JP2006214349A - Fuel injection control device for internal combustion engine - Google Patents

Abstract

A fuel injection control device for an internal combustion engine capable of suppressing a decrease in accuracy of a required wall surface adhesion amount and an adverse effect on the fuel injection control associated therewith is provided.
A fuel for a change in a maximum lift amount and an operating angle of an intake valve 9 includes a port adhesion, which is fuel adhesion around an intake port 3a, and a cylinder adhesion, which is fuel adhesion to a combustion chamber 2. The changing tendency of the adhesion amount is different. In view of these points, the port adhesion amount P and the in-cylinder adhesion amount T are respectively calculated as values corresponding to the maximum lift amount and the operating angle based on the operating angle vcam representing the maximum lift amount and the operating angle. The wall surface adhesion amount H is obtained based on the adhesion amount P and the in-cylinder adhesion amount T. Here, the port adhesion amount P and the in-cylinder adhesion amount T are calculated based on the maximum lift amount and the operating angle, respectively, and the fuel adhesion with respect to the change in the maximum lift amount and the operating angle between the port adhesion and the in-cylinder adhesion. It is a value that takes into account the difference in the amount of change.
[Selection] Figure 1

Description

  The present invention relates to a fuel injection control device for an internal combustion engine.

  In an internal combustion engine such as an automobile engine, fuel is injected from a fuel injection valve in accordance with the engine load, that is, the amount of air taken into the combustion chamber per cycle of the engine. It does not mean that part of it adheres to the wall as unburned fuel. For example, in a port injection internal combustion engine in which fuel is injected toward an intake port, the injected fuel adheres around the intake port, and the fuel attached around the intake port further passes through the intake port. And is attached to the cylinder inner wall and the piston head in the combustion chamber.

  In this way, a part of the fuel injected from the fuel injection valve adheres around the intake port and the wall surface of the combustion chamber, so that the fuel injection valve supplies an amount of fuel necessary for setting the air-fuel ratio of the internal combustion engine to the target value. It is impossible to control the air-fuel ratio of the engine to the target value only by injecting from the engine. For this reason, in order to control the air-fuel ratio of the internal combustion engine to the target value, the wall surface adhesion amount that is the amount of fuel adhering to the wall surface is obtained based on the engine load and the like, and the fuel is injected in consideration of the wall surface adhesion amount. Has been done. The reason why the wall surface adhering amount can be obtained based on the engine load or the like is that the fuel injection amount changes according to the engine load, and the amount of fuel adhering around the intake port or on the wall surface in the combustion chamber also changes. is there.

In recent years, as shown in Patent Document 1, an internal combustion engine in which the maximum lift amount and the operating angle of the intake valve are variable has also been proposed. In such an internal combustion engine, the wall surface adhesion amount is obtained and the wall surface adhesion amount is determined. It is desired to perform fuel injection in consideration. In the case of an internal combustion engine in which the maximum lift amount and operating angle of the intake valve are variable, if the maximum lift amount and operating angle change, the opening area of the intake port and the flow velocity of air passing through the intake port change. Even if the injection amount is constant, the wall surface adhesion amount changes. For this reason, the wall surface adhesion amount of the internal combustion engine is obtained in consideration of not only the engine load and the like but also the maximum lift amount and the operating angle. For example, referring to a map that defines the transition of the wall surface adhesion amount with respect to the change in the maximum lift amount and operating angle of the intake valve, the wall surface adhesion amount can be calculated based on the maximum lift amount and operating angle. Conceivable.
JP 2001-263015 A

  However, it is difficult to make the wall surface adhesion amount calculated as described above accurate. This is because the fuel injected from the fuel injection valve adheres to the port, which is fuel adhering around the intake port, and to the cylinder inner wall and piston head in the combustion chamber (inside the cylinder). This is because the amount of fuel adhering to the cylinder is determined as a wall surface adhering amount all at once, although it is divided into certain in-cylinder adhesion.

