A drivetrain (also frequently spelled as drive train or sometimes drive-train ) or transmission system , is the group of components that deliver mechanical power from the prime mover to the driven components. In automotive engineering , the drivetrain is the components of a motor vehicle that deliver power to the drive wheels . This excludes the engine or motor that generates the power. In marine applications, the drive shaft will drive a propeller , thruster, or waterjet rather than a drive axle , while the actual engine might be similar to an automotive engine. Other machinery, equipment and vehicles may also use a drivetrain to deliver power from the engine(s) to the driven components.
19-461: In contrast, the powertrain is considered to include both the engine and/or motor(s) as well as the drivetrain. The function of the drivetrain is to couple the engine that produces the power to the driving wheels that use this mechanical power to rotate the axle. This connection involves physically linking the two components, which may be at opposite ends of the vehicle and so requiring a long propeller shaft or drive shaft . The operating speed of
38-414: A motor vehicle , the powertrain consists of the source of propulsion (e.g. the engine or electric motor) and the drivetrain system which transfers this energy into forward movement of the vehicle. The powertrain consists of the prime mover (e.g. an internal combustion engine and/or one or more traction motors) and the drivetrain - all of the components that convert the prime mover's power into movement of
57-444: A hybrid vehicle includes a charging socket, it is considered to be a plug-in hybrid , while vehicles that do not include a charging socket (therefore relying on the engine or regenerative braking to charge the batteries) are considered to be mild hybrids . Powertrain In a motor vehicle , the powertrain comprises the main components that generate power and deliver that power to
76-551: A wider sense, the powertrain includes all of the components used to transform stored (chemical, solar, nuclear, kinetic, potential, etc.) energy into kinetic energy for propulsion purposes. This includes the utilization of multiple power-sources and non–wheel-based vehicles. The most recent developments in powertrain are driven by the electrification of it in multiple components. Electrical energy needs to be provided, usually this leads to larger batteries. Electric motors can be found as isolated component or as part of other elements, e.g.
95-595: Is achieved through metrology technology applied to all of the steps in powertrain manufacturing processes. In automotive manufacturing, the frame plus the "running gear" makes the chassis . Later, a body (sometimes referred to as " coachwork "), which is usually not necessary for integrity of the structure, is built on the chassis to complete the vehicle . Commercial vehicle manufacturers may have "chassis only" and "cowl and chassis" versions that can be outfitted with specialized bodies. These include buses , motor homes , fire engines , ambulances , etc. The frame plus
114-733: Is important to industry, including the automotive and other vehicle sectors. Competitiveness drives companies to engineer and produce powertrain systems that over time are more economical to manufacture, higher in product quality and reliability, higher in performance, more fuel efficient, less polluting, and longer in life expectancy. In turn these requirements have led to designs involving higher internal pressures, greater instantaneous forces, and increased complexity of design and mechanical operation. The resulting designs in turn impose significantly more severe requirements on parts shape and dimension; and material surface flatness , waviness , roughness , and porosity . Quality control over these parameters
133-404: Is the diesel engine that is mechanically coupled to the driving wheels (drivers). In a diesel-hydraulic locomotive , the prime mover is the diesel engine that powers the pumps of one or more torque converters mechanically coupled to the drivers. In a diesel-electric locomotive , the prime mover is the diesel engine that rotates the main generator responsible for producing electricity to power
152-561: Is the last in the set of components which delivers torque to the drive wheels . In a road vehicle, it incorporates the differential . In a railway vehicle, it sometimes incorporates the reversing gear. Examples include the Self-Changing Gears RF 28 (used in many first-generation diesel multiple units of British Railways ) and RF 11 used in the British Rail Class 03 and British Rail Class 04 diesel shunting locomotives. In
171-574: The British Rail Class 03 and British Rail Class 04 diesel shunting locomotives. This section uses infographics to show a unified model with variations, the green wheels denote no traction, and the angled wheels denote steering. 6X4 means 6 wheel ends and 4 positions distribute power (power divider installed) 6X2 means 6 wheel ends and 2 positions distribute power (single axle drive) 4X0 means 4 wheel ends no power (Trailer axle) 4x2 means 4 Wheel ends, 2 Positions to distribute power The 6 wheel ends can either be wide base singles or duals. Its about
