JP4914874B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine control device that controls an operation of an internal combustion engine that is provided with an EGR device that causes a portion of burned gas to exist in a cylinder as EGR gas and injects fuel into the cylinder.

  Conventionally, as a control device for this type of internal combustion engine, for example, one disclosed in Patent Document 1 is known. This internal combustion engine is a diesel engine (hereinafter simply referred to as “engine”), and this engine is provided with an external EGR device for recirculating a part of the exhaust gas to the intake pipe as EGR gas. The apparatus has an EGR control valve for controlling the amount of EGR gas (hereinafter simply referred to as “EGR gas amount”). In this conventional control device, the fuel injection amount, fuel injection timing, and EGR gas amount in the engine are controlled as follows. First, first, second and third combustion pressure characteristic values are calculated according to the operating state of the engine. The first combustion pressure characteristic value has a close correlation with the actual fuel injection amount in the engine, and the second combustion pressure characteristic value has a close correlation with the actual end timing of fuel combustion in the cylinder. The third combustion pressure characteristic value has a close correlation with the actual EGR rate (the ratio of the amount of EGR gas to the gas sucked into the cylinder).

  Next, the target value of the first to third combustion pressure characteristic values is calculated by searching a predetermined map determined in accordance with the operating state of the engine. These target values are set so as to obtain an optimal combustion state of the engine. Then, the fuel injection amount is controlled so that the actual value of the first combustion pressure characteristic value becomes the target value, and the fuel injection timing is controlled so that the actual value of the second combustion pressure characteristic value becomes the target value. . Further, the opening degree of the EGR control valve is controlled so that the actual value of the third combustion pressure characteristic value becomes the target value, and the EGR gas amount is controlled. As described above, in this conventional control device, an optimum combustion state is obtained in the internal combustion engine.

  In general, since the external EGR gas device recirculates a part of the exhaust gas to the intake pipe, even if the opening of the EGR control valve is changed, the EGR gas amount does not change immediately but changes with a delay. Further, during transient operation in which the engine load changes abruptly, the amount of EGR gas that can achieve the optimum combustion state of the engine also changes abruptly. On the other hand, the above-described conventional control device only controls the opening degree of the EGR control valve according to the target value of the third combustion pressure characteristic value calculated by searching a predetermined map. Sometimes, the EGR gas amount cannot be properly controlled. In this case, the combustion state of the fuel in the cylinder becomes unstable, leading to excessive combustion noise in the engine and deterioration of fuel consumption and exhaust gas characteristics.

  The present invention has been made in order to solve the above-described problems, and controls an internal combustion engine that can suppress combustion noise and obtain good fuel consumption and exhaust gas characteristics during transient operation of the internal combustion engine. An object is to provide an apparatus.

JP 2005-248703 A

  In order to achieve the above object, the invention according to claim 1 is directed to an internal combustion engine provided with an EGR device 14 that causes a part of burned gas to exist in the cylinder 3b as EGR gas, and injects fuel into the cylinder 3b. 3, a control device 1 for an internal combustion engine that controls the operation of the internal combustion engine 3, and an operation state detection unit that detects an operation state of the internal combustion engine 3 (hereinafter, the same applies to this section), a crank angle sensor 32. , Accelerator opening sensor 36, ECU 2, step 41) and the amount of EGR gas (actual EGR gas amount EGRACT) is controlled according to the detected operating state of engine 3 (engine speed NE, required torque PMCMD). EGR gas amount control means (ECU 2, steps 52 and 55 to 57) for performing combustion state parameters indicating the combustion state of fuel in the cylinder 3b (at the time of actual ignition) Combustion state parameter detection means (in-cylinder pressure sensor 31, ECU 2, step 6, step 11) for detecting TFACT and actual ignition delay SFACT, and target combustion that becomes the target of the combustion state parameter according to the operating state of the internal combustion engine 3 Target combustion state parameter setting means (ECU 2, step 71, step 12) for setting state parameters (target ignition timing TFCMD, target ignition delay SFCMD), and transient operation for determining whether the internal combustion engine 3 is in a transient operation state When it is determined that the determination means (ECU 2, FIG. 6) and the internal combustion engine 3 are in the transient operation state, the target combustion is based on the comparison result (ignition delay deviation DSF) between the target combustion state parameter and the combustion state parameter. By correcting the state parameter, the corrected target combustion state parameter (corrected target ignition timing) When it is determined that the corrected target combustion state parameter calculating means (ECU 2, step 76) for calculating (TFCMD) and the internal combustion engine 3 are in the transient operation state, the combustion state parameter becomes the corrected target combustion state parameter. Thus, the fuel injection timing correction means (ECU2, steps 77 to 79) for correcting the fuel injection timing (target main injection timing TMICMD) into the cylinder 3b is provided.

  According to this control device for an internal combustion engine, the amount of EGR gas (hereinafter simply referred to as “EGR gas amount”) is controlled by the EGR gas amount control means in accordance with the detected operating state of the internal combustion engine. Thereby, the amount of EGR gas can be controlled to an appropriate amount according to the operating state of the internal combustion engine.

  A combustion state parameter representing the combustion state of the fuel in the cylinder is detected by the combustion state parameter detection means, and the target combustion state parameter, which is a target value of the combustion state parameter, is detected in the detected operating state of the internal combustion engine. Accordingly, it is set by the target combustion state parameter setting means. Further, whether or not the internal combustion engine is in the transient operation state is determined by the transient operation determination means, and when it is determined that the internal combustion engine is in the transient operation state, the corrected target combustion state parameter calculation means calculates the target combustion. The corrected target combustion state parameter is calculated by correcting the target combustion state parameter based on the comparison result between the state parameter and the combustion state parameter. Further, when it is determined that the internal combustion engine is in the transient operation state, the fuel injection timing into the cylinder (hereinafter referred to as “fuel injection timing”) so that the combustion state parameter becomes the corrected target combustion state parameter. Is corrected by the fuel injection timing correction means.

  During the transient operation, if the combustion state of the fuel in the cylinder fluctuates due to a delay in response of the EGR gas amount, the difference between the combustion state parameter and the target combustion state parameter representing an appropriate combustion state increases. For this reason, during the transient operation, the comparison result between the target combustion state parameter and the combustion state parameter favorably represents the degree of response delay of the EGR gas amount. Therefore, according to the present invention, it is possible to calculate the corrected target combustion state parameter obtained by correcting the target combustion state parameter with the correction amount corresponding to the response delay of the EGR gas amount during the transient operation of the internal combustion engine. Further, since the fuel injection timing has a response characteristic higher than the EGR gas amount, it can be controlled without a large response delay even during transient operation. Therefore, by controlling the fuel injection timing described above based on the corrected target combustion state parameter as described above, the influence on the combustion state due to the response delay of the EGR gas amount can be compensated for, and the proper combustion of the fuel in the cylinder The state can be obtained. As a result, during the transient operation of the internal combustion engine, combustion noise can be suppressed, and good fuel consumption and exhaust gas characteristics can be obtained.

