JP2002115592A - Abnormality handling device of stepping motor driven type throttle valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a abnormality handling device of a stepping motor driven type throttle valve capable of fully opening for abnormality detection or initialization with suitable frequency, in a diesel engine or the like. SOLUTION: When the throttle opening is within a saturated flow rate opening region calculated based on a saturated flow rate opening region map ('Yes' in S230), the throttle valve full opening check (Xta = 'ON') is executed (S270). That is, a condition where the throttle valve opening is forcibly driven up to the full-opening state is determined based on the saturated flow rate opening region calculated according to the opening state of the engine, instead of determining based on a specific opening of approximately full-opening state as a reference. The stepping motor is driven to fully open the throttle valve in a wider operating range than the conventional technique and without having influence on the operating state of the engine, such as emission. Accordingly, the problem is overcome.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality processing device for a step motor driven throttle valve.

[0002]

2. Description of the Related Art For example, since the output of a diesel engine is mainly controlled by controlling the fuel injection amount, conventionally, the demand for controlling the intake air amount has been low. However, in order to meet the increasing demand for emission improvement in recent years, it has become necessary to secure a large amount of EGR through a large amount of exhaust gas recirculation (hereinafter referred to as “EGR”). In order to secure the EGR amount, it is necessary to control the amount of intake air to the diesel engine itself. In order to control the intake air amount, a step motor-driven throttle valve capable of controlling the opening degree with high precision independently of the accelerator pedal without interlocking with the accelerator pedal has been proposed (Japanese Patent Laid-Open No. Hei 1 (1994) -107).
0-110633, JP-A-11-294197).

In such a step-motor-driven throttle valve, the number of steps required for rotating the step motor connected to the throttle valve shaft to the step position corresponding to the throttle opening to be realized is set. The opening degree control is performed by performing the drive output.
In order to accurately control the opening of the throttle valve, it is necessary that the step position of the step motor and the actual throttle opening always correspond correctly. However, there is a case where the step position and the throttle opening do not correspond accurately due to step-out of the step motor, sliding failure due to foreign matter accumulation, clogging or the like.

For this reason, in the above-mentioned prior art, a full-open switch is provided for switching the on / off state at the full-open position of the throttle valve, and a process is performed to drive the throttle valve to the full open when the diesel engine is operating. By setting the step position of the step motor at the time when the switch is turned on and off by the full opening process to a step position corresponding to the throttle opening at full opening, the correspondence between the throttle opening and the step position of the step motor is set. Has been initialized. Further, in the above-described prior art, during such initialization processing, an abnormality such as sticking of a throttle valve is detected based on whether or not a full-open switch is operated.

[0005]

As described above, when the intake air amount and the EGR rate change when the throttle valve is fully opened for abnormality determination and initialization during operation of the diesel engine, May adversely affect emissions. In order to prevent this change in the amount of intake air, in the above-described prior art, a throttle opening that is very close to full opening, which is almost the same as the amount of intake air in the fully open state, is set as a fixed reference opening, and is controlled by intake air amount control. When the throttle opening is larger than the reference opening, a full opening process for initialization and abnormality detection is performed.

[0006] However, depending on the operating condition of the diesel engine, it may be difficult to control the intake air amount to make the throttle opening very close to full open. If such a situation continues for a long time, there is almost no chance to execute the full opening process for abnormality detection and initialization, and it is possible to detect and initialize abnormalities such as sticking at an appropriate frequency. Disappears.

[0007] Conversely, depending on the operation state of the diesel engine, the throttle opening state that can be fully opened by intake air amount control may continue for a long time. In this case, the full-open process for initialization and abnormality detection is repeated at a high frequency, which may cause a problem in durability of the full-open switch.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an abnormality processing apparatus for a step motor driven throttle valve capable of performing full opening processing for abnormality detection and initialization at an appropriate frequency.

[0009]

The means for achieving the above object and the effects thereof will be described below. An abnormality processing apparatus for a throttle valve driven by a step motor according to claim 1, wherein the throttle valve of the internal combustion engine is driven to adjust the throttle opening, and the throttle valve is driven to drive the throttle valve to the internal combustion engine. And a throttle valve control means for setting a throttle opening according to the operating state of the throttle valve. Degree detection means, flow rate saturation opening area calculation means for obtaining a flow rate saturation opening area indicating an air flow rate substantially equal to the air flow rate at the limit opening degree according to the operation state of the internal combustion engine, and the flow rate saturation opening area Assuming that the throttle opening is within the flow rate saturation opening area calculated by the calculating means, Limit opening realizing means for driving the step motor so that the throttle opening becomes the limit opening when the opening realizing condition is satisfied; and a throttle opening obtained by the limit opening realizing means. When the stepping motor is driven so as to satisfy the above condition, there is provided abnormality determination means for determining an abnormality according to the detection content of the limit opening degree detection means.

When the throttle valve is to be opened to the limit opening, if the throttle opening at that time shows an air flow rate substantially equal to the air flow rate at the limit opening, the operation of the internal combustion engine is affected. It is possible to set the throttle valve to the limit opening without giving the pressure. Therefore, the flow rate saturation opening area calculation means obtains a flow rate saturation opening area indicating an air flow rate substantially equal to the air flow rate at the limit opening degree according to the operating state of the internal combustion engine. Then, when the limit opening realization condition that the throttle opening enters the flow rate saturation opening region is satisfied, the limit opening realizing means is:
The step motor can be driven such that the throttle opening reaches the limit opening without affecting the operation of the internal combustion engine. In this way, the throttle opening can be limited without affecting the operation of the internal combustion engine even in an operating state where it was not possible to forcibly set the limit opening due to the conventional determination based on the fixed reference opening. The opening can be adjusted. For this reason, it is possible to prevent the throttle opening from being unable to reach the limit opening for a long period of time, and it is possible to detect an abnormality by driving the step motor so that the throttle opening reaches the limit opening at an appropriate frequency. .

According to a second aspect of the present invention, in the abnormality processing apparatus for a step motor driven throttle valve according to the first aspect, the means for achieving the limit opening degree is such that load fluctuation and rotation speed fluctuation of the internal combustion engine are within a stable range. And that the throttle opening is within the flow rate saturation opening area calculated by the flow rate saturation opening area calculation means as the limit opening realization condition, and the limit opening realization condition is satisfied Preferably, the step motor is driven so that the throttle opening reaches the limit opening.

It is to be noted that the limit opening realizing means includes that the load fluctuation and the rotational speed fluctuation of the internal combustion engine are within the stable range, and that the throttle opening is within the flow saturation opening area calculated by the flow saturation opening area calculating means. The fact that the opening has entered may be used as the limit opening realization condition. Thus, the stepping motor can be driven such that the throttle opening becomes the limit opening when the limit opening realizing condition is stably satisfied.
Therefore, the possibility that the flow rate saturation opening region is reduced while the throttle opening is set to the limit opening is reduced, and the adverse effect on the operation of the internal combustion engine can be effectively prevented.

According to a third aspect of the present invention, in the abnormality processing device for a step motor driven throttle valve, the limit opening realizing means is calculated by the flow rate saturated opening area calculating means. Assuming that the state in which the throttle opening is within the flow rate saturation opening area has continued for the reference time is the limit opening realization condition, the throttle opening becomes the limit opening when the limit opening realization condition is satisfied. And the step motor is driven.

The limit opening realizing means determines that the state in which the throttle opening is within the flow rate saturated opening area calculated by the flow rate saturated opening area calculating means has continued for the reference time. It is good. Thus, the stepping motor can be driven such that the throttle opening becomes the limit opening when the limit opening realizing condition is stably satisfied. Therefore, the possibility that the flow rate saturation opening region is reduced while the throttle opening is set to the limit opening is reduced, and adverse effects on the operation of the internal combustion engine can be effectively prevented.

According to a fourth aspect of the present invention, there is provided a stepping motor drive type throttle valve abnormality processing apparatus, wherein the limit opening degree realizing means is configured such that load fluctuation and rotation speed fluctuation of the internal combustion engine are within a stable range. And the condition that the throttle opening is within the flow rate saturation opening area calculated by the flow rate saturation opening area calculation means for a reference time has been defined as the limit opening realization condition. When the realization condition is satisfied, the step motor is driven so that the throttle opening becomes the limit opening.

