JP2023158749A - Control device of compression self-ignition type internal combustion engine - Google Patents

Abstract

To provide a control device of a compression self-ignition type internal combustion engine which can calculate a further-accurate estimation ignition delay time.SOLUTION: A control device of a compression self-ignition type internal combustion engine has: a normal multistage injection execution unit for executing multistage injection including main injection and pilot injection to a one-time combustion stroke of the internal combustion engine by controlling an injector; an estimated ignition delay time calculation unit for acquiring an estimated ignition delay time until the main injection is generated after a start of the main injection on the basis of an operation state of the internal combustion engine; a confirmation single-stage injection execution unit for executing confirmation single-stage injection for injecting a prescribed quantity of fuel by the single-stage injection by only the main injection to the internal combustion engine whose rotation number is decreased due to a fuel cut; a torque equivalent amount detection unit for detecting a torque equivalent amount corresponding to torque which is generated in the internal combustion engine by the confirmation single-stage injection; a correction time calculation unit for calculating a correction time for correcting the estimated ignition delay time on the basis of the detected torque equivalent amount; and an estimated ignition delay time correction unit for correcting the estimated ignition delay time.SELECTED DRAWING: Figure 1

Description

The present invention relates to a control device for a compression self-ignition internal combustion engine that controls an injector that injects fuel into the compression self-ignition internal combustion engine.

Conventionally, in compression self-ignition internal combustion engines installed in automobiles, etc., for one combustion stroke, main injection is the main fuel injection, and pilot injection is the fuel injection performed prior to the main injection. Multi-stage injection including When performing multi-stage injection, the internal combustion engine control device estimates the ignition delay time (the delay time from the start of main injection to the occurrence of main combustion, which is the main combustion) based on the operating condition. Combustion parameters are calculated based on the ignition delay time.

Combustion parameters are parameters related to multistage injection performed in a compression self-ignition internal combustion engine. Based on the parameters, the control device determines, for example, the total injection amount from the injector for one combustion stroke of the internal combustion engine, into the main injection amount by main injection and the pilot fuel injection which is performed prior to main injection. Allocate to pilot injection amount by injection. Ideal combustion can be generated by multistage injection based on combustion parameters that achieve the estimated ignition delay time.

In this way, in a compression self-ignition internal combustion engine, combustion parameters are determined based on the estimated ignition delay time, so it is necessary to obtain sufficiently high estimation accuracy of the ignition delay time. For example, in Patent Document 1, ignition delay includes physical ignition delay (time required for evaporation and mixing of fuel droplets) and chemical ignition delay (time required for chemical combination and decomposition of fuel vapor and oxidation heat generation). The total ignition delay period is calculated based on these ignition delay periods. Specifically, the period from the start of pilot injection until the equivalence ratio in the spray drops below the combustible equivalence ratio in the spray is determined as the physical ignition delay period, and the physical ignition delay period The chemical ignition delay is calculated based on the temperature and pressure inside the combustion chamber at the time when the in-spray equivalence ratio of the injected fuel reaches the above-mentioned in-spray combustible equivalence ratio. The total ignition delay period is calculated from this physical ignition delay and chemical ignition delay.

Re-table No. 2012-046312

However, in an environment where the intake manifold (hereinafter referred to as intake manifold) temperature is low, for example in an environment of 10 degrees Celsius or less, the error between the calculated estimated ignition delay time and the actual ignition delay time may fall outside of the allowable range. be. Therefore, if we use a method of determining combustion parameters that assumes that the estimated ignition delay time is calculated with high accuracy (for example, the error with respect to the actual ignition delay time is within the range of -10% to 10%), If injection is performed based on combustion parameters in an intake manifold environment, there is a risk of misfire.

Therefore, in the past, priority has been given to misfire prevention over ideal combustion, and combustion parameters have been determined on the assumption that the estimated ignition delay time varies from the actual ignition delay time. While this can provide the effect of preventing misfires, it may result in combustion that deviates slightly from ideal combustion, and for example, combustion noise may become slightly louder. If the estimated ignition delay time can be obtained with high accuracy regardless of the intake manifold temperature, there is no need to prioritize misfire prevention, and ideal combustion without the risk of misfire can be achieved.

The present invention was created in view of these points, and provides a compression self-ignition internal combustion engine that is capable of calculating a more accurate estimated ignition delay time and realizing more ideal combustion. The object of the present invention is to provide a control device for the following.

In order to solve the above problems, a control device for a compression self-ignition internal combustion engine according to the present disclosure controls an injector to perform main injection, which is the main fuel injection, for one combustion stroke of the internal combustion engine. and a normal multi-stage injection execution unit that performs a multi-stage injection including a pilot injection which is a fuel injection performed prior to the main injection, and a normal multi-stage injection execution unit that performs a multi-stage injection after starting the main injection based on the operating state of the internal combustion engine. An estimated ignition delay time calculation unit that calculates an estimated ignition delay time that is an estimated value of the ignition delay time that is the delay time until main combustion occurs, and controls the injector to rotate by cutting fuel during deceleration. a confirmation single-stage injection execution unit that performs a confirmation single-stage injection in which a predetermined amount of fuel is injected by a single-stage injection of only the main injection to the internal combustion engine that is inertly rotating while the number of fuel is decreasing; a torque equivalent amount detection unit that detects a torque equivalent amount corresponding to the torque generated in the internal combustion engine by the confirmation single-stage injection; the detected torque equivalent amount; and the temperature of the intake manifold of the internal combustion engine or the internal combustion engine. an intake air temperature that is the temperature of the intake air of and an ignition delay time correction section.