190-492: The axle . In hybrid powertrains the torque generated by the combustion engine and the electric motor have to be brought together and distributed to the wheels. The control of this process can be quite involved but the rewards are greatly improved acceleration and much lower emissions. Powertrain development for diesel engines involves the following: exhaust gas recirculation (EGR), and advanced combustion. Spark ignition engine development include: fuel injection , including
209-642: The gasoline direct injection variant, as well as improving volumetric efficiency by using multi-valves per cylinder, variable valve timing , variable length intake manifolds , and turbocharging . Changes also include new fuel qualities (no sulphur or aromates ) to allow new combustion concepts. So-called "combined combustion systems" (CCV) or "diesotto" cycles are based on synthetic fuels (synthetic diesel, biomass to liquid (BTL) or gas to liquid (GTL)). BEVs , FCEVs and PHEV powertrains are expected to reach cost parity with ICE powertrains in 2025. The manufacturing of powertrain components and systems
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#1732877077162228-445: The traction motors that are geared to the drivers. The prime mover can also be a gas turbine instead of a diesel engine. In either case, the generator, traction motors and interconnecting apparatus are considered to be the power transmission system and not part of the prime mover. A wired-electric or battery-electric locomotive has no on-board prime mover, instead relying on an external power station . The power unit represents
247-428: The body makes a glider (a vehicle without a powertrain). The final drive is the last in the set of components which delivers torque to the drive wheels . In a road vehicle, it incorporates the differential . In a railway vehicle, it sometimes incorporates the reversing gear. Examples include the Self-Changing Gears RF 28 (used in many first-generation diesel multiple units of British Railways ) and RF 11 used in
266-449: The engine and wheels are also different and must be matched by the correct gear ratio . As the vehicle speed changes, the ideal engine speed must remain approximately constant for efficient operation and so this gearbox ratio must also be changed, either manually, automatically or by an automatic continuous variation . The precise components of the drivetrain vary, according to the type of vehicle. Some typical examples: The final drive
285-449: The main weight in a locomotive design, other than the chassis or body. Its position back and forth is at the designer's choice and may be used to control overall weight distribution. In most locomotives designs, the power unit is placed centrally. In some locomotives, it is offset to one end, or the heavier engine is outboard of the generator. In extreme cases, such as C-B wheel arrangements , the weight on each bogie may differ so much that
304-408: The outside of the wheels. Prime mover (locomotive) In engineering, a prime mover is an engine that converts chemical energy of a fuel into useful work . In a locomotive , the prime mover is thus the source of power for its propulsion . In an engine-generator set , the engine is the prime mover, as distinct from the generator. In a diesel-mechanical locomotive, the prime mover
323-479: The road surface, water, or air. This includes the engine , transmission , drive shafts , differentials , and the final drive ( drive wheels , continuous track as in military tanks or caterpillar tractors, propeller , etc.). Hybrid powertrains also include one or more electric traction motors that operate to drive the vehicle wheels. All-electric vehicles ("electric cars") eliminate the engine altogether, relying solely on electric motors for propulsion. Occasionally
342-422: The term powerplant is casually used to refer to the engine or, less often, the entire powertrain. A motor vehicle's driveline or drivetrain consists of the parts of the powertrain excluding the engine. It is the portion of a vehicle, after the prime mover , that changes depending on whether a vehicle is front-wheel , rear-wheel , or four-wheel drive , or less-common six-wheel or eight-wheel drive . In
361-638: The vehicle (e.g. the transmission , driveshafts , differential and axles ); whereas the drivetrain does not include the power source and consists of the transmission, driveshafts, differential and axles. Most passenger cars and commercial vehicles are powered by either an internal combustion engine , electric motor (s) or a combination of the two. The most common types of internal combustion engines are: Most purely electric vehicles use batteries for energy storage and are referred to as battery electric vehicles . Vehicles with both internal combustion engines and electric motors are called hybrid vehicles . If
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