GB/T 7184-2023 Reciprocating internal combustion engines - Evaluation method of vibration
Introduction
This document establishes an evaluation method for the vibration of reciprocating internal combustion engines (hereinafter referred to as "engines"). This document addresses the evaluation of vibration on the main structure of the engine, mainly to avoid problems with the auxiliary equipment installed on it.
Reciprocating machinery is typically characterized by swinging mass, periodically changing output (input) torque and pulse force in the auxiliary pipeline, all of which will produce great alternating force on the main support and increase the vibration amplitude of the main support frame. The amplitude is generally higher than that of rotating machinery, but because it mainly depends on the structural characteristics of the machinery, reciprocating machinery is more stable than rotating machinery in the service life.
For reciprocating internal combustion engines, measuring the vibration of the main structure of the engine according to this document can only provide a general concept of the stress and vibration state of the engine components themselves. For example, the torsional vibration of rotating components cannot be evaluated by measuring the mechanical structural parts. Where the guidance value is exceeded which is established based on the empirical data of similar engines, it mainly damages the parts (such as booster, heat exchanger, speed controller, filter and pump) installed on the engine, the connecting pieces (such as pipeline) between the engine and its external parts or the monitoring instruments (such as pressure gauge and thermometer). However, it mainly depends on the design of these parts themselves and their fasteners to predict to what extent the vibration reaches will cause damage.
In some cases, it is necessary to carry out special measurements on some parts and positions of the engine to determine that their vibration values are within the allowable range. Although vibration measurements are sometimes within the allowable range, problems may still occur because of the different parts of various engines.
These problems can be corrected by specific "local measurements" (such as avoiding resonance). Nevertheless, experience has shown that in most cases it is feasible to use measurable variables to characterize vibration conditions and give guidance values. This shows that measurable variables and variables values may give reliable evaluation in most cases. In order to quantitatively describe the vibration of reciprocating internal combustion engines in a simple manner, the term "vibration intensity" will be adopted in this document.
The vibration value of an engine is affected not only by the characteristics of the engine body itself, but also by the foundation to a great extent. Because the reciprocating internal combustion engine can be regarded as the vibration source, vibration isolation is necessary between the engine and the foundation. The vibration response of the foundation will have a considerable impact on the vibration of the engine. These vibration conditions also depend on the transmission characteristics of the surrounding environment of the engine, so the environmental impact of the engine cannot be completely determined by the vibration of the engine itself. Therefore, this document is only intended as a reference for the environmental impact of the engine.
1 Scope
This document describes an evaluation method for vibration of non-rotating components and non-reciprocating components of reciprocating internal combustion engines.
This document is applicable to reciprocating internal combustion engines defined in GB/T 21404 (hereinafter referred to as "engines" unless otherwise specified) and other internal combustion engines for which no suitable standard is available.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 2298 Mechanical vibration, shock and condition monitoring - Vocabulary
GB/T 6072.1 Reciprocating internal combustion engines - Performance - Part 1: Declarations of power, fuel and lubricating oil consumptions and test methods - Additional requirements for engines for general use
GB/T 6072.3 Reciprocating internal combustion engines - Performance - Part 3: Test measurements
GB/T 13824 Mechanical vibration of rotating and reciprocating machinery - Requirements for instruments for measuring vibration severity
GB/T 14412 Mechanical vibration and shock - Mechanical mounting of accelerometers
GB/T 14777 Geometrical orientation and directions of movements
GB/T 21404 Internal combustion engines - Determination and method for the measurement of engine power - General requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 2298, GB/T 6072.1 and GB/T 14777 and the following apply.
3.1
vibration severity
a value, or set of values, such as a maximum value, average or r.m.s. value, or other parameter that is descriptive of the vibration. It may refer to multiple instantaneous values or average values
Note: Vibration severity is a generic term, which was used frequently in the part when involved with vibration speed, and is now also used for displacement and acceleration.
[Source: GB/T 2298-2010, 3.51, modified]
4 Measurement method
4.1 Measuring instruments
4.1.1 General
The measurement system, including sensors and cables, shall meet the requirements of GB/T 13824.
If the measurement system cannot fully meet the requirements of GB/T 13824, but the measurement results can meet the requirements of GB/T 13824, the measurement system can then be considered as an equivalent measurement system that meets the requirements of GB/T 13824.
Foreword I
Introduction II
1 Scope
2 Normative references
3 Terms and definitions
4 Measurement method
4.1 Measuring instruments
4.2 Operating conditions
4.3 Measurement of vibration severity
4.4 Records
4.5 Determination of vibration severity grades
5 Evaluation of vibration
Annex A (Normative) Evaluation of vibration for reciprocating internal combustion engines
Annex B (Informative) Vibration categories of reciprocating internal combustion engines
Bibliography
