JP2006144724A - Air intake control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide torque response of characteristics as demanded irrespective of transient delay of a variable valve system. <P>SOLUTION: Static demand torque A1 and dynamic demand torque A2 are provided at a time of deceleration. Although second variable valve system target value C1 is calculated from the static demand torque, an actual value thereof delays as C2. A first variable valve system position materializing demand torque in actual value of the second variable valve system is calculated as a target value with using relating among the first, the second variable valve system positions, engine speed and torque materialized by that combination. There are two target values. The maximum torque position B3 of the first variable valve system calculated from a dynamic position C3 of the second variable valve system and static target value B1 of the first variable valve system 5 are compared to determine target value B4 of the first variable valve system with corresponding to large and small relation thereof. Consequently, torque response equivalent to the target dynamic demand torque is provided as indicated as D2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an intake air control device that controls an intake air amount sucked into a cylinder of an internal combustion engine, and more particularly to an internal combustion engine that achieves control of an intake air amount by variable control of valve lift characteristics of an intake valve. The present invention relates to an intake control device.

  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. On the other hand, 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. Similarly, it has been proposed to realize a so-called throttle-less configuration in which the intake system is not equipped with a throttle valve.

  Patent Document 1 discloses a variable valve mechanism that can be continuously variably controlled by a lift amount and an operating angle of an intake valve and a central angle of the lift previously proposed by the present applicant. According to this type of variable valve mechanism, as described above, it is possible to variably control the amount of air flowing into the cylinder without depending on the opening degree control of the throttle valve, particularly in a region where the load is small. In other words, so-called throttleless operation or operation with a sufficiently large opening of the throttle valve can be realized, and the pumping loss can be greatly reduced.

Furthermore, in Patent Document 2, correction is performed to improve torque response in the configuration in which the operating angle and the central angle of the intake valve are variably controlled independently of each other by the two variable valve mechanisms as described above. It is disclosed. That is, when the operating angle and the central angle of the intake valve are individually controlled by the two variable valve mechanisms, the two variable valve mechanisms have a certain amount of delay with respect to the target values at the time of a transient in which the operating state changes suddenly. Since it operates, the amount of intake air may deviate from the target value. In Patent Document 2 previously proposed by the present applicant, the response delay of one variable valve mechanism that changes the central angle is compensated by the other variable valve mechanism that changes the operating angle.
JP 2001-263105 A JP 2004-251274 A

  However, there are various transition modes. For example, when the response delay of one variable valve mechanism that changes the central angle is compensated by the other variable valve mechanism that changes the operating angle, the response under various conditions In consideration of the delay, the correction amount of the other variable valve mechanism must be adapted, the number of conforming elements increases, and it cannot be said that the maximum correction effect is obtained under all conditions.

  Hereinafter, an example thereof will be specifically described with reference to FIGS. FIG. 1 and the like are graphs showing the transition (change trajectory) of the maximum lift point (in other words, lift at the central angle) of the intake valve during transient travel together with the engine torque. In the figure, the horizontal axis indicates the central angle VTC, and the vertical axis indicates the operating angle (in other words, lift) VEL, and the maximum lift point is determined as a combination of both. This maximum lift point correlates with the volumetric efficiency of the engine and thus with the torque. Here, there are many combinations of the operating angle and the central angle for realizing the same torque, and therefore the torque is shown as a contour line as a contour line. In addition, an alternate long and short dash line V in the figure is a line in which the operating angle at which the torque is maximum at the same central angle is determined for each central angle, and these are successively connected. Hereinafter, this is defined as a “maximum torque line”. To do.

  For example, in a steady setting where the maximum lift point changes as shown by the line S in FIG. 1, the amount of depression of the accelerator is increased to perform a transient operation (acceleration) from the position indicated by the reference s1 to the position indicated by the reference s2. Consider the case. Here, in order to improve the torque responsiveness with respect to the delay of the central angle, assuming that the operating angle is increased from the steady set value as indicated by the line indicated by the symbol D, the symbol at the central angle indicated by the symbol v2 is given at a certain time. It passes through a point (reference numeral d1) that is the target operating angle indicated by v1. At this point d1, the torque indicated by the symbol T1 is realized. However, in the region above the maximum torque line V (region where the operating angle is large), the blowback increases, and the point (reference symbol) on the maximum torque line V at the same central angle. It becomes smaller than the torque (symbol T2) realized in d2). Therefore, a sufficient torque responsiveness improvement effect cannot be obtained, and conversely, the torque responsiveness may deteriorate.

  Next, in a steady setting where the maximum lift point changes as indicated by the line S in FIG. 2, transient operation (deceleration) from the position indicated by the symbol s <b> 1 to the position indicated by the symbol s <b> 2 by reducing the amount of depression of the accelerator is performed. Consider the case of going. Similarly, in order to improve the torque response, assuming that the operating angle is decreased from the steady set value as indicated by a line indicated by a symbol D, a point on the maximum torque line V from a point above the maximum torque line V (reference s1). Since the blow-back decreases when shifting to (symbol d1), the torque change may increase from the torque indicated by the symbol T1 to the torque indicated by the symbol T2, and the torque response may deteriorate. There is.

  In addition, in order to solve the above problem, the center angle target value (or the target value of one variable valve mechanism that changes the center angle) is calculated from a map prepared in advance for each torque (load) and rotation speed. The target value of the operating angle (or the target value of the other variable valve mechanism that changes the operating angle) is determined by using a load parameter that depends on the operating angle and the central angle. The present applicant has proposed a method of searching for an operating angle that realizes (load) and making it a target value. Here, in a steady setting in which the maximum lift point changes as indicated by a line indicated by reference numeral S in FIG. 3, the transition from the position indicated by reference numeral s1 to the position indicated by reference numeral s2 is performed by reducing the amount of depression of the accelerator. Considering that, at a certain time, the steady setting of the center angle and the working angle with respect to the required torque indicated by the reference symbol T becomes the position indicated by the reference symbols v20 and v10, respectively, and the actual setting with a delay from the central angle steady setting indicated by the reference symbol v20 Is the position indicated by the reference symbol v21. In this method, the operating angle that realizes the required torque at the actual center angle is calculated. At this time, the operating angle that realizes the required torque indicated by the symbol T at the central angle indicated by the symbol v21 is the maximum torque line V. In addition, there are two points, a point on the dotted line indicated by reference symbol D1 (reference symbol d1) and a point on the dotted line indicated by reference symbol D2 (reference symbol d2), and the target value during the transition of the operating angle is expressed by reference symbol v11. Either the position indicated by or the position indicated by reference sign v12 must be selected.

