Caterpillar K Series Small Wheel Loaders — 924K, 930K, and 938K — feature the Caterpillar Hystat system, an electronically controlled hydrostatic transmission that delivers smooth, step-less power through four speed ranges and automatically adjusts tractive power at the wheels to match underfoot conditions. Control of the Hystat system has been further refined for these models by adding the Hystat Operator Modes feature, which allows operators to adjust Hystat performance to suit operating conditions or individual preferences
In addition to the Default setting, the new control system provides three performance settings, selected via the optional K-Series Secondary Display or the Cat Electronic Technician: Hystat Mode; TC (Torque Converter) Mode; and Ice Mode.
The Hystat Mode fine-tunes the hydrostatic-drive system for peak performance. The governor pedal (ground-speed controller) will more directly control machine movement, proportionally accelerating the machine when applied and quickly but smoothly slowing the machine to a stop when released. In Hystat Mode, the machine will not move when placed in gear at low idle until the governor pedal is depressed.
In the TC Mode, the hydrostatic transmission functions with the characteristics of a conventional torque-converter-equipped machine, allowing the machine to coast, for example, when the operator releases the governor pedal. A slope-compensation feature allows the machine to respond with torque-converter-like performance on uphill and downhill grades, and the TC mode also modulates (“softens”) shifts to neutral and reduces low-idle wheel torque.
The Ice Mode adjusts hydrostatic response to provide enhanced control specifically on near-zero-friction surfaces, such as ice and hard-packed snow, by lengthening and further modulating directional shifts. This mode is not intended for use on slippery mud surfaces, nor on ice/snow surfaces when operating with studded tires or tire chains.