JP4002379B2 - Control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an internal combustion engine, and more particularly to a control device that includes a variable valve timing mechanism that changes the valve timing of an intake valve and / or an exhaust valve and has a function of detecting an abnormality in the variable valve timing mechanism.
[0002]
[Prior art]
A variable valve timing mechanism for changing the timing of opening and closing the intake valve and the exhaust valve of the internal combustion engine during engine operation has been known (for example, Japanese Patent Publication No. 5-43947). A cam switching mechanism that changes the lift amount and opening angle of the valve in stages by switching the cam and a cam phase variable mechanism that changes the opening and closing timing of the valve steplessly.
[0003]
Also widely known is an evaporative fuel emission prevention device that has a canister that temporarily stores evaporative fuel generated in a fuel tank that supplies fuel to the internal combustion engine, and purges the evaporative fuel stored in the canister to the intake system of the internal combustion engine in a timely manner. (For example, Japanese Patent No. 2592432).
[0004]
[Problems to be solved by the invention]
In an engine equipped with the cam phase variable mechanism and the evaporated fuel release prevention device as described above, when the cam phase variable mechanism fails, for example, the following problems occur. In other words, if the cam phase becomes uncontrollable while the engine is idling and deviates from the valve timing suitable for idling, the combustion is not exhausted among the gases to be exhausted. The amount remaining in the chamber increases, and the amount of fuel to be supplied to the combustion chamber becomes smaller than normal. However, if purging of the evaporated fuel from the canister is performed on the assumption that the intake valve and the exhaust valve are operating at the correct valve timing, the air-fuel ratio becomes overrich, and the fuel supplied from the fuel injection valve by the air-fuel ratio feedback control There is a problem that the fuel supply amount control becomes practically impossible because the amount becomes extremely small. Therefore, there is a possibility that the operability of the engine is remarkably deteriorated.
[0005]
The present invention has been made paying attention to this point, and in an internal combustion engine equipped with a variable valve timing mechanism, when an abnormality occurs in the variable valve timing mechanism, an appropriate action is taken to minimize deterioration in engine operability. An object of the present invention is to provide a control device that can be suppressed to the limit.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 relates to valve timing changing means for changing the valve timing of at least one of the intake valve and the exhaust valve in accordance with the operating state of the internal combustion engine, and to the valve timing changing means. An abnormality detecting means for detecting an abnormality to be performed, a canister for adsorbing evaporated fuel generated in a fuel tank, a purge passage connecting the canister and an intake system of the engine, and provided in the middle of the purge passage, In a control device for an internal combustion engine comprising a control valve for opening and closing a purge passage and a control means for controlling the control valve, the purge control means is configured to detect when the abnormality is detected by the abnormality detection means. , Inspection Depending on the details of the abnormality The opening of the purge control valve Decrease from normal control Select whether to perform purging or to fully close the purge control valve. It is characterized by that.
Here, the “change in valve timing” includes at least a change in the valve timing (operation phase) of the valve, and further includes a change in the lift amount and / or the opening angle (valve opening period) of the valve. Good.
[0007]
According to this configuration, when an abnormality related to the valve timing changing means is detected, , Inspection Depending on the details of the abnormality The opening of the purge control valve Decrease from normal control Select whether to perform the purge operation or to fully close the purge control valve. Therefore, when an abnormality occurs in the valve timing changing means, it is possible to suppress deterioration in engine operability to a minimum.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a configuration of an internal combustion engine and its control device according to an embodiment of the present invention, and FIG. 2 is a diagram showing a configuration of a valve operation characteristic variable mechanism. In FIG. 1, reference numeral 1 denotes an internal combustion engine (hereinafter simply referred to as “engine”) having, for example, four cylinders. The engine 1 is a first valve operating characteristic that switches valve lift amounts and opening angles of intake valves and exhaust valves in two stages. A valve operating characteristic variable device 40 having a variable mechanism 41 and a second valve operating characteristic variable mechanism 42 as a cam phase variable mechanism that changes the opening / closing valve timing of the intake valve steplessly is provided.
