CN114323661A - Combustion noise test analysis method and system in engine cylinder - Google Patents
Combustion noise test analysis method and system in engine cylinder Download PDFInfo
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Abstract
The invention provides a method and a system for testing and analyzing combustion noise in an engine cylinder, which are applied to an engine and comprise the following steps: installing a combustible mixed gas injection pipe at an original oil nozzle of the engine; arranging a pressure sensor and a vibration sensor on the engine, and arranging microphones around and under the engine; igniting combustible mixed gas injected into the cylinder by a spark plug at preset time intervals, and respectively collecting pressure intensity in the cylinder, vibration frequency of the cylinder and audio frequency generated by an engine; and calculating an acoustic response transfer function under the unit combustion pressure of the cylinder according to the pressure and the audio, and calculating a vibration response transfer function under the combustion excitation of the engine according to the vibration frequency. The combustion noise and the mechanical noise of the engine can be successfully separated through the method, the acoustic response transfer function and the vibration response transfer function are obtained, and the actual combustion noise and the actual vibration frequency of the engine which actually works are finally calculated.
Description
Technical Field
The invention relates to the technical field of automobile engines, in particular to a method and a system for testing and analyzing combustion noise in an engine cylinder.
Background
NVH (noise, vibration, comfort) performance is an important attribute requirement as engine products are developed, designed and tested. The NVH problem in the process of engine development and use is mainly represented by the vibration noise problem, and can be divided into three categories: combustion noise, mechanical noise, air noise. At present, mechanical noise and air noise are tested and controlled by a mature method and means, and combustion noise is only caused by high temperature and high pressure, the combustion speed is high, the space in a cylinder is closed, and the combustion noise of an engine is bound with the mechanical noise and cannot be separated and identified. In an automobile engine, combustion noise occupies a large proportion of total noise, and the research on how to reduce and optimize the combustion noise is of particular significance, and the test, identification and analysis of the combustion noise becomes a key field in the development process. In the engine development and test process, a combustion analyzer is used for roughly analyzing the combustion condition in an internal combustion engine cylinder, but the accuracy is poor, a combustion noise transfer function cannot be obtained, and the structural optimization direction cannot be provided. The combustion noise problem in the cylinder is indirectly evaluated by monitoring the rise rate of the pressure in the cylinder, and the method also cannot directly feed back the combustion noise level and cannot provide a structural optimization direction.
Therefore, in view of the shortcomings of the prior art, it is desirable to provide a method for accurately performing a test analysis of combustion noise in an engine cylinder.
Disclosure of Invention
Based on the above, the invention aims to provide a method and a system for testing and analyzing combustion noise in an engine cylinder, so as to accurately test and analyze the combustion noise in the engine cylinder.
The first aspect of the embodiment of the invention provides a method for testing and analyzing combustion noise in an engine cylinder, which is characterized by being applied to an engine, and the method comprises the following steps:
installing a combustible mixed gas injection pipe at an original oil nozzle of the engine, wherein the combustible mixed gas injection pipe is used for injecting combustible mixed gas into a cylinder of the engine, and the combustible mixed gas comprises propane and oxygen;
arranging a pressure sensor and a vibration sensor on the engine, and arranging microphones around and below the engine;
igniting combustible mixed gas injected into the cylinder through a spark plug at preset intervals, and respectively collecting pressure intensity in the cylinder, vibration frequency of the cylinder and audio frequency generated by the engine;
and calculating an acoustic response transfer function under the unit combustion pressure of the cylinder according to the pressure and the audio, and calculating a vibration response transfer function under the combustion excitation of the engine according to the vibration frequency, so as to calculate the actual combustion noise and the actual vibration frequency of the actually working engine respectively through the acoustic response transfer function and the vibration response transfer function.
