Control device

Abstract

Control device comprising: a control unit (110) configured to supply electrical power to a fuel injector to perform a valve opening actuation to supply fuel to a combustion chamber of an internal combustion engine; a correction unit (130) configured to correct a fuel injection quantity of the fuel injector; and a measuring unit (120) configured to measure, during the execution of the valve opening actuation, a drive current flowing in the fuel injector and / or a drive voltage applied to the fuel injector, wherein a NOx occlusion catalyst (32) is provided in an exhaust pipe of the internal combustion engine to occlude NOx in an exhaust gas flowing through the exhaust pipe in order to reduce and clean occluded NOx, the correction unit being configuredthat it learns the fuel injection quantity of the fuel injector when a NOx purge is performed to reduce and clean the NOx occlusion catalyst; the correction unit is configured to correct the electrical power supplied by the control unit based on a measurement result from the measuring unit in order to correct the fuel injection quantity of the fuel injector; and the correction unit is configured to learn a valve opening time of the fuel injector and / or a valve closing time of the fuel injector based on the drive current and / or the drive voltage in order to learn the fuel injection quantity when the fuel injector performs a partial stroke injection.

Description

Cross-reference to related registration

[0001] This application is based on Japanese patent application no. 2018-230991, which was filed on December 10, 2018. All disclosures of the foregoing applications are incorporated herein by reference. Technical field

[0002] The present disclosure relates to a control device. General state of the art

[0003] An internal combustion engine is equipped with a fuel injector for each cylinder to inject fuel into a combustion chamber. In each fuel injector, a valve body is actuated according to a control signal supplied by a control device to switch between an open and closed state, thereby adjusting the amount of fuel injected. It is known that the amount injected by the fuel injector can vary due to individual differences and deterioration of the fuel injector. In cases where the amount injected varies, exhaust emissions and drivability can deteriorate.Therefore, a control device with a fuel injector as a control object is required to appropriately correct the injection quantity according to the state of each fuel injector and to reduce the variation in the injection quantity.

[0004] For example, a fuel injection control device disclosed in patent document 1 detects a current flowing through a drive coil of the fuel injection valve and adjusts a peak value of the current to a setpoint based on the tendency of a change in the detected current. In this way, the device suppresses an excess or deficiency of the injected quantity. Literature on the state of the art, patent literature

[0005] Patent Literature 1: JP 2017-25803 A Summary of the invention

[0006] The internal combustion engine's temperature is at room temperature immediately after starting. However, after the engine warms up, it gradually rises from a temperature in the transient or unsteady operating state to a temperature in the steady-state operating state. During this time, the temperature of the fuel injector in the engine also rises, causing fluctuations in its electrical properties. For example, the resistance in a fuel injector's drive coil increases as the temperature rises, thus delaying the rise of the current flowing through the drive coil and increasing the time it takes to reach the peak current. In this way, the electromagnetic energy, corresponding to a time integration value of the current flowing through the drive coil, increases, and the applied voltage rises.As a result, the injection quantity may be increased.

[0007] In this context, the fuel injection control device disclosed in patent literature 1 corrects the injection quantity during catalyst warm-up. Therefore, for example, in a lean condition where the temperature is higher than the temperature during warm-up, no suitable correction can be made, and the injection quantity can vary.

[0008] It is an objective of the present disclosure to provide a control device configured to correct the fuel injection quantity of a fuel injector in a lean condition with high accuracy.

[0009] A control device according to one aspect of the present disclosure comprises: a control unit configured to supply electrical power to a fuel injector to perform valve opening control in order to supply fuel to a combustion chamber of an internal combustion engine; and a correction unit configured to correct the fuel injection quantity of the fuel injector. A NOx occlusion or storage catalyst is provided in an exhaust pipe of the internal combustion engine to occlude or store NOx in exhaust gas flowing through the exhaust pipe and to reduce and clean stored NOx. The correction unit is configured to learn the fuel injection quantity of the fuel injector when a NOx purge is performed in order to reduce and clean the NOx occlusion catalyst.

[0010] In the present disclosure, the injection quantity is corrected during driving in a lean condition and during the execution of the NOx scavenging, in which the air-fuel ratio temporarily fluctuates towards a rich-fuel ratio. In other words, the injection quantity is corrected after the internal combustion engine temperature has risen and in a state where combustion is relatively stable. Therefore, the accuracy of the correction in the lean condition is improved compared to the configuration where the injection quantity is corrected, for example, during warm-up or in the stoichiometric condition. List of characters Fig. Figure 1 is an illustration showing a configuration of a vehicle equipped with a control device according to an embodiment of the present disclosure; Fig. 2 is a mapping which function blocks of the in Fig. 1 shows the control device depicted; Fig. Figure 3 is an illustration to explain a full-stroke injection; Fig. Figure 4 is an illustration to explain partial stroke injection; Fig. 5 is a flowchart showing a processing sequence that starts in Fig. The control device shown in 1 is executed; Fig. Figure 6 is a flowchart showing a specific example of an injection quantity correction process; and Fig. Figure 7 is a flowchart showing a specific example of an injection quantity correction process. Description of embodiments

[0011] The present embodiment is described below with reference to the accompanying figures. To facilitate understanding, the same reference numerals have been assigned to the same components in each figure wherever possible, and repetitive explanations have been omitted.

