JP6981358B2 - Internal combustion engine control device - Google Patents

Description

The present invention relates to an internal combustion engine control device applied to an internal combustion engine provided with a port injection valve for injecting fuel into an intake passage.

For example, in Patent Document 1 below, the required injection amount determined based on the amount of air filled in the cylinder of an internal combustion engine is divided into a leading injection, which is an injection in the intake stroke, and a trading injection, which is an injection in the subsequent combustion stroke. The control device to be used is described.

Japanese Unexamined Patent Publication No. 5-256172

In order to reduce PN, which is the number of particulate matter (PM) in the exhaust, the inventor injects all the fuel of the required injection amount before the intake stroke by the intake asynchronous injection, instead of injecting the required injection amount. It was examined to inject a part of the above by the intake synchronous injection which injects in synchronization with the valve opening period of the intake valve. However, when the intake synchronous injection is executed, the time interval between the injection start timing and the combustion stroke is shorter than that of the intake asynchronous injection, which is disadvantageous in atomizing the fuel.

Hereinafter, means for solving the above problems and their actions and effects will be described.
1. 1. The control device of the internal combustion engine is applied to an internal combustion engine provided with a port injection valve that injects fuel into the intake passage, and is more than the intake synchronous injection that injects fuel in synchronization with the valve opening period of the intake valve and the intake synchronous injection. Two, a multi-injection process in which the intake asynchronous injection in which fuel is injected at the timing on the advance side is executed in the order of the intake asynchronous injection and the intake synchronous injection, and a single injection process in which fuel is injected only by the intake asynchronous injection. A selection process for selecting which of the three processes to be executed, an operation process for executing either the multi-injection process or the single injection process by operating the port injection valve according to the selection process, and 1 The above is more than the case where the proportion of the disturbance fuel which is the fuel other than the fuel injected from the port injection valve in the one combustion cycle is small in the amount of fuel filled in the combustion chamber of the internal combustion engine in the combustion cycle. A weight loss correction process for reducing the amount of fuel injected from the port injection valve in the one combustion cycle is executed by an operation process, and the selection process is the first ratio in a predetermined filling efficiency. In some cases, the multi-injection process is selected, and when the second ratio is larger than the first ratio, the single injection process is selected.

According to the above single injection process, the fuel can be atomized by injecting fuel as much as possible before the intake valve is opened, but when the amount of injected fuel increases, the amount of fuel adhering to the intake passage increases. There is a risk that the number will increase, which in turn will lead to an increase in PN. Therefore, in the above configuration, when the amount of fuel to be injected from the port injection valve in one combustion cycle is large due to the high filling efficiency, the multi-injection process is executed. As a result, the amount of fuel injected by the intake asynchronous injection, which tends to increase the amount of fuel adhered to the intake passage, can be reduced, so that the increase in PN can be suppressed. On the other hand, in the multi-injection process, the time for atomizing the fuel injected from the port injection valve is shortened by performing the intake synchronous injection, so that there is a concern that the amount of unburned fuel in the exhaust increases. However, in the region where the filling efficiency is high, it is advantageous to execute the multi-injection process in order to maintain good exhaust characteristics.

By the way, the fuel other than the fuel supplied from the port injection valve into the combustion chamber within one combustion cycle tends to be a fuel in a sufficiently atomized state, and this fuel contributes to combustion in the combustion stroke. Therefore, in the above configuration, the amount of fuel injected from the port injection valve is reduced in one combustion cycle by the weight loss correction process. When the weight loss correction is performed, even if the filling efficiency is the same, the amount of fuel adhering to the intake passage is reduced, so that the PN when the single injection process is performed becomes small. Therefore, in the above configuration, the multi-injection process is selected when the proportion of fuel other than the fuel injected from the port injection valve is small at a predetermined filling efficiency, while the second proportion is large. In that case, select single injection processing. As a result, compared to the case where the multi-injection process is always executed at a predetermined filling efficiency, the single injection process can be executed as much as possible while suppressing the generation of PN, and the fuel injected from the port injection valve is foggy. It is possible to secure the time to change.

2. 2. In the control device for the internal combustion engine according to 1 above, the canister that collects the fuel vapor in the fuel tank that stores the fuel injected from the port injection valve and the flow rate of the fluid that flows from the canister into the intake passage are adjusted. The adjustment device is applied to an internal combustion engine provided with the adjustment device, and the adjustment device is operated to execute a purge control process for controlling the flow rate of fuel steam flowing from the canister into the intake passage, and the weight loss correction process is performed. The operation process includes a process of reducing the amount of fuel injected from the port injection valve in the one combustion cycle as compared with the case where the ratio of the fuel steam as the ratio of the disturbance fuel is large and small.

In the above configuration, by executing the reduction correction based on the amount of fuel vapor flowing from the canister to the intake passage, it is possible to suppress the fluctuation of the amount of fuel supplied to the combustion chamber depending on the amount of fuel vapor.

3. 3. In the control device for the internal combustion engine according to 1 or 2, the base injection amount calculation process for calculating the base injection amount to a larger value than when the fresh air amount filled in the combustion chamber is large is executed, and the above-mentioned The weight loss correction process is a process for reducing the amount of the base injection amount, and the multi-injection process uses the fuel of the base injection amount corrected by the weight loss correction process as the injection amount of the intake asynchronous injection and the intake synchronous injection. Includes the process of dividing into the injection amount of.

In the above configuration, the base injection amount is reduced and corrected by the reduction correction process, so that the amount of fuel injected from the port injection valve by the multi-injection process is controlled to a value appropriate for the amount of fresh air filled in the combustion chamber. Can be done.