  Here, the tendency of change in the fuel adhesion amount with respect to the change in the maximum lift amount and the operating angle differs between the port adhesion and the cylinder adhesion. That is, in the port attachment, the smaller the maximum lift amount and the operating angle and the smaller the opening area of the intake port when the intake valve is opened, the more air accumulates on the back surface of the umbrella portion of the intake valve and the like. It becomes easy to adhere. Therefore, the port adhesion amount, which is the amount of fuel adhering around the intake port, is greatly influenced by the change in the air retention state on the rear surface of the umbrella portion of the intake valve and the like accompanying the change in the maximum lift amount and the operating angle. . In addition, in the in-cylinder adhesion, the smaller the maximum lift amount and the operating angle and the smaller the opening area of the intake port when the intake valve is opened, the faster the flow velocity of the air passing through the intake port, The fuel adhering around the intake port by air is blown off into the combustion chamber and easily adheres to the cylinder inner wall and the piston head. Therefore, the in-cylinder adhesion amount, which is the amount of fuel adhering to the cylinder inner wall and piston head in the combustion chamber, is greatly influenced by the change in the air flow velocity at the intake port accompanying the change in the maximum lift amount and the operating angle. receive. Thus, the factors affecting the port lift amount and the cylinder stick amount differ when the maximum lift amount and operating angle change, and this difference is the amount of fuel attached to both the maximum lift amount and operating angle change. It is speculated that it appears as a difference in the change tendency.

  Accordingly, when both the port adhesion amount and the in-cylinder adhesion amount are collectively calculated as the wall surface adhesion amount based on the maximum lift amount and the operating angle as described above, the maximum for the port adhesion and the in-cylinder adhesion is calculated. The difference in the tendency of the fuel adhesion amount to change with respect to the lift amount and the operating angle is not taken into account, and it is inevitable that the accuracy of the wall surface adhesion amount deteriorates due to this. When the accuracy of the wall surface adhesion amount is deteriorated, the fuel injection control performed based on the wall surface adhesion amount is adversely affected.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a fuel for an internal combustion engine that can suppress a reduction in accuracy of the required wall surface adhesion amount and an adverse effect on fuel injection control associated therewith. To provide an injection control device.

In the following, means for achieving the above object and its effects are described.
In order to achieve the above object, the invention according to claim 1 is applied to an internal combustion engine in which the maximum lift amount and operating angle of the intake valve are variable, and injection from a fuel injection valve that injects fuel toward the intake port. In a fuel injection control device for an internal combustion engine that calculates a wall surface adhesion amount that is an amount of fuel that adheres to a wall surface of fuel and performs fuel injection in consideration of the wall surface adhesion amount, the wall surface adhesion amount is around the intake port. The port adhesion amount, which is the amount of fuel adhering, and the in-cylinder adhesion amount, which is the amount of fuel adhering to the cylinder of the internal combustion engine, are obtained, and the port adhesion amount and the in-cylinder adhesion amount are determined by the intake valve. Based on the maximum lift amount and operating angle, the values corresponding to the maximum lift amount and operating angle were calculated.

  The tendency of the fuel adhesion amount to change with respect to the change of the maximum lift amount and the operating angle of the intake valve differs between the port adhesion, which is the fuel adhesion around the intake port, and the cylinder adhesion, which is the fuel adhesion to the cylinder. This is because the factors affected when the maximum lift amount and the operating angle change are different between the port adhesion amount and the in-cylinder adhesion amount, and this difference is the amount of fuel adhesion between the maximum lift amount and the change in the operating angle. It is presumed that it appears as a difference in the change tendency. According to the above configuration, the port adhesion amount and the in-cylinder adhesion amount are calculated as values corresponding to the maximum lift amount and the operation angle based on the maximum lift amount and the operation angle, respectively. The amount of wall surface adhesion is determined based on the amount. Here, since the port adhesion amount and the in-cylinder adhesion amount are calculated based on the maximum lift amount and the operating angle, respectively, the fuel with respect to the change in the maximum lift amount and the operating angle between the port attachment and the in-cylinder adhesion is calculated. It is a value that takes into account the difference in the change in the amount of adhesion. Therefore, due to the difference in the change tendency of the fuel adhesion amount between the port adhesion and the in-cylinder adhesion, the accuracy of the wall surface adhesion amount required based on the port adhesion amount and the in-cylinder adhesion amount is reduced. The adverse effect on the accompanying fuel injection control can be suppressed.

