Caterpillar has recently introduced a new family of diesel-fuelled generator sets in the two to four MW power range, which are now available in the Gulf through Sharjah-based Mohammed Abdulrahman Al Bahar, the company’s authorised dealer in the region.

This new family of generator sets builds on the success of the Caterpillar 3500 series of generator sets. It is powered by the new Cat C175 engine – the first to offer up to 4 MW of power in a single high-speed package, says a spokesman for Caterpillar, a world-leading manufacturer of construction and mining equipment, diesel and natural gas engines and industrial gas turbines.
“The new Cat C175 has been specifically engineered to address the current and future needs of the worldwide electric power industry. It is the result of extensive customer research to identify key product benefits sought by our engine and generator set customers,” says William J Rohner, vice president of Caterpillar Electric Power Division. “This new line of generator sets powered by the C175 engine offers unprecedented value for our customers. We have incorporated numerous features to reduce power plant installed costs and operating costs.”
The new family of diesel generator sets is designed for standby, prime, continuous and load management applications requiring a large amount of power in industry segments including healthcare, commercial, institutional, government, public services, data centres, energy utilities, manufacturing, industrial, logistics and communications.
“Offering the latest developments in engine architecture, this new family provides superior performance, reliability and durability. In addition, the generator sets provide emissions compliance without sacrificing on power density or fuel economy,” says the spokesman.
Five key engine systems comprise the Cat C175: the air system, fuel system, electronics and controls, cooling system, and lube system.
“During the development of the C175 engine, dedicated teams were assigned to each of the engine systems and major components to ensure superior engineering, product performance, and the ability of this new family of generator sets to meet the identified needs of our customers,” explains Rohner.
Of the five engine systems, the air system, fuel system, and electronics and controls make up the building blocks of Advanced Combustion Emission Reduction Technology (Acert) Technology, which was recently introduced by Caterpillar for electric power customers last year. Caterpillar has invested more than $500 million in a three-year research and development programme to develop the revolutionary Acert Technology as the platform for long-term emissions compliance.

Air system
The C175 air system was designed to enhance engine breathing using a tall cross-flow cylinder head.
“This head has been designed with larger ports to allow more cool, clean air into the combustion chamber at high volumetric efficiency,” he explains. “The cross-flow head design helps provide the engine with higher power density and reduced cooling needs by minimising heat transfer between both the intake and exhaust ports, as well as the manifolds.
“The air system also contains a highly efficient turbocharger with a cast titanium compressor impeller that helps extend turbocharger life to at least one major overhaul, translating into 24,000 hours for 60 Hz, 1800 rpm, and 28,000 hours for 50 Hz, 1500 rpm models.”

Fuel
“A building block of both Acert Technology and the C175 engine design is the Cat Common Rail Fuel System (CRFS),” he continues. “This fuel system, controlled by the Adem A4 Electronic Control Module, utilizes a high-pressure fuel pump and control valve to maintain the desired fuel rail pressure. The Cat CRFS has the capability to deliver multiple injections within a single combustion event with unprecedented precision and repeatability. Each injection event is precisely controlled in timing and volume to maximize combustion efficiency and reduce emissions. The precise control also helps provide superior transient response, block load acceptance and cold start capability.”

Advanced electronic controls
Rounding out the building blocks of Acert Technology is the C175 engine platform’s electronics and controls. As part of an integrated system, the Adem A4 controller works to provide low fuel consumption and reduce emissions. It also precisely maintains coolant temperature and oil viscosity to add reliability and durability to all engine parts, he says.
Advanced electronic controls ease troubleshooting and offer diagnostic information. For example, the electronic coolant temperature controller allows troubleshooting without removing the thermostat, which increases engine uptime and improves overall reliability, the spokesman points out.

Cooling
He continues: “The C175 engine’s cooling system has been designed to minimise heat rejection and obtain higher overall engine efficiency by only targeting areas of the engine requiring cooling, as demonstrated by the mid-support cylinder liners. In addition, the length of the exhaust port is reduced to minimise unnecessary heat rejection into the jacket water.
“The cooling system’s two-stage after cooler is composed of robust tube and fin cores that improve system reliability and durability. An integral water return manifold minimises connection points and bolted joints, which also improves the reliability and serviceability of the overall system.

Lube system
“The lube system contributes to the engine’s overall reliability and durability and features a pressure regulation valve that allows the engine to maintain optimum oil pressure at all speeds and loads. It also improves cold start capability by providing full-gallery oil pressure in less than four seconds. With the robust design of the lube system and components, oil change intervals are increased from the typical 500 hours to 600 hours, reducing operating costs for customers.”
The engine design includes technological enhancements and advances in major components such as the crankshaft, bearings, piston, rod, block, liner, head, valves and valve mechanism, and camshaft.
The large bearing journals provide the desired reliability and durability that have been demonstrated in the Cat 3500 series engine product line.
The generator – available in low, medium and high voltages – has been specifically designed for the C175 engine platform. Its insulation system meets Class H insulation system requirements, has two-thirds pitch and additionally features the Cat digital voltage regulator with microprocessor-based VAR/power factor control and direct three-phase sensing.
The generator features either a traditional permanent magnet excitation, or a new internal excitation option, which is capable of 300 per cent short circuit and replaces self-excitation as the low-cost alternative to a permanent magnet with equivalent performance. Other features of the SR5 generator include two-thirds pitch and IP23 particle ingress protection.
The C175 controls package includes a standard Electronic Modular Control Panel (EMCP) 3 control system that offers enhanced monitoring and controls while providing flexibility and site-specific configurations.
“The EMCP 3 controller combines engine and generator control and monitoring into a single, digital panel for quick-key access to engine and generator controls, diagnostics and operating information. It communicates over a common J1939 package network and has modbus communication capability,” the spokesman says.
Two types of radiator packages, a horizontal remote and vertical radiator, are also available for the C175. Both are tube and fin with mechanically bonded tube-to-header joints that enhance the reliability and durability of the package. Two-speed fan control optimises parasitic loads and noise.
Caterpillar products and components are manufactured in 50 US facilities and in over 60 other locations, in 23 countries around the globe. Caterpillar, which earned sales revenue of $36.34 billion last year, offers worldwide product support with parts and service available globally through the Cat dealer network.
Its dealer in the region, Mohamed Abdulrahman Al -Bahar has offices spread throughout the Middle East in the UAE, Kuwait, Qatar, Oman (Oasis Trading and Equipment Company) and Bahrain.