According to this, if the ignitability in the cylinder where the air is compressed and heated is good, the fuel from the single-stage injection for confirmation will burn in a short period of time, resulting in a large amount of torque, and if the ignitability is poor, it will burn slowly, resulting in a large amount of torque. The amount becomes smaller. Therefore, the torque equivalent amount obtained in the single-stage confirmation injection can be used as an indicator of ignitability. Furthermore, the temperature of the intake manifold and the temperature of the intake air are directly related to the ignitability within the cylinder. Therefore, since the estimated ignition delay time is corrected by focusing on two values that correlate with the actual ignition performance in the cylinder, it is possible to calculate a more accurate estimated ignition delay time.

In the control device for the compression self-ignition internal combustion engine, the torque equivalent amount detection section detects the rotation speed of the internal combustion engine immediately before executing the confirmation single-stage injection and the rotation speed increased by the confirmation single-stage injection. The torque equivalent amount may be determined based on the amount of variation in the rotational speed.

According to this, for example, the rotational speed increases as a result of performing a single-stage confirmation injection at 2,000 rpm (for example, 10 rpm), and the rotational speed increases as a result of implementing a single-stage confirmation injection at 1,000 rpm (for example, 20 rpm). However, when the two (the number of rotations immediately before the confirmation single-stage injection and the amount of increase in rotation) are multiplied together, they become approximately the same value (for example, 20,000 rpm^2). Therefore, the torque equivalent amount determined in this way is suitable as an index of ignition performance, and it is possible to calculate a more accurate estimated ignition delay time.

In the above-mentioned control device for a compression self-ignition internal combustion engine, the confirmation single-stage injection execution unit performs the confirmation on the internal combustion engine that is inertly rotating while the rotational speed decreases due to fuel cut during deceleration. The single-stage injection is performed multiple times consecutively so as not to cause combustion, and the torque equivalent amount is determined by the torque equivalent amount detection unit for each of the plurality of times, and the torque equivalent amount is determined for each of the plurality of times. The torque equivalent amount for calculating the correction time may be obtained by averaging the torque equivalent amount of times.

According to this, by taking the average, the variation in the torque equivalent amount obtained for each confirmation single-stage injection is suppressed, so the estimated ignition delay time is calculated based on the torque equivalent amount obtained from one confirmation single-stage injection. It is possible to calculate a more accurate estimated ignition delay time than when correcting the ignition delay time.

FIG. 1 is a diagram illustrating an example of the overall schematic configuration of a diesel engine system. It is a figure showing an example of multi-stage injection. It is a flow chart explaining an example of processing (crank angle synchronization processing) of a control device. 9 is a flowchart illustrating details of processing SA100 in the flowchart of FIG. 8. FIG. 9 is a flowchart illustrating details of processing SA200 in the flowchart of FIG. 8. FIG. 9 is a flowchart illustrating details of processing SA300 in the flowchart of FIG. 8. FIG. 9 is a flowchart illustrating details of processing SA000 in the flowchart of FIG. 8. FIG. 9 is an operation waveform for explaining an example of an operation according to the process of the flowchart shown in FIG. 8. FIG. 6 is a diagram showing an example of torque equivalent amount, intake manifold temperature, and correction time characteristics stored in a storage device.

●[Overall configuration of diesel engine system 1 (Figure 1)]
EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. First, an example of the overall configuration of a diesel engine system 1 having a compression self-ignition diesel engine 10 will be described with reference to FIG. In the description of this embodiment, a diesel engine system 1 mounted on a vehicle will be described as an example.

The entire system will be described below in order from the intake side to the exhaust side. An air cleaner (not shown) and an intake flow rate detection means 21 (for example, an intake flow rate sensor) are provided on the inflow side of the intake pipe 11A. The intake air flow rate detection means 21 outputs a detection signal corresponding to the flow rate of air taken in by the diesel engine 10 to the control device 50. Further, the intake air flow rate detection means 21 is provided with an intake air temperature detection means 28A (for example, an intake air temperature sensor). The intake air temperature detection means 28A outputs a detection signal corresponding to the temperature of the intake air passing through the intake air flow rate detection means 21 to the control device 50.

The outflow side of the intake pipe 11A is connected to the inflow side of the compressor 35, and the outflow side of the compressor 35 is connected to the inflow side of the intake pipe 11B. The turbo supercharger 30 includes a compressor 35 having a compressor impeller 35A, and a turbine 36 having a turbine impeller 36A. The compressor impeller 35A is rotationally driven by a turbine impeller 36A that is rotationally driven by the energy of the exhaust gas, and supercharges the intake air flowing in from the intake pipe 11A by force feeding it to the intake pipe 11B.

The intake pipe 11A on the upstream side of the compressor 35 is provided with a compressor upstream pressure detection means 24A. The compressor upstream pressure detection means 24A is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure of intake air in the intake pipe 11A on the upstream side of the compressor 35 to the control device 50. A compressor downstream pressure detection means 24B is provided in the intake pipe 11B on the downstream side of the compressor 35 (a position between the compressor 35 and the intercooler 16 in the intake pipe 11B). The compressor downstream pressure detection means 24B is, for example, a pressure sensor, and outputs a detection signal corresponding to the pressure of intake air in the intake pipe 11B downstream of the compressor 35 to the control device 50.

