JP5720479B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine represented by a diesel engine. In particular, the present invention relates to control in which a control parameter of an internal combustion engine is variable in accordance with a driver's driving characteristics (for example, individual differences in accelerator pedal depression speed, etc.).

  As is well known in the art, in a diesel engine used as an automobile engine or the like, in order to improve exhaust emission, secure high engine torque, improve fuel consumption rate, etc., the engine speed, accelerator operation amount, Control parameters of various control devices are adjusted according to the cooling water temperature, the intake air temperature, and the like. For example, the fuel injection amount and fuel injection timing from a fuel injection valve (hereinafter also referred to as “injector”) are adjusted. Further, the exhaust gas recirculation rate (EGR rate) is adjusted by controlling the opening of an EGR valve provided in an EGR (Exhaust Gas Recirculation) device that recirculates exhaust gas to the intake system for the purpose of reducing NOx emissions. The

  Further, there are Patent Document 1 and Patent Document 2 described below that adjust control parameters according to the transient operation of the engine.

  In Patent Document 1, the operating state of the engine is determined from the time change rate of the accelerator opening, and when the engine is outside the steady operation range (during engine transient operation), the EGR gas recirculation is stopped (EGR cut). While improving drivability, a large amount of EGR gas is recirculated to the intake system when the engine is in a steady operation region to improve exhaust emission.

  Further, in Patent Document 2, a bypass valve is provided in a bypass passage that bypasses a supercharger (supercharger) provided in an intake system, and the bypass valve is opened during a transient operation of the engine during sudden deceleration. An increase in the temperature of the supercharger is suppressed by reverse intake air flow caused by accelerating (by returning a part of the air discharged from the supercharger to the upstream of the supercharger by causing the bypass passage to flow backward).

  By the way, in general, a driver who drives a vehicle has individual differences in driving characteristics. For example, there is an individual difference in the depression speed of the accelerator pedal (amount of change in the opening direction per unit time of the accelerator pedal) when the vehicle is requested to accelerate, for example, when shifting from steady operation to transient operation. That is, even when the same acceleration is requested, there are drivers with a relatively low accelerator pedal depression speed and drivers with a relatively high depression speed.

  As an engine control system, a so-called robust system should be constructed so that no matter what kind of driver drives the vehicle, it does not cause problems such as misfire in the cylinder. is necessary. In other words, for a driver with a relatively high accelerator pedal depressing speed, the engine operating point with a large accelerator opening (the required output) from the engine operating point with a small accelerator opening (the operating point with a small required output). It is necessary to adjust various control amounts so that there is no trouble in driving even if a control delay occurs at the time of transition to a large operating point).

  For example, in steady operation with a relatively small accelerator opening, the recirculation amount of the EGR gas is relatively large (the oxygen concentration in the cylinder is relatively small), and the fuel injection amount from the injector is relatively small. The injection timing is set to a relatively advanced angle side (since the oxygen concentration in the cylinder is relatively small, the injection timing is set to the advanced angle side to prevent combustion delay). From this state, when the accelerator pedal is depressed at a high depression speed and transition is made to a transient operation, the opening of the EGR valve is reduced rapidly to reduce the recirculation amount of the EGR gas. Increase the oxygen concentration, rapidly set the fuel injection amount from the injector, rapidly shift the injection timing to the retarded side, and change the accelerator opening (with a relatively large accelerator opening) It is necessary to perform control to shift to the operating point early. However, when there is a delay in changing the opening of the EGR valve, the fuel injection amount from the injector increases while the oxygen concentration in the cylinder remains low, and the injection timing changes to the retard side. It will be. As a result, in the combustion field in the cylinder, the actual oxygen amount is less than the appropriate oxygen amount for the increased fuel injection amount, and the oxygen concentration (the oxygen concentration that is lowered due to the control delay) is reduced. The actual fuel injection timing is set to the retarded side rather than the suitable fuel injection timing, and due to these, there is a concern that the combustion in the cylinder may deteriorate and lead to misfire.

  Considering the possibility that such a situation may occur, an actual engine control system may, for example, set an exhaust gas recirculation amount during steady operation to be small in advance and Insufficient oxygen concentration is avoided, and even if there is a delay in changing the opening of the EGR valve, a sufficient oxygen concentration is secured to prevent misfire.

JP-A-7-158514 JP-A-6-193457

  When the control amount (exhaust recirculation amount in the above case) is adjusted so that misfire does not occur even if a control delay occurs in this way, a driver with a relatively high accelerator pedal depression speed is driving It is effective in preventing the occurrence of misfire. However, when a driver whose driving speed of the accelerator pedal is relatively low is driving, the oxygen concentration in the cylinder is set higher than necessary. In other words, even if the oxygen concentration in the cylinder is set to a lower value, there will be no misfire in transient operation (transitional operation where the accelerator pedal is depressed at a relatively low speed). Although the oxygen concentration is set lower, the exhaust emission can be improved (reduction of NOx generation) and the fuel consumption rate can be improved. The actual situation is that the oxygen concentration is set to be high in advance in consideration of the possibility that a driver having a relatively high accelerator pedal depression speed may drive.

  In view of this point, the inventor of the present invention learns the driving characteristics of the driver, and controls the various driving characteristics of the driver by changing the engine control parameters in accordance with the learned driving characteristics. The inventors have found that the parameters can be optimized and have arrived at the present invention.

  The present invention has been made in view of such points, and an object of the present invention is to provide a control device for an internal combustion engine that can optimize the control parameters of the internal combustion engine in accordance with the driving characteristics of the driver. There is to do.

-Summary of invention-
The outline of the present invention taken in order to achieve the above object is to obtain the driving transient degree of the driver by comparing the in-cylinder state during the steady operation of the internal combustion engine with the actual in-cylinder state. The control parameters of the internal combustion engine are corrected according to the determined operating transient. In other words, when the driver's driving transient is high, the control parameters are corrected with priority given to the robustness of the internal combustion engine, while when the driver's driving transient is low, the exhaust emission and fuel consumption of the internal combustion engine are corrected. The control parameters are corrected so as to give priority to the improvement of the rate.

-Solution-
Specifically, the present invention presupposes a control apparatus for an internal combustion engine that adjusts control parameters according to the degree of transient operation during transient operation of the internal combustion engine. Information on the value of the in-cylinder state quantity when the steady state operation is performed with the control parameters of the internal combustion engine adapted so that the exhaust emission and the fuel consumption rate both satisfy the required values. The in-cylinder state in the above-mentioned adapted steady operation from a certain in-cylinder state quantity reference value (Xb) and the actual in-cylinder state quantity (Xr) that is information of the in-cylinder state quantity in the actual operating state of the internal combustion engine A state quantity deviation (ΔX) that is a deviation of the in-cylinder state quantity in the actual operating state of the internal combustion engine with respect to the quantity is calculated, and the current state is calculated with respect to the average value of the state quantity deviation (ΔX) calculated in the past The state quantity deviation average value (ΔXave) is calculated by reflecting the quantity deviation (ΔX) by the smoothing calculation, and the state quantity deviation (ΔX) in the test mode when the vehicle is driven in the predetermined test mode. Is obtained in the same manner as the operation for calculating the state quantity deviation (ΔX), is set as the state quantity change maximum reference value (ΔXb-ave), and the state with respect to the state quantity change maximum reference value (ΔXb-ave) is determined. The driver's driving transient degree is learned by the ratio of the quantity deviation average value (ΔXave) or the deviation between the state quantity change maximum reference value (ΔXb-ave) and the state quantity deviation average value (ΔXave) . The control parameter is adjusted in accordance with the learned driving transient level of the driver.

Due to this specific matter, when the operation state of the internal combustion engine is transient and the operation transient degree is relatively low, the control delay is small, so the state quantity change maximum reference value (ΔXb-ave) And the state quantity deviation average value (ΔXave) are small, and it is recognized that the driving transient degree of the driver is low. For example, there is a case where the accelerator pedal is depressed at a low speed. In this case, the actual in-cylinder state quantity can be brought closer to the target value of the in-cylinder state quantity at an early stage, and the internal combustion engine is less susceptible to deterioration of the combustion state such as misfire. As a control parameter, it is possible to perform correction on the side giving priority to exhaust emission and improvement of the fuel consumption rate.

On the other hand, when the operation state of the internal combustion engine is transient and the operation transient degree is relatively high, the control delay is large, so the state quantity change maximum reference value (ΔXb-ave) and the state quantity deviation average The difference from the value (ΔXave) is large, and it is recognized that the driver's driving transient is high. For example, there is a case where the accelerator pedal is depressed at a high speed. In this case, since the actual in-cylinder state quantity is greatly deviated from the target value of the in-cylinder state quantity, as a control parameter of the internal combustion engine, the deterioration of the combustion state such as misfire does not occur. Correction is performed with priority given to robustness.