  Therefore, there was still room for improvement.

According to the present invention, as in claim 1, the first variable valve mechanism that can continuously change the operating angle of the intake valve of the internal combustion engine, and the second variable valve mechanism that can continuously change the central angle of the operating angle. In an intake air control apparatus for an internal combustion engine, comprising: a variable valve mechanism; and means for outputting a steady target value of the operating angle and the central angle so as to realize a target engine torque during steady state.
Means for detecting or estimating the actual value of the second variable valve mechanism;
When there are at least two positions of the first variable valve mechanism that can achieve the required torque under the actual value of the second variable valve mechanism, one of the target values of the first variable valve mechanism is selected. First variable valve mechanism target value setting means,
It is characterized by having.

  According to the first aspect of the present invention, the position (operating angle) of the first variable valve mechanism that can achieve the required torque at the actual value (actual center angle) of the second variable valve mechanism is two points. If one exists, one of the points is selected as the target value (target operating angle) of the first variable valve mechanism, so that the target of the first variable valve mechanism that reliably achieves the required torque without any hesitation. A value can be set, and a torque response close to a desired torque response can be realized.

  In a more specific aspect of the invention, the first variable valve mechanism target value setting means applies a maximum torque line corresponding to a line in which the operating angle at which the torque is maximum at the same central angle is determined for each central angle. Then, the target value of the first variable valve mechanism is calculated so that the magnitude relation between the current steady target value of the first variable valve mechanism and the target value of the first variable valve mechanism matches each other.

  Therefore, the magnitude relationship between the current steady-state target value and the transient target value with respect to the maximum torque line is made the same, so the torque response is smoothed by minimizing the number of times the transient target value crosses the maximum torque line. When the transition is over, the target value always converges to the steady setting.

  Furthermore, the invention of claim 3 further includes a transient determining means for determining whether the current operating state is a transient state, wherein the first variable valve mechanism target value setting means has a torque at the same central angle during the transition. Between the target value of the first variable valve mechanism before the start of the transient and the transient target value of the first variable valve mechanism with respect to a maximum torque line corresponding to a line in which the operating angle at which the angle is maximum is determined for each central angle The transient target value of the first variable valve mechanism is calculated so that the magnitude relationship matches each other.

  Therefore, since the magnitude relationship with the maximum torque line of the target value at the time of transition is determined at the position of the steady target value at the start of the transition, the maximum torque line is not crossed during the transition and the occurrence of a torque step is prevented. be able to.

  According to a fourth aspect of the present invention that further embodies the third aspect of the present invention, the current steady state target value of the first variable valve mechanism and the first variable valve mechanism when the current operating state is determined to be non-transient, When the magnitude relationship with respect to the maximum torque line differs from the target value of the first variable valve mechanism calculated by the one variable valve mechanism target value setting means, the first variable valve mechanism is maintained while maintaining equal torque. A stationary switching means for changing the target value of the mechanism and the target value of the second variable valve mechanism and switching the target value of the first variable valve mechanism to the current steady target value of the first variable valve mechanism; ing.

  Therefore, since the target value of both variable valve mechanisms is changed while maintaining equal torque, both variable valve mechanisms can always be returned to the steady target values desired to be realized in a steady state while preventing torque fluctuations.

  Further, in the invention of claim 5, the steady state switching means changes the target value of the second variable valve mechanism to the advanced angle side from the current steady state target value, and then returns to the steady target value. The target value of the variable valve mechanism is calculated using the actual value of the second variable valve mechanism and the load parameter depending on the position of the first variable valve mechanism and the position of the second variable valve mechanism.

  Therefore, at the time of switching, the target value of the first variable valve mechanism is calculated in accordance with the actual movement of the second variable valve mechanism, so that the equal torque line is traced while responding to the response delay of the second variable valve mechanism. Thus, torque fluctuation can be prevented at the time of switching.

  According to the present invention, when there are two positions of the second variable valve mechanism capable of realizing the torque required for the actual value of the second variable valve mechanism, one of the points is selected as the target value. As a result, a torque response close to a desired torque response can be realized.

  FIG. 4 is an explanatory diagram showing a system configuration of an intake control device 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 the valve of the intake valve 3 is operated. As a mechanism, the first variable valve mechanism (VEL) 5 capable of continuously expanding / reducing the lift / operation angle of the intake valve 3 and the center angle of the operation angle can be continuously delayed. A second variable valve mechanism (VTC) 6 is provided. The intake passage 7 is provided with a negative pressure control valve 2 whose opening degree is controlled by an actuator such as a motor. Here, the negative pressure control valve 2 is used to generate a slight negative pressure (for example, −50 mmHg) necessary for blowby gas processing or the like in the intake passage 7. The adjustment is performed by changing the lift characteristics of the intake valve 3 by the first and second variable valve mechanisms 5 and 6.

  More specifically, in the predetermined low load side region (first region), the opening degree of the negative pressure control valve 2 (target opening degree tBCV) is controlled so that the suction negative pressure is constant (for example, −50 mmHg). The And in the high load side region (second region) where the required load exceeds the maximum load that can be realized by changing the lift characteristic while generating this constant negative pressure, it is fixed to the lift characteristic at the point that becomes the limit, As the load, for example, the accelerator opening APO increases, the opening of the negative pressure control valve 2 further increases. That is, the intake air amount is adjusted by changing the lift characteristic of the intake valve 3 while maintaining a relatively weak intake negative pressure up to a certain load, and in the high load side region close to the fully open region, the intake negative pressure is adjusted. The amount of intake air is adjusted by reducing.

