Control device for internal combustion engine

Abstract

To increase an output of an internal combustion engine while preventing an injection completion timing from shifting to a retard side with respect to a limit injection completion timing.SOLUTION: An E / G-ECU 100 performs calculation to increase an injection timing correction amount Qh (S23), when an injection completion timing Te is shifted to a retard angle side with respect to a prescribed crank angle Tcm (YES in S22). Thus, a target injection amount Qf is reduced, an injection period Tp is shortened, and the injection completion timing Te is prevented from shifting to a retard angle side with respect to a limit injection completion timing Cm. As a result, a fuel injection amount can be increased in comparison with a conventional one, and an output of the internal combustion engine 1 can be increased.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a control device for an internal combustion engine, and more particularly to a control device for a compression ignition type internal combustion engine. [Background technology]

[0002] There is known a compression ignition type internal combustion engine, such as a diesel engine, in which fuel injected into a combustion chamber from a fuel injection valve is burned by self-ignition.For example, Japanese Patent Application Laid-Open No. 11-159385 discloses a diesel engine that calculates a fuel injection period from detection values ​​of a fuel injection start time and an injection end time, calculates an ignition delay period from detection values ​​of a fuel injection start time and a combustion start time, and corrects the fuel injection pressure to increase so as to shorten the fuel injection period when the ignition delay period is shorter than the fuel injection period, thereby reducing NOx (nitrogen oxides) and PM (particulate matter). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-159385 Summary of the Invention [Problem to be solved by the invention]

[0004] When the fuel injection amount from the fuel injection valve increases, the fuel injection period becomes longer. When the fuel injection period becomes longer, the injection end timing is delayed toward the crank angle side. Become The end of injection is delayed. Become This can cause problems such as an increase in exhaust temperature and increased contamination of the lubricating oil with soot.

[0005] Fuel injection valves have variations in injection characteristics, and the injection characteristics change due to deterioration. For this reason, experiments are conducted in advance to determine the crank angle (limit injection end time) at which injection ends, at which problems such as rising exhaust temperature and increased soot mixing into the lubricating oil begin to occur, and the fuel injection amount is set so that the injection end time falls within the limit injection end time (so that the injection end time is not retarded from the limit injection end time) while taking into account the variations in and changes in the injection characteristics of the fuel injection valve.

[0006] In this way, the fuel injection amount is set taking into consideration the variation and change in the injection characteristics of the fuel injection valve, so the amount of fuel injection is limited, and the output of the internal combustion engine is reduced below the output that should be obtained. Patent Document 1 does not disclose this point.

[0007] The present disclosure has an object to enable an increase in the output of an internal combustion engine while ensuring that the injection end timing falls within the limit injection end timing (so that the injection end timing is not retarded from the limit injection end timing). [Means for solving the problem]

[0008] The present disclosure relates to a control device for an internal combustion engine of a compression autoignition type internal combustion engine having a fuel injection valve that injects fuel into a combustion chamber, and the control device includes an injection end timing acquisition unit that acquires an injection end timing at which fuel injection by the fuel injection valve ends, and an injection amount calculation unit that reduces the fuel injection amount when the injection end timing is on the retard side of a predetermined crank angle.

[0009] According to this configuration, the injection amount calculation unit reduces the fuel injection amount when the injection end timing acquired by the injection end timing acquisition unit is more retarded than the predetermined crank angle. Since the injection end timing is acquired and the fuel injection amount is reduced when the acquired injection end timing is more retarded than the predetermined crank angle, it is possible to keep the injection end timing within the limit injection end timing (it is possible to prevent the injection end timing from being more retarded than the limit injection end timing) without setting the fuel injection amount taking into account the variation and characteristic change of the injection characteristic of the fuel injection valve, and it is possible to increase the output of the internal combustion engine.

[0010] Preferably, the injection amount calculation section may be configured to correct the basic injection amount calculated in accordance with the load by decreasing it when the injection end timing is retarded from a predetermined crank angle.

[0011] According to this configuration, it is possible to bring the injection end timing within the limit injection end timing by a simple method of correcting the basic injection amount to decrease it.

