Good welding characteristics, low warpage and excellent flow characteristics were decisive factors in choosing reinforced polyamide for diesel engine oil separators.

System supplier Bosch Waiblingen Kunststofftechnik, in collaboration with Rhodia Engineering Plastics' Application Development Centre Automotive in Freiburg, has developed housings and other elements manufactured using Technyl reinforced polyamide for two new oil separator concepts for diesel engines. DaimlerChrysler is currently considering using the stand-alone solution of this oil separator with three hose connections for its A-Class diesel models. Series production for other diesel applications, using a cassette version fitted to the aluminium rocker cover, will start in the near future.

The material which will be used for both models is Technyl A 218 MT15 V25, a heat stabilised, glass and mineral reinforced polyamide 66.

It has been selected because it meets the stringent demands placed on its mechanical properties, durability and processing.

In the environmentally-friendly closed crankcase ventilation system, when the engine is running, the blow-by gas finds its way from the combustion chambers into the crankcase.

It then flows through the oil separator.

The gas is an aggressive combination of air, fuel remnants such as water vapour, soot and other combustion by-products, as well as oil mist and oil droplets.

The separator splits out almost all the oil and other fluid particles which are reintroduced into the oil system, while the remaining gas is fed back into the air intake.

The oil separator housing, the coil for the centrifugal oil separator for the larger drops and the support for the fleece which absorbs the fine oil mist, are all made from Technyl A 218 MT15 V25.

The support for the pressure control valve membrane is made of fluorine silicon-coated polyamide.

'We believe that this new type of oil separator will open up a wide range of new market opportunities.

The concept is a real step forward and we feel confident it will be the forerunner of a whole new generation of oil separators', said Eric Noyrez, Director Automotive Business, Rhodia Engineering Plastics.

The combination of glass and mineral particles in this Technyl grade precisely provides the demanding mix of properties required in this application, as well as meeting the demand of high production efficiency.

The hostile environment in which the oil separators are used means that they need to have outstanding rigidity and dimensional stability, high creep resistance and be able to withstand temperatures from -35degC to 130degC.

They also have to resist ageing when exposed to an aggressive mixture of lubricating oil, fuel, water and acids, and external factors such as road salt.

Good welding characteristics, low warpage (which simplifies machine tool construction) and Technyl's excellent flow characteristics were decisive factors in Bosch's decision to use the material.

According to Axel Zschau, Leader Application Development Centre Automotive at Rhodia Engineering Plastics, 'This new development is a result of a high level of co-operation between our two companies.

The challenge was to find a way to combine different oil separation systems in the small space available.

We managed to achieve the maximum system efficiency we were both looking for.

This project is one example of the way in which we work with our customers to help them to develop solutions that, as in this case, are often revolutionary.' Rhodia Engineering Plastics assisted Bosch during the material selection and its optimisation of the manufacturing process.

Rhodia offers its customers a wide range of support services during the commercialisation of their projects, such as flow simulation and finite element simulations, as well as a variety of laboratory tests like ageing, burst pressure and leakage tests.

Rhodia Engineering Plastics, headquartered in Lyon, France, is the worldwide specialist in polyamide engineering thermoplastic materials.

The company has a sales network that spans the world, with manufacturing plants and technical development centres in Europe, North America, South America and Asia.

Rhodia is one of the world's leading manufacturers of speciality chemicals.

Providing a wide range of innovative products and services to the consumer care, food, industrial care, pharmaceuticals, agrochemicals, automotive, electronics and fibres markets, Rhodia offers its customers tailor-made solutions based on the cross-fertilisation of technologies, people and expertise.

Rhodia subscribes to the principles of Sustainable Development communicating its commitments and performance openly with stakeholders.