  According to a second aspect of the present invention, in the first aspect of the invention, in the internal combustion engine, in addition to the maximum lift amount and the operating angle of the intake valve, the valve timing of the intake valve is variable. The port adhesion amount and the in-cylinder adhesion amount are each calculated in consideration of the valve timing of the intake valve.

  The port adhesion amount and the in-cylinder adhesion amount are also affected by the valve timing of the intake valve, but the magnitude of the effect differs between the two. For this reason, there is not only a difference in the change tendency with respect to the change in the maximum lift amount and the operating angle between the port attachment amount and the cylinder attachment amount, but also the difference in the influence of the valve timing of the intake valve. This may occur, and this may lead to a decrease in accuracy of the wall surface adhesion amount obtained based on the port adhesion amount and the in-cylinder adhesion amount. However, according to the above configuration, the port adhesion amount and the in-cylinder adhesion amount are calculated in consideration of the valve timing of the intake valve. For this reason, the calculated port adhesion amount and in-cylinder adhesion amount can be values that take into account the difference in the magnitude of the influence of the valve timing, thereby suppressing the above-described decrease in accuracy of the wall surface adhesion amount. it can.

Hereinafter, an embodiment in which the present invention is applied to an automobile engine will be described with reference to FIGS.
In the engine 1 shown in FIG. 1, air is sucked into the combustion chamber 2 through the intake passage 3, and fuel is injected from the fuel injection valve 4 toward the intake port 3a. When the mixture of air and fuel burns in the combustion chamber 2, the piston 6 reciprocates due to the combustion energy at that time, and the crankshaft 7 that is the output shaft of the engine 1 rotates. The air-fuel mixture after combustion is sent out from the combustion chamber 2 to the exhaust passage 8 as exhaust.

  In the engine 1, the intake port 3 a of the intake passage 3 is opened and closed by an intake valve 9, and the exhaust port 8 a of the exhaust passage 8 is opened and closed by an exhaust valve 10. The intake valve 9 and the exhaust valve 10 are opened and closed in accordance with the rotation of the intake camshaft 11 and the exhaust camshaft 12 to which the rotation of the crankshaft 7 is transmitted.

  The intake camshaft 11 is provided with a variable valve timing mechanism 13 that adjusts the relative rotational phase of the intake camshaft 11 with respect to the crankshaft 7 to advance or retard the valve timing of the intake valve 9. FIG. 2 shows how the valve timing of the intake valve 9 is changed by driving the variable valve timing mechanism 13. As can be seen from this figure, when the valve timing of the intake valve 9 is changed, the valve opening timing and the valve closing timing of the valve 9 are both advanced or retarded while the valve opening period of the intake valve 9 is kept constant. The Rukoto.

  Between the intake valve 9 of the intake camshaft 11, there is a lift amount variable mechanism 14 that makes the maximum lift amount and operating angle of the valve 9 variable (the operating angle of the intake cam 11 a that opens and closes the intake valve 9). Is provided. FIG. 3 shows how the maximum lift amount and the operating angle of the intake valve 9 are changed by driving the lift amount variable mechanism 14. As can be seen from the figure, the maximum lift amount and the operating angle of the intake valve 9 change in synchronization with each other. For example, the maximum lift amount decreases as the operating angle decreases. The fact that the operating angle becomes smaller means that the opening timing and closing timing of the intake valve 9 approach each other, and that the opening period of the intake valve 9 becomes shorter.

  Various controls of the engine 1 are performed by an electronic control unit 26 mounted on the automobile. The electronic control unit 26 includes a CPU that executes arithmetic processing related to the control of the engine 1, a ROM that stores programs and data necessary for the control, a RAM that temporarily stores arithmetic results of the CPU, and an external interface. The input / output port for inputting / outputting the signal is provided.

