JPH02223651A - Cylinder discriminating device for internal combustion engine - Google Patents

Abstract

PURPOSE:To discriminate a specified cylinder by means of a signal from one system by a method wherein in linkage of rotation of an engine, a signal by means of which given first and second reference position corresponding to respective cylinders are indicated is generated, and a rotation signal generator by which the second reference position of only the specified cylinder is offset is provided. CONSTITUTION:A rotation signal generator 8 has a window 3' for discriminating a specified cylinder being positioned asymmetrically to a window 3 for discriminating other cylinder and is provided with a rotary plate 2 to provide a signal from one system. A microcomputer 10 calculates a 'high level' period (t) and a rise section period T of a signal based on a signal outputted through an interface circuit 9 from the generator 8 and calculates a ratio t/T regarding each cylinder, and calculates threshold value alphan being an average of a ratio to compare the two values with each other. When a deciding result is high, it is discriminated that a cylinder is a specified one (No.1 cylinder). A cylinder used for regulation of an initial ignition timing is set such that setting to other cylinder is effected since the specified cylinder offsets the second reference position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cylinder identification device for an internal combustion engine that identifies cylinders from one system of signals from a one-rotation signal generator.

[Prior Art] In order to control ignition timing, fuel injection, etc. of an internal combustion engine, a signal synchronized with the rotation of the engine is used.

This signal generator usually detects the rotation of the engine's camshaft or crankshaft. An example of such a rotation signal generator is shown in FIGS. 4 and 5.

In the figure, (1) is a rotary shaft that rotates in synchronization with the engine (not shown), and 2) is a rotating disk attached to the rotary shaft (1), which has a window at a location corresponding to the desired detection angle. (3) is provided. (4) is a light emitting diode (5) is a photodiode that receives the output light from the light emitting diode (4), and (6) is connected to the photodiode (4) and amplifies the output signal of the photodiode (4). amplifier circuit,
(7) is an open collector output transistor connected to the amplifier circuit (6).

The rotation signal generator outputs two types of signals as shown in Fig. 6.1 The crank angle reference signal (SGT) shown in Fig. 6(b) is a signal that is inverted at a predetermined crank angle for each cylinder. and is used as a reference signal for crank angle. The cylinder identification signal (SGC) shown in FIG. 6(a) is #1
A signal is output when a cylinder signal is generated, and is used to identify the #1 cylinder.

In particular, it is possible to detect the timing of a specific cylinder (#1 in FIG. 5) using this cylinder identification signal (SGC), and perform cylinder-specific control for all cylinders in the above-mentioned control. In addition, as shown in Fig. 7, a rotation signal generator (8)
The output signal is inputted to a microcomputer (10) via an interface circuit (9) and used for control calculations of ignition timing, fuel injection, etc.

[Problems to be Solved by the Invention] In the conventional internal combustion engine cylinder identification device as described above, the crank angle reference signal (SGT) and the cylinder identification signal (SGC
), it is necessary to generate two systems of signals in the rotation signal generator, which poses a problem in that the configuration becomes complicated and the cost increases.

The present invention was made to solve this problem, and uses a single signal system to obtain a signal that includes both functions of a crank angle wide standard signal and a cylinder identification signal, and to identify a specific cylinder from that signal. The purpose is to obtain an engine cylinder identification device.

[Means for Solving the Problems] A cylinder identification device for an internal combustion engine according to the present invention generates signals indicating predetermined first and second reference positions corresponding to each cylinder in synchronization with the rotation of five engines, 1. A cylinder identification device for an internal combustion engine, which includes a rotation signal generator in which the second reference position is offset only for a specific cylinder, and identifies a cylinder from an output signal of the rotation signal generator, the apparatus comprising: 1 the first reference position; The value of the ratio of the periods of the first and second reference positions to the period of This avoids setting a cylinder as a cylinder used for initial ignition timing adjustment.

[Function] In this invention, the two-rotation signal generator has I! A signal indicating predetermined first and second reference positions corresponding to each cylinder is generated in synchronization with the rotation of the leaper, and the second reference position is offset for only one specific cylinder.

[Embodiment] FIG. 1 is a diagram showing the structure of a rotation signal generator of a cylinder identification device for an internal combustion engine according to an embodiment of the present invention. In the figure, the window (3') for identifying a specific cylinder is asymmetrical with the window (3) for identifying other cylinders, and is provided on the 9-rotary plate (2), so that signals can be obtained from one system. is the same as the conventional one shown in FIG.

FIG. 2 is a signal waveform obtained from the rotational signal generator of FIG.

FIG. 3 is a diagram showing a flowchart of the cylinder identification routine of the present invention.

