JPH084578A - Fuel injection timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide an injection timing control device which is constituted to ensure stable combustion by preventing fuel from colliding with the back of the shade of an intake valve. CONSTITUTION:An effective fuel injection amount (an effective injection pulse width) Te is read (S1). An injection crank angle is calculated (S3). A difference between the injection crank angle theta and a first half maximum angle thetaMAX1 is calculated as an excessive injection crank angle thetaER1 (S4). In a case of thetaER1>0, injection is divided, the first half injection crank angle is set to the first half maximum angle thetaMAX1 and injection is started at an crank angle CA11. At the second half, injection is effected by thetaER1 and injection is completed (S6).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection timing control device for an internal combustion engine, and more particularly to an internal combustion engine configured to control fuel injection timing so that fuel injection is performed by a fuel injection valve in a predetermined injection period. Regarding the institution.

[0002]

2. Description of the Related Art As an internal combustion engine of this type, for example, SA
There is one such as disclosed in EPAPER 940483.
What is shown in this is that a fuel injection valve for injecting fuel toward the vicinity of the back surface of an intake valve provided for each cylinder is provided at the upper part of the cylinder, whereby the fuel is directly injected into the combustion chamber. Is injected into the combustion chamber to form a good mixture in the combustion chamber.

[0003]

However, when injection is performed from the injection valve provided in the upper part of the cylinder, that is, at the end of the combustion chamber, the spray injected from the injection valve when the intake valve reaches the maximum lift. Will come into contact with the intake valve. If the spray comes into contact with the intake valve, the fuel hits the inner surface of the intake valve and the fuel bounces off, which may cause fuel to adhere to the spark plug and the lower surface of the head, and may cause backflow of the fuel into the intake port. When the fuel adheres or the backflow of the fuel occurs, combustion becomes unstable, smoke or HC increases, soot is accumulated and a deposit is generated, and the deposit is caught to cause a valve seal defect. There is a fear that it will occur.

The present invention has been made in view of such a conventional situation, and controls the fuel injection timing so that the injection control of the fuel injection valve is prohibited when the intake valve lift is near the maximum, so that the intake valve is controlled. An object of the present invention is to provide an injection timing control device capable of preventing the fuel from hitting the back of the umbrella and ensuring stable combustion, thereby improving the combustibility of the engine.

[0005]

Therefore, according to the invention of claim 1, at least one intake valve is provided for each cylinder, and a fuel for injecting fuel into each cylinder toward the vicinity of the back surface of the intake valve. An injection valve and a fuel injection amount injected from the fuel injection valve are calculated based on an engine operating state, and the fuel injection valve is controlled according to the fuel injection amount between a predetermined injection start timing and a predetermined injection end timing. A fuel injection timing control device for an internal combustion engine, comprising: a fuel injection control means;
As shown in, when the intake valve lift detection means for detecting the lift of the intake valve and the intake valve lift detected by the intake valve lift detection means are in the vicinity of the maximum, the injection of the fuel injection valve by the fuel injection control means is performed. Prohibition means to prohibit control,
It is configured with.

Further, according to the invention of claim 2, when the injection period of the fuel injection valve drive-controlled by the fuel injection control means is longer than a predetermined period, the injection period is divided and the first half injection is performed. It is also possible to set the fuel injection end timing according to (1) before the period when the injection control is prohibited by the prohibiting means, and set the fuel injection start timing for the latter half injection after the period when the injection control is prohibited by the prohibiting means. Good.

According to the invention of claim 3, when the injection period of the fuel injection valve drive-controlled by the fuel injection control means is longer than a predetermined period, the injection period is divided and the first half injection is performed. The fuel injection start timing according to the above is fixed to a predetermined timing immediately after the intake valve lift detected by the intake valve lift detection means is started, and the fuel injection end timing is delayed as the injection amount increases, and The fuel injection start timing related to the injection may be fixed to a predetermined timing immediately after the period when the injection control is prohibited by the prohibiting means.

Further, according to the invention of claim 4, when the injection period of the fuel injection valve drive-controlled by the fuel injection control means is longer than a predetermined period, the injection period is divided and the latter half injection is performed. The fuel injection end timing according to the above is fixed to a predetermined time after the intake valve lift detected by the intake valve lift detection means is finished, and the fuel injection start timing is advanced as the injection amount increases, and the first half injection is performed. The fuel injection end timing according to the above may be fixed to a predetermined timing immediately before the period in which the injection control is prohibited by the prohibiting means.