[0012] The control device 100 According to one embodiment of the present disclosure, with reference to Fig. 1 described. The control device 100 It is attached to a part of the vehicle and controls the combustion of fuel.

[0013] The vehicle includes an internal combustion engine. 10 , an inlet or intake pipe 20 , an outlet pipe 30 and a fuel device 40 .

[0014] The internal combustion engine 10 This corresponds to a four-stroke, multi-cylinder internal combustion engine.10 mixes air and liquid fuel in a combustion chamber 11 , to create an air-fuel mixture. A piston 13 is caused by the ignition and combustion of the air-fuel mixture by the ignition of a spark plug 12 powered. The vehicle's driving force is generated by the drive of the piston. 13 generated. The configurations of the cylinders are essentially the same, and therefore one of the cylinders in Fig. 1 is represented as the “internal combustion engine 10”.

[0015] On each cylinder of the internal combustion engine 10 These are various sensors, such as a water temperature sensor. 14 and a crank angle sensor 15 , attached. The water temperature sensor 14 corresponds to a temperature sensor for measuring the temperature of coolant that is located between the radiator (not shown) and the internal combustion engine 10circulates. The crank angle sensor 15 This corresponds to a sensor for measuring the rotation angle of a crankshaft enclosed in a cylinder. The crankshaft angle sensor 15 It also serves as a sensor for measuring machine speed. Each measurement taken by these sensors is fed into the control device. 100 entered.

[0016] The internal combustion engine 10 is equipped with a fuel injector 50 equipped. The fuel injector 50 , which is also referred to as an injector, corresponds to a solenoid valve for injecting fuel into the combustion chamber 11 in the cylinder of the internal combustion engine 10 . The fuel injector 50 Fuel is supplied, which is then pumped by the high-pressure pump described later. 43 is compressed. When the fuel injector opens. 50The fuel is injected from its tip and mixed with air into the combustion chamber. 11 guided. The control device 100 controls the valve opening actuation or the valve opening drive of the fuel injector. 50 to adjust the amount of the combustion chamber 11 to adjust the supplied fuel. The details of the operation of the fuel injector. 50 will be described later.

[0017] The intake manifold 20 corresponds to a line for supplying air to the internal combustion engine 10 The intake pipe 20 is equipped with an airflow meter 21 , a throttle valve or throttle valve 22 and an expansion tank 23 in this order, starting from the upstream side where air is introduced. The internal combustion engine 10is connected to the downstream end of the intake pipe 20 tied together.

[0018] The airflow meter 21 corresponds to a flow meter for measuring the flow rate of an internal combustion engine 10 through the intake pipe 20 supplied air. The reading from the airflow meter 21 The measured flow rate is used in a control device. 100 entered.

[0019] The throttle valve 22 corresponds to a flow rate adjustment valve for adjusting the flow rate through the intake pipe 20 Running air. The degree of throttle valve opening. 22 The airflow rate is adjusted according to the amount of pressure applied to an accelerator pedal (not shown) in the vehicle. 22 is equipped with an opening degree sensor 24 The throttle valve opening degree is provided. 22is done using the opening degree sensor 24 measured and at the control device 100 entered.

[0020] The expansion tank 23 is a box-shaped container located in the middle of the intake pipe 20 is trained. The intake manifold 20 branches out on the downstream side of the expansion tank 23 into several parts, and the branched flow paths are connected to the cylinders accordingly. The inner space of the expansion tank. 23 is larger than the internal space of the other parts of the intake manifold 20 The expansion tank 23 It prevents pressure fluctuations from one cylinder affecting the other cylinders. The expansion tank 23 is equipped with a pressure sensor 25 The intake pressure in the intake line is provided. 20 is connected to the pressure sensor 25 measured and at the control device100 entered.

[0021] The outlet pipe 30 corresponds to a line for delivering a substance to the cylinder of the internal combustion engine. 10 The generated exhaust gas is expelled to the outside. The upstream end of the exhaust pipe 30 is with the internal combustion engine 10 connected. In the middle of the outlet pipe 30 are a three-way catalytic converter 31 and a NOx occlusion catalyst 32 They are provided one after the other for cleaning the exhaust gas.

[0022] The three-way catalytic converter 31 cleans nitrogen oxides (NOx), carbon monoxide (CO) and hydrocarbons (HC) that are present in the exhaust pipe. 30 are contained in the flowing exhaust gas when the air-fuel ratio is close to a stoichiometric state.