4. In the control device for the internal combustion engine according to the above 2 or 3, an acquisition process for acquiring information on the amount of fresh air flowing into the combustion chamber of the internal combustion engine is executed, and the selection process is based on the information acquired by the acquisition process. It includes a process of selecting a multi-injection process when the fresh air amount is equal to or more than a specified amount, and a process of setting the specified amount to a larger value when the ratio is large than when the ratio is small.

When the ratio is large, the amount of fuel injected from the port injection valve is reduced by the weight reduction correction process as compared with the case where the ratio is small. Therefore, the amount of fresh air when the PN becomes remarkable becomes larger. Therefore, in the above configuration, the single injection process can be selected as much as possible by setting the specified amount according to the above ratio.

5. In the control device for the internal combustion engine according to the above 3, the acquisition process for acquiring the base injection amount corrected by the weight loss correction process is executed, and the selection process is performed when the corrected base injection amount is equal to or larger than the specified amount. Includes a process of selecting the multi-injection process.

In the above configuration, since the multi-injection process is selected based on the base injection amount with the reduction correction, the multi-injection process can be selected according to the amount of fuel actually injected from the port injection valve. Therefore, it is possible to select the multi-injection process while grasping with high accuracy whether or not the PN becomes remarkable.

The figure which shows the control device and the internal combustion engine which concerns on 1st Embodiment. The block diagram which shows a part of the processing executed by the control device which concerns on the same embodiment. (A) and (b) are time charts showing the single injection process and the multi-injection process according to the same embodiment. The flow chart which shows the procedure of the injection valve operation processing which concerns on the same embodiment. The figure which shows the relationship between the PN generation rate and the filling efficiency by the single injection process which concerns on the same embodiment. The flow chart which shows the procedure of the injection valve operation processing which concerns on the 2nd Embodiment. The flow chart which shows the procedure of the injection valve operation processing which concerns on 3rd Embodiment. (A) and (b) are diagrams showing the relationship between the arrival end time of the multi-injection process and the amount of PN and HC generated.

<First Embodiment>
Hereinafter, the first embodiment of the control device of the internal combustion engine will be described with reference to the drawings.

A throttle valve 14 is provided in the intake passage 12 of the internal combustion engine 10 shown in FIG. 1, and a port injection valve 16 is provided downstream of the throttle valve 14. The air sucked into the intake passage 12 and the fuel injected from the port injection valve 16 flow into the combustion chamber 24 partitioned by the cylinder 20 and the piston 22 as the intake valve 18 opens. In the combustion chamber 24, the air-fuel mixture is subjected to combustion by the spark discharge of the ignition device 26, and the combustion energy generated at that time is converted into the rotational energy of the crank shaft 28 via the piston 22. .. The air-fuel mixture used for combustion is discharged to the exhaust passage 32 as exhaust gas when the exhaust valve 30 is opened. A catalyst 34 is provided in the exhaust passage 32.

The rotational power of the crank shaft 28 is transmitted to the intake side cam shaft 40 and the exhaust side cam shaft 42 via the timing chain 38. In the present embodiment, the power of the timing chain 38 is transmitted to the intake side camshaft 40 via the intake side valve timing adjusting device 44. The intake side valve timing adjusting device 44 is an actuator that adjusts the valve opening timing of the intake valve 18 by adjusting the rotational phase difference between the crank shaft 28 and the intake side cam shaft 40.

The fuel injected by the port injection valve 16 is stored in the fuel tank 50, and the fuel stored in the fuel tank 50 is pumped up by the fuel pump 52 and discharged toward the port injection valve 16. The fuel vapor generated in the fuel tank 50 is collected in the canister 54. The canister 54 and the intake passage 12 are connected by a purge passage 58, and the cross-sectional area of the fluid flow path in the purge passage 58 can be adjusted by the purge valve 56.

The control device 60 targets the internal combustion engine 10 as a control target, and in order to control the control amount (torque, exhaust component, etc.), the throttle valve 14, the port injection valve 16, the ignition device 26, and the intake side valve timing adjusting device. 44, operate the operation unit of the internal combustion engine 10 such as the purge valve 56. At this time, the control device 60 refers to the output signal Scr of the crank angle sensor 70, the air-fuel ratio Af detected by the air-fuel ratio sensor 72 provided on the upstream side of the catalyst 34, and the output signal Sca of the intake side cam angle sensor 74. do. Further, the control device 60 refers to the intake air amount Ga detected by the air flow meter 76 and the temperature (water temperature THW) of the cooling water of the internal combustion engine 10 detected by the water temperature sensor 78.

The control device 60 includes a power supply circuit 66 that supplies electric power to each location in the CPU 62, the ROM 64, and the control device 60, and the CPU 62 executes a program stored in the ROM 64 to control the control amount. do.

FIG. 2 shows a part of the processing executed by the control device 60. The process shown in FIG. 2 is realized by the CPU 62 executing the program stored in the ROM 64.
The intake phase difference calculation process M10 is based on the output signal Scr of the crank angle sensor 70 and the output signal Sca of the intake side cam angle sensor 74, and is the phase difference of the rotation angle of the intake side cam shaft 40 with respect to the rotation angle of the crank shaft 28. This is a process for calculating a certain intake phase difference DIN. The target intake phase difference calculation process M12 is a process for variably setting the target intake phase difference DIN * based on the operating point of the internal combustion engine 10. In this embodiment, the operating point is defined by the rotation speed NE and the filling efficiency η. Here, the CPU 62 calculates the rotation speed NE based on the output signal Scr of the crank angle sensor 70, and calculates the filling efficiency η based on the rotation speed NE and the intake air amount Ga. The filling efficiency η is a parameter that determines the amount of fresh air filled in the combustion chamber 24.

The intake phase difference control process M14 is a process of outputting an operation signal MS4 in order to operate the intake side valve timing adjusting device 44 in order to control the intake phase difference DIN * to the target intake phase difference DIN *.

