JP2001159322A - Intake device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure stability and improve fuel consumption while carrying out the generation of seating noises of an intake valve, reduction of a consumption power, and improvement of durability, in an engine provided at each cylinder with two electromagnetically driven suction valves. SOLUTION: Fuel injection valves 7A and 7B are mounted on intake ports 5A and 5B, respectively. On a given operation condition that an intake air quantity is high enough to allow opening of one suction valve, suction valves 3A and 3B are alternately opened at intervals of a given time and fuel is injected through only a fuel injection valve 7A or 7B corresponding to the suction valve brought into an opening state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine provided with an electromagnetically driven intake valve whose opening and closing timing can be freely controlled, in which the seating sound of the intake valve, the power consumption is reduced, and the durability is improved. About.

[0002]

2. Description of the Related Art In order to improve intake characteristics, there has been proposed an electromagnetically driven intake valve having two freely controllable opening and closing timings for each cylinder (Japanese Patent Laid-Open No. 7-102982). See).

[0003]

The electromagnetically driven intake valve generates a large amount of noise due to electromagnetic attraction and consumes electric power. For this reason, in the low / medium speed to low / medium load region where the intake air amount can be covered by one intake valve, the operation of one intake valve for each cylinder is stopped to operate, thereby reducing the noise and consumption of the intake valve. It was conceived to reduce the power and improve the durability.

[0004] However, in response to the demand under high load, the
Since two fuel injection valves simultaneously inject fuel into two intake ports, if only one of the intake valves is continuously stopped, fuel will be accumulated behind the stopped intake valve. For this reason, only one of the two intake valves is alternately opened for each fuel injection,
By shutting down the other, the fuel pool is reduced to one.
Although it can be limited to batches, the influence of the distribution variation of the fuel injection amount to the two intake ports is doubled.
For example, assuming that the fuel amount injected toward the two intake ports is 45 and 55 and the total is 100, when one of the intake valves is opened, the fuel amount 45 injected this time and the intake amount 90 with the amount of fuel accumulated in the port
Is supplied to the cylinder, and when the other intake valve is opened, a total of 110 fuel amounts of the 55 currently injected amount and the 55 previously injected amount are similarly supplied. , 90 and 110 are supplied alternately. As described above, since the amount of fuel supplied in each cycle varies greatly, the stability of the engine varies in each cycle, and the stability deteriorates.

[0005] The fuel is distributed to the two intake ports using the fuel injection valve which is previously injected in two directions toward the two intake ports as described above. There is also a method of separating fuel by injecting fuel toward a branch wall between two intake ports by using a fuel injection valve that injects fuel. However, in this method, there is a variation in distribution of an injection amount to two intake ports. Is further increased, and the operation state such as intake pulsation is greatly affected.

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and suppresses a variation in the amount of fuel supplied alternately from two intake ports for each cylinder under a predetermined operating condition while suppressing electromagnetic fluctuation. It is an object of the present invention to provide an intake device for an internal combustion engine that can reduce seating noise and power consumption of a drive-type intake valve, improve durability, and improve fuel efficiency by improving stability.

[0007]

For this reason, the invention according to claim 1 is provided with two intake ports for each cylinder, and each of the intake ports is provided with an electromagnetically driven intake valve capable of freely controlling the opening and closing timing. In the engine provided, a fuel injection valve is provided for each intake port, and only one of the intake valves of two intake ports is alternately opened under a predetermined operating condition.

According to the first aspect of the present invention, under predetermined operating conditions such as a low / medium speed to low / medium load region where the intake air amount can be covered by opening one intake valve, two cylinders per cylinder are required. By alternately opening only one of the electromagnetically driven intake valves, the seating noise and power consumption can be reduced by half, and the durability of the intake valve can be improved.

