JPH1130132A - Multi-cylinder engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-cylinder engine in which fluctuation of the rotational speed can be eliminated. SOLUTION: In a multi-cylinder engine, which cylinder generates fluctuation of the rotational speed of a crankshaft 18 is judged from signals of a crank angle sensor 21 and a cam angle sensor 24 by an ECU 60, and the intake air amount is adjusted by adjusting the opening of an electrically-controlled throttle valve 40 related to the cylinder, in electrically-controlled throttle valves 40 provided for each cylinder in an intake pipe or for each bank part according to the fluctuation amount of the rotational speed. Combustion is stabilized by adjusting the fuel injection amount by an injector 42 of the cylinder according to the adjusting amount of the intake air amount, and fluctuation of the rotational speed of the crankshaft 18 is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine, and more particularly to a multi-cylinder engine mounted on an automobile or the like.

[0002]

2. Description of the Related Art In a general multi-cylinder engine, combustion control for each cylinder is uniformly performed by opening and closing one throttle valve provided in the middle of an intake passage to adjust an intake air amount. . Here, the compression ratio of the engine is generally determined by the volume of the combustion chamber of the cylinder head, but since the cylinder head is formed by casting compared to a piston manufactured with high precision by machining, the combustion chamber is a cylinder. Each volume has a slightly different volume. Therefore, the compression ratio of each cylinder has a slight variation with respect to the design value. Further, in addition to the above-described variations, the variations in the thickness of the suction pipe and the diameter of the tip hole of the injector that injects fuel are superimposed, so that the combustion state differs for each cylinder. As a result, the rotation speed of the crankshaft that is rotationally driven by combining the operation of the engines in each cylinder fluctuates (hereinafter, referred to as “rotation fluctuation”).
Occurs. In particular, if there is a cylinder having a large difference in combustion state during idling operation, vibration and noise due to the above-mentioned rotation fluctuation are transmitted to the driver, and there is a problem that comfort is impaired.

Therefore, an engine is provided with a throttle valve (hereinafter referred to as an "electronically controlled throttle valve") which is independently controlled for each cylinder at a predetermined position of an intake pipe to regulate the combustion state of each cylinder and suppress rotation fluctuation. Are known. In addition, this engine has the advantage of being generally responsive and suitable for producing high power. However, in an operation state in a low load region including an idling operation, the intake air amount for each cylinder is small, and a slight difference in an opening area due to an error due to manufacturing, processing, or combination of the intake pipe and the throttle valve is likely to be affected. Therefore, the problem that the intake air amount varies for each cylinder and the idling rotation becomes unstable cannot be solved.

In order to eliminate this instability, a balance tube is provided across the intake pipe at a position downstream of the electronically controlled throttle valve in each cylinder to stabilize idle rotation by making the distribution of intake air uniform for each cylinder. Is known. In the method disclosed in Japanese Patent Laid-Open No. 5-79359, an independent throttle valve is provided for each cylinder, and another throttle valve is provided in an intake passage upstream of the cylinder. During idling operation, the variation is made uniform by controlling the amount of intake air to each cylinder mainly by the opening degree of the throttle valve in the intake passage to avoid rotational vibration,
In addition, during high-load operation, the amount of intake air to each cylinder is controlled by the degree of opening of the independent throttle valve for each cylinder,
A method of improving response and obtaining a large output is known.

[0005]

However, in the above-described rotation stabilization by the balance tube, the intake of the intake air to the respective cylinders is performed substantially equally at the time of idling or the like due to the effect of the balance tube. Increasing the path diameter impairs good response and loses its meaning as an independent throttle valve.Conversely, if the path diameter of the balance tube is reduced, the balance function is weakened and rotation at low load becomes unstable. Become. Therefore, it is difficult to sufficiently balance the rotation between the cylinders while maintaining a good response.

In the method disclosed in Japanese Patent Application Laid-Open No. 5-79359, in which another throttle valve is provided upstream, the rotation of the engine is stabilized only by controlling the amount of intake air. No control. Therefore, the air-fuel ratio is changed, and in some cases, the combustion state deteriorates and the components of the exhaust gas are biased.
Another problem occurs that C is discharged into the atmosphere. Further, in this device, since the throttle valve is arranged in a double manner, the control method becomes complicated.

[0007] The present invention has been made in view of the above points, and an object thereof is to provide a multi-cylinder engine capable of stabilizing rotation.

