JP2009275679A - Intake-air controller for internal combustion engine, and automatic adapting device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake-air controller for an internal combustion engine capable of obtaining the optimum filling efficiency relative to the internal combustion engine provided with a means for varying the filling efficiency of the intake-air. <P>SOLUTION: An adaptation value making intake-air supercharge efficiency the approximately maximum degree is acquired by an automatic adapting device relative to a common rail type diesel engine applied with a variable capacity type turbo-charger in every operation state of the engine while making it as a nozzle vane opening of a variable nozzle vane mechanism, a filling efficiency setting map is memorized in ROM, and the nozzle vane opening of a variable nozzle vane mechanism is controlled according to the filling efficiency setting map. The automatic adapting device varies the nozzle vane opening in the state that a fuel injection amount, a fuel injection pattern and a fuel injection pressure are made constant in every operation state of the engine, and automatically obtains the nozzle vane opening at the time when the intake-air supercharge efficiency becomes approximately maximum as the adaptation value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an intake control device for an internal combustion engine typified by a vehicular diesel engine, and an automatic adaptation device for an internal combustion engine for obtaining a compatible value as a control value of the intake control device. In particular, the present invention relates to a measure for optimizing the charging efficiency in a device provided with means for changing the charging efficiency of intake air into a cylinder.

  As is well known in the art, diesel engines used as automobile engines (hereinafter sometimes referred to simply as engines) have various engine characteristics such as exhaust gas characteristics, fuel consumption characteristics, stable combustion characteristics, and power performance. Complex control is performed to meet the requirements.

  Specifically, the control map is set in advance with a suitable value for each control parameter such as the optimal fuel injection amount according to the engine operating state determined based on the engine speed and load. Is stored in an electronic control unit (engine ECU). The engine ECU controls the engine while referring to the matching value on the control map.

In recent years, as a kind of turbocharger applied to a diesel engine or the like, for example, as disclosed in the following Patent Document 1 and Patent Document 2, a variable displacement turbocharger having a variable capacity turbine side is known. ing. In this type of turbocharger, a nozzle vane (also referred to as a movable vane) having a variable flow area (throat area) of the exhaust gas flow path is disposed in the exhaust gas flow path of the turbine housing. And, for example, by rotating the nozzle vane when the engine is running at a low speed to reduce the flow passage area, the flow velocity of the exhaust gas is increased, so that a high boost pressure can be obtained from the engine low speed range. It has become.
Japanese Patent Laid-Open No. 9-329032 JP 2001-82158 A

  In an engine to which the variable displacement turbocharger as described above is applied, when determining the opening degree of the nozzle vane, similarly to the case described above, an appropriate value of the nozzle vane opening degree is obtained in advance and the engine operating state is determined. Accordingly, the nozzle vane opening degree is set according to the above-mentioned conforming value.

  In general, as a method for obtaining an appropriate value for the nozzle vane opening, that is, a method for obtaining an appropriate value for the intake charging efficiency, the fuel injection amount from the injector is generally maintained while maintaining the engine speed constant. The maximum torque point of the engine was obtained while alternately increasing the supercharging amount and the supercharging amount, and the nozzle vane opening for obtaining the supercharging amount for which the maximum torque point was obtained was obtained as an appropriate value.

  However, in such a method for obtaining the optimum value of the charging efficiency, even if the nozzle vane opening is set with the optimum value obtained by the above-described adaptation operation as a target value, there is no guarantee that the supercharging efficiency of the intake air will be the highest efficiency. There wasn't. In other words, when determining the appropriate value of the nozzle vane opening, the amount of fuel injected from the injector is also increased. Therefore, before and after changing the nozzle vane opening to determine the appropriate value, engine operation other than this nozzle vane opening is performed. The condition (fuel injection amount which is one of the control parameters) is different. For this reason, since the appropriate value is obtained by changing the nozzle vane opening degree under different conditions, the possibility that the appropriate value becomes the optimum value is low.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an internal combustion engine capable of obtaining an optimal charging efficiency with respect to an internal combustion engine having means for changing the charging efficiency of intake air. It is to provide an intake control device and an automatic adaptation device.

-Solving principle-
The solution principle of the present invention taken in order to achieve the above object is to obtain the intake charging efficiency at which the supercharging efficiency of the internal combustion engine is maximized in a state where control parameters other than the intake charging efficiency are fixed. A control operation (supercharger control operation) is performed so as to obtain efficiency.

-Solution-
Specifically, the present invention is premised on an intake control device for an internal combustion engine provided with a charging efficiency variable means for changing the charging efficiency of intake air supplied toward the cylinder of the internal combustion engine. With respect to the intake control device of the internal combustion engine, the intake efficiency set by the charge efficiency variable means is changed while the fuel injection amount, fuel injection pattern, and fuel injection pressure into the cylinder are substantially constant. Storage means for storing the control value of the charging efficiency variable means, which is obtained in advance for each of a plurality of operating states of the internal combustion engine and at which the intake supercharging efficiency becomes substantially maximum, and during operation of the internal combustion engine, A control unit that reads out a control value corresponding to the operation state from the storage unit and uses the control value as a target value to control the charging efficiency variable unit;

  Due to this specific matter, when setting the charging efficiency of the intake air by controlling the charging efficiency variable means during operation of the internal combustion engine, the control value (conformity) of the charging efficiency variable means determined in advance for each operating state of the internal combustion engine is set. Value), the charging efficiency variable means is controlled using a control value corresponding to the current operating state of the internal combustion engine as a target value. Then, the control value of the charging efficiency variable means that is obtained in advance is the above in a state where the fuel injection amount, the fuel injection pattern, and the fuel injection pressure into the cylinder are substantially constant for each operating state of the internal combustion engine. It is calculated | required by changing the filling efficiency set by the filling efficiency variable means. For this reason, the control value (adapted value) of the charging efficiency variable means obtained in advance is appropriately obtained as the maximum efficiency of the operation efficiency of the internal combustion engine, and this control value is targeted. By controlling the charging efficiency variable means, the intake supercharging efficiency can be maintained at a substantially maximum.

  Specific configurations of the charging efficiency variable means and the charging efficiency control means include the following. First, the charging efficiency variable means is provided in the supercharger and changes the flow area of the gas flowing toward the turbine wheel by changing the opening degree of the nozzle vane that can be opened and closed by the variable nozzle vane mechanism. Thus, the charging efficiency of intake air is changed by changing the supercharging pressure. Further, the charging efficiency control means is configured to control the variable nozzle vane mechanism so as to set the opening degree of the nozzle vane with the control value corresponding to the operation state as a target value during the operation of the internal combustion engine.

  In this configuration, when obtaining the control value of the charging efficiency variable means (appropriate value of the nozzle vane opening), the amount of fuel injected into the cylinder, the fuel injection pattern, and the fuel injection pressure are approximately set for each operating state of the internal combustion engine. In a fixed state, while controlling the variable nozzle vane mechanism to change the opening degree of the nozzle vane, the opening degree of the nozzle vane that obtains the charging efficiency at which the intake supercharging efficiency becomes substantially maximum is acquired. For example, the nozzle vane opening at which the intake supercharging efficiency is maximized is acquired as an appropriate value while gradually decreasing the nozzle vane opening to increase the charging efficiency.

  Examples of the configuration of the automatic adaptation device for automatically acquiring the control value of the charging efficiency variable means that can obtain the charging efficiency at which the intake supercharging efficiency is substantially maximized include the following. First, for an internal combustion engine provided with a charging efficiency variable means for changing the charging efficiency of the intake air supplied toward the cylinder, an intake air excess control is performed as a control value for the charging efficiency variable means for each operating state of the internal combustion engine. An automatic adapting device for obtaining a conforming value that maximizes the feeding efficiency is assumed. For this automatic adaptation device, the charging efficiency variable means sets the fuel injection amount into the cylinder, the fuel injection pattern, and the fuel injection pressure in a substantially constant state for each of a plurality of operating states of the internal combustion engine. The intake charging efficiency is changed, and the control value of the charging efficiency variable means at the time when the intake supercharging efficiency becomes substantially maximum is automatically acquired as the adaptive value in the operating state.

