HW4Z series high efficiency environmental protection marine shaft generator is driven by main engine, and makes full use of main engine's residual power. When running under the low efficiency of less than 75%~85% rated power, main engine will run a long time in the high load, which can effectively reduce the consumption of fuel, cut shipping cost and reduce emission. At the same time, when it adopts shaft generator, and usually reduces one set of auxiliary generator set, which saves engine and ship space, and improves the quality of environment, reduce noise in the ship equipment installation cabin。