  According to a second aspect of the present invention, in the control device 1 for an internal combustion engine according to the first aspect, the combustion state parameters include an ignition timing (actual ignition timing TFACT) of the fuel supplied into the cylinder 3b, and into the cylinder 3b. It includes at least one of an ignition delay period (actual ignition delay SFACT) from the fuel injection timing to the ignition timing, and a pressure change rate in the cylinder 3b.

  According to this configuration, the combustion state parameters representing the combustion state of the fuel in the cylinder include the ignition timing of the fuel supplied into the cylinder, the ignition delay period from the fuel injection timing to the ignition timing, and the pressure in the cylinder. At least one of the rate of change is used. All of these parameters have a close correlation with the combustion state of the fuel in the cylinder, so that it is possible to appropriately correct the fuel injection timing in accordance with the combustion state parameter. Sound can be reliably suppressed, and good fuel consumption and exhaust gas characteristics can be reliably obtained.

  According to a third aspect of the present invention, in the control apparatus 1 for an internal combustion engine according to the first or second aspect, a deviation degree parameter (ignition delay deviation DSF) representing a deviation degree between the target combustion state parameter and the combustion state parameter is calculated. Deviation degree parameter calculation means (ECU2, step 13) and learning means for calculating a learning value (learned value GDSF) of the deviation degree parameter based on a plurality of deviation degree parameters calculated so far by the deviation degree parameter calculation means. (ECU2, Steps 24-26), and the EGR gas amount control means controls the amount of EGR gas according to the calculated learning value of the deviation degree parameter (Steps 54-57). Features.

  According to this configuration, the deviation degree parameter indicating the deviation degree between the target combustion state parameter and the combustion state parameter is calculated by the deviation degree parameter calculating means, and the learning value of the deviation degree parameter has been calculated up to this time. It is calculated by the learning means based on a plurality of deviation degree parameters. Further, the EGR gas amount is further controlled according to the calculated learning value of the deviation degree parameter. By controlling the amount of EGR gas according to the operation state of the internal combustion engine described in the operation of claim 1, an appropriate combustion state is obtained depending on the influence of changes in environmental factors such as the properties of the fuel, the operating characteristics of the EGR device, and humidity. In some cases, there is a gap between the target combustion state parameter and the combustion state parameter. Even in such a case, according to the present invention, it is possible to compensate for the influence due to the change in the properties of the fuel by controlling the EGR gas amount further in accordance with the above-described divergence degree parameter. Thus, an appropriate combustion state can be obtained, so that combustion noise can be suppressed and good fuel consumption and exhaust gas characteristics can be obtained.

  In this case, since the learning value calculated based on the plurality of divergence degree parameters calculated so far is used for controlling the EGR gas amount, it is included in the combustion state parameter detected by the combustion state parameter detecting means. Even when the combustion state parameter temporarily changes due to possible noise or actual combustion state fluctuation, it is possible to appropriately control the EGR gas amount while suppressing the influence thereof.

  According to a fourth aspect of the present invention, in the internal combustion engine control apparatus 1 according to the third aspect, in the internal combustion engine 3, pilot injection and main injection are sequentially performed as fuel injection into the cylinder 3b. The timing correction means corrects the timing of the main injection (target main injection timing TMICMD), and controls at least one of the pilot injection timing and the fuel amount by pilot injection according to the learned value of the deviation degree parameter. (ECU2, steps 63, 64, 66, and 67).

  According to this configuration, at least one of the pilot injection timing (hereinafter referred to as “pilot injection timing”) and the fuel amount by pilot injection (hereinafter referred to as “pilot injection amount”) depends on the learned value of the deviation degree parameter. It is controlled by the control means. For this reason, even when an appropriate combustion state cannot be obtained due to the influence of changes in the properties of the fuel, the properties of the fuel are controlled by controlling the pilot injection timing and / or pilot injection amount in accordance with the above-described combustion state parameters. It is possible to more appropriately compensate for the influence due to the change in. As a result, an appropriate combustion state as represented by the target combustion state parameter can be reliably obtained, so that combustion noise can be reliably suppressed and good fuel consumption and exhaust gas characteristics can be reliably obtained. Further, also in the control of the pilot injection timing and the pilot injection amount, the learned value of the divergence degree parameter is used similarly to the control of the EGR gas amount of claim 3, so even when the combustion state parameter fluctuates temporarily, It is possible to appropriately control the pilot injection timing and the pilot injection amount while suppressing the influence caused thereby.

  According to a fifth aspect of the present invention, in the control device 1 for an internal combustion engine according to the third or fourth aspect, the learning means determines that the internal combustion engine 3 is determined to be in a transient operation state and the previous deviation. When at least one of the conditions that the predetermined period (predetermined time TREF) has not elapsed since the calculation of the learning value of the degree parameter is satisfied (step 21: YES, step 22: NO), the learning value of the deviation degree parameter It is characterized by prohibiting the calculation of.

  According to this configuration, calculation of the learned value of the deviation degree parameter is prohibited during transient operation of the internal combustion engine and / or when a predetermined period has not elapsed since the previous calculation of the learned value of the deviation degree parameter. . During the transient operation of the internal combustion engine, since the operation state of the internal combustion engine changes abruptly, the combustion state changes more greatly than in other cases, so the divergence degree parameter during such transient operation is The degree of influence due to changes in environmental factors such as the properties of the fuel, the operating characteristics of the EGR device, and humidity is not well represented. Therefore, by avoiding the calculation of the learning value of the deviation degree parameter as described above during such transient operation, the control of the amount of EGR gas according to the learning value causes the change in the properties of the fuel. The influence can be compensated more appropriately. As a result, the combustion noise can be more reliably suppressed, and good fuel consumption and exhaust gas characteristics can be more reliably obtained.

  In addition, since the operating characteristics of the EGR device do not change immediately, it is sufficient to calculate the learning value of the deviation degree parameter after a certain period of time in order to compensate for the influence on the combustion state. It is. Therefore, as described above, the learning value of the deviation degree parameter is calculated on the condition that a predetermined period has passed since the previous calculation, thereby appropriately compensating for the influence due to the change in the operation characteristics of the EGR device. However, the calculation load of the control device can be reduced.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 2 schematically shows a control device 1 for an internal combustion engine according to the first embodiment of the present invention. As shown in FIG. 2, the control device 1 includes an ECU 2 and various sensors described later.

  FIG. 1 schematically shows an internal combustion engine 3 to which the control device 1 is applied. This internal combustion engine (hereinafter referred to as “engine”) 3 is a diesel engine mounted as a drive source in a vehicle (not shown). It is an engine. As shown in FIG. 1, an intake pipe 4 and an exhaust pipe 5 are connected to a cylinder head 3a of the engine 3, and a fuel injection valve (hereinafter referred to as "injector") 6 faces a piston 3c in the cylinder 3b. It is attached as follows.