Further, according to a fifth aspect of the present invention, the injection period of the fuel injection valve driven and controlled by the fuel injection control means is divided, and the midpoint of the divided injection period is prohibited by the prohibiting means. It may be fixed for a certain period. Further, as a configuration according to the invention of claim 6,
It may be an internal combustion engine having two intake valves for each cylinder.

Further, according to the invention of claim 7, each cylinder is provided with a plurality of intake valves and a plurality of intake ports branched from the middle of the intake passage to reach the respective intake valves. The internal combustion engine may be provided with a fuel injection valve that simultaneously injects fuel in a plurality of directions toward the respective intake ports in the intake passage on the upstream side of the branch portion.

[0011]

According to the first aspect of the present invention, the fuel injection control means controls the fuel injection valve so that the fuel is injected between a predetermined injection start timing and a predetermined injection end timing. When the lift is near the maximum, the injection control of the fuel injection valve is prohibited, so that when the intake valve reaches the maximum lift, the spray injected from the injection valve can be prevented from coming into contact with the intake valve. .

As an operation according to the second aspect of the invention, when the injection period of the fuel injection valve is longer than a predetermined period, the injection period is divided, and the injection control is prohibited for the fuel injection related to the first half injection. Fuel injection related to the latter half of the injection is started after the period when the injection control is prohibited, and when the intake valve reaches the maximum lift,
It is possible to prevent the spray injected from the injection valve from coming into contact with the intake valve.

Further, as an operation according to the invention described in claim 3, when the injection period of the fuel injection valve is longer than a predetermined period, the injection period is divided, and the fuel injection relating to the first half injection is performed by the lift of the intake valve. Is started at a predetermined timing immediately after the start of the fuel injection, and the fuel injection end timing is delayed as the injection amount increases. Then, the fuel injection related to the latter half injection after the period when the injection control is prohibited is also started at a predetermined timing immediately after the period when the injection control is prohibited. It is possible to prevent the injected spray from coming into contact with the intake valve.

As an operation according to the invention described in claim 4, when the injection period of the fuel injection valve is longer than a predetermined period, the injection period is divided, and the fuel injection relating to the latter half of the injection is performed by the lift of the intake valve. Is controlled to end at a predetermined time after the end of the fuel injection, and the fuel injection start timing is advanced as the injection amount increases. Then, the fuel injection related to the first half of the injection before the period when the injection control is prohibited is also controlled so as to end at a predetermined time immediately before the period when the injection control is prohibited, and when the intake valve reaches the maximum lift. The spray injected from the injection valve can be prevented from coming into contact with the intake valve. Further, since the injection control is controlled to be delayed, stratification of the fuel and air is promoted, and stable combustion can be obtained even with a lean air-fuel ratio.

Further, as an operation according to the invention described in claim 5, the injection period of the fuel injection valve is divided mainly around the period in which the injection control is prohibited, and when the intake valve reaches the maximum lift, the injection valve It is possible to prevent the spray injected from contacting the intake valve. Further, even if the injection amount is small, the fuel is surely dispersed and injected, and a good air-fuel mixture is formed in the combustion chamber.

Further, even in an internal combustion engine having two intake valves for each cylinder, the two intake valves are lifted at the same time. Therefore, the operation according to the present invention is the same as that described above. Will be played. Further, as an operation according to the invention described in claim 7, the fuel is simultaneously injected from the fuel injection valve toward the intake port, but the intake port is provided with a plurality of intake valves. Even in this case, the same operation as described above can be achieved.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 showing the configuration of the present embodiment, air is drawn into each cylinder 2 of the engine 1 from an air cleaner 22 through an intake duct 23, a throttle valve 24 and an intake manifold 25. Here, a plurality of, for example, two intake valves 3 and 4 and a plurality of, for example, two exhaust valves 5, are provided for each cylinder 2.
6 is provided, and two intake ports 8 branching from the middle of the intake manifold 25 to reach the intake valves 3 and 4,
9 is formed.

