JP2016079937A - Control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control apparatus capable of raising injection accuracy by determining injection characteristics while raising degrees of freedom of selection of an injector in the case of driving the injector in a partial lift area and a full lift area.SOLUTION: An ECU 28 which is a control apparatus is provided with an injection control part 281 and a characteristic determination part 282. The injection control part 281 executes characteristic control in which, from a state in which a fuel injection amount equal to or less than the total injection amount of fuel is allocated to fuel injection from a port injector 18 and the remaining fuel injection amount of the total injection amount is allocated to fuel injection from an in-cylinder injector 19, the fuel injection amount from the port injector 18 is reduced and the fuel injection amount from the in-cylinder injector 19 is increased according to the reduced fuel injection amount. The characteristic determination part 282 executes characteristic determination for determining injection characteristics of the in-cylinder injector 19 based on an air fuel ratio to be detected according to the characteristic control.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control device for an internal combustion engine having an in-cylinder injector that injects fuel into a cylinder and a port injector that injects fuel into an intake port.

  In recent years, exhaust gas regulations have been strengthened, and a reduction in the minimum fuel injection amount by an injector is required. In order to reduce the minimum injection amount, a technique is known that uses a region (hereinafter also referred to as “partial lift region”) immediately before a region where the injector valve body is completely opened (hereinafter also referred to as “full lift region”). ing. In the partial lift region, the injection characteristics are affected by fluctuations in individual injectors. In order to eliminate this fluctuation effect and ensure an accurate fuel injection amount, the injection characteristics in the partial lift region are learned, and the injection command value is corrected based on the learning result (see Patent Document 1 below). ).

US2003 / 0071613

  In the above-described conventional technology, the injector is controlled according to the required injection amount for normal control, so that the required injection amount may be small or high in many cases, and the injection using the partial lift region is not necessarily performed. Therefore, in some cases, injection in the partial lift region is not performed over a long period of time, and necessary learning may not be performed at a necessary timing.

  Therefore, for example, the required injection amount is divided into the first injection amount using the partial lift region and the remaining second injection amount, thereby increasing the injection frequency in the partial lift region and performing necessary learning. It is possible to do it.

  However, even if the injection frequency (learning frequency) in the partial lift region is increased in this manner, the learning of the injection characteristics in the partial lift region has been made based on the difference from the injection characteristics of the nominal product, so that it can be used. The injector must be compatible with the nominal product, and there is a limit to the degree of freedom of selection.

  The present invention has been made in view of such problems, and its purpose is to determine injection characteristics while increasing the degree of freedom in selecting an injector when the injector is driven in a partial lift region and a full lift region. It is another object of the present invention to provide a control device that can increase the injection accuracy.

  In order to solve the above-described problems, a control device according to the present invention includes an in-cylinder injector (19) for injecting fuel into a cylinder (29) and a port injector (18) for injecting fuel into an intake port (17). A control device (28) for an internal combustion engine (11) having an injection control unit (281) for controlling the fuel injection amount of the in-cylinder injector and the port injector, and an air-fuel ratio sensor (for detecting the air-fuel ratio of the internal combustion engine) 23) and a characteristic determination unit (282) for determining the injection characteristic of the in-cylinder injector based on the air-fuel ratio detected by 23). The injection control unit assigns a fuel injection amount equal to or less than the total fuel injection amount to the fuel injection from the port injector, and assigns the remaining fuel injection amount with respect to the total injection amount to the fuel injection from the in-cylinder injector. The characteristic control unit executes the characteristic control to decrease the fuel injection amount from the cylinder and increase the fuel injection amount from the in-cylinder injector according to the decreased fuel injection amount. The characteristic determination unit is detected according to the execution of the characteristic control. Based on the air-fuel ratio, the characteristic determination for determining the injection characteristic of the in-cylinder injector is executed.

  According to the present invention, air-fuel ratio data acquired by the air-fuel ratio sensor while adjusting in-port injection and in-cylinder injection and adjusting the fuel injection amount from the port injector and the fuel injection amount from the in-cylinder injector. Since the injection accuracy is improved by judging the characteristics of the in-cylinder injector based on the amount of change, the injection accuracy can be improved without setting a nominal product as in the prior art.

