Road noise is a vital component of vehicle NVH performance. When a vehicle travels, uneven road surface excitations transmit through tires and suspension to the vehicle body, ultimately generating noise inside the cabin. Road noise occupies a critical position in NVH development, especially amid the prevailing popularity of new energy vehicles (NEVs). Without masking noise from internal combustion engines, road noise optimization has become a core segment of NEV NVH development.

New energy vehicles eliminate the noise from conventional internal combustion engines, making the NVH performance of thermal management systems (including heat pump air conditioners, electronic cooling fans, electronic water pumps, wireless charging modules, PM2.5 purification systems and other components) far more perceptible to vehicle occupants.

Compared with battery electric vehicles, extended-range electric vehicles are equipped with multiple excitation sources such as internal combustion engines, intake systems, exhaust systems and generators. The in-cabin vibration and noise induced by the range extender constitute the most critical NVH risk for such vehicles. For the NVH development and matching of range extenders, besides hardware optimization (range extender assembly, mounts, intake and exhaust systems, etc.), vehicle-level calibration strategies for range extender NVH also play a vital role.

The development and tuning of acoustic packages represent a core segment of vehicle NVH performance engineering. Improvements to wind noise, road noise, powertrain noise, electromechanical noise and other noise categories all rely heavily on acoustic package optimization. The development and tuning of acoustic packages aim to isolate or absorb radiated noise via material selection and structural design, optimize vehicle noise transmission paths, and enhance overall cabin quietness.

Wind noise is generated by the interaction between airflow and vehicle body structure during driving. Generally, when the vehicle speed exceeds 80 kph, wind noise becomes the dominant noise source inside the cabin. The development and tuning of automotive wind noise constitute a vital part of full-vehicle NVH performance engineering, requiring cross-disciplinary collaboration among aerodynamics, acoustics, material science and other fields. The core goal is to reduce perceived wind noise and improve riding experience through optimized design of body structure, vehicle sealing systems and acoustic packages.

The mounting system connects the powertrain to the vehicle body and serves as the primary structural-borne noise transmission path for powertrain NVH. Its core functions are as follows: Support the powertrain: The mounting system must bear the weight of the powertrain and prevent excessive static displacement. Restrict powertrain displacement: When the powertrain is subjected to various disturbance forces (braking, acceleration, deceleration, etc.), the mounting system can effectively limit its maximum travel to avoid collision and interference with adjacent components. Vibration isolation: The powertrain mount system shall attenuate and isolate vibrations transmitted from the powertrain to the vehicle frame as much as possible. Meanwhile, it also suppresses vibrations transferred from the frame to the powertrain caused by uneven road surfaces.

The intake system is generally divided into the engine intake manifold assembly and air filter intake system. The exhaust system refers to the complete set of components extending from the engine exhaust manifold all the way to the exhaust tailpipe. Intake & Exhaust NVH is a noise and vibration control technology dedicated to engine intake components (air filter, intake manifold) and exhaust components (muffler, exhaust pipe). Its core objectives include suppressing airflow pulsation noise, combustion-excited vibration and structural radiated noise, as well as striking a balance between acoustic performance and powertrain performance metrics such as intake efficiency and exhaust backpressure regulation.

The transmission system transfers power from the engine to the drive wheels to ensure normal vehicle operation under various driving conditions. Transmission NVH refers to vibration and noise control technology targeting transmission components such as gearboxes, drive axles and drive shafts. Its core goal is to suppress gear meshing noise, bearing vibration and driveline resonance while transmitting power, so as to improve vehicle ride comfort and reliability. As a key performance indicator of the powertrain, transmission NVH directly affects driving smoothness and premium driving perception. Transmission systems of new energy vehicles face greater challenges: the high torque characteristics of electric drives aggravate gear impact, and the quiet operation of motors makes transmission noise much more noticeable.

Digital model review for abnormal noise is a critical task during the engineering design phase of full-vehicle abnormal noise development. NVH engineers conduct multiple rounds of comprehensive digital model inspections across all vehicle systems (chassis, body, interior, exterior, electrical systems, etc.) to fully identify design risks of abnormal noises in each system. They coordinate with product engineers to align on issues and formulate rectification plans. This practice drastically cuts massive cost losses caused by late-stage design changes and ensures on-schedule project development cycles.

Bench abnormal noise testing for subsystems and components is one of the key tuning methods in full-vehicle rattle performance development. Targeted components prone to abnormal noises (instrument panel assembly, auxiliary dashboard assembly, door assembly, seat assembly, seat belt retractor, etc.) are tested separately on dedicated benches via subjective evaluation combined with objective measurement. This enables more detailed and in-depth identification of component-level rattle issues and reduces the workload of full-vehicle abnormal noise tuning.

Full-vehicle road rattle tuning refers to the process of identifying and troubleshooting rattles from all vehicle systems on dedicated characteristic rattle evaluation roads at specified driving speeds. After all abnormal noise issues are identified, the vehicle’s Seat Rattle Index (SRI) is calculated based on the types of characteristic roads where rattles occur and rattle loudness, which is used to judge the overall anti-rattle performance of the vehicle.

Full-vehicle four-post rattle tuning with high & low temperature control refers to the process of identifying and troubleshooting abnormal noises of prototype vehicles under various working conditions within a test facility fully equipped with four-post rig, environmental chamber and semi-anechoic chamber. It covers dynamic road spectrum excitation rattle evaluation, static operation rattle evaluation and acoustic excitation rattle evaluation. The environmental chamber can simulate extreme temperature conditions, and conducting rattle evaluation under diverse thermal environments compensates for the limitations of road test evaluation in temperature simulation.