  The injector 6 is sequentially connected to a high-pressure pump and a fuel tank (both not shown) via a common rail. The high-pressure pump boosts the fuel in the fuel tank to a high pressure, and then sends the fuel to the injector 6 via the common rail. The injector 6 injects the fuel into the cylinder 3b. In the engine 3, as the fuel injection, both pilot injection for injecting fuel during an arbitrary period from the intake stroke to the compression stroke of the engine 3 and main injection for injecting fuel during the compression stroke are executed. The fuel injection amount and fuel injection timing for pilot injection and main injection are controlled by the ECU 2. Hereinafter, the fuel injection timing and the fuel injection amount for pilot injection are referred to as “pilot injection timing” and “pilot injection amount”, respectively, and the fuel injection timing for main injection is referred to as “main injection timing”. In the present embodiment, the pilot injection timing and the main injection timing are defined as the end timings of the pilot injection and the main injection, respectively.

  An in-cylinder pressure sensor 31 is integrally attached to the injector 6. The in-cylinder pressure sensor 31 is configured by a ring-shaped piezoelectric element, and outputs a detection signal representing a change amount of pressure in the cylinder 3b (hereinafter referred to as “in-cylinder pressure change amount”) DPV to the ECU 2. The ECU 2 calculates the pressure in the cylinder 3b (hereinafter referred to as “in-cylinder pressure”) based on the in-cylinder pressure change amount DPV as described later.

  Further, a magnet rotor 32a is attached to the crankshaft 3d of the engine 3, and a crank angle sensor 32 is constituted by the magnet rotor 32a and the MRE pickup 32b. The crank angle sensor 32 outputs a CRK signal and a TDC signal, which are pulse signals, to the ECU 2 as the crankshaft 3d rotates. The CRK signal is output every predetermined crank angle (for example, 1 °). The ECU 2 obtains the engine speed (hereinafter referred to as “engine speed”) NE of the engine 3 based on the CRK signal. The TDC signal is a signal indicating that the piston 3c is at a predetermined crank angle position near the TDC (top dead center) at the start of the intake stroke.

  Further, the intake pipe 4 is provided with a supercharging device 7, which is a supercharger 8 constituted by a turbocharger, an actuator 9 connected thereto, and a vane opening control valve. 10 is provided.

  The supercharger 8 includes a rotatable compressor blade 8a provided in the intake pipe 4, a rotatable turbine blade 8b provided in the exhaust pipe 5, and a plurality of rotatable variable vanes 8c (only two are shown). And a shaft 8d for integrally connecting these blades 8a and 8b. The turbocharger 8 pressurizes the intake air in the intake pipe 4 by rotationally driving the compressor blade 8a integrated therewith as the turbine blade 8b is rotationally driven by the exhaust gas in the exhaust pipe 5. Perform supercharging operation.

  The actuator 9 is of a diaphragm type that is operated by negative pressure, and is mechanically connected to each variable vane 8c. A negative pressure is supplied to the actuator 9 from a negative pressure pump via a negative pressure supply passage (both not shown), and a vane opening degree control valve 10 is provided in the middle of the negative pressure supply passage. The vane opening control valve 10 is composed of an electromagnetic valve, and the negative pressure supplied to the actuator 9 changes when the opening is controlled by a drive signal from the ECU 2, and accordingly, the variable vane 8c The supercharging pressure is controlled by changing the opening degree.

  Further, a water-cooled intercooler 11 and a throttle valve 12 are provided on the intake pipe 4 downstream of the supercharger 8 in order from the upstream side. The intercooler 11 cools the intake air when the temperature of the intake air rises due to the supercharging operation of the supercharging device 7. The throttle valve 12 is connected to an actuator 12a made of, for example, a DC motor. The opening degree of the throttle valve 12 is controlled by the ECU 2 by controlling the duty ratio of the current supplied to the actuator 12a. Be controlled.

  Further, a supercharging pressure sensor 33 is provided between the intercooler 11 and the throttle valve 12 in the intake pipe 4. The supercharging pressure sensor 33 detects a supercharging pressure PACT in the intake pipe 4 and outputs a detection signal to the ECU 2.

  Further, the engine 3 is provided with an EGR device 14 having an EGR pipe 14a and an EGR control valve 14b. The EGR pipe 14 a is connected between the intake pipe 4 and the exhaust pipe 5, specifically, the downstream side of the intake pipe 4 from the throttle valve 12 and the upstream side of the supercharger 8 of the exhaust pipe 5. It is connected. A part of the exhaust gas of the engine 3 is recirculated as EGR gas to the intake pipe 4 through the EGR pipe 14a, thereby reducing the combustion temperature in the cylinder 3b, thereby reducing NOx in the exhaust gas.

  The EGR control valve 14b is composed of a linear electromagnetic valve attached to the EGR pipe 14a, and the amount of EGR gas (hereinafter referred to as the EGR gas amount) is controlled linearly by a drive signal from the ECU 2. Simply referred to as “EGR gas amount”). The valve lift amount LACT of the EGR control valve 14b is detected by the valve lift amount sensor 34, and the detection signal is output to the ECU 2.

  The EGR device 14 is provided with an EGR cooling device 15 for cooling the EGR gas. The EGR cooling device 15 includes a bypass passage 15a, an EGR passage switching valve 15b, and an EGR control valve for the EGR pipe 14a. It has an EGR cooler 15c provided downstream of 14b. The bypass passage 15a is provided downstream of the EGR control valve 14b of the EGR pipe 14a so as to bypass the EGR cooler 15c, and the EGR passage switching valve 15b is attached to a branch portion of the bypass passage 15a. ing. The EGR passage switching valve 15b selectively switches a portion of the EGR pipe 14a downstream of the EGR passage switching valve 15b to the EGR pipe 14a side and the bypass passage 15a side under the control of the ECU 2.

  As described above, when the EGR passage switching valve 15b is switched to the bypass passage 15a side, the EGR gas is passed through the bypass passage 15a and recirculates to the intake pipe 4. On the other hand, when switched to the reverse side, the EGR gas is cooled by the EGR cooler 15c and then returned to the intake pipe 4.

  The exhaust pipe 5 is provided with an exhaust gas flow rate sensor 35. The exhaust gas flow rate sensor 35 detects an exhaust gas flow rate (hereinafter referred to as "exhaust gas flow rate") QE and outputs a detection signal to the ECU 2. Further, a detection signal representing an operation amount (hereinafter referred to as “accelerator opening”) AP of an accelerator pedal (not shown) is output from the accelerator opening sensor 36 to the ECU 2.

  The ECU 2 is composed of a microcomputer including an I / O interface, CPU, RAM, ROM, and the like. The detection signals from the various sensors 31 to 36 described above are input to the CPU after A / D conversion and shaping by the I / O interface. In accordance with these input signals, the ECU 2 determines the operating state of the engine 3 according to a control program stored in the ROM and the like, and according to the determined operating state, the EGR gas amount, the fuel injection amount, the fuel injection timing The operation of the engine 3 including the control is controlled.