Various sensors shown below are connected to the input port of the electronic control unit 26.
An accelerator position sensor 28 that detects the amount of depression (accelerator depression amount) of the accelerator pedal 27 that is depressed by the driver of the automobile.

A throttle position sensor 30 that detects the opening (throttle opening) of the throttle valve 29 provided in the intake passage 3.
A water temperature sensor 31 that detects the cooling water temperature of the engine 1.

An air flow meter 32 for detecting the amount of air taken into the combustion chamber 2 through the intake passage 3;
A crank position sensor 34 that outputs a signal corresponding to the rotation of the crankshaft 7 and is used for calculation of the engine rotation speed or the like.

A cam position sensor 35 that outputs a signal corresponding to the rotational position of the intake camshaft 11.
A drive circuit for the fuel injection valve 4, the variable valve timing mechanism 13, the variable lift amount mechanism 14, and the throttle valve 29 is connected to the output port of the electronic control unit 26.

  Then, the electronic control unit 26 grasps the engine operation state based on the detection signals input from the various sensors, and outputs command signals to various drive circuits connected to the output port according to the grasped engine operation state. . Thus, the electronic control unit 26 controls the fuel injection amount from the fuel injection valve 4, the valve timing control of the intake valve 9, the maximum lift amount and operating angle of the intake valve 9, the opening control of the throttle valve 29, and the like. Implemented through.

  In the fuel injection amount control of the engine 1, fuel injection from the fuel injection valve 4 is performed according to the engine load, that is, the amount of air taken into the combustion chamber 2 per cycle of the engine 1. However, not all of the fuel injected from the fuel injection valve 4 is burned, and some of the fuel adheres to the wall surface as unburned fuel. For this reason, it is impossible to control the air-fuel ratio of the engine 1 to the target value simply by injecting the fuel necessary for setting the air-fuel ratio of the engine 1 to the target value from the fuel injection valve 4. In order to cope with such a problem, a wall surface adhesion amount which is the amount of fuel adhering to the wall surface is obtained, and fuel is injected in consideration of the wall surface adhesion amount.

  The wall surface adhering amount is obtained based on the engine load, which is a parameter related to the fuel injection amount from the fuel injection valve, but the valve timing of the intake valve 9 such as the valve timing, the maximum lift amount, and the operating angle of the intake valve 9 Since the value varies depending on the characteristics, the calculation is performed in consideration of such valve characteristics. Specifically, prepare a map that defines the transition of the amount of adhesion to the wall with respect to changes in engine load and valve characteristics, and calculate the amount of adhesion on the wall with reference to the map based on the actual engine load and valve characteristics. Can be considered.

  However, in the calculation of the wall surface adhesion amount described above, the port adhesion amount, which is the amount of fuel adhering to the intake port 3a, and the fuel amount adhering to the cylinder inner wall or piston head in the combustion chamber 2 (in the cylinder). The in-cylinder adhesion amount is collectively calculated as the wall surface adhesion amount.

  Here, the maximum lift amount of the intake valve 9 and the attachment of the fuel around the intake port 3a and the attachment of the fuel to the cylinder inner wall and the piston head in the combustion chamber 2 are determined as follows. The change tendency of the fuel adhesion amount with respect to the change of the operating angle is different. That is, in the port attachment, as the maximum lift amount and the operating angle become smaller and the opening area of the intake port 3a when the intake valve 9 is opened becomes smaller, the air stays on the back surface of the umbrella portion of the intake valve 9 and the like. As a result, fuel tends to adhere. For this reason, the amount of port adhesion is greatly affected by the change in the air retention state on the back surface of the umbrella portion of the intake valve 9 and the like accompanying the change in the maximum lift amount and the operating angle. In addition, in the in-cylinder adhesion, the flow rate of the air passing through the intake port 3a becomes faster as the maximum lift amount and the operating angle become smaller and the opening area of the intake port 3a becomes smaller when the intake valve 9 is opened. Thus, the fuel adhering around the intake port by the air is blown into the combustion chamber 2 and easily adheres to the cylinder inner wall and the piston head. For this reason, the in-cylinder adhesion amount is greatly affected by the change in the air flow velocity at the intake port 3a accompanying the change in the maximum lift amount and the operating angle. Thus, the port adhesion amount and the in-cylinder adhesion amount differ in the factors that are affected when the maximum lift amount and the operating angle change, and this difference is the difference in the fuel adhesion between the maximum lift amount and the operating angle. It is presumed that it appears as a difference in the amount of change.

