How do you minimize engine vibration and harshness with engine mounts?

1 What are engine mounts?

Engine mounts are devices that connect the engine to the chassis or body of the vehicle. They have two main functions: to support the weight and alignment of the engine, and to isolate and dampen the engine vibrations from the rest of the vehicle. Engine mounts are usually made of rubber, metal, or a combination of both, and they can have different designs and configurations depending on the type and size of the engine, the layout of the vehicle, and the desired NVH characteristics.

2 How do engine mounts isolate vibrations?

Engine mounts isolate vibrations by creating a flexible connection between the engine and the chassis. The rubber or metal components of the engine mounts act as springs and dampers, absorbing and dissipating the energy of the vibrations. The engine mounts also have different stiffness and damping properties in different directions, depending on the frequency and amplitude of the vibrations. For example, engine mounts can be stiffer in the vertical direction to support the weight of the engine, but softer in the lateral and longitudinal directions to allow some movement and isolation.

3 How do engine mounts dampen vibrations?

Engine mounts dampen vibrations by converting the kinetic energy of the vibrations into heat. The rubber or metal components of the engine mounts deform and dissipate the energy as friction or hysteresis. The amount of damping depends on the material, shape, and size of the engine mounts, as well as the temperature and loading conditions. The more damping the engine mounts have, the less vibration is transmitted to the chassis and the cabin, but also the more heat is generated and the faster the engine mounts wear out.

4 How do engine mounts tune vibrations?

Engine mounts tune vibrations by changing the natural frequency and mode shape of the engine-chassis system. The natural frequency is the frequency at which the system vibrates when disturbed by an external force. The mode shape is the pattern of displacement and deformation of the system when vibrating at a natural frequency. By adjusting the stiffness and damping of the engine mounts, you can change the natural frequency and mode shape of the system to avoid resonance or amplification of vibrations. For example, you can tune the engine mounts to have a natural frequency that is higher or lower than the dominant frequency of the engine, or to have a mode shape that is less sensitive to the engine excitation.

5 How do you choose the best engine mounts?

Choosing the best engine mounts for your vehicle depends on several factors, such as the type and size of the engine, the layout and weight distribution of the vehicle, the driving conditions and preferences, and the NVH targets and standards. You need to consider the trade-offs between performance, comfort, durability, and cost when selecting the engine mounts. You also need to test and validate the engine mounts under different scenarios and environments, using simulation tools, laboratory experiments, and field trials. You can use various metrics and methods to evaluate the engine mounts, such as frequency response, modal analysis, vibration transmissibility, sound pressure level, and subjective ratings.

6 How do you maintain the engine mounts?

Maintaining the engine mounts is important to ensure the optimal performance and longevity of your vehicle. You need to inspect the engine mounts regularly for any signs of damage, wear, or deterioration, such as cracks, leaks, deformation, corrosion, or looseness. You also need to replace the engine mounts when they fail or exceed their service life, which can vary depending on the type and quality of the engine mounts, the usage and maintenance of the vehicle, and the environmental conditions. You can follow the manufacturer's recommendations or consult a professional mechanic to determine the best time and procedure to replace the engine mounts.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?