[0009]
A throttle valve 3 is arranged in the middle of the intake pipe 2 of the engine 1. A throttle valve opening (θTH) sensor 4 is connected to the throttle valve 3, and an electric signal corresponding to the opening of the throttle valve 3 is output to an electronic control unit (hereinafter referred to as “ECU”) 5. Supply.
[0010]
The fuel injection valve 6 is provided for each cylinder in the middle of the intake pipe 2 and slightly upstream of an intake valve (not shown) between the engine 1 and the throttle valve 3. Each fuel injection valve 6 is connected to a fuel pump unit 8 provided in a sealed fuel tank 9 via a fuel supply pipe 7, and the fuel pump unit 8 includes a fuel pump, a fuel strainer, A pressure regulator whose reference pressure is atmospheric pressure or tank internal pressure is integrally configured. The fuel tank 9 is provided with a tank internal pressure sensor 15 for detecting the pressure in the fuel tank 9, that is, the tank internal pressure PTANK, and the detection signal is supplied to the ECU 5.
[0011]
The fuel injection valve 6 is electrically connected to the ECU 5, and the valve opening time is controlled by a signal from the ECU 5. An intake pipe absolute pressure (PBA) sensor 13 for detecting the intake pipe absolute pressure PBA and an intake air temperature (TA) sensor 14 for detecting the intake air temperature TA as the outside air temperature are mounted on the downstream side of the throttle valve 3 of the intake pipe 2. Has been.
[0012]
The ECU 5 is connected to a crank angle position sensor 16 that detects a rotation angle of a crankshaft (not shown) of the engine 1 and a cam angle position sensor 17 that detects a rotation angle of a camshaft (not shown). A signal corresponding to the rotation angle of the crankshaft and the rotation angle of the camshaft is supplied to the ECU 5. The crank angle position sensor 16 generates one signal pulse (hereinafter referred to as “CRK signal pulse”) and a signal pulse for specifying a predetermined angular position of the crankshaft at every constant crank angle period (for example, 30 degree period). The cam angle position sensor 17 outputs a signal pulse at a predetermined crank angle position of a specific cylinder of the engine 1 (hereinafter referred to as “CYL signal pulse”) and a top dead center (TDC) at the start of the intake stroke of each cylinder. A pulse (hereinafter referred to as “TDC signal pulse”) is generated. These signal pulses are used for various timing controls such as fuel injection timing and ignition timing, and detection of engine speed (engine speed) NE. The actual operating phase of the camshaft that drives the intake valve can be detected from the relative relationship between the TDC signal pulse output from the cam angle position sensor 17 and the CRK signal pulse output from the crank angle position sensor 16. it can.
[0013]
The engine 1 is provided with an engine water temperature sensor 18 for detecting the cooling water temperature TW, and the detection signal is supplied to the ECU 5. A three-way catalyst 20 is provided in the exhaust pipe 19, and O 2 sensors 21 and 22 are attached to an upstream position and a downstream position of the three-way catalyst 20, respectively. These O2 sensors 21 and 22 output an electrical signal corresponding to the oxygen concentration (air-fuel ratio) in the exhaust gas and supply it to the ECU 5.
[0014]
Next, the configuration of the evaporative fuel emission preventing device for preventing the evaporative fuel generated in the fuel tank 9 from being released to the atmosphere will be described. A canister 33 is connected to the fuel tank 9 via a charge passage 31, and the canister 33 is connected to the downstream side of the throttle valve 3 of the intake pipe 2 via a purge passage 32. A charge control valve 36 is provided in the middle of the charge passage 31.
[0015]
The operation of the charge control valve 36 is controlled by the ECU 5 and opens when the tank internal pressure is high, and guides the evaporated fuel in the fuel tank 9 to the canister 33. The charge control valve 36 is also opened when an abnormality is detected in the evaporated fuel release prevention device.
