Heatable modular test system

Thanks to the modular layout, the individual components of the test rig, such as the high-resolution heatable light scattering spectrometer Promo® 1000 H, the heatable dilution systems LDD 100 H, and the heatable aerosol generator PLG 2100, can be removed from the HMT 1000 and used for other applications, e.g., measurements directly on the engine.

The heart of the HMT 1000 is the light scattering spectrometer Promo^® 1000 H, which measures the particle size and the number of particles (and therefore the concentration) independently of each other but at the same time. With the aid of the Promo^® 1000 H, it is possible to perform very quick, precise, reproducible, and isothermal measurements.

Conventional quantitative gravimetric determinations are often not quick or sensitive enough and need more information about the particle size distribution. High-speed and volume-relevant oil separator testing are assured thanks to the excellent correlation between the quantitative distribution measurement and the gravimetric analysis. The clean gas concentration can be determined within 1 minute using the Promo^®1000 H system.

The viscosity of the oil – and therefore the particle sizes and particle concentrations in the oil mist – varies as a function of the engine temperature. For this reason, oil separators must be tested at different temperatures, i.e., with varying sizes of the particle (up to approx. 5-8 µm) and particle concentrations (approx. 10⁵to 10⁷particles/cm³) as well as different volume flows, to characterize them in terms of their capacity to separate. Changes to the separation properties of the separator, e.g., due to the change in volume flow, temperature, filter burden, etc., must be determined through a reliable online or in-situ measurement. To avoid condensation and evaporative effects, on the HMT 1000, the complete aerosol guide, including the preparation, sampling, and measurement volume, can be heated to 120°C. As a result, measurements of the isothermal fraction separation efficiency can be performed. Isothermal in-situ measurement, e.g., on the engine

The HMT 1000 test system is mobile and has a modular layout. As a result, the individual components can also be used for other tests and particle measurements, e.g., in-situ measurements on the engine.

The software has been tried and tested in practice and enables almost fully-automated characterization of oil mist separators. This means the results are independent of the person operating the test rig (see "Software" product group: FTControl).

Test rig control

• Automated control of the volume flow
• Automated activation process for the aerosol generator
• Automatic switching between raw gas / clean gas measurement point
• Automatic temperature regulation
• Evaluation and recording of measurement signals, e.g., Dp, rel. humidity, temperature, volume flow, absolute pressure, etc.

Automatic measurement process

• Automatic evaluation of the pressure loss curve
• Automatic measurement of the fraction separation efficiency
• Automatic evaluation of the pressure loss curve under varying burden states, incl. measurement of the fraction separation efficiency

Fig 1: Comparison of different oil separators