In the intake pipe 11B, an intercooler 16 is arranged on the upstream side, and a throttle device 48 is arranged on the downstream side of the intercooler 16. The intercooler 16 is disposed downstream of the compressor downstream pressure detection means 24B, and lowers the temperature of the intake air supercharged by the compressor 35. An intake air temperature detection means 28B (for example, an intake air temperature sensor) is provided between the intercooler 16 and the throttle device 48. The intake air temperature detection means 28B outputs a detection signal corresponding to the temperature of the intake air whose temperature has been lowered by the intercooler 16 to the control device 50.

The throttle device 48 drives a throttle valve that adjusts the opening degree of the intake pipe 11B based on a control signal from the control device 50, and can adjust the intake flow rate. The control device 50 outputs a control signal to the throttle device 48 based on the detection signal from the throttle opening detection means 48S (for example, a throttle opening sensor) and the target throttle opening, so as to control the throttle provided in the intake pipe 11B. The opening degree of the valve can be adjusted. The control device 50 determines a target throttle opening based on the amount of accelerator pedal depression detected based on the detection signal from the accelerator pedal depression amount detection means 25 and the operating state of the diesel engine 10 .

The accelerator pedal depression amount detection means 25 is, for example, an accelerator pedal depression angle sensor, and is provided on the accelerator pedal. The control device 50 is capable of detecting the amount of depression of the accelerator pedal by the driver based on the detection signal from the accelerator pedal depression amount detection means 25.

The outflow side of the EGR pipe 13 is connected to the intake pipe 11B on the downstream side of the throttle device 48. The outflow side of the intake pipe 11B is connected to the inflow side of the intake manifold 11C, and the outflow side of the intake manifold 11C is connected to the inflow side of the diesel engine 10. The intake manifold 11C is provided with an intake manifold pressure detection means 24C. The intake manifold pressure detection means 24C is, for example, a pressure sensor, and outputs a detection signal to the control device 50 according to the pressure of intake air in the intake manifold 11C. Further, from the outflow side of the EGR pipe 13 (connection with the intake pipe 11B), EGR gas that has flowed in from the inflow side of the EGR pipe 13 (connection with the exhaust pipe 12B) is discharged into the intake pipe 11B. . Note that the path formed by the EGR pipe 13 through which EGR gas flows corresponds to the EGR path.

The diesel engine 10 (diesel engine) has a plurality of cylinders 45A to 45D, and injectors 43A to 43D are provided in each cylinder. Fuel is supplied to the injectors 43A to 43D via the common rail 41 and fuel pipes 42A to 42D. The injectors 43A to 43D are driven by control signals from the control device 50 and inject fuel into the respective cylinders 45A to 45D.

The diesel engine 10 is provided with a crank angle detection means 22A and a cylinder detection means 22B. The crank angle detection means 22A is, for example, a rotation sensor provided near the crankshaft, and outputs a detection signal corresponding to the rotation angle of the crankshaft of the diesel engine 10 to the control device 50. The cylinder detection means 22B is a rotation sensor provided near the camshaft, and outputs a detection signal to the control device 50 when, for example, the piston of the No. 1 cylinder reaches the compression top dead center. The control device 50 can detect, for example, that the piston of the first cylinder is at the top dead center position based on the detection signal from the crank angle detection means 22A and the detection signal from the cylinder detection means 22B. It is possible to determine whether the dead center position is the compression top dead center position or the intake top dead center position.

Furthermore, the diesel engine 10 is provided with a coolant temperature detection means 28C. The coolant temperature detection means 28C is, for example, a temperature sensor, and detects the temperature of the cooling coolant circulating within the diesel engine 10, and outputs a detection signal according to the detected temperature to the control device 50.

The inflow side of an exhaust manifold 12A is connected to the exhaust side of the diesel engine 10, and the inflow side of an exhaust pipe 12B is connected to the outflow side of the exhaust manifold 12A. The outflow side of the exhaust pipe 12B is connected to the inflow side of the turbine 36, and the outflow side of the turbine 36 is connected to the inflow side of the exhaust pipe 12C.

The inflow side of the EGR pipe 13 is connected to the exhaust pipe 12B. The EGR pipe 13 communicates the exhaust pipe 12B and the intake pipe 11B, and is capable of circulating part of the exhaust gas in the exhaust pipe 12B to the intake pipe 11B. Further, the EGR pipe 13 is provided with an EGR cooler 15 and an EGR valve 14.

The EGR valve 14 (EGR valve) is provided downstream of the EGR cooler 15 in the EGR pipe 13. The EGR valve 14 adjusts the flow rate of EGR gas flowing through the EGR pipe 13 by adjusting the opening degree of the EGR pipe 13 based on a control signal from the control device 50.

EGR cooler 15 is provided in EGR piping 13. The EGR cooler 15 is a so-called heat exchanger, and is supplied with a cooling coolant to cool and discharge EGR gas that has flowed in.

The EGR pipe 13, (EGR cooler 15), and EGR valve 14 constitute an EGR system that can return part of the exhaust gas to the intake path. Note that the EGR system may or may not include the EGR cooler 15.

