Isuzu E engine

The Isuzu E engine family started as a swirl chamber design, which was later modified into a direct injection design, the 4EE1, and finally improved into a 16-valve direct common rail injection engine, the 4EE2. Isuzu engines carry a two-character prefix which designates the number of cylinders and the engine family, so the 4 in 4EE1 and 4EE2 gives the cylinder count and E gives the family. The English Wikipedia list of Isuzu engines places the E engine among Isuzu's four-cylinder diesel engines, alongside the B, C, H and J families.