JP2014001645A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine, allowing control of an injection quantity with high accuracy even when a valve lift amount is relatively large.SOLUTION: The control device controls the injection quantity in the internal combustion engine including a lift amount variable mechanism for adjusting the valve lift amount VL of an intake valve. An actual phase which is an actual value in a phase of a pulse of an intake pressure Pin generated in an intake passage is compared with a reference phase which is preset as a reference value in the phase of the pulse of the intake pressure Pin, and the injection quantity TAU is corrected based on a delay angle amount ΔAPin which is a deviation quantity between the actual phase and the reference phase.

Description

  The present invention relates to a control device that controls a fuel injection amount of an internal combustion engine including a variable lift amount mechanism that adjusts a valve lift amount of an intake valve.

  Conventionally, control of the amount of fuel injected into the cylinder is performed based on the amount of in-cylinder intake air that is the amount of air sucked into the cylinder, and it is desired to improve the accuracy of the control. Further, in an internal combustion engine equipped with a variable lift amount mechanism that adjusts the valve lift amount of the intake valve based on the valve lift amount instruction value, the cylinder intake air amount changes according to the valve lift amount. It is necessary to consider the valve lift amount when controlling the injection amount.

  Here, deposits derived from unburned fuel or the like may adhere to the vicinity of the combustion chamber in the intake valve or intake passage. When the amount of deposit deposited in this way increases, the opening area of the intake valve decreases. Similarly, the opening area of the intake valve may be reduced due to deterioration over time of the lift amount variable mechanism. If the opening area of the intake valve is thus reduced, the in-cylinder intake air amount that is actually obtained with a predetermined valve lift amount instruction value may be less than the in-cylinder intake air amount that is actually obtained. That is, the valve lift amount (hereinafter referred to as the effective valve lift amount) corresponding to the actually obtained in-cylinder intake air amount may be smaller than the valve lift amount instruction value.

  In consideration of such a change in the effective valve lift amount, the control device for the internal combustion engine described in Patent Document 1 controls the fuel injection amount as follows. That is, for the estimated value of the in-cylinder intake air amount, the calculation based on the valve lift amount instruction value and the calculation based on the intake amount detected in the intake passage are performed together, and the ratio of the calculated estimated values is calculated. calculate. Then, the estimated value of the cylinder intake air amount based on the valve lift amount instruction value is corrected based on the ratio, and the fuel injection amount is controlled based on the corrected estimated value of the cylinder intake air amount. ing.

JP 2005-54611 A

  By the way, when the valve lift is relatively small, the internal pressure difference between the intake passage and the combustion chamber becomes large, and the intake air flows into the combustion chamber at a speed close to the sonic speed. The in-cylinder intake air amount in such a state is almost unaffected by fluctuations in the intake passage and the internal pressure of the combustion chamber, and is determined by an increase or decrease in the valve lift amount. Based on such knowledge, the control apparatus for an internal combustion engine described in Patent Document 1 calculates the in-cylinder intake air amount estimated based on the valve lift amount instruction value on the condition that the valve lift amount instruction value is relatively small. This is used to control the fuel injection amount.

  However, in order to control the fuel injection amount with high accuracy, it is desirable to control the fuel injection amount in consideration of the valve lift amount even when the valve lift amount is relatively large. The control device for the internal combustion engine of the present invention leaves room for improvement in this respect.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control device for an internal combustion engine that can control the fuel injection amount with high accuracy even when the valve lift amount is relatively large. There is to do.

In the following, means for achieving the above object and its effects are described.
In the control device for controlling the fuel injection amount of the internal combustion engine having the variable lift amount mechanism for adjusting the valve lift amount of the intake valve, the invention according to claim 1 is an actual value of the phase of the intake pressure pulsation generated in the intake passage. The gist is to compare a certain actual phase with a reference phase set in advance as a reference value for the phase of the intake pressure pulsation, and to correct the fuel injection amount based on the amount of deviation between the actual phase and the reference phase. And

  If the effective valve lift amount changes due to deposit adhesion or aging deterioration of the lift amount variable mechanism, the timing at which the predetermined intake pressure flows into the cylinder from the intake passage as the intake valve opens will change the effective valve lift amount. It will deviate from the timing when it does not occur. As a result, the phase of the intake pressure pulsation generated in the intake passage differs between when the effective valve lift amount changes and when it does not change.

