JP2010038142A - Injection amount control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection amount control device for an internal combustion engine, can improve drivability and prevent an increase of a misfire rate by improving the correcting accuracy of a learning value for the aging deterioration of an injector. <P>SOLUTION: An ECU obtains a vehicle travel distance from a RAM (Step S11), and determines whether it is a learning timing for learning injection or not (Step S12). When determining that it is the learning timing (Yes in Step S12), it calculates a learning value KG1 (Step S13). Meanwhile, when determining that it is not the learning timing (No in Step S12) the ECU calculates a learning value difference ΔKG produced by a difference between a travel distance at a previous learning timing and a current travel distance in accordance with the pre-estimated deterioration trend of the injector (Step S15) and updates a learning value KG using a value obtained by adding the learning value difference ΔKG to the learning value KG1 (Step S16). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an injection amount control apparatus for an internal combustion engine, and in particular, learns the deterioration of the injection performance of a fuel injection valve of an in-vehicle internal combustion engine, and executes an actual injection amount control according to the injection performance. Relates to the device.

  In general, in an internal combustion engine mounted on a vehicle, in particular, a fuel that accumulates at a high pressure, such as a recent diesel engine, is divided into a plurality of times by a highly responsive injector and is injected in a very small amount (that is, an injection amount). An injection performance that accurately follows the amount of fuel actually injected from the injector, that is, the actual injection amount, with respect to a target injection amount such as pilot injection in which the command value is a minute value) is required.

  On the other hand, the injection accuracy of the injector with respect to the command injection amount, that is, the accuracy of injection amount control, gradually decreases with time. In view of this, there is a technique in which the degree of deterioration of the injection accuracy of the injector over time is grasped by learning processing, and the command injection amount to the injector is controlled so that a required actual injection amount is obtained.

As a conventional injection amount control device for this type of internal combustion engine, the difference between the amount of fuel injected so as to maintain the engine rotational speed at a predetermined rotational speed during idling and the injection amount command value for injecting this fuel is used. Based on the above, the degree of deterioration of the injector is calculated, and the learning value for correcting the injection amount command value is determined after excluding the influence of engine friction during running-in (see, for example, Patent Document 1).
JP 2002-89333 A

  However, in the conventional control device described in Patent Document 1 as described above, the command injection amount is corrected at the timing when the fuel injection amount is learned, but the injector between the learning timings is corrected. The progress of deterioration was not taken into consideration. Therefore, after calculating the learning value at a certain learning timing, the learning value is kept constant until the next learning timing, so the progress of the injector deterioration between the learning timings is not reflected in the learning value, and the correction accuracy for the command injection amount Was the cause of falling. As a result, there is a problem that drivability is deteriorated and a misfire rate may be increased.

  The present invention has been made to solve such a problem, and is a fuel injection amount control device capable of improving the correction accuracy of a learned value with respect to aging deterioration of an injector and preventing an improvement in drivability and an increase in misfire rate. The purpose is to provide.

  In order to achieve the above object, an internal combustion engine injection amount control apparatus according to the present invention is (1) mounted on a vehicle, generates an injection command signal for instructing the injector of the internal combustion engine to inject fuel, and the injector An injection amount control device for an internal combustion engine that executes a learning process for learning a change in fuel injection performance of the engine under preset learning conditions and corrects the injection command signal according to a result of the learning process, Rotational speed detection means for detecting the engine rotational speed of the internal combustion engine, learning injection command means for instructing the injector to perform injection for learning at a predetermined designated injection amount at a predetermined learning timing, and the learning injection command When the learning injection is performed by the injector according to a command from the means, the amount of change in the engine rotational speed of the internal combustion engine due to the learning injection is detected by the rotational speed detection. Performance value calculating means for calculating an injection performance value corresponding to the actual injection amount of the injector based on the change amount, and actual injection of the injector specified from the injection performance value A learning value calculating means for calculating a learning value for correcting the command injection amount in accordance with a difference between the amount and the command injection amount commanded to the injector, and deterioration with respect to a presumed integrated use amount of the injector Based on the trend, a deterioration degree estimating means for estimating the degree of deterioration of the injector that occurs in accordance with the increase in the accumulated usage amount from the learning timing of the injector from the deterioration trend, and from the learning timing to the next learning timing The learning value calculated by the learning value calculating means is estimated by the deterioration degree estimating means. A learning value correcting means for correcting in accordance with the degree of deterioration was, characterized by comprising a.