  This makes it possible to automatically acquire a calibration value that can maintain the intake supercharging efficiency at a substantially maximum, and to acquire an appropriate calibration value by trial and error, or to acquire the calibration value enormously. This eliminates the need for time, improving the efficiency of the adaptation operation and improving the reliability of the adaptation value.

  Examples of the configuration for controlling the operation of the internal combustion engine using the control value (adapted value) acquired by the automatic adapting device as described above include the following. That is, it is premised on an intake control device for an internal combustion engine provided with a charging efficiency variable means for changing the charging efficiency of intake air supplied toward the cylinder of the internal combustion engine. With respect to the intake control device for the internal combustion engine, the charging efficiency variable means in the state where the fuel injection amount, the fuel injection pattern, and the fuel injection pressure into the cylinder are substantially constant for each of a plurality of operating states of the internal combustion engine. Automatic adaptation that changes the charging efficiency of the intake air that is set, and automatically acquires the control value of the charging efficiency variable means at the time when the intake supercharging efficiency becomes approximately maximum as the appropriate value in the operating state Storage means for storing each adaptive value obtained by the apparatus, and when the internal combustion engine is operated, the adaptive value corresponding to the operating state is read from the storage means, and the charging efficiency variable means is set with the adaptive value as a target value. Charging efficiency control means for controlling.

  Thereby, the operation of the internal combustion engine can be controlled by effectively using the adaptation value acquired by the automatic adaptation device, and the practicality of the present invention can be improved.

  The present invention relates to controlling the charging efficiency variable means for varying the charging efficiency of the intake air of the internal combustion engine, and the intake charging efficiency that maximizes the supercharging efficiency of the internal combustion engine in a state where control parameters other than the intake charging efficiency are fixed. Therefore, the control operation can be executed so as to obtain the intake charge efficiency. For this reason, it is possible to maintain the intake supercharging efficiency substantially at the maximum regardless of the operating state of the internal combustion engine.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a case where the present invention is applied to a common rail in-cylinder direct injection multi-cylinder (for example, in-line 4-cylinder) diesel engine (compression self-ignition internal combustion engine) mounted on an automobile will be described.

-Engine configuration-
First, a schematic configuration of a diesel engine (hereinafter simply referred to as an engine) according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram of an engine 1 and its control system according to the present embodiment. FIG. 2 is a cross-sectional view showing the combustion chamber 3 of the diesel engine and its periphery.

  As shown in FIG. 1, the engine 1 according to the present embodiment is configured as a diesel engine system having a fuel supply system 2, a combustion chamber 3, an intake system 6, an exhaust system 7 and the like as main parts.

  The fuel supply system 2 includes a supply pump 21, a common rail 22, an injector (fuel injection valve) 23, a shutoff valve 24, a fuel addition valve 26, an engine fuel passage 27, an addition fuel passage 28, and the like.

  The supply pump 21 pumps fuel from the fuel tank, makes the pumped fuel high pressure, and supplies it to the common rail 22 via the engine fuel passage 27. The common rail 22 has a function as a pressure accumulation chamber that holds (accumulates) the high-pressure fuel supplied from the supply pump 21 at a predetermined pressure, and distributes the accumulated fuel to the injectors 23. The injector 23 includes a piezoelectric element (piezo element) therein, and is configured by a piezo injector that is appropriately opened to supply fuel into the combustion chamber 3. Details of the fuel injection control from the injector 23 will be described later.

  The supply pump 21 supplies a part of the fuel pumped from the fuel tank to the fuel addition valve 26 via the addition fuel passage 28. The added fuel passage 28 is provided with the shutoff valve 24 for shutting off the added fuel passage 28 and stopping fuel addition in an emergency.

  The fuel addition valve 26 is configured so that the fuel addition amount to the exhaust system 7 becomes a target addition amount (addition amount that makes the exhaust A / F become the target A / F) by an addition control operation by the ECU 100 described later. In addition, it is constituted by an electronically controlled on-off valve whose valve opening timing is controlled so that the fuel addition timing becomes a predetermined timing. That is, a desired fuel is injected and supplied from the fuel addition valve 26 to the exhaust system 7 (from the exhaust port 71 to the exhaust manifold 72) at an appropriate timing.

  The intake system 6 includes an intake manifold 63 connected to an intake port 15a formed in the cylinder head 15 (see FIG. 2), and an intake pipe 64 that constitutes an intake passage is connected to the intake manifold 63. Further, an air cleaner 65, an air flow meter 43, and a throttle valve 62 are arranged in this intake passage in order from the upstream side. The air flow meter 43 outputs an electrical signal corresponding to the amount of air flowing into the intake passage via the air cleaner 65.

  The exhaust system 7 includes an exhaust manifold 72 connected to an exhaust port 71 formed in the cylinder head 15, and exhaust pipes 73 and 74 constituting an exhaust passage are connected to the exhaust manifold 72. In addition, a maniverter (exhaust gas purification device) 77 including a NOx storage catalyst (NSR catalyst: NOx Storage Reduction catalyst) 75 and a DPNR catalyst (Diesel Particle-NOx Reduction catalyst) 76, which will be described later, is disposed in the exhaust passage. Yes. Hereinafter, the NSR catalyst 75 and the DPNR catalyst 76 will be described.

The NSR catalyst 75 is an NOx storage reduction catalyst. For example, alumina (Al ₂ O ₃ ) is used as a support, and potassium (K), sodium (Na), lithium (Li), cesium (Cs), for example, is supported on this support. Alkali metal such as barium (Ba), alkaline earth such as calcium (Ca), rare earth such as lanthanum (La) and yttrium (Y), and noble metal such as platinum (Pt) were supported. It has a configuration.

The NSR catalyst 75 occludes NOx in a state where a large amount of oxygen is present in the exhaust gas, has a low oxygen concentration in the exhaust gas, and a large amount of reducing component (for example, an unburned component (HC) of the fuel). In the existing state, NOx is reduced to NO ₂ or NO and released. NO NOx released as NO ₂ or NO, the N ₂ is further reduced due to quickly reacting with HC or CO in the exhaust. Further, HC and CO are oxidized to H ₂ O and CO ₂ by reducing NO ₂ and NO. That is, by appropriately adjusting the oxygen concentration and HC component in the exhaust gas introduced into the NSR catalyst 75, HC, CO, and NOx in the exhaust gas can be purified. In the present embodiment, the oxygen concentration and HC component in the exhaust gas can be adjusted by the fuel addition operation from the fuel addition valve 26.

  On the other hand, the DPNR catalyst 76 is, for example, a porous ceramic structure carrying a NOx storage reduction catalyst, and PM in the exhaust gas is collected when passing through the porous wall. Further, when the air-fuel ratio of the exhaust gas is lean, NOx in the exhaust gas is stored in the NOx storage reduction catalyst, and when the air-fuel ratio becomes rich, the stored NOx is reduced and released. Further, the DPNR catalyst 76 carries a catalyst that oxidizes and burns the collected PM (for example, an oxidation catalyst mainly composed of a noble metal such as platinum).

  Here, the structure of the combustion chamber 3 of a diesel engine and its peripheral part is demonstrated using FIG. As shown in FIG. 2, a cylinder block 11 constituting a part of the engine body is formed with a cylindrical cylinder bore 12 for each cylinder (four cylinders), and a piston 13 is formed inside each cylinder bore 12. Is accommodated so as to be slidable in the vertical direction.

