JP6369794B2 - Engine control device - Google Patents

Description

  The present invention relates to an engine control device, and more particularly, to an engine control device that performs cleaning control for removing deposits adhering to a nozzle of a fuel injection valve.

  This type of technology is disclosed in Patent Document 1, for example. Patent Document 1 discloses a technique for performing control (cleaning control) for injecting fuel from a fuel injection valve at an injection pressure higher than a normal injection pressure in order to remove deposits attached to the fuel injection valve. . In particular, in the technique disclosed in Patent Document 1, such cleaning control is performed even when the engine is idling.

JP2015-124757A

  Conventionally, as disclosed in Patent Document 1 described above, in cleaning control for removing deposits adhering to a fuel injection valve, control for increasing the injection pressure (fuel pressure) of the fuel injection valve is performed. By the way, in recent years, the injection pressure of the fuel injection valve is increased year by year from the viewpoint of improving fuel consumption and emission. Therefore, the injection pressure applied in the cleaning control tends to be further increased. Therefore, when cleaning control is performed in a low vehicle speed range or low engine rotation range such as during idling, abnormal noise generated in the fuel injection valve along with fuel injection may become a problem. In other words, the engine noise basically tends to be low at low vehicle speeds and low engine speeds. However, in this situation, if the injection pressure of the fuel injection valve is made considerably high by cleaning control, the fuel injection sound The conspicuousness (typically, the drive sound of the fuel injection valve) increases the possibility that the vehicle occupant will feel this sound as uncomfortable.

  The present invention has been made to solve the above-described problems of the prior art, and can appropriately suppress the uncomfortable feeling caused by the fuel injection sound by the cleaning control in the low vehicle speed range and the low engine rotation range. An object of the present invention is to provide an engine control device.

In order to achieve the above object, the present invention provides a fuel injection valve provided with a nozzle for fuel injection facing the combustion chamber, and a fuel injection valve for removing deposits adhering to the nozzle. Cleaning control means for performing cleaning control for increasing the injection pressure, and a control means for determining whether or not the engine speed is less than a predetermined speed. And a suppressing means for restricting an increase in the injection pressure of the fuel injection valve in the cleaning control when it is determined that the engine speed is less than the predetermined engine speed. The lower the number, the lower the upper limit value when the injection pressure is raised in the cleaning control, and the injection pressure setting means for setting the injection pressure lower when the increase in the injection pressure is restricted. The injection time of the fuel injection valve is made longer than when the rise of the fuel is not restricted, and the injection time of the fuel injection valve is made shorter when the cleaning control is executed than when the cleaning control is not executed , characterized in that.
According to the present invention configured as described above, when the engine speed is less than the predetermined speed, the cleaning control for removing deposits adhering to the nozzle of the fuel injection valve is suppressed. It can be appropriately suppressed that the fuel injection sound caused by the cleaning control in the low vehicle speed range is felt as uncomfortable. The fuel injection amount from the fuel injection valve can be appropriately maintained when the increase in the injection pressure is restricted and when it is not restricted. The fuel injection amount from the fuel injection valve can be appropriately maintained during the execution and non-execution of the cleaning control. Therefore, it is possible to suppress the uncomfortable feeling caused by the fuel injection sound by the cleaning control while securing the execution of the cleaning control to some extent.

In the present invention, preferably, the cleaning control is executed when a predetermined start condition is satisfied, and the suppression means suppresses the cleaning control by setting the cleaning control start condition to be stricter than when the cleaning control is not suppressed. To do.
According to the present invention configured as described above, it is possible to suppress the uncomfortable feeling caused by the fuel injection sound by the cleaning control while securing the execution of the cleaning control to some extent.

  In the present invention, preferably, a rotation speed equivalent to an idle operation of the engine may be applied as the predetermined rotation speed.

In another aspect, in order to achieve the above object, the present invention provides a fuel injection valve provided with a nozzle for fuel injection facing the combustion chamber, and a deposit attached to the nozzle. And a cleaning control means for executing cleaning control for increasing the injection pressure of the fuel injection valve, wherein the speed of the vehicle on which the engine is mounted is less than a predetermined speed. Determining means for determining whether or not the vehicle speed is less than a predetermined speed, and a suppression means for limiting an increase in the injection pressure of the fuel injection valve in the cleaning control , and The control device includes an injection pressure setting unit that sets an upper limit value when the injection pressure is increased in the cleaning control as the speed of the vehicle on which the engine is mounted is lower. When the increase in force is restricted, the fuel injection valve has a longer injection time than when the increase in injection pressure is not restricted, and the cleaning control is being executed when the cleaning control is being executed. It is characterized in that the injection time of the fuel injection valve is made shorter than when there is not .

  Also according to the present invention configured as in the other aspects described above, it is possible to appropriately suppress the uncomfortable feeling caused by the fuel injection sound by the cleaning control.

  According to the engine control device of the present invention, it is possible to appropriately suppress the uncomfortable feeling caused by the fuel injection sound by the cleaning control in the low vehicle speed range and the low engine rotation range.