  According to the present invention, when the injector is driven in the partial lift region and the full lift region, it is possible to provide a control device that can improve the injection accuracy by determining the injection characteristics while increasing the degree of freedom in selecting the injector. Can do.

It is a figure showing the schematic structure of the engine control system to which ECU (control device) concerning the embodiment of the present invention is applied. It is a block diagram which shows the functional structure of ECU shown in FIG. It is a figure which shows transition of the fuel injection amount at the time of fuel-injecting in a partial lift area | region. It is a figure which shows transition of the fuel injection quantity at the time of fuel injection in a full lift area | region. It is a figure which shows the cumulative injection quantity at the time of making it change from a partial lift area | region to a full lift area | region. It is a flowchart which shows the characteristic judgment flow which determines the boundary of a partial lift area | region and a full lift area | region. FIG. 7 is a diagram illustrating an example of information stored in a storage unit illustrated in FIG. 2 when executing the characteristic determination flow illustrated in FIG. 6. It is a flowchart which shows the characteristic judgment flow which correct | amends the relationship between the electricity supply time in a partial lift area | region, and fuel injection quantity. FIG. 9 is a diagram illustrating an example of information stored in a storage unit illustrated in FIG. 2 when executing the characteristic determination flow illustrated in FIG. 8. It is a figure which shows the relationship map of the energization time and fuel injection amount which are stored in the memory | storage part shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  An engine control system 10 to which an ECU (control device) according to an embodiment of the present invention is applied will be described with reference to FIG. The engine control system 10 includes an engine 11 and an ECU 28, and the ECU 28 controls the behavior of the engine 11.

  The engine 11 will be described. The engine 11 is an internal combustion engine and includes an intake pipe 12, a throttle valve 13, a surge tank 14, an intake manifold 16, an intake port 17, an exhaust pipe 22, and a cylinder 29. In FIG. 1, only one cylinder 29 and a pipe system connected thereto are illustrated, but the engine 11 is an in-line four-cylinder engine having four cylinders 29.

  The intake pipe 12 is provided with a throttle valve 13 whose opening degree is adjusted by a motor (not shown). An air flow meter (not shown) for detecting the intake air amount is provided on the upstream side of the throttle valve 13. A surge tank 14 is provided on the downstream side of the throttle valve 13. An intake pipe pressure sensor 15 that detects the intake pipe pressure is provided on the surge tank 14 or on the downstream side of the surge tank 14. The surge tank 14 is provided with an intake manifold 16 that introduces air into each cylinder of the engine 11.

  The intake manifold 16 is connected to the intake port 17. A port injector 18 for injecting the intake port is attached to the intake port 17. The intake port 17 is connected to each cylinder 29. The intake port 17 is provided with an airflow control valve 20 that controls the airflow strength (the strength of the swirl flow and the tumble flow) in the cylinder 29 (the room defined by the piston 29a and the cylinder 29b, the same applies hereinafter). .

  The cylinder 29 includes a piston 29a and a cylinder 29b. The in-cylinder injector 19 is provided in the cylinder head 29c above the cylinder 29b. The in-cylinder injector 19 is a fuel injection device for in-cylinder injection that directly injects fuel into the cylinder 29. The cylinder head 29 c is provided with a spark plug 21 so as to correspond to each cylinder 29. The in-cylinder mixture of each cylinder 29 is ignited by the spark discharge of the spark plug 21.

  An exhaust pipe 22 is connected to each cylinder 29. The exhaust pipe 22 is provided with an air-fuel ratio sensor 23 for detecting the air-fuel ratio of the exhaust gas. A catalyst (not shown) such as a three-way catalyst for purifying exhaust gas is provided on the downstream side of the air-fuel ratio sensor 23.

