Patent Publication Number: US-2017356351-A1

Title: Control apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on Japanese Patent Application No. 2014-260065 filed on Dec. 24, 2014, the disclosure of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a control apparatus that controls an internal combustion engine to directly inject fuel into a cylinder mounted in a vehicle. 
     BACKGROUND ART 
     There has been widely used an internal combustion engine of a direct injection type in which fuel is directly injected into a cylinder. In the internal combustion engine of this type, as compared with an internal combustion engine of a type in which the fuel is injected into an intake port, it is concerned that a particulate matter (PM) is discharged and that the number of particulate matters (PN) is increased. At a time of a transient operation when an operation state of the internal combustion engine is in transition, in particular, it is markedly concerned that the PM is discharged and that the PN is increased. 
     As causes to generate the PM and to increase the PN are considered that the fuel is attached to an interior of the cylinder and that the fuel becomes nonuniform in the cylinder. In short, when the fuel is directly injected into the cylinder, the fuel is attached to the cylinder and a piston as it is liquid. Further, the fuel and air are not sufficiently mixed with each other in the cylinder, so that the fuel becomes partially rich in the cylinder. Hence, as a countermeasure against the generated PM and the increased PN in the internal combustion engine of a direct injection type, it is supposed to be effective that the fuel in the liquid state is restrained from being attached to the interior of the cylinder and that a mixing of the fuel and the air is accelerated. 
     In Patent Literature 1, as a control apparatus of an internal combustion engine of a direct injection type, a control apparatus is disclosed which changes a setting of an operation of an internal combustion engine so as to restrain fuel in the liquid state from being attached to the interior of the cylinder. In more detail, the control apparatus disclosed in Patent Literature 1 temporarily changes a fuel injection timing to thereby reduce the fuel attached to the interior of the cylinder as it is liquid. 
     However, even if the fuel injection timing is changed, it is not avoided that the fuel becomes nonuniform in the cylinder. Hence, only by a method of changing the fuel injection timing, it is difficult to sufficiently restrain the PM from being generated and the PN from being increased at the time of a transient operation of the internal combustion engine. 
     Further, in the control apparatus disclosed in Patent Literature 1, an effect of a state of the internal combustion engine such as temperature is not taken into account at the time of changing the fuel injection timing. The temperature of the internal combustion engine has an effect on the PM being generated and the PN being increased, so that also in this point of view, it is considered that the control apparatus disclosed in Patent Literature 1 cannot sufficiently restrain the PM from being generated and the PN from being increased. 
     PRIOR ART LITERATURES 
     Patent Literature 
     Patent Literature 1: JP H09-68071 A 
     SUMMARY OF INVENTION 
     It is an object of the present disclosure to provide a control apparatus of an internal combustion engine that is suitable to a state of the internal combustion engine and that can restrain a particulate matter from being generated. 
     According to one aspect of the present disclosure, a control apparatus controls an internal combustion engine mounted in a vehicle to directly inject fuel into a cylinder. The control apparatus includes: a PM-PN exhaust determination part that determines whether or not an operation state of the internal combustion engine is a PM-PN exhaust state in which a particulate matter generated due to a fuel combustion in the cylinder is increased as compared with other operation states; and a control value calculation part that calculates a control value of an actuator to regulate at least one of a fuel injection timing, a number of injections of the fuel, a fuel injection pressure, an intake valve timing, and an exhaust valve timing of the internal combustion engine. The control value calculation part includes an in-cylinder state estimation part that estimates a state to which the cylinder belongs between a plurality of PM-PN generation states. The PM-PN generation states are states in which the particulate matter is easily generated as compared with the other state, and different from each other in a cause to generate the particulate matter. Further, in a case where the operation state of the internal combustion engine is determined to be the PM-PN exhaust state, the control value calculation part calculates the control value in such a way as to eliminate the PM-PN generation state according to the PM-PN generation state to which the state in the cylinder belongs. 
     In the present disclosure, in a case where the state in the cylinder of the internal combustion engine is determined to be the PM-PN exhaust state, the control value calculation part calculates the control value of the actuator to regulate the fuel injection timing or the like in such a way as to eliminate the PM-PN generation state according to the PM-PN generation state to which the state in the cylinder belongs. Hence, in the present disclosure, it is possible to restrict a generation of the PM-PN exhaust state in such a way as to be suitable to the state of the internal combustion engine. 
     According to the present disclosure, it is possible to provide a control apparatus of an internal combustion engine that can restrict a generation of the PM-PN exhaust state in such a way as to be suitable to the state of the internal combustion engine. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The objective described above, the other objectives, features, and advantages of the present disclosure will be made more apparent from the following detailed description with reference to the accompanying drawings. 
         FIG. 1  is a schematic configuration diagram of a drive system to which an ECU is applied according to an embodiment of the present disclosure. 
         FIG. 2  is a control block diagram for describing functional blocks of the ECU shown in  FIG. 1 . 
         FIG. 3  is a flow chart of a base routine that the ECU performs according to the embodiment of the present disclosure. 
         FIG. 4  is a flow chart showing a processing flow in a PM-PN exhaust determination shown in  FIG. 3 . 
         FIG. 5  is a time chart showing one example of an operation state of a vehicle and an engine. 
         FIG. 6  is a flow chart showing a processing flow in an in-cylinder state estimation shown in  FIG. 3 . 
         FIG. 7  is a chart showing a cold map. 
         FIG. 8  is a chart showing a hot map. 
         FIG. 9  is a flow chart showing a processing flow in an actuator control value calculation for a restrictive control of PM-PN shown in  FIG. 3 . 