  With this configuration, even when the cumulative amount of use of the injector is other than the learning timing, the learning value can be corrected according to the degree of deterioration of the injector in the cumulative amount of use, so the learning frequency is set to be the same as the conventional one. In addition, the correction accuracy of the learning value for the aging deterioration of the injector is improved, and the improvement of the drivability and the increase in the misfire rate can be prevented.

  (2) An injection command signal mounted on a vehicle and commanding fuel injection to an injector of an internal combustion engine is generated, and a change in fuel injection performance of the injector is learned under preset learning conditions. An injection amount control apparatus for an internal combustion engine that executes a learning process and corrects the injection command signal according to a result of the learning process, and a rotation speed detection unit that detects an engine rotation speed of the internal combustion engine, and a preset value The learning injection command means for instructing the injector to perform the learning injection at the designated injection amount at a predetermined learning timing, and the learning injection is performed by the injector in response to a command from the learning injection command means. A change amount of the engine speed of the internal combustion engine due to the learning injection is calculated based on detection information of the rotation speed detection means, and based on the change amount, According to the difference between the performance value calculation means for calculating the injection performance value corresponding to the actual injection amount of the injector, and the commanded injection amount commanded to the injector and the actual injection amount of the injector specified from the injection performance value A learning value calculating unit that calculates a learning value for correcting the command injection amount, and a storage unit that stores the learning value calculated at the learning timing and the integrated usage amount of the injector at the learning timing in association with each other. A deterioration trend calculating means for calculating a deterioration trend with respect to the cumulative amount of use of the injector based on a change of the learned value stored in the storage means with respect to the cumulative amount of use of the injector; and the vehicle from the learning timing The degree of deterioration of the injector that occurs according to the increased amount of cumulative use of the injector The learning value calculated by the learning value calculation unit between the learning timing and the next learning timing is corrected by the deterioration level estimated by the deterioration level estimation unit between the learning timing and the next learning timing. Learning value correction means for performing the above-described operation.

  With this configuration, it is possible to improve the estimation accuracy of the degree of deterioration of the injector by calculating the deterioration trend of the injector based on the change in the learning value calculated at the learning timing. Therefore, even when the cumulative usage amount of the injector is other than the learning timing, by correcting the learning value according to the estimated degree of deterioration of the injector, the accuracy of the injection amount can be improved even if the learning frequency is set to be the same as the conventional one. This can be further improved.

  ADVANTAGE OF THE INVENTION According to this invention, the correction precision of the learning value with respect to aged deterioration of an injector can be improved, and a drivability improvement and the raise of a misfire rate can be prevented.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram showing an internal combustion engine injection amount control apparatus according to a first embodiment of the present invention and an entire fuel injection system including the same. In the present embodiment, a case where the internal combustion engine is configured by a four-cylinder diesel engine will be described. However, the present invention is not limited to a diesel engine, and for example, LPG (liquefied petroleum gas), LNG (liquefied natural gas), or the like. It may be constituted by an ignition type engine that uses other fuel, a gasoline engine, or the like. Further, the invention is not limited to the in-cylinder direct injection type engine, but may be a port injection type engine.

  The fuel injection system 1 is mounted on a vehicle. The fuel pumped up from a fuel tank 11 by a feed pump 12 is metered by a metering valve 13 which is a variable throttle element, and a pressure pump 15 is passed through a check valve 14. The high-pressure fuel pressurized by the pressurizing pump 15 is supplied to the common rail 17 through which the high-pressure pressure can be stored through the check valve 16. The fuel injection system 1 also supplies the fuel supplied to the common rail 17 from the injector 18 corresponding to the cylinder 2a in the compression stroke among the plurality of injectors 18 connected to the common rail 17, to the combustion chamber 2b in the cylinder 2a. The high-pressure injection is performed at a preset injection timing.

  A known pressure limiter 21 and a fuel pressure sensor 22 are mounted on the common rail 17. The pressurizing pump 15 is rotatably mounted on a pump housing 15h, a plunger 15p that can move back and forth in the radial direction of the pump housing 15h, a camshaft 15s that drives the plunger 15p, and an eccentric cam portion of the camshaft 15s. Cam ring 15r.

  Between the pump housing 15h and the plunger 15p, at least one pressurizing chamber 15a that performs the suction, pressurization, and discharge operations of the fuel by the reciprocating movement of the plunger 15p is defined. A camshaft 15s and a cam ring 15r are accommodated in the pump housing 15h. In addition, fuel is supplied from the metering valve 13 through the orifice 19a and the fuel discharged from the feed pump 12 is supplied through the orifice 19b.

