pilot interval becomes longer. This is based on the fact that the longer the pilot interval, the longer the period in which the fuel vapor of the pilot-injected fuel and oxygen in the combustion chamber are engaged and the extent to which these are engaged.

  On the other hand, the degree of oxidation reaction of Soot generated in the combustion chamber depends on, for example, the EGR rate, and is promoted as the EGR rate is smaller. This is based on the fact that the oxygen concentration in the combustion chamber increases as the EGR rate decreases.

  From the above, the peak value Y and the final value X can be adjusted by controlling the above-described pilot interval and EGR rate (corresponding to the control parameter). That is, the change pattern of the in-cylinder soot concentration CSoot can be adjusted.

  By the way, if a sensor such as the in-cylinder soot concentration sensor 76 is used, the combustion state becomes an optimum state from a comprehensive viewpoint in a certain steady operation state (command fuel injection amount Qfin, engine rotational speed NE). The change pattern of the in-cylinder soot concentration CSoot corresponding to the case (hereinafter referred to as “steady-fit pattern”, which corresponds to the reference pattern) is various operating states (command fuel injection amount Qfin, engine rotation speed NE). Can be acquired in advance.

  If the change pattern of the in-cylinder soot concentration CSoot matches the steady-state conforming pattern corresponding to the current operating state (command fuel injection amount Qfin, engine speed NE), the amount of soot discharged from the combustion chamber Becomes an appropriate value corresponding to the above-mentioned steady matching pattern.

  However, in the transient operation state, the change pattern of the in-cylinder soot concentration CSoot does not always match the steady matching pattern, and as a result, the amount of soot discharged from the combustion chamber is more than an appropriate value corresponding to the steady matching pattern. May also increase. Hereinafter, this will be described with reference to FIGS.

  FIG. 4 is a graph showing an example of a change pattern (see solid line) of the in-cylinder soot concentration CSoot when the soot generation reaction is excessive with respect to the steady matching pattern (see the broken line). In FIG. 4, XTA is a final value corresponding to the steady matching pattern, and YTA is a peak value corresponding to the steady matching pattern (the same applies to FIG. 5).

  In this example, since the soot generation reaction is excessive, the peak value Y is larger than the peak value YTA corresponding to the steady-fit pattern, and as a result, the final value X corresponds to the final value XTA corresponding to the steady-fit pattern. (That is, the amount of soot discharged from the combustion chamber is larger than an appropriate value corresponding to the steady matching pattern).

  FIG. 5 is a graph showing an example of a change pattern of the in-cylinder soot concentration CSoot (see the solid line) when the soot oxidation reaction is insufficient with respect to the steady matching pattern (see the broken line).

  In this example, since the oxidation reaction of the soot is insufficient, the extent to which the in-cylinder soot concentration CSoot decreases from the peak value Y (= YTA) becomes small. As a result, the final value X becomes a steady conforming pattern. The value is larger than the corresponding final value XTA (that is, the amount of soot discharged from the combustion chamber is larger than an appropriate value corresponding to the steady matching pattern).

  Here, the value X / Y is introduced as a value representing the characteristic of the change pattern of the in-cylinder soot concentration CSoot (the characteristic index value), and the final value / maximum value (= XTA / YTA) corresponding to the steady-fit pattern is obtained. Assuming C, the value X / Y tends to be smaller than the value C when the soot formation reaction is excessive as shown in FIG. Therefore, when the value X / Y is smaller than the value C, if the soot generation reaction is suppressed, the change pattern of the in-cylinder soot concentration CSoot can be brought close to (matched with) the steady matching pattern, and as a result, transient operation is performed. Even in the state, the amount of soot discharged from the combustion chamber can be immediately brought close to an appropriate value corresponding to the steady matching pattern. The value X / Y corresponds to the “ratio of the in-cylinder soot concentration at the second time point to the in-cylinder soot concentration at the first time point”.

  On the other hand, as shown in FIG. 5, when the Soot oxidation reaction is insufficient, the value X / Y tends to be larger than the value C. Therefore, when the value X / Y is larger than the value C, if the soot oxidation reaction is promoted, the change pattern of the in-cylinder soot concentration CSoot can be brought close to (matched with) the steady-fit pattern, and as a result, transient operation is performed. Even in the state, the amount of soot discharged from the combustion chamber can be immediately brought close to an appropriate value corresponding to the steady matching pattern.