         FIG. 10  is a time chart showing one example of a control performed by the ECU in a case where the operation state in a cylinder is a WET state. 
         FIG. 11  is a time chart showing one example of a control performed by the ECU in a case where the operation state in the cylinder is a nonuniform state. 
         FIG. 12  is a time chart showing one example of a control performed by the ECU in a case where the operation state in the cylinder is a high temperature state. 
     
    
    
     EMBODIMENT FOR CARRYING OUT INVENTION 
     Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings. In order to easily understand a description, the same constituent elements in the respective drawings will be denoted by the same reference symbols as far as possible and a duplicate description of the element will be omitted. 
     First, a general description of an ECU  24  according to an embodiment of the present disclosure will be made with reference to  FIG. 1  and  FIG. 2 . The ECU  24  is applied to a drive system of a vehicle. The ECU  24  is mainly constructed of a microcomputer. First, a construction of an engine  1  which is an object to be controlled by the ECU  24  will be described. 
     The engine  1  is an internal combustion engine of a direct injection type and includes a plurality of cylinders  50 . In  FIG. 1 , only one cylinder  50  is shown but, in reality, multiple cylinders  50  are arranged side by side. In each of the cylinders  50 , a piston  56  reciprocated in a vertical direction is arranged. A combustion chamber  54  is formed between an upper inside wall surface of each cylinder  50  and the piston  56 . The engine  1  is provided with an intake pipe  2 , which intakes air for combustion from an outside, and an exhaust pipe  20 , which guides an exhaust gas discharged from the engine  1  to the outside. 
     In a most upstream portion of the intake pipe  2 , a filter-shaped air cleaner  3  is provided to remove a foreign matter from the air passing through the intake pipe  2 . Further, on a downstream side of the air cleaner  3 , an air flowmeter  4  to detect a flow rate of the intake air is provided. 
     On a downstream side of the flowmeter  4 , a throttle valve  6  to open or close a flow channel in the intake pipe  2  is provided. The throttle valve  6  is driven by a DC motor  5  and can have its opening (throttle opening) regulated. The throttle opening is sensed by a throttle sensor  7 . 
     On a downstream side of the throttle valve  6 , a surge tank  8  is provided. The surge tank  8  is provided with an intake pressure sensor  9  to sense an intake pressure. Between the surge tank  8  and an intake port  51  of each cylinder  50 , an intake manifold  10  to introduce the air into each cylinder  50  is interposed. 
     The engine  1  is provided with an intake valve  28  to open or close a flow channel between the intake port  51  and the combustion chamber  54 . Further, the engine  1  is provided with an exhaust valve  29  to open or close a flow channel between the exhaust port  52  and the combustion chamber  54 . The intake valve  28  is provided with a variable valve timing mechanism  30  to regulate a valve timing thereof. Further, the exhaust valve  29  is provided with a variable valve timing mechanism  31  to regulate a valve timing thereof. 
     A fuel injector  16  is provided near the intake valve  28  of each cylinder  50  of the engine  1  in such a way as to face the combustion chamber  54 . The fuel injector  16  has a delivery pipe  14  connected thereto. The delivery pipe  14  is extended to a fuel tank  11  via a high-pressure pump  13 . When the fuel injector  16  receives a control signal outputted from the ECU  24 , the fuel injector  16  is opened to inject fuel directly to the combustion chamber  54  in each cylinder  50 , the fuel being supplied from the fuel tank  11  and having its pressure regulated to a predetermined pressure by the high-pressure pump  13 . A pressure of the fuel supplied to the fuel injector  16  is sensed by a fuel pressure sensor  15  provided on an upstream side of the fuel injector  16 . 
     In an upper portion of the combustion chamber  54  of each cylinder  50 , an ignition plug  17  is provided. The ignition plug  17  makes a spark discharge and ignites an air-fuel mixture of the fuel and the air. 
     A cylinder block of the engine  1  is provided with a knock sensor  25 , a coolant temperature sensor  18 , and a crank angle sensor  19 . The knock sensor  25  senses a knocking of the engine  1  and outputs a signal corresponding to its sensing. Further, the coolant temperature sensor  18  senses a temperature of a coolant to cool the engine  1  and outputs a signal corresponding to its sensing. The crank angle sensor  19  senses a revolution of a crankshaft  58  at a predetermined crank angle and outputs a signal corresponding to its sensing. The ECU  24  receives the signals outputted from the knock sensor  25 , the coolant temperature sensor  18 , and the crank angle sensor  19  and uses the signals so as to control the engine  1 . For example, the ECU  24  carries out an operation on the basis of the signal outputted from the crank angle sensor  19  to thereby sense a crank angle and an engine speed. 
     On the other hand, the exhaust pipe  20  of the engine  1  is provided with an upstream catalyst  21  and a downstream catalyst  22  which clean the exhaust gas generated by the combustion of the fuel in the cylinders  50 . Further, on an upstream side of the upstream catalyst  21 , an exhaust gas sensor  23  to sense an air-fuel ratio or the like of the exhaust gas is provided. 
     A driver of the vehicle presses down an accelerator pedal  26  provided in the vehicle to thereby accelerate the vehicle. A pressing-down amount of the accelerator pedal  26  (accelerator opening) is sensed by an accelerator pedal senor  27 . The accelerator pedal senor  27  outputs a signal corresponding to the sensed accelerator opening. The ECU  24  receiving the signal makes the fuel injector  16  inject the fuel of a quantity corresponding to the accelerator opening to increase the fuel to be combusted in the combustion chamber  54  in the cylinder  50 , thereby bringing the vehicle into an acceleration state. 
