A study of factors affecting plastics intake manifold strength against backfire phenomena

Proper and uniform charge distribution in engine cylinders is the main function of intake manifold. Generally, this piece is made of aluminum or plastic. Plastic manifold, in comparison to aluminum manifold, have better weight and lower cost of production, better thermal insulation and improved volumetric efficiency, but due to the poor strength of plastic manifolds against the destructive effects of backfire phenomena compared to aluminum manifolds, corrective measures to improve and validate the strength of the part against this phenomenon must be undertaken. Due to the fact that testing the strength of the piece against this phenomenon is always associated with difficulty; in this paper all parameters which affect the strength of plastic intake manifolds by applying the proposed test procedure are discussed. At first, via the proposed validation test, the effect of raw material and glass fiber percent are investigated and in the following, after simulating with ABAQUS software and validating it with the experimental results, the effect of glass fiber and the layer thickness on the concentration of the plastic manifold stress of the national engine has been investigated; considering the proposed procedure. The results of validation tests and simulation show that, thickness, glass fiber content and the quality of raw material are the main parameters that improve the strength of the plastic manifold respectively.