Diesel engines are known for their excellent low-end torque, better drivability, performance, and better fuel economy. The increase in customer demands pushes to deliver higher power and torque along with fuel economy. This requirement puts a great challenge on the overall weight of the engine. This paper explains the holistic approach followed along with optimizing the rocker arm cover to achieve the weight target without compromising on durability and cost in the commercial segment 2.5-liter Diesel Engine.
This paper presents a complete overview of the design and development of Rocker Arm (RA) cover to meet Strength, Durability, NVH and Aesthetic in Commercial Engine where base design is in aluminum which is mounted on cylinder head with a separate breather system. From aluminum the base design of Rocker arm cover is optimized to sheet metal where in there is reduction of 43% in weight and cost saving of 13%. The proposed design is optimized to meet the durability, NVH and without compromising on functional aspects for mounting the separate breather system.
Further it was optimized such that separate breather system is integrated with rocker arm cover and the base cover is converted to plastic. As the cover is converted to plastic and the internal components of breather system (Fleece, Baffles, PRV, etc.) which aid in oil separation can be welded onto the base plastic. This reduces the assembly cost, no of bolts, cycle time. Optimized plastic RA Cover reduced the weight by 34% against sheet metal proposal along with separate breather system and 53% against aluminum metal proposal along with separate breather system. In addition, there is cost saving of approx. 40% against sheet metal proposal and 46% against aluminum proposal. Both the sheet metal and plastic proposals are optimized to meet the desired functional targets like oil separation, blow by efficiency and durability targets without any failure in simulation, vehicle durability and final proposal is good aesthetic as it is in plastic.