  Therefore, the present apparatus identifies the final value X and the peak value Y from the history of the actual in-cylinder soot concentration CSootact obtained from the in-cylinder soot concentration sensor 76 in the previous combustion cycle, and the value X / Y is a value C. Is smaller, the pilot interval at the time of this fuel injection is lengthened in order to suppress the soot generation reaction. On the other hand, when the value X / Y in the previous combustion cycle is larger than the value C, the present apparatus reduces the EGR rate in order to promote the soot oxidation reaction.

  As described above, the present apparatus controls the control parameter based on the history of the actual in-cylinder soot concentration CSootact obtained from the in-cylinder soot concentration sensor 76, and corresponds the amount of soot discharged from the combustion chamber to the steady-fit pattern. Control to approach the appropriate value. The above is the outline of the control method of the soot discharge amount.

(Actual operation)
Next, actual operation of the control apparatus for an internal combustion engine configured as described above will be described. The CPU 61 is configured to repeatedly execute a series of routines for controlling the value X / Y shown by the flowcharts in FIGS. 6 and 7 every elapse of a predetermined time. Therefore, when the predetermined timing comes, the CPU 61 starts processing from step 600 and proceeds to step 605 to determine whether or not the intake valve Vin has changed from the open state to the closed state (when the intake valve is closed (IVC)). If it is determined as “No”, the process immediately proceeds to step 695 to end the present routine tentatively.

  Assuming that the intake valve closing time has arrived, the CPU 61 determines “Yes” when it proceeds to step 605 and proceeds to step 610, at which time the IVC crank angle CAivc is acquired from the crank position sensor 74. Is set to the actual crank angle CAact value, the IVC in-cylinder gas pressure Pgivc is set to the current intake pipe pressure Pb value obtained from the intake pipe pressure sensor 73, and the IVC in-cylinder gas temperature Tgivc is set to the intake air temperature. The current intake air temperature Tb obtained from the sensor 72 is set.

  Subsequently, the CPU 61 proceeds to step 615 to set the IVC hour cylinder gas pressure Pgivc, the IVC hour cylinder gas temperature Tgivc, the IVC hour cylinder volume Vg (CAivc), The total mass Gcyl of the in-cylinder gas is obtained based on the equation described in step 615 based on the state equation. The IVC in-cylinder volume Vg (CAivc) is a value when CA = CAivc in the in-cylinder volume Vg (CA) which is a function of the crank angle CA obtained from the design specifications. R is a gas constant (a constant in this example). According to this calculation, at the time of IVC, the pressure and temperature of the in-cylinder gas are close to the set IVC in-cylinder gas pressure Pgivc and the set IVC in-cylinder gas temperature Tgivc, respectively. Based on the facts.

  Next, the CPU 61 proceeds to step 620 and uses the current air flow rate Ga obtained from the air flow meter 71, the current engine speed NE obtained based on the output of the crank position sensor 74, and Ga, NE as arguments. Using the function func, the mass Gn of fresh air sucked into the combustion chamber in the current intake stroke is obtained.

  Subsequently, the CPU 61 proceeds to step 625 to execute the actual intake stroke based on the total mass Gcyl of the in-cylinder gas thus determined, the calculated fresh air mass Gn, and the formula described in step 625. Calculate EGR rate Regract.

  Next, the CPU 61 proceeds to step 630, where the current accelerator opening Accp obtained by the accelerator opening sensor 75, the current engine speed NE obtained from the crank position sensor 74, and the table (map) shown in FIG. ) The command fuel injection amount Qfin (= command pilot fuel injection amount Qp + command main fuel injection amount Qm) is obtained from MapQfin. The table MapQfin is a table that defines the relationship between the accelerator opening degree Accp, the engine speed NE, and the command fuel injection amount Qfin (= Qp + Qm), and is stored in the ROM 62.

