JP2005330810A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely start an engine while preventing emission of unburned fuel when operating angle and center angle are out of characteristics suitable for start at a time of engine stop due to engine stall or the like. <P>SOLUTION: The operating angle and the center angle automatically return to the characteristics suitable for start at a time of normal engine stop, but the same get out of the characteristics suitable for start and effective compression ratio can not be secured and start becomes difficult at a time of abnormal stop due to engine stall. In this invention, a flag Fenst is stored as 1 when engine stop is an abnormal stop. A fuel injection stop flag Ffcut is kept as 1 (step 14) until a predetermined time Td passes (step 13) if the flag Fenst is 1 (step 12) at a time of next start. Consequently, fuel injection is kept stopped until the predetermined time passes after start of cranking, and fuel injection is started after the operating angle and the center angle get in the characteristics suitable for start. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention controls an internal combustion engine that includes a first variable valve mechanism that changes the operating angle of the intake valve and a second variable valve mechanism that changes the central angle of the operating angle as the valve operating mechanism of the intake valve. More particularly, the present invention relates to a control device that performs start control of an internal combustion engine.

  In a gasoline engine, the intake air amount is generally controlled by controlling the opening of a throttle valve provided in the intake passage. As is well known, this type of system has a particularly small throttle valve opening. There is a problem that the pumping loss is large at low load. In contrast, attempts have been made to control the intake air amount without depending on the throttle valve by changing the opening / closing timing of the intake valve and the lift amount.

  Patent Document 1 has been previously proposed by the present applicant. As a variable valve mechanism for an intake valve, a first variable valve that can simultaneously and continuously expand and reduce the lift and operating angle of the intake valve. A mechanism (lift / operating angle variable mechanism) and a second variable valve mechanism (phase variable mechanism) that continuously delays the position of the central angle of the operating angle. An intake valve drive control device for an internal combustion engine is disclosed in which the intake air amount is controlled by changing the opening / closing timing of the intake valve.

  Thus, in the intake valve drive control device provided with two variable valve mechanisms, each target value is given according to the operating state, and each variable valve mechanism is controlled along this.

Patent Document 2 discloses a fuel injection control technique at the time of start-up in an internal combustion engine having a variable valve mechanism that can variably control the valve timing (open / close timing) of the intake and exhaust valves. In consideration of the case where the valve timing has not been returned, in one embodiment, the actual valve timing is sequentially detected at the start, and the fuel injection is permitted when the valve timing reaches a predetermined valve timing. ing. In another embodiment, the start of fuel injection is delayed from the start of cranking by a time set according to the temperature of the engine.
JP 2002-256905 A JP-A-9-195840

  In the configuration in which the intake air amount is controlled mainly by the variable control of the operation angle and the center angle of the intake valve as in the above-mentioned Patent Document 1, the valve lift characteristic defined from the operation angle and the center angle at the start of the engine is If the predetermined characteristics suitable for starting are not maintained, starting is impossible or difficult even when cranking. For example, in the configuration including the two variable valve mechanisms as described above, in the partial load region, the operation angle is controlled to be relatively small and the central angle is controlled to the advanced position, and the intake valve closing timing is Although it is at a position advanced from the bottom dead center, the operating angle or center angle could not be restored to the specified starting characteristics when the engine suddenly stopped due to engine stall from this operating state. Then, the intake valve closing timing becomes an advance side from the position suitable for starting, and even if cranking is performed at the time of starting, an appropriate effective compression ratio cannot be secured, and there is a possibility that the starting does not immediately occur. Note that the operating angle and the central angle gradually approach the target values due to cranking, so that the engine can be started anyway. Therefore, if fuel injection is started in the meantime, unburned fuel may be discharged, and the air-fuel mixture in the cylinder becomes excessive, which may make starting difficult.

  On the other hand, in the configuration as in Patent Document 1 including the first variable valve mechanism that changes the operating angle of the intake valve and the second variable valve mechanism that changes the central angle of the operating angle, the actual central angle is generally used. Is difficult to detect in real time. For example, the phase difference between the crankshaft and the drive shaft can only be detected once every 720 ° CA. Therefore, as in the first embodiment of Patent Document 2, in the technology based on the detection of the actual valve timing, the injection timings of some cylinders come before the actual center angle is detected. Thus, the processing in such a case is not disclosed in Patent Document 2. Further, as in the second embodiment of Patent Document 2, if the fuel injection is always prohibited for a certain period, the operation angle and the central angle are changed from the beginning when the internal combustion engine is stopped normally and at the next start. Even when the value is appropriate, the start of the engine is delayed, which is not preferable.

