RU2560972C2 - Method of in-place diagnostics of wear of bearings of internal combustion engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention relates to machine operation and can be used for diagnosing of internal combustion engines. The method of in-place diagnostics of wear of bearings of internal combustion engines consists in measurement of pressure in the oil main line during the engine operation, consists in that the oil pressure is measured in the oil main line in the channel section, located between the main and crank bearings on the cranked shaft axis during no-load operation of the engine, and from the value of the measured pressure the allowable wear of the crank bearing is obvious. The operability of bearings generally is pre-determined by conditions of greasing and in turn wear of bearings result in pressure decrease in various system parts.

EFFECT: possibility of prevention of failures of bearings by advance identification of pre-failure state and timely maintenance of ICE, for example, with replacement of cranked shaft inserts and recovery of technical condition of bearings ensuring the hydrodynamic effect of liquid friction.

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Description

The invention relates to the field of operation of machines and can be used in the diagnosis of internal combustion engines (ICE).

The method of in-place diagnosis of the degree of wear of bearings of internal combustion engines consists in measuring the pressure in the oil line during engine operation, characterized in that the oil pressure is measured in the oil line in the channel section located between the main and connecting rod bearings along the crankshaft axis when the engine is running without load, and by the value of the measured pressure judge the permissible degree of wear of the connecting rod bearing.

The performance of the bearings is mainly determined by the lubrication conditions, and in turn, wear of the bearings leads to a decrease in pressure in various parts of the lubrication system [1].

State of the art

The level of technological development in the methods for diagnosing the degree of wear of ICE bearings is determined by the known methods for diagnosing the degree of wear based on measuring the oil pressure in various parts of the ICE lubrication system.

In analogue, a method for diagnosing the degree of wear of ICE bearings, ed. St. No. 1134897 (class G01M 15/00) during in-place diagnostics [2], the pressure in the main oil line is measured. This method involves connecting a hydraulic accumulator with a throttle device to the engine at the time of the experiment and determining the intensity of the pressure drop in it using two pressure gauges in certain modes. The disadvantage of this method is the need to install complex in design hydraulic accumulator devices.

In the prototype according to ed. St. No. 20066811 (class G01M 15/00) [3] use the pressure measurement at two points of the lubrication system for in-place diagnostics of the degree of wear of bearings of an internal combustion engine.

The method consists in measuring the pressure in the central oil circuit of the internal combustion engine and comparing the obtained pressure values with the reference values determined for the new engine. Compared to determine the degree of wear of the bearings.

In this case, the pressure measurement is carried out at least at two points of the engine lubrication system, the first of which is located at the outlet of the discharge section of the pump, these pressures are converted and compared with reference values. As a second pressure measuring point, a point is taken at the inlet to the diagnosed portion of the engine.

For a reference engine, determine the relationship between the ratio of the magnitude of the first pressure to the magnitude of the second on the degree of wear of the bearings or the ratio of the difference in the magnitude of the first and second pressures to the magnitude of the second on the degree of wear. On an idle engine with clean filters, the ratio of the difference between the values of the first and second pressures to the value of the second pressure is determined and the values of these relations are compared with a reference dependence on the degree of bearing wear. Moreover, the growth of this ratio corresponds to an increase in the degree of wear.

The disadvantage of this method is the dependence of the diagnostic results on many factors of the state of the elements of the engine lubrication system, the method requires extensive experience of the diagnostic operator.

An analysis of the known methods shows the feasibility of finding a method for assessing the technical condition of ICE bearings while preserving the advantages of previously existing methods and providing the possibility of determining deeper relationships of the structural parameter with the diagnostic for in-place diagnosis of the degree of wear of the ICE bearing.

The aim of the invention is to determine the degree of wear of the internal combustion engine bearings and to identify the limit state of the engine. This goal is achieved by the fact that in the proposed method of in-place diagnosis of the degree of wear of ICE bearings, the pressure in the oil line is measured in the area of the oil supply channel to the connecting rod bearings along the crankshaft axis after the main and to the connecting rod bearings of the crankshaft when the engine is without load, which is in any mode during operation must be greater than zero. The magnitude of the excess of the measured pressure above zero is judged on the degree of wear of the bearings of the internal combustion engine, and when the measured pressure reaches zero during operation, it is judged the onset of the limit state.

