M-07 Coolant Circuit Pressure Pulsation Test

TESTING?THERMAL MANAGEMENT?& LIQUID-COOLED COOLING CIRCUITS

Cooling and heating systems are vital to electric vehicles, safeguarding key operational components from overheating and ensuring a comfortable ride. To certify their use, components undergo rigorous testing under fluctuating pressure and temperature conditions.

Evaluating their performance and energy consumption through lifelike service tests is also essential. This ensures that air conditioning units and other electronics don't compromise the vehicle's range. Test standards like the M-07 from BMW, VW, or Daimler exemplify the industry's commitment to conducting pressure cycle testing under variable temperature conditions, as well as overpressure and underpressure tests. These standards reflect the high-quality measures necessary to guarantee optimal performance and longevity of electronic vehicles.

Climate control systems must be able to withstand extreme load changes. Instead of testing the load-bearing capacity in proprietary test setups or in real operation, manufacturers can now analyse their products in pressure cycling and function test benches from Poppe + Potthoff Maschinenbau.

Pressure Load Changes for Liquid-Cooled Systems at -40 to +140 °C

In a typical testing scenario, components, such as liquid-cooled power converters or auxiliary heaters for electric vehicles, are placed inside the test chamber of a pressure cycling test bench. This bench is also used for testing valves, hoses, and other hollow bodies expected to endure over 100,000 load changes throughout the vehicle's lifetime, which can be up to 15 years.

The test medium used is typically a water-glycol mixture or pure glycol (e.g., Glysantin G40, G44, G48). Cooling circuit tests occur under conditions ranging from -40°C to +20°C (-40°F to +68°F), while heating circuit tests are conducted between +20°C and +140°C (68°F to 284°F).

We employ a specially devised closed test media circuit that uses pressure to inhibit the formation of vapors, reducing the risk of explosion. Testing can also be carried out within a climate chamber, ensuring a comprehensive evaluation of the Device Under Test (DUT).

The test medium's flow rate can range from 1-50 l/min at pressures from 0.2-12 bar or even higher. Pressure load changes are programmable with a sinusoidal or trapezoidal increase at a testing frequency of 0.2-2 Hz or faster, offering significant flexibility. The test stand is versatile and can accommodate complete systems, assemblies, and components composed of various materials including plastics, metals, and sealants. This allows potential vulnerabilities - such as those around a weld seam - to be detected and optimized early in the development process and throughout production, ensuring high-quality and reliable results.

Learn more about this and other test rigs on our Website.

Performance Data

Temperature ambient:?-40°C to +160°C with rate of change 1,5 K/min

Temperature fluid:?-40°C to +135°C

Test chamber:?with Ex protection for pressure test with coolant (ATEX)

Size of test chamber: 1,500 x 900 x 900 mm (W x H x D)

Flow rate coolant: 0,5 l/min up to 30 l/min adjustable

Test pressure:?dynamic 0,2 to 6 bar with sinus- and trapezoidal curve

Frequency:?up to 2 Hz (further frequencies upon request)

Pressure drop test:?up to 1,000 mbar

Static pressure test:?up to 20 bar with compressed air and adjustable pressure increase

Leak rate test:?0,5 cm3/min

Vacuum testing:?Pressure variation between atmosphere and 18 mbar abs.

E.g. Test Norms:?M-07 - VW8000, GMW14193 4.4.10, MBN 1030, GS 95024-3

E.g. DUTs:?Cooling plates and cooling circuits of radiators, ECUs, HVCH, heat pumps, converters, and more