  The present invention includes a first variable valve mechanism that can continuously change the operating angle of the intake valve, and a second variable valve mechanism that can continuously change the central angle of the operating angle. An internal combustion engine comprising: a fuel injection device configured to control an intake air amount by changing an operating angle and a central angle of an intake valve; and a fuel injection device that injects and supplies fuel at a predetermined fuel injection timing. When the internal combustion engine is started, the fuel injection stop period after the start of cranking is changed based on the history of the previous stop when the internal combustion engine is started. Yes.

  That is, at the time of starting, referring to the history at the time of the previous stop, if it is normal stop, it is considered that the operating angle and center angle of the intake valve are suitable for starting, and after starting cranking, Perform fuel injection control. Therefore, fuel injection is performed at a predetermined injection timing after cylinder discrimination is completed. On the other hand, if the previous rotation stop of the internal combustion engine was an abnormal stop due to an engine stall or the like, it may take time until the operating angle and center angle of the intake valve are controlled to values suitable for starting. Therefore, a long fuel injection stop period is given. Since the control of the first and second variable valve mechanisms is started simultaneously with the start of cranking, even if the operating angle and center angle deviate from the values suitable for starting at the initial stage due to an abnormal stop, the target is gradually increased during cranking. Approach the value. Therefore, fuel injection is started when the effective compression ratio in the cylinder is sufficiently secured and ignition combustion is possible.

  In one aspect of the present invention, when the rotation of the internal combustion engine is stopped, at least in the case of an abnormal stop, the operating angle and the central angle by the first and second variable valve mechanisms are stored and held as part of the history, The fuel injection stop period is set based on the operating angle and center angle of the history.

  In another embodiment, when the previous rotation stop of the internal combustion engine was an abnormal stop, the fuel injection is stopped and detected until the detection of the actual operating angle and the central angle is completed at the start. The fuel injection stop period is set on the basis of the initial divergence amount between the operation angle and the central angle and the respective target values when the operation is completed.

  In another embodiment, when the previous rotation stop of the internal combustion engine was an abnormal stop, the fuel injection is stopped and detected until the detection of the actual operating angle and the central angle is completed at the start. The fuel injection is stopped until the difference between the operating angle and the central angle and the respective target values falls within a predetermined allowable range.

  Here, when the atmospheric temperature is high, ignition combustion is possible at a stage where the effective compression ratio is lower. Further, when the internal combustion engine temperature such as the cooling water temperature or the lubricating oil temperature is low, the viscosity of the lubricating oil is high, and the operating speed of the first and second variable valve mechanisms at the initial stage of cranking decreases. Therefore, it is desirable to correct the fuel injection stop period based on these temperatures.

  When the fuel injection is stopped until the deviation between the detected operating angle and center angle and each target value falls within a predetermined tolerance, the tolerance of the deviation is set to the atmospheric temperature or the internal combustion engine. You may make it correct | amend based on engine temperature.

  According to this invention, if the previous rotation stop of the internal combustion engine is a normal stop when the internal combustion engine is started, the fuel injection is started immediately after the cranking starts, and the fuel injection is started quickly without unnecessary delay. be able to. Also, for example, when the internal combustion engine is suddenly stopped without being operated by the driver due to an engine stall or the like, in the subsequent restart, the operating angle and the central angle become values suitable for starting. Since the fuel injection is started after that, the unburned fuel is reliably prevented from being discharged, and the startability deterioration due to the over-concentration of the air-fuel ratio can be avoided.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram showing a system configuration of a control apparatus for an internal combustion engine according to the present invention. The internal combustion engine 1 has an intake valve 3 and an exhaust valve 4, and a valve operating mechanism of the intake valve 3. As described above, the first variable valve mechanism (VEL) 5 capable of continuously expanding and reducing the lift / operating angle of the intake valve 3 and the first capable of continuously delaying the central angle of the operating angle. Two variable valve mechanisms (VTC) 6 are provided. The intake passage 7 is provided with an electronically controlled throttle valve 2 whose opening degree is controlled by an actuator such as a motor. Here, the throttle valve 2 is used only for generating a slight negative pressure (for example, −50 mmHg) necessary for processing blow-by gas in the intake passage 7 and adjusting the intake air amount. Is basically performed by changing the valve lift characteristics of the intake valve 3 by the first and second variable valve mechanisms 5 and 6. That is, a substantial throttle-less operation that does not depend on the throttle valve opening for adjusting the intake air amount is realized. The first and second variable valve mechanisms 5 and 6 and the electronic control throttle valve 2 are controlled by the control unit 10.