  Next, the CPU 61 proceeds to step 635, and from the command fuel injection amount Qfin, the engine speed NE, and the table MapCAinj shown in FIG. 11, the pilot fuel injection start time (crank angle) CAinjp and the main fuel injection start time (crank angle). ) Determine CAinjm. The table MapCAinj is a table that defines the relationship between the command fuel injection amount Qfin and the engine rotational speed NE, the pilot fuel injection start timing CAinjp, and the main fuel injection start timing CAinjm, and is stored in the ROM 62.

  Subsequently, the CPU 61 proceeds to step 640 to determine the fuel injection pressure Pcr from the command fuel injection amount Qfin, the engine speed NE, and the table MapPcr shown in FIG. The table MapPcr is a table that defines the relationship between the command fuel injection amount Qfin and the engine rotational speed NE and the fuel injection pressure Pcr, and is stored in the ROM 62.

  Next, the CPU 61 proceeds to step 645 and determines the target EGR rate Regrt from the commanded fuel injection amount Qfin, the engine speed NE, and the table MapRegrt. The table MapRegrt is a table that defines the relationship between the command fuel injection amount Qfin and the engine rotational speed NE, and the target EGR rate Regrt, and is stored in the ROM 62. Note that this target EGR rate Regrt is used when the combustion state becomes the optimum state from a comprehensive point of view in the steady operation state at the current operation state (command fuel injection amount Qfin, engine speed NE). It is a corresponding EGR rate, which is a steady fit value that has been adapted in advance through experiments or the like.

  Next, the CPU 61 proceeds to step 650, and determines the final value CSootTA (corresponding to the value XTA in FIGS. 4 and 5) corresponding to the above-described steady conforming pattern from the command fuel injection amount Qfin, the engine speed NE, and the table MapCSootTA. To do. The table MapCSootTA is a table that defines the relationship between the command fuel injection amount Qfin and the engine rotational speed NE, and the final value CSootTA corresponding to the steady matching pattern, and is stored in the ROM 62.

  Subsequently, the CPU 61 proceeds to step 655, and determines the above-described value C (corresponding to the value (XTA / YTA) in FIGS. 4 and 5) from the command fuel injection amount Qfin, the engine speed NE, and the table MapC. The table MapC is a table that defines the relationship between the command fuel injection amount Qfin, the engine speed NE, and the value C, and is stored in the ROM 62.

  Next, the CPU 61 proceeds to step 705 in FIG. 7, and the last value XootTA in the previous combustion cycle acquired by the routine described later is the last value CSootTA corresponding to the steady conforming pattern (see FIG. 3 to FIG. 5). It is determined whether or not the value is greater than CSootTAb. As the previous value CSootTAb, the value updated in step 730, which will be described later, at the time of the previous execution of this routine is used.

  First, the case where “Yes” is determined in the determination in step 705 will be described. In this case, the CPU 61 proceeds to step 710, and the value X / Y in the previous combustion cycle obtained from the last value X and the peak value Y in the previous combustion cycle acquired by the routine described later is determined in the previous step 655. It is determined whether or not the value is smaller than the value C, and if “Yes” is determined (that is, if the soot generation reaction is excessive), the process proceeds to step 715 and the pilot interval is determined in the previous step 635. The pilot fuel injection start timing CAinjp and the main fuel injection start timing CAinjm are corrected to be longer by a predetermined value ΔCA (constant) than the value obtained from the pilot fuel injection start timing CAinjp and the main fuel injection start timing CAinjm, Proceed to step 725.

  When it is determined as “No” in Step 710 (that is, when the Soot oxidation reaction is insufficient), the CPU 61 proceeds to Step 720 and sets the target EGR rate Regrt to a predetermined value from the value determined in the previous Step 645. The value is redetermined by a value ΔR (constant) and the process proceeds to step 725.

  When the CPU 61 proceeds to step 725, it instructs the EGR valve 52 to control so that the actual EGR rate Regract obtained in the previous step 625 becomes the target EGR rate Regrt. Specifically, for example, the opening degree of the EGR valve 52 is feedback controlled so that the actual EGR rate Regract becomes the target EGR rate Regrt based on the value obtained by PID processing of the difference between the actual EGR rate Regract and the target EGR rate Regrt. .

  Then, the CPU 61 proceeds to step 730, sets the previous value CSootTAb of the final value CSootTA corresponding to the steady matching pattern to the final value CSootTA (current value) corresponding to the steady matching pattern obtained in the previous step 650, The routine is temporarily terminated.