The invention has the beneficial effects that: the combustible mixed gas injection pipe is installed at an original oil nozzle of the engine, the combustible mixed gas is injected into a cylinder of the current engine, further, a pressure sensor and a vibration sensor are arranged on the current engine, and microphones are arranged on the periphery and the lower side of the current engine. During testing, the combustible mixed gas injected into the cylinder is ignited by a spark plug at preset time intervals, the pressure in the cylinder, the vibration frequency of the cylinder and the audio frequency generated by the engine are respectively collected, finally, an acoustic response transfer function under the unit combustion pressure of the cylinder is calculated according to the pressure and the audio frequency, a vibration response transfer function under the engine combustion excitation is calculated according to the vibration frequency, and the actual combustion noise and the actual vibration frequency of the actually working engine are calculated according to the acoustic response transfer function and the vibration response transfer function respectively. The combustion noise and the mechanical noise of the engine can be successfully separated through the mode, the testing method provided by the application is carried out on the non-running engine, so that the mechanical noise does not exist, further, an acoustic response transfer function under pure combustion excitation and a vibration response transfer function of each component under combustion excitation can be obtained, and finally, the actual combustion noise and the actual vibration frequency of the engine which actually works can be calculated through the acoustic response transfer function and the vibration response transfer function.
Preferably, the step of arranging a pressure sensor and a vibration sensor on the engine includes:
taking out the preheating plug of the cylinder, and installing the pressure sensor at the original position of the preheating plug, wherein the pressure sensor extends into the cylinder;
the vibration sensor is arranged on the surfaces of the cylinder body, the cylinder head and the cylinder head cover of the cylinder, and the oil pan and the front end belt head cover of the engine.
Preferably, before the step of arranging microphones around and below the engine, the method further comprises:
placing a piston in the cylinder at top dead center to maximize a volume of a combustion chamber in the cylinder;
the engine is placed in the mid-air by an elastic rope and a hook.
Preferably, after the step of igniting the combustible mixture injected into the cylinder by the spark plug at preset intervals and respectively collecting the pressure in the cylinder, the vibration frequency of the cylinder and the audio frequency generated by the engine, the method further comprises:
and adjusting the pressure of the combustible mixed gas entering the cylinder through the combustible mixed gas injection pipe so as to control the combustion pressure and the combustion pressure increase rate in the cylinder.
Preferably, the formula for calculating the actual combustion noise of the engine actually working through the acoustic response transfer function is as follows:
the acoustic response transfer function x pressure of the cylinder in actual operation = actual combustion noise of the engine in actual operation;
the formula for calculating the actual vibration frequency of the actually working engine through the vibration response transfer function is as follows:
the vibration response transfer function x pressure of the cylinder actually operated = the actual vibration frequency of the engine actually operated.
The second aspect of the embodiment of the present invention provides an in-cylinder combustion noise test and analysis system for an engine, which is applied to the engine, and the system includes:
the fuel injection device comprises a first preparation module, a second preparation module and a fuel injection module, wherein the first preparation module is used for installing a combustible mixed gas injection pipe at an original fuel injection nozzle of the engine, the combustible mixed gas injection pipe is used for injecting combustible mixed gas into a cylinder of the engine, and the combustible mixed gas comprises propane and oxygen;
the second preparation module is used for arranging a pressure sensor and a vibration sensor on the engine and arranging microphones on the periphery and the lower part of the engine;
the acquisition module is used for igniting combustible mixed gas injected into the cylinder through a spark plug at preset intervals, and respectively acquiring pressure intensity in the cylinder, vibration frequency of the cylinder and audio frequency generated by the engine;
and the calculation module is used for calculating an acoustic response transfer function under the unit combustion pressure of the cylinder according to the pressure and the audio, calculating a vibration response transfer function under the combustion excitation of the engine according to the vibration frequency, and calculating the actual combustion noise and the actual vibration frequency of the actually working engine respectively through the acoustic response transfer function and the vibration response transfer function.
In the above system for testing and analyzing combustion noise in an engine cylinder, the second preparation module is specifically configured to:
taking out the preheating plug of the cylinder, and installing the pressure sensor at the original position of the preheating plug, wherein the pressure sensor extends into the cylinder;
the vibration sensor is arranged on the surfaces of the cylinder body, the cylinder head and the cylinder head cover of the cylinder, and the oil pan and the front end belt head cover of the engine.