The target purge rate calculation process M16 is a process of calculating the target purge rate Rp based on the filling efficiency η and the purge concentration learning value Lp described later. Here, the purge rate is a value obtained by dividing the flow rate of the fluid flowing from the canister 54 into the intake passage 12 by the intake air amount Ga, and the target purge rate Rp is the target value of the control purge rate.

The purge valve operation process M18 is a process of outputting an operation signal MS5 to the purge valve 56 in order to operate the purge valve 56 so that the purge rate becomes the target purge rate Rp based on the intake air amount Ga. Here, in the purge valve operation process M18, when the target purge rate Rp is the same, the smaller the intake air amount Ga, the smaller the opening degree of the purge valve 56. This is because the smaller the intake air amount Ga, the lower the pressure in the intake passage 12 than the pressure in the canister 54, so that the fluid easily flows from the canister 54 to the intake passage 12.

The base injection amount calculation process M20 is a process of calculating the base injection amount Qb, which is the base value of the fuel amount for setting the air-fuel ratio of the air-fuel mixture in the combustion chamber 24 as the target air-fuel ratio, based on the filling efficiency η. Specifically, in the base injection amount calculation process M20, for example, when the filling efficiency η is expressed as a percentage, the filling efficiency η is added to the fuel amount QTH for setting the air-fuel ratio as the target air-fuel ratio per 1% of the filling efficiency η. It may be a process of calculating the base injection amount Qb by multiplying by. The base injection amount Qb is a fuel amount calculated to control the air-fuel ratio to the target air-fuel ratio based on the amount of fresh air filled in the combustion chamber 24. Incidentally, the target air-fuel ratio may be, for example, the theoretical air-fuel ratio.

The feedback processing M24 calculates a feedback correction coefficient KAF obtained by adding "1" to the correction ratio δ of the base injection amount Qb as the feedback operation amount, which is the operation amount for feedback control of the air-fuel ratio Af to the target value Af *. It is a process to output. Specifically, the feedback process M24 outputs the output values of the proportional element and the differential element that input the difference between the air-fuel ratio Af and the target value Af *, and the output of the integral element that outputs the integrated value of the values corresponding to the difference. The sum with the value is the correction ratio δ.

The purge concentration learning process M26 is a process for calculating the purge concentration learning value Lp based on the correction ratio δ. The purge concentration learning value Lp is a correction ratio that corrects the deviation of the base injection amount Qb with respect to the injection amount required to control the target air-fuel ratio due to the inflow of fuel vapor from the canister 54 to the combustion chamber 24. It is a value converted per 1% of the rate. Here, in the present embodiment, all the factors that cause the feedback correction coefficient KAF to deviate from "1" when the target purge rate Rp is controlled to a value larger than "0" have flowed from the canister 54 into the combustion chamber 24. It is considered to be due to fuel vapor. That is, the correction ratio δ is regarded as a correction ratio for correcting the deviation of the base injection amount Qb with respect to the injection amount required for controlling the target air-fuel ratio due to the inflow of fuel vapor from the canister 54 to the intake passage 12. However, since the correction ratio δ depends on the purge rate, in the present embodiment, the purge concentration learning value Lp is set to the value “δ / Rp” per 1% of the purge rate.

Specifically, the exponential moving average processing value of the previous purge concentration learning value Lp (n-1) and the correction ratio “δ / Rp” per 1% of the purge rate is used as the current purge concentration learning value Lp ( n). FIG. 2 illustrates the weighting coefficients α and β of the previous purge concentration learning value Lp (n-1) and the value “δ / Rp” per 1% of the purge rate. Here, "α + β = 1".

The intake pressure estimation process M28 is a process of calculating the intake pressure Pm, which is the pressure downstream of the throttle valve 14 in the intake passage 12, based on the rotation speed NE and the intake air amount Ga. The intake air pressure estimation process M28 may be a process of calculating the intake air pressure Pm using, for example, an intake manifold model and an intake valve model. Here, the intake manifold model calculates the intake pressure Pm based on the inflow air amount at the time of valve closing and the intake air amount Ga. The amount of inflow air at the time of valve closing is a value excluding the amount of inflow air to the combustion chamber 24 in one combustion cycle, which is blown back to the intake passage 12 by the valve closing time of the intake valve 18. Specifically, in the intake manifold model, the rate of increase in the intake air pressure Pm is larger when the value obtained by subtracting the inflow air amount at the time of valve closing from the amount obtained by converting the intake air amount Ga into the amount per cylinder is larger than when the value is small. The intake pressure Pm is calculated so as to be. On the other hand, the intake valve model calculates the amount of inflow air when the valve is closed based on the intake pressure Pm and the rotation speed NE. In the intake valve model, when the intake pressure Pm is high, the amount of inflow air when the valve is closed is calculated to be larger than when it is low.

The predicted purge rate calculation process M30 is a process of calculating the predicted purge rate Rpe based on the target purge rate Rp, the intake pressure Pm, and the rotation speed NE. Here, the predicted purge rate Rpe is a purge rate for the fluid in the vicinity of the port injection valve 16. That is, even if the purge rate is controlled by the purge valve 56, the purge rate of the fluid in the vicinity of the port injection valve 16 does not change immediately and a response delay occurs. The predicted purge rate Rpe takes into consideration this response delay. The response delay time is set based on the intake pressure Pm and the rotation speed NE.

The purge correction ratio calculation process M32 is a process of calculating the purge correction ratio Dp by multiplying the purge concentration learning value Lp by the predicted purge rate Rpe. The purge correction ratio Dp is a correction ratio required for reducing and correcting the base injection amount Qb by the amount of fuel vapor, and has a negative value.

