JPH0758232B2 - Internal combustion engine output calculation method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine output calculation method.

[0002]

2. Description of the Related Art In a conventional output calculation method for an internal combustion engine, a cylinder pressure (cylinder pressure) is measured by a pressure sensor to form a mountain-shaped curve as shown in FIG. Angle and cylinder pressure are plotted on the vertical axis, and the torque is calculated from the average effective pressure calculated based on the separately detected piston top dead center (hereinafter also referred to as TDC) position, and is the product of the engine speed at that time. Seeking output (indicator horsepower).
In the cylinder pressure diagram of FIG. 5, TDC (piston top dead center)
The left side A shows the power loss (necessary power for compression) side, and the right side B shows the output side, and the average effective pressure is obtained from the area difference between the two. Therefore, in this method, it is important to accurately detect the position of the piston top dead center in order to accurately calculate the output.

By the way, conventionally, in order to detect the position of the top dead center of the piston, an iron piece corresponding to the number of cylinders is theoretically attached to the flywheel on the output shaft of the engine from the crank angle.
It was fixed with a bolt at the top dead center position of the piston, which was decided by design, and an electromagnetic pickup was installed facing this.
Thereby, the iron top piece in the flywheel is detected to detect the piston top dead center position.

On the other hand, in order to measure the number of revolutions of the engine, a plurality of pins are embedded in the outer peripheral surface of the flywheel on the output shaft or the flywheel itself is machined into a gear shape in addition to the above-mentioned sensor. The unevenness was detected by an electromagnetic pickup or the like provided in confrontation with this, and the engine speed was measured based on the pulse signal obtained thereby. The pressure inside the cylinder is detected by a pressure sensor screwed into an indicator cock provided at the top of the cylinder.

[0005]

The above-mentioned conventional methods have the following problems.

In order to accurately detect the top dead center of the piston, a high degree of mounting accuracy of the iron piece is required. On the other hand, even if the mounting position of the iron piece is correct, when the load is actually applied, the output shaft is twisted so that the piston top dead center cannot be detected accurately, and therefore the output cannot be calculated accurately.

Since the flywheel needs to be machined into a gear for measuring the number of revolutions, the device cannot be constructed at low cost.

Since two sensors are required for detecting the engine speed and for detecting the piston top dead center, the number of sensors is large, which requires a lot of time and effort for mounting and complicates the apparatus.

Therefore, the present invention reduces the number of sensors,
It is an object of the present invention to provide a method that requires less mounting accuracy, can simplify the device, and can accurately calculate an engine output.

[0010]

In order to achieve the above object, the present invention is directed to a rotational speed information of an engine by a sensing plate mounted on an output shaft or a flywheel of an internal combustion engine and a detector provided opposite to the sensing plate. And temporary piston top dead center information is obtained, and at the same time, the pressure sensor inside the cylinder of the engine is used to obtain in-cylinder pressure information for a given crank angle, while the actual piston top dead center is detected in advance by fuel cut operation or turning. The deviation amount between the temporary piston top dead center and the actual piston top dead center due to the sensing plate is obtained, and the temporary piston top dead center position is shifted by this deviation amount to output the internal combustion engine in various operating states. Is a method for calculating the output of an internal combustion engine, which is characterized in that

[0011]

In the above structure, the engine speed and the temporary piston top dead center position are detected by the sensing plate and the detector, and the cylinder pressure is measured by the pressure sensor. And
A deviation amount between the actual piston top dead center detected by the fuel cut operation or the like and the temporary piston top dead center detected by the sensing plate is obtained. Based on this deviation amount, the operation of moving the above-mentioned temporary top dead center to the actual top dead center in the cylinder pressure curves at various load conditions and engine speeds makes it possible to obtain accurate engine output in various operating conditions. Is calculated. In such an output calculation method, since it is not necessary to mount the sensing plate with high accuracy, it is easy to mount, and the engine speed and the position of the piston top dead center (provisional) are detected with one sensing plate. This reduces the number of sensors and simplifies the overall device.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram according to an embodiment of the method of the present invention. On the output shaft 2 of an internal combustion engine (for example, a two-cycle engine as a marine engine) 1, a sensing plate 3 made of a reflective film, an iron piece, or the like is provided with a piston top dead center (based on a crank angle). A detector 4 such as a photoelectric switch (or an electromagnetic pickup) is provided at a position of (TDC) and faces the sensing plate 3. The sensing plate 3 and the detector 4 constitute a digital detector that detects the engine speed and the top dead center of the temporary piston. Further, the sensing plate 3 may be mounted at an approximate position of the output shaft 2 or the top dead center of the piston of the flywheel (in this sense, the sensing plate 3
The top dead center of the piston obtained by the above is referred to as the temporary top dead center of the piston), and since the accuracy is not required, the work of attaching the sensing plate 3 becomes easy. Therefore, since it can be easily mounted on the output shaft of the internal combustion engine of an existing ship (service ship), the application range of the present invention is wide. A cable 5 for electrically transmitting the pulse signal obtained by the detector 4 is installed from the detector 4 to the junction box 6.

On the other hand, a pressure detection pipe 8 for measuring the internal pressure of the cylinder 7 is connected to a pressure detection passage 8a formed in the cylinder head 7a. An indicator cock 9 is attached to the pressure detecting pipe 8, and a pressure sensor 10 is screwed into the indicator cock 9. The cable 11 to which the pressure information in the cylinder (which is a mountain-shaped curve as shown in FIG. 2) is to be electrically transmitted is connected to the pressure sensor, and is led to the above-mentioned connection box 6. The connection box 6 has a function of matching the voltage of the electric signal sent from the detector 4 with the voltage of the electric signal sent from the pressure sensor 10, and the cable 12 is led from the connection box 6 to the data recorder. The data of the pressure sensor 10 (cylinder pressure information) and the data of the detector 4 (engine speed information and temporary piston top dead center information) are recorded on the floppy disk set in the recorder 13. Has become. A power source is connected to the connection box 6.