     The ECU  24  receives the signals outputted from the various kinds of sensors as described above and performs various kinds of control routines stored in a ROM (storage medium) built therein. In this way, the ECU  24  controls a quantity of the fuel injected by the fuel injector  16 , a fuel injection timing, a fuel pressure by a high-pressure pump  13 , an opening/closing timing of the intake valve  28  and the exhaust valve  29 , and an ignition timing by the ignition plug  17  according to an operation state of the engine  1 . 
       FIG. 2  shows the ECU  24  as a functional control block diagram. The ECU  24  includes a PM-PN exhaust determination part  40 , a control value calculation part  46 , and an actuator regulation part  44 . 
     The PM-PN exhaust determination part  40  is a part to determine whether or not the operation state of the engine  1  is in a PM-PN exhaust state in which a particulate matter generated due to a fuel combustion in the cylinder is increased as compared with other operation state. Specifically, the PM-PN exhaust determination part  40  reads an accelerator opening, which is sensed by the accelerator pedal sensor  27 , and a fuel injection quantity, which is calculated from a sensed value of the fuel pressure sensor  15 , and determines whether or not the vehicle is in the acceleration state from these read values. This is because of the following reason: there is a strong correlation between the acceleration state of the vehicle and the discharged particulate matter, so that when the vehicle is brought into the acceleration state, it can be determined that the operation state of the engine  1  is brought into the PM-PN exhaust state. 
     In this regard, in the present embodiment, it is determined on the basis of the acceleration opening and the fuel injection quantity whether or not the vehicle is in the acceleration state, but the present disclosure is not limited to this. In other words, whether or not the vehicle is in the acceleration state can also be determined by the use of other index correlated to the acceleration state of the vehicle, such as a throttle opening, an intake air quantity, the number of revolutions and a load of the engine  1 , and a vehicle speed. 
     The control value calculation part  46  includes a control value calculation part  42  for a normal control (hereinafter referred to as “a normal calculation part  42 ”) and a control value calculation part  43  for a restrictive control of PM-PN (hereinafter referred to as “a restrictive calculation part  43 ”). The normal calculation part  42  is a part to calculate a control value for controlling each of actuators of the fuel injector  16 , the high-pressure pump  13 , and the variable valve timing mechanisms  30 ,  31  in a case where a PM-PN exhaust, which will be described later in detail, is not especially restricted. On the other hand, the restrictive calculation part  43  is a part to calculate a control value for controlling each of the actuators described above in a case where the PM-PN exhaust is restricted. 
     The restrictive calculation part  43  includes an in-cylinder state estimation part  43 A, an in-cylinder state specific control value calculation part  43 B, and a selection part  43 F. 
     The in-cylinder state estimation part  43 A is a part to estimate a state in the cylinder  50  of the engine  1 . Describing in more detail, the in-cylinder state estimation part  43 A reads the number of revolutions of the engine  1 , the load of the engine  1 , and the coolant temperature of the engine  1  and estimates which state of three PM-PN generation states of “a WET state”, “a nonuniform state”, and “a high temperature state”, the state in the cylinder  50  belongs to. 
     These three PM-PN generation states are states in which the particulate matter is easily generated as compared with other states and are classified on the basis of a generation factor of the particulate matter. “The WET state” is a state in which the fuel easily exists in a liquid state in the cylinder  50  as compared with “the nonuniform state”, and “the high temperature state” and in which it is concerned that the particulate matter is generated due to this. Further, “the nonuniform state” is a state in which a concentration of the fuel easily becomes nonuniform in the cylinder  50  as compared with “the WET state” and “the high temperature state” and in which it is concerned that the particulate matter is generated due to this. Still further, “the high temperature state” is a state in which a temperature in the cylinder  50  easily becomes high as compared with “the WET state” and “the nonuniform state” and in which it is concerned that the particulate matter is generated due to this. 
     In this regard, in the present embodiment, the state in the cylinder  50  is estimated on the basis of the number of revolutions, the load, and the coolant temperature of the engine  1 , but the present disclosure is not limited to this. In other words, the above-mentioned estimation can also be made by the use of other index correlated with the state in the cylinder  50  such as the throttle opening, the accelerator opening, the vehicle speed, the fuel injection quantity, and the intake air quantity. 
     Further, the in-cylinder state specific control value calculation part  43 B includes a control value calculation part  43 B 1  for a WET state, a control value calculation part  43 B 2  for a nonuniform state, and a control value calculation part  43 B 3  for a high temperature state. The control value calculation part  43 B 1  for a WET state is a part to calculate a control value for controlling each of the actuators of the fuel injector  16 , the high-pressure pump  13 , and the variable valve timing mechanisms  30 ,  31  in a case where it is estimated that the state in the cylinder  50  is the WET state. Similarly, the control value calculation part  43 B 2  for a nonuniform state calculates a control value for controlling each of the actuators in a case where it is estimated that the state in the cylinder  50  is the nonuniform state. Further, the control value calculation part  43 B 3  for a high temperature state calculates a control value for controlling each of the actuators in a case where it is estimated that the state in the cylinder  50  is the high temperature state. 
     The selection part  43 F selects one of the control values calculated by the control value calculation part  43 B 1  for a WET state, the control value calculation part  43 B 2  for a nonuniform state, and the control value calculation part  43 B 3  for a high temperature state on the basis of an estimation result in the in-cylinder state estimation part  43 A. 