  The outline of the control by the ECU 2 will be described. The ECU 2 calculates various control parameters for controlling the operation of the engine 3 (FIGS. 3 to 5 and FIG. 7), and the calculated various control parameters. The EGR gas amount, the pilot injection, and the main injection timing are controlled according to the parameters (FIGS. 8, 9, and 10). Further, it is determined whether or not the engine 3 is in a transient operation state (FIG. 6), and the main injection timing is controlled further according to the determination result. Hereinafter, various processes performed by the ECU 2 will be described with reference to FIGS.

  FIG. 3 shows control parameter calculation processing for calculating various control parameters. This process is executed in synchronization with the generation of the CRK signal described above. First, in step 1 (illustrated as “S1”, the same applies hereinafter), the in-cylinder pressure Pθ is calculated by integrating the detected in-cylinder pressure change amount DPV. Next, the in-cylinder volume change rate dVθ is calculated based on the CRK signal (step 2). This in-cylinder volume change rate dVθ is a change rate of the volume in the cylinder 3b per a predetermined crank angle (the volume in the cylinder 3b defined by the cylinder head 3a and the piston 3c).

  Next, the in-cylinder volume Vθ is calculated based on the TDC signal and the CRK signal (step 3). This in-cylinder volume Vθ is the volume in the cylinder 3b at that time. Next, in-cylinder pressure change rate dPθ is calculated in accordance with the CRK signal and in-cylinder pressure change amount DPV (step 4). The in-cylinder pressure change rate dPθ is a change rate of the in-cylinder volume Vθ per the predetermined crank angle.

Next, using the in-cylinder pressure Pθ, the in-cylinder volume change rate dVθ, the in-cylinder volume Vθ, and the in-cylinder pressure change rate dPθ calculated in Steps 1 to 4 above, the heat generation rate per predetermined crank angle in the cylinder 3b. dQθ is calculated by the following equation (1) (step 5).
dQθ = (κ · Pθ · 1000 · dVθ + dPθ · 1000 · Vθ)
/ (Κ-1) (1)
Here, κ is a predetermined specific heat ratio, and is set to 1.34, for example.

  Next, an actual ignition timing (hereinafter referred to as “actual ignition timing”) TFACT of the fuel in the cylinder 3b is calculated (step 6). This actual ignition timing TFACT is calculated as follows. That is, the heat generation rate in the cylinder 3b is calculated by integrating the heat generation rate dQθ calculated in step 5 above. Then, according to the TDC signal and CRK signal, the crank angle position when the calculated heat generation amount becomes ½ of the total heat generation amount in one combustion cycle of the engine 3 is determined as the actual ignition timing. Calculated as TFACT.

  Next, the indicated mean effective pressure IMEP in the engine 3 is calculated (step 7), and this process ends. This indicated mean effective pressure IMEP is calculated by the method disclosed by the present applicant in Japanese Patent Laid-Open No. 2006-52647 using the in-cylinder pressure change amount DPV.

  FIG. 4 shows an ignition delay calculation process for calculating an actual ignition delay SFACT and the like. This process is executed in synchronization with the generation of the TDC signal. First, in step 11, an actual ignition delay SFACT is calculated. This actual ignition delay SFACT represents the period from the main injection timing to the above actual ignition timing TFACT (the time required until the fuel by main injection ignites) in terms of the crank angle. It is calculated by subtracting the final main injection timing TMIOUT from TFACT. This final main injection timing TMIOUT is calculated as will be described later, and the main injection timing is controlled by outputting a drive signal based on the final main injection timing TMIOUT to the injector 6. The actual ignition delay SFACT is calculated using the actual ignition timing TFACT and the final main injection timing TMIOUT calculated in the previous combustion cycle. As described above, the actual ignition delay SFACT is calculated as the actual period from the main injection timing to the actual ignition timing TFACT in the previous combustion cycle.

  Next, the target ignition delay SFCMD which is the target value of the actual ignition delay SFACT is calculated by subtracting the target main injection timing TMICMD from the target ignition timing TFCMD (step 12). These target ignition timing TFCMD and target main injection timing TMICMD are target values of actual ignition timing TFACT and main injection timing, respectively, and are calculated as described later. In the present embodiment, the target ignition timing TFCMD and the target main injection timing TMICMD calculated in the previous combustion cycle are used for calculating the target ignition delay SFCMD to correspond to the actual ignition delay SFACT. You may use the TFCMD value and TMICMD value calculated in the combustion cycle.

  Next, the deviation (SFCMD-SFACT) between the target ignition delay SFCMD calculated in step 12 and the actual ignition delay SFACT calculated in step 11 is calculated as an ignition delay deviation DSF (step 13), and this process is terminated. To do.

  FIG. 5 shows a DSF learning process for calculating the learning value GDSF of the ignition delay deviation DSF. This process is executed in synchronization with the generation of the TDC signal. First, in step 21, it is determined whether or not the transient operation flag F_TRA is “1”. This transient operation flag F_TRA is set to “1” when it is determined in the transient operation determination process shown in FIG. 6 that the engine 3 is in the transient operation state. Hereinafter, the transient operation determination process will be described.

  In step 31 of FIG. 6, the torque pressure ratio RTI is calculated by dividing the required torque PMCMD by the indicated mean effective pressure IMEP calculated in step 7 of FIG. The required torque PMCMD is a torque required for the engine 3, and a predetermined map (not shown) is displayed according to the calculated engine speed NE and the detected accelerator pedal opening AP in step 41 of FIG. Calculated by searching. In this map, the required torque PMCMD is set to a larger value as the accelerator pedal opening AP is larger.

  Next, it is determined whether or not the torque pressure ratio RTI calculated in step 31 is smaller than a predetermined upper limit value R_H and larger than a predetermined lower limit value R_L (step 32). These upper limit value R_H and lower limit value R_L are set in advance by experiments or the like so that it can be appropriately determined whether or not the engine 3 is in a transient operation state.

  If the answer to step 32 is YES and R_L <RTI <R_H, it is determined that the engine 3 is not in a transient operation state (in a steady operation state), and the transient operation flag F_TRA is set to “ “0” is set (step 33), and this process is terminated.

  On the other hand, when the answer to step 32 is NO, it is determined that the engine 3 is in a transient operation state, and the transient operation flag F_TRA is set to “1” to indicate that (step 34), and this process is performed. finish.

  Returning to FIG. 5, when the answer to step 21 is YES and F_TRA = 1, that is, when the engine 3 is in a transient operation state, this process is terminated without calculating the learning value GDSF. On the other hand, if the answer to step 21 is NO and the engine 3 is not in the transient operation state, it is determined whether or not a predetermined time TREF has elapsed since the previous calculation of the learning value GDSF (step 22).

If the answer to step 22 is NO, and the predetermined time TREF has not elapsed since the previous calculation of the learning value GDSF, the processing is terminated without calculating the learning value GDSF. On the other hand, when the answer to step 22 is YES, it is determined whether or not a predetermined condition, that is, both of the following two conditions (a) and (b) are satisfied (step 23).
(A) The deviation between the target EGR gas amount EGRCMD and the actual EGR gas amount EGRACT is approximately 0 (b) The deviation between the target boost pressure and the detected boost pressure PACT is approximately 0 The target EGR gas amount EGRCMD is a target value of the EGR gas amount, and is calculated as described later. The actual EGR gas amount EGRACT is a calculated value of the actual EGR gas amount and is calculated as described later. Further, the target supercharging pressure is a target value of the supercharging pressure PACT, and is calculated by searching a predetermined map (not shown) according to the engine speed NE and the required torque PMCMD.

