JPH03134248A - Control method for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent an abnormal control, caused by misdetecting cylinder discrimination, and damage of an engine by providing constitution such that supply of fuel to each cylinder is stopped in the case of deciding a cylinder discrimination result not regular being based on a series pattern. CONSTITUTION:An arithmetic control part 12, first after finishing cylinder discrimination, referring to a series pattern in a register 11, decides whether a cylinder discrimination result is regular or not. That is, when a level of the second position signal L2 is stored in a riseup reference position B75 deg. of the first position signal L1, a regular series pattern is obtained, so that the result is decided regular, and a normal ignition control, based on the cylinder discrimination result, is performed. On the other hand, in the case of deciding the discrimination result not regular with the series pattern abnormal, an internal combustion engine is stopped by immediately stopping supply of fuel to all the cylinders. In this way, the engine can be prevented from being damaged without using the abnormal cylinder discrimination result due to misdetection for the ignition control.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an internal combustion engine control method that identifies the operating position of each cylinder from two systems of position signals and performs cylinder control based on the identification result and operating conditions. In particular, the present invention relates to an internal combustion engine control device that prevents engine damage due to erroneous cylinder detection.

[Prior Art] Conventionally, an internal combustion engine of an automobile or the like has been rotated by a plurality of cylinders (for example, four cylinders) at several tens of QrpmN and several 11,000 rpm. In the case of a four-cylinder engine, each cylinder is connected to the drive shaft (crankshaft) with a phase difference of 1/2 period, but for two revolutions of the crankshaft, intake, compression, explosion, and Since four exhaust cycles are performed, the operating position of the camshaft that controls the drive cycle of each cylinder is out of phase by 1/4 cycle.

In such internal combustion engines, position signals are generated for each cylinder in synchronization with the rotation of the internal combustion engine in order to electronically control the distribution of ignition signals to each cylinder, the determination of ignition timing, and the order of fuel injection by the injectors. However, it is necessary to identify the operating position of each cylinder based on this position signal.
Usually, a rotation signal generator that detects rotation of a camshaft or crankshaft of an internal combustion engine is used as a means for generating a position signal corresponding to a reference position of each cylinder.

FIG. 2 is a block diagram showing a general internal combustion engine control device. In the figure, (8) is a rotation signal generator that generates a position signal corresponding to each cylinder, (20) is a load (accelerator), Various sensors output operating condition signals representing speed, temperature, etc., and (9) is an interface circuit for taking in position signals and operating condition signals.

(10) is a microcomputer that performs fuel control and ignition control for each cylinder based on the position signal and operating condition signal inputted via the interface circuit (9), and the position signal for each reference position is serialized. The operating position of each cylinder is identified by referring to the register (11) stored as a pattern and the series pattern, and the fuel control unit (13), ignition control unit (14) and distribution are controlled based on the cylinder identification result and operating conditions. It also includes an arithmetic control section (12) that controls the control section (15).

FIG. 3 is a perspective view showing a general rotation signal generator (8) used in an internal combustion engine control device, and FIG. 4 is a circuit diagram showing a position signal generating section in the rotation signal generator (8). be.

In FIG. 3, (1) is a rotating shaft that rotates in synchronization with the crankshaft of an internal combustion engine.
The cylinder is connected to a camshaft that rotates once in synchronization with one cycle of four-cycle operation of one cylinder.

(2) is a rotating disk attached to the rotating shaft (1), and there are a plurality of rotating discs at positions corresponding to the reference position (predetermined rotation angle) for each cylinder and at positions corresponding to the reference position of a specific cylinder. Slit-shaped windows (3a) and (3b) are provided. Here, the case where the internal combustion engine is a four-cylinder engine is shown, and regarding the windows (3a) provided at four locations along the outer periphery, one end on the front side with respect to the rotation direction (arrow) is the first end of each cylinder.
corresponds to the reference position, and one end on the rear side corresponds to the second reference position.