At the positions corresponding to the upper surface 2a of the cylinder 2, that is, the lower surfaces of the intake ports 8 and 9, the intake valves 3 and 4 are provided.
An electromagnetic fuel injection valve 10 for simultaneously injecting fuel in two directions toward a vehicle is mounted integrally with a fuel pipe (not shown). This fuel injection valve 10 is an electromagnetic fuel injection valve that is energized by a solenoid to open the valve, is deenergized and is closed, and is energized and opened by an injection pulse signal from a control unit 40 described later, Fuel that is pressure-fed from a fuel pump (not shown) and adjusted to a predetermined pressure by a pressure regulator is injected and supplied to the engine 1. Fuel injection flow 11, 12 toward each intake valve 3, 4 of the fuel injection valve 10
Points toward the lower side of the spark plug 14 in the center of the combustion chamber 13,
Further, the spray umbrella angle upper end portions 11a, 12a of the fuel injection flows 11, 12 pass directly below the spark plug 14, and the spray umbrella angle lower end portions 11b, 12 are formed.
b is set to an angle such that the fuel injection flows 11 and 12 do not collide with the side wall surface 15 of the cylinder 1.

The ignition plug 14 spark-ignites the mixture to ignite and burn the mixture. And from institution 1,
Exhaust gas is discharged through the exhaust manifold 27 and an exhaust duct (not shown). Control unit 40 is C
A microcomputer including a PU, a ROM, a RAM, an A / D converter, an input / output interface, and the like is provided, receives input signals from various sensors, and determines the fuel injection amount Ti by the fuel injection valve 10 as described later. The fuel injection amount Ti is set by calculation and is set at a predetermined injection timing.
The fuel supply to the engine 1 is electronically controlled by outputting an injection pulse signal corresponding to the above to the fuel injection valve 10.

As the various sensors, the intake duct 23
An air flow meter 41 is provided therein and outputs a signal according to the intake air flow rate Q of the engine 1. Also, a crank angle sensor 42 is provided and outputs a rotation signal for each predetermined crank angle. Here, by measuring the cycle of the rotation signal or the number of occurrences within a predetermined time,
The engine rotation speed Ne can be calculated.

Further, a water temperature sensor 45 for detecting the cooling water temperature Tw of the water jacket of the engine 1 is provided.
In addition, an oxygen sensor that detects the air-fuel ratio of the engine intake air-fuel mixture via the oxygen concentration in the exhaust gas at the collecting portion of the exhaust manifold 27.
46 are provided. Here, the CPU of the microcomputer installed in the control unit 40 is
The basic fuel injection amount Tp is calculated on the basis of the intake air amount Q and the engine rotation speed Ne, while the basic fuel injection amount Tp is corrected according to the engine operating conditions such as the cooling water temperature Tw and the final effective value is obtained. The fuel injection amount (effective injection pulse width) Te is calculated.

Then, conventionally, a predetermined injection start timing Ti
_{In ST} , fuel injection is started, and the effective fuel injection amount Te
The injection pulse signal having the pulse width corresponding to is output to the fuel injection valve 10 to inject the effective fuel injection amount Te, and the fuel injection is ended at the predetermined injection end timing Ti _EN . Here, an embodiment of the fuel injection control which is performed by the control unit 40 and prohibits the injection of the fuel injection valve 10 when the intake valve lift is near the maximum is shown in FIGS.
It will be described according to the flowchart of

FIG. 4 shows the first aspect of the invention according to claim 3.
4 shows a flowchart of an embodiment. Step 1 (S in the figure
Write 1. The same applies hereinafter), the effective fuel injection amount (effective injection pulse width) T calculated by the control unit 40
Read e. In step 2, the engine rotation speed Ne calculated based on the detection signal from the crank angle sensor 42 is read.

In step 3, the fuel injection pulse width Ti (Te is obtained by adding the effective injection pulse width Te read in step 1 to the invalid injection pulse width Ts related to the voltage fluctuation of the battery.
The injection crank angle θ is calculated by dividing (+ Ts) by the engine rotation speed Ne read in step 2. By the way, as shown in FIG. 5, the intake valves 3 and 4 start to lift at the crank angle CA _ST near the top dead center of the intake start and lift up to the maximum lift L _MAX (the crank angle at that time is C
After setting A _MAX ), the lift ends at the crank angle CA _EN near the intake end bottom dead center.

