JP4110981B2 - Intake valve drive control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes an internal combustion engine having a first variable valve mechanism that changes an operating angle of an intake valve and a second variable valve mechanism that changes a central angle of the operating angle as a valve operating mechanism of the intake valve of the internal combustion engine. The present invention relates to an intake valve drive control device for an engine.
[0002]
[Prior art]
In order to improve the fuel consumption at low speed and low load of the internal combustion engine, to ensure stable operation, and to secure sufficient output by improving the intake charge efficiency at high speed and high load, the operating angle of the intake valve and its central angle are determined. Various intake valve drive control devices that can be changed according to operating conditions have been proposed.
[0003]
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 center angle of the lift, and according to the engine operating state, A technique is disclosed in which the operating angle and the central angle are appropriately variably controlled independently of each other to improve fuel consumption and output.
[0004]
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.
[0005]
[Patent Document 1]
JP-A-2001-263105 [0006]
[Problems to be solved by the invention]
However, in such a configuration in which the operating angle of the intake valve and the central angle thereof are variably controlled independently of each other according to the engine operating state, when the operating state suddenly changes, for example, the required load is in a low load range. In a transient state that changes from a high load range to a high load range at a relatively high speed, the two variable valve mechanisms operate with a certain amount of delay from the target value, and each operation delay can occur simultaneously. There is a possibility that the control response of the air amount is particularly deteriorated.
[0007]
[Means for Solving the Problems]
An intake valve drive control device for an internal combustion engine according to 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. In the first region where the intake air amount of the engine is relatively small, the operating angle is mainly changed to adjust the intake air amount, and in the second region where the intake air amount is relatively large. Mainly, the intake air amount is adjusted by changing the central angle.
[0008]
In the present invention, during the transient operation in which the target intake air amount of the internal combustion engine shifts from the first region to the second region, the second variable valve operating before the target intake air amount reaches the second region. Center angle change control by the mechanism is started.
[0009]
In other words, when the steady or intake air amount change is slow, the intake air amount is adjusted mainly by the operation of the first variable valve mechanism in the first region, and the central angle changes after shifting to the second region. In the transient operation where the intake air amount change is abrupt, the central angle starts to change before reaching the second region. Therefore, the actual change characteristic of the intake air amount approaches the change characteristic of the target intake air amount.
More specifically, the present invention relates to a target intake air amount basic value calculating means for calculating a target intake air amount basic value based on the rotational speed of the internal combustion engine and the accelerator opening, and to the target intake air amount basic value. Target intake air amount calculating means for performing a smoothing process to calculate the target intake air amount, and the target intake air amount abruptly shifts from the first region to the second region due to a change in the target intake air amount basic value. Transient detection means for detecting the predetermined transient operation to be performed, and central angle control of the second variable valve mechanism based on the target intake air amount other than the predetermined transient operation, and at the time of the predetermined transient operation And second variable valve mechanism control means for starting center angle control of the second variable valve mechanism based on the target intake air amount basic value.
[0010]
【The invention's effect】
According to the present invention, during the transient operation in which the target intake air amount of the internal combustion engine suddenly increases, the operation start timing of the second variable valve mechanism is advanced, so that the actual intake air amount change characteristic can be obtained. It is possible to approach the change characteristic of the amount, and the deterioration of the control response of the intake air amount during the transition can be suppressed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
[0012]
FIG. 1 is an explanatory diagram showing a system configuration of an intake valve drive control device for an internal combustion engine according to the present invention. The internal combustion engine 1 includes an intake valve 3 and an exhaust valve 4, and As the valve operating mechanism, a first variable valve operating mechanism (VEL) 5 capable of continuously expanding and reducing the lift / operating angle of the intake valve 3 and continuously delaying the central angle of the operating angle. A possible second variable valve mechanism (VTC) 6 is 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 performed by changing the 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 electronically controlled throttle valve 2 are controlled by the control unit 10, but basically, the combustion stability and fuel consumption of the internal combustion engine 1 are optimized. From a viewpoint, in a predetermined region where the intake air amount is relatively small (VEL region: first region), the central angle is fixed at a predetermined advance position, and the operation angle is adjusted to adjust the intake air amount. In a predetermined region where the intake air amount is relatively large (VTC region: second region), the intake angle is adjusted by fixing the operating angle to a predetermined large operating angle and changing the central angle.