The canister 33 incorporates activated carbon for adsorbing the evaporated fuel in the fuel tank 9, and can communicate with the atmosphere via the atmosphere passage 37. A vent shut valve (open / close valve) 38 is provided in the middle of the air passage 37. The vent shut valve 38 is a so-called normally closed valve whose operation is controlled by the ECU 5 and is opened during refueling or during purge execution, and is closed at other times. However, the vent shut valve 38 is also opened and closed when the abnormality detection of the evaporated fuel release preventing device is executed.
[0016]
A purge control valve 34 is provided between the canister 33 and the intake pipe 2 in the purge passage 32. The purge control valve 34 is an electromagnetic valve configured such that the flow rate can be continuously controlled by changing the on-off duty ratio (the opening degree of the control valve) of the control signal. It is controlled by the ECU 5.
[0017]
According to this evaporative fuel discharge prevention device, the evaporative fuel generated in the fuel tank 9 during refueling flows into the canister 33 through the charge passage 31 and is adsorbed and stored by the adsorbent in the canister 33. When the purge control valve 34 is opened, the evaporated fuel temporarily stored in the canister 33 is taken in via the purge control valve 34 together with the outside air sucked through the atmospheric passage 37 due to the negative pressure in the intake pipe 2. It is sucked into the tube 2 and sent to each cylinder. Thus, the evaporated fuel generated in the fuel tank 9 is prevented from being released to the atmosphere.
[0018]
As shown in FIG. 2, the valve operating characteristic variable device 40 is a first valve operating characteristic variable that switches the valve lift amount and opening angle (hereinafter referred to as “first valve operating characteristic”) of the intake valve and the exhaust valve in two stages. A mechanism 41, a second valve operating characteristic variable mechanism 42 as a cam phase variable mechanism that changes the opening / closing valve timing of the intake valve steplessly, and a first valve operating characteristic suitable for high speed operation of the engine. In order to continuously change the opening / closing valve timing (hereinafter referred to as “operation phase”) of the intake valve and the first solenoid valve 43 that switches to the low-speed driving characteristic suitable for low-speed driving, the opening degree is continuously increased. A changeable second electromagnetic valve 44 is provided. Lubricating oil in the oil pan 46 is pressurized and supplied to the electromagnetic valves 43 and 44 by the oil pump 45. A specific configuration of the valve operating characteristic variable device 40 is shown, for example, in Japanese Patent Application No. 11-28618 by the present applicant.
[0019]
According to the valve operating characteristic variable device 40, the exhaust valve is driven by either the high speed operation characteristic indicated by the solid line L1 in FIG. 3 or the low speed operation characteristic indicated by the solid line L2, and the intake valve is indicated by the solid line L5 in FIG. Driven at a phase from the most advanced angle phase indicated by broken lines L3 and L4 to the most retarded angle phase indicated by alternate long and short dash lines L7 and L8, centering on the high speed operation characteristic indicated by and the low speed operation characteristic indicated by solid line L6. The
[0020]
The ECU 5 shapes input signal waveforms from various sensors, corrects the voltage level to a predetermined level, and converts an analog signal value into a digital signal value, a central processing circuit (hereinafter referred to as “CPU”). In addition to a storage means for storing a calculation program executed by the CPU, a calculation result, and the like, the fuel injection valve 6, the purge control valve 34, and an output circuit for supplying a drive signal to the valve operating characteristic variable device 40 are configured. Is done.
[0021]
The CPU of the ECU 5 controls the amount of fuel supplied to the engine 1 according to the output signals of various sensors such as the crank angle position sensor 16, the intake pipe absolute pressure sensor 13, the engine water temperature sensor 18, the O2 sensors 21 and 22, and the purge control valve. The purge fuel amount control by 34 and the valve operation characteristic control according to the engine operation state are executed, and the abnormality detection process related to the valve operation characteristic variable device 40 described below is executed.
[0022]
FIG. 4 shows a control deviation when the second valve operating characteristic variable mechanism 42 is controlled to make the operating phase CAIN of the intake valve coincide with the target phase CAINCMD, that is, an abnormality in which the actual operating phase does not match the target phase. It is a flowchart of the process to perform. This process is executed by the CPU of the ECU 5 every predetermined time.