On the other hand, the variation in the fuel injection amount characteristic of each product of the fuel injection valve provided in each of the two intake ports is compared with the distribution variation of the fuel injection amount to the two intake ports of each fuel injection valve. Therefore, the distribution of the fuel injection amount from each fuel injection valve to the two intake ports can be kept sufficiently small. This allows
Variations in the amount of fuel supplied from the intake ports to the cylinders alternately via the intake valves can be suppressed, and the stability of the engine can be improved, and the ignition timing is advanced by the improved stability to improve fuel efficiency. Can be.

The invention according to claim 2 is characterized in that the intake valves of the two intake ports alternately open at predetermined time intervals under the predetermined operating conditions.

According to the second aspect of the present invention, it is possible to alternately open the two intake valves for each fuel injection of each cylinder. In this case, the direction of intake air into the cylinder is changed each time. Is changed, and the swirl generated successively is canceled out, so that it is difficult to obtain a stable swirl. Under operating conditions where the intake air amount is small when the intake valves are alternately opened, it is required to improve the mixability between fuel and air by swirling.

Therefore, by opening the two intake valves alternately at predetermined time intervals, the intake air is allowed to flow continuously from the same intake port for a predetermined time to generate a stable swirl, thereby achieving good combustion. Ensure performance.

The invention according to claim 3 is characterized in that the intake valves of the two intake ports alternately open each time the predetermined operating condition is satisfied.

According to the third aspect of the invention, the intake valves of the two intake ports alternately open each time a predetermined operating condition is satisfied for the same reason as described in the second aspect. As a result, while the predetermined operating conditions continue to be satisfied, the intake air is continuously flowed in from the same intake port to generate a stable swirl so that good combustion performance can be secured.

Further, the invention according to claim 4 is characterized in that fuel is injected only from a fuel injection valve mounted on an intake port whose intake valve is open.

According to the fourth aspect of the invention, when two intake valves are alternately opened for each fuel injection of each cylinder,
Although it is possible to inject two fuel injection valves at the same time and to supply the cylinder with the sum of the current injection fuel amount and the previous injection fuel amount to the cylinder, it is still possible to collect one fuel in the intake port. Is generated.

According to a second aspect, a certain period,
When supplying fuel from only one intake port, simultaneous injection of two fuel injection valves causes a large amount of fuel to accumulate in the other intake port, making it substantially impossible to supply fuel stably. .

Therefore, by injecting fuel only from the fuel injection valve attached to one of the intake ports where the intake valve is open, and stopping the fuel injection from the other fuel injection valve, the other intake valve is stopped. It is possible to prevent the accumulation of fuel in the port and obtain a stable fuel supply.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 showing one embodiment, an engine 1 has two intake valves 3A,
3B and exhaust valves 4A and 4B, and corresponding intake ports 5A and 5B and exhaust ports 6A and 6B.
The opening and closing of the intake valves 3A and 3B and the exhaust valves 4A and 4B are electronically controlled by a valve driving device 2. Here, the valve drive device 2 is configured to be able to independently control the opening and closing of at least two intake valves 3A and 3B.

On the other hand, the two intake ports 5A, 5B
, Fuel injection valves 7A and 7B of the same standard are mounted. As the fuel injection valves 7A and 7B, any of the above-described two-way fuel injection and one-way fuel injection may be used, but the fuel injected from each of the fuel injection valves 7A and 7B may be used. The mounting position and the direction are set so that the entire amount is supplied to the corresponding intake ports 5A and 5B without being affected by the operation state such as the intake pulsation.

An ignition plug 9 and an ignition coil 10 are mounted in the combustion chamber 8. The engine body outputs a reference signal at the reference crank angle of each cylinder, outputs a unit angle signal for each minute crank angle, a crank angle sensor 11, an air flow meter 12 for detecting intake air flow rate, and a cooling water temperature. A water temperature sensor 13 to be detected is mounted. Is installed.

The signals from the various sensors are output to a control unit 14. The control unit 14 outputs a fuel injection signal to the fuel injection valve 7 based on these detection signals to perform fuel injection control, and Coil 10
To control the opening and closing of the intake valves 3A and 3B and the exhaust valves 4A and 4B by outputting a valve drive signal to the valve drive device 2.