  The first and second variable valve mechanisms 5 and 6 and the negative pressure control valve 2 are controlled by the control unit 10.

  A fuel injection valve 8 is disposed in the intake passage 7, and an amount of fuel corresponding to the intake air amount adjusted by the intake valve 3 or the negative pressure control valve 2 as described above is supplied from the fuel injection valve 8. Be injected. 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 in the first region, and the negative pressure control valve 2 in the second region. Is controlled by adjusting the intake air amount.

  The control unit 10 includes an accelerator opening signal APO from an accelerator angle sensor 11 provided on an accelerator pedal operated by a driver, an engine speed signal Ne from an engine speed sensor 12, and an intake air amount sensor. 13 are received, and based on these signals, the fuel injection amount, ignition timing, first variable valve mechanism target value (target operating angle), second variable valve mechanism target value (target) Center angle) is calculated. The fuel injection valve 8 and the spark plug 9 are controlled so as to realize the required fuel injection amount and ignition timing, and a control signal for realizing the target operating angle and the target center angle is transmitted to the first variable valve mechanism. 5 and the actuator of the second variable valve mechanism 6 respectively. Here, the first variable valve mechanism 5 is driven by an actuator using an electric motor, and the second variable valve mechanism 6 is driven by a hydraulic actuator that uses engine lubricating oil pressure as a hydraulic source. The mechanical delay of the first variable valve mechanism 5 when the target value changes is relatively small, and the mechanical delay of the second variable valve mechanism 6 is relatively large. The first variable valve mechanism 5 and the second variable valve mechanism 6 have known mechanical configurations, and have, for example, the same configuration as the device described in Patent Document 1 described above. Therefore, the detailed description is abbreviate | omitted.

  FIG. 5 shows a first embodiment of the control of the present invention. In the above configuration, the first variable valve mechanism target value tVEL, the second variable valve mechanism target value tVTC, and the negative pressure control valve target opening tBCV are calculated. It is a schematic flowchart of the process to calculate. Here, engine torque (hereinafter referred to as torque) Te is used as a load parameter representing the load, but a parameter representing another load may be used. In the first embodiment, the position of the transient target value of the first variable valve mechanism 5 relative to the maximum torque line V is determined by the position of the current steady target value of the first variable valve mechanism relative to the maximum torque line V described above. First, a static demand torque tTes is calculated from the accelerator opening APO and the engine speed Ne (step 101), and the static demand torque tTes is appropriately modified to make a dynamic change. The required torque tTed is calculated (step 102). Next, the second variable valve mechanism target value tVTC is calculated from the static required torque tTes and the engine speed Ne (step 103), and the detected second variable valve mechanism actual value rVTC is read (step 104). The first variable valve mechanism target value tVEL is calculated from the target torque tTed (step 105). Further, the negative pressure control valve target opening degree tBCV is calculated from the dynamic required torque tTed (step 106). In this example, the dynamic required torque tTed is further calculated from the static required torque tTes calculated based on the accelerator opening APO and the engine speed Ne, and is used in the subsequent processing. The static demand torque tTes may be used as it is in the subsequent processing without being calculated.

  FIG. 6 is a flowchart showing the first variable valve mechanism target value calculation process in the first embodiment described above, and shows details of step 105. First, the steady target value tVELs of the first variable valve mechanism 5 and the dynamic position VTCd of the second variable valve mechanism 6 are calculated from the dynamic required torque tTed (step 111, step 112), and the second variable valve mechanism. The maximum torque position VELmax of the first variable valve mechanism 5 (the operating angle at which the torque is maximum at the same central angle) is calculated from the dynamic position VTCd of 6 (step 113). Next, the steady target value tVELs of the first variable valve mechanism 5 is compared with the maximum torque position VELmax of the first variable valve mechanism 5 (step 114). If tVELs> VELmax, the maximum torque line described above is obtained. A first variable valve mechanism target value tVEL equal to or greater than V is calculated (step 115). On the other hand, if tVELs ≦ VELmax in step 114, the first variable valve mechanism target value tVEL below the maximum torque line V is calculated (step 116).

  FIG. 7 is a functional block diagram showing the contents of the control of the first embodiment. Here, APO is the accelerator opening, and Ne is the engine speed. Based on these values, the static required torque calculator 101 calculates the static required torque tTes, and the dynamic required torque calculator 102 The dynamic required torque tTed is calculated. Based on the static required torque tTes and the engine speed Ne, the second variable valve mechanism target angle tVTC is retrieved from the second variable valve mechanism target angle calculation map mpVTC (105), and the dynamic required torque tTed and the engine Based on the rotational speed Ne, the negative pressure control valve target opening calculator 103 calculates the negative pressure control valve target opening tBCV. The first variable valve mechanism target value calculator 104 calculates the first variable valve mechanism target value tVEL based on the dynamic required torque tTed, the second variable valve mechanism actual value rVTC, and the engine speed Ne. .

  Here, the dynamic required torque calculation unit 102 calculates the dynamic required torque that is freely set by the designer. Therefore, a dynamic required torque equivalent to the static required torque may be obtained. Further, in the second variable valve mechanism target value calculation map mpVTC, the second variable valve mechanism position at which the fuel efficiency is optimal while satisfying the combustion stability in a steady state is set as the target value.

  FIG. 8 is a functional block diagram showing the contents of the first variable valve mechanism target value calculation unit 104 in the first embodiment. Here, tTed is the dynamic required torque, Ne is the engine speed, and rVTC is the second variable valve mechanism actual value, and based on these, the first variable valve mechanism position setting map equal to or greater than the maximum torque line V The first variable valve mechanism target value tVEL is retrieved from mpVELhigh (201) or the first variable valve mechanism position setting map mpVELlow (202) below the maximum torque line.