  Accordingly, when both the port adhesion amount and the in-cylinder adhesion amount are collectively calculated as the wall surface adhesion amount based on the maximum lift amount and the operating angle, the maximum lift amount and the operating angle for the port adhesion and the in-cylinder adhesion are calculated. The difference in the change tendency of the fuel adhesion amount with respect to this change is not considered, and it is inevitable that the accuracy of the wall surface adhesion amount deteriorates due to this.

  Further, the port adhesion amount and the in-cylinder adhesion amount are also affected by the valve timing of the intake valve 9, but the magnitude of the influence differs between the two. For this reason, not only the difference in the change tendency with respect to the change in the maximum lift amount and the operating angle, but also the difference in the influence of the valve timing of the intake valve occurs between the port attachment amount and the cylinder attachment amount. In other words, this may lead to a decrease in accuracy of the wall surface adhesion amount obtained based on the port adhesion amount and the in-cylinder adhesion amount.

  Therefore, in the present embodiment, the port adhesion amount and the in-cylinder adhesion amount are calculated as values corresponding to the maximum lift amount and the operating angle based on the maximum lift amount and the operating angle of the intake valve 9, and the respective calculations are performed. In this case, the valve timing of the intake valve 9 is also taken into consideration.

  As a result, the calculated port adhesion amount and in-cylinder adhesion amount are calculated in consideration of the difference in the tendency of change in the fuel adhesion amount with respect to the change in the maximum lift amount and the operating angle, and further the magnitude of the influence of the valve timing. It can be a value that takes into account the difference. Therefore, the tendency of the change in the amount of fuel adhering to the maximum lift amount and the change in the operating angle is different between the port adhesion and the in-cylinder adhesion, and the influence of the valve timing on the fuel adhesion amount is different from that in the port adhesion and It can be suppressed that the accuracy of the wall surface adhesion amount required based on the port adhesion amount and the in-cylinder adhesion amount is deteriorated due to the difference in the internal adhesion.

  Next, the detailed calculation procedure of the wall surface adhesion amount will be described with reference to the flowchart of FIG. 4 showing the wall surface adhesion amount calculation routine. This wall surface adhesion amount calculation routine is executed through the electronic control unit 26 by, for example, an angle interruption for each predetermined crank angle.

  In this routine, the wall surface adhesion amount H is calculated based on the port adhesion amount P and the in-cylinder adhesion amount T. Steps S101 to S103 are processes for calculating the port adhesion amount P, and steps S104 to S106 are performed. This is a process for calculating the in-cylinder adhesion amount T. In step S107, based on the calculated port adhesion amount P and in-cylinder adhesion amount T, the wall surface adhesion amount H is calculated using the equation “H = P + T (1)”. Hereinafter, details of the calculation process (S101 to S103) of the port adhesion amount P necessary for calculating the wall adhesion amount H and the calculation process (S104 to S106) of the in-cylinder adhesion amount T will be described in order.

[Calculation processing of port adhesion amount P (S101 to S103)]
In this process, first, the base value q1 of the port adhesion amount P is calculated based on the opening timing ivo of the intake valve 9 and the engine load KL with reference to the map of FIG. 5 (S101). Here, the valve opening timing ivo corresponds to the valve timing of the intake valve 9 and is a value that changes through driving of the variable valve timing mechanism 13 and driving of the variable lift amount mechanism 14. The valve opening timing ivo is obtained based on detection signals from the cam position sensor 35 and the crank position sensor 34. The engine load KL is a value used for fuel injection amount control. The engine load KL is calculated based on the intake air amount of the engine 1 determined based on detection signals from the accelerator position sensor 28, the throttle position sensor 30, the air flow meter 32, and the like, and the engine rotation determined based on the detection signal of the crank position sensor 34. Calculated from speed.

