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The EMD 645 is a family of two-stroke diesel engines that was designed and manufactured by the
Electro-Motive Division Electro-Motive Diesel (abbreviated EMD) is a brand of diesel-electric locomotives, locomotive products and diesel engines for the rail industry. Formerly a division of General Motors, EMD has been owned by Progress Rail since 2010. Electro-Motiv ...
of
General Motors General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. The company is most known for owning and manufacturing f ...
. While the 645 series was intended primarily for
locomotive A locomotive is a rail transport, rail vehicle that provides the motive power for a train. Traditionally, locomotives pulled trains from the front. However, Push–pull train, push–pull operation has become common, and in the pursuit for ...
, marine and stationary engine use, one 16-cylinder version powered the 33-19 "Titan" prototype haul
truck A truck or lorry is a motor vehicle designed to transport freight, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construct ...
designed by GM's
Terex Terex Corporation is an American company and worldwide manufacturer of materials processing machinery, waste and recycling equipment, mobile elevating work platforms, and equipment for the electric utility industry. Terex does business in the ...
division The 645 series was an evolution of the earlier 567 series and a precursor to the later 710 series. First introduced in 1965, the EMD 645 series remained in production on a by-request basis long after it was replaced by the 710, and most 645 service parts are still in production. The EMD 645 engine series is currently supported by Electro-Motive Diesel, Inc., which purchased the assets of the Electro-Motive Division from General Motors in 2005. EMD is currently owned by Progress Rail (since 2010). In 1951, E. W. Kettering wrote a paper for the
ASME The American Society of Mechanical Engineers (ASME) is an American professional association that, in its own words, "promotes the art, science, and practice of multidisciplinary engineering and allied sciences around the globe" via "continuing edu ...
entitled, ''History and Development of the 567 Series General Motors Locomotive Engine'', which goes into great detail about the technical obstacles that were encountered during the development of the 567 engine. These same considerations apply to the 645 and 710, as these engines were a logical extension of the 567C, by applying a cylinder bore increase, 645, and a cylinder bore increase ''and'' a stroke increase, 710, to achieve a greater power output, without changing the external size of the engines, or their weight, thereby achieving significant improvements in power per unit volume and power per unit weight. Due to emissions restrictions these engines have been gradually phased out for the four-stroke alternatives.


History

The 645 series engines entered production in 1965. As the 567 series had reached its limits in output power increases, a larger displacement was needed; this was accomplished by increasing the bore from on the 567 series to on the 645 series, while maintaining the same
stroke Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...
and deck height. While the crankcase was modified from the 567 series, 567C and later engines (or 567 engines which have been modified to 567C specifications, sometimes referred to as 567AC or 567BC engines) can accept 645 series service parts, such as power assemblies. Conversely, the 567E engine employs a 645E series block with 567 series power assemblies. All 645 engines utilize either a
Roots blower The Roots blower is a positive displacement lobe pump which operates by pumping a fluid with a pair of meshing lobes resembling a set of stretched gears. Fluid is trapped in pockets surrounding the lobes and carried from the intake side to th ...
or a turbocharger for cylinder scavenging. For turbocharged engines, the turbocharger is gear-driven and has an overrunning clutch that allows it to act as a centrifugal blower at low engine speeds (when exhaust gas flow and temperature alone are insufficient to drive the turbine) and a purely exhaust-driven turbocharger at higher speeds. The turbocharger can revert to acting as a supercharger during demands for large increases in engine output power. While more expensive to maintain than Roots blowers, EMD claims that this design allows "significantly" reduced fuel consumption and emissions, improved high-altitude performance, and even up to a 50 percent increase in maximum rated output power over Roots-blown engines for the same engine displacement. Output power for
naturally aspirated A naturally aspirated engine, also known as a normally aspirated engine, and abbreviated to N/A or NA, is an internal combustion engine in which air intake depends solely on atmospheric pressure and does not have forced induction through a turboc ...
engines (including Roots-blown two-stroke engines) is usually derated 2.5 percent per above mean sea level, a tremendous penalty at the or greater elevations which several Western U.S. and Canada railroads operate, and this can amount to a 25 percent power loss. Turbocharging effectively eliminates this derating. The 645 series has a maximum engine speed of between 900 and 950 revolutions per minute (rpm), an increase over the 800 to 900 rpm maximum speed for the 567 series. An engine speed of 900 rpm was essential for 60 Hz stationary power generator applications and certain passenger locomotives equipped with 60 Hz, 480-volt three-phase "head-end power" systems. When used solely for traction purposes, the engine speed varies depending on the throttle position. The 950 rpm maximum speed of the 645F engine proved to be too high, thereby compromising its reliability, and the replacement engine, the 710G, reverted to 900 rpm maximum speed. EMD built an SD40 demonstrator (number 434) in July 1964 to field test the 16-645E3 engine, followed by another eight SD40 demonstrators (numbers 434A through 434H) and a GP40 demonstrator (number 433A) in 1965. In December 1965 and January 1966, EMD built three SD45 demonstrators (numbers 4351 through 4353) to field test the 20-645E3 engine. When the 645 engine entered production in 1965, a large series of new locomotive models was introduced. The turbocharged version was used in EMD's ''40 Series'' ( GP40,
SD40 SD40 may refer to: * Canon PowerShot SD40, a digital camera * EMD SD40, a diesel-electric locomotive * South Dakota Highway 40 * SD-40 alcohol, ethanol denatured alcohol, denatured by adding denatonium benzoate * School District 40 New Westminster, ...
and SD45) in , sixteen-cylinder form and in , twenty-cylinder form. EMD also introduced the Roots-blown ''38 Series'' ( GP38, SD38) and turbocharged, twelve-cylinder ''39 Series'' ( GP39, SD39). All of these locomotive models extensively share common components and subsystems, thereby significantly reducing cost and increasing interchangeability. The GP38-2 and SD40-2 became the most popular models of the series and among the most popular locomotive models ever built. Starting with the introduction of the 645 series engines, EMD's model naming convention generally increased model designs by ten (such as with the 40, 50, 60 and 70 series). The number was reduced by one for twelve-cylinder versions (such as the 39, 49 and 59 series); reduced by two for Roots-blown versions (for the 38 series); and increased by five for higher-power versions (such as the 45 and 75 series).


