JPH0921342A - Cylinder judging device for multi-cylinder internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance accuracy in cylinder judgement, and surely prevent the erroneous discrimination of each cylinder. SOLUTION: The device is provided with a position signal generating device 5 generating a position signal every unit rotation angle, and with a reference signal generating device 8 generating a reference signal corresponding to the specified position of a piston for each cylinder. Respective three reference signals are generated for each cylinder, and the generating space of each signal generated is made different by each cylinder. In a control unit 10, it is judged whether or not the number of the position signals generated within a space between generations of reference signals is roughly identical while being continuous two times, if the answer is YES, it is judged that the detection of noise as a reference signal is possibly low, and the cylinder is thereby discriminated, and no cylinder is discriminated at all in case other than the aforesaid case. Therefore, the cylinder can thereby be discriminated with high accuracy, and the erroneous discrimination of the cylinder can thereby be prevented to the utmost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for discriminating cylinders of a multi-cylinder internal combustion engine.

[0002]

2. Description of the Related Art Accurate cylinder discrimination is required to appropriately perform fuel supply control and ignition control in a multi-cylinder internal combustion engine. Conventionally, as an apparatus for performing such cylinder discrimination, for example, There are the following.
That is, by providing slits or protrusions for each unit rotation angle of the crankshaft on the circumference of a rotating disk fixed to the crankshaft or camshaft of the internal combustion engine, and detecting this with an electromagnetic pickup sensor, etc. The unit rotation angle signal (hereinafter, also referred to as a position signal) is generated.

On the other hand, slits or protrusions are provided on the circumference of a rotating disk fixed to the crankshaft or camshaft of an internal combustion engine at a position corresponding to a predetermined reference position of the piston of each cylinder.
By detecting this with an electromagnetic pickup type sensor or the like, a reference position signal of the piston of each cylinder (hereinafter, also referred to as a reference signal) is generated. For example, a similar signal is generated at a predetermined interval from the reference signal. It is generated (another reference signal is generated at a piston position different from the predetermined reference position), and the generation interval is made different for each cylinder.

Some cylinders are capable of discriminating a specific cylinder by counting the number of position signals generated within a reference signal generation interval which is different for each cylinder.

[0005]

However, the conventional cylinder discriminating apparatus as described above has the following problems. That is, as shown in FIG. 5, when noise or the like is mixed between the reference signals, the noise is recognized as a reference signal that is normally generated, and the number of position signals counted between the reference signal and the noise is counted. However, if the value is equivalent to the specific cylinder, the cylinder discrimination is erroneously performed.

Such erroneous cylinder discrimination has an adverse effect on fuel supply control and ignition control, and there is a possibility that engine operation cannot be performed normally. For example, at the time of starting, etc., until the cylinders are discriminated, simultaneous injection or simultaneous ignition is performed for all cylinders or a specific cylinder group to improve startability, while normal fuel supply is performed after the cylinders are discriminated. In the case where the control or ignition control is performed, even if the cylinder is erroneously discriminated, it will be judged that the cylinder discrimination is completed at that time. Normal fuel supply control and ignition control will be started, which may cause unstable combustion of the engine.

The present invention has been made in view of the above conventional circumstances, and an object of the present invention is to provide a cylinder discriminating apparatus for a multi-cylinder internal combustion engine capable of reliably preventing erroneous discrimination of cylinder discrimination.

[0008]

Therefore, a cylinder discriminating apparatus for a multi-cylinder internal combustion engine according to a first aspect of the present invention, as shown in FIG. 1, has a position for each predetermined rotation angle of the crankshaft of the internal combustion engine. Position signal generating means for generating a signal and at least three reference position signals corresponding to a predetermined position of the reciprocating piston are generated for each cylinder at substantially the same intervals, and the generation intervals are made different for each cylinder. The reference signal generating means, the generated position signal number detecting means for detecting the number of position signals generated within the reference signal generating interval, and the number of position signals detected by the generating position signal number detecting means are at least 2 At least 2 by the position signal number judging means for judging whether or not they are substantially equal to each other consecutively, and the position signal number judging means. When it is determined that substantially equal in succession, and configured to include a cylinder discrimination means for discriminating a specific cylinder based on the number of detected position signal by the generating position signal number detecting means.

In the cylinder discriminating apparatus for a multi-cylinder internal combustion engine according to the present invention having such a configuration, at least three reference signals are provided to each cylinder at substantially the same intervals, and the reference signals of the reference signals are set at the same intervals. A reference signal is generated by making the generation interval different for each cylinder, and it is determined whether or not the number of position signals generated within the reference signal generation interval is substantially the same at least twice. If the noises are substantially the same in succession, it is extremely unlikely that noise was detected as a reference signal, and it is highly probable that the three detected reference signals are three reference signals corresponding to the same cylinder. Only in such a case, the cylinder discrimination is performed based on the detected position signal number. As a result, highly accurate cylinder discrimination can be performed, and erroneous cylinder discrimination can be prevented as much as possible.