  Which of the two maps is used to search for the first variable valve mechanism target value is surrounded by a dotted line according to the current position of the first variable valve mechanism steady target value with respect to the maximum torque line V. This is determined by the first variable valve mechanism target value selection unit 203 shown in the part. First, based on the dynamic required torque tTed and the engine speed Ne, the first possible value from the first variable valve mechanism steady target value calculation map mpVELs (204) and the second variable valve mechanism position calculation map mpVTC (205), respectively. The variable valve mechanism steady target value tVELs and the second variable valve mechanism dynamic position VTCd are calculated. Next, based on the second variable valve mechanism dynamic position VTCd and the engine speed Ne, the maximum torque position VELmax of the first variable valve mechanism 5 from the first variable valve mechanism maximum torque position calculation map mpVELmax (206). If the first variable valve mechanism steady target value tVELs is greater than the maximum torque position VELmax of the first variable valve mechanism 5 by comparing the block 207, the first variable valve mechanism position that is greater than or equal to the maximum torque line is calculated. Search is made from the setting map mpVELhigh, and if not, selection is made via switching of the flag 208 so as to search from the first variable valve mechanism position setting map mpVELlow below the maximum torque line.

  Here, the first variable valve mechanism position setting map mpVELhigh (201) equal to or greater than the maximum torque line V includes torque Te, second variable valve mechanism position VTC, and engine speed Ne, based on previously measured data. The first variable valve mechanism position that is greater than or equal to the maximum torque line V is set, and the first variable valve mechanism position setting map mpVELlow (202) that is less than or equal to the maximum torque line V is based on previously measured data, A first variable valve mechanism position below the maximum torque line V with respect to torque Te, second variable valve mechanism position VTC and engine speed Ne is set. In this embodiment, the first variable valve mechanism target value is searched directly from these maps. However, the first variable valve mechanism position VEL, the second variable valve mechanism position VTC, and the engine speed Ne. The first variable valve mechanism target value not less than the maximum torque line V or the first variable valve mechanism target not greater than the maximum torque line V in accordance with the flag switching using the torque map mpTe in which the torque Te is set for A method of calculating a value may be used.

  FIG. 9 is a time chart showing the action at the time of transition (deceleration) according to the first embodiment. This is an effect when a transient running is performed to reduce the depression amount of the accelerator pedal, assuming that the rotation speed of the internal combustion engine is kept constant at a certain rotation speed, and (a) required torque, (b ) Shows changes in the first variable valve mechanism position, (c) second variable valve mechanism position, and (d) engine torque. Here, the responsiveness of the first variable valve mechanism 5 is much better than that of the second variable valve mechanism 6 and can be ignored. If the amount of depression of the accelerator pedal is reduced from time t1 to t3 during traveling, the static required torque tTes corresponding to the accelerator opening is obtained as shown by the line A1 in (a), and the dynamic required torque tTed is obtained. It is obtained as shown by the line A2 in FIG. This dynamic demand torque tTed matches the static demand torque at time t4. In the conventional example in which no correction is performed, the first variable valve mechanism target value tVEL and the second variable valve mechanism target value tVTC are calculated from steady target value calculation maps that are individually set. For example, the first variable valve mechanism target value tVEL is calculated from the dynamic required torque tTed as indicated by the line B1 in (b), and the second variable valve mechanism target value tVTC is the static required torque tTes. To (c) as indicated by the line C1. As a result, the actual value of the second variable valve mechanism 6 becomes as indicated by the line C2 in (c). Due to the response delay of the second variable valve mechanism 6, the torque response is (d). It is obtained as shown by the dotted line indicated by reference numeral D1.

  In the present embodiment, the target value of the first variable valve mechanism 5 is calculated according to the actual value of the second variable valve mechanism 6 instead of the preset steady target value. That is, the actual value of the second variable valve mechanism 6 is obtained by using the relationship between the first variable valve mechanism position, the second variable valve mechanism position, the engine speed, and the torque that can be realized for each combination thereof. The position of the first variable valve mechanism 5 that achieves the required torque is calculated as a target value. Here, in order to determine whether the first variable valve mechanism target value should be greater than or equal to the maximum torque line V or less than or equal to the maximum torque line V, it was calculated from the dynamic required torque tTed indicated by reference numeral A2 in (a). From the dynamic position VTCd of the second variable valve mechanism 6 indicated by reference numeral C3 in (c), the maximum torque position of the first variable valve mechanism 5 in the steady setting as indicated by the line indicated by reference numeral B3 in (b). VELmax is calculated and compared with the steady target value tVELs of the first variable valve mechanism 5 indicated by reference numeral B1 in (b). Then, either the first variable valve mechanism target value equal to or greater than the maximum torque line V or the first variable valve mechanism target value equal to or less than the maximum torque line V is selected so as to coincide with the magnitude relationship. As a result, the target value tVEL of the first variable valve mechanism 5 is obtained as shown by the line B4 in FIG. That is, at the time t2 when the maximum torque position VELmax of the first variable valve mechanism 5 with respect to the required torque and the steady target value tVELs of the first variable valve mechanism 5 intersect, the target value tVEL of the first variable valve mechanism 5 is The magnitude relationship with respect to the maximum torque position of the actual first variable valve mechanism 5 indicated by the symbol B2 in FIG. As a result, a torque response equivalent to the target dynamic required torque is obtained as indicated by the line D2 in (d), which is improved from the torque response of the conventional example.