Customers hold high standards for vehicle anti-rattle performance not only on brand-new vehicles but also after high-mileage operation. Accordingly, the development of full-vehicle durability anti-rattle performance has grown increasingly important year by year. Comprehensive and systematic bench durability combined with rattle testing for complete vehicles represents the most efficient development method for durability-related abnormal noises. Full-scale rattle evaluations carried out at key mileage intervals throughout durability testing can effectively identify rattle defects emerging after aging, helping optimize the vehicle’s long-term anti-rattle performance. Besides, conducting post-durability rattle assessments on other aged test vehicles — including detecting durability-induced rattles and verifying corrective improvements — is another effective approach to enhance anti-rattle performance under high-mileage conditions.

Rattle consistency control for plant off-line vehicles mainly consists of two phases of work. First, during each pre-mass-production stage, identify rattle issues of off-line prototype vehicles (including a small number of design defects), carry out troubleshooting analysis and verification of rectification schemes, and continuously optimize full-vehicle anti-rattle performance through iterative problem detection and resolution. Second, in the mass production phase, track the rattle performance of mass-produced finished vehicles off the assembly line to guarantee stable and consistent anti-rattle quality. Any abnormal deviation shall trigger immediate interception and rectification to prevent defective vehicles from entering the market.

The vehicle body serves as the core response system of the full-vehicle NVH system, and its inherent vibration and noise response characteristics directly determine the overall NVH performance of the complete vehicle. Conducting vehicle NVH performance analysis and optimization in the virtual R&D phase via structural NVH simulation can largely avoid NVH risks triggered by unreasonable body structure design. This drastically cuts down engineering changes and test verification workload in the later stage, and effectively saves various R&D costs including prototype manufacturing, test equipment and labor expenses.

Road noise NVH simulation relies on high-precision full-vehicle finite element models, adopts measured real road surface spectrum as excitation load, and performs computational analysis via professional simulation software. It identifies the generation sources and transmission paths of vibration and noise during vehicle operation, as well as interior vibro-acoustic responses and their impacts on occupants. Based on the simulation results, targeted optimization can be implemented on components including chassis structure, suspension bushing stiffness and body structure, which effectively reduces road noise and road-induced vibration while further improving vehicle ride comfort.

As consumers have increasingly higher requirements for vehicle riding quality, rattling issues in automobiles have attracted growing market attention. During vehicle development, Landtop Technology builds a comprehensive full-vehicle rattle simulation control system for clients. Leveraging finite element simulation technology to analyze the mechanical response spectrum of vehicles under various road conditions, we accurately predict the positions and occurrence probability of rattles, detect and optimize potential rattle risks in advance. This effectively shortens vehicle development cycles and cuts project R&D costs.

Statistical Energy Analysis (SEA) is adopted to predict the performance of acoustic packages, enabling evaluation of acoustic package effectiveness at the design stage and avoiding costly late-stage modifications triggered by post-development defects. Acoustic package simulation has gradually become an indispensable link in NVH development. It improves the vehicle’s acoustic performance while reducing R&D costs and boosting development efficiency.

Wind noise simulation adopts Computational Fluid Dynamics (CFD) and aeroacoustics technologies to predict and optimize exterior aerodynamic noise of vehicles. The core objective of wind noise simulation is to optimize design schemes, reduce exterior aerodynamic noise sources and improve interior riding comfort. Wind noise simulation enables efficient prediction of interior noise, cuts down modification costs in the later development phase and enhances product market competitiveness.

As the components connecting powertrain and vehicle body, mounting systems serve as the primary structural-borne noise transmission path for powertrain NVH. Higher stiffness of mounts benefits durability and transient operating conditions yet impairs vehicle NVH performance. Mount simulation is adopted to strike a balance between durability and NVH performance.

Intake and exhaust systems are core components for reducing airborne noise of internal combustion engines. Simulation-based NVH performance analysis of intake and exhaust systems at the digital prototype stage can mitigate risks during physical vehicle tuning.

The electroacoustic performance of the emergency call system (eCall) is tested and verified mainly in accordance with ITU-T P.1140 Speech communication requirements for vehicle emergency calls, GOST 33468 Audio test standard for ERA-GLONASS on-board emergency call systems, and GB/T 45314-2025 Road vehicles — Performance requirements and test methods for hands-free communication and voice interaction.

As competition in the automotive industry intensifies and high-end acoustic configurations become mainstream for intelligent cockpits, excessive hardware stacking has turned into an industry trend. Against this backdrop, establishing a scientific vehicle-mounted acoustic evaluation system, balancing hardware parameters with actual auditory experience, and linking objective testing results to subjective perception have become core challenges in the field of intelligent cockpit acoustics.

Within the modern aviation pilot training system, high-end simulators equipped with six-degree-of-freedom motion platforms, ultra-wide field-of-view visual systems and high-fidelity acoustic environments can undertake 70% to 90% of training tasks that would otherwise require real flights. It is worth emphasizing that a high-fidelity acoustic environment is far more than simple audio playback; it refers to dynamic acoustic simulation technology that performs dynamic signal processing based on pilot control inputs and actual simulated operating conditions.