Further, the window (3b) provided at one location on the inner circumference is arranged to correspond to the window (3a) of only one specific cylinder (first cylinder), and has a phase difference with respect to the window (3a). have.

(4a) and (4b) are a pair of light emitting diodes arranged to face each other, respectively. A pair of photodiodes arranged to receive output light through windows (3a) and (3b).

These light emitting diodes (4a) and (4b) and photodiodes (5a) and (5b) constitute two sets of photocouplers.

In FIG. 4, light emitting diodes (4a) and (4b)
The photodiodes (5a) and (5b) are typically shown as (4) and (5), and only one photocoupler having the same configuration is shown.

(6) is an amplifier circuit that amplifies the output signal from the photodiode (5), and (7) is an open collector (grounded emitter) output transistor whose base is connected to the output terminal of the amplifier circuit (6). The collector terminal of the output transistor (7) is connected to an interface circuit (9) (see FIG. 2).

Next, the operation of the conventional internal combustion engine control device shown in FIGS. 2 to 4 will be described with reference to the waveform diagram in FIG. 5.

The rotating shaft (1) rotates together with the internal combustion engine to form a rotating disk (2).
When the rotation signal generator (8) rotates, the window (3a
) and (3b), each of the photodiodes (5a) and (5b) of two sets of photocouplers placed opposite each other, rises at the front end and rear end of the slit forming the windows (3a) and (3b). Two types of position signals L1 and L2 (see FIG. 5) are output.

In FIG. 5, the first position signal obtained based on the window (3a) is a crank angle reference signal called SGT, which is inverted at a predetermined crank angle for each cylinder #1 to #4. Here, the rise (B75°) of each crank angle reference signal is the first reference position 75° before the crank angle 0° position (TDC - upper dead center) for each cylinder, and the control reference and corresponds to the initial energization angle. Also, the falling edge (B5°) is the TD of each cylinder.
This is the second reference position 5″ before C and corresponds to the initial ignition angle.

The second position signal L2 obtained based on the window (3b) is
This is a cylinder identification signal called SGC, and it is a cylinder identification signal called SGC.
It is output when a position signal is generated for the cylinder (cylinder) and is used to identify the #1 cylinder.

The operating position of each cylinder is shifted by 1/4 period with respect to one period of the camshaft (corresponding to two periods of the crankshaft, or 720 degrees), and is deviated by 1/2 period with respect to one period of the crankshaft. In the case of four cylinders, the cylinders are shifted by a cycle (180°), and as is well known, each cylinder is drive-controlled in the order of #1 cylinder, #3 cylinder, #4 cylinder, and #2 cylinder.

On the other hand, the cylinder identification signal L2 is set to rise before the rise of the crank angle reference signal L1 corresponding to the specific #1 cylinder and fall after the fall of the position signal L1.

The two types of position signals L2 and L2 thus obtained are input to the microcomputer (1o) via the interface circuit (9), along with the operating condition signal.

The microcomputer (10) controls the second
The level of the position signal L2 is stored in the register (11) as a series pattern, and the series pattern is referred to via the arithmetic control section (12) to identify the operating position of each cylinder including the specific cylinder. Further, the arithmetic control section (12) in the microcomputer (10) performs control calculations such as ignition timing based on the operating condition signal, and determines the optimum target ignition position and fuel for each cylinder according to the operating condition. Calculate the injection position (including order, group injection, etc.). Based on the calculation results, the fuel control section (13), ignition control section (14), and distribution control section (15) are controlled. As a result, the optimum control signal is distributed to each cylinder.

However, if the position signal becomes abnormal due to a photocoupler failure in the rotation signal generator (8), ignition distribution control for normal cylinders cannot be performed, and abnormal cylinder identification results due to erroneous detection may occur. This will be reflected in the ignition control.
For example, if a cylinder is accidentally ignited during air-fuel mixture intake, there is a risk of igniting the fuel supply system and causing damage to the internal combustion engine.

