An Overview of Hydraulic Engine<br>Mount Technology in Passenger<br>Vehicle NVH Control<br>1. Introduction<br>In modern passenger vehicle development, ride comfort has become one of the key indicators of<br>overall vehicle quality. Noise, Vibration and Harshness (NVH) performance has a direct impact on<br>driving comfort and the perceived refinement of a vehicle. As one of the main sources of vibration, the<br>engine plays a critical role in NVH behavior, and its vibration control largely depends on the design of<br>the engine mounting system.<br>Engine mounts are not only responsible for supporting and positioning the engine, but also serve as an<br>important barrier that isolates vibration and reduces structure-borne noise. As NVH requirements<br>continue to increase, traditional rubber engine mounts have shown certain limitations under specific<br>operating conditions. As a result, hydraulic engine mounts have been increasingly adopted in<br>passenger vehicles.<br>2. Engine Vibration Characteristics and NVH Issues<br>During operation, the engine continuously generates vibration due to combustion forces, rotational<br>motion, and reciprocating inertia forces. If these vibrations are transmitted directly to the vehicle body,<br>they may cause steering wheel shake, low-frequency cabin noise, and a general reduction in ride<br>comfort.<br>In typical passenger vehicle usage, idle and low-speed conditions are particularly sensitive. At these<br>operating points, vibration excitation is concentrated and vibration amplitudes are relatively high,<br>placing greater demands on the low-frequency isolation capability of the mounting system. Traditional<br>rubber mounts, which rely mainly on material elasticity, often struggle to balance load-bearing<br>stiffness and vibration isolation performance.

3. Working Principle of Hydraulic Engine Mounts<br>Hydraulic engine mounts are composite vibration isolation devices that combine rubber elastic<br>elements with hydraulic damping structures. Their basic principle is to reduce engine vibration by<br>combining rubber deformation with fluid motion.<br>When the engine vibrates, the rubber element deforms first. The internal fluid then flows between<br>chambers through specific passages, creating damping effects that convert vibration energy into heat<br>and dissipate it. Through proper structural design, hydraulic engine mounts can achieve effective<br>damping within targeted frequency ranges.<br>This design gives hydraulic engine mounts a clear advantage in controlling low-frequency vibration,<br>making them particularly effective in improving vibration performance during idle and vehicle launch<br>conditions.<br>4. Advantages of Hydraulic Engine Mounts in Passenger<br>Vehicle NVH<br>First, under idle conditions, hydraulic engine mounts can significantly reduce the transmission of<br>engine vibration to the vehicle body. This helps improve steering wheel feel and cabin comfort, while<br>also enhancing overall vehicle quietness.<br>Second, during dynamic driving conditions such as acceleration and deceleration, hydraulic mounts<br>are able to maintain a good balance between support stiffness and vibration isolation. This allows the<br>mounting system to adapt better to changing operating conditions.<br>In addition, low-frequency vibration is a major contributor to interior noise. By effectively reducing<br>structure-borne vibration, hydraulic engine mounts also help improve the acoustic comfort of the<br>vehicle, resulting in a more refined and balanced driving experience.<br>In practical applications, the performance of hydraulic engine mounts depends heavily on system-level<br>vehicle matching. Mount parameters must be designed in coordination with engine characteristics,<br>body structure stiffness, and overall mounting layout<br>5. Design Considerations in Engineering Applications<br>.<br>Because hydraulic mounts contain fluid and sealing components, higher requirements are placed on<br>durability and reliability. Long-term vibration exposure and harsh environmental conditions make<br>material stability and sealing performance key design concerns.