JP2007107405A - Fuel injection control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection control device for an internal combustion engine capable of quickly accelerating a vehicle on acceleration request even in the condition that the revolution speed of the internal combustion engine is lower than the rotation speed of an automatic transmission. <P>SOLUTION: When the acceleration request is detected, if a speed difference between the rotation speed of the input shaft of the automatic transmission and the rotation speed of the output shaft of the internal combustion engine is a predetermined value or greater, a fuel injection amount is increased depending on the speed difference. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel injection control device for an internal combustion engine, and more particularly to a fuel injection control device for an internal combustion engine connected to a torque converter type automatic transmission.

In an automobile using an internal combustion engine as a drive device, the vehicle can be accelerated by increasing the amount of fuel injected from the fuel injection device of the internal combustion engine and increasing the output torque of the internal combustion engine. In the fuel injection control device described in Patent Document 1, it is determined whether the vehicle is in the slow acceleration state or the rapid acceleration state from the change in the throttle opening, and the fuel increase corresponding to the acceleration state is performed. According to the description of Patent Document 1, by performing the above control at the time of acceleration, an appropriate amount of fuel can be supplied to the internal combustion engine without a delay in response regardless of whether it is slow acceleration or rapid acceleration. It is said that drivability can be prevented from deteriorating due to attachment.
JP 2004-293154 A JP-A-5-162571

  By the way, in the so-called AT vehicle, an automatic transmission is provided between the internal combustion engine and the drive wheels to automatically change the ratio between the rotation speed of the internal combustion engine (rotation speed per unit time) and the rotation speed of the drive wheels. Yes. In the case of a torque converter type automatic transmission, since the output shaft of the internal combustion engine and the input shaft of the automatic transmission are not directly connected, a rotational speed difference is generated between them. For example, in the “driving state” in which the automatic transmission is driven by the internal combustion engine during acceleration or steady running, the rotational speed of the internal combustion engine is higher than the rotational speed of the automatic transmission. On the other hand, in the “non-drive state” in which the automatic transmission is not driven by the internal combustion engine as during traveling by inertia, the rotational speed of the internal combustion engine is lower than the rotational speed of the automatic transmission.

  When accelerating from the non-driving state, torque is not transmitted to the drive wheels until the rotational speed of the internal combustion engine increases to the rotational speed of the automatic transmission, and acceleration is actually started when the vehicle is driven. It becomes after becoming a state. For this reason, in the acceleration from the non-driving state, the response delay from the acceleration request to the start of acceleration is larger than in the acceleration from the driving state, and there is a possibility that the driver may feel tactile. In order to improve drivability, it is desirable to enable quick acceleration in response to an acceleration request regardless of whether the vehicle is in a driving state or a non-driving state. However, the prior art described in each of the above patent documents does not consider any difference in response delay depending on whether the vehicle is in a driving state or a non-driving state.

  The present invention has been made to solve the above-described problems, and accelerates a vehicle promptly in response to an acceleration request even when the rotational speed of the internal combustion engine is lower than the rotational speed of the automatic transmission. An object of the present invention is to provide a fuel injection control device for an internal combustion engine that enables the above.

In order to achieve the above object, a first invention provides a fuel injection control device for an internal combustion engine connected to a torque converter type automatic transmission.
Basic value calculating means for calculating a basic value of the fuel injection amount based on the operating state of the internal combustion engine;
An acceleration request detecting means for detecting an acceleration request;
A rotational speed difference measuring means for measuring a rotational speed difference between the rotational speed of the input shaft of the automatic transmission and the rotational speed of the output shaft of the internal combustion engine;
An increase value calculating means for calculating an increase value of the fuel injection amount according to the rotation speed difference when the rotation speed difference is greater than or equal to a predetermined value when the acceleration request is detected;
Fuel injection control means for driving an injector to inject fuel of the basic value and the increase value;
It is characterized by having.

According to a second invention, in the first invention,
The injector is a port injector for injecting fuel into an intake port;
When the acceleration request is detected, the fuel injection control means drives the port injector so as to inject fuel for the increased amount by asynchronous injection not synchronized with a crank angle signal.

According to a third invention, in the second invention,
The increase value calculation means predicts a change in the intake air amount after the acceleration request is detected, and calculates the increase value based on the prediction result and the rotation speed difference.

According to a fourth invention, in the first invention,
The injector is an in-cylinder injector that directly injects fuel into the cylinder,
The fuel injection control means drives the in-cylinder injector so as to inject the fuel for the basic value and the fuel for the increased value together by intake stroke injection.

A fifth invention is the fourth invention,
When the difference between the actual intake air amount of the cylinder and the predicted intake air amount used in the calculation of the basic value and the increase value is obtained after the intake stroke is completed or immediately before the intake stroke is completed, and the deviation is equal to or greater than a predetermined value Further includes a correction value calculation means for calculating a correction value of the fuel injection amount based on the deviation and the rotation speed difference,
The fuel injection control means drives the in-cylinder injector so as to inject fuel for the correction value by compression stroke injection.

According to a sixth invention, in the fifth invention,
It further comprises learning correction means for correcting the setting of the increase value with respect to the rotation speed difference by taking the learning value calculated from the correction value into the increase value.

A seventh invention is the invention according to any one of the first to sixth inventions,
It further comprises learning correction means for correcting the setting of the increase value with respect to the rotation speed difference based on the degree of increase in the rotation speed of the input shaft of the automatic transmission.

In order to achieve the above object, an eighth invention includes a port injector for injecting fuel into an intake port and an in-cylinder injector for directly injecting fuel into a cylinder, and a torque converter type automatic transmission In a fuel injection control device for an internal combustion engine connected to
An injection ratio setting means for setting an injection ratio between a fuel injection amount from the port injector and a fuel injection amount from the in-cylinder injector based on an operating state of the internal combustion engine;
An acceleration request detecting means for detecting an acceleration request;
A rotational speed difference measuring means for measuring a rotational speed difference between the rotational speed of the input shaft of the automatic transmission and the rotational speed of the output shaft of the internal combustion engine;
When the acceleration request is detected, if the rotational speed difference is greater than or equal to a predetermined value, the ratio of fuel injection by the port injector is reduced, and the ratio of fuel injection by the in-cylinder injector is increased. Injection ratio correction means for correcting
Fuel injection control means for driving the port injector and the in-cylinder injector based on the determined injection ratio;
It is characterized by having.

  According to the first aspect of the present invention, even if the rotation speed of the input shaft of the automatic transmission is higher than the rotation speed of the output shaft of the internal combustion engine when acceleration is required, the fuel is generated according to the difference in the rotation speed. Since the injection amount is increased, the rotational speed difference is quickly eliminated. As a result, the time lag until torque is transmitted from the internal combustion engine to the automatic transmission is shortened, and the vehicle can be quickly accelerated in response to an acceleration request.