According to the second aspect of the invention, after the cylinder discriminating means discriminates the specific cylinder, the ignition control is performed based on the discriminated cylinder, and the cylinder discrimination is normally performed based on the engine rotation speed thereafter. It is configured to include a cylinder discrimination normality determination means for determining whether or not it has been performed. In the invention according to claim 2, after the cylinder discriminating means discriminates the specific cylinder, the ignition control is performed based on the discriminated cylinder, and the cylinder discrimination is normally performed based on the engine rotation speed thereafter. It is determined whether or not it has been performed. As a result, the cylinder discrimination accuracy can be further improved.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. A cylinder discriminating apparatus for a multi-cylinder internal combustion engine (here, a four-cylinder internal combustion engine will be described as an example) will be described with reference to FIG. As shown in FIG. 2, the internal combustion engine 1 according to the present embodiment includes a position signal rotor 3 that rotates in conjunction with a crankshaft 2 (or a camshaft), and a predetermined crankshaft 2 for the position signal rotor 3. (Unit) An electromagnetic pickup sensor 4 arranged facing a slit or protrusion 3A provided for each rotation angle, and a signal is generated for each predetermined crank rotation angle (unit rotation angle). A position signal generator 5 for transmitting the signal to the control unit 10 is provided. The position signal generating device 5 corresponds to the position signal generating means according to the present invention.

Further, a reference signal rotor 6 which rotates in conjunction with the crankshaft 2 (or a camshaft) and a slit or a slit provided at a position corresponding to a predetermined position of the piston of each cylinder of the reference signal rotor 6 An electromagnetic pickup type sensor 7 arranged facing the protrusion 6A is included, and a reference signal generator 8 that generates a reference signal at a predetermined piston position of each cylinder and sends the reference signal to the control unit 10. It is provided.

In the reference signal generator 8 according to the present embodiment, as shown in FIG. 3, three reference signals are generated for each cylinder, and the generated reference signal intervals are set for each cylinder. It's different. Such reference signal generator 8
Corresponds to the reference signal generating means of the present invention. By the way, as the control unit 10, a control unit used for engine control can be used.
It is configured by including an OM, a RAM, an A / D converter, an input / output I / F, and the like. The control unit 10 is
The software has the functions of the generated position signal number detection means, the position signal number determination means, the cylinder determination means, and the cylinder determination normality determination means according to the present invention.

Now, the cylinder discrimination control performed by the control unit 10 in this embodiment will be described with reference to the flowchart of FIG. In step (denoted by S in the figure, the same applies hereinafter) 1, it is determined whether or not the start of the engine is started. If YES, then proceed to step 2, N
If it is O, this flow ends. The determination can be made by, for example, whether or not a key switch (not shown) has been moved to the start position, or whether power supply to a starter motor (not shown) has been started, or the like. A start-up detection method can be used.

In step 2, when a reference signal is detected (for example, REF _{x- 2 in} FIG. 3 corresponds), counting of the position signal POS is started. Step 3
Then, when the next reference signal is input (for example,
REF _{x-1 in} FIG. 3 corresponds to the position signal generated between the previous reference signal (REF _{x-2 in} FIG. 3) input and the current reference signal (REF _{x-1 in} FIG. 3) input. After storing the count number as NP ₁ , the count number is reset again to start counting the number of position signals.

In step 4, when the next reference signal is input (for example, REF _x in FIG. 3),
After storing the count number of the position signal generated between the input of the previous reference signal (REF _{x-1 in} FIG. 3) and the input of this reference signal (REF _{x in} FIG. 3) as NP ₂ , the count number is again set. Reset and start counting the number of position signals.

At step 5, NP ₁ and NP ₂ are compared with each other to determine whether NP ₁ = NP ₂ ± 1-2. If YES, the possibility of noise generation is low (noise is extremely unlikely to be detected as a reference signal), and the three detected reference signals may be the three reference signals generated in the same cylinder. If it is determined to be high, and the cylinder can be determined, the process proceeds to step 6.

If NO, noise is generated (whether or not noise is erroneously detected as a reference signal), or the three detected reference signals include reference signals generated in other cylinders. If it is determined that the cylinders cannot be identified, the process proceeds to step 11. In step 6, NP ₁ (or NP
₂ ) is N ± 1-2 stored in advance for each cylinder,
It is determined whether any of the values corresponds.

If YES, there is a corresponding value, so
It is determined that the cylinder can be discriminated, and the process proceeds to step 7 to discriminate the cylinder based on the value. On the other hand, if NO,
Since there is no corresponding value, it is determined that there is a high possibility that noise is occurring in the reference signal or the position signal, and the process proceeds to step 11.

In step 8, since the cylinder can be discriminated, the ignition control is started based on the corresponding cylinder. In step 9, the engine speed Ne is a predetermined value N _O (e.g., the rotational speed when the complete explosion is obtained) determines whether a higher. If YES, go to step 10,
If NO, go to step 11.