  Further, a fuel injection valve 8 is disposed in the intake passage 7 as a fuel injection device, and an amount of fuel corresponding to the intake air amount adjusted by the intake valve 3 as described above is injected from the fuel injection valve 8. Is done. Accordingly, the output of the internal combustion engine 1 is controlled by adjusting the intake air amount by the first and second variable valve mechanisms 5 and 6.

  The control unit 10 includes an accelerator opening signal APO from an accelerator opening sensor 11 provided on an accelerator pedal operated by a driver, and an engine rotation speed signal Ne from an engine rotation speed sensor (crank angle sensor) 12. , The intake air amount signal from the intake air amount sensor 13 and the like are input, and based on these signals, the control unit 10 determines the fuel injection amount, ignition timing, throttle valve opening, operating angle target value, center A target angle value and the like are calculated to control the fuel injection valve 8, the spark plug 9, the throttle valve 2, the first and second variable valve mechanisms 5, 6, and the like. Also, a starter motor (not shown) is provided, and when starting the engine, predetermined start-up control including cranking is executed based on an input from a starter switch (ignition key switch) (not shown).

  FIG. 2 is an explanatory diagram showing the configuration of the first and second variable valve mechanisms 5 and 6. The mechanical structure of the first variable valve mechanism 5 and the second variable valve mechanism 6 is known, and for example, has the same structure as the device described in Patent Document 1 described above. Therefore, only the outline will be described.

  The first variable valve mechanism 5 that variably controls the lift / working angle is rotatably supported by a drive shaft 22 driven by a crankshaft of the internal combustion engine 1, an eccentric cam 23 fixed to the drive shaft 22. A control shaft 32, a rocker arm 26 that is swingably supported by an eccentric cam portion 38 of the control shaft 32, and a swing cam 29 that contacts the tappet 30 of the intake valve 3. 23 and the rocker arm 26 are linked by a link arm 24, and the rocker arm 26 and the swing cam 29 are linked by a link member 28.

  The rocker arm 26 is supported at its substantially central portion by the eccentric cam portion 38 so as to be swingable, and the arm portion of the link arm 24 is linked to one end portion thereof via a connecting pin 25. The upper end portion of the link member 28 is linked to the end portion via a connecting pin 27. The eccentric cam portion 38 is eccentric from the axis of the control shaft 32, and accordingly, the rocking center of the rocker arm 26 changes according to the angular position of the control shaft 32.

  The swing cam 29 is rotatably supported by being fitted to the outer periphery of the drive shaft 22, and a lower end portion of the link member 28 is linked to an end portion extending laterally via a connecting pin 37. ing. On the lower surface of the swing cam 29, a base circle surface concentric with the drive shaft 22 and a cam surface extending in a predetermined curve from the base circle surface are continuously formed. These base circle surface and cam surface come into contact with the upper surface of the tappet 30 according to the swing position of the swing cam 29.

  The control shaft 32 is configured to rotate within a predetermined angle range by a lift / operating angle control actuator 33 provided at one end. The lift / operating angle control actuator 33 is composed of, for example, an electric motor that drives the control shaft 32 via the worm gear 35, and is controlled by a control signal from the control unit 10. The rotation angle of the control shaft 32 is detected by a control shaft sensor 34. The control shaft sensor 34 is composed of, for example, a rotary potentiometer that generates a sensor output corresponding to the rotation angle of the control shaft 32, and can detect the rotation position of the control shaft 32 and the actual lift / operation angle in real time. Is possible.

  According to the first variable valve mechanism 5, the lift and operating angle of the intake valve 3 are continuously expanded and reduced simultaneously according to the rotational angle position of the control shaft 32. With the change in size, the opening timing and closing timing of the intake valve 3 change substantially symmetrically. Since the magnitude of the lift / operating angle is uniquely determined by the rotation angle of the control shaft 32, the actual lift / operating angle at that time is indicated by the detected value of the control shaft sensor 34.