The outflow side of the exhaust pipe 12B is connected to the inflow side of the turbine 36, and the outflow side of the turbine 36 is connected to the inflow side of the exhaust pipe 12C. The turbine 36 is provided with a variable nozzle 33 that can control the flow rate of the exhaust gas guided to the turbine impeller 36A (the opening degree of the flow path that guides the exhaust gas to the turbine can be adjusted). The opening degree is adjusted by the nozzle driving means 31. The control device 50 outputs a control signal to the nozzle drive means 31 to control the opening of the variable nozzle 33 based on the detection signal from the nozzle opening detection means 32 (for example, a nozzle opening sensor) and the target nozzle opening. Adjustable.

The exhaust pipe 12B on the upstream side of the turbine 36 is provided with a turbine upstream pressure detection means 26A. The turbine upstream pressure detection means 26A is, for example, a pressure sensor, and outputs a detection signal to the control device 50 according to the pressure of exhaust gas in the exhaust pipe 12B on the upstream side of the turbine 36. The exhaust pipe 12C on the downstream side of the turbine 36 is provided with a turbine downstream pressure detection means 26B. The turbine downstream pressure detection means 26B is, for example, a pressure sensor, and outputs a detection signal to the control device 50 in accordance with the pressure of exhaust gas in the exhaust pipe 12C on the downstream side of the turbine 36.

An oxidation catalyst 61 and a particulate filter 62 are provided in the exhaust pipe 12C. Note that a selective reduction catalyst may be provided downstream of the particulate filter 62. Exhaust temperature detection means 28D is provided upstream of the oxidation catalyst 61, and exhaust temperature detection means 28E is provided downstream of the oxidation catalyst 61. The exhaust gas temperature detection means 28D and 28E are, for example, exhaust gas temperature sensors, and output detection signals corresponding to the exhaust gas temperature to the control device 50. Further, the particle collection filter 62 is provided with differential pressure detection means 26C that detects a pressure difference between the upstream side and the downstream side of the particle collection filter 62. The differential pressure detection means 26C is, for example, a pressure sensor, and outputs a detection signal according to the differential pressure between the pressure of the exhaust gas on the upstream side of the particle collection filter 62 and the pressure of the exhaust gas on the downstream side of the particle collection filter 62. Output to the control device 50.

The atmospheric pressure detection means 23 is, for example, an atmospheric pressure sensor, and is provided in the control device 50. The atmospheric pressure detection means 23 outputs a detection signal to the control device 50 according to the atmospheric pressure around the control device 50 .

The vehicle speed detection means 27 is, for example, a vehicle speed detection sensor, and is provided on the wheels of the vehicle. The vehicle speed detection means 27 outputs a detection signal according to the rotational speed of the wheels of the vehicle to the control device 50.

The control device 50 is a fuel property detection device and includes at least a CPU 51 and a storage device 53. As described above, the inputs of the control device 50 (CPU 51) include the intake flow rate detection means 21, the crank angle detection means 22A, the cylinder detection means 22B, the atmospheric pressure detection means 23, the accelerator pedal depression amount detection means 25, and the compressor upstream pressure. Detection means 24A, compressor downstream pressure detection means 24B, intake manifold pressure detection means 24C, turbine upstream pressure detection means 26A, turbine downstream pressure detection means 26B, differential pressure detection means 26C, vehicle speed detection means 27, intake air temperature detection means 28A, 28B. , the coolant temperature detection means 28C, the exhaust temperature detection means 28D and 28E, the nozzle opening detection means 32, the throttle opening detection means 48S, and the like.

Further, the output from the control device 50 (CPU 51) includes control signals to the injectors 43A to 43D, the EGR valve 14, the nozzle driving means 31, the throttle device 48, etc., as described above. Note that the input/output of the control device 50 is not limited to the above-mentioned detection means and actuator. Further, the temperature, pressure, etc. of each part may be calculated by estimation calculation without installing a sensor. The control device 50 detects the operating state and environmental state of the diesel engine 10 based on detection signals from various detection means including the above-mentioned detection means, and controls various actuators including the above-mentioned actuator. The storage device 53 is, for example, a storage device such as a Flash-ROM, and stores programs, data, etc. for controlling the diesel engine 10, performing self-diagnosis, and the like.

The control device 50 (CPU 51) includes a normal multi-stage injection execution unit 51A, an estimated ignition delay time calculation unit 51B, a confirmation single-stage injection execution unit 51C, a torque equivalent amount detection unit 51D, a correction time calculation unit 51E, and an estimated ignition delay time calculation unit 51A. It has a correction section 51F, the details of which will be described later.

● [Multi-stage injection including pilot injection and main injection and estimated ignition delay time (Figure 2)]
FIG. 2 is a diagram showing an example of multistage injection. The horizontal axis shows the crank angle (injection timing is shown in time for convenience), and the vertical axis shows injection execution and heat release rate, respectively. Based on the operating state of the diesel engine 10, the control device 50 controls, for one combustion stroke, a main injection that is the main fuel injection, and one or more fuel injections that are the pre-injection of the main injection. Pilot injection is performed into the cylinders (cylinders 45A to 45D) in which air is compressed and heated. In the description of this embodiment, all injections before the main injection in one combustion stroke are collectively referred to as "pilot injection."

For example, as shown in FIG. 2, in normal multistage injection, the control device 50 executes pilot injections 101A and 102A before main injection 103A to generate pilot combustions 101B and 102B, and then executes main injection 103A. main combustion 103B is generated.