[0023] The NOx occlusion catalyst 32The NOx occlusion catalyst occludes or stores NOx contained in the exhaust gas when the air-fuel ratio is lean. 32 It reduces and cleans the stored NOx when the air-fuel ratio is in a relatively rich state, encompassing a stoichiometric or rich condition, and releases the cleaned gas. The operation, in which the fuel injector... 50 The process of temporarily increasing injected fuel when the air-fuel ratio is lean, and adjusting the air-fuel ratio towards a richer mixture to reduce and clean NOx and release the purified gas, is also known as "NOx purging." For example, the control device 100The NOx cleaning control is activated to perform a NOx flush when at least one of the following conditions is met: the NOx storage quantity in the NOx occlusion catalyst 32 is equal to or greater than a predetermined quantity; a requirement arises to change the air-fuel ratio to the stoichiometric state; and the target value of the excess air ratio λ is less than or equal to a predetermined value (that is, the rich fuel state).

[0024] Air-fuel ratio sensors 33 and 34 are located in an upstream section of the three-way catalyst 31 and a section between the three-way catalyst 31 and the NOx occlusion catalyst 32 in the outlet pipe 30 provided. The air-fuel ratio sensors 33 and 34are sensors for measuring the oxygen concentration of the oxygen coming through the outlet pipe 30 running exhaust gas, and the measurement results thereof are taken into account by the control device. 100 entered. The control device 100 controls the injection quantity of the fuel injector. 50 based on the measurement results of the air-fuel ratio sensors 33 and 34 and the like, so that the combustion in the internal combustion engine 10 is carried out with the target air-fuel ratio.

[0025] The fuel device 40 includes a fuel tank 41 , a pump 42 , a high-pressure pump 43 , a pressure storage chamber 44 and a fuel pressure sensor 45 The one in the fuel tank 41 Stored fuel is pumped out by the fuel pump 42, which corresponds to an electromagnetically driven low-pressure pump, is conveyed and fed via the low-pressure line into the high-pressure pump 43 initiated. The one in the high-pressure pump 43 The injected fuel is pumped in the high-pressure pump. 43 compressed and then transferred to the pressure storage chamber 44 The high-pressure fuel, delivered under pressure, is stored in a high-pressure state in the pressure accumulator chamber. 44 stored and then the fuel injector provided in each cylinder 50 supplied.

[0026] The fuel pressure sensor 45 corresponds to a sensor for measuring the fuel pressure in the pressure accumulator chamber 44 The one with the fuel pressure sensor 45 The measured fuel pressure value is used by the control device. 100 entered.

[0027] The control device 100For example, it includes an electronic control unit (ECU: Electronic-Control-Unit) with a microcomputer and performs various controls relating to the internal combustion engine. 10 based on the measured values ​​input from the various sensors, as described above. In addition to the various sensors described above, measured values ​​from a vehicle speed sensor are also used. 61 and an oil temperature sensor 62 at the control device 100 entered. The vehicle speed sensor 61 corresponds to a sensor that measures the vehicle speed of a vehicle on which the control device is located. 100 is mounted, and the vehicle speed is used as a measurement for the control device. 100 outputs. The oil temperature sensor 62 This corresponds to a sensor that measures the oil temperature of the lubricating oil in the internal combustion engine. 10measures and transmits data indicating the oil temperature as a measured value to the control device. 100 outputs. The control device 100 The control device estimates the machine torque and calculates it as an estimated value. 100 measures the battery voltage of a battery (not shown) provided in a vehicle on which the control device is located. 100 is mounted, or receives a measured value of the battery voltage from another control device which has measured the battery voltage in order to obtain the values ​​as a single measured value.

[0028] The control device 100 It calculates a target fuel-air ratio according to the vehicle's operating condition and controls the valve opening of the fuel injector. 50such that the injection quantity approaches the target injection quantity, which fulfills the calculated target fuel-air ratio. The control device 100 adjusts a time period during which the fuel injector 50 is opened, for example by setting a time limit for supplying the fuel injector. 50 is adjusted with electrical power to ensure that the injection quantity matches a predetermined target value.

[0029] However, the relationship between the time the fuel injector is supplied with electrical power and the injection quantity is not constant, and variations can occur due to individual differences, deterioration of the fuel injector, ambient temperature, and the like. This is particularly true in the case of injection where the target injection quantity is very small and where the opening degree of the fuel injector is low. 50 Since the injection quantity does not reach its maximum value, the variation tends to be large. Therefore, to bring the actual injection quantity closer to the target value, it is necessary to correct the injection quantity according to the state of the fuel injector. This correction of the injection quantity is performed by the control device. 100 will be described below.

[0030] Fig. Figure 2 is a diagram showing the input of measured values ​​from the function blocks of the control device. 100 and shows various sensors. As in Fig. The control device shown in section 2 includes the control device. 100 a control unit 110 , a unit of measurement 120 , a correction unit 130 , a fuel pressure control unit 140 , a state determination unit 150 and a storage unit 160 .

