The Caterpillar C175-20 diesel engine stands more than 8 feet tall and is capable of cranking out 16,474 lb-ft of torque. The 20-cylinder mammoth is used to power the gigantic Cat 797F mining truck that has a payload of 400 tons, but when it's hooked to a generator, it's able to create up to 4 megawatts of electricity. That's enough power to run more than 350 average American homes according to the federal government. In fact, a single C175-20 engine is powering the entire island of Mustique in the Caribbean.

The C175-20 is a 105.8L, four-stroke, water-cooled, biodiesel-capable engine with four turbochargers and Caterpillar's ACERT common-rail fuel injection system, which helps keep fuel consumption low and recovery time short and improves starting in cold weather. With the power generation equipment attached, it weighs in at 51,588 pounds and measures 21.8 feet long by 7.6 feet wide. The engine has a single block made of cast iron; a steel-forged crankshaft; two piston-cooling jets per cylinder; and tall, four-valve (80 in total) cross-flow cylinder heads with large ports. The large displacement of 6,456 cubic inches and low operating speed of 1,800 rpm are designed to keep the engine running reliably.

The engine design uses long, 8.66-inch power strokes for optimum efficiency. The C175-20 has a large oil capacity of 178.3 gallons and a pressure regulation valve to help maintain optimum oil pressure at all engine speeds and loads. The intake rate is a gigantic 11,946 cubic feet per minute and the maximum exhaust gas temperature is a fairly cool 894 degrees when the "gen set" is operating at maximum output. The C175 engine is also available in a 16-cylinder configuration that's used for everything from running the drills on offshore oil rigs to powering locomotives.

Generator Configurations

The C175-20 "gen set" is available in numerous configurations for different uses ranging from constant power output to duty as an emergency backup.

Standby: Output available with varying load for the duration of the interruption of the normal source power. Average power output is 70 percent of the standby power rating. Typical operation is 200 hours per year, with maximum expected usage of 500 hours per year.

Mission Critical: Output available with varying load for the duration of the interruption of the normal source power. Average power output is 85 percent of the mission critical power rating. Typical peak demand up to 100 percent of the mission critical rated ekW for 5 percent of the operating time. Typical operation is 200 hours per year, with maximum expected usage of 500 hours per year.

Prime: Output available with varying load for an unlimited time. Average power output is 70 percent of the prime power rating. Typical peak demand is 100 percent of prime rated ekW with 10 percent overload capacity for emergency use for a maximum of 1 hour in 12. Overload operation cannot exceed 25 hours per year.

Continuous: Output available with non-varying load for an unlimited time. Average power output is 70 to 100 percent of the continuous power rating. Typical peak demand is 100 percent of the continuous rated ekW for 100 percent of the operating hours.