  According to the above configuration, with respect to the phase of the intake pressure pulsation generated in the intake passage, whether the effective valve lift amount has changed by comparing the actual phase that is the actual value with the reference phase that is preset as the reference value. It can be determined whether or not. The phase of the intake pressure pulsation in the intake passage is determined according to the shape of the intake passage and the valve lift amount. For this reason, depending on the above configuration, the effective valve can be adjusted regardless of the amount of valve lift by correcting the fuel injection amount based on the amount of deviation between the actual phase of the intake pressure pulsation and the reference phase. Changes in the lift amount can be reflected in the correction of the fuel injection amount. Therefore, according to the above configuration, the fuel injection amount can be controlled with high accuracy even when the valve lift amount is relatively large.

  Specifically, as described in claim 2, the variable lift amount mechanism adjusts the valve lift amount based on a valve lift amount instruction value, and the fuel injection amount is controlled based on the valve lift amount instruction value. When correcting the fuel injection amount, the valve lift amount instruction value is corrected based on the deviation amount to calculate the effective valve lift amount, and the effective valve lift amount is used instead of the valve lift amount instruction value. A configuration in which the fuel injection amount is corrected based on the above can be employed.

  According to a third aspect of the present invention, in the control device for an internal combustion engine according to the first or second aspect, the intake passage includes a pressure sensor that detects an intake pressure in the intake passage, and the detected value of the pressure sensor The gist is to calculate the actual phase based on this.

  According to a fourth aspect of the present invention, in the control device for an internal combustion engine according to the first or second aspect, the control device includes a pressure sensor that detects a pressure in a cylinder of the internal combustion engine. The gist is to calculate the actual phase.

  The actual phase of the intake pressure pulsation generated in the intake passage may be calculated based on the detection value of the pressure sensor that detects the intake pressure in the intake passage as described in claim 3. As described above, it may be calculated based on the detection value of a pressure sensor that detects the pressure in the cylinder. Note that, in the intake stroke in which the intake valve opens, the intake pressure in the intake passage and the pressure in the cylinder have substantially the same value. For this reason, even if the detection value of any of the pressure sensors described above is used, there is no difference in the accuracy of calculation of the actual phase of the intake pressure pulsation that occurs in the intake passage.

The schematic diagram which shows typically the structure of the internal combustion engine to which this is applied about one Embodiment of the control apparatus which concerns on this invention. The graph which shows the change aspect of the valve lift amount of an intake valve based on the action | operation of a lift amount variable mechanism. The graph which shows an example of the relationship between the time-dependent change of the effective valve lift amount, and the time-dependent change regarding the intake pressure pulsation based on the operation of the lift amount variable mechanism. The block diagram which shows typically the control performed with the control apparatus in the embodiment. The graph which shows the relationship between the retardation amount of the real phase with respect to the reference | standard phase and correction amount in the embodiment. The flowchart which shows the process sequence of the fuel injection amount calculation process in the embodiment. The graph which shows the relationship between intake pressure and in-cylinder pressure.

Hereinafter, an embodiment embodying the present invention will be described.
Here, first, the configuration of the control device for an internal combustion engine of the present embodiment will be described with reference to FIG. Note that the internal combustion engine 10 to which the control device of this embodiment is applied includes four cylinders # 1 to # 4.

  As shown in FIG. 1, a throttle valve 22 is provided in the intake passage 20 of the internal combustion engine 10 and upstream of the surge tank 21. The opening degree of the throttle valve 22 (throttle opening degree TA) is adjusted through drive control of the throttle motor 24, and thereby the amount of air taken into the combustion chamber 12 from the intake passage 20 is adjusted.