[0031] The control unit 110 generates an injection pulse that activates the valve opening actuator and the valve closing actuator of the fuel injector. 50 controls and supplies the fuel injector 50 based on the injection pulse with electrical power to open and close the fuel injector valve 50 to control. In particular, the control unit specifies 110a rectangular drive voltage between a positive terminal P1 and a negative connection P2 on, which is connected to the fuel injector 50 are provided while the injection pulse is active. Upon application of the drive voltage, a drive current flows through the components in the fuel injector. 50 The provided drive coil, and the electromagnetic force generated by the drive current causes the electromagnetic fuel injector to open. 50 The valve opening actuator and the valve closing actuator of the fuel injector. 50 will be with reference to the Fig. 3 and Fig. 4 described in more detail. (A) in Fig. Figure 3 shows an injection pulse that is directed to the fuel injector. 50 is applied. (B) in Fig. Figure 3 shows the stroke amount of the fuel injector. 50 . (C) in Fig. Figure 3 shows the behavior of the fuel injector. 50 . (A) in Fig. Figure 4 shows an injection pulse that is directed to the fuel injector. 50 is applied. (B) in Fig. Figure 4 shows the stroke amount of the fuel injector. 50 . (C) in Fig. Figure 4 shows the behavior of the fuel injector. 50 .

[0032] As in (C) in Fig. As shown in section 3, the fuel injector includes 50 a drive coil 51 , which generates an electromagnetic force when electrical power is supplied, a movable core 52 , which is driven by electromagnetic force, a movable valve body 53 , which is integral with the movable core 52 moved, and an attack 54 , which drives the moving core 52 stops. 51When the injection pulse increases, an electromagnetic force is generated in the drive coil. 51 generated, and the movable core 52 and the valve body 53 are lifted by the electromagnetic force. As a result, the valve body moves. 53 into a valve opening position, so that the fuel injector 50 The cylinder is opened and fuel injection is performed. When the power supply to the drive coil... 51 The valve body is stopped by a falling edge of the injection pulse. 53 pushed back by the spring. As a result, the valve body returns 53 back to a closed position, so that the fuel injector 50 closed and fuel injection is stopped.

[0033] The time (injection pulse width) during which the injection pulse is in the ON state is between the Fig. 3 and Fig. 4 different. If the injection pulse width is sufficiently long, as in (A) in Fig. As shown in section 3, the movable core 52 to the limit 54 and the valve body 53 reaches a full stroke position, as shown in (B) and (C) in Fig. 3 shown. The injection at this time is referred to as a full-stroke injection. If, on the other hand, the injection pulse width is short, as in (A) in Fig. As shown in 4, the movable core 52 only raised to a state before the movable core 52 at the limit 54 triggers, as in (B) and (C) in Fig. 4 shown. Therefore, the valve body reaches 53 The full stroke position is not reached and the injection is in a partial stroke state. Injection at this time is referred to as a partial stroke injection.

[0034] Referring back to Fig. 2 corresponds to the unit of measurement 120a unit that drives the drive coil 51 flowing drive current with a current sensor 70 measures and the one at the negative terminal P2 generated voltage with a voltage sensor 71 measures. The unit of measurement 120 calculates a valve opening time and / or a valve closing time of the fuel injector. 50 based on the measured drive current and / or the measured drive voltage. The valve opening time of the fuel injector. 50 This includes a valve opening start time and a valve opening close time. The valve closing time of the fuel injector. 50 includes a valve closing start time and a valve closing end time.

[0035] In particular, the drive coil 51The flowing drive current gradually decreases after the injection pulse rises. Then the valve opening operation of the fuel injector begins. 50 The current starts when the maximum current value, corresponding to a predetermined setpoint, is reached, or immediately before. Afterwards, the drive current gradually decreases. However, the drive current begins to increase when the fuel injector opens. 50 is complete. It is therefore known that a turning point in the current waveform occurs at this time. Therefore, the measuring unit calculates 120 the valve opening closing time of the fuel injector 50 based on the inflection point generated in the current waveform. The measuring unit 120 For example, the valve opening speed of the fuel injector can be adjusted. 50calculate based on the change in drive current while the fuel injector is operating. 50 The valve opening actuator is executed. Furthermore, the valve opening start time can be calculated based on the calculated valve opening velocity and the valve opening closure time. By measuring the actuator current with the current sensor 70 By measuring in this way, the valve opening start time of the fuel injector can be determined. 50 will be calculated.

[0036] It is known that when the injection pulse is switched off, an induced electromotive force occurs at the negative terminal. P2 is generated when the drive current is forced to drop to 0, and that a turning point in the voltage waveform of the negative terminal P2 occurs. That is, the time corresponds to the inflection point of the voltage waveform of the negative terminal. P2is equal to the time when the valve of the valve body closes 53 is complete. Therefore, the valve closing time of the fuel injector can be determined. 50 by measuring the negative terminal P2 generated voltage using the voltage sensor 71 and calculated by calculating the inflection point generated in the voltage waveform.

[0037] The valve opening start time and the valve closing end time of the fuel injector. 50 , which is from the measuring unit 120 Calculations are performed at the correction unit 130 entered. The unit of measurement 120 can be configured to measure either the drive current or the drive voltage and either the valve opening start time or the valve closing end time at the correction unit 130 enters.

