JPH10220271A - Controller of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller capable of accurately judging one abnormality of a sub passage without being affected by the other sub passage, in an internal combustion engine in which two sub passages for bypassing an opening and closing means provided on the way of a main passage are provided. SOLUTION: First and second control valves for opening and closing an assist air passage and an auxiliary air passage are closed in the deceleration fuel cut state where a throttle valve of an intake passage is approximately full closed, and intake pipe inside absolute pressure PBA obtained when the executing condition of abnormality judgement is held is stored (S34) as initial pressure PBAAIB. Next, only the first control valve is opened (S39), and it is judged (S41, S42, S44) that the assist air passage is abnormal when the change amount DPBAAI of intake pipe inside absolute pressure PBA after the specified time TFSAA passes is smaller than the specified change amount DPBFSAA.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine, and more particularly to a control device having a function of determining an abnormality in a passage such as air provided in the internal combustion engine.

[0002]

2. Description of the Related Art In an internal combustion engine in which a fuel injection valve is provided in the middle of an intake passage, a sub-intake passage opening near the fuel injection valve is provided in order to promote atomization of fuel. A device for supplying auxiliary air (hereinafter referred to as "assist air") is conventionally known. Further, a method of determining an abnormality such as clogging or perforation of the auxiliary intake passage (hereinafter, referred to as "assist air passage") is disclosed in Japanese Patent Application Laid-Open No. Hei 3-217639.

According to the technique described in this publication, the opening / closing means for opening / closing the auxiliary intake passage is forcibly switched from the open state to the closed state or vice versa in the specific operating state of the engine, and the engine operation at the time of the switching is performed. An abnormality in the sub intake passage is determined based on the detected value of the parameter.

More specifically, when the normal opening / closing means is in the closed state after the engine has been warmed up, the opening / closing means is forcibly opened, and if the maximum value of the engine speed is equal to or less than a predetermined value, an abnormality is detected. (First method), the opening / closing means is always opened during the warm-up operation, and is closed for a predetermined time only when the abnormality is detected, and the abnormality is determined based on the change amount of the engine speed at that time. A determination method (second method) and the like are shown.

[0005]

However, in the above-described conventional determination method, an engine provided with an auxiliary air passage for controlling the engine speed during idling or deceleration of the engine is provided separately from the assist air passage. In the above, when the opening / closing means of the assist air passage is forcibly opened / closed, if there is a change in the flow rate of the air supplied through the auxiliary air passage, the abnormality determination cannot be performed accurately. There is.

In the first method, since the assist air is temporarily supplied in a state where the assist air is originally unnecessary, the amount of the assist air must be reduced, and it is difficult to make an accurate determination. is there. Further, in the second method,
Since the supply of the assist air is temporarily interrupted during the warm-up operation, the atomization of the fuel may be insufficient.

It is also desired to simplify not only the assist air passage but also the auxiliary air passages and the opening / closing means for opening and closing them, and to reduce the number of parts.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and in an internal combustion engine provided with two sub-passages which bypass opening / closing means provided in the middle of a main passage, one abnormality of the sub-passage is provided. It is an object of the present invention to provide a control device that can accurately judge the above without being affected by other sub-passages.

[0009]

According to a first aspect of the present invention, there is provided a main passage having a first opening / closing means, a first sub-passage bypassing the first opening / closing means, and a first passage. In a control device for an internal combustion engine including two sub-passages and second and third opening / closing means provided in the first sub-passage and the second sub-passage, the first opening / closing means is substantially in a closed state. And detecting means for detecting that the first opening / closing means is substantially in the closed state, while maintaining the third opening / closing means in the closed state,
Switching means for forcibly switching the second opening / closing means from the closed state to the open state or vice versa; and when the amount of change in the flow rate of the first sub-passage at the time of operation of the switching means is equal to or less than a predetermined amount of change, Determining means for determining that the first sub-passage is abnormal.

Here, the "predetermined change amount" is a value between the flow change amount when the first sub-passage is normal and the flow change amount when the first sub-passage is abnormal, for example, it cannot be normal. The flow rate is set to a small amount.

According to this structure, while the third opening / closing means is maintained in the closed state when the first opening / closing means is substantially closed, the second opening / closing means is forcibly moved from the closed state. It is switched to the open state or vice versa, and when the amount of change in the flow rate of the first sub passage at the time of the switch is equal to or less than a predetermined change amount, it is determined that the first sub passage is abnormal.

