JPH02211355A - Discrimination of cylinder for internal combustion engine - Google Patents

Abstract

PURPOSE:To surely discriminate each cylinder even in a system in which the relative position allowance is increased, by monitoring the output level of a cylinder discriminating signal in the output timing of a standard angular signal at each cylinder interval and discriminating the cylinder by detecting the variation of the level. CONSTITUTION:The N-signal as standard angular signal in rectangular wave pulse train which corresponds to the cylinder quantity of an internal combustion engine and the G-signal as cylinder discriminating signal in rectangular wave pulse which outputs each edge between the prescribed standard angular signals are used, and the output level of the G-signal is monitored with the output timing of the N-signal at each cylinder interval, and the cylinder is discriminated by detecting the variation of the level. Since the cylinder is discriminated from the variation of the output level of the G-signal between the relatively broad output timing at each cylinder interval of the N-signal, the cylinder can be surely discriminated without carrying out the precise management for the relative position even in the system in which the relative position allowance is increased by arranging a G-signal sensor onto a cam shaft and arranging an N-signal sensor onto a crankshaft.

Description

[Detailed Description of the Invention] C. Industrial Application Field] The present invention provides an angle sensor, for example, on the crankshaft of an internal combustion engine.
5. Install a cylinder discrimination sensor on the camshaft. The present invention relates to a cylinder discrimination method in the provided system.

[Conventional technology]

Conventionally, a number of rectangular wave reference angle signals (hereinafter N
As shown in FIG. The G signal was used to distinguish between cylinders by changing the signal width at a predetermined cylinder position.

[Problem to be solved by the invention]

However, in this method, if both the G and N signals are built into the housing of the distributor, etc.
The relative position of the sensor signal output was guaranteed by controlling the assembly accuracy inside the housing, but the
In a system where a G sensor is installed on a sensor or camshaft, it is important to manage the relative position because tolerance factors increase, such as the relative angle accuracy between the engine crank and the camshaft and the installation position accuracy of each sensor. The problem is that it is extremely difficult.

Therefore, the present invention provides a G signal format that can increase the allowable value for the relative positions of the G and N signals necessary for cylinder discrimination. The aim is to be able to satisfy even systems with wide positional tolerances.

[Means to solve the problem]

Therefore, the present invention uses a reference angle signal of a rectangular wave pulse train corresponding to the number of cylinders of an internal combustion engine and a cylinder discrimination signal of a rectangular wave pulse in which an edge is output between the predetermined reference angle signals. Another object of the present invention is to provide a cylinder discrimination method for an internal combustion engine, which monitors the output level of the cylinder discrimination signal at the output timing of the reference angle signal, detects a change in the level, and discriminates the cylinder.

Here, cylinder discrimination is preferably performed by using a cylinder discrimination signal whose output level is inverted every 360° crank angle, and based on changes in the output level.

Further, the cylinders can also be discriminated based on the number of consecutive output levels of the cylinder discrimination signal monitored for each cylinder.

[Effect]

Thereby, cylinder discrimination is performed based on a change in the output level of the cylinder discrimination signal during a relatively wide output timing of the reference signal for each cylinder interval.

〔Example〕

The present invention will be described below with reference to embodiments shown in the drawings.

In FIGS. 3 and 4, 1 indicates a six-cylinder internal combustion engine, 2 indicates a crankshaft of the internal combustion engine 1, and 3 indicates a camshaft. 3 and rotates at a crankshaft speed of 172. 5 is a reference angle signal (hereinafter abbreviated as N signal) sensor attached to the crankshaft 2, and as shown in FIG. If so, 2 revolutions of crankshaft 2 will result in 6
A pulse) is generated, and the generation position of the effective edge of the pulse (arrow in FIG. 1 et al.) is set to the reference position of each cylinder (for example, top dead center: TDC). 6 is a cylinder discrimination (hereinafter abbreviated as G signal) sensor attached to the camshaft 3, as shown in Fig. 1 (a).
), the high level (hereinafter referred to as H) during the 360'CA period during the 720°CA rotation of the crankshaft 2 (one cycle of the internal combustion engine)
The remaining 360'CA period is low level (hereinafter referred to as L).
A signal is generated. Also, #1 → 5 → 3 → 6 → 2 →
For example, take a 6-cylinder internal combustion engine that fires the 4 cylinders in sequence.
If the first valid edge of the N signal (falling edge in FIG. 1) after the rising edge of the G signal is taken as the TDC of the first cylinder, then
The configuration is such that the first valid edge of the N signal after the falling edge of the G signal becomes the TDC of the sixth cylinder. FIG. 5 is a flowchart of the processing performed within the microcomputer when determining the cylinder using the G signal and the N signal.