     The ECU  24  further includes a selection part  41 . The selection part  41  selects the control value calculated by one of the normal calculation part  42  and the restrictive calculation part  43  on the basis of a determination result in the PM-PN exhaust determination part  40 . In other words, in a case where it is determined that the operation state of the engine  1  is not the PM-PN exhaust state, the selection part  41  selects the control value calculated by the normal calculation part  42 . On the other hand, in a case where it is determined that the operation state of the engine  1  is the PM-PN exhaust state, the selection part  41  selects the control value calculated by the restrictive calculation part  42 . 
     The actuator regulation part  44  regulates each of the actuators on the basis of the control value calculated by the control value calculation part  46 . The actuator regulation part  44  includes a fuel injection timing •number-of-injections regulation part  44 A, a fuel injection pressure regulation part  44 B, a variable valve timing regulation part  44 C for intake, and a variable valve timing regulation part  44 D for exhaust. The fuel injection timing •number-of-injections regulation part  44 A regulates the fuel injector  16  in such a way that the fuel injection timing and the number of injections are brought into the control values selected by the selection part  41 . Further, the fuel injection pressure regulation part  44 B regulates the high-pressure pump  13  in such a way that the fuel injection pressure is brought into the control value selected by the selection part  41 . Still further, the variable valve timing regulation part  44 C for intake regulates the variable valve timing regulation mechanism  30  in such a way that the valve timing of the intake valve  28  is brought into the control value selected by the selection part  41 . Still further, the variable valve timing regulation part  44 D for exhaust regulates the variable valve timing regulation mechanism  31  in such a way that the valve timing of the exhaust valve  29  is brought into the control value selected by the selection part  41 . 
     Next, a control of the engine  1  by the ECU  24  will be described with reference to  FIG. 3  to  FIG. 13 . In this regard, in the following description, for simplicity, it will be described that also processing which is performed, when described in detail, by the PM-PN exhaust determination part  40  and the like of the ECU  24  is performed by the ECU  24 . 
     The ECU  24  performs the processing according to a base routine shown in  FIG. 3 . When an ignition switch of the vehicle is turned on, the ECU  24  performs initializing processing before performing the base routine. In the initializing processing, the ECU  24  sets “0” to a PM-PN exhaust state flag “xpn”, which will be described later, and to a calculated value. 
     First, in step S 101 , the ECU  24  determines on the basis of values of the accelerator opening and the fuel injection quantity whether or not the operation state of the engine  1  is the PM-PN exhaust state. 
     [PM-PN Exhaust Determination] 
     A determination whether or not the operation state of the engine  1  is the PM-PN exhaust state will be described with reference to  FIG. 4  and  FIG. 5 .  FIG. 4  shows a subroutine for a determination in step S 101  of the base routine. The ECU  24  repeatedly performs the present subroutine at a specified period (for example, at a period of 10 ms). Further,  FIG. 5  shows operation states of the vehicle and the engine  1  and here shows an example in a case where the vehicle traveling at a constant speed accelerates on the way and then again travels at a constant speed. 
     First, the ECU  24  reads the engine speed Ne, an engine load “ce”, accelerator openings accele [i, i−5] of this period and five periods ago, fuel injection quantities [i, i−5] of this period and five periods ago, and a PM-PN exhaust state flag xpn[i−1] of one period ago of the engine  1 . In the following description, the number of revolutions Ne and the load “ce” of the engine  1  will be referred to as “an engine speed Ne” and “an engine load ce”, respectively. 
     Next, in step S 202 , the ECU  24  determines whether or not the engine speed Ne is within a predetermined range (α≦Ne≦β). In a case where the engine speed Ne is within the predetermined range (S 202 : YES), the ECU  24  proceeds to step S 203 . 
     Next, in step S 203 , the ECU  24  determines whether or not the engine load “ce” is within a predetermined range (γ≦ce≦δ). In a case where the engine load “ce” is within the predetermined range (S 203 : YES), the ECU  24  proceeds to step S 205 . 
     Next, in step S 205 , the ECU  24  calculates an accelerator opening variation daccele from 5 periods ago to the present period. After the ECU  24  calculates the accelerator opening variation daccele, the ECU  24  proceeds to step S 206 . 
     Next, in step S 206 , the ECU  24  calculates a fuel injection quantity variation dquantity from 5 periods ago to the present period. After the ECU  24  calculates the fuel injection quantity variation dquantity, the ECU  24  proceeds to step S 207 . 
     Next, in step S 207 , the ECU  24  determines whether or not “0” is set to the PM-PN exhaust state flag xpn[i−1] of one period ago. Here, in a case where “0” is set to the PM-PN exhaust state flag “xpn” of one period ago, it is shown that the engine  1  is not in the PM-PN exhaust state. On the other hand, in a case where “1” is set to the PM-PN exhaust state flag “xpn” of one period ago, it is shown that the engine  1  is in the PM-PN exhaust state. In a case where “0” is set to the PM-PN exhaust state flag xpn[i−1] of one period ago and where it is hence determined that the engine  1  is not in the PM-PN exhaust state, the ECU  24  proceeds to step S 208 . 
     Next, in step S 208 , the ECU  24  determines whether or not the accelerator opening variation daccele is a threshold value ε or more. In a case where a driver of the vehicle presses down the accelerator pedal  26  so as to accelerate the vehicle and where, as shown at a time t 1  of  FIG. 5 , the accelerator opening variation daccele is the threshold value ε or more (S 208 : YES), the ECU  24  proceeds to step S 209 . 
