Ford Keeps It Cool

Walworth, WI and Woodlands, TX - As Ford's engineering designs heated up for its new flagship sedan, the company and its suppliers found a way to keep things cool. In an effort to maximize space in the engine compartment, Ford utilized a new design for the Ford Five Hundred's cooling system. Driven off one of the overhead camshafts, the new direct drive water pump reduces part count by integrating the sedan's thermostat housing. This modification also reduces noise, vibration and harshness.

During the Five Hundred's developmental stage, Ford paired with Miniature Precision Components, Inc. (MPC), an automotive equipment manufacturer of molded and extruded thermoplastic components, to design and engineer the thermostat housing for the new water pump. The proposed design required a plastic part with nine sealing joints to integrate the thermostat housing and water pump, which in turn would allow the part to fit in the small packaging space. The part needed to withstand great load force during the assembly line's coolant fill, and prohibit any corrosion as a result of the long-life, chemically aggressive coolant itself.

With these tough design challenges in mind, MPC began researching thermoplastic materials. Chevron Phillips Chemical Company LP's (Chevron Phillips Chemical) Ryton Polyphenylene Sulfide (PPS) provided the properties necessary to complete the task. Ryton PPS' minimal moisture absorption and low coefficient of linear thermal expansion also made the material an ideal fit for molding to the complex part's tight tolerances. MPC chose to mold a prototype using Ryton PPS R-4-220BL, taking advantage of this grade's hydrolysis resistant properties.

Using Finite Element Analysis, the molded part underwent rigorous structure and stress analysis, several design iterations and mold-filling simulation. Low creep resistance was achieved by conducting a series of strain vs. time curve tests, applying a constant tensile load at constant temperature. Additionally, Ryton PPS' durability enabled the part to withstand a grueling three million cycle fatigue test at 90 psi and 240 F. Ultimately, the part was approved by MPC's Design Validation Plant and integrated into an assembly simulation.

Overcoming space and durability challenges, the teams at Ford, MPC and Chevron Phillips Chemical found a cool thermoplastic solution for a hot innovative design. Today, Ford's Chicago Plant integrates a MPC molded, Ryton PPS direct drive water pump into every Ford Five Hundred that rolls off the assembly line.

SOURCE: MPC