JPH1151816A - Simple monitoring device of engine state - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the accurate detection of torque corresponding to the location of a crankshaft in a simple method by providing a torque detecting means, etc., to detect the shaft torque of the both sides of the crankshaft of an engine with a plurality of cylinders. SOLUTION: Rotation detectors 1A and 1B detect the turning angles of the both sides (open side and load side) of the crankshaft 11 of an engine 10 with a plurality of cylinders, and their output is connected to a phase difference computing unit 2. The phase difference computing unit 2 finds the helix angles of the crankshaft 11 on the basis of the phase differences of the rotation detectors 1A and 1B to compute shaft torque. The rotation detectors 1A and 1B and the phase difference computing unit 2 constitute a torque detecting means. On the basis of the shaft torque and through the use of a correction function set in advance, a torque correcting circuit 3 performs correction to obtain torque corresponding to the longitudinal location of the crankshaft 11 or the location of each cylinder. A comparator circuit 5 compares the waveform of the corrected torque with the waveform of torque observed in advance at normal times and determines anomaly when their difference exceeds a predetermined range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a simple state monitoring device for an engine for easily monitoring the state of the engine.

[0002]

2. Description of the Related Art An engine testing apparatus disclosed in Japanese Patent Application Laid-Open No. 60-256029 rotates a motor and rotates a crankshaft of the engine at a constant speed. A torque measuring apparatus drives the motor by the amount of electric power of the motor. The change in torque and the average value of this torque are measured.

[0003]

However, in the above-described conventional apparatus, since the shaft torque of the entire crankshaft is detected, even if there is an abnormality in any one of the cylinders, the amount of change is small, so that the accuracy is small. Could not monitor the condition of the engine. Further, since the engine is rotated by the motor, the actual torque generated by the engine cycle cannot be monitored.

[0004] It is an object of the present invention to provide a simple engine monitoring device capable of accurately knowing the torque corresponding to the position of the crankshaft by a simple method.

[0005]

In order to solve the above-mentioned problems, a first aspect of the present invention is a torque detecting means for detecting shaft torque on both sides of a crankshaft of an engine having a plurality of cylinders, and the torque detecting means. A torque correction means for correcting to a torque corresponding to the longitudinal position of the crankshaft or the position of each of the cylinders using a preset correction function based on the shaft torque detected by the engine. It is a monitor device.

According to a second aspect of the present invention, in the engine simple state monitoring device according to the first aspect, the torque detecting means detects a rotation angle on both sides of a crankshaft of the engine, and the rotation detector. And a phase difference calculator for calculating the phase difference of the rotation angle detected by the detector.

[0007] The third aspect of the present invention is the first or second aspect.
In the simplified state monitoring device of the engine described in
The above-mentioned torque correction means is a simple state monitoring device for an engine, wherein the correction is performed by a function including at least the position of the cylinder.

[0008] The invention of claim 4 is the first to third aspects of the present invention.
In the simplified state monitoring device for an engine described in any one of the above, the torque correction means may include a torque value theoretically obtained from the structure of the engine on the crankshaft, and a torque value on both sides of the crankshaft. A simple state monitoring device for an engine, wherein correction is performed by a function obtained from a ratio with a measured torque value.

[0010] The invention of claim 5 is the invention of claims 1 to 3.
The engine simplified state monitoring device according to any one of the preceding claims, further comprising an averaging means for averaging the output from the torque correction means.

[0010] The invention of claim 6 is the first to third aspects of the present invention.
The simple state monitoring device for an engine according to any one of the preceding claims, further comprising a comparison means for comparing an output from the torque correction means with a torque value in a normal state stored in advance. It is a state monitoring device.

[0011]

Embodiments of the present invention will be described below in more detail with reference to the drawings. 1 and 2 are views showing an embodiment of an engine simple state monitoring device according to the present invention. FIG. 1 is a block diagram,
FIG. 2 is a waveform chart for explaining the operation. The engine simple state monitoring device of this embodiment includes a rotation detector 1, a phase difference calculator 2, a torque correction circuit 3, an averaging circuit 4, a comparator circuit 5, and the like.

The rotation detector 1 (1A, 1B) is for detecting the rotation angle on both sides (open side and load side) of the crankshaft 11 of the engine 10. For example, the rotation detector 1 (1A, 1B) A device that generates a pulse electromagnetically or optically based on the rotation angle is used, and its output is connected to the phase difference calculator 2.

The phase difference calculator 2 includes rotation detectors 1A and 1B
The torsion angle of the crankshaft 11 is obtained based on the phase difference of
The output is connected to a torque correction circuit 3 for calculating the torque. These rotation detectors 1
And the phase difference calculator 2 constitute a torque detecting means.

The torque correction circuit 3 corresponds to the longitudinal position of the crankshaft 11 or the position of each cylinder using a preset correction function f based on the shaft torque detected by the phase difference calculator 2. This is a circuit for correcting the torque.

Next, a processing method of the correction circuit 2 will be described with reference to FIG. When the torsion angle is detected by the phase difference calculator 2 based on the rotation angles from the rotation detectors 1A and 1B, as shown in FIG. 2A, even if the explosive powers in the individual cylinders Cyl1 to Cyl4 are equal. In addition, the twist of the crankshaft 11 due to the explosion of the cylinder on the load side of the engine 10 is small, and the open side appears large. Note that the order of the explosions differs depending on the structure of the engine 10.