Further, the load fluctuation and the rotation speed fluctuation of the internal combustion engine are within the stable range, and the state where the throttle opening falls within the flow rate saturation opening area calculated by the flow rate saturation opening area calculation means. The fact that the reference time has been continued may be used as the limit opening degree realization condition. Thus, the stepping motor can be driven so that the throttle opening becomes the limit opening when the limit opening realizing condition is more stably satisfied. Therefore, it is possible to more reliably prevent the flow rate saturation opening region from being reduced while the throttle opening is set to the limit opening, and it is possible to more reliably prevent the adverse effect on the operation of the internal combustion engine.

According to a fifth aspect of the present invention, in the abnormality processing apparatus for a step motor driven throttle valve, the abnormality determination means determines the abnormality in one internal combustion engine operation period with respect to the configuration according to any one of the first to fourth aspects. A limit opening realization prohibiting unit that prohibits the processing by the limit opening realizing unit when the reference number of times has been reached.

As described above, it is sufficient that the determination by the abnormality determining means is performed the reference number of times in one internal combustion engine operation period, and thereafter, it is not necessary to repeatedly determine the abnormality during the same operation period. Accordingly, when the determination by the abnormality determination means is made a reference number of times during one internal combustion engine operation period, the limit opening realization prohibiting means prohibits the processing of the limit opening realizing means, so that it becomes more frequent than necessary. Thus, the opening of the throttle valve does not change to the limit opening.
Since the processing of the limit opening degree realizing means is executed at an appropriate frequency in this way, the limit opening degree detecting means does not function more than necessary, and the durability of the limit opening degree detecting means can be improved.

According to a sixth aspect of the present invention, in the abnormality processing device for a step motor driven throttle valve, the abnormality judging means in one operation period of the internal combustion engine is different from the configuration according to any one of the first to fourth aspects. The limit opening realization prohibiting means for prohibiting the processing of the limit opening realizing means when either of the case where the determination of the reference number of times is performed and the case where the determination that it is not abnormal is performed the reference number of times is satisfied. It is characterized by having.

For example, if the abnormality determination means determines that there is no abnormality in a single operation period of the internal combustion engine for a reference number of times, for example, once, it may be sufficient to perform the abnormality determination at the next operation. In some cases, it is necessary to execute the determination that the abnormality is abnormal by the abnormality determination means in a single internal combustion engine operation period, for example, twice, to confirm that the abnormality is reliable. For such a case, a reference number of times may be provided for each of the cases where the determination by the abnormality determination unit is abnormal and the case where the determination is not abnormal in one internal combustion engine operation period. Further, for example, when the normality is determined, the number of times determined to be abnormal may be cleared (initialized). As a result, the processing of the limit opening degree realizing means is executed at an appropriate frequency, so that the limit opening degree detecting means does not function more than necessary, and the durability of the limit opening degree detecting means can be improved. The judgment itself becomes more accurate.

According to a seventh aspect of the present invention, in the abnormality processing apparatus for a throttle valve driven by a step motor, according to any one of the first to fourth aspects, after the processing by the limit opening realizing means is performed, It is characterized in that a limit opening realization prohibiting means for prohibiting the processing of the limit opening realizing means until time elapses is provided.

As described above, the processing of the limit opening realizing means is prohibited until the reference time elapses by the limit opening realizing prohibiting means. It is possible to prevent the processing of the degree realizing means from being performed frequently and to set the frequency to an appropriate frequency. Thereby, the durability of the limit opening degree detecting means can be improved.

According to an eighth aspect of the present invention, in the abnormality processing apparatus for a step motor driven throttle valve, at least after the processing of the limit opening realizing means is performed on the configuration according to any one of the first to fourth aspects, Once, a limit opening realization prohibiting means for prohibiting the processing of the limit opening realizing means until the limit opening realizing condition is not satisfied and the reference time has elapsed is provided.

Further, even if the abnormality is determined again while the conditions for realizing the limit opening degree continue to be satisfied, it is considered that there is no significant change in the situation, and it is considered that the possibility of occurrence of the abnormality is small. Therefore, after the processing of the limit opening realizing means is performed by the limit opening realization prohibiting means, the processing of the limit opening realizing means is not performed until the limit opening realizing condition is not satisfied at least once and the reference time has elapsed. Prohibition. As a result, unnecessary processing by the limit opening degree realizing means can be reduced to an appropriate frequency, and the durability of the limit opening degree detecting means can be improved.

According to a ninth aspect of the present invention, there is provided a step motor driving type throttle valve abnormality processing apparatus for driving a throttle valve of an internal combustion engine to adjust a throttle opening, and for driving the throttle motor by driving the step motor. And a throttle valve control means for setting a throttle opening in accordance with an operation state of the internal combustion engine. A limit opening detecting means for performing the throttle opening, and setting the throttle opening close to the limit opening as a limit opening realizing condition. A limit opening realizing means for driving the step motor so as to obtain a throttle opening, and a throttle opening by the limit opening realizing means. There the abnormality determining means that in case of driving the stepping motor so as to limit opening, to determine an abnormality in accordance with the detected result of the limit opening detection means,
After the processing of the limit opening realizing means is performed, a limit opening realization prohibiting means for prohibiting the processing of the limit opening realizing means until a reference time has elapsed is provided.

The condition for realizing the limit opening may be that the throttle opening is close to the limit opening without obtaining the flow rate saturation opening region according to the operating state of the internal combustion engine.
In this case, the limit opening realizing means drives the step motor so that the throttle opening becomes the limit opening when the limit opening realizing condition is satisfied, but the limit opening realizing prohibiting means is the limit opening realizing means. After the above processing is performed, the processing of the limit opening realizing means is prohibited until the reference time has elapsed. As a result, when the conditions for realizing the limit opening are continuously established for a long time, it is possible to prevent the processing of the limit opening realizing means from being performed frequently and to set an appropriate frequency. Can be improved in durability.

According to a tenth aspect of the present invention, in the configuration of the ninth aspect, the limit opening degree realizing means is such that the load and the rotational speed of the internal combustion engine are within a reference range. And that the throttle opening is close to the limit opening as a limit opening realizing condition, and when the limit opening realizing condition is satisfied, the throttle opening becomes the limit opening. The step motor is driven.

The limit opening realizing means may use the condition that the throttle opening is close to the limit opening in an operating state in which the load and the rotation speed of the internal combustion engine are within the reference range as the limit opening realizing condition. Thus, the stepping motor can be driven such that the throttle opening becomes the limit opening when the limit opening realizing condition is stably satisfied. Therefore, the possibility that the flow rate saturation opening region is reduced while the throttle opening is set to the limit opening is reduced, and adverse effects on the operation of the internal combustion engine can be prevented.

According to an eleventh aspect of the present invention, in the abnormality processing device for a step motor driven throttle valve, in the configuration of the ninth or tenth aspect, the limit opening realization prohibiting means performs the processing of the limit opening realizing means. After that, the limit opening realizing condition is not satisfied at least once, and the processing of the limit opening realizing means is prohibited until the reference time elapses.

Even if the abnormality is determined again while the conditions for realizing the limit opening degree continue to be satisfied, it is considered that there is no significant change in the situation, and it is considered that the possibility of an abnormality is small.
Therefore, after the processing of the limit opening realizing means is performed by the limit opening realization prohibiting means, the processing of the limit opening realizing means is prohibited until the limit opening realizing condition is not satisfied at least once and the reference time has elapsed. are doing. As a result, unnecessary processing by the limit opening degree realizing means can be reduced to an appropriate frequency, and the durability of the limit opening degree detecting means can be improved.

According to a twelfth aspect of the present invention, there is provided a stepping motor driven throttle valve abnormality processing apparatus.
In the configuration according to any one of the above, the abnormality determination means,
When the stepping motor is driven so that the throttle opening becomes the limit opening by the limit opening realizing means, the limit opening detecting means detects that the throttle valve has reached the limit opening. If not, it is determined to be abnormal.

If the throttle valve is not detected to have reached the limit opening even though the stepping motor is driven so that the throttle opening reaches the limit opening, for example, the sticking of the throttle valve may occur. Since it is considered to have occurred, it can be determined that a failure has occurred.