[0023]
In step S11, it is determined whether or not the phase variable control flag FVTC indicating “1” that the phase variable control for changing the operation phase of the intake valve is being performed is “1”, and FVTC = 0. When the phase variable control is not executed, the target phase CAINCMD sets the target phase change flag FCMDCHANG indicating “1” that the predetermined value or more has changed to “0” (step S14), and the control deviation The down-count timer tmFSB used for determining that there is an abnormality (abnormality determination) and the down-count timer tmOKB used for determining that there is no control deviation (normal determination) are respectively set to a predetermined abnormality determination time TMFSB ( For example, 10 seconds) and a predetermined normal judgment time TMOKB (for example, 10 seconds) are set and started (step S15).
[0024]
If FVTC = 1 and phase variable control is being executed in step S11, it is determined whether or not the target phase change flag FCMDCHANG is “1” (step S12). If FCMDCHANG = 1, step is immediately performed. Proceed to S17. When FCMDCHANG = 0, it is determined whether or not the absolute value of the difference between the current value CAINCMD (n) and the previous value CAINCMD (n−1) of the target phase is equal to or greater than a predetermined value CMDVTFCS (for example, 5 degrees). Step S13), | CAINCMD (n) −CAINCMD (n−1) | <CMDVTFCS, and when the change amount of the target phase CAINCMD is small, the process proceeds to Step S14, while | CAINCMD (n) −CAINCMD (n− 1) When | ≧ CMDVTFS, the target phase change flag FCMDCHANG is set to “1” (step S16), and the process proceeds to step S17.
[0025]
In step S17, a lower limit value obtained by subtracting a predetermined subtraction value CAINCFSL (for example, 2 degrees) from the target phase CAINCMD whether or not the actual operation phase CAIN is within a predetermined range substantially centered on the target phase CAINCMD. It is determined whether or not it is between CAINCMD−CAINCFSL) and an upper limit value (CAINCMD + CAINCFSH) obtained by adding a predetermined addition value CAINCFSH (for example, 2 degrees) to the target phase CAINCMD. Here, the actual operation phase CAIN is detected based on the relative phase relationship between the CRK signal pulse and the TDC signal pulse as described above. That is, as shown in FIG. 8, the phase difference CAINZP between the TDC signal pulse ZP when the cam operation phase is at the most retarded position and the predetermined CRK signal pulse YP is used as the reference phase, and the advance angle from the reference phase is set. The actual operating phase CAIN is detected as a quantity. Specifically, the generation time interval TCAIN of the predetermined CRK signal pulse YP and the TDC signal pulse XP and the generation time interval CRME of the CRK signal pulse are measured, and when the CRK signal pulse is generated every 30 ° of crank angle, CAIN = CAINZP−30 × TCAIN / CRM.
[0026]
If the answer to step S17 is affirmative (YES) and the actual operation phase CAIN is within a predetermined upper and lower limit value range, the abnormality determination timer tmFSB is set to a predetermined time TMFSB and started (step S18). It is determined whether or not the value of the normal determination timer tmOKB is “0” (step S19). While tmOKB> 0, this processing is immediately terminated and remains in that state (the answer to step S17 is affirmative (YES)). When tmOKB = 0, it is determined to be normal and there is no control deviation. The normal flag FOKB indicated by “1” is set to “1”, the control deviation flag FFSDB indicated by “1” indicating that there is a control deviation is set to “0”, and the target phase change flag FCMDCHANG is set to “0”. Return (step S20), and this process is terminated.
[0027]
On the other hand, if the answer to step S17 is negative (NO), that is, if the actual operating phase CAIN is not within the range of the predetermined upper and lower limit values, the normal determination timer tmOKB is set to the predetermined time TMOKB and started (step S21). It is determined whether or not the value of the determination timer tmFSB is “0” (step S22). As long as tmFSB> 0, this process is immediately terminated and remains in that state (the answer to step S17 is negative (NO)). If tmFSB = 0, it is determined that there is an abnormality and there is no control deviation. The normal flag FOKB indicated by “1” is set to “0”, the control deviation flag FFSDB indicated by “1” is set to “1”, and the target phase change flag FCMDCHANG is set to “0”. It returns (step S23), and this process is complete | finished.