  According to the second aspect of the invention, by using asynchronous injection to inject fuel for the increased value, even in the case of a port injection type internal combustion engine with restrictions on fuel injection timing, the internal combustion engine can be promptly responded to an acceleration request. The rotational speed can be increased and the rotational speed difference can be quickly eliminated.

  According to the third aspect, since the change in the intake air amount after the acceleration request is detected is reflected in the calculation of the increase value, a desired torque can be realized with high air-fuel ratio accuracy, and more reliably. The rotational speed of the internal combustion engine can be increased.

  According to the fourth aspect of the invention, by using the in-cylinder injector that directly injects fuel into the cylinder as the injector, it is possible to reduce the restriction on the fuel injection timing, and the fuel for the increased value and the fuel for the basic value are included. Injection can be performed by intake stroke injection. According to the intake stroke injection, an air-fuel mixture with excellent homogeneity can be obtained, so that not only can the number of revolutions of the internal combustion engine be increased promptly in response to an acceleration request, but also deterioration of exhaust emission can be suppressed. You can also.

  According to the fifth aspect of the invention, when the actual intake air amount exceeds the predicted intake air amount, the intake air amount corresponding to the excess intake air amount is reflected in the correction value of the fuel injection amount. The torque of the internal combustion engine can be increased more reliably.

  According to the sixth aspect of the present invention, by incorporating the learning value calculated from the correction value into the increase value, the proportion of fuel injection by the intake stroke injection excellent in the homogeneity of the air-fuel mixture can be increased by that amount. Emissions can be improved.

  According to the seventh aspect of the invention, the increase in the rotational speed of the automatic transmission after the acceleration request is detected and the fuel injection amount is increased is reflected in the increase value setting, thereby making it possible to deal with individual differences and aging of the internal combustion engine. Regardless, it is possible to obtain an optimal increase value that can eliminate the rotational speed difference in the shortest time.

  Further, according to the eighth invention, when the rotation speed of the input shaft of the automatic transmission is higher than the rotation speed of the output shaft of the internal combustion engine when acceleration is required, there are few restrictions on the fuel injection timing. Since the ratio of in-cylinder injection is increased, the fuel injection amount can be increased early, and the rotational speed of the internal combustion engine can be quickly increased. As a result, the time lag until torque is transmitted from the internal combustion engine to the automatic transmission is shortened, and the vehicle can be quickly accelerated in response to an acceleration request.

Embodiment 1 FIG.
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS.
FIG. 1 is a diagram showing a schematic configuration of a vehicle drive system to which a fuel injection control device according to Embodiment 1 of the present invention is applied. First, the configuration of the drive system according to the present embodiment will be described with reference to FIG.

  The drive system according to the present embodiment includes an internal combustion engine (hereinafter, engine) 2 as a drive device. An automatic transmission 4 is provided between the engine 2 and a drive shaft 6 that transmits engine torque to drive wheels (not shown). The automatic transmission 4 includes a stepped or continuously variable transmission mechanism 4b and an input shaft 4c that inputs rotation to the transmission mechanism 4b. The automatic transmission 4 includes a torque converter 4 a that connects the input shaft 4 c and the output shaft 10 of the engine 2. The rotation of the engine 2 is transmitted from the output shaft 10 to the input shaft 4c via the torque converter 4a, and is transmitted to the drive shaft 6 after being shifted to a desired speed by the speed change mechanism 4b.

  The drive system according to the present embodiment includes an engine speed sensor 42 that outputs a signal corresponding to the engine speed (the speed of the output shaft 10 of the engine 2), and the turbine speed (automatic transmission) of the torque converter 4a. And a turbine rotational speed sensor 44 that outputs a signal corresponding to the rotational speed of the four input shafts 4c). Moreover, the accelerator opening sensor 46 which outputs the signal according to the accelerator opening is provided. The signals of these sensors 42, 44, 46 are input to an ECU (Electronic Control Unit) 40 that comprehensively controls the entire drive system. The ECU 40 controls the operation of the engine 2 and the automatic transmission 4 based on information obtained from signals from the sensors 42, 44, 46 and other information.

  Next, a specific configuration of the engine 2 according to the present embodiment will be described with reference to FIG. The engine 2 according to the present embodiment has a plurality of cylinders (only one cylinder is shown in FIG. 2), and a combustion chamber 12 that repeats expansion and contraction by the vertical movement of the piston 14 is provided inside each cylinder. Is formed. The combustion chamber 12 is connected to an intake passage 16 for supplying air into the combustion chamber 12 and an exhaust passage 18 for discharging combustion gas from the inside. An intake valve 20 for controlling the communication state is provided at a connection portion between the intake passage 16 and the combustion chamber 12, and an exhaust valve 22 for controlling the communication state is provided at a connection portion between the exhaust passage 18 and the combustion chamber 12. Is provided. A throttle valve 34 for adjusting the amount of intake air is disposed in the intake passage 16.

  The engine 2 according to the present embodiment is configured as a dual injector system including two injectors 26 and 28 for each cylinder. One injector 26 is a port injector provided in the intake passage 16, and injects fuel into the intake passage 16, specifically, the intake port. The other injector 26 is an in-cylinder injector provided so that the inside of the combustion chamber 12 faces the cylinder head, and the fuel is directly injected into the combustion chamber 12. A spark plug 24 that ignites the mixed gas in the combustion chamber 12 is attached to the cylinder head of the engine 2.

  As described above, the engine 2 includes various devices for controlling the operation of the engine 2, such as the port injector 26, the in-cylinder injector 28, the throttle valve 34, and the spark plug 24. The ECU 40 operates these devices in accordance with a predetermined control program based on information obtained from the signals of the sensors 42, 44, and 46 described above and other information.

  By the way, in an automobile having a drive system like this embodiment, that is, an AT car, a response delay at the time of acceleration from a non-driving state becomes a problem. This response delay is caused by a time lag until the torque is transmitted from the engine 2 to the automatic transmission 4. Therefore, if this time lag can be shortened, the vehicle is accelerated promptly according to the acceleration request. It becomes possible to make it. As a method for shortening the above time lag, it is conceivable to increase the fuel injection amount to quickly increase the engine speed ne. However, if the fuel increase is too large, there is a risk of generating torque shock or worsening exhaust emissions. In addition, the air-fuel ratio becomes too rich, and there is a risk that the torque will decrease.

  Therefore, in the present invention, when an acceleration request is detected, the fuel injection amount is increased in accordance with the rotational speed difference edlctne (edlctne = nt-ne) between the turbine rotational speed nt and the engine rotational speed ne. According to this, it is possible to quickly increase the engine speed ne to the turbine speed nt without causing torque shock or deterioration of exhaust emission due to excessive fuel increase, and shortening the above time lag. it can.

  In the present embodiment, the port injector 26 is used as a fuel injection device, and an increase in the fuel injection amount corresponding to the rotational speed difference edlctne is realized by fuel injection control of the port injector 26. Hereinafter, fuel injection control during acceleration according to the present embodiment will be described.