1 is a schematic configuration diagram of an engine to which an engine control device according to an embodiment of the present invention is applied. It is a block diagram which shows the electric constitution of the control apparatus of the engine by embodiment of this invention. It is a flowchart which shows the execution determination process of the cleaning control by embodiment of this invention. It is a flowchart which shows the cleaning control execution process by embodiment of this invention.

  Hereinafter, an engine control apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.

<Engine configuration>
First, an engine to which an engine control apparatus according to an embodiment of the present invention is applied will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of an engine to which an engine control apparatus according to an embodiment of the present invention is applied.

  As shown in FIG. 1, the engine 1 is a gasoline engine, a cylinder 2 that forms a combustion chamber 2 a, a piston 4 that reciprocates within the cylinder 2, and a connecting rod 6 that has one end connected to the piston 4. And a crankshaft 8 to which the other end of the connecting rod 6 is connected, and a fuel supply device 10 for supplying fuel to the combustion chamber 2a.

  An intake system that supplies air to the combustion chamber 2a of the engine 1 is provided with an air cleaner 12 that purifies the intake air, and an intake passage 13 that extends from the air cleaner 12 to the intake port 20. An intake air temperature / flow rate sensor 14 for detecting the temperature and flow rate of the air taken in through 12, an electronically controlled throttle valve 16 for changing the intake air amount, and a throttle valve for detecting the opening of the throttle valve 16 A sensor 18 is provided. The air sucked through these intake systems flows into the combustion chamber 2a through the intake port 20 communicating with the intake opening of the combustion chamber 2a and the intake valve 22 that opens and closes the intake opening. The engine 1 also has a spark plug 23 that burns an air-fuel mixture obtained by injecting fuel into the air flowing into the combustion chamber 2a.

The exhaust gas combusted in the combustion chamber 2a is discharged to the exhaust system of the engine 1 through an exhaust port 24 communicating with the exhaust opening of the combustion chamber 2a and an exhaust valve 26 that opens and closes the exhaust opening. An exhaust system for exhausting the exhaust gas of the engine 1 includes an A / F sensor 28 (for example, a linear O ₂ sensor) and an oxygen sensor 32 (for example, a lambda O ₂ sensor) for detecting an air-fuel ratio, and an exhaust gas purification function. The first catalyst 30 and the second catalyst 34 having the above are provided.

  The engine 1 also includes a crank angle sensor 36 that detects the rotation angle of the crankshaft 8 and an engine water temperature sensor 38 that detects the temperature of engine cooling water (engine water temperature) flowing through the water jacket of the cylinder block of the engine.

  Next, the fuel supply device 10 includes a fuel tank 40 that stores fuel, a low-pressure fuel pump 42 that pumps fuel in the fuel tank 40, and a fuel filter 44 that filters the fuel pumped by the low-pressure fuel pump 42. A pressure regulator 46 that makes the pressurized pressure by the low-pressure fuel pump constant, a high-pressure fuel pump 48 that pressurizes the fuel pumped from the low-pressure fuel pump 42, and the pressure of the fuel pressurized by the high-pressure fuel pump 48 (fuel pressure) ), A fuel injection valve (injector) 52 that injects fuel pressurized by the high-pressure fuel pump 48 into the combustion chamber 2a, and a pressure supplied to the fuel injection valve 52 is a predetermined pressure. A relief valve 54 that is a second fuel pressure adjusting means for returning the pressurized fuel to the upstream side of the high-pressure fuel pump 48 when the pressure is as described above.

  Next, the engine 1 has a purge fuel control device 60. The purge fuel control device 60 communicates a canister 62 that stores purge fuel (evaporated fuel / evaporative gas) in the fuel tank 40 and that is filled with an adsorbent such as activated carbon, and the fuel tank 40 and the canister 62. And a relief passage 64 for relieving the purge fuel staying in the space of the fuel tank 40 to the canister 62. The canister 64 is provided with an air release passage 65 extending from the canister 64 and having a tip opened to the atmosphere.

  The purge fuel control device 60 communicates the canister 62 with the downstream portion of the throttle valve 16 in the intake passage 13 of the intake system, and supplies the purge fuel adsorbed by the canister 62 to the intake passage 13. 66 and a purge valve 68 that is provided in the purge passage 66 and controls the amount of purge fuel supplied from the canister 62 to the intake passage 13.

<Control block>
Next, the control block of the engine control apparatus according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is a block diagram showing an electrical configuration of the engine control apparatus according to the embodiment of the present invention.

  As shown in FIG. 2, the PCM (Power-train Control Module) 80 mainly includes detection signals from the A / F sensor 28, the crank angle sensor 36, the engine water temperature sensor 38, the fuel pressure sensor 50, and the vehicle speed sensor 70. Is entered. Specifically, the PCM 80 includes an air-fuel ratio detected by the A / F sensor 28, an engine speed corresponding to the crank angle detected by the crank angle sensor 36, and an engine water temperature detected by the engine water temperature sensor 38. The pressure of the fuel pressurized by the high-pressure fuel pump 48 (fuel pressure) detected by the fuel pressure sensor 50 and the speed of the vehicle (vehicle speed) detected by the vehicle speed sensor 70 are acquired.

