The Vibrational Improvement of the Two-Piece Driveline of the Passenger Car

The Iran Khodro's RD 1600 (a rear wheel drive, medium-sized saloon car equipped with a two-piece, parallel-crossed driveline) suffered from a harsh driveline vibration in 2nd and 3rd gears during acceleration. The vibration occurred between the speeds of 20 and 30 km/h with a maximum vibration occurring at 25 km/h. Various modifications in the driveline geometry, including raising the prop shaft center bearing and adjusting the phase angle of the yokes, were performed to achieve an acceptably low disturbance level. Graphical and mathematical procedures were applied to the driveline for secondary couple effects and torsional vibration. An objective test was performed in different operating conditions to measure the sensitivity of the vehicle to driveline modifications. Finally, tests were conducted to assess the level of vibration and interior noise under normal road conditions.