JPH0684739B2 - Cylinder identification device for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cylinder identification device for an internal combustion engine that identifies a cylinder from a signal of one system of a rotation signal generator.

[Prior Art] A signal synchronized with the rotation of the engine is used to control the ignition timing, fuel injection, and the like of the internal combustion engine. This signal generator usually detects the rotation of the camshaft or crankshaft of the engine. An example of such a rotation signal generator is shown in FIGS. 3 and 4. In the figure, (1) is a rotating shaft that rotates in synchronization with an engine (not shown), (2) is a rotating disk attached to the rotating shaft (1), and a window is provided at a location corresponding to a desired detection angle. (3) is provided. (4) is a light emitting diode, (5) is a photodiode for receiving the output light from the light emitting diode (4), (6) is connected to the photodiode (4), and amplifies the output signal of the photodiode (4) The amplifier circuit (7) is connected to the amplifier circuit (6) and is an open-collector output transistor. The window (3 ') for identifying a specific cylinder is asymmetrical to the window (3) for identifying another cylinder, and the rotating plate (2)
It is provided in.

Therefore, the rotation signal generator outputs a signal as shown in FIG. This signal is for a specific cylinder (# 1 cylinder)
Of the other cylinders (# 2 cylinder, # 3 cylinder, # 4 cylinder) is delayed by 10 ° (ATDC5 °) (top dead center at 5 °) from the other cylinders. Same (BTDC75 °).

Next, the specific cylinder identifying operation will be described with reference to FIGS. 6 and 7. The output signal of the rotation signal generator (8) shown in FIG. 5 is input to the microcomputer (10) via the interface circuit (9). In the microcomputer (10), cylinder identification is performed according to the flowchart shown in FIG. First, in step S1, the "high" level output period (t) and its rising section period (T) of the signal waveform of FIG. 5 are calculated. Then go to step S2,
Calculate the ratio (t / T). Then, in step S3, t ₁ / T>
An average threshold value α _n that satisfies α> t ₀ / T is set, and α _n is calculated using the following arithmetic expression.

α _n = (1-k) α _n-1 + k (t / T) _n where k = constant.

The α _n calculated in step S3 is compared with the ratio t / T (step S4), and if t / T-α _n > 0, it is identified as a specific cylinder and an identification flag is set (step S5). Also, step S4
If t / T-α _n <0, it is distinguished from other cylinders.

[Problems to be Solved by the Invention] In the conventional cylinder identification device for an internal combustion engine as described above, the duty of the signal with respect to the output signal cycle corresponding to the cylinder obtained from the rotation signal generator is abnormal due to engine rotation fluctuation or the like. However, there is a problem that the threshold value α _n is reflected and the effect continues even after the signal duty returns to normal, resulting in erroneous determination.

The present invention has been made to solve such a problem, and when an abnormal signal duty occurs, it is not reflected in the calculation of the threshold value, so that the cylinder can be swiftly and accurately extracted at the time of extraction from the abnormal signal duty. An object of the present invention is to obtain a cylinder identification device for an internal combustion engine that can perform identification.

[Means for Solving the Problems] A cylinder identification device for an internal combustion engine according to the present invention generates a signal indicating predetermined first and second reference positions corresponding to each cylinder in synchronization with the rotation of the engine, A cylinder identification device for an internal combustion engine, which identifies a cylinder from an output signal of a rotation signal generator in which only a specific cylinder has a second reference position offset,
The calculation means for calculating the ratio value of the periods of the first and second reference positions with respect to the cycle of the reference position, and the calculating means for calculating a predetermined threshold value based on the calculated ratio value, A comparison means for comparing with the threshold value,
Cylinder identification means for identifying the cylinder based on the comparison result of the comparison means, and calculation prohibition means for preventing the current ratio value from being reflected in the calculation of the threshold value when the current ratio value becomes an abnormal value. It is equipped with.

[Operation] In the present invention, if the value of the current ratio calculated by the calculation means becomes an abnormal value, the current value of the ratio is not reflected in the calculation of the threshold value.

[Embodiment] FIG. 1 is a schematic configuration diagram of a cylinder identification device for an internal combustion engine according to an embodiment of the present invention. In the figure, (8) and (9) are the same as the conventional one. Reference numeral (10A) is a microcomputer including a computing means (11), a comparing means (12) and a cylinder identifying means (13).

FIG. 2 is a diagram showing a flowchart of the cylinder identification routine of the present invention.

