Judder Test and Analysis for Electric Vehicle

The electric vehicle appears judder phenomenon while emergent accelerating and then loosing the pedal, especially at lower speed. This paper carried out vibro-acoustic test at conditions of emergent accelerating and then loosing the pedal with different velocities, found that: the electric vehicles’ judder frequency primarily focuses on lower frequency band from 10 to 20 Hz, which keeps stable in variable speeds. In addition, all major frame, motor, reducer, differential, tires have varying degrees of judder mutation;the connection between the main and sub-frame mount vibration within the frequency band in the vibration performance is not effective; what’s more, the partial correlation coefficient between tire and the main frame is 0.93. It is proved that the vibration of tire is the main reason causing the electric vehicle judder, while the poor isolation performance of mounts between the main and sub-frame is another main reason. Finally, the author put forward to suggestion for mounts optimization, which is not taken measure on the vehicle, so unable to verify the suggestion is validity. But the study of this paper provides significant guiding for eliminating and improving the electric vehicle judder phenomenon.