[0038] The correction unit130 This corresponds to a section which adjusts the injection quantity by correcting the power supply to the control unit. 110 to the fuel injector 50 based on the measurement result of the measuring unit 120 corrected. In particular, the correction unit estimates 130 the injection quantity of the fuel injector 50 based on the calculated valve opening start time and / or the calculated valve closing end time. The injection quantity can be estimated by pre-storing, for example, data specifying the relationship between the valve opening start time and the injection quantity of a nominal product in the storage unit. 160 be stored, and that the correction unit 130 refers to the stored data in order to adjust the injection quantity of the fuel injector. 50to estimate. Instead or additionally, data specifying the relationship between the valve closing time and the injection quantity of the nominal product can be pre-stored in the memory unit. 160 be stored, and the correction unit 130 can the injection quantity of the fuel injector 50 estimate by referring to the stored data.

[0039] The correction unit then corrects. 130 the power supply through the control unit 110as needed, so that the difference between the estimated injection quantity and the target injection quantity becomes small. The power supply correction includes, for example, at least one correction of the pulse width of the injection pulse, one correction of the maximum value of the drive voltage applied to the fuel injector, and one correction of the maximum value of the drive current flowing through the drive coil. The correction unit 130 learns the injection quantity by storing the calculated correction value in the storage unit. 160 , while the aforementioned correction is executed repeatedly. The time at which the correction unit 130 The correction of the injection quantity will be described later.

[0040] The fuel pressure control unit 140 corresponds to a section which measures the fuel pressure of the fuel injector 50Fuel supplied based on the use of the fuel pressure sensor 45 The fuel pressure control unit controls the measured fuel pressure. 140 is configured in such a way that it controls the fuel pressure by controlling the high-pressure pump 43 adapts.

[0041] The state determination unit 150 corresponds to a section which determines whether the internal combustion engine 10 in a steady-state operating condition or in a transient / unsteady-state operating condition. The operating state is determined based on a parameter, such as the estimated machine torque measured by the crank angle sensor. 15 entered machine speed, the machine load calculated from the machine speed and the injection quantity, the vehicle speed sensor 61 entered vehicle speed, which is measured by the airflow sensor 21entered intake flow rate, the one from the pressure sensor 25 The input intake pressure corresponds to the required fuel injection quantity. The state determination unit 150 determined that the internal combustion engine 10 The system is in a non-steady operating state if the magnitude or rate of change of at least one of these parameters exceeds a predetermined value. It should be noted that each of the aforementioned parameters may represent a required value rather than the actual measured value.

[0042] The storage unit 160 It stores data that specifies the relationship between at least one parameter from the valve opening start time, the valve closing end time, and the valve opening duration of the nominal product and the injection quantity. The storage unit 160 saves the data from the correction unit 130 calculated correction value.

[0043] The following describes the point in time at which the learning of the injection quantity is carried out in the present embodiment. First, the correction unit learns 130 The injection quantity during driving in lean conditions and during NOx purging is affected. The fuel concentration in lean conditions is lower than in stoichiometric or rich conditions, and therefore high accuracy is required for controlling the fuel injection quantity of the fuel injector. 50 required. Here the internal combustion engine indicates 10 Immediately after starting, the temperature rises to room temperature. In contrast, the temperature rises after the internal combustion engine has warmed up. 10 It gradually increases during the journey. At this time, the resistance value of the drive coil reaches a certain level. 51 of the fuel injector 50with increasing temperature. Therefore, the electromagnetic force decreases due to the reduction of the force through the drive coil. 51 The flowing drive current is weakened, and the injection quantity can be reduced. As described above, the fuel injection quantity is reduced at the fuel injector. 50 affected by temperature.

[0044] In this respect, the correction unit leads 130 In the present embodiment, the learning of the injection quantity is carried out when driving in a lean condition, after the temperature of the internal combustion engine has been reached. 10The learning process takes place when the NOx scavenging process is performed, during which the air-fuel ratio temporarily fluctuates towards the richer fuel side and combustion is stable. Therefore, the learning is carried out under conditions where the ambient temperature is close to that of a lean condition, requiring higher accuracy compared to learning the injection quantity, for example, during warm-up or stoichiometric driving. This allows the injection quantity to be corrected with high accuracy in a lean condition. Furthermore, the injection is used for learning during the NOx scavenging process. Therefore, it is possible to suppress excess fuel injection compared to a configuration where the rich fuel condition is created solely for learning purposes.

[0045] Secondly, it is preferred that the correction unit130 The injection quantity is learned at the time of the partial stroke injection. For example, the control unit divides 110 fuel injection in a cycle of the internal combustion engine 10 and controls the fuel injector 50 such that at least one fuel injection becomes a partial-stroke injection. With partial-stroke injection, the injection quantity at any given time is smaller than with full-stroke injection. Therefore, the required injection quantity in a cycle is achieved by dividing the injection into several injections. The correction unit 130 It learns the injection quantity at the time of the partial-stroke injection among the split injections. When the fuel injector 50 For example, if the full-stroke injection is performed as the first main injection and the partial-stroke injection is performed as the second learning injection, the correction unit learns. 130the injection quantity at the time of the second partial stroke injection.