Therefore, the lift of the intake valve can be detected by detecting the crank angle CA.
Therefore, the crank angle sensor 42 functions as the intake valve lift detecting means. And the intake valves 3, 4
Near the maximum lift L _MAX , the injection control of the fuel injection valve 10 is prohibited at the crank angle CA _PR between the crank angle CA ₁ and the crank angle CA ₂ near the crank angle CA _MAX .

That is, the prohibition means is constituted by the structure. Here, in the first embodiment, the injection period of the fuel injection valve 10 which is drive-controlled by the control unit 40 is divided with the crank angle CA _PR sandwiched between the injection periods having a long injection period as described later. It is configured. That is, in order to set the fuel injection end timing relating to the first half injection to a period before the injection control of the fuel injection valve 10 is prohibited,
Since the crank angle CA ₁ is set at the latest and the fuel injection start timing for the latter half of the injection is set to the period after the injection control of the fuel injection valve 10 is prohibited, the crank angle C is set at the earliest.
The configuration is set to A ₂ .

Further, in the first embodiment, the first half
The lift of the intake valves 3 and 4 depends on the fuel injection start timing related to the injection.
The crank angle should be set to the predetermined time immediately after the start.
CA _STCrank angle CA slightly delayed₁₁As
It Where the crank angle CA ₁₁Intake valves 3 and 4 open
And crank angle at which backflow to intake ports 8 and 9 ends
This is true for all areas except the idle operation area.
It is fixed at an angle. In addition, the fuel injection related to the latter half injection
The injection start timing is the period during which the injection control of the fuel injection valve 10 is prohibited.
The crank angle CA should be set immediately after the predetermined time.₂age
It was

Returning to the explanation of FIG. 4 again, in step 4, the difference between the injection crank angle θ calculated in step 3 and the first half maximum angle θ _MAX1 is calculated as the excessive injection crank angle θ _ER1 . Here, the first-half maximum angle θ _MAX1 is an angle at which fuel injection can be maximized in relation to the first-half injection, and is _calculated as follows. θ _MAX1 = CA _{1 −CA 11} Therefore, the over-injection crank angle θ _ER1 is θ _ER1 = θ-θ _{MAX 1} = θ- (CA _{1 -CA 11} ) In step 5, whether the over-injection crank angle θ _ER1 > 0 If YES, the injection crank angle θ is larger than the first half maximum angle θ _MAX1 , that is, the fuel injection valve
It is assumed that the injection is not completed before the period in which the injection control of 10 is prohibited, and the process proceeds to step 6.

Therefore, in step 6, the injection crank angle θ is divided and set as follows. That is, regarding the first-half injection, the first-half injection crank angle is set to the first-half maximum angle θ _MAX1 , and a signal is output to the fuel injection valve 10 to start the injection at the crank angle CA ₁₁ , and the first-half maximum angle θ _{MAX1 is} injected. , The crank angle CA ₁ is set to end the injection. As described above, since the fuel injection pulse width Ti includes the invalid injection pulse width Ts, the fuel injection valve 10 starts fuel injection with a delay of the invalid injection pulse width Ts. .

Regarding the latter half of the injection, the fuel injection valve is advanced at a timing that is earlier by the crank angle corresponding to the invalid injection pulse width Ts in order to start the injection at the crank angle CA ₂ .
A signal is output to 10, and the injection is set to be ended by injecting the excessive injection crank angle θ _ER1 . On the other hand, in step 5, when the excessive injection crank angle θ _ER1 > 0 is not satisfied (NO), the injection crank angle θ is smaller than the first half maximum angle θ _MAX1 , that is, before the period when the injection control of the fuel injection valve 10 is prohibited. In this case, it is assumed that the injection is completed and the process proceeds to step 7.

In step 7, the injection crank angle θ is not divided and set, and for the first half injection, a signal is output to the fuel injection valve 10 to start the injection at the crank angle CA ₁₁ , and only the injection crank angle θ is output. Set to perform injection and end injection. As described above, since the fuel injection pulse width Ti includes the invalid injection pulse width Ts, the fuel injection valve 10 starts the fuel injection with a delay of the invalid injection pulse width Ts.