  As can be seen from FIG. 5, regarding the calculated base value q1 (port adhesion amount P), it is considered that the fuel adhering around the intake port 3a increases as the engine load KL increases and the fuel injection amount increases. Then, as the engine load KL increases corresponding to such a tendency of fuel adhesion, the value increases. The base value q1 is variable not only according to the engine load KL but also according to the valve opening timing ivo of the intake valve 9, in other words, the valve timing of the intake valve 9, and decreases to a smaller value as the valve opening timing ivo advances. It will change. The fuel adhesion around the intake port 3 a is greatly influenced by the valve timing of the intake valve 9. Therefore, by calculating the base value q1 based on the valve timing (opening timing ivo) of the intake valve 9 as described above, the base value q1 becomes a value that takes into account the influence of the valve timing.

  After the calculation of the base value q1, referring to the map of FIG. 6 based on the engine load KL and the operating angle vcam of the intake valve 9, the base value q1 is corrected according to the maximum lift amount and operating angle of the intake valve 9. An operating angle correction coefficient k1 for performing the above is calculated (S102). Here, the operating angle vcam is a value that changes in synchronization with the maximum lift amount of the intake valve 9 in accordance with the drive of the variable lift amount mechanism 14, and is obtained based on the drive state of the variable lift amount mechanism 14.

  As can be seen from FIG. 6, the calculated operating angle correction coefficient k1 is a value that increases as the engine load KL increases and the fuel injection amount increases, in other words, a value that corrects the base value q1 to the increase side. . Further, the operating angle correction coefficient k1 is variable not only according to the engine load KL but also according to the operating angle vcam, and increases to a larger value (a value that corrects the base value q1 to the increase side) as the operating angle vcam decreases. It will change. In the fuel adhesion around the intake port 3a, the smaller the opening area of the intake port 3a when the intake valve 9 is opened as the maximum lift amount and operating angle of the intake valve 9 decrease, the smaller the back surface of the umbrella portion of the intake valve 9 As a result, air stays and the fuel tends to adhere. Therefore, by calculating the operating angle correction coefficient k1 based on the operating angle vcam as described above, the base value q1 (port adhesion amount P) corrected by the operating angle correction coefficient k1 becomes the maximum lift amount and the operating angle. Is calculated as a value corresponding to. That is, the map of FIG. 6 is defined in advance based on experiments and the like so that the operating angle correction coefficient k1 is calculated as such a value.

  After the calculation of the base value q1 and the operating angle correction coefficient k1 as described above, the port adhesion amount P is calculated using the equation “P = q1 · k1 + A (2)”. The correction term A used in the equation (2) is a parameter that affects the port adhesion amount P other than parameters such as the engine load KL, the valve opening timing ivo, and the operating angle vcam port adhesion amount P, for example, engine rotation It is a correction term calculated based on speed and cooling water temperature.

[Calculation processing of in-cylinder adhesion amount T (steps S104 to S106)]
In this process, first, the base value q2 of the in-cylinder adhesion amount T is calculated based on the opening timing ivo of the intake valve 9 and the engine load KL with reference to the map of FIG. 7 (S104).

  As can be seen from FIG. 7, the calculated base value q2 (in-cylinder adhesion amount T) adheres to the cylinder inner wall and piston head in the combustion chamber 2 as the engine load KL increases and the fuel injection amount increases. Considering that the amount of fuel to be increased, the value increases as the engine load KL increases corresponding to the tendency of the fuel adhesion. The base value q2 is variable not only according to the engine load KL but also according to the valve opening timing ivo (valve timing) of the intake valve 9, and changes to a smaller value as the valve opening timing ivo advances. . The fuel adhesion to the cylinder inner wall and the piston head in the combustion chamber 2 is greatly affected by the valve timing of the intake valve 9. Therefore, by calculating the base value q2 based on the valve timing (opening timing ivo) of the intake valve 9 as described above, the base value q2 becomes a value that takes into account the influence of the valve timing.