  When the port injector 26 is used as a fuel injection device, the fuel injection timing is limited. Specifically, in the intake port injection by the port injector 26, it is necessary to complete the fuel injection before the intake valve 20 is closed. The intake port injection is roughly classified into intake synchronous injection in which fuel is injected during the opening period of the intake valve 20 and intake asynchronous injection in which fuel injection is completed before the intake valve 20 is opened. In order to ensure a sufficient vaporization time, intake asynchronous injection is preferred.

  Thus, in the intake port injection, the fuel injection end timing is important. First, the fuel injection end timing is set, and then the fuel injection start timing is calculated from the fuel injection time and the fuel injection end timing. . The fuel injection time, that is, the drive time of the port injector 26 is determined by the fuel injection amount. The calculation timing of the fuel injection timing and the fuel injection time (fuel injection amount) is larger than the intake stroke so as to always be in time for the start of the fuel injection regardless of whether the intake synchronous injection or the intake asynchronous injection is performed. Is set at the beginning of the exhaust stroke of the previous cycle. This calculation timing is fixed to a constant crank angle, and the calculation is performed in synchronization with the crank angle signal. The fuel injection executed at the fuel injection timing and the fuel injection time calculated at the calculation timing is called synchronous injection.

  In the above-described synchronous injection, a subsequent change in the intake air amount is predicted from the change in the throttle opening, and the fuel injection amount is calculated based on the predicted value. However, in the synchronous injection, the fuel injection amount is calculated at the beginning of the exhaust stroke of the previous cycle, and the fuel injection amount is calculated based on the predicted intake air amount at that time, whereas the actual intake air amount is The final decision is when the intake valve 20 is closed. For this reason, after the calculation of the fuel injection amount, when the throttle opening greatly increases until the intake valve 20 is closed, the actual intake air amount greatly exceeds the predicted intake air amount, and the intake air amount As a result, the fuel injection amount is insufficient. Further, the fuel sucked into the combustion chamber 12 includes the evaporated amount of the attached fuel adhering to the intake port. However, during acceleration, the attached fuel rapidly evaporates due to an increase in the negative pressure of the intake pipe, and the attached fuel. The fuel supply due to evaporation of water will also be interrupted. Therefore, in this case, the air-fuel ratio becomes excessively lean, and the engine 2 cannot output torque according to the throttle opening, resulting in a delay in the increase of the engine speed ne.

  Therefore, when the driver's acceleration request is detected after the calculation of the fuel injection amount for the synchronous injection, the shortage of the fuel injection amount is corrected by executing asynchronous injection not synchronized with the crank angle signal. In this asynchronous injection, the fuel injection amount (fuel injection time) is calculated immediately after the acceleration request is detected. When the fuel injection end timing determined from the fuel injection time is within the valve opening period of the intake valve 20, the port injector 26 of the cylinder is operated to perform additional fuel injection. On the other hand, when the fuel injection end timing does not fall within the valve opening period of the intake valve 20, the port injector 26 of the cylinder that will be in the next intake stroke is operated to perform additional fuel injection.

  In the asynchronous injection described above, the fuel injection amount is calculated based on the deviation between the latest predicted intake air amount at the time when the acceleration request is detected and the predicted intake air amount at the synchronous injection calculation timing. The change in the intake air amount that is predicted when the acceleration request is detected also reflects a sudden change in the throttle opening that accompanies the driver's accelerator operation. Therefore, by calculating the fuel injection amount of asynchronous injection based on the deviation, it is possible to correct the shortage of the fuel injection amount accompanying the increase of the intake air amount.

  In the fuel injection control according to the present embodiment, the difference in speed edlctne between the turbine speed nt and the engine speed ne is reflected in the fuel injection amount (asynchronous injection amount) related to the asynchronous injection. Specifically, the correction coefficient Ktauasy is used to calculate the asynchronous injection amount tauasy, and the correction coefficient Ktauasy is determined from a map having the rotation speed difference edlctne as an axis. FIG. 4 shows an example of a map used for determining the correction coefficient Ktauasy. As shown in this map, the correction coefficient Ktauasy is set to 1 if the rotational speed difference edlctne is 0 or less, and is set to a larger value as the rotational speed difference edlctne becomes larger than 0. Thereby, in the non-driving state where the turbine rotational speed nt is larger than the engine rotational speed ne, the asynchronous injection amount tauasy is increased according to the rotational speed difference edlctne.

  The flowchart of FIG. 3 shows a routine of asynchronous injection performed in the fuel injection control according to the present embodiment. The asynchronous injection according to the present embodiment will be described with reference to this flowchart as follows. The ECU 40 executes the routine shown in FIG. 3 at a constant cycle.

  In the first step 100 of this routine, it is determined whether or not the condition for executing asynchronous injection is satisfied. Here, detection of an acceleration request is set as an execution condition for asynchronous injection. The ECU 40 determines that there is an acceleration request when the change amount or change speed of the accelerator opening measured from the signal of the accelerator opening sensor 46 exceeds a predetermined reference value. When the throttle valve 34 is controlled in conjunction with the accelerator opening, the presence / absence of an acceleration request may be determined from the change amount or change speed of the throttle opening. When the condition for executing asynchronous injection is not satisfied, that is, when there is no acceleration request, the processing of the subsequent steps is skipped.

  When the execution condition for asynchronous injection is satisfied in the determination of step 100, the process of step 102 is executed. In step 102, a cylinder that performs asynchronous injection is set based on the relationship between the acceleration request detection timing and the intake stroke of each cylinder. Specifically, the cylinder that can perform asynchronous injection earliest is set as the injection cylinder. In step 102, the asynchronous injection amount (basic asynchronous injection amount) tauasy is calculated based on the deviation between the latest predicted intake air amount at the acceleration request detection timing and the predicted intake air amount at the synchronous injection calculation timing. The Further, a correction coefficient Ktauasy corresponding to the rotational speed difference edlctne is determined from the map of FIG. 4, and the asynchronous injection amount tauasy is corrected by multiplying the correction coefficient Ktauasy.

  In the next step 104, the asynchronous injection amount tauasy calculated in step 102 is set in the driver of the port injector 26. As a result, when the start timing of asynchronous injection arrives, the fuel of the asynchronous injection amount tauasy increased according to the rotational speed difference edlctne is injected from the port injector 26 to the intake port.

  According to the fuel injection control according to the present embodiment described above, the engine speed difference edlctne is reflected in the asynchronous injection amount tauasy, so that even in the intake port injection where the fuel injection timing is restricted, the acceleration request is met. The speed of the engine 2 can be quickly increased, and the speed difference edlctne can be quickly eliminated. Further, according to the fuel injection control according to the present embodiment, since the change in the intake air amount after the acceleration request is detected is reflected in the calculation of the asynchronous injection amount tauasy, a desired torque is realized with high air-fuel ratio accuracy. It is possible to increase the rotational speed of the engine 2 with certainty.