In step 8, the steps 6 or 7 are performed.
The injection crank angle θ set in step 1 is converted into the corresponding injection pulse time width again, and the injection pulse signal is converted to the fuel injection valve 10
Output to. Therefore, in the first embodiment, as shown in FIG. 5, the fuel injection related to the first half injection is started at the crank angle CA ₁₁ immediately after the crank angle CA _ST at which the lift of the intake valve is started, and the injection amount Ti is increased. Therefore, the maximum is
Up to the crank angle CA ₁ near the crank angle CA _MAX ,
The fuel injection end timing is delayed. When the injection is required to be performed longer than the first half maximum angle θ _MAX1 , the fuel injection related to the latter half of the injection is also performed at the crank angle CA ₂
Will be started. That is, the crank angle CA from the crank angle CA ₁ to the crank angle CA _{2 in the} vicinity of the crank angle CA _{MAX at} which the intake valves 3 and 4 have the maximum lift.
_{In PR} , the injection control of the fuel injection valve 10 is prohibited, and it is possible to prevent the spray injected from the fuel injection valve 10 from coming into contact with the umbrella backs of the intake valves 3 and 4. So,
Combustion of the engine is improved such as stabilization of combustion and reduction of smoke and HC, and therefore, the effects of suppressing the generation of deposits and ensuring the valve sealability can be achieved.

FIG. 6 shows a second embodiment of the invention according to claim 4.
4 shows a flowchart of an embodiment. The steps having the same functions as those in the flowchart according to the first embodiment shown in FIG. 4 are given the same step numbers and the description thereof will be omitted. Intake valves 3 and 4 as shown in FIG. 7, to start lifting at the crank angle CA _ST near the start TDC intake, maximum lift L
Lifted to _MAX (Crank angle at that time is CA _MAX
Crank angle CA _EN near the bottom dead center after intake end
To end the lift.

In the vicinity of the maximum lift L _{MAX of the} intake valves 3 and 4, at the crank angle CA _PR between the crank angle CA ₁ and the crank angle CA ₂ near the crank angle CA _MAX , the fuel injection valve 10 Injection control is prohibited. Here, in the second embodiment, the injection period of the fuel injection valve 10 which is drive-controlled by the control unit 40 is divided with the crank angle CA _PR sandwiched between the injection periods having a long injection period as described later. It is configured. That is, in order to set the fuel injection end timing for the first half injection before the period when the injection control of the fuel injection valve 10 is prohibited, the crank angle CA ₁ is set at the latest, and the fuel injection start timing for the second half injection is set to the fuel injection start timing. In order to be after the period when the injection control of the injection valve 10 is prohibited, the crank angle CA ₂ is set at the earliest.

Further, in the second embodiment, the intake end bottom dead center TDC is set so that the fuel injection end timing relating to the latter half injection is set to a predetermined time after the lift of the intake valves 3 and 4 is finished.
The crank angle CA ₃ in the compression stroke between ₁ and the compression start top dead center TDC ₂ is fixed to advance the fuel injection start timing as the injection amount increases, and also the fuel injection end timing relating to the first half injection. Is set to the crank angle CA ₁ so as to be a predetermined timing immediately before the period when the injection control of the fuel injection valve 10 is prohibited.

In step 24, the jet calculated in step 3
Fire crank angle θ and maximum angle in the latter half θ _MAX2Excessive difference from
Injection crank angle θ_ER2Calculate as Where the second half
Maximum angle θ_MAX2Is the maximum fuel injection related to the latter half of the injection
It is the angle that can be limited, and is calculated as follows. θ_MAX2= CA₃-CA₂ Therefore, the excessive injection crank angle θ_ER2Is θ_ER2= Θ-θ_MAX2= Θ- (CA₃-CA₃) In step 25, the excessive injection crank angle θ_ER2> 0
Whether or not the injection crank angle
θ is the latter half maximum angle θ_MAX2Greater than, i.e. fuel injection valve
Injection is performed only after the period when 10 injection controls are prohibited
If not, go to step 26.

In step 26, the injection crank angle θ is divided and set as follows. First, the latter half injection will be described. Regarding the latter half injection, the latter half injection crank angle is set as the latter half maximum angle θ _MAX2 , and the latter half maximum angle θ _{MAX2 is} injected, and the injection is ended at the crank angle CA ₃ .
The fuel injection valve 10 is set to output a signal at the crank angle CA ₂ . As described above, since the fuel injection pulse width Ti includes the invalid injection pulse width Ts, the fuel injection valve 10 has to start effective injection at the crank angle CA ₂ . A signal is output at a timing earlier by the crank angle corresponding to the invalid injection pulse width Ts.