  The intake passage 20 is branched downstream of the surge tank 21 into four passages that respectively communicate with the cylinders # 1 to # 4. Each of the branched passages is provided with an injector 26 for injecting fuel into the intake air flowing through the passage.

  In the combustion chamber 12 of the internal combustion engine 10, ignition by the spark plug 30 is performed on the air-fuel mixture composed of intake air and injected fuel. By this ignition operation, the air-fuel mixture burns, the piston 14 reciprocates, and the crankshaft 16 rotates. The air-fuel mixture after combustion is sent out from the combustion chamber 12 to the exhaust passage 32 as exhaust.

  In the internal combustion engine 10, the intake camshaft 40 rotates in response to the rotation of the crankshaft 16, and the intake valve 28 opens and closes as the intake camshaft 40 rotates. Then, in accordance with the opening / closing operation of the intake valve 28, the intake passage 20 and the combustion chamber 12 are communicated and blocked. Further, a variable lift amount mechanism 42 between the intake valve 28 and the intake camshaft 40 that changes the valve lift amount VL of the intake valve 28 based on a valve lift amount instruction value VLo set according to engine operating conditions. Is provided. The lift amount variable mechanism 42 operates through drive control of an actuator 44 such as an electric motor. The valve lift amount VL of the intake valve 28 is changed by the operation of the lift amount variable mechanism 42, whereby the valve opening period of the intake valves 28 of the cylinders # 1 to # 4 is changed.

  On the other hand, the control device of the present embodiment is provided with various sensors for detecting the operating state of the internal combustion engine 10. Examples of such sensors include a crank sensor 50 for detecting the rotational phase (crank angle CA) and rotational speed (engine rotational speed NE) of the crankshaft 16, and an accelerator sensor 53 for detecting the depression amount AC of the accelerator pedal 52. There is a throttle sensor 54 for detecting the throttle opening degree TA. Further, the intake passage 20 is provided with a pressure sensor 56 for detecting the pressure of the intake air (intake pressure Pin) therein. In the internal combustion engine 10, pressure sensors 56 are individually provided in a portion of the intake passage 20 downstream of the surge tank 21 branched for each of the cylinders # 1 to # 4.

  Detection signals of the various sensors are taken into the electronic control device 60. The electronic control unit 60 performs various calculations related to the control of the internal combustion engine 10 based on the acquired detection signal. The electronic control unit 60 includes an arithmetic unit, a memory for storing various control programs, arithmetic maps, data calculated when the control is executed, and the like. Then, based on the result of calculation performed by the electronic control unit 60, drive control of the throttle motor 24 (throttle control), drive control of the injector 26 (fuel injection control), drive control of the actuator 44 (lift amount change control), etc. Various controls are executed.

  In the internal combustion engine 10, the cylinder intake air amount MC, which is the intake amount sucked into the cylinders # 1 to # 4, is adjusted as follows through throttle control and lift amount change control. That is, the electronic control unit 60 calculates the target value of the cylinder intake air amount MC based on the depression amount AC of the accelerator pedal 52 and the engine speed NE. The electronic control unit 60 adjusts the in-cylinder intake air amount MC by executing throttle control and lift amount change control based on the target value.

  In the present embodiment, the fuel injection amount TAU is adjusted according to the in-cylinder intake air amount MC adjusted through throttle control and lift amount change control. Specifically, the electronic control unit 60 calculates the fuel amount at which the air-fuel ratio of the air-fuel mixture becomes the stoichiometric air-fuel ratio as the target value of the fuel injection amount TAU with respect to the in-cylinder intake air amount MC. Then, the electronic control unit 60 executes fuel injection control so that the fuel injection amount TAU is set to the target value.

  As described above, in the present embodiment, the in-cylinder intake air amount MC is adjusted by the valve lift amount instruction value VLo of the intake valve 28. Then, the target value of the fuel injection amount TAU is determined so as to match the adjusted intake air amount MC.