  The fuel supplied excessively to the common rail 17 is discharged from the pressure limiter 21 and recirculates to the fuel tank 11. The discharge pressure of the feed pump 12 is limited to a set pressure or less by the relief valve 12r.

  The fuel injection system 1 also includes an ECU (Electronic Control Unit) 31 described later. The injector 18 has a solenoid valve portion 18a driven by an injection command signal Iq from the ECU 31 and a nozzle hole portion 18j exposed in the combustion chamber 2b of each cylinder 2a at the tip thereof, and when the solenoid valve portion 18a is energized, And a nozzle portion 18b that performs a valve opening operation so as to inject fuel into the cylinder 2a from the injection hole portion 18j. The injectors 18 are connected to the common rail 17 by high-pressure pipes 17p for each cylinder of the engine 2. Since the structure of such an injector 18 is known, it will not be described in detail here.

  Information detected by the fuel pressure sensor 22 mounted on the common rail 17 is output to an ECU 31 described later as a rail pressure in the common rail 17 and is compared with a target rail pressure set by the ECU 31. Then, the ECU 31 changes the opening of the fuel supply-side metering valve 13 by energization control so that the fuel pressure in the common rail 17 matches the target rail pressure.

  Although a specific hardware configuration is not illustrated, the ECU 31 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a backup memory configured by a nonvolatile memory, and A / D conversion. An input interface circuit including a device, an output interface circuit including a driver and a relay switch, and a low voltage circuit.

  In addition to the fuel pressure sensor 22, the ECU 31 includes a rotation speed sensor 23 (rotation speed detecting means) for detecting the rotation speed ω of the crankshaft 2c of the engine 2, that is, an engine speed, and a throttle opening sensor for detecting the throttle opening. 24, a sensor group such as a vehicle speed sensor 25 for detecting the vehicle speed of a vehicle (not shown) on which the engine 2 is mounted is connected.

  The ECU 31, in accordance with a control program stored in advance in the ROM, based on detection information of the sensor group and setting value information stored in advance in a backup memory, while further communicating with other in-vehicle ECUs, for example, The engine speed [rpm] of the engine 2 is detected from the detection information of the rotational speed sensor 23, the target rail pressure of the common rail 17 during operation of the engine 2 is set, and the injection timing and fuel according to the operating state of the engine 2 are set. The injection amount is calculated, and the opening adjustment signal Iv to the metering valve 13 and the injection command signal Iq to the electromagnetic valve 18a of the injector 18 are output in a timely manner.

  As will be described later, the ECU 31 is an internal combustion engine injection amount control apparatus, learning injection command means, performance value calculation means, learning value calculation means, deterioration degree estimation means, learning value correction means, and storage means according to the present invention. And a deterioration trend calculating means.

  Hereinafter, a characteristic configuration of the ECU constituting the injection amount control apparatus for an internal combustion engine according to the first embodiment of the present invention will be described.

  The ECU 31 constituting the injection amount control device of the engine 2 instructs the injector 18 to perform injection for learning with a preset designated injection amount at a predetermined learning timing. Therefore, ECU31 which concerns on this Embodiment comprises the injection instruction | command means for learning which concerns on this invention.

  The predetermined learning timing is determined according to the travel distance of the vehicle, and a distance map in which the learning timing is associated with the travel distance is stored in the ROM in advance. The travel distance associated with the learning timing is set to, for example, 500 km, 1000 km, 2000 km, and 4000 km in order from the first time. These values are corrected with sufficient frequency even if the deterioration trend of the injector 18 is worse than the average deterioration trend of the injector 18 (see, for example, the solid line 51 in FIG. 3 described later). The injection amount accuracy is determined to be within an allowable value.

  Further, when the ECU 31 controls the injector 18 to execute the learning injection to the combustion chamber 2b during the compression stroke of the specific cylinder, the ECU 31 rotates the increase amount (change amount) of the engine 2 of the engine 2 by the learning injection. The torque proportional amount (injection performance value) corresponding to the actual injection amount of the injector 18 is calculated based on the detection information of the number sensor 23 and based on the rotation increase amount. Therefore, the ECU 31 according to the present embodiment constitutes a performance value calculation unit according to the present invention.