     Next, in step S 209 , the ECU  24  sets “1” to the PM-PN exhaust state flag “xpn”. By a fact that the accelerator opening variation daccele is the threshold values or more, it can be determined that the vehicle starts an accelerating state and hence it can be predicted that a particulate matter to be discharged will be increased. Hence, “1”, which shows that the operation state of the engine  1  is the PM-PN exhaust state, is set to the PM-PN exhaust state flag “xpn”. 
     In this way, it is determined on the basis of the accelerator opening variation daccele that the vehicle starts the acceleration state, so that it is possible to quickly detect that the vehicle is brought into the acceleration state and to reflect that the vehicle is brought into the acceleration state to the processing. There is caused a time lag from a time when the driver of the vehicle presses down the accelerator pedal  26  to a time when each of the actuators such as the high-pressure pump  13  starts to operate in response to this. By determining that the vehicle starts the acceleration state on the basis of the accelerator opening variation daccele, it is possible to eliminate the time lag and to quickly detect that the vehicle is brought into the acceleration state. 
     On the other hand, in a case where it is determined in step S 208  that the accelerator opening variation daccele is not the threshold value ε or more (S 208 : NO), the ECU  24  proceeds to step S 210 . 
     Next, in step S 210 , the ECU  24  sets “0” to the PM-PN exhaust state flag “xpn”. The accelerator opening variation daccele is not the threshold value ε or more, so that it can be determined that the vehicle does not start the acceleration state and it can be predicted that the discharged particulate matter is not increased so much. Hence, the ECU  24  sets “0”, which shows the operation state of the engine  1  is not the PM-PN exhaust state, to the PM-PN exhaust state flag “xpn”. 
     In contrast to this, in a case where “0” is not set to the PM-PN exhaust state flag xpn[i−1] of one period ago in step S 207  (S 207 : NO), the ECU  24  proceeds to step S 211 . In this case, “1” is set to the PM-PN exhaust state flag xpn[i−1] of one period ago and the operation state of the engine  1  is the PM-PN exhaust state. In other words, the vehicle is in the acceleration state. 
     Next, in step S 211 , the ECU  24  determines whether or not the fuel injection quantity variation dquantity is less than a threshold value ζ. In a case where the driver of the vehicle returns the accelerator pedal  26  so as to finish the acceleration state and where, as shown at a time t 2  in  FIG. 5 , the fuel injection quantity variation dquantity becomes less than the threshold value ζ (S 211 : YES), the ECU  24  proceeds to step S 212 . 
     Next, in step S 212 , the ECU  24  sets “0” to the PM-PN exhaust state flag “xpn”. By a fact that the fuel injection quantity variation dquantity becomes less than the threshold value ζ, it can be determined that the vehicle finishes the acceleration state. Hence, the ECU  24  sets “0”, which shows that the operation state of the engine  1  is not the PM-PN exhaust state, to the PM-PN exhaust state flag “xpn”. 
     In this way, by determining that the acceleration state of the vehicle is finished on the basis of the fuel injection quantity variation dquantity, it is possible to correctly detect that the acceleration state of the vehicle is finished and to reflect that the acceleration state of the vehicle is finished to the processing. There is caused a time lag from a time when the driver of the vehicle returns the accelerator pedal  26  to a time when a quantity of the fuel injected from the fuel injector  16  is changed in response to this. By determining that the vehicle finishes the acceleration state on the basis of the fuel injection quantity variation dquantity, it is possible to correctly detect a timing when the quantity of the fuel injected from the fuel injector  16  is actually changed and when the vehicle finishes the acceleration state. 
     On the other hand, in a case where it is determined in step S 211  that the fuel injection quantity variation dquantity is not less than the threshold value ζ (S 211 : NO), the ECU  24  proceeds to step S 213 . 
     Next, in step S 213 , the ECU  24  sets “1” to the PM-PN exhaust state flag “xpn”. By a fact that the fuel injection quantity variation dquantity is not less than the threshold value C, it can be determined that the vehicle continues the acceleration state. Hence, the ECU  24  sets “1”, which shows the operation state of the engine  1  is the PM-PN exhaust state, to the PM-PN exhaust state flag “xpn”. 
     Here, in a case where it is determined in step S 202  that the engine speed Ne is not within the predetermined range (α≦Ne≦β) (S 202 : NO) or in a case where it is determined in step S 203  that the engine load “ce” is not within the predetermined range (γ≦ce≦δ) (S 203 : NO), the ECU  24  proceeds to step S 214 . 
     Next, in step S 214 , the ECU  24  sets “0” to the PM-PN exhaust state flag “xpn”. When processing for restricting the PM-PN exhaust, which will be described later, is performed even in a case where the engine speed Ne and the engine load “ce” are not within the predetermined ranges respectively set for them, a significant decrease in the output of the engine  1  is likely to be caused. In order to avoid this problem, in a case where the engine speed Ne and the engine load “ce” are not within the predetermined ranges respectively set for them, the ECU  24  sets “0” to the PM-PN exhaust state flag “xpn” and does not perform the processing for restricting the PM-PN exhaust. 
     Returning to  FIG. 3 , the description will be continuously made. The ECU  24  having finished the processing of step S 101  determines in step S 102  whether or not the operation state of the engine  1  is the PM-PN exhaust state. Specifically, the ECU  24  determines whether or not the “1” is set to the PM-PN exhaust state flag “xpn”. In a case where the operation state of the engine  1  is the PM-PN exhaust state, the ECU  24  proceeds to step S 103 . 
