EMD 710

EMD 710
An EMD 12-710G3B engine, installed in an Iarnród Éireann 201 class locomotive
Overview
Manufacturer	Electro-Motive Diesel
Also called	G-Engine
Production	1983-present
Layout
Configuration	V8, V12, V16, and V20
Displacement	710 cubic inches (11,600 cm3) per cylinder
Cylinder bore	9+1⁄16 in (230 mm)
Piston stroke	11 in (280 mm)
Cylinder block material	Flat, formed and rolled structural steel members, and steel forgings, integrated into a weldment
Cylinder head material	Cast iron, one per cylinder
Valvetrain	4 Valves per cylinder, SOHC
Compression ratio	15.3:1
RPM range
Idle speed	200
Max. engine speed	900-904-906-910-950
Combustion
Supercharger	Centrifugal
Turbocharger	Hybrid turbocharger, below half throttle, clutch-driven blower takes over
Fuel system	Unit injector, actuated by engine camshaft
Management	Electronic
Fuel type	Diesel
Oil system	Wet sump
Cooling system	Liquid cooling
Output
Power output	203 kilowatts (272 hp) per cylinder
Dimensions
Dry weight	up to 25.57 tonnes (25.17 long tons; 28.19 short tons)
Chronology
Predecessor	EMD 645
Successor	EMD 1010 - the heavily redesigned and refined EMD 265H to meet Tier-4 emission standard

The EMD 710 is a line of diesel engines built by Electro-Motive Diesel (previously General Motors' Electro-Motive Division). The 710 series replaced the earlier EMD 645 series when the 645F series proved to be unreliable in the early 1980s 50-series locomotives which featured a maximum engine speed of 950 rpm.^{[note 1]} The EMD 710 is a relatively large medium-speed two-stroke diesel engine that has 710 cubic inches (11.6 liters) displacement per cylinder,^[1] and a maximum engine speed of 900 rpm.^{[note 2]}

In 1951, E. W. Kettering (son of Charles F. Kettering) wrote a paper for the ASME entitled, History and Development of the 567 Series General Motors Locomotive Engine,^[2] 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 development of the 567C, applying a cylinder bore increase (645) and a stroke increase (710), to achieve a greater power output, without changing the external size or weight of the engines, thereby achieving significant improvements in horsepower per unit volume and horsepower per unit weight.

Since its introduction, EMD has continually upgraded the 710G diesel engine. Power output has increased from 3,800 horsepower (2,800 kW) on 1984's 16-710G3A to 4,500 horsepower (3,400 kW) (as of 2012) on the 16-710G3C-T2, although most current examples are 4,300 horsepower (3,200 kW).

The 710 has proved to be exceptionally reliable, but the earlier 645 is still supported and most 645 service parts are still in new production, as many 645E-powered GP40-2 and SD40-2 locomotives are still operating after four decades of service, and these often serve as a benchmark for engine reliability, which the 710 would meet and eventually exceed, and quite a number of non-SD40-2 locomotives (SD40, SD45, SD40T-2, and SD45T-2, for example, and even some SD50s), have been rebuilt to the equivalent of SD40-2s with new or remanufactured engines and other subsystems, using salvaged locomotives as a starting point. Some of these rebuilds have been made using new 12-cylinder 710 engines in place of the original 16-cylinder 645 engines, retaining the nominal rating of 3000 horsepower, but with lower fuel consumption.

Over the production span of certain locomotive models, upgraded engine models have been fitted when these became available. For example, an early 1994-built SD70MAC had a 16-710G3B, whereas a later 2003-built SD70MAC would have a 16-710G3C-T1.

The engine is made in V8, V12, V16, and V20 configurations, although most current locomotive production is the V16 engine, whereas most current marine and stationary engine production is the V20 engine.

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