According to a second aspect of the present invention, there is provided an intake passage provided with a throttle valve, an assist air passage which bypasses the throttle valve and opens near a fuel injection valve of the engine, and a bypass which bypasses the throttle valve. A control device for an internal combustion engine, comprising: an auxiliary air passage provided for controlling the engine speed; and a first control valve and a second control valve provided in the assist air passage and the auxiliary air passage, respectively. A detecting means for detecting a fuel supply cutoff state at the time of engine deceleration; and a second control valve when the fuel supply cutoff state at the time of engine deceleration is detected by the detecting means. While keeping the closed
Switching means for forcibly switching the first control valve from the closed state to the open state or vice versa; and when the change amount of the flow rate of the assist air passage at the time of operation of the switch means is equal to or less than a predetermined change amount, Determining means for determining that the air passage is abnormal;

According to this configuration, when it is detected that the fuel supply is cut off when the engine is decelerated, the first control valve is forcibly moved while the second control valve is kept closed. The state is switched from the closed state to the open state or vice versa, and when the amount of change in the flow rate of the assist air passage at the time of the switch is equal to or less than a predetermined amount of change, it is determined that the assist air passage is abnormal.

According to a third aspect of the present invention, in the control apparatus for an internal combustion engine according to the first aspect, the second and third opening / closing means are integrated control valves, and the second and third opening / closing means are integrated. The opening / closing control of the third opening / closing means can be executed by one driving signal.

According to this configuration, the flow rate of the first and second sub passages is controlled by the control valve in which the second and third opening / closing means are integrated, and the opening and closing of the second and third opening / closing means are performed. Control is performed by one drive signal.

The invention described in claim 4 is the first or third invention.
3. The control device for an internal combustion engine according to claim 1, wherein a maximum flow rate of the first sub-passage among the main passage, the first and second sub-passages is the smallest.

According to this configuration, the main passage, the first and the second passages are provided.
An abnormality in the first sub passage having the smallest maximum flow rate among the sub passages is determined.

According to a fifth aspect of the present invention, in the control device for an internal combustion engine according to the third aspect, the integrated control valve is such that the second and third opening / closing means are both closed. (1) an operating area, a second operating area in which only the second opening / closing means can be opened, and a third operating area in which both the second and third opening / closing means can be opened. Features.

According to this configuration, the abnormality can be determined by using the second operating region in which only the second opening / closing means can be opened.

[0020]

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

FIG. 1 is an overall configuration diagram of an internal combustion engine (hereinafter referred to as "engine") and a control device thereof according to an embodiment of the present invention. For example, a throttle is provided in the middle of an intake pipe 2 of a four-cylinder engine 1. A valve 3 is provided. A throttle valve opening (θTH) sensor 4 is connected to the throttle valve 3, and outputs an electric signal corresponding to the opening of the throttle valve 3 to output an electronic control unit for engine control (hereinafter referred to as “ECU”) 5. To supply.

A fuel injection valve 6 is provided for each cylinder between the engine 1 and the throttle valve 3 and slightly upstream of an intake valve (not shown) in the intake passage 2. Each injection valve is connected to a fuel pump (not shown). The ECU 5 is electrically connected to the ECU 5 and controls a valve opening time of fuel injection based on a signal from the ECU 5.

A branch passage 13 is provided upstream of the throttle valve 3 in the intake passage 2, and an electromagnetic control valve 15 is mounted at an end of the branch passage 13. The branch passage 13 is
The electromagnetic control valve 15 is configured to be branched into an auxiliary air passage 14 opening downstream of the throttle valve 3 and an assist air passage 16 opening near the injection port of the fuel injection valve 6 (see FIG. 2 described later). reference). That is, when the intake passage 2 is the main passage, the auxiliary air passage 14 and the assist air passage 16 constitute a sub-passage that bypasses the throttle valve 3. The assist air passage 16 is actually provided so as to be branched and open in the vicinity of each injection port of a fuel injection valve provided for each cylinder. The flow path cross-sectional area (maximum flow rate) of the intake passage 2, the auxiliary air passage 14, and the assist air passage 16 is configured such that the intake passage 2 is the largest and the auxiliary air passage 14 and the assist air passage 16 become smaller in this order. I have. The intake passage 2, the assist air passage 16, and the auxiliary air passage 14 correspond to the main passage, the first sub passage, and the second sub passage, respectively, as described in the claims.

On the other hand, an intake pipe absolute pressure (PBA) sensor 7 is provided immediately downstream of the throttle valve 3. The absolute pressure signal converted into an electric signal by the absolute pressure sensor 7 is supplied to the ECU 5. . Further, an intake air temperature (TA) sensor 8 is mounted downstream thereof, detects the intake air temperature TA, outputs a corresponding electric signal, and supplies the electric signal to the ECU 5.