Specifications (many are common to 567 and 710 engines)

All 645 engines are
two-stroke A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes of the piston, one up and one down, in one revolution of the crankshaft in contrast to a four-stroke engine which re ...
45-degree
V-engine A V engine, sometimes called a Vee engine, is a common configuration for internal combustion engines. It consists of two cylinder banks—usually with the same number of cylinders in each bank—connected to a common crankshaft. These cylinder b ...
s. Each
cylinder A cylinder () has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infinite ...
is of
displacement Displacement may refer to: Physical sciences Mathematics and physics *Displacement (geometry), is the difference between the final and initial position of a point trajectory (for instance, the center of mass of a moving object). The actual path ...
, hence the name; with a bore of , a
stroke Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...
of and a
compression ratio The compression ratio is the ratio between the maximum and minimum volume during the compression stage of the power cycle in a piston or Wankel engine. A fundamental specification for such engines, it can be measured in two different ways. Th ...
of 14.5:1. The engine is a uniflow design with four poppet-type exhaust valves in the cylinder head and charge air scavenging ports within the sides of the cylinders. All engines use a single overhead camshaft per bank, with exhaust valves operated by two cam lobes (each of which operates two exhaust valves through a "bridge") and one cam lobe to operate the
Unit injector A unit injector (UI) is a high-pressure integrated direct fuel injection system for diesel engines, combining the injector nozzle and the injection pump in a single component. The plunger pump used is usually driven by a shared camshaft. In a ...
which is in the center of the four exhaust valves. Rocker arms are roller-equipped to reduce friction while hydraulic valve actuators are used to reduce valve lash. Post-1995 710 engines employ Electronic Unit injectors, however these injectors still utilize a camshaft-actuated piston pump, as on non-EFI injectors. Cylinders in each V-pair are directly opposite each other, and the connecting rods are of a fork-and-blade arrangement, with "fork" rods on one bank of cylinders and "blade" rods on the other (with the same stroke on both banks). (In contrast, General Electric's 7FDL and 7FDM engines use "articulated" master-and-slave connecting rods, essentially two adjacent cylinders on a
radial engine The radial engine is a reciprocating engine, reciprocating type internal combustion engine, internal combustion engine configuration in which the cylinder (engine), cylinders "radiate" outward from a central crankcase like the spokes of a wheel. ...
, and have a slightly longer stroke on the bank using slave rods.)Service power assemblies are available from EMD, and from competitors, as "Fork", "Blade", and "Partial" (neither "Fork" nor "Blade"), P/N 40173918. The engines are provided with either a single or twin
Roots blower The Roots blower is a positive displacement lobe pump which operates by pumping a fluid with a pair of meshing lobes resembling a set of stretched gears. Fluid is trapped in pockets surrounding the lobes and carried from the intake side to th ...
, or a single mechanically-assisted turbocharger, depending on required power output. For maintenance, a power assembly, consisting of a cylinder head, cylinder liner, piston, piston carrier and piston rod can be individually replaced relatively easily and quickly. The engine block is made from flat, formed and rolled
structural steel Structural steel is steel used for making construction materials in a variety of shapes. Many structural steel shapes take the form of an elongated beam having a profile of a specific cross section (geometry), cross section. Structural steel sha ...
members and steel forgings welded into a single structure (a "weldment"), so it can easily be repaired using conventional shop tools. *Orientation: The "front" of the engine (the engine governor and fluid pump end) is actually at the rear end of the locomotive, immediately adjacent to the locomotive's coolant supply and cooling system; the "rear" of the engine (the induction system and traction generator or