  However, when the internal combustion engine 10 is used for a long period of time, deposits may adhere to the intake valve 28 and its periphery, and the opening area of the intake valve 28 secured by the same amount of lift may decrease. In addition, the valve lift amount of the intake valve 28 that is actually secured may be smaller than the valve lift amount instruction value VLo due to deterioration over time of the lift amount variable mechanism 42. As a result, the correlation between the actually secured in-cylinder intake air amount MC and the valve lift amount instruction value VLo changes. That is, the valve lift amount (hereinafter referred to as the effective valve lift amount VL ′) corresponding to the actually secured in-cylinder intake air amount MC becomes smaller than the valve lift amount instruction value VLo. Note that the effective valve lift amount VL ′ indicates the value of the valve lift amount instruction value VLo in which the current in-cylinder intake air amount MC is ensured in a state where the relative relationship does not change with time.

  When the effective valve lift amount VL ′ is smaller than the valve lift amount instruction value VLo, the actually secured in-cylinder intake air amount MC is less than the amount assumed from the value of the valve lift amount instruction value VLo at that time. Become. That is, the in-cylinder intake air amount MC calculated by the electronic control unit 60 based on the valve lift amount instruction value VLo is larger than the actual amount. As a result, the target value of the fuel injection amount TAU cannot be set properly. Therefore, when the fuel injection amount TAU is controlled, it is necessary to consider such a change with time of the effective valve lift amount VL ′.

  When the valve lift amount instruction value VLo is relatively small, the change with time of the effective valve lift amount VL ′ can be confirmed from the change rate of the intake air amount. At this time, since the intake air amount is small in the first place, the reduction amount of the intake air amount due to the reduction in the effective valve lift amount VL ′ is relatively large. Therefore, the change with time of the effective valve lift amount VL ′ can be suitably confirmed from the change rate of the current intake air amount with respect to the intake air amount when there is no change with time of the effective valve lift amount VL ′.

  On the other hand, when the valve lift amount instruction value VLo is large, the intake air amount is large in the first place. Therefore, the amount of decrease in the intake air amount due to the decrease in the effective valve lift amount VL ′ is relatively small. Therefore, the change in the intake air amount due to the change over time in the effective valve lift amount VL ′ at this time is relatively small with respect to the change in the intake air amount due to other factors, and the influence thereof is the rate of change in the intake air amount. Will not appear clearly.

  On the other hand, when the effective valve lift amount VL ′ decreases due to a change with time, the valve opening timing of the intake valve 28 is delayed from the original. In the example of FIG. 2, the effective valve lift amount VL ′ of cylinder # 2 and cylinder # 4 is in a state of being reduced from the original, and in these cylinders # 2 and # 4, the opening timing of intake valve 28 is It is late than originally intended. As a result, in these cylinders # 2 and # 4, the timing at which the intake air starts to flow into the cylinders is delayed from the original.

  On the other hand, in the intake passage 20, pulsation of the intake pressure Pin is generated starting from a pressure drop accompanying opening of the intake valve 28. When the opening of the intake valve 28 is delayed, the phase of the intake pressure pulsation is also delayed. Therefore, when the effective valve lift amount VL ′ of the cylinder # 2 and the cylinder # 4 is decreased, the phase of the intake pulsation in the intake stroke of the cylinders # 2 and # 4 is delayed as shown in FIG. .

  The phase delay of the intake pressure pulsation due to the decrease in the effective valve lift amount VL ′ occurs regardless of the magnitude of the valve lift amount instruction value VLo. Therefore, in the present embodiment, by correcting the fuel injection amount TAU based on the phase of the intake pressure pulsation generated in the intake passage, the influence of the change over time in the effective valve lift amount VL ′ is reflected in the fuel injection amount control. I have to.

  FIG. 4 shows a control block diagram of control related to the calculation of the fuel injection amount TAU in the present embodiment. As shown in the figure, the calculation of the fuel injection amount TAU is performed through each of a phase difference detection process 62, a valve lift amount correction process 64, a cylinder intake air amount calculation process 66, and a fuel injection amount calculation process 68. .