The purge correction coefficient calculation process M34 is a process of calculating the purge correction coefficient Kp, which is the correction coefficient of the base injection amount Qb, by adding "1" to the purge correction ratio Dp. The purge correction coefficient Kp is a value of "1" or less.

The correction process M36 is a process of calculating the required injection amount Qd by multiplying the base injection amount Qb by the feedback correction coefficient KAF and the purge correction coefficient Kp.
The injection valve operation process M38 is a process of outputting an operation signal MS2 to the port injection valve 16 in order to operate the port injection valve 16 based on the required injection amount Qd.

In the present embodiment, the fuel injection process has two types of processes, the process exemplified in FIG. 3 (a) and the process exemplified in FIG. 3 (b).
FIG. 3A is a single injection process for executing a single injection in which fuel injection is started before the intake valve 18 is opened and fuel injection is terminated before the intake valve 18 is opened.

FIG. 3B shows the fuel at the intake synchronous injection in which the fuel injection is started at the injection start timing Is in synchronization with the valve opening period of the intake valve 18 and the injection start timing Ins on the advance side of the intake synchronous injection. It is a multi-injection process that executes two fuel injections, an intake asynchronous injection that starts the injection of the fuel. In the present embodiment, the injection start timing Is of the intake synchronous injection is set to the advance angle side by a minute time ΔT with respect to the valve opening timing of the intake valve 18. Here, the minute time ΔT is set to the time required for the fuel injected from the port injection valve 16 to reach the position before the intake valve 18 is opened. This is a setting in which the injected fuel flows into the combustion chamber 24 as soon as possible when the intake valve 18 is opened. Since the process shown in FIG. 3A is a process for executing only the intake asynchronous injection, the injection start time is described as "injection start time Ins".

In the present embodiment, the multi-injection process is executed with the aim of reducing PN. That is, when the water temperature THW is low to some extent, the PN tends to increase when the single injection process is executed in the region where the filling efficiency η is large to some extent. It is considered that this is because when the filling efficiency η is large, the required injection amount Qd becomes a larger value than when it is small, and as a result, the amount of fuel adhering to the intake passage 12 increases. Specifically, when the amount of fuel adhering to the intake passage 12 increases to some extent, it is presumed that this is because a part of the adhering fuel flows into the combustion chamber 24 as droplets due to the shearing of the adhering fuel. Therefore, in the present embodiment, in the region where the filling efficiency η is large to some extent, a part of the required injection amount Qd is injected by the intake synchronous injection, so that the amount of fuel adhering to the intake passage 12 is large for the required injection amount Qd. Reduce the number, and eventually reduce PN.

FIG. 4 shows the procedure of the injection valve operation process M38. The process shown in FIG. 4 is realized by the CPU 62 repeatedly executing the program stored in the ROM 64, for example, at a predetermined cycle. In the following, the step number of each process is represented by a number prefixed with "S".

In the series of processes shown in FIG. 4, the CPU 62 first acquires the required injection amount Qd (S10). Next, the CPU 62 acquires the filling efficiency η and the rotation speed NE, which are a pair of parameters that define the operating point of the internal combustion engine 10 (S12). Then, the CPU 62 determines whether or not the operating point determined by the filling efficiency η and the rotation speed NE is in the region where the multi-injection process is executed (S14). In this process, a multi-injection area determined by the filling efficiency η and the rotation speed NE is stored in the ROM 64, and the CPU 62 determines whether or not the current operating point falls into the area. The region of the multi-injection process is a region where the filling efficiency η is large to some extent. However, even in the region where the filling efficiency η is large, the region where the rotation speed NE is large is excluded. This is because when the rotation speed NE is large, the time required for rotation of the unit crank angle is shorter than when the rotation speed NE is small, so that it is difficult to secure the time interval between the intake asynchronous injection and the intake synchronous injection. It is a thing.

When the CPU 62 determines that it is in the area of the multi-injection process (S14: YES), it is provisionally determined that the multi-injection process is to be executed, and whether or not the purge correction ratio Dp is smaller than the specified ratio Dpt which is a negative value. (S16). This process is a process for determining whether or not the required injection amount Qd can be a considerably small value for the large filling efficiency η because the absolute value of the purge correction ratio Dp is large. When the CPU 62 determines that the specified ratio is Dpt or more (S16: NO), the CPU 62 determines that the correction amount for reducing the base injection amount Qb by the purge correction ratio Dp is not so large, and sets the lower limit value ηL of the filling efficiency η as a reference. Substitute the value ηr (S18). On the other hand, when the CPU 62 determines that the ratio is smaller than the specified ratio Dpt (S16: YES), the CPU 62 substitutes the premium value ηp larger than the reference value ηr into the lower limit value ηL (S20).

When the processing of S18 and S20 is completed, the CPU 62 determines whether or not the filling efficiency η is equal to or greater than the lower limit value ηL (S22). This process is a process of determining whether or not to execute the multi-injection process. When the CPU 62 determines that the lower limit value is ηL or more (S22: YES), the required injection amount Qd is set to the asynchronous injection amount Qns which is the injection amount of the intake asynchronous injection and the synchronous injection amount Qs which is the injection amount of the intake synchronous injection. And (S24). Here, the CPU 62 divides the required injection amount Qd according to the rotation speed NE, the filling efficiency η, the water temperature THW, and the intake phase difference DIN. Specifically, the CPU 62 stores the synchronous injection amount Qs in advance with the map data having the rotation speed NE, the filling efficiency η, the water temperature THW, and the intake phase difference DIN as the input variables and the synchronous injection amount Qs as the output variable. Is calculated on the map. Then, the CPU 62 sets the asynchronous injection amount Qns to be a value obtained by subtracting the synchronous injection amount Qs from the required injection amount Qd.