On the other hand, how the explosion of the cylinders Cyl1 to Cyl4 affects the torsion angle depends on the mechanical positions L1 to L4.
It can be obtained as a function including L4. Therefore, correction functions f (L1) to f (L4) are prepared in advance, and weighted according to changes in individual in-cylinder pressures, for example, as shown in FIG. The torque waveform a shown in FIG.
Is converted into a torque waveform b corresponding to the cylinder position.

The torque correction circuit 3 corrects the torque waveform a like a torque waveform b, that is, a circuit that corrects the torque waveform a to a value that originally corresponds to the force (torque) generated by each of the cylinders Cyl1 to Cyl4. It is. Each cylinder Cy
11 to Cyl4 can determine how much force is being generated based on the in-cylinder pressure of the explosion [FIG. 2 (C)]. At this time, the cylinders Cyl1 to Cyl4 are
Since they are not moving independently but are moving in an overlapping manner, consider a torque waveform obtained by adding four torque waveforms in which the timing of each cylinder is shifted. This torque waveform is calculated back (corresponding to the distance to each cylinder), corresponding to the position of the crankshaft 11 (position to each cylinder).
What is necessary is just to find the corrected correction function f, multiply it by the measured torque and correct it.

Further, since the torque can be obtained by the formula of torque = torsional rigidity × torsional angle, rigidity changes as the distance changes. If the torque is the same, the longer the distance, the easier it is torsion.Conversely, considering this in reverse, a correction function that increases the magnification closer to the load side and decreases the magnification farther away from the engine, It is also possible to calculate or measure according to the specification and store it in a memory, and generate data while multiplying the correction function f for each rotation.

As described above, since the method of converting the torque waveform a to the torque waveform b can be obtained theoretically or by actual measurement, each point of one rotation or two rotations (720 °) can be obtained. The correction data can be stored as a memory and multiplied for each point. Specifically, the number of pulses generated in one rotation of the rotation detector 1 is sampled, and when one screen frame of the monitor is 1024 points, what kind of coefficient is given for each point is determined. For example, since data (torsion angle) from the phase difference calculator 2 is input at a fixed timing for each rotation pulse, correction may be performed based on the value.

The torque correction circuit 3 obtained as described above
Is connected to the averaging circuit 4 and the comparator 5. The averaging processing circuit 4 is a circuit that averages and calculates the torque of the crankshaft. By averaging the torque, the torque of the engine 10 can be monitored. Output horsepower etc. can be obtained.

The comparator circuit 5 includes a torque correction circuit 3
Is compared with a torque waveform measured in advance when the engine is normal, and when the difference is out of a predetermined range [see the part d in FIG.
Abnormalities such as connecting rod metal abnormality and piston ring abnormality can be detected.

(Modifications) Various modifications and changes are possible without being limited to the above-described embodiment, and are within the scope of the present invention. In this embodiment, the correction function has been described as a function of only the distances L1 to L4 for simplicity. But for the exploding cylinder,
Since the other cylinders are affected, the load will be different. To correct this, it is desirable to consider not only the position function but also the load function. It is also desirable to consider the compression accompanying the order of the explosions and the state before and after the compression.

[0023]

As explained in detail above, the present invention provides:
Since the torque measured on both sides of the crankshaft is corrected to a torque corresponding to the position of the crankshaft or the cylinder position using a correction function set in advance, the state (torque) of each part of the engine is easily and accurately monitored. This has the effect of being applicable to various abnormality diagnoses.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a simplified state monitoring device for an engine according to the present invention.

FIG. 2 is a waveform diagram showing a processing operation of the engine simple state monitoring device according to the embodiment.

[Explanation of symbols]

 Reference Signs List 1 electromagnetic rotation detector 2 phase difference calculator 3 torque correction circuit 4 averaging processing circuit 5 comparator circuit

Claims (6)

[Claims] 1. A torque detecting means for detecting shaft torque on both sides of a crankshaft of an engine having a plurality of cylinders, and a correction function set in advance based on the shaft torque detected by the torque detecting means. A simple state monitoring device for an engine, comprising: torque correction means for correcting a torque corresponding to a position in a longitudinal direction of the crankshaft or a position of each of the cylinders. 2. The simplified state monitoring device for an engine according to claim 1, wherein the torque detecting means detects a rotation angle on both sides of a crankshaft of the engine, and the rotation detector detects the rotation angle. A simple state monitoring device for an engine, comprising: a phase difference calculator for calculating a phase difference between rotation angles. 3. The simple state monitor of the engine according to claim 1, wherein the torque correction means corrects the torque using a function including at least a position of the cylinder. Monitor device. 4. The simplified state monitoring device for an engine according to claim 1, wherein the torque correction unit is theoretically obtained from a structure of the engine on the crankshaft. A simple state monitoring device for an engine, wherein the correction is performed by a function obtained from a ratio between a torque value and torque values actually measured on both sides of the crankshaft. 5. The simple state monitoring device for an engine according to claim 1, further comprising an averaging means for averaging an output from said torque correction means. A simple engine status monitor. 6. A simple state monitoring device for an engine according to claim 1, wherein an output from said torque correction means is compared with a previously stored normal torque value. A simple state monitoring device for an engine, characterized by comprising means.