Now, a method of detecting the engine speed and the temporary piston top dead center by the sensing plate 3 and the detector 4 will be described.
When the internal combustion engine 1 is operated, the output shaft 2 rotates, and the sensing plate 3 provided on the output shaft 2 also rotates. When the light emitted from the detector 4 hits the sensing plate 3, it is reflected and received by the detector 4. This is transmitted to the junction box 6 as a pulse signal as shown in FIG. 2 and input. Since only one sensing plate 3 is attached, one rotation of the engine is detected by the pulse signal P of the next sensing plate 3, and the time between both pulses is separately measured. The number is calculated.

Since the sensing plate 3 is mounted at the position of the piston top dead center of the cylinder, that is, at the crank angle of 0 ° from the crank angle, as described above, the detection of the sensing plate 3, that is, the above-mentioned The central part of the pulse is detected as a temporary (temporary) piston top dead center. However, this top dead center is usually different from the actual (true) piston top dead center.
Even if the sensing plate 3 is installed at the true piston top dead center position, when the propeller is rotated and a load is applied to the output shaft 2, the shaft is twisted. Therefore, the piston top dead center detected by the sensing plate 3 is actually It is slightly off the top dead center.

On the other hand, the data of the in-cylinder pressure detected by the pressure sensor 10 becomes a mountain-shaped curve (in-cylinder pressure diagram) C as shown in FIGS. However, since the piston top dead center detected by the sensing plate 3 is different from the actual one as described above, the accurate horsepower cannot be calculated based on this.

Therefore, in order to know the actual piston top dead center position, a fuel cut operation (or turning) operation is performed in advance to obtain a mountain-shaped cylinder pressure diagram C ₀ as shown in FIG. In the fuel cut operation, the cylinder has no explosive stroke and is only compressed, so the peak of the mountain gives the actual piston top dead center position. The data of the actual piston top dead center is recorded in the data recorder 13 in advance.

A microprocessor (personal computer) 14 collects information on the engine speed input to the data recorder 13, information on the temporary piston top dead center based on the sensing plate, and actual piston top dead center.
Then, the deviation amount (FIG. 4) between the actual piston top dead center and the temporary piston top dead center is calculated. Then, in order to match the tentative piston top dead center with the actual piston top dead center, the displacement is moved on the microprocessor 14 by this shift amount. As a result, the average effective pressure of the in-cylinder pressure is calculated by dividing the actual piston top dead center position into the power loss side A on the left side and the output side B on the right side, and the torque can be calculated. The output (indicator horsepower) is obtained by the product of this torque and the engine speed obtained above.

Engine operating condition (load condition, rotation speed, etc.)
Although the crest curve of the cylinder pressure differs depending on the above, it is considered that the amount of deviation between the top dead center and the actual top dead center due to the sensing plate does not change much in either case. After that, the processing can be automatically performed by the microprocessor 14 thereafter. Therefore, no further adjustments are necessary thereafter, which allows an almost accurate calculation of the engine power under various operating conditions.

[0021]

According to the method of the present invention as described above, the following effects can be obtained.

The output of the engine under various operating conditions can be calculated easily and almost accurately.

Since it is not necessary to consider the accuracy of the piston top dead center detector, it can be easily attached and adjusted.

Since the single sensing plate serves both as the piston top dead center detection sensor and the shaft rotation speed detection sensor, the device can be simplified.

The detector can be applied regardless of the type and arrangement of the engine or the shape of the output shaft.

Since only one sensing plate needs to be attached to the flywheel or the output shaft, it can be easily installed on an existing ship.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the method of the present invention.

FIG. 2 is a cylinder pressure diagram obtained by a pulse signal obtained by a digital detector and a pressure sensor in an actual operating state of an internal combustion engine.

FIG. 3 is a cylinder pressure diagram obtained by a fuel cut operation.

FIG. 4 is an explanatory diagram of a procedure for matching a temporary TDC with an actual TDC in an in-cylinder pressure diagram in an actual operating state of an internal combustion engine.

FIG. 5 is a cylinder pressure diagram.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Output shaft 3 ... Sensing plate 4 ... Detector 7 ... Cylinder 10 ... Pressure sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location G01M 15/00 Z (72) Inventor Yoshihiro Yamase 1 Kawasaki-cho, Sakaide-shi, Kagawa Kawasaki Heavy Industries Ltd. Sakaide Factory (56) References Japanese Patent Publication No. 51-44670 (JP, B2)

Claims (1)

[Claims] 1. An engine rotational speed information and temporary piston top dead center information are obtained by a sensing plate mounted on an output shaft or a flywheel of an internal combustion engine and a detector provided in opposition thereto, and at the same time, While the pressure sensor installed at the top of the cylinder obtains pressure information in the cylinder for a given crank angle,
The actual piston top dead center is previously detected by the fuel cut operation or turning, and the deviation amount between the temporary piston top dead center and the actual piston top dead center by the sensing plate is obtained.
A method for calculating the output of an internal combustion engine, wherein the output of the internal combustion engine in various operating states can be calculated almost accurately by shifting the position of the temporary piston top dead center by this shift amount.