The Type segment of the Truck Diesel Engine market is organized around core architectural and performance characteristics. Inline (direct‑injection) engines dominate due to their balance of efficiency and manufacturing simplicity, accounting for roughly 40 % of total unit shipments. V‑type configurations are favored in high‑power applications, especially in heavy‑duty trucks, where their compact footprint and ability to deliver >500 hp contribute about 25 % of market volume. Turbocharged engines enhance power density and fuel economy across all classes, representing close to 20 % of the market, while aftercooled (intercooled) units provide additional thermal management for emissions compliance, adding another 10 %. Finally, emerging electrified‑assist diesel hybrids occupy a nascent 5 % share, reflecting early adoption in regions with stringent CO₂ targets. Each subtype’s share directly influences overall market size by dictating production tooling, parts inventory, and R&D allocation, thereby shaping the revenue distribution within the broader Truck Diesel Engine sector.