A car can be divided into four parts: the engine, chassis, electrical equipment, and body. With the emergence of electric vehicles, new energy vehicles, and self-driving cars, electrical equipment plays an increasingly important role in the development of automotive technology. The performance of automotive electrical and electronic equipment directly affects the realization of various technologies and functions of the car. ISO 16750 is a standard developed to ensure the normal operation of automotive electronic equipment and components in various environments. In this article, we will focus on the ISO 16750-4 standard.
ISO 16750
The ISO 16750 series is a set of internationally recognized test standards developed by the International Organization for Standardization specifically for automotive electrical and electronic equipment. This series has established a range of test standards and requirements based on the environmental conditions that vehicle electrical and electronic equipment may encounter in actual use.
ISO 16750-1, Road vehicles- Environmental conditions and testing for electrical and electronic equipment-Part 1: General
IS0 16750-2, Road vehicles -Environmental conditions and testing for electrical and electronic equipment-Part2: Electrical loads
ISO 16750-3, Road vehicles -Environmental conditions and testing for electrical and electronic equipment-Part 3: Mechanical loads
IS0 16750-4, Road vehicles -Environmental conditions and testing for electrical and electronic equipment-Part 4: Climatic loads
IS0 16750-5, Road vehicles -Environmental conditions and testing for electrical and electronic equipment-Pan 5: Chemical loads
ISO 16750-4 Climatic Tests
Tests at constant temperature
Low-temperature tests
Storage test: This test simulates the exposure of the systems/components to low temperatures without electrical operation(e.g. during transportation). The failure mode is a malfunction due to insufficient frost resistance, e.g. the freezing of a coolant.
Operation test: This test simulates the exposure of the systems/components to low temperatures with electrical operation. The failure mode is an electrical malfunction caused by low temperature, e.g. the freezing of capacitors with liquid electrolyte.
High-temperature tests
Storage test: This test simulates the exposure of the systems/components to high temperatures without electrical operation((e.g. during transportation). The failure mode is insufficient heat resistance, e.g. warping of plastic housings.
Operation test: This test simulates the exposure of the systems/components to high temperatures with electrical operation. The failure mode is an electrical malfunction caused by high temperature, e.g. thermal degradation of components.
Temperature step test
This test checks the mechanical and electrical device for malfunctions (including failure to change properly between different operating modes) which may occur within a small section of the operating temperature range.
Temperature cycling tests
Temperature cycle with specified change rate
This test simulates varying temperatures with electrical operation of the systems/components, e.g. during the use of the system/component at changing ambient temperature. The failure mode is an electrical malfunction during temperature.
Rapid change of temperature with specified transition duration
This is an accelerated test which simulates a very high number of slow temperature cycles in the vehicle. The acceleration is possible due to a much higher temperature change rate and a bigger temperature change in one cycle in comparison with real vehicle stress. The failure mode is an electrical malfunction and/or mechanical failure due to cracking of materials or seal failures caused by ageing and different temperature expansion coefficients.
Cold water shock tests
The purpose of the test is to simulate the thermal shock induced by cold water splashing over a hot system/component. This happens when driving on wet roads in winter and applies to products in the splash areas or the vehicle. The failure modes are a mechanical cracking of materials or seal failures caused by different temperature expansion coefficients.
Salt spray tests
Corrosion test
This test checks the resistance of materials and surface coatings of a system/component to de-icing agents.This test generates corrosion similar to reality,The failure mode is corrosion.
Leakage and function test
This test checks the resistance of a system/component to salt mist and salt water on winter streets. The failure mode is an electrical malfunction due to leakage currents caused by the ingress of salt water.
Salt spray active test for rotating machines with open housing
This test checks the resistance of a system/component to salt mist and salt water on winter streets. The test is used for rotating machines with open housings (e.g.alternators,integrated starter generators). It simulates the corrosion load during operating of the component.The failure mode is corrosion, especially on energized parts.
Salt spray combined cycle test
This test checks the resistance of materials and surface coatings of a system/component to salt mist and salt water on streets in winter. The failure mode is corrosion and/or electrical malfunction.
Cyclic corrosion test
This test checks the resistance of materials and surface coatings of a system/component to salt mist and salt water on streets in winter in diverse humidity conditions. This test generates corrosion simulating actual use in the market with precise control of temperature and humidity. The failure mode is corrosion (e.g. cosmetic corrosion, crevice corrosion and galvanic corrosion).
Humid heat, cyclic tests
(Damp heat cyclic test, Composite temperature/humidity cyclic test, Dewing test)
These tests simulate the use of the systems/components under cyclic high ambient humidity. The failure mode is an electrical malfunction caused by leakage current and corrosion.
Damp heat, steady state test
This test simulates the use of the systems/components under steady high ambient humidity. The failure mode is an electrical malfunction caused by leakage current and corrosion.
Condensation test
This test simulates condensation by rapid change of temperature and humidity. Such condensation can occur when the vehicle moves in a warm garage from a cold outside or when opening vehicle windows hot and humid air flows into the cabin cooled and dried by air conditioner. The failure mode is an electrical malfunction caused by leakage current and corrosion.
Corrosion test with flow of mixed gas
This test simulates the use of the systems/components in the presence of corrosive gases, e.g. in polluted atmospheres. The failure mode is an electrical malfunction caused by conductive corrosion or corrosive product on the surface of electrical/electronic components. This test is relevant for plug contacts and open switching contacts. Another failure mode is the penetration of protective (paint) coatings with subsequent corrosion of the structures below.
Solar radiation test
This test simulates the use of the systems/components in an environment with long term exposure to solar radiation. This test is applied to surface treatment (e.g. protective coating), paint marking and labelling pasted on the surface of systems/components mounted in places affected by solar radiation.
Dust test
This test simulates a dust pumping effect caused by temperature changes inside the housing of the systems/components, due to intermittent electrical operation. The failure mode is an electrical or mechanical malfunction caused by dust, e.g. on the surface of electrical contacts.
Atmospheric pressure test
This test simulates an electric phenomenon known as “electric discharge”, particular to high voltage use under low atmospheric pressure. This test applies to only voltage class B components.
The purpose of this test, which consists in measuring an extremely small amount of discharge, is to detect potential defectiveness likely to shorten the durable life, and which is hardly detectable by measuring withstand voltage or insulation resistance.
The above serves as an introduction to ISO 16750-4, which includes test items related to temperature and humidity. These tests can be conducted using KOMEG’s climatic test chambers.