  After the calculation of the base value q2, the map in FIG. 8 is referred to based on the valve opening timing ivo and the operating angle vcam of the intake valve 9, and the base value q2 is determined according to the maximum lift amount and the operating angle of the intake valve 9. An operating angle correction coefficient k2 for performing correction is calculated (S105).

  As can be seen from FIG. 8, the calculated operating angle correction coefficient k2 changes to a larger value as the operating angle vcam decreases, in other words, a value that corrects the base value q2 to the increase side. In the fuel adhesion to the cylinder inner wall, the piston and the like in the combustion chamber 2, the following tendency is exhibited as the maximum lift amount and the operating angle of the intake valve 9 decrease. That is, as the maximum lift amount and the operating angle are reduced, the opening area of the intake port 3a when the intake valve 9 is opened becomes smaller and the flow velocity of the air passing through the intake port 3a becomes faster. More fuel adhering around the port 3a is blown off in the combustion chamber 2 and easily adheres to the cylinder inner wall and the piston head. Therefore, by calculating the operating angle correction coefficient k2 based on the operating angle vcam as described above, the base value q2 (in-cylinder adhesion amount T) corrected by the operating angle correction coefficient k2 becomes the maximum lift amount and the operation. Calculated as a value corresponding to a corner. That is, the map of FIG. 8 is defined in advance based on experiments or the like so that the operating angle correction coefficient k2 is calculated as such a value.

  The operating angle correction coefficient k2 is variable not only according to the operating angle vcam of the intake valve 9 but also according to the valve opening timing ivo (valve timing), and increases as the valve opening timing ivo increases (base value q1). To a value that compensates for more increase). The fuel adhesion on the cylinder inner wall and the piston head in the combustion chamber 2 is greatly affected by the valve timing of the intake valve 9. Therefore, by calculating the operating angle correction coefficient k2 based on the valve timing (valve opening timing ivo) of the intake valve 9 as described above, the base value q2 corrected by the operating angle correction coefficient k2 is determined by the valve timing. The value takes into account the effect.

  After calculating the base value q2 and the operating angle correction coefficient k2 as described above, the in-cylinder adhesion amount T is calculated using the equation “T = q2 · k2 + B (3)”. The correction term B used in the equation (3) is a parameter that affects the in-cylinder adhesion amount T other than parameters such as the engine load KL, the valve opening timing ivo, and the operating angle vcam port adhesion amount P, for example, the engine It is a correction term calculated based on the rotation speed and the cooling water temperature.

According to the embodiment described in detail above, the following effects can be obtained.
(1) Port adhesion, which is fuel adhesion around the intake port 3a, and in-cylinder adhesion, which is fuel adhesion to the combustion chamber 2 (in-cylinder), have a maximum lift amount and an operating angle of the intake valve 9. The change tendency of the fuel adhesion amount to the change is different. This is because the factors affected when the maximum lift amount and the operating angle change are different between the port adhesion amount P and the in-cylinder adhesion amount T, and this difference is the difference between the two fuels for the change in the maximum lift amount and the operation angle. This is presumably because it appears as a difference in the change in the amount of adhesion. In view of these points, the port adhesion amount P and the in-cylinder adhesion amount T are respectively calculated as values corresponding to the maximum lift amount and the operating angle based on the operating angle vcam representing the maximum lift amount and the operating angle. The wall surface adhesion amount H is obtained based on the adhesion amount P and the in-cylinder adhesion amount T. Here, the port adhesion amount P and the in-cylinder adhesion amount T are calculated based on the maximum lift amount and the operating angle, respectively, and the fuel adhesion with respect to the change in the maximum lift amount and the operating angle between the port adhesion and the in-cylinder adhesion. It is a value that takes into account the difference in the amount of change. Therefore, the accuracy of the wall surface adhesion amount H obtained based on the port adhesion amount P and the cylinder adhesion amount T is reduced due to the difference in the change tendency of the fuel adhesion amount between the port adhesion and the cylinder adhesion. And the bad influence to the fuel injection amount control accompanying it can be suppressed.