  The PCM 80 mainly controls the throttle valve 16, the spark plug 23, the high-pressure fuel pump 48, the fuel injection valve 52, and the purge valve 68 based on these acquired various state values. Specifically, the PCM 80 controls the opening / closing timing and opening of the throttle valve 16, the ignition timing control of the spark plug 23, and the fuel injection timing and fuel injection time of the fuel injection valve 52 (in other words, the fuel injection period, in detail). Controls the fuel injection pulse width). The PCM 80 controls the fuel pressure (corresponding to the injection pressure from the fuel injection valve 52) generated by the high-pressure fuel pump 48. In this case, the PCM 80 performs feedback control of the high-pressure fuel pump 48 based on the fuel pressure detected by the fuel pressure sensor 50. Further, the PCM 80 controls the opening and closing of the purge valve 68 and the opening thereof to switch between introducing and stopping purge fuel from the canister 62 to the intake passage 13 and adjusting the amount of purge fuel introduced to the intake passage 13. To do.

  In particular, in the present embodiment, the PCM 80 performs cleaning control for increasing the injection pressure of the fuel injection valve 52 by the high-pressure fuel pump 48 and removing deposits adhering to the injection port of the fuel injection valve 52. Further, the PCM 80 performs purge control for introducing the purge fuel of the canister 62 into the cylinder 2 and performing combustion processing.

  Such a PCM 80 includes a CPU, various programs that are interpreted and executed on the CPU (including basic control programs such as an OS and application programs that are activated on the OS to realize specific functions), programs, and various data. It is comprised by the computer provided with internal memory like ROM and RAM for memorize | storing.

  Although details will be described later, the PCM 80 is a “cleaning control unit”, “purge control unit”, “determination unit”, “cleaning control suppression unit”, “purge control suppression unit”, “injection pressure setting unit” in the present invention. ”,“ Cleaning control interruption means ”,“ period setting means ”, and the like.

<Control details>
Next, the control content performed by the PCM 80 in the embodiment of the present invention will be described. First, an outline of control contents according to the present embodiment will be described.

  In the present embodiment, the PCM 80 displays deposits attached to the nozzle holes of the fuel injection valve 52 as described above in a low speed range where the engine speed is less than a predetermined speed and / or a low vehicle speed range where the vehicle speed is less than a predetermined speed. The cleaning control for removal is suppressed. Typically, the PCM 80 prohibits cleaning control in a low rotation range and / or a low vehicle speed range. By so doing, the vehicle occupant is restrained from feeling that the fuel injection sound (specifically, the driving sound of the fuel injection valve 52) due to the cleaning control in the low vehicle speed range or the low engine rotation range is uncomfortable. To do.

  In the present embodiment, the PCM 80 prohibits the purge control for introducing the purge fuel in the canister 62 into the cylinder 2 in principle during the cleaning control. The reason for this is as follows. If the injection pressure of the fuel injection valve 52 is increased while maintaining the fuel injection amount from the fuel injection valve 52 constant, the injection time (specifically, the fuel injection pulse width) of the fuel injection valve 52 is shortened. It becomes. Therefore, in the cleaning control, the injection pressure is increased in order to remove deposits adhering to the fuel injection valve 52, so the injection time of the fuel injection valve 52 is shortened. If purge control is to be performed during such cleaning control, in order to keep the fuel injection amount supplied to the cylinder 2 constant, it is necessary to reduce the fuel injection amount from the fuel injection valve 52 by the introduced purge fuel amount. In this way, the injection time of the fuel injection valve 52 must be further shortened. In this case, an injection time that does not ensure the controllability of the fuel injection valve 52 is applied, and this injection time cannot be properly realized, and a desired fuel injection amount cannot be injected from the fuel injection valve 52. There is sex. Therefore, in the present embodiment, the cleaning control is executed in a state where the purge control is stopped in order to appropriately ensure the shortening of the injection time accompanying the high-pressure injection during the cleaning control. That is, the cleaning control is not performed simultaneously with the purge control.

However, in the present embodiment, the PCM 80 causes the purge fuel in the canister 62 to be removed from the atmosphere opening passage 65 even when there is a request for execution of cleaning control, that is, in a situation where deposits adhering to the fuel injection valve 52 should be removed. In situations where there is a possibility of being released into the atmosphere, for example, when the purge fuel concentration (evaporative gas concentration) is relatively high, the cleaning control is prohibited and the purge control is executed with priority. In this way, regardless of the situation in which the purge control is to be executed, the purge control is prohibited by executing the cleaning control, so that the purge fuel amount exceeds the purge fuel acceptable amount of the canister 62 and the purge fuel is in the atmosphere. To prevent it from being released.
The reason why the cleaning control is not performed simultaneously with the purge control when performing the purge control is the same as described above. That is, the injection pressure and the injection time to be applied in the cleaning control (specifically, the high injection pressure that can appropriately remove the deposit and the shortened injection time necessary to realize the injection pressure) cannot be realized. This is to suppress the occurrence of problems.