  FIG. 2A is a graph showing the proportional relationship between the injection amount of learning injection and the generated torque executed by the injection amount control device for an internal combustion engine according to the first embodiment of the present invention. ) Is a graph showing the relationship between the amount of increase in the rotational speed by the learning injection and the engine rotational speed at the time of learning injection.

In the engine 2 which is a diesel engine, as shown in FIG. 2A, the fuel injection amount [mm ³ / st] and the torque [N · m] generated by the fuel injection in a relatively small injection amount range Are proportional to each other. Further, from the characteristics of the engine 2, the relationship between the engine speed and the amount of increase in the rotational speed due to a small amount of learning injection and the engine rotational speed of the learning injection amount is also stored in advance in the ROM as data indicating the correspondence as shown in FIG. You can remember it. Therefore, the ECU 31 first executes a single small amount of learning injection (hereinafter also referred to as single injection) under the non-injection operation in which the command injection amount to the injector 18 is zero or less, and the engine by the single injection The product of the amount of increase in the rotational speed and the engine rotational speed when the single injection is executed is calculated as a torque proportional amount. Since this torque proportional amount is proportional to the generated torque, the ECU 31 calculates the generated torque from the torque proportional amount and estimates the actual injection amount.

  Returning to FIG. 1, when the actual injection amount corresponding to the injection performance value is estimated, the ECU 31 learns the difference between the actual injection amount and the commanded injection amount commanded to the injector 18 as the deteriorated injection amount. Further, the ECU 31 corrects the command injection amount with a learned value so that the command injection amount and the actual injection amount coincide with each other, and outputs the corrected command injection amount as an injection command signal Iq. At this time, the ECU 31 calculates a learning value KG1 for correcting the command injection amount in accordance with the deteriorated injection amount. Therefore, the ECU 31 according to the present embodiment constitutes a learning value calculation unit according to the present invention.

  Further, the ECU 31 determines, based on the deterioration trend of the injector 18 with respect to the estimated usage amount of the injector, the degree of deterioration of the injector 18 that occurs according to the increase amount of the usage cumulative amount from the learning timing of the injector from the deterioration trend. Estimated. Note that the cumulative usage amount of the injector in the present invention means a cumulative value of the travel distance, travel time, or use time of the injector from the time when the injector 18 is installed in the vehicle. In the description of the present embodiment, it is assumed that the accumulated usage amount of the injector 18 is represented by the travel distance of the vehicle, and the increase amount of the accumulated usage amount corresponds to the increase amount of the travel distance of the vehicle. To do.

  FIG. 3 is a graph showing the deterioration trend and learning value of the injector with respect to the travel distance.

  A deterioration trend representing a tendency of a change in the deterioration injection amount of the injector 18 with respect to the travel distance is determined in advance by experimental measurement or the like. For example, as a result of measuring deterioration trends for a plurality of injectors, if the upper limit of the deterioration trend is represented by a solid line 51 and the lower limit is represented by a solid line 54, the average deterioration trend represented by the solid line 53 is estimated in advance. The deterioration trend of the injector 18 is stored in the ROM.

  Returning to FIG. 1, the ECU 31 estimates the degree of deterioration of the injector 18 based on the deterioration trend stored in the ROM and the travel distance from the previous learning timing.

  Specifically, the ECU 31 acquires the travel distance corresponding to the previous learning timing and the current travel distance. Further, the deterioration trend stored in the ROM is referred to, and the difference in the deteriorated injection amount of the injector 18 generated between the travel distance corresponding to the previous learning timing and the current travel distance, that is, the deterioration degree of the injector is calculated. .

  Therefore, the ECU 31 according to the present embodiment constitutes a deterioration degree estimating means according to the present invention.

  In addition, the ECU 31 corrects the learning value calculated as described above according to the travel distance between the current learning timing and the next learning timing. Specifically, a correction amount ΔKG for correcting the learning value is calculated according to the calculated deterioration degree of the injector 18, and the correction amount ΔKG is added to the learning value KG1 calculated at the learning timing. The ECU 31 updates the set learning value KG with the learning value KG1 corrected by the correction amount ΔKG.

  Therefore, the ECU 31 according to the present embodiment constitutes a learned value correction unit according to the present invention.