  FIG. 10 is a graph showing the transition and torque of the maximum lift point according to the first embodiment. This represents the transition in the transient running of FIG. 9, and the required torque decreases from the torque indicated by the symbol T1 to the torque indicated by the symbol T2 in accordance with the accelerator opening, and the first variable valve mechanism 5 The target value of the second variable valve mechanism 6 changes from the point indicated by reference sign s1 on the steady setting indicated by reference sign S to the point indicated by reference sign s2. At a certain time, when the required torque is the torque indicated by symbol T3, the steady target values of the first variable valve mechanism 5 and the second variable valve mechanism 6 are at the positions indicated by symbols v10 and v20, respectively. At this time, the actual value of the second variable valve mechanism 6 is at the position indicated by the symbol v21 due to the response delay. In order to achieve the required torque at this position, the first variable valve mechanism 5 is at the position indicated by the symbol v11. It can be seen that it is sufficient to pass through a point (symbol d13) or a point (symbol d23) where the first variable valve mechanism 5 is at the position indicated by the symbol v12. In the present embodiment, since the steady setting indicated by reference sign s3 is above the maximum torque line V (that is, the operating angle is larger), the point indicated by reference sign d13 above the maximum torque line V is set at the time of transition. And Thus, by determining the setting at the time of transition so that the magnitude relationship with the maximum torque line V matches the steady setting indicated by the symbol S, the steady setting is set on the maximum torque line V as indicated by the symbol s4. The setting at the time of transition with respect to the required torque (reference T4) is switched from the point indicated by reference sign d14 to the point indicated by reference sign d24. As a result, the transient setting is on the line indicated by reference sign D1 from the point indicated by reference sign s1 to the point indicated by reference sign d12 until the required torque becomes the torque indicated by reference sign T4, and the required torque is the torque indicated by reference sign T4. After that time, a line indicated by a symbol D2 from a point indicated by a symbol d21 to a point indicated by a symbol s2 is obtained as a line indicated by a symbol D as a whole, and the required torque can always be realized. Further, when the transition is completed, it converges to the steady setting indicated by the symbol s2. Here, the time during which the required torque is the torque indicated by the symbol T4 corresponds to the time t2 in FIG.

  Next, a second embodiment of the control according to the present invention will be described with reference to FIGS.

  FIG. 11 is a schematic flowchart of processing for calculating the first variable valve mechanism target value, the second variable valve mechanism target value, and the negative pressure control valve target opening in the second embodiment. Here, as in the first embodiment, the torque Te is used as the load parameter representing the load, but a parameter representing another load may be used. Also, the dynamic required torque is calculated from the static required torque calculated from the accelerator opening and the engine speed, and is used in the subsequent processing. It may be used as it is in the processing. In the second embodiment, the position of the transient target value of the first variable valve mechanism 5 with respect to the maximum torque line V is determined by the position of the first variable valve mechanism target value at the start of transient with respect to the maximum torque line V. First, the static required torque tTes is calculated from the accelerator opening APO and the engine speed Ne (step 201), and the dynamic required torque tTed is calculated from the static required torque tTes (step 201). 202), the detected second variable valve mechanism actual value rVTC is read (step 104). Subsequently, a flag for calculating target values of the first variable valve mechanism 5 and the second variable valve mechanism 6 is calculated (step 204), and the second allowable value is determined from the static required torque tTes and the engine speed Ne. The variable valve mechanism target value tVTC is calculated (step 205), and the first variable valve mechanism target value tVEL is calculated from the dynamic required torque tTed (step 206). Further, the negative pressure control valve target opening tBCV is calculated from the dynamic required torque tTed (step 207).

  FIG. 12 is a flowchart showing the flag calculation process in the second embodiment and shows the details of step 204 described above. First, a transient determination flag flagTRANS for determining whether the current operating state is transient and a first variable valve mechanism steady target value range flag flagVELsHL are calculated (step 211, step 212), and the dynamic required torque tTed is calculated. 2 The variable valve mechanism most advanced angle position VTCadv is calculated (step 213). Next, a first variable valve mechanism target value selection flag flagVELHL and a steady switching flag flagCHANGE are calculated (step 214, step 215).

  FIG. 13 is a flowchart showing details of the first variable valve mechanism steady target value range flag calculation process in step 212. First, the first variable valve mechanism steady target value tVELs and the second variable valve mechanism dynamic position VTCd are calculated from the dynamic required torque tTed (steps 221 and 222), and the second variable valve mechanism dynamic position is calculated. The maximum torque position VELmax of the first variable valve mechanism 5 at VTCd is calculated (step 223). Next, the steady target value tVELs of the first variable valve mechanism 5 and the maximum torque position VELmax are compared (step 224). If tVELs> VELmax, flagVELsHL is set to 1 (step 225), and tVELs ≦ VELmax. Sets flagVELsHL to 0 (step 226).

  FIG. 14 is a flowchart showing details of the first variable valve mechanism target value selection flag calculation process in step 214. First, the transient determination flag flagTRANs is confirmed (step 231). If flagTRANS = 0, that is, if the current operating state is steady, the difference between the second variable valve mechanism maximum advance angle position VTCadv and the second variable valve mechanism actual value rVTC is compared with a predetermined value dVTC (step 232). ), | VTCadv−rVTC | ≦ dVTC, flagVELHL is set to the value of flagVELsHL described above (step 233). On the other hand, if flagTRANS = 1 in step 231, that is, if the current operating state is transient, and if | VTCAdv−rVTC |> dVTC in step 232, flagVELHL is not updated.

  FIG. 15 is a flowchart showing details of the steady switching flag calculation process in step 215. First, flagTRANs is confirmed (step 241). If flagTRANS = 0, that is, if the current operating state is steady, flagVELsHL and flagVELHL are compared (step 242). If flagVELsHL ≠ flagVELHL, flagCHANGE is set to 1 (step 243). On the other hand, if flagTRANS = 1 in step 241, that is, if the current operating state is transient and if flagVELsHL = flagVELHL in step 242, flagCHANGE is set to 0 (step 244).

  FIG. 16 is a flowchart showing a first variable valve mechanism target value calculation process in the second embodiment, and shows details of step 205 described above. First, the first variable valve mechanism target value selection flag flagVELHL is confirmed (step 251). If flagVELHL = 1, the first variable valve mechanism target value tVEL equal to or greater than the maximum torque line V is calculated (step 252). . On the other hand, if flagVELHL = 0 in step 251, the first variable valve mechanism target value tVEL below the maximum torque line V is calculated (step 253).

