Automatic Test System Of Common Rail ECU Based On PXI And Virtual Instrument

High pressure Common Rail(CR)fuel injection system can greatly improve the diesel engine power,economy,and effectively reduce emissions.The CR diesel has become the first choice due to the stringent emission regulation.As the core of CR,Electronic Control Unit(ECU)is of great importance.In order to ensure the reliability of ECU production,reduce the test workload and shorten the development cycle,it is necessary.to develop an efficient and intelligent ECU automatic test system.The functions,calibration protocol and calibration files of the CR ECU was analyzed to complete the communication between the test system and the ECU to be tested.The automatic test system was developed based on the virtual instrument technology.The test principle is to simulate the ECU input signal and read the corresponding measurement through CAN communication function to judge whether the input circuit is normal;change the calibration value of the output signal,collect the output signals to judge whether the output circuit is normal.The hardware part of the test system was built on the platform of NI PXI.The selection of test boards was completed based on the statistics of the input/output signals of ix-cylinder CR diesel engine.The automatic test system could perform automatic control of the fixture,power management,program downloading,simulation of the input signals,collect the output signals and fault injection.Finally the fixture and interface was developed to meet the test of several ECUs.According to the advantages of Labview and TestStand software,the test system software,which has simple and intuitive user interface,was developed in three layers.The main difficulties in the process were described in detail.Finally,Minitab software was used to analyze the repeatability,reproducibility,linearity and stability of the automatic test system based on the test date.