In the above system for testing and analyzing combustion noise in an engine cylinder, the system for testing and analyzing combustion noise in an engine cylinder further includes a third preliminary module, and the third preliminary module is specifically configured to:
placing a piston in the cylinder at top dead center to maximize a volume of a combustion chamber in the cylinder;
the engine is placed in the mid-air by an elastic rope and a hook.
Among the above-mentioned engine in-cylinder combustion noise test analysis system, the engine in-cylinder combustion noise test analysis system still includes the adjustment module, the adjustment module is specifically used for:
and adjusting the pressure of the combustible mixed gas entering the cylinder through the combustible mixed gas injection pipe so as to control the combustion pressure and the combustion pressure rise rate in the cylinder.
In the above system for testing and analyzing combustion noise in an engine cylinder, the formula for calculating the actual combustion noise of the engine working actually through the acoustic response transfer function is as follows:
the acoustic response transfer function x pressure of the cylinder in actual operation = actual combustion noise of the engine in actual operation;
the formula for calculating the actual vibration frequency of the actually working engine through the vibration response transfer function is as follows:
the vibration response transfer function x pressure of the cylinder actually operated = the actual vibration frequency of the engine actually operated.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 is a flow chart of a method for in-cylinder combustion noise test analysis of an engine provided in a first embodiment of the present invention;
fig. 2 is a block diagram of an in-cylinder combustion noise test analysis system according to a third embodiment of the present invention.
The following detailed description will further illustrate the invention in conjunction with the above-described figures.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Several embodiments of the invention are presented in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
In the process of developing and testing an engine in the prior art, a combustion analyzer is used for roughly analyzing the combustion condition in a cylinder of the internal combustion engine in the conventional method, but the accuracy is poor, a combustion noise transfer function cannot be obtained, and the structural optimization direction cannot be provided. The combustion noise problem in the cylinder is indirectly evaluated by monitoring the rise rate of the pressure in the cylinder, and the method also cannot directly feed back the combustion noise level and cannot provide a structural optimization direction.
Referring to fig. 1, a method for testing and analyzing combustion noise in an engine cylinder according to a first embodiment of the present invention is shown, and the method for testing and analyzing combustion noise in an engine cylinder according to the present invention can successfully separate combustion noise and mechanical noise of an engine, and the method for testing and analyzing combustion noise in an engine cylinder according to the present invention is performed on a non-operating engine, so that mechanical noise does not exist, and further, an acoustic response transfer function under a pure combustion excitation and a vibration response transfer function of each component under a combustion excitation can be obtained, and finally, an actual combustion noise and an actual vibration frequency of an engine that actually operates can be calculated through the acoustic response transfer function and the vibration response transfer function.
Specifically, the method for testing and analyzing the combustion noise in the engine cylinder provided by the embodiment is applied to the engine, and comprises the following steps:
step S10, installing a combustible mixed gas injection pipe at an original oil nozzle of the engine, wherein the combustible mixed gas injection pipe is used for injecting combustible mixed gas into a cylinder of the engine, and the combustible mixed gas comprises propane and oxygen;
specifically, in this embodiment, it should be noted that the in-cylinder combustion noise test and analysis method of the engine provided in this embodiment is mainly used for testing and analyzing the magnitude of noise generated during actual operation of a cylinder in the engine.
Therefore, in this embodiment, it is necessary to prepare a completely assembled engine first, and at the same time, it is necessary to remove unnecessary pipes and wiring harnesses in the current engine, and remove the fuel injector and the starter of the current engine, while not filling the engine oil and the coolant.
Further, the cylinders of the current engine are numbered 1, 2, 3, 4 in sequence from front to back (in-line four-cylinder engines, the rest of the engine types and so on).
Furthermore, in this step, in order to facilitate the test, a combustible mixture injection pipe is installed at the original fuel injector of the current engine, and in use, the combustible mixture injection pipe is used for injecting a combustible mixture into the cylinder of the current engine, wherein the combustible mixture is a mixture of propane, oxygen and air.