[0046] In partial-stroke injection, as in Fig. As shown in section 4, the valve body reaches 53 The full-stroke position is not affected. Therefore, the variation in the injection quantity tends to be greater than with full-stroke injection. If the variation in the injection quantity becomes large, exhaust emissions and driving performance can deteriorate. In this respect, the correction unit learns 130 the injection quantity at the time of the partial stroke injection, and therefore the accuracy of the correction of the injection quantity during the partial stroke injection is improved.

[0047] If the fuel injection is split, the control unit 110The injection is controlled so that the first main injection occurs in the first half of the intake stroke and the second learning injection occurs in the second half of the intake stroke or in the second half of the compression stroke. This ensures a predetermined interval between the first and second injections, thus suppressing the influence of the first injection on the second. When the second injection occurs in the second half of the intake stroke, the amount of ejected particulate matter (PN) is reduced compared to when the injection occurs during the compression stroke.If the second injection is carried out in the second half of the compression stroke, the exposed area of ​​the cylinder's side surface at the time of injection is smaller than if the injection is carried out in the first half of the compression stroke, and therefore oil dilution and HC emission caused by fuel adhering to the side surface can be suppressed.

[0048] The method for splitting the fuel injection is not limited to the preceding example. For instance, under high engine load and with a relatively large required injection quantity in a cycle, the main injection can be performed twice, and the learning injection can be performed once. The timing of the injection quantity learning is not limited to the part-stroke injection and can be performed at the time of the full-stroke injection.

[0049] Thirdly, if the operating state corresponds to the non-stationary operating state, the internal combustion engine 10 The amount of NOx emitted is not stable, and therefore there is a concern that an inappropriate correction may be made. If the state determination unit 150 Since the operating state is determined to correspond to the unsteady operating state, it is therefore preferred that the correction unit 130 The injection quantity is not learned. In this way, it is possible to perform a more suitable correction compared to the configuration where learning is carried out in the transient operating state.

[0050] If the correction unit 130 If the control unit performs corrections several times, it may fail. 110These parameters (for example, injection pulse and the like) are set so that the injection duration or injection quantity remains constant with each correction. The fuel pressure control unit 140 can set the fuel pressure, so that the fuel pressure of the fuel that reaches the fuel injector 50 The amount supplied with each injection becomes constant. By setting these parameters, for example, even if the operating state differs at the time of the respective correction, the correction is carried out under essentially the same conditions, and therefore the learning accuracy can be improved.

[0051] When learning the injection quantity of the fuel injector 50 if not completed, the correction unit 130Correct the injection quantity so that, compared to the injection quantity after completion of the learning process, it is on the rich-fuel side. For example, the correction unit can 130 Adjust the initial value of a target air-fuel ratio λ so that it lies within a range on the fat-fuel side in which the air-fuel ratio λ is sufficient from the start of the internal combustion engine. 10This can be done until the injection quantity learning process is complete. In this way, even in a state where the injection quantity learning is incomplete and variation in the injection quantity is likely, sufficient fuel can be ensured, thus stabilizing combustion before learning. Once learning is complete, the fuel concentration can be set relatively lean using the learned result, thereby improving fuel economy. Further reducing the fuel concentration to the lean limit can improve fuel economy even more.

[0052] The following describes the sequence of events controlled by the device. 100 processing carried out with reference to Fig. 5 described. Fig. Figure 5 is a flowchart showing a processing sequence for determining the execution of the injection quantity learning process. The diagram in Fig. The processing sequence shown in Figure 5 can be implemented in the control device. 100 at any time, when a predetermined period of time elapses, and can be executed periodically and repeatedly.

[0053] In the first step S10 It is determined whether the execution condition for performing the injection quantity learning is met or not. In the present embodiment, it is determined that the execution condition is met if all of the following conditions are met: the internal combustion engine 10is not in a non-steady operating state; there is no interruption in the fuel supply; the water temperature and oil temperature are within the predetermined ranges; the fuel pressure is equal to or higher than the predetermined value; the battery voltage is equal to or higher than the predetermined value; the predetermined time interval since the start of the internal combustion engine has elapsed. 10 has elapsed; no anomaly occurs in the on / off valve detection function, in the communications between the ASIC and the microcomputer in the control device 100 If the system is included, no anomaly occurs. For example, by not performing injection quantity learning when the fuel pressure is lower than the predetermined pressure, correction is avoided under conditions where the injection quantity is not stable, and therefore the learning accuracy is improved.

[0054] Each of the parameters, such as water temperature, oil temperature and fuel pressure, under each of the above conditions is measured using the water temperature sensor. 14 , of the oil temperature sensor 62 and the fuel pressure sensor 45 measured and at the control device 100 entered. The learning execution condition is not limited to fulfilling all of the foregoing conditions and may consist of fulfilling some of the conditions.