     [In-Cylinder State Estimation] 
     Next, in step S 103 , the ECU  24  makes an estimation of a state in the cylinder  50 . The estimation is made so as to perform a restrictive control of the PM-PN suitable for the state in the cylinder  50  in a later step. The estimation will be described in detail with reference to  FIG. 6  to  FIG. 8 .  FIG. 6  shows a subroutine for an in-cylinder state estimation in step S 103  of the base routine. The ECU  24  repeatedly performs the present subroutine at a predetermined period (for example, at a period of 10 ms). 
     First, in step S 301  of  FIG. 6 , the ECU  24  reads the engine speed Ne, the engine load “ce”, and a coolant temperature “thw” of the engine  1 . In the following description, the coolant temperature “thw” of the engine  1  is referred to as “an engine coolant temperature “thw”. 
     Next, in step S 302 , the ECU  24  determines whether or not the engine coolant temperature “thw” is a threshold value η or less. In a case where the engine coolant temperature “thw” is the threshold value η or less (S 302 : YES), the ECU  24  proceeds to step S 303 . 
     Next, in step S 303 , the ECU  24  estimates the state in the cylinder  50  on the basis of a cold map. 
     The cold map is a map stored in a ROM built in the ECU  24  and, as shown in  FIG. 7 , has the engine speed Ne and the engine load “ce” as coordinates axes. In the cold map, a range where the engine speed Ne is α≦Ne≦β and where the engine load “ce” is γ≦ce≦δ is divided into three sections. The PM-PN generation states of “the WET state”, “the nonuniform state”, and “the high temperature state” are specified in the respective sections. As described above, these three PM-PN generation states are states different from each other in a cause of generating the particulate matter. 
     In a case where the engine coolant temperature “thw” is the threshold value η or less, the ECU  24  compares the engine speed Ne and the engine load “ce”, which have been read in step S 301 , with the cold map, thereby estimating the state in the cylinder  50 . Specifically, the ECU  24  specifies which of “the WET state”, “the nonuniform state”, and “the high temperature state”, a combination of the engine speed Ne and the engine load “ce” belongs to. 
     On the other hand, in a case where it is determined in step S 302  that the engine coolant temperature “thw” is not the threshold value η or less, the ECU  24  proceeds to step S 304 . 
     Next, in step S 304 , the ECU  24  estimates the state in the cylinder  50  on the basis of a hot map. 
     The hot map, similarly to the cold map, is a map stored in the ROM built in the ECU  24  and, as shown in  FIG. 8 , has the engine speed Ne and the engine load “ce” as the coordinates axes. In the hot map, the range where the engine speed Ne is α≦Ne≦β and where the engine load “ce” is γ≦ce≦δ is also divided into three PM-PN generation states of “the WET state”, “the nonuniform state”, and “the high temperature state”, which is similar to the cold map. 
     The hot map is different from the cold map in a range where each of “the WET state”, “the nonuniform state”, and “the high temperature state” occupies. Specifically, in the cold map, a range where the engine speed Ne is α≦Ne≦Ne 1  is specified to be “the WET state”, whereas in the hot map, a range where the engine speed Ne is α≦Ne≦Ne 2 , which is narrower than the cold map, is specified to be “the WET state”. This is because of the following reason: in a state where the engine coolant temperature “thw” is high and where the temperature in the cylinder  50  is also high, it is little concerned that the fuel exists in a liquid state, so that a range of “the WET state” is also specified to be narrow. 
     Further, in the cold map, a range where the engine load “ce” is ce 1 ≦ce≦δ is specified to be “the hot temperature state”, whereas in the hot map, a range where the load “ce” is ce 2 ≦ce≦δ, which is wider than the cold map, is specified to be “the hot temperature state”. This is because of the following reason: in a state where the engine coolant temperature “thw” is high, it is concerned that the temperature in the cylinder  50  is increased excessively, so that a range of “the hot temperature state” is also specified to be wide. 
     In a case where the engine coolant temperature “thw” is not the threshold value η or less, the ECU  24  compares the engine speed Ne and the engine load “ce”, which have been read in S 301 , with the hot map, thereby estimating the state in the cylinder  50 . Specifically, the ECU  24  specifies which of “the WET state”, “the nonuniform state”, and “the high temperature state”, a combination of the engine speed Ne and the engine load “ce” belongs to. 
     Here, in the present embodiment, the ECU  24  estimates the state in the cylinder  50  on the basis of the engine speed Ne, the engine load “ce”, and the engine coolant temperature “thw”, but the present disclosure is not limited to these. In other words, the ECU  24  may estimate the state in the cylinder  50  on the basis of at least one of the engine coolant temperature “thw”, the engine speed Ne, the engine load “ce”, the intake air quantity, the throttle opening, the accelerator opening, the vehicle speed, the fuel injection quantity, and other temperature in the engine  1 . 
     Returning to  FIG. 3 , the description will be continuously made. The ECU  24  having finished the processing of step S 103  proceeds to step S 104 . 
     [Actuator Control Value Calculation for an Restrictive Control of PM-PN] 
     Next, in step S 104 , the ECU  24  calculates an actuator control value for a restrictive control of PM-PN. A calculation of the control value will be described with reference to  FIG. 9 .  FIG. 9  shows a subroutine for calculating a control value for a restrictive control of PM-PN in step S 104  of the base routine. 
     First, in step S 401  of  FIG. 9 , the ECU  24  reads the state estimated by estimating the state in the cylinder  50 , the engine speed Ne, the engine load “ce”, and the engine coolant temperature “thw”. After the ECU  24  reads these values, the ECU  24  proceeds to step S 402 . 
     Next, in step S 402 , the ECU  24  determines whether or not the state in the cylinder  50  is “the WET state”. In a case where it is determined that the state in the cylinder  50  is “the WET state” (S 402 : YES), the ECU  24  proceeds to step S 404 . 