According to a thirteenth aspect of the present invention, there is provided an abnormality processing apparatus for a throttle valve driven by a step motor.
In the configuration according to any one of the above, when the stepping motor is driven so that the throttle opening becomes the limit opening by the limit opening realizing means instead of the abnormality determination means, the limit opening detecting means And an initialization means for initializing the throttle opening as a throttle opening corresponding to the limit opening when it is detected that the throttle valve has reached the limit opening.

By providing initialization means in place of the abnormality determination means, when the stepping motor is driven by the limit opening realizing means so that the throttle opening becomes the limit opening, the limit opening detecting means is provided. When it is detected that the throttle valve reaches the limit opening, the throttle opening may be initialized as a throttle opening corresponding to the limit opening. By doing so, the step motor can be driven and initialized so that the throttle opening reaches the limit opening at an appropriate frequency.

According to a fourteenth aspect of the present invention, there is provided a stepping motor driven throttle valve abnormality processing apparatus.
In the configuration according to any one of the above, when the step motor is driven such that the throttle opening is the limit opening by the limit opening realizing means, the throttle valve is detected by the limit opening detecting means. When the limit opening is detected, initialization means is provided for initializing the throttle opening as a throttle opening corresponding to the limit opening.

Note that an initialization means may be provided together with the abnormality determination means. Thus, the abnormality determination and the initialization can be executed together by driving the step motor so that the throttle opening reaches the limit opening at an appropriate frequency.

According to a fifteenth aspect of the present invention, there is provided a stepping motor driven throttle valve abnormality processing apparatus.
Wherein the internal combustion engine is a diesel engine, and the limit opening is in a fully open state.

As described above, in particular, by utilizing the abnormality determination and initialization of the throttle valve of the diesel engine, the step motor is driven at an appropriate frequency so that the throttle opening is fully opened, and the abnormality determination and initialization are performed. Can be performed.

[0039]

[First Embodiment] FIG. 1 is a schematic configuration diagram of a diesel engine (hereinafter abbreviated as "engine") 2 to which the above-described invention is applied and a control system thereof. The engine 2 is mounted on an automobile for driving the automobile. An intake passage 4 is connected to the combustion chamber 3 of the engine 2 via an intake valve (not shown). An air cleaner 6 for filtering intake air, a pressure sensor 8 for detecting a pressure (atmospheric pressure) of the intake air, an intake temperature sensor 10 for detecting a temperature of the intake air, A throttle valve 14 for adjusting the amount of intake air introduced into the combustion chamber 3 is provided.

The throttle valve 14 is driven to open and close by a drive mechanism 16. The drive mechanism 16 is mainly configured by a step motor 18 and a gear group that drives and connects the step motor 18 and the throttle valve 14. The step motor 18 is provided with an electronic control unit (hereinafter referred to as “ECU”) 2 for performing various controls of the engine 2.
The drive is controlled by 0. Further, the drive mechanism 16 is provided with a full-open switch 22 that is turned on when the throttle valve 14 is at the full-open position.

On the other hand, an exhaust passage 24 is connected to the combustion chamber 3 via an exhaust valve (not shown). An EGR (exhaust gas recirculation) passage 26 that branches off from the exhaust passage 24 and joins the intake passage 4 is connected to the intake passage 4 on the downstream side of the throttle valve 14. This EGR passage 26
Is provided with an EGR control valve 30 that is opened and closed by an actuator 28 such as a diaphragm controlled by the ECU 20. By adjusting the intake air amount by the throttle valve 14 and the EGR amount by the EGR control valve 30, the EGR rate, which is the ratio of the EGR amount to the intake air amount introduced into the combustion chamber 3, can be freely set. It becomes possible. As a result, appropriate EGR over the entire operation range of the engine 2 is achieved.
Control can be performed.

A fuel injection nozzle 32 for injecting fuel is provided in the sub combustion chamber 3a of the engine 2. The fuel injection nozzle 32 is connected to a fuel injection pump 34. The fuel injection pump 34 is driven based on the rotation of the output shaft 2 a of the engine 2 and is driven by the fuel injection nozzle 32.
Pressurized fuel. The fuel injection pump 34
Is provided with a timer control valve 34a and a spill valve 34b for adjusting the injection timing and injection amount of the fuel injected from the fuel injection nozzle 32. These timer control valve 34a and spill valve 34b are also E
The operation is controlled by the CU 20. A rotor (not shown) that rotates in synchronization with the rotation of the output shaft 2a of the engine 2 is provided in the fuel injection pump 34, and a protrusion formed on the outer peripheral surface of the rotor is detected to rotate the rotor. A rotation speed sensor 36 including an electromagnetic pickup that outputs a pulse signal corresponding to the speed is provided.
The output of the rotation speed sensor 36 is taken into the ECU 20 as a signal that contributes to the calculation of the rotation speed of the engine 2.

The ECU 20 also stores accelerator opening information (accelerator pedal information) detected by an accelerator opening sensor 38, such as atmospheric pressure information detected by the pressure sensor 8 and intake air temperature information detected by the intake air temperature sensor 10. Information on the amount of depression of the engine), on / off information of the IG (ignition) switch 40, on / off information of the starter switch 42, cooling water temperature information detected by the cooling water temperature sensor 44 provided in the cylinder block 2b, and the like. It is being taken in.

Next, details of the drive mechanism 16 for opening and closing the throttle valve 14 will be described with reference to FIGS. 2 is a side sectional view of the throttle valve 14 and its driving mechanism 16, FIG. 3 is a front view of the driving mechanism 16, and FIG. 4 is a driven gear 16 provided in the driving mechanism 16.
2A and a partial cross-sectional structure of a peripheral portion thereof.

As shown in FIG. 2, a throttle valve 14 for changing the opening area of the intake passage 4 and adjusting the amount of intake air flowing through the intake passage 4 is fixed to a valve shaft 14a so as to be integrally rotatable. Have been. The valve shaft 14a is rotatably supported by a throttle body 14b connected to the intake passage 4. One end (the upper end in FIG. 2) of the valve shaft 14a is connected to the throttle body 14b via a return spring 14c. The return shaft 14a and the throttle valve 14
The throttle valve 14 is urged in a direction to open the throttle valve 14 by the urging force c.

At the other end (lower end in FIG. 2) of the valve shaft 14a,
Gearbox 16 mounted on throttle body 14b
The driven gear 16a provided in the inside b is attached so as to be able to rotate integrally. The driven gear 16a meshes with a second intermediate gear 16d rotatably supported by a support shaft 16c provided in the gear box 16b. The support shaft 16c
Is mounted with a first intermediate gear 16e that rotates integrally with the second intermediate gear 16d. This first intermediate gear 1
Reference numeral 6e meshes with a drive gear 18b attached to the output shaft 18a of the step motor 18 mounted on the gear box 16b so as to be integrally rotatable. That is, the rotation of the output shaft 18a driven by the step motor 18 is controlled by the drive gear 18b, the first intermediate gear 16e, and the second intermediate gear 16d.
And transmitted to the valve shaft 14a via the driven gear 16a. The rotation of the valve shaft 14a drives the throttle valve 14 to open and close.

As shown in FIG. 3, a lever 14f having two arms 14d and 14e is rotatably mounted on the valve shaft 14a. The lever 14f is connected to the driven gear 16a via a relief spring 14g. The lever 14f is biased against the driven gear 16a in the counterclockwise direction in FIG. 3 by the biasing force of the relief spring 14g. Also, lever 1
One arm 14e provided in 4f is bent in an L shape and extends toward the driven gear 16a. The distal end of the arm 14e is connected to a driven gear 16a as shown in FIG.
Is engaged in the groove 16f formed in the groove. And
The lever 14f is relatively rotatable with respect to the driven gear 16a by a gap between the groove 16f and the tip of the arm 14e. However, usually, the tip of the arm 14e is
The urging force of the relief spring 14g abuts the side wall of the groove 16f on the counterclockwise side around the valve shaft 14a. In this state, the driven gear 16a
And the lever 14f are integrally rotated.

At the tip of the other arm 14d provided on the lever 14f, there is provided a pressing portion 46 which can come into contact with the fully open switch 22 provided in the gear box 16b. The pressing portion 46 is a throttle valve 1
In the fully open position 4, it is possible to contact the fully open switch 22 and turn on the fully open switch 22.

