What Causes Abnormal Noises in a Sedan's Chassis?
1 Answers
The causes of abnormal noises in a sedan's chassis are as follows: 1. Low damping of shock absorbers: Some manufacturers may adjust the hardness of shock absorbers to be relatively low in pursuit of comfort. When the vehicle encounters bumps, the shock absorbers undergo significant compression deformation and rebound well, which can create a floating sensation for passengers. Additionally, vehicle weight and aerodynamic design can cause the car to feel unstable at high speeds, affecting handling quality. 2. Excessive damping component bushings: The damping of connecting components in the vehicle's suspension system also affects driving quality. These damping components include various rubber bushings on the control arms. The main function of rubber bushings is to absorb high-frequency vibrations from the road surface, converting them into heat energy through continuous deformation and compression. However, if there are too many damping components or they are too soft, excessive changes in the suspension's geometric angles can make the chassis feel loose to occupants. 3. Insufficient body structural rigidity: Due to the inherent structural characteristics of unibody construction, there is a certain degree of vibration absorption. However, this does not mean the body is not sturdy or safe, as a vehicle's safety involves many material mechanics indicators, with torsional stiffness being just one of them. Besides ensuring sturdiness, the body itself has some vibration absorption properties, which also affect comfort and handling. Therefore, the solidity of the chassis is somewhat related to the body's torsional stiffness. 4. Road conditions causing suspension damage: The suspension system includes control arms, springs, shock absorbers, and stabilizer bars. When wheels contact the ground and encounter uneven surfaces, vibrations are generated, and the suspension moves up and down to absorb these vibrations. Long-term rapid driving on bumpy roads can accelerate suspension aging, leading to a loose chassis sensation. 5. Aging of control arms and damping components: Most cases of a loose chassis or abnormal noises stem from aging control arms and rubber components connecting to the body. Suspension components moving on bumpy roads for extended periods generate heat at the connection points between control arms and the body. 6. Abnormal noises from stabilizer bar bushings: The stabilizer bar in the suspension is designed to prevent severe body roll and maintain balance, enhancing handling. The bushings on the stabilizer bar also serve as force-bearing points. If these bushings age, the effectiveness of the stabilizer bar can be significantly reduced.
