Automotive cooling system testing

Durability testing of cooling systems calculates how long a component of a cooling system can safely and reliably perform its function. The component is exposed to a number of relevant external factors (such as internal pressure, temperature, and flow). The life cycle of a component can thus be represented via time lapse in the laboratory. Our durability testing methods use several fluids: coolant, oil, and air.

The cooling system components built into vehicles go through an ageing process which is influenced by factors such as temperature, coolant, oil, static pressure and flow. Ageing tests calculate how much each factor influences the ageing of the cooling system components.

The static pressure and temperature tests for cooling systems calculate the ageing of components when influenced by temperature, pressure and fluids (e.g. coolant, oil, air etc.) and, as such, often forms part of the ageing test.

This test evaluates the long-term performance of a cooling system’s components. They are exposed to dynamic pressure changes as well as impacted by temperature and flow. Coolant, oil, and air are used as the fluids.

The acronym PVT stands for pressure, vibration and temperature. During this test, cooling system components are exposed to three factors at the same time: dynamic pressure changes, different temperatures, flow and vibration or motion. With this, the PVT test simulates the various components when exposed to several influencing factors and can predict reliable numbers about their durability. PVT tests can be performed using coolant, oil, air and other fluids. Some standard test procedures include the regulations SAE J2044, SAE J2045, DIN 73379 and numerous regulations from notable OEMs.

The temperature change test investigates the behaviour of a cooling system’s component under defined temperature conditions ranging from -70 °C to +180 °C. The component is constantly monitored as the temperature is switched between these two extremes to ascertain the component’s operational reliability. Temperature gradients up to 6 K/min and with temperature chambers with volumes ranging from 0.8 m³ to 3.5 m can be simulated. TÜV SÜD further has chambers according to the requirements of the European Explosion Protection Directive ATEX for testing.

The climatic test for cooling system is similar to the temperature change test: components of the cooling system are exposed to specific temperatures between -40 °C and +180 °C. The relative humidity, ranging from 0 to 98 %, is an additional factor. In our modern climate chambers volumes of 0.8 m³ to 3.5 m³are possible. They offer temperature gradients of up to 4 K/min.

The impact of ageing on the cooling system’s hoses and pipes and their systems is measured by exposing them to long-term influences such as temperature and various fluids including coolant, oil, and air. Additional variables considered are static pressure and flow.

While testing the material of the cooling system’s components a comprehensive range of leak tests, burst pressure tests, compression and tensile tests, ball-drop tests, cold impact tests and fire tests in the laboratory are performed. These tests help calculate the reliability, safety, and quality of the materials and show whether the cooling system components meet the legal requirements and standards.

Each test that involves flow of fluid through a component is considered a flow test. They tend to include the use of temperature, fluid (e.g., coolant, oil etc.), static pressure and flow. Typical flow tests include erosive flow testing as well as an internal corrosion test.

Pressure impulse testing exposes cooling system components to high-frequency, dynamic changes in pressure. Additional factors include temperature – ambient and of the component itself – and flow rate. Possible fluids here include coolant, oil and others.

Temperature shock testing exposes the components of the cooling systems to fluids (like coolant, oil etc.) that are heated up to a pre-defined temperature. It is then alternated between high and low temperatures within short intervals. Due to the extreme speed and extreme change in temperature this is called temperature shock.

The erosion test is a form of flow test in which specific dirt particles are added to the fluid flowing through the cooling system’s component, thus allowing conclusions to be drawn about the component’s erosion behaviour.

During this test the cooling system components are flushed with a mixture containing specific salts. The test provides reliable data about the corrosion behaviour of the components.

These tests are specially designed to investigate the endurance limit of a component when it is exposed to factors including temperature, pressure, and multi-axial motion. TÜV SÜD uses a specially designed robot to achieve the multi-axial motion for this test.