  The combustion chamber 3 is formed above the top surface 13 a of the piston 13. That is, the combustion chamber 3 is defined by the lower surface of the cylinder head 15 attached to the upper portion of the cylinder block 11 via the gasket 14, the inner wall surface of the cylinder bore 12, and the top surface 13 a of the piston 13. A cavity 13 b is formed in a substantially central portion of the top surface 13 a of the piston 13, and this cavity 13 b also constitutes a part of the combustion chamber 3.

  The piston 13 has a small end portion 18a of a connecting rod 18 connected by a piston pin 13c, and a large end portion of the connecting rod 18 is connected to a crankshaft that is an engine output shaft. As a result, the reciprocating movement of the piston 13 in the cylinder bore 12 is transmitted to the crankshaft via the connecting rod 18, and the engine output is obtained by rotating the crankshaft. Further, a glow plug 19 is disposed toward the combustion chamber 3. The glow plug 19 functions as a start-up assisting device that is heated red when an electric current is applied immediately before the engine 1 is started and a part of the fuel spray is blown onto the glow plug 19 to promote ignition and combustion.

  The cylinder head 15 is formed with the intake port 15a for introducing air into the combustion chamber 3 and the exhaust port 71 for exhausting exhaust gas from the combustion chamber 3, and intake air for opening and closing the intake port 15a. An exhaust valve 17 that opens and closes the valve 16 and the exhaust port 71 is provided. The intake valve 16 and the exhaust valve 17 are disposed to face each other with the cylinder center line P interposed therebetween. That is, the engine 1 is configured as a cross flow type. The cylinder head 15 is provided with the injector 23 that directly injects fuel into the combustion chamber 3. The injector 23 is disposed at a substantially upper center of the combustion chamber 3 in a standing posture along the cylinder center line P, and injects fuel introduced from the common rail 22 toward the combustion chamber 3 at a predetermined timing. It has become.

  Furthermore, as shown in FIG. 1, the engine 1 is provided with a supercharger (turbocharger) 5. The turbocharger 5 includes a turbine wheel 52c and a compressor wheel 52b that are connected via a turbine shaft 52a. The compressor wheel 52b is disposed facing the inside of the intake pipe 64, and the turbine wheel 52c is disposed facing the inside of the exhaust pipe 73. For this reason, the turbocharger 5 performs a so-called supercharging operation in which the compressor wheel 52b is rotated using the exhaust flow (exhaust pressure) received by the turbine wheel 52c to increase the intake pressure. The turbocharger 5 in this embodiment is a variable nozzle type (variable capacity type) turbocharger, and is provided with a variable nozzle vane mechanism (not shown in FIG. 1) on the turbine wheel 52c side. The variable nozzle vane mechanism is opened. By adjusting the degree, the supercharging pressure of the engine 1 can be adjusted. A specific configuration of the variable nozzle vane mechanism will be described later.

  An intake pipe 64 of the intake system 6 is provided with an intercooler 61 for forcibly cooling the intake air whose temperature has been raised by supercharging in the turbocharger 5. The throttle valve 62 provided further downstream than the intercooler 61 is an electronically controlled on-off valve whose opening degree can be adjusted steplessly. It has a function of narrowing down the area and adjusting (reducing) the supply amount of the intake air.

  Further, the engine 1 is provided with an exhaust gas recirculation passage (EGR passage) 8 that connects the intake system 6 and the exhaust system 7. The EGR passage 8 is configured to reduce the combustion temperature by recirculating a part of the exhaust gas to the intake system 6 and supplying it again to the combustion chamber 3, thereby reducing the amount of NOx generated. In addition, the EGR passage 8 is opened and closed steplessly by electronic control, and the exhaust gas passing through the EGR passage 8 (recirculating) is cooled by an EGR valve 81 that can freely adjust the exhaust flow rate flowing through the passage. An EGR cooler 82 is provided.

-Turbocharger 5-
Next, the turbocharger (variable capacity turbocharger) 5 and the variable nozzle vane mechanism (filling efficiency varying means) 9 provided in the turbocharger 5 will be described.

  FIG. 3 is a cross-sectional view of the turbocharger 5 along the axis of the turbine shaft 52a, and FIG. 4 is an enlarged cross-sectional view of the turbine wheel 52c and its periphery. FIG. 5 is a front view of the variable nozzle vane mechanism 9 (a view of the variable nozzle vane mechanism 9 viewed from the compressor wheel 52b side), and shows a state where the nozzle vane opening is set large. Further, FIG. 6 is a rear view of the variable nozzle vane mechanism 9 (a view of the variable nozzle vane mechanism 9 viewed from the side opposite to the compressor wheel 52b side), and shows a state in which the nozzle vane opening is set large.

  The turbocharger 5 is configured as a variable capacity type (variable nozzle type) turbocharger. As shown in FIG. 3, the turbocharger 5 includes a housing 51, a turbine shaft 52a rotatably accommodated in the housing 51, and the turbine shaft. The compressor wheel 52b attached to one end side (right side in FIG. 3) of 52a and the turbine wheel 52c attached to the other end side (left side in FIG. 3) of the turbine shaft 52a are provided. The turbine shaft 52a, the compressor wheel 52b, and the turbine wheel 52c constitute a turbine 52 that is a rotating body.

  The housing 51 is configured by integrally assembling a compressor housing 51a, a center housing (bearing housing) 51b, and a turbine housing 51c. That is, the compressor housing 51a and the turbine housing 51c are assembled on both sides of the center housing 51b.

  The compressor housing 51a has a shape capable of taking in air from the central portion (axial center portion) and discharging it to the outside.

  The compressor wheel 52b accommodated in the compressor housing 51a is fixed to the turbine shaft 52a by a lock nut 52d, and rotates integrally with the turbine shaft 52a. The compressor wheel 52b is provided with a plurality of compressor blades. When the compressor wheel 52b rotates, the air is accelerated and compressed radially outward by centrifugal force by the compressor blade. For this reason, when air is introduced into the central portion of the compressor housing 51a, the air is compressed by the compressor blades of the rotating compressor wheel 52b, and the compressed air is discharged to the intake pipe 64 toward the intake manifold 63. It has come to be.

  A seal ring collar 52e is disposed adjacent to the compressor wheel 52b. The seal ring collar 52e surrounds the turbine shaft 52a.

  The center housing 51b is disposed at a substantially central portion in the axial direction of the turbocharger 5. The center housing 51b is provided with a thrust bearing 52f. The thrust bearing 52f is a bearing for receiving a load in the thrust direction of the turbine shaft 52a, and is lubricated by oil or the like.

  The center housing 51b is provided with a floating bearing 52g for holding the rotation of the turbine shaft 52a. The floating bearing 52g holds the load in the radial direction of the turbine shaft 52a. An oil film is interposed between the floating bearing 52g and the turbine shaft 52a so that the floating bearing 52g does not directly contact the turbine shaft 52a. Further, an oil film is also present between the floating bearing 52g and the center housing 51b so that the floating bearing 52g does not directly contact the center housing 51b. The floating bearing 52g is positioned by a retainer ring 52h.

  Next, the variable nozzle vane mechanism 9 will be described. The variable nozzle vane mechanism 9 is disposed in a link chamber 91 formed between the center housing 51b and the turbine housing 51c.

  The variable nozzle vane mechanism 9 includes a unison ring 92 housed in the link chamber 91 and a plurality of arms 93, 93,... That are located on the inner peripheral side of the unison ring 92 and partially engage with the unison ring 92. (See FIG. 5), a nozzle plate (NV plate) 94 (see FIG. 4) disposed so as to contact the turbine housing 51c in the turbocharger axial direction, and the plurality of arms 93, 93, Are provided with a main arm 95 for driving... And a vane shaft 97 connected to the arm 93 for driving the nozzle vane 96. The vane shaft 97 is rotatably supported by the nozzle plate 94, and each arm 93 and each nozzle vane 96 are connected to each other in an integral manner.