  In the present embodiment, the ECU 40 calculates the synchronous injection amount, and the basic asynchronous injection amount is calculated when the processing of step 102 is executed, thereby realizing the “basic value calculation means” of the first invention. ing. Further, the processing of step 100 is executed by the ECU 40, thereby realizing the “acceleration request detecting means” of the first invention. Further, when the ECU 40 executes the process of step 102, the basic asynchronous injection amount is multiplied by the correction coefficient Ktauasy corresponding to the rotational speed difference edlctne, and the correction amount (increase) with respect to the basic asynchronous injection amount is calculated. The “increase value calculation means” of the present invention is realized. Further, the “rotational speed difference measuring means” and the “fuel injection control means” of the first invention are also realized as a function of the ECU 40 in the same manner as the above means.

  In addition, the asynchronous injection concerning this embodiment can be implemented also by the routine shown in the flowchart of FIG. The routine shown in FIG. 5 is a modification of the routine shown in FIG. The routine shown in FIG. 5 is characterized in that it is determined whether the vehicle is in a driving state or a non-driving state from the rotational speed difference edlctne, and the execution condition of asynchronous injection is varied according to the determination result.

  In the first step 200 of the routine shown in FIG. 5, it is determined whether the rotational speed difference edlctne is greater than 0, that is, the vehicle is in a non-driving state (edlctne> 0) or a driving state (edlctne ≦ 0). Is determined. As a result of the determination, if the vehicle is in the non-driving state, the determination in step 202 is performed, and if the vehicle is in the driving state, the determination in step 208 is performed.

  In step 202, it is determined whether or not an asynchronous injection execution condition (execution condition 1) is satisfied when the vehicle is in a non-driving state. On the other hand, in step 208, it is determined whether or not an asynchronous injection execution condition (execution condition 2) is satisfied when the vehicle is in a driving state. In both steps 202 and 208, the condition for executing the asynchronous injection is that the acceleration request level exceeds the reference level. However, there is a difference in level between the execution condition 1 and the execution condition 2, and the reference level set in the execution condition 1 is set to a value lower than the reference level set in the execution condition 2. As a result, when the vehicle is in a non-driving state, asynchronous injection is more easily performed than in a driving state. The acceleration request level can be determined from the change amount or change speed of the accelerator opening, or the change amount or change speed of the throttle opening.

  When the vehicle is in a non-driving state and the execution condition 1 of asynchronous injection is satisfied in the determination of step 202, the process of step 204 is executed. In step 204, a cylinder that executes asynchronous injection is set based on the relationship between the timing at which execution condition 1 is satisfied and the intake stroke of each cylinder. Further, in step 204, the asynchronous injection amount tauasy is calculated based on the deviation between the latest predicted intake air amount at the timing when the execution condition 1 is satisfied and the predicted intake air amount at the synchronous injection calculation timing. Further, the asynchronous injection amount tauasy is corrected to a value corresponding to the rotational speed difference edlctne by multiplying by a correction coefficient Ktauasy determined from the rotational speed difference edlctne.

  On the other hand, when the vehicle is in a driving state and the execution condition 2 of asynchronous injection is satisfied in the determination of step 208, the process of step 210 is executed. In step 210, a cylinder that performs asynchronous injection is set based on the relationship between the timing at which execution condition 2 is satisfied and the intake stroke of each cylinder. Further, the asynchronous injection amount tauasy is calculated based on the deviation between the latest predicted intake air amount at the timing when the execution condition 2 is satisfied and the predicted intake air amount at the synchronous injection calculation timing. In this case, the correction of the asynchronous injection amount tauasy according to the rotation speed difference edlctne is not performed.

  In step 206, the asynchronous injection amount tauasy calculated in step 204 or 210 is set in the driver of the port injector 26. Thereby, when the start timing of asynchronous injection arrives, fuel of the asynchronous injection amount tauasy is injected from the port injector 26 to the intake port.

  By changing the execution conditions of asynchronous injection according to the vehicle state as in the above routine and making it easier to execute asynchronous injection than in the driving state in the non-driving state, the acceleration response during acceleration from the non-driving state Can be increased. Further, by setting the execution conditions of asynchronous injection more severely in the driving state than in the non-driving state, it is possible to prevent deterioration of fuel consumption due to frequent use of asynchronous injection.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS.

  As in the first embodiment, the fuel injection control device of the present embodiment is applied to the vehicle drive system having the configuration shown in FIG. 1 and the engine having the configuration shown in FIG. In the first embodiment, the port injector 26 is used as the fuel injection device, and the fuel injection amount increase according to the rotational speed difference edlctne is realized by the fuel injection control of the port injector 26. On the other hand, in the present embodiment, the in-cylinder injector 28 is used as the fuel injection device, and an increase in the fuel injection amount corresponding to the rotational speed difference edlctne is realized by the fuel injection control of the in-cylinder injector 28. Hereinafter, fuel injection control during acceleration according to the present embodiment will be described.

  When the in-cylinder injector 28 is used as a fuel injection device, unlike the port injector 26, there is no restriction on the end timing of fuel injection. Specifically, in the in-cylinder injection by the in-cylinder injector 28, the fuel can be injected not only in the intake stroke but also in the compression stroke after the intake valve 20 is closed. However, when comparing the fuel injection in the intake stroke (intake stroke injection) and the fuel injection in the compression stroke (compression stroke injection), the homogeneity of the air-fuel mixture in the combustion chamber 12 is better in the intake stroke injection, Exhaust emissions are also good. Therefore, when increasing the fuel injection amount in accordance with the rotational speed difference edlctne, it is preferable to supply the increased amount of fuel together with the basic injection amount of fuel to the engine 2 by intake stroke injection.

  However, when the intake stroke injection is executed, the fuel injection amount needs to be calculated before the intake stroke. For this reason, the intake air amount used to calculate the fuel injection amount must be predicted from the change in the throttle opening. If the throttle opening changes and the intake air amount increases after calculating the fuel injection amount, the actual intake air amount will exceed the predicted intake air amount, and the fuel injection amount will be insufficient relative to the intake air amount. Will do.

  In-cylinder injection, compression stroke injection can be used as a means for compensating for a shortage of fuel injection amount in intake stroke injection. When performing the compression stroke injection, the fuel injection amount may be calculated during the period from the late stage of the intake stroke to the early stage of the compression stroke. At this time, the amount of intake air is fixed or almost fixed, so that the amount of fuel shortage can be calculated based on the accurate amount of intake air. The intake air amount can be accurately measured for each cylinder by providing an in-cylinder pressure sensor for each cylinder.