  In this embodiment, the PCM 80 interrupts the cleaning control when a predetermined period (set to a period shorter than the period necessary for removing the deposit by the cleaning control) has elapsed since the cleaning control started. Thus, it is determined whether or not the purge fuel in the canister 62 may be released to the atmosphere. In this case, the PCM 80 performs the determination by determining the purge fuel concentration by interrupting the cleaning control, performing the purge control for a short time, and introducing the purge fuel into the cylinder 2. When the purge fuel concentration is relatively low, the PCM 80 determines that the possibility that the purge fuel is released to the atmosphere is low, and cancels the interruption of the cleaning control, thereby restarting the cleaning control. On the other hand, when the purge fuel concentration is relatively high, the PCM 80 determines that the purge fuel is likely to be released to the atmosphere, and continues the cleaning control interruption to perform the purge control. Reduce the purge fuel concentration. By so doing, purge control is prohibited for a relatively long time for cleaning control, thereby preventing the purge fuel in the canister 62 from being released to the atmosphere.

  Next, specific control contents performed by the PCM 80 in this embodiment will be described with reference to FIGS. FIG. 3 is a flowchart showing the cleaning control execution determination process according to the embodiment of the present invention, and FIG. 4 is a flowchart showing the cleaning control execution process according to the embodiment of the present invention.

When the cleaning control execution determination process in FIG. 3 is started, first, in step S11, the PCM 80 determines whether or not the cleaning control execution condition is satisfied. This cleaning control execution condition includes the following plurality of conditions.
(1) The fuel injection learning is completed. (2) The purge fuel concentration learning value is highly reliable. (3) The purge fuel concentration is less than the predetermined value. (4) The status is incomplete. (5) The engine water temperature is equal to or higher than the predetermined temperature. (6) The vehicle speed is equal to or higher than the predetermined speed. (7) The engine speed is equal to or higher than the predetermined speed.

  Here, the conditions (1) to (7) constituting the cleaning control execution condition will be specifically described. First, the condition (1) “Fuel injection learning is completed” is a prerequisite for obtaining the purge fuel concentration as described above. Usually, fuel injection learning of the fuel injection valve 52 is performed based on the air-fuel ratio detected by the A / F sensor 28 when fuel is injected from the fuel injection valve 52 in a state where purge fuel is not introduced into the cylinder 2. (Learning about variations in parts of the fuel injection valve 52 and deterioration over time). Specifically, the relationship between the fuel injection amount commanded to the fuel injection valve 52 and the air-fuel ratio detected by the A / F sensor 28 when this fuel injection amount is actually injected from the fuel injection valve 52. Based on the above, fuel injection learning of the fuel injection valve 52 is performed (this learning includes checking the reliability of the A / F sensor 28). Then, after the completion of such fuel injection learning, a small amount of purge fuel is introduced to obtain the purge fuel concentration based on the result of the above fuel injection learning and the air-fuel ratio detected by the A / F sensor 28. It will be. In this case, the introduced purge is obtained by subtracting the air-fuel ratio variation (obtained from the result of fuel injection learning) due to fuel injection from the fuel injection valve 52 from the air-fuel ratio detected by the A / F sensor 28. The purge fuel concentration can be obtained from the value corresponding to the difference in the air-fuel ratio (the determination of the purge fuel concentration is included in the learning of the purge fuel concentration). For this reason, it is necessary to complete the fuel injection learning in order to acquire the purge fuel concentration. For example, the reliability of the A / F sensor 28 is confirmed by the fuel injection learning. Since it is necessary, the condition (1) is applied as an execution condition for the cleaning control.

  Next, the condition (2) “reliability of the learned value of the purge fuel concentration is high”, but since the purge fuel concentration is used in the later condition (3), the acquired purge fuel concentration The fact that the reliability of the above is assured in the first place is applied as an execution condition of the cleaning control. As described above, the learning of the purge fuel concentration is performed based on the air-fuel ratio detected by the A / F sensor 28 when the purge fuel is introduced into the cylinder 2 using the fuel injection learning result. For example, a condition that the number of times the learning value of the purge fuel concentration is updated is equal to or greater than a predetermined value (about 3 to 5 times) is applied as a condition that “the reliability of the learning value of the purge fuel concentration is high”.

  Next, the condition (3) “Purge fuel concentration is less than a predetermined value” is used. As described above, in this embodiment, purge control is prohibited during cleaning control. In order to prevent the purge fuel from being released into the atmosphere during the prohibition, the condition (3) that the purge fuel concentration is relatively low is applied as the cleaning control execution condition. From this point of view, the predetermined value for determining the purge fuel concentration is within the canister 62 even if the purge control is prohibited for a relatively long time (for example, about 2 to 3 minutes from the start of the cleaning control) to execute the cleaning control. The purge fuel concentration is applied so that no purge fuel is released into the atmosphere.

  Next, under the condition (4) “Status is that cleaning is not completed”, this cleaning is not completed. In the subsequent steps S14 and S15, the current situation is that deposits adhere to the fuel injection valve 52. It is set when it is determined that the deposit should be removed. Therefore, in (4), the condition that the current situation is a situation in which the deposit attached to the fuel injection valve 52 should be removed is applied as the cleaning control execution condition.

  Next, (5) is the condition that the engine water temperature is equal to or higher than a predetermined temperature. In (5), the condition that the engine 1 is warmed up, for example, the engine water temperature is 60 ° C. or higher. Is applied as a cleaning control execution condition. This is because when the engine 1 is not warmed up, control other than the cleaning control (such as warm-up control of the engine 1) is prioritized.