  The cylinder block including each cylinder 29 is provided with a coolant temperature sensor 24. A crankshaft 25 is connected to each piston 29a. The crankshaft 25 converts the reciprocating motion of the piston 29a into a circular motion. A crank angle sensor 26 is provided outside the crankshaft 25. The crank angle sensor 26 outputs a pulse signal every time the crankshaft 25 rotates a predetermined crank angle. Based on the output signal of the crank angle sensor 26, the crank angle and the engine speed are detected. The engine control system 10 is provided with an accelerator sensor 27. Based on the output signal from the accelerator sensor 27, the accelerator operation amount (depressed amount of the accelerator pedal) is detected.

  Output signals from the intake pipe pressure sensor 15, the air-fuel ratio sensor 23, the coolant temperature sensor 24, the crank angle sensor 26, and the accelerator sensor 27 are input to the ECU 28. The ECU 28 is mainly composed of a microcomputer, and executes various engine control programs stored in a built-in ROM (storage medium). The ECU 28 outputs control signals to the throttle valve 13, the port injector 18, the in-cylinder injector 19, the airflow control valve 20, and the spark plug 21 in accordance with the execution of this program. As described above, the ECU 28 controls the fuel injection amount, the ignition timing, the throttle opening (intake air amount) and the like according to the engine operating state. At that time, the ECU 28 sets the required injection amounts Qp and Qs of the port injector 18 and the in-cylinder injector 19, the injection timing, and the like according to the engine operating state (for example, the engine speed and load).

  In the present embodiment, the ECU 28 adjusts the required injection amount Qp to the port injector 18 and the required injection amount Qs to the in-cylinder injector 19 while adjusting the air-fuel ratio calculated based on the output signal from the air-fuel ratio sensor 23. The characteristic of the in-cylinder injector 19 is determined based on the fluctuation. A functional configuration of the ECU 28 from this viewpoint will be described with reference to FIG.

  As shown in FIG. 2, the ECU 28 includes an injection control unit 281, a characteristic determination unit 282, and a storage unit 283. Output signals from the air-fuel ratio sensor 23, the crank angle sensor 26, and the accelerator sensor 27 are input to the ECU 28. From these output signals, it is possible to grasp the driving state of the engine 11 (from idling state to normal traveling state, etc.) and the air-fuel ratio.

  The engine control system 10 includes an instruction receiving unit 284 in addition to the above-described components. When the user or maintenance staff operates the instruction receiving unit 284, the ECU 28 executes a flow for determining characteristics of the in-cylinder injector 19 as described later.

  The injection control unit 281 is a functional part that controls the fuel injection amounts of the in-cylinder injector 19 and the port injector 18. The injection control unit 281 outputs a control signal indicating the required injection amount Qp to the port injector 18 and the required injection amount Qs to the in-cylinder injector 19 and stores the information in the storage unit 283.

  The characteristic determination unit 282 is a functional part that determines the injection characteristic of the in-cylinder injector 19 based on the air-fuel ratio detected by the air-fuel ratio sensor 23 that detects the air-fuel ratio of the internal combustion engine. The characteristic determination unit 282 stores the determination result in the storage unit 283. The injection control unit 281 and the characteristic determination unit 282 perform a series of fuel injection control and characteristic determination in conjunction with each other while exchanging their operation information.

  In the present embodiment, the in-cylinder injector 19 is moved to a full lift region (a region where the needle lift amount of the in-cylinder injector 19 becomes the full lift amount) and a partial lift region (a portion before the needle lift amount of the in-cylinder injector 19 becomes the full lift amount). Both areas are used as the partial lift amount).

  As shown in FIG. 3, in the injection pattern F31, the in-cylinder injector 19 is energized so that the energization time is t31. In the energization time t31, the in-cylinder injector 19 becomes a partial lift, so the relationship between the fuel injection amount and the energization time t31 forms a triangle as shown in the figure. Since the fuel injection amount increases little by little with respect to the energization time, the difference in the cumulative injection amount (corresponding to the area of the region surrounded by the diagram) increases when the energization time differs. For example, although the injection pattern F32 shows an example in which the energization time t32 is half of the energization time t31, the area of the triangle that is the cumulative fuel injection amount is considerably less than half. Therefore, the deviation in the energization time results in a large deviation in the cumulative injection amount.