  In the phase difference detection process 62, the actual phase, which is the actual value of the intake pressure pulsation phase, is compared with a reference phase set in advance as a reference value of the same phase, and the deviation between the actual phase and the reference phase is obtained. It is done. The amount of divergence includes the waveform of the detected value of the intake pressure Pin of the pressure sensor 56 in the section of 180 ° CA from the start to the end of the intake stroke, and the reference stored in the nonvolatile memory 63 provided in the electronic control unit 60. It is obtained by comparing with the waveform. In the memory 63, the waveform of the intake pulsation of each cylinder # 1 to # 4 in each operation state of the internal combustion engine 10 in a state where there is no change over time of the effective valve lift amount VL ′, which is obtained in advance through experiments or the like, It is stored as a waveform. Then, the reference waveform corresponding to the current operating state of the corresponding cylinder is read and compared with the actual waveform, thereby obtaining the retardation amount ΔAPin of the actual phase with respect to the reference phase of the intake pressure pulsation. The retard amount ΔAPin calculated here is transferred to the valve lift amount correction process 64 together with the cylinder number n of the corresponding cylinder.

  In the valve lift amount correction process 64, the current effective valve lift amount VL ′ (n) of the corresponding cylinder is obtained based on the retard amount ΔAPin and the cylinder number n delivered from the valve lift amount correction process 64. . The effective valve lift amount VL ′ (n) is a correction amount β obtained according to the retardation amount ΔAPin from the valve lift amount instruction value VLo (n) of the cylinder #n corresponding to the delivered cylinder number n. Calculated by subtraction. The correction amount β is obtained using a correction amount calculation map M1 provided for each cylinder. In these maps M1, for example, as shown in FIG. 5, the relationship between the retard amount ΔAPin of the intake pressure pulsation phase and the decrease amount of the effective valve lift amount (correction amount β) in each cylinder is stored. . The relationship between the amount of retardation ΔAPin of the intake pressure pulsation phase and the amount of decrease in the effective valve lift amount (correction amount β) in the map M1 is obtained in advance through experiments or the like.

  In the cylinder intake air amount calculation processing 66, the cylinder intake air amount MC (n) of the corresponding cylinder is calculated based on the effective valve lift amount VL ′ (n) obtained in the valve lift amount correction processing 64. . The in-cylinder intake air amount MC (n) is calculated using a map M2 for calculating the in-cylinder intake air amount provided for each cylinder. The calculation map M2 includes an effective valve lift amount VL ′ (n), an engine speed NE, an engine load KL, and an in-cylinder intake air amount MC (n) obtained in advance through experiments or the like. ) Is stored. The engine load KL is calculated based on the throttle opening degree TA, the depression amount AC of the accelerator pedal 52, and the like.

  In the fuel injection amount calculation processing 68, the fuel injection amount TAU (n) is calculated based on the cylinder intake air amount MC (n) obtained in the cylinder intake air amount calculation processing 66. The fuel injection amount TAU is calculated so that the ratio to the in-cylinder intake air amount MC (n) becomes the stoichiometric air-fuel ratio.

  As described above, in the present embodiment, the valve lift amount instruction value VLo (n) is corrected based on the deviation amount (retard amount ΔAPi) between the actual phase and the reference phase, and the corrected valve lift amount instruction In-cylinder intake air amount MC (n) is calculated using value VLo (n) (effective valve lift amount VL ′ (n)). Then, the fuel injection amount TAU (n) is calculated based on the calculated in-cylinder intake air amount MC (n). In other words, in the present embodiment, the fuel injection amount is corrected based on the amount of deviation between the actual phase of the intake pressure pulsation and the reference phase when viewed broadly.

  Each process as described above is performed by the electronic control unit 60 performing the fuel injection amount calculation process shown in FIG. This fuel injection amount calculation process is repeatedly executed at predetermined intervals during the operation of the internal combustion engine 10.

