Data processing: measuring – calibrating – or testing – Measurement system – Performance or efficiency evaluation
Reexamination Certificate
2000-05-15
2003-04-01
Hoff, Marc S. (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system
Performance or efficiency evaluation
C702S183000, C702S033000, C702S113000, C700S039000, C700S046000, C700S093000, C123S179150, C123S339150, C374S055000, C374S101000, C374S127000
Reexamination Certificate
active
06542853
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a life estimation device for an engine which collects data on operation parameters, such as engine rotational speed, which values change when an engine of a construction machine or other machine is operating, and estimates the life of the engine based on the data on the operation parameters. The present invention also relates to a life estimation device for an engine which collects data on the operation parameters, such as engine rotational speed, which values change when a machine having a heat source, such as an engine, is operating, and estimates the life of the engine of the machine based on the data on the operation parameters.
BACKGROUND ART
It is extremely important to accurately estimate the time of overhaul for inspections and maintenance services of construction machines.
Because if the time of overhaul is accurately estimated, serious accidents, such as major damage to the engine, can be prevented by executing maintenance at an appropriate time. Also, estimating the time of overhaul accurately makes maintenance planning possible. In other words, the advantages are that accurate production planning, including vehicle schedule planniing, is possible, preparing parts required for overhaul at the required time is possible, and management of mechanics is easier.
In construction machines, however, the operating conditions of the engine greatly differ depending on the operating environment and operation of the individual user, and the time required for overhaul greatly differs even if the same model and same type engine is used. A simple determination of the overhaul time of an engine is not possible.
Therefore, it is required to accurately estimate the time of overhaul, that is, the life of the engine for an individual construction machine and individual engine.
The life of an engine is determined by the actual damage quantity exerted on the engine; that is, the accumulated load applied to the engine.
However, a numeric representation of the damage quantity exerted on the engine is actually difficult, so an indirect numeric representation of the damage quantity exerted on the engine based on the operating status of the engine at respective occasions has been attempted.
In other words, conventionally, the operating status of the engine is periodically recorded by a service tool, and the time of overhaul is determined by comparing the recorded value with the preset threshold value. For example, the valve clearance is actually measured, and this measured value is compared with the threshold value as instructed in the shop manual, and the time of overhaul is judged when the measured value exceeds the threshold value. The sound of the engine is also listened to, and the time of overhaul is judged by whether an abnormal sound is heard.
However, such operating states of the engine at each occasion do not accurately indicate the damage quantity exerted on the engine, and judgment on whether it is the time of overhaul greatly depends on the skill and experience of the mechanic. Therefore, the estimation of the time of overhaul is not always accurate.
Another attempt is to collect not only the operating states of the engine on respective occasions, but also to collect data on the engine (e.g. horse power of the engine) over a long period of time, determining the time of overhaul from the time-based changes.
However, it is difficult to represent the damage quantity actually exerted on the engine by numerics to determine the life of the engine. In other words, if the engine is continuously operated with a predetermined load (e.g. engine is always operated at a rated point), the damage quantity can be estimated relatively easily, assuming that the damage quantity increases in proportion to time, but if the load of the engine fluctuates as time elapses, numeric representation of the damage quantity is difficult. As a result, the time of overhaul has been determined based on the skill and experience of the mechanic.
In this way, a conventional method for estimating the time of overhaul, where judgment is not based on numeric representation of damage actually exerted on the damage, but depends on the skill of the mechanic, was not very accurate.
Because of this, it was always possible that an appropriate overhaul could not be taken at the necessary time, and a serious accident, such as major damage to the engine, occurred.
With the foregoing in view, it is the first object of the present invention to accurately represent the damage quantity exerted on the engine by numerics, so that the life of the engine can be automatically and accurately estimated without expert skills.
The life of the engine is determined not only by the above mentioned accumulation of load but also by the time the engine is exposed to heat.
In this case, there are two types of damage exerted on the engine, one is the drop in strength which occurs when the engine is exposed to high temperature. This is called “heat temperature fatigue”. The other damage is heat deterioration which is caused by repeated rise and fall of the temperature. This is called “thermal fatigue”.
Numeric representation of such damage quantity exerted on the engine due to heat was as difficult as the above mentioned numeric representation of damage quantity exerted on the engine due to the accumulation of load.
With the foregoing in view, it is the second object of the present invention to accurately represent the damage quantity exerted on a machine having such a heat source as an engine (e.g. power train which is influenced by the heat of the engine itself, or heat generated by the engine) by numerics, so that the life of the machine having a heat source can be automatically and accurately estimated without expert skills.
DISCLOSURE OF THE INVENTION
The first aspect to the sixteenth aspect of the present invention are to achieve the first object.
The first aspect of the present invention is a life estimation device for an engine which collects data of operation parameters which values change when the engine is operating and estimates a life of the engine based on the data of the operation parameters, comprising:
load map setting means (
4
) for selecting one operation parameter or two or more operation parameters indicative of a load exerted on the engine, and dividing a value of the one operation parameter or combinations of values of the two or more operation parameters into a plurality of levels, so as to set a one-dimensional or two- or more dimensional load map for indicating a distribution of magnitude of the load exerted on the engine;
operation parameter detection means (
2
,
3
) for detecting the values of the operation parameters;
time integration means (
7
,
8
), by detecting the operation parameters by the operation parameter detection means until a predetermined time elapses, for integrating a time during which operation parameter values belonging to the respective level are detected for each level of the load map;
weight setting means (
5
) for setting a weight in accordance with the load of the respective level for each level of the load map;
damage quantity calculation means (
9
) for determining the weighted integration time for each level of the load map by weighting the integration time integrated by the time integration means in accordance with the weight set by the weight setting means, and calculating an actual damage quantity exerted on the engine until the predetermined time elapses based on the integration time weighted for each level of the load map;
correspondence relationship setting means (
6
) for presetting a correspondence relations hip between a magnitude of the damage quantity and a length of life by pre-operating the engine; and
life estimation means (
10
) for determining a life corresponding to the actual damage quantity calculated by the damage quantity calculation means from the correspondence relationship preset by the correspondence relationship setting means, and outputting the determined life as the estimated life of the engine.
According to the conf
Hashimoto Haruo
Ichikawa Ichio
Iijima Koji
Murakami Taku
Ohkawa Hiroshi
Desta Elias
Hoff Marc S.
Komatsu Ltd.
Varndell & Varndell PLLC
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