What environmental test chambers are used for automotive lamp reliability testing?

Vehicles carry thousands of electronic components, whose reliability directly impacts driving safety, necessitating extensive environmental testing. Certain automotive lamps endure relentless exposure to outdoor conditions year after year, day after day, facing challenges that speak for themselves.

Headlight Inspection Coverage:

In the automotive sector, vehicle lighting serves as a critical component for ensuring driving safety. Continuously exposed to complex outdoor environments, its reliability plays a pivotal role in vehicle operational safety. Consequently, the industry has established stringent standards. For instance, Volkswagen's VW80101 - 2009 “General Test Conditions for Automotive Electrical and Electronic Components” sets exceptionally rigorous environmental requirements for automotive lighting. Only after passing a series of intricate and rigorous tests do automotive lamps qualify for market entry. Below is a detailed introduction to some of the core test chambers required for these critical evaluations:

Headlight Test Chamber

Regarding headlight testing, TEMAK standard headlight test chamber can simulate both the headlight surface (outdoor environment) and the headlight rear (engine compartment environment). The left section simulates the outdoor environment for the headlight surface (temperature, humidity, rainfall, wind speed, and illumination), while the right section simulates the engine compartment environment for the headlight rear (temperature, humidity, and wind speed).

Temperature & Humidity Test Chamber

Temperature and humidity testing simulates the extreme temperature fluctuations automotive lamps may encounter during actual use. Specifically, the lower operating limit temperature TuB is precisely set at -40°C, simulating the extreme cold environments of frigid regions. Automotive lamps must function normally and maintain stable performance at this temperature. The upper operating temperature ToB is set at 70°C, corresponding to conditions where the vehicle operates for extended periods in hot weather. Factors such as heat conduction from the engine compartment and direct sunlight exposure cause the ambient temperature around the lamp to rise significantly. The entire test requires completing 30 full cycles, with each cycle demanding a constant-speed temperature shift between TuB and ToB. This testing comprehensively evaluates whether the vehicle's internal electronic components, sealing materials, and optical parts experience performance degradation, material aging, or seal failure under frequent extreme temperature switching. It ensures stable and reliable operation under all harsh temperature conditions.

High-Low Temperature Test Chamber or Temperature & Humidity Test Chamber

Automotive lamps must undergo not only the constant damp heat test mentioned above, but also the alternating damp heat test.What is the difference between constant humidity and alternating humidity? The gradient temperature test focuses on simulating the gradual heating and cooling process of automotive lamps in natural environments. At the start of the test, the temperature decreases in 5°C increments from +20°C down to TuB. After each temperature gradient change, sufficient time must be allowed for the test specimen to fully reach the new temperature. This is because different components of automotive lamps, made of varying materials, conduct heat at different rates and require time to achieve thermal equilibrium. The gradual cooling allows detection of whether components maintain proper alignment in progressively colder conditions, and whether temperature changes cause stress deformation or alterations in electrical performance. Subsequently, the temperature is raised from TuB to ToB using the same 5°C gradient, again allowing the specimen to reach the new temperature at each stage. This comprehensive and meticulous process simulates the gradual temperature variations automotive lamps experience across different seasons, time periods, and driving conditions. By monitoring lamp performance at each temperature stage, it enables a thorough evaluation of reliability and stability under natural temperature gradients.

Thermal Shock Test Chamber

Temperature shock testing is conducted under specific operating conditions without connecting the cable to the test specimen, requiring strict adherence to the specified process standards for 100 cycles.What does a thermal shock test chamber for automotive parts look like?

The specific thermal shock test procedure is as follows:

Initial Temperature Setting

The test cycle's initial temperature is set to room temperature, strictly controlled at (23 ± 5)°C. This temperature simulates the ambient conditions experienced by vehicle headlights when starting under normal indoor parking or mild climate conditions.

Rapid Heating Phase

The temperature must rapidly increase from the initial setting to 70°C, with the entire temperature change completed within ≤10 seconds. This rapid heating process simulates the scenario where, after starting in cold weather, heat from the engine compartment rapidly transfers to the headlight area within a short time, causing a sharp rise in headlight temperature. At this high temperature of 70°C, the automotive lamp must be continuously stored for 30 minutes to test its stability under high-temperature conditions. This includes evaluating the heat dissipation performance of electronic components, the high-temperature resistance of plastic parts, and the thermal stability of optical materials.

Rapid Cooling Phase

Immediately following, the temperature must rapidly decrease from 70°C to -40°C, with the temperature change time also ≤10 seconds. This rapid cooling simulates the scenario where a vehicle, after driving in hot weather, suddenly enters a cold environment (such as entering an underground parking garage or tunnel), causing the headlight temperature to drop sharply in an instant. At -40°C, the automotive lamp must be stored for 45 minutes to evaluate its performance in low-temperature conditions. This tests aspects like the cold start capability of electronic components, material cold resistance, and whether sealing performance is compromised by low temperatures. This 100-cycle thermal shock test effectively evaluates the automotive lamp's ability to withstand rapid temperature changes, ensuring reliable operation under various sudden temperature fluctuations encountered during actual use.