[0055] If the above execution condition is met (step S11 Yes), the process continues step by step S12 continued. If the above execution condition is not met (step S11 (No), will the in Fig. The processing sequence shown in step 5 is aborted. In this way, the injection quantity is learned when the execution condition is met, and therefore the learning is performed under stable conditions. Furthermore, the learning is performed under essentially the same conditions for each of the multiple fuel injectors, and therefore variations in the fuel injector quantity between cylinders can be suppressed.

[0056] In step S12 It is determined whether the execution condition for performing the NOx purge is met or not. In the present embodiment, it is determined that the NOx purge execution condition is met if at least one of the following conditions is met: the amount of in the NOx occlusion catalyst 32The occluded NOx is equal to or greater than a predetermined amount, a request to change or switch from the lean state to the stoichiometric state occurs, and the target value of the excess air ratio λ is less than or equal to a predetermined value (that is, the fat-fuel side).

[0057] If the above execution condition is met (step S13 Yes), the process continues step by step S14 proceed, and the NOx purge is performed. If the above execution condition is not met (step S11 (No), will the in Fig. The processing sequence shown in step 5 has been completed.

[0058] In step S15 , which is on step S14 The correction unit then corrects 130 the injection quantity, and the process ends.

[0059] The injection quantity is learned by repeatedly performing the aforementioned processing steps periodically. These processing steps are performed for each of the vehicle's multiple cylinders. This means the injection quantity is learned for all fuel injectors. In this way, not only is variation in the injection quantity from one fuel injector to another suppressed, but variation in the injection quantity between different cylinders is also eliminated.

[0060] A specific method for learning the injection quantity in step S15 , as in Fig. 5 is shown with reference to Fig. 6 described. Fig. Figure 6 shows a processing sequence that is executed when the injection quantity is based on the valve closing actuator of the fuel injector. 50is estimated. In this specific example, the correction unit is 130 described as performing the learning at the time of the partial stroke injection.

[0061] As in Fig. As shown in section 6, the measuring unit measures 120 in the first step S20 the voltage of the negative terminal P2 of the fuel injector 50 at the time of the partial stroke injection. The voltage is, for example, generated using an ASIC or a component integrated into the control device. 100 measured the voltage of the negative terminal of the contained microcomputer. P2 to be obtained in chronological order after fuel injection.

[0062] In step S21 , which is on step S20 The unit of measurement is then calculated 120 the inflection point from the waveform of the measured terminal voltage. As described above, this occurs when the fuel injector closes.50 an induced electromotive force is generated, and therefore a turning point occurs in the waveform of the supply voltage.

[0063] In step S22 , which is on step S21 The unit of measurement is then calculated 120 the valve closing point of the fuel injector 50 based on the calculated inflection point. As described above, the time at which the inflection point occurs corresponds to the time at which the valve body 53 returns to the valve closing position.

[0064] In step S23 , which is on step S22 The correction unit then estimates 130 the injection quantity based on the calculated valve closing time of the fuel injector 50 As described above, the injection quantity is determined, for example, by reference to the value stored in the memory unit. 160The stored data of the nominal product was estimated.

[0065] In step S24 , which is on step S23 The correction unit is then calculated 130 the correction amount of the target fuel injector 50 Based on the estimated injection quantity, the system corrects the injection quantity based on the correction amount. This completes the injection quantity correction process.

[0066] It should be noted that the injection quantity estimation method is not limited to the method based on the fuel injector valve closing drive, as described above. For example, the injection quantity can be estimated based on the fuel injector valve opening drive, as described below.

[0067] Fig. Figure 7 shows a processing sequence that is executed when the injection quantity is based on the valve opening drive of the fuel injector. 50 is estimated. In this specific example, it is assumed that the correction unit 130 The learning process takes place during the partial-stroke injection. It should be noted that at the beginning of the valve opening drive, both full-stroke and partial-stroke injection exhibit similar behavior. Therefore, an example method for estimating the injection quantity during partial-stroke injection using the valve opening start time during full-stroke injection is described.

[0068] As in Fig. As shown in 7, the measuring unit measures 120 in the first step S30 at the time of full-stroke injection through the drive coil 51 of the fuel injector 50 flowing drive current.

[0069] In stepS31 , which is on step S30 The unit of measurement is then calculated 120 the inflection point from the waveform of the measured drive current. As described above, the drive current, which has gradually decreased, begins to decrease again at the point where the fuel injector valve closes. 50 to increase, and therefore a turning point occurs in the current waveform.

[0070] In step S32 , which is on step S31 The unit of measurement is then calculated 120 the valve opening closing time of the fuel injector 50 based on the calculated inflection point. As described above, the time at which the inflection point occurs corresponds to the time at which the valve body 53 The full stroke position has been reached.

[0071] In step S33 , which is on step S32 The unit of measurement is then calculated 120The valve opening start time is calculated based on the calculated valve opening end time. The measuring unit 120 For example, the valve opening speed of the fuel injector can be adjusted. 50 calculate based on the change in drive current while the fuel injector is operating. 50 The valve opening actuator is executed. Furthermore, the valve opening start time can be calculated based on the calculated valve opening velocity and the valve opening closure time.