  Further, in the present embodiment, the turbine housing 51c is configured by integrally assembling two members, a main body 51c-a made of cast metal and a plate 51c-b made of sheet metal (see FIG. 4). The weight is reduced.

  A housing plate 51e is attached to the turbine housing 51c. The housing plate 51e is disposed at a position facing the nozzle plate 94, and an arrangement space for the nozzle vane 96 is formed between the housing plate 51e and the nozzle plate 94. That is, an exhaust gas flow path is formed between the nozzle plate 94 and the housing plate 51e, and the nozzle vane 96 is disposed in the flow path. For this reason, the nozzle plate 94 and the housing plate 51 e are disposed on both sides of the nozzle vane 96 in the rotational axis direction so as to face the end face of the nozzle vane 96. The gap between the nozzle plate 94 and the end face of the nozzle vane 96, and the gap between the housing plate 51e and the end face of the nozzle vane 96 (these gaps are referred to as nozzle side clearance) are within a range in which the sliding resistance does not increase. It is preferable to make it as small as possible so that the exhaust gas flows only in the exhaust gas flow path formed between the nozzle vanes 96 and 96 (to reduce the leakage of exhaust gas from the nozzle side clearance).

  The variable nozzle vane mechanism 9 is a mechanism for adjusting the rotation angle (rotation posture) of the plurality of (for example, 12) nozzle vanes 96, 96,... Disposed at equal intervals on the outer peripheral side of the turbine blade. Yes, when the drive link 95a connected to the main arm 95 is rotated by a predetermined angle, the turning force is applied to the main arm 95, the unison ring 92, the arms 93, 93, ..., the vane shafts 97, 97, Are transmitted to the nozzle vanes 96, 96,... Via the nozzle vanes 96, 96,.

  Specifically, the drive link 95a is rotatable around a drive shaft 95b. The drive shaft 95b is pivotally coupled to the drive link 95a and the main arm 95. For this reason, if the drive shaft 95b rotates with the rotation of the drive link 95a, this rotational force is transmitted to the main arm 95. An inner peripheral end of the main arm 95 is fixed to the drive shaft 95 b, and an outer peripheral end is engaged with the unison ring 92. For this reason, when the main arm 95 rotates around the drive shaft 95b, this turning force is transmitted to the unison ring 92. The outer peripheral side ends of the arms 93, 93,... Are fitted to the inner peripheral surface of the unison ring 92. When the unison ring 92 is rotated, this rotational force is transmitted to the arms 93, 93,. Specifically, the unison ring 92 is disposed so as to be slidable in the circumferential direction with respect to the nozzle plate 94, and a plurality of recesses 92a, 92a,. And the end portions on the outer peripheral side of the arms 93, 93,. The arms 93, 93,... Can rotate around the vane shaft 97, and the rotation of the arms 93 is transmitted to the vane shaft 97. Since the vane shaft 97 is connected to the nozzle vane 96, the nozzle vane 96 rotates together with the vane shaft 97 and the arm 93.

  The turbine housing 51c is provided with a turbine housing vortex chamber. Exhaust gas is supplied to the turbine housing vortex chamber, and the flow of the exhaust gas rotates the turbine wheel 52c. At this time, as described above, the rotational positions of the nozzle vanes 96, 96,... Are adjusted, and the rotational angle is set to adjust the flow rate and flow velocity of the exhaust from the turbine housing vortex chamber to the exhaust turbine chamber. It is possible to do. This makes it possible to adjust the supercharging performance. For example, the nozzle vanes 96, 96,... Are reduced so as to reduce the flow area (throat area) between the nozzle vanes 96, 96,. If the rotational position of... Is adjusted, the flow rate of the exhaust gas increases, and a high boost pressure can be obtained from the engine low speed range.

  The drive link 95a of the variable nozzle vane mechanism 9 is connected to a motor rod 95c. The motor rod 95c is a rod-like member and is connected to a variable nozzle controller (not shown). The variable nozzle controller is connected to a direct current motor (DC motor) as an actuator. When the direct current motor rotates, the rotational force is transmitted to the motor rod 95c via a gear mechanism and a worm mechanism. As the drive link 95a rotates with the movement of the rod 95c, the nozzle vanes 96, 96,... Rotate as described above.

  As shown in FIGS. 5 and 6, when the motor rod 95c is pulled in the direction of the arrow X in the figure, the unison ring 92 rotates in the direction of the arrow X1 in the figure, and as shown in FIG. ,... Rotate in the counterclockwise direction in FIG.

  7 and 8 show a state in which the nozzle vane opening is set small, FIG. 7 is a front view of the variable nozzle vane mechanism 9 (a diagram corresponding to FIG. 5), and FIG. 8 is a back view of the variable nozzle vane mechanism 9. FIG. 7 is a diagram (corresponding to FIG. 6). As shown in these drawings, when the motor rod 95c is pushed in the direction of arrow Y in the figure, the unison ring 92 rotates in the direction of arrow Y1 in the figure, and as shown in FIG. 8, each nozzle vane 96, 96,. By rotating in the clockwise direction in the figure, the nozzle vane opening is set small.

  A pin 94a (see FIG. 5) is inserted into the nozzle plate 94, and a roller 94b is fitted into the pin 94a. The roller 94b guides the inner peripheral surface of the unison ring 92. Thereby, the unison ring 92 is held by the roller 94b and can rotate in a predetermined direction. A spacer bolt 51d is attached to the turbine housing 51c (see FIG. 4). Further, a cooling water passage W through which cooling water for cooling the turbocharger 5 flows is formed in the center housing 51b.

-Sensors-
Various sensors are attached to each part of the engine 1, and signals related to the environmental conditions of each part and the operating state of the engine 1 are output.

  For example, the air flow meter 43 outputs a detection signal corresponding to the flow rate of intake air (intake air amount) upstream of the throttle valve 62 in the intake system 6. The intake air temperature sensor 49 is disposed in the intake manifold 63 and outputs a detection signal corresponding to the temperature of the intake air. The intake pressure sensor 48 is disposed in the intake manifold 63 and outputs a detection signal corresponding to the intake air pressure. The A / F (air-fuel ratio) sensor 44 outputs a detection signal that continuously changes in accordance with the oxygen concentration in the exhaust gas downstream of the manipulator 77 of the exhaust system 7. Similarly, the exhaust temperature sensor 45 outputs a detection signal corresponding to the temperature of the exhaust gas (exhaust temperature) downstream of the manipulator 77 of the exhaust system 7. The rail pressure sensor 41 outputs a detection signal corresponding to the fuel pressure stored in the common rail 22. The throttle opening sensor 42 detects the opening of the throttle valve 62.

-ECU-
As shown in FIG. 9, the ECU 100 includes a CPU 101, a ROM 102, a RAM 103, a backup RAM 104, and the like. The ROM 102 stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU 101 executes various arithmetic processes based on various control programs and maps stored in the ROM 102. The RAM 103 is a memory that temporarily stores calculation results of the CPU 101, data input from each sensor, and the like. The backup RAM 104 is a nonvolatile memory that stores data to be saved when the engine 1 is stopped, for example. Memory.

  The CPU 101, the ROM 102, the RAM 103, and the backup RAM 104 are connected to each other via the bus 107, and are connected to the input interface 105 and the output interface 106.