In the cylinder identification device for an internal combustion engine configured as shown in E, the rise of the signal shown in Fig. 2 (75° - before top dead center)
BTDC75°) is used as the reference angle for control. Also, the second
The falling signal shown in the figure.

BTDC5 for other cylinders (#2 cylinder, #3 cylinder, #4 cylinder)
, and set the specific cylinder (#1 cylinder) to the retarded side by 10
° off-cent (Top dead center tlk 5°). The signal to be controlled is the rising edge of the signal shown in Figure 2 (BTDC75).
The basic method is to calculate the ignition timing based on °) (no problems occur because the same timing can be detected for all cylinders)
, and when cranking one engine, the ignition occurs at the falling edge of the signal shown in Figure 2. In this case, the specific cylinder is retarded by 100 compared to the other cylinders, but since it is on the retarded side, starting failure due to premature ignition does not occur.

Next, the cylinder identification operation will be explained using the flowchart shown in FIG. The microcomputer (10) shown in FIG.
of the signal based on the signal sent out through the
Calculate the "high level" output period (1) and rising period period (T) (step 51). Next, step S
Based on t and T obtained in step 1, in step S2, the "high level" is determined for the rising interval period (T) of the signal in FIG.
The ratio t/T of the output period (1) is calculated for each cylinder. Next, in step S3, an average threshold value [α,=(1-k)α7-
1tk (t/T). ] Calculate. Here, is a constant,
t, /T>α>t, /T.

The ratio value for each cylinder obtained as described above is compared with the average threshold value α (step 54). If the 0 judgment result is large, it is identified as a specific cylinder, and in this case, the #1 cylinder is A flag is set in the register corresponding to cylinder #1 (step 55).8 If the determination result is small, return (step S6).In this way, when the specific cylinder is identified, in this case, the specific cylinder is #1.
Since it is a cylinder, when identifying #1 cylinder, #1 cylinder → #
Since rotation signals are obtained in the order of the 3rd cylinder, the #4 cylinder, and the #2 cylinder, the other cylinders can be identified in the order of the #3 cylinder, the rival #4 cylinder, and the #2 cylinder.

On the other hand, a case where initial ignition timing adjustment is performed will be described. The purpose of this initial ignition timing adjustment is to set the cylinder at the correct position in order to obtain a reference for ignition timing control. Therefore, the specific cylinder identified in this way (in this case, #1-5) has the second reference position offset, so if it is set as the cylinder used for the initial ignition timing m-s, it will be set to the normal position. Because I can't.

It is not possible to obtain accurate standards for ignition timing control.

Therefore, the setting of the cylinder used for the initial ignition timing 1iJfi avoids one specific cylinder. in this case.

Cylinder #1 is set to another cylinder so as not to be used for initial ignition timing adjustment.

In addition, since the above-mentioned ki-a identification is performed by comparing the size based on the ratio of t/T, accurate judgment can be made even if rotational fluctuation occurs.

[Effect of the Invention 1] As explained above, this invention determines the magnitude relationship between a specific cylinder (cylinders other than the initial ignition timing Pi adjustment cylinder) and other cylinders with respect to the signal duty ratio with respect to the signal generation cycle of the cylinder monthly response. By doing so, in the method of identifying a specific cylinder from one system of rotational signals, it is possible to perform accurate cylinder identification and to perform accurate ignition timing control.

[Brief explanation of the drawing]

], r2 is a structural diagram of a rotation signal generator of a cylinder identification device for an internal combustion engine according to an embodiment of the present invention, FIG. 3 is a flowchart 1-1''I of the cylinder identification routine of the present invention, FIG. 4 is a structural diagram of a conventional rotation signal generator, and FIG. 5 is a signal processing circuit diagram of a conventional rotation signal generator.
Fig. 6 is a signal waveform diagram of the conventional rotation (No. 3 generator), and Fig. 7 is a schematic block diagram of a cylinder identification device for an internal combustion engine. Rotating plate, (3), (3')...window, (4)...light emitting diode, (5)...photodiode.In addition, the same reference numerals in each figure indicate the same or equivalent parts. Shown.

Claims (1)

[Claims] The engine includes a rotation signal generator that generates signals indicating predetermined first and second reference positions corresponding to each cylinder in synchronization with the rotation of the engine, and offsets the second reference position only for a specific cylinder. A cylinder identification device for an internal combustion engine that identifies cylinders from an output signal of a rotational signal generator, wherein the ratio of the periods of the first and second reference positions to the period of the first reference position is determined for each cylinder. A specific cylinder is identified by determining the ratio value for each cylinder and a predetermined value, thereby avoiding setting the identified specific cylinder as the cylinder used for initial ignition timing adjustment. Cylinder identification device for internal combustion engines.