[0008]

In order to achieve the above object, the present invention comprises a multi-cylinder engine described below as means thereof. That is, in the multi-cylinder engine according to claim 1, an injector provided in the intake pipe for each cylinder and injecting fuel toward the combustion chamber side of the engine, a crankshaft that is rotationally driven by power generated in each cylinder, And a crankshaft rotation speed detecting means for detecting the rotation speed of the crankshaft. The throttle valve is provided so that the opening can be adjusted so as to adjust the amount of air taken into the combustion chamber for each cylinder in the intake pipe, and the cylinder discrimination for discriminating which cylinder is driven by the rotational speed of the crankshaft. Means and a signal from the cylinder discriminating means, and a signal from the crankshaft rotational speed detecting means. And a rotational speed control means for adjusting the fuel injection amount by the injector of each cylinder for each cylinder in accordance with the adjustment of the intake air amount.

According to the multi-cylinder engine having such a configuration, even if the rotation of the crankshaft fluctuates, the cylinder causing the fluctuation is determined without destroying the target air-fuel ratio, and the combustion in the cylinder is determined. Since the state is improved and the rotation fluctuation is eliminated, it is possible to stabilize the engine rotation.

Next, in the multi-cylinder engine according to the second aspect, the rotational speed control means according to the first aspect controls the power of each cylinder based on signals from the cylinder discriminating means and the crankshaft rotational speed detecting means. Open the throttle valve of the cylinder whose rotational speed is decreasing the most, and increase the intake air amount according to the amount of change in the rotational speed due to the difference in the intake air amount. The fuel injection amount is increasing.

According to the multi-cylinder engine having such a configuration, even if there is a fluctuation in the rotation of the crankshaft, the rotation speed is reduced, the cylinder having the large fluctuation is determined, and the target air-fuel ratio is destroyed. Since the combustion state is improved without any problem, it is possible to stabilize the engine rotation by eliminating the rotation fluctuation.

In the multi-cylinder engine according to the third aspect, the rotational speed control means according to the second aspect controls the increase of the intake air amount and the fuel injection amount of the cylinder whose rotational speed is most reduced. In addition, close the throttle valve of the cylinder that is increasing the rotation speed the most to reduce the intake air volume,
The fuel injection amount by the injector of the cylinder is reduced in accordance with the decrease in the intake air amount.

According to the multi-cylinder engine having such a configuration, even if the rotational fluctuation of the crankshaft is slight, the cylinder whose rotational speed is most reduced without destroying the target air-fuel ratio, and conversely the rotational speed Is determined and the combustion state in each cylinder is adjusted, so that rotation fluctuations can be eliminated and engine rotation can be stabilized.

Further, in the multi-cylinder engine according to the fourth aspect, an injector provided in the intake pipe for each cylinder to inject fuel toward the combustion chamber side of the engine, and a crank rotatably driven by the power generated in each cylinder. The engine includes a shaft, a crankshaft rotation speed detecting means for detecting a rotation speed of the crankshaft, and a bank portion which is an upstream branch portion in which an intake pipe is divided for each cylinder. And
A throttle valve provided with an adjustable opening to adjust the amount of air taken into the combustion chamber for each bank portion in the intake pipe, and cylinder discriminating means for discriminating which cylinder's rotational speed is due to the motion of the crankshaft. In addition to the signal from the cylinder discriminating means, based on the signal from the crankshaft rotational speed detecting means, the throttle valve of each bank is opened and closed according to the fluctuation amount of the rotation speed caused by the difference in the generated power for each cylinder. To adjust the intake air volume,
Rotational speed control means for adjusting the fuel injection amount by the injector of each bank portion for each cylinder in accordance with the adjustment of the intake air amount.

According to the multi-cylinder engine having the above-described structure, even if the rotation of the crankshaft fluctuates, the cylinder causing the fluctuation is discriminated without deteriorating the target air-fuel ratio, and each bank is provided with a different air-fuel ratio. Since the combustion state is improved and the rotation fluctuation is eliminated, the engine rotation can be stabilized.

Next, in the multi-cylinder engine according to a fifth aspect, the rotational speed control means according to the fourth aspect generates a signal for each cylinder based on signals from the cylinder discriminating means and the crankshaft rotational speed detecting means. According to the fluctuation amount of the rotation speed caused by the difference in the power, the throttle valve provided in the bank portion having the cylinder whose rotation speed is reduced most is opened to increase the intake air amount, and the increase amount of the intake air amount is increased. Accordingly, the fuel injection amount by the injector in the bank is increased.