In the cylinder identifying device for an internal combustion engine configured as described above, the cylinder identifying operation will be described with reference to the flowchart of FIG. The microcomputer (10) shown in FIG.
Rotation signal generator (8) to interface circuit (9)
The value of the "high level" output period (t) and the rising section period (T) of the signal is calculated by the calculating means (11) based on the signal transmitted via the signal (Fig. 2) (step S1). Then, in step S2, the ratio t / T is calculated by the above-mentioned calculating means (11) for each cylinder from t and T obtained in step S1. Next, in step S3, it is judged by the comparison means (12) whether the ratio t / T is within the specified range.
If t / T is outside the specified range, the current ratio t / T is calculated in step S7.
Is the specified value. That is, step S7 is the current ratio
When the value of t / T becomes an abnormal value, a calculation prohibiting unit is configured to prevent the current value of the ratio t / T from being reflected in the calculation of the threshold value αn. Then, the process proceeds to step S3, and the average threshold value [α _n = (1-k) α _n-1 + k (t / t
T) _n ] is calculated by the calculating means (12).

On the other hand, if t / T is within the specified range, the above-mentioned average threshold value α _n is calculated by the calculating means (12) from the value of the current ratio t / T. Step S4 and Step S5
Takes the same operation as in the prior art, and compares the ratio value for each cylinder obtained as described above with the average threshold value α _n (step S4). If the determination result is large, it is identified as a specific cylinder, and in this case, the # 1 cylinder is identified,
A flag is set in the register corresponding to the # 1 cylinder (step S5). If the judgment result is small, the process returns. In this way, when the specific cylinder is identified, the specific cylinder is the # 1 cylinder in this case. Therefore, when the # 1 cylinder is identified, the rotation signals are output in the order of # 1 cylinder → # 3 cylinder → # 4 cylinder → # 2 cylinder. Since it is obtained, the other cylinders can be sequentially identified in the order of # 3 cylinder → # 4 cylinder → # 2 cylinder.

As described above, the above cylinder identification can be accurately determined because the signal duty is not reflected in the calculation of the average threshold value even if the signal duty ratio becomes an abnormal value due to the rotational fluctuation rate of the engine.

[Effects of the Invention] As described above, according to the present invention, a signal indicating predetermined first and second reference positions corresponding to each cylinder is generated in synchronization with the rotation of the engine, and only the specific cylinder has the second reference position. A cylinder discriminating apparatus for an internal combustion engine for discriminating a cylinder from an output signal of a rotation signal generator having an offset, wherein a value of a ratio of a period of a first reference position to a period of a first reference position is calculated. Cylinder identification for calculating and calculating a predetermined threshold value based on the calculated ratio value, comparing means for comparing the current ratio value with the threshold value, and identifying a cylinder based on the comparison result of the comparing means. Since the means and the prohibition means for preventing the current value of the ratio from being reflected in the calculation of the threshold value when the current value of the ratio becomes abnormal, it is possible to judge whether the ratio t / T is abnormal. To do Therefore, even if an abnormality should occur, it is possible to minimize the misidentification of cylinders.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a cylinder identification device for an internal combustion engine according to an embodiment of the present invention, FIG. 2 is a flow chart of a cylinder identification routine of the present invention, and FIG. 3 is a structural diagram of a conventional rotation signal generator. FIG. 4 is a signal processing circuit diagram of a conventional rotation signal generator, FIG. 5 is a signal waveform diagram of a conventional rotation signal generator, and FIG. 6 is a schematic block diagram of a cylinder identification device of a conventional internal combustion engine. FIG. 7 is a flowchart of a conventional cylinder identification routine. In the figure, (1) ... rotation axis, (2) ... rotation plate,
(3), (3 ') ... Window, (4) ... Light emitting diode,
(5) ... Photodiode, (8) ... Rotation signal generator, (9) ... Interface circuit, (10A) ... Microcomputer, (11) ... Computing means, (12) ...
Comparison means, (13) ... Cylinder identification means. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A rotation signal generation in which a signal indicating predetermined first and second reference positions corresponding to each cylinder is generated in synchronism with rotation of an engine, and a rotation signal is generated by offsetting the second reference position only in a specific cylinder. A cylinder identification device for an internal combustion engine, which identifies a cylinder from an output signal of the engine, the first and second cylinders corresponding to a cycle of the first reference position.
Calculating means for calculating the ratio value of the reference position period and calculating a predetermined threshold value based on the calculated ratio value; and comparing means for comparing the current ratio value with the threshold value. Cylinder identification means for identifying a cylinder based on the comparison result of the comparison means, and prohibition of calculation so as not to reflect the current ratio value in the calculation of the threshold value when the current ratio value becomes an abnormal value And a cylinder identification device for an internal combustion engine.