  Next, (6) is a condition that “the vehicle speed is equal to or higher than a predetermined speed”. This condition suppresses that the vehicle occupant feels that the fuel injection sound by the cleaning control in the low vehicle speed range is uncomfortable. Therefore, it is applied as an execution condition for cleaning control. For example, a vehicle speed (about 8 km / h) slightly higher than the vehicle speed due to the creep phenomenon is applied to the predetermined speed for determining the vehicle speed in an automatic vehicle.

  Next, the condition (7) “the engine speed is equal to or higher than the predetermined speed” is the condition that the vehicle occupant feels uncomfortable with the fuel injection sound caused by the cleaning control in the low engine speed range. In order to suppress this, the cleaning control is applied as an execution condition. For example, the number of revolutions corresponding to the idle operation of the engine 1 (about 500 to 600 rpm) is applied as the predetermined number of revolutions for determining the engine revolution number.

  Note that, as in (6) and (7), the conditions for executing the cleaning control are defined by the vehicle speed and the engine speed when the vehicle speed and the engine speed are low (that is, the engine speed). This is because when the load is low, the amount of fuel injection is small, and therefore there is a problem that the injection time cannot be increased appropriately by shortening the injection time in the cleaning control.

  Returning to FIG. 3, when it is determined that the cleaning control execution condition as described above is satisfied (step S11: Yes), that is, all the conditions (1) to (7) constituting the cleaning control execution condition. If is established, the process proceeds to step S12. In step S12, the PCM 80 performs a cleaning control execution process for executing the cleaning control. The cleaning control execution process will be described in detail with reference to FIG. 4 later.

  On the other hand, if it is not determined that the cleaning control execution condition is satisfied (step S11: No), that is, any of the conditions (1) to (7) constituting the cleaning control execution condition is not satisfied. If so, the process proceeds to step S13. In step S13, the PCM 80 integrates the amount of fuel injected from the fuel injection valve 52 below the predetermined fuel pressure or below the predetermined flow rate (the integrated fuel amount is referred to as “first integrated amount”). A relatively low fuel pressure or flow rate at which deposits are likely to adhere to the fuel injection valve 52 is applied to the predetermined fuel pressure or flow rate. Such a relatively low fuel pressure or flow rate is applied, for example, at low vehicle speed operation (low load operation).

  Next, in step S14, the PCM 80 determines whether or not the first integrated amount obtained in step S13 is greater than or equal to a predetermined value. In this step S14, the PCM 80 determines whether or not the current situation is a situation in which deposits are attached to the fuel injection valve 52 and this deposit should be removed. For example, the amount that the first integrated amount reaches when low vehicle speed operation (low load operation) continues for about 30 minutes is applied to the predetermined value used in the determination in step S14. In the case of this example, the determination in step S14 corresponds to determining whether or not the low load operation in which the fuel injection less than the predetermined fuel pressure or less than the predetermined flow rate is applied has continued for about 30 minutes. Therefore, in another example, instead of steps S13 and S14 as described above, the time during which fuel injection less than a predetermined fuel pressure or less than a predetermined flow rate is applied may be counted, and the determination for the counted time may be performed. .

  If the result of determination in step S14 is that the first integrated amount is greater than or equal to a predetermined value (step S14: Yes), the process proceeds to step S15. In step S <b> 15, the PCM 80 determines that the current situation is a situation where the deposit attached to the fuel injection valve 52 should be removed, and sets the status to “uncleaned”. In addition, the PCM 80 resets the first accumulated amount that has been counted. On the other hand, when the first integrated amount is less than the predetermined value (step S14: No), the PCM 80 ends the process without setting the status to “uncleaned”.

  Next, the cleaning control execution process of FIG. 4 will be described. This cleaning control execution process is executed in step S12 of FIG.

  When the cleaning control execution process is started, first, in step S21, the PCM 80 controls the purge valve 68 to be fully closed in order to stop the purge control for the cleaning control. By doing so, the introduction of the purge fuel into the cylinder 2 is stopped.

  Next, in step S <b> 22, the PCM 80 performs control for increasing the injection pressure of the fuel injection valve 52 by the high-pressure fuel pump 48 as cleaning control in order to remove deposits attached to the injection port of the fuel injection valve 52. In this case, the PCM 80 increases the injection pressure of the fuel injection valve 52 to a pressure that can appropriately remove the deposit of the fuel injection valve 52. For example, the PCM 80 increases the injection pressure of the fuel injection valve 52 to about 20 Mpa (in this configuration, an injection pressure of about 3 Mpa is applied during idle operation). Further, when the PCM 80 increases the injection pressure in this way, the injection time of the fuel injection valve 52 is shortened according to the amount by which the injection pressure is increased. That is, the PCM 80 shortens the injection time by an amount corresponding to the increase in the injection pressure in order to maintain the fuel injection amount from the fuel injection valve 52.

  Next, in step S23, the PCM 80 integrates the amount of fuel injected from the fuel injection valve 52 at a predetermined fuel pressure or higher and a predetermined flow rate or higher (the integrated fuel amount is referred to as a “second integrated amount”). As this predetermined fuel pressure, a minimum fuel pressure (injection pressure) that can remove deposits adhering to the injection port of the fuel injection valve 52 is applied. Such a fuel pressure (injection pressure) corresponds to the flow rate of the fuel injected from the fuel injection valve 52, but the predetermined flow rate is further used in obtaining the second integrated amount in step S23. This is because the energy of the fluid passing through the fuel injection valve 52 in consideration of the fuel flow rate in addition to the fuel flow rate affects the deposit removal.