On the other hand, regarding the first half injection, the above-mentioned steps are performed.
Excessive injection crank angle θ obtained in 24 _ER2Just jet
And further crank angle CA₁To end the injection at
Set the fuel injection start timing to. In addition, in the first half of the injection
Also regarding the above, a clan corresponding to the invalid injection pulse width Ts is obtained.
It is necessary to determine the injection timing in consideration of the
As in the first embodiment, the stroke corresponding to the invalid injection pulse width Ts is
A signal is output to the fuel injection valve 10 at a time when the rank angle is faster.
Be done.

On the other hand, if it is determined in step 25 that the excessive injection crank angle θ _ER2 > 0 is not satisfied (NO), it is determined that the injection crank angle θ is smaller than the first half maximum angle θ _MAX2 , and the process proceeds to step 27. In step 27, the injection crank angle θ
No division setting is performed and the first half injection is not performed. And
Regarding the latter half of the injection, a signal is output to the fuel injection valve 10 so as to end the injection at the crank angle CA ₃ , and the injection is performed by the injection crank angle θ to end the injection. As described above, the fuel injection pulse width Ti is
Since the invalid injection pulse width Ts is included, the fuel injection valve
At 10, the fuel injection valve advances by the invalid injection pulse width Ts.
The signal is output to 10.

In step 28, the steps 26 or 27 are executed.
The injection crank angle θ set in step 1 is converted into the corresponding injection pulse time width again, and the injection pulse signal is converted to the fuel injection valve 10
Output to. Therefore, in the second embodiment, as shown in FIG. 7, the fuel injection related to the latter half of the injection ends at the crank angle CA ₃ after the crank angle CA _{EN at which} the lift of the intake valve ends and the injection amount Ti increases. Therefore, the maximum is
Up to a crank angle CA ₂ near the crank angle CA _MAX ,
The fuel injection end timing is advanced. When the injection is required to be performed longer than the latter half maximum angle θ _MAX2 , the crank angle C, which is the crank angle at the beginning of the period in which the fuel injection related to the first half injection is also prohibited from the injection control, is performed.
It will be controlled to finish at A ₁ . That is, the injection control of the fuel injection valve 10 is prohibited at the crank angle CA _PR from the crank angle CA ₁ to the crank angle CA ₂ near the crank angle CA _{MAX at} which the intake valves 3 and 4 have the maximum lift. It is possible to prevent the spray injected from the fuel injection valve 10 from coming into contact with the lining of the intake valves 3 and 4. As a result, the combustion properties of the engine, such as the stabilization of combustion and the reduction of smoke and HC, are improved, so that the effects of suppressing the generation of deposits and ensuring the valve sealability can be achieved.

Further, in the second embodiment, since the injection end timing is fixed to the compression stroke and the injection control is controlled so as to be delayed, the stratification of the fuel and air is promoted, and the fuel is diluted. Stable combustion can be obtained even at various air-fuel ratios, and there is also an effect that leads to an improvement in the fuel consumption rate. Further, since the fuel adhering to the intake valve does not enter the combustion chamber in the cycle in which it is injected, but is supplied to the combustion chamber in the next and subsequent cycles, it is possible to prevent fluctuations in the air-fuel ratio in each cycle. There is also the effect.

FIG. 8 shows a third aspect of the invention according to claim 5.
4 shows a flowchart of an embodiment. In step 31, the effective fuel injection amount (effective injection pulse width) Te calculated by the control unit 40 is read. As shown in FIG. 9, the intake valves 3 and 4 have a crank angle C near the intake start top dead center.
The lift is started at A _ST , lifted to the maximum lift L _MAX (the crank angle at that time is CA _MAX ), and then lifted at the crank angle CA _EN near the intake end bottom dead center.