In this way, the control parameters are adjusted according to the driving transient of the driver, so that the control parameters can be optimized, and even if the driving transient of the driver is high, no misfire is caused. In addition, when the driver's driving transient is low, it is possible to improve exhaust emission and improve the fuel consumption rate.
In general, a specified vehicle running test mode (for example, EC mode in Europe, JC08 mode in Japan, etc.) is tested with a running pattern when an average user (a general driver) drives the vehicle. It has become a thing. That is, it simulates average transient operation. For this reason, the state quantity change maximum reference value (ΔXb) is obtained by comparing the change in the in-cylinder state quantity during the actual vehicle travel with the change in the in-cylinder state quantity when the vehicle is driven in this test mode. -ave) can be obtained as a difference of the state quantity deviation average value (ΔXave), so that the actual running state (actual driving transient) with respect to the general running state (average driving transient) Therefore, it is possible to establish the criteria for determining the operation transient.

Specific configurations in the case where the control parameter is the in-cylinder oxygen concentration include the following. That is, the in-cylinder oxygen concentration as a control parameter is corrected according to the learned driving transient level of the driver.

In this case, when the ratio of the state quantity deviation average value (ΔXave) to the state quantity change maximum reference value (ΔXb-ave) is less than “1”, or from the state quantity deviation average value (ΔXave) , the state When the value obtained by subtracting the maximum amount change reference value (ΔXb-ave) is less than “0”, the smaller the value, the lower the in-cylinder oxygen concentration as the control parameter is corrected.

  According to this, as the driver's driving transient is lower, the in-cylinder oxygen concentration is set lower, and the correction amount in the direction in which the exhaust emission can be improved (particularly, the reduction of NOx emissions) becomes larger. become. Thereby, the optimal adjustment of the in-cylinder oxygen concentration according to the driving transient degree of the driver can be realized.

On the other hand, when the ratio of the state quantity deviation average value (ΔXave) to the state quantity change maximum reference value (ΔXb-ave) is “1” or more, or from the state quantity deviation average value (ΔXave) , the state quantity When the value obtained by subtracting the maximum change reference value (ΔXb-ave) is equal to or greater than “0”, the in-cylinder oxygen concentration as the control parameter is constant so that the exhaust emission satisfies the regulation value even if the value increases. Keep the value of.

  This is because if the in-cylinder oxygen concentration is increased as the driving transient is high, the fuel consumption rate is improved, but the NOx emission exceeds the regulation value. This is to avoid this. That is, when the driver's driving transient is high, the fuel consumption rate can be improved as much as possible while keeping the NOx emission amount below the regulation value.

Specific configurations when the control parameter is the fuel ignition timing include the following. That is, the fuel ignition timing as a control parameter is corrected according to the learned driving transient level of the driver.

In this case, when the ratio of the state quantity deviation average value (ΔXave) to the state quantity change maximum reference value (ΔXb-ave) is less than “1”, or from the state quantity deviation average value (ΔXave) , the state When the value obtained by subtracting the maximum reference value (ΔXb-ave) of the amount change is less than “0”, the smaller the value is, the more the fuel ignition timing as the control parameter is corrected to the advance side.

  According to this, as the driver's driving transient is lower, the fuel ignition timing is set to the advance side, and the correction amount in the direction in which the fuel consumption rate can be improved increases. Thereby, adjustment of the optimal fuel ignition timing according to the driving | running | working transient degree of a driver | operator is realizable.

On the other hand, when the ratio of the state quantity deviation average value (ΔXave) to the state quantity change maximum reference value (ΔXb-ave) is “1” or more, or from the state quantity deviation average value (ΔXave) , the state quantity When the value obtained by subtracting the maximum change reference value (ΔXb-ave) is equal to or greater than “0”, the fuel ignition timing as a control parameter is set to a constant value that satisfies the regulation value even when the value increases. Value or a constant value that satisfies the required output.

  This is because if the driver's driving transient is high, the higher the driving transient, the more the fuel ignition timing shifts to the retarded side, which leads to deterioration of combustion due to the ignition delay and deterioration of exhaust emission. In order to avoid this, there is a possibility of inviting or failing to obtain the required output.

  The in-cylinder state quantity is at least one of in-cylinder pressure, in-cylinder temperature, and in-cylinder oxygen concentration.

When the operating state of the internal combustion engine is transient, the amount of in-cylinder state during steady operation (at least one of in-cylinder pressure, in-cylinder temperature, and in-cylinder oxygen concentration) by the amount of control delay The actual in-cylinder state amount will deviate (for example, if there is a delay in the opening control of the EGR valve, the in-cylinder oxygen concentration will deviate). By detecting this deviation amount, Whether the current operation state of the internal combustion engine is a steady operation or a transient operation, and if it is a transient operation, the degree of the transient operation (operation transient degree) can be determined. That is, the state quantity deviation average value (ΔXave) can be calculated by comparing the in-cylinder state quantity, and the driving transient can be calculated with higher accuracy than when only the absolute amount such as the detected value of the accelerator opening is recognized. It becomes possible to recognize the degree of transient.

In the present invention, the driver is compared by comparing the state quantity deviation average value obtained based on the in-cylinder state quantity in the operating state of the internal combustion engine and the state quantity change maximum reference value defined as the reference value of the in-cylinder state quantity. And the control parameter is adjusted according to the recognized driver's driving transient. For this reason, the control parameters can be optimized, no misfire is caused, and the exhaust emission and the fuel consumption rate can be improved.

It is a figure which shows schematic structure 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 a block diagram which shows the structure of control systems, such as ECU. It is a schematic diagram of the intake / exhaust system and the combustion chamber for explaining the outline of the combustion mode in the combustion chamber. It is sectional drawing which shows a combustion chamber at the time of fuel injection and its peripheral part. It is a top view of the combustion chamber at the time of fuel injection. It is a flowchart figure which shows the procedure of driving | running | working transient degree determination operation | movement. FIG. 8A is a timing chart showing a change in accelerator opening, a change in target oxygen concentration, and a change in actual oxygen concentration during transient operation, and FIG. 8A shows a case where the change speed of the accelerator opening is relatively low. 8 (b) is a diagram showing a case where the change rate of the accelerator opening is relatively high. It is a flowchart figure which shows the procedure of the cylinder oxygen concentration correction | amendment operation | movement in 1st Embodiment. FIG. 6 is a diagram showing an oxygen concentration target correction value map that is employed when the driver transient degree Rt is obtained as the ratio of the state quantity deviation average value ΔXave to the state quantity change maximum reference value ΔXb-ave in the first embodiment. FIG. 6 is a diagram illustrating an oxygen concentration target correction value map that is employed when the driver transient degree Rt is obtained as the difference between the state quantity change maximum reference value ΔXb-ave and the state quantity deviation average value ΔXave in the first embodiment. . It is a flowchart figure which shows the procedure of the control parameter correction | amendment operation | movement in 2nd Embodiment. In a 2nd embodiment, it is a figure showing ignition timing target amendment value map adopted when driver transient Rt is calculated as a ratio of state quantity deviation average value deltaXave with state quantity change maximum reference value deltaXb-ave. FIG. 10 is a diagram showing an ignition timing target correction value map that is employed when the driver transient degree Rt is obtained as the difference between the state quantity change maximum reference value ΔXb-ave and the state quantity deviation average value ΔXave in the second embodiment. . It is a figure for demonstrating the change of NOx discharge | emission amount and fuel consumption rate in 2nd Embodiment.

  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. Moreover, FIG. 2 is sectional drawing which shows the combustion chamber 3 of a diesel engine, and its peripheral part.

  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.

  Further, 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 at which the exhaust A / F becomes the target A / F) by the addition control operation by the ECU 100. The 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 (intake 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.

  Further, the intake system 6 is provided with a swirl control valve (swirl speed variable mechanism) 66 for making the swirl flow (horizontal swirl flow) in the combustion chamber 3 variable (see FIG. 2). . Specifically, as the intake port 15a, two systems, a normal port and a swirl port, are provided for each cylinder. Of these, a normal valve 15a shown in FIG. A swirl control valve 66 is disposed. An actuator (not shown) is connected to the swirl control valve 66, and the flow rate of air passing through the normal port 15a can be changed according to the opening of the swirl control valve 66 adjusted by driving the actuator. Yes. The larger the opening of the swirl control valve 66, the greater the amount of air taken into the cylinder from the normal port 15a. For this reason, the swirl generated by the swirl port (not shown in FIG. 2) becomes relatively weak, and the inside of the cylinder becomes low swirl (a state where the swirl speed is low). Conversely, the smaller the opening of the swirl control valve 66, the smaller the amount of air drawn into the cylinder from the normal port 15a. For this reason, the swirl generated by the swirl port is relatively strengthened, and the inside of the cylinder becomes a high swirl (a state where the swirl speed is high).

  The exhaust system 7 includes an exhaust manifold 72 connected to the 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. Further, 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 is disposed in the exhaust passage. 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 part 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 (concave portion) 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.

  As for the shape of the cavity 13b, the concave dimension is small in the central portion (on the cylinder center line P), and the concave dimension is increased toward the outer peripheral side. That is, as shown in FIG. 2, when the piston 13 is in the vicinity of the compression top dead center, the combustion chamber 3 formed by the cavity 13b is a narrow space having a relatively small volume at the center portion, and is directed toward the outer peripheral side. Thus, the space is gradually enlarged (expanded space).

