Engine suspension system is a kind of buffer system, which supports the weight of power unit (engine transmission), inhibits the dynamic displacement of power unit caused by external forces including internal reactions, and prevents the excitation force from the engine from being transmitted to the vehicle body.

The powertrain is fixed on the vehicle body and subframe through a three-point suspension. The left suspension and the right suspension are usually compressed rubber suspensions, which are fixed on the vehicle body. The rear suspension on the sub-frame adopts a torsion bar engine bracket to improve the comfort by reducing the vibration in the rotating direction of the engine.

Function of engine suspension system

Automobile is a multi-mass system composed of multiple masses, elastomers and damping. Engine is the main vibration source of automobile, and its vibration is transmitted from powertrain to frame or body through suspension system. Good engine suspension system parameter design is automatic. Therefore, in the characteristics of suspension system, we should first choose to isolate the vibration of the engine itself, that is, to prevent the vibration caused by the unbalanced force of the engine from being excessively transmitted to the car body. This requires that the natural frequency of the suspension system be less than 0.7 times of the excitation frequency when the engine is idling. Generally, the natural vibration frequency of the engine at low idle speed (80050r/min) is about 25-28.3Hz, so the natural vibration frequency of the suspension is required to be less than 17.5- 19.6.

Hertz is usually in the range of 5-20 Hz.

Structural form of suspension

When designing the engine mount, we must fully consider the purpose of the mount, such as supporting quality and limited displacement, and choose a reasonable shape. Suspension has three basic shapes: compression, shearing and tilting.

Great Wall Ito C30 automobile engine suspension is shown in Figure 4-2. Among them, the left suspension and the rear suspension are compressed rubber suspension, and the right suspension is hydraulic suspension.