  FIG. 17 is a flowchart showing a second variable valve mechanism target value calculation process in the second embodiment, and shows details of step 206 described above. First, the steady switching flag flagCHANGE is confirmed (step 261). If flagCHANGE = 0, the second variable valve mechanism steady target value tVTCs is calculated from the static demand torque tTes (step 262), and the second variable motion is determined. The valve mechanism target value tVTC is set (step 263). On the other hand, when flagCHANGE = 1 in step 261, the second variable valve mechanism maximum advance angle position VTCadv is set to the second variable valve mechanism target value tVTC (step 264).

  FIG. 18 is a functional block diagram showing the contents of the control of the second embodiment. Here, APO is the accelerator opening, Ne is the engine speed, and based on these, the static required torque calculator 301 calculates the static required torque tTes, and the dynamic required torque calculator 302 The dynamic required torque tTed is calculated. Based on the dynamic required torque tTed, the second variable valve mechanism actual value rVTC, the engine speed Ne, and the second variable valve mechanism target value tVTCz one step before, in the flag calculation unit 303, the first variable valve A mechanism target value selection flag flagVELHL, a steady switching flag flagCHANGE and a second variable valve mechanism advance angle position VTCadv are calculated. Then, based on the dynamic required torque tTed, the second variable valve mechanism actual value rVTC, the first variable valve mechanism target value selection flag flagVELHL, and the engine speed Ne, the first variable valve mechanism target value calculation unit 304 The first variable valve mechanism target value tVEL is calculated, and based on the steady switching flag flagCHANGE, the second variable valve mechanism most advanced angle position VTCadv, the static required torque tTes, and the engine speed Ne, the second variable valve In mechanism target value calculation unit 305, second variable valve mechanism target value tVTC is calculated. Further, the negative pressure control valve target opening degree tBCV is calculated by the negative pressure control valve target opening degree calculation unit 306 based on the dynamic required torque tTed and the engine speed Ne.

  FIG. 19 is a functional block diagram showing the contents of the flag calculation unit 303 in the second embodiment. Here, tVTCz is the second variable valve mechanism target value one step before, tTed is the dynamic required torque, rVTC is the second variable valve mechanism actual value, and Ne is the engine speed. 2 Based on the variable valve mechanism target value tVTCz, the dynamic required torque tTed, and the second variable valve mechanism actual value rVTC, the transient determination flag calculation unit 401 calculates the transient determination flag flagTRANS, and the dynamic required torque tTed Based on the engine speed Ne, the first variable valve mechanism steady target value range flag calculation unit 402 calculates the first variable valve mechanism steady target value range flag flagVELsHL, and the second variable valve mechanism maximum advance angle position. The second variable valve mechanism most advanced angle position VTCadv is retrieved from the setting map mpVTCadv (403). Then, based on the transition determination flag flagTRANS, the second variable valve mechanism actual value rVTC, the first variable valve mechanism steady target value range flag flagVELsHL, and the second variable valve mechanism maximum advance angle position VTCadv, the first variable valve mechanism. The mechanism target value selection flag calculation unit 404 calculates the first variable valve mechanism target value selection flag flagVELHL, and the first variable valve mechanism target value selection flag flagVELHL and the first variable valve mechanism steady target value range flag flagVELsHL. Based on the transient determination flag flagTRANS, the steady switching flag calculation unit 405 calculates a steady switching flag flagCHANGE.

  FIG. 20 is a functional block diagram showing the contents of the first variable valve mechanism steady target value range flag calculation unit 402 described above. Here, tTed is the dynamic required torque, and Ne is the engine speed, and based on these, the first variable valve mechanism steady target value tVELs from the first variable valve mechanism steady target value calculation map mpVELs (501). And the second variable valve mechanism dynamic position VTCd is searched from the second variable valve mechanism steady target value calculation map mpVTCs (502). Then, based on the second variable valve mechanism dynamic position VTCd and the engine speed Ne, the maximum torque position VELmax of the first variable valve mechanism 5 is calculated from the first variable valve mechanism maximum torque position calculation map mpVELmax (503). If the first variable valve mechanism steady target value tVELs is larger than the maximum torque position VELmax of the first variable valve mechanism 5 by comparing the block 504 and the first variable valve mechanism steady target value range flag flagVELsHL is set to 1. Otherwise, the first variable valve mechanism steady target value range flag flagVELsHL is set to zero.

  FIG. 21 is a functional block diagram showing the contents of the first variable valve mechanism target value selection flag calculation unit 404 of FIG. Here, flagTRANS is a transient determination flag, VTCadv is the second most advanced valve position of the second variable valve mechanism, rVTC is the second variable valve mechanism actual value, dVTC is a predetermined value set in advance, flagTRANS = 0 and | VTCadv If −rVTC | ≦ dVTC, the first variable valve mechanism target value selection flag flagVELHL is set to the value of the first variable valve mechanism steady target value range flag flagVELsHL. Otherwise, the first variable valve mechanism target value is set. The value of the selection flag flagVELHL is not updated.

  FIG. 22 is a functional block diagram showing the contents of the steady switching flag calculation unit 405 of FIG. Here, flagTRANS is a transient determination flag, flagVELsHL is a first variable valve mechanism steady target value range flag, flagVELHL is a first variable valve mechanism target value selection flag, and if flagTRANS = 0 and flagVELsHL ≠ flagVELHL, The steady switching flag flagCHANGE is set to 1, otherwise the steady switching flag flagCHANGE is set to 0.

  FIG. 23 is a functional block diagram showing the contents of the first variable valve mechanism target value calculation unit 304 in the second embodiment of FIG. Here, flagVELHL is a first variable valve mechanism target value selection flag. If flagVELHL = 1, the maximum value is based on the dynamic target torque tTed, the second variable valve mechanism actual value rVTC, and the engine speed Ne. Search from the first variable valve mechanism position setting map mpVELhigh (601) above the torque line V. Otherwise, search from the first variable valve mechanism position setting map mpVELlow (602) below the maximum torque line V. On the other hand, it is selected through switching of the flag 603.