  The flowcharts of FIGS. 6 to 8 show routines executed in the fuel injection control according to the present embodiment. In the routine shown in FIG. 6, the fuel injection timings of the intake stroke injection and the compression stroke injection are determined. In the routine shown in FIG. 7, the fuel injection amount (intake stroke injection amount) etaui related to the intake stroke injection is determined, and in the routine shown in FIG. 8, the fuel injection amount (compression stroke injection amount) etauc related to the compression stroke injection is determined. . The routine shown in FIG. 6 is a main routine that is executed at a constant cycle, and the routines shown in FIGS. 7 and 8 are subroutines that are executed at a predetermined crank angle.

  First, the main routine shown in FIG. 6 will be described. When in-cylinder injection is executed, the fuel injection timing is controlled not by the end timing of fuel injection but by the start timing of fuel injection. In the first step 300, the intake stroke injection start timing (intake stroke injection timing) eainji is calculated based on the operating state of the engine 2 and the like.

  In the next step 302, it is determined whether or not there is an acceleration request. The ECU 40 determines that there is an acceleration request when the change amount or change speed of the accelerator opening measured from the signal of the accelerator opening sensor 46 exceeds a predetermined reference value. When the throttle valve 34 is controlled in conjunction with the accelerator opening, the presence / absence of an acceleration request may be determined from the change amount or change speed of the throttle opening.

  If it is determined that there is an acceleration request, the determination in step 304 is further performed. In step 304, it is determined whether or not the speed difference edlctne (edlctne = nt-ne) between the turbine speed nt and the engine speed ne is greater than 0, that is, the vehicle is in a non-drive state (edlctne> 0) or a drive state ( It is determined which state (edlctne ≦ 0). As a result of the determination, if the vehicle is in a non-driving state, the process proceeds to the next step 306, and the compression stroke injection start timing (compression stroke injection timing) eainjc is calculated based on the operating state of the engine 2 and the like.

  If it is determined in step 302 that there is no acceleration request, or if it is determined in step 304 that the vehicle is in a driving state, the processing in step 306 is skipped. In other words, in the fuel injection control of the present embodiment, the compression stroke injection is executed only when there is an acceleration request and the vehicle is not driven, and in other cases, the intake stroke injection with excellent homogeneity of the air-fuel mixture. Only executed.

  Next, each subroutine shown in FIGS. 7 and 8 will be described. The subroutine shown in FIG. 7 is executed 450 degrees before the ignition TDC (450B). In the first step 310, it is determined whether or not a condition for increasing the fuel injection amount is satisfied. Here, the increase condition is that an acceleration request is detected. The ECU 40 determines whether or not there is an acceleration request from the change amount or change speed of the accelerator opening, or the change amount or change speed of the throttle opening.

  If the increase condition is satisfied in step 310, the process proceeds to step 312, and the intake stroke injection amount etaui is corrected according to the rotational speed difference edlctne. The basic value of the intake stroke injection amount etaui is calculated in advance from the predicted intake air amount, and in step 312, the basic value is multiplied by a correction coefficient corresponding to the rotational speed difference edlctne. The minimum value of the correction coefficient is 1, and the correction coefficient is set to a larger value as the rotational speed difference edlctne is larger. When the increase condition is not satisfied in step 310, the basic value is set as the intake stroke injection amount etaui as it is.

  In the next step 314, the intake stroke injection amount etaui corrected in step 310 or the intake stroke injection amount etaui with the basic value as it is is set in the driver of the in-cylinder injector 28 according to the determination result in step 310. . As a result, when the intake stroke injection timing eainji set in the main routine shown in FIG. 6 arrives, the fuel of the intake stroke injection amount etaui is directly injected into the combustion chamber 10 from the in-cylinder injector 28.

  The subroutine shown in FIG. 8 is executed only when the compression stroke injection timing eainjc is calculated in the main routine shown in FIG. The execution timing of this subroutine is set 180 degrees before the ignition TDC (180B). In the first step 320, it is determined whether or not the fuel injection amount is insufficient. Specifically, the difference between the intake air amount measured at the time of 180B and the intake air amount predicted at the time of 450B is calculated, and if the air amount difference exceeds a predetermined reference value, the fuel It is determined that the injection amount is insufficient. If there is no shortage in the fuel injection amount, it is not necessary to execute the compression stroke injection, so the processing in the subsequent steps is skipped.

  When the fuel injection amount is insufficient, the process proceeds to step 322, and the compression stroke injection amount etauc is calculated. The compression stroke injection amount etauc is calculated based on the air amount difference and the rotation speed difference edlctne. The compression stroke injection amount etauc is set to a larger value as the air amount difference is larger and as the rotational speed difference edlctne is larger.

  In the next step 324, the compression stroke injection amount etauc calculated in step 322 is set in the driver of the in-cylinder injector 28. Thereby, when the compression stroke injection timing eainjc set in the routine shown in FIG. 6 arrives, the fuel of the compression stroke injection amount etauc is directly injected into the combustion chamber 10 from the in-cylinder injector 28.

  According to the fuel injection control according to the present embodiment described above, by using the in-cylinder injector 28 that directly injects fuel into the combustion chamber 10 as a fuel injection device, it is possible to reduce fuel injection timing restrictions. The increased amount of fuel can be injected together with the basic injection amount of fuel by the intake stroke injection. According to the intake stroke injection, an air-fuel mixture with excellent homogeneity can be obtained, so that not only can the number of revolutions of the engine 2 be increased promptly in response to an acceleration request, but also deterioration of exhaust emission can be suppressed. You can also. Further, according to the fuel injection control according to the present embodiment, even when the actual intake air amount exceeds the predicted intake air amount, the fuel injection amount is insufficient due to the increase in the intake air amount by executing the compression stroke injection. Can be corrected. Thereby, a desired torque can be realized with high air-fuel ratio accuracy, and the rotational speed of the engine 2 can be reliably increased.

  In the present embodiment, the ECU 40 calculates the basic value of the intake stroke injection amount etaui, thereby realizing the “basic value calculation means” of the first invention. Further, the “acceleration request detecting means” according to the first aspect of the present invention is realized by executing the processing of step 310 by the ECU 40. Further, by executing the process of step 312 by the ECU 40, the “increase value calculation means” of the first invention is realized, and the subroutine shown in FIG. "Calculation means" is realized. Further, the “rotational speed difference measuring means” and the “fuel injection control means” of the first aspect of the invention are realized as one function of the ECU 40, like the above-described means.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described with reference to FIG.

  As in the first and second embodiments, the fuel injection control device of the present embodiment is applied to the vehicle drive system having the configuration shown in FIG. 1 and the engine having the configuration shown in FIG. In the first and second embodiments, the acceleration responsiveness when accelerating from the non-driving state is increased by increasing the fuel injection amount in accordance with the rotational speed difference edlctne. In the present embodiment, Another method is used to improve acceleration response. Hereinafter, fuel injection control during acceleration according to the present embodiment will be described.