Step S20, arranging a pressure sensor and a vibration sensor on the engine, and arranging microphones on the periphery and the lower part of the engine;
further, in this step, in order to measure the pressure and vibration frequency generated by the current engine during the combustion of the combustible mixture, a pressure sensor and a vibration sensor are continuously arranged in the engine, and microphones are arranged around and under the engine, and are used for collecting the audio generated by the current engine. The model of the vibration sensor is PCB356B 21.
Step S30, igniting the combustible mixed gas injected into the cylinder by a spark plug at preset time intervals, and respectively collecting the pressure in the cylinder, the vibration frequency of the cylinder and the audio frequency generated by the engine;
furthermore, in this step, the engine arranged as above is tested, and during the actual test, the combustible mixture injected into the cylinder of the current engine is ignited by the spark plug at preset intervals, and at the same time, the pressure in the current cylinder, the vibration frequency of the current cylinder and the audio frequency generated by the current engine are respectively and simultaneously acquired by the pressure sensor, the vibration sensor and the microphone arranged as above, and the acquired data of the pressure, the vibration frequency and the audio frequency are transmitted to the computer for corresponding processing.
And step S40, calculating an acoustic response transfer function under the unit combustion pressure of the cylinder according to the pressure and the audio frequency, and calculating a vibration response transfer function under the combustion excitation of the engine according to the vibration frequency, so as to calculate the actual combustion noise and the actual vibration frequency of the actually working engine respectively through the acoustic response transfer function and the vibration response transfer function.
Finally, in this step, it should be noted that, when the data such as the corresponding pressure, the vibration frequency, the audio frequency, and the like are respectively collected through the above steps, the computer starts an internal preset algorithm, calculates an acoustic response transfer function under the unit combustion pressure of the current cylinder according to the pressure and the audio frequency, and calculates a vibration response transfer function under the combustion excitation of the current engine according to the vibration frequency, so that the actual combustion noise and the actual vibration frequency of the actually working engine can be calculated through the acoustic response transfer function and the vibration response transfer function, respectively.
When the fuel injection device is used, the combustible mixed gas injection pipe is installed at the position of an original fuel injection nozzle of the engine, the combustible mixed gas is injected into a cylinder of the current engine, further, the pressure sensor and the vibration sensor are arranged on the current engine, and microphones are arranged on the periphery and the lower part of the current engine. During testing, the combustible mixed gas injected into the cylinder is ignited by a spark plug at preset time intervals, the pressure in the cylinder, the vibration frequency of the cylinder and the audio frequency generated by the engine are respectively collected, finally, an acoustic response transfer function under the unit combustion pressure of the cylinder is calculated according to the pressure and the audio frequency, a vibration response transfer function under the engine combustion excitation is calculated according to the vibration frequency, and the actual combustion noise and the actual vibration frequency of the actually working engine are calculated according to the acoustic response transfer function and the vibration response transfer function respectively. The combustion noise and the mechanical noise of the engine can be successfully separated through the mode, the testing method provided by the application is carried out on the non-running engine, so that the mechanical noise does not exist, further, an acoustic response transfer function under pure combustion excitation and a vibration response transfer function of each component under combustion excitation can be obtained, and finally, the actual combustion noise and the actual vibration frequency of the engine which actually works can be calculated through the acoustic response transfer function and the vibration response transfer function.
It should be noted that the above implementation procedure is only for illustrating the applicability of the present application, but this does not represent that the engine in-cylinder combustion noise test analysis method of the present application has only the above-mentioned implementation procedure, and on the contrary, the engine in-cylinder combustion noise test analysis method of the present application can be incorporated into a feasible embodiment of the present application as long as the method can be implemented.
In summary, the method for testing and analyzing combustion noise in an engine cylinder in the above embodiment of the present invention can successfully separate combustion noise and mechanical noise of an engine, and the testing method provided by the present application is performed on a non-operating engine, so that no mechanical noise exists, and further, the present application can obtain an acoustic response transfer function under a pure combustion excitation and a vibration response transfer function of each component under a combustion excitation, and finally, can calculate actual combustion noise and actual vibration frequency of an engine that actually works through the acoustic response transfer function and the vibration response transfer function.