In addition, a fully closed stopper (not shown) is provided. The fully closed stopper comes into contact with the lever 14f at a position where the throttle valve 14 is in the fully closed position, and further restricts the rotation of the throttle valve 14 in the closing direction.

The ECU 20 is mainly composed of a microcomputer. That is, a ROM that stores various control programs for fuel injection amount control, fuel injection timing control, EGR control, intake air amount control, etc. of the engine 2, maps for calculating values corresponding to various conditions, and the like. A CPU for executing arithmetic processing based on a program stored in the RAM, a RAM for temporarily storing an arithmetic result of the CPU and data input from each sensor, etc., and storing necessary data when power supply to the ECU 20 is cut off. And a backup RAM for holding the same. These C
The PU, the ROM, the RAM, and the backup RAM are connected to each other via a bus, and are also connected to an external input circuit and an external output circuit provided in the ECU 20. The above-described pressure sensor 8, intake air temperature sensor 10, fully open switch 22, rotation speed sensor 36, accelerator opening sensor 38, IG switch 40, starter switch 42, cooling water temperature sensor 44, etc.
The signal is converted into a signal suitable for processing inside and used for internal processing. In addition, the step motor 18, the actuator 28, the timer control valve 34a, the spill valve 34b, and the like are driven via an external output circuit according to the calculation result in the ECU 20.

Next, in the present embodiment, the ECU 20
A control process for the throttle valve opening degree among the controls executed by the control will be described. FIG. 5 shows a flowchart of the throttle valve opening control process executed by the ECU 20. This processing is repeatedly executed in a time cycle. Steps in the flowchart corresponding to each processing content are represented by “SＳ”.

When the present process is started, it is first determined whether or not a later-described full-open confirmation execution flag Xta is "OFF" (S110). If Xta = “ON” (“NO” in S110), since the later-described throttle valve full-open confirmation process has been executed, this process is temporarily ended. Note that E
Initially, when the power of the CU 20 is turned on, Xta =
It is set to “OFF”.

If Xta = “OFF” (“YES” in S110), the opening degree of the throttle valve 14 necessary for realizing an appropriate intake air amount and an EGR rate according to the operating state of the engine 2 is determined. Is calculated (S120). The operating state of the engine 2 includes, for example, an engine speed NE detected by the speed sensor 36 and an engine load (such as a fuel injection amount Q pumped from the fuel injection pump 34). The target step position is calculated based on a map or the like using the values such as the engine speed NE and the fuel injection amount Q.

Next, a drive output from the current step position to the target step position is output to the step motor 18 (S130). Thus, the opening of the throttle valve 14 is adjusted to a suitable opening according to the operating state of the engine 2. Thus, the present process is temporarily ended.

Next, the flowchart of FIG. 6 shows the full open confirmation process start determination process. This processing is repeatedly executed in a time cycle. When the process is started, first, it is determined whether or not the abnormality detection completion counter Cab is less than the abnormality detection completion reference number A (S210). If Cab <A (“YES” in S210), it is then determined whether the normal detection completion counter Cnr is less than the normal detection completion reference number B (S22).
0). If Cnr <B (“YES” in S220),
Next, from the flow rate saturation opening area map shown in FIG. 7, the flow rate saturation limit step position θL is determined based on the operating state of the engine 2, here, the engine load (specifically, the fuel injection amount Q) and the engine speed NE. The flow rate saturation opening area (flow rate saturation limit step position θL to fully open step position) is set (S225). The flow rate saturation opening area map shown in FIG. 7 shows a step position on the most closed side that shows a flow rate substantially equal to the intake flow rate in the intake path 4 when the throttle valve 14 is fully opened. θL
Is obtained in advance by an experiment using the fuel injection amount Q and the engine speed NE as parameters.

As shown in FIG. 8, the relationship between the step position and the air flow rate indicates that, depending on the operation state of the engine 2, the flow saturation limit step position θL sometimes indicates the step position θL1 close to full open as shown by the solid line. As shown by the one-dot chain line or the two-dot chain line, the step positions θL2 and θL3 farther than the fully open position may be shown. Therefore, the flow rate saturation opening region θsat, that is, the throttle valve 14
Regardless of the degree of opening, the step position region where the air flow rate remains substantially the same as the fully open state becomes narrower or wider depending on the operating state of the engine 2. In step S225, the flow rate saturation opening area θsat is set as an area between the flow rate saturation limit step position θL obtained from the map and the fully open step position.

Next, it is determined whether or not the full opening confirmation execution condition (corresponding to the limit opening realization condition) is satisfied (S2).
30). Here, the full-open confirmation execution conditions are the following three conditions. That is, “(1) The throttle opening θstep represented by the step position is within the flow saturation opening region θsat obtained from the flow saturation opening region map shown in FIG.
(2) The ECU according to the detection value of the accelerator opening sensor 38
The variation ΔQ of the fuel injection amount Q calculated inside the engine 20 is equal to or less than the reference value Qa, and (3) the variation ΔNE of the engine speed NE detected by the rotation speed sensor 36 is the reference value NE.
a or less. " The conditions (2) and (3) determine that the engine 2 is in a stable operation state.

If at least one of the above conditions (1) to (3) is not satisfied, it is determined that the fully open confirmation execution condition is not satisfied ("NO" in S230), and then the value of the condition satisfaction counter Tc is cleared to zero. (S240), and this process is once ended.

If all of the above conditions (1) to (3) are satisfied, it is determined that the condition for executing the full-open check has been satisfied ("YES" in S230), and then the condition satisfaction counter Tc
Is determined to have exceeded a time reference value C for determining stable operation continuation (S250). At first, Tc
Since (= 0) <C (“NO” in S250), the condition satisfaction counter Tc is then incremented (S26).
0), the process is once ended.

Thereafter, steps S210, S220, S2
As long as the condition of 30 is satisfied and Tc ≦ C (S25
0 ("NO"), the process of incrementing the condition satisfaction counter Tc (S260) continues.

Then, when Tc> C is satisfied ("YES" in S250), "ON" is set in the full-open confirmation execution flag Xta (S270), and the present process is ended once. Thereafter, even if the condition for executing the full-open confirmation in step S230 is not satisfied, the full-open confirmation execution flag Xta remains "ON" until the full-open confirmation execution flag Xta is set to "OFF" at the end of the later-described throttle valve full-open confirmation processing. To maintain. Further, since Xta = “ON”, substantial processing is not executed in the processing of the above-described throttle valve opening control processing (FIG. 5).

Next, "O" is set in the full-open confirmation execution flag Xta.
FIG. 9 shows a throttle valve fully open confirmation process for performing a substantial process when "N" is set. This processing is repeatedly executed in a time cycle.

When this processing is started, first, Xta = “O
N "is determined (S310). Xta = “OF
If "F"("NO" in S310), the present process is temporarily ended as it is. Therefore, if “ON” is not set to Xta in the full-open confirmation processing start determination processing (FIG. 6), the substantial processing is not performed in this processing.

In the full open confirmation process start determination process (FIG. 6), X
When “ON” is set to ta, Xta = “O”
N "(" YES "in S310), the current step position, that is, the number of steps from the current throttle opening to the full opening is obtained, and the drive output corresponding to this number of steps plus the increase step α is obtained. Is set (S32
0). The increase step α is the number of steps that are added to simply provide a drive output that is somewhat larger than the difference between the current step position and the step position at the time of full opening in consideration of the step-out of the step motor 18. With this drive output setting, the step motor 18 is driven in a direction to fully open the throttle valve 14 by a step motor drive process (not shown). At this time, although the throttle opening changes, as shown in FIG. 8, since the throttle opening changes within the flow rate saturation opening area θsat, the air flow rate itself is kept substantially constant. Therefore, the throttle valve 14 can be moved to the fully open position without substantially changing the intake air amount.

Next, it is determined whether or not the full-open switch 22 has been turned "ON" (S330). Switch 2 still open
2 is not “ON” (“N” in S330).
O "), it is determined whether the drive output set in step S320 has been completed (S340). While the drive output is not completed ("NO" in S340), the present process is temporarily terminated as it is.