  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 which 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 52 and a compressor wheel 53 that are connected via a turbine shaft 51. The compressor wheel 53 is disposed facing the intake pipe 64, and the turbine wheel 52 is disposed facing the exhaust pipe 73. For this reason, the turbocharger 5 performs a so-called supercharging operation in which the compressor wheel 53 is rotated using the exhaust flow (exhaust pressure) received by the turbine wheel 52 to increase the intake pressure. The turbocharger 5 in the present embodiment is a variable nozzle type turbocharger, and a variable nozzle vane mechanism (not shown) is provided on the turbine wheel 52 side. By adjusting the opening of the variable nozzle vane mechanism, the engine 1 supercharging pressure can be adjusted.

  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. The EGR passage 8, the EGR valve 81, the EGR cooler 82, and the like constitute an EGR device (exhaust gas recirculation device).

-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. 3, 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 in the CPU 101, data input from each sensor, and the like. The backup RAM 104 is a non-volatile memory that stores data to be saved when the engine 1 is stopped, for example.

  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 an output shaft of the engine 1. A crank position sensor 40 that outputs a detection signal (pulse) every time the (crankshaft) rotates by a certain angle, an in-cylinder pressure sensor 4A that detects in-cylinder pressure, and the like are connected.

  On the other hand, the output interface 106 includes the supply pump 21, the injector 23, the fuel addition valve 26, the throttle valve 62, the swirl control valve 66, the EGR valve 81, and the variable nozzle vane mechanism of the turbocharger 5 (the opening degree of the variable nozzle vane). Is also connected.

  Then, the ECU 100 executes various controls of the engine 1 based on outputs from the various sensors described above, calculated values obtained by arithmetic expressions using the output values, or various maps stored in the ROM 102. .

  For example, the ECU 100 executes pilot injection (sub-injection) and main injection (main injection) as fuel injection control of the injector 23.

  The pilot injection is an operation for injecting a small amount of fuel in advance prior to the main injection from the injector 23. The pilot injection is an injection operation for suppressing the ignition delay of fuel due to the main injection and leading to stable diffusion combustion, and is also referred to as sub-injection. Further, the pilot injection in the present embodiment has not only a function of suppressing the initial combustion speed by the main injection described above but also a preheating function of increasing the in-cylinder temperature. 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 until the main injection is started to reach the fuel self-ignition temperature (for example, 1000 K). In this way, the ignitability of the fuel injected by the main injection is ensured satisfactorily.

  The main injection is an injection operation (torque generation fuel supply operation) for generating torque of the engine 1. The injection amount in the main injection is basically determined so as to obtain the required torque according to the operation state such as the engine speed, the accelerator operation amount, the coolant temperature, the intake air temperature, 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 larger the accelerator operation amount (the accelerator pedal depression amount detected by the accelerator opening sensor 47). As the accelerator opening becomes larger, the required torque value of the engine 1 is higher, and accordingly, the fuel injection amount in the main injection is also set higher. In addition, when the pre-injection in the cylinder is sufficiently performed by the pilot injection, the fuel injected by the main injection is immediately exposed to a temperature environment equal to or higher than the auto-ignition temperature, and the thermal decomposition proceeds. Will start burning immediately.

  In addition to the pilot injection and main injection described above, after injection and post injection are performed as necessary. After injection is an injection operation for increasing the exhaust gas temperature. Specifically, after injection is performed at a timing at which most of the combustion energy of the supplied fuel is obtained as thermal energy of the exhaust gas without being converted into torque of the engine 1. 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. .

  Further, the ECU 100 controls the opening degree of the EGR valve 81 according to the operating state of the engine 1 to adjust the exhaust gas recirculation amount (EGR amount) toward the intake manifold 63. The EGR amount is set according to an EGR map stored in advance in the ROM 102. Specifically, this EGR map is a map for determining the EGR amount (EGR rate) using the engine speed and the engine load as parameters. This EGR map is created in advance by experiments, simulations, or the like. That is, by applying the engine speed calculated based on the detection value of the crank position sensor 40 and the opening of the throttle valve 62 (corresponding to the engine load) detected by the throttle opening sensor 42 to the EGR map. An EGR amount (opening degree of the EGR valve 81) is obtained.

  Further, the ECU 100 executes the opening degree control of the swirl control valve 66. In order to control the opening degree of the swirl control valve 66, the amount of movement of the fuel spray injected into the combustion chamber 3 per unit time (or per unit crank rotation angle) in the circumferential direction in the cylinder is changed. Is called.

-Fuel injection pressure-
The fuel injection pressure when executing the fuel injection 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. The target rail pressure is set according to a fuel pressure setting map stored in the ROM 102, for example. That is, by determining the fuel pressure according to this fuel pressure setting map, the valve opening period (injection rate waveform) of the injector 23 is controlled, and the fuel injection amount during the valve opening period can be defined.

  In the present embodiment, the fuel pressure is adjusted between 30 MPa and 200 MPa according to the engine load and the like.

  Regarding the fuel injection parameters such as the pilot injection and the main injection, the optimum values differ 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, obtains the amount of depression of the accelerator pedal (accelerator opening) based on the detection value of the accelerator opening sensor 47, The total fuel injection amount (the sum of the injection amount in pilot injection and the injection amount in main injection) is determined based on the engine speed and the accelerator opening.

-Outline of combustion mode-
Next, the outline of the combustion mode in the combustion chamber 3 in the engine 1 according to the present embodiment will be described.

  In FIG. 4, gas (air) is sucked into one cylinder of the engine 1 through the intake manifold 63 and the intake port 15 a, and combustion is performed by fuel injection from the injector 23 into the combustion chamber 3. FIG. 6 is a diagram schematically showing how the subsequent gas is discharged to the exhaust manifold 72 through the exhaust port 71.

  As shown in FIG. 4, the gas sucked into the cylinder includes fresh air sucked from the intake pipe 64 through the throttle valve 62 and from the EGR passage 8 when the EGR valve 81 is opened. Inhaled EGR gas is included. The ratio of the amount of EGR gas to the sum of the amount of fresh air (mass) to be sucked and the amount of mass of EGR (mass) to be sucked (that is, the EGR rate) is appropriately controlled by the ECU 100 according to the operating state. It changes according to the opening degree of 81.

  The fresh air and EGR gas sucked into the cylinder in this way are sucked into the cylinder as the piston 13 (not shown in FIG. 4) descends via the intake valve 16 which is opened in the intake stroke. It becomes in-cylinder gas. This in-cylinder gas is sealed in the cylinder by closing the intake valve 16 when the valve is determined according to the operating state of the engine 1 (in-cylinder gas confinement state), and in the subsequent compression stroke The piston 13 is compressed as the piston 13 moves up. When the piston 13 reaches the vicinity of the top dead center, the injector 23 is opened for a predetermined time by the injection amount control by the ECU 100 described above, so that the fuel is directly injected into the combustion chamber 3. Specifically, the pilot injection is performed before the piston 13 reaches the top dead center, and after the fuel injection is temporarily stopped, the piston 13 reaches the vicinity of the top dead center after a predetermined interval. Main injection will be executed.

  FIG. 5 is a cross-sectional view showing the combustion chamber 3 and its peripheral portion at the time of fuel injection, and FIG. 6 is a plan view of the combustion chamber 3 at the time of fuel injection (a view showing the upper surface of the piston 13). As shown in FIG. 6, the injector 23 of the engine 1 according to the present embodiment is provided with eight injection holes at equal intervals in the circumferential direction, and fuel is injected equally from these injection holes. It has become so. The number of nozzle holes is not limited to eight.

  The fuel sprays A, A,... Injected from the nozzle holes diffuse in a substantially conical shape. In addition, since fuel injection from each nozzle hole (the pilot injection and main injection) is performed when the piston 13 reaches the vicinity of the compression top dead center, as shown in FIG. ,... Diffuses in the cavity 13b.

  As described above, the fuel sprays A, A,... Injected from the respective injection holes formed in the injector 23 are mixed with the in-cylinder gas with the passage of time and become air-fuel mixtures in the cylinder. It diffuses in a conical shape and burns by self-ignition. That is, each of the fuel sprays A, A,... Forms a substantially conical combustion field together with the in-cylinder gas, and combustion is started in each of the combustion fields (eight combustion fields in this embodiment). It will be.

  The energy generated by this combustion is kinetic energy for pushing down the piston 13 toward the bottom dead center (energy serving as engine output), thermal energy for raising the temperature in the combustion chamber 3, cylinder block 11 and cylinder head 15 It becomes the heat energy radiated to the outside (for example, cooling water) through.

  The in-cylinder gas after combustion is discharged to the exhaust port 71 and the exhaust manifold 72 as the piston 13 rises through the exhaust valve 17 that opens in the exhaust stroke, and becomes exhaust gas.

-Driving transient learning control-
Next, the driving transient learning control which is the characteristic feature of this embodiment will be described. This driving transient learning control learns the driving characteristics of the driver who is driving the vehicle (accelerator pedal depression speed during transient driving; driving transient) and controls the engine 1 control parameters ( In-cylinder oxygen concentration, fuel ignition timing, etc.) are controlled.