The engine water temperature (TW) sensor 9 mounted on the main body of the engine 1 is composed of a thermistor or the like, detects the engine water temperature (cooling water temperature) TW, outputs a corresponding temperature signal, and supplies it to the ECU 5. The engine speed (NE) sensor 10 and the cylinder discrimination (CYL) sensor 11 are mounted around a camshaft or a crankshaft (not shown) of the engine 1. The engine speed sensor 10 outputs a pulse (hereinafter, referred to as a “TDC signal pulse”) at a predetermined crank angle position every time the crankshaft of the engine 1 rotates 180 degrees, and the cylinder discrimination sensor 11 outputs a predetermined crank angle position of a specific cylinder. And outputs a signal pulse. These signal pulses are supplied to the ECU 5.

The ECU 5 further includes a vehicle speed sensor 22 for detecting a speed VH of a vehicle on which the engine 1 is mounted, a voltage sensor 23 for detecting an output voltage VAGC of a generator driven by the engine 1, and an on / off switch for an air conditioner. Various switches 24 such as a power steering ON / OFF switch and a shift switch indicating whether or not the automatic transmission is in a neutral state are connected. The detection signals of these sensors and the switching signals of the switches are supplied to the ECU 5.

The ECU 5 has functions such as shaping input signal waveforms from various sensors, correcting a voltage level to a predetermined level, and converting an analog signal value to a digital signal value, and a central processing circuit (hereinafter referred to as a central processing circuit). A storage means for storing various calculation programs executed by the CPU and calculation results, an output circuit for supplying drive signals to the fuel injection valve 6, the electromagnetic control valve 15, and the like. The ECU 5 constitutes a part of the detecting means, the switching means, and the determining means described in the claims.

The CPU determines various engine operating conditions based on the various engine parameter signals described above, and controls the drive of the electromagnetic control valve 15, the fuel injection valve 6, and the like according to the determined engine operating conditions. Is performed, and an abnormality caused by clogging of the assist air passage 16 is determined.

FIG. 2 is a diagram for explaining the configuration and operation of the electromagnetic control valve 15. First, the configuration will be described with reference to FIG. The electromagnetic control valve 15 is provided in the valve chamber 52 and fixed to the valve shaft 63 by the first and second valve bodies 6.
The valve member 60 includes a valve member 60 composed of a valve member 62 and a drive coil 51 that drives the valve member 60 by applying an electromagnetic force to the valve shaft 63. The valve bodies 61 and 62 are provided with passages 61a and 62a, respectively, so that the branch passage 13 and the assist air passage 16 can communicate with each other via the valve chamber 52.
The first valve body 61 controls opening and closing of the opening of the assist air passage 16, and the second valve body controls opening and closing of the opening of the auxiliary air passage 14. Hereinafter, a valve constituted by the first valve body 61 and the opening of the assist air passage 16 is referred to as a first control valve 71, and the second valve body 62 and the auxiliary air passage 14
The second control valve 72 is a valve constituted by the above-mentioned opening. The first and second control valves 71 and 72 correspond to the second and third opening / closing means described in the claims, respectively.

The width of the first and second valve bodies 61 and 62 in the vertical direction (the direction in which the valve bodies 61 and 62 move) is the width of the opening of the assist air passage 16 and the auxiliary air passage 14 in the vertical direction, respectively. More widely configured and the first and second
The mounting intervals of the valve bodies 61 and 62 are set so that the flow control described below can be realized in accordance with the positional relationship between the opening of the assist air passage 16 and the opening of the auxiliary air passage 14. .

Next, the operation of the electromagnetic control valve 15 will be described with reference to FIGS. FIG. 3 shows the relationship between the lift amount LFT and the maximum flow rate QMAX of the auxiliary air passage 14 and the assist air passage 16 when the displacement in the direction of the arrow shown in FIG. 2A is defined as the lift amount LFT of the valve member 60. FIG. 4 is a diagram showing a relationship, in which lines L1 and L2 correspond to the assist air passage 16 and the auxiliary air passage 14, respectively. 2A to 2E correspond to the lift amounts LFT1 to LFT5 in FIG. 3, respectively. That is, FIG.
When LFT = LFT1 shown in (a), the first control valve 71 is in a fully open state, and the second control valve 72 is in a fully closed state. When the drive current of the drive coil 51 is increased from this position to increase the lift amount LFT (moving the valve member 60 upward in the figure), the first control valve 72 is maintained in the fully closed state while maintaining the first control valve 72 in the fully closed state. Control valve 71 gradually closes. When the valve member 60 reaches the position of LFT = LFT2 shown in FIG. 2B, the first control valve 71 is also in the fully closed state, and LF
Until the position of T = LFT3 (FIG. 2C), both the first and second control valves 71 and 72 maintain the fully closed state.