If the full-open switch 22 is turned "ON" before the drive output is completed ("YES" in S330),
Next, the fully open step position is set as the current step position, and initialization is performed when the step-out occurs (S35).
0). Then, it is determined that it is not abnormal, that is, normal (S360). Further, the normal detection completion counter Cnr is incremented (S370). The normal detection completion counter Cnr is initialized to “0” each time the operation of the engine 2 is started by an initialization process when the power of the ECU 20 is turned on by the IG switch 40. Next, "OFF" is set for the full-open confirmation execution flag Xta (S38).
0), the process is once ended. Thus, Xta = “O
By returning to "FF", substantial processing is restarted in the processing of the throttle valve opening control processing (FIG. 5), and substantial processing is not performed in the throttle valve fully open confirmation processing (FIG. 9).

On the other hand, if the drive output is completed before the fully open switch 22 is turned "ON"("YES" in S340),
Since it is considered that an abnormality such as the sticking of the throttle valve 14 has occurred, it is determined that the abnormality is abnormal (S390). Then, the abnormality detection completion counter Cab is incremented (S400). Note that the abnormality detection completion counter Cab indicates I
The initialization is performed when the power of the ECU 20 is turned on by the G switch 40, and is initialized to “0” every time the operation of the engine 2 is started. Next, "OFF" is set to the full-open confirmation execution flag Xta (S380), and the present process is ended once.

Here, for example, the normal detection completion reference number B
Is "1", the normal detection completion counter Cnr becomes 1 once it is determined to be normal in step S360. Therefore, in step S220 of the fully open confirmation processing start determination processing (FIG. 6), NO "is determined. The reason why the normal detection completion counter Cnr is cleared to “0” as described above is due to the initialization at the time of starting the engine 2, and therefore, in the current operation period, the full-open confirmation execution flag Xta is set to “ON” again. And the substantial processing of the throttle valve fully open confirmation processing (FIG. 9) is not performed again.

Further, for example, if the value of the reference number A of abnormality detection completion is "2", the abnormality detection completion counter Cab = 1 even if the abnormality is once determined in step S390. Step S of the judgment processing (FIG. 6)
At 210, it is still determined to be "YES". For this reason,
Again, the full-open confirmation execution flag Xta can be set to “ON”, and the substantial processing of the throttle valve fully-open confirmation processing (FIG. 9) may be performed. Therefore, the substantial processing of the throttle valve fully open confirmation processing (FIG. 9) is performed. If it is determined again that the abnormality is abnormal in step S390, the abnormality detection completion counter Cab = 2, and “NO” is determined in step S210. Will be determined. As described above, the abnormality detection completion counter Cab is cleared to "0" because the initialization at the start of the engine 2 is performed. Therefore, in the current operation period, the throttle valve fully open confirmation processing (FIG. 9) is performed for the third time. Is not done. The reason why the determination is stopped when the abnormality is determined twice as described above is that the abnormality of the engine 2 must be controlled in the retreat mode in which the performance of the engine 2 is set to a special state when the abnormality is abnormal, so that the abnormality is reliably detected. It is necessary.

An example of the drive control for the throttle valve 14 described above is shown in the timing charts of FIGS. FIG. 10A shows that the step position is driven to the fully open step position by the throttle valve fully open confirmation processing (FIG. 9) after the fully open confirmation execution flag Xta is turned “ON” at the time t1, and the fully open state is calculated. This indicates that the fully open switch 22 has been turned “ON” at the step position (time t2). Therefore, "normal" at time t2
Then, the throttle valve is returned to the normal step position by the throttle valve opening control process (FIG. 5) (time t3). In this case, during the current engine operation period, the forced full opening process of the throttle valve 14 by the throttle valve full opening confirmation process (FIG. 9) is not performed again.

FIG. 10 (B) shows that the step position is driven to the fully open step position after the full open confirmation execution flag Xta is turned "ON" at time t11, and the step position is moved ahead of the calculated full open step position (at time t11). At t12), the fully open switch 22 is turned “ON”. In other words, this indicates that the calculated step position has already deviated to a larger value than the actual throttle opening due to a step-out or the like. Therefore, in the initialization processing of step S350, it is initialized to an accurate full-open step position.
Further, at time t12, it is determined that the state is “normal”, and thereafter, the operation is returned to the normal step position (time t13). In this case, during the current engine operation period, the forced full opening process of the throttle valve 14 by the throttle valve full opening confirmation process (FIG. 9) is not performed again.

FIG. 11A shows that the step position is driven to the full open step position after the full open confirmation execution flag Xta is turned "ON" at time t21, and after the calculated full open step position has elapsed. (Time t22) indicates that the full-open switch 22 is turned “ON”. In other words, this indicates that the calculated step position has already shifted to a smaller value with respect to the actual throttle opening due to a step-out or the like. Therefore, step S350
Is initialized to the correct fully open step position. Further, at time t22, a determination of “normal” is made,
Thereafter, the position is returned to the normal step position (time t2
3). In this case, during the current engine operation, the forced full opening of the throttle valve 14 by the throttle valve full opening confirmation processing (FIG. 9) is not performed again.

FIG. 11B shows that the step position is driven to the fully open step position after the full open confirmation execution flag Xta is set to "ON" at time t31. t32), a state in which the fully open switch 22 is not turned “ON”. Therefore, at time t32, it is determined to be "abnormal", and thereafter, the calculation is returned to the normal step position (time t3
3). In this case, during the current engine operation period, the throttle valve 14 is fully forcibly opened again by the throttle valve fully open confirmation process (FIG. 9).
At this time, regardless of whether it is an abnormality determination or a normal determination, the last full-open process in the current operation period is performed.

In the configuration of the first embodiment described above, the full open switch 22 corresponds to the limit opening detecting means. Also, the throttle valve opening control process (FIG. 5) corresponds to the process as the throttle valve control means, the step S225 corresponds to the process as the flow rate saturated opening area calculating means, and the step S230.
Steps S330, S340, and S36 include steps S270, S310, and S320 as processes for achieving the limit opening degree.
0 and S390 correspond to the processing as abnormality determination means.

According to the first embodiment described above, the following effects can be obtained. (I). The throttle opening θstep is a flow saturation opening region θsa obtained from the flow saturation opening region map (FIG. 7).
If it is within t, the throttle valve fully open confirmation processing (FIG. 9) is executed. That is, the condition for forcibly driving the opening of the throttle valve 14 to the limit opening (here, full opening) is not based on a specific opening very close to full opening, but is obtained according to the operating state of the engine 2. By making a determination using the flow rate saturation opening area θsat, the throttle valve fully open confirmation processing (FIG. 9) is executed.

Therefore, in a wider operation range than before,
The step motor 18 can be driven such that the throttle opening is fully opened without affecting the operation state of the engine 2 such as emission. By doing so, the operation region in which the throttle valve fully open confirmation process (FIG. 9) is executed is widened, and it is possible to prevent the throttle valve fully open confirmation process (FIG. 9) from being unable to be executed for a long time. Therefore, the step motor 18 can be driven at an appropriate frequency so that the throttle opening is fully opened, and abnormality detection and initialization can be performed.

(B). Further, the conditions for executing the throttle valve fully open confirmation processing (FIG. 9) include that the fluctuation amount ΔQ of the fuel injection amount Q and the rotation speed fluctuation amount ΔNE of the engine 2 are within the stable ranges. As a result, the step motor 18 can be driven so that the throttle opening is fully opened when the full-open confirmation execution condition is stably satisfied. Therefore, the possibility that the flow rate saturation opening area is reduced while the throttle opening is fully opened is reduced, and the adverse effect on the engine operation can be effectively prevented.

(C). Further, the throttle valve fully open confirmation process (FIG. 9) is not executed unless the condition for executing the full open confirmation has been satisfied for the time reference value C or more. As a result, the step motor 18 can be driven such that the throttle opening reaches the limit opening when the full-open confirmation execution condition is stably satisfied. Therefore, the possibility that the flow rate saturation opening region is reduced while the throttle opening is set to the limit opening is reduced, and an adverse effect on the engine operation can be effectively prevented.

(D). Also, the execution of the throttle valve fully open confirmation process (FIG. 9) is performed in one operation period (period from start to stop of the engine 2). It is prohibited after detecting twice. Thus, the opening of the throttle valve 14 does not change to the limit opening more frequently than necessary. Therefore, the durability of the full-open switch 22 can be improved without the full-open switch 22 being repeatedly turned on and off more frequently than necessary.

Also, in this case, in one operation period, the judgment of normal is performed only once, but the judgment of abnormal is performed twice. Get higher.