  The learning value KG is corrected based on the deterioration trend (see the solid line 53) between the learning timings as represented by the solid line 55 in FIG. In this case, the injection amount accuracy (see the solid line 56) falls within an error range between the average deterioration trend (see the solid line 53) and the actual deterioration trend of the injector 18 (see the solid line 52). Therefore, it is possible to take a sufficiently small value as compared with the compensated injection amount accuracy line even during the learning timing. The injection amount accuracy means a difference between an actual deteriorated injection amount in the injector 18 and a command injection amount that is increased by correction so that the deteriorated injection amount is offset. That is, the closer the solid line 56 is to zero, the higher the accuracy of the injection amount by correction. The compensated injection amount accuracy line represents an injection amount accuracy threshold at which the degree of exhaust gas purification and the misfire ratio falls within an allowable value.

  On the other hand, as shown in FIG. 3B, when the learning value KG is not corrected by the deterioration trend, the learning value KG is updated at the learning timing, but becomes a constant value between the learning timings (solid line). 61). Therefore, the injection amount accuracy reaches the vicinity of the compensation injection amount accuracy line immediately before each learning timing (see the solid line 62).

  FIG. 4 is a flowchart for explaining the learning value correction processing according to the first embodiment of the present invention.

  In addition, the following processes implement | achieve the program which can be processed by CPU while being performed by CPU which comprises ECU31 at predetermined time intervals.

  The ECU 31 first acquires the travel distance TD of the vehicle from the RAM (step S11). Specifically, the ECU 31 takes in the integrated value information of the travel distance from the use start time of the injector 18 into a specific memory area in the RAM used for the learning process. Moreover, ECU31 takes in the distance map which prescribes | regulates learning timing at the time of starting.

  Next, the ECU 31 determines whether or not it is the learning timing for performing the learning injection (step S12). Specifically, the ECU 31 compares the distance map that defines the learning timing captured at the time of start-up with the travel distance TD of the vehicle. As a result of the comparison, the ECU 31 learns that the travel distance TD of the vehicle is defined in the distance map. If the timing is reached, it is determined that it is the learning timing.

  If the ECU 31 determines that it is the learning timing (Yes in step S12), the ECU 31 proceeds to step S13. On the other hand, when it is determined that it is not the learning timing (No in step S12), the process proceeds to step S15.

  Next, the ECU 31 calculates a learning value KG1 in step S13. The learning value KG1 is calculated by executing a learning value calculation process described later.

  Next, the ECU 31 updates the learning value (step S14). Specifically, the ECU 31 updates the current learning value KG stored in the RAM with the learning value KG1 calculated by the learning value calculation process. Further, the ECU 31 stores the learned travel distance TD0 in the RAM.

  On the other hand, when the ECU 31 determines that it is not the learning timing in step S12, the ECU 31 calculates a learning value difference ΔKG based on the previously estimated deterioration trend of the injector 18 (step S15).

  Specifically, the ECU 31 acquires a deterioration trend stored in the ROM. Next, the ECU 31 calculates the difference between the travel distance TD acquired in step S11 and the distance TD0 where the previous learning was performed. Next, the ECU 31 refers to the acquired deterioration trend and acquires the travel distance TD0 and the deteriorated injection amount corresponding to the travel distance TD. Then, the ECU 31 calculates a value ΔKG that should correct the learning value KG1 according to the difference between these deteriorated injection amounts, that is, the degree of deterioration of the injector 18 that has occurred while the vehicle traveled from the previous learning timing to the present time. To do.

  Next, the ECU 31 adds the learning value difference KG calculated in step S15 to the learning value KG1 stored in the RAM, and updates the learning value KG with the corrected learning value KG1 (step S16).

  FIG. 5 is a flowchart for explaining learning value calculation processing according to the first embodiment of the present invention.

The ECU 31 first determines whether or not a learning execution condition for calculating the learning value KG1 is satisfied (step S21). Specifically, the ECU 31 determines whether or not the following conditions (a) to (c) are satisfied.
(A) When there is no injection when the injection command signal Iq of the injector 18 indicates the injection amount 0 (for example, at the time of deceleration fuel cut or shift change).
(B) The fuel pressure (rail pressure) in the common rail 17 is maintained within a certain range.
(C) The cooling temperature of the engine 2 exceeds a certain temperature.

  The ECU 31 performs learning based on signals input from sensors for detecting environmental conditions such as temperature sensors, pressure sensors, speed sensors, and the like, and sensors for detecting driver operation inputs such as a throttle opening sensor. The condition may be determined.

  When the ECU 31 determines that the learning execution condition is satisfied (Yes in step S21), the ECU 31 proceeds to step S22. On the other hand, when it is determined that the learning execution condition is not satisfied (No in step S21), the process proceeds to Return.