  Here, the first variable valve mechanism position setting map mpVELhigh (601) above the maximum torque line V includes torque Te, second variable valve mechanism position VTC, and engine speed Ne based on data measured in advance. The first variable valve mechanism position that is greater than or equal to the maximum torque line V is set, and the first variable valve mechanism position setting map mpVELlow (602) that is less than or equal to the maximum torque line V is based on previously measured data, A first variable valve mechanism position below the maximum torque line V with respect to torque Te, second variable valve mechanism position VTC and engine speed Ne is set. In the present embodiment, the first variable valve mechanism target value is searched directly from these maps, but with respect to the first variable valve mechanism position VEL, the second variable valve mechanism position VTC, and the engine speed Ne. Using the torque map mpTe in which the torque Te is set, the first variable valve mechanism target value equal to or greater than the maximum torque line V or the first variable valve mechanism target value equal to or less than the maximum torque line V is determined in accordance with the flag switching. A calculation method may be used.

  FIG. 24 is a functional block diagram showing the contents of the second variable valve mechanism target value calculator 305 in the second embodiment of FIG. Here, flagCHANGE is a steady switching flag. If flagCHANGE = 1, the second variable valve mechanism maximum advance angle position VTCadv is set to the second variable valve mechanism target value tVTC; otherwise, the static required torque Based on tTes and the engine speed Ne, the second variable valve mechanism steady target value tVTCs is retrieved from the second variable valve mechanism steady target value calculation map mpVTCs (701) to obtain the second variable valve mechanism target value tVTC. To do.

  FIG. 25 is a time chart showing the operation during transition (deceleration) according to the second embodiment. This is an effect when a transient running is performed to reduce the depression amount of the accelerator pedal, assuming that the rotation speed of the internal combustion engine is kept constant at a certain rotation speed, and (a) required torque, (b ) Each flag, (c) first variable valve mechanism position, (d) second variable valve mechanism position, (e) engine torque change. Here, the responsiveness of the first variable valve mechanism 5 is much better than that of the second variable valve mechanism 6 and can be ignored. If the amount of depression of the accelerator pedal is reduced from time t1 to t3 during traveling, the static required torque tTes corresponding to the accelerator opening is obtained as shown by the line A1 in (a), and the dynamic required torque tTed is obtained. It is obtained as shown by the line A2 in FIG. This dynamic demand torque tTed matches the static demand torque at time t4. In the conventional example in which no correction is performed, the first variable valve mechanism target value tVEL and the second variable valve mechanism target value tVTC are calculated from steady target value calculation maps that are individually set. For example, the first variable valve mechanism target value tVEL is calculated from the dynamic required torque tTed as shown by the line C1 in (c), and the second variable valve mechanism target value tVTC is the static required torque tTes. To (d) as indicated by the line indicated by the symbol D1. As a result, the actual value of the second variable valve mechanism 6 becomes as indicated by the line D2 in (d). Due to the response delay of the second variable valve mechanism 6, the torque response is (e). It is obtained as shown by the dotted line indicated by reference numeral E1.

  In the present embodiment, the target value of the first variable valve mechanism 5 is calculated according to the actual value of the second variable valve mechanism 6 instead of the preset steady target value. That is, the actual value of the second variable valve mechanism 6 is obtained by using the relationship between the first variable valve mechanism position, the second variable valve mechanism position, the engine speed, and the torque that can be realized for each combination thereof. The position of the first variable valve mechanism 5 that achieves the required torque is calculated as a target value. Here, the transition determination flag flagTRANS indicated by reference numeral B1 in (b), that is, during the period from time t1 to time t5 when the current operating state is transient, the transition determination flag flagTRANS indicated by reference numeral B1 in (b) and (b ) Is calculated based on the first variable valve mechanism steady target value range flag flagVELsHL indicated by symbol B2, and the first variable valve mechanism target value selection flag flagVELHL indicated by symbol B3 in FIG. The valve mechanism target value tVEL is a value larger than the maximum torque position of the actual first variable valve mechanism 5 indicated by the symbol C3 in (c), as indicated by the line indicated by the symbol C2 in (c). The transition determination flag flagTRANS indicated by reference numeral B1 in (b) is 0, that is, after the time t5 when the current operation state is steady, the actual torque position of the first variable valve mechanism 5 indicated by reference numeral C3 in (c) is reached. On the other hand, since the position of the first variable valve mechanism steady target value tVELs indicated by reference numeral C1 in (c) and the first variable valve mechanism target value tVEL indicated by reference numeral C2 in (c) are different, The steady switching flag flagCHANGE shown by reference numeral B4 becomes 1, and the second variable valve mechanism target value tVTC becomes the second variable valve mechanism maximum advance angle position VTCadv shown by reference numeral D3 in (d). At a time t6 when the difference between the second variable valve mechanism actual value indicated by reference numeral D4 in (d) and the second variable valve mechanism maximum advance angle position VTCadv indicated by reference numeral D3 in (d) is equal to or less than a predetermined value ( The first variable valve mechanism target value selection flag flagVELHL indicated by symbol B3 in b) becomes 0, and is indicated by symbol C2 in (c) in accordance with the actual value of the second variable valve mechanism indicated by symbol D4 in (d). As shown by the line, a first variable valve mechanism target value tVEL smaller than the maximum torque position of the actual first variable valve mechanism 5 indicated by reference C3 in (c) is calculated. As a result, as indicated by the line E2 in (e), a torque response equivalent to the target dynamic required torque is obtained, which is improved from the torque response of the conventional example. It can also be seen that the position of the first variable valve mechanism 5 converges to the steady target value while maintaining an equal torque at the steady state.