When the lift amount LFT further increases from the position of LFT = LFT3, first, the first control valve 71 is gradually opened, and is fully opened at the position of LFT = LFT4 (FIG. 2 (d)). When the lift amount LFT further increases, the second control valve 72 starts to open, and is fully opened at the position of LFT = LFT5 (FIG. 2E).

As described above, according to the electromagnetic control valve 15 shown in FIG. 2, the first control valve 71 for opening and closing the assist air passage 16 and the second control valve 72 for opening and closing the auxiliary air passage 14 are provided.
Are integrally configured, so that the configuration can be simplified and the number of parts can be reduced.

Next, a process for determining an abnormality in the assist air passage 16 executed by the CPU of the ECU 5 will be described. FIG.
Is a flowchart of a process for determining whether or not a condition (monitor condition) for performing the abnormality determination process is satisfied. This processing is executed in the background where other high-priority processing is not executed.

First, at step S1, the engine speed N
It is determined whether or not E is within a range of predetermined upper and lower limit values NAAICKH and NAAICKL (for example, 3000 rpm and 1200 rpm, respectively), and NAAICKL <NE <NA
When AICKH, the engine coolant temperature TW is higher than a predetermined coolant temperature TWAAICK (for example, 80 ° C.) and the vehicle speed V
H is higher than a predetermined vehicle speed VAAICK (for example, 10 km / h), and the intake pipe absolute pressure PBA is equal to a predetermined pressure PBAAA.
It is determined whether it is lower than ICK (for example, 180 mmHg) (step S2), and TW> TWAAICK and VH
When> VAAICK and PBA <PBAAAICK, the change amount DTH of the throttle valve opening θTH (the difference between the previous detection value and the present detection value) is the predetermined change amount DTHAAIC.
It is determined whether K is smaller than K (for example, 0.5 degrees) (step S3). If DTH <DTHAAICK, it is determined that deceleration fuel cut (fuel supply cutoff during engine deceleration) is "1". It is determined whether or not the fuel cut flag FFC indicated by is "1" (step S4).

FIG. 5 is a flowchart of a process for determining the engine operating state for executing the deceleration fuel cut and setting the fuel cut flag FFC.
This is executed in synchronization with the generation of the C signal pulse.

First, at step S101, the throttle valve opening θTH is set to a predetermined opening θ for judging the almost fully closed state.
It is determined whether or not TIDLE (for example, once) or more, and θT
When H ≧ θTHIDLE, the absolute pressure PB in the intake pipe
It is determined whether or not A is equal to or higher than a predetermined pressure PBFC (for example, 130 mmHg) (step S102), and if PBA <PBFC, the engine speed NE becomes the predetermined speed NPBF.
It is determined whether or not CLM (for example, 1800 rpm) or less (step S103). As a result, when PBA ≧ PBFC or NE ≦ NPBFCLM, a predetermined time TFCDLY (for example, 0.5
Second) and start (step S106)
The fuel cut flag FFC is set to "0" (step S108), and the process ends. On the other hand, PBA <PB
If FC and NE> NPBFCLM, it is determined whether or not the fuel cut flag FFC has already been set to "1" (step S104). If FFC = 1, the flow proceeds to step S109 to maintain the state. . If FFC = 0 in step S104, the change amount of the intake pipe absolute pressure PBA (the difference between the previous detection value and the current detection value) DP
It is determined whether the absolute value of BACYL is equal to or greater than a predetermined change amount DPBDLY (for example, 5 mmHg) (step S10).
5) If | DPBACYL | ≧ DPBDLY and the variation in the absolute pressure PBA in the intake pipe is large, the process proceeds to step S106, and the state of FFC = 0 is maintained.

In step S105, | DPBACYL | <
If DPBDLY and the variation in the intake pipe absolute pressure PBA is small, it is determined whether or not the value of the timer tmFCDLY started in step S106 is "0" (step S107). As long as tmFCDLY> 0, FFC is performed. =
0 (step S108), and tmFCDLY = 0
Then, the fuel cut flag FFC is set to "1" (step S109), and this processing ends.