  Next, the ECU 31 carries out learning injection (step S22). Specifically, the ECU 31 outputs an injection command signal Iq representing a command injection amount stored in advance in the ROM to the injector 18 and performs learning injection. The command injection amount in the learning injection corresponds to, for example, a command injection amount when pilot injection is executed prior to main injection during normal operation of the engine 2.

  Next, the ECU 31 calculates a learning value for correcting the difference between the actual injection amount and the command injection amount caused by the aging deterioration of the injector 18 (step S23).

Specifically, the ECU 31 calculates the engine speed a plurality of times at regular time intervals based on the detected pulse information of the speed sensor 23 under a no fuel injection state (for example, a deceleration fuel cut state). The engine speed ω1 ′ immediately after the learning injection timing, which is estimated when there is no learning injection at the learning injection timing, is calculated by calculating a rotational speed fluctuation amount Δωd of the engine speed that gradually decreases under the condition. calculate. Then, the engine speed increase amount Δωj, which is the difference between the engine speed ω1 when there is a learning injection at the learning injection timing and the engine speed ω1 ′ when there is no learning injection, is calculated. Next, an injection performance value is calculated as a torque proportional amount which is the product of the rotational speed increase amount Δωj and the engine rotational speed ω ₀ at the time of learning injection.

  Next, the ECU 31 corrects the command injection amount from the deteriorated injection amount that is the difference between the actual injection amount of the injector 18 at the time of learning injection corresponding to the calculated torque proportional amount and the command injection amount commanded to the injector 18. A learning value KG1 as a power correction amount is calculated.

Specifically, from the relationship shown in FIG. 2 (a), the ECU 31 determines the actual injection amount of the injector 18 in the learning injection from the torque proportional amount (the generated torque (k · Δωj · ω ₀ : Is calculated from a proportional constant)). Then, a learning value KG1 as a correction amount for correcting the command injection amount is calculated from the deteriorated injection amount that is the difference between the calculated actual injection amount and the command injection amount commanded to the injector 18.

  Next, the ECU 31 determines whether or not the learning execution condition is continued (step S24). Specifically, the ECU 31 determines whether or not the learning execution condition is established in step S21.

  If the ECU 31 determines that the establishment of the learning execution condition continues (Yes in step S24), the ECU 31 holds the calculated learning value (step S25). On the other hand, when the ECU 31 determines that the establishment of the learning execution condition is not continued (No in step S24), the ECU 31 discards the learning value KG1 calculated in step S23 (step S26). In this case, the ECU 31 holds the learning value KG without updating it in step S14 of the learning value correction process.

  As described above, in the injection amount control apparatus for an internal combustion engine according to the first embodiment of the present invention, even when the vehicle travels a travel distance other than the learning timing, the injector 18 at the travel distance is Since the learning value can be corrected according to the degree of deterioration, even if the learning frequency is set to be the same as the conventional value, the correction accuracy of the learning value for the aging deterioration of the injector 18 can be improved, and the drivability and the misfire rate are increased. Can be prevented.

  In the above description, the ECU 31 describes the case where the deterioration trend of the injector 18 is stored in the ROM in advance. However, the present invention is not limited to this, as in the second embodiment described below. The ECU 31 may calculate the deterioration trend of the injector 18 based on the history of learned values.

(Second Embodiment)
An injection amount control apparatus for an internal combustion engine according to a second embodiment of the present invention will be described with reference to FIGS.

  The configuration of the injection amount control device for the internal combustion engine according to the second embodiment is substantially the same as the configuration of the injection amount control device for the internal combustion engine according to the first embodiment described above. These will be described using the same reference numerals as those in the first embodiment shown in FIG. 1, and only differences will be described in detail.

  When the ECU 31 calculates the learning value at the learning timing, the ECU 31 associates the calculated learning value with the cumulative usage amount of the injector at the learning timing, and stores them in the RAM as a storage unit. Further, the ECU 31 calculates a deterioration trend with respect to the usage cumulative amount of the injector 18 based on the change of the plurality of learning values stored in the RAM with respect to the cumulative usage amount of the injector 18. Therefore, the ECU 31 of the present embodiment constitutes a deterioration trend calculation means of the present invention.