  In this embodiment, the position where the lift / operating angle is minimum corresponds to the starting operating angle suitable for starting, and if the engine is stopped normally by the key-off operation of the driver, the accelerator opening As the engine speed decreases, the engine stops naturally in a state where it has returned to the vicinity of the operating angle at the time of start.

  On the other hand, the second variable valve mechanism 6 that variably controls the center angle is configured such that the sprocket 42 provided at the front end portion of the drive shaft 22 is relative to the sprocket 42 and the drive shaft 22 within a predetermined angle range. And a phase control actuator 43 that rotates in a rotating manner. The sprocket 42 is linked to the crankshaft via a timing chain or timing belt (not shown). In the present embodiment, the phase control actuator 43 is a hydraulic rotary actuator, and is controlled by a control signal from the control unit 10 via a hydraulic control valve (not shown). The action of the phase control actuator 43 causes the sprocket 42 and the drive shaft 22 to rotate relative to each other, thereby delaying the lift center angle in the valve lift. That is, the lift characteristic curve itself does not change, and the whole advances or retards. This change can also be obtained continuously. The control state of the second variable valve mechanism 6 is detected by a drive shaft sensor 36 that responds to the rotational position of the drive shaft 22.

  Here, the drive shaft sensor 36 is composed of, for example, a non-contact type sensor using a Hall IC element, and detects a slit of a circular plate (not shown) attached to the end of the drive shaft 22. The control unit 10 compares the crank angle at the timing at which this slit is detected with a reference crank angle (for example, a crank angle corresponding to the most retarded angle state of the second variable valve mechanism 6), so that the drive shaft for the crankshaft is A rotational phase difference of 22 (this corresponds to the actual center angle) can be obtained. Here, since the drive shaft 22 makes one rotation at 720 ° CA, the actual center angle is basically detected every 720 ° CA. At the time of starting, since the crank angle cannot be accurately recognized until the cylinder discrimination is completed, the actual center angle detection is further delayed.

  In the present embodiment, the center angle at the most retarded angle is the center angle at the start suitable for starting, and, similar to the aforementioned operating angle, if the engine is normally stopped by the driver's key-off operation, As the accelerator opening and the engine speed decrease, the engine naturally stops near the center angle when starting, and the engine stops.

  Next, control at the start of the internal combustion engine configured as described above will be described with reference to FIGS.

  FIG. 3 is a flowchart showing a routine for storing and holding the history when the engine is stopped, which is repeatedly executed, for example, every 10 ms during the operation of the engine. First, at step 1, the engine speed Ne is read, and at step 2, it is determined whether the internal combustion engine 1 has changed from the operating state to the stop based on the engine speed Ne. If it is determined that the engine is stopped, the process proceeds to step 3 to determine whether an ignition switch (not shown) is OFF. If the ignition switch is OFF, it is determined that the engine is normally stopped by the driver's key-off operation, and the flag Fenst is set to 0 in step 4. On the other hand, when the engine is stopped while the ignition switch is ON, it is determined that the engine has stopped abnormally due to an unintended engine stall, and the flag Fenst indicating an abnormal stop is set to 1 in step 5. The state of the flag Fenst indicating the history at the time of stop is maintained as it is even after the ignition switch is turned off.

  FIG. 4 is a flowchart showing a routine for stopping fuel injection at the time of starting, and this is also repeatedly executed, for example, every 10 ms. In step 10, it is determined whether a starter switch (not shown) is reversed from OFF to ON. If YES, the process proceeds to step 11 and a timer T is started. If NO, step 11 is skipped. Therefore, step 11 passes only the first time when the engine is started. Next, in step 12, the state of the flag Fenst indicating the stop history is determined. If the flag Fenst is 0, the process proceeds to step 15 to set the fuel injection stop flag Ffcut to 0. If the flag Fenst is 1, it is determined in step 13 whether or not the value of the timer T is less than a predetermined value (predetermined time) Td. The process proceeds to step 14 until the predetermined value Td is reached, and the fuel injection stop flag Ffcut is reached. Is 1. That is, if the history at the previous stop is an abnormal stop, the flag Ffcut is set to 1 for a predetermined time Td. Note that cranking of the internal combustion engine 1 is started by a starter motor (not shown) in association with the starter switch being reversed from OFF to ON.