Salt Spray Test Chamber

Salt spray testing is a critical component of environmental durability testing for automotive headlights, designed to evaluate their resistance to salt spray corrosion, particularly targeting the headlight's metal components.As can be seen in the automobile body salt spray test requirements，salt spray testing is critical to automotive reliability. By spraying a sodium chloride solution in a salt spray chamber, it simulates the corrosive effects of salt spray environments on vehicle headlights, ensuring they maintain functional and aesthetic integrity throughout prolonged use.

The standards and procedures for automotive headlight reliability testing vary across different countries, regions, and automakers. Below is an overview of the general standards and procedures:

Testing Standards

International Standards

ECE Standards

Regulations such as ECE R3 and R48, developed by the United Nations Economic Commission for Europe (UNECE), establish detailed specifications for automotive lighting systems regarding light distribution characteristics, mounting positions, and light color. These regulations also address reliability-related requirements, including the mechanical strength and vibration resistance of lighting components.

ISO Standards: Standards established by the International Organization for Standardization (ISO), such as the ISO 16750 series, specify environmental conditions and test methods for electrical and electronic equipment in road vehicles. These standards include reliability testing requirements for automotive lamps under environmental factors including temperature, humidity, and vibration.

Enterprise Standards

Automotive Manufacturer Standards

Major automakers typically establish stricter internal corporate standards based on international and national standards. For example, Volkswagen's VW80101 series standards and Daimler's relevant standards impose more detailed and specific requirements for headlight reliability testing to ensure products meet their brand's quality and performance benchmarks.

Testing Process

Preliminary Preparation

Sample Preparation

In accordance with the test requirements, prepare a sufficient number of vehicle light samples to ensure they are representative and cover products from different batches and models.

Test Equipment Calibration

Calibrate various testing equipment, such as high-low temperature chambers, vibration testers, and salt spray test chambers, to ensure their measurement accuracy and performance meet testing requirements.

Test plan formulation

Develop a detailed testing plan based on testing standards and the characteristics of the vehicle lights, clearly defining test items, test conditions, test sequence, and acceptance criteria.

Environmental Adaptability Testing

Temperature Testing

Includes high-temperature storage tests, low-temperature storage tests, temperature cycling tests, and thermal shock tests. For instance, in a high-temperature storage test, the headlight is placed in a high-temperature environment (e.g., 85°C) for a specified duration (e.g., 48 hours) to observe whether deformation, discoloration, or performance degradation occurs.

Humidity Testing

Conduct constant humidity and heat tests, alternating humidity and heat tests, and other procedures to simulate the use of automotive lamps in humid environments. For example, in a constant humidity and heat test, the lamp is placed in an environment with a temperature of 40°C and relative humidity of 90% for a specified duration (such as 96 hours). The test evaluates whether the lamp's insulation properties, optical performance, and other characteristics are affected.

Dust and Rain Resistance Testing

Dust and Rain resistance tests are conducted in accordance with the IP (Ingress Protection) rating standards. For example, to meet the IP67 rating requirement, the vehicle lamp must completely prevent dust ingress during the dust test. In the water resistance test, after being submerged in 1 meter of water for 30 minutes, no water ingress is permitted inside the lamp, and it must maintain normal performance.

Mechanical Performance Testing

Vibration Testing

The headlight is mounted on a vibration table and tested at specified vibration frequencies, amplitudes, and durations to simulate the vibration environment encountered during vehicle operation. This evaluates the structural integrity of the headlight and checks whether internal components become loose, detach, or sustain damage due to vibration.

Impact Testing

Apply a specific energy impact to the headlight using an impact testing machine to evaluate its resistance to sudden collisions. Observe whether the headlight exhibits cracking, damage, or other failures.

Mechanical Durability Testing

Repeatedly operate mechanical components such as switches and adjustment mechanisms to test their mechanical lifespan. For example, switches undergo over 100,000 on/off cycles to ensure reliable performance during prolonged use.

Electrical Performance Testing

Illumination Test

Conduct extended illumination tests to verify stable light output performance, checking for flickering or extinguishing. Typically, high beams, low beams, and other functions must operate continuously for a specified duration (e.g., 500 hours) without failure.

Electrical Parameter Testing

Measure the operating voltage, current, power, and other electrical parameters of the lamp to ensure they remain within specified ranges. Verify that variations in electrical parameters under different environmental conditions meet requirements.

Electromagnetic Compatibility Testing

Includes electromagnetic emission testing and electromagnetic immunity testing. This ensures the lamp does not interfere with surrounding electronic equipment during operation while maintaining proper function in various electromagnetic environments.

Optical Performance Testing

Light Distribution Testing

In an optical test chamber, light distribution testing equipment measures the intensity distribution and beam angles of various vehicle lamp functions—including high beams, low beams, and turn signals—to ensure compliance with relevant standards. This guarantees optimal illumination performance and driving safety.

Colorimetric Performance Testing

Measures the light color of vehicle lamps, including color temperature and chromaticity coordinates for white light, as well as the colorimetric range for other colored lights (e.g., amber for turn signals, red for brake lights). This ensures light colors meet standard requirements with pure and uniform hues.