  As shown in FIG. 6, when the fuel injection amount calculation process is started, first, among the cylinders # 1 to # 4, the number n of the cylinder in which the intake valve 28 is open is determined (step S120). . Then, the detected value of the intake pressure Pin of the pressure sensor 56 corresponding to the cylinder in which the intake valve 28 is determined to be in the open state (hereinafter referred to as cylinder #n) is read (step S130).

  When the intake pressure Pin is read, the actual phase of the intake pressure pulsation is obtained from the read intake pressure Pin, and the retardation amount ΔAPin with respect to the reference phase of the obtained actual phase is calculated. Then, it is determined whether or not the retardation amount ΔAPin is equal to or greater than a predetermined amount k (step S140). Here, the predetermined amount k is set to an amount of change in the intake pressure pulsation phase that can be determined that a decrease in the effective valve lift amount VL ′ (n) due to a change with time has occurred. It is required by experiments.

  If it is determined that the retardation amount ΔAPin is equal to or greater than the predetermined amount k (step S140: YES), a correction amount β is calculated based on the retardation amount ΔAPin (step S150). Then, the effective valve lift amount VL ′ (n) is calculated by correcting the valve lift amount instruction value VLo (n) based on the correction amount β (step S160).

  On the other hand, if the retardation amount ΔAPin is less than the predetermined amount k (step S140: NO), the value of the valve lift amount instruction value VLo (n) is calculated as it is as the value of the effective valve lift amount VL ′ (n) ( Step S170).

  Thereafter, the in-cylinder intake air amount MC (n) is calculated based on the effective valve lift amount VL ′ (n) thus calculated (S180). Then, after the fuel injection amount TAU is calculated based on the calculated in-cylinder intake air amount MC (n) (S190), the process of this routine is terminated.

  In the present embodiment described above, the above calculation is performed even when the air-fuel ratio varies between the cylinders # 1 to 4 depending on whether or not the deviation of the actual phase of the intake pressure pulsation from the reference phase occurs. By executing the fuel injection control with the fuel injection amount TAU (n) as a target value, the degree of variation in the air-fuel ratio between the cylinders # 1 to # 4 is suppressed. For example, among cylinders # 1 to # 4, in cylinder # 2 and cylinder # 4, a state occurs in which the actual phase of the intake pressure pulsation is retarded with a retardation amount ΔAPin of a predetermined amount k or more with respect to the reference phase. If you have:

  That is, in cylinder # 2 and cylinder # 4, when the actually obtained in-cylinder intake air amount MC becomes smaller than the originally obtained amount due to deposits or the like, a substantial valve lift amount (effective valve lift amount VL ' ) Becomes smaller than the valve lift amount instruction value VLo. At this time, if the fuel injection amount TAU is set in accordance with the in-cylinder intake air amount MC assumed from the valve lift amount instruction value VLo at that time, an excessive amount of fuel is larger than the actual in-cylinder intake air amount MC. The air-fuel ratio of the air-fuel mixture injected and burned in the cylinders # 2 and 4 becomes rich.

  Note that the phase of the intake pressure pulsation in the intake strokes of the cylinders # 2 and # 4 is delayed due to the decrease in the effective valve lift amount VL 'at this time. In this embodiment, the fuel injection amount TAU is corrected to decrease in accordance with such a phase delay. Therefore, the degree of enrichment of the air-fuel ratio in the cylinders # 2 and # 4 is reduced, and as a result, the degree of variation in the air-fuel ratio between the cylinders # 1 to # 4 is suppressed.

