JPH04216433A - Inspecting method of internal combustion engine - Google Patents

Abstract

PURPOSE:To inspect an internal combustion engine correctly by reducing influences of the external disturbance such as electric noises or the like. CONSTITUTION:A cylinder judging sensor 2 generates one pulse for every one cycle of an engine 1. A rotating number detecting sensor 4 generates an output of a waveform signal as the tooth of a ring gear 3 pass. A rotating number calculating circuit 6 counts the number of pulse signals from a pulse generator 5 in a very small interval of waveform signals, thereby calculating the rotating speed. A microcomputer 7 sequentially takes and allots the rotating speed of the very small interval while the engine 1 rotates one cycle to each cylinder and obtains the average value. The microcomputer 7 obtains the difference of the average value of the rotating speed of the cylinder exploding now and the average value of the rotating speed of the cylinder exploding last time. When the difference is smaller than a set value, an abnormality indicating lamp 9 is turned ON by the microcomputer 7.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting the operating performance of an internal combustion engine during a bench test after assembly.

0002

2. Description of the Related Art Conventionally, as a method for inspecting the operating performance of a multi-cylinder engine for each cylinder, for example, Japanese Patent Laid-Open No. 57-591
There is one disclosed in Publication No. 38. In this method, the engine rotation speed is determined, the minimum value of the engine rotation speed near the explosion start time of each cylinder is determined from the same rotation speed data, the difference between the minimum values corresponding to each cylinder is determined, and the difference is calculated based on this difference. This is to check the rotation of the engine.

0003

[Problems to be Solved by the Invention] However, since the conventional inspection method uses only the minimum value of the engine rotation speed, when electrical noise is superimposed on the output signal of the engine rotation speed detection sensor, it is difficult to determine the minimum value of the electrical noise. There was a risk that the value would be detected as the rotational speed, leading to a misjudgment.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide an internal combustion engine inspection method that can reduce the influence of disturbances such as electrical noise and make accurate judgments. be.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the internal combustion engine inspection method of the present invention detects the rotational speed of an internal combustion engine having multiple cylinders in a minute time, and also detects which cylinder of the internal combustion engine is detected. Detects whether it is in the process of explosion,
Calculate the average value of the rotational speed during the explosion stroke of each cylinder,
The difference between the average value of the rotational speed of the cylinder that exploded this time and the average value of the rotational speed of the cylinder that exploded last time was calculated, and if the difference between the average values fell outside a predetermined range, it was determined that there was an abnormality.

[0006]

[Operation] In the inspection method of the present invention, first, the rotational speed of the internal combustion engine in a minute time is detected, and which cylinder is in the explosion stroke is detected. Next, the average value of the rotational speed during the explosion stroke of each cylinder is calculated. After calculating the average value, the average value of the rotational speed of the cylinder that exploded this time is compared with the average value of the rotational speed of the cylinder that exploded last time. If the difference between the average values is out of a preset range, it is determined that there is an abnormality. Therefore, even if electrical noise is superimposed when detecting the rotational speed, calculating the average value of the rotational speed, etc., the electrical noise will be averaged when calculating the average value. Therefore, the influence of electrical noise on the rotational speed becomes negligible.

[0007]

[Example] Hereinafter, an example embodying the present invention is shown in Figs.
This will be explained according to FIG. FIG. 1 is a diagram showing a schematic configuration of an inspection device and an internal combustion engine used to perform this inspection method. This internal combustion engine is an engine 1 having multiple cylinders, and in this embodiment, the engine 1 is a 4-stroke in-line 6
A cylinder engine is used. As is well known, in this engine 1, intake, compression, explosion, and exhaust strokes are performed for each cylinder, and one cycle is completed by these four strokes. During the four strokes, the piston moves up and down twice,
The crankshaft also rotates twice. Further, ignition is performed every 1/3 rotation of the crankshaft, that is, every 120° rotation. Note that if the six cylinders are numbered 1 to 6 in order, the firing order is 3-6-5-1-2- in this example.
It is 4.

A cylinder discrimination sensor 2 is attached to the engine 1. As the cylinder discrimination sensor 2, for example, a cam angle sensor that detects the rotation angle of a cam is used. The cylinder discrimination sensor 2 generates one pulse every time the engine 1 performs one cycle (every two rotations of the crankshaft), as shown by the cylinder discrimination signal in FIG. Further, a flywheel is fixed to the rear end of the crankshaft of the engine 1 (the right end in the figure), and a ring gear 3 having 120 teeth is attached to the outer periphery of the flywheel.

[0009] A rotation speed detection sensor 4 consisting of an electromagnetic pickup or the like is attached near the ring gear 3. This rotation speed detection sensor 4 utilizes the characteristic that the inductance of the coil changes when the position of the iron piece (in this case, the teeth of the ring gear 3) changes.When the ring gear 3 rotates, the rotation speed detection signal shown in FIG. A waveform (sine wave) signal corresponding to the passage of the teeth of the ring gear 3 is output. In FIG. 2, one period of the waveform corresponds to one tooth of the ring gear 3.

The rotation speed detection sensor 4 and the pulse generator 5 are connected to a minute section rotation speed calculation circuit 6. The pulse generator 5 regularly generates pulses as shown by the pulse signal in FIG. The minute section rotation speed calculation circuit 6 counts the number of pulse signals generated in a minute section (one period of the same detection signal) in the detection signal from the rotation speed detection sensor 4, and calculates the rotation speed of the minute section from this counted number. Calculate.