According to the multi-cylinder engine having such a configuration, even if there is a fluctuation in the rotation of the shaft, the rotation speed is reduced, the cylinder having the large fluctuation amount is determined, and the target air-fuel ratio is destroyed. Since the combustion state is improved without any change, it is possible to stabilize the engine rotation by eliminating the rotation fluctuation.

Finally, in the multi-cylinder engine according to the sixth aspect, the rotational speed control means according to the fifth aspect controls the intake air amount and the fuel injection amount of the bank portion which minimizes the rotational speed. In addition to the increase, the throttle valve provided in the bank having the cylinder whose rotational speed is increasing the most is closed to reduce the amount of intake air, and in accordance with the decrease in the amount of intake air, the fuel of the injector of the bank is used. The injection amount has been reduced.

According to the multi-cylinder engine having such a configuration, even if the rotational fluctuation of the crankshaft is slight, the cylinder whose rotational speed is reduced most without deteriorating the target air-fuel ratio and, conversely, the rotational speed Is determined and the combustion state of the cylinder in each bank portion is adjusted, so that rotation fluctuation can be eliminated and engine rotation can be stabilized.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a conceptual diagram of the engine and its control system according to the present embodiment. In the present embodiment, a four-cylinder reciprocating engine is illustrated.

The engine body 1 comprises a cylinder block 2 and a cylinder head 4 provided for each cylinder. The combustion chamber 6 of the cylinder head 4 has an intake port 8
And the exhaust port 10 are communicated with each other.
An ignition plug 12 is provided near the inner central portion. An intake valve 14 and an exhaust valve 16 for opening and closing the intake port 8 and the exhaust port 10 are provided at openings of the intake port 8 and the exhaust port 10 on the combustion chamber 4 side, respectively.

The engine body 1 has a crankshaft 1 which is rotationally driven by power generated from combustion of each cylinder.
8, a crank angle sensor 21 for detecting a rotation angle of the crankshaft 18, an intake valve 14, and an exhaust valve 16
And a camshaft 22 for driving the camshaft 2
2 is provided with a cam angle sensor 24 for detecting the rotation angle.

The intake passage 20 on the upstream side of the cylinder head 4
To the intake port 8 from the upstream side, the air cleaner 2
6, air flow meter 28, chamber 30, intake pipe 32
Are sequentially arranged. The intake pipe 32 includes a first-stage branch 34, a bank portion 36, a second-stage branch 38, and an electronically-controlled throttle valve (hereinafter, simply referred to as an "electrically-controlled throttle valve") 40 that is independent for each cylinder in order. Have. Outside air is taken into the combustion chamber 6 via these. The air flow meter 28 detects the amount of air sucked into the engine, and the chamber 30 plays a role as a surge tank for suppressing the pulsation of the sucked air.

The electronically controlled throttle valve 40 is electronically controlled by an ECU 60, which will be described later, which receives a signal from an accelerator pedal depression amount sensor 82 for detecting and outputting the depression amount of an accelerator pedal 80, and its opening is determined. . Therefore, the electronically controlled throttle valve 40 is opened and closed according to the amount of operation of the accelerator pedal 80 by the driver, and the amount of intake air guided to the intake port 8 can be adjusted. The electronically controlled throttle valve 40 is embodied by an electrically driven actuator (not shown) such as a step motor.

At a position near the intake port 8 of the intake pipe 32, an injector 42 is installed inclined to the intake port 8 direction. The injector 42 is also controlled by a signal from an ECU 60 described later, and injects fuel to secure a target air-fuel ratio. As a result, the outside air and the fuel are mixed to generate a mixture, and the intake valve 14 is opened to flow into the combustion chamber 6.

The air-fuel mixture flowing into the combustion chamber 6 is
The engine is driven by the combustion caused by the ignition of 2 and the piston 46 reciprocating, and the crankshaft 18 being rotated by the reciprocating movement. The burned gas is
When the exhaust valve 16 is opened, the exhaust gas is exhausted from the exhaust port 10 through the exhaust passage 48 as exhaust gas.