As described above, according to the present embodiment, the following effects can be obtained.
(1) In the present embodiment, the actual phase that is the actual value of the phase of the intake pressure pulsation generated in the intake passage 20 is compared with the reference phase that is preset as the reference value of the phase of the intake pressure pulsation, and these phases are compared. The fuel injection amount TAU is corrected based on the deviation amount. Therefore, regardless of the magnitude of the valve lift amount VL, the change in the effective valve lift amount VL ′ can be reflected in the correction of the fuel injection amount TAU. Therefore, according to the present embodiment, the fuel injection amount TAU can be controlled with high accuracy even when the valve lift amount VL is relatively large.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the above embodiment, the fuel injection amount TAU is corrected based on the retardation amount ΔAPin of the actual phase with respect to the reference phase of the intake pressure pulsation. Depending on the configuration of the lift amount variable mechanism, the change over time in the effective valve lift amount VL ′ may progress in a direction to advance the actual phase of the intake pressure pulsation with respect to the reference phase. In such a case, the same effect as the above (1) can be obtained by correcting the fuel injection amount TAU based on the advance amount of the actual phase with respect to the reference phase of the intake pressure pulsation.

  In the above embodiment, the actual phase of the intake pressure pulsation is obtained from the detection result of the pressure in the intake passage 20 (intake pressure), but from the detection result of the internal pressure (in-cylinder pressure) of each cylinder # 1 to # 4. It is also possible to obtain the actual phase of the intake pressure pulsation. As shown in FIG. 7, in the intake stroke in which the intake valve 28 opens, the intake pressure Pin and the in-cylinder pressure have substantially the same value. Therefore, a pressure sensor for detecting the in-cylinder pressure can be installed in each cylinder, and the detection result can be used for the actual phase of the intake pressure pulsation.

  In the above embodiment, the pressure sensor 56 is provided for each of the cylinders # 1 to # 4, and the intake pressure pulsation accompanying the intake of each cylinder is individually detected. One pressure sensor may detect intake pressure pulsation.

  In the above embodiment, the detection value of the pressure sensor 56 is adopted as the intake pressure Pin used for calculating the actual phase of the intake pressure pulsation, but a physical model that simulates the physical behavior of the intake system is used. The future intake pressure predicted from the detected value of the intake pressure up to that point and the transition of the engine operating state may be used. If the actual phase of the intake pressure pulsation is calculated using the predicted value of the future intake pressure, the fuel injection amount TAU before the phase shift of the intake pressure pulsation due to the change over time of the effective valve lift amount VL ′ actually occurs. Therefore, the fuel injection amount TAU can be controlled with higher accuracy.

  In the above-described embodiment, the amount of deviation between the reference phase and the actual phase in each cylinder # 1 to # 4 is obtained by comparing the actual waveform of the intake pressure pulsation with the reference waveform, but in other calculation modes It is also possible to obtain the amount of deviation. For example, the amount of deviation can be calculated by using the crank angle when the intake pressure Pin exhibits a peak value as a reference and comparing the actual value with a preset reference value.

  In the above embodiment, the cylinder intake air is stored using the map M2 that stores the relationship between the effective valve lift amount VL ′ (n), the engine speed NE, and the engine load KL and the cylinder intake air amount MC (n). The amount MC (n) was calculated. Such in-cylinder intake air amount MC (n) may be calculated using a physical model that simulates the physical behavior of the intake system. That is, by substituting the effective valve lift amount VL ′ (n) calculated from the difference between the actual phase of the intake pressure pulsation and the reference phase, the current engine speed NE, the engine load KL, etc. into the parameters of the physical model, The in-cylinder intake air amount MC (n) secured in the current situation may be estimated and obtained.

  In the above embodiment, the actual phase of the intake pressure pulsation is obtained using the detected value of the intake pressure Pin over the entire period from the start to the end of the intake stroke of each cylinder, but the calculation of the actual phase is different from that. The detected value of the intake pressure Pin during the period may be used. For example, the actual phase is calculated using only the detected value of the intake pressure Pin during a part of the intake stroke, or the actual phase is calculated using the detected value of the intake pressure Pin before the start of the intake stroke. Anyway.

