Dieselhydraulisch

Dieselhydraulisch, or diesel-hydraulic propulsion, refers to a drive system in which a diesel engine powers a hydraulic transmission that ultimately drives the wheels or propulsion shafts of a vehicle. In a typical setup, the diesel engine drives a hydraulic pump which pressurizes fluid. The fluid is processed by a torque converter or hydraulic coupling and transmitted to hydraulic motors or to a final drive that turns the axles. Power is transmitted through fluid rather than directly through electricity or a rigid mechanical link.

The core elements of a dieselhydraulic system include the diesel engine, a hydraulic pump, a torque converter or hydrostatic unit, and final drive components. This arrangement allows a compact, smooth transfer of power with strong low‑end torque, which is advantageous for certain mobile applications. In rail contexts, diesel-hydraulic locomotives and railcars used hydraulic torque converters to connect the engine to driving axles, avoiding traction generators used in diesel-electric designs.

Historically, diesel-hydraulic drive gained prominence in the mid‑20th century for both construction machinery and some European rail equipment. In railway use, it competed with diesel-electric propulsion; however, diesel-electric systems ultimately became more prevalent due to greater efficiency and easier scalability for high power. Today, dieselhydraulic transmissions are most common in construction and forestry machinery, cranes, and some specialized vehicles, where compactness and smooth control outweigh the efficiency advantages of electric transmission.

See also: diesel-electric propulsion, hydraulic transmission, torque converter, hydrostatic drive.