The actual ignition delay time (actual ignition delay time Tr) is from the start time t1 of the main injection 103A to the time t2 when the main combustion 103B starts. On the other hand, the control device 50 operates based on the operating state of the diesel engine 10 (for example, based on detection signals input from the intake air temperature detection means 28A to 28B, the pressure detection means 24A to 24C, the coolant temperature detection means 28C, etc.). ), the estimated ignition delay time Te is calculated. However, the estimated ignition delay time Te calculated in an environment where the intake manifold temperature is low may deviate greatly from the actual ignition delay time Tr. Therefore, the control device 50 corrects (adds) the estimated ignition delay time Te to approach the actual ignition delay time Tr by calculating the correction time Tc, as described below, and corrects the estimated ignition delay time after the correction. Combustion parameters are calculated based on time (Te+Tc).

●[Processing procedure of the overall processing (FIG. 3) in the processing procedure of the first embodiment (FIGS. 3 to 7)]
Next, the processing procedure for calculating the estimated ignition delay time correction time by the control device 50 will be explained using the flowcharts shown in FIGS. 3 to 7. The control device 50 (CPU 51) starts the process shown in FIG. 3, for example, at every predetermined crank angle (for example, every 15 [° CA], see FIG. 8), and advances the process to step S110. For example, the crank angle detection means 22A (see FIG. 1) outputs a detection signal every 15 [°CA] rotation of the crankshaft, and the cylinder detection means 22B detects the position of the No. 1 cylinder just before the compression top dead center position. Output a signal. Each time a detection signal from the crank angle detection means 22A is input, the process shown in FIG. 3 is activated. Note that the confirmation single-stage injection may be executed for any cylinder, but in this embodiment, an example will be described in which the confirmation single-stage injection is executed for the No. 1 cylinder. Further, in this embodiment, an example will be explained in which the ignition timing = P [°CA] is 7 [°CA].

In step S110, the control device 50 updates the value of the crank angle counter (00 to 47 (see FIG. 8)), obtains the time when the current crank angle signal was input, and obtains the value of the crank angle counter (00 to 47 (see FIG. 8)). to 47), and the process proceeds to step S115.

For example, in step S110, the control device 50 initializes the value of the crank angle counter to (00) when the cylinder detection signal from the cylinder detection means 22B (see FIG. 1) is detected (see FIG. 8). If the cylinder detection signal from the cylinder detection means 22B is not detected, the value of the crank angle counter is incremented by 1 (see FIG. 8). As a result, the value of the crank angle counter is updated to one of the values (00 to 47) every 15 [°CA]. For example, a period in which the value of the crank angle counter is (00) indicates that the crank angle is between 0 [°CA] and 15 [°CA] of the compression top dead center of the No. 1 cylinder, and the value of the crank angle counter is The period (24) indicates that the crank angle is between 360 [°CA] and 375 [°CA] of the intake top dead center of the first cylinder.

In step S115, the control device 50 determines whether or not it is the schedule timing for normal multi-stage injection, and if the timing is established (Yes), the process proceeds to step S120, and if the timing is not established (No), the process proceeds to step S125. Proceed with the process. For example, during the period when the value of the crank angle counter is (47), the crank angle is between -15 [°CA] before the compression top dead center of the first cylinder and 0 [°CA] before the compression top dead center. This corresponds to the schedule timing of multi-stage injection. In addition, for example, during the period when the value of the crank angle counter is (11), the crank angle is between 165 [°CA] before the compression top dead center of the No. 3 cylinder and 180 [°CA] at the compression top dead center. , corresponds to the schedule timing of normal multi-stage injection.

When proceeding to step S120, the control device 50 executes process SA000 and proceeds to step S125. Note that the process SA000 is a process that calculates and corrects the estimated ignition delay time, and a process that performs normal multi-stage injection scheduling based on the combustion parameters calculated from the corrected estimated ignition delay time. The details will be described later.

When the process proceeds to step S125, the control device 50 determines whether or not the execution condition of the confirmation single-stage injection is satisfied, and if it is satisfied (Yes), the control device 50 proceeds to the process to step S130, If not (No), the process advances to step S175. The conditions for executing the confirmation single-stage injection are satisfied when the accelerator pedal depression amount is 0 and the fuel is cut during deceleration. For example, the condition for executing the confirmation single-stage injection is satisfied when the foot is removed from the accelerator pedal after accelerating. At this time, the diesel engine 10 is in a state where the rotational speed gradually decreases while rotating by inertia.

When the process proceeds to step S130, the control device 50 determines whether or not the current value of the crank angle counter is (00), and if the current value of the crank angle counter is (00) (Yes). ), the process advances to step S133, and if the current value of the crank angle counter is not (00) (No), the process advances to step S150. In this way, by proceeding to execution of the confirmation single-stage injection when the crank angle counter = 00, the combustion of the confirmation single-stage injection is prevented from continuing, and in this embodiment, only the first cylinder is A single-stage injection is being performed for confirmation.

When the process proceeds to step S133, the control device 50 determines whether or not the confirmation end flag is ON, and if it is not ON (NO), the process proceeds to step S135, and if it is ON (Yes) ) ends the process shown in FIG. The confirmation end flag is a flag that is set to avoid unnecessary injection of confirmation single-stage injection. In other words, after the torque equivalent amount averaging execution condition is satisfied and the average torque equivalent amount is calculated, the execution condition for the confirmation single-stage injection is still satisfied (the diesel engine 10 continues to inertly rotate and the rotation speed increases). If the single-stage confirmation injection continues despite this, it will be a waste of time. Therefore, in such a case, it is temporarily set to ON.

