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Description / Abstract:
This standard covers the material requirements of engine tubes
that are exposed to exhaust gas condensate and positive crankcase
and ventilation, also known as vent and blow-by hoses, for use in
automotive systems. Material properties are suitable for low vacuum
and pressure tubes not requiring reinforcement, but reinforced
hoses can as well be used and are part of this specification.
Material properties are also suitable for vacuum hoses. No
resistance tests to crank-case ventilation gases per GMW17227 are
required for vacuum hoses.
Material Description. Materials covered by this
specification are divided into several Types and Classes, depending
on construction and temperature capability. See Table 1. Hoses are
defined by the Construction and Temperature capability.
Hoses are either suitable for applications subjected to maximum
continuous operation temperatures of +150 °C with intermittent
operation at temperatures up to +175 °C maximum, to maximum
continuous operation temperatures of +175 °C with intermittent
operation at temperatures up to +200 °C maximum, or for
applications subjected to maximum continuous operation temperatures
of +200 °C with intermittent operation at temperatures up to +225
°C, dependent on the Temperature Rating of the hose. The
designation for the blow-by hose is defined as GMW17391 Type VWYZ,
where V defines the construction of the hose, W defines the
temperature capability of the hose, Y defines reinforcement, and Z
defines the requirements for GMW17227 qualifications.
- Suffix Code Z for requiring GMMW17227 is xxxx1; if no
resistance is needed, xxx2.
- If no suffix is given, suffix A shall apply.
- Detailed overview of all types are shown in Table 1.
Note: Continuous and Excursion temperature
limits are defined in the Vehicle Technical Specifications (VTS).
The cold resistance test for all types of hoses is defined at -30
°C, however, hoses will be able to operate at -40 °C as soon as
they are immersed with oil and blow-by in the engine.
Symbols. Not applicable.
Applicability. For all elastomeric tubes and
hoses exposed to Positive Crankcase Ventilation (PCV), Exhaust Gas
Recirculation (EGR) gases, and vacuum tubes/hoses.