Automotive engine covers are very important components around the car's engine and are essential to keep driving safe.
Audi, Dongfeng, Geely engine cover selection Secret
For reasons of light weight and safety, the major automobile companies in the world have adopted the method of manufacturing automobile engine covers by plastic-forming steel, and have formulated the heat-resistance, long-term heat aging resistance and oil resistance of plastic materials The corresponding standard requirements. Such as Audi cars with high mobility nylon A1G6-HR enhanced, Dongfeng engine cover with long glass fiber reinforced PP material LGF-P1G6HM, Geely car engine cover with mineral enhanced PP material P1M8R-W01.
Therefore, through in-depth understanding of the market, different customers have different requirements for different application environments of the products. This requires careful analysis of the material performance requirements of the automobile engine cover and different requirements for material performance of different displacement vehicles , Engine cover selection is also different. At present, there are mainly three kinds of glass fiber reinforced PA, long glass fiber reinforced PP and mineral reinforced PP.
Table 1 different models of the program
First, PA + GF in the hood cover application
PA + GF is one of the best solutions for high-end automotive engine cover selection. PA + GF has excellent high temperature resistance, aging resistance and good mechanical properties, chemical stability, alcoholysis resistance and hydrolysis resistance, but poor fluidity, injection molding difficult. In order to increase its liquidity, it must be modified.
Such as: Audi cars used in high mobility A1G6-HR, with excellent flow and mechanical properties, increased mobility of nearly 60%, shorten the production cycle of 15% -30%, and the parts lightweight, thin-walled, and reduce the thickness of more Up to 20%.
Audi, Dongfeng, Geely engine cover selection Secret
Figure 1 Glass-reinforced nylon A1G6-HR for Audi engine covers
Engine hoods have a high requirement on the thermal aging mechanical properties of materials, and the materials used in engine hood covers must be related to the long-term thermal aging mechanical properties.
The thermal aging test of PA6-GF30 at 2500C for 2500 hours shows that the tensile strength retention of the PA6-GF30 is over 80% and the notched impact strength retention is over 65%, both of which have good Thermal aging properties. Therefore, PA-30GF material is suitable for the hood.
Second, the application of modified polypropylene in the hood
For auto parts manufacturers, the use of modified nylon means that higher molding temperatures and longer molding cycles are required to produce engine covers that meet the quality requirements. Therefore, it is a common demand in the industry to obtain a car engine cover material that has a more processing cost advantage.
Recently, long glass fiber reinforced PPmaterials are inexpensive and have the same superior performance as engineering plastics, thereby demonstrating the advantages of high cost performance. LFT-PP material refers to a modified PP composite containing glass fibers with a length of 10 to 25mm, which can effectively improve the rigidity, impact strength, creep resistance and dimensional stability of the product.
Audi, Dongfeng, Geely engine cover selection Secret
Figure 2 modified LFT-PP particles and cross-sectional view
Long Glass Fiber Reinforced Polypropylene Composites has the following characteristics:
Outstanding mechanical properties, excellent balance of rigidity and toughness;
Low shrinkage, very good stability over a wide temperature range and climatic conditions, high dimensional stability;
High notch impact strength;
The equivalent of metal thermal expansion coefficient;
Excellent resistance to dynamic fatigue
Under the same glass fiber content enhancement, the mechanical properties of Long Glass Fiber Reinforced Polypropylene Composites are similar to those of PA-GF materials, and its unique structure shows excellent mechanical properties. In addition, long glass fiber reinforced PP glass fiber reinforced PA6 products have the following advantages:
Table 2 Long Glass Fiber Reinforced Polypropylene Composites and glass fiber reinforced PA process comparison
PA6-GF30
Therefore, Long Glass Fiber Reinforced Polypropylene Composites instead of GF-PA used in engine cover products, with cost advantages and process advantages. For example, the current Dongfeng engine cover with LGF-P1G6HM this material, 30% long glass fiber reinforced polypropylene, high flow, high rigidity, high toughness, anti-aging.
Third, the modified mineral enhanced PP in a small displacement engine cover application prospects
Small displacement engine cover material performance requirements, compared to large displacement vehicles, the engine temperature around the lower, the material performance requirements are also reduced accordingly. This brings opportunities for the application of mineral reinforced PP materials. For this market segment, special mineral reinforced PP materials, such as P1M8R-W01, have a flexural modulus of 4000 MPa at room temperature and remain stable at high temperatures.
0.45MPa test conditions, the heat distortion temperature up to 126 ℃, with excellent heat resistance, in addition to meet the test requirements of the engine cover can significantly reduce costs. This material is a successful substitute for nylon and opens up a new market for mineral-enhanced PP-modified materials to enter the engine's peripheral applications and to replace engineering plastics.
Audi, Dongfeng, Geely engine cover selection Secret
Figure 3 Mineral enhanced PP P1M8R-W01 material used in Geely car hood
Fourth, the conclusion
Different customer's product positioning, the performance requirements of different materials. Therefore, the choice of PA + GF, or modified Long Glass Fiber Reinforced Polypropylene Composites or mineral enhanced PP, is based on the development needs of different enterprises. However, replacing some nylon with modified PP in some of the lower end cars is a good option to reduce costs.
Transferred from Albatron