The second embodiment of the invention also provides a method for testing and analyzing the combustion noise in the engine cylinder, which comprises the following steps:
similarly, in the present embodiment, it should be noted that the in-cylinder combustion noise test and analysis method of the engine provided in the present embodiment is also mainly used for testing and analyzing the magnitude of noise generated during actual operation of the cylinder in the engine.
Step S11, installing a combustible mixed gas injection pipe at the original oil nozzle of the engine;
in this embodiment, it should be noted that, it is also necessary to prepare an engine first, and install a combustible mixture injection pipe at the original fuel injector of the current engine, and in use, the combustible mixture injection pipe is used for injecting a combustible mixture, which is a mixture of propane, oxygen and air, into the cylinder of the current engine.
Step S21, taking out the preheating plug of the cylinder, and installing the pressure sensor at the original position of the preheating plug, wherein the pressure sensor extends into the cylinder; the vibration sensor is arranged on the surfaces of the cylinder body, the cylinder head and the cylinder head cover of the cylinder, and the oil pan and the front end belt head cover of the engine.
Further, in this step, in order to facilitate collecting the pressure and the vibration frequency generated by the current engine during the test, specifically, the step takes out the glow plugs of the four cylinders of the current engine, installs a pressure sensor at the original position of each glow plug, and the pressure sensor extends into the interior of the cylinder to accurately collect the pressure generated by each cylinder during the combustion of the combustible mixed gas.
In addition, in this step, it is possible to be at the block outer surface, the head outer surface, and the outer surface of the head cover of each cylinder. And the vibration sensors are arranged on the outer surface of the bottom of the oil pan of the current engine and the outer surface of the front end belt cover, so that the vibration frequency generated by the current engine is acquired in an all-around manner.
In this embodiment, it should be noted that, before the step of arranging microphones around and below the engine, the method further comprises:
step S31, placing the piston in the cylinder at the top dead center to enable the volume of the combustion chamber in the cylinder to be maximum; the engine is placed in the mid-air by an elastic rope and a hook.
Specifically, in this step, the piston of each cylinder is fixedly placed at the top dead center of each cylinder, i.e., at the highest point of each cylinder, so as to maximize the volume of the combustion chamber in each cylinder. Meanwhile, the current engine is suspended in the air through the elastic rope and the hook, so that the interference of the vibration of the ground on the test result of the current engine is avoided.
Step S41, arranging microphones around and below the engine;
further, in this step, microphones are disposed around and below the current engine. Specifically, in the step, a microphone is arranged at the positions one meter away from the front, above, left and right of the current engine, in addition, a microphone is arranged below the current engine, the microphone positioned below is directly placed on the ground and is right under the center of the oil pan of the current engine, and meanwhile, the center of the oil pan is 230mm away from the ground at the minimum.
Step S51, igniting the combustible mixed gas injected into the cylinder by a spark plug at preset time intervals, and respectively collecting the pressure in the cylinder, the vibration frequency of the cylinder and the audio frequency generated by the engine;
further, the current engine is tested in the step, specifically, the combustible mixed gas injected into each cylinder is ignited by the spark plug at preset time intervals, when the waste gas in the cylinder is discharged, new combustible mixed gas is injected again and ignited, and the above process is repeated for 3 seconds until the test is finished.
In the process of combustion of the combustible mixed gas in the cylinder, the pressure intensity in the current cylinder, the vibration frequency generated by the current cylinder and the audio frequency generated by the current engine are respectively collected through the arranged pressure sensor, the vibration sensor and the microphone.
In this embodiment, it should be noted that, after the step of igniting the combustible mixture gas injected into the cylinder by the spark plug at preset intervals, and respectively collecting the pressure in the cylinder, the vibration frequency of the cylinder, and the audio frequency generated by the engine, the method further includes:
and step S61, adjusting the pressure of the combustible mixed gas entering the cylinder through the combustible mixed gas injection pipe so as to control the combustion pressure and the combustion pressure increase rate in the cylinder.
