JPH051630Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a diagnostic device for a turbomachine such as a turbocharger of a diesel engine or a gas turbine that rotates a turbine using combustion gas.

<Prior Art> A supercharger for a diesel engine, which is one of this type of turbomachine, is provided to increase the output per cylinder volume of the diesel engine and improve the fuel consumption rate and thermal efficiency. Exhaust turbine superchargers, which are driven by the engine's exhaust gas, have good mechanical efficiency as their air volume increases as the engine load increases, and when combined with a cooler, the average effective pressure can be significantly increased, making them the mainstream of superchargers. It's summery.

Conventionally, the exhaust turbine supercharger, which plays such an important role, is equipped with a rotation speed sensor that detects the turbine rotation speed. The detection signal from the rotation speed sensor is then input to a tachometer or recorder and displayed and recorded as a measured value, and the driver uses the above measured value and engine load etc. to supercharge the engine during patrol monitoring or periodic inspection. Determining whether there is an abnormality in the machine's operation.

<Problem to be solved by the invention> However, in the conventional supercharger abnormality diagnosis method described above, a skilled operator can perform a diagnosis based on the rotational speed indicated by the tachometer needle, the data on the record paper, and the engine load condition. We make decisions based on our many years of experience and know-how.
For example, abnormalities such as bearing wear or poor lubrication are determined by taking into account not only the rotation speed but also the vibrations, noise, and temperature generated by the supercharger. Therefore, in conventional diesel engines, it is necessary to have a skilled operator frequently check the supercharger for abnormalities, which has the disadvantage that it is not possible to save labor and manpower for engine operation. Furthermore, as the judgment is based on visual inspection or experience, misidentification is inevitable, and it is almost impossible to accurately judge whether or not the turbine speed is appropriate for the engine load by taking into account the history of rotation speed fluctuations. It is possible.
Misidentification or overlooking a slight abnormality can lead to deterioration in engine combustion and even serious engine failure or damage.

Therefore, the purpose of this invention is to provide a new abnormality determination means based on conventional experience and experimental data, which can identify abnormalities in turbomachinery such as superchargers based on the detection signal from the rotation speed sensor. It is an object of the present invention to provide a diagnostic device for a turbo machine that can output the determination result as abnormality information and contribute to labor saving and efficiency in operation and maintenance of the turbo machine.

<Means for Solving the Problems> In order to achieve the above object, the turbomachine diagnostic device of the present invention includes a rotation speed sensor that detects the rotation speed of a turbine driven by combustion gas, and a detection device for this rotation speed sensor. Based on the signal, a first deceleration time from when combustion gas supply is stopped until the turbine reaches the first reference rotation speed, and a second deceleration time from when the turbine reaches the second reference rotation speed until it reaches the third reference rotation speed. a clock means for measuring time; and a first determining means for determining whether the first deceleration time is greater than or equal to a predetermined allowable lower limit value and less than a predetermined allowable upper limit value based on a clock signal from the time measure means. and a second determining means for determining whether or not the second deceleration time is equal to or greater than a predetermined allowable lower limit value, the rotating part of the turbine or the The present invention is characterized in that abnormalities in the bearing portion and the combustion gas supply system can be diagnosed when the combustion gas supply is stopped.

<Operation> When the supply of combustion gas to the turbomachine is stopped and a stop operation begins, the rotational speed of the decelerating turbine is detected by the rotational speed sensor and inputted as a detection signal to the clock means. The timing means is configured to determine, based on the detection signal, a first deceleration time from when combustion gas supply is stopped until the turbine reaches a first reference rotation speed, and a time from when the turbine reaches a second reference rotation speed to a third reference rotation speed. The second deceleration time until reaching the second deceleration time is measured. Next, the first determination means determines whether or not the first deceleration time measured by the timer means is greater than or equal to a predetermined lower limit value and less than or equal to a predetermined upper limit value. If it is determined that the first deceleration time is less than the allowable lower limit value, it is pointed out that the sliding resistance of the turbine rotating part is large, for example, while if it is determined that the first deceleration time is greater than the allowable upper limit value, it is pointed out that, for example, there is an abnormality in the combustion gas stop system. Furthermore, the second determining means determines whether or not the second deceleration time measured by the time measuring means is equal to or greater than the allowable lower limit value. Then, if it is determined that the second deceleration time is less than the allowable lower limit value, for example, poor lubrication or damage to the turbine bearing portion is pointed out.

<Examples> The present invention will be described in detail below with reference to illustrated examples.