[0012] Preferably, the injection amount calculation unit may be configured to calculate a basic injection amount according to the load from a pre-stored map, and to reduce the fuel injection amount by rewriting the map when the injection end timing is retarded from a specified crank angle.

[0013] According to this configuration, the fuel injection amount is reduced by rewriting the map for calculating the basic injection amount, so that a map that takes into account the change in the characteristics of the fuel injection valve can be obtained.

[0014] Preferably, the predetermined crank angle is set so that the injection end timing is delayed from the predetermined crank angle. Become and may be the crank angle at which the amount of soot mixed into the lubricating oil becomes equal to or greater than a predetermined value.

[0015] According to this configuration, the fuel injection amount can be set large within a range that allows the injection end timing to fall within the limit injection end timing, and the output of the internal combustion engine can be increased.

[0016] Preferably, the predetermined crank angle is set so that the injection end timing is delayed from the predetermined crank angle. Become The crank angle may be a set crank angle that is advanced from the crank angle at which the amount of soot mixed into the lubricating oil becomes equal to or exceeds a predetermined value.

[0017] According to this configuration, the fuel injection amount is set with a margin of the set crank angle, so that even if there is variation in the accuracy of the injection end timing acquisition unit, the injection end timing can be reliably set to the limit injection end timing. Effect of the Invention

[0018] According to the present disclosure, it is possible to increase the output of the internal combustion engine while ensuring that the injection end timing falls within the limit injection end timing. [Brief description of the drawings]

[0019] [Figure 1] 1 is an overall configuration diagram of an internal combustion engine according to an embodiment of the present invention; [Diagram 2] 11 is a diagram showing the relationship between the injection end timing and the amount of soot mixed into the lubricating oil. FIG. [Diagram 3] 4 is a diagram showing the relationship between the fuel injection amount and the injection end timing when the internal combustion engine 1 is operating at full load. FIG. [Figure 4] 4 is a flowchart showing a fuel injection control process executed by the E / G-ECU 100. [Diagram 5] 4 is a flowchart showing a correction amount calculation control process executed by an E / G-ECU 100. [Figure 6] 4 is a diagram showing the relationship between the fuel injection amount and the injection end timing when the internal combustion engine 1 is operating at full load in the present embodiment. FIG. [Figure 7] 10 is a flowchart showing a basic injection amount update control process executed by an E / G-ECU 100 in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0021] 1 is an overall configuration diagram of an internal combustion engine according to this embodiment. The internal combustion engine 1 is a diesel engine that injects fuel from a fuel injection valve (injector) 14 into a combustion chamber formed in a cylinder (cylinder) 12 of an engine body 10, and performs compression self-ignition. An air cleaner 22, an intercooler 24, and an intake throttle valve (electronically controlled throttle) 26 are provided in an intake passage 20 of the internal combustion engine 1. Fresh air from which foreign matter has been removed by the air cleaner 22 is supercharged (compressed) by a compressor 32 of a turbocharger 30, cooled by the intercooler 24, supplied to an intake manifold 28, and supplied to each combustion chamber from an intake port.

[0022] In this embodiment, the fuel injection system employs a common rail fuel injection system (accumulator type fuel injection device), in which fuel from a fuel tank 40 is supplied to a common rail 42 by a high-pressure pump 41, and the high-pressure fuel accumulated in the common rail 42 is injected from a fuel injection valve 14 into the combustion chamber.

[0023] The fuel injection valve 14 is composed of a fuel injection nozzle that injects fuel into the combustion chamber, a piezoelectric element that drives a nozzle needle housed in the fuel injection nozzle in a valve opening direction, and a needle biasing means such as a spring that biases the nozzle needle in a valve closing direction, and the fuel injection is controlled by energizing and de-energizing the piezoelectric element (ON / OFF). When the piezoelectric element is energized to open the nozzle needle through a plurality of injection holes formed at the tip of the nozzle body, high-pressure fuel accumulated in the common rail 42 is injected into the combustion chamber. The fuel injection valve 14 is provided with a fuel pressure sensor 16 that detects the fuel pressure in the fuel passage from the common rail 42 to the injection holes. The nozzle needle may be driven to open by an electromagnetic solenoid or the like.

