초록 ▼

A method for estimating hydraulic pressure in a control system that includes hydraulic pressure actuators (28,30) remotely situated with respect to a pressure source (14) wherein pressure at the remote location can be estimated thereby eliminating the need for using pressure transducers to obtain a

A method for estimating hydraulic pressure in a control system that includes hydraulic pressure actuators (28,30) remotely situated with respect to a pressure source (14) wherein pressure at the remote location can be estimated thereby eliminating the need for using pressure transducers to obtain a pressure signal for use in an electronic controller (86,90,142) based on a calibratable relationship between estimated brake pressure and the difference in the volume of fluid flowing toward the pressure actuator and from the pressure actuator. An effective duty cycle for a solenoid operated fluid flow control valve (60,62) in the actuator circuit is determined in accordance with an empirical relationship between the difference between (i) the estimated brake pressure and the supply pressure and (ii) a commanded duty cycle.

대표청구항 ▼

A method for estimating pressure in a hydraulic control system having fluid pressure-operated elements, each of said fluid pressure operated elements having a fluid pressure working chamber, a pressure fluid supply line and a pressure fluid return line communicating with said pressure working chambe

A method for estimating pressure in a hydraulic control system having fluid pressure-operated elements, each of said fluid pressure operated elements having a fluid pressure working chamber, a pressure fluid supply line and a pressure fluid return line communicating with said pressure working chamber, a solenoid operated pressure distributor valve means for each pressure working chamber for forming a controlled flow restriction in said pressure supply line communicating therewith, said method including the steps of; commanding a solenoid duty cycle to establish a controlled flow restriction in the supply line and in the return line for each of said working pressure chambers; detecting a pressure differential between supply pressure in each of said supply lines and pressure on the flow return side of said pressure distributor valve means; determining an effective solenoid duty cycle for each solenoid operated distributor valve means using an empirical relationship between commanded duty cycle and effective duty cycle for various values of said differential pressure; calculating differential flow into and out of said distributor valve means in accordance with a functional relationship between estimated pressure in at least one of said pressure-operated elements and said effective duty cycle; and determining effective brake pressure in accordance with an empirical relationship between said differential flow and said estimated pressure.