  In the engine 2 having the dual injector system as shown in FIG. 2, the ratio (injection ratio) between the fuel injection amount by the intake port injection using the port injector 26 and the fuel injection amount by the in-cylinder injection using the in-cylinder injector 28. ) Can be changed arbitrarily. The intake port injection has the advantage that a mixture with excellent homogeneity can be obtained as long as the fuel vaporization time can be taken.In-cylinder injection has no restrictions on the fuel injection timing, so it can be quickly performed as needed. There is an advantage that the air-fuel ratio can be adjusted.

  In order to improve the acceleration response when accelerating from the non-driving state, it is necessary to quickly increase the engine speed ne. For this purpose, in-cylinder injection that is more responsive than intake port injection is more suitable as an injection pattern for fuel injection. The flowchart of FIG. 9 shows a routine executed in the fuel injection control according to the present embodiment. In the present embodiment, acceleration response is improved by changing the injection pattern according to the rotational speed difference edlctne by the routine shown in FIG. The ECU 40 executes the routine shown in FIG. 9 at a constant cycle.

  In the first step 400 of the routine shown in FIG. 9, the injection ratio ekpfi is calculated based on the operating state of the engine 2, for example, the engine speed and the intake air amount. In the present embodiment, in parallel with this routine, a routine for calculating the total fuel injection amount from the operating state of the engine 2 is executed. From the total fuel injection amount calculated in this separate routine and the injection ratio ekpfi calculated in this routine, the fuel injection amount of each injector 26, 28 is calculated.

  In the next step 402, it is determined whether or not there is an acceleration request. The ECU 40 determines that there is an acceleration request when the change amount or change speed of the accelerator opening measured from the signal of the accelerator opening sensor 46 exceeds a predetermined reference value. When the throttle valve 34 is controlled in conjunction with the accelerator opening, the presence / absence of an acceleration request may be determined from the change amount or change speed of the throttle opening.

  If it is determined that there is an acceleration request, the determination in step 404 is further performed. In step 404, it is determined whether or not the rotational speed difference edlctne is greater than 0, that is, whether the vehicle is in a non-driving state (edlctne> 0) or a driving state (edlctne ≦ 0). If the result of determination is that the vehicle is in a non-driven state, the routine proceeds to the next step 406, where the injection ratio ekpfi is changed to zero. That is, an injection pattern in which the intake port injection is stopped and only in-cylinder injection is executed is selected.

  If it is determined in step 402 that there is no acceleration request, or if it is determined in step 404 that the vehicle is in a driving state, the processing in step 406 is skipped. That is, in the fuel injection control of the present embodiment, the full in-cylinder injection is forcibly selected only when there is an acceleration request and the vehicle is in the non-driving state, and in other cases, depending on the operating state of the engine 2 The injection pattern selected is selected.

  According to the fuel injection control according to the present embodiment described above, when accelerating from the non-driving state, in-cylinder injection having excellent responsiveness is forcibly selected as the fuel injection injection pattern. The amount can be increased quickly, and the engine speed can be quickly increased. As a result, the time lag until torque is transmitted from the engine 2 to the automatic transmission 4 is shortened, and the vehicle can be quickly accelerated in response to an acceleration request.

  In the present embodiment, the processing of step 400 is executed by the ECU 40, thereby realizing the “injection ratio setting means” of the eighth invention. Further, the processing of step 302 is executed by the ECU 40, whereby the “acceleration request detecting means” of the eighth invention is realized. Further, the processing of step 406 is executed by the ECU 40, whereby the “injection ratio correcting means” of the eighth invention is realized. Further, the “rotational speed difference measuring means” and the “fuel injection control means” according to the eighth aspect of the invention are realized as one function of the ECU 40 in the same manner as the above means.

  In the present embodiment, when accelerating from the non-driving state, the injection ratio ekpfi is set to 0, but it is not necessarily set to 0. Even if the injection ratio ekpfi is set smaller than that during acceleration from the driving state, the effect of increasing the in-cylinder injection ratio can be obtained.

Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described with reference to FIGS.

  According to the fuel injection control according to the second embodiment, when the fuel injection amount in the intake stroke injection is insufficient, the shortage of the fuel injection amount can be corrected by executing the compression stroke injection. However, since the intake stroke injection is superior in the homogeneity of the air-fuel mixture as compared with the compression stroke injection, it is desirable to increase the ratio of the fuel injection amount by the intake stroke injection as much as possible. Therefore, in the fuel injection control according to the present embodiment, the amount of fuel that is regularly additionally injected by the compression stroke injection is learned, and the learned value is taken into the fuel injection amount by the intake stroke injection.

  In the fuel injection control according to the second embodiment, the fuel injection control device of the present embodiment executes the routine shown in FIG. 10 instead of the routine shown in FIG. 7, and shown in FIG. 11 instead of the routine shown in FIG. This can be realized by executing a routine. The routine shown in FIG. 10 is a routine for determining the fuel injection amount (intake stroke injection amount) etaui for the intake stroke injection, and the routine shown in FIG. 11 is the fuel injection amount (compression stroke injection amount) etauc for the compression stroke injection. A routine to determine. Each is a subroutine having the routine shown in FIG. 6 as a main routine, and is executed at a predetermined crank angle.

  The subroutine shown in FIG. 10 is executed 450 ° before ignition TDC (450B). In the first step 330, it is determined whether or not a condition for increasing the fuel injection amount is satisfied. Here, the increase condition is that an acceleration request is detected. The ECU 40 determines whether or not there is an acceleration request from the change amount or change speed of the accelerator opening, or the change amount or change speed of the throttle opening.

  If the increase condition is satisfied in step 330, the process proceeds to step 332, where the intake stroke injection amount etaui is corrected according to the rotational speed difference edlctne. The basic value of the intake stroke injection amount etaui is calculated in advance from the predicted intake air amount. In step 332, the basic value is multiplied by a correction coefficient corresponding to the rotational speed difference edlctne. When the increase condition is not satisfied in step 330, the basic value is set as the intake stroke injection amount etaui as it is.

  In the present embodiment, the process of step 334 is further executed. In step 334, the learning correction amount egtauc is further added to the intake stroke injection amount etaui corrected in accordance with the rotational speed difference edlctne. As the learning correction amount egtauc, a value obtained by multiplying the compression stroke injection amount etauc, for example, a value obtained by integrating a fraction of the compression stroke injection amount etauc or the like can be used. By the process of step 334, the fuel amount that is regularly additionally injected by the compression stroke injection is transferred to the intake stroke injection amount etaui.

  In the next step 336, the intake stroke injection amount etaui learned or corrected in step 334 or the intake stroke injection amount etaui with the basic value as it is is set in the driver of the in-cylinder injector 28 according to the determination result in step 330. The As a result, when the intake stroke injection timing eainji set in the main routine shown in FIG. 6 arrives, the fuel of the intake stroke injection amount etaui is directly injected into the combustion chamber 10 from the in-cylinder injector 28.