The map data is a set of data of discrete values of input variables and values of output variables corresponding to the values of the input variables. In the map operation, for example, if the value of the input variable matches any of the values of the input variable of the map data, the value of the output variable of the corresponding map data is used as the operation result, and if they do not match, the value is included in the map data. The processing may be performed using the value obtained by interpolating the values of a plurality of output variables as the calculation result.

Then, the CPU 62 executes fuel injection in the order of intake asynchronous injection and intake synchronous injection, and outputs an operation signal MS2 to the port injection valve 16 in order to inject fuel having an asynchronous injection amount Qns and a synchronous injection amount Qs, respectively. The injection valve 16 is operated (S26).

On the other hand, when the CPU 62 determines negative in the processing of S14 and S22, it decides to execute the single injection processing (S28), and the port injection valve 16 is to inject the fuel of the required injection amount Qd by one fuel injection. The operation signal MS2 is output to operate the port injection valve 16 (S26).

When the processing of S26 is completed, the CPU 62 temporarily ends the series of processing shown in FIG.
Here, the operation and effect of this embodiment will be described.

The CPU 62 controls the purge rate by operating the purge valve 56, and at this time, the base injection amount Qb is reduced and corrected according to the purge correction ratio Dp. Since the fuel vapor flowing from the canister 54 into the intake passage 12 is atomized and is used for combustion in the combustion chamber 24, the air-fuel ratio is adjusted by feedforward-correcting the base injection amount Qb by the purge correction ratio Dp. It is possible to maintain high controllability.

Further, the CPU 62 executes the multi-injection process on condition that the filling efficiency η is equal to or higher than the lower limit value ηL. At this time, when the absolute value of the purge correction ratio Dp is large, the CPU 62 sets the lower limit value ηL to a large value. As a result, even if the filling efficiency η for which the multi-injection process should be executed when the absolute value of the purge correction ratio Dp is small, the single injection process is executed when the absolute value is large.

As shown in FIG. 5, the smaller the purge correction ratio Dp, that is, the larger the absolute value of the purge correction ratio Dp, the larger the filling efficiency η that reaches the allowable upper limit value PNth of PN shown by the alternate long and short dash line. It is in view of the fact that. According to the present embodiment, when the purge correction ratio Dp is small, the amount of fuel injected from the port injection valve 16 is small for the size of the filling efficiency η, and the amount of fuel adhering to the intake passage 12 is small. In view of this, the single injection process can be executed as much as possible. Therefore, compared to the case where the multi-injection process is executed when the filling efficiency η is equal to or higher than the reference value ηr, the concentration of unburned fuel in the exhaust becomes larger due to insufficient atomization of the fuel due to the intake synchronous injection. Can be suppressed.

In the example shown in FIG. 5, in the case where the purge correction ratio Dp is the first ratio Dp1 whose absolute value is smaller than the specified ratio Dpt at the predetermined filling efficiency η0 which is larger than the reference value ηr and smaller than the premium value ηp. The multi-injection process is executed, and when the second ratio Dp2 has an absolute value larger than the specified ratio Dpt, the single injection process is executed.

<Second embodiment>
Hereinafter, the second embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment.

FIG. 6 shows a procedure for processing the injection valve operation processing M38 according to the present embodiment. The process shown in FIG. 6 is realized by the CPU 62 repeatedly executing the program stored in the ROM 64, for example, at a predetermined cycle. For convenience, the same step numbers are assigned to the processes corresponding to the processes shown in FIG. 4 in FIG.

In the series of processes shown in FIG. 6, when the CPU 62 determines that the area is the multi-injection process (S14: YES), the lower limit value ηL is variably set according to the purge correction ratio Dp (S18a). Specifically, the CPU 62 continuously variably sets the lower limit value ηL according to the purge correction ratio Dp so that the lower limit value ηL becomes larger when the purge correction ratio Dp is smaller than when it is large. For example, this process may be a process in which the lower limit value ηL is mapped by the CPU 62 in a state where the map data having the purge correction ratio Dp as the input variable and the lower limit value ηL as the output variable is stored in the ROM 64 in advance.

When the process of setting the lower limit value ηL is completed, the CPU 62 shifts to the process of S22.
<Third embodiment>
Hereinafter, the third embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment.

FIG. 7 shows a procedure for processing the injection valve operation processing M38 according to the present embodiment. The process shown in FIG. 7 is realized by the CPU 62 repeatedly executing the program stored in the ROM 64, for example, at a predetermined cycle. For convenience, the same step numbers are assigned to the processes corresponding to the processes shown in FIG. 4 in FIG. 7.

In the series of processes shown in FIG. 7, when the CPU 62 determines that the area is the multi-injection process (S14: YES), the CPU 62 determines whether or not the required injection amount Qd is equal to or greater than the lower limit value Qth (S22a). Here, the lower limit value Qth is set according to a value at which PN may deviate from the allowable range if the single injection process is executed. When the CPU 62 determines that the lower limit value is Qth or more (S22a), the CPU 62 shifts to the processing of S24 in order to execute the multi-injection processing, while the CPU 62 determines that the lower limit value Qth is less than the lower limit value Qth (S22a: NO). Move to processing.

As described above, according to the present embodiment, by determining whether or not to execute the multi-injection process based on the required injection amount Qd, the multi-injection process is performed based on the injection amount actually injected by the port injection valve 16. It is possible to determine whether or not to execute.