  In this driving transient learning control, the “driving transient determination operation” for determining the driving characteristics (driving transient) of the driver who is driving the vehicle, and the engine 1 according to the determined driving transient. A “control parameter correction operation” for correcting the control value of the control parameter is performed. Hereinafter, each operation will be described.

(Operation transient judgment operation)
First, the operation transient determination operation will be described. As shown in FIG. 7, the procedure for determining the operation transient degree is as follows: “In-cylinder state quantity reference value Xb” reading operation (step ST1), “actual in-cylinder state quantity Xr” detection operation (step ST2) , “State quantity deviation ΔX” calculation operation (step ST3), “state quantity deviation average value ΔXav e” calculation operation (step ST4), “state quantity change maximum reference value ΔXb-ave ” reading operation (step ST5) ), “Driver Transient Rt (Driver Transient Transient in the Present Invention)” is calculated (step ST6) in order. This operation transient degree determination operation is executed at predetermined time intervals or predetermined crank rotation angles after the engine 1 is started. Hereinafter, each operation will be described in order.

<In-cylinder state quantity reference value Xb reading operation>
The in-cylinder state quantity reference value Xb is adaptive value information of the in-cylinder pressure, the in-cylinder temperature, and the in-cylinder gas composition (oxygen concentration) as the in-cylinder state quantity during the steady operation of the engine 1. This information is based on various steady-state operations according to the required engine speed and the engine load (the engine speed and the engine load are substantially constant) in the actual engine operating state by a vehicle tester such as a chassis dynamometer or an engine bench tester. In-cylinder acquired when various control parameters (fuel injection amount, fuel injection timing, fuel injection pressure, EGR rate, etc.) of the engine 1 in the steady operation are adapted. Pressure, temperature in the cylinder, and gas composition in the cylinder. Further, it may be information on the pressure in the cylinder, the temperature in the cylinder, and the gas composition in the cylinder in the conforming state in each steady operation by computer simulation.

  More specifically, steady operation is performed in a state where various control parameters of the engine 1 are adapted so that the exhaust emission and the fuel consumption rate both satisfy the required values, and in that operating state, the piston 13 is compression top dead center. In-cylinder state quantity reference based on these values by measuring or estimating in-cylinder pressure, in-cylinder temperature, and in-cylinder gas composition (oxygen concentration) when (TDC; Top Dead Center) is reached. The value Xb is acquired. As the in-cylinder state quantity reference value Xb, individual in-cylinder state quantity reference values Xb may be obtained for each of the pressure in the cylinder, the temperature in the cylinder, and the gas composition in the cylinder. One in-cylinder state quantity reference value for each steady operation using a predetermined calculation formula or a map created in advance from two or all of the information on the pressure in the cylinder, the temperature in the cylinder, and the gas composition in the cylinder Xb may be obtained. In the case of obtaining individual in-cylinder state quantity reference values Xb for the in-cylinder pressure, the in-cylinder temperature, and the in-cylinder gas composition, the in-cylinder state calculation value and the reading operation described later are also included in the in-cylinder state amount reference value Xb. The pressure, the temperature in the cylinder, and the gas composition in the cylinder are individually performed.

  The timing for measuring or estimating the information (in-cylinder pressure, in-cylinder temperature, in-cylinder gas composition) is not limited to the point in time when the piston 13 reaches the compression top dead center. It may be the time when injection is started or the time when the intake valve 16 changes from the open state to the closed state (the time when the in-cylinder gas becomes confined). As a technique for measuring or estimating the pressure in the cylinder, the temperature in the cylinder, and the gas composition in the cylinder, conventionally known techniques can be employed. For example, it is measured based on detection signals from various sensors, or is estimated from the detected intake air amount, the fuel injection amount according to the control instruction value, the compression ratio that is the specification of the engine 1, and the like.

  These measured or estimated in-cylinder pressure, in-cylinder temperature, and in-cylinder gas composition change greatly under the influence of combustion when combustion is started in the cylinder. In order to handle the in-cylinder state quantity reference value Xb as an index common to the operation, it is preferable to obtain the in-cylinder state quantity reference value Xb as a value in a gas state not affected by combustion. For this reason, this in-cylinder state quantity reference value Xb is obtained when fuel combustion has not yet started, or on the assumption that fuel combustion is not performed. For example, when the time when the piston 13 reaches the compression top dead center is set as the information acquisition timing, each information is acquired in a state where the combustion of the fuel is not started when the piston 13 reaches the compression top dead center. Or when it is assumed that combustion of fuel (for example, combustion of fuel injected by pilot injection) has not started when the piston 13 reaches compression top dead center (intake air amount, fuel injection amount, Each information is acquired by estimating the pressure in the cylinder, the temperature in the cylinder, and the gas composition in the cylinder when the piston 13 reaches the compression top dead center from the compression ratio or the like. Further, when the fuel injection start timing from the injector 23 is set as the information acquisition timing, it is a condition that the preceding fuel injection or fuel combustion is not performed in the same combustion stroke. For example, when pilot injection is executed prior to main injection, the start time of this pilot injection is set as the acquisition timing of this information, and when pilot injection is not executed, the start time of main injection is It will be set as the acquisition timing. Further, even when pilot injection is executed, the pressure in the cylinder, the temperature in the cylinder, and the gas composition in the cylinder at the start of the main injection are estimated on the assumption that combustion by the pilot injection is not performed. You may do it.

  These pieces of information (in-cylinder state quantity reference value Xb in-cylinder pressure, in-cylinder temperature, in-cylinder gas composition information) are stored in the ROM 102 in advance. Therefore, in the operation of reading the in-cylinder state quantity reference value Xb, the information on the steady operation that matches the current operation state (the operation state determined by the required rotational speed and the engine load) during the operation of the engine 1 is described above. The data is read from the ROM 102. That is, information on the assumption that the current operation state (the operation state determined by the required rotation speed and the engine load) is a steady operation state is read from the ROM 102. Specifically, the current engine speed is calculated based on the detected value of the crank position sensor 40, and the current accelerator opening (corresponding to the engine load) is detected from the accelerator opening sensor 47, and these engines are detected. The in-cylinder pressure, the in-cylinder temperature, and the in-cylinder gas composition are read from the ROM 102 as the in-cylinder state quantity reference value Xb during steady operation at the rotational speed and the accelerator opening.

  The in-cylinder state quantity reference value Xb is not limited to all information on the in-cylinder pressure, the in-cylinder temperature, and the in-cylinder gas composition, and may be one or two of these pieces of information. .

<Detection Operation of Actual In-Cylinder State Quantity Xr>
The actual in-cylinder state quantity Xr is information on the in-cylinder pressure, the in-cylinder temperature, and the in-cylinder gas composition (oxygen concentration) as the in-cylinder state quantity in the actual operating state of the engine 1. These pieces of information are detected from detection signals from various sensors, or estimated from intake air amount, fuel injection amount, compression ratio, and the like. For example, the in-cylinder pressure is calculated based on the detection signal of the in-cylinder pressure sensor 4A, the detection signal of the intake pressure sensor 48, the compression ratio, and the like. The temperature in the cylinder is calculated based on the detection signal of the intake air temperature sensor 49 and the compression ratio. Further, the gas composition in the cylinder is calculated based on the intake air amount detected by the air flow meter 43 and the current opening degree of the EGR valve 81 set according to the EGR map. Moreover, you may make it use the oxygen concentration estimation method as disclosed by Unexamined-Japanese-Patent No. 2009-30453. Further, the pressure in the cylinder, the temperature in the cylinder, and the gas composition in the cylinder may be measured or estimated by other known methods.

  The acquisition timing of this information coincides with the acquisition timing of the in-cylinder state quantity reference value Xb described above. That is, when the acquisition timing of the in-cylinder state quantity reference value Xb is the time when the piston 13 reaches the compression top dead center, the acquisition timing of the actual in-cylinder state quantity Xr is also the compression top dead center of the piston 13. When the time is reached. When the acquisition timing of the in-cylinder state quantity reference value Xb is the time when fuel injection is started from the injector 23, the acquisition timing of the actual in-cylinder state quantity Xr is also started from the injector 23. And when Further, when the acquisition timing of the in-cylinder state quantity reference value Xb is the time when the intake valve 16 changes from the open state to the closed state, the acquisition timing of the actual in-cylinder state quantity Xr is also the intake valve 16. Is the time when the valve is opened from the open state.

  The other information acquisition timing may be the ignition timing of the fuel injected in the main injection. Also in this case, it is a condition that fuel injection or fuel combustion preceding the ignition timing of the fuel injected in the main injection is not performed in the same combustion stroke. Further, when the main injection is multistage injection, it is the ignition timing of the fuel injected by the first main injection on the most advanced side. In this case as well, it is a condition that fuel injection or fuel combustion preceding the ignition timing of the fuel injected in the first main injection is not performed in the same combustion stroke. In this way, by eliminating the influence of the preceding fuel combustion or the like, it is possible to purely determine the transient as the in-cylinder gas state.