If the process proceeds to step S135, the control device 50 executes process SA200, and then proceeds to step S140. Note that the process SA200 is a process for measuring the rotational speed immediately before executing the confirmation single-stage injection (Ne [immediately], see FIG. 6), and details of the process SA200 will be described later.

In step S140, the control device 50 executes the confirmation single-stage injection, and ends the process shown in FIG. 3. Specifically, the control device 50 drives the injector 43A provided in the cylinder 45A, which is the No. 1 cylinder, using a control signal, and injects a predetermined amount of fuel only through main injection.

When the process proceeds to step S150, the control device 50 determines whether or not the current value of the crank angle counter is (03), and if the current value of the crank angle counter is (03) (Yes) The process advances to step S155, and if the current value of the crank angle counter is not (03) (No), the process advances to step S175.

When proceeding to step S155, control device 50 executes process SA300 and proceeds to step S160. Note that the process SA300 includes a process of measuring the rotational speed immediately after execution of the confirmation single-stage injection (Ne [immediately], see FIG. 3), and a process of measuring the rotational speed immediately before executing the confirmation single-stage injection (Ne [Immediately], see Figure 6)) and the amount of variation in the rotational speed increased by the confirmation single-stage injection (Ne [immediately] - Ne [immediately after]), and the torque equivalent amount is calculated and integrated. , details of processing SA300 will be described later.

In step S160, the control device 50 determines whether or not the torque equivalent amount averaging execution condition is satisfied. If the condition is satisfied (Yes), the process proceeds to step S165, and if the condition is not satisfied ( No), the process advances to step S175. For example, if the torque equivalent amount has been calculated 10 times or more (if the integration counter is greater than or equal to 10), the averaging execution condition is met.

When proceeding to step S165, control device 50 executes process SA400 and proceeds to step S170. Note that the process SA400 is a process for calculating the average torque equivalent amount, and details of the process SA400 will be described later.

When the process proceeds to step S170, the control device 50 sets the confirmation end flag to ON, and ends the process shown in FIG. 3.

When the process proceeds to step S175, the control device 50 sets the confirmation end flag to OFF, and ends the process shown in FIG. 3.

The control device 50 (CPU 51) executing the processes in steps S125 to S140 controls the injector to inject the main injection into the internal combustion engine which is coasting while the rotational speed decreases due to the fuel cut during deceleration. A confirmation single-stage injection execution unit 51C (see FIG. 1) performs a confirmation single-stage injection in which a predetermined amount of fuel is injected with a single-stage injection of only 10 seconds. It corresponds to the confirmation single-stage injection execution unit 51C (see FIG. 1) that executes the confirmation single-stage injection multiple times and consecutively to the internal combustion engine that is rotating due to inertia so as not to cause combustion. ing.

● [Processing procedure of processing SA200 (Figure 4)]
Next, using the flowchart shown in FIG. 4, details of the process SA200 in step S135 in the flowchart shown in FIG. 3 will be described. Process SA200 is a process of measuring Ne [immediately] (see FIG. 8), which is the rotation speed immediately before the confirmation single-stage injection. When the control device 50 executes the process SA200 in step S135 shown in FIG. 3, the control device 50 advances the process to step SA210 shown in FIG.

In step SA210, the control device 50 determines the time when the crank angle signal whose (current) crank angle counter value is (00) is input, and the crank angle signal whose (previous) crank angle counter value is (47). Calculate (measure) Ne [immediately] (see Figure 8), which is the rotation speed immediately before the confirmation single-stage injection, based on the difference (15 [°CA] time) from the time when is input. After completing the process shown in FIG. 4, the process returns, and the process proceeds immediately after step S135 shown in FIG. 3, and the process shown in FIG. 4 ends.

● [Processing procedure of processing SA300 (Figure 5)]
Next, using the flowchart shown in FIG. 5, details of the process SA300 in step S155 in the flowchart shown in FIG. 3 will be described. Processing SA300 includes a process of measuring Ne[immediately] (see FIG. 8), which is the rotation speed immediately after the single-stage confirmation injection, and a process of measuring Ne[immediately] (see FIG. 8), which is the rotation speed immediately after the confirmation single-stage injection, and Ne[immediately] that has already been measured in process SA200. This process calculates and integrates the torque equivalent amount based on the following. When the control device 50 executes the process SA300 in step S155 shown in FIG. 3, the control device 50 advances the process to step SA310 shown in FIG.

In step SA310, the control device 50 determines the time when the crank angle signal whose (current) crank angle counter value is (03) is input, and the crank angle signal whose (previous) crank angle counter value is (02). Calculate Ne [immediately after] (see Figure 8), which is the rotation speed immediately after the combustion generated by the confirmation single-stage injection, based on the difference (time of 15 [°CA]) from the time when is input (see Fig. 8). measurement) and the process proceeds to step SA320.

