BASF’s Ultramid PA used for production of charge-air duct on truck engines
BASF announced that its new polyamide (PA) grade Ultramid A3W2G6 was used by the first time for large production of the charge-air duct on the DD13/DD15 truck engines.
The component, produced by Germany original equipment manufacturer (OEM) ElringKlinger from the very heat aging-resistant PA, is said to offer high mechanical and thermal strength. The multifunctional oil intake module is also manufactured from a BASF polyamide. The designation DD13/DD15 covers a range of high-performance truck diesel engines with a displacement of about 13L and 15L, respectively, that Detroit Diesel Corporation, truck engine and component manufacturer and Daimler subsidiary, builds in the US.
Compared to its aluminum predecessor, the lightweight charge-air duct made from the BASF PA is 1.8 kg, or 50 %, lighter, according to the Germany-based material supplier. The high heat-aging resistance of the PA 66 specialty Ultramid A3W2G6 component has been put in pulsating pressure tests at 140°C. The charge-air duct must survive 3,000 hours of pressure fluctuations between 0.4-3.5bar. These are special requirements in the commercial vehicle sector, arose from the mixing of turbocharged fresh air with up to 230°C of exhaust gas recirculation (EGR). At the point where the exhaust gas is reintroduced and under high loads, as when climbing steep grades to mountain passes, peak temperatures of up to 200°C can occur.
The oil intake module on the DD13/DD15 is also made from Ultramid A3WG7 and, in addition to the oil intake connection and oil supply line, incorporates an integrated check valve. In the component test, the aged material has to withstand over 10 million oil pressure pulsation cycles between 5-13bar at 120°C.
In long-term testing of the check vale, 500,000 cycles must be withstood in the presence of a sharp oil mixture that contains not only aged engine oil but also fuel components. Ultimately, a truck is expected to drive about 1.2 million km. In this part, BASF says substitution of Ultramid for metal and the high degree of functional integration resulted in cost and weight reductions of 0.8kg, or 50 % per part.
With the aid of its universal computer simulation instrument Ultrasim, BASF provided assistance to the development staff at ElringKlinger. In the case of the oil module, one of the objectives was to prevent material fatigue induced by dynamic engine operation and in this way maximize the service life.
At the same time, the weld seams had to be designed very carefully because they are potential weak spots that should be subjected to the lowest possible load during operation. Computational design techniques were used to satisfy both requirements, in the first case, numeric topology optimization; in the second, shape optimization.
By employing bionic principles, BASF notes the virtual approach places plastic at precisely the locations of the component where it is really needed and must withstand loads. This development was accompanied by leak, pulsating pressure and burst pressure tests in the component testing laboratory at BASF.