  On the other hand, as shown in FIG. 4, in the fuel injection using the full lift region, the movement profile of the needle returns from the partial lift region to the partial lift region through the full lift region. The fuel injection amount in the full lift region is relatively large with respect to the fuel injection amount in the partial lift region, and there is almost no vertical movement of the fuel injection amount and is constant (region surrounded by a broken line in the figure). The difference in the energization time does not lead to a large shift in the total accumulated injection amount.

  Therefore, it is possible to accurately grasp when fuel injection is performed using only the partial lift region (which is synonymous with accurately grasping the boundary between the partial lift region and the full lift region), and the energization time and fuel injection in the partial lift region. Accurately grasping the relationship with the quantity is necessary for improving the accuracy of fuel injection. Since the relationship between the energization time and the cumulative injection amount is illustrated as shown in FIG. 5, the energization time and the fuel injection amount in the partial lift region are expressed in the assumed line (target value) and the actual line (measured value). Therefore, correction is necessary, and the boundary between the partial lift region and the full lift region (the inflection point surrounded by a broken line) is also shifted, so correction is necessary.

  A flow in which the ECU 28 learns the boundary between the partial lift region and the full lift region of the in-cylinder injector 19 will be described with reference to FIG. In this description, FIG. 7 will be referred to as appropriate. FIG. 7 shows a port injection amount (a fuel injection amount injected from the port injector 18), an in-cylinder injection amount (a fuel injection amount injected from the in-cylinder injector 19), an A / F target value (a target value of the air-fuel ratio). 8 is a table showing an example of A / F current value (actually measured value by air-fuel ratio sensor 23) and A / F change value (difference between A / F target value and A / F current value).

  In step S01, the injection control unit 281 performs control so that all of the total fuel injection amount is injected from the port injector 18 and fuel is not injected from the in-cylinder injector 19. This corresponds to the portion of the table shown in FIG. 7 where “port injection amount” is “100” and “in-cylinder injection amount” is “0”. At this point, “A / F target value” is “14.6”, and “A / F current value” is also “14.6”.

  In step S02 following step S01, the injection control unit 281 performs control so as to decrease the fuel injection amount from the port injector 18 and increase the fuel injection amount from the in-cylinder injector 19. This corresponds to the portion (the right portion in the figure) after the “port injection amount” is “99” and the “in-cylinder injection amount” is “1” in the table shown in FIG. The injection control unit 281 decreases the “port injection amount” by one and increases the “in-cylinder injection amount” by one.

  In step S03 following step S02, the characteristic determination unit 282 reads the air-fuel ratio data output from the air-fuel ratio sensor 23, compares "A / F target value" with "A / F current value", and "A / F change value "is calculated. In the example shown in FIG. 7, when the “port injection amount” is “99” and the “in-cylinder injection amount” is “1”, the “A / F target value” is “14.6” and the “A / F current value”. "Is 14.5", "A / F change value" is "0.1". Thus, the calculation is sequentially performed.

  In step S04 following step S03, the characteristic determination unit 282 determines whether or not the “A / F change value” calculated in step S03 has changed more than a threshold value. In the example shown in FIG. 7, when the “port injection amount” is “99” and “98” and the “in-cylinder injection amount” is “1” and “2”, the “A / F target value” is “14”. .6 ”and“ A / F current value ”is“ 14.5 ”, so“ A / F change value ”is“ 0.1 ”. Subsequently, when the “port injection amount” is “97” and “96” and the “in-cylinder injection amount” is “3” and “4”, the “A / F target value” is both “14.6”. Since the “A / F current value” is “14.4”, the “A / F change value” is “0.2”. Subsequently, when the “port injection amount” is “95” or later and the “in-cylinder injection amount” is “5” or later, the “A / F target value” is “14.6” and the “A / F current value”. "Is" 14.1 "," A / F change value "is" 0.5 ". In the present embodiment, when the “A / F change value” changes from “0.2” to “0.5”, it is determined that there is a large change exceeding the threshold. If it is determined that the “A / F change value” has changed more than the threshold, the process proceeds to step S05. If it is determined that the “A / F change value” has not changed more than the threshold, the process proceeds to step S02. Return.