Next, the operation of the above configuration will be explained.

The cylinder discrimination method will be described using the flowchart shown in FIG. This processing is performed by interrupt processing every time the valid edge of the N signal is input manually. First, when the N signal is input, step 10 is passed. Next, in step 11, the flag FLG is read, which stores whether the G signal was high or not when the process in this flowchart was performed last time (Figure 1 (C) shows the state of the flag FLG). ). This flag FLG becomes 1 when the G signal is at the H level, and becomes 0 when the G signal is at the L level. If flag FLG=1, the process of step 12 is performed, and if FLG=O, the process of step 16 is performed. First, the process of step 12 will be explained. At this point, the G signal level is read, and if it is H level, it is set to FLG-1 in step 13. Step 12
If it is determined that the G signal is at the L level, the process proceeds to step 14 and is set to FLG-0, and in step 15 it is determined that the current N signal position is the TDC of the sixth cylinder. If it is the previous FLG-0 in step 11, the process advances to step 16. Here too, the current G signal level is read in the same way as in step 12. If the G signal level is high, FLG is set to 0 in step 17. Conversely, if it is H, FLG is set to 1 in step 18, and it is determined in step 19 that the current N signal position is the TDC of the first cylinder.

As described above, if the rising edge and falling edge of the G signal are between the valid edges of the N signal, that is, in the case of a 6-cylinder internal combustion engine, the cylinders can be identified. Therefore, even in systems with large relative positional tolerances, such as obtaining a cylinder discrimination signal from the camshaft and a reference angle signal from the crankshaft, the relatively permissible range of the G signal position is expanded, allowing accurate cylinder detection. It is possible to make a judgment.

In the above embodiment, the G signal sensor 6 is arranged on the camshaft 3, and the N signal sensor 5 is arranged on the crankshaft 2, but the present invention can also be applied to an arrangement in which both sensors 5 and 6 are arranged on the camshaft 3 side. is applicable.

Furthermore, although the above embodiments have been described with respect to a 6-cylinder internal combustion engine, the present invention is also applicable to other engines (4 cylinders, 8 cylinders, etc.).

In addition, using a cylinder discrimination signal (G signal) and a reference angle signal (N signal) as shown in Fig. 6, if the G signal is at H level when the N signal is input using a hard counter or soft counter CNT, the counter CN If the configuration is such that T is increased and O is set to L level, when the value of counter CNT is 1, it is the TDC of the first cylinder.

When the value of the counter CNT is 2, it is determined that it is the TDC of the 6th cylinder, and cylinder discrimination can be performed in the same manner as in the embodiment described above.

〔Effect of the invention〕

As described above, in the present invention, cylinder discrimination is performed based on changes in the output level of the cylinder discrimination signal during a relatively wide output timing of the reference signal for each cylinder interval.
Even in systems with large relative position tolerances, such as those in which a G signal sensor is placed on the camshaft and an N signal sensor is placed on the crankshaft, cylinder discrimination can be performed reliably without strict relative position management. It has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a signal waveform diagram in an embodiment of the method of the present invention, FIG. 2 is a signal waveform diagram in a conventional method, FIG. 3 is a block diagram showing an embodiment of a device to which the method of the present invention is applied, and FIG. 3 is a schematic configuration diagram of an internal combustion engine showing the installation state of the sensor in the illustrated device, FIG. 5 is a flowchart showing one embodiment of the method of the present invention, and FIG. 6 is a signal waveform in another embodiment of the method of the present invention. It is a diagram. 1... Internal combustion engine, 2... Crankshaft, 3... Camshaft. 5... Reference angle signal sensor, 6... Cylinder discrimination signal sensor. 7... Internal combustion engine control circuit. Figure 1 Figure 2 Figure 2

Claims (3)

[Claims] (1) Using a reference angle signal of a rectangular wave pulse train corresponding to the number of cylinders of the internal combustion engine and a cylinder discrimination signal of a rectangular wave pulse in which an edge is output between the predetermined reference angle signals, A cylinder discrimination method for an internal combustion engine, which monitors the output level of the cylinder discrimination signal at the output timing of the reference angle signal, detects a change in the level, and discriminates the cylinder. (2) The cylinder discrimination method for an internal combustion engine according to claim 1, wherein the cylinder discrimination signal is used to invert the output level every 360° crank angle, and the cylinder discrimination is performed based on the change in the output level. (3) The cylinder discrimination method for an internal combustion engine according to claim 1, wherein the cylinder discrimination is performed based on the number of times that the output level of the cylinder discrimination signal monitored for each cylinder remains at the same level.