  As a result, if the soot production reaction is excessive in the previous combustion cycle, the pilot interval during the current fuel injection is lengthened, and as a result, the soot production reaction is suppressed in the current combustion cycle. On the other hand, when the Soot oxidation reaction is insufficient in the previous combustion cycle, the EGR rate is reduced, and as a result, the Soot oxidation reaction is promoted in the current combustion cycle.

  On the other hand, if the determination in step 705 is “No”, the CPU 61 proceeds to step 725 immediately. That is, in this case, the pilot interval and the EGR rate are not adjusted. This is because when the determination in step 705 is “No”, the amount of soot discharged from the combustion chamber is equal to or less than an appropriate value corresponding to the steady conforming pattern, and thus the change in the in-cylinder soot concentration CSoot. Based on no need to adjust the pattern. This suppresses unnecessary control of control parameters such as the pilot interval and the EGR rate.

  Further, the CPU 61 is configured to repeatedly execute a routine for performing fuel injection control shown in the flowchart of FIG. 8 every elapse of a predetermined time. Therefore, when the predetermined timing is reached, the CPU 61 starts the process from step 800, proceeds to step 805, and the actual crank angle CAact coincides with the pilot fuel injection start timing CAinjp determined in the previous step 635 or step 715. If the determination is “No”, the process proceeds to step 815 to check whether the actual crank angle CAact coincides with the main fuel injection start timing CAinjm determined in the previous step 635 or step 715. If “No” is determined, the process immediately proceeds to step 895 to end the present routine tentatively.

  Assuming that the actual crank angle CAact coincides with the pilot fuel injection start timing CAinjp, the CPU 61 determines “Yes” when it proceeds to step 805, proceeds to step 810, and proceeds to the corresponding fuel injection valve 21. Then, an instruction to inject fuel of the command pilot fuel injection amount Qp determined in step 630 is issued, and in the subsequent step 815, “No” is determined. Then, the process proceeds to step 895, and this routine is temporarily ended. Thereby, the fuel of the command pilot fuel injection amount Qp is injected with the fuel injection pressure Pcr described above.

  Thereafter, assuming that the actual crank angle CAact coincides with the main fuel injection start timing CAinjm, the CPU 61 makes a “No” determination at step 805 to determine “Yes” when the operation proceeds to step 815, and then proceeds to step 820. After instructing the corresponding fuel injection valve 21 to inject the fuel of the command main fuel injection amount Qm determined in step 630, the routine proceeds to step 895 and this routine is temporarily terminated. Thereby, the fuel of the command main fuel injection amount Qm is injected with the fuel injection pressure Pcr described above.

  Further, the CPU 61 repeatedly executes a routine for calculating the value X / Y shown by the flowchart in FIG. 9 every elapse of a predetermined time. Accordingly, when the predetermined timing is reached, the CPU 61 starts processing from step 900, proceeds to step 905, and the pilot fuel injection start timing CAinjp in which the actual crank angle CAact is determined in the previous step 635 or step 715. It is determined whether or not it is during the exhaust valve opening timing CAevo, and if “No” is determined, the process immediately proceeds to step 995 to end the present routine tentatively.

  Assuming that the actual crank angle CAact coincides with the pilot fuel injection start timing CAinjp, the CPU 61 makes a “Yes” determination at step 905 to proceed to step 910 where the current value obtained from the in-cylinder soot concentration sensor 76 is obtained. The actual in-cylinder soot concentration CSootact is acquired.

  Next, the CPU 61 proceeds to step 915 and stores the current in-cylinder soot concentration CSootact acquired in step 910 in a predetermined area of the RAM 63 in correspondence with the current actual crank angle CAact.

  Subsequently, the CPU 61 proceeds to step 920 and determines whether or not the current actual crank angle CAact coincides with the exhaust valve opening timing CAevo. The present time is immediately after the actual crank angle CAact coincides with the pilot fuel injection start timing CAinjp. Therefore, the CPU 61 makes a “No” determination at step 920 to immediately proceed to step 995 to end the present routine tentatively.