  If it is difficult to install the in-cylinder pressure sensor 4A or there is a possibility that sufficient detection accuracy may not be obtained, the intake air temperature at the time when the intake valve 16 changes from the open state to the closed state or Various information may be acquired in consideration of cooling loss such as a change in the polytropic index during the compression stroke using the intake pressure.

  Further, as in the case of the in-cylinder state quantity reference value Xb described above, the actual in-cylinder state quantity Xr is not limited to all information on the in-cylinder pressure, the in-cylinder temperature, and the in-cylinder gas composition. One or two pieces of information may be used.

<Calculation of state quantity deviation ΔX>
The state quantity deviation ΔX from the in-cylinder state quantity reference value Xb acquired by the reading operation of the in-cylinder state quantity reference value Xb and the actual in-cylinder state quantity Xr acquired by the detection operation of the actual in-cylinder state quantity Xr. Is calculated. This calculation operation of the state quantity deviation ΔX is to obtain a deviation (deviation amount) of the in-cylinder state quantity in the current operating state of the engine 1 with respect to the in-cylinder state quantity in the adapted steady operation. In other words, in the case of transient operation, the actual in-cylinder state quantity deviates from the in-cylinder state quantity in the steady operation by the control delay, and the deviation amount increases as the operating transient degree increases. Therefore, by detecting this, it is determined whether the current operation state of the engine 1 is a steady operation or a transient operation, and if it is a transient operation, the magnitude of the operation transient is determined, and the index As described above, the state quantity deviation ΔX is obtained.

  Specifically, the state quantity deviation ΔX is calculated by the following equation (1).

State quantity deviation ΔX = cylinder state quantity reference value Xb−actual cylinder state quantity Xr (1)
That is, when the current operation state of the engine 1 is a steady operation, there is no control parameter delay or the like, so the actual in-cylinder state quantity Xr corresponding to the requested engine speed and the engine load is in-cylinder. It becomes substantially equal to the state quantity reference value Xb, and the state quantity deviation ΔX is “0” or a relatively small value.

  On the other hand, when the current operation state of the engine 1 is a transient operation, the value representing the actual in-cylinder state with respect to the in-cylinder state amount reference value Xb corresponding to the required engine speed and the engine load. The actual in-cylinder state quantity Xr is a small value (a small value corresponding to a control delay (for example, a delay in changing the opening of the EGR valve 81)). As the driver's driving transient degree increases, the in-cylinder state quantity (target in-cylinder state quantity) corresponding to the required engine speed and the engine load is more different from the in-cylinder state quantity before the start of transient operation. Therefore, when the control delay occurs, the actual in-cylinder state relative to the in-cylinder state quantity (target in-cylinder state quantity) corresponding to the required engine speed and engine load increases as the driver's driving transient degree increases. The deviation of the state quantity Xr increases. As a result, when the driver's driving transient degree is relatively small, the state quantity deviation ΔX is also calculated as a relatively small value, while when the driver's driving transient degree is relatively large, the state quantity deviation The deviation ΔX is also calculated as a relatively large value.

  FIG. 8 shows changes in the accelerator opening during transient operation of the engine 1, changes in the target oxygen concentration corresponding to the in-cylinder state quantity reference value Xb, and changes in the actual oxygen concentration corresponding to the actual in-cylinder state quantity Xr. FIG. 8A shows a case where the change rate of the accelerator opening is relatively low, and FIG. 8B shows a case where the change rate of the accelerator opening is relatively high. In FIG. 8A, depression of the accelerator pedal is started at timing t1, and a predetermined accelerator opening (after transition from transient operation to steady operation is performed at timing t3, in which the elapsed time from timing t1 is relatively long. Accelerator opening) has been reached. On the other hand, in FIG. 8B, the depression of the accelerator pedal is started at the timing t1, and the predetermined accelerator opening (the transition from the transient operation to the steady operation is performed at the timing t2 in which the elapsed time from the timing t1 is relatively short. The later accelerator opening) has been reached. In the oxygen concentration change, the solid line in the figure indicates the change in the target oxygen concentration, and the alternate long and short dash line indicates the change in the actual oxygen concentration.

  As shown in FIG. 8 (a), when the change rate of the accelerator opening is relatively low, the change rate of the target oxygen concentration is also low, and even if there is a delay in changing the opening of the EGR valve 81, this EGR valve The difference between the in-cylinder oxygen concentration (actual oxygen concentration) and the target oxygen concentration that are changed according to the opening of 81 is relatively small. For example, at the timing t2 in the figure, the deviation between the actual oxygen concentration and the target oxygen concentration is ΔX1 in the figure, and this ΔX1 is the state quantity deviation ΔX when the change rate of the accelerator opening is relatively low. It corresponds to.

  On the other hand, as shown in FIG. 8B, when the change rate of the accelerator opening is relatively high, the change rate of the target oxygen concentration is also high, and when the change in the opening of the EGR valve 81 is delayed. The difference between the in-cylinder oxygen concentration (actual oxygen concentration) and the target oxygen concentration, which are changed according to the opening degree of the EGR valve 81, is relatively large. For example, at the timing t2 in the figure, when the change rate of the accelerator opening is relatively low as described above, ΔX1 in the figure is a relatively small value, but the change rate of the accelerator opening is high. Is a relatively large value, ΔX2 in the figure. ΔX2 in this figure corresponds to the state quantity deviation ΔX when the change rate of the accelerator opening is relatively high. As described above, the higher the change rate of the accelerator opening (the higher the operation transient degree), the larger the state quantity deviation ΔX is calculated. In other words, this state quantity deviation ΔX is calculated as an index representing the degree of transient of the driver's accelerator operation.

  In FIG. 8, the change in the accelerator opening, the change in the target oxygen concentration, and the change in the actual oxygen concentration during the transient operation of the engine 1 have been described. However, a control delay of the in-cylinder pressure occurs during the transient operation of the engine 1. Even when a control delay of the in-cylinder temperature occurs, the value corresponding to the state quantity deviation ΔX differs according to the change rate of the accelerator opening, as described above.

  The state quantity deviation ΔX may be calculated by the following equation (2) in consideration of a temporal average.

State quantity deviation ΔX = (in-cylinder state quantity reference value Xb−actual in-cylinder state quantity Xr) / Δt (2)
In this case, Δt = 1 / {(Ne / 60) × 2π} (3)
Ne is the engine speed (rpm).

  In this case as well, the higher the change rate of the accelerator opening (the higher the driving transient degree), the larger the state quantity deviation ΔX is calculated. Therefore, this state quantity deviation ΔX is calculated by the driver's accelerator. It is calculated as an index representing the transient degree of operation.

<Calculation of State Quantity Deviation Average Value ΔXave>
After the state quantity deviation ΔX is obtained as described above, this time using the average value of the state quantity deviation ΔX calculated in the past (the previous value of the state quantity deviation average value ΔXave) and the current state quantity deviation ΔX. The state quantity deviation average value ΔXave of is calculated.

  Specifically, the state quantity deviation average value ΔXave is calculated by the following equation (4).

State quantity deviation average value ΔXave = (State quantity deviation average value ΔXave (previous value) + state quantity deviation ΔX (current value)) / 2 (4)
Here, the state quantity deviation average value ΔXave as the previous value is the state quantity deviation average value ΔXave calculated in the routine up to the previous time in the routine of FIG. This value represents an indicator of the driver's driving transient during the period up to the previous routine. The state quantity deviation average value ΔXave as the previous value may be an average value of the state quantity deviation ΔX over the entire period of past travel of the vehicle, or a predetermined travel distance (for example, 1 The average value of the state quantity deviation ΔX during the traveling period of 10,000 km) may be used.

  In the above equation (4), the state quantity deviation average value ΔXave in which the current state quantity deviation ΔX is reflected on the state quantity deviation average value ΔXave as the previous value (reflected by the annealing calculation) is obtained. . That is, when the current state quantity deviation ΔX is larger than the state quantity deviation average value ΔXave calculated in the routine up to the previous time, that is, when the change rate of the current accelerator opening is higher than the past average value. The state quantity deviation average value ΔXave calculated by the above equation (4) is a large value. On the other hand, when the current state quantity deviation ΔX is smaller than the state quantity deviation average value ΔXave calculated in the previous routine, that is, when the change rate of the current accelerator opening is lower than the past average value. The state quantity deviation average value ΔXave calculated by the above equation (4) is a small value.

<Reading operation of state quantity change maximum reference value ΔXb-ave>
The state quantity change maximum reference value ΔXb-ave is an indicator of excessive operation that becomes a reference when the transient operation of the engine 1 is performed.

  Specifically, for example, when the target vehicle is European specification, the case where the vehicle is driven in the European test mode (EC mode) becomes the reference transient degree and the state quantity change maximum reference value ΔXb. -ave is specified. In other words, the actual in-cylinder state quantity Xr when the vehicle is driven in the test mode defined in Europe is obtained in the same manner as the above-described detection operation of the in-cylinder state quantity Xr. The state quantity deviation ΔX in the mode is obtained in the same manner as the calculation operation of the state quantity deviation ΔX described above, and this is set as the state quantity change maximum reference value ΔXb-ave. As a result, the driver's driving transient (standard driving transient) when the vehicle is driven in the European test mode is acquired.