  The input interface 105 is connected with the rail pressure sensor 41, the throttle opening sensor 42, the air flow meter 43, the A / F sensor 44, the exhaust temperature sensor 45, the intake pressure sensor 48, and the intake temperature sensor 49. Further, the input interface 105 includes a water temperature sensor 46 that outputs a detection signal corresponding to the cooling water temperature of the engine 1, an accelerator opening sensor 47 that outputs a detection signal corresponding to the depression amount of the accelerator pedal, and the engine 1. A crank position sensor 40 that outputs a detection signal (pulse) each time the output shaft (crankshaft) rotates by a certain angle is connected. On the other hand, the injector 23, the fuel addition valve 26, the throttle valve 62, the EGR valve 81, the variable nozzle vane mechanism 9 (the variable nozzle controller), and the like are connected to the output interface 106.

  The ECU 100 executes various controls of the engine 1 based on the outputs of the various sensors described above. Further, the ECU 100 controls pilot injection, pre-injection, main injection, after-injection, and post-injection described later as fuel injection control of the injector 23.

  The fuel injection pressure for executing these fuel injections is determined by the internal pressure of the common rail 22. As the common rail internal pressure, generally, the target value of the fuel pressure supplied from the common rail 22 to the injector 23, that is, the target rail pressure, increases as the engine load (engine load) increases and the engine speed (engine speed) increases. It will be expensive. That is, when the engine load is high, the amount of air sucked into the combustion chamber 3 is large. Therefore, a large amount of fuel must be injected from the injector 23 into the combustion chamber 3, and therefore the injection from the injector 23 is performed. The pressure needs to be high. Further, when the engine speed is high, the injection period is short, so the amount of fuel injected per unit time must be increased, and therefore the injection pressure from the injector 23 needs to be increased. . Thus, the target rail pressure is generally set based on the engine load and the engine speed.

  As for the fuel injection parameters in the fuel injection such as the pilot injection and the main injection, the optimum values vary depending on the temperature conditions of the engine 1 and the intake air.

  For example, the ECU 100 adjusts the fuel discharge amount of the supply pump 21 so that the common rail pressure becomes equal to the target rail pressure set based on the engine operating state, that is, the fuel injection pressure matches the target injection pressure. To measure. Further, the ECU 100 determines the fuel injection amount and the fuel injection form based on the engine operating state. Specifically, the ECU 100 calculates the engine rotation speed based on the detection value of the crank position sensor 40 and obtains the depression amount (accelerator opening) to the accelerator pedal based on the detection value of the accelerator opening sensor 47. The total fuel injection amount (the sum of the injection amount in the pre-injection and the injection amount in the main injection, which will be described later) is determined based on the engine speed and the accelerator opening.

-Fuel injection mode-
Hereinafter, an outline of each operation of the pilot injection, pre-injection, main injection, after-injection, and post-injection in the present embodiment will be described.

(Pilot injection)
Pilot injection is an injection operation in which a small amount of fuel is injected in advance prior to main injection (main injection) from the injector 23. That is, after the pilot injection is performed, the fuel injection is temporarily interrupted, and the compressed gas temperature (in-cylinder temperature) is sufficiently increased to reach the self-ignition temperature of the fuel until the main injection is started. This ensures good ignitability of the fuel injected in the main injection. That is, the pilot injection function in this embodiment is specialized for preheating in the cylinder. That is, the pilot injection in the present embodiment is an injection operation (preheating fuel supply operation) for preheating the gas in the combustion chamber 3.

Specifically, in the present embodiment, in order to optimize the distribution of the spray and the local concentration, the injection rate is set to the minimum injection rate (for example, the injection amount per injection 1.5 mm ³ ), and a plurality of pilots are performed. By executing the injection, the total pilot injection amount necessary for the pilot injection is ensured.

  In addition, the interval of the pilot injection that is divided and injected in this way is determined by the responsiveness of the injector 23 (speed of opening and closing operation). In the present embodiment, it is set to 200 μs, for example. The pilot injection interval is not limited to this value.

(Pre-injection)
The pre-injection is an injection operation (torque generating fuel supply operation) for suppressing the initial combustion speed by the main injection and leading to stable diffusion combustion, and is also called sub-injection. Specifically, in the present embodiment, the total injection amount (the injection amount in the pre-injection and the total injection amount for obtaining the required torque determined according to the operating state such as the engine speed, the accelerator operation amount, the coolant temperature, the intake air temperature, etc. The pre-injection amount is set to 10% with respect to the injection amount in the main injection).

In this case, when the total injection amount is less than 15 mm ³ , the injection amount in the pre-injection is less than the minimum limit injection amount (1.5 mm ³ ) of the injector 23, so the pre-injection is not executed. become. In this case, the fuel injection in the pre-injection may be performed by the minimum limit injection amount (1.5 mm ³ ) of the injector 23. On the other hand, when the total injection amount of the pre-injection is required to be at least twice the minimum limit injection amount of the injector 23 (for example, 3 mm ³ or more), it is necessary for this pre-injection by executing a plurality of pre-injections. The total injection amount is secured. Thereby, the ignition delay of the pre-injection can be suppressed, the initial combustion speed by the main injection can be surely suppressed, and the stable diffusion combustion can be led.

(Main injection)
The main injection is an injection operation (torque generation fuel supply operation) for generating torque of the engine 1. Specifically, in the present embodiment, the pre-injection from the total combustion injection amount for obtaining the required torque determined according to the operating state such as the engine speed, the accelerator operation amount, the cooling water temperature, the intake air temperature and the like. It is set as an injection amount obtained by subtracting the injection amount.

  The pre-injection and main injection control processes described above will be briefly described below. First, a total fuel injection amount that is the sum of the injection amount in the pre-injection and the injection amount in the main injection is calculated with respect to the torque request value of the engine 1. That is, the total fuel injection amount is calculated as an amount for generating the torque required for the engine 1.

  The torque request value of the engine 1 is determined according to the operating state of the engine speed, the amount of accelerator operation, the coolant temperature, the intake air temperature, and the like, and the usage status of the auxiliary machinery and the like. For example, the higher the engine speed (the engine speed calculated based on the detection value of the crank position sensor 40), the more the accelerator operation amount (the accelerator pedal depression amount detected by the accelerator opening sensor 47). The larger the value (the larger the accelerator opening), the higher the required torque value of the engine.

  After the total fuel injection amount is calculated in this way, the ratio (split rate) of the injection amount in the pre-injection with respect to the total fuel injection amount is set. That is, the pre-injection amount is set as an amount divided by the above-described division ratio with respect to the total fuel injection amount. This division ratio (pre-injection amount) is obtained as a value that achieves both “suppression of fuel ignition delay by main injection” and “suppression of the peak value of the heat generation rate of combustion by main injection”. By suppressing these, it is possible to reduce the combustion noise and the amount of NOx generated while securing a high engine torque. In the present embodiment, the division ratio is set to 10%.

(After spray)
After injection is an injection operation for increasing the exhaust gas temperature. Specifically, in this embodiment, after-injection is performed at a timing at which most of the combustion energy of the fuel supplied by this after-injection is obtained as exhaust heat energy without being converted into engine torque. I have to. Also in this after injection, as in the case of the pilot injection described above, this after injection is performed by performing a plurality of after injections with a minimum injection rate (for example, an injection amount of 1.5 mm ³ per injection). Therefore, the necessary total after injection amount is secured.

(Post injection)
The post-injection is an injection operation for directly introducing fuel into the exhaust system 7 to increase the temperature of the manipulator 77. For example, when the accumulated amount of PM trapped in the DPNR catalyst 76 exceeds a predetermined amount (for example, detected by detecting a differential pressure before and after the manipulator 77), post injection is performed. .

-Setting of target fuel pressure-
Next, a technical idea when setting the target fuel pressure in the present embodiment will be described.