  FIG. 6 is a flowchart for explaining the learning value correction processing according to the second embodiment of the present invention. In addition, the following processes implement | achieve the program which can be processed by CPU while being performed by CPU which comprises ECU31 at predetermined time intervals. The learning value correction process according to the second embodiment is substantially the same as the learning value correction process according to the first embodiment, and the differences will be particularly described in detail.

  Further, as described above, the cumulative amount of use of the injector in the present invention means a cumulative value of the travel distance, travel time, or use time of the injector from the time when the injector 18 is installed in the vehicle. Also in the description of the present embodiment, it is assumed that the accumulated usage amount of the injector 18 is represented by the travel distance of the vehicle, and the increase amount of the cumulative usage amount corresponds to the increase amount of the travel distance of the vehicle. To do.

  The ECU 31 first obtains the travel distance TD of the vehicle from the RAM (step S31). Moreover, ECU31 takes in the distance map which prescribes | regulates learning timing at the time of starting. Next, the ECU 31 compares the distance map that defines the learning timing with the travel distance TD of the vehicle, and determines whether or not the travel distance TD of the vehicle has reached the learning timing (step S32).

  When the ECU 31 determines that it is the learning timing (Yes in step S32), the ECU 31 proceeds to step S33. On the other hand, when it is determined that it is not the learning timing (No in step S32), the process proceeds to step S35.

  Next, the ECU 31 calculates a learning value KG1 in step S33. The learning value KG1 is calculated by executing the learning value calculation process.

  Next, the ECU 31 updates the currently set learning value KG with the learning value KG1 as in step S14 (step S34). Further, the learning value KG calculated in the current learning is stored in the RAM as a learning value history in association with the travel distance TD0.

  On the other hand, if the ECU 31 determines that it is not the learning timing in step S32, the ECU 31 calculates a deterioration trend of the injector 18 (step S35). Specifically, the ECU 31 calculates a deterioration trend with respect to the travel distance of the injector 18 by a known interpolation method based on the learned value history stored in the RAM. The calculated deterioration trend is stored in the RAM. It should be noted that the deterioration trend may be calculated at each learning timing.

  Next, the ECU 31 calculates a learning value difference ΔKG based on the calculated deterioration trend (step S36).

  Specifically, the ECU 31 acquires the deterioration trend calculated in step S35. Next, the ECU 31 calculates the difference between the travel distance TD acquired in step S31 and the distance TD0 where the previous learning was performed. Next, the ECU 31 refers to the acquired deterioration trend and acquires the travel distance TD0 and the deteriorated injection amount corresponding to the travel distance TD. Then, the ECU 31 calculates a value ΔKG that should correct the learning value KG1 according to the difference between these deteriorated injection amounts, that is, the degree of deterioration of the injector 18 that has occurred while the vehicle has traveled from the previous learning timing to the present time. To do.

  Next, the ECU 31 adds the learning value difference KG calculated in step S36 to the learning value KG1 stored in the RAM, and updates the learning value KG with this value (step S37).

  FIG. 7 is a graph showing a deterioration trend and a learned value of the injector according to the second embodiment of the present invention. The ECU 31 calculates the deterioration trend (see the solid line 74) based on the deterioration degree (points 71, 72, and 73) of the injector 18 calculated at the learning timing, so that the calculated deterioration trend is actually generated in the injector 18. It is almost consistent with the deterioration trend. Therefore, the learning value KG (see the solid line 75) is corrected based on a deterioration trend that is substantially equal to the deterioration trend actually occurring in the injector 18 even between the learning timings, so that the injection amount accuracy (see the solid line 76) is improved. It becomes possible to make it a sufficiently small value as compared with the compensation injection amount accuracy line. That is, the accuracy of the injection amount in the injector 18 can be increased.

  As described above, in the injection amount control apparatus for an internal combustion engine according to the second embodiment of the present invention, by calculating the deterioration trend of the injector 18 based on the change in the learning value calculated at the learning timing, the injector The estimation accuracy of the degree of deterioration of 18 can be improved. Therefore, even when the vehicle is traveling at a travel distance other than the learning timing, the learning value is corrected according to the estimated degree of deterioration of the injector 18, so that the injection is performed even if the learning frequency is set to be the same as the conventional one. The amount accuracy can be further improved.