  In addition, the state quantity change maximum reference value ΔXb-ave obtained by running in this European test mode is multiplied by a safety factor that takes into account the ease of changes in transients due to component tolerances, and is thus obtained. The obtained value may be set as the state quantity change maximum reference value ΔXb-ave. That is, since the ease of change of the transient degree differs depending on the inertia of each component, the state quantity change maximum reference value ΔXb-ave is set in consideration of this.

  The test mode (vehicle running test mode) is not limited to the above-described European test mode (EC mode), but can be any mode such as 10.15 mode, JC08 mode, diesel 13 mode, US LA-4 mode ( For example, a test mode defined in the sales country targeted by the vehicle can be employed.

  Further, not only the test mode described above (specified test mode) but also standard driving characteristics of the vehicle driver are specified by the vehicle manufacturer, and the state quantity change maximum reference value ΔXb-ave is determined according to the specified driving characteristics. Or the state quantity change maximum reference value ΔXb-ave may be defined according to the average driving characteristics of a large number of drivers.

<Calculation operation of driver transient Rt>
From the state quantity deviation average value ΔXave obtained by the calculation operation of the state quantity deviation average value ΔXave and the state quantity change maximum reference value ΔXb-ave obtained by the reading operation of the state quantity change maximum reference value ΔXb-ave. A driver transient degree Rt is calculated. Whether the driver transient degree Rt is higher than the reference driving transient degree (corresponding to the state quantity change maximum reference value ΔXb-ave) is higher than the actual driving transient degree (corresponding to the state quantity deviation average value ΔXave). It is what you want. In other words, it is determined whether the actual operating transient is higher than the operating transient in the specified test mode (European test mode in the above case). The degree of deviation of the actual driving transient from the driving transient in the test mode is calculated as the driver transient Rt.

  Specifically, the driver transient degree Rt is calculated by the following equation (5).

Driver transient Rt =
State quantity deviation average value ΔXave / state quantity change maximum reference value ΔXb-ave (5)
Accordingly, the driver transient degree Rt is calculated as the ratio of the state quantity deviation average value ΔXave to the state quantity change maximum reference value ΔXb-ave. Therefore, if the state quantity deviation average value ΔXave matches the state quantity change maximum reference value ΔXb-ave, the driver transient Rt is calculated as “1”, and the state quantity deviation average value ΔXave is calculated as the state quantity. When the change maximum reference value ΔXb-ave is larger, the driver transient Rt is calculated as “a value greater than 1”, and the state quantity deviation average value ΔXave is smaller than the state quantity change maximum reference value ΔXb-ave. In this case, the driver transient degree Rt is calculated as “a positive value smaller than 1”.

  Further, the driver transient degree Rt may be calculated by the following equation (6).

Driver transient Rt =
State quantity deviation average value ΔXave−state quantity change maximum reference value ΔXb-ave (6)
Thus, the driver transient degree Rt is calculated as the difference (deviation) between the state quantity change maximum reference value ΔXb-ave and the state quantity deviation average value ΔXave. Therefore, if the state quantity deviation average value ΔXave matches the state quantity change maximum reference value ΔXb-ave, the driver transient Rt is calculated as “0”, and the state quantity deviation average value ΔXave is calculated as the state quantity. When the change maximum reference value ΔXb-ave is larger than the maximum change amount reference value ΔXb-ave, the driver transient degree Rt is calculated as a “positive value”, and when the state quantity deviation average value ΔXave is smaller than the state quantity change maximum reference value ΔXb-ave. Therefore, the driver transient degree Rt is calculated as a “negative value”.

  By performing the driving transient determination operation as described above, the driver transient Rt as a value corresponding to the driving characteristics (driving transient) of the driver is calculated.

(Control parameter correction operation)
Next, a control parameter correction operation using the driver transient degree Rt calculated by the above-described driving transient degree determination operation will be described. As this control parameter correction operation, an operation for correcting the in-cylinder oxygen concentration (hereinafter referred to as “in-cylinder oxygen concentration correction operation”) and an operation for correcting the control parameters for both the in-cylinder oxygen concentration and the fuel ignition timing ( Hereinafter, it is referred to as “multiple control parameter correction operation”).

  Hereinafter, “cylinder oxygen concentration correction operation” will be described as the first embodiment, and “multiple control parameter correction operation” will be described as the second embodiment.

  In the following embodiments, a case where the driver transient degree Rt is calculated as a ratio of the state quantity deviation average value ΔXave to the state quantity change maximum reference value ΔXb-ave will be mainly described. That is, when the state quantity deviation average value ΔXave matches the state quantity change maximum reference value ΔXb-ave, the driver transient Rt is calculated as “1”, and the state quantity deviation average value ΔXave is changed to the state quantity change. When it is larger than the maximum reference value ΔXb-ave, the driver transient Rt is calculated as “a value greater than 1”, and the state quantity deviation average value ΔXave is smaller than the state quantity change maximum reference value ΔXb-ave. In this case, the driver transient degree Rt is calculated as “a positive value smaller than 1”.

<First Embodiment>
First, a first embodiment in which the in-cylinder oxygen concentration is corrected using the driver transient degree Rt will be described. As an outline of the in-cylinder oxygen concentration correction operation, when the driver transient degree Rt is calculated as “1” or “a value greater than 1,” the driving transient degree is relatively high. The opening degree of the EGR valve 81 is set to be relatively small so as to increase the in-cylinder oxygen concentration on the assumption that the depression speed of the accelerator pedal by the driver is relatively high. Thereby, the opening degree control of the EGR valve 81 (control for reducing the opening degree of the EGR valve 81) at the time of transition from the engine operating point with the accelerator opening degree being small to the engine operating point with the accelerator opening degree being large. Even if a delay occurs, it is possible to prevent misfires by ensuring a sufficient in-cylinder oxygen concentration.

  On the other hand, when the driver transient degree Rt is calculated as “a positive value smaller than 1”, the driver transient degree is relatively low, that is, the accelerator pedal depression speed by the driver is relatively low. As the driver transient degree Rt is smaller, the opening degree of the EGR valve 81 is set to be relatively large so that the in-cylinder oxygen concentration is lowered. As a result, misfires are not caused during transient operation (transient operation where the accelerator pedal depression speed is relatively low), and the exhaust gas emission is improved (by reducing the NOx generation amount) by setting the oxygen concentration in the cylinder lower. Reduction).

  FIG. 9 is a flowchart showing the procedure of the in-cylinder oxygen concentration correction operation in the present embodiment. This in-cylinder oxygen concentration correction operation is executed every time the driver transient degree Rt is calculated by the above-described driving transient degree determining operation.

  First, in step ST11, the driver transient degree Rt is read. That is, the driver transient degree Rt calculated by the driving transient degree determining operation is read.

  Thereafter, the process proceeds to step ST12, and it is determined whether or not the travel distance of the vehicle has reached the “transient update distance”. This is to prevent the target value of the in-cylinder oxygen concentration from changing in a short period. Although an arbitrary value can be set as this transient degree update distance, it is set as a sufficiently long distance (for example, 1000 km) compared to the travel distance defined in the test mode.

If the travel distance of the vehicle has not reached the “transient update distance” and a NO determination is made in step ST12, the process is temporarily returned. When the travel distance of the vehicle reaches the “transient degree update distance” and a YES determination is made in step ST12, the process proceeds to step ST13, where the oxygen concentration target correction value is calculated. Specifically, the oxygen concentration target correction value ΔO ₂ is calculated according to the oxygen concentration target correction value map shown in FIG. This oxygen concentration target correction value map defines the relationship between the driver transient degree Rt and the oxygen concentration target correction value ΔO ₂ . Specifically, when the driver transient Rt is “1” or more, the oxygen concentration target correction value ΔO ₂ is set to “0”. That is, the in-cylinder oxygen concentration is not corrected. On the other hand, when the driver transient Rt is less than “1”, the oxygen concentration target correction value ΔO ₂ is set to be larger as the driver transient Rt is smaller. This oxygen concentration target correction value ΔO ₂ defines the subtraction amount of the oxygen concentration with respect to the current in-cylinder oxygen concentration. For this reason, as the oxygen concentration target correction value ΔO ₂ is set larger, the target value of the in-cylinder oxygen concentration is set smaller. In other words, the in-cylinder oxygen concentration is set low by increasing the opening degree of the EGR valve 81 and increasing the recirculation amount of the exhaust gas.

After obtaining the oxygen concentration target correction value ΔO ₂ from the oxygen concentration target correction value map in this way, the process proceeds to step ST14, where the in-cylinder oxygen concentration target value is calculated. As described above, since the oxygen concentration target correction value ΔO ₂ defines the subtraction amount of the oxygen concentration with respect to the current in-cylinder oxygen concentration, the in-cylinder oxygen concentration target value is calculated using the following equation (7). Is done by.