  In the diesel engine 1, it is important to simultaneously satisfy various requirements such as improvement of exhaust emission by reducing the amount of NOx generated, reduction of combustion noise during the combustion stroke, and sufficient securing of engine torque. The inventor of the present invention can appropriately control the change state of the heat generation rate in the cylinder during the combustion stroke (change state represented by the heat generation rate waveform) as a method for simultaneously satisfying these requirements. Focusing on the effectiveness, we found a target fuel pressure setting method as described below as a method for controlling the change state of the heat generation rate.

  The solid line in FIG. 10 shows an ideal heat generation rate waveform related to combustion of fuel injected by main injection, with the horizontal axis representing the crank angle and the vertical axis representing the heat generation rate. TDC in the figure indicates the crank angle position corresponding to the compression top dead center of the piston 13. As this heat generation rate waveform, for example, combustion of fuel injected by main injection is started from the compression top dead center (TDC) of the piston 13, and a predetermined piston position after the compression top dead center (for example, compression top dead center). The heat generation rate reaches a maximum value (peak value) at 10 ° (at the time of ATDC 10 °), and a predetermined piston position after compression top dead center (for example, 25 ° after compression top dead center (ATDC 25 °)). The combustion of the fuel injected in the main injection ends at the time). If combustion of the air-fuel mixture is performed in such a state of change in heat generation rate, for example, 50% of the air-fuel mixture in the cylinder burns at 10 ° (ATDC 10 °) after compression top dead center. Completed status. That is, about 50% of the total heat generation amount in the expansion stroke is generated by ATDC 10 °, and the engine 1 can be operated with high thermal efficiency.

  In addition, the waveform shown with a dashed-dotted line in FIG. 10 has shown the heat release rate waveform which concerns on combustion of the fuel injected by the said pre-injection. Thereby, stable diffusion combustion of the fuel injected by the main injection is realized. For example, the amount of heat of 10 J is generated by the combustion of the fuel injected by this pre-injection. This value is not limited to this. For example, it is appropriately set according to the total fuel injection amount. Although not shown, pilot injection is also performed prior to pre-injection, thereby sufficiently increasing the in-cylinder temperature and ensuring good ignitability of fuel injected in main injection.

  Further, the waveform indicated by a two-dot chain line α in FIG. 10 is a heat generation rate waveform when the fuel injection pressure is set higher than an appropriate value, and both the combustion speed and the peak value are too high, and the combustion This is a state in which there is a concern about an increase in sound and an increase in the amount of NOx generated. On the other hand, the waveform indicated by the two-dot chain line β in FIG. 10 is a heat release rate waveform when the fuel injection pressure is set lower than the appropriate value, and the timing at which the combustion speed is low and the peak appears is greatly retarded. There is a concern that sufficient engine torque cannot be ensured by shifting to.

  As described above, the target fuel pressure setting method according to the present embodiment is a technical idea that the combustion efficiency is improved by optimizing the change state of the heat generation rate (optimization of the heat generation rate waveform). It is based on.

(Filling efficiency setting map)
As a feature of the present embodiment, a filling efficiency setting map referred to when determining the opening degree of the nozzle vanes 96, 96,... In the turbocharger 5 is stored in the ROM (storage means) 102.

  FIG. 11 shows this filling efficiency setting map. In this charging efficiency setting map, the horizontal axis represents the engine speed, and the vertical axis represents the engine torque. That is, the map is used to obtain the opening degree of the nozzle vanes 96, 96,... Suitable for the current engine operating state according to the engine speed and the engine torque. Further, Tmax in FIG. 11 indicates a maximum torque line. Further, the hatched area in FIG. 11 is an EGR area where the EGR valve 81 is opened and a part of the exhaust gas is recirculated to the intake system 6, and the other areas are non-EGR where the EGR valve 81 is closed. (No EGR) area.

  This filling efficiency setting map indicates that the nozzle vanes 96, 96,... Have the maximum intake supercharging efficiency (the highest point of the intake supercharging efficiency) according to the operating state of the engine 1 (engine speed, engine torque). The degree of opening is acquired. In other words, in the charging efficiency setting map, the nozzle vanes 96, 96,..., The opening suitable values (control values of the charging efficiency variable means) that maximize the intake supercharging efficiency are stored for each operating state. .

  Here, the highest point of the intake supercharging efficiency means that the opening degree of the nozzle vanes 96, 96,... Is adjusted when the fuel injection amount into the cylinder, the fuel injection pattern, and the fuel injection pressure are substantially constant. When the engine torque changes accordingly, the engine torque reaches its maximum value. That is, the opening at which the opening degree of the nozzle vanes 96, 96,... At the time when the engine torque reaches the maximum value is the maximum supercharging efficiency in the operating state (engine speed, engine torque) of the engine 1 at that time. The value of the opening is written in the charging efficiency setting map as an appropriate value in the engine operating state. This will be specifically described below.

  FIG. 12 shows the amount of fuel injected into the cylinder, fuel injection pattern (pre-injection and main injection timings, intervals, etc.) in a certain engine operating state (the throttle valve 62 is fully opened in the non-EGR region). This shows a change in engine torque when the opening degree of the nozzle vanes 96, 96,... Is changed in a state where the fuel injection pressure is substantially constant. The horizontal axis in FIG. 12 is the filling efficiency determined by the opening degree of the nozzle vanes 96, 96,..., And the filling efficiency increases as the opening degree of the nozzle vanes 96, 96,. Moreover, the vertical axis | shaft in FIG. 12 is an engine torque.

  Here, as a specific example of the case where the fuel injection amount into the cylinder, the fuel injection pattern, and the fuel injection pressure are substantially constant, the fuel injection amount and the fuel injection pattern are, for example, those of the fuel injected by the pre-injection. The timing at which the heat generation rate due to combustion is maximized, the timing at which combustion of fuel injected by main injection is started, and the timing at which the piston 13 reciprocating in the cylinder reaches compression top dead center substantially coincide with each other. There is a case where the injection timing and the injection amount of the pre-injection and the main injection are fixed. As for the fuel injection pressure, an equal fuel injection pressure region is assigned to an equal output region (equal power line) of output (power) obtained from the engine speed and engine torque, and the fuel injection pressure is determined according to the output of the engine 1. In this case, the fuel injection pressure is set to a fixed value.

  As shown in FIG. 12, when the opening degree of the nozzle vanes 96, 96,... Is large (the throat area is large: the filling efficiency is low), the opening degree is gradually reduced (the filling efficiency is gradually increased). As a result, the amount of exhaust gas converted from heat energy to rotational energy in the turbocharger 5 gradually increases, and the engine torque increases accordingly (see the charging efficiency range I in FIG. 12). However, when the opening degree of the nozzle vanes 96, 96,... Is reduced in this way, the exhaust energy increases, that is, exhaust gas exhaustion worsens. It gets bigger. And the balance between the amount of increase in rotational energy (energy amount contributing to efficiency improvement) by reducing the opening degree of the nozzle vanes 96, 96,... And the amount of increase in exhaust energy (energy amount leading to deterioration in efficiency). As the increase amount of the exhaust energy increases, the supercharging efficiency decreases (see the charging efficiency range II in FIG. 12). Therefore, a point (a boundary point between the charging efficiency ranges I and II) where the increased amount of rotational energy and the increased amount of exhaust energy are balanced is obtained as the maximum point of supercharging efficiency.