[0024] Exhaust gas discharged from the combustion chamber is collected in an exhaust manifold 50 and released into the outside air via an exhaust passage 52. In the exhaust passage 52, from the upstream side, the turbine 34 of the turbocharger 30, an oxidation catalyst 70, a DPF (Diesel Particulate Filter) 72, a selective reduction catalyst 74, and an oxidation catalyst 76 are provided. The oxidation catalyst 70 oxidizes carbon monoxide (CO) in the exhaust gas to carbon dioxide (CO2), and oxidizes hydrocarbons (HC) in the exhaust gas to water (H2O) and CO2. It also oxidizes nitrogen monoxide (NO) in the exhaust gas to nitrogen dioxide (NO2).

[0025] The DPF 72 collects particulate matter in the exhaust gas and purifies the exhaust gas by appropriately burning and removing the collected particulate matter. The selective catalytic reduction catalyst (hereinafter also referred to as SCR (Selective Catalytic Reduction) catalyst) 74 reduces and purifies NOx in the exhaust gas. The oxidation catalyst 76 oxidizes ammonia discharged (slips) from the SCR catalyst 74 and purifies the ammonia.

[0026] A urea addition valve (urea water injection injector) 80 is provided in the exhaust passage upstream of the SCR catalyst 74, and urea water pressurized by a pump (not shown) from a urea water tank 82 is injected from the urea addition valve 80 into the exhaust passage 52 upstream of the SCR catalyst 74. The urea water supplied to the exhaust passage upstream of the SCR catalyst 72 is hydrolyzed to generate ammonia, and this ammonia is used as a reducing agent to reduce and purify NOx.

[0027] In this embodiment, an E / G-ECU (Electronic Control Unit) 100 is provided as a control device for the internal combustion engine 1. The E / G-ECU 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) that stores processing programs and the like, a memory 102 such as a RAM (Random Access Memory) that temporarily stores data, an input / output port (not shown) for inputting and outputting various signals, and the like, and executes predetermined arithmetic processing based on information stored in the memory (ROM and RAM) 102 and information from various sensors to control the fuel injection valve 14 and the like.

[0028] The various sensors include, for example, a fuel pressure sensor 16, an accelerator opening sensor 121, a crank angle sensor 122, and a coolant temperature sensor 123. The fuel pressure sensor 16 detects the fuel pressure P in the fuel passage from the common rail 42 to the injection hole. The accelerator opening sensor 121 detects the accelerator pedal operation amount (accelerator opening) AP. The crank angle sensor 122 detects the crank angle CA of the internal combustion engine 1. The coolant temperature sensor 123 detects the coolant temperature THW of the internal combustion engine 1.

[0029] When the amount of fuel injected from the fuel injection valve 14 increases, the fuel injection period (the period during which the fuel injection valve 14 is open) becomes longer. When the fuel injection period becomes longer, the injection end timing is shifted toward the retard side of the crank angle. Become FIG. 2 shows the relationship between the injection end timing and the amount of soot mixed into the lubricating oil. In FIG. 2, the horizontal axis is the injection end timing, which indicates the crank angle (CA) after top dead center (ATDC). The vertical axis is the soot concentration of the lubricating oil. As shown in FIG. 2, when the injection end timing is retarded from the crank angle Cm, the soot concentration of the lubricating oil (amount of soot in the oil) increases. Also, when the injection end timing is retarded, Become The crank angle Cm at which the amount of soot in the oil starts to increase is also called the limit injection end timing Cm.

[0030] FIG. 3 is a diagram showing the relationship between the fuel injection amount and the injection end timing during full load operation of the internal combustion engine 1. In FIG. 3, the upper part shows the injection command of the fuel injection valve 14. When the injection command is ON, electricity is applied to the piezoelectric element, the injection hole of the fuel injection valve 14 opens, and fuel is injected. In FIG. 3, the lower part shows the injection rate of the fuel injection. In the example shown in FIG. 3, two-stage injection of pilot injection and main injection is performed, and the pilot injection is performed first, followed by the main injection. When the injection command is ON and electricity is applied to the piezoelectric element, fuel is injected from the injection hole after an injection delay, and when the injection command is OFF and electricity is stopped, fuel injection stops with a delay. In the lower part of FIG. 3, the area surrounded by the injection rate corresponds to the fuel injection amount.