O _2trg = O _2trgb −ΔO ₂ (7)
Here, O _2trg is the updated in-cylinder oxygen concentration target value, O _2trgb is the in-cylinder oxygen concentration target value before the update, and ΔO ₂ is the oxygen concentration target correction value obtained in step ST13.

  After the in-cylinder oxygen concentration target value is calculated in this way, the process proceeds to step ST15, and the opening degree of the EGR valve 81 is controlled so that the in-cylinder oxygen concentration target value is obtained. That is, control is performed so that the opening degree of the EGR valve 81 is reduced as the in-cylinder oxygen concentration target value increases.

  As described above, the driving characteristics of the driver who is driving the vehicle (accelerator pedal depression speed during transient operation; driving transient degree) are learned, and the control parameters of the engine 1 ( In-cylinder oxygen concentration) is controlled.

  Conventionally, regardless of the driver's driving characteristics, the controlled variable is adjusted so as not to cause misfire even if a control delay occurs, so driving with low driving characteristics (for example, accelerator pedal depression speed is relatively low) When the driver is driving, even if the oxygen concentration in the cylinder is set higher than necessary and the oxygen concentration in the cylinder is set lower, the transient operation (transient with a relatively low accelerator pedal depression speed) In spite of not causing misfire during operation, the oxygen concentration in this cylinder can be set lower to improve exhaust emissions (reduce NOx generation) and improve fuel consumption. In spite of the above, the oxygen concentration capable of exhibiting such an effect was not set.

  In this embodiment, by learning the driving characteristics of the driver and controlling the engine control parameter (in-cylinder oxygen concentration) in accordance with the learned driving characteristics, the control parameter can be optimized, resulting in misfire. In addition, by making it possible to set the oxygen concentration in the cylinder lower, it is possible to improve exhaust emission (reduction of NOx generation amount) and fuel consumption rate.

  Further, along with the reduction in the amount of NOx generated, the frequency of use of the fuel addition valve 26 described above is reduced to reduce fuel consumption, or the fuel addition system including the fuel addition valve 26 and the added fuel passage 28 is abolished. It is possible to do. In addition, in the case of a device equipped with a well-known urea addition system, it is possible to reduce the consumption frequency of the urea additive by reducing the frequency of use or to eliminate the system.

When the driver transient degree Rt is calculated as the difference between the state quantity change maximum reference value ΔXb-ave and the state quantity deviation average value ΔXave, the oxygen concentration target correction is performed according to the oxygen concentration target correction value map shown in FIG. The value ΔO ₂ is calculated. This oxygen concentration target correction value map also defines the relationship between the driver transient degree Rt and the oxygen concentration target correction value ΔO ₂ . Specifically, when the driver transient Rt is “0” or more, the oxygen concentration target correction value ΔO ₂ is set to “0”. That is, the in-cylinder oxygen concentration is not corrected. On the other hand, when the driver transient degree Rt is less than “0”, the smaller the driver transient degree Rt, the larger the oxygen concentration target correction value ΔO ₂ is set. The calculation operation of the in-cylinder oxygen concentration target value based on the oxygen concentration target correction value ΔO ₂ and the opening degree control of the EGR valve 81 based on the in-cylinder oxygen concentration target value are the same as those described above. Is omitted.

  Thus, even when the driver transient degree Rt is calculated as the difference between the state quantity change maximum reference value ΔXb-ave and the state quantity deviation average value ΔXave, as described above (the driver transient degree Rt The same effect as in the case of calculating the ratio of the state quantity deviation average value ΔXave to the maximum change reference value ΔXb-ave) can be obtained.

Second Embodiment
Next, a second embodiment will be described. In the present embodiment, another control parameter correction operation (fuel ignition timing correction operation) is added to the control parameter correction operation (in-cylinder oxygen concentration correction operation) of the first embodiment described above.

  As an outline of the control parameter correction operation in the present embodiment, first, as in the case of the first embodiment described above, the in-cylinder oxygen concentration target value is obtained, and the opening degree of the EGR valve 81 is controlled accordingly. In addition, when the driver transient degree Rt is calculated as “1” or “a value greater than 1” (the driver transient degree Rt is the state quantity deviation average with respect to the state quantity change maximum reference value ΔXb-ave) When the driver transient degree Rt is calculated as “1” or “a value greater than 1” when calculated as the ratio of the value ΔXave), the driver transient degree is relatively high, that is, the driver The fuel injection of the injector is controlled so that the fuel ignition timing is shifted to the retard side, assuming that the accelerator pedal depressing speed is relatively high.

  On the other hand, when the driver transient degree Rt is calculated as “a positive value smaller than 1”, the driver transient degree is relatively low, that is, the accelerator pedal depression speed by the driver is relatively low. The fuel injection of the injector is controlled so that the fuel ignition timing is shifted to the advance side. This prevents misfire during transient operation (transitional operation with a relatively low accelerator pedal depression speed) and improves the fuel consumption rate by setting the fuel ignition timing to the advance side. ing.

  FIG. 12 is a flowchart showing the procedure of the control parameter correction operation in the present embodiment. This control parameter correction operation is executed every time the driver transient degree Rt is calculated by the above-described driving transient degree determining operation.

  The operations in steps ST11 to ST15 in FIG. 12 are the same as the operations in steps ST11 to ST15 in FIG. 9 of the first embodiment described above, and thus the description thereof is omitted here.

  After the opening degree of the EGR valve 81 is controlled in step ST15, the process proceeds to step ST16, and the ignition timing target correction value is calculated. Specifically, the ignition timing target correction value Δθ is calculated according to the ignition timing target correction value map shown in FIG. This ignition timing target correction value map defines the relationship between the driver transient degree Rt and the ignition timing target correction value Δθ. Specifically, when the driver transient Rt is “1” or more, the ignition timing target correction value Δθ is set to “0”. That is, the ignition timing is not corrected. On the other hand, when the driver transient degree Rt is less than “1”, the ignition timing target correction value Δθ is set larger as the driver transient degree Rt is smaller. This ignition timing target correction value Δθ defines a correction amount for correcting the current ignition timing to the advance side. For this reason, as the ignition timing target correction value Δθ is set larger, the ignition timing is set to the advance side. For example, the ignition timing is set to the advance side by correcting the fuel injection timing of the injector 23 to the advance side.

  After obtaining the ignition timing target correction value Δθ from the ignition timing target correction value map in this way, the process proceeds to step ST17, where the ignition timing target value is calculated. As described above, since the ignition timing target correction value Δθ defines a correction amount for correcting the current ignition timing to the advance side, the calculation of the ignition timing target value is performed by the following equation (8). Is called.

θ _trg = θ _trgb −Δθ (8)
Here, θ _trg is the updated ignition timing target value, θ _trgb is the ignition timing target value before the update, and Δθ is the ignition timing target correction value obtained in step ST17.

  After the ignition timing target value is calculated in this way, the process proceeds to step ST18, and the injector 23 is controlled so that this ignition timing target value is obtained.

  Specifically, the control of the injector 23 for obtaining the ignition timing target value includes control of fuel injection timing, fuel injection amount, and fuel injection pressure. For example, when the ignition timing target value is corrected to the advance side, the fuel injection timing is corrected to the advance side, or the fuel injection amount and the fuel injection pressure are corrected so as to form a combustion field that is easy to burn. Or Specifically, by increasing the injection amount of pilot injection to increase the in-cylinder preheating amount, the ignition timing of fuel injected by main injection is corrected to the advance side, or the excess air ratio in the combustion field is high In some cases, the fuel injection pressure is corrected to be low so that the excess air ratio is optimized (a combustion field that easily ignites) is formed.

  As described above, the driving characteristics of the driver who is driving the vehicle (accelerator pedal depression speed during transient operation; driving transient degree) are learned, and the control parameters of the engine 1 ( In-cylinder oxygen concentration and ignition timing) are controlled.

  As described above, in this embodiment as well, in the same manner as in the first embodiment, the driver's driving characteristics are learned, and the engine control parameters (in-cylinder oxygen concentration and ignition timing) are determined according to the learned driving characteristics. By controlling the engine, this control parameter can be optimized, without causing misfire, and by making it possible to set the oxygen concentration in the cylinder lower, exhaust emission is improved (reducing NOx generation) and fuel consumption It becomes possible to improve the rate.

  Also in the present embodiment, the frequency of use of the fuel addition valve 26 can be reduced, or the fuel addition system including the fuel addition valve 26 and the added fuel passage 28 can be eliminated. In addition, even with a known urea addition system, it is possible to reduce the frequency of use or abolish the system.

  When the driver transient degree Rt is calculated as the difference between the state quantity change maximum reference value ΔXb-ave and the state quantity deviation average value ΔXave, the ignition timing target correction is performed according to the ignition timing target correction value map shown in FIG. The value Δθ is calculated. This ignition timing target correction value map also defines the relationship between the driver transient degree Rt and the ignition timing target correction value Δθ. Specifically, when the driver transient degree Rt is “0” or more, the ignition timing target correction value Δθ is set to “0”. That is, the ignition timing is not corrected. On the other hand, when the driver transient degree Rt is less than “0”, the ignition timing target correction value Δθ is set larger as the driver transient degree Rt is smaller. Since the calculation operation of the ignition timing target value based on this ignition timing target correction value Δθ and the fuel injection control of the injector 23 based on this ignition timing target value are the same as those described above, description thereof will be omitted here.