  (2) Although the port adhesion amount P and the in-cylinder adhesion amount T are also affected by the valve opening timing ivo (valve timing) of the intake valve 9, the magnitude of the influence differs between the two. Therefore, between the port adhesion amount P and the in-cylinder adhesion amount T, not only the difference in change tendency with respect to the change in the maximum lift amount and the operating angle, but also the magnitude of the influence of the valve timing of the intake valve 9 is large. This may also cause a difference in accuracy, and this may lead to a decrease in accuracy of the wall surface adhesion amount H obtained based on the port adhesion amount P and the in-cylinder adhesion amount T. However, since the port adhesion amount P and the in-cylinder adhesion amount T are respectively calculated in consideration of the valve timing (valve opening timing ivo) of the intake valve 9, the calculated port adhesion amount P and in-cylinder adhesion amount are The difference in the magnitude of the influence of the valve timing can be taken into consideration, and the above-described decrease in accuracy of the wall surface adhesion amount H can be suppressed.

In addition, the said embodiment can also be changed as follows, for example.
The base value q1 and the operating angle correction coefficient k1 for calculating the port adhesion amount P can be calculated using a calculation formula instead of calculating with reference to the map.

  The base value q2 and the operating angle correction coefficient k2 for calculating the in-cylinder adhesion amount T can also be calculated using a calculation formula instead of calculating with reference to the map.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the whole engine with which the fuel-injection control apparatus of this embodiment is applied. The graph which shows the change aspect of the valve timing of an intake valve based on the drive of a valve timing variable mechanism. The graph which shows the change aspect of the maximum lift amount of an intake valve and the working angle of an intake cam based on the drive of a variable lift amount mechanism. The flowchart which shows the calculation procedure of wall surface adhesion amount. Map used when calculating base value q1 of port adhesion amount P The map used when calculating the operating angle correction coefficient k1 for correcting the base value q1. Map used when calculating the base value q2 of the in-cylinder adhesion amount T The map used when calculating the operating angle correction coefficient k2 for correcting the base value q2.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Combustion chamber, 3 ... Intake passage, 3a ... Intake port, 4 ... Fuel injection valve, 6 ... Piston, 7 ... Crankshaft, 8 ... Exhaust passage, 8a ... Exhaust port, 9 ... Intake valve, 10 DESCRIPTION OF SYMBOLS ... Exhaust valve, 11 ... Intake cam shaft, 11a ... Intake cam, 12 ... Exhaust cam shaft, 13 ... Valve timing variable mechanism, 14 ... Lift amount variable mechanism, 26 ... Electronic control device, 27 ... Accelerator pedal, 28 ... Accelerator position Sensor 29, throttle valve, 30 throttle position sensor, 31 water temperature sensor, 32 air flow meter, 34 crank position sensor, 35 cam position sensor.

Claims (2)

Applicable to internal combustion engines in which the maximum lift amount and operating angle of the intake valve are variable, and the wall surface attachment amount that is the amount of fuel that adheres to the wall surface of the injected fuel from the fuel injection valve that injects fuel toward the intake port In a fuel injection control device for an internal combustion engine that performs fuel injection in consideration of the amount of wall surface adhesion,
The wall surface adhering amount is obtained based on a port adhering amount that is an amount of fuel adhering around the intake port and an in-cylinder adhering amount that is an amount of fuel adhering in the cylinder of the internal combustion engine,
The fuel for the internal combustion engine, wherein the port adhesion amount and the in-cylinder adhesion amount are respectively calculated as values corresponding to the maximum lift amount and operating angle based on the maximum lift amount and operating angle of the intake valve. Injection control device. In the internal combustion engine, in addition to the maximum lift amount and operating angle of the intake valve, the valve timing of the intake valve is variable.
The fuel injection control device for an internal combustion engine according to claim 1, wherein the port adhesion amount and the in-cylinder adhesion amount are each calculated in consideration of a valve timing of the intake valve.

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