  The opening (adapted value) of the nozzle vanes 96, 96,..., Which is the maximum point of the supercharging efficiency obtained in this way, is determined for each operating state of the engine and obtained on the coordinates (horizontal axis). 11 is plotted on the coordinates with the engine speed as the vertical axis and the engine torque as the vertical axis), and the filling efficiency setting map shown in FIG. 11 is obtained by connecting the nozzle vanes 96, 96,. In this filling efficiency setting map, lines indicated by A to I (each line indicated by a broken line) are a set of points where the opening degree of the nozzle vanes 96, 96,... Is the same (a set of points having the same filling efficiency). This is an equal filling efficiency line (equal filling efficiency region). That is, on this equal charging efficiency line, the opening degree of the nozzle vanes 96, 96,... For obtaining the maximum point of supercharging efficiency is the same.

  In other words, this equal charging efficiency line is a set of points at which the supercharging efficiency of the turbocharger 5 is maximized, and the nozzle vane 96 corresponding to the equal charging efficiency line selected based on the rotational speed and torque of the engine 1. , 96,... Can be set to maximize the supercharging efficiency of the turbocharger 5.

  Specifically, a curve A in FIG. 11 is a line having a nozzle vane opening degree of 90%, the nozzle vane opening degree is set to be smaller by 10% from the curve B toward the curve I, and the curve I has a nozzle vane opening degree of 10%. It has become a line. These values are not limited to this, and are set as appropriate according to the performance characteristics of the engine 1 and the like.

  In accordance with the charging efficiency setting map created in this way, the opening control of the nozzle vanes 96, 96,... During the operation of the engine 1 according to the present embodiment uses the charging efficiency of intake air suitable for the operating state of the engine 1. The variable nozzle vane mechanism 9 is controlled so as to set the opening degree of the nozzle vanes 96, 96,... So as to obtain the filling efficiency from the filling efficiency setting map (the filling efficiency by the filling efficiency control means). Control action of variable means).

  In this way, by setting the opening degree of the nozzle vanes 96, 96,..., The intake supercharging efficiency can be maximized in any engine operating state, and the engine 1 can be operated with high efficiency. This can greatly improve the fuel consumption rate.

  Further, as described above, in the filling efficiency setting map in the present embodiment, a unique correlation is provided among the engine speed, the engine torque, and the nozzle vane opening (filling efficiency). This makes it possible to maintain a high supercharging efficiency over the entire engine operating region. Also, as shown in this charging efficiency setting map, having a unique correlation among the engine speed, engine torque, and nozzle vane opening is a systematic intake control method common to various engines. Since it is constructed, it is possible to simplify the creation of a charging efficiency setting map for setting an appropriate intake amount according to the operating state of the engine 1.

(Automatic filling efficiency adapting device)
Next, a filling efficiency automatic adaptation device (automatic adaptation tool) used for obtaining the adaptation value of the opening degree of the nozzle vane 96 as described above will be described. That is, the above-described filling efficiency setting map is created based on the matching value for each engine operating state acquired by this filling efficiency automatic adaptation device.

  In general, in the control of an automobile engine, various control parameters such as fuel injection timing are determined in accordance with an engine operating state such as an engine speed and an engine load. Each control parameter in each operating state is preliminarily adapted so that various engine characteristics such as exhaust emission characteristics and fuel consumption characteristics satisfy the requirements.

  Conventionally, such adaptation of control parameters is performed by repeated trial and error on an engine bench. That is, the output shaft of the in-vehicle engine and the dynamometer are connected by a rotational drive shaft, and the load torque of the in-vehicle engine is absorbed as a test torque by the dynamometer, so that the in-vehicle engine is mounted and operated in the vehicle. Simulate. Then, various engine characteristic values such as nitrogen oxide emission amount and fuel consumption amount are measured while adjusting the control parameter in each operation state, and the optimum value of the control parameter is acquired as a suitable value. In order to adapt such control parameters, trial and error and a great deal of time are required.

  Such a situation is the same when determining the charging efficiency of intake air. That is, when determining the opening degree of the nozzle vanes 96, 96,..., Conventionally, trial and error and enormous amount of time are required. The automatic filling efficiency adapting apparatus in the present embodiment automatically determines the filling efficiency. This will be specifically described below.

  FIG. 13 shows a system configuration for automatically adjusting the filling efficiency. As shown in FIG. 13, the dynamometer 110 generates a state in which the engine 1 is mounted on the vehicle in a pseudo manner by absorbing the output torque of the engine 1. The measuring device 120 is a device that measures the exhaust characteristics of the engine 1 or the like and measures the rotational speed of the crankshaft of the engine 1. Further, the automatic adaptation device 130 constituted by an adaptation computer operates the dynamometer 110 and sets the operation amounts of various actuators such as the supply pump 21, the injector 23, and the variable nozzle vane mechanism 9 as appropriate. Therefore, each actuator is operated via the ECU 100. And in the automatic adaptation apparatus 130, based on the measurement result by the measurement apparatus 120, each adaptation including the said filling efficiency is performed.

  And the operation | movement for performing the automatic adaptation of the said filling efficiency is performed as follows. FIG. 14 is a flowchart showing a procedure for performing the automatic adaptation of the filling efficiency. The routine shown in FIG. 14 is executed for each engine operating state, and an appropriate value for each engine operating state is acquired to contribute to the creation of the above-described filling efficiency setting map.

  At the start of the automatic adjustment operation of the charging efficiency, the opening degree of the nozzle vanes 96, 96,... Is maximum, that is, the charging efficiency is minimized.

  When the automatic adjustment operation of the charging efficiency is started, first, in step ST1, the engine torque (TRQi) in the engine operating state as a measurement target is measured. Thereafter, the process proceeds to step ST2, and it is determined whether or not the engine torque measured in step ST1 is the maximum value. Since engine torque information in the current engine operating state does not exist at the start of the automatic adaptation operation, it is determined here that the engine torque is the maximum value (Yes is determined in step ST2), and the process proceeds to step ST3. Move. In step ST3, the engine torque is read as torque at the maximum efficiency (TRQmax: hereinafter referred to as maximum torque).

  Then, it moves to step ST4 and determines whether the engine torque has increased. Since the past engine torque information does not exist at the start of the automatic adaptation operation, a No determination is made here, and the process proceeds to step ST5.

  In step ST5, the opening degree of the nozzle vanes 96, 96,... Is set small by a predetermined amount (for example, 5% of the rotatable range), that is, the filling efficiency is slightly increased, and then the process proceeds to step ST1 again.

  In this step ST1, the engine torque (TRQi) is measured in the same manner as described above. Thereafter, the process proceeds to step ST2, and it is determined whether or not the engine torque measured in step ST1 is the maximum value. That is, is the engine torque (TRQi) measured this time larger than the engine torque (engine torque registered as TRQmax) measured in the previous engine torque measurement operation (step ST1 in the previous routine)? Whether or not (TRQi> TRQmax is satisfied) is determined.

  Here, the engine torque measured this time is larger than the engine torque measured in the previous engine torque measurement operation (TRQi> TRQmax), and if a Yes determination is made in step ST2, the process proceeds to step ST3. The newly measured engine torque (TRQi) is updated as the maximum torque (TRQmax), and the process proceeds to step ST4. On the other hand, when the engine torque measured this time is smaller than the engine torque measured in the previous engine torque measurement operation (TRQ <TRQmax) and No is determined in step ST2, the maximum torque (TRQmax) is determined. Without moving to step ST4.

  In step ST4, the engine torque (TRQi) is compared with the torque (TRQmax-B) obtained by subtracting a predetermined amount from the maximum torque (TRQmax), and whether or not the former (TRQi) is smaller than the latter (TRQmax-B). Determine. The predetermined value “B” here is hysteresis for absorbing torque measurement variation. In addition, when the determination area is an EGR area, it is a supercharging area expansion determination value for EGR rate contour plotting.

  If the determination in step ST4 is No, the process proceeds to step ST5 again, and the above-described operation is automatically repeated. That is, the above-described acquisition of the engine torque (TRQi) and the update of the maximum torque (TRQmax) are obtained until the opening degree (filling efficiency) of the nozzle vanes 96, 96,. Repeat automatically.

