TRANSMISSION CLUTCH PRESSURE CONTROLS VIA PILOT PRESSURE FEEDBACK

摘要

A transmission clutch pressure control apparatus is suitable for a configuration that includes a pilot valve and a pressure regulating valve working in tandem. The pilot valve produces a pilot pressure that varies in accordance with a pilot valve drive signal. The pressure regulating valve provides fluid to a clutch at an output clutch pressure that is in turn variable based on the pilot pressure. The apparatus includes a pilot pressure sensor in fluid communication with the pilot valve output and generates a pilot pressure signal. The apparatus also includes a control arrangement having a pilot valve pressure estimation block configured to produce a pilot pressure command in response to a clutch pressure command. The estimation block is configured to reflect the relationship between the clutch pressure and the pilot pressure. The control arrangement also includes a summer that produces an error signal based on the difference between the commanded and sensed pilot pressure. The control arrangement also includes additional control blocks implementing a control strategy that ultimately develops and output the pilot valve drive signal all based on the pilot pressure command and the pilot pressure error signal.