If the answer to step 23 is NO and the above-described predetermined condition is not satisfied, the process ends without calculating the learning value GDSF. On the other hand, when all the answers to steps 21 to 23 are YES, it is considered that the execution condition for calculating the learning value GDSF is satisfied. Then, the learning value GDSF corresponding to the engine speed NE and the required torque PMCMD at that time is read from the RAM of the ECU 2 storing the learning value GDSF, and set as the previous value GDSFZ (step 24). Next, using the previous value GDSFZ set in step 24 and the ignition delay deviation DSF calculated in step 13 of FIG. 4, the current learning value GDSF is calculated by the following equation (2) (step 25).
GDSF = GDSFZ + (DSF−GDSFZ) · K (2)
Here, K is a predetermined coefficient larger than 0.

  Next, the learning value GDSF calculated in the above step 25 is stored in the RAM of the ECU 2 in correspondence with the engine speed NE and the required torque PMCMD at that time (step 26) and updated, and this process is terminated. .

  FIG. 8 shows an EGR control process for controlling the EGR gas amount. This process is executed every predetermined time (for example, 10 msec). First, in step 51, the above-described actual EGR gas amount EGRACT is calculated by searching a predetermined EGRACT map (not shown) according to the detected valve lift amount LACT and exhaust gas flow rate QE. This EGRACT map is a map obtained by previously obtaining the relationship between the valve lift amount LACT, the exhaust gas flow rate QE, and the EGR gas amount by experiments or the like.

  Next, the aforementioned target EGR gas amount EGRCMD is calculated by searching a predetermined EGRCMD map (not shown) according to the engine speed NE and the required torque PMCMD (step 52). In this EGRCMD map, the target EGR gas amount EGRCMD is set in advance by experiments or the like so as to obtain an appropriate combustion state.

  Next, the learning value GDSF corresponding to the engine speed NE and the required torque PMCMD at that time is read from the RAM of the ECU 2 (step 53). Next, a correction value CEGR is calculated by searching a predetermined CEGR map (not shown) according to the learning value GDSF read in step 53 (step 54). The CEGR map will be described later. Next, the corrected target EGR gas amount CEGRCMD is calculated by adding the correction value CEGR calculated in step 54 to the target EGR gas amount EGRCMD calculated in step 52 (step 55).

  Next, a deviation (CEGRCMD-EGRACT) between the corrected target EGR gas amount CEGRCMD and the actual EGR gas amount EGRACT calculated in step 51 is calculated as an EGR deviation DEGR (step 56). Next, the final EGR gas amount EGROUT is calculated by a predetermined feedback control algorithm in accordance with the EGR deviation DEGR calculated in step 56 (step 57), and this process is terminated. Accordingly, a drive signal based on the final EGR gas amount EGROUT is output to the EGR control valve 14b. As described above, the EGR gas amount is feedback-controlled so as to become the corrected target EGR gas amount CEGRCMD.

  The CEGR map includes a first CEGR map and a second CEGR map (both not shown). The first CEGR map is used when the learning value GDSF is a positive value, that is, when the actual ignition delay SFACT is shorter (periodically shorter) than the target ignition delay SFCMD, and the second CEGR map is the learning value GDSF. Is a negative value, that is, when the actual ignition delay SFACT is longer (longer in terms of time) than the target ignition delay SFCMD. In the first CEGR map, the correction value CEGR is set to a larger value as the learning value GDSF is larger. This is because, as the learning value GDSF is larger, that is, as the actual ignition delay SFACT is shorter than the target ignition delay SFCMD, the combustion speed of the fuel in the cylinder 3b becomes too high and the combustion state is not appropriate, so the target EGR gas By increasing the amount of EGRCMD by increasing the amount of EGRCMD, the combustion speed is lowered and the combustion is slowed down, thereby obtaining an appropriate combustion state.

  In the second CEGR map, the correction value CEGR is set to a smaller value as the absolute value of the negative learning value GDSF is larger. This is because, as the absolute value of the learning value GDSF is larger, that is, the actual ignition delay SFACT is longer than the target ignition delay SFCMD, the fuel combustion speed becomes too low and the combustion state is not appropriate, so the target EGR gas amount This is because the combustion rate is increased by reducing the amount of EGR gas by reducing EGRCMD, thereby obtaining an appropriate combustion state.

  FIG. 9 shows a pilot injection control process for controlling the pilot injection amount and the pilot injection timing described above. This process is executed in synchronization with the generation of the TDC signal. First, in step 61, a target pilot injection amount QPICMD, which is a target value of the pilot injection amount, is calculated by searching a predetermined QPICMD map (not shown) according to the engine speed NE and the required torque PMCMD. In this QPICCMD map, the target pilot injection amount QPICMD is set in advance by experiments or the like so as to appropriately increase the temperature in the cylinder 3b and thereby obtain an appropriate combustion state of fuel by main injection.

  Next, the learning value GDSF corresponding to the engine speed NE and the required torque PMCMD at that time is read from the RAM of the ECU 2 (step 62). Next, a correction value CQPI is calculated by searching a predetermined CQPI map (not shown) according to the learning value GDSF read in step 62 (step 63). This CQPI map will be described later. Next, the final pilot injection amount QPIOUT is calculated by adding the correction value CQPI calculated in step 63 to the target pilot injection amount QPICCMD calculated in step 61 (step 64). Accordingly, a drive signal based on the final pilot injection amount QPIOUT is output to the injector 6 so that the pilot injection amount is controlled to be the final pilot injection amount QPIOUT.

  The CQPI map is composed of a first CQPI map and a second CQPI map (both not shown). This first CQPI map is used when the learning value GDSF is positive, that is, when the actual ignition delay SFACT is shorter than the target ignition delay SFCMD, and the second CQPI map is when the learning value GDSF is negative. That is, it is used when the actual ignition delay SFACT is longer than the target ignition delay SFCMD. In the first CQPI map, the correction value CQPI is set to a smaller value as the learning value GDSF is larger. This is because as the learned value GDSF is larger, that is, the actual ignition delay SFACT is shorter than the target ignition delay SFCMD, the fuel combustion speed becomes too high and the combustion state is not appropriate, so the target pilot injection amount QPICMD decreases. This is because by reducing the pilot injection amount by the correction, the temperature in the cylinder 3b is lowered to lower the combustion speed, thereby obtaining an appropriate combustion state.

  In the second CQPI map, the correction value CQPI is set to a larger value as the absolute value of the learning value GDSF, which is a negative value, is larger. This is because, as the absolute value of the learning value GDSF is larger, that is, the actual ignition delay SFACT is longer than the target ignition delay SFCMD, the fuel combustion speed becomes too low and the combustion state is not appropriate. This is because by increasing the pilot injection amount by increasing the correction of QPICMD, the temperature in the cylinder 3b is increased to increase the combustion speed, thereby obtaining an appropriate combustion state.

