The EMD 645 family of diesel engines was designed and manufactured by the Electro-Motive Division of General Motors. While the 645 series was intended primarily for locomotive, marine and stationary engine use, one 16-cylinder version powered the 33-19 "Titan" prototype haul truck designed by GM's Terex 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 is still in production on a by-request basis. 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.
The 645 series engines entered production in 1965. As the 567 series had reached its limits in horsepower increases, a larger displacement was needed; this was accomplished by increasing the bore from 8-1/2 in (215.9 mm) on the 567 series to 9-1/16 in (230.2 mm) on the 645 series, while maintaining the same stroke 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 forced induction, with either a Roots-type supercharger or a turbocharger. The turbocharger (a combination turbo-compressor system) follows EMD's traditional design which uses a gear train and clutch to drive the compressor rotor during low engine speeds when exhaust heat energy alone is not sufficient. At higher engine speeds, increased exhaust heat energy is sufficient to drive the turbine, and the clutch disengages turning the turbo-compressor system into a true turbocharger. While more expensive to maintain than Roots blowers, the turbocharger significantly reduces fuel consumption and emissions in higher-throttle applications, while improving high-altitude performance.
Horsepower for supercharged diesel engines is usually derated 2.5 percent per 1,000 ft (304.8 m) above mean sea level, a tremendous penalty. At the 10,000 ft (3,048.0 m) or greater elevations which several Western U.S. and Canada railroads operate 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 and SD45) in 3,000 horsepower (2,200 kW), sixteen-cylinder form and in 3,600 horsepower (2,700 kW), 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 increases model designs by ten (such as with the 40, 50, 60 and 70 series). The number is 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-horsepower versions (such as the 45 and 75 series).
Unlike the 645 series, the 710 series does not offer a Roots-blown model, but nothing in the basic design of that engine prevents such an offering.
Specifications (many are common to 567 and 710 engines)
All 645 engines are two-stroke 45-degree V-engines. Each cylinder is of 645 cubic inches (10.57 liters) displacement, hence the name; with a bore of 9-1/16 (230.2 mm), a stroke of 10 inches (254 mm) and a compression ratio 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 which is in the center of the four exhaust valves (post-1995 engines employ an Electronic Unit injector). Rocker arms are roller-equipped to eliminate friction while hydraulic valve actuators are used to eliminate valve lash.
Cylinders in each V-pair are directly opposite each other, and since all rods are always in compression, the connecting rods use a simple system of "fork" rods on one bank of cylinders and "blade" rods on the other. Competitor General Electric in its 7FDL engine series uses more complex "articulated" connecting rods as all rods are alternately in compression or tension throughout all four engine cycles. The engines are provided with either a single or twin Roots blower, 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 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 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
- Exhaust valves: Four per cylinder
- Main bearings
- Eight cylinder: 5
- Twelve cylinder: 7
- Sixteen cylinder: 10
- Twenty cylinder: 12 (two-piece crankshaft, pinned and bolted in the middle)
- Fuel injection: Unit injector; 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 field
- AC power generator: Dual pneumatic starters in most stationary engine applications
- Engine Control
- Woodward PGE locomotive governor, or equivalent, in non-EFI-equipped engines; EMD engine control unit in EFI-equipped 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)
|ID||Number of cylinders||Induction||Max rpm||Power (hp)||Power (MW)||Introduced||Use|
|8-645C||8||Roots blown||1100||0.8||EMD G18AR, New Zealand DBR class|
|6-645E||6||Roots blown||900||750||0.6||1967||Victorian Railways Y class (G6B)|