  FIG. 5 is a flowchart showing a routine of fuel injection amount control, which is also repeatedly executed, for example, every 10 ms. In step 100, the intake air amount Qa and the engine speed Ne are read. In step 101, the basic fuel injection amount Tp is calculated as “Tp = K × Qa / Ne” using an appropriate constant K. In step 102, the fuel injection amount Ti is obtained by multiplying various correction coefficients COEF. Since these processes are techniques well known to those skilled in the art and are not the main part of the present invention, detailed description thereof will be omitted. Next, in step 103, the state of the fuel injection stop flag Ffcut is determined. If the flag Ffcut is 1, the fuel injection amount Ti is set to 0 in step 104. Eventually, fuel injection is performed from the fuel injection valve 8 of each cylinder at a predetermined injection timing by a fuel injection routine (not shown) along the fuel injection amount Ti thus determined.

  Accordingly, in the case of a start after a normal engine stop, the flag Ffcut is 0 from the beginning, so that the fuel injection is started immediately after the cranking is started. More specifically, after completion of cylinder discrimination (for example, detection that the reference cylinder has reached compression top dead center) by a crank angle sensor (not shown), when the injection timing of any cylinder has arrived, Fuel is supplied by injection.

  On the other hand, in the case of starting after an abnormal stop, the flag Ffcut is set to 1 from the start of cranking to the lapse of the predetermined time Td, and fuel injection is substantially prohibited. Therefore, even if the operating angle and the central angle are not initially located at the starting operating angle and the starting central angle suitable for starting due to an abnormal stop, it is effective by approaching the starting operating angle and the starting central angle by cranking. The fuel injection is started when the compression ratio is sufficiently obtained, so that the fuel injection can be started reliably and the discharge of unburned fuel is suppressed. In the configuration of the above embodiment, the control shaft 32 of the first variable valve mechanism 5 is rotationally driven by the lift / operating angle control actuator 33 made of an electric motor, so that it can be started even after an abnormal stop. Sometimes the operating angle quickly changes to the target operating angle (ie, the starting operating angle). On the other hand, since the phase control actuator 43 of the second variable valve mechanism 6 is hydraulically driven, a relatively large delay occurs before the change to the target center angle at low oil pressure during cranking. The predetermined time Td is set mainly in consideration of the time required for changing the central angle.

  Next, referring to FIG. 6, a second embodiment of the control at the time of starting will be described. The routine shown in the flowchart of FIG. 6 is combined with the routine of FIG. 3 and FIG. 5 described above instead of the routine of FIG. 4 described above, and is repeatedly executed, for example, every 10 ms. First, in step 20, the state of the flag Fenst indicating the history of stoppage is determined. If the flag Fenst is 0, the process proceeds to step 27, and the flag Ffcut for stopping fuel injection is set to 0. If the flag Fenst is 1, the process proceeds to step 21 to determine whether or not the timer T has not been started. Since the first time is YES, the process proceeds to step 22, and the deviation amount between the actual operating angle and center angle at that time and the target starting operating angle and starting center angle has not been detected or has been detected. Determine whether. In the configuration of the above embodiment, as described above, the operating angle is detected in real time by the control axis sensor 34. Therefore, the deviation amount of the operating angle can be detected immediately after the cranking is started. However, since the center angle is detected for the first time when the crankshaft has rotated several times due to cranking, detection of the amount of deviation from the center angle at start-up is also completed after the start of cranking. Until the detection of the deviation amount is completed, the process proceeds from step 22 to step 23, and the fuel injection stop flag Ffcut is set to 1. Thus, as described above, fuel injection is substantially prohibited by the routine of FIG.

  When the crankshaft rotates to some extent and the actual center angle and thus the deviation amount is detected, the process proceeds from step 22 to step 24, and the value of the predetermined time Td is set based on the initially detected deviation amount. In step 25, the timer T is started. Thereafter, the process proceeds from step 21 to step 26 where it is determined whether the value of the timer T is less than a predetermined value (predetermined time) Td, and the fuel injection stop flag Ffcut is set to 1 until the predetermined time Td is reached. After reaching the time Td, the fuel injection stop flag Ffcut is set to zero. In this routine, the determination of whether or not the detection of the divergence amount is completed substantially doubles the determination of the start of cranking, and therefore the determination of the starter switch ON is unnecessary.

  FIG. 7 shows an example of a map used for setting the predetermined time Td in step 24 described above. As shown in this figure, based on both the deviation amount of the operating angle and the deviation amount of the center angle (phase), basically, the characteristic that the predetermined time Td becomes longer as the respective deviation amounts are larger. The predetermined time Td is determined. As in this embodiment, when restarting after an abnormal stop, it is possible to start fuel injection at a more appropriate time by setting the predetermined time Td according to the actual amount of deviation. Become.