Further, it should be noted that, in the process of combusting the combustible mixed gas in the cylinder, the step may adjust the pressure of the combustible mixed gas entering the cylinder through the combustible mixed gas injection pipe for multiple times, so as to control the combustion pressure and the combustion pressure increase rate in the cylinder.
And step S71, calculating an acoustic response transfer function under the unit combustion pressure of the cylinder according to the pressure and the audio frequency, and calculating a vibration response transfer function under the combustion excitation of the engine according to the vibration frequency, so as to calculate the actual combustion noise and the actual vibration frequency of the actually working engine respectively through the acoustic response transfer function and the vibration response transfer function.
Finally, in this step, it should be noted that, when the data such as the corresponding pressure, the vibration frequency, the audio frequency, and the like are respectively collected through the above steps, the computer starts an internal preset algorithm, calculates an acoustic response transfer function under the unit combustion pressure of the current cylinder according to the pressure and the audio frequency, and calculates a vibration response transfer function under the combustion excitation of the current engine according to the vibration frequency, so that the actual combustion noise and the actual vibration frequency of the actually working engine can be calculated through the acoustic response transfer function and the vibration response transfer function, respectively.
In addition, the present embodiment can know that the resonance band exists in the oil pan in the interval of 300Hz-600Hz and the response is strongest when 3 cylinders fire through the calculated vibration response transfer function.
In this embodiment, it should be noted that the formula for calculating the actual combustion noise of the engine actually working through the acoustic response transfer function is as follows:
the acoustic response transfer function x pressure of the cylinder in actual operation = actual combustion noise of the engine in actual operation;
the formula for calculating the actual vibration frequency of the actually working engine through the vibration response transfer function is as follows:
the vibration response transfer function x pressure of the cylinder actually operated = the actual vibration frequency of the engine actually operated.
The actual combustion noise and the actual vibration frequency generated by other engines in the actual operation process can be simply and rapidly solved through the formula, and the structural optimization direction of the engine can be effectively provided.
It should be noted that, the method provided by the second embodiment of the present invention, which implements the same principle and produces some technical effects as the first embodiment, can refer to the corresponding contents in the first embodiment for the sake of brief description, where this embodiment is not mentioned.
In summary, the method for testing and analyzing combustion noise in an engine cylinder in the above embodiment of the present invention can successfully separate combustion noise and mechanical noise of an engine, and the testing method provided by the present application is performed on a non-operating engine, so that no mechanical noise exists, and further, the present application can obtain an acoustic response transfer function under a pure combustion excitation and a vibration response transfer function of each component under a combustion excitation, and finally, can calculate actual combustion noise and actual vibration frequency of an engine that actually works through the acoustic response transfer function and the vibration response transfer function.
Referring to fig. 2, there is shown an in-cylinder combustion noise test and analysis system for an engine according to a third embodiment of the present invention, applied to an engine, the system including:
the first preparation module 12 is used for installing a combustible mixed gas injection pipe at an original oil nozzle of the engine, wherein the combustible mixed gas injection pipe is used for injecting combustible mixed gas into a cylinder of the engine, and the combustible mixed gas comprises propane and oxygen;
a second preparation module 22 for arranging a pressure sensor and a vibration sensor on the engine and arranging microphones around and under the engine;
the acquisition module 32 is used for igniting the combustible mixed gas injected into the cylinder through a spark plug at preset intervals, and respectively acquiring the pressure in the cylinder, the vibration frequency of the cylinder and the audio frequency generated by the engine;
and the calculation module 42 is configured to calculate an acoustic response transfer function under the combustion pressure per cylinder unit according to the pressure and the audio frequency, and calculate a vibration response transfer function under the combustion excitation of the engine according to the vibration frequency, so as to calculate an actual combustion noise and an actual vibration frequency of an actually working engine respectively through the acoustic response transfer function and the vibration response transfer function.