alternator An alternator (or synchronous generator) is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating magnetic field wit ...
end) is at the front end of the locomotive, immediately adjacent to the locomotive's electrical cabinet. *Rotation: Engine rotation is in the conventional clockwise direction, as viewed from the "front" of the engine, but is in a counterclockwise direction, as viewed from the front of the locomotive. Marine and stationary installations are available with either a left or a right-hand rotating engine. *Firing order **Eight cylinder: 1, 5, 3, 7, 4, 8, 2, 6Even firing: an ignition event every 45 degrees of crankshaft rotation; directly opposite pairs of cylinders always fire 45° apart. **Twelve cylinder: 1, 7, 4, 10, 2, 8, 6, 12, 3, 9, 5, 11Odd firing: ideally, an ignition event would occur every 30° of crankshaft rotation; however, each pair of cylinders always fires 45° apart. As a result, the firing intervals alternate between 45° and 15°. **Sixteen cylinder: 1, 8, 9, 16, 3, 6, 11, 14, 4, 5, 12, 13, 2, 7, 10, 15Even firing: an ignition event every 22.5° of crankshaft rotation. Since each pair of cylinders always fires 45° apart, the engine fires in a right-right-left-left fashion. **Twenty cylinder: 1, 19, 8, 11, 5, 18, 7, 15, 2, 17, 10, 12, 3, 20, 6, 13, 4, 16, 9, 14Odd firing: To achieve even firing, the firing intervals must be 18°. However, each pair of cylinders always fire 45° apart. As a result, the firing intervals alternate between 9° and 27°. *Exhaust valves: Four per cylinder *Main bearings **Eight cylinder: 5 (one-piece crankshaft) **Twelve cylinder: 7 (one-piece crankshaft) **Sixteen cylinder: 10 (two-piece crankshaft, pinned and bolted in the middle) **Twenty cylinder: 12 (two-piece crankshaft, pinned and bolted in the middle) *Fuel injection:
Unit injector A unit injector (UI) is a high-pressure integrated direct fuel injection system for diesel engines, combining the injector nozzle and the injection pump in a single component. The plunger pump used is usually driven by a shared camshaft. In a ...
; Electronic unit injector in post-1995 engines *Engine starting **AC traction generator: Dual electric starting motors, parallel-connected 64 volt starters in early applications, series-connected 32 volt starters in late applications **DC traction generator: Generator series field **AC power generator: Dual pneumatic starters in most stationary engine applications *Engine Control ** Woodward PGE locomotive governor, or equivalent, in mechanical engines; EMD engine control unit in electronic engines *Weight (E3B turbocharged models) **Eight cylinder: 22,050 pounds (10.0 tonnes) **Twelve cylinder: 28,306 pounds (12.8 tonnes) **Sixteen cylinder: 36,425 pounds (16.5 tonnes) **Twenty cylinder: 43,091 pounds (19.5 tonnes)


Versions


Stationary/marine versions

Like most EMD engines, the 645 is also sold for stationary and marine applications. Stationary and marine installations are available with either a left- or right-hand rotating engine. Marine engines differ from railroad and stationary engines mainly in the shape and depth of the engine's oil sump, which has been altered to accommodate the rolling and pitching motions encountered in marine applications. Engine speed *Full: 900 RPM for 60 Hz power generation; 750 RPM for 50 Hz power generation; variable up to 900 RPM for marine applications *Idle: 350 RPM *Compression ratio: 16:1 Brake horsepower (ABS rating) *Model 645E6 engines, 900 RPM **8-cylinder: 1050 **12-cylinder: 1500 **16-cylinder: 1950 *Model 645E7C/F7B engines at 800 and 900 RPM **8-cylinder: , 1525 **12-cylinder: 2305, 2550 **16-cylinder: 3070, 3400 **20-cylinder: 3600, 4000


See also

*
EMD 567 The EMD 567 is a line of large medium-speed diesel engines built by Electro-Motive Diesel, General Motors' Electro-Motive Division. This engine, which succeeded Winton Motor Carriage Company, Winton's 201A, was used in EMD's locomotives from 193 ...
* EMD 710 * EMD 1010


Notes


References


External links

* * * {{Progress Rail Services Diesel locomotive engines Marine diesel engines Two-stroke diesel engines V6 engines V8 engines