  Next, a target pilot injection timing TPICMD, which is a target value of the pilot injection timing, is calculated by searching a predetermined TPICMD map (not shown) according to the engine speed NE and the required torque PMCMD (step 65). In this TPICMD map, the target pilot injection timing TPICMD is such that the temperature in the cylinder 3b is appropriately increased by favorably burning the fuel by the pilot injection, so that the proper combustion state of the fuel by the main injection can be obtained. In addition, it is set in advance by experiments or the like.

  Next, a correction value CTPI is calculated by searching a predetermined CTPI map (not shown) according to the learning value GDSF read in step 62 (step 66). This CTPI map will be described later. Next, the final pilot injection timing TPIOUT is calculated by adding the correction value CTPI to the target pilot injection timing TPICMD calculated in step 65 (step 67), and this process is terminated. Accordingly, a drive signal based on the final pilot injection timing TPIOUT is output to the injector 6 so that the pilot injection timing is controlled to be the final pilot injection timing TPIOUT.

  The CTPI map includes a first CTPI map and a second CTPI map (both not shown). This first CTPI map is used when the learning value GDSF is a positive value, that is, when the actual ignition delay SFACT is shorter than the target ignition delay SFCMD, and the second CTPI map is when the learning value GDSF is a negative value, That is, it is used when the actual ignition delay SFACT is longer than the target ignition delay SFCMD. In the first CTPI map, the correction value CTPI is set so that the target pilot injection timing TPICMD is corrected more retarded as the learning value GDSF is larger. This is because as the learned value GDSF is larger, that is, as the actual ignition delay SFACT is shorter than the target ignition delay SFCMD, the fuel combustion speed becomes too high and the combustion state is not appropriate. This is because the fuel in the pilot injection is not burned all at once by controlling the injection timing, thereby lowering the temperature in the cylinder 3b, thereby lowering the combustion speed and thereby obtaining an appropriate combustion state.

  Further, in the second CTPI map, the correction value CTPI is set so as to correct the target pilot injection timing TPICMD to the advance side as the absolute value of the negative learning value GDSF increases. This is because the greater the absolute value of the learning value GDSF, that is, the longer the actual ignition delay SFACT is than the target ignition delay SFCMD, the fuel combustion speed becomes too low and the combustion state is not appropriate. By controlling the pilot injection timing, the fuel in the pilot injection is burned all at once by premixed combustion, and the temperature in the cylinder 3b is increased to increase the combustion speed, thereby achieving an appropriate combustion state. To get.

  FIG. 10 shows a main injection timing control process for controlling the main injection timing described above. This process is executed in synchronization with the generation of the TDC signal. First, in step 71, the above-described target ignition timing TFCMD is calculated by searching a predetermined map (not shown) according to the engine speed NE and the required torque PMCMD. In this map, the target ignition timing TFCMD is set in advance by experiments or the like so that an appropriate combustion state can be obtained.

  Next, the above-described target main injection timing TMICMD is calculated by searching a predetermined TMICMD map (not shown) according to the engine speed NE and the required torque PMCMD (step 72). In this TMICCMD map, the target main injection timing TMICMD is set in correspondence with the above-described target ignition timing TFCMD, and is set in advance by experiments or the like so that the actual ignition timing TFACT becomes the target ignition timing TFCMD.

  Next, it is determined whether or not the transient operation flag F_TRA set in step 33 or 34 of FIG. 6 is “1” (step 73). If the answer is NO and the engine 3 is not in the transient operation state, the difference between the target ignition timing TFCMD calculated in step 71 and the actual ignition timing TFACT calculated in step 6 of FIG. 3 (TFCMD−TFACT). ) Is calculated as the ignition timing deviation DTF (step 74).

  On the other hand, if the answer to step 73 is YES and the engine 3 is in a transient operation state, a predetermined CTF map (not shown) is searched according to the ignition delay deviation DSF calculated in step 13 of FIG. Thus, the correction value CTF is calculated (step 75). This CTF map will be described later. Next, the corrected target ignition timing CTFCMD is calculated by adding the correction value CTF calculated in step 75 to the target ignition timing TFCMD calculated in step 71 (step 76). Next, a deviation (CTFCMD−TFACT) between the corrected target ignition timing CTFCMD calculated in step 76 and the actual ignition timing TFACT is calculated as an ignition timing deviation DTF (step 77).

  In step 78 following step 74 or 77, the F / B correction value CMI is calculated by a predetermined feedback control algorithm based on the calculated ignition timing deviation DTF (step 78). Next, the final main injection timing TMIOUT is calculated by adding the F / B correction value CMI calculated in step 78 to the target main injection timing TMICMD calculated in step 72 (step 79). Exit. Along with this, a drive signal based on the final main injection timing TMIOUT is output to the injector 6. Thereby, by controlling the main injection timing, the actual ignition timing TFACT becomes the target ignition timing TFCMD when the engine 3 is not in a transient operation, and the corrected target ignition timing CTFCMD during the transient operation. Each is feedback controlled.

  Further, the CTF map used during the transient operation of the engine 3 includes a first CTF map and a second CTF map (both not shown). This first CTF map is used when the ignition delay deviation DSF is a positive value, that is, when the actual ignition delay SFACT is shorter than the target ignition delay SFCMD, and the second CTF map described above has a negative ignition delay deviation DSF. This is used when the actual ignition delay SFACT is longer than the target ignition delay SFCMD. In the first CTF map, the correction value CTF is set so as to correct the target ignition timing TFCMD to the retard side as the ignition delay deviation DSF increases. This is due to the following reason. The fact that the ignition delay deviation DSF is large, that is, the actual ignition delay SFACT is shorter than the target ignition delay SFCMD, the fuel is burned in the cylinder 3b due to a shortage of the EGR gas amount due to the response delay accompanying transient operation. This means that it is easy to do. In such a situation, if the target ignition timing TFCMD set in the search of the TFCMD map as described above is used as it is, the actual ignition timing TFACT becomes too early, so that an appropriate combustion state cannot be obtained. For this reason, by correcting the target ignition timing TFCMD to the more retarded angle side and appropriately delaying the actual ignition timing TFACT, an appropriate combustion state is obtained.

  In the second CTF map, the correction value CTF is set so that the target ignition timing TFCMD is corrected to the more advanced side as the absolute value of the ignition delay deviation DSF, which is a negative value, is larger. This is due to the following reason. The fact that the absolute value of the ignition delay deviation DSF is large, that is, that the actual ignition delay SFACT is longer than the target ignition delay SFCMD, the fuel is burned because the EGR gas amount becomes excessive due to the response delay accompanying transient operation. This indicates that the situation is difficult to do. In such a situation, if the target ignition timing TFCMD is used as it is, the actual ignition timing TFACT becomes too late, so that an appropriate combustion state cannot be obtained. For this reason, by correcting the target ignition timing TFCMD to the more advanced side, the actual ignition timing TFACT is appropriately advanced to obtain an appropriate combustion state.

