Two new Cat wheeled excavator models, the M318F and M320F, have maximum operating weights of 21.7 and 23.2 tons, respectively, and use the Cat C7.1 engine, which is rated at 169 net horsepower and meets Tier 4-Final emissions standards. Equipped with an engine-idle-shutdown system and an ECO mode designed to reduce engine speed with no compromise in power, the new excavators, says Caterpillar, can deliver up to 10 percent better fuel economy in certain applications, compared with predecessor models. Further fuel savings, says the company, result from reducing load on the engine by replacing gear-type pumps with new variable-displacement pumps in the medium-pressure and cooling-fan circuits.
An operator-enabled system automatically senses machine parameters and locks the axle-oscillation function and sets the service brakes to prepare the machine to dig. Brakes and axle lock are automatically released when the operator presses the travel pedal. A new travel-lock system is engaged via a switch on the panel and combines implement-stop and swing-lock functions. Cruise control is a standard feature. A new blade has a redesigned profile that allows it to remain parallel to the ground at any height and also facilitates material movement in front of the blade.
The exterior of the new models has been completely restyled, including a completely new ROPS-compliant operator's cabin featuring higher pressurization, larger door with added glass, new windshield with parallel wipers, new mirrors (with a heated option), new rain visor and light protectors and a larger skylight. The standard rearview camera is housed in the redesigned counterweight, and an available right-side camera has a separate in-cab monitor.
The engine in the new models, as in predecessor models, is longitudinally mounted with the cooling package forward of the engine, resulting, says Caterpillar, in easy, ground-level access to routine maintenance points. An electric fuel-priming pump eliminates filling filters before installation, all the radiators are placed in the same compartment, and the condenser can be tilted for ease of cleaning. Electrical and hydraulic components are grouped in specific areas for ease of service, and an automatic centralized greasing device (Auto-lube) is standard.
Cat M318F, M320F Specifications
- Engine: Cat C7.1 ACERT, Tier 4-F
- Net power: 169 horsepower
- Max weight, M318F: 21.7 tons
- Max weight, M320F: 23.2 tons