Abstract: A towed scraper control system automatically lowers the scraper blade to a working position at the start of a scraping operation according to a certain method. The method includes sensing a ground speed of the vehicle and sensing a draft force applied by the scraper to the vehicle. With the vehicle pulling the scraper at or near a target ground speed over terrain with the blade positioned above a surface of the ground, the blade is automatically lowered with respect to the scraper frame at a first rate until the blade begins to engage the surface of the ground. Thereafter, while the vehicle continues to move forward at or near the target ground speed, the blade is lowered with respect to the frame at a second rate and for a duration related to the sensed ground speed so that lowering of the blade stops when the scraper wheel begins to enter a cut produced by the blade.

Abstract: A method is provided for automatically determining a hitch raise rate calibration value for a hitch control system having a hydraulic actuator for moving the hitch, a valve for controlling flow of hydraulic fluid to the actuator and an electronic hitch control unit. The method includes applying a first control signal to the valve to cause the hitch to raise, determining a first hitch velocity as the hitch moves in response to the first control signal, and repeating these steps for a second control signal. The raise rate calibration value is then calculated as a function of a desired raise velocity, the first and second control signals and the first and second velocities.

Abstract: A hydraulic system having a standpipe in a sump with ports on the side of the standpipe and one smaller port on the top of the standpipe. The majority of the oil flows into the standpipe through the side ports thereby reducing the downward suction and flow at the top of the standpipe to eliminate the formation of a vortex at the top of the standpipe. As a result, less air is drawn into the oil producing a more consistent oil/air mixture and more consistent sump oil level.