  The correspondence between various elements in the present embodiment and various elements of the present invention is as follows. That is, the ECU 2 operates the operating state detecting means, the EGR gas amount controlling means, the combustion state parameter detecting means, the target combustion state parameter setting means, the transient operation determining means, the corrected target combustion state parameter calculating means, the fuel injection timing correcting means, the deviation It corresponds to degree parameter calculation means, learning means, and pilot injection control means. Further, the in-cylinder pressure sensor 31 corresponds to the combustion state parameter detection means, and the crank angle sensor 32 and the accelerator opening sensor 36 correspond to the operation state detection means.

  Furthermore, the actual EGR gas amount EGRACT corresponds to the amount of EGR gas in the operating state of the internal combustion engine in which the engine speed NE and the required torque PMCMD are detected. Further, the actual ignition timing TFACT corresponds to the combustion state parameter and the ignition timing, the target ignition timing TFCMD corresponds to the target combustion state parameter, and the actual ignition delay SFACT corresponds to the combustion state parameter and the ignition delay period, respectively. Further, the target ignition delay SFCMD corresponds to the target combustion state parameter, the ignition delay deviation DSF corresponds to the comparison result and the deviation degree parameter with the combustion state parameter, and the corrected target ignition timing CTFCMD corresponds to the corrected target combustion state parameter. Further, the target main injection timing TMICMD corresponds to the fuel injection timing into the cylinder and the main injection timing, the learning value GDSF corresponds to the learning value of the deviation degree parameter, and the predetermined time TREF corresponds to the predetermined period.

  As described above, according to the present embodiment, the EGR gas amount is controlled according to the target EGR gas amount EGRCMD calculated using the engine speed NE and the required torque PMCMD (steps 52 and 55-57). ). Thereby, the amount of EGR gas can be controlled to an appropriate size according to the operating state of the engine 3. Further, during the transient operation of the engine 3, the corrected target ignition timing CTFCMD is calculated by correcting the target ignition timing TFCMD based on the ignition delay deviation DSF (steps 75 and 76). Further, during transient operation, the target main injection timing TMICMD is corrected by the F / B correction value CMI calculated so that the actual ignition timing TFACT becomes the corrected target ignition timing CTFCMD, and the final main injection timing TMIOUT calculated thereby is corrected. Based on this, the main injection timing is controlled (steps 77 to 79).

  Further, in the correction of the target ignition timing TFCMD based on the above-described ignition delay deviation DSF, the target ignition becomes shorter as the actual ignition delay SFACT is shorter than the target ignition delay SFCMD, that is, as the fuel is more easily burned due to the response delay of the EGR gas amount. The timing TFCMD is corrected to the more retarded side. In addition, the target ignition timing TFCMD is corrected to the more advanced side as the actual ignition delay SFACT is longer than the target ignition delay SFCMD, that is, the more difficult the fuel is combusted due to the response delay of the EGR gas amount. As described above, the influence on the combustion state due to the response delay of the EGR gas amount can be compensated, and the proper combustion state of the fuel in the cylinder 3b can be obtained. As a result, combustion noise can be suppressed during the transient operation of the engine 3, and good fuel consumption and exhaust gas characteristics can be obtained. Further, since the actual ignition timing TFACT having a close correlation with the combustion state of the fuel in the cylinder 3b is used for the control of the main injection timing as described above, the combustion noise can be reliably suppressed during the transient operation, Good fuel consumption and exhaust gas characteristics can be obtained with certainty.

  Further, the EGR gas amount is controlled further according to the learning value GDSF of the ignition delay deviation DSF (steps 54 to 57). As a result, an appropriate combustion state cannot be obtained due to the influence of changes in environmental factors such as fuel properties, operation (output) characteristics of the EGR device 14, EGR cooler 15c, intercooler 11, and various sensors, and humidity. Even in this case, this influence can be compensated, and thereby an appropriate combustion state as represented by the target ignition delay SFCMD can be obtained, so that combustion noise can be suppressed and good fuel consumption and exhaust gas characteristics can be obtained. . In particular, when the calculation of the actual EGR gas amount EGRACT used for controlling the EGR gas amount is performed according to the intake air amount detected by the air flow sensor provided in the intake pipe 4, such an air flow sensor is used. The output characteristics are particularly easy to change, and the influence on the combustion state becomes remarkable. In such a case, by controlling the amount of EGR gas according to the learning value GDSF, it is possible to compensate for the influence due to the change in the output characteristics of the air flow sensor, and to effectively obtain the above-described effects.

  Further, both the pilot injection timing and the pilot injection amount are controlled according to the learning value GDSF (steps 63, 64, 66 and 67). For this reason, even when a proper combustion state cannot be obtained due to the influence of changes in the properties of the fuel, this influence can be compensated more appropriately. As a result, an appropriate combustion state as represented by the target ignition delay SFCMD can be reliably obtained, so that combustion noise can be reliably suppressed and good fuel consumption and exhaust gas characteristics can be reliably obtained.

  Further, since the learning value GDSF is calculated based on the previous value GDSFZ and the current ignition delay deviation DSF (steps 24 and 25), noise or the like that can be included in the in-cylinder pressure change amount DPV detected by the in-cylinder pressure sensor 31 Even when the actual ignition delay TFACT is temporarily changed due to a change in the actual combustion state or the like, the EGR gas amount, the pilot injection timing, and the pilot injection amount can be controlled while suppressing the influence of the actual ignition delay.

  Further, calculation of the learning value GDSF is prohibited during transient operation of the engine 3 (step 21: YES). Therefore, the control of the amount of EGR gas according to the learning value GDSF can more appropriately compensate for the influence of changes in the properties of the fuel, and as a result, the combustion noise can be more reliably suppressed and the fuel efficiency and fuel consumption can be reduced. The exhaust gas characteristics can be obtained more reliably. Further, when the predetermined time TREF has not elapsed since the previous calculation of the learning value GDSF (step 22: NO), the calculation of the learning value GDSF is prohibited. Therefore, it is possible to reduce the calculation load of the ECU 2 while appropriately compensating for the influence due to the change in the operation characteristics of the EGR device 14.

  In addition, this invention can be implemented in various aspects, without being limited to the described embodiment. For example, in the embodiment, the engine speed NE and the required torque PMCMD are used as the operating state of the internal combustion engine in the present invention, but the detected output torque of the engine 3 and the amount of fresh air sucked into the cylinder 3b. Etc. may be used. Moreover, although both the actual ignition timing TFACT and the actual ignition delay SFACT are used as the combustion state parameters in the present invention, one of them may be used. In addition, for example, the in-cylinder pressure change rate dPθ may be used as long as it represents the combustion state of the fuel in the cylinder 3b instead of at least one of both TFACT and SFACT. Furthermore, in the embodiment, the ignition delay deviation DSF is used for the correction of the target ignition timing TFCMD and the control of the EGR gas amount, the post injection timing, and the post injection amount, but the target ignition delay SFCMD and the actual ignition delay SFACT As long as it is a parameter representing the comparison result or the degree of deviation, for example, the ratio of the other of the two SFCMD and SFACT to the other may be used.