  The subroutine shown in FIG. 11 is a routine that is executed only when the compression stroke injection timing eainjc is calculated in the main routine shown in FIG. 6, and the execution timing is set 180 ° before ignition TDC (180B). ing. In the first step 340, it is determined whether or not the fuel injection amount is insufficient from the air amount difference between the intake air amount measured at the time of 180B and the intake air amount predicted at the time of 450B. If there is no shortage in the fuel injection amount, it is not necessary to execute the compression stroke injection, so the processing in the subsequent steps is skipped.

  If the fuel injection amount is insufficient, the process proceeds to step 342, and the compression stroke injection amount etauc is calculated. In the next step 344, the compression stroke injection amount etauc calculated in step 342 is set in the driver of the in-cylinder injector 28. Thereby, when the compression stroke injection timing eainjc set in the routine shown in FIG. 6 arrives, the fuel of the compression stroke injection amount etauc is directly injected into the combustion chamber 10 from the in-cylinder injector 28.

  In the present embodiment, the process of step 346 is further executed. In step 346, the learning correction amount egtauc is updated using the compression stroke injection amount etauc calculated in step 342. The updated learning correction amount egtauc is used for learning correction of the intake stroke injection amount etaui in the process of step 334 at the next execution of the routine shown in FIG.

  According to the fuel injection control according to the present embodiment described above, the learning correction amount egtauc calculated from the compression stroke injection amount etauc is taken into the intake stroke injection amount etaui, and accordingly, the homogeneity of the air-fuel mixture is excellent. The ratio of fuel injection by intake stroke injection can be increased, and exhaust emission can be improved.

  In the present embodiment, the “learning correction means” according to the sixth aspect of the present invention is realized by the ECU 40 executing the processing in step 334 and the processing in step 346.

Embodiment 5. FIG.
Next, Embodiment 5 of the present invention will be described with reference to FIG.

  In the first embodiment, the correction coefficient Ktauasy for correcting the asynchronous injection amount tauasy is determined using the map shown in FIG. In this map, the relationship between the rotational speed difference edlctne and the correction coefficient Ktauasy is defined so that the time lag until the torque is transmitted from the engine 2 to the automatic transmission 4 can be minimized. However, the performance as designed is not always obtained due to individual differences and aging of the engine 2. Therefore, in the fuel injection control according to the present embodiment, the map, that is, the relationship between the rotation speed difference edlctne and the correction coefficient Ktauasy is corrected based on the time lag until the torque is transmitted from the engine 2 to the automatic transmission 4. It was.

  The fuel injection control device of the present embodiment can be realized by executing the routine shown in FIG. 12 together with the routine shown in FIG. 3 in the fuel injection control according to the first embodiment. The routine shown in FIG. 12 is executed at a constant cycle every time the routine shown in FIG. 3 is executed.

  In the first step 110 of the routine shown in FIG. 12, the cylinder number of the cylinder in which asynchronous injection is executed by the routine shown in FIG. 3, that is, the cylinder set as the injection cylinder in step 102 is stored.

  In the next step 112, it is determined whether or not there is an asynchronous injection execution history. This execution history is written in the memory of the ECU 40 when asynchronous injection is executed by the routine shown in FIG. 3, and is erased when torque is transmitted from the engine 2 to the automatic transmission 4 and the purpose of asynchronous injection is achieved. It has come to be. When there is no asynchronous injection execution history, this routine ends.

  If there is an execution history of asynchronous injection, the determination in step 114 is performed. In step 114, it is determined whether or not the current turbine rotational speed nt is higher than the previous turbine rotational speed ntold by more than the determination value α. The turbine rotational speed nt increases when the engine rotational speed ne increases and torque is transmitted from the engine 2 to the automatic transmission 4. The determination value α is set to a value that can clearly determine that the turbine rotational speed nt has increased even when the variation of the turbine rotational speed nt is taken into consideration.

  When the current value nt is not higher than the previous value ntold beyond the determination value α, it can be determined that torque is not yet transmitted from the engine 2 to the automatic transmission 4. In that case, the routine proceeds to step 116 where the counter A is incremented. Note that the initial value of the counter A is 0.

  When the current value nt is higher than the previous value ntold by exceeding the determination value α, it can be determined that torque is transmitted from the engine 2 to the automatic transmission 4 and the turbine speed nt has risen. In that case, the process proceeds to step 118 and it is determined whether or not the counter A is within the reference value B. The value of the counter A indicates a delay time from when the asynchronous injection is executed until the turbine rotational speed nt rises. On the other hand, the reference value B indicates the maximum allowable delay time.

  If the counter A is within the reference value B, it can be determined that the torque has been quickly transmitted from the engine 2 to the automatic transmission 4 as designed by executing asynchronous injection. Therefore, it can be determined that the current asynchronous injection amount tauasy is an appropriate amount, and it is not necessary to correct the relationship between the rotation speed difference edlctne and the correction coefficient Ktauasy in the map. In this case, the counter A is cleared by the process of step 120, and after the execution history of the asynchronous injection is deleted by the process of step 122, this routine ends.

  If the result of determination in step 118 is that the counter A exceeds the reference value B, it can be determined that the increase in the engine speed ne is delayed from the design due to insufficient torque of the engine 2. The output torque of the engine 2 decreases even if the air-fuel ratio is too lean or excessively rich. Therefore, if the counter A exceeds the reference value B, it is determined in the next step 124 whether the air-fuel ratio is richer or leaner than the appropriate air-fuel ratio. The air / fuel ratio can be measured by disposing an air / fuel ratio sensor in the exhaust passage 18.

  If the air-fuel ratio is richer than the appropriate air-fuel ratio, the process of step 126 is performed. In step 126, the relationship between the rotational speed difference edlctne and the correction coefficient Ktauasy in the map is corrected so as to reduce the asynchronous injection amount tauasy. On the other hand, if the air-fuel ratio is leaner than the appropriate air-fuel ratio, the process of step 128 is performed. In step 128, the relationship between the rotational speed difference edlctne and the correction coefficient Ktauasy in the map is corrected so as to increase the asynchronous injection amount tauasy. Since a map is prepared for each cylinder, the map correction performed in step 126 or 128 is performed only for the cylinder for which asynchronous injection has been executed, that is, the cylinder of the cylinder number stored in step 110. The

  When the map is corrected by the processing of step 126 or step 128, the proper amount of asynchronous injection amount tauasy capable of realizing the appropriate air-fuel ratio is injected from the port injector 26 at the next asynchronous injection of the cylinder. After execution of step 126 or step 128, the counter A is cleared by the process of step 120, and the execution history of asynchronous injection is deleted by the process of step 122.