[0031] The larger the fuel injection amount, the greater the output the internal combustion engine 1 can generate. Therefore, when the internal combustion engine 1 is operating at full load, such as during WOT (Wide Open Throttle), it is desirable to make the fuel injection amount as large as possible. However, the fuel injection valve 14 has variations in injection characteristics, and the injection characteristics change due to deterioration. For this reason, the margin A is set taking into consideration the variations and characteristic changes in the injection characteristics of the fuel injection valve 14, and the injection period (energization period) Tp is obtained so that the injection end timing is advanced by the margin A from the limit injection end timing Cm, and the fuel injection amount during full load operation is set. As a result, even if there are variations and characteristic changes in the injection characteristics of the fuel injection valve 14, the fuel injection amount can be set so that the injection end timing falls within the limit injection end timing Cm (so that the injection end timing is not retarded from the limit injection end timing Cm).

[0032] When the fuel injection amount is set in this manner, as shown in the shaded area in FIG. 3, the fuel injection amount is limited by the fuel injection amount corresponding to the margin A, so that the output of the internal combustion engine 1 during full load operation is reduced and the performance of the internal combustion engine 1 cannot be effectively utilized.

[0033] In this embodiment, the injection end timing is obtained, and when the injection end timing is more retarded than the limit injection end timing Cm, the fuel injection amount is reduced so that the injection end timing falls within the limit injection end timing Cm (so that the injection end timing does not become more retarded than the limit injection end timing Cm), while enabling the output of the internal combustion engine 1 to be increased.

[0034] FIG. 4 is a flowchart showing the process of fuel injection control executed by the E / G-ECU 100. This flowchart is repeatedly processed during operation of the internal combustion engine 1 (from when the ignition switch is turned on until the ignition switch is turned off). In step (hereinafter, step is abbreviated as S) 10, it is determined whether or not the DPF 72 is being regenerated. During regeneration of the DPF 72, in which particulate matter trapped by the DPF 72 is burned and removed, the fuel injection timing is retarded and exhaust stroke injection or the like is performed to increase the exhaust temperature, so that the injection end timing is retarded from the limit injection end timing Cm. Therefore, if the DPF 72 is being regenerated and a positive determination is made in S10, the current routine is terminated. (In this case, a process of fuel injection control for regenerating the DPF 72 is executed separately.) If the DPF 72 is not being regenerated, a negative determination is made and the routine proceeds to S11.

[0035] In S11, the number of injection stages is calculated based on the accelerator opening AP and the engine speed NE. The engine speed NE can be calculated based on the crank angle CA detected by the crank angle sensor 122.

[0036] In the next S12, a basic injection amount Q is calculated based on the accelerator opening AP and the engine speed NE. The basic injection amount Q is stored in the memory 102 as a map using the accelerator opening AP and the engine speed NE as parameters. Note that, if the number of injection stages and the basic injection amount are specified in the optimal injection map using the accelerator opening AP and the engine speed NE as parameters, S11 and S12 may be processed simultaneously.

[0037] In S13, the target injection amount Qf is calculated. For example, the target injection amount Qf is calculated as "target injection amount Qf = Q + Qt + Qa - Qh". Here, Qt is a warm-up correction amount, which is calculated based on the cooling water temperature THW. Qa is an acceleration correction amount, which is calculated based on the change amount ΔAP of the accelerator opening AP. Qh is an injection timing correction amount, which is calculated by the correction amount calculation control (FIG. 5) described later. After the internal combustion engine 1 has finished warming up, "warm-up correction amount Qt = 0" is set, and when the change amount ΔAP of the accelerator opening AP is equal to or less than a predetermined value, "acceleration correction amount Qa = 0" is set.

[0038] In the next S14, the injection start time T is calculated based on the engine speed NE and the target injection amount Qf. Then, in S15, the injection period (energization period) Tp is calculated based on the fuel pressure Pc in the common rail 42, the engine speed NE, and the target injection amount Qf, and the current routine is ended.