[0013]
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 as described above is injected from the fuel injection valve 8. 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.
[0014]
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, an engine rotation speed signal Ne from an engine rotation speed sensor 12, and an intake air amount. The intake air amount signal from the sensor 13 is received, and based on these signals, the fuel injection amount, the ignition timing, the target operating angle, and the target central angle are 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. 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.
[0015]
Next, processing of a part according to the present invention in the arithmetic processing executed by the control unit 10 will be described.
[0016]
FIG. 2 is a flowchart showing a processing routine for calculating the target intake air amount. This processing routine is executed every predetermined time.
[0017]
In step 1, the accelerator opening APO and the engine speed Ne are read.
[0018]
In step 2, a basic value tVb of the target intake air amount is calculated based on the read accelerator opening APO and engine speed Ne. Specifically, from the control map in which the target intake air amount basic value tVb is stored in correspondence with the accelerator opening APO and the engine speed Ne, the accelerator opening APO and the engine speed Ne at that time are supported. Look up the value you want. The target intake air amount basic value tVb is a static target value of the intake air amount, and is determined on the premise of steady operation (a state in which the accelerator opening APO and the engine rotational speed Ne hardly change). .
[0019]
In step 3, the target intake air amount tV is calculated by subjecting the target intake air amount basic value tVb to a smoothing process. Specifically, first-order lag filtering is performed on the time-series data of the target intake air amount basic value tVb. By this annealing process, the intake air amount change characteristic in a general internal combustion engine in which the intake air amount is adjusted by a throttle valve is reproduced.
[0020]
In step 4, it is determined whether or not a predetermined transient condition is established based on the change in the target intake air amount basic value tVb. Specifically, the transient condition is satisfied when the current target intake air amount basic value tVb is in the first region (VEL region) and the target intake air amount basic value tVb is rising at a certain slope or more. Judge. In other words, when the operating angle is changed by the first variable valve mechanism 5 and the target intake air amount basic value tVb is expected to reach the second region (VTC region) immediately, it is transient. It is determined that the condition is met. When this predetermined transient condition is satisfied, there is a high possibility that the operation delay of the first variable valve mechanism 5 and the operation delay of the second variable valve mechanism 6 occur simultaneously. Once it is determined that the condition is satisfied, the transient determination is maintained until the actual intake air amount becomes near the target intake air amount tV.
[0021]
Next, FIG. 3 is a flowchart showing a processing routine for calculating the target operating angle. This processing routine is executed every predetermined time.
[0022]
In step 11, the target intake air amount tV and the engine rotational speed Ne calculated as described above are read.
[0023]
In step 12, a target operating angle tEVENT is calculated based on the target intake air amount tV and the engine speed Ne. Specifically, from the control map in which the target operating angle tEVENT is stored in correspondence with the target intake air amount tV and the engine rotational speed Ne, it corresponds to the target intake air amount tV and the engine rotational speed Ne at that time. Look up a value.
[0024]
When the target operating angle tEVENT is calculated in this way, a control signal for realizing this is transmitted to the actuator of the first variable valve mechanism 5.
[0025]
FIG. 4 is a flowchart showing a processing routine for calculating the target center angle. This processing routine is executed every predetermined time.
[0026]
In step 21, the target intake air amount basic value tVb and the target intake air amount tV calculated in the routine of FIG. 2 and the engine speed Ne are read.
[0027]
In step 22, based on the transient determination in step 4, it is determined whether or not the above-described transient condition is satisfied.
[0028]
If the transient condition is satisfied, the process proceeds to step 23, where the target center angle tCENTER is calculated based on the target intake air amount basic value tVb and the engine speed Ne. Specifically, from the control map in which the target center angle tCENTER is stored in correspondence with the target intake air amount basic value tVb and the engine rotational speed Ne, the target intake air amount basic value tVb and the engine rotational speed Ne at that time are stored. Look up the value corresponding to.