FIG. 3 shows the structure of the valve driving device 2. In FIG. 3, a valve driving device 2 includes a housing 21 made of a non-magnetic material provided on a cylinder head, and intake valves 3A and 3B.
(Or exhaust valves 4A, 4B, hereinafter represented by intake valves 3A)
An armature 22 provided integrally with the stem 31 and freely housed in the housing 21, and an upper surface of the armature 22 so as to exert an electromagnetic force for sucking the armature 22 and closing the intake valve 3A. A valve-closing electromagnet 23 fixedly disposed in the housing 21 at a position facing the armature 22 and a lower surface of the armature 22 so as to exert an electromagnetic force for attracting the armature 22 and opening the intake valve 3A. Valve-opening electromagnet 24 fixedly arranged in the housing 21 at the position
A valve-closing-side return spring 25 that urges the armature 22 toward the valve closing direction of the intake valve 3A, a valve-opening-side return spring 26 that urges the armature 22 toward the valve opening direction of the intake valve 3A, It is comprised including. Then, when the valve closing electromagnet 23 and the valve opening electromagnet 24 are both demagnetized, the intake valve 3A and the valve closing-side return spring 25 are positioned so that the intake valve 3A is substantially at the center between the fully open position and the valve closed position. The spring force with the valve-opening return spring 26 is set, and the intake valve 3A is closed when only the valve-closing electromagnet 23 is excited, and the intake valve 3A is opened when only the valve-opening electromagnet 24 is excited. (Fully open).

Intake valves 3A, 3B by the valve drive device 2
The opening / closing timing of the exhaust valves 4A, 4B is controlled to be a set target opening / closing timing such that a desired intake air amount is obtained based on the operating state of the engine 1.

Next, the control of the intake valves 3A, 3B and the fuel injection valves 7A, 7B under predetermined operating conditions according to the present invention will be described.
This will be described with reference to the flowcharts of FIGS. FIG.
Shows a routine for setting a flag for switching the control of the intake valves 3A, 3B and the fuel injection valves 7A, 7B according to operating conditions.

In step 1, it is determined whether or not the intake air amount is a predetermined operating condition such as a low / medium speed to low / medium load region that can be covered by one intake valve. When it is determined in step 1 that the predetermined operating condition is satisfied, the process proceeds to step 2, and it is determined whether or not the first time the determination is made. The flag FKA is set to 1 so as to open only the valve 3A, and the flag FKB is stopped so as to stop the valve opening operation of the other intake valve 3B.
Is reset to 0, the flag FNA is set to 1 so that only the fuel injection valve 7A attached to the one intake port 5A to which the intake valve 3A is attached is operated for fuel injection, and the other fuel injection valve 7B The flag FNB is reset to 0 so as to stop the fuel injection operation.

[0027] If it is determined that the predetermined operating condition is satisfied,
After the first time, the process proceeds to step 4, and the current one intake valve 3A
It is determined whether only the valve opening operation is performed based on whether the flag FKA is set to 1.

If it is determined that the flag FKA is set to 1, the routine proceeds to step 5, where it is determined whether or not this state has continued beyond a predetermined time T. Then, the current state is maintained when the time is within the predetermined time T, but if it is determined that the operation has continued beyond the predetermined time T, the process proceeds to step 6 so that only the other intake valve 3B is opened. The flag FKB is set to 1 and the flag FKA is reset to 0 so as to stop the opening operation of the intake valve 3A.
The other intake port 5 to which the other intake valve 3B is mounted.
The flag FNB is set to 1 so that only the fuel injection valve 7B attached to B performs the fuel injection operation, and the flag FNA is reset to 0 so that the fuel injection operation of the fuel injection valve 7A is stopped.

In step 4, the flag FKA is set to 0.
Is set, that is, when it is determined that the other intake valve 3B is performing the valve-opening operation, the process proceeds to step 7, and it is determined whether this state has continued for a predetermined time T or more. If it is within the time T, the current state is maintained, but if it is determined that the time has continued beyond the predetermined time T, step 8
To set the flag FKA to 1 and set the flag FKB to 0
In addition, the flag FNA is set to 1 and the flag FNB is reset to 0, and switching is performed so that the valve opening operation of only the intake valve 3A and the fuel injection operation of only the fuel injection valve 5A are performed.