In the above system for testing and analyzing combustion noise in an engine cylinder, the second preparation module 22 is specifically configured to:
taking out the preheating plug of the cylinder, and installing the pressure sensor at the original position of the preheating plug, wherein the pressure sensor extends into the cylinder;
the vibration sensor is arranged on the surfaces of the cylinder body, the cylinder head and the cylinder head cover of the cylinder, and the oil pan and the front end belt head cover of the engine.
In the above system for testing and analyzing combustion noise in an engine cylinder, the system for testing and analyzing combustion noise in an engine cylinder further includes a third preliminary module 52, and the third preliminary module 52 is specifically configured to:
placing a piston in the cylinder at top dead center to maximize a volume of a combustion chamber in the cylinder;
the engine is placed in the mid-air by an elastic rope and a hook.
In the above system for testing and analyzing combustion noise in an engine cylinder, the system for testing and analyzing combustion noise in an engine cylinder further includes an adjusting module 62, and the adjusting module 62 is specifically configured to:
and adjusting the pressure of the combustible mixed gas entering the cylinder through the combustible mixed gas injection pipe so as to control the combustion pressure and the combustion pressure rise rate in the cylinder.
In the above system for testing and analyzing combustion noise in an engine cylinder, the formula for calculating the actual combustion noise of the engine working actually through the acoustic response transfer function is as follows:
the acoustic response transfer function x pressure of the cylinder in actual operation = actual combustion noise of the engine in actual operation;
the formula for calculating the actual vibration frequency of the actually working engine through the vibration response transfer function is as follows:
the vibration response transfer function x pressure of the cylinder actually operated = the actual vibration frequency of the engine actually operated.
In summary, the method and system for testing and analyzing the combustion noise in the engine cylinder in the above embodiments of the present invention can successfully separate the combustion noise and the mechanical noise of the engine, and the testing method provided by the present application is performed on a non-operating engine, so that there is no mechanical noise, and further the present application can obtain an acoustic response transfer function under a pure combustion excitation and a vibration response transfer function of each component under a combustion excitation, and finally calculate the actual combustion noise and the actual vibration frequency of the engine that actually works through the acoustic response transfer function and the vibration response transfer function.
The above modules may be functional modules or program modules, and may be implemented by software or hardware. For a module implemented by hardware, the modules may be located in the same processor; or the modules can be respectively positioned in different processors in any combination.
The logic and/or steps represented in the flowcharts or otherwise described herein, e.g., an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.
More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. An in-cylinder combustion noise test analysis method for an engine, characterized by being applied to the engine, the method comprising:
installing a combustible mixed gas injection pipe at an original oil nozzle of the engine, wherein the combustible mixed gas injection pipe is used for injecting combustible mixed gas into a cylinder of the engine, and the combustible mixed gas comprises propane and oxygen;
arranging a pressure sensor and a vibration sensor on the engine, and arranging microphones around and below the engine;
igniting combustible mixed gas injected into the cylinder through a spark plug at preset intervals, and respectively collecting pressure intensity in the cylinder, vibration frequency of the cylinder and audio frequency generated by the engine;
and calculating an acoustic response transfer function under the unit combustion pressure of the cylinder according to the pressure and the audio, and calculating a vibration response transfer function under the combustion excitation of the engine according to the vibration frequency, so as to calculate the actual combustion noise and the actual vibration frequency of the actually working engine respectively through the acoustic response transfer function and the vibration response transfer function.
2. The in-cylinder combustion noise test analysis method of an engine according to claim 1, characterized in that: the step of arranging a pressure sensor and a vibration sensor on the engine includes:
taking out the preheating plug of the cylinder, and installing the pressure sensor at the original position of the preheating plug, wherein the pressure sensor extends into the cylinder;
the vibration sensor is arranged on the surfaces of the cylinder body, the cylinder head and the cylinder head cover of the cylinder, and the oil pan and the front end belt head cover of the engine.