The intake valves 3 and 4 have the maximum lift L._MAXWhen
Crank angle CA_MAXNearby club
Link angle CA₁To crank angle CA₂Between
Link angle CA_PR, The injection control of the fuel injection valve 10 is prohibited.
Stop. Here, in the third embodiment, the controller
Of the fuel injection valve 10 driven and controlled by the fuel unit 40
Regardless of the length of the period, the crank angle CA
_PRIt is configured to be divided by sandwiching. That is, the first half injection
The injection control of the fuel injection valve 10 is prohibited at the fuel injection end timing related to
Crank angle at the latest so that it is before the period to be stopped
CA₁And set the fuel injection start timing for the latter half of the injection.
After the period when the injection control of the fuel injection valve 10 is prohibited
Therefore, at the earliest, the crank angle CA₂And the configuration to set
did.

Further, in the third embodiment, the midpoint of the injection period of the divided fuel injection valve 10 is set to the crank angle C.
Fixed to A _MAX . Therefore, in step 32, step 31
The effective injection pulse width Te read in step 2 is divided into two to calculate the divided injection pulse width Th. In step 33, step 32
The divided fuel injection pulse width Ti ′ (Th + Ts) is calculated by adding the invalid injection pulse width Ts related to the voltage fluctuation of the battery and the like to the divided injection pulse width Th calculated in. Then, regarding the first half injection, a signal is output to the fuel injection valve 10 so that the injection is performed by the divided fuel injection pulse width Ti ′ and the injection ends at the crank angle CA ₁ .

On the other hand, in the latter half of the injection, injection is performed by the divided fuel injection pulse width Ti ', but the crank angle CA
As ₂ enable injection is started, the crank angle CA ₂
A signal is output to the fuel injection valve 10 so that the injection is started at a timing earlier by the crank angle corresponding to the invalid injection pulse width Ts. Therefore, in the third embodiment, as shown in FIG. 9, the crank angle CA at which the intake valves 3 and 4 have the maximum lift.
Crank angle CA ₁ to crank angle CA ₂ near _MAX
Up to the crank angle CA _PR , the injection control of the fuel injection valve 10 is prohibited, and it is possible to prevent the spray injected from the fuel injection valve 10 from coming into contact with the umbrella backs of the intake valves 3 and 4. As a result, the combustion properties of the engine, such as the stabilization of combustion and the reduction of smoke and HC, are improved, so that the effects of suppressing the generation of deposits and ensuring the valve sealability can be achieved.

Further, in the third embodiment, since the fuel is divided into two parts and most of the fuel is supplied in the intake stroke, the fuel is widely dispersed in the intake air, and the local air-fuel ratio is high. There is also an effect that the generation of the region is suppressed, soot generation and unburned fuel discharge are reduced.

[0047]

As described above, according to the first aspect of the present invention, when the intake valve lift is near the maximum, the injection control of the fuel injection valve is prohibited, so that the intake valve has the maximum lift. When it becomes, it is possible to prevent the spray injected from the injection valve from abutting against the intake valve, preventing the fuel from hitting the back of the intake valve and ensuring stable combustion. effective.

According to the second aspect of the invention, when the injection period of the fuel injection valve is longer than a predetermined period, the injection period is divided, and the injection control for the fuel injection related to the first half injection is prohibited. The fuel injection related to the latter half of the injection is ended before the period, and the fuel injection related to the latter half of the injection is started after the period in which the injection control is prohibited. When the intake valve reaches the maximum lift, the spray injected from the injection valve is the intake valve. Since it is possible to prevent the fuel from hitting the inner surface of the intake valve, it is possible to ensure stable combustion.

Further, in the third aspect of the invention, the fuel injection related to the first half injection is started at a predetermined time immediately after the intake valve lift is started, and the fuel injection end timing is accompanied by an increase in the injection amount. Is delayed. Further, the fuel injection related to the latter half of the injection is also started at a predetermined timing immediately after the period when the injection control is prohibited. Therefore, even in the medium load region where the injection period is long, smoke and HC do not increase and the deposit is generated and the valve is This has the effect of preventing the occurrence of sealing defects and the like.

In addition, according to the invention described in claim 4, the same effects as described above are obtained, and further, since the injection control is controlled to be delayed, the stratification of fuel and air is performed. There is also an effect that it is promoted and stable combustion is obtained even with a lean air-fuel ratio. Further, according to the invention described in claim 5, it goes without saying that the same effect as described above can be obtained.
Further, even if the injection amount is small, it is surely dispersed and injected, and there is also an effect that a good air-fuel mixture is formed in the combustion chamber.