  In step S05, the characteristic determination unit 282 stores, in the storage unit 283, the previous in-cylinder injection amount that has been determined to have changed significantly beyond the threshold value in step S04, as a boundary between the partial lift region and the full lift region. . In the example shown in FIG. 7, since it was determined that there was a large change exceeding the threshold when the “A / F change value” changed from “0.2” to “0.5”, the “A / F change value” When the “port injection amount” is “96” and the “in-cylinder injection amount” is “4”, that is, the in-cylinder injection amount is “4”. The data is stored in the storage unit 283 as a boundary between the partial lift area and the full lift area.

  Subsequently, a flow in which the ECU 28 corrects the relationship between the energization time and the fuel injection amount in the partial lift region of the in-cylinder injector 19 will be described with reference to FIG. In this description, FIG. 9 will be referred to as appropriate. FIG. 9 shows a port injection amount (a fuel injection amount injected from the port injector 18), an in-cylinder injection amount (a fuel injection amount injected from the in-cylinder injector 19), an A / F target value (a target value of the air-fuel ratio). , A / F current value (actually measured value by air-fuel ratio sensor 23), A / F change value (difference between A / F target value and A / F current value), and in-cylinder injection correction amount is there.

  In step S <b> 21, the injection control unit 281 performs control so that the entire fuel injection amount is injected from the port injector 18 and fuel is not injected from the in-cylinder injector 19. This corresponds to the portion of the table shown in FIG. 7 where “port injection amount” is “100” and “in-cylinder injection amount” is “0”. At this point, “A / F target value” is “14.6”, and “A / F current value” is also “14.6”.

  In step S22 following step S21, the injection control unit 281 performs control so as to decrease the fuel injection amount from the port injector 18 and increase the fuel injection amount from the in-cylinder injector 19. This corresponds to the part (the right part in the figure) after the “port injection amount” in the table shown in FIG. 9 is “99” and the “in-cylinder injection amount” is “1”. The injection control unit 281 decreases the “port injection amount” by one and increases the “in-cylinder injection amount” by one.

  In step S23 following step S22, the characteristic determination unit 282 reads the air-fuel ratio data output from the air-fuel ratio sensor 23, compares "A / F target value" with "A / F current value", and "A / F change value "is calculated. In the example shown in FIG. 9, when “Port injection amount” is “99” and “In-cylinder injection amount” is “1”, “A / F target value” is “14.6” and “A / F current value”. "Is 14.5", "A / F change value" is "0.1". Thus, the calculation is sequentially performed.

  In step S24 following step S23, the characteristic determination unit 282 determines whether or not the “A / F change value” calculated in step S23 has changed more than a threshold value. In the example shown in FIG. 7, when the “port injection amount” is “100” and the “in-cylinder injection amount” is “0”, the “A / F target value” is “14.6” and the “A / F current value”. "Is 14.6", "A / F change value" is "0". Subsequently, when the “port injection amount” is “99” and “98” and the “in-cylinder injection amount” is “1” and “2”, both “A / F target value” is “14.6”. Since “A / F current value” is “14.5”, “A / F change value” is “0.1”. Subsequently, when the “port injection amount” is “97” and “96” and the “in-cylinder injection amount” is “3” and “4”, the “A / F target value” is both “14.6”. Since the “A / F current value” is “14.4”, the “A / F change value” is “0.2”. In the present embodiment, when the “A / F change value” changes from “0” to “0.1”, it is determined that there is a large change exceeding the threshold. If it is determined that the “A / F change value” has changed more than the threshold value, the process proceeds to step S25. If it is determined that the “A / F change value” has not changed more than the threshold value, the process proceeds to step S26. move on.