  In the embodiment described above, correction based on the deviation amount is performed only when the deviation amount between the actual phase of the intake pulsation and the reference phase is equal to or greater than a certain value (ΔAPin ≧ k). Such a correction may be performed in all cases where the value is larger than "." Further, the reference value for determining the necessity of such correction may be made variable according to the valve lift amount instruction value VLo and the engine operating state.

  In the above embodiment, the valve lift amount instruction value VLo (n) is corrected according to the amount of deviation between the actual phase of the intake pressure pulsation and the reference phase, and the corrected valve lift amount instruction value VLo (n) is used. By calculating the fuel injection amount TAU based on the in-cylinder intake air amount MC (n) obtained in this way, the influence of the change over time in the effective valve lift amount VL ′ is reflected in the fuel injection amount control. Similar fuel injection amount control can be performed by reflecting the deviation amount in the fuel injection amount TAU in another manner. For example, the same fuel injection amount control can be performed by correcting the in-cylinder intake air amount MC (n) calculated using the valve lift amount instruction value VLo (n) as it is according to the deviation amount. Further, the in-cylinder intake air amount MC (n) is calculated from the valve lift amount instruction value VLo (n), and the fuel injection amount TAU calculated using the calculated in-cylinder intake air amount MC (n) is a deviation amount. Similar fuel injection amount control can be performed by performing correction according to the above.

  In the above embodiment, the case where the control device of the present invention is applied to the internal combustion engine 10 having the configuration in which the injector 26 is provided in the intake passage 20 has been described. However, the control device of the present invention is a cylinder injection type internal combustion engine. It can be similarly applied to.

  In the above embodiment, the present invention is embodied as a control device for an internal combustion engine including four cylinders # 1 to # 4. However, the present invention is embodied as a control device for an internal combustion engine including other numbers of cylinders. Is also possible.

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 12 ... Combustion chamber, 14 ... Piston, 16 ... Crankshaft, 20 ... Intake passage, 21 ... Surge tank, 22 ... Throttle valve, 24 ... Throttle motor, 26 ... Injector, 28 ... Intake valve, 30 ... Spark plug, 32 ... exhaust passage, 40 ... intake camshaft, 42 ... lift amount variable mechanism, 44 ... actuator, 50 ... crank sensor, 52 ... accelerator pedal, 53 ... accelerator sensor, 54 ... throttle sensor, 56 ... pressure sensor, 60 ... Electronic control unit, 62 ... Phase difference detection process, 63 ... Memory, 64 ... Valve lift amount correction process, 66 ... In-cylinder intake air amount calculation process, 68 ... Fuel injection amount calculation process, # 1-4, #n …cylinder.

Claims (4)

In a control device for controlling a fuel injection amount of an internal combustion engine having a variable lift amount mechanism for adjusting a valve lift amount of an intake valve,
Compare the actual phase, which is the actual value of the phase of the intake pressure pulsation that occurs in the intake passage, with the reference phase that is preset as the reference value of the phase of the intake pressure pulsation, and the amount of deviation between the actual phase and the reference phase A control device for an internal combustion engine, wherein the fuel injection amount is corrected based on The control apparatus for an internal combustion engine according to claim 1,
The lift amount variable mechanism adjusts the valve lift amount based on a valve lift amount instruction value,
The fuel injection amount is controlled based on the valve lift amount instruction value,
When correcting the fuel injection amount, the valve lift amount instruction value is corrected based on the deviation amount to calculate an effective valve lift amount, and based on the effective valve lift amount instead of the valve lift amount instruction value. A control apparatus for an internal combustion engine, wherein the fuel injection amount is corrected. The control device for an internal combustion engine according to claim 1 or 2,
The control apparatus for an internal combustion engine, wherein the intake passage includes a pressure sensor that detects an intake pressure in the intake passage, and calculates the actual phase based on a detection value of the pressure sensor. The control device for an internal combustion engine according to claim 1 or 2,
A control apparatus for an internal combustion engine, comprising: a pressure sensor that detects a pressure in a cylinder of the internal combustion engine; and calculating the actual phase based on a detection value of the pressure sensor.