Diesel–electric powertrain

Diesel–electric transmission is used on railways by diesel–electric locomotives and diesel–electric multiple units, as electric motors are able to supply full torque from 0 RPM.

With auxiliary batteries the motors can run on electric alone, for example when the noise or exhaust from the engine disrupts a clean air zone.

[1] Disadvantages of a diesel electric transmission are the potential complexity, cost, and decreased efficiency due to energy conversion.

[citation needed] In World War II, the United States Navy built diesel–electric surface warships.

[5] Gas turbines are also used for electrical power generation and some ships use a combination: Queen Mary 2 has a set of diesel engines in the bottom of the ship plus two gas turbines mounted near the main funnel; all are used for generating electrical power, including those used to drive the propellers.

This provides a relatively simple way to use the high-speed, low-torque output of a turbine to drive a low-speed propeller, without the need for excessive reduction gearing.

While this solution comes with a few disadvantages compared to direct mechanical connection between the diesel engine and the propeller that was initially common, the advantages were eventually found to be more important.

One of several significant advantages is that it mechanically isolates the noisy engine compartment from the outer pressure hull and reduces the acoustic signature of the submarine when surfaced.

From that point onwards, diesel–electric transmission has been consistently used for all new classes of Swedish submarines, albeit supplemented by air-independent propulsion (AIP) as provided by Stirling engines beginning with HMS Näcken in 1988.

Examples include: In the automobile industry, diesel engines in combination with electric transmissions and battery power are being developed for future vehicle drive systems.

Partnership for a New Generation of Vehicles was a cooperative research program between the U.S. government and "The Big Three" automobile manufacturers (DaimlerChrysler, Ford and General Motors) that developed diesel hybrid cars.

The German armored vehicles VK 45.01 (P), Elefant, and Panzer VIII Maus of the Second World War were petrol-electric or diesel-electric propelled.

Future tanks may use diesel–electric drives to improve fuel efficiency while reducing the size, weight and noise of the power plant.