Caterpillar 770G, 772G Off-Highway Trucks

Caterpillar 770G and 772G off-highway trucks have nominal rated payload capacities of 40 and 52 tons, respectively, and use Cat C15 (770G) and C18 (772G) engines, with net power ratings of 477 (770G) and 550 (772G) horsepower.

Available in Tier 2/Stage II, Tier 3/Stage III, and Tier 4-Final/Stage IV configurations, the engines can be programmed to achieve the customer's specific fuel economy goals, Caterpillar says. Two programmable modes are available: Economy and Adaptive Economy.

Economy Mode lets the customer select a derate value between .5% and 15%. Then, at the touch of a button, Economy Mode applies steady power deration across all portions of the haul cycle. According to the company, with Adaptive Economy Mode, the truck monitors power demand, delivering fuel savings when possible and horsepower when needed, to optimize fuel economy throughout the haul cycle.

The Auto Neutral Idle feature automatically places the transmission in Neutral gear after the brake is applied for more than 15 seconds while in a forward gear. Once the operator removes his foot from the brake, the transmission re-engages. This is completely transparent to the operator. Also, a hydraulically driven, on-demand cooling fan reduces power draw on the engine by operating only when required and only at the speed required.

The new transmission control system, Advanced Productivity Electronic Control Strategy (APECS), provides a number of benefits, Cat says, including improved shift quality, faster acceleration, better speed on grade and faster cycle times.

This control strategy modulates shift points to match optimum operating speed and torque, minimizes torque spikes during shifts and reduces stress on the drive train.

An optional advanced Traction Control System uses the service brakes instead of the park brake components to modulate wheel slip. This change in design makes the system much more responsive to traction loss in the lower speed ranges, and improves speed on grade in wet, slippery conditions. This new system also assesses front wheel steering angle when determining traction slippage and adjusts the degree of allowance in wheel speed differential that naturally increases between the inside and outside wheels when the machine is turning. By assessing steering angle, it compensates for the outside wheel turning at a higher speed to improve traction.