Disclosure of invention

The lubrication system of an internal combustion engine provides lubrication, cooling, and cleaning of parts and components. The main purpose of the internal combustion engine lubrication system is to provide the bearings with a hydrodynamic lubrication effect (liquid friction), which is achieved in operation by a certain ratio between the engine load, the actual value of the diametrical clearance of the bearing, which changes due to wear, the supply pressure of the lubricated material, its viscosity and the crankshaft speed .

It is also known that wear of individual joints and wear of bearings during operation leads to a general decrease in the pressure level in the lubrication system, which is shown by pressure gauge 1 (Fig. 1) and a gradual deterioration in the lubrication conditions of bearings, which must be pre-diagnosed and prevent changes in the fluid friction in bearings in semi-dry or dry friction, which can lead to intensive wear of the bearing and their failure.

The proposed method will allow to diagnose the degree of wear of the bearings, prevent failures, as it allows you to determine the degree of liquid friction of the bearing even at the minimum crankshaft speed when the engine is running without load.

Most often, connecting rod bearings fail, because a general decrease in pressure in the lubrication system negatively affects the decrease in oil supply to the connecting rod bearings.

In FIG. 1 presents a functional diagram of the engine lubrication system containing the following elements:

1 - pressure gauge;

2 - the main oil line;

3 - oil fine filter;

4 - oil cooler;

5 - safety valve;

6 - oil intake;

7 - pressure reducing valve;

8 - oil pump;

9 - coarse filter;

10 - filter bypass valve.

In the presented diagram (Fig. 1) it is seen that the most distant connecting rod bearings are not lubricated directly from the oil pump. Oil passes to them through main bearings and channels of the rotating crankshaft.

In fact, the lubrication conditions of the connecting rod bearings (Fig. 2) and their reliability are determined by the presence and magnitude of the pressure inside the channels along the crankshaft axis. In the cavity of the connecting rod neck (15) and the inlet channel (14) there will be oil under pressure, if it is at the intersection of the channels (13) at the entrance to the inlet channel to the connecting rod cavity. In turn, the oil will reach the point (13) if there is sufficient pressure in the annular channel (11) of the main bearing, which is fed with oil from the channel (12) in the main neck.

The structural parameter associated with the wear of ICE bearings and at the same time determining the operability of the most loaded and often failing connecting rod bearings is the oil pressure at the inlet of the connecting rod cavity at point (13).

The diagnostics of the general wear of ICE bearings, thus, boils down to the fact that it is necessary to determine the presence of pressure at the inflection point of the channels along the axis of the crankshaft in any way possible.

The implementation of the invention

In FIG. Figure 3 shows an example implementation of the invention by creating a control output by connecting a transitional rotating sleeve (16) to the crankshaft channel (14) along the axis of the crankshaft at point (13). When conducting diagnostics, any low-pressure meter, for example, a pressure gauge, is installed at the output of the coupling in the non-rotating part.

After diagnosis, the output is suppressed by screwing in a threaded sealed plug. The presence and magnitude of the pressure determines the integral degree of wear of the diagnosed ICE bearings, and in the absence of oil and pressure, the onset of the limit state is judged.

When developing this method, at the KAMAZ engine plant in bench conditions, pressure measurements were taken along the axis of the crankshaft and diagnostic standards were determined. The possibility of implementing the method on a car, its reliability and informativeness is confirmed.

Technical result

The technical result consists in the possibility of preventing failure of the connecting rod bearings by identifying in advance a precautionary condition and timely maintenance of the internal combustion engine, for example, by replacing the crankshaft liners and restoring the technical condition of the bearings, which will ensure the hydrodynamic effect of liquid friction.

Using the proposed method for assessing the technical condition of the internal combustion engine also allows you to predict the time of trouble-free operation of the engine to the limit state.

Claims (1)

The method of in-place diagnostics of the degree of wear of bearings of an internal combustion engine, which consists in measuring the pressure in the oil line during engine operation, characterized in that the oil pressure is measured in the oil line in the channel section located between the main and connecting rod bearings along the crankshaft axis when the engine is running without load , and by the value of the measured pressure above zero, they judge the degree of wear of the bearings of the internal combustion engine, and when the value of the measured pressure is equal to n Liu judge the occurrence of the limit state.

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