Propulsion system in the context of Automotive engine

Marine propulsion is the mechanism or system used to generate thrust to move a watercraft through water. While paddles and sails are still used on some smaller boats, most modern ships are propelled by mechanical systems consisting of an electric motor or internal combustion engine driving a propeller, or less frequently, in pump-jets, an impeller. Marine engineering is the discipline concerned with the engineering design process of marine propulsion systems.

Human-powered paddles and oars, and later, sails were the first forms of marine propulsion. Rowed galleys, some equipped with sail, played an important early role in early human seafaring and warfare. The first advanced mechanical means of marine propulsion was the marine steam engine, introduced in the early 19th century. During the 20th century it was replaced by two-stroke or four-stroke diesel engines, outboard motors, and gas turbine engines on faster ships. Marine nuclear reactors, which appeared in the 1950s, produce steam to propel warships and icebreakers; commercial application, attempted late that decade, failed to catch on. Electric motors using battery packs have been used for propulsion on submarines and electric boats and have been proposed for energy-efficient propulsion.

An underwater vehicle is any member of the class of watercraft that is intended to operate in the underwater environment, as opposed to surface vessels that only stay afloat on top of water. This article lists the types of underwater vehicle, with a brief description of each type. An underwater vehicle can be crewed or unmanned (which may be remotely operated or fully autonomous), and will generally, but not necessarily, have some form of onboard propulsion system.

There are a wide variety of propulsion systems available or potentially available for automobiles and other vehicles. Options included internal combustion engines fueled by petrol, diesel, propane, or natural gas; hybrid vehicles, plug-in hybrids, fuel cell vehicles fueled by hydrogen and all electric cars. Fueled vehicles seem to have the advantage due to the limited range and high cost of batteries. Some options required construction of a network of fueling or charging stations. With no compelling advantage for any particular option, car makers pursued parallel development tracks using a variety of options. Reducing the weight of vehicles was one strategy being employed.

SZ DJI Technology Co., Ltd. or Shenzhen Da-Jiang Innovations Sciences and Technologies Ltd. (Chinese: 深圳市大疆创新科技有限公司; pinyin: Shēnzhèn Shì Dà Jiāng Chuàngxīn Kējì Yǒuxiàn Gōngsī) or DJI (大疆创新; Dà Jiāng Chuàngxīn), is a Chinese technology company headquartered in Shenzhen, Guangdong. DJI manufactures commercial unmanned aerial vehicles (drones) for aerial photography and videography. It also designs and manufactures camera systems, gimbal stabilizers, propulsion systems, enterprise software, aerial agriculture equipment, and flight control systems.

DJI accounted for over 90% of the world's consumer drone market as of June 2024. Its camera drone technology is widely used in the music, television, and film industries. The company's products have also been used by military and police forces, as well as terrorist groups, with the company taking steps to limit access to the latter.