  FIG. 26 is a graph showing the transition and torque of the maximum lift point according to the second embodiment. This represents the transition in the transient running of FIG. 25, and the required torque decreases from the torque indicated by the symbol T1 to the torque indicated by the symbol T2 in accordance with the accelerator opening, and the first variable valve mechanism 5 An example in which the target value of the second variable valve mechanism 6 changes from the point indicated by reference sign s1 on the steady setting indicated by reference sign S to the point indicated by reference sign s2. Similar to the first embodiment, the position of the first variable valve mechanism 5 that realizes the required torque at the actual value of the second variable valve mechanism at the time of transition is in the region above the maximum torque line V, with reference numeral s1. The line indicated by reference sign D1 from the indicated point to the point indicated by reference sign d1 and the line indicated by reference sign D2 from the point indicated by reference sign d2 to the point indicated by reference sign s2 in the region below the maximum torque line V There is one. In the present embodiment, the first variable valve mechanism target value at the start of transition is a point indicated by reference sign s1, and is larger than the maximum torque line V. Therefore, the first variable valve mechanism target value at the time of transition is indicated by reference sign D1. It will move on the line indicated by. Like the transition shown in the present embodiment, when the transient setting is reversed with respect to the maximum torque line V at the end of the transition, the steady setting indicated by the reference sign s2 and the transient setting indicated by the reference sign d1 are indicated by the reference sign T2. In order to maintain the torque, the target values of the first variable valve mechanism 5 and the second variable valve mechanism 6 change on the dotted line indicated by the symbol D3 and return to the steady setting indicated by the symbol s2.

The characteristic view which shows transition of the maximum lift point at the time of transition (acceleration) in the case where the steady setting is a target value. The characteristic view which shows transition of the maximum lift point at the time of transition (deceleration) in the case where the steady setting is a target value. The characteristic view which shows transition of the maximum lift point at the time of the transition (deceleration) at the time of calculating the operating angle which implement | achieves a request torque in a real center angle. 1 is a system configuration diagram of an intake control device for an internal combustion engine according to the present invention. The flowchart which shows 1st Example of the control which concerns on this invention. The flowchart which shows the detail of the 1st variable valve mechanism target value calculation in this 1st Example. The functional block diagram of 1st Example. The block diagram which shows the detail of a 1st variable valve mechanism target value calculating part. The time chart at the time of the transition by 1st Example. The characteristic view which shows transition of the maximum lift point at the time of transition in 1st Example. The flowchart which shows 2nd Example of the control which concerns on this invention. The flowchart which shows the detail of the flag calculation. The flowchart which shows the detail of a 1st variable valve mechanism steady target value range flag calculation. The flowchart which shows the detail of 1st variable valve mechanism target value selection flag calculation. The flowchart which shows the detail of steady switching flag calculation. The flowchart which shows the detail of a 1st variable valve mechanism target value calculation. The flowchart which shows the detail of 2nd variable valve mechanism target value calculation. The functional block diagram of 2nd Example. The block diagram which shows the detail of a flag calculating part. The block diagram which shows the detail of a 1st variable valve mechanism steady target value range flag calculating part. The block diagram which shows the detail of a 1st variable valve mechanism target value selection flag calculating part. The block diagram which shows the detail of a regular switching flag calculating part. The block diagram which shows the detail of a 1st variable valve mechanism target value calculating part. The block diagram which shows the detail of a 2nd variable valve mechanism target value calculating part. The time chart at the time of the transition by 2nd Example. The characteristic view which shows transition of the maximum lift point at the time of transition in 2nd Example.

Explanation of symbols

2 ... Negative pressure control valve 5 ... First variable valve mechanism 6 ... Second variable valve mechanism 10 ... Control unit 11 ... Accelerator opening sensor

Claims (5)

A first variable valve mechanism capable of continuously changing the operating angle of the intake valve of the internal combustion engine;
A second variable valve mechanism capable of continuously changing the central angle of the operating angle;
Means for outputting a steady target value of the operating angle and the central angle so as to realize a target engine torque in a steady state;
In an internal combustion engine intake control device comprising:
Means for detecting or estimating the actual value of the second variable valve mechanism;
When there are at least two positions of the first variable valve mechanism that can achieve the required torque under the actual value of the second variable valve mechanism, one of the target values of the first variable valve mechanism is selected. First variable valve mechanism target value setting means,
An intake control device for an internal combustion engine, comprising: The first variable valve mechanism target value setting means includes:
The current steady-state target value of the first variable valve mechanism and the target value of the first variable valve mechanism with respect to a maximum torque line corresponding to a line in which the operating angle at which the torque becomes maximum at the same central angle is determined for each central angle. 2. The intake control device for an internal combustion engine according to claim 1, wherein a target value of the first variable valve mechanism is calculated so that a magnitude relationship between the first and second variable valve mechanisms coincides with each other. It further comprises a transient judging means for judging whether the current operating state is transient,
The first variable valve mechanism target value setting means includes:
The target value of the first variable valve mechanism before the start of the transition with respect to the maximum torque line corresponding to a line in which the operating angle at which the torque is maximum at the same central angle is determined for each central angle during the transition, and the first variable valve 2. The intake control device for an internal combustion engine according to claim 1, wherein the transient target value of the first variable valve mechanism is calculated so that a magnitude relationship with the transient target value of the mechanism matches each other.   When the current operation state is determined not to be transient, the current steady target value of the first variable valve mechanism and the first variable valve mechanism calculated by the first variable valve mechanism target value setting means at the end of the transition And the target value of the first variable valve mechanism and the target value of the second variable valve mechanism are changed while maintaining equal torque, and the target value of the second variable valve mechanism is changed. The intake control device for an internal combustion engine according to claim 3, further comprising a steady switching means for switching the target value of the one variable valve mechanism to the current steady target value of the first variable valve mechanism. The steady switching means is
The target value of the second variable valve mechanism is changed to an advanced angle side from the current steady target value and then returned to the steady target value, and the target value of the first variable valve mechanism is changed to that of the second variable valve mechanism. 5. The intake control device for an internal combustion engine according to claim 4, wherein the calculation is performed using an actual value and a load parameter depending on a position of the first variable valve mechanism and a position of the second variable valve mechanism. .

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