FIG. 1 is a schematic diagram of a diesel engine equipped with the turbomachine diagnostic device of the present invention, where 1 is a diesel engine, and 2 is a diesel engine 1
A supercharger as a turbomachine that is driven by the exhaust gas of
A rotation speed sensor 4 detects the rotation speed of the engine, and 4 is provided with a timing means and first and second discrimination means, which will be described later. A computer 5 as a device is a display device that displays the determination results output from the computer 4 and information regarding abnormal parts.

FIG. 2 is a diagram showing changes over time in the supercharger rotational speed N when the diesel engine is stopped. Actual rotation speed N detected by the rotation speed sensor 3
(t), as shown by the solid line A in the figure, when the fuel supply to the engine is cut off at time t ₀ , the steady rotation speed n ₀
It gradually decreases from ts to 0 at time ts, and the supercharger 2 completely stops. The timing means of the computer 4 is configured to measure first, second, and third reference rotational speeds n ₁ , n 2 , which are shown on the vertical axis of FIG. 2 as characteristic rotational speeds of the supercharger ₂ on the standard deceleration curve. n ₃ is stored in advance, and the actual rotation speed of the supercharger indicated by the detection signal from the rotation speed sensor 3 reaches the above-mentioned reference rotation speeds n ₁ , n ₂ , n ₃ at times t ₁ , t ₂ , t ₃ is measured, and the first deceleration time (t ₁ −t ₀ ) and the second deceleration time (t ₃ −t ₂ ) are calculated from the above-mentioned time t ₀ and these times. Note that the period between the first and second reference rotational speeds n ₁ and n ₂ is a transition region where the standard deceleration curve shifts from a steep slope to a gentle slope, and is therefore excluded from the deceleration time calculation.

On the other hand, the first determining means of the computer 4 is
The first deceleration time (t ₁ - t ₀ ) calculated by the timing means
is obtained from the experimental results and is greater than or equal to a predetermined allowable lower limit value δ ₂ and less than a predetermined allowable upper limit value δ ₁ , and is determined to be within the allowable range (δ ₁ ≦ (t ₁ − t ₀ )
≦δ ₂ ), it is determined to be normal; otherwise, it is determined to be abnormal (see steps S2 and S3 in FIG. 3). and,
If the first deceleration time (t ₁ - _{t 0} ) is too long, it is assumed that the fuel is running out due to poor sliding of the fuel rack, etc., and a signal indicating "fuel stop system abnormality" is output to the display device 5, and the first deceleration is stopped. If the time (t ₁ − _{t 0} ) is too short,
Rotational defects due to contact between the turbine blades and casing, eccentricity of the rotating shaft, etc.
A signal indicating "eccentricity exists" is output (see steps S5 and S6 in FIG. 3). Further, the second determining means of the computer 4 determines that the second deceleration time (t ₃ −t ₂ ) calculated by the time measuring means is a predetermined allowable lower limit value δ ₃ .
Determine whether or not it is greater than or equal to ((t ₃ − _{t 2} )≧δ ₃ )
If so, it is determined to be normal, otherwise it is determined to be abnormal (see step S4 in FIG. 3). If the second deceleration time (t ₃ - _{t 2} ) is too short, the abnormality is in the gentle slope region of the deceleration curve, and a signal indicating "insufficient lubrication or damage to the bearing" is output to the display device 5 (the second deceleration time (t 3 −t 2 ) is too short. (See step S7 in Figure 3).

The diagnostic operation of the computer 4 having the above configuration will now be described with reference to the flowchart of FIG.

Now, when the fuel supply to the diesel engine 1 is cut off at time _t0 , the rotation speed sensor 3 that detects the rotation speed of the supercharger 2 detects the actual rotation speed N(t) as shown by curve A in FIG. The relevant time data is input into the computer 4 in step S1. Then, the time measuring means of the computer 4 sequentially measures the times when the curve A reaches the first, second, and third reference rotational speeds n ₁ , n ₂ , n ₃ , and calculates the first deceleration time (t ₁ −t ₀ ) and the second deceleration time (t ₃ −t ₂ ).

The first determining means of the computer 4 is a step
In S2, it is determined whether the first deceleration time (t ₁ - t ₀ ) is less than or equal to the allowable upper limit value δ ₁ , and if it is determined to be less than or equal to δ ₁ , it is assumed to be normal and the process proceeds to step _S3 ; If it is determined that the time is too long, the process proceeds to step S5, and the display device 5 displays "Fuel stop system abnormality". In step S3, it is further determined whether or not the first deceleration time (t ₁ -t ₀ ) is equal to or greater than the allowable lower limit value δ ₂ .If it is determined to be equal to or greater than δ ₂ , it is determined to be normal and the process proceeds to step _S4 ; If it is determined that the time is less than that, the time is too short, and the process proceeds to step S6, where the display device 5 displays "Rotating part sliding resistance, eccentricity". Next, in step S4, the second determining means of the computer 4 determines whether the second deceleration time (t ₃ −t ₂ ) is the allowable lower limit value δ ₃
If it is determined to be δ ₃ or more, the diagnosis is concluded as normal, but if it is determined to be less than δ ₃ , the time is too short, so the process proceeds to step S7, and the display device 5 displays “Bearing Lubrication”. "Defective or damaged" is displayed.