[0029]
On the other hand, when the predetermined transient condition is not satisfied, the routine proceeds to step 24, where the target center angle tCENTER is calculated based on the target intake air amount tV and the engine speed Ne subjected to the annealing process. Specifically, the same control map as that used in step 23 is used, and the value of the corresponding target center angle tCENTER is used by using the value of the target intake air amount tV instead of the target intake air amount basic value tVb. Look up.
[0030]
When the target operating angle tCENTER is calculated in this way, a control signal for realizing this is transmitted to the actuator of the second variable valve mechanism 6.
[0031]
FIG. 5 is a time chart showing the effect of the control of the present invention during a transition.
[0032]
As shown in FIG. 5A, when the accelerator opening APO rapidly increases, the target intake air amount basic value tVb changes in the same manner as the change in the accelerator opening APO, as shown in FIG. Since the transient response is too sensitive as it is, the target intake air amount tV is given by performing the annealing process by the first-order delay. As shown in the figure, in this example, the target intake air amount tV rapidly changes from the first region (VEL region) to the second region (VTC region), but based on the change of the target intake air amount basic value tVb. It is determined in advance that a predetermined transient condition is satisfied. While the target intake air amount tV is in the first region (VEL region), as shown in (c), the target operating angle tEVENT increases mainly, but due to the operation delay of the first variable valve mechanism 5, As shown in the figure, the actual operating angle changes later than this. On the other hand, the center angle by the second variable valve mechanism 6 is basically the target intake air amount tV in the second region (VTC region) as shown by the target center angle tCENTER (tV) as shown in (d). ) And is gradually controlled to the retard side based on the increase in the target intake air amount tV. However, as described above, in this case, the first variable motion is The operation delay of the valve mechanism 5 and the operation delay of the second variable valve mechanism 6 occur at the same time, and the responsiveness of the actual intake air amount change deteriorates.
[0033]
On the other hand, in the present invention, when it is determined as the predetermined transient condition, the target center angle tCENTER is given based on the target intake air amount basic value tVb as shown as the target center angle tCENTER (tVb). Therefore, the target central angle tCENTER changes to the retard side based on the increase of the target intake air amount basic value tVb from when the target intake air amount basic value tVb enters the second region (VTC region). As shown in the figure, the actual center angle changes with a target delay in the target center angle tCENTER (tVb). Thus, according to the present invention, when it is determined as a predetermined transition, the operation start time of the second variable valve mechanism 6, that is, the change start time of the central angle is changed from the time t1 to the time t2. It will be accelerated. Accordingly, the actual change characteristic of the intake air amount during the transition can be brought close to the change characteristic of the target intake air amount tV.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of an intake valve drive control device for an internal combustion engine according to the present invention.
FIG. 2 is a flowchart showing an intake air amount calculation routine.
FIG. 3 is a flowchart showing a target operating angle calculation routine.
FIG. 4 is a flowchart showing a routine for calculating a target center angle.
FIG. 5 is a time chart showing changes in operating angle, center angle, etc. during transition.
[Explanation of symbols]
2 ... Electronically controlled throttle valve 5 ... First variable valve mechanism 6 ... Second variable valve mechanism 10 ... Control unit 11 ... Accelerator opening sensor

Claims (1)

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 the relatively small first region, the operating angle is mainly changed to adjust the intake air amount, and in the second region where the intake air amount is relatively large, the central angle is mainly changed to adjust the intake air amount. In the intake valve drive control device for an internal combustion engine,
Target intake air amount basic value calculating means for calculating a target intake air amount basic value based on the rotational speed of the internal combustion engine and the accelerator opening;
Target intake air amount calculating means for calculating a target intake air amount by subjecting the target intake air amount basic value to smoothing;
Transient detecting means for detecting that the target intake air amount is a predetermined transient operation in which the target intake air amount suddenly shifts from the first region to the second region from a change in the target intake air amount basic value;
Except for the predetermined transient operation, center angle control of the second variable valve mechanism is performed based on the target intake air amount, and during the predetermined transient operation, the second variable operation is performed based on the target intake air amount basic value. Second variable valve mechanism control means for starting central angle control of the valve mechanism;
An intake valve drive control device for an internal combustion engine, comprising:

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