  Such a series of processing (steps 905, 910, 915, and 920) is repeatedly executed until the actual crank angle CAact coincides with the exhaust valve opening timing CAevo. Thus, the history of the actual in-cylinder soot concentration CSootact from the pilot fuel injection start timing CAinjp to the exhaust valve opening timing CAevo is sequentially stored in the RAM 63 in correspondence with the actual crank angle CAact.

  When the actual crank angle CAact coincides with the exhaust valve opening timing CAevo, the CPU 61 determines “Yes” when the routine proceeds to step 920 and proceeds to step 925 to set the final value X to the actual in-cylinder soot concentration CSootact. (That is, the actual in-cylinder soot concentration CSootact at the exhaust valve opening timing CAevo).

  Subsequently, the CPU 61 proceeds to step 930 and specifies the maximum value from the history data of the actual in-cylinder soot concentration CSootact from the pilot fuel injection start timing CAinjp to the exhaust valve opening timing CAevo stored in the RAM 63. Then, after setting the peak value Y to the maximum value, the routine proceeds to step 995 and this routine is once ended.

  Thereby, since the final value X and the peak value Y are acquired, the value X / Y can be calculated. The final value X and the value X / Y are used in step 705 and step 710, respectively, in the next execution of the routine shown in FIG.

  As described above, step 915 corresponds to storage means, and steps 715 and 720 correspond to control means.

  As described above, according to the embodiment of the control device of the present invention, the actual period from the pilot fuel injection start timing CAinp detected and stored by the in-cylinder soot concentration sensor 76 to the exhaust valve opening timing CAevo. The peak value Y and the final value X are specified from the history of the in-cylinder soot concentration CSootact. In the previous combustion cycle, the value X / Y representing the characteristic of the change pattern of the in-cylinder soot concentration CSoot is smaller than the final value / maximum value (= XTA / YTA) (= C) corresponding to the steady matching pattern. In this case, it is determined that the soot generation reaction is excessive in the previous combustion cycle, and the pilot interval during the current fuel injection is lengthened. As a result, the soot generation reaction is suppressed in the current combustion cycle.

  On the other hand, if the value X / Y is greater than the value C in the previous combustion cycle, it is determined that the Soot oxidation reaction is insufficient in the previous combustion cycle, and the EGR rate is reduced. As a result, the oxidation reaction of Soot is promoted in the current combustion cycle. Thereby, even in the transient operation state, the change pattern of the in-cylinder soot concentration CSoot can be immediately adjusted so as to approach the steady matching pattern, and as a result, the amount of soot discharged from the combustion chamber corresponds to the steady matching pattern. Immediate access to appropriate values.

  The present invention is not limited to the above embodiment, and various modifications can be employed within the scope of the present invention. For example, in the above embodiment, when it is determined “No” in step 705 of FIG. 7, the CPU 61 proceeds to step 725 immediately and does not control the control parameters such as the pilot interval and the EGR rate. However, the target EGR rate Regrt may be increased.

  This is because if the determination in step 705 of FIG. 7 is “No”, the amount of soot discharged from the combustion chamber is less than or equal to an appropriate value corresponding to the steady-state conforming pattern, so that the amount of NOx is decreased. Therefore, there is room for increasing the amount of soot. When this configuration is applied, the routine shown in FIG. 13 in which step 1305 is added to the routine shown in FIG. 7 is executed instead of the routine shown in FIG. According to this, the amount of soot can be increased while the amount of NOx can be decreased, and as a result, the amount of soot discharged from the combustion chamber can be suppressed to the appropriate value or less (or in the vicinity). The amount of NOx discharged from the combustion chamber can be reduced.

  Further, in the above-described embodiment, it is configured to select whether to increase the pilot interval or decrease the EGR rate depending on whether the value X / Y is smaller than the value C, but the value X / Y is a value. The pilot interval may be lengthened when smaller than C1, and the EGR rate may be decreased when the value X / Y is larger than the value C2 larger than the value C1.

  Moreover, in the said embodiment, although the said value C which is the object compared with value X / Y is made variable according to a driving | running state (refer step 655), it is good also as fixed.

  In the above embodiment, when the value X / Y is smaller than the value C, the pilot interval is lengthened to suppress the soot generation reaction, but the swirl strength is suppressed to suppress the soot generation reaction. May be changed. This is based on the following reason.