     Next, in step S 404 , the ECU  24  calculates the control value of each actuator on the basis of a control value map corresponding to “the WET state”. In the present embodiment, the control value map which has the engine speed Ne and the engine load “ce” as coordinate axes and which is used for calculating a fuel injection timing, a fuel injection pressure, an intake valve timing, and an exhaust valve timing, which are suitable for eliminating “the WET state”, is stored in the ROM of the ECU  24 . The ECU  24  calculates control values for controlling the respective actuators of the fuel injector  16 , the high-pressure pump  13 , and the variable valve timing mechanisms  30 ,  31  on the basis of the control value map corresponding to “the WET state”. 
     On the other hand, in a case where it is determined in step S 402  that the state in the cylinder  50  is not “the WET state” (S 402 : NO), the ECU  24  proceeds to step S 403 . 
     Next, in step S 403 , the ECU  24  determines whether or not the state in the cylinder  50  is “the nonuniform state”. In a case where the state in the cylinder  50  is “the nonuniform state” (S 403 : YES), the ECU  24  proceeds to step S 405 . 
     Next, in step S 405 , the ECU  24  calculates the control value of each actuator on the basis of a control value map corresponding to “the nonuniform state”. In the present embodiment, a control value map which has the engine speed Ne and the engine load “ce” as the coordinate axes and which is used for calculating a fuel injection timing, a fuel injection pressure, an intake valve timing, and an exhaust valve timing, which are suitable for eliminating “the nonuniform state”, is stored in the ROM of the ECU  24 . The ECU  24  calculates control values for controlling the respective actuators of the fuel injector  16 , the high-pressure pump  13 , and the variable valve timing mechanisms  30 ,  31  on the basis of the control value map corresponding to “the nonuniform state”. 
     On the other hand, in a case where it is determined in step S 403  that the state in the cylinder  50  is not “the WET state” (S 403 : NO), that is, in a case where the state in the cylinder  50  is “the high temperature state”, the ECU  24  proceeds to step S 406 . 
     Next, in step S 406 , the ECU  24  calculates the control value of each actuator on the basis of a control value map corresponding to “the high temperature state”. In the present embodiment, a control value map which has the engine speed Ne and the engine load “ce” as the coordinate axes and which is used for calculating a fuel injection timing, a fuel injection pressure, an intake valve timing, and an exhaust valve timing, which are suitable for eliminating “the high temperature state”, is stored in the ROM of the ECU  24 . The ECU  24  calculates control values for controlling the respective actuators of the fuel injector  16 , the high-pressure pump  13 , and the variable valve timing mechanisms  30 ,  31  on the basis of the control value map corresponding to “the high temperature state”. 
     Returning to  FIG. 3 , the description will be continuously made. The ECU  24  having finished the processing of step S 104  proceeds to step S 105 . 
     Next, in step S 105 , the ECU  24  controls the respective actuators of the fuel injector  16 , the high-pressure pump  13 , and the variable valve timing mechanisms  30 ,  31  in such a way that the respective actuators are brought into the control values calculated in step S 104 . 
     On the other hand, in a case where it is determined in step S 102  that the operation state of the engine  1  is not the PM-PN exhaust state (S 102 : NO), the ECU  24  proceeds to step S 106 . 
     Next, in step S 106 , the ECU  24  calculates an actuator control value for the normal control. The actuator control value is used for controlling each of the actuators of the fuel injector  16 , the high-pressure pump  13 , and the variable valve timing mechanisms  30 ,  31  in a case where the PM-PN exhaust is not especially restricted. The ECU  24  having finished the processing of step S 106  proceeds to step S 105  and controls the respective actuators. 
     Next, an example of processing performed by the ECU  24  will be described with reference to  FIG. 10  to  FIG. 12 . First, the processing in a case where it is estimated that the state in the cylinder  50  is “the WET state” will be described with reference to  FIG. 10 . 
     [Case where the State in the Cylinder is Estimated to be “the WET State”] 
     In this case, when the operation state of the engine  1  is brought into the PM-PN exhaust state at a time t 3  and “1” is set to the PM-PN exhaust flag “xpn”, the ECU  24  changes the fuel injection timing to a retard side. In this way, a distance between the fuel injector  16  and the piston  56  at the time of a fuel injection is made large, which can restrict the injected fuel being attached to the piston  56  as it is liquid. 
     Further, the ECU  24  controls the high-pressure pump  13  in such a way that the fuel injection pressure is reduced. In this way, it is possible to restrict a flowing of the fuel injected from the fuel injector  16  through the combustion chamber  54  of the cylinder  50  and an adhesion of the fuel to the piston  56  as it is liquid. 
     Still further, the ECU  24  performs an internal exhaust gas recirculation (EGR) in which the high-temperature exhaust gas discharged from the cylinder  50  is made to flow into the intake port  51  in an exhaust stroke of the engine  1  and in which the high-temperature exhaust gas is made to return into the cylinder  50  in an intake stroke of the engine  1 . Specifically, the ECU  24  regulates the variable valve timing mechanisms  30 ,  31  in such a way that the valve timing of the intake valve  28  is changed to an advance side and that the valve timing of the exhaust valve  29  is changed to a retard side. In this way, the temperature in the cylinder  50  can be increased, which can hence restrict an existence of the fuel in the cylinder  50  as it is liquid. 