  In the embodiment, the learning value GDSF is calculated by the equation (2). However, the calculation method is not limited to this, and for example, the current ignition delay deviation DSF and the previous value GDSFZ of the learning value are calculated. You may calculate by a weighted average. In addition, the learning value GDSF may be calculated using a plurality of learning values GDSF or ignition delay deviation DSF calculated several times before this time. Furthermore, in the embodiment, both the pilot injection timing and the pilot injection amount are controlled according to the learning value GDSF, but one of the two may be controlled. In the embodiment, the pilot injection timing and the main injection timing are respectively the end timings of the pilot injection and the main injection, but may be start timings.

  Further, in the embodiment, the calculation of the learning value GDSF is prohibited when the condition that the predetermined time TREF has not elapsed since the previous calculation is satisfied, but instead of the condition regarding the predetermined time TREF, For example, it is also within the scope of the present invention to use a condition that the travel distance of the vehicle has not reached a predetermined distance from the previous calculation.

Further, regarding the determination of the transient operation state of the engine 3, at least one of the following conditions (A) to (F) is satisfied instead of or together with the condition based on the torque pressure ratio RTI in the embodiment. Sometimes, it may be determined that the engine 3 is in a transient operation state.
(A) The absolute value of the change amount of the accelerator opening AP is larger than a predetermined value. (B) The absolute value of the change amount of the fuel amount due to the main injection is larger than a predetermined value. (C) The change amount of the vehicle speed. (D) The absolute value of the change amount of the engine speed NE is larger than the predetermined value. (E) The absolute value of the change amount of the required torque PMCMD is larger than the predetermined value.

  In the embodiment, the EGR device 14 is a so-called external EGR device that recirculates the EGR gas to the intake pipe 4 by the EGR pipe 14a. However, a part of the burned gas is allowed to exist in the cylinder 3b as EGR gas. Other devices may be used as long as they are suitable. For example, a so-called internal EGR device in which burned gas remains in the cylinder 3b by controlling the valve timing of the intake valve and exhaust valve of the engine 3 may be used. Furthermore, in the embodiment, the engine 3 as the internal combustion engine in the present invention is a diesel engine for driving a vehicle, and is an engine in which fuel is injected into the cylinder and fuel is self-ignited by compression by the piston. If there are, for example, a gasoline engine, an engine using liquefied petroleum gas as a fuel, an engine for a marine propulsion device such as an outboard motor having a crankshaft arranged in a vertical direction, and other various industrial engines may be used. In addition, it is possible to appropriately change the detailed configuration within the scope of the gist of the present invention.

1 is a diagram schematically showing an internal combustion engine to which a control device according to an embodiment of the present invention is applied. It is a block diagram which shows the control apparatus by embodiment of this invention. It is a flowchart which shows the parameter calculation process for control. It is a flowchart which shows an ignition delay calculation process. It is a flowchart which shows a DSF learning process. It is a flowchart which shows a transient operation determination process. It is a flowchart which shows a request torque calculation process. It is a flowchart which shows an EGR control process. It is a flowchart which shows a pilot injection control process. It is a flowchart which shows a main injection timing control process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control apparatus 2 ECU (Operating state detection means, EGR gas amount control means, combustion state parameter detection means, target combustion state parameter setting means, transient operation determination means, corrected target combustion state parameter calculation means, fuel injection timing correction means , Deviation degree parameter calculation means, learning means, pilot injection control means)
3 Engine 3b Cylinder 14 EGR device 31 In-cylinder pressure sensor (combustion state parameter detection means)
32 Crank angle sensor (operating state detection means)
36 Accelerator opening sensor (operating state detection means)
NE engine speed (detected operating state of internal combustion engine)
PMCMD required torque (detected operating state of internal combustion engine)
EGRACT Actual EGR gas amount (EGR gas amount)
TFACT actual ignition timing (combustion state parameters, ignition timing)
TFCMD target ignition timing (target combustion state parameter)
SFACT Actual ignition delay (combustion state parameter, ignition delay period)
SFCMD Target ignition delay (target combustion state parameter)
DSF ignition delay deviation (comparison result with combustion state parameter, deviation degree parameter)
CTFCMD corrected target ignition timing (corrected target combustion state parameter)
TMICMD target main injection timing (fuel injection timing into the cylinder, main injection timing)
GDSF learning value (learning value of divergence degree parameter)
TREF Predetermined time (predetermined period)

Claims (5)

An internal combustion engine control device for controlling an operation of an internal combustion engine provided with an EGR device that causes a part of burned gas to exist in a cylinder as EGR gas and injecting fuel into the cylinder. ,
An operating state detecting means for detecting an operating state of the internal combustion engine;
EGR gas amount control means for controlling the amount of EGR gas according to the detected operating state of the internal combustion engine;
Combustion state parameter detecting means for detecting a combustion state parameter representing a combustion state of fuel in the cylinder;
Target combustion state parameter setting means for setting a target combustion state parameter that is a target of the combustion state parameter in accordance with the operating state of the internal combustion engine;
Transient operation determination means for determining whether or not the internal combustion engine is in a transient operation state;
By correcting the target combustion state parameter based on the comparison result between the target combustion state parameter and the combustion state parameter when it is determined that the internal combustion engine is in a transient operation state, the corrected target combustion state A corrected target combustion state parameter calculating means for calculating a parameter;
Fuel injection timing correction for correcting the fuel injection timing into the cylinder so that the combustion state parameter becomes the corrected target combustion state parameter when it is determined that the internal combustion engine is in a transient operation state Means,
A control device for an internal combustion engine, comprising:   The combustion state parameter includes at least an ignition timing of fuel supplied into the cylinder, an ignition delay period from the injection timing of fuel into the cylinder to the ignition timing, and a rate of change in pressure in the cylinder. The control apparatus for an internal combustion engine according to claim 1, wherein one is included. A deviation degree parameter calculating means for calculating a deviation degree parameter representing a deviation degree between the target combustion state parameter and the combustion state parameter;
Learning means for calculating a learning value of the divergence degree parameter based on a plurality of divergence degree parameters calculated so far by the divergence degree parameter calculating means;
3. The control device for an internal combustion engine according to claim 1, wherein the EGR gas amount control means controls the amount of the EGR gas according to a learning value of the calculated deviation degree parameter. . In the internal combustion engine, pilot injection and main injection are sequentially performed as fuel injection into the cylinder,
The fuel injection timing correction means corrects the timing of the main injection,
The internal combustion engine according to claim 3, further comprising pilot injection control means for controlling at least one of the timing of the pilot injection and the amount of fuel by the pilot injection in accordance with a learned value of the deviation degree parameter. Control device.   The learning means satisfies at least one of a condition that the internal combustion engine is determined to be in a transient operation state and a condition that a predetermined period has not elapsed since the previous calculation of the learned value of the deviation degree parameter. 5. The control device for an internal combustion engine according to claim 3, wherein calculation of a learning value of the deviation degree parameter is prohibited during operation.

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