In this way, in the above embodiment, the rotation speed sensor 3 is provided on the rotation shaft of the supercharger 2, which is normally supported by a rolling bearing and has low rotational resistance, so that even the slightest abnormality is sensitively reflected. When the engine is stopped, when abnormalities are easy to detect, the computer 4 analyzes the detection signal from the rotation speed sensor, so it can detect faulty shutoff of the fuel supply system, faulty rotation of the turbocharger, and poor lubrication or damage to the bearings. It has the advantage of being able to be detected accurately and reliably. Furthermore, abnormalities such as faulty shutoff or faulty turbocharger rotation that appear early or suddenly after fuel supply cutoff may cause the first deceleration time (t ₁ - t ₀ ) at the first steep slope part of deceleration curve A to be too large or too small. Abnormalities such as poor lubrication that appear slowly are determined by determining whether the second deceleration time (t ₃ - _{t 2} ) in the gentle slope section after the transition area of deceleration curve A is too small, making it easy to detect abnormalities. becomes more certain. Moreover, since all the diagnostic results obtained by the computer 4 are displayed on the display device 5, the driver's effort in monitoring the engine can be reduced, and the possibility of overlooking abnormalities can be reduced.

Note that the first, second, and third reference rotation speeds n ₁ ,
It goes without saying that n ₂ , n ₃ and the allowable lower limit values δ ₁ , δ ₂ , δ ₃ can be arbitrarily set by the driver on the computer 4 based on data obtained through experiments regarding the engine.

In the above embodiment, a supercharger of a diesel engine was explained as an example of a turbomachine, but it goes without saying that the diagnostic device of the present invention can also be applied to a gas turbine or the like.

<Effects of the invention> As is clear from the above explanation, the turbomachine diagnostic device of the invention uses a rotation speed sensor to detect the rotation speed of the turbine driven by combustion gas, and the turbine is A first deceleration time until reaching a first reference rotational speed and a second deceleration time from reaching a second reference rotational speed until reaching a third reference rotational speed are measured by a timing means, and the first deceleration time is determined by a predetermined time. A first determining means determines whether the second deceleration time is greater than or equal to a tolerable lower limit value and less than or equal to a predetermined tolerable upper limit value, and a second determining means determines whether or not the second deceleration time is less than or equal to a predetermined tolerable lower limit value. Determine and select the first and second
Based on the determination results of the determination means, it is possible to diagnose abnormalities in the rotating parts, bearings, and combustion gas supply system of the turbine even when the engine is stopped. Slight abnormalities in rotational speed due to poor lubrication, damage, contact between rotating parts, or failure to shut off the combustion gas supply system can be detected accurately and reliably, making it possible to prevent serious failures or damage to turbomachinery due to these abnormalities. It greatly contributes to labor saving and efficiency in machine operation and maintenance.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a diesel engine equipped with a supercharger equipped with the diagnostic device of the present invention, Fig. 2 is a diagram showing the change in supercharger rotation speed over time when the diesel engine is stopped, and Fig. 3 is a diagram of the above-mentioned diesel engine. It is a flowchart showing the flow of processing of the diagnostic device. 1... Diesel engine, 2... Supercharger, 3
...Rotation speed sensor, 4...Computer, 5...
Display device.

Claims (1)

[Scope of Claim for Utility Model Registration] A diagnostic device for a turbo machine that rotationally drives a turbine using combustion gas, which comprises: a rotation speed sensor that detects the rotation speed of the turbine; A timer for measuring a first deceleration time from when gas supply is stopped until the turbine reaches a first reference rotation speed, and a second deceleration time from when the turbine reaches a second reference rotation speed until it reaches a third reference rotation speed. and, based on the clock signal from this clock means, the first
a first determining means for determining whether the deceleration time is greater than or equal to a predetermined lower limit value and less than or equal to a predetermined upper limit value; and a second determining means for determining whether the deceleration time is greater than or equal to a predetermined lower limit value. and a second determining means,
Diagnosis of a turbomachine characterized in that an abnormality in a rotating part, a bearing part, or a combustion gas supply system of a turbine can be diagnosed when the combustion gas supply is stopped, based on the determination results of the first and second determination means. Device.