[Embodiment 2] In the present embodiment, FIG.
2 and the confirmation end flag OFF setting process of FIG. 13 are executed in place of the fully open confirmation process start determination process shown in FIG. 6 of the first embodiment, and the throttle valve fully open confirmation process of FIG. The difference is that the process is executed instead of the throttle valve fully open confirmation process of FIG. 9 of the first embodiment. The other configuration is the same as that of the first embodiment.

The full-open confirmation processing start determination processing (FIG. 12) will be described. This process is a process that is repeatedly executed in a time cycle. When the process is started, it is first determined whether or not the full-open confirmation execution flag Xta is “OFF” (S121).
0). If the full-open confirmation execution flag Xta is “ON” (“NO” in S1210), since the later-described throttle valve full-open confirmation processing has been executed, this processing is once ended as it is. Note that Xta = “OFF” is initially set by the initial setting when the power of the ECU 20 is turned on.

If Xta = “OFF” (S1210
Then, based on the operating state of the engine 2, here, the fuel injection amount Q and the engine speed NE from the flow rate saturation opening area map shown in FIG. 7 described in the first embodiment. The flow rate saturation limit step position θL is obtained, and a flow rate saturation opening degree region (flow rate saturation limit step position θL to fully open step position) is set (S1220).

Next, it is determined whether or not the condition for executing the full-open confirmation is satisfied (S1230). Here, the full open confirmation execution conditions are the same three conditions as described in the first embodiment. That is, “(1) throttle opening θste
p is within the flow rate saturation opening region θsat, (2) the fuel injection amount Q
Is the reference value Qa or less, and (3) the variation ΔNE of the engine speed NE is the reference value NEa or less. "

If at least one of the above (1) to (3) is not satisfied, it is determined that the fully open confirmation execution condition is not satisfied (“NO” in S1230), and then the unsatisfied history flag Xout is set to “NO”. "ON" is set (S1240), and this process is once ended. Note that the failure history flag Xout is E
It is initially set to “ON” when the power of the CU 20 is turned on.

If all of the above conditions (1) to (3) are satisfied, it is determined that the full open confirmation execution condition has been satisfied ("YES" in S1230), and then the confirmation end flag Xe
It is determined whether nd is “OFF” (S1250).
The confirmation end flag Xend is initially set to “OFF” when the power of the ECU 20 is turned on.

If Xend = “ON” (S1250)
, "NO"), and the process is once ended. Xend = "O
If it is “FF” (“YES” in S1250), “ON” is set to the full-open confirmation execution flag Xta (S1260),
"ON" is set to the confirmation end flag Xend (S127).
0), “OFF” is set to the unsatisfied history flag Xout (S1280), and the present process is ended once.

Next, a confirmation end flag OFF setting process (FIG. 1)
3) will be described. This process is a process that is repeatedly executed in a time cycle. When the process is started, first, it is determined whether or not the state where the confirmation end flag Xend is “ON” has continued for 30 seconds or more (S1310). Xend =
If the time is less than 30 seconds even if “OFF” or Xend = “ON” (“NO” in S1310), the present process is terminated as it is.

On the other hand, if Xend = “ON” continues for 30 seconds or more (“YES” in S1310), it is next determined whether or not the failure history flag Xout is “ON” (S13).
1320). If Xout = “OFF” (S132)
0 and “NO”), the process is once ended. Xout =
If it is “ON” (“YES” in S1320), “OFF” is set in the confirmation end flag Xend (S133).
0), this process is temporarily ended.

The above-described fully open confirmation process start determination process (FIG. 1)
By the process of 2) and the process of setting the confirmation end flag OFF (FIG. 13), the frequency at which the fully open confirmation execution flag Xta is turned “ON” is adjusted so as not to be high. Then, a throttle valve fully open confirmation process shown in FIG. 15 is executed according to the contents of the full open confirmation execution flag Xta. The processing in FIG. 15 is the same as the processing shown in FIG. 9 of the first embodiment except that the increment processing of the counters Cnr and Cab (steps S370 and S400) does not exist. That is, steps S1410 to S1490 in FIG. 15 and step S14 in FIG.
Steps 310 to S360, S380, and S390 are the same processing.

FIG. 14 is a timing chart showing an example of an operation performed by the full open confirmation processing start determination processing (FIG. 12) and the confirmation end flag OFF setting processing (FIG. 13) to set Xta = “ON” to an appropriate frequency. . That is, initially, X
ta = “OFF” (“YES” in S1210), and the fully open confirmation execution condition is not satisfied (“N” in S1230)
O ”), Xout =“ ON ”(S1240), Xend
= "OFF". At time t50, the fully open confirmation execution condition is satisfied (“YES” in S1230).
Since Xend = “OFF” at this time (S12
50, “YES”), Xta = “ON” (S126)
0), Xend = "ON" (S1270) and Xou
t = “OFF” (S1280). Xta = “O
N ", the throttle valve fully open confirmation process (FIG. 15) is determined to be" YES "in step S1410, and the process of fully opening the throttle valve 14 (S1).
420) is executed, and steps S1430 to S146 are executed.
At 0, S1490, initialization and determination of normal or abnormal are made. When the determination is completed, Xta is returned to "OFF" (S1480).

Thereafter, the condition for executing the full-open confirmation is satisfied (S123).
Even if “YES” continues at 0, Xend = “ON” (“NO” at S1250), so Xta = “ON”
Does not. In the confirmation end flag OFF setting process (FIG. 13), even if Xend = “ON” continues for 30 seconds or more (“YES” in S1310), at least Xout
= "OFF"("NO" in S1320). For this reason, Xend = “OFF” does not occur, so that Xta =
“OFF” is maintained, and in the throttle valve fully open confirmation processing (FIG. 15), “NO” is determined in the step S1410, and the throttle valve 14 is fully opened (S142).
0) is never executed. Such a state in which the full opening process of the throttle valve 14 is prohibited is performed as long as the condition for executing the full opening check is satisfied.

Next, the continuation of satisfaction of the full-open check execution condition is 30
After the second (time t51), if the fully open confirmation execution condition is not satisfied (time t52: “NO” in S1230),
Xout = “ON” (S1240). Accordingly, in the confirmation end flag OFF setting process (FIG. 13), “YES” is determined in the step S1320, and Xend
= “OFF” (S1330). However, at this point, the fully open confirmation execution condition is not satisfied (“N” in S1230).
O ”), Xta =“ OFF ”is maintained, and the throttle valve 14 is not fully opened (S1420).

Then, when the full-open confirmation execution condition is satisfied (time t53: “YES” in S1230), Xend has already been returned to “OFF” (S1250).
"YES"), Xta = "ON" (S1260), X
end = “ON” (S1270) and Xout = “O
FF "(S1280). Since Xta = “ON”, the process of fully opening the throttle valve 14 (S
1420) is executed, and steps S1430 to S14 are executed.
In step S1490, initialization and determination of normal or abnormal are made, and Xta is returned to "OFF" (S1480).

Next, if the condition for executing the full-open check is temporarily unsatisfied (time t54 to t55) within 30 seconds from the time t53 when the process of fully opening the throttle valve 14 is executed, the condition for executing the fully-open check is not satisfied. At the timing (time t54: “NO” in S1230), Xout =
It becomes "ON" (S1240). Then, the fully open confirmation execution condition is satisfied at time t55 (“YE in S1230”).
S "). However, the confirmation end flag OFF setting process (FIG. 1)
In 3), since the state of Xend = “ON” is less than 30 seconds (“NO” in S1310), Xend = “OFF” is not returned. Therefore, even if the full-open confirmation execution condition is satisfied (“YES” in S1230), Xend = “O”
N ”(“ NO ”in S1250), Xt
a = “OFF” is maintained and the throttle valve 14 is not fully opened (S1420).

When the state of Xend = “ON” is 30
After the lapse of seconds (time t56: “YE
S "), since Xout =" ON "already (S132)
0 and “YES”), Xend = “OFF” (S1)
330). For this reason, the full open confirmation process start determination process (FIG. 1)
2) In steps S1230 and S1250, "YE
S ”, Xta =“ ON ”(S1260),
Xend = “ON” (S1270) and Xout =
"OFF" (S1280), the throttle valve 1
4 is performed (S1420).