  That is, by adjusting the strength of the swirl (swirl rate), it is possible to change the degree to which the fuel vapor of the main injected fuel is related to the mixture after combustion based on the pilot injected fuel. The degree to which the fuel vapor and oxygen in the combustion chamber are involved can be changed. Therefore, even if the strength of the swirl (swirl rate) is adjusted, the soot generation reaction can be suppressed.

  In the above embodiment, a steady matching pattern is used as the reference pattern, and the value C to be compared with the value X / Y is set to the final value / maximum value (= XTA / YTA) corresponding to the steady matching pattern. (See step 655), but using another pattern different from the steady matching pattern as the reference pattern, and setting the value C to the final value / maximum value corresponding to the other pattern. May be.

  In the above-described embodiment, the steady-state adaptation value of the EGR rate is used as the target EGR rate Regr (see step 645), but other values other than the steady-state adaptation value may be used as the target EGR rate Regrt. Good.

  In the above embodiment, the exhaust valve opening timing CAevo is used as the second time point. However, as the second time point, the change rate (absolute value) of the actual in-cylinder soot concentration CSootact is a predetermined minute value. You may use the time when it became below the value, or the time when the gas temperature in a combustion chamber became below the predetermined temperature which the reaction regarding Soot substantially complete | finishes.

  In the above embodiment, the value X / Y is used as a value (characteristic index value) representing the characteristic of the change pattern of the in-cylinder soot concentration CSoot, but the value (Y−X) is used as the characteristic index value. / Y may be used.

  In addition, in the above embodiment, the amount by which the pilot interval is lengthened is set to a predetermined value ΔCA (a constant value) (see step 715), but the amount by which the pilot interval is lengthened is the value X / Y and value C. It may be changed according to the degree of difference (for example, difference, ratio, etc.). Similarly, in the above embodiment, the amount by which the EGR rate is decreased is set to a predetermined value ΔR (a constant value) (see step 720), but the amount by which the EGR rate is decreased is set to the values X / Y and C It may be changed according to the degree of difference (for example, difference, ratio).

1 is a schematic configuration diagram of an entire system in which an internal combustion engine control device according to an embodiment of the present invention is applied to a four-cylinder internal combustion engine (diesel engine). It is the figure which showed typically a mode that the gas was suck | inhaled from the intake manifold in the cylinder (cylinder) of a certain cylinder, and the gas suck | inhaled in the cylinder was discharged | emitted to an exhaust manifold. It is the graph which showed an example of the change of the in-cylinder soot density | concentration in a combustion chamber with respect to a crank angle. It is the graph which showed the example of the change pattern (solid line) of the in-cylinder soot density | concentration in case the generation reaction of Soot is excessive with respect to a steady fitting pattern (dashed line). It is the graph which showed the example of the change pattern (solid line) of the in-cylinder soot density | concentration in case the oxidation reaction of Soot produced | generated with respect to the steady fitting pattern (broken line) is insufficient. 3 is a flowchart showing a first half of a routine for controlling a value X / Y executed by a CPU shown in FIG. 1. 3 is a flowchart showing a second half of a routine for controlling a value X / Y executed by a CPU shown in FIG. 1. 2 is a flowchart showing a routine for performing fuel injection control executed by a CPU shown in FIG. 3 is a flowchart showing a routine for calculating a value X / Y executed by a CPU shown in FIG. 1. 7 is a table for determining a command fuel injection amount to be referred to when the CPU shown in FIG. 1 executes the routine shown in FIG. FIG. 7 is a table for determining a fuel injection timing to be referred to when the CPU shown in FIG. 1 executes the routine shown in FIG. 6. 7 is a table for determining a fuel injection pressure to be referred to when the CPU shown in FIG. 1 executes the routine shown in FIG. It is the flowchart which showed the second half part of the routine for controlling value X / Y which CPU of the control apparatus of the internal combustion engine which concerns on the modification of embodiment of this invention performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 ... Fuel injection valve, 52 ... EGR control valve, 60 ... Electric control device, 61 ... CPU, 72 ... Intake air temperature sensor, 73 ... Intake pipe pressure sensor, 74 ... Crank position sensor, 76 ... In-cylinder soot concentration sensor