The signals from the above-mentioned sensors are input to the ECU 60 capable of receiving the signals electrically. As shown in FIG. 3, the ECU 60 includes a CPU 6 serving as a main operation unit.
1, a ROM 62 for storing a control program and preset data, and a RAM 6 for storing data obtained by processing signals from the sensors and data calculated by the CPU 61.
4. A timer 66 for setting and adjusting time, an input interface 68 for inputting signals from various sensors, and a control signal from the CPU 61 for controlling the electronically controlled throttle valve 4.
An output interface 70 for outputting 0 or the like is configured in the form of a microcomputer connected to each other via a bus line 72. With this configuration, the ECU 60
Is capable of grasping the state of the engine based on signals from various sensors, making a judgment based on preset initial data and a logic program, and outputting a control signal to a control target.

Here, the operation of the present embodiment will be described with reference to a flowchart. The routine shown in the flowchart is one of the processes executed by the ECU 60.
This is an interrupt routine for controlling the combustion state of each cylinder at predetermined time intervals.

This will be described below with reference to the flowchart shown in FIG. The ECU 60 starts this interrupt routine at predetermined time intervals, and reaches step (hereinafter simply referred to as “S”) 100. In S100, it is determined as a premise whether or not the engine is performing a steady operation. This is performed by confirming the rotation state of the engine based on the signal of the crank angle sensor 21. If the engine is not operating in a steady state, this routine ends. If the engine is operating in a steady state, the process proceeds to the next step, S101. In S101,
The rotational speed of the crankshaft 18 is confirmed by calculating the angular velocity between predetermined crank angles from the signal of the crank angle sensor 21.

The confirmation of the rotational speed is performed until at least the movement of all the cylinders in the series is completed, and the average rotational speed of the crankshaft 18 is calculated. Then, as shown in FIG. 2, the fluctuation amount of the rotation speed at each time with respect to the average rotation speed is confirmed. The fluctuation amount of the rotation speed is caused by a difference in power obtained by combustion of each cylinder. Therefore, the ECU 60 executes S102, and determines the cylinder that has generated the rotational speed that has decreased most from the data on the amount of fluctuation of the rotational speed that has been confirmed. This determination is made by using the cam angle sensor 24 as cylinder discriminating means because the combustion timing for each cylinder can be confirmed from the operation timing of the camshaft 22 that determines the intake and exhaust timing for each cylinder.

Here, the decrease in the rotational speed tends to occur due to the deterioration of the combustion state of the cylinder. Therefore, for the cylinder whose combustion state has deteriorated, the intake air amount is increased, and the fuel injection amount is further increased so as not to change the target air-fuel ratio. Therefore, in S103, the ECU 60 outputs a control signal to the electronically controlled throttle valve 40 of the cylinder determined to have the lowest rotational speed to drive the throttle opening to the opening side by Δth. This Δth
Is the opening of the electronically controlled throttle valve 40 corresponding to the increase in the intake air amount for stably performing the motion by combustion taking into account the characteristics of the determined cylinder. It can be obtained by previously obtaining and giving a relational expression between the rotation speed of the crankshaft 18 in the ROM 62 and the opening of the electronically controlled throttle valve 40.
When the electronically controlled throttle valve 40 is opened by a predetermined amount by this signal output, the total intake air amount increases by that amount.
Since the air flow meter 28 installed upstream can detect the increase, a signal is sent to the ECU 60 to confirm the above control.

After adjusting the opening of the electronically controlled throttle valve 40,
In the next step, S104, the ECU 60 determines whether or not the injector 42 of the cylinder that has generated the rotational speed that has decreased the least.
On the other hand, a signal for correction control for increasing the fuel injection amount in accordance with the increase in the intake air amount is output without changing the target air-fuel ratio. This fuel injection amount is calculated by multiplying a relational expression of normal fuel injection by a correction coefficient for each cylinder. The correction coefficient is, for example, stored in advance in the ROM 62 in the ECU 60 for each cylinder by the rotational speed of the crankshaft 18 and the rotational speed of the cylinder. , A table value according to the opening of the electronically controlled throttle valve 40. FIG. 5 shows the tendency of the table and the table values. The table values are set so that the fuel injection amount is determined according to the opening of the electronically controlled throttle valve 40 without deteriorating the air-fuel ratio. Accordingly, the fuel injection amount is corrected from the injector 42 to the calculated fuel injection amount. With the increased intake air and the increased fuel injection, the air-fuel mixture maintaining the target air-fuel ratio is sent to the combustion chamber 6 and Is improved and stabilized. As a result, the fluctuation of the rotation speed of the crankshaft 18, that is, the rotation fluctuation converges,
Will be resolved. After the execution of S104 ends, the ECU 60
Exits this routine.