  Next, in step S24, the PCM 80 determines whether the above-described cleaning control execution condition is not satisfied, that is, whether any of the conditions (1) to (7) constituting the cleaning control execution condition is not satisfied. Determine. In one example, the PCM 80 determines that the cleaning control execution condition is no longer satisfied when the vehicle speed is less than a predetermined speed or when the engine speed is less than the predetermined speed.

As a result of the determination in step S24, when the cleaning control execution condition is not satisfied (step S24: Yes), the process proceeds to step S25. In step S25, the PCM 80 stops increasing the injection pressure of the fuel injection valve 52 by the high-pressure fuel pump 48 in order to stop the cleaning control. Specifically, the PCM 80 returns the injection pressure of the fuel injection valve 52 to the normal pressure (that is, when cleaning control is not executed). In step S26, the PCM 80 releases the stop of the purge control, in other words, permits the introduction of the purge fuel into the cylinder 2.
Thereafter, when the cleaning control execution condition is satisfied again (step S11 in FIG. 3: Yes), the cleaning control execution process in FIG. 4 is performed, so that the cleaning control is resumed. Basically, the cleaning control is executed until the status is set to “cleaning completed” (set in step S28 described later).

  On the other hand, when the cleaning control execution condition is satisfied (step S24: No), the process proceeds to step S27. In step S27, the PCM 80 determines whether or not the second integrated amount obtained in step S23 is greater than or equal to a predetermined value. In step S27, the PCM 80 determines whether or not the current state is a state in which the deposit of the fuel injection valve 52 has been removed. The predetermined value used in the determination of step S27 is the integrated amount of fuel required for deposit removal when fuel injection is performed at a predetermined fuel pressure or higher and a predetermined flow rate or higher in low vehicle speed operation (low load operation) (maximum required for deposit removal). Corresponding to the amount of fuel). For example, the amount that the second integrated amount reaches when the low load operation continues for about 5 minutes is applied to the predetermined value used in the determination in step S27. In the case of this example, the determination in step S27 corresponds to determining whether or not the low-load operation to which fuel injection at a predetermined fuel pressure or higher and a predetermined flow rate or higher has been applied has continued for about 5 minutes. Therefore, in another example, instead of steps S23 and S27 as described above, the time during which fuel injection at a predetermined fuel pressure or higher and a predetermined flow rate or higher is applied may be counted, and the determination for the counted time may be performed. .

  As a result of the determination in step S27, when the second integrated amount is greater than or equal to a predetermined value (step S27: Yes), the process proceeds to step S28. In step S28, the PCM 80 determines that the deposit of the fuel injection valve 52 has been removed, and sets the status to “cleaning complete”. In addition, the PCM 80 resets the second accumulated amount that has been counted. Thereafter, the PCM 80 proceeds to steps 25 and S26 described above, finishes the cleaning control, and restarts the purge control. On the other hand, when the second integrated amount is less than the predetermined value (step S27: No), the PCM 80 determines that the deposit of the fuel injection valve 52 has not yet been removed, and sets the status to “cleaning completed”. Instead, the process proceeds to step S29.

  The period for executing the cleaning control is limited by executing the cleaning control until the second integrated amount becomes a predetermined value or more as described above. The reason for this is as follows. . In the state where the injection pressure of the fuel injection valve 52 is high, when the accelerator opening becomes 0, the fuel injection is stopped (fuel cut). In this case, generally, since the pressure reducing mechanism for reducing the fuel pressure is not provided in the fuel supply system, the state in which the injection pressure of the fuel injection valve 52 is high is maintained for a certain period of time. When the fuel injection is resumed near the idle operation in such a high injection pressure state, the fuel injection tends to be performed in a considerably short injection time (fuel injection pulse width). In this case, the fuel injection amount may be slightly increased without realizing the injection time corresponding to the high injection pressure. In the cleaning control, since a high injection pressure is actively used, such a situation is likely to occur. Therefore, in the present embodiment, the scenes for executing the cleaning control are limited. Specifically, the period (for example, about 5 minutes) for executing the cleaning control is limited. By doing so, deterioration of fuel consumption and emission caused by cleaning control is suppressed.

  Next, in step S29, the PCM 80 determines whether or not a predetermined time has elapsed since the cleaning control was started. In this step S29, the PCM 80 determines whether or not the cleaning control should be interrupted to check the purge fuel concentration, that is, confirms the possibility that the purge fuel in the canister 62 is released to the atmosphere. It is determined whether or not the situation should be. For example, when the period for executing the cleaning control is limited to about 5 minutes, a time of about 2 to 3 minutes shorter than the period for executing the cleaning control is applied to the predetermined time used in the determination in step S29. Is done. Normally, purge control for confirming the purge fuel concentration is performed at a constant cycle, but a time corresponding to such a cycle may be applied as it is to the predetermined time in step S29.