[Problems to be Solved by the Invention] As described above, the conventional internal combustion engine control method does not have a function to determine abnormalities in the position signal, so cylinder errors may occur due to failure of the rotation signal generator (8), etc. When detection occurs, the abnormal cylinder identification result is reflected in ignition control, causing engine damage.

This invention was made to solve the above-mentioned problems, and provides internal combustion engine control that prevents abnormal control due to erroneous detection of cylinder identification and prevents engine damage even when the position signal becomes invalid. The purpose is to obtain a method.

[Means for Solving the Problems] In the internal combustion engine control method according to the present invention, when it is determined that the cylinder identification result is not normal based on the series pattern,
The fuel supply to each cylinder is stopped.

[Operation] In the present invention, when an abnormality in the system pattern is determined from the contents of the register, fuel supply to all cylinders is immediately stopped to stop the internal combustion engine.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a flow chart diagram showing one embodiment of the present invention. Note that the apparatus to which this invention is applied is as shown in FIGS. 2 to 4, and it is only necessary that a part of the program of the arithmetic control unit (12) in the microcomputer (10) is changed. Further, the pulse waveform of the position signal used for cylinder identification is the same as that shown in FIG.

First, after the cylinder identification step St (not explained here) similar to the above is completed, the arithmetic control unit (12) refers to the system pattern in the register (11) and determines whether the cylinder identification result is normal or not. Determination is made (step s6).

That is, the rising reference position (B7) of the first position signal L1
5°), the normal system pattern is rlooo, so if the system pattern is rlooo, it is determined to be normal, and the normal system pattern based on the cylinder identification result is determined to be normal. Perform ignition control (step S
3).

On the other hand, if it is determined in step S2 that the system pattern is abnormal and the identification result is not normal, fuel supply to all cylinders is immediately stopped and the internal combustion engine is stopped (step S4).

As a result, abnormal cylinder identification results due to erroneous detection are not used for ignition control, and engine damage can be prevented.

[Effects of the Invention] As described above, according to the present invention, when it is determined that the cylinder identification result is not normal based on the series pattern, fuel supply to each cylinder is stopped and the position signal is abnormal due to some kind of failure. Even if this happens, the internal combustion engine is stopped immediately, so there is an effect of providing an internal combustion engine amount control method that can prevent engine damage.

[Brief explanation of the drawing]

FIG. 1 is a flow chart diagram showing an embodiment of the present invention;
FIG. 2 is a block diagram showing a general internal combustion engine control device.
3 is a perspective view showing a general rotational signal generator used in the internal combustion engine control device shown in FIG. 2; FIG. 4 is a circuit diagram showing a position signal generating section in the rotational signal generator shown in FIG. 3; FIG. 5 is a waveform diagram showing a position signal generated by the rotation signal generator of FIGS. 3 and 4. FIG. (8... Rotation signal generator (10... Microcomputer (11... Register (12)... Arithmetic control section (13... Fuel control section (14)... Ignition control section (15 ...Distribution control unit (20)...Various sensors B75@, B5''...Reference position,...First position signal B2...Second position signal D...Operating condition signal S2... Step S3 to determine the cylinder identification result...
The step of stopping the fuel supply. In the diagram, the same reference numerals are the same.
or a corresponding portion.

Claims (1)

[Claims] The first line indicates the reference position of each cylinder in synchronization with the rotation of the internal combustion engine.
a rotation signal generator that outputs a position signal and a second position signal indicating a specific cylinder; various sensors that output operating condition signals; and a level of the second position signal at the reference position that is stored as a series pattern. and a microcomputer that identifies the operating position of each cylinder based on the series pattern and performs fuel control and ignition control of each cylinder based on the cylinder identification result and the operating condition signal. An internal combustion engine control method, characterized in that, in the engine control method, when it is determined that the cylinder identification result is not normal based on the series pattern, fuel supply to each of the cylinders is stopped.