[0072] In step S34 , which is on step S33 The correction unit then estimates 130 the injection quantity during partial-stroke injection based on the calculated valve opening start time during full-stroke injection of the fuel injector 50 As described above, the injection quantity is determined, for example, by reference to the value stored in the memory unit. 160The stored data of the nominal product was estimated.

[0073] In step S35 , which is on step S34 The correction unit is then calculated 130 the correction amount of the target fuel injector 50 Based on the estimated injection quantity, the system corrects the injection quantity based on the correction amount. This completes the injection quantity correction process.

[0074] It should be noted that the injection quantity correction procedure is not based on the one described in the Fig. 6 and Fig. The procedures shown in section 7 are limited. For example, the correction unit 130Calculate both the valve opening start time and the valve closing end time of the fuel injector by combining the above methods and estimate the injection quantity by calculating the valve opening duration of the fuel injector based on the difference between these two times.

[0075] The control device and control method described in the present disclosure can be embodied by one or more special computers equipped with at least one processor and at least one memory, which are programmed to perform one or more functions embodied by a computer program. The control device and control method described in the present disclosure can be embodied by a special computer equipped with at least one processor comprising at least one special hardware logic circuit.The control device and the control method therein, described in the present disclosure, can be embodied by at least one special computer equipped with a combination of a processor and a memory programmed to implement one or more functions, and at least one processor equipped with at least one hardware logic circuit. The computer program can be stored in a tangible, non-transient, computer-readable medium in the form of instructions that can be executed by a computer. The special hardware logic circuit and the hardware logic circuit can be embodied by a digital circuit comprising multiple logic circuits or by an analog circuit.

[0076] The present embodiments have been described with reference to the specific examples above. However, the present disclosure is not limited to these specific examples. Those specific examples which are suitably modified in design by a person skilled in the art also fall within the scope of protection of the present disclosure, provided that the modified examples possess the features of the present disclosure. Each element included in each of the examples described above, as well as the arrangement, state, shape, and the like of each element, are not limited to those illustrated and may be suitably modified. The combinations of elements included in each of the specific examples described above may be suitably modified, provided that no technical inconsistencies arise. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2018230991

[0001] JP 2017025803 A

[0005]

Claims

[1] Control device comprising: a control unit (110) configured to supply electrical power to a fuel injector to perform a valve opening drive to supply fuel to a combustion chamber of an internal combustion engine; and a correction unit (130) which is configured to correct a fuel injection quantity of the fuel injector, wherein a NOx occlusion catalyst (32) is provided in an exhaust pipe of the internal combustion engine to occlude NOx in an exhaust gas flowing through the exhaust pipe in order to reduce and purify occluded NOx, and The correction unit is configured to learn the fuel injection quantity of the fuel injector when a NOx purge is performed to reduce and clean the NOx occlusion catalyst. [2] Control device according to claim 1, further comprising: a measuring unit (120) which is configured to measure a drive current flowing in the fuel injector and / or a drive voltage applied to the fuel injector when the valve opening drive is carried out, wherein The correction unit is configured to correct the electrical power supplied by the control unit based on a measurement result from the measuring unit in order to correct the fuel injection quantity of the fuel injector. [3] Control device according to claim 2, wherein the correction unit is configured to learn a valve opening time of the fuel injector and / or a valve closing time of the fuel injector based on the drive current and / or the drive voltage in order to learn the fuel injection quantity when the fuel injector performs a partial stroke injection. [4] Control device according to claim 3, wherein the control unit is configured such that it divides a fuel injection in a cycle of the internal combustion engine such that at least one of the fuel injections performs the partial stroke injection. [5] Control device according to claim 4, wherein the control unit is configured such that it makes an adjustment such that the partial stroke injection is carried out in a second half of an intake stroke or in a second half of a compression stroke. [6] Control device according to one of claims 3 to 5, wherein the control unit is configured such that it determines an injection duration or the injection quantity during the partial stroke injection used for learning. [7] Control device according to any one of claims 1 to 6, further comprising: a fuel pressure control unit (140) configured to control the fuel pressure of a fuel supplied to the fuel injector, wherein The fuel pressure control unit is configured to set the fuel pressure when the correction unit learns the fuel injection quantity. [8] Control device according to any one of claims 1 to 7, wherein the correction unit is configured such that it does not learn the fuel injection quantity when the fuel pressure of a fuel supplied to the fuel injector is less than a predetermined pressure. [9] Control device according to any one of claims 1 to 8, wherein the correction unit is configured such that, if the learning of the fuel injection quantity of the fuel injector is not completed, it corrects the fuel injection quantity to a rich-fuel side, compared with the fuel injection quantity after completion of the learning. [10] Control device according to any one of claims 1 to 9, further comprising: a state determination unit (150) configured to determine whether the internal combustion engine is in a steady-state operating condition or in a transient operating condition, wherein The correction unit is configured such that it does not learn the fuel injection quantity when the state determination unit determines that the internal combustion engine is in the non-stationary operating state.