If it is determined in step 1 that the predetermined operating condition is not satisfied, the routine proceeds to step 9, in which the two intake valves 3A and 3B are both opened and the two fuel injection valves 7A are operated. , 7B for the fuel injection operation together,
The flags FKA, FKB, FNA, and FNB are all set to 1.

FIG. 5 shows a control routine of the intake valve. In step 11, the values of the flags FKA and FKB are read.
In step 12, it is determined whether it is the valve opening timing of the intake valve. If it is determined that the valve opening timing is reached, the process proceeds to step 13, and the intake valve is opened according to the values of the flags FKA and FKB.
That is, when only one of the flags FKA and FKB is 1 and the other is 0, only the intake valve 3A or the intake valve 3B is opened, and when both the flags FKA and FKB are 1, the intake valve is opened. 3A and 3B are simultaneously opened.

In step 14, it is determined whether or not it is time to close the intake valve. If it is determined that the valve is to be closed, the routine proceeds to step 15, where the opened intake valve is closed. FIG. 6 shows a control routine of the fuel injection valve.

In step 21, the values of the flags FNA and FNB are read. In step 22, it is determined whether it is the fuel injection start timing. If it is determined that the fuel injection start timing is reached, the process proceeds to step 23, and the fuel injection valve is opened according to the values of the flags FNA and FNB. That is, when the flag FNA is 1,
When only one of the FNBs is 1 and the other is 0, only the fuel injection valve 7A or the fuel injection valve 7B is opened to perform the fuel injection operation. When both the flags FNA and FNB are 1, the fuel injection valve 7A and 7B are simultaneously opened.

In step 24, it is determined whether it is the fuel injection end timing. If it is determined that the fuel injection end timing is reached, the routine proceeds to step 25, where the fuel injection valve which has been opened is closed to terminate the fuel injection. I do.

Here, when the two fuel injection valves 7A and 7B are simultaneously opened, the set fuel injection amount (injection pulse) is set as compared with the case where one fuel injection valve 5A or 5B is opened. The width of each fuel injection valve corresponding to the width is controlled to be 各, and fuel is injected half by half from each fuel injection valve.

With the above configuration, under predetermined operating conditions such as a low / medium speed to low / medium load region where the intake air amount can be covered by opening one intake valve, two cylinders per cylinder are required. By alternately opening only one of the intake valves, the seating sound,
The power consumption can be reduced by half, and the durability of the intake valve can be improved.

The variation in the distribution of the amount of fuel injected from the two fuel injection valves for each cylinder to each intake port is determined by the product variation of these fuel injection valves, and can be kept sufficiently small.
As a result, it is possible to suppress a variation in the amount of fuel that is alternately supplied to the cylinder from each intake port via the intake valve, thereby improving the stability of the engine and, as shown in FIG. Can be advanced to improve fuel efficiency.

Also, by alternately opening the two intake valves at predetermined time intervals, the intake air is allowed to flow continuously from the same intake port for a predetermined time to generate a stable swirl, thereby achieving good combustion. Performance can be secured.

FIG. 8 shows an intake valve 3 according to the second embodiment.
4 shows a routine for setting a flag for switching control of the fuel injection valves A, 3B and the fuel injection valves 7A, 7B in accordance with operating conditions. In step 31, it is determined whether or not the intake air amount is a predetermined operating condition such as a low / medium speed to low / medium load region that can be covered by one intake valve.

When it is determined in step 31 that the predetermined operating condition is satisfied, the process proceeds to step 32, in which it is determined whether or not the determination is the first time.
To the intake valves 3A and 3B when the predetermined operating conditions are satisfied last time.
Are opened, and the fuel injection valve 7 is correspondingly operated.
Which of A and 7B has been subjected to the fuel injection operation is determined based on the value of the flag F stored last time. Where, for example,
When the flag F is set to 1, the previous intake valve 3A
Is opened, the fuel injection valve 7A is operated for fuel injection,
When the flag F is reset to 0, the last intake valve 3
It is assumed that B is operated to open and the fuel injection valve 7B is operated to inject fuel.