     Still further, the ECU  24  increases the number of injections of the fuel in one intake stroke, thereby also being able to eliminate “the WET state”. In this case, the ECU  24  increases the number of injections of the fuel, which is one in one intake stroke until then, to two after the operation of the engine  1  is brought into the PM-PN exhaust state. In other words, the quantity of the fuel injected per one injection can be reduced, which hence can further restrict an existence of the fuel in the cylinder  50  as it is liquid. 
     Still further, in a case where the ECU  24  increases the number of injections of the fuel in one intake stroke to two, the ECU  24  changes the injection timing of a first injection to a little advance side whereas the ECU  24  changes the injection timing of a second injection greatly to a retard side. In this way, it is possible to restrict the adhesion of the fuel injected from the fuel injector  16  to the piston  56  as it is liquid. 
     When the operation state of the engine  1  ceases to be the PM-PN exhaust state at a time t 4  and “0” is set to the PM-PN exhaust flag “xpn”, the ECU  24  returns the control values of the respective actuators to those of the normal control. 
     [Case where the State in the Cylinder is Estimated to be “the Nonuniform State”] 
     Next, processing in a case where the state in the cylinder  50  is estimated to be “the nonuniform state” will be described with reference to  FIG. 11 . In this case, when the operation state of the engine  1  is brought into the PM-PN exhaust state at a time t 5  and “1” is set to the PM-PN exhaust flag “xpn”, the ECU  24  changes the fuel injection timing to an advance side. In this way, it is possible to secure a period of time in which the fuel is sufficiently atomized and in which the fuel and the air can be sufficiently mixed with each other between the injection of the fuel and the ignition of the fuel. Hence, it is possible to restrict the nonuniform of the fuel in the cylinder  50 . 
     Further, the ECU  24  controls the high-pressure pump  13  in such a way that the fuel injection pressure is increased. In this way, the fuel injected at a high pressure from the fuel injector  16  can be reduced in a particle diameter and hence can be easily atomized. Hence, it is possible to restrict the nonuniform concentration of the fuel in the cylinder  50 . 
     Still further, as is the case where the state in the cylinder  50  is estimated to be “the WET state”, the ECU  24  makes the engine  1  perform the internal EGR. Specifically, the ECU  24  regulates the variable valve timing mechanisms  30 ,  31  in such a way that the valve timing of the intake valve  28  is changed to the advance side and that the valve timing of the exhaust valve  29  is changed to the retard side. In this way, the temperature in the cylinder  50  can be increased to thereby accelerate the atomization of the fuel, which can hence restrict the nonuniform of the fuel in the cylinder  50 . 
     Still further, as is the case where the state in the cylinder  50  is estimated to be “the WET state”, the ECU  24  increases the number of injections of the fuel, which is one in one intake stroke until then, to two after the operation of the engine  1  is brought into the PM-PN exhaust state. In this way, the diffusion of the fuel injected from the fuel injector  16  can be advanced, which hence can restrict the nonuniform concentration of the fuel in the cylinder  50 . 
     When the operation state of the engine  1  ceases to be the PM-PN exhaust state at a time t 6  and “0” is set to the PM-PN exhaust flag “xpn”, the ECU  24  returns the control values of the respective actuators to those of the normal control. 
     [Case where the State in the Cylinder is Estimated to be “the High Temperature State”] 
     Next, processing in a case where the state in the cylinder  50  is estimated to be “the high temperature state” will be described with reference to  FIG. 12 . In this case, when the operation state of the engine  1  is brought into the PM-PN exhaust state at a time t 7  and “1” is set to the PM-PN exhaust flag “xpn”, the ECU  24  changes the fuel injection timing to the retard side. In this way, the fuel can be injected in a state where a volume of the combustion chamber  54  is large. Hence, heat in the cylinder  50  can be removed by the injected fuel, which can hence reduce the temperature in the cylinder  50 . 
     Further, the ECU  24  controls the high-pressure pump  13  in such a way that the fuel injection pressure is increased. In this way, the fuel injected at a high pressure from the fuel injector  16  can be reduced in a particle diameter and hence can easily remove the heat in the cylinder  50 . Hence, it is possible to reduce the temperature in the cylinder  50 . 
     Still further, the ECU  24  restricts the internal EGR of the engine  1 . Specifically, the ECU  24  regulates the variable valve timing mechanisms  30 ,  31  in such a way that the valve timing of the intake valve  28  is changed to the retard side and that the valve timing of the exhaust valve  29  is changed to the advance side. In this way, the exhaust of the exhaust gas from the interior of the cylinder  50  to the exhaust port  52  side can be advanced, which can hence reduce the temperature in the cylinder  50 . 
     Still further, the ECU  24  increases the number of injections of the fuel in one intake stroke, thereby being able to eliminate “the high temperature state”. In this case, the ECU  24  increases the number of injections of the fuel, which is one in one intake stroke until then, to two after the operation of the engine  1  is brought into the PM-PN exhaust state. In this way, the fuel injected from the fuel injector  16  can be further reduced in the particle diameter and hence can easily remove the heat in the cylinder  50 , which can hence reduce the temperature in the cylinder  50 . 
     When the operation state of the engine  1  ceases to be the PM-PN exhaust state at a time t 8  and “0” is set to the PM-PN exhaust flag “xpn”, the ECU  24  returns the control values of the respective actuators to those of the normal control. 
     The embodiment of the present disclosure has been described above with reference to the specific examples. However, the present disclosure is not limited to these specific examples. In other words, an embodiment in which a person skilled in the art adds an appropriate design change to these specific examples described above is also included in the scope of the present disclosure as far as the embodiment has a feature of the present disclosure. The respective elements, arrangements, materials, conditions, shapes, and sizes included by the respective specific examples described above are not limited to those described above but can be appropriately modified.