As shown from time t56 to time t57, as long as Xend = “ON” does not exceed 30 seconds, the throttle opening throttle execution condition is repeatedly established and satisfied regardless of how many times during this period. The valve 14 is fully opened (S1
420) is not performed. Xend = “ON”
If the condition for performing the full-open check is satisfied after the state of (3) has elapsed for 30 seconds (time t57), the fully-open process of the throttle valve 14 (S1420) is executed. Also, Xend
= After 30 seconds of the “ON” state, if the fully open confirmation execution condition is not satisfied (time t58), then
Timing when full open confirmation execution condition is satisfied (time t59)
, The throttle valve 14 is fully opened (S1420). Also, as mentioned earlier, Xend =
After 30 seconds of the “ON” state, even if the full-open confirmation execution condition is satisfied (time t60), Xend = “O”
If the full-open confirmation execution condition has never been satisfied during "N", the full-open process of the throttle valve 14 is not executed at that time (time t60). Thereafter, at the timing (time t61) when the full-open confirmation execution condition is not satisfied once and is satisfied again (time t61), the full-open process of the throttle valve 14 (S1420) is executed.

In the configuration of the second embodiment described above, step S1220 is replaced by steps S1230, S1260, and S141 in the processing as flow rate saturation opening area calculation means.
0 and S1420 correspond to the processing as the limit opening realizing means, steps S1430 to S1460 and S1490 correspond to the processing as the abnormality determining means, and steps S1240 and S125.
0, S1270, S1280, S1310 to S1330
Corresponds to the processing as the limit opening realization prohibition means.

According to the second embodiment described above, the following effects can be obtained. (I). The effects (a) and (b) of the first embodiment are obtained. (B). Once the throttle valve 14 is fully opened, the throttle valve 14 is completely opened until a reference time (30 seconds in this case) elapses. As a result, in the case where the full open confirmation execution condition is satisfied for a long time,
Frequent opening of the throttle valve 14 is prevented from being performed frequently, and abnormality determination and initialization can be performed at an appropriate frequency. Further, the durability of the full-open switch 22 can be improved.

(C). Furthermore, even if the abnormality determination is performed again while the full-open confirmation execution condition is satisfied, it is considered that there is no significant change in the situation, and it is considered that the possibility of an abnormality is small. Therefore, after executing the full opening process of the throttle valve 14, the execution of the full opening process of the throttle valve 14 is prohibited at least once until the condition for executing the full opening check is not satisfied and the reference time has elapsed. This can reduce unnecessary processing for fully opening the throttle valve 14, and can further improve the durability of the fully open switch 22.

[Third Embodiment] In the third embodiment, a fully open confirmation process start determination process shown in FIG. 16 is executed instead of the fully open confirmation process start determination process shown in FIG. The other configuration is the same as that of the second embodiment. Steps S1510 and S1 of the fully open confirmation process start determination process (FIG. 16) of the third embodiment.
Steps 550 to S1590 correspond to steps S1210 and S1 of the full-open confirmation processing start determination processing (FIG. 12) of the second embodiment.
The processing is the same as each of steps 240 to S1280. The processing different from the second embodiment is described in steps S1520 to S1.
540. That is, in order to shift to the determination whether or not the confirmation end flag Xend is “OFF” in step S1560, first, it is determined whether or not the fuel injection amount Q is within the reference range Qy to Qx indicating a stable operation state. Is determined. If Qy <Q <Qx (“YE” in S1520)
S "), it is then determined whether or not the engine speed NE is within a reference range NEy to NEx indicating a stable operation state. If NEy <NE <NEx ("YES" in S1530), it is next determined whether or not the throttle opening θstep is smaller than the step position θx near the full opening position (larger as the opening) (S1540). Here, the step position θx near the fully open position is such that the throttle valve 14 is in the fully open state in an operating state in which the above-mentioned conditions of Qy <Q <Qx and NEy <NE <NEx are satisfied with respect to the engine 2. The fixed step position corresponding to the opening indicating substantially the same air flow rate is set. That is, the step position θx indicates a flow saturation opening degree area narrower than the flow saturation limit step position θL calculated from the map of FIG. 7 used in the first and second embodiments.

Steps S1520 to S1540 described above
If at least one of the three conditions is not satisfied (S152
0, “NO” in S1530 or S1540), and “ON” is set in the failure history flag Xout (S155).
0).

If all three conditions of steps S1520 to S1540 are satisfied (S1520, S1
"YES" in steps 530 and S1540), step S1
The confirmation end flag Xend in 560 is “OFF”
The process proceeds to the determination of whether or not (S1560). The subsequent processing is as described with reference to FIG. 12 of the second embodiment.

In the configuration of the third embodiment described above, steps S1520 to S1540, S1570, S141
0, S1420 to the processing as the limit opening realizing means, steps S1430 to S1460, S1490 to the processing as the abnormality determining means, and steps S1550, S156.
0, S1580, S1590, S1310 to S1330
Corresponds to the processing as the limit opening realization prohibition means.

According to the third embodiment described above, the following effects can be obtained. (I). In the third embodiment, unlike the first and second embodiments, the flow saturation limit step position θL is not obtained from the map, but is a step position near the fully open position of the throttle valve 14 and is reliably in the fully open state in the operating region. Is used as a flow-saturation limit step position, which is a fixedly set step position θx that indicates an intake amount substantially the same as the intake amount at the time. Even when the condition for executing the full-open check is maintained for a long time, the throttle valve 1
4 can be prevented from being frequently performed, and abnormality determination and initialization can be performed at an appropriate frequency. Thus, the durability of the fully open switch 22 can be improved.

(B). The condition that the throttle opening is fully opened from the step position θx in an operating state in which the load and the number of revolutions of the engine 2 are within the reference range is defined as a fully open confirmation execution condition. As a result, the step motor 18 can be driven so that the throttle opening is fully opened when the full-open confirmation execution condition is stably satisfied. Therefore, the possibility that the flow rate saturation opening region is reduced while the throttle opening is fully opened is reduced, and adverse effects on the engine operation can be prevented.

(C). The effects (b) and (c) of the second embodiment are obtained. [Other embodiments]-In the first embodiment,
The flow rate saturation opening area map (FIG. 7) for calculating the flow rate saturation limit step position θL is a two-dimensional map using the fuel injection amount Q and the engine speed NE as parameters. A one-dimensional map using only several NEs as parameters may be used. Alternatively, a one-dimensional map may be used in which the amount of intake air obtained by providing an air flow meter in the intake passage 4 is used as a parameter.

In the second and third embodiments, the condition is that the condition for executing the full-open check is not satisfied at least once.
Although the throttle valve 14 is fully opened after a time of 0 seconds, the throttle valve 14 can be fully opened by setting a time interval of 30 seconds or the like without the condition that the execution condition of the full opening check is not satisfied. The execution frequency of the process may be set to an appropriate value.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a diesel engine and a control system thereof according to a first embodiment.

FIG. 2 is a sectional view showing a configuration of a throttle valve and a drive mechanism thereof according to the first embodiment.

FIG. 3 is a front configuration diagram of the throttle valve and a driving mechanism thereof.

FIG. 4 is a partial cross-sectional view of a drive mechanism of the throttle valve.

FIG. 5 is a flowchart of a throttle valve opening control process executed by the ECU according to the first embodiment;

FIG. 6 is a flowchart of a fully open confirmation process start determination process executed by the ECU.

FIG. 7 is a configuration explanatory diagram of a flow rate saturation opening area map used in the full opening confirmation processing start determination processing.

FIG. 8 is an explanatory diagram showing an example of a change in the value of the flow rate saturation opening area map.

FIG. 9 is a flowchart of a throttle valve fully open confirmation process executed by the ECU.

FIG. 10 is a timing chart showing an example of control by processing of the ECU.

FIG. 11 is a timing chart showing an example of control by the processing of the ECU.

FIG. 12 is a flowchart of a fully open confirmation process start determination process executed by an ECU in the second embodiment.

FIG. 13 is a flowchart of a confirmation end flag OFF setting process executed by an ECU in the second embodiment.

FIG. 14 is a timing chart showing an example of control by processing performed by an ECU according to the second embodiment.

FIG. 15 is a flowchart of a throttle valve fully open confirmation process executed by the ECU in the second embodiment.