3. The in-cylinder combustion noise test analysis method of an engine according to claim 1, characterized in that: prior to the step of arranging microphones around and below the engine, the method further comprises:
placing a piston in the cylinder at top dead center to maximize a volume of a combustion chamber in the cylinder;
the engine is placed in the mid-air by an elastic rope and a hook.
4. The in-cylinder combustion noise test analysis method of an engine according to claim 1, characterized in that: after the step of igniting the combustible mixture gas injected into the cylinder by the spark plug at preset intervals and respectively collecting the pressure in the cylinder, the vibration frequency of the cylinder and the audio frequency generated by the engine, the method further comprises the following steps:
and adjusting the pressure of the combustible mixed gas entering the cylinder through the combustible mixed gas injection pipe so as to control the combustion pressure and the combustion pressure increase rate in the cylinder.
5. The in-cylinder combustion noise test analysis method of an engine according to claim 1, characterized in that: the formula for calculating the actual combustion noise of the actually working engine through the acoustic response transfer function is as follows:
the acoustic response transfer function x pressure of the cylinder in actual operation = actual combustion noise of the engine in actual operation;
the formula for calculating the actual vibration frequency of the actually working engine through the vibration response transfer function is as follows:
the vibration response transfer function x pressure of the cylinder actually operated = the actual vibration frequency of the engine actually operated.
6. An in-cylinder combustion noise test analysis system for an engine, applied to an engine, the system comprising:
the fuel injection device comprises a first preparation module, a second preparation module and a fuel injection module, wherein the first preparation module is used for installing a combustible mixed gas injection pipe at an original fuel injection nozzle of the engine, the combustible mixed gas injection pipe is used for injecting combustible mixed gas into a cylinder of the engine, and the combustible mixed gas comprises propane and oxygen;
the second preparation module is used for arranging a pressure sensor and a vibration sensor on the engine and arranging microphones on the periphery and the lower part of the engine;
the acquisition module is used for igniting combustible mixed gas injected into the cylinder through a spark plug at preset intervals, and respectively acquiring pressure intensity in the cylinder, vibration frequency of the cylinder and audio frequency generated by the engine;
and the calculation module is used for calculating an acoustic response transfer function under the unit combustion pressure of the cylinder according to the pressure and the audio, calculating a vibration response transfer function under the combustion excitation of the engine according to the vibration frequency, and calculating the actual combustion noise and the actual vibration frequency of the actually working engine respectively through the acoustic response transfer function and the vibration response transfer function.
7. The in-cylinder combustion noise test analysis system of claim 6, characterized in that: the second preparation module is specifically configured to:
taking out the preheating plug of the cylinder, and installing the pressure sensor at the original position of the preheating plug, wherein the pressure sensor extends into the cylinder;
the vibration sensor is arranged on the surfaces of the cylinder body, the cylinder head and the cylinder head cover of the cylinder, and the oil pan and the front end belt head cover of the engine.
8. The in-cylinder combustion noise test analysis system of claim 6, characterized in that: the in-cylinder combustion noise test and analysis system further comprises a third preparation module, wherein the third preparation module is specifically used for:
placing a piston in the cylinder at top dead center to maximize a volume of a combustion chamber in the cylinder;
the engine is placed in the mid-air by an elastic rope and a hook.
9. The in-cylinder combustion noise test analysis system of claim 6, characterized in that: the in-cylinder combustion noise test analysis system of the engine further comprises an adjusting module, wherein the adjusting module is specifically used for:
and adjusting the pressure of the combustible mixed gas entering the cylinder through the combustible mixed gas injection pipe so as to control the combustion pressure and the combustion pressure rise rate in the cylinder.
10. The in-cylinder combustion noise test analysis system of claim 6, characterized in that: the formula for calculating the actual combustion noise of the actually working engine through the acoustic response transfer function is as follows:
the acoustic response transfer function x pressure of the cylinder in actual operation = actual combustion noise of the engine in actual operation;
the formula for calculating the actual vibration frequency of the actually working engine through the vibration response transfer function is as follows:
the vibration response transfer function x pressure of the cylinder actually operated = the actual vibration frequency of the engine actually operated.
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