  If the result of determination in step S29 is that a predetermined time has not elapsed since the start of cleaning control (step S29: No), processing returns to step S21. In this case, the PCM 80 performs again the processing from step S21 onward in order to continue the cleaning control without performing the purge control for confirming the purge fuel concentration.

  On the other hand, when the predetermined time has elapsed from the start of the cleaning control (step S29: Yes), the process proceeds to step S30. In step S30, the PCM 80 stops increasing the injection pressure of the fuel injection valve 52 by the high-pressure fuel pump 48 in order to interrupt the cleaning control. Specifically, the PCM 80 returns the injection pressure of the fuel injection valve 52 to the normal pressure (that is, when cleaning control is not executed). In step S31, the PCM 80 cancels the purge control stop, opens the purge valve 68, and introduces purge fuel into the cylinder 2.

  Next, in step S32, the PCM 80 obtains the purge fuel concentration based on the air-fuel ratio detected by the A / F sensor 28 after introducing the purge fuel into the cylinder 2 and performing the combustion process, and the purge fuel concentration is equal to or higher than a predetermined value. It is determined whether or not. In step S32, it is determined whether or not the current situation is such that the purge fuel amount exceeds the purge fuel acceptable amount of the canister 62 and the purge fuel is released to the atmosphere. From such a viewpoint, the predetermined value used in the determination in step S32 is applied with a purge fuel concentration that may cause the purge fuel to be released to the atmosphere.

  As a result of the determination in step S32, when the purge fuel concentration is less than the predetermined value (step S32: No), the process returns to step S21. In this case, the PCM 80 determines that the purge fuel is unlikely to be released to the atmosphere, and cancels the interruption of the cleaning control and restarts the processes after step S21 in order to resume the cleaning control. Run.

If the result of determination in step S32 is that the purge fuel concentration is greater than or equal to a predetermined value (step S32: Yes ), the process ends. In this case, the PCM 80 determines that the purge fuel is likely to be released to the atmosphere, continues the cleaning control interruption, and continues the purge control so as to reduce the purge fuel concentration. To do. Thereafter, when the purge fuel concentration becomes less than the predetermined value, it is determined in step S11 in FIG. 3 that the cleaning control execution condition is satisfied, and the cleaning control execution process in FIG. 4 is performed, whereby the cleaning control is resumed. It will be. Basically, the cleaning control is executed until the second integrated amount becomes a predetermined value or more and the status is set to “cleaning completed”.

<Effect>
Next, functions and effects of the engine control apparatus according to the embodiment of the present invention will be described.

  According to the present embodiment, the PCM 80 performs cleaning control for removing deposits adhering to the nozzle of the fuel injection valve 52 when the engine speed is less than the predetermined speed and when the vehicle speed is less than the predetermined speed. Ban. As a result, it is possible to appropriately suppress the vehicle occupant from feeling that the fuel injection sound (specifically, the driving sound of the fuel injection valve 52) due to the cleaning control in the low vehicle speed range or the low engine rotation range is uncomfortable. it can. Further, the PCM 80 shortens the injection time of the fuel injection valve 52 when executing such cleaning control, compared with when the cleaning control is not executed. The fuel injection amount can be appropriately maintained.

  Further, according to the present embodiment, the PCM 80 prohibits the cleaning control and preferentially executes the purge control when the purge fuel concentration is a predetermined value or more. Thus, regardless of the situation in which purge control is to be executed, the purge control is prohibited by executing the cleaning control, so that the purge fuel amount exceeds the purge fuel acceptable amount of the canister 62 and the purge fuel is released to the atmosphere. Can be appropriately suppressed.

  Further, according to the present embodiment, the PCM 80 performs the determination as to whether or not the purge fuel concentration is equal to or higher than the predetermined value after the completion of the purge fuel concentration learning, so that the purge fuel concentration is accurately determined. be able to. In addition, according to the present embodiment, the PCM 80 performs the learning of the purge fuel concentration after the completion of the fuel injection learning of the fuel injection valve 52, so that the purge fuel concentration can be accurately learned.

  Further, according to the present embodiment, the PCM 80 interrupts the cleaning control when a predetermined period has elapsed from the start of the cleaning control. Thereby, when the cleaning control is interrupted, it is possible to appropriately determine whether or not the subsequent cleaning control can be continued. Specifically, the purge control is performed when the cleaning control is interrupted to obtain the purge fuel concentration. Based on the purge fuel concentration, the possibility that the purge fuel in the canister 62 is released to the atmosphere is determined, and the cleaning is performed. It is possible to appropriately determine whether control can be resumed. Therefore, according to this embodiment, the purge control is prohibited for a relatively long time for the cleaning control, so that the purge fuel in the canister 62 can be reliably prevented from being released to the atmosphere.

<Modification>
Below, the modification of above-described embodiment is demonstrated.

  In the above-described embodiment, the cleaning control is prohibited when the vehicle speed is less than the predetermined speed and the engine speed is less than the predetermined speed. However, in other examples, when the vehicle speed is less than the predetermined speed and the engine Cleaning control may be prohibited in any of the cases where the rotational speed is less than the predetermined rotational speed. In short, the cleaning control may be prohibited when there is a possibility that the vehicle occupant may feel the fuel injection sound due to the cleaning control as uncomfortable.