Claims (14)

The present invention is applied to an internal combustion engine having an in-cylinder soot concentration sensor that directly detects an in-cylinder soot concentration that is a concentration of soot in a combustion chamber of the internal combustion engine,
Storage means for storing a history of the detected in-cylinder soot concentration within a predetermined period including a combustion stroke;
Control means for controlling a control parameter of the internal combustion engine to control the amount of soot discharged from the combustion chamber based on the stored history of the in-cylinder soot concentration;
The control apparatus of the internal combustion engine provided with. The control apparatus for an internal combustion engine according to claim 1,
The control means includes
A control parameter of the internal combustion engine is controlled based on the in-cylinder soot concentration history so that a change pattern of the in-cylinder soot concentration obtained from the stored in-cylinder soot concentration history becomes a reference pattern. A control apparatus for an internal combustion engine configured as described above. The control apparatus for an internal combustion engine according to claim 2,
The control means includes
Of the stored history of the in-cylinder soot concentration, the in-cylinder soot concentration at a first time point that is a value representing the degree of soot generation reaction in the combustion chamber, and the soot generated in the combustion chamber Control of the internal combustion engine configured to control the control parameter of the internal combustion engine based on the in-cylinder soot concentration at a second time point after the first time point, which is a value representing the degree of oxidation reaction of apparatus. The control apparatus for an internal combustion engine according to claim 3,
The control means includes
When the time point corresponding to the maximum value in the stored history of the in-cylinder soot concentration is used as the first time point, the in-cylinder soot concentration that has decreased from the maximum value has converged as the second time point. A control device for an internal combustion engine configured to use a time point after the determined time point. The control apparatus for an internal combustion engine according to claim 4,
The control means includes
A control apparatus for an internal combustion engine configured to use a valve opening time of an exhaust valve as the second time. The control device for an internal combustion engine according to any one of claims 4 and 5,
The control means includes
Based on the in-cylinder soot concentration at the first time point and the in-cylinder soot concentration at the second time point, a characteristic index value that is a value representing a characteristic of a change pattern of the in-cylinder soot concentration is obtained, A control apparatus for an internal combustion engine configured to control a control parameter of the internal combustion engine based on a characteristic index value. The control apparatus for an internal combustion engine according to claim 6,
The control means includes
The control apparatus for an internal combustion engine configured to use a ratio of the in-cylinder soot concentration at the second time point to the in-cylinder soot concentration at the first time point as the characteristic index value. The control apparatus for an internal combustion engine according to claim 7,
The control means includes
A control device for an internal combustion engine configured to control the control parameter to suppress a soot generation reaction when the ratio is smaller than a predetermined value corresponding to the reference pattern. The control apparatus for an internal combustion engine according to claim 8,
The control means includes
A control apparatus for an internal combustion engine configured to increase a pilot interval, which is a period between pilot injection and main injection, when the ratio is smaller than the predetermined value. The control apparatus for an internal combustion engine according to claim 7,
The control means includes
A control device for an internal combustion engine configured to control the control parameter to promote an oxidation reaction of Soot when the ratio is equal to or greater than a predetermined value corresponding to the reference pattern. The control apparatus for an internal combustion engine according to claim 10,
The control means includes
A control apparatus for an internal combustion engine configured to reduce an EGR rate when the ratio is equal to or greater than the predetermined value. The control apparatus for an internal combustion engine according to any one of claims 8 to 11,
The control means includes
A control apparatus for an internal combustion engine configured to change the predetermined value according to an operating state of the internal combustion engine. The control apparatus for an internal combustion engine according to any one of claims 2 to 12,
The control means includes
The control parameter is not controlled when the in-cylinder soot concentration after the time when it is determined that the in-cylinder soot concentration has converged is equal to or less than the value corresponding to the reference pattern at the same time. Control device for an internal combustion engine. The control apparatus for an internal combustion engine according to any one of claims 2 to 12,
The control means includes
An internal combustion engine configured to increase the EGR rate when the in-cylinder soot concentration at or after the time when it is determined that the in-cylinder soot concentration has converged is equal to or less than the value corresponding to the reference pattern at the same time. Engine control device.

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