Comparison of the surface morphologies of ceramic reinforced metal matrix composite cams after wear tests under dry and wet conditions

Abstract

The integral engine parts, such as camshaft members, are usually not preferably made of ceramic-reinforced MMC because the margin of compromise on the engine performance is small. However, the lightweight and wear-resistant nature of the mentioned materials can benefit fuel consumption without necessarily compromising engine performance. In this study, Al (AA2124) matrix is reinforced with ceramic particles of two different types (SiC, B4C), size distributions (B4C: 1–7, SiC: 2 and 20 μm), and volume fractions (0, 10, 20, 30 vol.%) to manufacture camshaft cams (lobes). While MMC cams are manufactured by powder metallurgy (300 MPa, 615°C, 30 minutes), spherical graphite cast iron (GGG40) cams are prepared by casting, induction hardening, and machining. The wear behavior of MMC cams is compared with the reference unreinforced AA2124 and conventionally used cast iron cams under dry and virtually created engine-like wet conditions. It was attempted to correlate the percentage increase in the roughness and weight loss with the structure of the cams using SEM, EDX, and macroscopy analysis. Results showed that the initiation of a three-body abrasive wear mechanism for 30 vol.% of the larger SiC particles caused lower wear resistance in the cams under dry conditions. As for the wet conditions, although the cams’ wear resistance increased with increasing ceramic particles’ content, it resulted in enhanced wear in the counterface when larger ceramic particles were used as reinforcement. Overall, higher ceramic content and larger particle size encourage three-body abrasive wear between the interacting surfaces and assist in degraded wear resistance under wet conditions.

Cam Profile Design of Low-Speed Marine Diesel Engine Based on the Grey Theory

“…The cam profile design, which is at the center of the gas distribution mechanism, plays a crucial role in the internal combustion engine's ability to exchange gases. The benefits and drawbacks of this design directly affect the engine's fuel efficiency, stability, and reliability as well as its ability to vibrate, produce noise, and perform an efficient intake sweep [1,2]. The ongoing enhancement of the engine strengthening index necessitates that the valve lift curve exhibits swift opening and closing actions in order to achieve a substantial fullness coefficient in the valve lift section.…”

“…1,14, 12, and 6. The best combinations of C4, p, n, and m parameters achieved with jerk as the response target are 0.3, 10, 10, and 4.…”

Ceramic Particle Reinforced Camshaft Lobes: A Performance Evaluation and Comparative Analysis

“…The feasibility of using the Al matrix ceramic reinforced cams as a replacement to conventionally used high alloy steels [2][3][4] was investigated in the previous study [5]. However, results showed that the behavior of the cams was influenced not only by the types and ratios of the ceramic (B4C or SiC) particles, but also by the size of the reinforcement particles.…”

“…However, results showed that the behavior of the cams was influenced not only by the types and ratios of the ceramic (B4C or SiC) particles, but also by the size of the reinforcement particles. However, since the mentioned study [5] was intended to develop a virtual engine-like wear environment and conduct the feasibility analysis of the ceramic reinforced Al matrix composite as cams, influence of longer durations of the wear tests was not reported. But for a proper representation of said composites to be claimed as a replacement to conventional steels cams, performance evaluation is inevitable.…”

“…In order to solve this problem, a much-automated system with minimum performance degradation must be prepared. The working principles and the component details of the setup are already detailed in the previous study [5]. The setup mimics the real-life engine conditions based on the principles of the valve train system (actuation of engine valves using lobes on the camshaft) in dry and wet conditions.…”