Incidentally, if the base injection amount Qb when the filling efficiency η is, for example, the predetermined filling efficiency η0 shown in FIG. 5, is set to the lower limit value Qth, the feedback correction coefficient KAF is “1” at the predetermined filling efficiency η0. When the purge correction ratio Dp is zero, the multi-injection process is performed. Further, when the feedback correction coefficient KAF is "1" and the purge correction ratio Dp is smaller than zero, the single injection process is performed. As described above, even if the filling efficiency η is the same, the single injection process or the multi-injection process may be executed depending on the magnitude of the absolute value of the purge correction ratio Dp.

<Correspondence>
The correspondence between the matters in the above embodiment and the matters described in the above-mentioned "means for solving the problem" column is as follows. In the following, the correspondence is shown for each number of the solution means described in the column of "Means for solving the problem". [1] The selection process corresponds to the processes of S14 to S24 and 28 in FIG. 4, the processes of S14, S18a, S22 to S24 and S28 in FIG. 6, and the processes of S14, S22a, S24 and S28 in FIG. The operation process corresponds to the process of S26. The weight loss correction process corresponds to the purge correction ratio calculation process M32, the purge correction coefficient calculation process M34, and the correction process M36. The first ratio corresponds to the ratio determined by the first ratio Dp1 in FIG. 5, and the second ratio corresponds to the ratio determined by the second ratio Dp2. [2] The adjusting device corresponds to the purge valve 56, and the purge control process corresponds to the target purge rate calculation process M16 and the purge valve operation process M18. [3] The corrected base injection amount corresponds to the required injection amount Qd, and the division process corresponds to the process of S24. [4] The acquisition process corresponds to the process of S12. [5] The acquisition process corresponds to the process of S10.

<Other embodiments>
In addition, this embodiment can be changed and carried out as follows. The present embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.

・ "About weight loss correction processing"
In the above embodiment, as the weight loss correction process for reducing the base injection amount Qb, the weight loss correction process using the purge correction ratio Dp has been exemplified, but the present invention is not limited to this. For example, when an internal combustion engine having a configuration capable of discharging blow-by gas in a crankcase to an intake passage is adopted, the dilution correction process for correcting the base injection amount according to the fuel in the blow-by gas is reduced. It may be adopted as a process. Specifically, the dilution correction process can be learned according to the fuel concentration in the blow-by gas. Here, the fuel concentration can be executed in the same manner as the learning process of the purge concentration learning value Lp, based on, for example, the correction ratio δ by the air-fuel ratio feedback control when the purge valve 56 is closed. However, here, "δ / REF" is used instead of "δ / Rp". Here, the reflection rate REF is a parameter that becomes smaller when the intake air amount Ga is large than when it is small, and thus it is small when the intake air amount Ga is large even if the fuel concentration in the blow-by gas is the same. This reflects that the proportion of fuel flowing in from the crankcase in the combustion chamber 24 is smaller than in the case. Further, the correction ratio of the base injection amount Qb by the dilution correction processing may be calculated by multiplying the learned fuel concentration by the reflection rate REF.

・ "About the acquisition method of the ratio of disturbance fuel"
It is possible to obtain the ratio of the disturbance fuel, which is the fuel flowing into the combustion chamber 24, other than the fuel injected from the port injection valve 16 among the fuels filled in the combustion chamber 24 in one combustion cycle, based on the correction ratio δ. Not required. For example, an HC concentration sensor and a flow rate sensor may be provided in the purge passage 58, the flow rate of the disturbance fuel may be calculated based on the detection values of the sensors, and the ratio of the disturbance fuel may be calculated based on the calculation.

・ "About selection process"
In the above embodiment, a region for executing the multi-injection process is determined by the filling efficiency η and the rotation speed NE, and even when entering this region, the single injection process is performed according to the purge correction ratio Dp and the required injection amount Qd. It was decided to determine whether or not to execute, but it is not limited to this. For example, when the filling efficiency η is equal to or higher than the threshold value ηH determined according to the rotation speed NE, the single injection process is selected, and when the filling efficiency η is less than the threshold value ηH, either the single injection process or the multi-injection process is selected. The process of S22 or S22a may be used as the process of determining whether to select. Here, the threshold value ηH is set to the minimum interval that can secure a time interval between the injection end timing of the intake asynchronous injection and the injection start timing of the intake synchronous injection.

In the above embodiment, only the process of S14 is exemplified as a basic determination as to whether or not to execute the multi-injection process, but the present invention is not limited to this. For example, considering that the generation of PN becomes remarkable in the single injection process at a low temperature of the internal combustion engine, the execution of the multi-injection process indicates that the water temperature THW is below the specified temperature (for example, “70 ° C.”). In addition to the conditions, a process for determining whether or not the water temperature THW is below the specified temperature may be added.

・ "Required injection amount Qd"
As the required injection amount Qd, it is not essential that the base injection amount Qb is corrected by the feedback correction coefficient KAF. Further, for example, the required injection amount Qd may be the base injection amount Qb corrected by the feedback correction coefficient KAF and the learning value LAF. Incidentally, the calculation process of the learning value LAF is a process of inputting the feedback correction coefficient KAF and updating the learning value LAF so that the correction ratio of the base injection amount Qb by the feedback correction coefficient KAF becomes small. It is desirable that the learning value LAF is stored in an electrically rewritable non-volatile memory. Incidentally, in that case, it is desirable that the process of increasing the target purge rate Rp to be larger than "0" is executed after the learning value LAF has converged. As a result, the update process of the purge concentration learning value Lp is executed after the learning value LAF has converged, so that the update accuracy of the purge concentration learning value Lp is improved.

Further, the base injection amount Qb may be corrected by an increase coefficient that increases the required injection amount Qd more than when the water temperature THW is high.
・ "About intake synchronous injection"
In the above embodiment, as the intake synchronous injection, the one in which the injection start time Is is set immediately before the intake valve 18 is opened is exemplified, but the present invention is not limited to this, and the intake air is taken after the valve opening start time of the intake valve 18. The injection start time Is may be set when the valve 18 is open.