Next, in the second embodiment, after confirming the rotation of the engine and confirming the fluctuation amount of the rotation speed, the cylinder whose rotation speed is reduced most and the cylinder whose rotation speed is increased most are determined. In addition, the intake air amount and the fuel injection amount are adjusted. This is because, when the rotation fluctuation is not so large, when only the cylinder whose rotation speed is reduced most is driven to the open side, an unnecessary increase in the engine speed,
Conversely, vibration due to illegal rotation occurs, and to prevent this, the rotation of the crankshaft 18 can be stabilized by simultaneously driving the throttle opening of the cylinder whose rotation speed is being increased to the close side. It is. FIG. 6 shows a flowchart according to the second embodiment.

From S200 to S201, the above-described S1
Since it is the same as 00 to S101, detailed description is omitted.

In S202, which is executed subsequently, it is determined from the confirmed data of the fluctuation amount of the rotation speed which cylinder has generated the lowest rotation speed and which cylinder has generated the highest rotation speed. Next, the process proceeds to S203, where EC
U60 sets the throttle opening Δt to the electronically controlled throttle valve 40 of the cylinder generating the lowest rotational speed.
At the same time, a control signal is output to the electronically controlled throttle valve 40 of the cylinder that has generated the most increased rotational speed so as to drive the throttle opening to the closed side by Δth2. These Δth1 and Δth2 are
The opening degree of the electronically controlled throttle valve 40 corresponds to an increase in the intake air amount for performing stable combustion in consideration of the determined characteristics of each cylinder. This is, for example, the ECU 60
The relational expression between the rotational speed of the crankshaft 18 and the opening of the electronically controlled throttle valve 40 is obtained and given in advance in the ROM 62. When the electronically controlled throttle valve 40 is opened and closed by a predetermined amount by this signal output, the total intake air amount increases or decreases by that amount.

After adjusting the opening of the electronically controlled throttle valve 40,
In the next step, S204, the ECU 60 applies the above-described intake air to the injector 42 of each cylinder determined to have the lowest rotation speed or the highest rotation speed without changing the target air-fuel ratio. A signal for correction control for increasing or decreasing the fuel injection amount according to the increase or decrease in the amount is output.

This fuel injection amount is calculated by multiplying the relational expression for normal fuel injection by the correction coefficient for each cylinder, and the correction coefficient for each cylinder is set as a table value.
This is the same as the first embodiment. Accordingly, injection corrected to the calculated fuel injection amount is performed from the injector 42, and the air-fuel mixture maintaining the target air-fuel ratio is sent to the combustion chamber 6 by the above-mentioned increased / decreased intake air and the increased / decreased fuel injection, and each air-fuel mixture is sent to the combustion chamber 6. The combustion state of the cylinder changes. As a result, the rotation fluctuation of the crankshaft 18 converges and is eliminated. S20
After the execution of step 4, the ECU 60 exits this routine.

Further, in the third embodiment, the independent electronically controlled throttle valve 40 according to the first embodiment is applied to a multi-cylinder engine provided for each bank portion 36. That is, as shown as a conceptual diagram in FIG. 7, in the present example of the four-cylinder engine, a total of two electronically controlled throttle valves 40 are provided at one location in each bank.

The operation of the third embodiment will be described below with reference to the flowchart shown in FIG. ECU
60 starts this interrupt routine at predetermined time intervals, and S
Up to 300. S300 to S301 correspond to S10 described above.
Since it is the same as 0 to S101, detailed description is omitted. In S302 that is subsequently executed, the cylinder that has generated the lowest rotational speed is determined from the confirmed rotational speed variation data.

Here, in S303, the ECU 60
A control signal is output to the electronically controlled throttle valve 40 provided in the bank portion 36 having the cylinder whose rotational speed has been determined to have decreased the most so that the throttle opening is driven to the open side by Δth3. This Δth3 is an opening of the electronically controlled throttle valve 40 of the bank unit 36 corresponding to an increase in the amount of intake air for performing stable combustion in consideration of the characteristics of the determined cylinder. , ECU6
0 in the ROM 62 in the crankshaft 18 for each bank.
The relationship between the rotational speed of the motor and the opening of the electronically controlled throttle valve 40 is obtained in advance and given. When the electronically controlled throttle valve 40 is opened by a predetermined amount by this signal output, the total intake air amount increases by that amount.