Thus, the fuel cut flag F
FC is set to “1” when the engine 1 is decelerating and the state of low load and high rotation continues for a predetermined time TFCDLY.

Returning to FIG. 4, when the answer of any of steps S1 to S4 is negative (NO), it is determined that the monitoring condition is not satisfied, and the routine proceeds to step S10, where the lift amount LFT of the electromagnetic control valve 15 is changed from LFT2 to LFT2. Value during LFT3 (value for setting both first and second control valves 71 and 72 to fully closed state)
Fully-closed flag FAAIZER that indicates what should be done
Set O to “0”. Next, step S12 described later.
A predetermined time TMCNDAA (for example, 2 seconds) is set in a down count timer tmMCDAA to be referred to in step (2) and started (step S11), and a monitor condition flag FMCNDAA is set to "0" to indicate that the monitor condition is not satisfied (step S14). This processing ends.

On the other hand, when all of the answers in steps S1 to S4 are affirmative (YES), it is indicated by "1" that the storage of the detected value (initial value) of the intake pipe absolute pressure PBA before the execution of the abnormality determination is completed. It is determined whether or not the initial value storage flag FAAIPBB (see steps S34 and S36 in FIG. 7) is "1" (step S6). As a result, if FAAIPBB = 0, the process immediately proceeds to step S8, where FAAIPBB
When B = 1 and the storage of the initial value has been completed, the engine speed NEGLMT when the engine speed NE stores the initial value of the intake pipe absolute pressure PBA (see FIG. 7, step S35; "Initial rotation speed"), that is, whether the engine rotation speed N
It is determined whether E is higher than the initial rotational speed NEGLMT-DKAAICKL and lower than the initial rotational speed NEGLMT + DKAAICKH (step S7). Where D
KAAICKL and DKAAICKH are predetermined values set to, for example, 500 rpm and 300 rpm, respectively.

If the answer to step S7 is negative (NO) and the fluctuation of the engine speed NE is large, it is determined that the monitoring condition is not satisfied, and the routine proceeds to step S10, where affirmative (Y
ES), the amount of change D in the output voltage VAGC of the generator
It is determined whether or not the absolute value of ACGF (the difference between the previous detection value and the current detection value) is greater than a predetermined change amount DACGAACK (step S8). As a result, | DACGF | ≦
If it is DACGAACK, it is further determined whether or not the air conditioner switch has been turned on / off, the power steering switch has been turned on / off, or the automatic transmission has changed from neutral to drive range or vice versa (step S9). If the answer to step S8 or S9 is affirmative (YES) and there is a change in the load applied to the engine, it is determined that the monitoring condition is not satisfied, and the process proceeds to step S10, while the answer to steps S8 and S9 is negative. If (NO) and there is no such change, the timer tmmCNDAA started in step S11
Is determined as to whether or not the value is “0”. tmmCNDAA> 0
While the fully closed flag FAAIZERO is "1".
(Step S13), the process proceeds to Step S14, and when tmCNMDAA = 0, it is determined that the monitor condition is satisfied, the monitor condition flag FMCNDAA is set to "1" (Step S15), and the process ends. .

As described above, according to the processing shown in FIG. 4, when the engine is being decelerated and the fuel is being cut and the engine operating state is relatively stable, it is determined that the monitor condition is satisfied, and the monitor condition flag FMCNDAA is set to " 1 ".

FIG. 6 shows a drive coil 51 of the electromagnetic control valve 15.
5 is a flowchart of a process for calculating a drive current ICMD to be supplied to the CPU, and this process is executed every time a TDC signal pulse is generated or every predetermined time.

In step S21, it is determined whether or not the control mode is the starting mode, that is, whether or not the cranking is being performed.
D is calculated (step S22), and this processing ends. If the engine is not in the start mode, it is determined whether or not the engine speed NE is higher than a predetermined speed NA for determining an idle state (step S23). This predetermined rotational speed NA is
The target engine speed NEOBJ in the idling state is set to a value higher than the target engine speed NEOBJ by a predetermined value. N in step S23
When E ≦ NA, the engine speed NE becomes the target engine speed N by the idle feedback mode process.
The drive current ICMD is calculated so as to match EOBJ (step S24).

If NE> NA in step S23, it is determined whether or not the fully closed flag FAAIZERO is "1" (step S25). If FAAIZERO = 0, whether or not the fully open flag FAAIOPN is "1" It is determined whether or not it is (step S26). Except during or immediately before the execution of the abnormality determination process (see step S13 in FIG. 4), the fully closed flag FAAIZERO and the fully open flag FAA
Since IOPN is both “0”, the IC corresponding to the engine speed NE or the like is executed by the non-idle control mode process.
The MD value is calculated (step S27).