  As described above, the injection amount control device for an internal combustion engine according to the present invention has the effect of improving the correction accuracy of the learned value for the aging deterioration of the injector, and improving the drivability and preventing the misfire rate from increasing. It is useful for an injection amount control device for an internal combustion engine mounted on a vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram illustrating an injection amount control device for an internal combustion engine according to a first embodiment of the present invention and an entire fuel injection system including the same. FIG. 2A is a graph showing the proportional relationship between the injection amount of learning injection and the generated torque executed by the injection amount control device for an internal combustion engine according to the first embodiment of the present invention. ) Is a graph showing the relationship between the amount of increase in the rotational speed by the learning injection and the engine rotational speed at the time of learning injection. FIG. 3 is a graph showing the deterioration trend and learning value of the injector with respect to the travel distance. It is a flowchart for demonstrating the learning value correction | amendment process which concerns on the 1st Embodiment of this invention. It is a flowchart for demonstrating the learning value calculation process which concerns on the 1st Embodiment of this invention. It is a flowchart for demonstrating the learning value correction | amendment process which concerns on the 2nd Embodiment of this invention. It is a graph which shows the deterioration trend and learning value of the injector which concern on the 2nd Embodiment of this invention.

Explanation of symbols

1 Fuel injection system 2 Engine (internal combustion engine)
2a Cylinder 11 Fuel tank 17 Common rail 18 Injector 22 Fuel pressure sensor 23 Rotational speed sensor (rotational speed detecting means)
31 ECU (injection quantity control device, learning injection command means, performance value calculation means, learning value calculation means, deterioration degree estimation means, learning value correction means, storage means, deterioration trend calculation means)

Claims (2)

An injection command signal mounted on a vehicle for instructing an injector of an internal combustion engine to inject fuel is generated, and a learning process for learning a change in fuel injection performance of the injector under a preset learning condition is executed. , An injection amount control device for an internal combustion engine that corrects the injection command signal according to a result of the learning process,
A rotational speed detecting means for detecting an engine rotational speed of the internal combustion engine;
Learning injection command means for instructing the injector to perform learning injection at a preset designated injection amount at a predetermined learning timing;
When the learning injection is performed by the injector in response to a command from the learning injection command means, the amount of change in the engine speed of the internal combustion engine due to the learning injection is based on detection information of the rotation speed detection means. A performance value calculating means for calculating an injection performance value corresponding to the actual injection amount of the injector based on the change amount;
Learning value calculating means for calculating a learning value for correcting the command injection amount according to a difference between an actual injection amount of the injector specified from the injection performance value and the command injection amount commanded to the injector; ,
Deterioration degree estimation means for estimating from the deterioration trend the degree of deterioration of the injector that occurs according to the amount of increase in the amount of accumulated use from the learning timing of the injector, based on a deterioration trend with respect to the accumulated amount of use of the injector estimated in advance. When,
Learning value correction means for correcting the learning value calculated by the learning value calculation means in accordance with the degree of deterioration estimated by the deterioration degree estimation means between the learning timing and the next learning timing. An injection amount control device for an internal combustion engine, characterized by comprising: An injection command signal mounted on a vehicle for instructing an injector of an internal combustion engine to inject fuel is generated, and a learning process for learning a change in fuel injection performance of the injector under a preset learning condition is executed. , An injection amount control device for an internal combustion engine that corrects the injection command signal according to a result of the learning process,
A rotational speed detecting means for detecting an engine rotational speed of the internal combustion engine;
Learning injection command means for instructing the injector to perform learning injection at a preset designated injection amount at a predetermined learning timing;
When the learning injection is performed by the injector in response to a command from the learning injection command means, the amount of change in the engine speed of the internal combustion engine due to the learning injection is based on detection information of the rotation speed detection means. A performance value calculating means for calculating an injection performance value corresponding to the actual injection amount of the injector based on the change amount;
Learning value calculating means for calculating a learning value for correcting the command injection amount according to a difference between an actual injection amount of the injector specified from the injection performance value and the command injection amount commanded to the injector; ,
Storage means for storing the learning value calculated at the learning timing and the accumulated usage amount of the injector at the learning timing in association with each other;
A deterioration trend calculating means for calculating a deterioration trend with respect to the cumulative amount of use of the injector based on a change of the learning value stored in the storage means with respect to the cumulative amount of usage of the injector;
Deterioration degree estimation means for estimating the degree of deterioration of the injector, which occurs according to the cumulative amount of use of the injector that the vehicle has increased from the learning timing, from the deterioration trend;
Learning value correction means for correcting the learning value calculated by the learning value calculation means by the deterioration degree estimated by the deterioration degree estimation means between the learning timing and the next learning timing; An injection amount control device for an internal combustion engine, characterized by:

Images