  Next, based on FIG. 8 and FIG. 9, a third embodiment of the control at the time of starting will be described. The routine of FIG. 8 is used instead of the routine of FIG. 3 described above, and the routine of FIG. 9 is used instead of the routine of FIG. 4 described above, and these are combined with the routine of FIG. It is. All routines are repeatedly executed, for example, every 10 ms.

  The routine shown in FIG. 8 is basically the same as that shown in FIG. 3. In step 1, the engine speed Ne is read. In step 2, the internal combustion engine 1 is stopped from the operating state based on the engine speed Ne. Determine if it has changed. If it is determined that the engine is stopped, the process proceeds to step 3 to determine whether or not an ignition switch (not shown) is OFF. If the ignition switch is OFF, it is determined that the engine is normally stopped due to the driver's key OFF operation. At 4, the flag Fenst is set to 0. On the other hand, if the engine is stopped with the ignition switch turned on, it is determined that the engine has stopped abnormally due to an unintended engine stall, and in step 6, the flag Fenst indicating an abnormal stop is set to 1. In this embodiment, at the same time, the values of the operating angle and the central angle (phase) at that time are stored and retained as a history of stopping. These histories are held as they are even after the ignition switch is turned off.

  In the routine of FIG. 9, first, in step 40, the state of the flag Fenst indicating the stop history is determined. If the flag Fenst is 0, the process proceeds to step 47, and the flag Ffcut for stopping fuel injection is set to 0. To do. If the flag Fenst is 1, the routine proceeds to step 41, where it is determined whether the timer T has not been started. Since the first time is YES, the process proceeds to step 42, and the operating angle and center angle at the previous stop stored as the history at the time of stopping are read. In step 43, based on these operating angles and center angle, the predetermined time Td Set the value of. In step 44, the timer T is started and the process proceeds to step 45 where the fuel injection stop flag Ffcut is set to 1. Thus, as described above, fuel injection is substantially prohibited by the routine of FIG. Thereafter, the process proceeds from step 41 to step 46, where it is determined whether the value of the timer T is less than a predetermined value (predetermined time) Td, and the fuel injection stop flag Ffcut is set to 1 until the predetermined time Td is reached. After reaching the time Td, the fuel injection stop flag Ffcut is set to zero. In step 43, basically, the predetermined time Td is set to be longer as the operating angle and the central angle at the previous stop deviate from the starting operating angle and the starting central angle. Here, since it is assumed that the ignition switch is turned on and the execution of the routine of FIG. 9 is started, the starter switch is turned on and cranking is started. However, if necessary, the determination of whether the starter switch is ON may be further added.

  As in this embodiment, at the time of restart after an abnormal stop, it is possible to start fuel injection at an appropriate time by setting the predetermined time Td according to the operating angle and center angle at the time of stop. It becomes.

  Next, a fourth embodiment of the control at the start will be described based on FIG. The routine shown in the flowchart of FIG. 10 is combined with the routine of FIG. 3 and FIG. 5 described above instead of the routine of FIG. 4 described above, and is repeatedly executed, for example, every 10 ms. First, in step 30, the state of the flag Fenst indicating the history of stoppage is determined. If the flag Fenst is 0, the routine proceeds to step 34, where the flag Ffcut for stopping fuel injection is set to 0. If the flag Fenst is 1, the routine proceeds to step 31, where it is detected whether the deviation between the actual operating angle and center angle at that time and the target starting operating angle and starting center angle has not been detected. It is determined whether it is. This is the same as step 22 in FIG. 6 described above, and a certain amount of time is required after the start of cranking to detect the amount of deviation. Until the detection of the deviation amount is completed, the process proceeds from step 31 to step 32, and the fuel injection stop flag Ffcut is set to 1. Thus, as described above, fuel injection is substantially prohibited by the routine of FIG.

  When the crankshaft rotates to some extent and a deviation amount is detected, the process proceeds from step 31 to step 32, where it is determined whether the sequentially detected deviation amount is larger than a predetermined reference deviation amount. If the deviation amount is larger than the reference deviation amount, the routine proceeds to step 32 where the fuel injection stop flag Ffcut is maintained at 1. When the deviation amount is equal to or less than the reference deviation amount, the routine proceeds to step 34 where the fuel injection stop flag Ffcut is set to zero.