On the other hand, when the fully closed flag FAAIZERO is set to "1" in step S13 of FIG. 4, the process proceeds from step S25 to step S29, where the drive current ICMD is set.
Is set to a predetermined value IAAIZERO that sets the lift amount LFT to a value between LFT2 and LFT3 (step S2).
9). Also, when the fully closed flag FAAIZERO is returned to “0” and the fully open flag FAAIOPN is set to “1” in step S39 of FIG. 7 described later, the process proceeds from step S26 to step S28, and the drive current ICMD
Is a predetermined value IAAIO with the lift amount LFT = LFT1.
Set to PEN.

FIG. 7 is a flowchart of a process for judging an abnormality in the assist air passage 16, and this process is executed in synchronization with generation of a TDC signal pulse.

First, in step S31, it is determined whether or not the monitor condition flag FMCNDAA is "1".
When AA = 1 and the monitor condition is satisfied, the end flag FDO indicating that the abnormality determination has been completed is indicated by "1".
It is determined whether NEAA (see step S46) is "1" (step S32). Then, FMCNDAA = 0
And if the monitor condition is not satisfied or FDONEAA =
1 and the abnormality determination is completed, the fully open flag FA
AIOPN and the initial value storage flag FAAIPBB are both set to “0”, and the process ends.

If FDONEAA = 0 in step S32, it is determined whether the initial value storage flag FAAIPBB is "1" (step S33). At first FAAIP
Since BB = 0, the absolute pressure PBA in the intake pipe at that time
And the engine speed NE, respectively, to the initial pressure PBAAIIB
And the initial rotation speed NEGLMT (step S
34, S35), the initial value storage flag FAAIPBB is set to "1" (step S36), and a predetermined time TFSAA (for example, 2 seconds) is set in a down count timer tmFSAA to be referred to in step S42, which will be described later, and started (step S36). S37) Fully open flag FAAIOPN
Is set to "0" (step S38), and the present process ends.

When the initial value storage flag FAAIPBB = 1, the process proceeds from step S33 to step S39, where the fully closed flag FAAIZERO is set to "0" and the fully open flag FAAIOPN is set to "1". Then
From the current intake pipe absolute pressure PBA to the initial pressure PBAAI
By subtracting B, the change amount DPBAAI is calculated (step S40), and it is determined whether the change amount DPBAAI is smaller than a predetermined change amount DPBFFSA (for example, 20 mmHg) (step S41). At first, DPBA
Since AI <DPBFSAA, the flow advances to step S42 to start the timer tmFSAA started in step S37.
Is determined whether or not the value of is “0”. At first tmFS
Since AA> 0, this processing is immediately terminated. The predetermined amount of change DPBFSAA is a small amount of change in pressure that is impossible at normal times, and is set to, for example, 20 mmHg.

Thereafter, while tmFSAA> 0, DPB
When AAI ≧ DPBFSAA, the process proceeds from step S41 to S45, where it is determined that the flow rate of the assist air passage 16 is normal, and the OK flag FOKAA is set to “1”. Then, the end flag FDONEAA is set to "1" (step S46), and the process ends.

On the other hand, when the condition of DPBAAI <DPBFSAA is continued and tmFSAA = 0, the process proceeds from step S42 to S44, where the assist air passage 16
Is determined to be abnormal, that is, an abnormality caused by clogging of the assist air passage 16 or the like is set, and an abnormality flag FFDAA indicating this is set to “1”, and the process proceeds to step S46.

FIG. 8 is a diagram for explaining a determination method based on the abnormality determination process shown in FIG. 7. The engine speed NE, the intake pipe absolute pressure PBA, and the drive current IC of the electromagnetic control valve 15 are shown.
3 shows the transition of MD. FIG. 8 shows that the engine enters the deceleration fuel cut operation state at time t1, and FIG.
Is performed, and the first control of the electromagnetic control valve 15 is performed.
And the second control valves 71 and 72 are both fully closed (FIG. 2).
(B) or (c)). At time t3 after a lapse of the predetermined time TMCNDAA from time t2, the monitoring condition flag FMCNDAA becomes "1", the absolute pressure PBA in the intake pipe at that time is stored as the initial pressure PBAAIIB, and the first control valve 71 is immediately fully opened. (FIG. 2A, the second control valve 72 is maintained in a fully closed state). If the change amount DPBAAI exceeds the predetermined change amount DPBFSAA at time t4 before the predetermined time period TFSAA elapses as shown by the solid line, it is determined that the state is normal while the time after the predetermined time TFSAA elapses as shown by the broken line. When the change amount DPBAAI at t5 is small,
It is determined to be abnormal.

