Increasing automotive usage drives exploration of polymer matrix composite (PMC) materials rather than conventional metals, such as aluminum (Al), for engine pistons and valve plates, to reduce mass and fuel consumption. The PMC materials generally offer many advantages
but have poor thermal properties. Since poly(ether ether ketone) (PEEK) offers superior mechanical properties and thermal stability among thermoplastics, it can be used as a matrix in combination with conventional Al. However, the PEEK-Al composite has not been studied yet, either by simulation or experiment, for these engine parts. In the present study, a novel PEEK-Al composite system was designed, with Al content varying from 10–40 vol%, to identify the composition that yields the optimal mechanical and thermal properties. A structural and thermal analysis was performed using finite element analysis (FEA) in ANSYS. The present results were compared to determine the optimal composite compositions based on their thermomechanical properties. From the entire present FEA results, it is concluded that the PEEK-40%Al has best overall optimum mechanical (i.e., up to 1.056×107 Pa shear stress for Plate and 8.815×107 Pa shear stress for piston) and heat transfer (i.e., up to 2590.3 W/m2 heat flux for Plate and 74.939 W/m2 for Piston) characteristics for plate and piston materials. Hence, PEEK-40%Al, which has the
best heat-transfer characteristics, can be applied to both engine plates and piston components. Hence, these PEEK-Al composites will enhance engine efficiency and align with automotive sustainability goals.