After adjusting the opening of the electronically controlled throttle valve 40,
In the next step S304, the ECU 60 supplies the fuel injection amount corresponding to the increase of the intake air amount to the injector 42 of the cylinder determined to have the lowest rotational speed without changing the target air-fuel ratio. And outputs a signal of correction control for increasing the value. This fuel injection amount is calculated by multiplying a relational expression for normal fuel injection by a correction coefficient for each cylinder, and the correction coefficient for each cylinder is set as a table value in the same manner as in the first embodiment. is there. Therefore, the fuel injection amount is corrected from the injector 42 to the calculated fuel injection amount, the air-fuel mixture maintaining the target air-fuel ratio is sent to the combustion chamber 6, and the motion state of each cylinder is improved. As a result, the rotation fluctuation of the crankshaft 18 converges and is eliminated. Thereafter, the ECU 60 exits the routine.

Further, in the fourth embodiment, after confirming the rotation of the engine and confirming the amount of fluctuation of the rotation speed according to the third embodiment, the bank portion 36 having the cylinder whose rotation speed is reduced most is provided. And the bank portion 36 having the most increased cylinder is determined, and the intake air amount and the fuel injection amount are adjusted. This is for the same reason as in the second embodiment. FIG. 9 shows a flowchart according to the fourth embodiment.

From S400 to S401, the above-described S1
Since it is the same as 00 to S101, detailed description is omitted.

In S402, which is executed subsequently, it is determined on the basis of the confirmed data of the fluctuation amount of the rotation speed which cylinder has generated the lowest rotation speed and which cylinder has generated the highest rotation speed. . Next, proceed to S403,
The ECU 60 drives the electronically controlled throttle valve 40 of the bank portion 36 having the cylinder that has generated the lowest rotational speed by opening the throttle opening by Δth4 to the open side, and at the same time, generates the most increased rotational speed. A control signal is output to the electronically controlled throttle valve 40 of the bank section 36 having the closed cylinder so as to drive the throttle opening to the closing side by Δth5. Regarding Δth4 and Δth5,
This is the same as Δth1 and Δth2 according to the second embodiment. By this signal output, the electronically controlled throttle valve 40
Is opened and closed by a predetermined amount, and the total intake air amount increases and decreases by that amount.

After that, S404 is executed, and the ECU 60 sends a signal for correction control to each injector 42 of each bank 36 to increase or decrease the fuel injection amount according to the increase or decrease of the intake air amount without changing the target air-fuel ratio. Is output. This fuel injection amount is the same as in the second embodiment. Therefore, injection corrected to the calculated fuel injection amount is performed from the injector 42, and the air-fuel mixture maintaining the target air-fuel ratio is sent to the combustion chamber 6, and the motion state of each cylinder changes. As a result, the rotation fluctuation of the crankshaft 18 converges and is eliminated. After the execution of S404 ends, the ECU 60 exits this routine.

It should be noted that the present invention is not limited to the configuration of each of the above embodiments, and various modifications can be made within the scope of the invention. For example, each electronically controlled throttle valve 4
A pressure sensor (not shown) may be provided at a downstream position of 0, and the fuel may be injected from the injector 42 according to a negative pressure signal from the pressure sensor. In this case, since the actual intake pressure can be measured, it is possible to adjust the fuel injection amount to achieve the target air-fuel ratio more appropriately than by using a preset numerical value or a relational expression.

[0047]

As described above, according to the multi-cylinder engine according to the present invention, even if a rotation fluctuation occurs, the operation of each cylinder is stabilized by the improvement of the combustion state, so that the rotation fluctuation is eliminated. .

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an engine and a control system thereof according to an embodiment.

FIG. 2 is a time chart of the rotational speed of each cylinder according to the present embodiment.

FIG. 3 shows an ECU used in the embodiment of the present invention.
FIG.

FIG. 4 is a flowchart of a routine executed by an ECU in the embodiment of the present invention.

FIG. 5 is a table showing correction coefficient values based on a rotation speed of a crankshaft and an opening degree of an electronically controlled throttle valve, and a tendency thereof.

FIG. 6 is a flowchart of a routine executed by an ECU according to the second embodiment of the present invention.

FIG. 7 is a conceptual diagram showing an arrangement of an electronically controlled throttle valve provided for each bank unit.

FIG. 8 is a flowchart of a routine executed by an ECU according to the third embodiment of the present invention.