|8-645E||8||Roots blown||900||1000||0.75||1966||SW1000, SW1001, V/Line P class, Victorian Railways T class (3rd series) / H class, CIE 201 Class (rebuilt)|
|12-645E||12||Roots blown||900||1500||1.1||1968||EMD MP15DC, GM G22 Series, CIE 001 Class (rebuilt), Commonwealth Railways NJ class,M/V Liberty Star|
|16-645E||16||Roots blown||900||2000||1.5||1966||GP38, GP38-2, SD38, SD38-2, NSWGR 422 Class, Victorian Railways X class (2nd & 3rd series) EMD G26|
|12-645C||12||Roots blown||1650||1.2||EMD G22AR, New Zealand DC class|
|12-645E3||12||Turbocharged||900||2300||1.7||1968||GP39, GP39-2, SD39, CIE 071, EMD GT22, British Rail Class 57|
|16-645E3||16||Turbocharged||900||3000||2.2||1965||GP40, GP40-2, GP40P, GP40P-2, GP40TC, SD40, SD40A, SD40-2, SD40T-2, SDP40, SDP40F, F40PH, Australian National BL Class, GT26CW, DSB Class MZ (series I–II)|
|20-645E3||20||Turbocharged||900||3600||2.7||1965||SD45, SD45-2, F45, FP45, EMD DDM45, DSB Class MZ (series III–IV)|
|16-645E3A||16||Turbocharged||950||3300||2.5||1969||DDA40X (dual engine), RENFE Class 333|
|12-645E3B||12||Turbocharged||904||2380-2570||1.8-1.9||JT22CW, V/Line A class, V/Line N class (2nd series),|
|16-645E3B||16||Turbocharged||904||3195-3390||2.4-2.5||F40C, V/Line G class (original), NSB Di 4, DSB Class ME, New South Wales 81 class locomotive|
|12-645E3C||12||Turbocharged||2510||1.8||V/Line N class (1st series), New Zealand DFT class|
|16-645E3C||16||Turbocharged||904||3300||2.5||British Rail Class 59, Pacific National XRB class, Freight Australia XR class, VL class (Australia), CL class (rebuilt versions), Australian National ALF class, TCDD DE33000|
|16-645E4||16||Turbocharged||900||3300||2.46||1973||Terex 33-19 "Titan" haul truck|
|16-645F||16||Turbocharged||950||3500||2.6||1977||GP40X, GP50, SD40X, SD50|
|16-645F3B||16||Turbocharged||904||3600||2.7||FT36HCW-2-Korail 7000 Series; MPI MPXpress MP36PH-3S and -3C, CFCLA RL class, V/Line G class (rebuilt)|
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.
- 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 - 800 RPM / 900 RPM
- 8-cylinder . . . . ---- / 1525
- 12-cylinder . . . .2305 / 2550
- 16-cylinder . . . .3070 / 3400
- 20-cylinder . . . .3600 / 4000
- Foster, Gerald (1996). A Field Guide to Trains. Boston, New York: Houghton Mifflin Company.
- U.S. Patent 1,981,913
- Service power assemblies are available from EMD, and from competitors, as "Fork", P/N 40118490, "Blade", P/N 40118491, and "Partial" (neither "Fork" nor "Blade"), P/N 40173918.
- Even firing: an ignition event every 45 degrees of crankshaft rotation; directly opposite pairs of cylinders, (1, 5), (2, 6), etcetera, always fire 45 degrees apart, which is a multiple (1) of 45 degrees.
- Uneven firing: an ignition event approximately every 30 degrees of crankshaft rotation; these uneven ignition events are often measurably shorter or longer than 30 degrees, the average over all ignition events; directly opposite pairs of cylinders, (1, 7), (2, 8), etcetera, always fire 45 degrees apart, however.
- Even firing: an ignition event every 22.5 degrees of crankshaft rotation; directly opposite pairs of cylinders, (1, 9), (2, 10), etcetera, always fire 45 degrees apart, which is a multiple (2) of 22.5 degrees.
- Uneven firing: an ignition event approximately every 18 degrees of crankshaft rotation; these uneven ignition events are often measurably shorter or longer than 18 degrees, the average over all ignition events; directly opposite pairs of cylinders, (1,11), (2,12), etcetera, always fire 45 degrees apart, however.
- 8-645C engines were 8-567C engines which were updated with 645 "power assemblies"; normally a 645 engine employs an E or F block and their designation is 645E or 645F; the 567 engine has a significantly different oil sump and frame mounting than the later 645 or 710 engine, hence a "645C" engine is a hybrid, possibly rated as a 645 engine, but physically more like an earlier 567 engine
- Christensen, Peter; John Poulsen (1999). Motor Materiel 5: Med motor fra GM (in Danish). bane bøger. p. 100. ISBN 87-88632-79-2.
- "Terex 33-19 Hauler Form No. GMD 1946" (PDF). Canada: Terex Division of General Motors Corporation. December 1974. p. 1. Retrieved 2010-08-30. "Gross HP @ 900 RPM ... 3300"
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