Diagnosis and Elimination of Vehicle Lateral Shake in Passenger Car through Modification of Driveshaft Joints and Engine Mount System

Vehicle lateral shake during take-off is sensitively felt by customers when the vehicle is driven at a low speed under drive away acceleration. The take-off shudder is complained by customers during 1st and 2nd gear take off. Under an engine torque and half shaft angle, the drive-away shudder usually occurs during acceleration to a specific low speed at 1200 to 1600 engine rpm, which makes the vehicle shake severely. A thorough investigation with possible design optimization of mounting system, drive shaft joint and lubrication is done to reduce the lateral vibration. This paper focuses on a passenger car, the take-off shudder of which occurs at a speed between 20 km/h and 30 km/h. The test vehicle is a monocoque construction with front wheel drive east west engine. Vehicle lateral shake is observed during the low gear power train run up in Wide Open Throttle (WOT) condition. The lateral shake is felt predominantly on the front half of the vehicle which is easily perceivable by passenger.

The paper discusses the measurement and analysis procedures to identify the root cause of shudder. Different modifications are tried out based on the analysis and an optimum solution is selected. The selected modification does not have any adverse effect on other Noise Vibration and Harshness (NVH) attributes.