In step 11, after setting the current NP ₂ to NP ₁ , the process returns to step 4, and the above steps are repeated until YES is determined in steps 5, 6, and 11. ing. In step 10, the engine speed normally increases, the ignition control started in step 8 is correct, that is, it is determined that the cylinder discrimination can be normally performed, and the fuel supply control and the ignition control are shifted to the normal control. This flow ends.

As described above, according to this embodiment, three reference signals are generated at the same intervals for each cylinder, and the intervals at which the reference signals are generated are different for each cylinder. , When the number of position signals generated within the reference signal generation interval is substantially the same twice in succession, it is extremely unlikely that noise was detected as a reference signal, and the three detected reference signals are the same cylinder. It is judged that there is a high possibility that there are three reference signals corresponding to, and the cylinder discrimination is performed only in such a case, and the cylinder discrimination is not performed in other cases. Therefore, highly accurate cylinder discrimination should be performed. Therefore, it is possible to prevent erroneous cylinder discrimination as much as possible.

Therefore, it is possible to prevent the normal fuel supply control and the ignition control from being started for the erroneously specified cylinder and to adversely affect the engine operation. Further, in the present embodiment, in step 6, the NP
₁ or NP ₂ is stored in advance for each cylinder N ± 1
It is determined whether or not any of the two values corresponds to the engine rotation speed Ne.
Since it is determined whether or not is equal to or greater than the predetermined value N _O , the cylinder discrimination accuracy can be further improved.

By the way, in the present embodiment, since the position signal generator 5 and the reference signal generator 8 which are normally provided for engine control can be utilized to perform cylinder determination with high accuracy, for example, in the conventional case, In order to obtain the same degree of cylinder discrimination accuracy as in the case of the embodiment, a cylinder discriminating device is exclusively used for discriminating cylinders as compared with the case where a dedicated device for generating a cylinder discriminating signal is provided separately from these normally equipped devices. Since it is not necessary to additionally install the rotor, the electromagnetic pickup type sensor, etc., the simplification of the configuration can be promoted.

In this embodiment, the position signal and the reference signal are generated by using the electromagnetic pickup type sensor, but the present invention is not limited to this.
Of course, the present invention can be applied to the case where a position signal or a reference signal is generated by using an optical or Hall element type sensor. Further, in the present embodiment, three reference signals are generated for one cylinder at the same interval, and the intervals are varied for each cylinder to determine the cylinder. However, for one cylinder, It is also possible to generate three or more reference signals at the same intervals and to perform cylinder discrimination based on these.

[0026]

As described above, according to the cylinder discriminating apparatus for a multi-cylinder internal combustion engine according to the first aspect, the cylinder discrimination can be performed with high accuracy without complicating the structure as compared with the conventional apparatus. be able to. According to the second aspect of the invention, the cylinder discrimination accuracy can be further improved.

[Brief description of drawings]

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

FIG. 2 is an overall configuration diagram of an embodiment of the present invention.

FIG. 3 is a time chart for explaining a generation state of a REF signal and a POS signal in the same embodiment.

FIG. 4 is a flowchart illustrating cylinder discrimination control according to the above embodiment.

FIG. 5 is a diagram illustrating a problem in a conventional example.

[Explanation of symbols]

 1 Internal Combustion Engine 2 Crankshaft 3 Position Signal Rotor 3A Position Signal Protrusion 4 Position Signal Electromagnetic Pickup 5 Position Signal Generator 6 Reference Signal Rotor 6A Reference Signal Protrusion 7 Reference Signal Electromagnetic Pickup 8 Reference Signal Generator 10 control unit

Claims (2)

[Claims] 1. A position signal generating means for generating a position signal for each predetermined rotation angle of a crankshaft of an internal combustion engine, and a reference position signal corresponding to a predetermined position of a reciprocating piston at substantially the same intervals for each cylinder. Generate at least three,
Further, reference signal generating means for varying the generation interval for each cylinder, generated position signal number detection means for detecting the number of position signals generated within the reference signal generation interval, and the generated position signal number detection means. When the number of position signals detected by the position signal number determination means determines whether or not the position signal number is substantially equal at least twice in succession, and when the position signal number determination means determines that the number of position signals is substantially equal at least twice in succession. And a cylinder discriminating means for discriminating a specific cylinder based on the number of position signals detected by the generated position signal number detecting means, and a cylinder discriminating apparatus for a multi-cylinder internal combustion engine. 2. After the cylinder discriminating means discriminates a specific cylinder, ignition control is performed based on the discriminated cylinder, and it is determined whether or not the cylinder discrimination is normally performed based on the engine rotation speed thereafter. 2. The cylinder discriminating apparatus for a multi-cylinder internal combustion engine according to claim 1, wherein the cylinder discriminating device is configured to include a cylinder discriminating normality determining unit.