  Therefore, if the operating angle or center angle deviates from the starting operating angle or starting center angle due to an abnormal stop, fuel injection is stopped and reaches the reference deviation amount until it becomes less than the reference deviation amount due to cranking. Since fuel injection is started at this stage, it is possible to reliably start the engine while preventing unburned fuel from being discharged.

  By the way, when the atmospheric temperature is high, ignition combustion is possible at a stage where the effective compression ratio is lower than when the atmospheric temperature is low. Therefore, the higher the atmospheric temperature, the predetermined time Td during which fuel injection is stopped. You may make it correct | amend so that it may become short. In addition, when the temperature of the internal combustion engine 1 such as the cooling water temperature or the lubricating oil temperature is low, the viscosity of the lubricating oil is high, and in particular, the operation until the central angle that is hydraulically controlled changes to the central angle at the start is slower. Become. Conversely, if the temperature of the internal combustion engine is high, such as during warm-up restart, the change in the central angle becomes faster and the combustion chamber temperature is higher, so that ignition combustion is possible at a stage where the effective compression ratio is lower. Therefore, the predetermined time Td for stopping the fuel injection may be corrected so as to be shorter as the engine temperature is higher.

  Similarly, in the case of the fourth embodiment shown in FIG. 10, the higher the atmospheric temperature or the engine temperature, the larger the value of the reference divergence amount in step 33 may be.

The system block diagram of the control apparatus of the internal combustion engine which concerns on this invention. The perspective view which shows the outline of a variable valve mechanism. The flowchart which shows the routine which memorize | stores and retains the history at the time of an engine stop. The flowchart which shows the routine for performing the fuel-injection stop at the time of starting. The flowchart which shows the routine of fuel injection amount control. The flowchart of the same routine as FIG. 4 in a 2nd Example. The characteristic view which shows the relationship between deviation amount and predetermined time Td. The flowchart of the routine similar to FIG. 3 in 3rd Example. The flowchart of the routine similar to FIG. 4 in 3rd Example. The flowchart of the routine similar to FIG. 4 in 4th Example.

Explanation of symbols

3 ... Intake valve 5 ... First variable valve mechanism 6 ... Second variable valve mechanism 10 ... Control unit

Claims (7)

A first variable valve mechanism that can continuously change the operating angle of the intake valve; and a second variable valve mechanism that can continuously change the central angle of the operating angle. In a control device for an internal combustion engine, which is configured to control the amount of intake air by changing the angle and the central angle, and includes a fuel injection device that injects fuel at a predetermined fuel injection timing,
When the rotation of the internal combustion engine is stopped, a history of whether or not the engine has stopped normally is stored, and when the internal combustion engine is started, the fuel injection stop period after the start of cranking is changed based on the history of the previous stop. A control device for an internal combustion engine characterized by the above.   2. The control apparatus for an internal combustion engine according to claim 1, wherein when the previous rotation stop of the internal combustion engine is an abnormal stop, the fuel injection stop period is lengthened.   When the rotation of the internal combustion engine stops, at least in the case of an abnormal stop, the operating angle and the central angle by the first and second variable valve mechanisms are stored and held as part of the history, and the fuel injection stop period is set as the history. 3. The control device for an internal combustion engine according to claim 1, wherein the control device is set based on an operating angle and a central angle of the engine.   When the previous rotation stop of the internal combustion engine was an abnormal stop, at the time of starting, the fuel injection is stopped until the detection of the actual operating angle and the central angle is completed, and the operating angle when the detection is completed and 3. The control apparatus for an internal combustion engine according to claim 1, wherein the fuel injection stop period is set based on an initial deviation amount between the center angle and each target value.   When the previous rotation stop of the internal combustion engine was an abnormal stop, the fuel injection is stopped at the start until the detection of the actual operating angle and the central angle is completed, and the detected operating angle and the central angle are respectively 3. The control device for an internal combustion engine according to claim 1, wherein the fuel injection is stopped until the amount of deviation from the target value falls within a predetermined allowable range.   The control apparatus for an internal combustion engine according to any one of claims 1 to 5, wherein the fuel injection stop period is corrected based on an atmospheric temperature or an internal combustion engine temperature. 6. The control apparatus for an internal combustion engine according to claim 5, wherein the allowable range of the deviation amount is corrected based on an atmospheric temperature or an internal combustion engine temperature.

Images