[0039] When the injection start time T and the injection period Tp are calculated by the fuel injection control process, the injection command is ON from the injection start time T until the end of the injection period Tp. As a result, while the injection command is ON, electricity is applied to the drive actuator (piezoelectric element or the like) of the fuel injection valve 14 via an injection valve drive circuit (not shown), and fuel is injected from the fuel injection valve 14. Note that the injection start time T and the injection period Tp are calculated for each injection stage, and the number of injection stages calculated in S11 may include (as information) the allocation rate of the target injection amount Qf to each injection stage.

[0040] In S12, the basic injection amount Q is calculated based on the accelerator opening AP and the engine speed NE, but the basic injection amount Q may be calculated by so-called torque demand control. For example, a required shaft torque may be calculated from the accelerator opening AP and the engine speed NE, and the required indicated torque (combustion pressure torque) may be obtained by adding the consumed torque of the internal combustion engine 1 to this required shaft torque, and the basic injection amount Q may be calculated based on this required indicated torque. In either case, the basic injection amount Q is calculated according to the load of the internal combustion engine 1.

[0041] 5 is a flowchart showing the process of correction amount calculation control executed by the E / G-ECU 100. This flowchart is repeatedly processed while the internal combustion engine 1 is in operation. In S20, it is determined whether or not the DPF 72 is being regenerated. If the DPF 72 is being regenerated, a positive determination is made and the current routine is terminated. If the DPF 72 is not being regenerated, a negative determination is made and the routine proceeds to S21.

[0042] In S21, the injection end timing Te is acquired. In this embodiment, the injection end timing Te is calculated using the fuel pressure P in the fuel passage from the common rail 42 to the injection hole, detected by the fuel pressure sensor 16. For example, when the fuel pressure P increases with the injection command being OFF, the injection end timing Te is calculated based on the timing at which the derivative value of the fuel pressure P becomes maximum. Note that the method of calculating the injection end timing Te using the derivative value of the fuel pressure P is publicly known, and therefore a detailed description thereof will be omitted. (For example, see JP 2019-65721 A.) In the next step S22, it is determined whether the injection end timing Te obtained in step S21 is equal to or greater than a predetermined crank angle Tcm. In this embodiment, the injection end timing Te obtained in step S21 is obtained as the value of the crank angle CA at ATDC. If the injection end timing Te is greater than the predetermined crank angle Tcm, the injection end timing Te is retarded from the predetermined crank angle Tcm. The predetermined crank angle Tcm is a value advanced from the limit injection end timing Cm by a margin a. The margin a is set, for example, taking into consideration the calculation variation of the injection end timing Te, and is set in advance by experiment or the like as a value smaller than the margin A in FIG. 3.

[0043] If the injection end time Te is equal to or greater than the predetermined crank angle Tcm and is retarded by the predetermined crank angle Tcm or more, a positive determination is made in S22 and the program proceeds to S23. If the injection end time Te is less than the predetermined crank angle Tcm and is advanced by the predetermined crank angle Tcm, a negative determination is made in S22 and the program proceeds to S24.

[0044] In S23, a predetermined value α is added to the injection timing correction amount Qh, and the current routine is terminated. In S24, it is determined whether the injection timing correction amount Qh is equal to or less than 0. If the injection timing correction amount Qh is greater than 0, a negative determination is made and the program proceeds to S15, whereas if the injection timing correction amount Qh is equal to or less than 0, a positive determination is made and the program proceeds to S26.

[0045] In S25, a predetermined value β is subtracted from the injection timing correction amount Qh, and the current routine is terminated. In S26, the injection timing correction amount Qh is set to 0, and the current routine is terminated.

[0046] In this embodiment, in the correction amount calculation control, when the injection end time Te is on the retard side of the predetermined crank angle Tcm or more, the injection timing correction amount Qh is calculated to be large (S23). Then, in the fuel injection control, the target injection amount Qf is calculated by subtracting the injection timing correction amount Qh from the basic injection amount Q (S13). Therefore, when the injection end time Te is on the retard side of the predetermined crank angle Tcm, the target injection amount Qf decreases and the injection period Tp becomes shorter. Then, when the injection period Tp becomes shorter and the injection end time Te is on the advance side of the predetermined crank angle Tcm, the injection timing correction amount Qh is calculated to be small and is finally set to 0 (S24 to S26).

