Development Of Vehicle Horn Comprehensive Performance Test System

Motor vehicle horn is not only an important safety device,but also one of the noise sources of motor vehicles.With the introduction of compulsory certification standards for automobiles and their parts and components in China,the manufacturers of motor vehicles and parts inspection agencies and manufacturers of automobile horns are in urgent need of a fully functional and reliable vehicle horn performance test device for vehicle horn.Therefore,it is necessary to develop the corresponding equipment to detect the main performance of motor vehicle horn.This article analyzes the classification and working principle of the motor vehicle horn,and introduces the basic acoustic indicators used in the test of horn.Based on the requirements and methods of the test of motor vehicle horn required by the national standards,referring to the advantages and disadvantages of the existing motor vehicle horn test systems both at China and abroad,a motor vehicle horn comprehensive performance test system is designed and developed in this article.This article mainly completed the following work:1.Design the overall structure of the test system,complete the hardware design and software design.Hardware completed horn drive module and horn acoustic performance measurement module.The horn driving module adopts ultra-low internal resistance HEXFET power MOSFET device to realize the loudspeaker drive and on-off control of the large current and low voltage drop,and the measuring circuit of the horn driving voltage and driving current is designed.The horn acoustic performance measurement module adopts I-class microphone and its ICCP(integrated Constant current power)preamplifier.The software uses Visual Basic to write software,based on virtual instrument technology development user interface,based on DSP(Digital Signal Processing)developed the horn basic performance and durability software.2.The horn power drive control part and horn acoustics performance measurement process control part are separately designed and developed,which reduces the interference of horn high power drive to precision sound pressure measurement.3.The durability test scheme of up to six stations(six horns)was designed to realize the alternating work of multi position horn by the sequential time-sharing principle.The real-time measurement and analysis of the performance of the horn were recorded.4.Based on DSP technology,the key performance parameters of loudspeaker are measured,including the base frequency of electric horn,the response delay time of pneumatic or electricpneumatic horn.5.Manage horns,testers and test items through the database.Finally,the function of the test system is validated by experiments.The test system is simple,reliable and effective,and can automatically generate test reports.The system meets the needs of the horn performance evaluation and research of relevant national testing and appraisal agencies and motor vehicle horn manufacturing enterprises in China.