If it is determined in step 33 that the flag F is set to 1, the routine proceeds to step 34, where the flag F is set.
Are reset to 0 and the flags FKA = 0, FK are set so that only the intake valve 3B is opened and only the fuel injection valve 7B is operated for fuel injection when the predetermined operating conditions are satisfied this time.
B = 1, FNA = 0, and FNB = 1 are set.

If it is determined in step 33 that the flag F has been reset to 0, the routine proceeds to step 35, in which the flag F is set to 1 and only the intake valve 3A when the predetermined operating conditions are satisfied. Is operated so that only the fuel injection valve 7A is operated for fuel injection.
1, FKB = 0, FNA = 1, and FNB = 0.

The current condition is maintained for the second and subsequent times after the predetermined operating conditions are continuously established. If it is determined in step 31 that the predetermined operating condition is not satisfied, the process proceeds to step 36, in which the two intake valves 3A and 3B are both opened, and the two fuel injection valves 7A and 7B are opened. To perform the fuel injection operation, the flags FKA, FKB, FNA, FNB
Are all set to 1.

The control of the intake valve and the control of the fuel injection valve are similarly controlled in accordance with FIGS. In the present embodiment, every time a predetermined operating condition is satisfied, the intake valve and the fuel injection valve are operated alternately so as to operate differently from the last time, so that the predetermined operating condition is continuously satisfied. During this period, the intake air can be continuously supplied from the same intake port to generate a stable swirl, thereby ensuring good combustion performance.

However, for example, in the case where the fuel and the air can be sufficiently mixed by a method other than swirl, two intake valves for each cylinder are opened alternately for each fuel injection. The valve may be configured to operate, in which case,
As a configuration in which two fuel injection valves simultaneously inject fuel by an equal amount, a configuration may be adopted in which the total amount of fuel injected this time and fuel previously injected and accumulated in the intake port is supplied to the cylinder.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram according to an embodiment.

FIG. 2 is a partial cross-sectional view of the same system configuration diagram.

FIG. 3 is a sectional view showing the configuration of the valve drive device according to the embodiment;

FIG. 4 is a flowchart illustrating a flag setting routine for intake valve opening control and fuel injection control according to the first embodiment;

FIG. 5 is a flowchart illustrating an intake valve opening control routine according to the first embodiment;

FIG. 6 is a flowchart illustrating a fuel injection control routine according to the first embodiment.

FIG. 7 is a flowchart illustrating a flag setting routine for intake valve opening control and fuel injection control according to a second embodiment.

FIG. 8 is a diagram showing the effect of the present invention in comparison with a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Valve drive 3A, 3B Intake valve 5A, 5B Intake port 7A, 7B Fuel injection valve 14 Control unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02B 31/02 F02B 31/02 H F02D 43/00 301 F02D 43/00 301J 301Z 45/00 366 45/00 366Z F02M 35/108 F02M 69/00 360G 69/00 360 35/10 301B

Claims (4)

[Claims] 1. An engine provided with two intake ports for each cylinder and an electromagnetically driven intake valve capable of freely controlling the opening / closing timing of each intake port, wherein a fuel injection valve is provided for each intake port. An intake device for an engine, wherein the intake valves of the two intake ports are alternately opened under predetermined operating conditions. 2. The intake system for an engine according to claim 1, wherein the intake valves of the two intake ports alternately open at predetermined time intervals under the predetermined operating conditions. 3. The intake system for an engine according to claim 1, wherein the intake valves of the two intake ports alternately open each time the predetermined operating condition is satisfied. 4. The engine according to claim 1, wherein fuel is injected only from a fuel injection valve mounted on an intake port whose intake valve is open. Intake device.