In step SA320, the control device 50 determines ΔNe, which is the difference between Ne [immediately], which is the rotation speed immediately after the confirmation single-stage injection, and Ne [immediately], which is the rotation speed immediately before the confirmation single-stage injection. (See Figure 8). Then, the control device 50 calculates the torque equivalent amount TQ based on the obtained ΔNe and Ne [immediately], which is the rotation speed immediately before the confirmation single-stage injection, and advances the process to step SA330. Specifically, the control device 50 calculates the torque equivalent amount TQ by multiplying ΔNe and Ne [immediately before]. Therefore, the unit of the torque equivalent amount TQ is rpm^2.

In step SA330, control device 50 adds torque equivalent amount TQ to the integrated value, and advances the process to step SA320. Note that the initial value of the integrated value is set to zero.

In step SA340, control device 50 increments the integration counter and ends the process shown in FIG. 5. Note that the initial value of the integration counter is set to zero.

The control device 50 (CPU 51) executing the processing of steps SA310 to SA320 calculates the rotational speed of the internal combustion engine immediately before executing the confirmation single-stage injection and the amount of variation in the rotational speed increased by the confirmation single-stage injection. This corresponds to the torque equivalent amount detection section 51D (see FIG. 1) that calculates the torque equivalent amount based on .

● [Processing procedure of processing SA400 (Figure 6)]
Next, using the flowchart shown in FIG. 6, details of the process SA400 in step S165 in the flowchart shown in FIG. 3 will be described. Process SA400 is a process for calculating the average torque equivalent amount. When the control device 50 executes the process SA400 in step S165 shown in FIG. 3, the control device 50 advances the process to step SA410 shown in FIG.

In step SA410, control device 50 calculates the average torque equivalent amount TQav based on the integrated value calculated in process SA400 and the integrated counter value, and advances the process to step SA410. For example, if the torque equivalent amount has been calculated 10 times, the cumulative counter value is 10. Therefore, the control device 50 divides the integrated value by 10 to calculate the average torque equivalent amount TQav.

In step SA410, the control device 50 initializes the integrated value and the integrated counter, and ends the process shown in FIG. 5.

The control device 50 (CPU 51) executing the process of step SA410 calculates the torque equivalent amount each time, averages the determined torque equivalent amount, and calculates the torque equivalent amount for calculating the correction time. This corresponds to the torque equivalent amount detection section 51D (see FIG. 1) that calculates the amount of torque.

● [Processing procedure of processing SA000 (Figure 7)]
Next, using the flowchart shown in FIG. 7, details of the process SA000 of step S120 in the flowchart shown in FIG. 3 will be described. The process SA000 is a process of calculating and correcting the estimated ignition delay time, and a process of performing normal multi-stage injection scheduling based on the combustion parameters calculated from the corrected estimated ignition delay time. When the control device 50 executes the process SA000 in step S120 shown in FIG. 3, the control device 50 advances the process to step SA010 shown in FIG.

In step SA010, the control device 50 calculates the estimated ignition delay time based on the detection signals input from, for example, the intake air temperature detection means 28A to 28B, the pressure detection means 24A to 24C, the coolant temperature detection means 28C, etc. The process advances to SA020. Note that the estimated ignition delay time can be determined using an existing calculation method, so a detailed explanation will be omitted.

In step SA020, control device 50 obtains the intake manifold temperature T, and advances the process to step SA030. Note that the control device 50 estimates the intake manifold temperature T based on the detection signals from the intake air temperature detection means 28A and 28B.

In step SA030, control device 50 calculates and updates a correction time according to the combination of average torque equivalent amount TQav and intake manifold temperature T, and proceeds to step SA040. For example, as shown in FIG. 9, the storage device 53 of the control device 50 stores a torque equivalent amount in which a correction time (Δt*) is set according to the average torque equivalent amount (TQ*) and the intake manifold temperature (T*).・Intake manifold temperature and correction time characteristics are memorized. The control device 50 determines a correction time for the estimated ignition delay time based on the torque equivalent amount, intake manifold temperature, and correction time characteristics. Note that the control device 50 obtains the correction time by appropriately supplementing the information. For example, if the calculated average torque equivalent amount is between TQ1 and TQ2 and the intake manifold temperature is T1, the correction time is calculated as the midpoint between Δt11 and Δt21. Note that it is desirable that the initial value of the average torque equivalent amount TQav be set to an appropriate value for each vehicle.

In step SA040, control device 50 adds correction time to the estimated ignition delay time, and advances the process to step SA050. Note that the correction time is changed each time the above-described process SA400 (see FIG. 6) is performed and the average torque equivalent amount is updated.

In step SA050, control device 50 calculates combustion parameters based on the estimated ignition delay time. Note that the combustion parameters can be determined by an existing calculation method based on the estimated ignition delay time, so a detailed explanation will be omitted. The control device 50 drives the injectors 43A to 43D with control signals based on the calculated combustion parameters, and determines the combustion mode, the number of injection stages, the injection amount of each stage, etc. For example, regarding the pilot injection that is injected before the main injection, the timing, amount, and stage of injection are determined.

In step SA060, the control device 50 performs normal multi-stage injection scheduling based on the combustion parameters, and ends the process shown in FIG. 7.

The control device 50 (CPU 51) executing the processing in steps SA010 to SA030 calculates based on the detected torque equivalent amount and the intake air temperature, which is the temperature of the intake manifold of the internal combustion engine or the temperature of the intake air of the internal combustion engine. This corresponds to the correction time calculation unit 51E (see FIG. 1).