[0047] FIG. 6 is a diagram showing the relationship between the fuel injection amount and the injection end timing during full load operation of the internal combustion engine 1 in this embodiment. In FIG. 6, the upper part shows the injection command of the fuel injection valve 14, and the lower part shows the injection rate of the fuel injection. In this embodiment, when the injection end timing Te becomes more retarded than the predetermined crank angle Tcm, the target injection amount Qf is decreased to control the injection period Tp to be shorter. Therefore, as shown in FIG. 6, even if the predetermined crank angle Tcm is set by making the margin a smaller than the margin A (see FIG. 3) that takes into account the variation and characteristic change of the injection characteristic of the fuel injection valve 14, the injection end timing Te can be kept within the limit injection end timing Cm (the injection end timing can be prevented from becoming more retarded than the limit injection end timing Cm). Therefore, without taking into account the variations and characteristic changes in the injection characteristics of the fuel injection valve 14, it is possible to set the fuel injection amount by limiting the fuel injection amount by the fuel injection amount equivalent to the margin a (see the shaded area in Figure 6), and since the fuel injection amount can be increased compared to the conventional method, the output of the internal combustion engine 1 can be increased and the performance of the internal combustion engine 1 can be effectively utilized.

[0048] In the above embodiment, the margin a is set in consideration of the calculation variation of the injection end timing Te. However, if the calculation accuracy of the injection end timing Te is high, the margin a may be set to 0 (the margin a may not be necessary). For example, if a stroke sensor (displacement sensor) is provided on the nozzle needle of the fuel injection valve 14 and a configuration is made that can detect that the nozzle needle has closed the injection hole, the injection end timing Te can be detected with high accuracy. In this case, the margin a may be set to 0 and the predetermined crank angle Tcm may be set as the limit injection end timing Cm. Even in this case, the predetermined crank angle Tcm may be set using a margin smaller than the margin a in consideration of the control variation of the fuel injection control.

[0049] (Modification) In the above embodiment, the target injection amount Qf is obtained by calculating the injection timing correction amount Qh and correcting the basic injection amount Q by decreasing it. However, the configuration for decreasing the fuel injection amount (target injection amount Qf) is not limited to this.

[0050] 7 is a flowchart showing the basic injection amount update control process executed by the E / G-ECU 100 in the modified example. This flowchart is repeatedly processed while the internal combustion engine 1 is in operation. In S30, it is determined whether the DPF 72 is being regenerated. If the DPF 72 is being regenerated, a positive determination is made and the current routine is terminated. If the DPF 72 is not being regenerated, a negative determination is made and the routine proceeds to S31.

[0051] In S31, similar to S21 in Fig. 6, the injection end time Te is acquired, and then the routine proceeds to S32. In S32, it is determined whether the injection end time Te is equal to or greater than a predetermined crank angle Tcm. If the injection end time Te is less than the predetermined crank angle Tcm and is on the advanced side of the predetermined crank angle Tcm, a negative determination is made in S32, and the current routine is terminated.

[0052] If the injection end time Te is equal to or greater than the predetermined crank angle Tcm and is retarded by more than the predetermined crank angle Tcm, an affirmative determination is made in S32 and the routine proceeds to S33. In S33, a new basic injection amount Q is calculated by subtracting a predetermined value γ from the basic injection amount Q in the fuel injection at the injection end time Te obtained in S31. Then, in the map for calculating the basic injection amount, the corresponding value of the basic injection amount Q is rewritten to the new value of the basic injection amount Q, the map is updated, and the current routine is terminated.

[0053] In this modification, fuel injection is also performed from the fuel injection valve 14 by the fuel injection control of Fig. 4. In the modification, since the injection timing correction amount Qh is not calculated, the target injection amount Qf is calculated as "Qf = Q + Qt + Qa" in S13.