  Further, in the above-described embodiment, the cleaning control is prohibited according to a predetermined condition. However, the present invention is not limited to uniformly prohibiting the cleaning control as described above. In another example, the fuel injection in the cleaning control is performed. The increase in the injection pressure of the valve 52 may be limited to suppress the cleaning control. In one example, when the vehicle speed is low, the upper limit value for raising the injection pressure may be set lower than when the vehicle speed is high. In a typical example, the lower the vehicle speed, the lower the upper limit value for increasing the injection pressure may be set. In another example, when the engine speed is low, the upper limit value for raising the injection pressure may be set lower than when the engine speed is high. In a typical example, the lower the engine speed, the lower the upper limit value for increasing the injection pressure may be set. Further, when the increase in the injection pressure is limited in this way, the injection time of the fuel injection valve 52 may be made longer than when the increase in the injection pressure is not limited. Thereby, the fuel injection amount can be appropriately maintained.

  In yet another example, the cleaning control execution condition (in other words, the cleaning control start condition) may be tightened to suppress the cleaning control. For example, when the cleaning control is suppressed, the predetermined value for determining the number of updates of the learning value of the purge fuel concentration is increased or the predetermined speed for determining the vehicle speed is set higher than when the cleaning control is not suppressed. What is necessary is just to raise or the predetermined rotation speed for judging an engine speed.

  In the above-described embodiment, the cleaning control is interrupted when a predetermined time has elapsed from the start of the cleaning control. However, in another example, the predetermined time applied when interrupting the cleaning control may be changed. For example, the predetermined time may be changed according to the purge fuel concentration. In this case, the higher the purge fuel concentration, the shorter the predetermined time. In another example, the predetermined time is changed in accordance with the amount of purge fuel that canister 62 can accept at the start of cleaning control (the amount corresponding to the purge fuel concentration) without using such purge fuel concentration. May be. In this case, the predetermined time may be shortened as the purge fuel acceptable amount is smaller.

  In the above-described embodiment, the determination is made using the purge fuel concentration in the cleaning control execution condition or the like, but the purge introduced from the canister 62 to the intake passage 13 via the purge passage 66 instead of the purge fuel concentration. A fuel amount or a purge flow rate may be used. In short, a parameter that can determine the possibility of purge fuel being released into the atmosphere in the purge system (typically corresponding to the amount of purge fuel that canister can be received) may be used. Note that the purge fuel concentration, the purge fuel amount, and the purge flow rate correspond to purge fuel related values that are parameters related to the purge fuel.

1 Engine 2 Cylinder 10 Fuel Supply Device 16 Throttle Valve 23 Spark Plug 28 A / F Sensor 36 Crank Angle Sensor 38 Engine Water Temperature Sensor 48 High Pressure Fuel Pump 50 Fuel Pressure Sensor 52 Fuel Injection Valve 60 Purge Fuel Control Device 62 Canister 68 Purge Valve 70 Vehicle Speed Sensor 80 PCM

Claims (4)

A fuel injection valve provided such that a nozzle hole for fuel injection faces the combustion chamber;
Cleaning control means for performing cleaning control for increasing the injection pressure of the fuel injection valve in order to remove deposits attached to the injection hole;
An engine control device comprising:
The controller is
Determining means for determining whether the engine speed is less than a predetermined engine speed;
Suppression means for limiting an increase in the injection pressure of the fuel injection valve in the cleaning control when it is determined that the engine speed is less than the predetermined speed ;
Further, the control device has an injection pressure setting means for setting a lower upper limit value when the injection pressure is increased in the cleaning control as the engine speed is lower,
When the increase in the injection pressure is restricted, the fuel injection valve has a longer injection time than when the increase in the injection pressure is not restricted, and when the cleaning control is being executed, An engine control apparatus, characterized in that an injection time of the fuel injection valve is made shorter than when cleaning control is not executed . The cleaning control, the predetermined start condition is executed when satisfied, the suppressing means is tightened the start condition of the cleaning control than without suppressing cleaning control, suppress the cleaning control,
The engine control apparatus according to claim 1. The predetermined number of revolutions corresponds to the number of revolutions during idle operation of the engine.
The engine control apparatus according to any one of claims 1 to 2. A fuel injection valve provided such that a nozzle hole for fuel injection faces the combustion chamber;
Cleaning control means for performing cleaning control for increasing the injection pressure of the fuel injection valve in order to remove deposits attached to the injection hole;
An engine control device comprising:
The controller is
Determination means for determining whether or not the speed of a vehicle on which the engine is mounted is less than a predetermined speed;
Suppression means for limiting an increase in the injection pressure of the fuel injection valve in the cleaning control when it is determined that the speed of the vehicle is less than the predetermined speed ,
Further, the control device has an injection pressure setting means for setting a lower upper limit value when the injection pressure is increased in the cleaning control as the speed of the vehicle on which the engine is mounted is lower,
When the increase in the injection pressure is restricted, the fuel injection valve has a longer injection time than when the increase in the injection pressure is not restricted, and when the cleaning control is being executed, An engine control apparatus, characterized in that an injection time of the fuel injection valve is made shorter than when cleaning control is not executed .

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