Diesel locomotive
A Diesel locomotive is a locomotive of the railroad, which draws its operating power from one or more built diesel engines.
History of diesel locomotives
Diesel locomotives were developed in the course of history only after the steam and electric locomotives. The big problem of the first experiments with diesel engines for railway traction was the need to start the engine without load and generate a positive connection to the drive wheels and the rail after running up the engine.
After initial trials ( trials, as with friction clutches to drive the truck) and singular concepts (diesel Druckluftlok with rod drive such as the Diesel - Sulzer - Klose- thermal engine ) turned first to the diesel-electric propulsion as a viable solution out at the the diesel engine drives a generator, and the stream is switched on the electric wheel drive motors. For the first time this concept of Yuri Vladimirovich Lomonosov was used for a large range locomotive of the employed in the Soviet Union in 1924 diesel locomotive Ээл2. The concept has proven to today proliferation; large parts of the freight train traction in North America as well as the Soviet Union based thereon. Per import reached the 6-axle large diesel locomotives from the Soviet Union in the DDR ( 130/131/132/142 BR and BR 120).
In Central Europe, especially in Germany, the diesel locomotive was able to prevail mainly after the Second World War with the hydraulic power transmission. This is based on the Föttinger clutch and the concept of the torque converter as well as the manufacturing technology developments from companies like Voith. It also single six-axle diesel locomotives were up to 120 t weight built as development patterns ( a V 320, a BR 240, 300 V for JŽ ), but continued the German Federal Railroad more on four-axle locomotives with up to 80 tonnes in weight. The reason was the lack of demand due to the great benefits Electrification of the main routes.
Today's state of the art diesel-electric locomotives for freight with more than 4400 kW propulsion power; Multiple units with turbo electric power heads are now reaching cruising speeds of 240 km / h with a continuous output of the traction motors of 3300 kW per engine head.
In passenger diesel locomotives will be more and more replaced by diesel-powered railcars in Germany for several years, only the transport of heavy express trains is predominantly still performed with locomotives.
Advantages and Disadvantages
The advantages of the diesel locomotive is one, before that it requires no expensive overhead line in contrast to the electric locomotive and the other part, and after the ride does not have to be so complicated waited in the depot as in earlier times the steam locomotives. Therefore, the global existence of the railway companies of diesel locomotives is higher than that on electric locomotives. The disadvantages of a diesel locomotive count their complex drive mechanism and the fact that they must carry in the form of diesel fuel their energy supply. Another very significant disadvantage is that a diesel engine as opposed to electric motors and steam engines can not develop from the state of tension and that a diesel locomotive therefore suitable coupling and power transmission elements required to enable a load-free starting and running up the engine before the engine is subjected to tensile force. Since friction clutches are not available in the prevailing power classes, the electric or hydraulic power transmission has prevailed. Both are always associated with losses.
More and more railways are equipped with overhead lines ( " electrification "). Wherever an overhead line can not be economically constructed or operated (eg when crossing deserts, rough terrain, in addition to the railway sector or in shunting ), are predominantly used diesel locomotives for use.
Construction
A diesel locomotive consists of the car body with frame and the chassis and the engine and transmission components ( with cooling and auxiliary units ). There are also auxiliary operations, such as the generation of compressed air, plants for train heating and brake equipment (possibly with dynamic brake) as well as various control and safety systems. Today's locomotives usually have only one engine, earlier there were also multi-engine vehicles (such as the V 200). DB AG has signed a framework contract with Bombardier closed, which could guide the development back to multi-engine diesel locomotives. 2013, first TRAXX locomotives will be delivered with four industrial diesel engines. Depending on the required traction, then motors can be switched off and on.
Wherein the motor is usually a diesel engine, there have been or there are also the following variants:
- Gasoline locomotives propelled by gasoline engines ( this drive has been tested in the early days of diesel locomotives),
- Gas turbine locomotives propelled by gas turbines (also known as Diesel Locomotive with booster gas turbines),
- Steam - diesel locomotives (type stills ) and
- Gas engine locomotives propelled by a gas engine (currently in testing with natural gas as fuel ).
The German Reichsbahn tried the early 1930s, a diesel- pneumatic locomotive ( V 120 001), in which a cylinder engine, as it is known from the steam locomotive ago, was supplied with compressed air from a diesel compressor. This design has not been enforced.
Power transmission
The power transmission or power transmission has a diesel locomotive at the following tasks:
Moreover, the power transmission, the function of a dynamic brake enable ( hydrodynamic brake or electrical ).
Today's diesel locomotives are built with hydraulic or electric power transmission. A mechanical transmission is due to the wear-intensive synchronization during the starting only useful at low engine power ratings up to 400 kW and is therefore only used for railcars and small locomotives; Moreover, there will be interruptions in tractive power during the switching process. The mechanical power transmission was therefore (series 795 and 798 ) for years no longer used after the construction of Uerdinger rail buses. The current light- rail cars Bombardier Talent, Alstom Coradia LINT and Siemens Desiro be supplied with diesel- mechanical power transmission by ZF Ecomat transmission.
Hydraulic as well as electric power transmission allow access problems, as well as an uninterruptible tension development; both types of transmission are possible in all performance classes. The hydraulic transmission stands out thanks to a more compact design of, so it comes with most of the locomotives used today in Germany for use. Disadvantage is the relatively high mechanical maintenance costs. Are mostly used transmission with three current transformers or two transducers and a fluid coupling. There are also solutions with only two transducers; in these, however, the spreading is such that the acceleration performance to be desired. Moreover, the efficiency of the gear at the end of the curve drops off sharply. For our lower power and hydrostatic drives are used.
When diesel-electric power transmission tune large parts of the drive matches the one electric locomotive, but the electric power is generated directly on board and not externally supplied: The ensemble of generators, control and traction motors replaced clutches, transmissions and converters.
The main advantage of the diesel-electric drive compared to the hydraulic power transmission, the robust design ( lower maintenance ) and better utilization of power especially when moving. Disadvantages are mainly the higher weight and volume.
Electric power transmission is available in the following designs:
The control of the drive is done here by controlling the exciter and possibly by additional regulatory elements in front of the traction motors.
Mixed forms in design can drive their energy from both the generator and of a busbar relate ( eg, a few locomotives of the U.S. Genesis series).
Diesel-electric mainline locomotive AA16, built in GM license by the Swedish company NOHAB 1957
Ancillary businesses
In addition to the provision and transfer of energy to the traction are diesel locomotives usually have units and transmission facilities for the following ancillary businesses needed:
- Compressed air for the braking systems,
- Electrical energy in an appropriate type of current for lighting and light signals of the locomotive and the train,
- Steam or electrical energy in an appropriate type of current for train heating.
For the electric train heating and lighting additional, often called Heizdiesel diesel engines were installed in diesel-hydraulic locomotives that powered solely a generator. In diesel electric locomotives, the electric energy can be obtained from the appropriately equipped generators depending on the design of both the illumination and heating.