  On the other hand, if the determination in step ST4 is Yes, the updated maximum torque (TRQmax) is the opening (filling efficiency) of the nozzle vanes 96, 96,... That generates the maximum torque in the current engine operating state. Then, the process proceeds to step ST6, and the opening degree of the nozzle vanes 96, 96,. Thereby, a suitable value is acquired for one engine operating state.

  The operation as described above is automatically executed for each engine operating state, and the adaptive value for each operating state is obtained. These adaptive values are expressed on the coordinates (the horizontal axis is the engine speed, and the vertical axis is the engine torque. .. Is plotted, and the filling efficiency setting map shown in FIG. 11 is created by connecting points having the same opening degree of the nozzle vanes 96, 96,.

  The above is the automatic adaptation operation of the filling efficiency for creating the filling efficiency setting map.

  As described above, in this embodiment, the charging efficiency (the opening degree of the nozzle vanes 96, 96,...) That maximizes the supercharging efficiency can be automatically adapted, and a suitable value can be obtained by trial and error. This eliminates the need for an enormous amount of time for acquisition, and improves the efficiency of the adaptation operation.

  In the above-described automatic adaptation operation of the charging efficiency, the engine torque (TRQi) is measured while changing the opening degree of the nozzle vanes 96, 96,. Instead, any of the following values may be measured or calculated while changing the opening of the nozzle vanes 96, 96,... To automatically adapt the filling efficiency.

・ TRQi / QFUELi
・ TRQi / TRQmax
・ (TRQi / QFULi) / (TRQmax / QFUELmax)
・ Net fuel consumption (BSFC (g / kWh): Brake Specific Fuel Consumption)
Here, TRQi is the torque at each measurement point, QFUELi is the consumed fuel flow rate at the time of TRQi measurement, TRQmax is the torque at the maximum efficiency, and QFUELmax is the consumed fuel flow rate at the time of TRQmax measurement. As a precondition for making these physical quantities effective, it is necessary to have a one-to-one correspondence with the differential pressure across the turbine wheel 52c.

-Other embodiments-
In the embodiment described above, the case where the present invention is applied to an in-line four-cylinder diesel engine mounted on an automobile has been described. The present invention is applicable not only to automobiles but also to engines used for other purposes. Further, the number of cylinders and the engine type (separate type engine, V-type engine, etc.) are not particularly limited. The present invention can also be applied to a gasoline engine.

  In the above-described embodiment, the NSR catalyst 75 and the DPNR catalyst 76 are provided as the manipulator 77. However, the manifold 77 may be provided with an NSR catalyst 75 and a DPF (Diesel Particle Filter).

  In the above-described embodiment, the charging efficiency setting map is created using the matching value acquired by the charging efficiency automatic adaptation device 130, and the charging efficiency of intake air suitable for the current engine operating state is created from the charging efficiency setting map. Are read out and the opening degree of the nozzle vanes 96, 96,... Is set. The present invention is not limited to this, and a filling efficiency setting map is created by obtaining an appropriate value for each engine operating state through experiments and simulations, and the opening degree of the nozzle vanes 96, 96,. May be set.

  Furthermore, the automatic adjustment device 130 according to the present invention is not limited to being used as an automatic adjustment tool for acquiring an adjustment value of filling efficiency, but can also be used as a simulation prediction tool for simulating the operating state of the engine. It is.

It is a schematic block diagram of the engine which concerns on embodiment, and its control system. It is sectional drawing which shows the combustion chamber of a diesel engine, and its peripheral part. It is sectional drawing along the axial center of the turbine shaft in a turbocharger. It is sectional drawing which expands and shows the turbine wheel of a turbocharger, and its peripheral part. It is a front view of the variable nozzle vane mechanism in the state where the nozzle vane opening degree was set large. It is a rear view of the variable nozzle vane mechanism in a state where the nozzle vane opening degree is set to be large. It is a front view of the variable nozzle vane mechanism in the state where the nozzle vane opening degree was set small. It is a rear view of the variable nozzle vane mechanism in the state where the nozzle vane opening degree was set small. It is a block diagram which shows the structure of control systems, such as ECU. It is a wave form diagram which shows the change state of the heat release rate at the time of an expansion stroke. It is a figure which shows a filling efficiency setting map. It is a figure which shows the relationship between the charging efficiency in a certain engine operating state, and an engine torque. It is a figure which shows the system configuration | structure for performing automatic adaptation of filling efficiency. It is a flowchart figure which shows the procedure for performing automatic adaptation of filling efficiency.

Explanation of symbols

1 engine (internal combustion engine)
3 Combustion chamber 23 Injector (fuel injection valve)
5 Turbocharger (supercharger)
52c Turbine wheel 9 Variable nozzle vane mechanism (Filling efficiency variable means)
96 nozzle vane 102 ROM (storage means)
130 Automatic adaptation device

Claims (4)

In an intake air control apparatus for an internal combustion engine provided with charging efficiency variable means for changing the charging efficiency of intake air supplied toward the cylinder of the internal combustion engine,
By changing the charging efficiency of intake air set by the charging efficiency variable means in a state where the fuel injection amount, fuel injection pattern, and fuel injection pressure into the cylinder are substantially constant, a plurality of the internal combustion engines Storage means for storing the control value of the charging efficiency variable means, which is obtained in advance for each of the operating states, and the intake supercharging efficiency is substantially maximum;
And a charging efficiency control means for reading a control value corresponding to the operating state from the storage means during operation of the internal combustion engine and controlling the charging efficiency variable means using the control value as a target value. An intake control device for an internal combustion engine. In the intake control device for an internal combustion engine according to claim 1,
The charging efficiency variable means is provided in the supercharger and changes the flow area of the gas flowing toward the turbine wheel by changing the opening degree of the nozzle vane that can be opened and closed by the variable nozzle vane mechanism. It is configured to change the charging efficiency of intake air by changing the supercharging pressure,
The charging efficiency control means is configured to control the variable nozzle vane mechanism so as to set the opening degree of the nozzle vane with the control value corresponding to the operation state as a target value when the internal combustion engine is in operation. An intake control device for an internal combustion engine. For an internal combustion engine provided with a charging efficiency variable means for varying the charging efficiency of intake air supplied toward the cylinder, the intake supercharging efficiency is set as a control value of the charging efficiency variable means for each operating state of the internal combustion engine. Is an automatic adapting device for obtaining a conforming value that is approximately the maximum,
For each of a plurality of operating states of the internal combustion engine, the charging efficiency of the intake air set by the charging efficiency variable means is changed with the fuel injection amount into the cylinder, the fuel injection pattern, and the fuel injection pressure being substantially constant. The internal combustion engine is configured to automatically acquire the control value of the charging efficiency variable means at the time when the intake supercharging efficiency becomes substantially maximum as a conforming value in its operating state Automatic fitting device. In an intake air control apparatus for an internal combustion engine provided with charging efficiency variable means for changing the charging efficiency of intake air supplied toward the cylinder of the internal combustion engine,
For each of a plurality of operating states of the internal combustion engine, the charging efficiency of the intake air set by the charging efficiency variable means is changed with the fuel injection amount into the cylinder, the fuel injection pattern, and the fuel injection pressure being substantially constant. The control values of the charging efficiency variable means at the time when the intake air supercharging efficiency becomes substantially maximum are stored as the adaptive values in the operating state, and the respective adaptive values obtained by the automatic adaptive device are stored. Storage means for
And a charging efficiency control means for reading an appropriate value corresponding to the operating state from the storage means during operation of the internal combustion engine and controlling the charging efficiency variable means using the appropriate value as a target value. An intake control device for an internal combustion engine.

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