Further, according to the invention described in claim 6, the same effect as described above can be obtained in an internal combustion engine having two intake valves for each cylinder. According to the invention described in claim 7, the same effect as described above can be obtained even in the internal combustion engine in which the intake port is provided with a plurality of intake valves.

[Brief description of drawings]

FIG. 1 is a block diagram showing the basic configuration of the present invention.

FIG. 2 is a schematic sectional view of the system of the embodiment.

FIG. 3 is a schematic plan view of the system of the embodiment.

FIG. 4 is a flowchart showing the control contents of the first embodiment of the present invention.

FIG. 5 is a characteristic diagram for explaining the operation of the first embodiment.

FIG. 6 is a flowchart showing the control contents of the second embodiment of the present invention.

FIG. 7 is a characteristic diagram for explaining the operation of the second embodiment.

FIG. 8 is a flowchart showing the control contents of the third embodiment of the present invention.

FIG. 9 is a characteristic diagram for explaining the operation of the third embodiment.

[Explanation of symbols]

 1 engine 2 cylinder 3 intake valve 4 intake valve 8 intake port 9 intake port 10 fuel injection valve 40 control unit 42 crank angle sensor

Claims (7)

[Claims] 1. At least one intake valve provided for each cylinder, a fuel injection valve for injecting fuel into each cylinder toward the vicinity of the rear surface of the intake valve, and a fuel injection valve based on engine operating conditions. Fuel injection control means for calculating a fuel injection amount to be injected and controlling a fuel injection valve according to the fuel injection amount between a predetermined injection start timing and a predetermined injection end timing; In the timing control device, if the intake valve lift detection means for detecting lift of the intake valve and the intake valve lift detected by the intake valve lift detection means are in the vicinity of the maximum, the fuel injection valve by the fuel injection control means A fuel injection timing control device for an internal combustion engine, comprising: 2. When the injection period of the fuel injection valve driven and controlled by the fuel injection control unit is longer than a predetermined period, the injection period is divided and the fuel injection end timing relating to the first half injection is prohibited by the prohibition unit. 2. The internal combustion engine according to claim 1, wherein the injection control is set before the period when the injection control is prohibited, and the fuel injection start timing for the latter half injection is set after the period when the injection control is prohibited by the prohibiting means. Fuel injection timing control device. 3. When the injection period of the fuel injection valve driven and controlled by the fuel injection control means is longer than a predetermined period, the injection period is divided and the fuel injection start timing relating to the first half injection is set to the intake valve lift. The intake valve lift detected by the detection means is fixed to a predetermined timing immediately after the start of the lift, the fuel injection end timing is delayed as the injection amount increases, and the fuel injection start timing relating to the latter half injection is prohibited. The fuel injection timing control device for an internal combustion engine according to claim 1 or 2, wherein the fuel injection timing control device is fixed at a predetermined time immediately after the period when the injection control is prohibited by. 4. When the injection period of the fuel injection valve driven and controlled by the fuel injection control means is longer than a predetermined period, the injection period is divided and the fuel injection end timing relating to the latter half injection is set to the intake valve lift. It is fixed at a predetermined time after the lift of the intake valve detected by the detection means is ended, the fuel injection start timing is advanced with an increase in the injection amount, and the fuel injection end timing relating to the first half injection is prohibited by the prohibition means. The fuel injection timing control device for an internal combustion engine according to claim 1 or 2, wherein the fuel injection timing control device is fixed at a predetermined time immediately before a period in which the injection control is prohibited. 5. An injection period of a fuel injection valve drive-controlled by a fuel injection control unit is divided, and a midpoint of the divided injection period is fixed to a period in which injection control is prohibited by a prohibition unit. The fuel injection timing control device for an internal combustion engine according to claim 1 or 2. 6. The fuel injection timing control device for an internal combustion engine according to claim 1, wherein each cylinder has two intake valves. 7. A plurality of intake valves and a plurality of intake ports branching from the middle of the intake passage to reach the intake valves are provided for each cylinder, and the intake passages on the upstream side of the branch portions of the intake ports are provided. 7. The fuel injection timing control device for an internal combustion engine according to claim 1, further comprising a fuel injection valve that simultaneously injects fuel in a plurality of directions toward the intake port.