FIG. 9 is a flowchart of a routine executed by an ECU according to the fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine main body 6 Combustion chamber 18 Crankshaft 21 Crank angle sensor 22 Camshaft 24 Cam angle sensor 28 Air flow meter 32 Intake pipe 36 Bank part 40 Electric throttle valve 42 Injector 60 ECU

──────────────────────────────────────────────────の Continuation of front page (51) Int.Cl. ⁶ Identification code FI F02D 41/36 F02D 41/36 B 43/00 301 43/00 301H 301K 45/00 301 45/00 301C 362 362E F02M 69/00 F02M 69/00 320A

Claims (6)

[Claims] 1. An injector provided in an intake pipe for each cylinder to inject fuel toward a combustion chamber side of an engine, a crankshaft driven to rotate by power generated in each cylinder, and a rotation of the crankshaft. In a multi-cylinder engine having a crankshaft rotation speed detecting means for detecting a speed, a throttle valve provided in the intake pipe for each cylinder so as to be able to adjust an opening degree for adjusting an intake air amount to a combustion chamber of the engine, Cylinder discriminating means for discriminating from which cylinder the crankshaft rotational speed is due to power transmission; and based on a signal from the cylinder discriminating means and the crankshaft rotational speed detecting means, a difference in generated power for each cylinder. By controlling the opening degree of the throttle valve of each cylinder in accordance with the fluctuation amount of the rotation speed generated based on the A rotation speed control means for adjusting an intake air amount and adjusting a fuel injection amount of each cylinder by the injector in accordance with an adjustment amount of the intake air amount for each cylinder. engine. 2. The method according to claim 1, wherein the rotational speed control unit is configured to determine, based on signals from the cylinder discriminating unit and the crankshaft rotational speed detecting unit, a variation in the rotational speed caused by a difference in generated power for each cylinder. Operating the throttle valve of the cylinder whose rotation speed is reduced most in the opening direction to increase the intake air amount, and increasing the fuel injection amount of the cylinder by the injector according to the increase in the intake air amount. The multi-cylinder engine according to claim 1, wherein: 3. The rotation speed control means, in addition to increasing the intake air amount and the fuel injection amount of the cylinder whose rotation speed has been reduced most, further closes the throttle valve of the cylinder whose rotation speed has been increased most. 3. The multi-cylinder engine according to claim 2, wherein the amount of intake air is reduced by operating the fuel injection device, and the amount of fuel injected by the injector in the cylinder is reduced in accordance with the amount of decrease in the amount of intake air. 4. An injector provided in an intake pipe for each cylinder to inject fuel toward a combustion chamber side of an engine, a crankshaft driven to rotate by power generated in each cylinder, and rotation of the crankshaft. In a multi-cylinder engine having: a crankshaft rotation speed detecting means for detecting a speed; and a bank portion, which is an upstream branch portion branched for each cylinder in an intake pipe, adjusts an intake air amount to a combustion chamber of the engine. A throttle valve provided in the intake pipe so as to be adjustable in opening degree for each bank portion, a cylinder discriminating means for discriminating from which cylinder the power of the crankshaft rotational speed is transmitted, and a cylinder discriminating means and the crank. The fluctuation of the rotational speed caused by the difference in generated power for each cylinder based on a signal from the shaft rotational speed detecting means. The intake air amount is adjusted for each bank by controlling the opening of the throttle valve of each bank in accordance with the above, and the amount of fuel injected by the injector of each bank is adjusted to the amount of the intake air. A multi-cylinder engine comprising: a rotation speed control unit that adjusts the rotation speed for each bank unit in accordance with the rotation speed. 5. The rotation speed control unit, based on a signal from the cylinder discrimination unit and the crankshaft rotation speed detection unit, according to a fluctuation amount of the rotation speed caused by a difference in generated power for each cylinder, By operating the throttle valve of the bank having the cylinder with the lowest rotational speed in the opening direction to increase the amount of intake air, the amount of fuel injected by the injector of the bank is increased by the increment of the amount of intake air. The multi-cylinder engine according to claim 4, wherein the number is increased in response to the request. 6. The throttle speed of the bank portion having the cylinder whose rotational speed is increased in addition to the increase of the intake air amount and the fuel injection amount of the cylinder whose rotational speed is decreased most. 6. The valve according to claim 5, wherein the amount of intake air is reduced by operating a valve in a closing direction, and the amount of fuel injected by the injector in the bank portion is reduced in accordance with the amount of decrease in the amount of intake air. Cylinder engine.