[0028]
FIG. 5 is a time chart for explaining the processing of FIG. 4, and FIGS. 5A to 5C show a normal case, and FIGS. 4D to 6F show an abnormal case. That is, when the actual operation phase CAIN follows with a slight delay corresponding to the change of the target phase CAINCMD as shown in FIG. 5A, the timer tmOKB = 0 at time t1 and normality is determined. ((B) in the figure). On the other hand, when the actual operation phase CAIN does not follow quickly in response to the change in the target phase CAINCMD as shown in FIG. 4D, the timer tmFSB = 0 at time t2, and the abnormality determination, that is, the control deviation Judgment is made.
[0029]
FIG. 6 is a flowchart of the process for detecting the disconnection of the solenoid of the solenoid valve 44, and this process is executed by the CPU of the ECU 5 every predetermined time.
In step S31, it is determined whether the duty ratio DDOUT of the signal for driving the solenoid of the solenoid valve 44 is larger than a predetermined duty ratio DDVTFSLM (for example, 50%). If DDOUT> DDVTFSLM, the solenoid of the solenoid valve 44 is switched. It is determined whether or not the supplied current value IACTVTC is smaller than a predetermined current value IACTFSLM (for example, 450 mA) (step S32). When DDOUT ≦ DDVTFSLM or IACTVTC ≧ IACTFSLM, the downcount timer tmFSA is set to a predetermined time TFSA (for example, 5 seconds) and started (step S33), and this process is terminated.
[0030]
On the other hand, if the answer to steps S31 and S32 is both affirmative (YES), that is, if DDOUT> DDVTFSLM and IACTVTC <IACTFSLM, the current value IACTVTC is small even though the duty ratio DDOUT of the drive signal is large. It is determined that the value of the timer tmFSA is “0” (step S34). While tmFSA> 0, this processing is immediately terminated. When tmFSA = 0, the determination of disconnection is confirmed, and the disconnection flag FFSDA indicating “1” is set to “1” (step S35). ), This process is terminated.
[0031]
FIG. 7 is a flowchart of processing for detecting a case where there is a misalignment, that is, a case where the cam shaft mounting position is deviated from the normal position and the phase of the TDC signal pulse is deviated from the original. It is executed by the CPU of the ECU 5 immediately after the switch is turned on.
[0032]
In step S41, when the actual operation phase CAIN is at the most retarded angle phase CAINZP (when the valve operation characteristics are the characteristics of the one-dot chain lines L7 and L8 in FIG. 3), that is, when the cam phase variable control is not executed. It is determined whether or not the operating phase CAIN0 (center value is 0) is within the range of the predetermined upper limit value CAIN0H and the predetermined lower limit value CAIN0L. If the answer is negative (NO), that is, CAIN> CAIN0H or CAIN <CAIN0L. If it is, it is determined that there is a misalignment, the misalignment flag FFSDC indicated by “1” is set to “1” (step S42), and this process ends.
[0033]
FIG. 9 is a flowchart of a process for controlling the opening degree of the purge control valve 34, and this process is executed by the CPU of the ECU 5 every predetermined time.
In steps S51 to S53, it is determined whether or not the disconnection flag FFSDA, the control deviation flag FFSDB, and the alignment deviation flag FFSDC set in the processes of FIGS. 4, 6 and 7 are set to “1”. When it is “0”, that is, when no abnormality is detected, according to the engine operating state (for example, the purge control valve opening is calculated according to the engine speed NE and the intake pipe absolute pressure PBA). Normal purge control is performed (step S54).
[0034]
On the other hand, when FFSDA = 1 and disconnection of the solenoid of the solenoid valve 44 is detected, the opening of the purge control valve 34 is decreased from the normal control time, and the purge is executed (step S56), and FFSDB = 1 or When FFDC = 1 and a control deviation or alignment deviation is detected, the purge control valve 34 is fully closed to stop the purge (step S55).
When FFSDC = 1 and an alignment shift is detected, the purge amount may be reduced according to the shift amount instead of stopping the purge.