  In step S25, the characteristic determination unit 282 corrects the map of the fuel injection amount and the energization time in the partial lift region. Like the map illustrated in FIG. 10, the map of the fuel injection amount and the energization time has a different linear relationship depending on the fuel pressure. For example, in the example shown in FIG. 9, when the “port injection amount” is “99” and the “in-cylinder injection amount” is “1”, the “A / F target value” is “14.6” and “A / F Since the “current value” is “14.5”, the “A / F change value” is “0.1”. Since “in-cylinder injection correction amount” for canceling “0.1” of “A / F change value” is “−0.1”, this is dropped into the map illustrated in FIG. Correct so that the fuel injection amount decreases. When the process of step S25 ends, the process returns to step S23.

  In step S26, the characteristic determination unit 282 determines whether correction in the partial lift region has been completed. If the correction in the partial lift area has not been completed, the process returns to step S22, and if the correction in the partial lift area has been completed, the process ends.

  According to the above-described embodiment, the fuel injection amount from the port injector 18 and the fuel injection amount from the in-cylinder injector 19 are adjusted, and based on the change amount of the air-fuel ratio data acquired by the air-fuel ratio sensor 23. Since the injection accuracy is improved by judging the characteristics of the in-cylinder injector 19, the injection accuracy can be improved without setting a nominal product as in the prior art.

  In the present embodiment, the engine 11 has four cylinders 29, and one air-fuel ratio sensor 23 is provided for the four cylinders 29. The injection control unit 281 executes the characteristic control (step S01 and step S02 in FIG. 6, step S21 and step S22 in FIG. 8) described with reference to FIGS. 6 and 8 for each of the four cylinders 29. The characteristic determination unit 282 performs characteristic determination described with reference to FIGS. 6 and 8 for each in-cylinder injector 19 provided in each of the four cylinders 29 (step S03, step S04, and step S05 in FIG. 6, FIG. 8 step S23, step S24, step S25, and step S26) are executed.

  Although the engine 11 is a four-cylinder engine, the present embodiment can be applied to a multi-cylinder engine such as a V-type eight-cylinder engine. In the case of a V-type 8-cylinder engine, one air-fuel ratio sensor 23 may be provided for the four cylinders 29 in one bank, and another air-fuel ratio sensor 23 may be provided for the four cylinders 29 in the other bank. is there. In that case, the injection control unit 281 first executes the characteristic control described with reference to FIGS. 6 and 8 for each of the four cylinders 29 in one bank.

  The characteristic determination unit 282 performs the characteristic determination described with reference to FIGS. 6 and 8 for each in-cylinder injector 19 provided in each of the four cylinders 29 of one bank. In parallel or independently, the injection control unit 281 performs the characteristic control described with reference to FIGS. 6 and 8 for each of the four cylinders 29 in the other bank. In response to this, the characteristic determination unit 282 executes the characteristic determination described with reference to FIGS. 6 and 8 for each in-cylinder injector 19 provided in each of the four cylinders 29 of the other bank.

  As described above, when a plurality of air-fuel ratio sensors 23 are provided, the injection control unit 281 performs characteristic control in parallel for each cylinder 29 to which one air-fuel ratio sensor 23 corresponds, and the characteristic determination unit 282 The characteristic determination is preferably executed for each in-cylinder injector 19 provided in the cylinder 29 for which the characteristic control has been executed. However, it is not essential that the engine 11 has a plurality of cylinders 29. Even if the cylinder 29 is a single cylinder engine, it is possible to execute the characteristic control and characteristic determination of this embodiment. Is possible. If the engine 11 is a single-cylinder engine, the air-fuel ratio sensor 23 corresponds to one cylinder 29. Therefore, it is not necessary to switch the cylinders as described above, and the process is completed with one characteristic control and characteristic determination. can do.

  The characteristic control and characteristic determination described with reference to FIGS. 6 and 8 are preferably in a stable state such as when the engine 11 is idling. This is because it is easy to grasp the relationship between the fuel injection amount and the air-fuel ratio. Therefore, the injection control unit 281 performs characteristic control when the behavior of the engine 11 is in a stable state, and the characteristic determination unit 282 can execute characteristic determination according to the execution of characteristic control by the injection control unit 281. preferable.