As described above, according to the present embodiment, the first and second control valves 71 and 7 of the electromagnetic control valve 15 are in the deceleration fuel cut state in which the throttle valve 3 is almost fully closed.
2 are fully closed, then only the control valve 71 is fully opened, and the change amount DPBAA of the intake pipe absolute pressure PBA reflecting the air flow rate of the assist air passage 16 thereafter.
I (corresponding to the “flow rate change amount” described in the claims) is a predetermined change amount DPBFS within a predetermined time TFSAA.
If AA (corresponding to the "predetermined change amount" described in the claims) is not exceeded, it is determined that the assist air passage 16 is abnormal. Therefore, not only the assist air passage 16 but also the auxiliary air passage 14 is provided. In the assist air passage 1 without being affected by the auxiliary air passage 14
6 can be accurately determined. Further, the abnormality determination is performed in the deceleration fuel cut operation state, so that even if the amount of air supplied through the assist air passage 16 changes, the engine operation state is hardly affected.

Further, since the valve (first control valve 71) for opening and closing the assist air passage 16 and the valve (second control valve 72) for opening and closing the auxiliary air passage 14 are integrally formed, the structure is simplified. It can be simplified and the number of parts can be reduced. Furthermore, since one control signal (drive current ICMD) can control two control valves, the configuration of the control system can be simplified.

The electromagnetic control valve 15 is connected to the first control valve 7.
1 (LFT = LFT1 to LFT1)
2) is configured so that both the first and second control valves 71 and 72 have an operation area in which both of them can be opened. For example, the lift amount LF of the valve member 60 with respect to the drive current ICMD
Even when the control accuracy of T decreases, it is possible to avoid a situation in which the second control valve 72 is also opened during the abnormality determination to cause an erroneous determination. Here, LFT = LFT2 to LFT
The region of FT3, the region of LFT = LFT1 to LFT2, and the region of LFT = LFT3 to LFT5 respectively correspond to the first, second and third operation regions described in the claims.

The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the above-described embodiment, in the deceleration fuel cut state, first, the first and second control valves 71 and 72 are both fully closed, and then only the first control valve 71 is shifted to the fully open state to perform the abnormality determination. However, in the deceleration fuel cut state, first, the first control valve 71 is fully opened, the second control valve 72 is fully closed, and then only the first control valve 71 is shifted to the fully closed state. Absolute pressure PB in the intake pipe
When the change amount of A is equal to or less than a predetermined change amount, it may be determined that the abnormality is abnormal.

When the first control valve 71 is forcibly switched from the fully closed state to the fully opened state, the assist air passage 1
The flow rate change of 6 may be detected by providing a flow meter in the assist air passage 16.

The present invention is not limited to the case where the main passage is an intake passage of an internal combustion engine, and the sub passage is an assist air passage and an auxiliary air passage. The main passage is an evaporative fuel passage having the largest flow passage cross-sectional area communicating with the canister for storing and storing the evaporative fuel.
The present invention can also be applied to a case where one fuel vapor passage is used as a sub-passage and an on-off valve is provided in each passage.

[0061]

As described above, according to the first aspect of the present invention, the third opening / closing means is maintained in the closed state in the predetermined operating state of the engine in which the first opening / closing means is substantially closed. While the second opening / closing means is forcibly switched from the closed state to the open state or vice versa.
When the amount of change in the flow rate of the sub-passage is equal to or less than a predetermined value, it is determined that the first sub-passage is abnormal. Therefore, it is possible to accurately determine the abnormality of the first sub-passage without being affected by the second sub-passage. it can.

According to the second aspect of the present invention, when it is detected that the fuel supply is cut off when the engine is decelerated, the first control is performed while maintaining the second control valve closed. When the valve is forcibly switched from the closed state to the open state or vice versa, and when the amount of change in the flow rate of the assist air passage at the time of the switching is equal to or less than a predetermined amount of change, it is determined that the assist air passage is abnormal. An abnormality in the assist air passage can be accurately determined without being affected by the auxiliary air passage. Further, since the abnormality determination is performed in the fuel supply cutoff state at the time of engine deceleration, the abnormality determination can be performed in a state where there is almost no influence on the operation state of the engine.