FIG. 16 is a flowchart of a fully open confirmation process start determination process executed by the ECU according to the third embodiment.

[Explanation of symbols]

2 ... Engine, 2a ... Output shaft, 2b ... Cylinder block, 3 ... Combustion chamber, 3a ... Sub-combustion chamber, 4 ... Intake passage, 6 ...
Air cleaner, 8: pressure sensor, 10: intake air temperature sensor,
14: throttle valve, 14a: valve shaft, 14b: throttle body, 14c: return spring, 14d,
14e: arm portion, 14f: lever, 14g: relief spring, 16: drive mechanism, 16a: driven gear, 16
b: gear box, 16c: support shaft, 16d: second intermediate gear, 16e: first intermediate gear, 16f: groove portion, 18: step motor, 18a: output shaft, 18b: drive gear, 20
... ECU, 22 ... Fully open switch, 24 ... Exhaust passage, 26
... EGR passage, 28 ... actuator, 30 ... EGR control valve, 32 ... fuel injection nozzle, 34 ... fuel injection pump, 34a ... timer control valve, 34b ... spill valve, 36 ... speed sensor, 38 ... accelerator opening sensor, 40 ... IG switch, 42 ... Starter switch, 44 ... Cooling water temperature sensor, 46 ... Pressing part.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F02D 43/00 301 F02D 43/00 301K 45/00 345 45/00 345Z 362 362J 364 364G F-term (reference) 3G065 AA01 CA34 CA36 CA38 DA06 DA15 EA07 EA10 FA12 GA00 GA09 GA10 GA18 GA26 GA27 GA41 GA46 HA20 HA21 HA22 JA04 JA09 JA11 KA02 KA15 KA16 KA17 3G084 AA01 BA05 BA13 BA15 BA19 BA20 DA19 DA26 DA27 DA33 EA07 EA11 FA03 EA07 EA07 FA03 HA13 JB02 JB07 JB09 LA03 LC04 MA11 MA18 NA08 NB11 NC02 NC08 NE23 PA09Z PA10Z PA11Z PA13Z PA17Z PA19Z PE01Z PE02Z PE08Z PF03Z PF16Z

Claims (15)

[Claims] 1. A step motor for adjusting a throttle opening by driving a throttle valve of an internal combustion engine, and a throttle valve for driving the step motor to set the throttle valve to a throttle opening corresponding to an operation state of the internal combustion engine. An abnormal time processing device for a step motor driven throttle valve provided with a control means, a limit opening detection means for detecting that the throttle valve has reached a limit opening, and an air flow rate at the limit opening. A flow-saturation-opening region calculating means for obtaining a flow-saturation-opening region indicating substantially the same air flow rate according to the operating state of the internal combustion engine; Assuming that the throttle opening has entered into the limit opening realization condition, and the limit opening realization condition is satisfied,
A limit opening realizing unit that drives the step motor so that the throttle opening becomes the limit opening; and the step motor is driven by the limit opening realizing unit so that the throttle opening becomes the limit opening. An abnormality determining means for determining an abnormality in accordance with a detection content of the limit opening degree detecting means in the above case, a step motor driven throttle valve abnormality processing apparatus. 2. The configuration according to claim 1, wherein the limit opening realizing means calculates that the load fluctuation and the rotation speed fluctuation of the internal combustion engine are within a stable range and the flow rate saturated opening area calculating means calculates the limit opening degree. When the throttle opening is within the flow rate saturated opening region, the stepping motor is controlled so that the throttle opening becomes the limit opening when the limit opening realizing condition is satisfied. And a step motor driving type throttle valve abnormality processing apparatus. 3. The configuration according to claim 1, wherein the limit opening realizing means is based on a state in which the throttle opening is within the flow rate saturated opening area calculated by the flow rate saturated opening area calculating means. As a condition for realizing the limit opening,
An abnormality processing device for a step motor driven throttle valve, wherein the step motor is driven such that the throttle opening becomes the limit opening when the limit opening realizing condition is satisfied. 4. The configuration according to claim 1, wherein the limit opening degree realizing means calculates that the load fluctuation and the rotation speed fluctuation of the internal combustion engine are within a stable range, and the flow rate saturation opening area calculating means calculates the limit fluctuation. Assuming that the state in which the throttle opening is within the flow rate saturated opening area has continued for the reference time is the limit opening realization condition, and when the limit opening realization condition is satisfied, the throttle opening becomes the limit opening. A step motor driving type throttle valve abnormality processing apparatus, wherein the step motor is driven so that 5. The processing of the limit opening degree realizing means when the abnormality determining means makes a reference number of times during one internal combustion engine operation period with respect to the configuration according to claim 1. A step motor drive type throttle valve abnormality processing device, comprising a limit opening realization prohibiting means for prohibiting the opening of the throttle valve. 6. The configuration according to claim 1, wherein the abnormality determination means determines whether an abnormality has been made a reference number of times during one operation period of the internal combustion engine and whether the abnormality is not an abnormality. A step-motor-driven throttle valve characterized by comprising a limit opening realization prohibiting means for prohibiting the processing of the limit opening realizing means when either of the reference times is satisfied and Processing equipment. 7. The processing according to any one of claims 1 to 4, wherein the processing of said limit opening realizing means is inhibited until the reference time elapses after the processing of said limit opening realizing means is performed. An abnormal time processing device for a step motor driven throttle valve, comprising a limit opening realization prohibiting means for performing the operation. 8. The configuration according to claim 1, wherein the limit opening realizing condition is not satisfied at least once after the processing of the limit opening realizing means is performed, and the reference time elapses. A step motor drive type throttle valve abnormality processing device, further comprising a limit opening realization prohibiting unit for prohibiting the processing of the limit opening realizing unit until the processing is performed. 9. A step motor for adjusting a throttle opening by driving a throttle valve of an internal combustion engine, and a throttle valve for driving the step motor to set the throttle valve to a throttle opening corresponding to an operation state of the internal combustion engine. An abnormal time processing device for a step motor driven throttle valve, comprising: control means; a limit opening detection means for detecting that the throttle valve has reached a limit opening; The opening degree of the throttle motor is controlled such that the throttle opening is equal to the limiting opening when the limiting opening realizing condition is satisfied. And when the step motor is driven such that the throttle opening is the limit opening by the limit opening realizing means, After the processing of the limit opening realizing means is performed, the processing of the limit opening realizing means is inhibited until a reference time has elapsed after the processing of the limit opening realizing means is performed. And a limit opening realization prohibiting means that performs the following processing. 10. The configuration according to claim 9, wherein said limit opening degree realizing means determines that the load and the rotation speed of the internal combustion engine are within a reference range and that the throttle opening degree is close to the limit opening degree. And a step motor driving throttle wherein the step motor is driven such that the throttle opening becomes the limit opening when the limit opening realizing condition is satisfied. Valve abnormality handling device. 11. The configuration according to claim 9, wherein said limit opening realization prohibiting means becomes unsatisfied at least once after the processing of said limit opening realizing means is performed. And until the reference time has passed,
An abnormality processing apparatus for a step motor driven throttle valve, wherein the processing by the limit opening realizing means is prohibited. 12. The configuration according to claim 1, wherein said abnormality determining means drives said stepping motor such that said throttle opening is at a limit opening by said limit opening realizing means. An abnormality processing device for a step motor driven throttle valve, characterized in that it is determined that an abnormality has occurred unless the limit opening degree detection means detects that the throttle valve has reached the limit opening degree. 13. The configuration according to claim 1, wherein said stepping motor is driven by said limit opening realizing means so that the throttle opening becomes the limit opening instead of said abnormality judging means. In this case, when the limit opening detecting means detects that the throttle valve has reached the limit opening, there is provided initialization means for initializing the throttle opening as a throttle opening corresponding to the limit opening. An abnormal condition processing device for a step motor driven throttle valve, characterized in that: 14. The apparatus according to claim 1, wherein said step opening motor is driven by said limit opening realizing means so that the throttle opening becomes the limit opening. A step of initializing the throttle opening as a throttle opening corresponding to the limit opening when the opening detection means detects that the throttle valve has reached the limit opening. Abnormal processing unit for motor-driven throttle valve. 15. The abnormality of a step motor driven throttle valve according to claim 1, wherein said internal combustion engine is a diesel engine, and said limit opening is in a fully open state. Time processing device.