The control device 50 (CPU 51) that executes the process of step SA040 corresponds to the estimated ignition delay time correction section 51F (see FIG. 1) that corrects the estimated ignition delay time using the correction time.

The exhaust pipe of the internal combustion engine of the present invention is not limited to the appearance, configuration, structure, etc. described in this embodiment, and various changes, additions, and deletions can be made without changing the gist of the present invention. Further, the numerical values used in the description of this embodiment are merely examples, and the present invention is not limited to these numerical values.

In the description of this embodiment, an example has been described in which the detection signal from the crank angle detection means is output every time the crankshaft rotates by 15 [°CA], but it is limited to every 15 [°CA]. isn't it. Further, although an example has been described in which a signal indicating the compression top dead center position of the first cylinder is output from the cylinder determining means, the present invention is not limited to this. There are various types of crank angle signals and cylinder discrimination signals.

In the description of this embodiment, the ignition timing of the fuel by single-stage confirmation injection is explained as an example of 7 [°CA], but the ignition timing is not limited to this and can be various values. .

In the description of this embodiment, the average torque equivalent amount is calculated after calculating the torque equivalent amount multiple times (10 times), but the torque equivalent amount is calculated only once, and the calculated torque equivalent amount is The correction time may be calculated based on this. Furthermore, even when averaging is performed, the number of calculations is not limited to 10 times, and may be reduced to, for example, 5 times, as long as the accuracy of the corrected estimated ignition delay time calculated based on the average torque equivalent amount can be guaranteed. .

In the description of this embodiment, it is assumed that the confirmation single-stage injection is executed in the No. 1 cylinder, but if the combustion of the confirmation single-stage injection is prevented from continuing, the confirmation single-stage injection can be performed in the other cylinders. Injection may also be performed. Moreover, the confirmation single-stage injection may be performed not only in the same cylinder but also in a plurality of different cylinders.

1 Diesel engine system 10 Diesel engine 11A, 11B Intake pipe 11C Intake manifold 12A Exhaust manifold 12B, 12C Exhaust pipe 13 EGR piping 14 EGR valve 15 EGR cooler 21 Intake flow rate detection means 22A Crank angle detection means 22B Cylinder detection means 23 Atmospheric pressure detection Means 24A Compressor upstream pressure detection means 24B Compressor downstream pressure detection means 24C Intake manifold pressure detection means 25 Accelerator pedal depression amount detection means 26A Turbine upstream pressure detection means 26B Turbine downstream pressure detection means 26C Differential pressure detection means 27 Vehicle speed detection means 28A, 28B Intake air temperature detection means 28C Coolant temperature detection means 28D, 28E Exhaust temperature detection means 30 Turbo supercharger 31 Nozzle drive means 32 Nozzle opening detection means 33 Variable nozzle 35 Compressor 35A Compressor impeller 36 Turbine 36A Turbine impeller 41 Common rail 43A to 43D Injector 45A to 45D Cylinder 48 Throttle device 48S Throttle opening detection means 50 Control device (fuel property detection device)
51 CPU
Tr Actual ignition delay time Te Estimated ignition delay time Tc Correction time

Claims (3)

A control device for a compression self-ignition internal combustion engine that controls an injector that injects fuel into the compression self-ignition internal combustion engine,
The control device includes:
Controlling the injector to perform multi-stage injection including a main injection, which is a main fuel injection, and a pilot injection, which is a fuel injection performed prior to the main injection, for one combustion stroke of the internal combustion engine. A normal multi-stage injection execution unit that performs
Estimating an estimated ignition delay time, which is an estimated value of an ignition delay time, which is a delay time from the start of the main injection until the main combustion occurs, based on the operating state of the internal combustion engine. An ignition delay time calculation section,
For checking that the injector is controlled to inject a predetermined amount of fuel into the internal combustion engine, which is rotating by inertia while the rotation speed decreases due to fuel cut during deceleration, by single-stage injection of only the main injection. a confirmation single-stage injection execution unit that performs single-stage injection;
a torque equivalent amount detection unit that detects a torque equivalent amount corresponding to the torque generated in the internal combustion engine by the confirmation single-stage injection;
Correction for calculating a correction time for correcting the estimated ignition delay time based on the detected torque equivalent amount and an intake air temperature that is the temperature of the intake manifold of the internal combustion engine or the temperature of the intake air of the internal combustion engine. a time calculation section;
an estimated ignition delay time correction unit that corrects the estimated ignition delay time using the correction time;
has,
Control device for compression self-ignition internal combustion engine. A control device for a compression self-ignition internal combustion engine according to claim 1,
The control device includes:
The torque equivalent amount detection unit determines the torque equivalent based on the rotational speed of the internal combustion engine immediately before executing the confirmation single-stage injection and the amount of variation in the rotational speed increased by the confirmation single-stage injection. find the amount,
Control device for compression self-ignition internal combustion engine. A control device for a compression self-ignition internal combustion engine according to claim 1 or 2,
The control device includes:
The confirmation single-stage injection execution unit performs the confirmation single-stage injection multiple times and consecutively on the internal combustion engine that is coasting while the rotation speed decreases due to a fuel cut during deceleration. to avoid combustion,
The torque equivalent amount detection unit determines the torque equivalent amount for each of the plurality of times, and averages the determined torque equivalent amount for the plurality of times to obtain the torque equivalent amount for calculating the correction time. ,
Control device for compression self-ignition internal combustion engine.

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