According to the third aspect of the present invention, the flow rate of the first and second sub passages is controlled by the control valve in which the second and third opening / closing means are integrated. Since the opening / closing control of the opening / closing means is performed by one drive signal, the configuration can be simplified, the number of components can be reduced, and the configuration of the control system can be simplified.

According to the invention described in claim 4, the main passage,
Since the abnormality of the first sub-passage having the smallest maximum flow rate among the first and second sub-passages is determined, it is possible to early detect the abnormality of the passage most likely to cause clogging or the like.

According to the fifth aspect of the present invention, the abnormality determination is performed using the second operating region in which only the second opening / closing means can be opened, so that, for example, the opening / closing means in response to a drive signal of the opening / closing means. Even if the control accuracy of the opening degree is reduced, it is possible to avoid a situation in which the third opening / closing means is also in the open state during the abnormality determination, causing an erroneous determination.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an internal combustion engine and a control device thereof according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the configuration and operation of the electromagnetic control valve of FIG.

FIG. 3 is a diagram showing a relationship between a lift amount of a valve body of an electromagnetic control valve and a flow rate.

FIG. 4 is a flowchart of a process for determining an engine operation state for performing an abnormality determination.

FIG. 5 is a flowchart of a process for determining an engine operation state in which a deceleration fuel cut is performed.

FIG. 6 is a flowchart of a process for calculating a drive current of an electromagnetic control valve.

FIG. 7 is a flowchart of a process for determining an abnormality in an assist air passage.

FIG. 8 is a diagram for explaining an abnormality determination method based on the processing of FIG. 7;

[Explanation of symbols]

Reference Signs List 1 internal combustion engine 2 intake passage (main passage) 3 throttle valve (first opening / closing means) 4 throttle valve opening sensor (detection means) 5 electronic control unit (detection means, switching means,
Determination means) 7 intake pipe absolute pressure sensor (detection means) 10 engine speed sensor (detection means) 13 branch passage 14 auxiliary air passage (second sub-passage) 15 electromagnetic control valve 16 assist air passage (first sub-passage) 71 First control valve (second opening / closing means) 72 Second control valve (third opening / closing means)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G01M 15/00 F02D 33/00 318J (72) Inventor Norio Suzuki 1-4-1 Chuo, Wako-shi, Saitama Japan Honda Motor Co., Ltd. In the laboratory

Claims (5)

[Claims] 1. A main passage having a first opening / closing means, a first sub-passage and a second sub-passage bypassing the first opening / closing means, and a first sub-passage and a second sub-passage are provided. Second
And a third opening / closing means, wherein the first opening / closing means detects that the first opening / closing means is substantially closed, and the first opening / closing means is substantially closed by the detecting means. Switching means for forcibly switching the second opening / closing means from the closed state to the open state or vice versa, while maintaining the third opening / closing means in the closed state, A controller for determining that the first sub-passage is abnormal when a change in the flow rate of the first sub-passage at the time of operation of the switching means is equal to or less than a predetermined change amount. . 2. An intake passage provided with a throttle valve,
An assist air passage that bypasses the throttle valve and opens near a fuel injection valve of the engine; an auxiliary air passage that bypasses the throttle valve and is provided for controlling the engine speed; and the assist air passage. And a first control valve and a second control valve respectively provided in the auxiliary air passage, and a control device for an internal combustion engine, wherein: a detecting means for detecting a fuel supply cutoff state at the time of engine deceleration; When the detecting means detects that the fuel supply is cut off during the deceleration of the engine, the first control valve is forcibly opened from the closed state while the second control valve is kept closed. Switching means for switching to the state or vice versa; and when the amount of change in the flow rate of the assist air passage during the operation of the switching means is equal to or less than a predetermined amount of change, the assist air passage is abnormal. That the determining means and a control device for an internal combustion engine, characterized in that it comprises a. 3. The second and third opening / closing means are integrated control valves, and are configured to be able to execute opening / closing control of the second and third opening / closing means with one drive signal. The control device for an internal combustion engine according to claim 1, wherein: 4. The control device for an internal combustion engine according to claim 1, wherein a maximum flow rate of the first sub-passage is the smallest among the main passages and the first and second sub-passages. 5. The integrated control valve includes a first operating region in which the second and third opening / closing means are both in a closed state, and a second operating area in which only the second opening / closing means is in an open state. 4. The control device for an internal combustion engine according to claim 3, further comprising: an operation region of (i) and a third operation region in which both the second and third opening / closing means can be opened. 5.