JPH0733806B2 - Multi-cylinder engine controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a roughness control device that controls a multi-cylinder engine so as to eliminate variations in the combustion state among the cylinders, so-called roughness.

(Prior Art) Conventionally, in a multi-cylinder engine, for example, as a roughness control for eliminating the variation in the combustion state between the cylinders that causes the vibration of the engine, for example, Japanese Patent Publication No.
As shown in Japanese Patent Laid-Open No. 56-33569, the combustion state of each cylinder is detected by the rotational angular velocity and combustion pressure of the engine, and the air-fuel ratio and the like for each of the cylinders are uniformly controlled based on the detected combustion state. It is known to eliminate the variation (roughness) in the combustion state of.

(Problems to be Solved by the Invention) However, in the above-described conventional roughness control device, when the roughness occurs due to the detection of the combustion state of each cylinder, the air-fuel ratios of all the cylinders are uniformly adjusted to occur between the cylinders. Since it controls the roughness, there is no problem when aligning another cylinder with a cylinder in good combustion condition, but when aligning another cylinder with a cylinder in poor combustion condition, it runs well until then. The cylinders that were already in operation will be aligned with the cylinders in a poor combustion state, which may rather deteriorate the combustion state in that cylinder.

On the other hand, Japanese Examined Patent Publication No. 56-50114 and Japanese Unexamined Patent Publication No. 57-129260 disclose a knocking level for each cylinder,
It has been proposed to optimally control the ignition timing for each cylinder. However, in this case, although it is effective in suppressing knocking of each cylinder individually, the combustion state of each cylinder is not uniformly arranged, which may rather cause roughness.

The present invention has been made in view of the above points, and an object thereof is to detect the rotational angular velocity of each cylinder in a multi-cylinder engine and to determine the maximum angular velocity of each cylinder in each cylinder. By controlling each cylinder so that it becomes an optimum value determined by the intake negative pressure, variation in the combustion state that occurs between the cylinders is eliminated, and roughness is eliminated, and the combustion state of each cylinder is optimized. And efficient roughness control.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention is
As shown in the figure, the angular velocity detecting means for detecting the rotational angular velocity of each cylinder, various control means for controlling the combustion state of each cylinder, and the output of the angular velocity detecting means, and the maximum angular velocity of each cylinder at that time Combustion adjusting means is provided for adjusting the various control means so as to match the optimum reference maximum angular velocity value determined by the engine speed and the intake negative pressure for each cylinder.

(Operation) As a result, the maximum angular velocity of each cylinder is compared with the reference maximum angular velocity value indicating the optimum combustion state for each cylinder, and the fuel injection amount from the combustion injector is adjusted so as to match the reference maximum angular velocity value. Various factors that govern the combustion state, such as ignition timing and ignition timing, are adjusted.

(Effects of the Invention) Therefore, according to the control device for a multi-cylinder engine according to the present invention, the reference maximum speed values indicating the optimum combustion state of each cylinder are detected by detecting the rotation angular speed of each cylinder. Since various elements that govern the combustion state are adjusted so that the combustion state of all cylinders is adjusted, efficient roughness control can be performed while maintaining good combustion states of all cylinders.

(Example) Hereinafter, the Example of this invention is described in detail based on drawing.

FIG. 2 shows an overall schematic configuration according to an embodiment of the present invention. In the figure, 1 is a four-cylinder engine having first to fourth cylinders 1a to 1d, and 2 is an intake passage for supplying intake air to the engine 1. The downstream side of the intake passage 2 is the first
~ It branches into the 4th branch passages 2a-2d, and is open for free passage to the corresponding cylinders 1a-1d, respectively. Each of the branch passages 2a to 2d
Fuel injection valves 3a to 3d as control means for controlling the combustion state of the cylinders 1a to 1d are arranged in the respective cylinders. Further, the intake passage 2 upstream of the collecting portion of the first to fourth branch passages 2a to 2d.
Is provided with a throttle valve 4 for controlling the intake air amount, and an air flow meter 5 for detecting the intake air amount is provided in the intake passage 2 upstream of the throttle valve 4. An igniter 6 controls the operation of spark plugs (not shown) of the cylinders 1a to 1d.

Further, a disc 8 for detecting a crank angle is integrally attached to the shaft end of the crank shaft 7 of the engine 1.
A crank angle sensor 9 for detecting the crank angle, the engine rotation speed and the rotation angular velocity thereof by the rotation angle of the disc 8 is provided opposite to. The crank angle sensor 9 constitutes an angular velocity detecting means for detecting the rotational angular velocity of each cylinder 1a to 1d. The output signal of the crank angle sensor 9 detects the ignition pulse signal to the ignition plug of the igniter 6, the output signal of the water temperature sensor 10 that detects the cooling water temperature of the engine, and the intake negative pressure downstream of the throttle valve 4 in the intake passage 2. Along with the output signal of the negative pressure sensor 11, it is input to a control circuit 12 composed of a microcomputer.
The fuel injection valves 3a to 3d are controlled by 12 so as to adjust the fuel injection amount.