[0035]
As described above, in this embodiment, when an abnormality is detected in the second valve operating characteristic variable mechanism and the electromagnetic valve 44 for controlling the second valve operating characteristic variable mechanism, the purge amount is decreased or the purge is stopped. For example, in an idle state where the most retarded phase is desirable as the intake valve operating phase, it is possible to avoid the problem that the fuel amount cannot be controlled by performing a normal purge while the actual operating phase is shifted in the advance direction. it can. As a result, it is possible to minimize the deterioration of operability when an abnormality occurs in the variable valve operation characteristic mechanism.
[0036]
In the present embodiment, the following abnormality (deterioration) detection processes from 1) to 10) are further performed. However, the above-described solenoid valve disconnection (FFSDA = 1), control deviation (FFSDB = 1), or alignment. When any one of the deviations (FFSDC = 1) is detected, it is desirable not to execute the following 2), 3), 5) and 7) to 10) abnormality (deterioration) detection processing. This is because abnormality detection may not be performed accurately. In other words, when any of the flags FFSDA, FFSDB, or FFSDC is “1”, the following 1) abnormality detection process of the O2 sensor 21, 4) abnormality detection process of the fuel injection valve 6, and 6) the O2 sensor Only the deterioration detection process 22 is executed.
[0037]
1) O2 sensor 21 abnormality detection processing
In this process, when the sensor output is larger than a predetermined upper limit value, or when the sensor output while the fuel supply to the engine is cut off indicates a rich air-fuel ratio, it is determined that the circuit is disconnected, and a state in which the sensor output indicates a lean air-fuel ratio If it continues for more than a certain time, it is determined that there is a short circuit or abnormal output.
[0038]
2) Abnormal detection processing of the absolute pressure sensor 13 in the intake pipe
In this process, the predicted intake pipe absolute pressure calculated based on the throttle valve opening θTH detected by the throttle valve opening sensor 4 and the engine speed NE detected by the crank angle position sensor 16 and the sensor output are shown. An abnormality is detected by comparing with the intake pipe absolute pressure PBA.
[0039]
3) Throttle valve opening sensor 4 abnormality detection process
In this process, the estimated throttle valve opening calculated based on the intake pipe absolute pressure PBA detected by the intake pipe absolute pressure sensor 13 and the engine rotational speed NE detected by the crank angle position sensor 16 and the sensor output are shown. An abnormality is detected by comparing the throttle valve opening θTH.
[0040]
4) Abnormality detection processing of the fuel injection valve 6
In this process, when the parameter value calculated based on the air-fuel ratio correction coefficient KO2 set according to the outputs of the O2 sensors 21 and 22 is out of the predetermined range, the fuel injection valve 6 is leaked or clogged. Determined.
[0041]
5) O2 sensor 21 deterioration detection process
In this process, sensor deterioration is detected based on the inversion cycle of the sensor output when the fuel supply amount is feedback controlled according to the output of the O2 sensor 21. When a proportional oxygen concentration sensor whose output is substantially proportional to the air-fuel ratio is used instead of the O2 sensor 21, deterioration is detected based on the change in sensor output when the control air-fuel ratio is changed. .
[0042]
6) O2 sensor 22 deterioration detection process
In this process, if the sensor output is inverted, it is determined that the sensor output is normal. If the sensor output is not inverted, deterioration is detected based on a change in the sensor output when the control air-fuel ratio is changed.
[0043]
7) Deterioration detection processing of the three-way catalyst 20
In this process, the deterioration is detected based on the inversion period of the output of the O2 sensor 22 when the control air-fuel ratio is vibrated at a predetermined period.
8) Abnormality detection processing of the engine water temperature sensor 18
In this process, an abnormality is detected based on the sensor output after the elapse of a predetermined time from the start completion point.
[0044]
9) Thermostat abnormality detection processing
In this process, an abnormality in the thermostat that opens and closes the cooling water channel is detected by comparing the degree of increase in the engine water temperature TW with the degree of increase in the engine water temperature estimated from the fuel supply amount. When the actual increase degree is larger than the estimated increase degree, it is determined that the thermostat is normal (not open). The thermostat automatically opens and closes a cooling water channel that circulates engine cooling water according to the engine cooling water temperature, and is provided to close the cooling water channel and promote engine temperature rise during cold start of the engine. ing.
