PBT plastics allows a user to mould an airflow sensor body in one piece without annealing - saving two production steps, when compared to alternative materials.

Hitachi Automotive Systems Europe has selected a reinforced Arnite polybutylene terephthalate (PBT) blend from DSM Engineering Plastics for injection moulded mass airflow sensor body destined for Audi engines. Arnite TV4 261 30% glass reinforced grade PBT provides a combination of properties important to the application, including excellent flow, long term dimensional stability, stiffness and strength over a wide temperature range and chemical resistance. Production requires only moulding - no annealing is required to relieve internal stresses that could lead to warpage.

'Throughput is excellent with this design,' said Andrew Bridge, procurement and design manager for Hitachi.

'The ability to mould the unit in one piece without annealing saves us two production steps compared to less sophisticated, two-piece approaches with alternative materials.' The Hitachi body serves both to mount the mass airflow sensor system precisely and to shape air flow using a moulded-in grid.

To control the turbulent airflow, the grid induces a laminar flow that helps ensure accurate feedback about engine air intake temperature to the engine control unit.

Mass airflow sensor data help engine control systems maintain an optimum air-fuel balance.

The grid's thin-wall elements and intricate geometry benefit from Arnite's flow properties, minimising moulded-in stresses and strains that later might contribute to warpage or unpredictable dimensional change, causing the sensor to misread airflow.

The design process for the component was a collaboration involving Hitachi, moulder and toolmaker WH Smith and Sons, materials and processing expert DSM Engineering Plastics and design and mold flow specialist DSM/DADC (Design and Development Centre).

* About Hitachi Europe - Hitachi Europe Limited is a wholly owned subsidiary of Hitachi Limited, Japan.

Headquartered in Maidenhead, UK, it has operations in 15 countries and employs 470 people across Europe, the Middle East and Africa.

As a 'Best Solutions Partner' Hitachi Europe tailors its services and solutions to meet the specific needs of its customers.

Hitachi Europe comprises eleven key business areas: power and industrial systems; rail; industrial components and equipment; information systems; high performance computing; digital media; display products; air-conditioning and refrigeration systems; procurement and sourcing; corporate technology group (research and development) and the Hitachi Design Centre.

Hitachi Automotive Systems Europe is headquartered in Horwich, Bolton UK.

* About DSM Engineering Plastics - DSM Engineering Plastics is a business group forming part of DSM's Performance Materials cluster.

DSM Engineering Plastics is a global supplier of Stanyl PA46 and Akulon 6 and 66 polyamides, Arnitel TPE-E, Arnite PBT and PET polyesters, Xantar polycarbonate, Yparex extrudable adhesive resins, and Stamylan UH Ultra High Molecular Weight PE.

These materials are used in technical components for electrical appliances, electronic equipment and cars, in barrier packaging films as well as in many mechanical and extrusion applications.