The intake synchronous injection may be a process in which the injection start time Is is calculated and then the injection end time is determined by the injection start time Is, but the present invention is not limited to this. For example, the arrival end time, which is the target value of the timing at which the fuel injected at the latest timing among the fuels injected from the port injection valve 16 reaches the position in the valve closing period of the intake valve 18, is calculated, and the arrival end time is calculated. The injection start time Is may be calculated based on the synchronous injection amount Qs and the rotation speed NE. Even in this case, the intake synchronous injection injects fuel in synchronization with the valve opening period of the intake valve 18.

Specifically, the intake synchronous injection injects the fuel so that the period during which the fuel injected from the port injection valve 16 reaches the position before the opening of the intake valve 18 falls within the valve opening period of the intake valve 18. .. Here, the start point of the "reaching period" is the timing at which the fuel injected at the earliest timing among the fuels injected from the port injection valve 16 reaches the position before valve opening, and the end point is the port injection. This is the timing at which the fuel injected at the latest timing among the fuels injected from the valve 16 reaches the position before the valve is opened. On the other hand, in the intake asynchronous injection, the fuel injected from the port injection valve 16 is injected so as to reach the intake valve 18 before the intake valve 18 opens. In other words, the intake asynchronous injection is an injection in which the fuel injected from the port injection valve 16 stays in the intake passage 12 until the intake valve 18 is opened, and then flows into the combustion chamber 24 after the valve is opened. be. In the intake asynchronous injection, the fuel is injected so that the period during which the fuel injected from the port injection valve 16 reaches the position before the opening of the intake valve 18 falls within the valve closing period of the intake valve 18. Is desirable.

Note that FIG. 8A shows the PN when the arrival end time of the intake asynchronous injection and the intake synchronous injection is changed, and FIG. 8B shows the arrival end of the intake asynchronous injection and the intake synchronous injection. The amount of HC generated when the time is changed is shown. Here, the white plot is when the arrival end time of the intake asynchronous injection is fixed and the arrival end time of the intake synchronous injection is changed, and the black plot is the arrival end time of the intake synchronous injection. Is fixed and the arrival end time of the intake asynchronous injection is changed. In addition, in each of the plots marked with a circle, diamond, square, and triangle, the ratio of the asynchronous injection amount Qns to the synchronous injection amount Qs is "8: 2", "7: 3", "6: 4", "5". : 5 ”corresponds to each.

As shown in the white plot of FIG. 8, the amount of PN and HC generated greatly changes depending on the change in the arrival end time of the intake synchronous injection.
・ "About single injection processing"
In the above embodiment, the single injection process is intended to end the injection of all fuel before the intake valve 18 is opened, but the present invention is not limited to this. For example, when the required injection amount Qd is large, the injection end timing may be on the retard side of the valve opening timing of the intake valve 18. However, it is desirable that the center of the injection period is located at least before the valve opening timing of the intake valve 18, and unless the required injection amount Qd is excessively large, it is desirable to use intake asynchronous injection.

・ "About the method of dividing the required injection amount Qd"
In the above embodiment, the fuel having the required injection amount Qd is divided into the synchronous injection amount Qs and the asynchronous injection amount Qns based on the rotation speed NE, the filling efficiency η, the water temperature THW, and the intake phase difference DIN, but the present invention is not limited to this. .. For example, the required injection amount Qd may be used instead of the filling efficiency η as the load parameter which is a parameter indicating the amount of air filled in the combustion chamber 24. Further, the four parameters of the load parameter, the rotation speed NE, the water temperature THW, and the intake phase difference DIN can be variably set based on only three of them, or variably set based on only two parameters. It may be variably set based on only one parameter. In addition to the above four parameters, for example, the intake pressure or the flow velocity of the intake air may be used. However, according to the above four parameters, the intake pressure and the flow velocity of the intake air can be grasped.

-"Purge control processing"
In the above embodiment, the target purge rate Rp is variably set according to the filling efficiency η, but the parameter for variably setting the target purge rate Rp is not limited to the filling efficiency η. Further, the target purge rate Rp may be set as a fixed value. Further, the opening degree of the purge valve 56 may be fully closed or binary controlled to a predetermined opening degree.

・ "About the adjustment device"
The adjusting device for adjusting the flow rate of the fluid from the canister to the intake passage is not limited to the purge valve 56. For example, the adjusting device may be configured by including a pump that sucks the fluid in the canister 54 and discharges it to the intake passage 12. The configuration including a pump is particularly effective when the internal combustion engine 10 includes a supercharger.

・ "About the variable intake valve characteristics device"
The characteristic variable device that changes the characteristics of the intake valve 18 is not limited to the intake side valve timing adjusting device 44. For example, the lift amount of the intake valve 18 may be changed. In this case, the parameter indicating the valve characteristics of the intake valve 18 is a lift amount or the like instead of the intake phase difference DIN.

・ "About control device"
The control device is not limited to the one provided with the CPU 62 and the ROM 64 to execute software processing. For example, a dedicated hardware circuit (for example, ASIC or the like) for hardware processing of at least a part of the software processed in the above embodiment may be provided. That is, the control device may have any of the following configurations (a) to (c). (A) A processing device that executes all of the above processing according to a program and a program storage device such as a ROM for storing the program are provided. (B) A processing device and a program storage device that execute a part of the above processing according to a program, and a dedicated hardware circuit for executing the remaining processing are provided. (C) A dedicated hardware circuit for executing all of the above processes is provided. Here, there may be a plurality of software processing circuits including a processing device and a program storage device, and a plurality of dedicated hardware circuits. That is, the processing may be performed by a processing circuit comprising at least one of one or more software processing circuits and one or more dedicated hardware circuits.