  Thus, even when the driver transient degree Rt is calculated as the difference between the state quantity change maximum reference value ΔXb-ave and the state quantity deviation average value ΔXave, as described above (the driver transient degree Rt The same effect as in the case of calculating the ratio of the state quantity deviation average value ΔXave to the maximum change reference value ΔXb-ave) can be obtained.

  FIG. 15 is a diagram for explaining changes in the NOx emission amount and the fuel consumption rate in the second embodiment. When the control of the second embodiment is not executed, the NOx emission amount is the limit amount of the NOx emission restriction value as indicated by I in the figure.

  In this state, when the driver's driving transient is low (when the driver transient Rt is small), first, an in-cylinder oxygen concentration correction operation (the operation from step ST13 to step ST15 in FIG. 12) is executed. Thus, when the in-cylinder oxygen concentration is corrected (corrected toward the side where the in-cylinder oxygen concentration is lowered), the NOx emission amount is reduced (see state II in the figure). In this case, there is a possibility that the fuel consumption rate slightly deteriorates due to a slight deterioration of combustion due to a lack of in-cylinder oxygen concentration.

  Then, by executing the ignition timing correction operation (the operation from step ST16 to step ST18 in FIG. 12) and correcting the ignition timing (correcting the ignition timing to the advance side), the fuel consumption rate is improved by improving combustion. (See state III in the figure). In this case, since the combustion temperature rises with the improvement of combustion, the NOx emission amount may be slightly deteriorated. 15 indicates the relationship between the fuel consumption rate and the NOx emission amount before the ignition timing correction operation (in the above-mentioned correction of the in-cylinder oxygen concentration, the fuel consumption rate and the NOx emission amount correspond to this line. 1), the alternate long and short dash line β indicates the relationship between the fuel consumption rate and the NOx emission amount after the ignition timing correction operation.

  As described above, according to this embodiment, by performing the correction operation of the in-cylinder oxygen concentration and the correction operation of the fuel ignition timing, it is possible to shift from the state I to the state III in FIG. It is possible to achieve both a reduction in fuel consumption and an improvement in fuel consumption rate.

-Other embodiments-
Each embodiment described above demonstrated the case where this invention was applied to the in-line 4 cylinder diesel engine mounted in a motor vehicle. 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, horizontally opposed engine, etc.) are not particularly limited.

  In the second embodiment, both the in-cylinder oxygen concentration correction operation and the fuel ignition timing correction operation are performed as the control parameter correction operation. The present invention is not limited to this, and only the correction operation of the fuel ignition timing may be performed without performing the correction operation of the in-cylinder oxygen concentration. However, in this case, since the NOx emission amount may slightly increase, it is necessary to keep the NOx emission amount after the increase below the emission amount regulation value. Further, the correction operation of the in-cylinder oxygen concentration may be performed after the execution of the fuel ignition timing correction operation.

  Further, the correction operation of the in-cylinder oxygen concentration in each of the above embodiments is to control the opening degree of the EGR valve 81. The present invention is not limited to this, and the in-cylinder oxygen concentration correction operation may be performed by controlling the variable nozzle vane mechanism 54 of the supercharger 5. Specifically, when the driver transient degree Rt is relatively large and the in-cylinder oxygen concentration needs to be increased, the opening degree of the nozzle vane in the variable nozzle vane mechanism 54 is decreased to increase the supercharging efficiency. On the contrary, when the driver transient degree Rt is relatively small and it is allowed to reduce the in-cylinder oxygen concentration, the opening degree of the nozzle vane in the variable nozzle vane mechanism 54 is increased and the supercharging efficiency is lowered. As a result, the exhaust efficiency increases and the fuel consumption rate can be improved.

  Further, in each of the above-described embodiments, the case where a delay occurs in the opening control of the EGR valve 81 as a control delay has been described. The present invention is not limited to this, and can cope with control delays of other actuators. Specifically, when there is a delay in the opening control of the EGR valve 81, the actual in-cylinder state quantity Xr is mainly delayed in adjusting the gas composition in the cylinder. Whereas the delay in adjusting the composition is reflected in the state quantity deviation ΔX, when the fuel injection of the injector 23 is delayed, the actual in-cylinder state quantity Xr is mainly in the cylinder. Therefore, the delay in adjusting the temperature in the cylinder is reflected in the state quantity deviation ΔX.

  Further, in each of the above embodiments, the engine 1 to which the piezo injector 23 that changes the fuel injection rate by being in a fully opened valve state only during the energization period has been described. However, the present invention applies a variable injection rate injector. It can also be applied to the engine.

  In addition, in each of the above-described embodiments, the NSR catalyst 75 and the DPNR catalyst 76 are provided as the manipulator 77, but the NSR catalyst 75 and a DPF (Diesel Particle Filter) may be provided.

  The present invention can be applied to control of the EGR rate and fuel ignition timing in a common rail in-cylinder direct injection multi-cylinder diesel engine mounted on an automobile.

1 engine (internal combustion engine)
23 Injector 47 Accelerator opening sensor 48 Intake pressure sensor 49 Intake temperature sensor 4A In-cylinder pressure sensor 81 EGR valve 100 ECU
Xb In-cylinder state quantity reference value Xr Actual in-cylinder state quantity ΔX State quantity deviation ΔXave State quantity deviation average value ΔXb-ave State quantity change maximum reference value Rt Driver transient (driver's driving transient)

Claims (8)

In a control device for an internal combustion engine that adjusts control parameters according to the degree of operation transient during transient operation of the internal combustion engine,
An in-cylinder state quantity reference value that is information on the in-cylinder state quantity when the steady operation is performed in a state where the control parameters of the internal combustion engine are adapted so that the exhaust emission and the fuel consumption rate both satisfy the required values; From the actual in-cylinder state quantity which is information of the in-cylinder state quantity in the actual operating state of the internal combustion engine, the in-cylinder state quantity in the actual operating state of the internal combustion engine with respect to the in-cylinder state quantity in the above-described adapted steady operation Calculate the state quantity deviation, which is the deviation,
The state quantity deviation average value is calculated by reflecting the current state quantity deviation by smoothing calculation with respect to the average state quantity deviation calculated in the past,
The state quantity deviation in the test mode when the vehicle is driven in the predetermined test mode is obtained in the same manner as the state quantity deviation calculating operation, and this is set as the state quantity change maximum reference value.
According to the ratio of the state quantity deviation average value to the state quantity change maximum reference value or the deviation between the state quantity change maximum reference value and the state quantity deviation average value, the driver's driving transient degree is learned, A control apparatus for an internal combustion engine, characterized in that the control parameter is adjusted in accordance with the learned driving transient degree of the driver. The control apparatus for an internal combustion engine according to claim 1,
A control apparatus for an internal combustion engine, wherein the in-cylinder oxygen concentration as a control parameter is corrected in accordance with the learned driving transient degree of the driver. The control apparatus for an internal combustion engine according to claim 2,
If the ratio of the state variable deviation mean value for the state quantity change maximum reference value is less than "1", or a value obtained by subtracting the state variable changes the maximum reference value from the state variable deviation average value is less than "0" In such a case, the control device for the internal combustion engine is configured such that the smaller the value is, the lower the in-cylinder oxygen concentration as the control parameter is corrected. The control apparatus for an internal combustion engine according to claim 3,
If the ratio of the state variable deviation mean value for the state quantity change maximum reference value is not less than "1", or a value obtained by subtracting the state variable changes the maximum reference value from the state variable deviation average value is "0" or more In this case, the in-cylinder oxygen concentration as the control parameter is maintained at a constant value that satisfies the regulation value even when the value increases. Control device. The control apparatus for an internal combustion engine according to claim 1,
A control device for an internal combustion engine, characterized in that the fuel ignition timing as a control parameter is corrected according to the learned driving transient degree of the driver. The control apparatus for an internal combustion engine according to claim 5,
If the ratio of the state variable deviation mean value for the state quantity change maximum reference value is less than "1", or a value obtained by subtracting the state variable changes the maximum reference value from the state variable deviation average value is less than "0" In such a case, the control apparatus for an internal combustion engine is configured to correct the fuel ignition timing as a control parameter to the advance side as the value is smaller. The control apparatus for an internal combustion engine according to claim 6,
If the ratio of the state variable deviation mean value for the state quantity change maximum reference value is not less than "1", or a value obtained by subtracting the state variable changes the maximum reference value from the state variable deviation average value is "0" or more In this case, the fuel ignition timing as a control parameter is maintained at a constant value that satisfies the regulation value or a constant value that satisfies the required output even if the value increases. A control device for an internal combustion engine. In the control device for an internal combustion engine according to any one of claims 1 to 7,
The control apparatus for an internal combustion engine, wherein the in-cylinder state quantity is at least one of in-cylinder pressure, in-cylinder temperature, and in-cylinder oxygen concentration.

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