EMD 645 - Specifications (Many Are Common To 567 and 710 Engines)

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 nine and one-sixteenth inches (230.2 mm), a stroke of ten inches (254 mm) and a compression ratio of 14.5:1. The 710, 645 and 567 are the only two-stroke engines commonly used today in locomotives. The engine is a uniflow design with exhaust valves in the cylinder head. For maintenance, a power assembly, consisting of a cylinder head, cylinder liner, piston, piston carrier and piston rod can be individually and relatively easily and quickly replaced. The block is made from flat, formed and rolled structural steel members and steel forgings welded into a single structure (a "weldment"). Blocks may, therefore, be easily repaired, if required, using conventional shop tools. Cylinders in each V-pair are directly opposite each other, requiring "fork" connecting rods for one bank of cylinders and enabling "blade" connecting rods for the opposite bank of cylinders as all rods are always in compression throughout both engine cycles (competitor General Electric uses the more complicated "articulated" connecting rods as all rods are alternately in compression or tension throughout all four engine cycles and the simpler "blade" connecting rods cannot operate in tension). The engines are provided with either a single or twin Roots blower, or a single mechanically-assisted turbocharger, depending on required power output. All engines are single-overhead cam type (one cam per bank) with two cam lobes to operate the exhaust valves (each exhaust cam lobe 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 710 engines have electronically-controlled injectors which fit within the same space as a Unit injector and operate as a Unit injector except that the injection timing (but not the injection itself) is electronically controlled. Rocker arms are roller-equipped to eliminate friction. Hydraulic valve actuators are employed to eliminate valve lash. The basic system design has been successfully utilized for over 75 years of service.

• Orientation: the "front" of the engine (the engine governor and fluid pump end) is actually at the rear end of the locomotive; the "rear" of the engine (the induction system and traction generator or alternator end) is actually at the front end of the locomotive; 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.

• Rotation (facing rear of locomotive): Counterclockwise
• Firing order
  • Eight cylinder: 1, 5, 3, 7, 4, 8, 2, 6
  • Twelve cylinder: 1, 12, 7, 4, 3, 10, 9, 5, 2, 11, 8, 6
  • Sixteen cylinder: 1, 8, 9, 16, 3, 6, 11, 14, 4, 5, 12, 13, 2, 7, 10, 15
  • Twenty cylinder: 1, 19, 8, 11, 5, 18, 7, 15, 2, 17, 10, 12, 3, 20, 6, 13, 4, 16, 9, 14
• Exhaust valves: Four per cylinder
• Main bearings
  • Eight cylinder: 5
  • Twelve cylinder: 7
  • Sixteen cylinder: 10
  • Twenty cylinder: 12
• Fuel injection: Unit injector; Electronic unit injector in post-1995 engines
• Engine starting
  • AC traction generator: Dual electric starting motors (dual pneumatic starting motors in stationary engines)
  • DC traction generator: Generator field
• 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)