Measuring and testing – Vehicle chassis – Steering
Reexamination Certificate
2000-04-20
2002-08-20
Fuller, Benjamin R. (Department: 2855)
Measuring and testing
Vehicle chassis
Steering
C701S213000, C340S992000, C340S438000
Reexamination Certificate
active
06435018
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vehicle abnormality diagnosis system for performing abnormality diagnoses, such as diagnosing malfunctions and predicting the service life of vehicles such as construction machines.
2. Description of the Related Art
In order to improve the reliability of a construction machine, carrying out abnormality diagnoses, such as diagnosing engine malfunctions, determining the extent of engine deterioration and predicting engine service life (predicting overhaul times), is essential. On the occasion when an abnormality diagnosis is performed, it is necessary to acquire, under the same operating conditions (condition that the machine is operated at a rated point on the torque curve), operating parameters the values of which change during construction machine operation, such as engine blow-by pressure, number of rotations, and fuel injection quantity. This is because it is not possible to compare data, and diagnose an abnormality unless operating parameters can be acquired under the same operating conditions.
Conventionally, operating parameters have been acquired in the following manner.
(a) First, the construction machine is shut down during work, and work is suspended.
(b) Then, as many measuring instruments, such as a pressure gauge and tachometer, as the number of operating parameters to be measured are mounted to an engine.
(c) In a state where a load is applied to the stopped construction machine and the torque converter is made to stall, engine speed and fuel injection quantity are carried to the rated point.
(d) If the value of an operating parameter achieves saturation and is stable, the data measured by the measuring instrument are read out and recorded.
However, shutting down the construction machine, and suspending work for the sake of taking measurements as mentioned in (a) above brings about reduced work efficiency.
Further, a person (serviceman) skilled in measurement work is needed to perform the work of mounting the measuring instruments for taking measurements, controlling the construction machine so that a fixed operating condition is achieved, and recording measurement data as mentioned in (b), (c), and (d) above,. Consequently, personnel costs will be increased for measurement purposes.
Further, as indicated in (c), (d) above, because measurements of operating parameters are taken in a state in which the construction machine has been shut down, and a torque converter has been made to stall, heat is generated by the torque converter. For this reason, a fixed operating state cannot be maintained for a long period of time (the limit is 20 seconds at the most). As a consequence, problems such as the following are incurred.
FIG. 6
shows conventional operating parameter measurement results. The horizontal axis is the time axis, and the vertical axis indicates the size of the respective operating parameters.
FIG. 6
shows a case in which the respective parameters of engine speed, governor rack position (voltage value), pressure, exhaust temperature, oil temperature, and blow-by pressure are obtained. When engine speed and governor rack position (voltage value) rise, and a stable state (rated point) is achieved, the blow-by pressure also stabilizes, as indicated by S, and measurements can be taken at a time ts during the period S when blow-by pressure is stable. Furthermore, in the figure, blow-by pressure is pulsating, but measurements are taken after creating a stable waveform by performing signal processing, such as causing the signal to pass through a low pass filter. Governor rack position refers to a voltage value, which indicates the control rack position of an electrical governor of a fuel injection pump.
As shown in the same
FIG. 6
, out of consideration for heat generation by the torque converter, the stable period S after engine speed and governor rack position (voltage value) have risen all the way is very brief. Consequently, exhaust temperature does not reach saturation, and accurate data cannot be collected in the time ts.
As described above, when using the conventional method, wherein measurements are taken in a state in which the construction machine is shut down, depending on the type of operating parameter, saturation cannot be achieved, and accurate data cannot be collected.
In recent years, there have been attempts to acquire an operating parameter of a construction machine in time series fashion, and to carry out an abnormality diagnosis on the basis of the acquired time series data. Consequently, in addition to periodically making engine operating conditions fixed operating conditions, it is necessary to periodically acquire operating parameters. For this reason, as indicated in (a) above, the construction machine must be periodically shut down, and work must be suspended, causing the drop in work efficiency to become even more serious.
OBJECTS AND SUMMARY OF THE INVENTION
With the foregoing in view, a first object of the present invention is to enable the measurement of an operating parameter under a fixed operating condition without bringing about rising personnel costs, and without causing construction machine work efficiency to drop, and to enable the reliable acquisition of accurate data.
Further, conventionally, engine blow-by pressure has been detected, and an engine abnormality diagnosis has been made based on the size of the detected blow-by pressure. Blow-by pressure is a useful operating parameter for quantitatively detecting damage done to an engine.
Therefore, a second object of the present invention is to diagnose an engine abnormality more accurately by quantitatively detecting damage done to an engine using a new operating parameter related to blow-by pressure.
To achieve the first object of the present invention, a first invention is a vehicle abnormality diagnosis system for acquiring an operating parameter under a specified operating condition of a vehicle, a value of the operating parameter changing during an operation of the vehicle, and for diagnosing a vehicle abnormality on the basis of the value of the acquired operating parameter, wherein either a specified point or a specified area, at which the vehicle operating condition becomes the specified operating condition, is set beforehand from among points or areas on a travel route along which the vehicle travels, and an operating parameter of a point in time, at which the vehicle passed either the specified point or the specified area, is acquired, and an abnormality of a vehicle is diagnosed on the basis of a value of the acquired operating parameter.
According to the first invention, as shown in
FIG. 5
, either a specified point Q or a specified area Ar, at which an operating condition of a vehicle
50
becomes a specified operating condition, is set beforehand from among either each point or each area on a travel route
51
, which a vehicle
50
travels.
As shown in
FIG. 11
, an operating parameter P of a point in time ts
1
, ts
2
, ts
3
, ts
4
. . . , tsn, at which a vehicle
50
passes either a specified point Q or a specified area Ar, is obtained.
Then, as shown in
FIG. 12
, a vehicle abnormality is diagnosed on the basis of the values of these obtained operating parameters P (maximum values Pmax).
According to the first invention, since an operating parameter P is obtained under a specified operating condition while a vehicle
50
is travelling, there is no need to stop the vehicle for taking measurements. Consequently, work is not suspended, and a drop in work efficiency is not incurred. Further, since there is no need to perform the work of mounting measuring instruments, controlling a vehicle so that a fixed operating condition is achieved, or recording measured data, a person (serviceman), who is skilled at measurement work, is not required. Consequently, personnel costs do not rise.
Further, because an operating parameter can be obtained during vehicle
50
travel at a point, at which it becomes a specified operating condition, it is possible to collect accurate data in a
Hashimoto Haruo
Ichikawa Ichio
Murakami Taku
Satou Fumihide
Fuller Benjamin R.
Komatsu Ltd.
Stevens Maurice
Varndell & Varndell PLLC
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