[0054] According to this modification, the injection end timing Te is set to a predetermined crank angle T cmWhen the injection end time Te is more retarded than the specified crank angle Tcm, the corresponding value of the basic injection amount Q in the map for calculating the basic injection amount is rewritten to the new basic injection amount Q, so that the basic injection amount Q becomes a smaller value. Therefore, when the injection end time Te becomes more retarded than the specified crank angle Tcm, the target injection amount Qf is reduced and the injection period Tp is controlled to be shorter, thereby achieving the same effects as those of the above embodiment. Also, the value of the basic injection amount Q when the injection end time Te becomes more retarded than the specified crank angle Tcm is rewritten to a smaller value and the map is updated, so that a map that takes into account changes in the characteristics of the fuel injection valve 14 can be obtained. The updated map is used to calculate the basic injection amount Q, so that when the injection end time Te becomes more retarded than the specified crank angle T cm This can prevent the angle from becoming further retarded.

[0055] In the above embodiment and modified example, when the DPF 72 is not being regenerated, the injection end timing Te is set to a predetermined crank angle T cm If the injection end timing Te is at a predetermined crank angle T cm The injection end timing Te becomes more retarded only when the load of the internal combustion engine 1 is large and the fuel injection amount is large. Therefore, when the condition that the DPF 72 is not being regenerated and the load of the internal combustion engine 1 is high, for example, when the condition "the accelerator opening AP is a predetermined value (for example, 90%) or more" is satisfied, the injection end timing Te becomes more retarded than the predetermined crank angle T cm Alternatively, it may be determined whether the angle is further retarded.

[0056] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0057] 1 internal combustion engine, 10 engine body, 12 cylinder, 14 fuel injection valve, 16 fuel pressure sensor, 20 intake passage, 22 air cleaner, 24 intercooler, 26 intake throttle valve, 28 intake manifold, 30 turbocharger, 32 compressor, 34 turbine, 40 fuel tank, 41 high pressure pump, 42 common rail, 50 exhaust manifold, 52 exhaust passage, 54 bypass passage, 70 oxidation catalyst, 72 DPF, 74 selective catalytic reduction catalyst (SCR catalyst), 76 oxidation catalyst, 80 urea addition valve, 82 urea water tank, 100 E / G-ECU, 101 CPU, 102 memory, 121 accelerator opening sensor, 122 crank angle sensor, 123 coolant temperature sensor.

Claims

1. A control device for a multi-cylinder compression ignition type internal combustion engine having a fuel injection valve that injects fuel into a combustion chamber, The control device includes: an injection end timing acquisition unit that acquires an injection end timing at which fuel injection by the fuel injection valve is ended; an injection amount calculation unit that reduces a fuel injection amount when the injection end timing is retarded from a predetermined crank angle, the injection amount calculation unit calculates a basic injection amount according to a load from a pre-stored map, and when the injection end timing is on the retard side of the predetermined crank angle, calculates a new basic injection amount by subtracting a predetermined value from the calculated basic injection amount, rewrites a corresponding value of the basic injection amount in the map to the new basic injection amount, and updates the map, thereby reducing the fuel injection amount; A control device for an internal combustion engine, wherein the specified crank angle is a crank angle at which soot mixing into lubricating oil becomes equal to or exceeds a specified value when the injection end timing becomes more retarded than the specified crank angle.

2. A control device for a multi-cylinder compression ignition type internal combustion engine having a fuel injection valve that injects fuel into a combustion chamber, comprising: The control device includes: an injection end timing acquisition unit that acquires an injection end timing at which fuel injection by the fuel injection valve is ended; an injection amount calculation unit that reduces a fuel injection amount when the injection end timing is retarded from a predetermined crank angle, the injection amount calculation unit calculates a basic injection amount according to a load from a pre-stored map, and when the injection end timing is on the retard side of the predetermined crank angle, calculates a new basic injection amount by subtracting a predetermined value from the calculated basic injection amount, rewrites a corresponding value of the basic injection amount in the map to the new basic injection amount, and updates the map, thereby reducing the fuel injection amount; A control device for an internal combustion engine, wherein the specified crank angle is a crank angle that is advanced by a set crank angle from the crank angle at which soot mixing into the lubricating oil exceeds a specified value when the injection end timing is retarded from the specified crank angle.

Images