  The characteristic control and characteristic determination described with reference to FIGS. 6 and 8 are preferably performed according to the driving state of the engine 11, but it is also preferable that the characteristic control and characteristic determination can be forcibly executed during maintenance. Therefore, in this embodiment, an instruction receiving unit 284 that receives an instruction to execute characteristic control and characteristic determination is provided. When the user or maintenance staff operates the instruction receiving unit 284, an execution instruction signal is transmitted to the ECU 28. The injection control unit 281 performs characteristic control (described with reference to FIGS. 6 and 8) based on the execution instruction from the instruction receiving unit 284, and the characteristic determination unit 282 performs characteristic determination according to the execution of the characteristic control. (Described with reference to FIGS. 6 and 8).

  The characteristic control and characteristic determination described with reference to FIGS. 6 and 8 ensure the accuracy that the fuel injection from the port injector 18 is performed as set or corrected to be set. Preferred above. Therefore, the injection control unit 281 performs preparation control for assigning all the total fuel injection amount to the fuel injection from the port injector 18, and the characteristic determination unit sets the air-fuel ratio detected by the air-fuel ratio sensor 23 according to the preparation control. Based on this, it is preferable to determine the injection characteristic of the port injector 18 and use the result of the determination to correct the characteristic determination.

  The boundary determination for determining the boundary injection amount between the partial lift region and the full lift region of the in-cylinder injector 19 described with reference to FIG. 6 is performed by the injection control unit 281 as described in step S02 of FIG. It is preferable that the “injection amount” is decreased by 1 and the “in-cylinder injection amount” is increased by 1 so that a relationship list as illustrated in FIG. 7 can be acquired at a time. However, the engine 11 suitable for characteristic control and characteristic determination may not be sufficiently driven (for example, idling state).

  In that case, the injection control unit 281 and the characteristic determination unit 282 store the already acquired data in the storage unit 283, and acquire the remaining data to be acquired after the engine 11 is in a driving state suitable for measurement. Is a preferred embodiment. Specifically, when the history of characteristic determination has already been partially recorded in the storage unit 283, the injection control unit 281 uses the port corresponding to the characteristic determination that has already been partially recorded as characteristic control. It is preferable to restart from the fuel injection amount subsequent to the fuel injection amount of the injector 18 and the in-cylinder injector 19, and the characteristic determination unit 282 preferably performs characteristic determination in accordance with the execution of the restarted characteristic control.

  As described above, since the engine 11 suitable for characteristic control and characteristic determination may not be sufficiently driven (for example, idling state), the time required for executing characteristic control and characteristic determination is short. Is preferred. Therefore, when the boundary determination for determining the boundary injection amount between the partial lift region and the full lift region has already been made and the result is stored in the storage unit 283, the next boundary determination is in the vicinity of the boundary injection amount determined last time. It is preferable to start from. Specifically, the injection control unit 281 assigns a fuel injection amount that is a predetermined amount smaller than the boundary injection amount to the in-cylinder injector 19 and assigns the remaining fuel injection amount to the port injector 18. The fuel injection amount from 18 is decreased, and the fuel injection amount from the in-cylinder injector 19 is increased according to the decreased fuel injection amount. The characteristic determination unit 282 performs the characteristic according to the execution of the characteristic control. Make a decision.

  When correcting the relationship between the injection amount and the energization time in the partial lift region of the in-cylinder injector 19 described with reference to FIG. 8, it is preferable that the relationship illustrated in FIG. 9 can be acquired at a time. Is. However, like the boundary determination, the engine 11 suitable for characteristic control and characteristic determination may not be sufficiently driven (for example, idling state).

  In that case, the injection control unit 281 and the characteristic determination unit 282 store the already acquired data in the storage unit 283, and acquire the remaining data to be acquired after the engine 11 is in a driving state suitable for measurement. Is a preferred embodiment. Specifically, when the characteristic determination history (correction value history in the partial lift region) has already been partially recorded in the storage unit 283, the injection control unit 281 has already been recorded as the characteristic control. The characteristic determination unit 282 restarts from the fuel injection amount subsequent to the fuel injection amount of the port injector 18 and the in-cylinder injector 19 corresponding to the determined characteristic determination. preferable.