[0045]
10) Abnormality detection processing of the evaporated fuel release prevention device
In this process, the presence or absence of leakage of the fuel tank 9, the canister 33, etc. is detected by monitoring the tank internal pressure PTANK while opening and closing the purge control valve 34, the charge control valve 36, and the vent shut valve 38.
[0046]
In the embodiment described above, the valve operating characteristic variable device 40 and the ECU 5 constitute the valve timing changing means, and the ECU 5 constitutes the abnormality detecting means and the purge control means. More specifically, the processes of FIGS. 4, 6 and 7 correspond to the abnormality detecting means, and the process of FIG. 9 corresponds to the purge control means.
[0047]
The present invention is not limited to the embodiment described above, and various modifications can be made. For example, in the above-described embodiment, the second valve operating characteristic variable mechanism 42 can change only the operating phase of the intake valve. However, only the operating phase of the exhaust valve or the operating phases of the intake valve and the exhaust valve are used together. It may be changeable.
[0048]
In the above-described embodiment, an example in which the abnormality of the second valve operation characteristic variable mechanism 42 and the electromagnetic valve 44 is detected is shown. However, the abnormality of the first valve operation characteristic variable mechanism 41 and the electromagnetic valve 43 is detected, and the result Accordingly, the same fail-safe process may be performed in the purge control. As abnormality detection in that case, an abnormality in which the operation characteristic of the intake valve or the exhaust valve does not become a characteristic as the switching command and a disconnection of the solenoid of the solenoid valve 43 are detected.
[0049]
【The invention's effect】
As described above in detail, according to the present invention, when an abnormality relating to the valve timing changing means is detected, , Inspection Depending on the details of the abnormality The opening of the purge control valve Decrease from normal control Select whether to perform the purge operation or to fully close the purge control valve. Therefore, when an abnormality occurs in the valve timing changing means, it is possible to suppress deterioration in engine operability to a minimum.
[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 showing a configuration of a valve operating characteristic variable device.
FIG. 3 is a graph showing valve operating characteristics.
FIG. 4 is a flowchart of processing for detecting a control deviation of the variable valve operating characteristic device.
FIG. 5 is a time chart for explaining the processing of FIG. 4;
FIG. 6 is a flowchart of processing for detecting disconnection of a solenoid valve.
FIG. 7 is a flowchart of processing for detecting camshaft misalignment.
FIG. 8 is a view for explaining the definition of the actual operating phase (CAIN) of the camshaft.
FIG. 9 is a flowchart of a process for controlling the opening degree of the purge control valve.
[Explanation of symbols]
1 Internal combustion engine
2 Intake pipe
5 Electronic control unit (valve timing changing means, abnormality detection means, purge control means)
9 Fuel tank
16 Crank angle position sensor
17 Cam angle position sensor
31 Charge passage
32 Purge passage
33 Canister
34 Purge control valve
40 Valve operation characteristic variable device (valve timing changing means)
41 First valve operating characteristic variable mechanism
42 Second valve operating characteristic variable mechanism
43, 44 Solenoid valve

Claims (1)

Generated in the fuel tank, valve timing changing means for changing the valve timing of at least one of the intake valve and the exhaust valve according to the operating state of the internal combustion engine, an abnormality detecting means for detecting an abnormality related to the valve timing changing means, A canister for adsorbing evaporated fuel, a purge passage connecting the canister and an intake system of the engine, a purge control valve provided in the middle of the purge passage, for opening and closing the purge passage, and the purge control valve In a control device for an internal combustion engine provided with a purge control means for controlling,
Said purge control means when the abnormality is detected by the abnormality detection means, according to the content of abnormality was detected, performing a purge opening degree of the purge control valve is decreased from the normal control If a control apparatus for an internal combustion engine, wherein you to select a case where the purge control valve is fully closed.

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