·"others"
It is not essential that the internal combustion engine 10 is provided with a characteristic variable device that changes the characteristics of the intake valve 18. It is not essential that the internal combustion engine 10 includes a throttle valve 14.

10 ... Internal combustion engine, 12 ... Intake passage, 14 ... Throttle valve, 16 ... Port injection valve, 18 ... Intake valve, 20 ... Cylinder, 22 ... Piston, 24 ... Combustion chamber, 26 ... Ignition device, 28 ... Crank shaft, 30 ... Exhaust valve, 32 ... Exhaust passage, 34 ... Catalyst, 38 ... Timing chain, 40 ... Intake side camshaft, 42 ... Exhaust side camshaft, 44 ... Intake side valve timing adjuster, 50 ... Fuel tank, 52 ... Fuel pump , 54 ... canister, 56 ... purge valve, 58 ... purge passage, 60 ... control device, 62 ... CPU, 64 ... ROM, 66 ... power supply circuit, 70 ... crank angle sensor, 72 ... air-fuel ratio sensor, 74 ... intake side cam angle Sensor, 76 ... air flow meter, 78 ... water temperature sensor.

Claims (5)

Applicable to internal combustion engines equipped with a port injection valve that injects fuel into the intake passage.
The intake synchronous injection and the intake synchronous injection that inject fuel at a timing on the advance side of the intake synchronous injection are the intake synchronous injection that injects fuel in synchronization with the valve opening period of the intake valve. A selection process for selecting which of the two processes, a multi-injection process to be executed in the order of the above, and a single injection process for injecting fuel only by the intake asynchronous injection, is to be executed.
An operation process for executing either the multi-injection process or the single injection process by operating the port injection valve according to the selection process, and
Compared to the case where the proportion of the disturbance fuel which is the fuel other than the fuel injected from the port injection valve in the one combustion cycle is small in the amount of fuel filled in the combustion chamber of the internal combustion engine in one combustion cycle. A weight loss correction process for reducing the amount of fuel injected from the port injection valve in the one combustion cycle by the operation process .
When the amount of fresh air filled in the combustion chamber is large, the base injection amount calculation process for calculating the base injection amount to a larger value than when it is small is executed.
In the selection process, the multi-injection process is selected when the ratio is the first ratio in a predetermined filling efficiency, and the single injection process is selected when the ratio is a second ratio larger than the first ratio. viewing including the process of selecting,
The weight loss correction process is a process for reducing the amount of the base injection amount.
The multi-injection process is a control device for an internal combustion engine including a process of dividing a fuel having a base injection amount corrected by the reduction correction process into an injection amount of the intake asynchronous injection and an injection amount of the intake synchronous injection. An internal combustion engine including a canister that collects fuel vapor in a fuel tank that stores fuel injected from the port injection valve, and an adjusting device that adjusts the flow rate of fluid flowing from the canister into the intake passage. Applied,
By operating the adjusting device, a purge control process for controlling the flow rate of fuel vapor flowing from the canister into the intake passage is executed.
The weight loss correction process is a process of reducing the amount of fuel injected from the port injection valve in the one combustion cycle by the operation process as compared with the case where the ratio of the fuel vapor as the ratio of the disturbance fuel is small. The control device for an internal combustion engine according to claim 1. The port injection valve that injects fuel into the intake passage, the canister that collects the fuel vapor in the fuel tank that stores the fuel injected from the port injection valve, and the flow rate of the fluid that flows from the canister into the intake passage. Applicable to internal combustion engines equipped with an adjusting device to adjust,
The intake synchronous injection and the intake synchronous injection that inject fuel at a timing on the advance side of the intake synchronous injection are the intake synchronous injection that injects fuel in synchronization with the valve opening period of the intake valve. A selection process for selecting which of the two processes, a multi-injection process to be executed in the order of the above, and a single injection process for injecting fuel only by the intake asynchronous injection, is to be executed.
An operation process for executing either the multi-injection process or the single injection process by operating the port injection valve according to the selection process, and
Compared to the case where the proportion of the disturbance fuel which is the fuel other than the fuel injected from the port injection valve in the one combustion cycle is small in the amount of fuel filled in the combustion chamber of the internal combustion engine in one combustion cycle. A weight loss correction process for reducing the amount of fuel injected from the port injection valve in the one combustion cycle by the operation process .
A purge control process that controls the flow rate of fuel vapor flowing from the canister into the intake passage by operating the adjusting device, and
The acquisition process of acquiring information on the amount of fresh air flowing into the combustion chamber of the internal combustion engine is executed.
The selection process is a process of selecting a multi-injection process when the fresh air amount based on the information acquired by the acquisition process is equal to or more than a specified amount, and a value larger than the case where the specified amount is small when the ratio is large. Including the process to set to
The weight loss correction process is a process of reducing the amount of fuel injected from the port injection valve in the one combustion cycle by the operation process as compared with the case where the ratio of the fuel vapor as the ratio of the disturbance fuel is small. Control device for internal combustion engine including. When the amount of fresh air filled in the combustion chamber is large, the base injection amount calculation process for calculating the base injection amount to a larger value than when it is small is executed.
The weight loss correction process is a process for reducing the amount of the base injection amount.
The internal combustion engine according to claim 3, wherein the multi-injection process includes a process of dividing a fuel having a base injection amount corrected by the reduction correction process into an injection amount of the intake asynchronous injection and an injection amount of the intake synchronous injection. Control device. The acquisition process for acquiring the base injection amount corrected by the weight loss correction process is executed.
The control device for an internal combustion engine according to claim 1 or 4 , wherein the selection process includes a process of selecting the multi-injection process when the corrected base injection amount is equal to or larger than a specified amount.

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