Next, the operation of the control circuit 12 will be described with reference to FIGS. 3 to 5. FIG. 3 shows a main routine for controlling the roughness, and FIGS. 4 and 5 show one of the main routines. The subroutine as a part is shown. In the main routine of FIG. 3, after starting, first, in a first step S ₁ , an ignition pulse signal at a certain crank angle is input, and in a second step S ₂ , the ignition pulse signal timing is obtained in advance for each cylinder. Cylinder discrimination is performed by collating with the reference pulse generation timing corresponding to. Thereby, the third step S ₃ in the engine rotational speed for the first cylinder 1a for example the above determination, inputs the respective signals of the intake negative pressure and the cooling water temperature, corresponding to the first cylinder 1a in the fourth step S ₄ The ignition pulse signal is inputted as a rotation pulse signal by a trigger action through the trigger circuit, and further the fifth step S ₅
Then, the angular velocity corresponding to the cylinder is calculated from the input rotation pulse signal corresponding to the first cylinder 1a, and the value ω of the maximum angular velocity is obtained.

Next, in a sixth step S ₆ , it is determined whether or not the maximum angular velocity ω obtained as described above is larger than the optimum reference maximum angular velocity ω ₀ which is experimentally obtained in advance by the engine speed and the intake negative pressure. To do. When the maximum angular velocity ω is smaller than the reference maximum angular velocity ω ₀ , that is, the maximum angular velocity ω of the first cylinder 1a
If the slow NO, the process proceeds to a seventh step S _7, that the first sub-routine, or the air-fuel ratio to rich by increasing the fuel injection amount of the fuel injection valve 3a as shown in FIG. 4, or advances the ignition timing Or, secondarily, reduce the EGR amount,
By enhancing the swirl, the output is promoted so that the maximum angular velocity of the first cylinder 1a matches the reference maximum angular velocity ω ₀ . On the other hand, when the maximum angular velocity ω is larger than the reference maximum angular velocity ω ₀ , that is, the first cylinder 1a
If the maximum angular velocity ω of is YES, the eighth step S ₈
That is, the routine proceeds to the second subroutine, and as shown in FIG. 5, the fuel injection amount of the fuel injection valve 3a is reduced to make the air-fuel ratio lean, or the ignition timing is delayed, and secondarily,
By increasing the EGR amount and weakening the swirl, the output improvement is suppressed and the maximum angular velocity ω of the first cylinder 1a is made to match the reference maximum angular velocity ω ₀ .

Then, in the ninth step S _9, this time the engine speed for the third cylinder 1c, enter the respective signals of the intake negative pressure and the cooling water temperature, via the trigger circuit of the ignition pulse signal in the tenth step S ₁₀ triggers By inputting as a rotation pulse signal by the action, in the 11th step as in the case of the first cylinder 1a.
The rotation angular velocity of the third cylinder 1c corresponding to the ignition pulse signal calculated in S ₁₁ and determines the value of the maximum angular velocity omega. Thereafter, 12th step and the reference maximum angular velocity omega ₀ determined by the maximum angular velocity omega and the engine speed and the intake negative pressure compared to determine at S _12, the maximum angular velocity omega is smaller than the reference maximum angular velocity omega ₀ NO In the case of, the process proceeds to the 13th step S _13, that is, the first subroutine, and in the case of YES where the maximum angular velocity ω is larger than the reference maximum angular velocity ω ₀ , the 14th step S ₁₄
In other words, the procedure proceeds to the second subroutine to adjust various control means such as the fuel injection valve 3c that respectively governs the combustion state,
The maximum angular velocity ω of the cylinder 1c is made to match the reference maximum angular velocity ω ₀ .

Thereafter, in the same manner as above, the fourth cylinder 1d,
The second cylinder 1b, was treated in the same manner as the third step S ₃ through the eighth step S _8, and thereafter, a series of roughness control returns to the third step. Therefore, by such control, the maximum angular velocity ω of each cylinder 1a to 1d is changed to each cylinder 1a to 1d.
Of the fuel injection valve to match the optimum reference maximum angular velocity ω ₀ determined by the engine speed and the intake negative pressure.
Combustion adjusting means is arranged to adjust various control means such as 3a to 3d.

Therefore, according to the above-described embodiment, the maximum angular velocity ω of each cylinder 1a to 1d becomes the value of the optimum reference maximum angular velocity ω ₀ experimentally determined by the engine speed and the intake negative pressure for each cylinder 1a to 1d. Fuel injection valve 3a for each cylinder 1a-1d
Since it adjusts various control means such as 3d, it does not deteriorate the operating condition of the cylinder which was good until then as in the case of uniformly controlling all the conventional cylinders. It is possible to perform efficient roughness control while ensuring a good combustion state of 1d.

Of course, the present invention can be applied not only to the four-cylinder engine as in the above-described embodiment but also to many multi-cylinder engines.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. 2nd
FIG. 5 shows an embodiment of the present invention, FIG. 2 is an overall schematic configuration diagram, FIG. 3 is a flow chart diagram showing a main routine of a control circuit, and FIGS. 4 and 5 are respectively first control circuit. It is a flowchart figure which shows and a 2nd subroutine. 1 ... Engine, 1a-1d ... 1st-4th cylinder, 3a-3d ...
... Fuel injection valve, 6 ... Igniter, 9 ... Crank angle sensor, 10 ... Water temperature sensor, 11 ... Negative pressure sensor, 12 ... Control circuit.

Claims (1)

[Claims] 1. An angular velocity detecting means for detecting a rotational angular velocity of each cylinder, and various control means for controlling a combustion state of each cylinder,
Receiving the output of the angular velocity detection means, the various control means are adjusted so that the maximum angular velocity of each cylinder matches the optimum reference maximum angular velocity value determined by the engine speed and the intake negative pressure for each cylinder at that time. A control device for a multi-cylinder engine, comprising: a combustion adjusting means.