11: Engine (internal combustion engine)
17: Intake port 18: Port injector 19: In-cylinder injector 23: Air-fuel ratio sensor 28: ECU (control device)
29: Cylinder 281: Injection control unit 282: Characteristic determination unit 283: Storage unit 284: Instruction reception unit

Claims (10)

A control device (28) for an internal combustion engine (11) having an in-cylinder injector (19) for injecting fuel into a cylinder (29) and a port injector (18) for injecting fuel into an intake port (17). ,
An injection control unit (281) for controlling fuel injection amounts of the in-cylinder injector and the port injector;
A characteristic determination unit (282) that determines an injection characteristic of the in-cylinder injector based on an air-fuel ratio detected by an air-fuel ratio sensor (23) that detects an air-fuel ratio of the internal combustion engine;
The injection control unit assigns a fuel injection amount equal to or less than a total fuel injection amount to the fuel injection from the port injector, and assigns a remaining fuel injection amount with respect to the total injection amount to the fuel injection from the in-cylinder injector. The fuel injection amount from the port injector is decreased, and the characteristic control for increasing the fuel injection amount from the in-cylinder injector in accordance with the decreased fuel injection amount is executed.
The control device, wherein the characteristic determination unit executes characteristic determination for determining an injection characteristic of the in-cylinder injector based on an air-fuel ratio detected according to execution of the characteristic control. When a plurality of the air-fuel ratio sensors are provided,
The injection control unit executes the characteristic control in parallel for each of the cylinders corresponding to one air-fuel ratio sensor,
The control device according to claim 1, wherein the characteristic determination unit performs the characteristic determination for each in-cylinder injector provided in the cylinder in which the characteristic control is performed.   The control device according to claim 1 or 2, further comprising a storage unit (283) for storing a history of the characteristic determination.   The said injection control part performs the said characteristic control when the behavior of the said internal combustion engine is a stable state, The said characteristic determination part performs the said characteristic determination according to execution of the said characteristic control. The control device according to any one of 1 to 3. An instruction receiving unit (284) for receiving an instruction to execute the characteristic control and the characteristic determination;
The said injection control part performs the said characteristic control based on the execution instruction from the said instruction | indication reception part, The said characteristic determination part performs the said characteristic determination according to execution of the said characteristic control. Item 4. The control device according to any one of Items 1 to 3. The injection control unit executes preparation control for assigning all the total injection amounts to fuel injection from the port injector,
The characteristic determination unit determines an injection characteristic of the port injector based on an air-fuel ratio detected by the air-fuel ratio sensor in accordance with execution of the preparation control, and uses a result of the determination for correction of the characteristic determination. The control device according to claim 1, wherein:   The control device according to any one of claims 1 to 6, wherein the characteristic determination includes a boundary determination for determining a boundary injection amount between a partial lift region and a full lift region of the in-cylinder injector. The characteristic determination includes a boundary determination for determining a boundary injection amount between a partial lift region and a full lift region of the in-cylinder injector,
When the characteristic determination history has already been recorded in the storage unit,
The injection control unit, as the characteristic control, a fuel injection amount smaller than the boundary injection amount is assigned to the in-cylinder injector, and a residual fuel injection amount is assigned to the port injector. Control to reduce the fuel injection amount from the port injector and increase the fuel injection amount from the in-cylinder injector according to the reduced fuel injection amount;
The control device according to claim 3, wherein the characteristic determination unit executes the characteristic determination according to execution of the characteristic control.   The control device according to claim 1, wherein the characteristic determination includes correction of a relationship between an injection amount in a partial lift region of the in-cylinder injector and an energization time. When a history corresponding to a part of the characteristic determination has already been recorded in the storage unit,
The injection control unit assigns a fuel injection amount to the port injector so as to correspond to a fuel injection amount whose history is not recorded in the storage unit as the characteristic control, and then the fuel injection amount from the port injector. And control to increase the fuel injection amount from the in-cylinder injector according to the decreased fuel injection amount,
The control device according to claim 9, wherein the characteristic determination unit executes the characteristic determination according to execution of the characteristic control.

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