The minute section rotation speed calculation circuit 6 and cylinder discrimination sensor 2 are connected to the input side of a microcomputer (hereinafter simply referred to as microcomputer) 7. Furthermore, a normality indicator lamp 8 and an abnormality indicator lamp 9 are connected to the output side of the microcomputer 7. The microcomputer 7 determines the malfunctioning cylinder based on the output signals from the minute section rotation speed calculation circuit 6 and the cylinder discrimination sensor 2, and generates a control signal for lighting the normality indicator lamp 8 or the abnormality indicator lamp 9 based on the determination result. Output.

Next, the operation of this embodiment will be explained according to the flowchart of FIG. When the engine 1 is started and is in an idling state, when the inspection device is turned on, the microcomputer 7 takes in the signal from the cylinder discrimination sensor 2 in step 101, and the engine 1 starts one cycle using this signal as a starting point. The number of pulses, that is, the rotational speed, in minute intervals during the period up to this point (until the crankshaft rotates twice) is sequentially captured, and a total of 240 pulses are captured in one cycle.

Next, in step 102, the microcomputer 7 determines the order of explosion cylinders (3-6-5-1-2-4) of the engine 1;
Based on the output signal from the cylinder discrimination sensor 2, each rotation speed in 240 minute intervals is assigned to each cylinder. That is, since the present embodiment is a six-cylinder engine 1, 40 minute sections of rotational speed are assigned to each cylinder.

[0014] Then, the microcomputer 7 moves to step 103, and calculates the (additive) average value Ai (A3, A6 , A5, A1, A2, A4
). After calculating the average rotational speed Ai in each minute section, the microcomputer 7 in step 104 determines the difference Si (for example, S6=A6 -A3,S5=
A5-A6) is obtained, and the process moves to step 105. Note that the difference Si between the average values is an absolute value.

In step 105, the microcomputer 7 compares the average difference Si obtained in step 104 with a preset value α. If the average difference Si is smaller than the set value α, the microcomputer 7 determines that the engine 1 is operating normally, and outputs a control signal to turn on the normality indicator lamp 8 in step 106. the result,
The normality indicator lamp 8 lights up to notify the user. Also,
If the difference Si between the average values is greater than or equal to the set value α, the microcomputer 7 determines that the operating state of the engine 1 is abnormal, and outputs a control signal to turn on the abnormality indicator lamp 9 in step 107. . After executing step 106 or 107, the microcomputer 7 ends this routine.

In this way, in this embodiment, the rotational speed of the engine 1 in a minute time is detected, and which cylinder of the engine 1 is in the explosion stroke is detected, and the average rotational speed of each cylinder during the explosion stroke is determined. The value Ai is being calculated. That is, in this embodiment, the average value of 40 minute intervals is used as the rotation speed of each cylinder. Then, the difference Si between the average value of the rotational speed of the cylinder that exploded this time and the average value of the rotational speed of the cylinder that exploded last time is calculated, and if the difference Si between the average values becomes more than a preset value α, it is determined that there is an abnormality. I made it.

Therefore, even if electrical noise is superimposed on the output signal of the rotational speed detection sensor 4 or the signal from the minute section rotational speed calculation circuit 6, the electrical noise will be reduced to the average value A of the rotational speed.
When calculating i, it is averaged. That is, even if electrical noise is included in the output signal of the rotational speed detection sensor 4, as shown by the dashed line in FIG. 2, for example, it is canceled out by averaging the noise components, so that false detection will not occur. The same applies when electrical noise is superimposed on the minute section rotation speed calculation circuit 6. Therefore, the influence of electrical noise on the rotational speed becomes negligibly small, making it possible to accurately determine the operating performance of the engine 1.

It should be noted that the present invention is not limited to the configuration of the embodiment described above, and for example, instead of the normal indicator lamp 8 and the abnormal indicator lamp 9, an abnormal cylinder may be displayed on a CRT, or multiple cylinders other than 6 cylinders may be displayed. Any changes may be made without departing from the spirit of the invention, such as application to cylinder engine inspection.

[0019]

Effects of the Invention As described in detail above, according to the internal combustion engine inspection method of the present invention, the average value of the rotational speed during the explosion stroke of each cylinder is calculated, and the average value of the rotational speed of the cylinder that exploded this time and the previous one are compared. The difference between the rotational speed of the exploded cylinder and the average value is calculated, and if the difference in the average value falls outside of a predetermined range, it is determined to be abnormal.This reduces the influence of disturbances such as electrical noise and provides accurate This has an excellent effect of making it possible to make a judgment.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of an inspection device and an engine.

FIG. 2 is a diagram showing output signals of a cylinder discrimination sensor, a rotation speed detection sensor, and a pulse generator.

FIG. 3 is a flowchart for explaining the operation of the embodiment.

[Explanation of symbols]

1 Engine as an internal combustion engine, 2 Cylinder discrimination sensor, 4 Rotation speed detection sensor, 5 Pulse generator, 6
Micro section rotation speed calculation circuit, 7 microcomputer, Ai
Difference between average value of rotational speed and average value of Si

Claims (1)

[Claims] Claim 1: Detecting the rotational speed of an internal combustion engine having multiple cylinders in a minute time, detecting which cylinder of the internal combustion engine is in the explosion stroke, and calculating the average value of the rotational speed during the explosion stroke of each cylinder. The system calculates the difference between the average rotation speed of the cylinder that exploded this time and the average rotation speed of the cylinder that exploded last time, and if the difference between the average values falls outside a predetermined range, it is judged as abnormal. An internal combustion engine inspection method characterized by: