New use of polyamide 6 helps cuts weight of engine oil pan

Specialty plastics company Lanxess has announced the development and use of polyamide 6 for an engine oil pan.

The trend of manufacturing engine oil pans from plastic instead of metals such as aluminium is continuing to gain ground. For historical reasons, the plastic of choice to date has almost always been polyamide 6.6, says Lanxess. However, newer designs are favoring polyamide 6, an alternative that offers a similarly high-quality property profile, but is much more economical.

The latest design of this type is the oil pan module for the new six-cylinder Boxer engines of the Porsche 911 Carrera, which is being manufactured using Durethan from Lanxess. “The component fully satisfies the specific requirements for functional integration, lightweight construction and cost-effective production that the new generation of engines has to meet,” says Jorge Soares, project manager for the highly complex component at Polytec Plastics Germany GmbH & Co KG, which is based in Lohne. The oil pan module has been developed in close collaboration between Polytec and Porsche. 

Importantly, polyamide 6 has helped to reduce the weight of the upper and lower sections of the oil pan to 1.3 and 1.8 kilograms respectively. Overall, the oil pan is more than two kilograms lighter than its aluminium predecessor, due to the lower density of the plastic and the optimized wall thicknesses. 

Tests confirm suitability
In a study carried out for Porsche, Lanxess says it proved the feasibility of manufacturing motor oil pans from polyamide 6. For example, aging tests were carried out to determine the durability of the thermoplastic under exposure to elements such as new and used engine oil. Specimen storage tests spanning a total of 3,000 hours at 150deg C were performed on highly reinforced, hydrolysis-stabilized, easy-flowing and high-temperature-stabilised Durethan grades, among others.

“The test results show that the aging behavior of heat-stabilized polyamide 6 is only marginally different to that of heat-stabilized polyamide 6.6 in terms of tensile strength, Young's modulus, elongation at break and impact strength. Appropriately optimized polyamide 6 compounds are therefore ideally suited for use in components that convey engine oil,” says Christof Boden, expert for engine compartment applications from Lanxess.

The specialty chemicals company is making the test results – and other material data – available to development partners as part of joint projects. Furthermore, customers are supported through every stage in the development of an oil pan as part of the HiAnt customer services package. This brand incorporates HPM's extensive material, simulation and processing competence, which it offers to customers through all stages of component development. Services include, for example, simulating mould filling including warpage calculation, simulation of stone impact and sealing forces, or testing of components with regard to sealing gap expansion and stone impact. 

Injection moulding process with benefits
A key argument in favour of manufacturing the oil pan using injection moulding was the huge potential that the process offers for integrating functions and thereby cutting costs. It also helps that since the parts are produced in a single step in the mould, there is no need for complex finishing work such as deburring die-cast aluminum parts. The lower energy costs are another benefit in favour of manufacturing injection-moulded parts.