  According to the fuel injection control according to the present embodiment as described above, the delay time from when the asynchronous injection is executed until the turbine rotational speed nt rises is reflected in the setting of the asynchronous injection amount tauasy. It is possible to obtain the optimum asynchronous injection amount tauasy that can minimize the time lag until the torque is transmitted from the engine 2 to the automatic transmission 4 regardless of aging.

  In the present embodiment, the “learning correction means” according to the seventh aspect of the present invention is realized by the ECU 40 executing the above routine.

Others.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the following modifications may be made.

  The fuel injection control according to the first embodiment and the fuel injection control according to the fifth embodiment can be applied to an engine having only a port injector. The fuel injection control according to the second embodiment and the fuel injection control according to the fourth embodiment can also be applied to an engine having only an in-cylinder injector.

  The learning correction of the asynchronous injection amount tauasy carried out in the fifth embodiment, that is, the technique for reflecting the delay time from when the asynchronous injection is executed until the turbine rotational speed nt rises to the setting of the asynchronous injection amount tauasy is implemented. The fuel injection control according to the second embodiment, that is, the fuel injection control using in-cylinder injection can also be applied. In this case, the delay time from when the intake stroke injection amount etaui is increased to when the turbine speed nt rises may be reflected in the setting of the increase value of the intake stroke injection amount etaui.

  In the first and second embodiments, the fuel injection amount is increased when the rotational speed difference edlctne is greater than 0, that is, in the non-driven state. When the rotational speed difference edlctne is small, the fuel injection amount may not be increased, and the fuel injection amount may be increased if the rotational speed difference edlctne is equal to or greater than a predetermined value greater than zero. The same applies to the third embodiment, and even in the non-driven state, if the rotational speed difference edlctne is small, the injection ratio ekpfi is not reduced, and if the rotational speed difference edlctne is greater than a predetermined value greater than 0, the injection ratio You may make ekpfi small.

It is a figure which shows schematic structure of the drive system of the vehicle to which the fuel-injection control apparatus as Embodiment 1 of this invention is applied. It is a figure which shows the specific structure of the engine to which the fuel-injection control apparatus as Embodiment 1 of this invention was applied. It is a flowchart of the asynchronous injection routine performed in Embodiment 1 of this invention. It is a figure which shows the map used for determination of the correction coefficient Ktauasy for correct | amending asynchronous injection quantity tauasy according to rotation speed difference edlctne. It is a flowchart of the modification of the asynchronous injection routine performed in Embodiment 1 of this invention. It is a flowchart of the injection timing calculation routine performed in Embodiment 2 of the present invention. It is a flowchart of the intake stroke injection amount calculation routine executed in the second embodiment of the present invention. It is a flowchart of the compression stroke injection amount calculation routine executed in the second embodiment of the present invention. It is a flowchart of the injection pattern selection routine performed in Embodiment 3 of the present invention. It is a flowchart of the intake stroke injection amount calculation routine executed in the fourth embodiment of the present invention. It is a flowchart of the compression stroke injection amount calculation routine executed in the fourth embodiment of the present invention. It is a flowchart of the asynchronous injection amount learning routine performed in Embodiment 5 of the present invention.

Explanation of symbols

2 Engine 4 Automatic transmission 4a Torque converter 4b Transmission mechanism 4c Automatic transmission input shaft 6 Drive shaft 10 Engine output shaft 12 Combustion chamber 16 Intake passage 20 Intake valve 22 Exhaust valve 26 Port injector 28 In-cylinder injector 34 Throttle valve 40 ECU
42 Engine speed sensor 44 Turbine speed sensor 46 Accelerator opening sensor

Claims (8)

In a fuel injection control device for an internal combustion engine connected to a torque converter type automatic transmission,
Basic value calculating means for calculating a basic value of the fuel injection amount based on the operating state of the internal combustion engine;
An acceleration request detecting means for detecting an acceleration request;
A rotational speed difference measuring means for measuring a rotational speed difference between the rotational speed of the input shaft of the automatic transmission and the rotational speed of the output shaft of the internal combustion engine;
An increase value calculating means for calculating an increase value of the fuel injection amount according to the rotation speed difference when the rotation speed difference is greater than or equal to a predetermined value when the acceleration request is detected;
Fuel injection control means for driving an injector to inject fuel of the basic value and the increase value;
A fuel injection control device for an internal combustion engine, comprising: The injector is a port injector for injecting fuel into an intake port;
2. The fuel injector according to claim 1, wherein when the acceleration request is detected, the port injector is driven so as to inject fuel corresponding to the increased value by asynchronous injection not synchronized with a crank angle signal. A fuel injection control device for an internal combustion engine as described.   The increase value calculation means predicts a change in the intake air amount after the acceleration request is detected, and calculates the increase value based on the prediction result and the rotation speed difference. Item 3. A fuel injection control device for an internal combustion engine according to Item 2. The injector is an in-cylinder injector that directly injects fuel into the cylinder,
2. The internal combustion engine according to claim 1, wherein the fuel injection control means drives the in-cylinder injector so as to inject both the fuel for the basic value and the fuel for the increased amount by intake stroke injection. Fuel injection control device. When the difference between the actual intake air amount of the cylinder and the predicted intake air amount used in the calculation of the basic value and the increase value is obtained after the intake stroke is completed or immediately before the intake stroke is completed, and the deviation is equal to or greater than a predetermined value Further includes a correction value calculation means for calculating a correction value of the fuel injection amount based on the deviation and the rotation speed difference,
5. The fuel injection control device for an internal combustion engine according to claim 4, wherein the fuel injection control means drives the in-cylinder injector so as to inject fuel for the correction value by compression stroke injection.   6. The fuel for an internal combustion engine according to claim 5, further comprising learning correction means for correcting the setting of the increase value with respect to the rotation speed difference by taking in a learning value calculated from the correction value into the increase value. Injection control device.   The learning correction means for correcting the setting of the increase value with respect to the rotation speed difference based on the degree of increase in the rotation speed of the input shaft of the automatic transmission is further provided. A fuel injection control device for an internal combustion engine according to the item. In a fuel injection control device for an internal combustion engine having a port injector for injecting fuel into an intake port and an in-cylinder injector for directly injecting fuel into a cylinder, and connected to a torque converter type automatic transmission,
An injection ratio setting means for setting an injection ratio between a fuel injection amount from the port injector and a fuel injection amount from the in-cylinder injector based on an operating state of the internal combustion engine;
An acceleration request detecting means for detecting an acceleration request;
A rotational speed difference measuring means for measuring a rotational speed difference between the rotational speed of the input shaft of the automatic transmission and the rotational speed of the output shaft of the internal combustion engine;
When the acceleration request is detected, if the rotational speed difference is greater than or equal to a predetermined value, the ratio of fuel injection by the port injector is reduced, and the ratio of fuel injection by the in-cylinder injector is increased. Injection ratio correction means for correcting
Fuel injection control means for driving the port injector and the in-cylinder injector based on the determined injection ratio;
A fuel injection control device for an internal combustion engine, comprising:

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